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Styrene polymerization is a strong exothermic reaction, where the reactants, initiators and diluents are flammable and explosive substances. Once the reaction is out of control, it is extremely easy to cause fire and explosion accidents. In order to analyze the thermal hazards of styrene polymerization reactions, the thermal behaviors of reactions at different reaction conditions are investigated in this paper. Differential scanning calorimeter (DSC) and adiabatic rate calorimeter (ARC) were used to study thermal behavior of styrene polymerization reactions initiated by dual initiators (azodiisobutyronitrile/tert-butyl peroxybenzoate) with different ratios. Reaction calorimetric experiments were performed via reaction calorimeter (RC1e) to analyze the process hazard and calculate thermal hazard parameters. Subsequently, the thermal decomposition properties of the polymerization products were studied by simultaneous thermal analyzer (TGA–DSC). Moreover, the apparent activation energy (Ea) during product decomposition was calculated by Starink and Friedman methods. The results show that the presence of initiators increases the risk of thermal runaway of the reaction. The thermal hazard of styrene polymerization can be reduced due to the addition of ethylbenzene. The most serious consequences of thermal runaway were caused at an early stage. It can be concluded that the reaction of the system containing AIBN initiator reacts at a lower temperature, while the reaction of the system with TBPB is relatively lagged. This study is valuable for the selection of initiator in the polymerization reaction process. [ABSTRACT FROM AUTHOR]

Based on the ERA5 reanalysis dataset, we analyzed the changes in extreme climate indices on the MP from 1981 to 2020, and the relationship between the extreme climate indices and atmospheric circulation indices. The results showed that (1) for temperature, (a) in terms of hot events, the inter-annual variation trends of summer days, warm days, and warm nights have significantly increased across the entire MP, with the central region experiencing a higher probability of extreme hot events. The inter-decadal variation of extreme hot indices showed a considerable increase from the period of 1991 to 2000 to the period of 2001 to 2010. (b) In terms of cold events, a substantial decrease in extreme cold events was revealed, with a great decrease from the period of 1981 to 1990 to the period of 1991 to 2000. (2) For precipitation, there was a decrease in extreme wet indices from 1981 to 2020. The simple precipitation intensity index (SDII) and total precipitation in wet days (PRCPTOT) exhibited a significant descending trend in the northern and northeastern MP. Decadal variations showed a decrease in extreme precipitation events, with a significant decline observed between the period of 1991 to 2000 and the period of 2001 to 2010. (3) For the relationship between the extreme climate indices and atmospheric circulation indices, extreme temperature indices are likely influenced by polar vortices, with the Asian polar vortex area index (APVAI) negatively correlated with extreme hot indices and the Asian polar vortex intensity index (APVII) positively/negatively correlated with most extreme hot and cold indices. Asian zonal circulation index (AZCI) showed significant correlations with most extreme hot and cold indices. Extreme precipitation indices only showed significant negative correlations with the Atlantic Meridional mode (AMM). [ABSTRACT FROM AUTHOR]

In recent years, the prevalence of allergic diseases has increased significantly, causing great concern, and wheat, as one of the top 8 food allergens, is a common allergy trigger. Nevertheless, reliable estimates of the positivity rate of wheat allergens in the allergic population in China are still lacking. The systematic review and meta-analysis aims to evaluate the positive detection rate of wheat allergens in the Chinese allergic population and further provide a reference for the prevention of allergy. CNKI, CQVIP, WAN-FANG DATA, Sino Med, PubMed, Web of Science, Cochrane Library, and Embase databases were retrieved. Related research and case reports about the positive rate of wheat allergen in the Chinese allergic population published from inception to June 30, 2022, were searched, and meta-analysis was performed using Stata software. The pooled positive rate of wheat allergens and 95% confidence interval were calculated by random effect models, and the publication bias was evaluated using Egger's test. A total of 13 articles were included for the final meta-analysis, in which wheat allergen detection methods involved only serum sIgE testing and SPT assessment. The results showed that the wheat allergen positivity detection rate in Chinese allergic patients was 7.30% (95% CI 5.68–8.92%). Subgroup analysis showed that the positivity rate of wheat allergens was influenced by region, but hardly by age and assessment method. The positive rates of wheat allergy in the population with allergic diseases were 2.74% (95% CI 0.90–4.58%) and 11.47% (95% CI 7.08–15.87%) in southern and northern China, respectively. In particular, the positive rates of wheat allergens were greater than 10% in Shaanxi, Henan and Nei Mongol, all of which belong to the northern region. These results suggest that wheat allergens are an important cause of sensitization in allergic populations from northern China, and therefore attention should be paid to early prevention in high-risk populations. [ABSTRACT FROM AUTHOR]

