157 research outputs found
Stronger instruments via integer programming in an observational study of late preterm birth outcomes
In an optimal nonbipartite match, a single population is divided into matched
pairs to minimize a total distance within matched pairs. Nonbipartite matching
has been used to strengthen instrumental variables in observational studies of
treatment effects, essentially by forming pairs that are similar in terms of
covariates but very different in the strength of encouragement to accept the
treatment. Optimal nonbipartite matching is typically done using network
optimization techniques that can be quick, running in polynomial time, but
these techniques limit the tools available for matching. Instead, we use
integer programming techniques, thereby obtaining a wealth of new tools not
previously available for nonbipartite matching, including fine and near-fine
balance for several nominal variables, forced near balance on means and optimal
subsetting. We illustrate the methods in our on-going study of outcomes of
late-preterm births in California, that is, births of 34 to 36 weeks of
gestation. Would lengthening the time in the hospital for such births reduce
the frequency of rapid readmissions? A straightforward comparison of babies who
stay for a shorter or longer time would be severely biased, because the
principal reason for a long stay is some serious health problem. We need an
instrument, something inconsequential and haphazard that encourages a shorter
or a longer stay in the hospital. It turns out that babies born at certain
times of day tend to stay overnight once with a shorter length of stay, whereas
babies born at other times of day tend to stay overnight twice with a longer
length of stay, and there is nothing particularly special about a baby who is
born at 11:00 pm.Comment: Published in at http://dx.doi.org/10.1214/12-AOAS582 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
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Introduction to and Screening Visit Results of the Multicenter Pediatric Crohn's Disease Growth Study.
BackgroundStatural growth impairment is more common in males with Crohn's disease (CD). We assessed sex differences in height Z score differences and bone age (BA) Z scores and characterized age of menarche in a novel contemporary cohort of pediatric CD patients undergoing screening for enrollment in the multicenter longitudinal Growth Study.MethodsCrohn's disease patients (females with chronological age [CA] 5 years and older and younger than 14 years; males with CA 6 years and older and younger than 16 years) participated in a screening visit for the Growth Study. Height BA-Z scores are height Z scores calculated based on BA. Height CA-Z scores are height Z scores calculated based on CA. The height Z score difference equals height CA-Z score minus height BA-Z score.ResultsOne hundred seventy-one patients (60% male) qualified for this analysis. Mean CA was 12.2 years. Mean height CA-Z score was -0.4, and mean height BA-Z score was 0.4 in females. Mean height CA-Z score was -0.1, and mean height BA-Z score was 0.2 in males. The absolute value of the mean height Z score difference was significantly greater in females (0.8) than males (0.3; P = 0.005). The mean BA-Z score in females (-1.0) was significantly lower than in males (-0.2; P = 0.002). The median CA at menarche was 13.6 (95% CI, 12.6-14.6) years.ConclusionsOur screening visit data suggest that standardized height gain is lower in males with skeletal maturation and delayed puberty is common in females in CD. We are investigating these findings in the ongoing Growth Study
Photo-damage to Keratinocytes by Quinine Photosensitization under mild Ultraviolet-B Exposure
Simultaneous and sufficient exposure to sunlight and drug cause phototoxic reactions in the skin. In the present study, the photosensitizing activity of quinine (Q) was studied. Evidences obtained by reduction of cell viability, mitochondrial damage, DNA damage, ROS generation, lysosome damage and phosphatidyl serine translocation as a marker of apoptosis indicates that exposure of quinine treated keratinocytes to UV-B radiation results in quinine photosensitization and subsequent reactions which alter normal cellular processes. Quinine absorbs strongly in UV-B region (330 nm). It reduced viability of cells significantly as observed through MTT assay. Reduction of cell viability was confirmed through accumulation of Rhodamine 123 dye which showed that quinine and UV-B treated cells accumulate less than control cells confirmed that mitochondrial membrane potential was disturbed. Increased intracellular ROS production was measured through DCF fluorescence. Early apoptosis was confirmed through phosphatidyl serine translocation in the membrane. Increased lysosome damage was observed through acridine orange accumulation in the lysosmes. Single stranded damage was confirmed through comet assay and apoptosis was confirmed through EB/AO staining. These results show that UV-B radiation elicits phototoxic effects in keratinocytes through reactive oxygen species generation
Application of LANDSAT MSS data in ocean colour sensing
Landsat MSS data off Cochin Coast was analysed ond on attempt made to look in to the relationship between
