Quantum solid phase and Coulomb drag in two-dimensional electron-electron bilayers of MoS2

Coulomb drag experiments can give us information about the interaction state of double-layer systems. Here, we demonstrate anomalous Coulomb drag behaviours in a two-dimensional electron-electron bilayer system constructed by stacking atomically thin MoS2 on opposite sides of thin dielectric layers of boron nitride. In the low temperature regime, the measured drag resistance does not follow the behaviour predicted by the Coulomb drag models of exchanging momenta and energies with the particles in Fermi-liquid bilayer systems. Instead, it shows an upturn to higher and higher values. We investigate quantum solid/fluid phases and the Kosterlitz-Thouless/Wigner two-dimensional quantum melting transition in this bilayer system and describe this interesting phenomenon based on thermally activated carriers of quantum defects from the formation of the correlation-induced electron solid phases with enhanced stabilization by the potential due to the boron nitride dielectric layers.Comment: published in Advanced Electronic Material

Start Learning Chinese Words Fast: An Introduction

In order to cater to the needs of Chinese language lovers, 28 basic strokes of Chinese words are firstly introduced. It is pointed out that the difficulty for foreigners to learn Chinese words is their grotesque shapes written by brush (soft) pen and printed in books. The special writing method with a hard pen and 8 directions moving steps are invented and firstly shown, which is easy for foreigners to try. The size (length) of strokes will guide them to control the proportion of a word. It could be changed according to paper size and how large they want to write. Secondly, 48 common fragments derived from 28 basic strokes are listed and the writing method described. It could help foreigners to separate and re-write unknown Chinese words and even guess out the meanings. Lastly, many characteristics or regularities of Chinese words will have great attraction for foreign language learners. Some Chinese cultures or amusing stories are also exposed in fragments and example words

The effect of support surface and footwear condition on postural sway and lower limb muscle action of the older women

Background: Diminished somatosensory function is a critical age-related change which is related to postural instability in the older population. Footwear is a cost-effective way to modulate the postural stability by altering sensorimotor inputs via mechanoreceptors on the plantar surface of the feet. Compared to insoles with indentions in the entire surface, we innovatively developed a textured insole with site-specific nodulous protrudous. This study thus aimed to investigate the immediate effect of the nodulous insole and supporting surface condition on static postural stability and lower limb muscle activation for healthy older women. Methods: This is a single-session study with repeated measurements. Twenty-three healthy older women stood on the firm (i.e., concrete floor) and foam surfaces with their eyes open in the three footwear conditions, namely barefoot, plain shoes and shoes with an innovative textured insole, for 30 seconds. Static postural sway and muscle activation of biceps femoris (BF), vastus lateralis (VL), tibialis anterior (TA), and lateral gastrocnemius (LG) of the dominant leg were measured during each testing condition. Results: Compared to a firm surface, standing on the foam could significantly increase the body sway and lower limb muscle activation (p<0.05). When standing on the foam, compared to barefoot, wearing footwear significantly decreased the VL and TA muscle activation and minimize the postural sway in medial-lateral and anterior-posterior direction, while the influence is larger for the shoes with nodulous insloe compared to the plain shoes. No significant differences between the footwear conditions for static stability and muscle activation were observed on firm surface condition. Conclusions:For older women, footwear could improve the postural stability in the unstable surface, particularly the footwear with nodulous insole, with the underlying mechanism as enhancing the mechanoreceptors on the plantar surface of the feet

OR-039 Normal-weight obesity and physical fitness in Chinese university students: an overlooked association

