193 research outputs found

    Molecular Dynamics Simulation of Strong Shock Waves Propagating in Dense Deuterium With the Effect of Excited Electrons

    Full text link
    We present a molecular dynamics simulation of shock waves propagating in dense deuterium with the electron force field method [J. T. Su and W. A. Goddard, Phys. Rev. Lett. 99, 185003 (2007)], which explicitly takes the excitation of electrons into consideration. Non-equilibrium features associated with the excitation of electrons are systematically investigated. We show that chemical bonds in D2_2 molecules lead to a more complicated shock wave structure near the shock front, compared with the results of classical molecular dynamics simulation. Charge separation can bring about accumulation of net charges on the large scale, instead of the formation of a localized dipole layer, which might cause extra energy for the shock wave to propagate. In addition, the simulations also display that molecular dissociation at the shock front is the major factor corresponding to the "bump" structure in the principal Hugoniot. These results could help to build a more realistic picture of shock wave propagation in fuel materials commonly used in the inertial confinement fusion

    Dynamics of bond breaking and formation in polyethylene near shock front

    Get PDF
    In a systematic study of shock wave propagating in crystalline polyethylenes using molecular dynamics method and the electron force field (eFF) potential, we show that microscopic structure of shock front is significantly affected by the anisotropy of long carbon chain and the bond breaking and recombination dynamics. However, macroscopic properties measured in Hugoniot experiments, such as compression ratio and shock velocity, are not sensitive to carbon chain anisotropy and bond dynamics. Our work also display that hydrogen molecules are formed when the piston speed is in the region between 10 km/s and 30 km/s. However, carbon-hydrogen pair distribution function does not display an indication of carbon-hydrogen phase segregation

    Delayed Effect of Anisaldehyde on Feeding Behavior and Reproduction of Adult Aedes albopictus (Diptera: Culicidae) 1

    Get PDF
    ABSTRACT Anisaldehyde may be useful as a spatial repellent against Aedes albopictus, and it could play a major role in new repellent technology for mosquito management. This study characterized the delayed effects of anisaldehyde on Ae. albopictus adult host-seeking behavior, feeding behavior, and reproduction. Anisaldehyde was applied as a fumigant (0.25 mg/cm 3 ) during different developmental stages of the mosquito (larvae from 1 st instar to pupation, larvae from 1 st instar to adult emergence, pupae, and two-day-old adults). Except when treated as pupae, the resulting adult females (at 5 days of age) exhibited significantly lower host-seeking capability and lower repeated-feeding rates than untreated females. Anisaldehyde treatments also significantly reduced the number of eggs and hatchability, and this chemical prolonged the gonotrophic cycle and egg development. These results showed that anisaldehyde acted as a spatial repellent, where it not only reduced hostseeking capability, but also greatly reduced vectoring capacity and reproduction potential, which is significant for mosquito control and disease prevention

    Mental health resources and awareness of anxiety and depressive disorders in general hospitals in China

    Get PDF
    Background: Mental health disorders are common in China. There is a lack of knowledge and resources of mental health in China. Objectives: To assess the levels of psychiatric resources and services in general hospitals in China. Methods: Data regarding psychiatric departments, wards and staff were collected from 57 general hospitals in four provinces of China (Hubei, Zhejiang, Heilongjiang and Yunnan) between April 2014 and June 2014. Questionnaires were distributed to 1,200 non-psychiatric clinicians. Results: Among the 57 hospitals, 50 provided mental health services, 36 had mental health wards, and seven had neither mental health clinics nor wards. The median number of mental health clinicians was six per hospital. The median number of specialized nurses was 42 per hospital. A total of 1,152 non-psychiatric clinicians with a career duration of 9.4 ± 8.9 years returned completed questionnaires. Only 6.9% reported a good understanding of the manifestation of anxiety and depressive disorders, 4.5% reported a good understanding of the diagnostic criteria, and 3.8% reported a good understanding of the treatment protocols. Discussion: There is inadequate awareness of anxiety and depressive disorders among non-psychiatric clinicians in general hospitals in China. This awareness/understanding increased with increasing hospital level

    Dynamics of bond breaking and formation in polyethylene near shock front

    Get PDF
    In a systematic study of shock wave propagating in crystalline polyethylenes using molecular dynamics method and the electron force field (eFF) potential, we show that microscopic structure of shock front is significantly affected by the anisotropy of long carbon chain and the bond breaking and recombination dynamics. However, macroscopic properties measured in Hugoniot experiments, such as compression ratio and shock velocity, are not sensitive to carbon chain anisotropy and bond dynamics. Our work also display that hydrogen molecules are formed when the piston speed is in the region between 10 km/s and 30 km/s. However, carbon-hydrogen pair distribution function does not display an indication of carbon-hydrogen phase segregation

    Effects of electroacupuncture on the correlation between serum and central immunity in AD model animals