MSS gray values and concentration of pigment/particulate matter. MSS band 4 and 5 showed the maximum gray
value range as compared to band 6 and 7. A density sliced image of band 4 was generated in the form of
Q color coded image showing the gray levels corresponding to various pigment levels
Clinical Text Summarization: Adapting Large Language Models Can Outperform Human Experts
Sifting through vast textual data and summarizing key information imposes a
substantial burden on how clinicians allocate their time. Although large
language models (LLMs) have shown immense promise in natural language
processing (NLP) tasks, their efficacy across diverse clinical summarization
tasks has not yet been rigorously examined. In this work, we employ domain
adaptation methods on eight LLMs, spanning six datasets and four distinct
summarization tasks: radiology reports, patient questions, progress notes, and
doctor-patient dialogue. Our thorough quantitative assessment reveals
trade-offs between models and adaptation methods in addition to instances where
recent advances in LLMs may not lead to improved results. Further, in a
clinical reader study with six physicians, we depict that summaries from the
best adapted LLM are preferable to human summaries in terms of completeness and
correctness. Our ensuing qualitative analysis delineates mutual challenges
faced by both LLMs and human experts. Lastly, we correlate traditional
quantitative NLP metrics with reader study scores to enhance our understanding
of how these metrics align with physician preferences. Our research marks the
first evidence of LLMs outperforming human experts in clinical text
summarization across multiple tasks. This implies that integrating LLMs into
clinical workflows could alleviate documentation burden, empowering clinicians
to focus more on personalized patient care and other irreplaceable human
aspects of medicine.Comment: 23 pages, 22 figure
Engineering key components in a synthetic eukaryotic signal transduction pathway
Signal transduction underlies how living organisms detect and respond to stimuli. A goal of synthetic biology is to rewire natural signal transduction systems. Bacteria, yeast, and plants sense environmental aspects through conserved histidine kinase (HK) signal transduction systems. HK protein components are typically comprised of multiple, relatively modular, and conserved domains. Phosphate transfer between these components may exhibit considerable cross talk between the otherwise apparently linear pathways, thereby establishing networks that integrate multiple signals. We show that sequence conservation and cross talk can extend across kingdoms and can be exploited to produce a synthetic plant signal transduction system. In response to HK cross talk, heterologously expressed bacterial response regulators, PhoB and OmpR, translocate to the nucleus on HK activation. Using this discovery, combined with modification of PhoB (PhoB-VP64), we produced a key component of a eukaryotic synthetic signal transduction pathway. In response to exogenous cytokinin, PhoB-VP64 translocates to the nucleus, binds a synthetic PlantPho promoter, and activates gene expression. These results show that conserved-signaling components can be used across kingdoms and adapted to produce synthetic eukaryotic signal transduction pathways
A structural biology community assessment of AlphaFold2 applications
Most proteins fold into 3D structures that determine how they function and orchestrate the biological processes of the cell. Recent developments in computational methods for protein structure predictions have reached the accuracy of experimentally determined models. Although this has been independently verified, the implementation of these methods across structural-biology applications remains to be tested. Here, we evaluate the use of AlphaFold2 (AF2) predictions in the study of characteristic structural elements; the impact of missense variants; function and ligand binding site predictions; modeling of interactions; and modeling of experimental structural data. For 11 proteomes, an average of 25% additional residues can be confidently modeled when compared with homology modeling, identifying structural features rarely seen in the Protein Data Bank. AF2-based predictions of protein disorder and complexes surpass dedicated tools, and AF2 models can be used across diverse applications equally well compared with experimentally determined structures, when the confidence metrics are critically considered. In summary, we find that these advances are likely to have a transformative impact in structural biology and broader life-science research
Activity-Based Funding of Hospitals and Its Impact on Mortality, Readmission, Discharge Destination, Severity of Illness, and Volume of Care: A Systematic Review and Meta-Analysis
Background:
Activity-based funding (ABF) of hospitals is a policy intervention intended to re-shape incentives across health systems through the use of diagnosis-related groups. Many countries are adopting or actively promoting ABF. We assessed the effect of ABF on key measures potentially affecting patients and health care systems: mortality (acute and post-acute care); readmission rates; discharge rate to post-acute care following hospitalization; severity of illness; volume of care.
