168 research outputs found
Dynamic Implicit-Solvent Coarse-Grained Models of Lipid Bilayer Membranes : Fluctuating Hydrodynamics Thermostat
Many coarse-grained models have been developed for equilibrium studies of
lipid bilayer membranes. To achieve in simulations access to length-scales and
time-scales difficult to attain in fully atomistic molecular dynamics, these
coarse-grained models provide a reduced description of the molecular degrees of
freedom and often remove entirely representation of the solvent degrees of
freedom. In such implicit-solvent models the solvent contributions are treated
through effective interaction terms within an effective potential for the free
energy. For investigations of kinetics, Langevin dynamics is often used.
However, for many dynamical processes within bilayers this approach is
insufficient since it neglects important correlations and dynamical
contributions that are missing as a result of the momentum transfer that would
have occurred through the solvent. To address this issue, we introduce a new
thermostat based on fluctuating hydrodynamics for dynamic simulations of
implicit-solvent coarse-grained models. Our approach couples the coarse-grained
degrees of freedom to a stochastic continuum field that accounts for both the
solvent hydrodynamics and thermal fluctuations. We show our approach captures
important correlations in the dynamics of lipid bilayers that are missing in
simulations performed using conventional Langevin dynamics. For both planar
bilayer sheets and bilayer vesicles, we investigate the diffusivity of lipids,
spatial correlations, and lipid flow within the bilayer. The presented
fluctuating hydrodynamics approaches provide a promising way to extend
implicit-solvent coarse-grained lipid models for use in studies of dynamical
processes within bilayers
Alchemical and structural distribution based representation for improved QML
We introduce a representation of any atom in any chemical environment for the
generation of efficient quantum machine learning (QML) models of common
electronic ground-state properties. The representation is based on scaled
distribution functions explicitly accounting for elemental and structural
degrees of freedom. Resulting QML models afford very favorable learning curves
for properties of out-of-sample systems including organic molecules,
non-covalently bonded protein side-chains, (HO)-clusters, as well as
diverse crystals. The elemental components help to lower the learning curves,
and, through interpolation across the periodic table, even enable "alchemical
extrapolation" to covalent bonding between elements not part of training, as
evinced for single, double, and triple bonds among main-group elements
EXPERIMENTAL STUDY ON THE SEISMIC DAMAGE OF AEOLIAN SAND CONCRETE COLUMNS WITH DIFFERENT REINFORCEMENTS
Aeolian sand is a kind of natural material with abundant reserves and a low price. Many scholars have conducted extensive studies on the engineering applications of aeolian sand. This paper addresses the seismic damage behaviour of aeolian sand concrete columns to promote the application of aeolian sand in frame structures. A total of 5 aeolian sand concrete column specimens with different reinforcements were studied using cyclic loading tests. The failure modes, stiffness degradation, bearing capacity, hysteresis peculiarity, ductility, and energy consumption of the specimens were analysed and compared. Then, applicable damage models of the specimens were proposed. The study results prove that the seismic damage behaviour of the specimens increases with the increase of longitudinal reinforcement percentage and with the transverse steel ratio when the replacement percentage of aeolian sand is constant. Additionally, the damage model which is revised in this paper agrees well with the test results. It can be used to assess the degree of damage to the aeolian sand concrete columns
Conjunctival Flap Covering Combined with Antiviral and Steroid Therapy for Severe Herpes Simplex Virus Necrotizing Stromal Keratitis
Herpes simplex virus (HSV) necrotizing stromal keratitis is a common type of herpetic stromal keratitis (HSK). Antiviral medication alone cannot control the disease, and corticosteroid eye drops may aggravate the ulcer and result in corneal perforation. Amniotic membrane transplantation effectively treats superficial corneal ulcer resulting from necrotizing stromal HSK. However, the efficacy of this approach seems to be limited for more serious cases. This study presented the clinical treatment of severe HSV necrotizing stromal keratitis (ulcer depth greater than half of the corneal stroma) by conjunctival flap covering surgery in 25 patients (25 eyes) combined with antivirus and corticosteroid treatment at Shandong Eye Hospital from January 2007 to December 2013. Clinical results showed that the mean best spectacle-corrected visual acuity improved from preoperative 20/333 to postoperative 20/40 (P<0.05). All patients recovered ocular surface stabilization. There was recurrence in two eyes, which was cured with antiviral medication. Conjunctival flap covering combined with antivirus and corticosteroid treatment is effective in treating severe HSV necrotizing stromal keratitis
Tumor microenvironment in pancreatic ductal adenocarcinoma: Implications in immunotherapy
Pancreatic ductal adenocarcinoma is one of the most aggressive and lethal cancers. Surgical resection is the only curable treatment option, but it is available for only a small fraction of patients at the time of diagnosis. With current therapeutic regimens, the average 5-year survival rate is less than 10% in pancreatic cancer patients. Immunotherapy has emerged as one of the most promising treatment options for multiple solid tumors of advanced stage. However, its clinical efficacy is suboptimal in most clinical trials on pancreatic cancer. Current studies have suggested that the tumor microenvironment is likely the underlying barrier affecting immunotherapy drug efficacy in pancreatic cancer. In this review, we discuss the role of the tumor microenvironment in pancreatic cancer and the latest advances in immunotherapy on pancreatic cancer
Eosinophils Instance Object Segmentation on Whole Slide Imaging Using Multi-label Circle Representation
Eosinophilic esophagitis (EoE) is a chronic and relapsing disease
characterized by esophageal inflammation. Symptoms of EoE include difficulty
swallowing, food impaction, and chest pain which significantly impact the
quality of life, resulting in nutritional impairments, social limitations, and
psychological distress. The diagnosis of EoE is typically performed with a
threshold (15 to 20) of eosinophils (Eos) per high-power field (HPF). Since the
current counting process of Eos is a resource-intensive process for human
pathologists, automatic methods are desired. Circle representation has been
shown as a more precise, yet less complicated, representation for automatic
instance cell segmentation such as CircleSnake approach. However, the
CircleSnake was designed as a single-label model, which is not able to deal
with multi-label scenarios. In this paper, we propose the multi-label
CircleSnake model for instance segmentation on Eos. It extends the original
CircleSnake model from a single-label design to a multi-label model, allowing
segmentation of multiple object types. Experimental results illustrate the
CircleSnake model's superiority over the traditional Mask R-CNN model and
DeepSnake model in terms of average precision (AP) in identifying and
segmenting eosinophils, thereby enabling enhanced characterization of EoE. This
automated approach holds promise for streamlining the assessment process and
improving diagnostic accuracy in EoE analysis. The source code has been made
publicly available at https://github.com/yilinliu610730/EoE
Deep Learning-Based Open Source Toolkit for Eosinophil Detection in Pediatric Eosinophilic Esophagitis
Eosinophilic Esophagitis (EoE) is a chronic, immune/antigen-mediated
esophageal disease, characterized by symptoms related to esophageal dysfunction
and histological evidence of eosinophil-dominant inflammation. Owing to the
intricate microscopic representation of EoE in imaging, current methodologies
which depend on manual identification are not only labor-intensive but also
prone to inaccuracies. In this study, we develop an open-source toolkit, named
Open-EoE, to perform end-to-end whole slide image (WSI) level eosinophil (Eos)
detection using one line of command via Docker. Specifically, the toolkit
supports three state-of-the-art deep learning-based object detection models.
