Influence of Number and Strength of Hydrogen Bonds on Fracture Property and Microscopic Mechanisms of Associative Hydrogen-Bonded Polymers via Molecular Dynamics Simulation.

A coarse-grained model combining the acceptor-hydrogen-donor 3-body potential is first developed in this work to explore the fracture property and microscopic mechanisms of associative hydrogen-bonded polymers (AHBPs). Next, a triaxial deformation mode is performed to reveal that the fracture toughness of AHBPs initially improves and then is reduced as the number of active groups increases. By characterizing the stress decomposition, the strong hydrogen bond (HB) network improves the maximum stress but reduces the elongation.

Bio-Based Polyurethane Composites with Adjustable Fluorescence and Ultraviolet Shielding for Anti-Counterfeiting and Ultraviolet Protection.

Polyurethane and its composites play an important role in innovative packing materials including anticounterfeiting and ultraviolet protection, however, they are mainly derived from petroleum resources that are not sustainable. In this study, a 100% biobased thermoplastic polyurethane (Bio-TPU) was synthesized using biobased poly(trimethylene ether) glycol, pentamethylene disocyanate, and 1,4-butanediol. Subsequently, biobased tannic acid (TA) was employed to prepare biobased composites.

Performance of the Flash10 COVID-19 point-of-care molecular test.

After the COVID-19 pandemic, fever clinics urgently require rapid nucleic acid tests to enhance their capacity for timely pathogen detection. This study evaluated the analytical performance and clinical utility of the Flash10 SARS-CoV-2 point-of-care test (Flash10 POCT) for detecting SARS-CoV-2 in patients with fever in the adult fever clinic in Beijing Tsinghua Changgung Hospital from August 1 to August 30, 2023. The analytical performance and clinical utility of the Flash10 POCT for detecting SARS-CoV-2 were assessed in 125 patients with fever syndrome in the adult fever clinic.

Clinical Identification of Two Novel -like Species Isolated as Pathogens of Granulomatous Lobular Mastitis.

Granulomatous lobular mastitis (GLM) is a rare benign breast inflammatory disease that affects women of childbearing age. species, especially , was reported as the pathogen of GLM. A recent study showed that the complex is composed of and two novel species, and .

Investigating the Effect of Chain Extender on the Phase Separation and Mechanical Properties of Polybutadiene-Based Polyurethane.

The thermodynamic incompatibility between the soft and hard segments of thermoplastic polyurethane (TPU) results in a microphase-separated behavior and excellent mechanical properties. However, the effect of the chain extender on the degree of microphase separation (DMS) and the resultant mechanical properties of TPU have not been well studied because of the complex interactions between the soft and hard segments. Herein, hydroxyl-terminated polybutadiene-based TPUs(HTPB-TPUs) without hydrogen bonding between the soft and hard segments are synthesized using hydroxyl-terminated polybutadiene, toluene diisocyanate, and four different chain extenders, and the effect of the chain extender structure on DMS is analyzed experimentally using a combination of analytical techniques.

Thermal Conductivity of the Graphene/Polydimethylsiloxane Composite by Manipulating the Network Structure.

In this work, a nonequilibrium molecular dynamics simulation is utilized to explore the effect of network structure of graphene (GE) on the thermal conductivity of the GE/polydimethylsiloxane (PDMS) composite. First, the thermal conductivity of composites rises with increasing volume fraction of GE. The heat transfer ability via the GE channel is found to be nearly the same by analyzing the GE-GE interfacial thermal resistance (ITR).

Flavonoid as a Potent Antioxidant: Quantitative Structure-Activity Relationship Analysis, Mechanism Study, and Molecular Design by Synergizing Molecular Simulation and Machine Learning.

In this work, a quantitative structure-antioxidant activity relationship of flavonoids was performed using a machine learning (ML) method. To achieve lipid-soluble, highly antioxidant flavonoids, 398 molecular structures with various substitute groups were designed based on the flavonoid skeleton. The hydrogen dissociation energies (Δ, Δ, and Δ) related to multiple hydrogen atom transfer processes and the solubility parameter (δ) of flavonoids were calculated using molecular simulation.

Characterization of viral infections in children with influenza-like-illness during December 2018-January 2019.

Introduction: Respiratory viral infection (RVI) is of very concern after the outbreak of COVID-19, especially in pediatric departments. Learning pathogen spectrum of RVI in children previous the epidemic of COVID-19 could provide another perspective for understanding RVI under current situation and help to prepare for the post COVID-19 infection control.

