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Foong WC, Foong SC, Ho JJ, Gautam D, Leong JJ, Tan PY, Baskaran M. Exploring factors influencing the uptake of kangaroo mother care: key informant interviews with parents. BMC Pregnancy Childbirth 2023; 23:706. [PMID: 37789260 PMCID: PMC10548712 DOI: 10.1186/s12884-023-06021-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/22/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND The updated World Health Organization (WHO) guideline recommends immediate kangaroo mother care (KMC) for all infants, particularly those born preterm. However, its uptake and sustainability have been unsatisfactory. Therefore, we aimed to gain deeper insight into factors influencing the uptake of KMC practice in our setting, and thereby identify possible solutions for the development of relevant interventions to improve its adoption and make KMC a routine practice for all infants. METHODS Using the Triandis model of social behaviour as our framework, we conducted key informant interviews with parents and healthcare providers. Trained interviewers conducted interviews with nine parents, recruited via purposive sampling. These parents were parents of preterm infants who had been introduced to KMC. Data was transcribed and analysed based on Triandis' Theory of Interpersonal Behaviour. This paper only reports the results of the parent interviews. RESULTS Major findings were how positive feelings like warmth and contentment, the sense of parenthood with KMC, the benefits of KMC for their infant and parents being enablers for KMC uptake. Conversely, the lack of KMC awareness, the initial negative feelings such as fear, uncertainty and embarrassment, the prioritization of time for milk expression, overcrowding in the ward, lack of space and privacy, limited visiting hours, lack of support and poor communication resulting in misapprehension about KMC were major barriers. CONCLUSION A deeper understanding of the factors influencing the uptake of KMC using the Triandis behavioural model provided a way forward to help improve its uptake and sustainability in our settings. TRIAL REGISTRATION This study was registered with the National Medical Research Registry (NMRR-17-2984-39191).
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Affiliation(s)
- Wai Cheng Foong
- Department of Paediatrics, RCSI & UCD Malaysia Campus, George Town, Penang, Malaysia.
| | - Siew Cheng Foong
- Department of Paediatrics, RCSI & UCD Malaysia Campus, George Town, Penang, Malaysia
| | - Jacqueline J Ho
- Department of Paediatrics, RCSI & UCD Malaysia Campus, George Town, Penang, Malaysia
| | - Divya Gautam
- Department of Obstetrics and Gynaecology, University Hospital Galway, Galway, Ireland
| | - Jen Jen Leong
- Department of Paediatrics, Sunway Medical Centre, Perai, Penang, Malaysia
| | - Pek Yong Tan
- Department of Paediatrics, Island Hospital, George Town, Penang, Malaysia
| | - Mehala Baskaran
- Department of Paediatrics, Pulau Pinang Hospital, Ministry of Health, George Town, Penang, Malaysia
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Denny M, Baskaran M. Investigation of chemical partitioning of 7Be, 210Pb and 137Cs and novel dating of road sediment by 210Po: 210Pb disequilibrium method. Sci Total Environ 2023:164738. [PMID: 37295531 DOI: 10.1016/j.scitotenv.2023.164738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
A suite of road sediment and soil samples from a post-industrial city (Detroit, MI) were collected and analyzed for atmospherically-delivered 210Pb, 210Po, 7Be along with 226Ra and 137Cs in the bulk and size-fractionated solid samples. From the measured atmospheric depositional fluxes of 7Be, 210Po, and 210Pb, the initial 210Po/210Pb activity ratio was quantified. In all samples, there is disequilibrium between 210Po and 210Pb, with a 210Po/210Pb activity ratio (AR) of <1.0, which is reported for the first time. Using the measured 210Po/210Pb AR, the average 'apparent age' of road sediment was found to be 146 ± 62 days. Using numerical modeling, it is predicted that the (210Po/210Pb) excess activity ratio will reach a 'dynamic equilibrium' value of ~0.59 over a period of >1 year. Results from a subset of samples that were sequentially extracted for exchangeable, carbonate, Fe-Mn oxide, organic and residual phases indicate the Fe-Mn oxide fraction was found to contain the largest fraction of 7Be and 210Pb; however, the largest fraction of 210Pb was associated with the residual phase and is attributed to complexation of 210Pb with recalcitrant organic matter. This study shows that the natural tagging of 7Be and 210Po-210Pb pair via precipitation provides insights on the time scale of their mobility and adds a new dimension of time information on the pollutant-laden road sediment.
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Affiliation(s)
- M Denny
- Department of Environmental Science, Geology Wayne State University, Detroit, MI 48202, United States of America
| | - M Baskaran
- Department of Environmental Science, Geology Wayne State University, Detroit, MI 48202, United States of America.
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Behbehani M, Uddin S, Baskaran M. 210Po concentration in different size fractions of aerosol likely contribution from industrial sources. J Environ Radioact 2020; 222:106323. [PMID: 32554167 DOI: 10.1016/j.jenvrad.2020.106323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
210Po, being a highly radiotoxic isotope, could contribute to significant inhalation dose to humans. This study establishes the first set of atmospheric 210Po data in aerosol samples collected across Kuwait. The primary focus of this study is to investigate spatio-temporal variability of atmospheric 210Po and assess its sources, including anthropogenic contributions. Measurements of 210Po in aerosols collected over a period of 23 months (January 2018-November 2019) from three different locations, i.e., a remote area (120 km) north of Kuwait City, Kuwait city and an industrial site (60 km from Kuwait City center). Specific activities of 210Po were determined in 3 different size fractions (0.39-2.5 μm, 2.5-10 μm and ≥10 μm) and the highest activity was observed in the fine fraction (PM0.39- 2.5) across all sampling stations during both the summer and winter seasons. The highest activities in all the size fractions were measured downwind of the Industrial site that houses oil refineries, cement factory and some other industries including a Power and Desalination Plant. In terms of temporal variations, higher summertime activities were observed across the spatial domain. Longer residence time of atmospheric 222Rn-produced 210Pb resulting in lower scavenging of atmospheric 210Pb, due to very little precipitation in summer, will result in higher atmospheric 210Po.
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Affiliation(s)
- M Behbehani
- Environment Pollution and Climate Program, Kuwait Institute for Scientific Research, Kuwait
| | - S Uddin
- Environment Pollution and Climate Program, Kuwait Institute for Scientific Research, Kuwait.
| | - M Baskaran
- Department of Geology, Wayne State University, Detriot, MI, USA
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Baskaran M, Bianchi TS, Filley TR. Inconsistencies between 14C and short-lived radionuclides-based sediment accumulation rates: Effects of long-term remineralization. J Environ Radioact 2017; 174:10-16. [PMID: 27613199 DOI: 10.1016/j.jenvrad.2016.07.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/13/2016] [Accepted: 07/21/2016] [Indexed: 05/25/2023]
Abstract
14C is the most widely utilized geochronometer to investigate geological, geochemical and geophysical problems over the past 5 decades. Establishment of precise sedimentation rates is crucial for the reconstruction of paleo-climate, -ecological and - environmental studies when extrapolation of sedimentation rates is utilized for time scales beyond the dating range. However, agreement between short-term and long-term sedimentation rates in anthropogenically unperturbed sediment cores has not been shown. Here we show that the AMS 14C-based long-term mass accumulation rate (MAR) of an organic-rich (>70%) sediment core from Mud Lake, Florida to be ∼5 times lower than the short-term MAR obtained using 239,240Pu, 137Cs and excess 210Pb (210Pbxs). The measured sediment inventories of 210Pbxs, 137Cs and 239,240Pu are comparable to the atmospheric fallout for the sampling site, indicating very little accelerated sediment erosion over the past several decades. Presence of sharp fallout peaks of 239,240Pu indicates very little sediment mixing. The penetration depths of 137Cs and 239,240Pu were found to be much deeper than expected and this is attributed to their post-depositional mobility. MAR calculated using 14C-ages in successive layers also indicated decreasing MARs with depth, and was reflective of progressive remineralization. Using first-order kinetics, the sediment remineralization rate was found to be 4.4 × 10-4 y-1 and propose that over the long-term, remineralization of organic-rich sediment affected the long-term MAR, but not the ratio of 14C/12C. Thus, the MAR and linear sedimentation rate obtained using 14C (and other isotope-based methods) could be erroneous, although 14C ages may not be affected by such remineralization. Long-term remineralization rates of organic matter has a direct bearing on the biogeochemical cycling of elements in aqueous systems and mass balance of elements needs to be taken into consideration.
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Affiliation(s)
- M Baskaran
- Department of Geology, Wayne State University, Detroit, MI 48202, USA.
| | - T S Bianchi
- Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA
| | - T R Filley
- Department of Earth, Atmospheric, and Planetary Sciences and the Purdue Climate Change Research Center, Purdue University, West Lafayette, IN 47907, USA
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Packiaraj I, Retnakumar K, Anusuya GS, Rajambigai MA, Baskaran M, Devadoss VJ. A computed tomography study in the location of greater palatine artery in South Indian population for maxillary osteotomy. J Pharm Bioallied Sci 2016; 8:S151-S153. [PMID: 27829768 PMCID: PMC5074020 DOI: 10.4103/0975-7406.191947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 04/28/2016] [Accepted: 05/06/2016] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION The greater palatine artery is one of the important feeding vessel to the maxilla. The surgeon should know the surgical anatomy of greater palatine artery to avoid trauma in maxilla which leads to ischemic problems. AIM The CT evaluation of the distance between Pyriform aperture and the greater palatine foramen in various ages of both sexes. RESULT The distance varies according to sex and age which are measured by CT and standardised. DISCUSSION The lateral nasal osteotomy can be done upto 25 mm depth, instead of 20 mm. CONCLUSION By this study it shows that the lateral nasal wall osteotomy can be performed without injury to greater palatine artery.