Furthermore, Open-EoE further optimizes the performance by implementing an
ensemble learning strategy, and enhancing the precision and reliability of our
results. The experimental results demonstrated that the Open-EoE toolkit can
efficiently detect Eos on a testing set with 289 WSIs. At the widely accepted
threshold of >= 15 Eos per high power field (HPF) for diagnosing EoE, the
Open-EoE achieved an accuracy of 91%, showing decent consistency with
pathologist evaluations. This suggests a promising avenue for integrating
machine learning methodologies into the diagnostic process for EoE. The docker
and source code has been made publicly available at
https://github.com/hrlblab/Open-EoE
Genome-Wide Characterization of Endogenous Retroviruses in Bombyx mori Reveals the Relatives and Activity of env Genes
Endogenous retroviruses (ERVs) are retroviral sequences that remain fixed in the host genome, where they could play an important role. Some ERVs have been identified in insects and proven to have infectious properties. However, no information is available regarding Bombyx mori ERVs (BmERVs) to date. Here, we systematically identified 256 potential BmERVs in the silkworm genome via a whole-genome approach. BmERVs were relatively evenly distributed across each of the chromosomes and accounted for about 25% of the silkworm genome. All BmERVs were classified as young ERVs, with insertion times estimated to be less than 10 million years. Seven BmERVs possessing the env genes were identified. With the exception of the Orf133 Helicoverpa armigera nuclear polyhedrosis virus, the env sequences of BmERVs were distantly related to genes encoding F (Fa and Fb) and GP64 proteins from Group I and Group II NPVs. In addition, only the amino acid sequence of the BmERV-21 envelope protein shared a similar putative furin-like cleavage site and fusion peptide with Group II baculoviruses. All of the env genes in the seven BmERVs were verified to exist in the genome and be expressed in the midgut and fat bodies, which suggest that BmERVs might play an important role in the host biology
Probiotic Lactobacillus rhamnosus GG Induces Alterations in Ileal Microbiota With Associated CD3-CD19-T-bet+IFNγ+/- Cell Subset Homeostasis in Pigs Challenged With Salmonella enterica Serovar 4,[5],12:i:-
Salmonella enterica serovar 4,[5],12:i:- (S. 4,[5],12:i:-) is an emerging foodborne pathogen causing salmonellosis in humans and animals. Probiotic Lactobacillus rhamnosus GG (LGG) is an effective strategy for controlling enteric infections through maintaining gut microbiota homeostasis and regulating the intestinal innate immune response. Here, LGG was orally administrated to newly weaned piglets for 1 week before S. 4,[5],12:i:- challenge. S. 4,[5],12:i:- challenge led to disturbed gut microbiota, characterized by increased levels of Psychrobacter, Chryseobacterium indoltheticum, and uncultured Corynebacteriaceae populations, as well as an aberrant correlation network in Prevotellaceae NK3B31 group-centric species. The beneficial effect of LGG correlated with attenuating the expansion of Prevotellaceae NK3B31 group. Fusobacterium only found in the pigs treated with LGG was positively correlated with Lactobacillus animalis and Propionibacterium. Administration of LGG induced the expansion of CD3-CD19-T-bet+IFNγ+ and CD3-CD19-T-bet+IFNγ- cell subsets in the peripheral blood at 24 h after a challenge of S. 4,[5],12:i:-. S. 4,[5],12:i:- infection increased the population of intraepithelial CD3-CD19-T-bet+IFNγ+ and CD3-CD19-T-bet+IFNγ- cells in the ileum; however, this increase was attenuated via LGG administration. Correlation analysis revealed that LGG enriched Flavobacterium frigidarium and Facklamia populations, which were negatively correlated with intraepithelial CD3-CD19-T-bet+IFNγ+ and CD3-CD19-T-bet+IFNγ- cells in the ileum. The present data suggest that probiotic LGG alters gut microbiota with associated CD3-CD19-T-bet+IFNγ+/- cell subset homeostasis in pigs challenged with S. enterica 4,[5],12:i:-. LGG may be used in potential gut microbiota-targeted therapy regimens to regulate the specific immune cell function and, consequently, control enteric infections
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