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Nicholson JW, Yablon AD, Ramachandran S, Ghalmi S. Spatially and spectrally resolved imaging of modal content in large-mode-area fibers. OPTICS EXPRESS 2008; 16:7233-7243. [PMID: 18545428 DOI: 10.1364/oe.16.007233] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new measurement technique, capable of quantifying the number and type of modes propagating in large-mode-area fibers is both proposed and demonstrated. The measurement is based on both spatially and spectrally resolving the image of the output of the fiber under test. The measurement provides high quality images of the modes that can be used to identify the mode order, while at the same time returning the power levels of the higher-order modes relative to the fundamental mode. Alternatively the data can be used to provide statistics on the level of beam pointing instability and mode shape changes due to random uncontrolled fluctuations of the phases between the coherent modes propagating in the fiber. An added advantage of the measurement is that is requires no prior detailed knowledge of the fiber properties in order to identify the modes and quantify their relative power levels. Because of the coherent nature of the measurement, it is far more sensitive to changes in beam properties due to the mode content in the beam than is the more traditional M(2) measurement for characterizing beam quality. We refer to the measurement as Spatially and Spectrally resolved imaging of mode content in fibers, or more simply as S(2) imaging.
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Ramachandran S, Cherian R. Regional and seasonal variations in aerosol optical characteristics and their frequency distributions over India during 2001–2005. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008560] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Tao L, Ramachandran S, Nelson CT, Lin M, Overzet LJ, Goeckner M, Lee G, Willson CG, Wu W, Hu W. Durable diamond-like carbon templates for UV nanoimprint lithography. NANOTECHNOLOGY 2008; 19:105302. [PMID: 21817695 DOI: 10.1088/0957-4484/19/10/105302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The interaction between resist and template during the separation process after nanoimprint lithography (NIL) can cause the formation of defects and damage to the templates and resist patterns. To alleviate these problems, fluorinated self-assembled monolayers (F-SAMs, i.e. tridecafluoro-1,1,2,2,tetrahydrooctyl trichlorosilane or FDTS) have been employed as template release coatings. However, we find that the FDTS coating undergoes irreversible degradation after only 10 cycles of UV nanoimprint processes with SU-8 resist. The degradation includes a 28% reduction in surface F atoms and significant increases in the surface roughness. In this paper, diamond-like carbon (DLC) films were investigated as an alternative material not only for coating but also for direct fabrication of nanoimprint templates. DLC films deposited on quartz templates in a plasma enhanced chemical vapor deposition system are shown to have better chemical and physical stability than FDTS. After the same 10 cycles of UV nanoimprints, the surface composition as well as the roughness of DLC films were found to be unchanged. The adhesion energy between the DLC surface and SU-8 is found to be smaller than that of FDTS despite the slightly higher total surface energy of DLC. DLC templates with 40 nm features were fabricated using e-beam lithography followed by Cr lift-off and reactive ion etching. UV nanoimprinting using the directly patterned DLC templates in SU-8 resist demonstrates good pattern transfer fidelity and easy template-resist separation. These results indicate that DLC is a promising material for fabricating durable templates for UV nanoimprint lithography.
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Gowri VS, Ramachandran S, Ramesh R, Pramiladevi IRR, Krishnaveni K. Application of GIS in the study of mass transport of pollutants by Adyar and Cooum Rivers in Chennai, Tamilnadu. ENVIRONMENTAL MONITORING AND ASSESSMENT 2008; 138:41-9. [PMID: 17562203 DOI: 10.1007/s10661-007-9789-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 04/06/2007] [Indexed: 05/15/2023]
Abstract
Residential, industrial, commercial, institutional and recreational activities discharge degradable and non-degradable wastes that reach the coastal water through rivers and cause coastal pollution. In the present study, mass transport of pollutants by Adyar and Cooum Rivers to the coastal water as a result of land-based discharges was estimated during low tide. The lowest and the highest flow recorded in Adyar varied from 514.59 to 2,585.08x10(6) litres/day. Similarly, the flow in Cooum River fluctuated between 266.45 and 709.34x10(6) litres/day. The present study revealed that the Adyar River transported 53.89-454.11 t/d of suspended solids, 0.06-19.64 t/d of ammonia, 15.95-123.24 t/d of nitrate and 0.4-17.86 t/d of phosphate, 0.004-0.09 kg/d of cadmium, 0.15-1.29 kg/d of lead and 3.03-17.58 kg/d of zinc to the coastal water owing to its high discharge. Similarly, the Cooum River transported 11.87-120.06 t/d of suspended solids, 0.08-58.7 t/d of ammonia, 6.11-29.25 t/d of nitrate and 0.66-10.73 t/d of phosphate, 0.003-0.021 kg/d of cadmium, 0.02-0.44 kg/d of lead and 1.36-3.87 kg/d of zinc. A higher concentration of suspended solids was noticed in post monsoon and summer months. An increase in the mass transport of ammonia, nitrate, phosphate in summer months (April and May) and an increase in the mass transport of cadmium, lead and zinc were observed in monsoon months (October-December) in both the rivers. Thus mass transport of pollutants study reveal that Cooum and Adyar Rivers in Chennai contribute to coastal pollution by transporting inorganic and trace metals significantly through land drainage.