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Affiliation(s)
- I. Packiaraj
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - K. Retnakumar
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - G. Sai Anusuya
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - M. Aarti Rajambigai
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - M. Baskaran
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - Vimal Joseph Devadoss
- Department of Oral and Maxillofacial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
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Srinivasan S, Choudhari NS, Baskaran M, George RJ, Shantha B, Vijaya L. Diurnal intraocular pressure fluctuation and its risk factors in angle-closure and open-angle glaucoma. Eye (Lond) 2015; 30:362-8. [PMID: 26563660 DOI: 10.1038/eye.2015.231] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 09/23/2015] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate intraocular pressure (IOP) fluctuation during office hours and its predictive factors in untreated primary angle-closure suspects (PACS); post-iridotomy primary angle closure (PAC) and primary angle-closure glaucoma (PACG) eyes with or without IOP-lowering medication(s) as appropriate and medically treated primary open-angle glaucoma (POAG) eyes. METHODS One-hundred seventeen eyes (29 PACS, 30 PAC, 28 PACG, and 30 POAG) of 117 patients were included in this cross-sectional study. The subjects underwent hourly IOP measurements with Goldmann tonometer from 0800 to 1700 hours. Subjects with PAC and PACG had laser peripheral iridotomy at least 2 weeks prior to the inclusion. SD of office-hour IOP readings was the main outcome measure. RESULTS IOP fluctuation differed between the groups (P=0.01; Kruskal-Wallis Test). Post hoc Mann-Whitney U-tests showed significantly less IOP fluctuation in PACS compared with PACG (P<0.01). Peak office-hour IOP was observed in the morning in untreated subjects and in the early afternoon in treated subjects. A stepwise linear regression model identified the presence of peripheral anterior synechiae (PAS), thickness of lens, large vertical cup-to-disc ratio (VCDR), and PAC category as significant predictive factors associated with office-hour IOP fluctuation. CONCLUSIONS Diurnal IOP fluctuation in asymptomatic PACSs was less than that in treated PACG subjects and was at least comparable to that in treated PAC and POAG subjects. The greater the amount of PAS, the thicker the lens, the larger the VCDR, the greater was the IOP fluctuation during office hours.
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Affiliation(s)
- S Srinivasan
- Elite School of Optometry, Medical Research Foundation, Chennai, India.,Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, Australia
| | - N S Choudhari
- Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India.,VST Glaucoma Centre, Dr Kallam Anji Reddy Campus, LV Prasad Eye Institute, Hyderabad, India
| | - M Baskaran
- Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India.,Singapore Eye Research Institute and Singapore National Eye Center, Singapore
| | - R J George
- Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India
| | - B Shantha
- Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India
| | - L Vijaya
- Jadhavbhai Nathamal Singhvi Glaucoma Department, Medical Research Foundation, Sankara Nethralaya, Chennai, India
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Abstract
It is universally accepted that correction of cleft lip nose deformity remains a formidable challenge for any cleft surgeon. The nose is a prominent part of the face, and hence a masterly executed cleft lip repair directs the beholders' eyes from the deformed lip to the deformed nose. A deformed nose that results from unilateral cleft of the lip and palate is likened to a tent whose one side is depressed. Many investigators believe that the deformity of the nose is produced by the malpositioning of essentially normal structures, on the other hand some cleft surgeons contend that it is the intrinsic defects in nasal structures that result in cleft nasal deformity. Depressed and hypoplastic bony scaffolding is the most important aspect of cleft nose deformity and addressing this aspect of cleft nose deformity is the secret of success of a perfect secondary rhinoplasty. Controversy still exists on timing of cleft nasal deformity. Proponents of delayed nasal repair suggest that altering the cartilages in early nasal repair at the time of lip repair would complicate future corrective nasal surgeries if the primary repair would prove unsatisfactory. The correction of nasal deformity could be performed with closed or open technique. This paper highlights one such challenging unilateral cleft lip nasal deformity in a adult patient treated by secondary rhinoplasty by open technique.
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Affiliation(s)
- M Baskaran
- Department of Oral and Maxillo Facial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - I Packiaraj
- Department of Oral and Maxillo Facial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - S Gidean Arularasan
- Department of Oral and Maxillo Facial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
| | - T K Divakar
- Department of Oral and Maxillo Facial Surgery, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
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Hong XJJ, Shinoj VK, Murukeshan VM, Baskaran M, Aung T. A simple and non-contact optical imaging probe for evaluation of corneal diseases. Rev Sci Instrum 2015; 86:093702. [PMID: 26429443 DOI: 10.1063/1.4929684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Non-contact imaging techniques are preferred in ophthalmology. Corneal disease is one of the leading causes of blindness worldwide, and a possible way of detection is by analyzing the shape and optical quality of the cornea. Here, a simple and cost-effective, non-contact optical probe system is proposed and illustrated. The probe possesses high spatial resolutions and is non-dependent on coupling medium, which are significant for a clinician and patient friendly investigation. These parameters are crucial, when considering an imaging system for the objective diagnosis and management of corneal diseases. The imaging of the cornea is performed on ex vivo porcine samples and subsequently on small laboratory animals, in vivo. The clinical significance of the proposed study is validated by performing imaging of the New Zealand white rabbit's cornea infected with Pseudomonas.
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Affiliation(s)
- Xun Jie Jeesmond Hong
- Center for Optical and Laser Engineering, School of MAE, Nanyang Technological University, Singapore 639798
| | - V K Shinoj
- Center for Optical and Laser Engineering, School of MAE, Nanyang Technological University, Singapore 639798
| | - V M Murukeshan
- Center for Optical and Laser Engineering, School of MAE, Nanyang Technological University, Singapore 639798
| | - M Baskaran
- Singapore Eye Research Institute (SERI) and Singapore National Eye Center (SNEC), 11 Third Hospital Avenue, Singapore 168751
| | - T Aung
- Singapore Eye Research Institute (SERI) and Singapore National Eye Center (SNEC), 11 Third Hospital Avenue, Singapore 168751
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Barbero L, Gázquez MJ, Bolívar JP, Casas-Ruiz M, Hierro A, Baskaran M, Ketterer ME. Mobility of Po and U-isotopes under acid mine drainage conditions: an experimental approach with samples from Río Tinto area (SW Spain). J Environ Radioact 2014; 138:384-389. [PMID: 24308958 DOI: 10.1016/j.jenvrad.2013.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 06/02/2023]
Abstract
Under acid mine drainage (AMD) conditions, the solubilities and mobilities of many elements are vastly different from conditions prevailing in most natural waters. Studies are underway in the Río Tinto area (Iberian Pyrite Belt), in order to understand the behavior and mobility of long-lived U-series radionuclides under AMD conditions. A set of leaching experiments utilizing typical country rocks from the Tinto River basin, waste rock pile composite materials, iron-rich riverbed sediments and gossan (weathered naturally rock) were performed towards this purpose. Initial leaching experiments using distilled water kept in contact with solid material for 300, 100, 50 and 1 h resulted in very low concentrations of U with (234)U/(238)U activity ratios close to equilibrium and activity concentrations of (210)Po < 0.03 mBq/g. Leaching experiments performed with sulfuric acid media (0.1 and 0.01 M), and contact times between the solid and solution for 24 h were conducted to quantify the amount of U-isotopes and (210)Po leached, and the radioactive disequilibria generated between the radionuclides in the leachate. These experiments show that Po mobility in acidic conditions (pH around 1-2) is very low, with (210)Po activity in the leachate to be 6% in average for the solid sample. By contrast, mobility of U-isotopes is higher than that of Po, around 1.2%.
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10
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Mudbidre R, Baskaran M, Schweitzer L. Investigations of the partitioning and residence times of Po-210 and Pb-210 in a riverine system in Southeast Michigan, USA. J Environ Radioact 2014; 138:375-383. [PMID: 24525180 DOI: 10.1016/j.jenvrad.2014.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 01/12/2014] [Accepted: 01/15/2014] [Indexed: 06/03/2023]
Abstract
Some of the daughter products in the (222)Rn-decay series, such as (210)Po and (210)Pb, have been widely used as tracers and chronometers in aqueous systems. We measured the concentrations of (210)Pb and (210)Po in the dissolved (≤0.5 μm), bulk (unfiltered) and particulate phases (≥1 μm) collected in the Clinton River in the Lake St. Clair watershed in Southeast Michigan in order to investigate their partitioning between particulate and dissolved phases. Activity measurements of the dissolved and particulate phases revealed that an average of 38% (range: 12-59%) and 33% (range: 12-66%) of the total (210)Pb and (210)Po, respectively, in the water column was found in the particulate phase. The activity of dissolved and total (210)Pb was higher than that of (210)Po because of the higher atmospheric depositional fluxes of (210)Pb compared to (210)Po. Although the calculated Kd values of (210)Pb and (210)Po were similar, there was an inverse relationship between the Kd and suspended particulate matter concentration, indicating the presence of a particle concentration effect and we attribute this observation to the presence of significant amounts of colloidal (210)Po and (210)Pb in the dissolved phase. The fractionation factors for Po and Pb were found to be less than 1 in most cases. The first-order box model calculation-based residence times with respect to scavenging varied from 2 to 25 days for (210)Pb and 19-78 days for (210)Po, indicating higher particle-reactivity of (210)Pb compared to (210)Po.
