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Akbari OA, Shirani E, Saghafian M. Investigating the temperature distribution behavior and flow parameters of argon fluid in a nanochannel with changing dimensions of the obstacle using the molecular dynamics (MD) method. Heliyon 2024; 10:e24065. [PMID: 38298619 PMCID: PMC10827689 DOI: 10.1016/j.heliyon.2024.e24065] [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: 06/23/2023] [Revised: 12/05/2023] [Accepted: 01/03/2024] [Indexed: 02/02/2024] Open
Abstract
This article, examines the flow of argon inside a nanochannel with respect to the molecular dynamics (MD) in the free molecular flow regime using LAMMPS software. The nanochannel is made of copper featuring a square cross-section and obstacles of varying dimensions and values. In this study, the flow of argon fluid is three-dimensional. To gain a deeper understanding of the effect of solid walls within the nanochannel and their influence on flow behavior, the research is simulated in a nanochannel with all side walls for the 3D model and without side walls for the 2D model. This research assesses the effect of the obstacles' dimensions and values on the nanochannel wall surface and areas above the wall surface. The total dimensions of all simulated two- and three-dimensional atomic structures with a square cross-section are assumed to be 60 × 60 × 100 Å3. and the presence of square obstacles (with dimensions of 8 × 8 × 8 Å3) and rectangular obstacles (with dimensions of 8 × 18 × 8 Å3) is examined. This study seeks to understand the influence on flow behavior, temperature distribution, density, heat flux, velocity, and thermal conductivity coefficient. This study is simulated using a time step of 1 fs for 10,000 time steps, involving approximately 10,000-15,000 argon and copper atoms. The results of this research indicate that obstacles with structures of P and R and larger dimensions increase the number of solid atoms exhibiting stronger attractive forces. Compared to a smooth nanochannel, the thermal exchange between fluid and solid atoms results in a density increase of 17.5 % and 17.3 %, respectively. On the other hand, in the 3D nanochannel, the sidewalls of the nanochannel have reduced the effect of the presence of R and P obstacles with larger dimensions, which comparing to a smooth nanochannel, have increased the density by 8.21 % and 7.53 %, respectively. The obstacles with different spatial positions (P and R structures) in the two-dimensional nanochannel cause a rise in the thermal conductivity coefficient. The P structure obstacles have a better effect on the thermal conductivity coefficient in the 2D nanochannel compared to the R structure. In the three-dimensional nanochannel, utilizing smaller obstacles proves to be more effective because it results in better atom distribution or temperature distribution due to increased atomic collisions in the central region compared to the wall regions.
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Affiliation(s)
- Omid Ali Akbari
- Mechanical Engineering Group, Pardis College, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Ebrahim Shirani
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Mohsen Saghafian
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
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Anuschek M, Bawuah P, Zeitler JA. Terahertz time-domain spectroscopy for powder compact porosity and pore shape measurements: An error analysis of the anisotropic bruggeman model. Int J Pharm X 2021; 3:100079. [PMID: 34027385 DOI: 10.1016/j.ijpx.2021.100079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022]
Abstract
Terahertz time-domain spectroscopy (THz-TDS) is a novel technique which has been applied for pore structure analysis and porosity measurements. For this, mainly the anisotropic Bruggeman (AB-EMA) model is applied to correlate the effective refractive index (neff) of a tablet and the porosity as well as to evaluate the pore shape based on the depolarisation factor L. This paper investigates possible error sources of the AB-EMA for THz-TDS based tablet analysis. The effect of absorption and tablet anisotropy – changes of pore shape with porosity and density distribution – have been investigated. The results suggest that high tablet absorption has a negligible effect on the accuracy of the AB-EMA. In regards of tablet anisotropy the accuracy of the porosity determination is not impaired significantly. However, density distribution and variations in the pore shape with porosity resulted in an unreliable extraction of the tablet pore shape. As an extension of the AB-EMA a new concept was introduced to convert the model into bounds for L. This new approach was found useful to investigate tablet pore shape but also the applicability of the AB-EMA for an unknown set of data.
