المؤلفون: Khare, Soumya^{1, 1}, Chatterjee, Tanushree², Gupta, Shailendra³, Patel, Ashish¹

المصدر: Research Journal of Pharmacy and Technology 16(9):4143-4147. 2023

المؤلفون: Tian, Haodong, Patel, Ashish, Burgess, Stephen

مصطلحات موضوعية: Statistics - Methodology, Statistics - Applications

الوصف: Mendelian randomization is an instrumental variable method that utilizes genetic information to investigate the causal effect of a modifiable exposure on an outcome. In most cases, the exposure changes over time. Understanding the time-varying causal effect of the exposure can yield detailed insights into mechanistic effects and the potential impact of public health interventions. Recently, a growing number of Mendelian randomization studies have attempted to explore time-varying causal effects. However, the proposed approaches oversimplify temporal information and rely on overly restrictive structural assumptions, limiting their reliability in addressing time-varying causal problems. This paper considers a novel approach to estimate time-varying effects through continuous-time modelling by combining functional principal component analysis and weak-instrument-robust techniques. Our method effectively utilizes available data without making strong structural assumptions and can be applied in general settings where the exposure measurements occur at different timepoints for different individuals. We demonstrate through simulations that our proposed method performs well in estimating time-varying effects and provides reliable inference results when the time-varying effect form is correctly specified. The method could theoretically be used to estimate arbitrarily complex time-varying effects. However, there is a trade-off between model complexity and instrument strength. Estimating complex time-varying effects requires instruments that are unrealistically strong. We illustrate the application of this method in a case study examining the time-varying effects of systolic blood pressure on urea levels.

الوصول الحر: http://arxiv.org/abs/2403.05336Test

المؤلفون: Patel, Ashish, Whittaker, John C., Burgess, Stephen

مصطلحات موضوعية: Statistics - Methodology, Quantitative Biology - Genomics

الوصف: Colocalization analyses assess whether two traits are affected by the same or distinct causal genetic variants in a single gene region. A class of Bayesian colocalization tests are now routinely used in practice; for example, for genetic analyses in drug development pipelines. In this work, we consider an alternative frequentist approach to colocalization testing that examines the proportionality of genetic associations with each trait. The proportional colocalization approach uses markedly different assumptions to Bayesian colocalization tests, and therefore can provide valuable complementary evidence in cases where Bayesian colocalization results are inconclusive or sensitive to priors. We propose a novel conditional test of proportional colocalization, prop-coloc-cond, that aims to account for the uncertainty in variant selection, in order to recover accurate type I error control. The test can be implemented straightforwardly, requiring only summary data on genetic associations. Simulation evidence and an empirical investigation into GLP1R gene expression demonstrates how tests of proportional colocalization can offer important insights in conjunction with Bayesian colocalization tests.

الوصول الحر: http://arxiv.org/abs/2402.12171Test

المؤلفون: Liu, Xiaoxuan, Prasath, Surya, Siddiqui, Iram, Walters, Thomas D, Denson, Lee A, consortium, PROTECT, Hyams, Jeffrey S, Kugathasan, Subra, Griffiths, Anne M, Collins, Margaret H, Baldassano, Robert N, Boyle, Brendan M, Heyman, Melvin B, Leleiko, Neal S, Mack, David, Markowitz, James, Noe, Joshua D, Oliva-Hemker, Maria, Otley, Anthony, Patel, Ashish S, Pfefferkorn, Marian, Rufo, Paul A, Sauer, Cary G, Strople, Jennifer, Sudel, Boris, Wali, Prateek, Ziring, David, Dhaliwal, Jasbir

المصدر: Gastroenterology. 166(5)

مصطلحات موضوعية: Biomedical and Clinical Sciences, Clinical Sciences, PROTECT Consortium, Neurosciences, Paediatrics and Reproductive Medicine, Gastroenterology & Hepatology, Clinical sciences, Nutrition and dietetics

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/2b51s4n2Test

المؤلفون: Jangre, Nilima¹, Sinha, Jitendra^{2, 1}, Sujatha, Gayam¹, Patel, Ashish³