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Sumetsky M, Ramachandran S. Multiple mode conversion and beam shaping with superimposed long period gratings. OPTICS EXPRESS 2008; 16:402-412. [PMID: 18521172 DOI: 10.1364/oe.16.000402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate how to convert several arbitrary optical fiber modes into a single mode and vice versa using superimposed long period gratings (SLPG). As an example, we theoretically consider SLPG consisting of five gratings, which couple first six LP(0j) modes of a single mode fiber. We optimize the SLPG output to form light beams that are focused at a distance 0.5 mm and 1 mm from the fiber. In addition, we optimize the SLPG output to generate a beam with an amplitude that is uniform inside a 4(0) angle with a +/-0.2 % accuracy. In the latter case, the refractive index profile of the SLPG is calculated for an SMF-28 fiber. The proposed SLPG devices can be used as efficient all-fiber mode focusers and beam shapers.
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Madan Kumar PD, Priya S, Ramachandran S. Knowledge and attitudes of pharmacists regarding oral health care and oral hygiene products in Chennai city. Indian J Dent Res 2008; 19:104-8. [DOI: 10.4103/0970-9290.40462] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Mermelstein MD, Ramachandran S, Fini JM, Ghalmi S. SBS gain efficiency measurements and modeling in a 1714 mum(2) effective area LP(08) higher-order mode optical fiber. OPTICS EXPRESS 2007; 15:15952-15963. [PMID: 19550882 DOI: 10.1364/oe.15.015952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The stimulated Brillouin scattering (SBS) gain efficiencies were measured in the LP(08) and LP(01) modes of a higher-order-mode optical fiber. Gain efficiencies C(B) of 0.0085 and 0.20 (m-W)(-1) were measured for the LP(08) and LP(01) modes at 1083 nm, respectively. C(B) is inversely proportional to the optical effective area Aeff and the same core-localized acoustic phonon seeds the SBS process in each case. An acoustic modal analysis and a distributed phenomenological model are presented to facilitate the data analysis and interpretation. The LP(08) mode exhibits a threshold powerlength product of 2.5 kW-m.
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Ramachandran S, Fernandez F, Patterson A, Mohanakumar T. 44-OR: Activation of the innate immune response by anti-MHC antibodies. Hum Immunol 2007. [DOI: 10.1016/j.humimm.2007.08.239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ramachandran S. Aerosol optical depth and fine mode fraction variations deduced from Moderate Resolution Imaging Spectroradiometer (MODIS) over four urban areas in India. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007jd008500] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Verma S, Venkataraman C, Boucher O, Ramachandran S. Source evaluation of aerosols measured during the Indian Ocean Experiment using combined chemical transport and back trajectory modeling. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007698] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Clifton I, Ramachandran S, Peckham D, Ng L, Robertson R, Moss H, Brownlee K, Conway S. 152 Relationship between HRCT score, lung function and clubbing in patients with cystic fibrosis (CF). J Cyst Fibros 2007. [DOI: 10.1016/s1569-1993(07)60138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Feleppa E, Dasgupta S, Porter C, Ramachandran S, Ketterling J, Kalisz A, Lacrampe M, Isaacson C. SU-FF-I-101: Combining Magnetic-Resonance Spectroscopy and Ultrasound Spectral Parameters to Improve Tissue-Type Imaging of Prostate Cancer. Med Phys 2007. [DOI: 10.1118/1.2760478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Nicholson JW, Ramachandran S, Ghalmi S. A passively-modelocked, Yb-doped, figure-eight, fiber laser utilizing anomalous-dispersion higher-order-mode fiber. OPTICS EXPRESS 2007; 15:6623-6628. [PMID: 19546971 DOI: 10.1364/oe.15.006623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Modelocking in an Yb-doped figure-eight fiber laser is demonstrated utilizing anomalous dispersion from an LP(02) higher-order-mode fiber for dispersion management. Outside the laser cavity, the pulses were re-compressed to 95 fs using a second HOM module, the shortest demonstrated pulses to date from an Yb-doped figure-eight fiber laser. Operation of the laser with HOM fiber in the cavity is compared to an Yb figure-eight laser that utilizes all-normal dispersion fibers.