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Affiliation(s)
- R Mudbidre
- R.V. College of Engineering, Bangalore 560059, India.
| | - M Baskaran
- Department of Geology, Wayne State University, Detroit, MI 48202, USA
| | - L Schweitzer
- Department of Chemistry, Oakland University, Rochester, MI, USA
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Shinoj VK, Murukeshan VM, Baskaran M, Aung T. Note: A gel based imaging technique of the iridocorneal angle for evaluation of angle-closure glaucoma. Rev Sci Instrum 2014; 85:066105. [PMID: 24985869 DOI: 10.1063/1.4882335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Noninvasive medical imaging techniques have high potential in the field of ocular imaging research. Angle closure glaucoma is a major disease causing blindness and a possible way of detection is the examination of the anterior chamber angle in eyes. Here, a simple optical method for the evaluation of angle-closure glaucoma is proposed and illustrated. The light propagation from the region associated with the iridocorneal angle to the exterior of eye is considered analytically. The design of the gel assisted probe prototype is carried out and the imaging of iridocorneal angle is performed on an eye model.
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Affiliation(s)
- V K Shinoj
- Center for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - V M Murukeshan
- Center for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - M Baskaran
- Singapore Eye Research Institute (SERI) and Singapore National Eye Center (SNEC), 11 Third Hospital Avenue, Singapore 168751
| | - T Aung
- Singapore Eye Research Institute (SERI) and Singapore National Eye Center (SNEC), 11 Third Hospital Avenue, Singapore 168751
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12
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Rodrigo JF, Casas-Ruiz M, Vidal J, Barbero L, Baskaran M, Ketterer ME. Application of (234)U/(238)U activity ratios to investigations of subterranean groundwater discharge in the Cádiz coastal area (SW Spain). J Environ Radioact 2014; 130:68-71. [PMID: 24463722 DOI: 10.1016/j.jenvrad.2014.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 11/26/2013] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
The activity ratios of (234)U/(238)U were used to investigate processes of subterranean groundwater discharge into coastal marine waters in a study location at Bay of Cádiz (southwest Spain). Marine waters in the bay and surrounding open ocean exhibited U concentrations of 3.4 ± 0.1 μg/L and activity ratios of 1.15 ± 0.01, in agreement with the expected composition of seawater ((234)U/(238)U activity ratio = 1.148 ± 0.002). Three water samples obtained from the discharge zone of the Guadalete River exhibited activity ratios of 1.17-1.22 along with slightly lower U concentrations compared to seawater, which is likely due to mixing between seawater and a groundwater end-member. One possible source of groundwater was characterized by sampling and analyzing a well water sample collected in the neighboring village of El Puerto de Santa María; this water sample exhibited an activity ratio of 1.34 ± 0.03 and a U concentration of 1.22 μg/L. Water from the Guadelete River estuarine zone can be explained to result from a two-component mixture of seawater and groundwater from the El Puerto de Santa María well; however, if there are several groundwater reservoirs with different U activity ratios that discharge to the coastal water, then, it may be difficult and more studies are being conducted to address this issue.
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Affiliation(s)
- J F Rodrigo
- Departamento de Física Aplicada, Universidad de Cádiz, Av. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain
| | - M Casas-Ruiz
- Departamento de Física Aplicada, Universidad de Cádiz, Av. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain.
| | - J Vidal
- Departamento de Construcciones Navales, Universidad de Cádiz, Av. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain
| | - L Barbero
- Departamento de Ciencias de la Tierra, Universidad de Cádiz, Av. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain
| | - M Baskaran
- Department of Geology, Wayne State University, Detroit, MI 48202, USA
| | - M E Ketterer
- Department of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, AZ 86011-5698, USA
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13
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Hong GH, Hernández-Ceballos MA, Lozano RL, Kim YI, Lee HM, Kim SH, Yeh SW, Bolívar JP, Baskaran M. Radioactive impact in South Korea from the damaged nuclear reactors in Fukushima: evidence of long and short range transport. J Radiol Prot 2012; 32:397-411. [PMID: 23006667 DOI: 10.1088/0952-4746/32/4/397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Traces of long-lived fallout-derived radioisotopes ((134)Cs and (137)Cs) were found in wet and dry deposition samples collected from the west and east coasts of South Korea from March to May 2011 following the release of radionuclides from the damaged nuclear power plants in Fukushima, Japan. The analysis of air mass back trajectory and atmospheric pressure systems indicated that the Fukushima-derived radiocaesium had predominantly reached South Korea from the west by surface westerlies from 11 March to 5 April; however, after 6 April, air masses arrived from Japan directly due to a high pressure system that developed to the east of Japan. Spatial variation of deposition fluxes of radiocaesium in South Korea was partly attributed to the presence of local longitudinal orography.
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Affiliation(s)
- G H Hong
- Institute of Ocean Science and Technology, Ansan, Korea
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Hernández-Ceballos MA, Hong GH, Lozano RL, Kim YI, Lee HM, Kim SH, Yeh SW, Bolívar JP, Baskaran M. Tracking the complete revolution of Surface Westerlies over Northern Hemisphere using radionuclides emitted from Fukushima. Sci Total Environ 2012; 438:80-85. [PMID: 22975305 DOI: 10.1016/j.scitotenv.2012.08.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/13/2012] [Accepted: 08/06/2012] [Indexed: 06/01/2023]
Abstract
Massive amounts of anthropogenic radionuclides were released from the nuclear reactors located in Fukushima (northeastern Japan) between 12 and 16 March 2011 following the earthquake and tsunami. Ground level air radioactivity was monitored around the globe immediately after the Fukushima accident. This global effort provided a unique opportunity to trace the surface air mass movement at different sites in the Northern Hemisphere. Based on surface air radioactivity measurements around the globe and the air mass backward trajectory analysis of the Fukushima radioactive plume at various places in the Northern Hemisphere by employing the Hybrid Single-Particle Lagrangian Integrated Trajectory model, we show for the first time, that the uninterrupted complete revolution of the mid-latitude Surface Westerlies took place in less than 21 days, with an average zonal velocity of>60 km/h. The position and circulation time scale of Surface Westerlies are of wide interest to a large number of global researchers including meteorologists, atmospheric researchers and global climate modellers.
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Liu J, Yin FS, Wong DWK, Zhang Z, Tan NM, Cheung CY, Baskaran M, Aung T, Wong TY. Automatic glaucoma diagnosis from fundus image. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2011:3383-6. [PMID: 22255065 DOI: 10.1109/iembs.2011.6090916] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Glaucoma is currently diagnosed by glaucoma specialists using specialized imaging devices like HRT and OCT. Fundus imaging is a modality widely used in primary healthcare. An automatic glaucoma diagnosis system based on fundus image can be deployed to primary healthcare clinics and has potential for early disease diagnosis. A mass glaucoma screening program can also be facilitated using such a system. We present an automatic fundus image based cup-to-disc ratio measurement system; and demonstrate its potential for automatic objective glaucoma diagnosis and screening. It provides strong support to use fundus image as the modality for automatic glaucoma diagnosis.
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Affiliation(s)
- J Liu
- Institute for Infocomm Research, A*STAR, Singapore.
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16
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Du JZ, Zhang J, Baskaran M. Applications of Short-Lived Radionuclides (7Be, 210Pb, 210Po, 137Cs and 234Th) to Trace the Sources, Transport Pathways and Deposition of Particles/Sediments in Rivers, Estuaries and Coasts. Advances in Isotope Geochemistry 2012. [DOI: 10.1007/978-3-642-10637-8_16] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Lozano RL, San Miguel EG, Bolívar JP, Baskaran M. Depositional fluxes and concentrations of7Be and210Pb in bulk precipitation and aerosols at the interface of Atlantic and Mediterranean coasts in Spain. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015675] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Baskaran M. Po-210 and Pb-210 as atmospheric tracers and global atmospheric Pb-210 fallout: a review. J Environ Radioact 2011; 102:500-13. [PMID: 21093126 DOI: 10.1016/j.jenvrad.2010.10.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 09/24/2010] [Accepted: 10/17/2010] [Indexed: 05/06/2023]
Abstract
Over the past ∼ 5 decades, the distribution of (222)Rn and its progenies (mainly (210)Pb, (210)Bi and (210)Po) have provided a wealth of information as tracers to quantify several atmospheric processes that include: i) source tracking and transport time scales of air masses; ii) the stability and vertical movement of air masses iii) removal rate constants and residence times of aerosols; iv) chemical behavior of analog species; and v) washout ratios and deposition velocities of aerosols. Most of these applications require that the sources and sink terms of these nuclides are well characterized. Utility of (210)Pb, (210)Bi and (210)Po as atmospheric tracers requires that data on the (222)Rn emanation rates is well documented. Due to low concentrations of (226)Ra in surface waters, the (222)Rn emanation rates from the continent is about two orders of magnitude higher than that of the ocean. This has led to distinctly higher (210)Pb concentrations in continental air masses compared to oceanic air masses. The highly varying concentrations of (210)Pb in air as well the depositional fluxes have yielded insight on the sources and transit times of aerosols. In an ideal enclosed air mass (closed system with respect to these nuclides), the residence times of aerosols obtained from the activity ratios of (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb are expected to agree with each other, but a large number of studies have indicated discordance between the residence times obtained from these three pairs. Recent results from the distribution of these nuclides in size-fractionated aerosols appear to yield consistent residence time in smaller-size aerosols, possibly suggesting that larger size aerosols are derived from resuspended dust. The residence times calculated from the (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb activity ratios published from 1970's are compared to those data obtained in size-fractionated aerosols in this decade and possible reasons for the discordance is discussed with some key recommendations for future studies. The existing global atmospheric inventory data of (210)Pb is re-evaluated and a 'global curve' for the depositional fluxes of (210)Pb is established. A current global budget for atmospheric (210)Po and (210)Pb is also established. The relative importance of dry fallout of (210)Po and (210)Pb at different latitudes is evaluated. The global values for the deposition velocities of aerosols using (210)Po and (210)Pb are synthesized.
