Publications by authors named "Nayar D"

Background: Stimulant use has been associated with an increased risk of stroke, though data on clinical characteristics and exact risk are limited. This retrospective case-control study examines stroke risk in individuals with stimulant use disorder using data from a national U.S.

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  • Biomolecules in living cells experience crowded environments due to high concentrations of cosolutes and macromolecules, affecting their dynamics and structure.
  • This study uses molecular dynamics simulations to analyze how confinement and the presence of cosolutes like urea influence the collapse equilibria of three different model polymers.
  • The findings reveal that confinement usually promotes polymer collapse, but the effects of urea vary: it weakens collapses in hydrophobic polymers while enhancing collapses in hydrophilic ones, leading to complex interactions that impact the stability of biomolecules in cells.
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Accounting for the crowding effects inside a living cell is crucial to obtain a comprehensive view of the biomolecular processes and designing responsive polymer-based materials for biomedical applications. These effects have long been synonymous with the entropic volume exclusion effects. The role of soft, attractive intermolecular interactions remains elusive.

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It is widely accepted that deciphering biomolecular structure and function requires going beyond the single-molecule or single-complex paradigm. The densely packed macromolecules, cosolutes, and metabolites in the living cell impose crowding effects on the biomolecular structure and dynamics that need to be accounted for. Molecular simulations have proven to be a powerful tool to advance the current molecular-level understanding of such a highly concentrated, complex milieu.

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Unlabelled: A substantial percentage of the population remains at risk for cervical cancer due to pre-existing human papillomavirus (HPV) infections, despite prophylactic vaccines. Early diagnosis and treatment are crucial for better disease outcomes. The development of new treatments heavily relies on suitable preclinical model systems.

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Background: Coronavirus disease 2019 (COVID-19) is known to increase the risk of venous thromboembolism (VTE) and arterial thromboembolism (ATE). However, the incidence, predictors, and outcomes of clinical thrombosis for inpatients with COVID-19 are not well known. This study aimed to enhance our understanding of clinical thrombosis in COVID-19, its associated factors, and mortality outcomes.

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Background: Pregnancy in patients with pulmonary hypertension (PH) is associated with a heightened risk of medical complications including right heart failure, pulmonary edema, and arrhythmias. Our study investigated the association between PH and these complications during delivery.

Methods And Results: The National Inpatient Sample was used to identify delivery hospitalizations from 2011 to 2020.

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  • The BIOFIRE Joint Infection (JI) Panel uses multiplex-PCR testing to identify microorganisms in synovial fluid from patients suspected of septic arthritis and prosthetic joint infections.
  • A study over 34 clinical sites in Europe and the Middle East indicated that the JI Panel showed 88.4% agreement in diagnosing septic arthritis and 85% for prosthetic joint infections when compared to traditional synovial fluid cultures.
  • The JI Panel not only detected more positive samples, especially anaerobic bacteria, but also provided results in about one hour, improving patient management and treatment decisions.
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Computing binding affinities is of great importance in drug discovery pipeline and its prediction using advanced machine learning methods still remains a major challenge as the existing datasets and models do not consider the dynamic features of protein-ligand interactions. To this end, we have developed PLAS-20k dataset, an extension of previously developed PLAS-5k, with 97,500 independent simulations on a total of 19,500 different protein-ligand complexes. Our results show good correlation with the available experimental values, performing better than docking scores.

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COronaVIrus Disease-2019 (COVID-19) is associated with a hypercoagulable state. Intracardiac thrombosis is a potentially serious complication but has seldom been evaluated in COVID-19 patients. We assessed the incidence, associated factors, and outcomes of COVID-19 patients with intracardiac thrombosis.

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Understanding the influence of a crowded intracellular environment on the structure and solvation of DNA functionalized gold nanoparticles (ss-DNA AuNP) is necessary for designing applications in nanomedicine. In this study, the effect of single (Gly, Ser, Lys) and mixture of amino acids (Gly+Ser, Gly+Lys, Ser+Lys) at crowded concentrations is examined on the structure of the ss-DNA AuNP using molecular dynamics simulations. Using the structural estimators such as pair correlation functions and ligand shell positional fluctuations, the solvation entropy is estimated.

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Cutaneous Leishmania major infection elicits a rapid T cell response that is insufficient to clear residually infected cells, possibly due to the accumulation of regulatory T cells in healed skin. Here, we used Leishmania-specific TCR transgenic mice as a sensitive tool to characterize parasite-specific effector and immunosuppressive responses in vivo using two-photon microscopy. We show that Leishmania-specific Tregs displayed higher suppressive activity compared to polyclonal Tregs, that was mediated through IL-10 and not through disrupting cell-cell contacts or antigen presentation.

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Radiology has always gone hand-in-hand with technology and artificial intelligence (AI) is not new to the field. While various AI devices and algorithms have already been integrated in the daily clinical practice of radiology, with applications ranging from scheduling patient appointments to detecting and diagnosing certain clinical conditions on imaging, the use of natural language processing and large language model based software have been in discussion for a long time. Algorithms like ChatGPT can help in improving patient outcomes, increasing the efficiency of radiology interpretation, and aiding in the overall workflow of radiologists and here we discuss some of its potential applications.