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Key Words
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ϵ
˜
eff
, Effective complex dielectric permittivity
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ϵ
˜
s
, Complex dielectric permittivity of the solid fract
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n
˜
, Complex refractive index
- AB-EMA, Anisotropic Bruggemen model
- API, Active pharmaceutical ingredient
- Anisotropy
- Bruggeman model
- D, Tablet diameter
- Density distribution
- H, Tablet thickness
- Ibu, Ibuprofen formulation
- L, Depolarisation factor
- L1, Depolarisation factor at the lowest porosity
- Lac, Lactose
- Lfit, Estimation of the depolarisation factor based on a fitting model
- Ll/u, Lower/upper bound of the depolarisation factor
- Lmax/min, Maximal/minimal depolarisation factor in the simulation of a tablet set
- M, Tablet mass
- MCC, Microcrystalline cellulose
- Pharmaceutical tablet
- Pore structure
- RMSE, Root-mean squared error
- THz-TDS, Terahertz time-domain spectroscopy
- Terahertz
- a1, Gradient of the depolarisation factor as a function of porosity
- a2, Y-intercept of the depolarisation factor as a function of porosity
- c, Speed of light
- f, Porosity
- f1, Lowest porosity in a set of tablets
- n, Refractive index
- neff, 1, Effective refractive index at the lowest porosity
- neff, Effective refractive index
- neff, l/u, Lower/upper Wiener bound for neff
- neff, l/u, Lower/upper margin for ns
- ns, Intrinsic refractive index of the solid fraction
- ns, c, ns estimated with accounting for absorption
- ns, fit, Estimation of the intrinsic refractive index based on a fitting model
- p, Polar axis of a spheroid, parallel to the wavevector
- q, r, Equatorial axes of a spheroid, perpendicular to the wavevector
- tablename Str, Starch
- αeff, Effective absorption coefficient
- κ, Extinction coefficient
- κeff, Effective extinction coefficient
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Hailemeskel E, Tebeje SK, Behaksra SW, Shumie G, Shitaye G, Keffale M, Chali W, Gashaw A, Ashine T, Drakeley C, Bousema T, Gadisa E, Tadesse FG. The epidemiology and detectability of asymptomatic plasmodium vivax and plasmodium falciparum infections in low, moderate and high transmission settings in Ethiopia. Malar J 2021; 20:59. [PMID: 33482841 PMCID: PMC7821398 DOI: 10.1186/s12936-021-03587-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND As countries move to malaria elimination, detecting and targeting asymptomatic malaria infections might be needed. Here, the epidemiology and detectability of asymptomatic Plasmodium falciparum and Plasmodium vivax infections were investigated in different transmission settings in Ethiopia. METHOD A total of 1093 dried blood spot (DBS) samples were collected from afebrile and apparently healthy individuals across ten study sites in Ethiopia from 2016 to 2020. Of these, 862 were from community and 231 from school based cross-sectional surveys. Malaria infection status was determined by microscopy or rapid diagnostics tests (RDT) and 18S rRNA-based nested PCR (nPCR). The annual parasite index (API) was used to classify endemicity as low (API > 0 and < 5), moderate (API ≥ 5 and < 100) and high transmission (API ≥ 100) and detectability of infections was assessed in these settings. RESULTS In community surveys, the overall prevalence of asymptomatic Plasmodium infections by microscopy/RDT, nPCR and all methods combined was 12.2% (105/860), 21.6% (183/846) and 24.1% (208/862), respectively. The proportion of nPCR positive infections that was detectable by microscopy/RDT was 48.7% (73/150) for P. falciparum and 4.6% (2/44) for P. vivax. Compared to low transmission settings, the likelihood of detecting infections by microscopy/RDT was increased in moderate (Adjusted odds ratio [AOR]: 3.4; 95% confidence interval [95% CI] 1.6-7.2, P = 0.002) and high endemic settings (AOR = 5.1; 95% CI 2.6-9.9, P < 0.001). After adjustment for site and correlation between observations from the same survey, the likelihood of detecting asymptomatic infections by microscopy/RDT (AOR per year increase = 0.95, 95% CI 0.9-1.0, P = 0.013) declined with age. CONCLUSIONS Conventional diagnostics missed nearly half of the asymptomatic Plasmodium reservoir detected by nPCR. The detectability of infections was particularly low in older age groups and low transmission settings. These findings highlight the need for sensitive diagnostic tools to detect the entire parasite reservoir and potential infection transmitters.