المصدر: International Journal of Data Mining And Emerging Technologies 7(1):16-22. 2017

المؤلفون: Sojasingarayar, Abonia, Patel, Ashish

مصطلحات موضوعية: Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence

الوصف: 3D object detection is vital as it would enable us to capture objects' sizes, orientation, and position in the world. As a result, we would be able to use this 3D detection in real-world applications such as Augmented Reality (AR), self-driving cars, and robotics which perceive the world the same way we do as humans. Monocular 3D Object Detection is the task to draw 3D bounding box around objects in a single 2D RGB image. It is localization task but without any extra information like depth or other sensors or multiple images. Monocular 3D object detection is an important yet challenging task. Beyond the significant progress in image-based 2D object detection, 3D understanding of real-world objects is an open challenge that has not been explored extensively thus far. In addition to the most closely related studies.

الوصول الحر: http://arxiv.org/abs/2212.11804Test

المؤلفون: Modarai, Bijan, Haulon, Stephan, Ainsbury, Elizabeth, Bockler, Dittmar, Vano-Carruana, Eliseo, Dawson, Joseph, Farber, Mark, Van Herzeele, Isabelle, Hertault, Adrien, van Herwaarden, Joost, Patel, Ashish, Wanhainen, Anders, Weiss, Salome, Goncalves, Frederico Bastos, Bjorck, Martin, Chakfe, Nabil, de Borst, Gert J., Coscas, Raphael, Dias, Nuno V., Dick, Florian, Hinchliffe, Robert J., Kakkos, Stavros K., Koncar, Igor B., Kolh, Philippe, Lindholt, Jes S., Trimarchi, Santi, Tulamo, Riikka, Twine, Christopher P., Vermassen, Frank, Bacher, Klaus, Brountzos, Elias, Fanelli, Fabrizio, Domingos, Liliana A. Fidalgo, Gargiulo, Mauro, Mani, Kevin, Mastracci, Tara M., Maurel, Blandine, Morgan, Robert A., Schneider, Peter

المصدر: European Journal of Vascular and Endovascular Surgery. 65(2):171-222

وصف الملف: electronic

الوصول الحر: https://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-217969Test
https://doi.org/10.1016/j.ejvs.2022.09.005Test
https://umu.diva-portal.org/smash/get/diva2:1819673/FULLTEXT01.pdfTest

المؤلفون: Arquam, Md, Patel, Ashish, Nand, Parma

مصطلحات موضوعية: Computer Science - Cryptography and Security

الوصف: The advent of blockchain technology by the Nakamoto group in 2008 has created a new trend on how to deal with various security issues and vulnerabilities. Blockchain systems have gained momentum in various spheres of technology deployment in business organizations. This paper presents a critical literature survey on the security strength of blockchains and security issues associated with blockchain technology deployment. Numerous studies have experimented with the various technical features of blockchain systems across various transaction domains. Findings obtained from the literature survey and thematic content analysis of the existing research studies indicate that blockchain systems provide unique capabilities that support processes and transactions across various sectors with a high level of integrity, transparency, confidentiality, and privacy. However, some loopholes and limitations associated with the deployment and use of blockchains have been highlighted in various studies. The present study cross-examined the security issues of the underlying scientific research evidence.

الوصول الحر: http://arxiv.org/abs/2205.09097Test

المؤلفون: Murea, Mariana, Patel, Ashish, Highland, Benjamin R, Yang, Wesley, Fletcher, Alison J, Kalantar-Zadeh, Kamyar, Dressler, Emily, Russell, Gregory B

المصدر: American Journal of Kidney Diseases. 80(2)