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Khanna N, Mishra SI, Tian G, Tan MT, Arnold S, Lee C, Ramachandran S, Bell L, Baquet CR, Lorincz A. Human papillomavirus detection in self-collected vaginal specimens and matched clinician-collected cervical specimens. Int J Gynecol Cancer 2007; 17:615-22. [PMID: 17504376 DOI: 10.1111/j.1525-1438.2006.00835.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Human papillomavirus (HPV) detection is an integral part of cervical cancer screening, and a range of specimen collection procedures are being tested. Preliminary studies have found that the majority of women prefer self-collection of vaginal specimens instead of clinician-collected specimens of the cervix. The purposes of the current study were to explore the social and behavioral predictors of acceptance of self-collection of vaginal specimens among patients and to assess concordance in detection of HPV between clinician-collected cervical specimens and self-collected vaginal specimens. The study was conducted at a university family medicine clinic using a cross-sectional study design, and enrollment of women presenting for routine gynecological examination consecutively in a period of 1 year, self-administered questionnaires, collection of paired vaginal and cervical specimens for HPV DNA using Hybrid Capture 2, and cytologic analysis. Most women (79.8% [398/499]) agreed to collect vaginal specimens. In our study, 76.6% (216/282) African American women (AA), 88.1% (156/176) white non-Hispanic (WNH) women, and 63.4% (26/41) women of other races (P < 0.0001) agreed to self-collect vaginal specimens. HPV was detected in 16.0% (80/499) of clinician-collected cervical specimens and 26.1% (104/398) of self-collected vaginal specimens (P < 0.001). HPV detection was concordant in 13.4% (53/398) women in both cervical and vaginal specimens. Self-collection of vaginal specimens for HPV DNA detection is acceptable to most women presenting for routine gynecological examination. WNH women were more likely to obtain self-collected specimens than AA women. Vaginal specimens were more likely to be positive for HPV than were cervical specimens.
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Madan Kumar PD, Poorni S, Ramachandran S. Tobacco use among school children in Chennai city, India. Indian J Cancer 2007; 43:127-31. [PMID: 17065771 DOI: 10.4103/0019-509x.27935] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS The present study was done to build a database on prevalence of tobacco use among students of grade 8 to 10 in Chennai city, for the purpose of advocacy of tobacco control and planning tobacco control interventions and evaluation. MATERIALS AND METHODS A two-stage stratified probability sample of students in grades 8-10 corresponding to 13 to 15 years of age were selected from private/government aided private schools and purely government aided corporation schools. Data was collected by a pretested, closed-ended self-administered questionnaire. RESULTS A total of 1255 students participated in this survey. Among them 64.4 boys and 35.6% were girls. Ever tobacco use was reported by 37.6% of the students (41.6 males and 30.2% females). Current users of tobacco (any products) were reported by 41.1% of the students. Prevalence was more among boy students (46.3%) when compared to that of girl students (31.6%). There existed no significant difference between current users of tobacco based on the zones of the school. Tobacco users prevalence was found more in corporation schools when compared to that of private schools. Parental and friends tobacco use was reported more often by tobacco users compared to never users. Purchasing tobacco products in a store was reported by 82.5% and almost no one was refused because of age. Almost everyone reported watching a lot of cigarette advertisements on TV, whereas about half reported watching advertisements on other medias like outdoor hoardings (45.7%), newspapers (65.3%) and social events (67.4%). CONCLUSION This study demonstrates that among the 13 to 15-year old school going children (corresponding to grades 8 to 10) in Chennai city, the current tobacco use is high.