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Affiliation(s)
- Elifaged Hailemeskel
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
- Department of Biomedical Sciences, College of Natural and Computational Sciences, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia
- Department of Biology, College of Natural and Computational Sciences, Wollo University, PO Box, 1145, Dessie, Ethiopia
- Department of Medical Microbiology, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Surafel K Tebeje
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
- Department of Medical Microbiology, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Sinknesh W Behaksra
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Girma Shumie
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Getasew Shitaye
- Department of Biomedical Sciences, School of Medical Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Migbaru Keffale
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Wakweya Chali
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Abrham Gashaw
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Temesgen Ashine
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
| | - Endalamaw Gadisa
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia
| | - Fitsum G Tadesse
- Malaria and Neglected Tropical Diseases Directorate, Armauer Hansen Research Institute, PO Box 1005, Addis Ababa, Ethiopia.
- Department of Medical Microbiology, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.
- Institute of Biotechnology, Addis Ababa University, PO Box, 1176, Addis Ababa, Ethiopia.
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Yu M, Omar C, Weidemann M, Schmidt A, Litster JD, Salman AD. Roller compaction: Infrared thermography as a PAT for monitoring powder flow from feeding to compaction zone. Int J Pharm 2020; 578:119114. [PMID: 32035257 DOI: 10.1016/j.ijpharm.2020.119114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 10/21/2019] [Revised: 01/22/2020] [Accepted: 01/31/2020] [Indexed: 11/18/2022]
Abstract
Roller compaction is a continuous dry granulation process, in which powder is compressed by two counter-rotating rollers. During this process, the powder feeding to the compaction zone has a significant effect on product quality. This work investigates the flow of powder from the feeding zone to the compaction zone using online infrared thermography as Process Analytical Technology (PAT) which is achieved via a specially built cheek plate (side-sealing). The powder undergoes increasing stress from the rollers when it is approaching the minimum gap of the compaction zone, which can be indirectly monitored by measuring the powder temperature. The online monitoring of the powder flow during the roller compaction helps locate the nip region and identify the effect of different roller forces on the temperature of the feeding powder. The results show that the nip region can be identified by analysing the temperature profiles from the feeding to the compaction zone. The increase of roller force results in an increasing slope of the powder temperature profile. In addition, offline X-ray CT measurement results show the increase of density along the feeding to the compaction direction, which is compared with Johanson theory under different roller forces in the roller compaction process.
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Affiliation(s)
- Mingzhe Yu
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
| | - Chalak Omar
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Marcus Weidemann
- Alexanderwerk AG, Remscheid, North Rhine-Westphalia 42857, Germany
| | | | - James D Litster
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Agba D Salman
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
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Abstract
In Part II of this review we consider the very common case of multiple inputs to a measurement process. We derive, using only elementary steps and the basic mathematics covered in Part I, the formula for the propagation of uncertainties from the inputs to the output. The Gaussian density distribution is briefly explained, since an understanding of this distribution is needed for the determination of so-called expanded uncertainties at the end of a measurement process. The propagation formula in general involves correlations among the inputs, although in many cases these correlations can be considered negligible. Correlations, however, need to be taken into account in related matters such as line-fitting and have particular relevance to method comparisons. These topics are addressed briefly. We next discuss the important question of bias and its incorporation into the expression of uncertainty. We present, finally, six real-world cases in clinical chemistry where uncertainty in the estimated value of the measurand is calculated using the propagation formula.
