Deeper understanding of cobalt-doped SiC nanowires as excellent electromagnetic wave absorbers

Doping is a facile and effective technique that plays a key role in the function of many semiconductor materials. Unraveling the regulatory mechanism of doping can offer useful guidance for the design of the material structure and fabricating novel functional composites invalid in pure phase structures, which extents their applications in catalysts, light emitting devices, and environmental protection. Especially, transition metal doping related to the spin and charge introduces foreign states to the electronic structures in the host materials and endows the composites with intriguing properties. However, most of the reported papers are limited on the fabrication of the doped composites with enhanced performance. Little progress has been made to clarify the underlying mechanism for those improvements. Herein, Co-doped SiC nanowires with different Co contents were successfully fabricated by a simple carbothermal reduction method. The Co-doped SiC nanowires were characterized in terms of microstructure, electronic structure, and electromagnetic (EM) parameters to study the effects of doping on enhancing the EM wave absorption ability. Both the microstructure analysis and density functional theory calculations indicated that the incorporation of Co into SiC nanowires inhibited the formation of defective structures but increased their conductivity. Thus, the improved electronic transportation ability was dominant in enhancing the dielectric loss. The Co dopants also imparted the Co-doped SiC nanowires with magnetic property, which could generate magnetic resonance to attenuate EM wave and achieve superior impedance matching. The induced synergistic effects between Co dopants and SiC nanowires endowed Co-doped SiC nanowires with excellent EM wave absorption ability. Their minimum reflection loss was -50 dB, and the effective absorption bandwidth was up to 4.0 GHz at 1.5 mm sample thickness. Therefore, the fabricated Co-doped SiC nanowires are potential candidates for high-efficiency EM wave absorption materials. The findings of this research provide a guideline for other doped functional composites. Please click Additional Files below to see the full abstract

The Asian Games, Air Pollution and Birth Outcomes in South China: An Instrumental Variable Approach

We estimate the causal effects of air pollution exposure on low birthweight, birthweight, and prematurity risk in South China, for all expectant mothers and by maternal age group and child sex. We do so by exploiting exogenous improvement in air quality during the 2010 Guangzhou Asian Games, when strict regulations were mandated to assure better air quality. We use daily air pollution levels collected from monitoring stations in Guangzhou, the Asian Games host city, and Shenzhen, a nearby control city, between 2009 and 2011. We first show that air quality during the Asian Games significantly improved in Guangzhou, relative to Shenzhen. Further, using birth-certificate data for both cities for 2009 to 2011 and using expected pregnancy overlap with the Asian Games as an instrumental variable, we study the effects of three pollutants (PM10, SO2, NO2) on birth outcomes. Results show that 1) air pollutants significantly reduced average birthweight and increased preterm risk; 2) for birthweight, late pregnancy is most sensitive to PM10 exposure, but there is not consistent evidence of a sensitive period for other pollutants and outcomes; 3) for birthweight, babies of mothers who are at least 35 years old show more vulnerability to all three air pollutants; and 4) male babies show more vulnerability than female babies to PM10 and SO2, but birthweights of female babies are more sensitive than those of male babies to NO2

Erratum - Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) ameliorates sepsis-associated acute kidney injury by maintaining mitochondrial homeostasis and improving the mitochondrial function

This corrects the article published in European Journal of Histochemistry 2022;66:3412. doi: 10.4081/ejh.2022.3412

TRIGO: Benchmarking Formal Mathematical Proof Reduction for Generative Language Models

Automated theorem proving (ATP) has become an appealing domain for exploring the reasoning ability of the recent successful generative language models. However, current ATP benchmarks mainly focus on symbolic inference, but rarely involve the understanding of complex number combination reasoning. In this work, we propose TRIGO, an ATP benchmark that not only requires a model to reduce a trigonometric expression with step-by-step proofs but also evaluates a generative LM's reasoning ability on formulas and its capability to manipulate, group, and factor number terms. We gather trigonometric expressions and their reduced forms from the web, annotate the simplification process manually, and translate it into the Lean formal language system. We then automatically generate additional examples from the annotated samples to expand the dataset. Furthermore, we develop an automatic generator based on Lean-Gym to create dataset splits of varying difficulties and distributions in order to thoroughly analyze the model's generalization ability. Our extensive experiments show our proposed TRIGO poses a new challenge for advanced generative LM's including GPT-4 which is pre-trained on a considerable amount of open-source formal theorem-proving language data, and provide a new tool to study the generative LM's ability on both formal and mathematical reasoning.Comment: Accepted by EMNLP 2023. Code is available at https://github.com/menik1126/TRIG

Ceramides and metabolic profiles of patients with acute coronary disease: a cross-sectional study

Metabolic Syndrome (MS) is a rapidly growing medical problem worldwide and is characterized by a cluster of age-related metabolic risk factors. The presence of MS increases the likelihood of developing atherosclerosis and significantly raises the morbidity/mortality rate of acute coronary syndrome (ACS) patients. Early detection of MS is crucial, and biomarkers, particularly blood-based, play a vital role in this process. This cross-sectional study focused on the investigation of certain plasma ceramides (Cer14:0, Cer16:0, Cer18:0, Cer20:0, Cer22:0, and Cer24:1) as potential blood biomarkers for MS due to their previously documented dysregulated function in MS patients. A total of 695 ACS patients were enrolled, with 286 diagnosed with MS (ACS-MS) and 409 without MS (ACS-nonMS) serving as the control group. Plasma ceramide concentrations were measured by LC-MS/MS assay and analyzed through various statistical methods. The results revealed that Cer18:0, Cer20:0, Cer22:0, and Cer24:1 were significantly correlated with the presence of MS risk factors. Upon further examination, Cer18:0 emerged as a promising biomarker for early MS detection and risk stratification, as its plasma concentration showed a significant sensitivity to minor changes in MS risk status in participants. This cross-sectional observational study was a secondary analysis of a multicenter prospective observational cohort study (Chinese Clinical Trial Registry, https://www.who.int/clinical-trials-registry-platform/network/primary-registries/chinese-clinical-trial-registry-(chictr), ChiCTR-2200056697), conducted from April 2021 to August 2022