Mitochondrial genome (mitogenome) sequencing is one of the most effective methods for studying spider phylogeny. In this study, the mitogenomes of wolf spiders (Lycosa grahami and Lycosa sp.) were sequenced and compared with those of other spiders to study their evolutionary trends. The mitogenomes of L. grahami and Lycosa sp. were 14,240 and 14,589 bp in length, respectively, and their adenine and thymine contents were 73.74% and 76.23%, respectively. The mitogenomes contained 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs), and a control region. We found that trnS1 and trnS2 of four Lycosa species lacked a dihydrouracil arm, most tRNAs lacked a TΨC arm, and there was a guanine-uracil wobble in the acceptor stem. Comparison of selective pressures on the 13 PCGs in the mitogenomes of Lycosidae showed the fastest evolution for ATP8 and the slowest for COI. Concatenated nucleotide sequences of the 13 PCGs and two rRNA genes were obtained from the mitogenomes of 63 spiders for phylogenetic analysis based on maximum likelihood and Bayesian inference methods. Phylogenetic relationships supported the monophyletic Mesothelae and Mygalomorphae. Lycosa clustered under a monophyletic group in Lycosidae. In addition, L. grahami and L. shansia were found to be more closely related to Lycosa sp. and L. singoriensis, respectively. This study provides crucial molecular information for further studies on the evolution and genetic diversity of the spider mitogenome. [ABSTRACT FROM AUTHOR]

The Roll-to-Roll processing is used in the large-scale industrial production of organic optoelectronic materials, and one common raw material in it is aggregated conjugated polymer. This paper studies the aggregation processes of conjugated polymer (poly(3-hexylselenophene) (P3HS) and poly(3-hexylselenophene) (P3HT)) solutions. The obtained results can be used to guide the production. During the aggregation process of poly(3-hexylselenophene) (P3HS) solutions, maximum soluble absorbance (ABSmsol), concentration of soluble conjugated polymer (Csol) continually decreases. Maximum aggregated absorbance (ABSmagg), concentration of aggregated conjugated polymer (Cagg) continually increases during the aggregation. These parameters can be fitted by an exponential model with different coefficients, and the relationship between ABSmagg and Cagg is a Gaussian model. The relationship of concentration of aggregated conjugated polymer with Hansen Solubility Parameter (HSP) and the changing rate of Cagg ('Cagg) all follow the exponential model well. Poly(3-hexylthiophene) (P3HT) solutions have the same rules as P3HS solutions. In this paper, the phenomena of the aggregation process are explained by Hansen solubility parameter (HSP) and average photon energy (Eave). All conjugated polymer solutions in this paper form J-aggregates with decreasing Eave. This may be a feature for all conjugated polymer solutions with J-aggregates and reflects the decreasing of Gibbs free energy in these aggregation processes. This work provides a simple way for scholars to get more information from already widely used UV–Vis absorption spectra. Researchers can get the relationship between the concentration of conjugated polymer of an aggregation status and the absorbance of UV–Vis absorption spectra of conjugated polymer solutions. [ABSTRACT FROM AUTHOR]