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Affiliation(s)
- M Baskaran
- Department of Geology, Wayne State University, Detroit, MI-48202, USA.
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Baskaran M. Chapter-10 Primary Open-Angle Glaucoma. Clin Ophthalmol 2011. [DOI: 10.5005/jp/books/11246_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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20
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Baskaran M. Chapter-06 Automated Visual Field Assessment, Optic Nerve and Nerve Fiber Layer Imaging. Clin Ophthalmol 2011. [DOI: 10.5005/jp/books/11246_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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George R, Arvind H, Baskaran M, Ramesh SV, Raju P, Vijaya L. The Chennai glaucoma study: prevalence and risk factors for glaucoma in cataract operated eyes in urban Chennai. Indian J Ophthalmol 2010; 58:243-5. [PMID: 20413933 PMCID: PMC2886261 DOI: 10.4103/0301-4738.62655] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
We report the prevalence and risk factors for glaucoma among aphakes and pseudophakes in 3850 subjects who participated in a population-based study in urban south India. The subjects underwent an ophthalmic examination including applanation tonometry, gonioscopy, optic disc evaluation and frequency doubling perimetry. Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. Thirty eight, 15 aphakes and 23 pseudophakes (0.99% of 3850 subjects) of the 406 persons who had undergone cataract surgery were diagnosed with glaucoma. Aphakes/pseudophakes were at higher risk of glaucoma as compared to the phakic population (Odds Ratio: 2.71, 95% CI: 1. 94, 3.38, p=0.001). On multivariate analysis, older age and higher intra ocular pressure were risk factors for glaucoma. Blindness attributable to glaucoma was detected in 20% of aphakic and 4.3% of pseudophakic eyes. Glaucoma was a significant cause of morbidity in those who had undergone cataract surgery in this urban population.
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Affiliation(s)
- Ronnie George
- Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India
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Abstract
The aim of the study was to assess agreement between two
commercially available applanation tonometers for the
measurement of intraocular pressure (IOP). Forty subjects
underwent IOP measurement on two accurately calibrated
Goldmann type applanation tonometers (Zeiss AT 030 (GATZ)
and Inami L-5110(GATI)). The order of examination was
randomized and observers were masked to the IOP recorded.
The mean of two consecutive readings, from a randomly selected
eye for each subject, was used for analysis. Agreement was
assessed using the Altman and Bland plot. The mean (SD) IOP
readings on GATZ was 15.32 (±6.80) mm Hg and on GATI was
13.52 (±5.65) mm Hg (p<0.001, 95% CI of the difference: -2.48 to
-1.11). The 95% limits of agreement on the Altman and Bland plot
were:-2.47 to 6.16 mm Hg). There was significant inter-instrument
variability between the two accurately calibrated Goldmann type
applanation tonometers studied.
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Affiliation(s)
- Ronnie George
- Glaucoma Services, Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India.
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Vijaya L, George R, Arvind H, Baskaran M, Ve Ramesh S, Raju P, Kumaramanickavel G, McCarty C. Prevalence of Primary Angle-Closure Disease in an Urban South Indian Population and Comparison with a Rural Population. Ophthalmology 2008; 115:655-660.e1. [PMID: 17869343 DOI: 10.1016/j.ophtha.2007.05.034] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 05/18/2007] [Accepted: 05/18/2007] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVE To determine the prevalence of primary angle-closure glaucoma (PACG), primary angle closure (PAC), and PAC suspect (PACS) in an urban population, and to compare prevalence and associated risk factors with a rural population. DESIGN Population-based cross-sectional study. PARTICIPANTS Four thousand eight hundred subjects 40 years or older were selected from Chennai city using multistage random cluster sampling. INTERVENTION All subjects had a complete ophthalmic examination that included logarithm of the minimum angle of resolution visual acuity, applanation tonometry, gonioscopy, grading of lens opacities, dilated fundus examination, optic disc photography, and visual fields. MAIN OUTCOME MEASURES Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology classification. RESULTS Three thousand eight hundred fifty (80.2%) responded; 34 subjects (17 female, 17 male) had PACG (0.88%; 95% confidence interval [CI], 0.60-1.16). The mean intraocular pressure (IOP) was 26.0+/-14.9 mmHg. Five subjects (14.7%) had been previously diagnosed to have glaucoma, 1 of whom had undergone glaucoma surgery and 2 of whom had been diagnosed to have open-angle glaucoma. Two subjects (5.9%) were bilaterally and 3 subjects (8.8%) were unilaterally blind. One hundred six subjects (2.75%; 95% CI, 2.01-3.49) were diagnosed to have PAC (62 female, 44 male). Thirty-nine subjects (36.8%) had presenting IOP > 24 mmHg, 83 (78.3%) had peripheral anterior synechiae, and 16 (15.1%) had both. Two hundred seventy-eight subjects (7.24%; 95% CI, 6.38-8.02) had PACS (183 female, 95 male). Prevalences of PACG and PACS were similar in the urban and rural populations. Primary angle closure prevalence was higher in the urban population (P<0.0001). Primary angle closure and PACG were positively associated with increasing age and IOP in both populations and were more common in rural women (odds ratio [OR], 4.3; 95% CI, 2.2-8.3). Association with hyperopia was seen only in the urban population (OR, 2.0; 95% CI, 1.4-2.8). CONCLUSIONS Prevalences of PACG and PACS were similar in the rural and urban populations; PAC was more common in the urban population. In both groups, the disease was asymptomatic. Poor detection rates were probably due to lack of gonioscopy as a routine part of an eye examination.
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Affiliation(s)
- Lingam Vijaya
- Glaucoma Project, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
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Vijaya L, George R, Baskaran M, Arvind H, Raju P, Ramesh SV, Kumaramanickavel G, McCarty C. Prevalence of Primary Open-angle Glaucoma in an Urban South Indian Population and Comparison with a Rural Population. Ophthalmology 2008; 115:648-654.e1. [PMID: 17664010 DOI: 10.1016/j.ophtha.2007.04.062] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Revised: 04/08/2007] [Accepted: 04/17/2007] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To estimate the prevalence and risk factors of primary open-angle glaucoma (POAG) in an urban population and compare the same with that of our published rural population data in southern India. DESIGN Population-based cross-sectional study. PARTICIPANTS Four thousand eight hundred subjects 40 years or older were selected using a multistage random cluster sampling procedure in Chennai city. INTERVENTION Three thousand eight hundred fifty (80.2%) subjects underwent a complete ophthalmic examination, including applanation tonometry, gonioscopy, pachymetry, optic disc photography, and automated perimetry. MAIN OUTCOME MEASURES Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology Classification. RESULTS The distribution of intraocular pressure (IOP) and vertical cup-to-disc ratio (VCDR) was obtained from the right eye of the 2532 subjects with normal suprathreshold visual fields. Mean IOP was 16.17+/-3.74 mmHg (97.5th and 99.5th percentiles, 24 mmHg and 30 mmHg). The mean VCDR was 0.43+/-0.17 (97.5th and 99.5th percentiles, 0.7 and 0.8). One hundred thirty-five (64 men, 71 women) subjects had POAG (3.51%; 95% confidence interval [CI], 3.04-4.0). Primary open-angle glaucoma subjects (58.4+/-11.3 years) were older (P<0.0001) than the study population (54.8+/-10.6 years). One hundred twenty-seven (94%) subjects were diagnosed to have POAG for the first time. Two subjects (1.5%) were bilaterally blind, and 3 (3.3%) were unilaterally blind due to POAG. The urban population prevalence was more than that of the rural population (1.62%; 95% CI, 1.4%-1.8%; P<0.0001). In both populations, increasing IOP (per millimeter of mercury) and older age were associated with the disease. There was no association with gender, myopia, systemic hypertension, diabetes, or central corneal thickness. CONCLUSIONS The prevalence of POAG in a > or =40-year-old south Indian urban population was 3.51%, higher than that of the rural population. The prevalence increased with age, and >90% were not aware of the disease.