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Affiliation(s)
| | - Ian Farrance
- Discipline of Laboratory Medicine, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
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Deml C, Eichinger M, van Leeuwen WF, Erhart S, Euler SA, Brunner A. Does intra-articular load distribution change after lateral malleolar fractures? An in vivo study comparing operative and non-operative treatment. Injury 2017; 48:854-60. [PMID: 28283180 DOI: 10.1016/j.injury.2017.02.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/28/2017] [Indexed: 02/02/2023]
Abstract
PURPOSE The impact of isolated malleolar fractures on the intra-articular load distribution within the ankle joint has been studied in several biomechanical cadaver studies during the last decades. Recently, computed tomography osteoabsorptiometry (CT-OAM) has been proposed as a valuable tool to assess intra-articular joint load distribution in vivo. The purpose of this retrospective matched pair analysis was to apply CT-OAM to evaluate in vivo changes of talar load distribution after lateral malleolar fractures in patients treated with open anatomic reduction and internal fixation (ORIF) compared to patients treated non-operatively. METHODS Ten matched pairs of patients with isolated lateral malleolar fractures with a maximum fracture dislocation of 3mm and a median follow-up of 42 month were included into the study. Patients were matched for age, gender, and fracture dislocation. Range of ankle motion (ROM), the AOFAS hindfoot score and the Short Form 36 (SF-36) were evaluated. CT-OAM analysis of the injured and the uninjured contralateral ankles were performed. RESULTS Patients treated with ORIF showed a significant lower ROM compared to the uninjured contralateral ankle. No differences were found regarding clinical scores between patients treated by ORIF and those treated non-operatively. CT-OAM analysis showed symmetrical distribution of subchondral bone mineralization in comparison to the uninjured contralateral ankles for both groups of patients. CONCLUSIONS The data of this study suggest that isolated lateral malleolar fractures with fracture gaps up to 3mm are not associated with a change of the tibio-talar joint load distribution in vivo. Therefore, patients with isolated minimally displaced lateral malleolar fractures may achieve good clinical long-term outcome following non-operative treatment. LEVEL OF EVIDENCE Level III, retrospective cohort study.
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Sak M, Duric N, Littrup P, Sherman ME, Gierach GL. Using ultrasound tomography to identify the distributions of density throughout the breast. Proc SPIE Int Soc Opt Eng 2016; 9790. [PMID: 28943704 DOI: 10.1117/12.2217611] [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] [Indexed: 11/14/2022]
Abstract
Women with high breast density are at increased risk of developing breast cancer. Breast density has usually been defined using mammography as the ratio of fibroglandular tissue to total breast area. Ultrasound tomography (UST) is an emerging modality that can also be used to measure breast density. UST creates tomographic sound speed images of the patient's breast which is useful as sound speed is directly proportional to tissue density. Furthermore, the volumetric and quantitative information contained in the sound speed images can be used to describe the distribution of breast density. The work presented here measures the UST sound speed density distributions of 165 women with negative screening mammography. Frequency distributions of the sound speed voxel information were examined for each patient. In a preliminary analysis, the UST sound speed distributions were averaged across patients and grouped by various patient and density-related factors (e.g., age, body mass index, menopausal status, average mammographic breast density). It was found that differences in the distribution of density could be easily visualized for different patient groupings. Furthermore, findings suggest that the shape of the distributions may be used to identify participants with varying amounts of dense and non-dense tissue.
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Affiliation(s)
- Mark Sak
- Delphinus Medical Technologies, 46701 Commerce Center Dr, Plymouth, MI, 48170
| | - Neb Duric
- Delphinus Medical Technologies, 46701 Commerce Center Dr, Plymouth, MI, 48170
| | - Peter Littrup
- Delphinus Medical Technologies, 46701 Commerce Center Dr, Plymouth, MI, 48170.,Brown University, Rhode Island Hospital, 593 Eddy Street, Providence RI, 02903
| | - Mark E Sherman
- Breast and Gynecologic Cancer Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD, USA
| | - Gretchen L Gierach
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
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