    Get PDF
    Objective. The goal was to investigate the connection between neuroinflammation in the brain and serum inflammatory markers as Alzheimer's disease progressed. We also sought to determine whether electroacupuncture had an effect on inflammatory markers found in blood and other brain regions. Methods. As an animal model for AD, we used senescence-accelerated mouse prone 8 (SAMP8) mice. To examine the effects and probable mechanism of electroacupuncture, we used HE staining, immunofluorescence staining, western blotting, and enzyme-linked immunosorbent assay. Results. Electroacupuncture therapy protected neurons, significantly downregulated the Iba-1 level in the hippocampus (p value was 0.003), frontal lobe cortex (p value was 0.042), and temporal lobe cortex (p value was 0.013) of the AD animal model, all of which had significantly lower levels of IL-6 (p value was 0.001), IL-1β (p value was 0.001), and TNF-α (p value was 0.001) in their serum. Conclusion. The amounts of IL-6, IL-1β, and TNF-α detected in the serum were strongly linked to the levels discovered in the hippocampus and the frontal lobes of the brain, respectively. A better understanding of the electroacupuncture process as well as the course of Alzheimer's disease and the therapeutic benefits of electroacupuncture may be gained by using biomarkers such as serum inflammatory marker biomarkers

    Pregnancy outcomes in infertile patients with endometrial hyperplasia with or without atypia undergoing in vitro fertilization: the early-follicular long protocol is superior to midluteal long protocol

    Get PDF
    BackgroundAlthough in vitro fertilization (IVF) in infertile patients with endometrial hyperplasia is common after drug treatment, the pregnancy outcomes are often unsatisfactory. Till date, no studies have reported the outcome of patients with endometrial hyperplasia treated using early-follicular long (EL) protocol and midluteal long (ML) protocol.ObjectiveTo evaluate the pregnancy outcomes and disease prognosis of patients with endometrial hyperplasia with or without atypia undergoing IVF treatment with EL protocol or ML protocol.MethodsThis was a retrospective study in university-affiliated reproductive medical center. A total of 138 patients with endometrial hyperplasia undergoing IVF treatment were included to compare the pregnancy outcomes and disease prognosis between EL and ML protocols. We further matched 276 patients with normal endometrium to compare the pregnancy outcomes between patients with endometrial hyperplasia and patients with normal endometrium under different controlled ovarian stimulation (COS) protocol.ResultsIn patients with endometrial hyperplasia, the clinical pregnancy rate (CPR) and live birth rate (LBR) were significantly higher in EL protocol than in ML protocol (61.8% vs. 43.5%, P=0.032; 50.0% vs. 30.6%, P= 0.022). In the ML protocol, patients with endometrial hyperplasia had significantly lower CPR and LBR than those with normal endometrium (43.5% vs. 59.7%, P=0.037; 30.6% vs. 49.2%, P=0.016). While in the EL protocol, they achieved similar CPR and LBR as patients with normal endometrium (61.8% vs. 69.7%, P=0.232; 50.0% vs. 59.9%, P=0.156). In patients with endometrial hyperplasia, COS protocol was an independent factor affecting clinical pregnancy (adjusted odds ratio [OR] 2.479; 95% confidence interval [CI] 1.154-5.327) and live birth (adjusted OR 2.730; 95% CI 1.249-5.966). After 1–10 years of follow-up, no significant difference was found in the recurrence rate of endometrial lesions between both treatment groups.ConclusionsFor patients with endometrial hyperplasia undergoing IVF treatment, the EL protocol is superior to ML protocol, and in the EL protocol, they can achieve similar pregnancy outcomes as patients with normal endometrium

    Characterization of Inter- and Intramolecular Interactions of Amyloid Fibrils by AFM-Based Single-Molecule Force Spectroscopy

    Get PDF
    Amyloids are fibrous protein aggregates defined by shared specific structural features. Abnormal accumulation of amyloid in organs leads to amyloidosis, which results in various neurodegenerative diseases. Atomic force microscopy (AFM) has proven to be an excellent tool investigating amyloids; it has been extensively utilized to characterize its morphology, assembly process, and mechanical properties. This review summarizes studies which applied AFM to detect the inter- and intramolecular interactions of amyloid fibrils and classified the influencing factors of amyloid’s nanomechanics in detail. The characteristics of amyloid fibrils driven by inter- and intramolecular interactions, including various morphologies of amyloid fibrils, self-assembly process, and the aggregating pathway, are described. Successful examples where AFM provided abundant information about inter- and intramolecular interactions of amyloid fibrils in different environments are presented. Direct force measurement of intra- or intermolecular interactions utilizing an AFM-based tool, single-molecular force spectroscopy (SMFS), is introduced. Some mechanical information such as elasticity, adhesiveness, and strength was obtained by stretching amyloid fibrils. This review helps researchers in understanding the mechanism of amyloidogenesis and exploring the properties of amyloid using AFM techniques
    • …
    corecore