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Affiliation(s)
- Lingam Vijaya
- Glaucoma Project, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
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25
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Narayanaswamy A, Neog A, Baskaran M, George R, Lingam V, Desai C, Rajadhyaksha V. A randomized, crossover, open label pilot study to evaluate the efficacy and safety of Xalatan ® in comparison with generic Latanoprost (Latoprost) in subjects with primary open angle glaucoma or ocular hypertension. Indian J Ophthalmol 2007; 55:127-31. [PMID: 17322603 DOI: 10.4103/0301-4738.30707] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
AIM To compare the efficacy and tolerability of Xalatan with generic latanoprost (Latoprost) in subjects with primary open angle glaucoma (POAG) or ocular hypertension (OH). MATERIALS AND METHODS This was a single-center, randomized, open label, crossover, two period comparative study. At the baseline visit, subjects were randomized to two groups. Group A received Xalatan for weeks 1-12 followed by Latoprost for weeks 13-24. Group B received Latoprost for weeks 1-12 followed by Xalatan for weeks 13-24. RESULTS 30 subjects were recruited, 12 in Group A and 18 in Group B. In subjects administered Xalatan, intraocular pressure (IOP) showed a greater decrease (P < 0.001) from 23.64 +/- 3.13 mmHg at baseline to 14.29 +/- 1.61 mmHg at week 12 (fall of 9.35 +/- 3.55 mmHg, 38.66% +/- 10.29) than that seen in the Latoprost group (22.74 +/- 2.47 mmHg to 16.98 +/- 2.49 mmHg, fall of 5.76 +/- 1.41 mmHg; 25.42% +/- 5.98). In period 2 when subjects were crossed over to Xalatan from Latoprost, there was a further fall from 16.98 +/- 2.49 mmHg to 16.09 +/- 1.49 at week 24 (fall of 0.89 +/- 1.59 mmHg; 4.3% +/- 8.76). However, when subjects were crossed over to Latoprost from Xalatan, the IOP rose from 14.29 +/- 1.61 mmHg to 15.36 +/- 1.71 mmHg at week 24 (8.86% +/- 17.76). There was no significant difference in incidence of conjunctival hyperemia or any other adverse events in both the groups. CONCLUSION The magnitude of IOP lowering in patients with POAG and OH with Xalatan and Latoprost is different. In our study, the IOP lowering with Xalatan was higher than that with Latoprost.
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Abstract
AIM To investigate the association between central corneal thickness (CCT) and the degree of myopia among Chinese. METHODS In this prospective observational study, 714 consecutive patients were recruited from a refractive surgery clinic. CCT was measured in both eyes of each patient using the Orbscan (Bausch and Lomb, Rochester, New York, USA), and data of the right eye were selected for analysis. CCT was correlated with the degree of myopia in dioptres (D) using Pearson's correlation coefficient and Dunnett's t test with multiple comparisons. RESULTS The age of the patients ranged from 15 to 59 years. The mean CCT was 534.5 microm, with a standard deviation (SD) of 38.1 (range 305-684) microm. The mean (SD) myopic spherical equivalent was 5.30 (2.74) D, range -17.5--0.625 D. No correlation was found between CCT and the degree of myopia (r = -0.13, p = 0.719). CONCLUSIONS Among Chinese with myopia, CCT was distributed over a large range but did not correlate with the degree of myopia.
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Affiliation(s)
- H-B Fam
- Tan Tock Seng Hospital, The Eye Institute, Singapore
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Sripriya S, Nirmaladevi J, George R, Hemamalini A, Baskaran M, Prema R, Ve Ramesh S, Karthiyayini T, Amali J, Job S, Vijaya L, Kumaramanickavel G. OPTN gene: profile of patients with glaucoma from India. Mol Vis 2006; 12:816-20. [PMID: 16885925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
PURPOSE Optineurin gene (OPTN) mutations are reported in primary open angle glaucoma patients (POAG) from different populations. The coding and noncoding regions of OPTN were screened for mutations in 100 Indian high tension glaucoma patients (HTG). The frequency of the OPTN M98K mutation in an additional 120 patients (70 HTG and 50 normal tension glaucoma [NTG]) was analyzed by restriction enzyme digestion. METHODS The HTG patients (about 40 years of age) were characterized by open angles on gonioscopy, with raised intraocular pressure (IOP) more than 21 mmHg (<21 mmHg on office diurnal phasing for NTG), and typical glaucomatous disc changes with corresponding visual field defects in the absence of any secondary cause. One hundred HTG patients and controls were screened for OPTN mutations by direct sequencing using an ABI prism 310/3100 Avant genetic analyzer. The M98K status was analyzed by restriction enzyme digestion with StuI. A genotype/phenotype correlation was also attempted for OPTN sequence alterations with clinical parameters such as age at diagnosis, intraocular pressure, cup:disc ratio, etc. The putative change in the transcription factor binding site for the IVS7 +24G>A polymorphism was attempted with AliBaba software (version 2.1). RESULTS Six sequence alterations were observed in the 100 POAG patients by direct sequencing. The M98K substitution was observed in a total of 10 patients (7/170 HTG and 3/50 NTG) contributing to 4.1% in HTG and 6% in the NTG group and not in the controls. The IVS7+24G>A nucleotide change showed a significant difference in the HTG group (7/100) when compared to the control group (0/100) and found to be associated with increased IOP at diagnosis (p=0.03). The IVS7+24G>A polymorphism resulted in the creation of binding sites for transcription factors NF-1 and CPE that were not present in the wild type. CONCLUSIONS The current study suggests a possible role of SNPs rather than mutations in OPTN in POAG pathology in the Indian population.
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Affiliation(s)
- S Sripriya
- Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
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Abstract
AIM To study the influence of tobacco use on cataract formation in a rural South Indian population. METHODS 3924 subjects from the Chennai Glaucoma Study conducted in rural south India underwent a comprehensive eye examination, including Lens Opacities Classification System II grading. Information on tobacco use, type of tobacco (smoking and smokeless), duration and quantity of use was collected. RESULTS 1705 (male:female (M:F) 1106:599) people used tobacco and were significantly older (mean (standard deviation (SD)) age 55.80 (10.64) years) than non-users (52.23 (10.51); p<0.001). 731 (M:F 730:1) people smoked, 900 (M:F 302:598) used smokeless tobacco, and 74 (M:F, 74:0) used tobacco in both forms. The unadjusted and adjusted (age and sex) odds ratio (OR) for a positive history of tobacco use and cataract was 1.72 (95% confidence interval (CI) 1.51 to 1.96) and 1.39 (95% CI 1.15 to 1.68), respectively. The unadjusted OR for smokers and smokeless tobacco users was 1.04 (95% CI 0.88 to 1.23) and 2.74 (95% CI 2.31 to 3.26), respectively. The adjusted OR was 1.19 (95% CI 0.89 to 1.59) and 1.54 (95% CI 1.22 to 1.95), respectively. No significant association was noted between smoking and any particular type of cataract. Smokeless tobacco use was found to be significantly associated with nuclear cataract even after adjusting for age and sex (OR 1.67, p = 0.067, 95% CI 1.16 to 2.39). CONCLUSION Tobacco use was significantly associated with cataract. Smoking was not found to be significantly associated with cataract formation; however, smokeless tobacco use was more strongly associated with cataract.
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Affiliation(s)
- P Raju
- Medical Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, India 600006
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Gunvant P, Baskaran M, Vijaya L, Hansen BC, Joseph IS, Watkins RJ, Broadway DC, O'Leary DJ. Comparison of pulsatile ocular blood flow in Indians and Europeans. Eye (Lond) 2006; 19:1163-8. [PMID: 15389264 DOI: 10.1038/sj.eye.6701710] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To compare pulsatile ocular blood flow (POBF) in Europeans and Indians and provide reference values for a group of healthy Indians. PATIENTS AND METHODS Measurement with the POBF Tonograph was performed on healthy Indian subjects in India (n=252). A further 80 subjects (40 of Indian descent and 40 Europeans) underwent measurements in Cambridge, England. The instrument used for measurement was the same for both the studies. RESULTS The mean POBF in the Indians in India was found to be 1176 microl/min. The mean POBF value in the Europeans was found to be 1033 microl/min and that for Indians in England was 1061 microl/min. The difference between the POBF within groups was significant (one-way ANOVA P<0.05) with the POBF of Indians in India being higher than Europeans and Indians in the UK. The difference between the Europeans and Indians in the UK did not reach statistical significance. CONCLUSIONS POBF values in Indians living in India were found to be considerably higher than the previously published normal value of 650 microl/min in European studies and other studies for other racial groups. The reason for this apparent difference may be instrument-related rather than genetic because such a large difference was not observed when a comparison was performed in the UK. In addition, the results for both groups in our comparative study were still considerably higher than reported in previous studies. The POBF of Indians in India is slightly higher than the POBF of people of Indian ethnic origin in England.
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Affiliation(s)
- P Gunvant
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY 40292, USA.
