415 research outputs found
First-principles equation of state and phase stability for the Ni-Al system under high pressures
The equation of state (EOS) of alloys at high pressures is generalized with
the cluster expansion method. It is shown that this provides a more accurate
description. The low temperature EOSs of Ni-Al alloys on FCC and BCC lattices
are obtained with density functional calculations, and the results are in good
agreement with experiments. The merits of the generalized EOS model are
confirmed by comparison with the mixing model. In addition, the FCC phase
diagram of the Ni-Al system is calculated by cluster variation method (CVM)
with both spin-polarized and non-spin-polarized effective cluster interactions
(ECI). The influence of magnetic energy on the phase stability is analyzed. A
long-standing discrepancy between ab initio formation enthalpies and
experimental data is addressed by defining a better reference state. This aids
both evaluation of an ab initio phase diagram and understanding the
thermodynamic behaviors of alloys and compounds. For the first time the
high-pressure behavior of order-disorder transition is investigated by ab
initio calculations. It is found that order-disorder temperatures follow the
Simon melting equation. This may be instructive for experimental and
theoretical research on the effect of an order-disorder transition on shock
Hugoniots.Comment: 27 pages, 12 figure
Retinal Tectonics after Macular Pucker Surgery: Thickness Changes and en Face Displacement Recovery
Purpose: To study visual function, retinal layer thickness changes, and tangential displacement after pars plana vitrectomy for epiretinal membrane.Methods: Retrospective series of patients undergoing pars plana vitrectomy for epiretinal membrane, with 6-month follow-up including best-corrected visual acuity, optical coherence tomography, M-charts, epiretinal membrane grading, and infrared fundus photograph at time 0 (T0, preop) at months 1 (T1), 3 (T3), and 6 (T6) postop (+/- 1 week). Retinal layer thickness and tangential ( en face ) retinal displacement between successive times for the entire retinal surface and the central horizontal and vertical meridian were also measured. En face displacement was calculated as optical flow of consecutive images.Results: Average best-corrected visual acuity improved from 0.28 +/- 0.08 logarithm of Minimum Angle of Resolution at T0 to 0.16 +/- 0.25 at T6 ( P = 0.05), best-corrected visual acuity improvement correlated with best corrected visual acuity (BCVA) at T0 ( P < 0.001). Vertical metamorphopsia decreased from 1.33 degrees +/- 0.70 degrees at T0 to 0.82 degrees +/- 0.69 degrees at T6 ( P < 0.05). Foveal thickness reduced from 453 +/- 53 mu m at T0 to 359 +/- 31 mu m at T6 ( P < 0.05) and reduction correlated with best-corrected visual acuity improvement ( P < 0.05). Foveal layers decreased ( P < 0.05) in all cases. The mean en face deformation was 155.82 +/- 50.17 m and mostly occurred in the first month: T0-T1 displacement was 83.59 +/- 30.28 mu m, T1-T3 was 36.28 +/- 14.45 mu m, while T3-T6 was 39.11 +/- 22.79 mu m ( P < 0.001) on average. Perifoveal and parafoveal deformation correlated with optical coherence tomography foveal thickness reduction at all time intervals (1, 3, and 6 months: P < 0.01).Conclusion: Epiretinal membrane peeling affects all retinal layer thickness and results in new force balance across the entire retina and tangential displacement. Both en face and in-depth changes correlate with visual function
Retinal Tectonics after Macular Pucker Surgery: Thickness Changes and En-Face Displacement Recovery.
PURPOSE
To study visual function, retinal layer thickness changes and tangential displacement after Pars Plana Vitrectomy (PPV) for EpiRetinal Membrane (ERM).
METHODS
Retrospective series of patients undergoing PPV for ERM, with 6-month follow-up including best-corrected visual acuity (BCVA), Optical Coherence Tomography (OCT), M-charts, ERM grading, and InfraRed fundus photo at time 0 (T0, pre-op) at month 1 (T1), 3 (T3), 6 (T6) post-op (±1 week). Retinal layer thickness and tangential (en-face) retinal displacement between successive times for the entire retinal surface and the central horizontal and vertical meridian were also measured. En-face displacement was calculated as optical flow of consecutive images.
RESULTS
Average BCVA improved from 0.28±0.08 logMAR at T0 to 0.16±0.25 at T6 (p=0.05), BCVA improvement correlated with BVCA at T0 (p<0.001). Vertical metamorphopsia decreased from 1.33°±0.70° at T0 to 0.82°±0.69° at T6 (p<0.05). Foveal thickness reduced from 453±53µm at T0 to 359±31µm at T6 (p<0.05) and reduction correlated with BCVA improvement (p<0.05). Foveal layers decreased (p<0.05) in all cases. Mean en-face deformation was 155.82±50.17µm and mostly occurred in the first month: T0-T1 displacement was 83.59±30.28µm, T1-T3 was 36.28±14.45µm, while T3-T6 was 39.11±22.79µm (p<0.001) on average. Peri-foveal and parafoveal deformation correlated with OCT foveal thickness reduction at all time intervals (1, 3, 6 months: p<0.01).
CONCLUSION
ERM peeling affects all retinal layer thickness and results in new force balance across the entire retina and tangential displacement. Both en-face and in-depth changes correlate with visual function
Could Small Neurotoxins-Peptides be Expressed during SARS-CoV-2 Infection?