Methods:
We undertook a systematic review and meta-analysis of the worldwide evidence produced since 1980. We included all studies reporting original quantitative data comparing the impact of ABF versus alternative funding systems in acute care settings, regardless of language. We searched 9 electronic databases (OVID MEDLINE, EMBASE, OVID Healthstar, CINAHL, Cochrane CENTRAL, Health Technology Assessment, NHS Economic Evaluation Database, Cochrane Database of Systematic Reviews, and Business Source), hand-searched reference lists, and consulted with experts. Paired reviewers independently screened for eligibility, abstracted data, and assessed study credibility according to a pre-defined scoring system, resolving conflicts by discussion or adjudication.
Results:
Of 16,565 unique citations, 50 US studies and 15 studies from 9 other countries proved eligible (i.e. Australia, Austria, England, Germany, Israel, Italy, Scotland, Sweden, Switzerland). We found consistent and robust differences between ABF and no-ABF in discharge to post-acute care, showing a 24% increase with ABF (pooled relative risk = 1.24, 95% CI 1.18–1.31). Results also suggested a possible increase in readmission with ABF, and an apparent increase in severity of illness, perhaps reflecting differences in diagnostic coding. Although we found no consistent, systematic differences in mortality rates and volume of care, results varied widely across studies, some suggesting appreciable benefits from ABF, and others suggesting deleterious consequences.
Conclusions:
Transitioning to ABF is associated with important policy- and clinically-relevant changes. Evidence suggests substantial increases in admissions to post-acute care following hospitalization, with implications for system capacity and equitable access to care. High variability in results of other outcomes leaves the impact in particular settings uncertain, and may not allow a jurisdiction to predict if ABF would be harmless. Decision-makers considering ABF should plan for likely increases in post-acute care admissions, and be aware of the large uncertainty around impacts on other critical outcomes
Brief report: A reappraisal of clumsiness as a diagnostic feature of Asperger syndrome
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44609/1/10803_2005_Article_BF01046333.pd
PDBe-KB: a community-driven resource for structural and functional annotations.
The Protein Data Bank in Europe-Knowledge Base (PDBe-KB, https://pdbe-kb.org) is a community-driven, collaborative resource for literature-derived, manually curated and computationally predicted structural and functional annotations of macromolecular structure data, contained in the Protein Data Bank (PDB). The goal of PDBe-KB is two-fold: (i) to increase the visibility and reduce the fragmentation of annotations contributed by specialist data resources, and to make these data more findable, accessible, interoperable and reusable (FAIR) and (ii) to place macromolecular structure data in their biological context, thus facilitating their use by the broader scientific community in fundamental and applied research. Here, we describe the guidelines of this collaborative effort, the current status of contributed data, and the PDBe-KB infrastructure, which includes the data exchange format, the deposition system for added value annotations, the distributable database containing the assembled data, and programmatic access endpoints. We also describe a series of novel web-pages-the PDBe-KB aggregated views of structure data-which combine information on macromolecular structures from many PDB entries. We have recently released the first set of pages in this series, which provide an overview of available structural and functional information for a protein of interest, referenced by a UniProtKB accession
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