Based on the precipitation records of 2474 meteorological stations, this study investigated precipitation characteristics and trends in China from 1961 to 2010, including spatiotemporal distribution and changes in average annual precipitation amount, number of days when daily precipitation > = 1, 5, 10, 25, 50 mm, and extreme precipitation indices. The results showed that: (1) in terms of annual average precipitation amount, both dry to wet, wet to wetter, and shifting between wet and dry showed decadal and climatical fluctuations in annual precipitation totals in space and time, with a clear shift in space from the 0 to 200 mm and above 400 mm precipitation levels to the 200 to 400 mm precipitation level. (2) In terms of graded precipitation days, three kinds of trend changes were observed: (a) enhancement, manifested as an increase in precipitation events, mainly in the northwest and northeast of China; (b) reduction, manifested as a decrease in precipitation events, mainly in the central parts of China; and (c) polarization, which is manifested as a decrease in gentle and light precipitation events but an increase in dry days, heavy, and rainstorm precipitation events, primarily along coastal area in southeast China. (3) In terms of extreme precipitation events, precipitation persistence showed a decreasing trend, but an increasing trend in precipitation intensity and magnitude in most regions of China. This paper also presents the relationship between certain atmospheric circulation indices and the seasonal precipitation of summer and winter. The distribution characteristics and changes in minor precipitation events were highlighted, including gentle and light rain events. Relevant findings can provide scientific guidance for water resource management and conservation. [ABSTRACT FROM AUTHOR]

The oxidation behaviors of molten WE43 (Mg-4.32Y-2.83Nd-0.41Zr, wt%) in resin-sand mold atmosphere were systematically investigated. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy analyses were employed to identify the phase compositions and microstructures of surface oxide scale. The initial oxide scale characterized by a three-layer structure mainly consisted of MgO, Y2O3, and ZrO2 and then transformed to Y2O3 layers covered by porous MgO after holding at high temperatures. CALPHAD method was used to analyze the oxidation process, and the calculated phase diagrams agreed well with the experimental results. A selective oxidation model was established based on thermodynamic and kinetic analysis to describe the structure transformation of oxide scale in detail. The initial oxidation was controlled by inward diffusion of oxygen due to the protection of surface Y2O3. However, the oxide scale was not protective after long-term oxidation or at temperatures higher than 1073 K due to the oxide fracture, which can be attributed to the increase in stress caused by inner Y2O3 layer growth. Based on experimental results, the oxide growth stress parameter C was estimated to be 0.0013 and 0.0026 for 1023 and 973 K, respectively. This work reveals the underlying oxide growth and fracture mechanisms of molten Mg-Y alloy in mold, and provides guidance for preventing the ignition of magnesium alloys during casting processes. [ABSTRACT FROM AUTHOR]

Ceramic capacitors are receiving increasing interest because of their applications in pulsed-power devices. The perovskite oxide Bi0.5Na0.5TiO3 (BNT)-based ferroelectric ceramics are regarded as prospective lead-free candidate for dielectric capacitors because of the high polarization and outstanding relaxor behaviour. Herein, the relaxor ferroelectric (0.7−x)Bi0.5Na0.5TiO3–0.3SrTiO3–xCa0.7Sm0.2TiO3 ceramics synthesized through solid-state route and exhibited pseudocubic perovskite structure and strong relaxor behaviour. With increasing Ca0.7Sm0.2TiO3 content, the moderate permittivity and reduced grain size contributed to the monotonically increased electric breakdown strength. Among prepared samples, the x = 0.2 ceramic displayed slimmer polarization-electric field curves with a remarkable recoverable energy density (~6.8 J/cm3) and a satisfied efficiency (~82.2%) under external electric field of 450 kV/cm. Moreover, the x = 0.2 ceramic also exhibited a superb thermal reliability of energy storage properties (3.9–4.5 J/cm3 with variation of 13.3% in 25–160 °C) resulting from the diffuse phase transition. The above results make the x = 0.2 ceramics becoming promising candidates for pulsed-power devices. [ABSTRACT FROM AUTHOR]