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Saleem Y, Ramachandran S, Ramamurthy L, Kay NJ. Role of otoacoustic emission in children with middle-ear effusion and grommets. The Journal of Laryngology & Otology 2007; 121:943-6. [PMID: 17419898 DOI: 10.1017/s0022215107007347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/23/2007] [Indexed: 11/07/2022]
Abstract
Objective: To evaluate the role of otoacoustic emission in children with middle-ear effusion and grommets.Materials and methods: A prospective study was carried out on a total of 90 ears. All children listed for grommet insertion had a pre-operative and post-operative (three to six months after grommet insertion) pure tone audiometry, tympanometry and otoacoustic emission recorded. A comparison was made between pure tone audiometry and otoacoustic emission both pre-operatively and post-operatively.Results: Pre-operatively, 63 ears had an abnormal pure tone audiometry of which 59 had absent otoacoustic emission. Therefore the sensitivity of otoacoustic emission in detecting a conductive loss was 59/63 = 94 per cent (95 per cent confidence interval 85 to 98 per cent). All 27 ears with normal hearing pre-operatively had normal otoacoustic emission. The specificity of otoacoustic emission was 27/27 = 100 per cent, (95 per cent confidence interval, 88 to 100 per cent). The positive predictive value was 59/59 = 100 per cent (95 per cent confidence interval, 94 to 100 per cent). After three to six months all post-operative patients with grommets had a normal pure tone audiometry and otoacoustic emission. So both pure tone audiometry and otoacoustic emission were strongly related both in patients with middle-ear effusion and in patients with grommets.Conclusion: As the demonstration of hearing in young and difficult-to-test children can be problematic and time-consuming, we suggest that otoacoustic emission can be used as an alternative to pure tone audiometry in patients with middle-ear effusion and grommets.
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Ramachandran S, Rajesh TA. Black carbon aerosol mass concentrations over Ahmedabad, an urban location in western India: Comparison with urban sites in Asia, Europe, Canada, and the United States. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007488] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ramachandran S, Fontanille P, Pandey A, Larroche C. Spores of Aspergillus niger as reservoir of glucose oxidase synthesized during solid-state fermentation and their use as catalyst in gluconic acid production. Lett Appl Microbiol 2007; 44:155-60. [PMID: 17257254 DOI: 10.1111/j.1472-765x.2006.02051.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To exploit conidiospores of Aspergillus niger as a vector for glucose oxidase extraction from solid media, and their direct use as biocatalyst in the bioconversion of glucose to gluconic acid. METHODS AND RESULTS Spores of A. niger (200 h old) were shown to fully retain all the glucose oxidase synthesized by the mycelium during solid-state fermentation (SSF). They acted as catalyst and carried out the bioconversion reaction effectively, provided they were permeabilized by freezing and thawing. Glucose oxidase activity was found retained in the spores even after repeated washings. Average rate of reaction was 1.5 g l(-1) h(-1) with 102 g l(-1) of gluconic acid produced out of 100 g l(-1) glucose consumed after approx. 100 h reaction, which corresponded to a molar yield close to 93%. These results were obtained with permeabilized spores in the presence of a germination inhibitor, sodium azide. CONCLUSIONS Spores of A. niger served as efficient catalyst in the model bioconversion reaction after permeabilization. SIGNIFICANCE AND IMPACT OF THE STUDY To our knowledge, this is the first detailed study on the ability of A. niger spores to act as reservoir of enzyme synthesized during SSF without its release into solid media. Use of this material served as an innovative concept for enzyme extraction and purification from a solid medium. Moreover, this approach could compete efficiently with the conventional use of mycelial form of the fungus in gluconic acid production.
