Divergent changes in aerosol optical hygroscopicity and new particle formation induced by heatwaves

As a crucial climate-forcing driver, the aerosol optical enhancement factor (f(RH)) is significantly modulated by the evolution of particle number size distribution (PNSD), e.g., during new particle formation (NPF). The mechanisms regulating aerosol optical hygroscopicity during different NPF events and non-event days, particularly those influenced by heatwaves due to global warming, remain poorly understood. In the extremely hot summer of 2022 in urban Chongqing of southwest China, simultaneous measurements of aerosol optical and hygroscopic properties, PNSD, and bulk chemical compositions were conducted. Two distinct types of NPF were identified: the ones with relatively polluted period (P1) and clean cases during heatwave-dominated period (P2). Heatwaves triggered NPF earlier and prolonged the subsequent growth, resulting in smaller aerosol effective radius (Reff) and lower growth rate. This agreed with the concurrently increased aerosol hemispheric backscattering fraction and scattering Ångström exponent. f(RH) was generally higher during NPF events in comparison to that for non-event cases in both periods. Heatwave-induced stronger photooxidation may intensify the formation of more hygroscopic secondary components, as well as the subsequent growth of pre-existing particles and newly formed ultrafine ones, thereby enhancing aerosol optical hygroscopicity especially during heatwave-influenced NPF events. The promoted f(RH) and lowered Reff could synergistically elevate the aerosol direct radiative forcing, specifically under persistent heatwave conditions. Further in-depth exploration on molecular-level characterizations and aerosol radiative impacts of both direct and indirect interactions during weather extremes (e.g., heatwaves) with the warming climate are recommended

RESEARCH ON CALCULATION METHOD OF AXIAL COMPRESSION LOAD-CARRYING CAPACITY OF INTEGRALLY STIFFENED PANEL

The accurate calculation of load-carrying capacity of integrally stiffened panels under axial compression is the key factor for designing and analyzing of wing panel,which is essential for the aircraft wing structural efficiency and weight control,it is necessary to study a method that can calculate the load-carrying capacity of integrally stiffened panels under axial compression accurately. This paper proposes the equivalent calculating method based on the bending resistance of stiffened panels,axial compression tests of stiffened panels have verified the accuracy of the calculation method for the three types skin effective width,influences of shot peening on compressive strength of wing stiffened panel are considered by comparison on crippling test results of shot peened and unpeened panel element,afterwards,a more perfect and accurate,practical engineering calculation method is established

Nanocoating cellulose paper based microextraction combined with nanospray mass spectrometry for rapid and facile quantitation of ribonucleosides in human urine

A rapid and facile analytical method for quantification of ribonucleosides in human urine was developed by the combination of nanocoating cellulose paper based microextraction and nanoelectrospray ionization-tandem mass spectrometry (nESI-MS/MS). Cellulose paper used for microextraction was modified by nano-precision deposition of uniform ultrathin zirconia gel film using a sol-gel process. Due to the large surface area of the cellulose paper and the strong affinity between zirconia and the cis-diol compounds, the target analytes were selectively extracted from the complex matrix. Thus, the detection sensitivity was greatly improved. Typically, the nanocoating cellulose paper was immersed into the diluted urine for selective extraction of target analytes, then the extracted analytes were subjected to nESI-MS/MS detection. The whole analytical procedure could be completed within 10 min. The method was evaluated by the determination of ribonucleosides (adenosine, cytidine, uridine, guanosine) in urine sample. The signal intensities of the ribonuclesides extracted by the nanocoating cellulose paper were greatly enhanced by 136-459-folds compared with the one of the unmodified cellulose paper based microextraction. The limits of detection (LODs) and the limits of quantification (LOQs) of the four ribonucleosides were in the range of 0.0136-1.258 mu g L-1 and 0.0454-4.194 mu g L-1, respectively. The recoveries of the target nucleosides from spiked human urine were in the range of 75.64-103.49% with the relative standard deviations (RSDs) less than 9.36%. The results demonstrate the potential of the proposed method for rapid and facile determination of endogenous ribonucleosides in urine sample

CD44V3, an Alternatively Spliced Form of CD44, Promotes Pancreatic Cancer Progression

Pancreatic cancer is one of the most lethal malignant tumors. However, the molecular mechanisms responsible for its progression are little known. This study aimed to understand the regulatory role of CD44V3 in pancreatic cancer. A Kaplan–Meier analysis was performed to reveal the correlation between CD44/CD44V3 expression and the prognosis of pancreatic cancer patients. CD44V3 and U2AF1 were knocked down using shRNAs. The proliferation, migration, invasion, and stemness of two pancreatic cell lines, BxPC-3 and AsPC-1, were examined. The expression of CD44V3, cancer-associated markers, and the activation of AKT signaling were detected by qRT-PCR and Western blot. Both CD44 and CD44V3 expression levels were associated with a poor prognosis in pancreatic cancer patients. Interestingly, the expression of CD44V3, instead of CD44, was greatly increased in tumor tissues. CD44V3 knockdown inhibited the proliferation, migration, invasion, and stemness of cancer cells. CD44V3 splicing was regulated by U2AF1 and downregulation of U2AF1 enhanced CD44V3 expression, which promoted pancreatic cancer progression. CD44V3 is an important cancer-promoting factor, which may serve as a potential candidate for pancreatic cancer intervention

