21 research outputs found
Association of Visceral Fat Area and Hyperuricemia in Non-Obese US Adults: A Cross-Sectional Study
This study aimed to investigate the relationship between visceral fat area (VFA) and hyperuricemia (HUA) among non-obese adults. We extracted data from 6224 US adults aged 20–59 years from the National Health and Nutrition Examination Survey (NHANES) from 2011–2018. The VFA was divided into four quartiles (Q1–Q4). We used multivariable logistic regression models to control for known confounders. A generalized additive model (GAM) and restricted cubic spines were used to examine the association between VFA and HUA stratified by sex, and a two-piecewise linear regression model was used to calculate the threshold effect among males. The results revealed that the prevalence of HUA was 11.8% (men 15.8%, women 7.2%). In the fully adjusted model, there was a positive association between VFA and HUA [as a quartile variable, Q4 vs. Q1, odds ratio (OR): 3.77 and 95% confidence interval (CI): (2.47~5.75), p < 0.001, p for trend < 0.001; as a continuous variable, per 10 cm2 increment, OR (95%CI):1.10(1.07,1.14), p < 0.001]. Besides, this positive association remained significantly stratified by sex. Interestingly, we observed a nonlinear dose-response relationship between VFA and HUA in males (inflection point: 107.46 cm2). In conclusion, our study confirmed a significant positive relationship between VFA and HUA among non-obese adults and remained statistically significant when stratified by sex
Characterization and strengthening mechanism of high-strength medium carbon spring steels
To develop higher strength spring steels with better performance for advanced automotive and transportation industries in line with the trend of lightweight, the strengthening mechanism of two practical 55SiCr and 55SiCrNbV spring steels, which represents plain and micro alloyed spring steels, has been investigated based on the systematic characterization of microstructures, hardness, and tensile test. The tensile strength and hardness were found to be correlated well in a linear relationship. Then the strengthening coefficients of C, Si, Cr and Mn were determined to quantify the solid solution strengthening. The strengthening mechanism of spring steels was found to be the summation of solid solution strengthening, grain refinement, dislocation, and precipitation strengthening, which agree well with the tensile test results. The strengthening mechanism could be used as guidance to develop next generation spring steels, which well explained the ultra-high strength spring steels over 2200Â MPa class in the literature
Hot carrier relaxation in three dimensional gapped Dirac semi-metals
We calculate the relaxation rate of hot carriers in a Cd3As2 semi-metal with a finite gap. The quantization of the transverse momentum gives rise to a minimum gap at the Dirac point. Additional chemical doping further increases the gap. A finite gap relaxes the selection rule and gives rise to a nonvanishing internode coupling via phonon scattering. The gap also enhances the intra-node scattering. It is shown that the relaxation rate is proportional to the square of the gap. By considering the decay of the electron distribution function, we find that the relaxation rate increases with the square of the gap and the electron temperature
Histone Acetylation Induced Transformation of BâDNA to ZâDNA in Cells Probed through FT-IR Spectroscopy
A nucleosome
is made up of DNA and histones, and acetylation of
histones perturbs the interaction of DNA and histones and thus affects
the chromatin conformation and function. However, whether or how acetylation
induces DNA conformation changes is still elusive. In this work, we
applied FT-IR spectroscopy to monitor the DNA signals in cells as
the histone acetylation was regulated by trichostatin A (TSA), a reversible
inhibitor to histone deacetylases (HDACs). Our results unambiguously
demonstrate the significant transformation of B-DNA to Z-DNA upon
histone acetylation in the TSA treated HeLa cells. This is the first
report providing the explicit experimental evidence for such a B-Z
transformation of DNA in the epigenetic states of cells
A Density Functional Theory Study on Pyrolysis Mechanism of Lignin in Hydrogen Plasma
The
reaction mechanism of lignin pyrolysis in hydrogen plasma has been
studied by using phenethyl phenyl ether as the model compound. Density
functional theory was employed here. Many possible reactions were
proposed. All calculations were performed in the Gaussian 09 program,
and the reaction enthalpies and activation energies of these reactions
were determined at the B3LYP/6-31G (d,p) level. Calculation results
indicate that syngas and acetylene are the main products of lignin
pyrolysis in hydrogen plasma. The aldehyde group is the main source
of CO. The dehydrogenation process is responsible for the production
of hydrogen, and active hydrogen atoms in plasma can make it more
favorable. Acetylene mainly comes from the benzene ring and its branch.
A subsequent discussion on biomass pyrolysis in plasma found that
biomass composition has important effects on product distribution.