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Liaw J, Csontos K, Pagliara T, Jia J, Ramachandran S, Mohanakumar T, Chapman W. 113. J Surg Res 2007. [DOI: 10.1016/j.jss.2006.12.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Rukin NJ, Zeegers MP, Ramachandran S, Luscombe CJ, Liu S, Saxby M, Lear J, Strange RC. A comparison of sunlight exposure in men with prostate cancer and basal cell carcinoma. Br J Cancer 2007; 96:523-8. [PMID: 17262085 PMCID: PMC2360028 DOI: 10.1038/sj.bjc.6603576] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ultraviolet radiation exposure increases basal cell carcinoma (BCC) risk, but may be protective against prostate cancer. We attempted to identify exposure patterns that confer reduced prostate cancer risk without increasing that of BCC. We used a questionnaire to assess exposure in 528 prostate cancer patients and 442 men with basal cell carcinoma, using 365 benign prostatic hypertrophy patients as controls. Skin type 1 (odds ratio (OR)=0.47, 95% CI=0.26–0.86), childhood sunburning (OR=0.38, 95% CI=0.26–0.57), occasional/frequent sunbathing (OR=0.21, 95% CI=0.14–0.31), lifetime weekday (OR=0.85, 95% CI=0.80–0.91) and weekend exposure (OR=0.79, 95% CI=0.73–0.86) were associated with reduced prostate cancer risk. Skin type 1 (OR=4.00, 95% CI=2.16–7.41), childhood sunburning (OR=1.91, 95% CI=1.36–2.68), regular foreign holidays (OR=6.91, 95% CI=5.00-9.55) and weekend (OR=1.17, 95% CI=1.08–1.27) but not weekday exposure were linked with increased BCC risk. Combinations of one or two parameters were associated with a progressive decrease in the ORs for prostate cancer risk (OR=0.54–0.25) with correspondingly increased BCC risk (OR=1.60–2.54). Our data do not define exposure patterns that reduce prostate cancer risk without increasing BCC risk.
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Feleppa E, Porter C, Ketterling J, Dasgupta S, Ramachandran S, Sparks D. Recent Advances in Ultrasonic Tissue-Type Imaging of the Prostate. ACOUSTICAL IMAGING 2007. [DOI: 10.1007/1-4020-5721-0_35] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Miglani R, Shankar, Indira R, Ramachandran S. An invitro evaluation of calcium hydroxide root canal sealers and its effect on six microorganisms. J Conserv Dent 2007. [DOI: 10.4103/0972-0707.42269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Shetty C, Balasubramani M, Capps N, Milles J, Ramachandran S. Paradoxical HDL-C reduction during rosiglitazone and fibrate treatment. Diabet Med 2007; 24:94-7. [PMID: 17227331 DOI: 10.1111/j.1464-5491.2007.02029.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS Dyslipidaemia in Type 2 diabetes mellitus (T2DM) is one of the major contributors in the pathogenesis of atherosclerosis. Thiazolidinediones (TZD), a class of drugs used in the treatment of T2DM, also modify lipids, especially lowering serum triglycerides and raising high-density lipoprotein cholesterol (HDL-C). METHODS We describe five patients taking rosiglitazone and a fibrate who showed a paradoxical fall in HDL-C, which would have been missed if HDL-C had not been routinely monitored. This could have had a major impact in increasing the cardiovascular risk in these patients. RESULTS Our five patients showed marked variation in both the decrease in serum HDL-C (50-89%) and also in the time taken for recovery of HDL-C after withdrawal of rosiglitazone (between 5 and 20 weeks). Apolipoprotein A1 mirrored the drop in HDL-C in four of the five patients but in one subject this was not seen, suggesting the possibility of multiple mechanisms leading to the phenomenon described, perhaps involving HDL metabolism. Improvements in glycaemic control with rosiglitazone (absolute HbA(1c) reduction between 0.6 and 3.0%) were seen in four of our patients. This suggests that the peroxisomal proliferator-activated receptor gamma signalling pathways relevant to glucose homeostasis were intact. CONCLUSION As atherosclerosis is associated with a decrease in the HDL-C level, our observations reinforce the message that HDL-C should be measured before and after the commencement of rosiglitazone and also on increasing the dosage
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Nicholson JW, Ramachandran S, Ghalmi S, Yan MF, Wisk P, Monberg E, Dimarcello FV. Propagation of femtosecond pulses in large-mode-area, higher-order-mode fiber. OPTICS LETTERS 2006; 31:3191-3. [PMID: 17041678 DOI: 10.1364/ol.31.003191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We demonstrate propagation of 14 nJ femtosecond pulses through a large-mode-area, higher-order-mode (HOM) fiber with an effective area of 2100 microm2. The pulses propagate stably in the LP07 mode of the fiber through lengths as long as 12 m. The strongly chirped pulses exiting the amplifier fiber are dechirped by the high-order-mode fiber, resulting in pulses with a peak power of 61 kW after propagation in 5 m of the positive-dispersion fiber. A small amount of self-phase modulation is observed in the compressed pulses and is described well by a nonlinear Schrödinger equation model that takes into account the measured effective area and dispersion of the HOM fiber.
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