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Vijaya L, George R, Arvind H, Baskaran M, Raju P, Ramesh SV, Paul PG, Kumaramanickavel G, McCarty C. Prevalence and causes of blindness in the rural population of the Chennai Glaucoma Study. Br J Ophthalmol 2006; 90:407-10. [PMID: 16547314 PMCID: PMC1857022 DOI: 10.1136/bjo.2005.081406] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2005] [Indexed: 10/24/2022]
Abstract
AIM To study the prevalence and causes of blindness in a rural south Indian population. METHODS 3924/4800 enumerated (81.75%) subjects, aged 40 years or more from rural Tamil Nadu, underwent comprehensive ophthalmic examination-visual acuity, refraction, intraocular pressure, gonioscopy, cataract grading (LOCS II), retinal examination, and SITA Standard where indicated. Blindness was defined using WHO criteria as best corrected visual acuity of less than 3/60 and/or visual field of less than 10 degrees in the better eye. The influence of age, sex, literacy, and occupation was assessed using multiple logistic regression. RESULTS 753 subjects (19.2%; 321 males, 432 females) presented with a visual acuity of <3/60; 132 subjects (3.36%, 95% CI: 2.80 to 3.93) were diagnosed to be blind. Cataract was responsible in 74.62% of eyes; glaucoma, cystoid macular oedema, optic atrophy, and corneal scars accounted for 3.79% each. Bilateral causes of blindness were cataract (78.63%), glaucoma (4.29%), optic atrophy (3.42%), cystoid macular oedema, and corneal scars (2.56% each). In 19 eyes (7.2%) the blindness was probably related to cataract surgery. Blindness was positively associated with increasing age (p<0.0001). CONCLUSION 3.36% of the studied rural population was bilaterally blind, with cataract being the single most important cause.
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Affiliation(s)
- L Vijaya
- Vision Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, India 600 006.
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Vijaya L, George R, Arvind H, Baskaran M, Paul PG, Ramesh SV, Raju P, Kumaramanickavel G, McCarty C. Prevalence of Angle-Closure Disease in a Rural Southern Indian Population. ACTA ACUST UNITED AC 2006; 124:403-9. [PMID: 16534061 DOI: 10.1001/archopht.124.3.403] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To estimate the prevalence of primary angle-closure glaucoma, primary angle closure (PAC), and primary angle-closure suspect (PACS) and its associated risk factors in a rural population in southern India. METHODS Three thousand and nine hundred thirty-four (81.95%) of 4800 enumerated subjects aged 40 years or older underwent a complete ophthalmic examination, including compression gonioscopy. Glaucoma was diagnosed using International Society of Geographical and Epidemiological Ophthalmology classification. RESULTS Data were analyzed for 3924 subjects (81.75%). Primary angle-closure glaucoma was diagnosed in 34 subjects (0.87%; 95% confidence interval [CI], 0.58 to 1.16) (27 women, 7 men). The mean intraocular pressure was 20.71 +/- 9.24 mm Hg. One subject (2.94%) was blind. Twenty-eight subjects (0.71%; 95% CI, 0.45 to 0.98) were diagnosed to have PAC (21 women, 7 men). Eleven subjects (39.3%) had an intraocular pressure greater than 21 mm Hg, 13 subjects (46.43%) had peripheral anterior synechiae, and 4 subjects (14.29%) had both. Two hundred forty-six subjects (6.27%; 95% CI, 5.51 to 7.03) had PACS (168 women, 78 men). Primary angle closure and primary angle-closure glaucoma were more common in women (age-adjusted odds ratio, 3.02; 95% CI, 1.66 to 5.51) with an increasing prevalence with age. Increasing intraocular pressure was associated with the disease (odds ratio, 1.14; 95% CI, 1.09 to 1.19). There was no association with hypertension and hyperopia. Axial length and anterior chamber depth were longer in the normal group than in the 3 groups with angle closure (P<.05). Women had shorter axial lengths than men (P<.001) in the angle closure groups. CONCLUSIONS The overall prevalence of primary angle closures (PAC and primary angle-closure glaucoma) in a rural population of southern India was 1.58%. There was a female preponderance, and the disease tends to be asymptomatic.
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Affiliation(s)
- Lingam Vijaya
- Glaucoma Project, Vision Research Foundation, Sankara Nethralaya, Chennai, India and Marshfield Clinic Research Foundation, Marshfield, Wis, USA.
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Sreenivasan V, Ve Ramesh S, George R, Baskaran M. Frosted cylindrical lens induced artefact on Humphrey automated perimetry. Clin Exp Optom 2006; 89:26-9. [PMID: 16430437 DOI: 10.1111/j.1444-0938.2006.00002.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The aim of this study was to assess the effect of a cylindrical corrective lens with frosted sides on Humphrey automated perimetry performed with a translucent spectacle occluder in the contralateral eye. METHODS Ten healthy volunteers with cylindrical refractive errors of more than 1.50 DC had Humphrey visual fields (30-2) measured with the contralateral eye occluded with either a translucent spectacle occluder or an opaque patch. The order of testing with each occluder was randomised. Additionally, visual field examination with the opaque patch was performed on three volunteer subjects with deep-set eyes to establish the clinical significance of the frosted cylindrical lens induced artefact (CLA). The back vertex distances for the correcting lenses were measured for all tests. RESULTS Eight out of 10 volunteers tested with the translucent occluder demonstrated CLA, which was absent when the opaque patch was used. The presence of an artefact corresponding to the axis of the cylinder was observed, when the vertex distance was more than 15 mm. Three subjects with deep-set eyes presented with CLA, even with the use of an opaque patch. DISCUSSION Cylindrical lens artefacts can occur with increasing vertex distance when using a translucent spectacle occluder instead of an opaque patch. CLA is also seen in subjects with deep-set eyes.
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Affiliation(s)
- V Sreenivasan
- Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India
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Arvind H, George R, Raju P, Ramesh SV, Baskaran M, Paul PG, McCarty C, Vijaya L. Glaucoma in aphakia and pseudophakia in the Chennai Glaucoma Study. Br J Ophthalmol 2005; 89:699-703. [PMID: 15923505 PMCID: PMC1772656 DOI: 10.1136/bjo.2004.056234] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To determine the prevalence of glaucoma among aphakes and pseudophakes in a rural population of southern India. METHODS 3924 subjects aged 40 years or above underwent complete ophthalmic examination. Glaucoma in aphakia/pseudophakia was diagnosed using International Society of Geographical and Epidemiological Ophthalmology criteria in aphakic/pseudophakic people. RESULTS 54 subjects (37 aphakes, 17 pseudophakes) (1.38% of 3924 subjects, 11.2% of 482 aphakes/pseudophakes) had glaucoma in aphakia/pseudophakia. Aphakia, age, intraocular pressure (IOP), pseudoexfoliation, and peripheral anterior synechiae greater than or equal to 180 degrees of the angle were risk factors for glaucoma on univariate analysis. On multivariate analysis, IOP and aphakia were independent risk factors for glaucoma. 39 people (72.22%) with glaucoma had normal IOP at presentation. None of the people with glaucoma were aware of the disease. Blindness in one or both eyes was seen in 12 subjects (10 unilateral and two bilateral)-that is, 22.22% of people with glaucoma in aphakia/pseudophakia. CONCLUSIONS Glaucoma is an important cause of ocular morbidity among aphakes and pseudophakes in this rural population of south India. This glaucoma, responsible for unilateral or bilateral blindness in 22.2% of those affected, was entirely undetected in this study population.
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Affiliation(s)
- H Arvind
- Medical Research Foundation, Vision Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, India-600 006
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Thomas R, Parikh R, Sood D, Vijaya L, Sekhar GC, Sood NN, Baskaran M, Prasad KK. Efficacy and safety of latanoprost for glaucoma treatment: a three-month multicentric study in India. Indian J Ophthalmol 2005; 53:23-30. [PMID: 15829743 DOI: 10.4103/0301-4738.15281] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
PURPOSE To evaluate the short-term efficacy and safety of 0.005% topical latanoprost in Indian eyes. DESIGN Prospective non-randomised open-label multicentric trial. METHODS One hundred and fifty patients with ocular hypertension (OHT), primary open-angle, pseudoexfoliation or pigmentary glaucoma were enrolled at four centers. Each center contributed at least 20 patients. Following baseline measurements, 0.005% latanoprost was applied topically once daily in the evening for three months. Patients were examined at 2, 6 and 12 weeks. The primary outcome measure was mean intraocular pressure (IOP) reduction. The mean diurnal variation of IOP (difference between highest and lowest IOP) at baseline and at 12-weeks was compared. RESULTS One hundred and thirty of 150 enrolled patients completed the study. One randomly selected eye of each patient was included for analysis. At three months, latanoprost reduced the mean IOP from 24.9 (+/- 3.16) mmHg at baseline to 16.10 (+/- 2.7) mmHg, a reduction of 35.25%. 83% had a reduction in IOP of > 25%. The IOP reduction was maintained throughout the study period, and was not affected by gender or age of the patient. One eye did not show any response to the drug. Daytime diurnal variation of IOP was reduced from 4.5 to 2.9 mmHg. 20 patients had conjunctival hyperemia. Six patients had side effects requiring withdrawal from the study. CONCLUSIONS In this short-term multicentric study, latanoprost effectively reduced IOP and stabilised the diurnal curve in Indian eyes. There were no clinically significant ocular or systemic adverse effects.
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Affiliation(s)
- Ravi Thomas
- L V Prasad Eye Institute, L V Prasad Marg, Banjara Hills, Hyderabad 500-034, India.