Photochemical vapor generation (PVG) of germanium (Ge) was first reported in this work. The synergistic effect from cobalt/chloride ions and air-liquid interfaces was found for the PVG of Ge. No obvious signal response was observed from the standard solution of Ge in 10% (v/v) formic acids (FAs) under UV irradiation. The addition of 300 mg L−1 of Co2+ and 30 mmol L−1 of Cl− resulted in enhanced photochemical reduction for Ge, and the introduction of air-liquid interfaces proceeding and succeeding the sample solution caused another 4.6 folds of enhancement in signal response of Ge. Under the selected condition, the limit of detection (LOD, 3σ, n = 11) was obtained to be 0.008 ng mL−1 with inductively coupled plasma mass spectrometry (ICP MS) measurement. A good precision, expressed as a relative standard deviation (RSD, n = 7) of 2.0%, was found from replicated measurements of 2 ng mL−1 of Ge. The generation efficiency was found to be no better than 9 ± 2%. The PVG mechanism of Ge was investigated in this work. The new finding is useful for understanding the principle of PVG, and further exploring the analytical and environmental application of PVG. [ABSTRACT FROM AUTHOR]

Long noncoding RNAs (lncRNAs) were reported to play important roles in the pathogenesis of ischemic stroke (IS). Our study aimed to investigate the role of lncRNA SERPINB9P1 expression in ischemic stroke and the association between SERPINB9P1 polymorphisms and IS risk, as well as examine the correlation of SERPINB9P1 expression and variants with clinical parameters of IS. The SERPINB9P1 levels in human participants and oxygen–glucose deprivation (OGD)–treated human A172 cells were measured by qRT-PCR. The SERPINB9P1 polymorphisms (rs375556 and rs318429) were genotyped by the MassARRAY platform. We found that the SERPINB9P1 expression was significantly downregulated in patients with IS compared with that in healthy controls. On the 14th day in the hospital, the SERPINB9P1 level in patients with moderate and severe stroke was significantly downregulated compared with the normal group. After stratification by gender, the rs375556 polymorphism was significantly associated with susceptibility to female IS in the recessive model, and the significant association remained after adjusting for age. After adjusting for gender and age, rs318429 was significantly associated with FPG and D-D levels, and rs375556 was significantly associated with INR and PTA levels in IS cases. Besides, the lncRNA SERPINB9P1 expressed downregulated in OGD/reoxygenation-treated human A172 cells. In conclusion, the lncRNA SERPINB9P1 may protect against cerebral ischemia–reperfusion injury and neurological impairment after IS. The SERPINB9P1 rs375556 polymorphism was associated with susceptibility to female IS, and SERPINB9P1 polymorphisms may influence the metabolism of blood glucose and regulation of coagulation function in patients with IS. [ABSTRACT FROM AUTHOR]

Several approaches have been tried to reduce Al corrosion in primary and secondary alkaline batteries. The most successful to date has been the addition of ZnO to the electrolyte, which results in the spontaneous deposition of a protective metallic Zn film on the Al surface. However, there is a limited understanding in the literature of the structure of this Zn film and how that structure (i) influences the protection of Al, and (ii) is influenced by the electrolyte composition. This work aims to develop a fundamental understanding of the protection mechanism against Al corrosion when zincate is added to KOH electrolytes. This was accomplished through morphological studies of the resulting Zn film using SEM, XRD, N2 adsorption, and measurements of H2 gas evolution as well as electrochemical characterization during discharge. It was found that adding saturated ZnO to KOH electrolytes provides the most protective Zn film with good adherence and high density, which can lower the Al corrosion rate by 2 orders of magnitude. Moreover, configurations with a capacity near the Al theoretical capacity were achieved. [ABSTRACT FROM AUTHOR]