Syngas can come from both cellulose and lignin, while only lignin
is the main source of acetylene formation
Integration of morphology and electronic structure modulation on cobalt phosphide nanosheets to boost photocatalytic hydrogen evolution from ammonia borane hydrolysis
The controllable and safe hydrogen storage technologies are widely recognized as the main bottleneck for the accomplishment of sustainable hydrogen energy. Ammonia borane (AB) has regarded as a competitive candidate for chemical hydrogen storage. However, developing efficient yet high-performance catalysts towards hydrogen evolution from AB hydrolysis remains an enormous challenge. Herein, cobalt phosphide nanosheets are synthesized by a facile salt-assisted along with low-temperature phosphidation strategy for simultaneously modulating its morphology and electronic structure, and function as hydrogen evolution photocatalysts. Impressively, the Co2P nanosheets display extraordinary performance with a record high turnover frequency of 44.9 minâ1, outperforming most of the noble-metal-free catalysts reported to date. This remarkable performance is attributed to its desired nanosheets structure, featuring with high specific surface area, abundant exposed active sites, and short charge diffusion paths. Our findings provide a novel strategy for regulating metal phosphides with desired phase structure and morphology for energy-related applications and beyond
Discovery of novel 2-aminopyridine derivatives as ROS1 and ALK dual inhibitors to combat drug-resistant mutants including ROS1G2032R and ALKG1202R
AbstractClinical treatment by FDA-approved ROS1/ALK inhibitor Crizotinib significantly improved the therapeutic outcomes. However, the emergence of drug resistance, especially driven by acquired mutations, have become an inevitable problem and worsened the clinical effects of Crizotinib. To combat drug resistance, some novel 2-aminopyridine derivatives were designed rationally based on molecular simulation, then synthesised and subjected to biological test. The preferred spiro derivative C01 exhibited remarkable activity against CD74-ROS1G2032R cell with an IC50 value of 42.3ânM, which was about 30-fold more potent than Crizotinib. Moreover, C01 also potently inhibited enzymatic activity against clinically Crizotinib-resistant ALKG1202R, harbouring a 10-fold potency superior to Crizotinib. Furthermore, molecular dynamic disclosed that introducing the spiro group could reduce the steric hindrance with bulky side chain (Arginine) in solvent region of ROS1G2032R, which explained the sensitivity of C01 to drug-resistant mutant. These results indicated a path forward for the generation of anti Crizotinib-resistant ROS1/ALK dual inhibitors
Broadband photocarrier dynamics and nonlinear absorption of PLD-grown WTe2semimetal films
WTe 2 is a unique material in the family of transition metal dichalcogenides and it has been proposed as a candidate for type-II Weyl semimetals. However, thus far, studies on the optical properties of this emerging material have been significantly hindered by the lack of large-area, high-quality WTe 2 materials. Here, we grow a centimeter-scale, highly crystalline WTe 2 ultrathin film (âŒ35 nm) by a pulsed laser deposition technique. Broadband pump-probe spectroscopy (1.2-2.5 ÎŒm) reveals a peculiar ultrafast optical response where an initial photo-bleaching signal (lasting âŒ3 ps) is followed by a long-lived photoinduced absorption signature. Nonlinear absorption characterization using femtosecond pulses confirms the saturable absorption response of the WTe 2 ultrathin films, and we further demonstrated a mode-locked Thulium fiber laser using a WTe 2 absorber. Our work provides important insights into linear and nonlinear optical responses of WTe 2 thin films
Patientsâ preferences for artificial intelligence applications versus clinicians in disease diagnosis during the SARS-CoV-2 pandemic in China: Discrete choice experiment
Background: Misdiagnosis, arbitrary charges, annoying queues, and clinic waiting times among others are long-standing phenomena in the medical industry across the world. These factors can contribute to patient anxiety about misdiagnosis by clinicians. However, with the increasing growth in use of big data in biomedical and health care communities, the performance of artificial intelligence (Al) techniques of diagnosis is improving and can help avoid medical practice errors, including under the current circumstance of COVID-19. Objective: This study aims to visualize and measure patientsâ heterogeneous preferences from various angles of AI diagnosis versus clinicians in the context of the COVID-19 epidemic in China. We also aim to illustrate the different decision-making factors of the latent class of a discrete choice experiment (DCE) and prospects for the application of AI techniques in judgment and management during the pandemic of SARS-CoV-2 and in the future. Methods: A DCE approach was the main analysis method applied in this paper. Attributes from different dimensions were hypothesized: diagnostic method, outpatient waiting time, diagnosis time, accuracy, follow-up after diagnosis, and diagnostic expense. After that, a questionnaire is formed. With collected data from the DCE questionnaire, we apply Sawtooth software to construct a generalized multinomial logit (GMNL) model, mixed logit model, and latent class model with the data sets. Moreover, we calculate the variablesâ coefficients, standard error, P value, and odds ratio (OR) and form a utility report to present the importance and weighted percentage of attributes. Results: A total of 55.8% of the respondents (428 out of 767) opted for AI diagnosis regardless of the description of the clinicians. In the GMNL model, we found that people prefer the 100% accuracy level the most (OR 4.548, 95% CI 4.048-5.110, P<.001). For the latent class model, the most acceptable model consists of 3 latent classes of respondents. The attributes with the most substantial effects and highest percentage weights are the accuracy (39.29% in general) and expense of diagnosis (21.69% in general), especially the preferences for the diagnosis âaccuracyâ attribute, which is constant across classes. For class 1 and class 3, people prefer the AI + clinicians method (class 1: OR 1.247, 95% CI 1.036-1.463, P<.001; class 3: OR 1.958, 95% CI 1.769-2.167, P<.001). For class 2, people prefer the AI method (OR 1.546, 95% CI 0.883-2.707, P=.37). The OR of levels of attributes increases with the increase of accuracy across all classes. Conclusions: Latent class analysis was prominent and useful in quantifying preferences for attributes of diagnosis choice. Peopleâs preferences for the âaccuracyâ and âdiagnostic expensesâ attributes are palpable. AI will have a potential market. However, accuracy and diagnosis expenses need to be taken into consideration