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Baskaran M, Rao SK, Ramana Kumar PJ, Vijaya L, Madhavan HN. Postphacoemulsification endophthalmitis--role of residual debris in the handsets used for surgery. Eye (Lond) 2005; 19:115-6. [PMID: 15094717 DOI: 10.1038/sj.eye.6701484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Arvind H, George R, Baskaran M, Raju P, Ramesh SV, Paul PG, Vijaya L. Effect of cataract surgery with intraocular lens implant on frequency doubling perimetry. Curr Eye Res 2005; 30:123-8. [PMID: 15814470 DOI: 10.1080/02713680490904278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To study the effect of cataract surgery with intraocular lens (IOL) on frequency doubling perimetry (FDP). METHODS Patients aged 40 years or above seen at our outpatient clinic with no ocular pathology except for visually significant cataract and visual acuity 6/24 or better were eligible. They underwent FDP before and 4 to 6 weeks after cataract surgery with IOL. RESULTS Screening test: Mean scores by three different scoring methods were 1.82 (3.21), 2.80 (5.54), 4.18 (9.18) before and 0.22 (0.51), 0.26 (0.63), 0.26 (0.69) after surgery (p = 0.002 0.001, < 0.0001). Threshold test: Mean deviation (MD) and pattern standard deviation (PSD) were -5.23 (3.08) and 5.15 (2.78) before and -2.94 [corrected] (2.49) (p < 0.0001) and 5.21 (1.780) (p = 0.63) after surgery. CONCLUSIONS The screening test should be interpreted cautiously in the presence of cataract. On threshold testing, cataract surgery causes significant decrease in MD but no change in PSD.
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Garver E, Baskaran M. Effects of heating on the emanation rates of radon-222 from a suite of natural minerals. Appl Radiat Isot 2004; 61:1477-85. [PMID: 15388150 DOI: 10.1016/j.apradiso.2004.03.107] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Accepted: 03/09/2004] [Indexed: 10/26/2022]
Abstract
The emanating power of radon provides information on the internal structure of a mineral and the radiation damage caused by the decay of 238U, 235U and 232Th (and their daughters) that are present in the mineral. The concentration of 222Rn in groundwater is primarily controlled by the concentration of U and Th in the underlying rocks, as well as the emanation coefficient for that particular rock. The variations in the emanation coefficient for 222Rn caused when subsurface rocks are subjected to tectonic forces results in changes in 222Rn in groundwater. Increased emanation rates of radon from a mineral grain can potentially alter the 238U-206Pb, 235U-207Pb and 232Th-208Pb chronological clocks. We have measured radon emanation coefficients on a suite of minerals comprised of one oxide (uraninite), three silicates (thorite, zircon, and cerite) and one phosphate (monazite) at room temperature and after heating at 200 degrees C and 600 degrees C. Annealing of some of the nuclear tracks within a mineral significantly reduces the emanation rates of radon in these minerals, suggesting that the tracks created by decay events serve as conduit pathways for the release of 222Rn. Higher emanation rates of 222Rn from mineral grains that are surrounded by liquid as compared to air indicate that a major portion of the escaping 222Rn in air gets embedded into adjacent mineral grains and/or opposite walls of a pore.
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Affiliation(s)
- E Garver
- Department of Geology, Wayne State University, 0224 Old Main BLDG, Detroit, MI 48202, USA
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Gunvant P, Baskaran M, Vijaya L, Joseph IS, Watkins RJ, Nallapothula M, Broadway DC, O'Leary DJ. Effect of corneal parameters on measurements using the pulsatile ocular blood flow tonograph and Goldmann applanation tonometer. Br J Ophthalmol 2004; 88:518-22. [PMID: 15031169 PMCID: PMC1772116 DOI: 10.1136/bjo.2003.019331] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To investigate the effect of central corneal thickness and corneal curvature on intraocular pressure measurements using the pulsatile ocular blood flow tonograph and the Goldmann applanation tonometer, and to assess the agreement between the pulsatile ocular blood flow tonograph and the Goldmann applanation tonometer in intraocular pressure measurement. METHODS 479 subjects underwent intraocular pressure measurements with the Goldmann applanation tonometer and the pulsatile ocular blood flow tonograph. Of these, 334 patients underwent additional measurement of central corneal thickness with an ultrasonic pachymeter and corneal curvature measurement with a keratometer. RESULTS The intraocular pressure measurements obtained with both the Goldmann applanation tonometer and the pulsatile ocular blood flow tonograph varied with central corneal thickness and mean keratometric reading. Intraocular pressure measured using the Goldmann applanation tonometer increased by 0.027 mm Hg per micro m increase in central corneal thickness. Intraocular pressure measured using the pulsatile ocular blood flow tonograph increased by 0.048 mm Hg per micro m increase in central corneal thickness. For an increase of 1 mm of mean corneal curvature there was rise in intraocular pressure of 1.14 mm Hg measured by the Goldmann applanation tonometer and of 2.6 mm Hg measured by the pulsatile ocular blood flow tonograph. When compared to the Goldmann applanation tonometer, the pulsatile ocular blood flow tonograph underestimated at low intraocular pressure and overestimated at higher intraocular pressure. CONCLUSION Central corneal thickness and corneal curvature affected measurements obtained with the pulsatile ocular blood flow tonograph more than they affected measurements obtained with the Goldmann applanation tonometer.
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Affiliation(s)
- P Gunvant
- Vision Science Group, Department of Psychological and Brain Science, University of Louisville, KY 40292, USA
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Rao SK, Baskaran M, Kumar PJR, Vijaya L, Madhavan HN. Debris in phacoemulsification handsets. A potential cause of endophthalmitis after cataract surgery? Indian J Ophthalmol 2004; 52:80-1. [PMID: 15132390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
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Abstract
AIM To study the profile of pseudoexfoliation in a population based study. METHOD 2850 consecutive subjects aged 40 years or older from a population based survey in a rural area of southern India underwent complete ophthalmic evaluation including history, visual acuity testing, refraction, slit lamp examination, applanation tonometry, gonioscopy, and dilated examination of the lens (including LOCS II grading of cataract), fundus, and optic disc. Patients with pseudoexfoliation syndrome were identified and their data were analysed with respect to age, sex, intraocular pressure, gonioscopic grading, cataract, and optic neuropathy. RESULTS 108 subjects had pseudoexfoliation syndrome (3.8 %). There was a significant increase in prevalence with age but no sex predilection. The condition was unilateral in 53 cases (49.1%) and bilateral in 55 cases (50.9%). 18 cases with pseudoexfoliation (16.7%) had high intraocular pressure (>21 mm Hg), 16 cases (14.8%) had occludable angles, and 14 cases (13%) had pseudoexfoliation glaucoma. There was a significantly higher prevalence of cataract among people with pseudoexfoliation compared to those without pseudoexfoliation (p = 0.014). CONCLUSION The prevalence of pseudoexfoliation syndrome in the rural population of south India was 3.8%. Raised intraocular pressure was seen in 16.7% of people with pseudoexfoliation and glaucoma was present in 13%.
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Affiliation(s)
- H Arvind
- Sankara Nethralaya, Medical and Vision Research, 18 College Road, Chennai, TN, 600006, India
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Arvind H, Paul PG, Raju P, Baskaran M, George R, Balu S, Sripriya S, Ramesh SV, Mukesh BN, Vijaya L, Kumaramanickavel G, McCarty C. Methods and design of the Chennai Glaucoma Study. Ophthalmic Epidemiol 2004; 10:337-48. [PMID: 14566635 DOI: 10.1076/opep.10.5.337.17320] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE To describe the methodology of a population-based study to estimate the prevalence of glaucoma in a rural and urban South Indian population and to study the genetics of glaucoma in this population. METHODS A sample size of 4758 each for rural and urban populations in the Indian state of Tamil Nadu was calculated. Eligible subjects aged 40 years and above from the rural study area covering 32 contiguous villages and the urban area comprising five random clusters in Chennai city are enumerated. Demographic data are collected in the field. A detailed clinical examination, including glaucoma diagnostic procedures, is conducted at the examination centre. Pedigree ascertainment and genetic studies are performed for subjects with occludable angles or glaucoma. Data are recorded in a computerised database. CONCLUSIONS This study is expected to result in an estimation of the prevalence and a better understanding of the genetics of glaucoma in this region.
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Affiliation(s)
- Hemamalini Arvind
- Glaucoma Project, Vision Research Foundation, Chennai, Sankara Nethralaya, India
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George R, Paul PG, Baskaran M, Ramesh SV, Raju P, Arvind H, McCarty C, Vijaya L. Ocular biometry in occludable angles and angle closure glaucoma: a population based survey. Br J Ophthalmol 2003; 87:399-402. [PMID: 12642298 PMCID: PMC1771625 DOI: 10.1136/bjo.87.4.399] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To compare ocular biometric values in a population based sample of eyes with occludable angles, angle closure glaucoma, and normal subjects. METHOD 2850 subjects from a population based glaucoma prevalence study underwent complete ocular examination including indentation gonioscopy. Ocular biometry was performed in all subjects classified to have occludable angles (n = 143); angle closure glaucoma (n = 22), and a random subgroup of 419 normal subjects. Ocular biometry readings between the groups were compared and statistically analysed using "t," "z," and Mann-Whitney U tests. RESULTS The mean age among subjects with occludable angles (54.43 (SD 9.53) years) and angle closure glaucoma (57.45 (8.5) years) was significantly higher (p<0.001) than normal subjects (49.95 (9.95) years). Axial length was shorter (p<0.001) in the occludable angle group (22.07 (0.69) mm) compared to the normal group (22.76 (0.78) mm). Anterior chamber depth (ACD) was shallower (p<0.001) among subjects with occludable angles (2.53 (0.26) mm) than normal subjects (3.00 (0.30) mm). Lens thickness (LT) was greater (p<0.001) in people with occludable angles (4.40 (0.53) mm) compared to normal subjects (4.31 (0.31) mm). No significant difference was noted in axial length, ACD (p = 0.451), and LT (p = 0.302) between angle closure glaucoma and occludable eyes. CONCLUSION South Indian eyes with angle closure glaucoma and occludable angles seem to have significantly shorter axial lengths, shallower anterior chambers and greater lens thickness compared to the normal group.