The long-term variability of direct and diffuse solar radiation at the surface remains unknown for many areas of the world due to the lack of measurements. In this study, two methods, an empirical model and a neural network, are used to estimate annual direct and diffuse solar radiation in North China for the 1959–2016 period. Results reveal that the two methods have a good performance in estimating direct solar radiation (R2 = 0.49–0.95), and the estimation accuracy of diffuse solar radiation can be improved by incorporating the influence of aerosols (R2 = 0.29–0.79). Generally, total and direct solar radiations have significantly decreased with the declining trend in sunshine duration since 1959 (p < 0.01). However, diffuse solar radiation shows a significant (p < 0.01) increasing tendency over the period of 1959–2016. The proportions of direct and diffuse solar radiation are almost equal from 1982 onward. Influenced by the atmospheric aerosols, two periods with large diffuse solar radiation values have been observed from 1959 to 1989 and from 2004 to 2016. Over the period of 2000–2016, sunshine duration and aerosols can explain 89 and 85% of direct and diffuse solar radiation variations, where aerosol concentration accounts for about 63% of changes in diffuse solar radiation. This study characterizes the long-term variability of direct and diffuse solar radiation in North China since 1959 and highlights the significance of aerosols to diffuse solar radiation from 2000 to 2016. [ABSTRACT FROM AUTHOR]

Objectives: To identify whether parameters measured from diffusion kurtosis and intravoxel incoherent motion help diagnose placenta percreta. Methods: We retrospectively enrolled 75 patients with PAS disorders including 13 patients with placenta percreta and 40 patients without PAS disorders. Each patients underwent diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI). The apparent diffusion coefficient (ADC), perfusion fraction (f), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), mean diffusion kurtosis (MK) and mean diffusion coefficient (MD) were measured by the volumetric analysis and compared. MRI features were also analyzed and compared. The receiver operating characteristic (ROC) curve and logistic regression analysis were used to evaluate the diagnostic efficiency of different diffusion parameters and MRI features for distinguishing placental percreta. Results: D* was an independent risk factor from DWI for predicting placenta percreta with sensitivity of 73% and specificity of 76%. Focal exophytic mass remained as independent risk factor from MRI features for predicting placenta percreta with sensitivity of 72.7% and specificity of 88.1%. When the two risk factors were combined together, the AUC was the highest, 0.880 (95% CI 0.8–0.96). Conclusion: D* and focal exophytic mass were associated with placenta percreta. A combination of the 2 risk factors can be used to predict placenta percreta. Critical relevance statement: A combination of D* and focal exophytic mass can be used to differentiate placenta percreta. Key points: D* and focal exophytic mass were associated with placenta percreta. DWI parameters help quantify PAS. Placenta percreta can be differentiated with combination of risk factors. [ABSTRACT FROM AUTHOR]

