Publications by authors named "Purba Chatterjee"

Objective measures of oral PrEP adherence - especially point-of-care (POC) measures that enable real-time assessment, intervention, and feedback - have the potential to improve adherence. Our team previously developed and validated a novel urine-based POC metric of PrEP adherence. In this study, we sought to determine whether this assay is acceptable and feasible among women taking PrEP and PrEP providers in Kenya.

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Organisms that are adapting to long-term environmental change almost always deal with multiple environments and trade-offs that affect their optimal phenotypic strategy. Here, we combine the idea of repeated variation or heterogeneity, like seasonal shifts, with long-term directional dynamics. Using the framework of fitness sets, we determine the dynamics of the optimal phenotype in two competing environments encountered with different frequencies, one of which changes with time.

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Article Synopsis
  • A pilot trial was conducted to evaluate the effectiveness of a new urine assay for monitoring adherence to tenofovir-based PrEP, comparing standard counselling with counselling based on urine test results over a 12-month period.
  • The study enrolled 100 women and found that those receiving urine-test counselling had significantly lower rates of long-term non-adherence to PrEP, with only 21% showing undetectable tenofovir levels compared to 37% in the standard care group.
  • Overall, 72% of women in the urine-test counselling group had detectable tenofovir in urine at the end of the study, indicating improved short-term adherence relative to 45% in the standard care group.*
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Transcription of genes can be affected by both biochemical and mechanical factors. Recent experiments suggested that the mechanical stress associated with transcription-induced DNA supercoiling is responsible for the transition from cooperative to antagonistic group dynamics of RNA polymerases (RNAPs) upon promoter repression. To underpin the mechanism behind this drastic transition, we developed a continuum deterministic model for transcription under torsion.

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In this paper, we develop a field-theoretic description for run and tumble chemotaxis, based on a density-functional description of crystalline materials modified to capture orientational ordering. We show that this framework, with its in-built multiparticle interactions, soft-core repulsion, and elasticity, is ideal for describing continuum collective phases with particle resolution, but on diffusive timescales. We show that our model exhibits particle aggregation in an externally imposed constant attractant field, as is observed for phototactic or thermotactic agents.

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: To ensure the continuity of high-quality HIV care in Kisumu County, Kenya during the corona virus disease 2019 pandemic, the Ministry of Health implemented a strategy to promote physical distancing and corona virus disease 2019 case detection. A total of 23 262 (84.2%) of the 27 641 patients eligible for early refill received an extra 3-month supply of antiretrovirals.

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Background: The worldwide expansion of preexposure prophylaxis (PrEP) with oral tenofovir-disoproxil-fumarate/emtricitabine will be critical to ending the HIV epidemic. However, maintaining daily adherence to PrEP can be difficult, and the accuracy of self-reported adherence is often limited by social desirability bias. Pharmacologic adherence monitoring (measuring drug levels in a biomatrix) has been critical to interpreting PrEP trials, but testing usually requires expensive equipment and skilled personnel.

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Background: Mental disorders are a leading cause of global disability, driven primarily by depression and anxiety. Most of the disease burden is in Low and Middle Income Countries (LMICs), where 75% of adults with mental disorders have no service access. Our research team has worked in western Kenya for nearly ten years.

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A large class of mesoscopic or macroscopic flocking theories are coarse-grained from microscopic models that feature binary interactions as the chief aligning mechanism. However, while such theories seemingly predict the existence of polar order with just binary interactions, actomyosin motility assay experiments show that binary interactions are insufficient to obtain polar order, especially at high densities. To resolve this paradox, here we introduce a solvable one-dimensional flocking model and derive its stochastic hydrodynamics.

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Ruviprase, a 4.4 kDa peptide isolated from Daboia russelii russelii venom demonstrated antiproliferative activity against EMT6/AR1, U-87MG, HeLa and MCF-7 cancer cells with an IC50 value of 23.0, 8.

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