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Affiliation(s)
- R George
- Glaucoma Project, Vision Research Foundation, Sankara Nethralaya, Chennai, India Marshfield Medical Research Foundation, WI, USA
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Baskaran M, Hong GH, Dayton S, Bodkin JL, Kelley JJ. Temporal variations of natural and anthropogenic radionuclides in sea otter skull tissue in the North Pacific Ocean. J Environ Radioact 2003; 64:1-18. [PMID: 12469767 DOI: 10.1016/s0265-931x(02)00036-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Marine mammals being among the top predators in the food web tend to accumulate organic and inorganic contaminants from the environment. The body burden of contaminants in these species could reflect their foods and thus contaminant levels could serve as proxies on the changes of ecosystem. A pilot study was carried out to investigate the possibility of radionuclide leakage at Amchitka using a suite of sea otter (Enhydra lutris) skulls collected near Amchitka nuclear test-sites before (1950s) and after the testing (1990s), and at Adak, another Aleutian Island, about 300 km from Amchitka, where the potential impact of radionuclide leakage from Amchitka is expected to be negligible. In addition, the naturally occurring and anthropogenic radionuclide content on the sea otter skull was also utilized to investigate if there was any significant ecosystem changes in the environment. Concentration of 210Pb in sea otter bones collected during the 1950s was significantly higher than those collected in the 1990s. We propose that among the various factors that could cause this higher enrichment in 210Pb, changes in the sea otter prey is the most likely one. Comparison of the 137Cs, 90Sr, 239,240Pu concentrations appear not to be significantly higher in sea otter skulls collected in 1990s from Amchitka where the underground tests in 1965-71 than those from Adak, although significant differences were detected among different groups collected at various times.
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Affiliation(s)
- M Baskaran
- Department of Geology, Wayne State University, Detroit, MI 48202, USA.
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Gunvant P, Joseph IS, Baskaran M, Vijaya L, Broadway DC, Watkins RJ. Pulsatile ocular blood flow measurements in healthy Asian eyes: reference values for an Indian population. Ophthalmic Physiol Opt 2002. [DOI: 10.1046/j.1475-1313.2002.00086_10.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Krishnamurthy RV, Machavaram M, Baskaran M, Brooks JM, Champs MA. Organic carbon flow in the Ob, Yenisey Rivers and Kara Sea of the Arctic region. Mar Pollut Bull 2001; 42:726-732. [PMID: 11585064 DOI: 10.1016/s0025-326x(00)00202-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Stable carbon isotope and elemental C/N ratios of the organic fraction of a set of samples along a transect in the Ob and Yenisey Rivers into the Kara Sea in the Arctic were measured. Previously, the concentrations of 239,240Pu and 137Cs in these same samples had been determined. The coupled measurements were carried out to assess possible connectivity between organic carbon flow into the Kara Sea and transport of radioactive nuclides in this marine environment. Organic carbon flow into the Kara Sea is influenced significantly by terrigenous sources carried by the Ob and Yenisey Rivers. The carbon isotope-organic carbon relationship provides evidence that a rich source of terrigenous carbon exists in the riverine system. A weak, but significant relationship between stable carbon isotope ratio and 137Cs suggests that most of the 137Cs is derived from riverine particles, as compared to Pu which is also derived from in situ scavenging within the water column.
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Affiliation(s)
- R V Krishnamurthy
- Department of Geology, Western Michigan University, Kalamazoo 49008, USA
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Santschi PH, Presley BJ, Wade TL, Garcia-Romero B, Baskaran M. Historical contamination of PAHs, PCBs, DDTs, and heavy metals in Mississippi River Delta, Galveston Bay and Tampa Bay sediment cores. Mar Environ Res 2001; 52:51-79. [PMID: 11488356 DOI: 10.1016/s0141-1136(00)00260-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Profiles of trace contaminant concentrations in sediment columns can be a natural archive from which pollutant inputs into coastal areas can be reconstructed. Reconstruction of historical inputs of anthropogenic chemicals is important for improving management strategies and evaluating the success of recent pollution controls measures. Here we report a reconstruction of historical contamination into three coastal sites along the US Gulf Coast: Mississippi River Delta, Galveston Bay and Tampa Bay. Within the watersheds of these areas are extensive agricultural lands as well as more than 50% of the chemical and refinery capacity of the USA. Despite this pollution potential, relatively low concentrations of trace metals and trace organic contaminants were found in one core from each of the three sites. Concentrations and fluxes of most trace metals found in surface sediments at these three sites, when normalized to Al, are typical for uncontaminated Gulf Coast sediments. Hydrophobic trace organic contaminants that are anthropogenic (polycyclic aromatic hydrocarbons, DDTs, and polychlorinated biphenyls) are found in sediments from all locations. The presence in surface sediments from the Mississippi River Delta of low level trace contaminants such as DDTs, which were banned in the early 1970's, indicate that they are still washed out from cultivated soils. It appears that the DDTs profile in that sediment core was produced by a combination of erosion processes of riverine and other sedimentary deposits during floods. Most of the pollutant profiles indicate that present-day conditions have improved from the more contaminated conditions in the 1950-1970's, before the advent of the Clean Water Act.
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Affiliation(s)
- P H Santschi
- Texas A&M University, Department of Oceanography, Galveston 77551, USA.
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Baskaran M. Scavenging of thorium isotopes in the Arctic regions: implications for the fate of particle-reactive pollutants. Mar Pollut Bull 2001; 42:16-22. [PMID: 11382979 DOI: 10.1016/s0025-326x(00)00194-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The sources of inorganic pollutants to the Arctic areas are reviewed using previously published results. The removal of particle-reactive pollutants is discussed using thorium scavenging as an analog. The scavenging of 234Th from the upper water column (approximately 100 m) and sediment inventory of 230Th from the deep Arctic waters is compared to different ocean basins in the subarctic areas. Such a comparison shows that 234Th is in equilibrium with its parent, 238U, in certain regions of the Canada Basin of the Arctic Ocean, while it is deficient in other regions of the arctic as well as in sub-polar ocean basins. This implies that the particle-reactive pollutants in the deep Arctic of the Canada Basin are less likely to be removed from the deep waters and will eventually be transported out of this area. We have utilized the 230Th inventory in sediments from the Arctic area to determine the removal rates of particle-reactive nuclides. The 230Th inventory in the deep Arctic Ocean of the Canada Basin is much lower than the Norwegian Sea and the Fram Strait of the Arctic as well as all other sub-polar world oceans. These observations suggest that any pollutants into the deep Arctic areas of the Canada Basin are less likely to be removed locally and may be transported out of this area. In those areas, the colloidal material could potentially play a major role in the removal of particle-reactive contaminants.
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Affiliation(s)
- M Baskaran
- Department of Geology, Wayne State University, 0224 Old Main Building, Detroit, MI 48202, USA.
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Hong GH, Lee SH, Kim SH, Chung CS, Baskaran M. Sedimentary fluxes of 90Sr, 137Cs, 239,240Pu and 210Pb in the East Sea (Sea of Japan). Sci Total Environ 1999; 237-238:225-40. [PMID: 10568278 DOI: 10.1016/s0048-9697(99)00138-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Sediment cores collected from the deep basins of the East Sea (Sea of Japan) provide an ongoing and historical record of artificial radionuclides contamination into one of the most highly publicized radioactive waste dumping areas in the world ocean. The depth distributions of 90Sr, 137Cs and 239,240Pu in sediment cores were investigated with the aid of 210Pb-derived sediment accumulation and mixing rates in the deep basins of the East Sea (Sea of Japan). Five box core samples were collected from the northern Yamato Ridge, Korea Plateau, Ulleung and Japan Basins below 1000-m depth. Sediment inventories of 137Cs and 239,240Pu are inversely correlated with water depth and linearly correlated with sediment accumulation rates. The inventories of these nuclides are linearly correlated with the accumulation rates of organic carbon in sediments. The 238Pu/239,240Pu activity ratios in sediments are 0.036 +/- 0.009 suggesting that most of the Pu to the study area is derived from the global fallout. The activity ratios of 239,240Pu/137Cs, and 90Sr/137Cs in bottom sediments are much lower than those of global fallout due to the differences of particle affinity and biological uptake of these nuclides. Sediment inventories of 90Sr and 137Cs constitute < 4% of the anticipated inventories from the global fallout, while those of 239,240Pu constitute 30-150% of the anticipated inventories from the global fallout. The residence time of the dissolved 239,240Pu in the study area is estimated to be 200-400 years based on the sediment inventory and/or sediment accumulation rate, and water column inventory.
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Affiliation(s)
- G H Hong
- Korea Ocean Research and Development Institute, Seoul, South Korea.
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Bianchi TS, Baskaran M, DeLord J, Ravichandran M. Carbon Cycling in a Shallow Turbid Estuary of Southeast Texas: The Use of Plant Pigment Biomarkers and Water Quality Parameters. ACTA ACUST UNITED AC 1997. [DOI: 10.2307/1352353] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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