Background: A variety of imaging techniques can be used to evaluate diffusion characteristics to differentiate malignant and benign pancreatic lesions. The diagnostic performance of diffusion parameters has not been systematic assessed. Purpose: We aimed to investigate the diagnostic efficacy of quantitative diffusion-weighted imaging (DWI) for pancreatic lesions. Methods: A literature search was conducted using the PubMed, Embase, and Cochrane Library databases for studies from inception to March 30, 2020, which involves the quantitative diagnostic performance of diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) in the pancreas. Studies were reviewed according to inclusion and exclusion criteria. The quality of articles was evaluated by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUATAS-2). A bivariate random-effects model was used to evaluate pooled sensitivities and specificities. Univariable meta-regression analysis was used to test the effects of factors that contributed to the heterogeneity. Results: A total of 31 studies involving 1558 patients were ultimately eligible for data extraction. The lowest heterogeneity was found in specificity of perfusion fraction (f) with the I2 value was 17.97% and Cochran p value was 0.28. However, high heterogeneities were found for the other parameters (all I2 > 50%). There was no publication bias found in funnel plot (p = 0.30) for the apparent diffusion coefficient (ADC) parameter. The pooled sensitivities for ADC, f, pure diffusion coefficient (D), and pseudo diffusivity coefficient (D*) were 83%, 81%, 76%, and 84%, respectively. The pooled specificities for ADC, f, D, and D* were 87%, 83%, 69%, and 81% respectively. The areas under the curves for ADC, f, D, and D* were 0.92, 0.87, 0.79, and 0.87 respectively. Conclusion: Quantitative DWI and IVIM have a good diagnostic performance for differentiating malignant and benign pancreatic lesions. Key Points: • IVIM has high sensitivity and specificity (84% and 83%, respectively) for differential diagnosis of pancreatic lesions, which is comparable to that of the ADC (83% and 87%, respectively). • The ADC has an excellent diagnostic performance for differentiating malignant from benign IPMNs (sensitivity, 0.83; specificity, 0.92); the f has the best diagnostic performance for differentiating pancreatic carcinoma from PNET (sensitivity, 0.85; specificity, 0.85). • For the ADC, using a maximal b value < 800 s/mm2has a higher diagnostic accuracy than ≥ 800 s/mm2; performing in a high field strength (3.0 T) system has a higher diagnostic accuracy than a low field strength (1.5 T) for pancreatic lesions. [ABSTRACT FROM AUTHOR]

Single nucleotide polymorphisms (SNPs) and genes associated with susceptibility to hepatitis B virus (HBV) infection that have been identified by genome-wide association studies explain only a limited portion of the known heritability, indicating more genetic variants remain to be discovered. In this study, we adopted a new research strategy to identify more susceptibility genes and variants for HBV infection. We first performed genetic association analysis of 300 sib-pairs and 3,087 case-control samples, which revealed that 36 SNPs located in 31 genes showed nominal associations with HBV infection in both samples. Of these genes, we selected SEC24D for further molecular analysis according to the following two main lines of evidence. First, a time course analysis of the expression profiles from HBV-infected primary human hepatocytes (PHH) demonstrated that SEC24D expression increased markedly as time passed after HBV infection (P = 4.0 × 10−4). Second, SNP rs76459466 in SEC24D was adversely associated with HBV risk (ORmeta = 0.82; Pmeta = 0.002), which again indicated that SEC24D represents a novel susceptibility gene for HBV infection. Moreover, SEC24D appeared to be protective against HBV infection in vitro. Consistently, we found that SEC24D expression was significantly enhanced in non-infected liver tissues (P = 0.002). We conclude that SEC24D is a novel candidate gene linked to susceptibility to HBV infection. [ABSTRACT FROM AUTHOR]

S-1 monotherapy is widely used following gemcitabine failure in pancreatic cancer, especially in East Asia. We performed a meta-analysis to determine whether S-1-based combination therapy had better efficacy and safety compared with S-1 monotherapy. We searched Pubmed, Web of Science, ClinicalTrials.gov, and Cochrane CENTRAL and subsequently included five trials with a total of 690 patients. The combined hazard ratio (HR) or risk ratio; the corresponding 95% confidence intervals of progression-free survival, overall survival, and overall response rate; and grade 3-4 adverse events were examined. Five randomized controlled trials were included. Meta-analysis demonstrated S-1-based combination therapy significantly increased progression-free survival (HR = 0.78, 95% confidence interval [CI]: 0.67-0.90, p = 0.0009) and overall response rate (HR = 1.74, 95% CI: 1.20-2.52, p = 0.003). Evidence was insufficient to confirm that S-1-based combined regimens improved overall survival (HR = 0.87, 95% CI: 0.75-1.00, p = 0.05). There was no significant difference in adverse events between the two treatment arms. In conclusion, S-1-based combination therapy improved progression-free survival and overall response rate compared to S-1 monotherapy with acceptable toxicity. [ABSTRACT FROM AUTHOR]