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  • Malignant Triton Tumors (MTTs) are rare, aggressive tumors often linked to neurofibromatosis type 1, but this case involved a 33-year-old male with no such history.
  • The patient experienced a recurrence of MTT after initial treatment, leading to extensive surgical interventions and complications, including vocal fold paralysis.
  • The case underscores the need for thorough patient evaluation for accurate diagnosis and timely surgery, highlighting the necessity for further research into new therapies for MTTs.
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The intriguing role of the intracellular crowded environment in regulating protein aggregation remains elusive. The convolution of several factors such as the protein sequence-dependence, crowder's shape and size and diverse intermolecular interactions makes it complex to identify systematic trends. One of the ways to simplify the problem is to study a synthetic model for self-assembling proteins.

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Von Hippel-Lindau disease (VHL) is a multisystem cancer syndrome caused by the inactivation of the VHL tumor suppressor gene and involves various organ systems including the central nervous system (CNS), endocrine system, and the kidneys. Tumors seen in patients with VHL disease can be benign or malignant and are usually multifocal, bilateral, and hypervascular in nature. As most lesions associated with VHL are asymptomatic initially, early diagnosis and the institution of an evidence-based surveillance protocol are of paramount importance.

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A comprehensive understanding of protein folding and biomolecular self-assembly in the intracellular environment requires obtaining a microscopic view of the crowding effects. The classical view of crowding explains biomolecular collapse in such an environment in terms of the entropic solvent excluded volume effects subjected to hard-core repulsions exerted by the inert crowders, neglecting their soft chemical interactions. In this study, the effects of nonspecific, soft interactions of molecular crowders in regulating the conformational equilibrium of hydrophilic (charged) polymers are examined.

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A comprehensive understanding of crowding effects on biomolecular processes necessitates investigating the bulk thermodynamic and kinetic properties of the solutions with an accurate molecular representation of the crowded milieu. Recent studies have reparameterized the non-bonded dispersion interaction of solutes to precisely model intermolecular interactions, which would circumvent artificial aggregation as shown by the original force-fields. However, the performance of this reparameterization is yet to be assessed for concentrated crowded solutions in terms of investigating the hydration shell structure, energetics and dynamics.

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Drug design involves the process of identifying and designing molecules that bind well to a given receptor. A vital computational component of this process is the protein-ligand interaction scoring functions that evaluate the binding ability of various molecules or ligands with a given protein receptor binding pocket reasonably accurately. With the publicly available protein-ligand binding affinity data sets in both sequential and structural forms, machine learning methods have gained traction as a top choice for developing such scoring functions.

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  • Septic arthritis is a severe illness often diagnosed through culture, but the recently approved BioFire® Joint Infection Panel (BJIP) offers a rapid alternative using synovial fluid.
  • A study in the UK and Ireland showed that BJIP had a higher detection rate of positive results (98 vs 83) compared to routine cultures, with a positive percent agreement (PPA) of 91.6% and negative percent agreement (NPA) of 93%.
  • The multidisciplinary team (MDT) discussed the BJIP's additional benefits, such as identifying antibiotic resistance and influencing treatment choices, while noting that it should complement standard methods and may have limitations regarding untested organisms.
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Computational methods and recently modern machine learning methods have played a key role in structure-based drug design. Though several benchmarking datasets are available for machine learning applications in virtual screening, accurate prediction of binding affinity for a protein-ligand complex remains a major challenge. New datasets that allow for the development of models for predicting binding affinities better than the state-of-the-art scoring functions are important.

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Migraine headache is a painful, disabling condition afflicting 7% of the population. The long-term effort of coping with a chronic headache disorder predisposes the individual to other psychiatric illnesses, ischemic cerebrovascular disease as well as medicine overuse headache. The use of nonpharmacological methods to reduce the stress and pain associated with headache can improve the overall quality of life and reduce the burden of the disease.

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Quantum dots (QDs), owing to their single atom-like electronic structure due to quantum confinement, are often referred to as artificial atoms. This unique physical property results in the diverse functions exhibited by QDs. A wide array of applications have been achieved by the surface functionalization of QDs, resulting in exceptional optical, antimicrobial, catalytic, cytotoxic and enzyme inhibition properties.

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Understanding the fundamental forces such as hydrophobic interactions in a crowded intracellular environment is necessary to comprehensively decipher the mechanisms of protein folding and biomolecular self-assemblies. The widely accepted entropic depletion view of crowding effects primarily attributes biomolecular compaction to the solvent excluded volume effects exerted by the "inert" crowders, neglecting their soft interactions with the biomolecule. In this study, we examine the effects of chemical nature and soft attractive energy of crowders on the water-mediated hydrophobic interaction between two non-polar neopentane solutes using molecular dynamics simulations.

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