مصطلحات موضوعية: Biomedical and Clinical Sciences, Clinical Sciences, Bioengineering, Assistive Technology, Kidney Disease, Clinical Research, Digestive Diseases, Clinical Trials and Supportive Activities, Evaluation of treatments and therapeutic interventions, 6.1 Pharmaceuticals, Adult, Glomerular Filtration Rate, Humans, Kidney Failure, Chronic, Pilot Projects, Renal Dialysis, Urea, Adherence, HD dose, HD regimen, dialysis modality, dialysis prescription, end-stage renal disease, feasibility, hemodialysis, incident ESRD, incremental, pilot study, renal urea clearance, residual renal function, thrice weekly, twice weekly, Public Health and Health Services, Urology & Nephrology, Clinical sciences

الوصف: Rationale & objectiveThrice-weekly hemodialysis (HD) is the most common treatment modality for kidney failure in the United States. We conducted a pilot study to assess the feasibility and safety of incremental-start HD in patients beginning maintenance HD.Study designPilot study.Setting & participantsAdults with estimated glomerular filtration rate (eGFR) ≥5 mL/min/1.73 m2 and urine volume ≥500 mL/d beginning maintenance HD at 14 outpatient dialysis units.ExposureRandomized allocation (1:1 ratio) to twice-weekly HD and adjuvant pharmacologic therapy for 6 weeks followed by thrice-weekly HD (incremental HD group) or thrice-weekly HD (conventional HD group).OutcomeThe primary outcome was feasibility. Secondary outcomes included changes in urine volume and solute clearance.ResultsOf 77 patients invited to participate, 51 consented to do so, representing 66% of eligible patients. We randomized 23 patients to the incremental HD group and 25 patients to the conventional HD group. Protocol-based loop diuretics, sodium bicarbonate, and patiromer were prescribed to 100%, 39%, and 17% of patients on twice-weekly HD, respectively. At a mean follow-up of 281.9 days, participant adherence was 96% to the HD schedule (22 of 23 and 24 of 25 in the incremental and conventional groups, respectively) and 100% in both groups to serial timed urine collection. The incidence rate ratio for all-cause hospitalization was 0.31 (95% CI, 0.08-1.17); and 7 deaths were recorded (1 in the incremental and 6 in the conventional group). At week 24, the incremental HD group had lower declines in urine volume (a difference of 51.0 [95% CI, -0.7 to 102.8] percentage points) and in the averaged urea and creatinine clearances (a difference of 57.9 [95% CI, -22.6 to 138.4] percentage points).LimitationsSmall sample size, time-limited twice-weekly HD.ConclusionsIt is feasible to enroll patients beginning maintenance HD into a randomized study of incremental-start HD with adjuvant pharmacotherapy who adhere to the study protocol during follow-up. Larger multicenter clinical trials are indicated to determine the efficacy and safety of incremental HD with longer twice-weekly HD periods.FundingFunding was provided by Vifor Inc.Trial registrationRegistered at ClinicalTrials.gov, identifier NCT03740048.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/0cd6c8hvTest

المؤلفون: Batool, Fatima, Patel, Ashish, Gill, Dipender, Burgess, Stephen

مصطلحات موضوعية: Statistics - Methodology

الوصف: When genetic variants in a gene cluster are associated with a disease outcome, the causal pathway from the variants to the outcome can be difficult to disentangle. For example, the chemokine receptor gene cluster contains genetic variants associated with various cytokines. Associations between variants in this cluster and stroke risk may be driven by any of these cytokines. Multivariable Mendelian randomization is an extension of standard univariable Mendelian randomization to estimate the direct effects of related exposures with shared genetic predictors. However, when genetic variants are clustered, a Goldilocks dilemma arises: including too many highly-correlated variants in the analysis can lead to ill-conditioning, but pruning variants too aggressively can lead to imprecise estimates or even lack of identification. We propose multivariable methods that use principal component analysis to reduce many correlated genetic variants into a smaller number of orthogonal components that are used as instrumental variables. We show in simulations that these methods result in more precise estimates that are less sensitive to numerical instability due to both strong correlations and small changes in the input data. We apply the methods to demonstrate the most likely causal risk factor for stroke at the chemokine gene cluster is monocyte chemoattractant protein-1.

الوصول الحر: http://arxiv.org/abs/2109.12361Test