SARS-CoV-2 pathogenesis has been recently extended to human central nervous system (CNS), in addition to nasopharyngeal truck, eye, lung and gut. The recent literature highlights that some SARS-CoV-2 spike glycoprotein regions homologous to neurotoxin-like peptides might bind to human nicotinic Acetyl-Choline Receptors (nAChRs). Spike-nAChR interaction can probably cause dysregulation of CNS and cholinergic anti-inflammatory pathways and uncontrolled im-mune-response, both associated to a severe COVID-19 pathophysiology. Herein, we hypothesize that inside the Open Reading Frame (ORF) region of spike glycoprotein, the RNA polymerase can translate small neurotoxic peptides by means of a “jumping mechanism” already demonstrated in other coronaviruses. These small peptides can bind the snAChRs instead of Spike glycoproteins. A striking homology occurred between these small peptides observed by sequence retrieval and pro-teins alignment. Acting as nAChRs antagonists, these small peptides (conotoxins) could be the ex-planation for the extrapulmonary clinical manifestations (neurological, hemorrhagic and thrombot-ic expressions, the prolonged apnea, the cardiocirculatory collapse, the heart arrhythmias, the ven-tricular tachycardia, the body temperature alteration, the electrolyte K+ imbalance and finally the significant reduction of butyryl cholinesterase (BuChE) plasma levels, as observed in COVID-19 patients. Several factors might induce the expression of these small peptides, including microbiota. The main hypothesis regarding the presence of these small peptides opens a new scenario on the eti-ology of COVID-19 clinical symptoms observed so far, including the neurological manifestations
Pharmacogenomics and pharmacogenetics: In silico prediction of drug effects in treatments for novel coronavirus SARS-CoV2 disease
The latest developments in precision medicine allow the modulation of therapeutic approaches in different pathologies on the basis of the specific molecular character-ization of the patient. This review of the literature coupled with in silico analysis was to provide a selected screening of interactions between single-nucleotide polymorphisms (SNPs) and drugs (repurposed, investigational, and biological agents) showing efficacy and toxicityin counteracting Covid-19 infection. In silico analysis of genetic variants related to each drug was performed on such databases as PharmGKB, Ensembl Genome Browser, www.drugs.com, and SNPedia, with an extensive literature review of papers (to May 10, 2020) on Covid-19 treatments using Medline, Embase, International Pharmaceutical Abstracts, PharmGKB, and Google Scholar. The clinical relevance of SNPs, known as both drug targets and markers, considering genetic variations with known drug responses, and the therapeutic consequences are discussed. In the context of clinical treatment of Covid-19, including infection prevention, control measures, and supportive care, this review high-lights the importance of a personalized approach in the final selection of therapy, which is probably essential in the management of the Covid-19 pandemic
Artificial intelligence for renal cancer: From imaging to histology and beyond
Artificial intelligence (AI) has made considerable progress within the last decade and is the subject of contemporary literature. This trend is driven by improved computational abilities and increasing amounts of complex data that allow for new approaches in analysis and interpretation. Renal cell carcinoma (RCC) has a rising incidence since most tumors are now detected at an earlier stage due to improved imaging. This creates considerable challenges as approximately 10%–17% of kidney tumors are designated as benign in histopathological evaluation; however, certain co-morbid populations (the obese and elderly) have an increased peri-interventional risk. AI offers an alternative solution by helping to optimize precision and guidance for diagnostic and therapeutic decisions. The narrative review introduced basic principles and provide a comprehensive overview of current AI techniques for RCC. Currently, AI applications can be found in any aspect of RCC management including diagnostics, perioperative care, pathology, and follow-up. Most commonly applied models include neural networks, random forest, support vector machines, and regression. However, for implementation in daily practice, health care providers need to develop a basic understanding and establish interdisciplinary collaborations in order to standardize datasets, define meaningful endpoints, and unify interpretation
A Systematic Review of New Imaging Technologies for Robotic Prostatectomy: From Molecular Imaging to Augmented Reality
New imaging technologies play a pivotal role in the current management of patients with prostate cancer. Robotic assisted radical prostatectomy (RARP) is a standard of care for localized disease and through the already imaging-based console subject of research towards combinations of imaging technologies and RARP as well as their impact on surgical outcomes. Therefore, we aimed to provide a comprehensive analysis of the currently available literature for new imaging technologies for RARP. On 24 January 2023, we performed a systematic review of the current literature on Pubmed, Scopus and Web of Science according to the PRISMA guidelines and Oxford levels of evidence. A total of 46 studies were identified of which 19 studies focus on imaging of the primary tumor, 12 studies on the intraoperative tumor detection of lymph nodes and 15 studies on the training of surgeons. While the feasibility of combined approaches using new imaging technologies including MRI, PSMA-PET CT or intraoperatively applied radioactive and fluorescent dyes has been demonstrated, the prospective confirmation of improvements in surgical outcomes is currently ongoing
A Framework for Human Evaluation of Large Language Models in Healthcare Derived From Literature Review
With generative artificial intelligence (GenAI), particularly large language models (LLMs), continuing to make inroads in healthcare, assessing LLMs with human evaluations is essential to assuring safety and effectiveness. This study reviews existing literature on human evaluation methodologies for LLMs in healthcare across various medical specialties and addresses factors such as evaluation dimensions, sample types and sizes, selection, and recruitment of evaluators, frameworks and metrics, evaluation process, and statistical analysis type. Our literature review of 142 studies shows gaps in reliability, generalizability, and applicability of current human evaluation practices. To overcome such significant obstacles to healthcare LLM developments and deployments, we propose QUEST, a comprehensive and practical framework for human evaluation of LLMs covering three phases of workflow: Planning, Implementation and Adjudication, and Scoring and Review. QUEST is designed with five proposed evaluation principles: Quality of Information, Understanding and Reasoning, Expression Style and Persona, Safety and Harm, and Trust and Confidence
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