Methods: A nucleic acid sequence-based amplification (NASBA) assay, with 19 pairs of primers targeting various respiratory viruses, was used for multi-pathogen screening of viral infections in children presenting influenza-like illness (ILI) symptoms.

In-situ self-crosslinking strategy for super-tough polylactic acid/ bio-based polyurethane blends.

As a bio-based degradable plastic, polylactic acid (PLA) is highly commercialized, but its inherent brittleness limits its widespread use. In-situ polymerization techniques are effective in improving the toughness of PLA. However, the enhancement of the toughening effect in polyurethanes (PUs) through in-situ self-crosslinking still requires improvement and heavily relies on petroleum-derived feedstocks in certain approaches.

Screening of Organic Small Molecule Excipients on Ternary Solid Dispersions Based on Miscibility and Hydrogen Bonding Analysis: Experiments and Molecular Simulation.

The preparation of solid dispersions by mixing insoluble drugs with polymers is the main way to improve the aqueous solubility of drugs. The introduction of organic small molecule excipients into binary solid dispersions is expected to further enhance drug solubility by regulating intermolecular hydrogen bonding within the system at the microscopic level. In this study, we used carbamazepine (CBZ) as the target drug and polyvinylpyrrolidone as the solid dispersion matrix and screened the third component from 13 organic small molecules with good miscibility in the solid dispersion based on the principle of similarity of solubility parameters.

Facile Construction of CuFe-Based Metal Phosphides for Synergistic NO Reduction to NH and Zn-Nitrite Batteries in Electrochemical Cell.

The electrocatalytic nitrite/nitrate reduction reaction (eNORR/eNORR) offer a promising route for green ammonia production. The development of low cost, highly selective and long-lasting electrocatalysts for eNORR/eNORR is challenging. Herein, a method is presented for constructing CuP-FeP heterostructures on iron foam (CuFe-P/IF) that facilitates the effective conversion of NO and NO to NH.

[Source Analysis of Ozone and Its Precursors in Zibo Based on 3-D Air Quality Model].

Based on the ISAM module in the WRF-CMAQ model, this study analyzed the source contribution(both regional and sectoral) of O and its precursors(NO and VOCs) in Zibo in June 2021. Days with a maximum daily 8-h average(MDA8) O higher(lower) than 160 μg·m were defined as polluted(clean) days. Differences in the source contribution between clean days and polluted days were compared, and a typical pollution period was selected for further process analysis.

Molecular Dynamics Simulation on the Heat Transfer in the Cross-Linked Poly(dimethylsiloxane).

In this work, the effect of cross-linking degree and stretching on the thermal conductivity of poly(dimethylsiloxane) (PDMS) is explored by performing a molecular dynamics simulation. Our results demonstrate that the thermal conductivity of PDMS exhibits a monotonous rise with an increase in the cross-linking degree. By decomposing the total heat flux into three microscopic heat transfer modes, the high cross-linking degree improves the contribution from bonding interactions to the heat transfer more than that from the nonbonding interactions.

Manipulating the Thermal Conductivity of the Graphene/Poly(vinyl alcohol) Composite via Surface Functionalization: A Multiscale Simulation.

The reverse non-equilibrium molecular dynamics simulation is used to investigate the influence of functional groups (FGs) on the thermal conductivity of a graphene/poly(vinyl alcohol) (PVA) composite, which considers non-polar (methyl) and polar (hydroxyl, amino, and carboxyl) groups. First, the polar groups can be more effective to improve the interfacial thermal conductivity than the non-polar group. This can be explained well by characterizing the interfacial Coulombic energy, number and lifetime of hydrogen bonds, vibrational density of states, and integrated autocorrelation of the interfacial heat power.

Effect of Cross-Linking Density on Non-Linear Viscoelasticity of Vulcanized SBR: A MD Simulation and Experimental Study.

In recent years, there has been a growing interest in changes in dynamic mechanical properties of mixed rubber during dynamic shear, yet the influence of vulcanized characteristics on the dynamic shear behavior of vulcanized rubber, particularly the effect of cross-linking density, has received little attention. This study focuses on styrene-butadiene rubber (SBR) and aims to investigate the impact of different cross-linking densities () on dynamic shear behavior using molecular dynamics (MD) simulations. The results reveal a remarkable Payne effect, where the storage modulus experiences a significant drop when the strain amplitude (γ) exceeds 0.

Mutations obstructing ATP's emplacement in KIF2A nucleotide-binding pocket causes parenchymal malformations, motor developmental delay, with intellectual disability.