Objective The primary aim of this study was to examine the associations of normal weight obesity with physical fitness in Chinese university students. As a secondary aim, we assessed whether possible differences in physical fitness between students classified as NWO and normal weight non-obese (NWNO) were mediated by skeletal muscles mass. Methods A total of 383 students (205 males and 178 females, aged 18–24 years) from two universities volunteered to participate in this study. Body height and weight were measured by standard procedures and body composition was assessed by a bio-impedance device (InBody 720). NWO was defined by a BMI of 18.5 - 23.9 kg/m2 and a body fat percentage of &gt; 20% and &gt; 30% in male and female students, respectively. Physical fitness was measured using a 10-min intermittent endurance running test (Andersen test), counter movement jumps (CMJ) and a 5 × 5-m shuttle run test (5mSR). The level of leisure time physical activity (PA) was assessed by a questionnaire. Results &nbsp;13.7% of male and 27.5% of female students were classified as NWO. Compared to NWNO, students classified as NWO showed a significantly poorer performance on the Andersen test (males: 1146 ± 70 m vs. 1046 ± 95 m, females: 968 ± 61 m vs. 907 ± 67m, p &lt; 0.001), CMJ (males: 55.0 ± 7.6 cm vs. 44.9 ± 7.5 cm, females: 39.8 ± 8.0 cm vs. 33.7 ± 5.9 cm, p &lt; 0.001), 5mSR (males: 18.7 ± 1.0 s vs. 20.0 ± 0.9 s, females: 21.1 ± 1.1 s vs. 22.4 ± 1.3 s, p &lt; 0.001), respectively. The lower levels of physical fitness in NWO were partially explained by lower skeletal muscle mass (p &lt; 0.001) both in male and female students Conclusions NWO was associated with poorer physical fitness and the relationship was partially mediated by lower skeletal muscle mass. The study indicated that attention should be paid for the potential hidden health risk in university students with normal body mass index but excessive fat mas

Intrinsic nonlinear Hall effect and gate-switchable Berry curvature sliding in twisted bilayer graphene

Though the observation of quantum anomalous Hall effect and nonlocal transport response reveals nontrivial band topology governed by the Berry curvature in twisted bilayer graphene, some recent works reported nonlinear Hall signals in graphene superlattices which are caused by the extrinsic disorder scattering rather than the intrinsic Berry curvature dipole moment. In this work, we report a Berry curvature dipole induced intrinsic nonlinear Hall effect in high-quality twisted bilayer graphene devices. We also find that the application of the displacement field substantially changes the direction and amplitude of the nonlinear Hall voltages, as a result of a field-induced sliding of the Berry curvature hotspots. Our work not only proves that the Berry curvature dipole could play a dominant role in generating the intrinsic nonlinear Hall signal in graphene superlattices with low disorder densities, but also demonstrates twisted bilayer graphene to be a sensitive and fine-tunable platform for second harmonic generation and rectification

Preparation Process Optimization and Stability Study of Loquat Flower Flavonoid Nanoparticles

In order to improve the stability of loquat flower flavonoids, loquat flower flavonoids/zein/pectin nanoparticles (LF/Z/P Nps) were prepared by anti-solvent precipitation method. Taking the embedding rate, particle size and Zeta potential as indicators, the effects of polysaccharide species, flavonoids concentration, zein concentration, alcohol-to-water ratio and pectin concentration on the preparation of nanoparticles were explored. The preparation process of nanoparticles was optimized by response surface experiment, and the characteristics of nanoparticles were studied. The results showed that the optimal preparation conditions were determined as follows: Loquat flower flavonoids concentration of 0.135 mg/mL, zein concentration of 2.2 mg/mL, alcohol-to-water ratio of 1:4, and pectin concentration of 0.78 mg/mL. Under these conditions, the embedding rate of nanoparticles was 86.20%±0.91%, the average particle size was 132.13±1.31 nm, the PDI was 0.16±0.01, and the Zeta potential was −33.97±1.46 mV. The nanoparticles were sensitive to pH and Na+, but could effectively maintain the antioxidant and stability of loquat flower flavonoids. In this study, LF/Z/P Nps with good stability were prepared by reverse-solvent precipitation method, which laid a certain theoretical basis for improving the processing adaptability of loquat flower flavonoids

Association of lipoprotein lipase (LPL) gene variants with hyperlipidemic acute pancreatitis in southeastern Chinese population