Experimental Investigation on Indoor/Outdoor PM2.5 Concentrations of an Office Building Located in Guangzhou

AbstractThe Pearl River Delta (PRD) is one of the areas that are facing a serious fine particulate matter (PM2.5) pollution in China. In order to grasp the variation law of PM2.5 concentrations in the atmospheric environment and its impact on the indoor environment, this research has taken a certain naturally ventilated office building as the monitoring object to constantly monitor its mass concentration of indoor and outdoor PM2.5 and meteorological parameters from February to July 2014 and from December 2014 to January 2015 in Guangzhou. During the test period, the external windows and mechanical ventilation system stayed closed and there were no other indoor pollution sources. The survey results showed: (1) among all diurnal variations, the diurnal variation in hourly average mass concentrations for outdoor PM2.5 showed that the night experienced greater variation than the day; in terms of seasonal variation, Spring experienced the most severe outdoor PM2.5 mass pollution (115μg/m3), followed by Winter (95μg/m3); (2) the indoor PM2.5 mass concentrations were highly correlated with that outdoor, meanwhile the indoor/outdoor PM2.5 mass concentrations ratios (I/O ratios) were in a broad range; (3) both outdoor PM2.5 mass concentrations and infiltration factors were significantly correlated with meteorological parameters (temperature, wind speed and relative humidity); (4) compared with the related research conducted on Beijing, PM2.5 concentrations and infiltration factors in both the two regions were affected by wind speed and relative humidity, but the impact of temperature on outdoor PM2.5 concentrations was not discernible in Beijing. The research results can serve as a reference for analyzing the influence rule of outdoor PM2.5 situation to the indoor environment in the Pearl River Delta region and its control technology

Impact of the external window crack structure on indoor PM2.5 mass concentration

The fine particulate matter, generally known as PM2.5, has great impact on the air quality and human health. Although closing external windows can help prevent outdoor PM2.5 going into indoors, many studies have shown that a significant number of particles can still pass the building façade through the cracks around the window. In order to quantify the influence of the external window crack structure and some relevant parameters, such as room dimension, on the indoor PM2.5 mass concentration, this paper introduces an updated model from a previously published paper by the authors [18]. The model was developed based on two-month field measured data from five unoccupied offices located in the central area of Beijing (capital city located in northern China), and then was validated against a new dataset measured in Guangzhou (a major city located in southern China). The model can be used to quantify the indoor PM2.5 mass concentration based on the instant outdoor PM2.5 level, considering influences from external window crack structure, room dimension and outdoor meteorological conditions, i.e. outdoor wind speed and relative humidity

Mechanical Analysis of Frictional Continuous Cable Systems Considering the Influence of Load Path

Continuous cables are widespread in various fields, and mechanical analysis is an important issue in their application. The structural responses of frictional continuous cable systems under external loads are related to the load path. The influence of load path has seldom been considered in the existing analysis methods. This paper proposes a novel approach for the mechanical analysis of continuous cable systems considering the influence of load path. The constitutive relation of the frictional continuous cables was derived, in which the sliding amount parameters were eliminated. The computational frameworks for both definite and indefinite load path cases were proposed. For a definite load path, the structural responses can be uniquely determined by successively trials and modifications of the nodal sliding state. For an indefinite load path, a formula of all the possible structural responses was derived, and the ranges of the structural responses can be obtained. All computations in the approach were converted to matrix operations. The effectiveness and practicability of the proposed approach were demonstrated by two typical numerical examples

Downregulation of PRAME Suppresses Proliferation and Promotes Apoptosis in Hepatocellular Carcinoma Through the Activation of P53 Mediated Pathway

Background/Aims: The expression of PRAME and its role in hepatocellular carcinoma (HCC) remain unknown. The aim of this study was to examine the functional role of PRAME in HCC development and exploring the molecular mechanism. Methods: We first detected PRAME expression in 96 human HCC tissue samples and correlated with clinicopathological characteristics and prognosis of the patients. We then established stable HCC cell lines with PRAME overexpression and knockdown followed by functional analysis in vitro. Further, we examined the relationship between PRAME and p53 pathway in vitro by using Western blotting. Finally, PRAME expression was detected to evaluate its correlation with p-p53 and p53 pathway related apoptotic proteins in xenograft tumor mouse model using immunohistochemistry. Results: PRAME expression was significantly higher in HCC tissues than in adjacent non-tumor tissues and their expression was positively correlated with alpha fetoprotein levels and tumor size. In addition, PRAME expression was associated with AJCC stage and is a potential biomarker of poor prognosis regarding 5-year overall survival in HCC. In vitro studies, we found that PRAME expression was higher in HCC cell lines than in normal hepatic cell line. Inhibited cell proliferation and increased cell apoptosis was observed in PRAME knockdown HCC cells. Futher, increased cell apoptosis was correlated with the proportion of cells in G0/G1 stage, activated p53 mediated apoptosis, and increased cyclin p21 expression. Xenograft analysis in nude mice also found that PRAME knockdown inhibited tumorigenesis while PRAME overexpression had opposite effect. Conclusions: In HCC, PRAME serves as a potential biomarker for poor prognosis and novel therapeutic target in treating this cancer. PRAME is a potential biomarker of poor prognosis in HCC. PRAME surpresses HCC cell death in vitro and in vivo by regulating p53 apoptotic signaling and may serve as a potential therapeutic target in HCC