Background: KIF2A-related tubulinopathy (MIM: #615411) is a very rare disorder that was clinically characterized as microcephaly, epilepsy, motor developmental disorder (MDD), and various malformations of cortical development, but intellectual disability (ID) or global developmental delay (GDD) was rarely reported in the patients.

Methods: Quad whole-exome sequencing (WES) was performed on the proband, the older brother, and their parents. Sanger sequencing was used to verify the candidate gene variant.

Isolation and Characterization of Pseudomonas aeruginosa Phages with a Broad Host Spectrum from Hospital Sewage Systems and Their Therapeutic Effect in a Mouse Model.

This study aimed to isolate and characterize phages as an alternative treatment of multidrug- or pan-drug-resistant Pseudomonas aeruginosa. Phage titers and bacterial densities correlated, with the phages disappearing after bacteria were eliminated. We isolated phages in filtered sewage water by a double-layered agar spot test.

Analyzing and Predicting the Viscosity of Polymer Nanocomposites in the Conditions of Temperature, Shear Rate, and Nanoparticle Loading with Molecular Dynamics Simulations and Machine Learning.

Predicting the viscosity (η) of polymer nanocomposites (PNCs) is of critical importance as it governs a dominant role in PNCs' processing and application. Machine-learning (ML) algorithms, enabled by pre-existing experimental and computational data, have emerged as robust tools for the prediction of quantitative relationships between feature parameters and various physical properties of materials. In this work, we employed nonequilibrium molecular dynamics (NEMD) simulation with ML models to systematically investigate the η of PNCs over a wide range of nanoparticle (NP) loadings (φ), shear rates (γ̇), and temperatures ().

Fabrication of Polyurethane Elastomer/Hindered Phenol Composites with Tunable Damping Property.

Vibration and noise-reduction materials are indispensable in various fields. Polyurethane (PU)-based damping materials can dissipate the external mechanical and acoustic energy through molecular chain movements to mitigate the adverse effects of vibrations and noise. In this study, PU-based damping composites were obtained by compositing PU rubber prepared using 3-methyltetrahydrofuran/tetrahydrofuran copolyether glycol, 4,4'-diphenylmethane diisocyanate, and trimethylolpropane monoallyl ether as raw materials with hindered phenol, viz.

Genomic Epidemiology of Isolated in a Tertiary Hospital in Beijing, China, from 2018 to 2022.

is one of the most common bacterial pathogens of a wide range of community-acquired infections. It has been more and more recognized that this bacterium could also play a role as a cause of nosocomial infections. In this study, by retrospective analysis of the phenotypic resistance characteristics and genomic characteristics of 52 isolates in a hospital in Beijing, China, from 2018 to 2022, we explored the carriage of resistance genes and mutations in penicillin-binding proteins corresponding to the resistances, and identified the population diversity based on the prediction of serotypes and identification of sequence types (STs).

PI3K polymorphism in patients with sporadic Parkinson's disease.

Parkinson's disease (PD) is a common irreversible neurodegenerative disease associated with cognitive impairment. To investigate the serum level of phosphatidylinositol-3-kinase (PI3K) and the distribution of the genotypes and alleles of 3 PI3K single-nucleotide polymorphisms (RS37,30,087, RS37,30,088, and RS37,30,089) in PD patients with different clinical characteristics. A total of 54 PD patients and 50 healthy individuals were recruited.

Finite Element Solution for Dynamic Mechanical Parameter Influence on Underwater Sound Absorption of Polyurethane-Based Composite.

Underwater noise pollution, mainly emitted by shipping and ocean infrastructure development of human activities, has produced severe environmental impacts on marine species and seabed habitats. In recent years, a polyurethane-based (PU-based) composite with excellent damping performance has been increasingly utilized as underwater sound absorption material by attaching it to equipment surfaces. As one of the key parameters of damping materials, dynamic mechanical parameters are of vital importance to evaluating the viscoelastic damping property and thus influencing the sound absorption performance.

Correction: Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation.

Correction for 'Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation' by Yimin Wang , , 2022, , 4090-4101, https://doi.org/10.1039/D2SM00463A.

Increasing serum antibodies against type B influenza virus in 2017-2018 winter in Beijing, China.

Influenza B virus circulates yearly with lower activity than that of influenza A virus in China. During winter 2017 to 2018, a sharp surge of influenza activity dominated by type B/Yamagata lineage virus caused unprecedented medical burden in Beijing. This research aimed to understand the underlying mechanism for this circulation and prepare for epidemics in the future.