Effects of air pollution on neonatal prematurity in guangzhou of china: a time-series study

<p>Abstract</p> <p>Background</p> <p>Over the last decade, a few studies have investigated the possible adverse effects of ambient air pollution on preterm birth. However, the correlation between them still remains unclear, due to insufficient evidences.</p> <p>Methods</p> <p>The correlation between air pollution and preterm birth in Guangzhou city was examined by using the Generalized Additive Model (GAM) extended Poisson regression model in which we controlled the confounding factors such as meteorological factors, time trends, weather and day of the week (DOW). We also adjusted the co linearity of air pollutants by using Principal Component Analysis. The meteorological data and air pollution data were obtained from the Meteorological Bureau and the Environmental Monitoring Centre, while the medical records of newborns were collected from the perinatal health database of all obstetric institutions in Guangzhou, China in 2007.</p> <p>Results</p> <p>In 2007, the average daily concentrations of NO₂, PM₁₀and SO₂in Guangzhou, were 61.04, 82.51 and 51.67 μg/m³respectively, where each day an average of 21.47 preterm babies were delivered. Pearson correlation analysis suggested a negative correlation between the concentrations of NO₂, PM₁₀, SO_2,and temperature as well as relative humidity. As for the time-series GAM analysis, the results of single air pollutant model suggested that the cumulative effects of NO₂, PM₁₀and SO₂reached its peak on day 3, day 4 and day 3 respectively. An increase of 100 μg/m³of air pollutants corresponded to relative risks (RRs) of 1.0542 (95%CI: 1.0080 ~1.1003), 1.0688 (95%CI: 1.0074 ~1.1301) and 1.1298 (95%CI: 1.0480 ~1.2116) respectively. After adjusting co linearity by using the Principal Component Analysis, the GAM model of the three air pollutants suggested that an increase of 100 μg/m³of air pollutants corresponded to RRs of 1.0185 (95%CI: 1.0056~1.0313), 1.0215 (95%CI: 1.0066 ~1.0365) and 1.0326 (95%CI: 1.0101 ~1.0552) on day 0; and RRs of the three air pollutants, at their strongest cumulative effects, were 1.0219 (95%CI: 1.0053~1.0386), 1.0274 (95%CI: 1.0066~1.0482) and 1.0388 (95%CI: 1.0096 ~1.0681) respectively.</p> <p>Conclusions</p> <p>This study indicates that the daily concentrations of air pollutants such as NO₂, PM₁₀and SO₂have a positive correlation with the preterm births in Guangzhou, China.</p

Research Progress of High Temperature Microwave Absorption Materials

High temperature microwave absorption material is significantly important to improve the viability of advanced weapon and equipment. This paper summarizes the research progress of high temperature microwave absorption materials. The current research status of SiC based oxygen-free ceramic materials, laminated ternary ceramics (MAX phases), carbon materials and metal oxides, including the methods of manipulating the electronic structure, doping, designing multilayer structure and designing porous structure to improve their absorption properties, together with the related mechanism is discussed. Oxidation and unclear mechanisms for microwave absorption performance at high temperature are the main problems in the present research of high temperature microwave absorption materials. Finally, the trend of developing applied research and designing smart high temperature microwave absorption material is also prospected

Early use of polymyxin B reduces the mortality of carbapenem-resistant Klebsiella pneumoniae bloodstream infection

ABSTRACT Polymyxin B is one of the last resort option for carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection in China. Therefore, the timing of administration of polymyxin is frequently delayed. We collected 40 cases of CRKP bloodstream infections (BSIs) treated with combinations based on polymyxin B over 30 months. The primary outcome, 30-day mortality rate, was 52.5% (21/40). Early administration of polymyxin B is meant to administer the drug within 48 h of diagnosing bacteremia. Delayed administration was considered when polymyxin B was administered after 48 h of bacteremia onset. Polymyxin B duration and total dosages were similar in the two groups (11.57 days versus 11.76 days, p = 0.919; 1306.52 mg versus 1247.06 mg, p = 0.711). Compared with delayed administration, early use of polymyxin B-based combination therapy had a significant increase in the rate of bacterial clearance (65.22% versus 29.41%, p = 0.025; OR = 0.533) and decreased 30-day mortality (39.13% versus 70.59%, p = 0.045; OR = 0.461) and overall mortality (43.48% versus 82.35%, p = 0.022; OR = 0.321)

A Novel Position Compensation Scheme for Cable-Pulley Mechanisms Used in Laparoscopic Surgical Robots

The tendon driven mechanism using a cable and pulley to transmit power is adopted by many surgical robots. However, backlash hysteresis objectively exists in cable-pulley mechanisms, and this nonlinear problem is a great challenge in precise position control during the surgical procedure. Previous studies mainly focused on the transmission characteristics of the cable-driven system and constructed transmission models under particular assumptions to solve nonlinear problems. However, these approaches are limited because the modeling process is complex and the transmission models lack general applicability. This paper presents a novel position compensation control scheme to reduce the impact of backlash hysteresis on the positioning accuracy of surgical robots’ end-effectors. In this paper, a position compensation scheme using a support vector machine based on feedforward control is presented to reduce the position tracking error. To validate the proposed approach, experimental validations are conducted on our cable-pulley system and comparative experiments are carried out. The results show remarkable improvements in the performance of reducing the positioning error for the use of the proposed scheme