ABSTRACT Objective: The study aims to explore the relationship between lipoprotein lipase (LPL) variants and hyperlipidemic acute pancreatitis (HLAP) in the southeastern Chinese population. Subjects and methods: In total, 80 participants were involved in this study (54 patients with HLAP and 26 controls). All coding regions and intron-exon boundaries of the LPL gene were sequenced. The correlations between variants and phenotypes were also analysed. Results: The rate of rare LPL variants in the HLAP group is 14.81% (8 of 54), higher than in controls. Among the detected four variants (rs3735959, rs371282890, rs761886494 and rs761265900), the most common variant was rs371282890. Further analysis demonstrated that subjects with rs371282890 "GC" genotype had a 2.843-fold higher risk for HLAP (odds ratio [OR]: 2.843, 95% confidence interval [CI]: 1.119-7.225, p = 0.028) than subjects with the "CC" genotype. After adjusting for sex, the association remained significant (adjusted OR: 3.083, 95% CI: 1.208-7.869, p = 0.018). Subjects with rs371282890 "GC" genotype also exhibited significantly elevated total cholesterol, triglyceride and non-high-density lipoprotein cholesterol levels in all the participants and the HLAP group (p < 0.05). Conclusion: Detecting rare variants in LPL might be valuable for identifying higher-risk patients with HLAP and guiding future individualised therapeutic strategies

Pressured HIV testing "in the name of love": a mixed methods analysis of pressured HIV testing among men who have sex with men in China.

INTRODUCTION: HIV testing has rapidly expanded into diverse, decentralized settings. While increasing accessibility to HIV testing is beneficial, it may lead to unintended consequences such as being pressured to test. We examined the frequency, correlates and contexts of pressured HIV testing among Chinese men who have sex with men (MSM) using mixed methods. METHODS: We conducted an online survey of MSM (N = 1044) in May 2017. Pressured HIV testing was defined as being forced to test for HIV. We conducted logistic regression analysis to determine the associations between pressured HIV testing and socio-demographic and sexual behavioural factors. Follow-up interviews (n = 17) were conducted with men who reported pressured testing and we analysed qualitative data using a thematic analysis approach. RESULTS: Ninety-six men (9.2%) reported experiencing pressure to test for HIV. Regular male sex partners were the most common source of pressure (61%, 59/96), and the most common form of pressure was a threat to end a relationship with the one who was being pressured (39%, 37/96). We found a higher risk of pressured testing in men who had only used HIV self-testing compared to men who had never self-tested (AOR 2.39 (95%CI: 1.38 to 4.14)). However, this relationship was only significant among men with low education (AOR 5.88 (95% CI: 1.92 to 17.99)) and not among men with high education (AOR 1.62 (95% CI: 0.85 to 3.10)). After pressured testing, about half of men subsequently tested for HIV (55%, 53/96) without pressure - none reported being diagnosed with HIV. Consistent with this finding, qualitative data suggest that perceptions of pressure existed on a continuum and depended on the relationship status of the one who pressured them. Although being pressured to test was accompanied by negative feelings, men who were pressured into testing often changed their attitude towards HIV testing, testing behaviours, sexual behaviours and relationship with the one who pressured them to test. CONCLUSION: Pressured HIV testing was reported among Chinese MSM, especially from men with low education levels and men who received HIV self-testing. However, in some circumstances, pressure to test helped MSM in several ways, challenging our understanding of the role of agency in the setting of HIV testing

Comparing the effectiveness of a crowdsourced video and a social marketing video in promoting condom use among Chinese men who have sex with men: a study protocol

Crowdsourcing has been used to spur innovation and increase community engagement in public health programmes. Crowdsourcing is the process of giving individual tasks to a large group, often involving open contests and enabled through multisectoral partnerships. Here we describe one crowdsourced video intervention in which a video promoting condom use is produced through an open contest. The aim of this study is to determine whether a crowdsourced intervention is as effective as a social marketing intervention in promoting condom use among high-risk men who have sex with men (MSM) and transgender male-to-female (TG) in China