Improving the catalytic activity of Pt-based bimetallic nanoparticles is a key challenge in the application of proton-exchange membrane fuel cells. Electrochemical dealloying represents a powerful ...approach for tuning the surface structure and morphology of these catalyst nanoparticles. We present a comprehensive study of using electrochemical dealloying methods to control the morphology of ordered Cu3Pt/C intermetallic nanoparticles, which could dramatically affect their electrocatalytic activity for the oxygen reduction reaction (ORR). Depending on the electrochemical dealloying conditions, the nanoparticles with Pt-rich core–shell or porous structures were formed. We further demonstrate that the core–shell and porous morphologies can be combined to achieve the highest ORR activity. This strategy provides new guidelines for optimizing nanoparticles synthesis and improving electrocatalytic activity.
Oxygen transport resistance of catalyst layer (CL) has significant impact on the performance for polymer electrolyte fuel cells (PEFCs). Nano-Polytetrafluoroethylene (PTFE) particles are added into ...CL to improve the oxygen transport resistance. The CV curves indicate that PTFE do not reduce the utilization of Pt. The IV polarization curves suggest that the performance incorporated PTFE in CL gradually improve at high current densities and the output is 0.57 V at 1.8 A cm−2, 70 mV higher than that without PTFE. The water contact angle for CL with 20 wt% PTFE shows that continuous hydrophobic network may not be formed at 150 °C heat treatment temperature. The total transport resistance of CL with PTFE decreases about 2.5% at 70 °C and 250 kPa, mainly caused by the reduction of pressure-independent resistance (Rother). In the Rother reduction, the Knudsen diffusion resistance reduction in CL account for 74%. The pore size distributions reveal that the porosity increases 29% and the proportion of pores at around 100 nm increases for primary pores in CL with PTFE. This finding indicates that not the hydrophobicity of PTFE but the porous structure conducive to Knudsen diffusion for CL plays the predominant role in improving the performance.
•Nano-PTFE were added into catalyst layer to improve the oxygen transport.•The oxygen transport mechanism was analyzed by limiting current method.•Pore size distributions were characterized to clarity the structure change.
Background
Endometrioid adenocarcinoma (EAC) is the most common subtype of endometrial cancer (EC) and is an estrogen-related cancer. In this study, we sought to investigate the expressions and ...mechanism of action of 17β-estradiol (E2) and long noncoding RNA (lncRNA) LINC01541 in G1/G2 EAC samples.
Methods
The expressions of estrogen receptor β (ESR2), LINC01541, miR-200s, and VEGFA were evaluated using real-time PCR in human EAC tissues (n = 8) and adjacent normal tissues (n = 8). Two EC cell lines (Ishikawa and RL95-2) were selected for validation
in vitro
. Bioinformatics analyses and luciferase reporter analyses were performed to verify potential binding sites. qRT-PCR, Western blot, and CCK-8 were used to identify the regulatory mechanisms of related genes in cell biological behavior.
Results
Compared with adjacent normal tissues, LINC01541 and miR-200s family (except miR-200c) were highly expressed in EAC tissues (n=8), while ESR2 and VEGFA were lowly expressed in EAC tissues (*
P
< 0.05; **
P
< 0.01).
In vitro
: E2 inhibited the expression of LINC01541 and miR-429 in both cell lines, and estrogen antagonist (PHTPP) could reverse this effect, in addition, PHTPP could promote the proliferation of these two cancer cells, cell transfection LINC01541 also had this effect after overexpression of plasmid and miR-429 mimic. E2 promotes the expression of VEGFA in both cell lines, and PHTPP can also reverse this effect. LINC01541 interacts with miR-429 to promote the expression of each other, and both inhibit the synthesis of VEGFA in EAC cells after overexpression. Through the double validation of bioinformatics analysis and dual fluorescein reporter gene, it was confirmed that miR-429 targets the regulation of VEGFA expression (*
P
< 0.05; **
P
< 0.01).
Conclusion
E2 promotes the synthesis of VEGFA by altering the expression levels of LINC01541 and miR-429 in EAC, thereby affecting the angiogenesis process of EAC. Also, E2-mediated LINC01541/miR-429 expression may affect cell migration in EAC. In addition, we identified a reciprocal promotion between LINC01541 and miR-429.
Replacing platinum by a less precious metal such as palladium, is highly desirable for lowering the cost of fuel-cell electrocatalysts. However, the instability of palladium in the harsh environment ...of fuel-cell cathodes renders its commercial future bleak. Here we show that by incorporating trace amounts of gold in palladium-based ternary (Pd6CoCu) nanocatalysts, the durability of the catalysts improves markedly. Using aberration-corrected analytical transmission electron microscopy in conjunction with synchrotron X-ray absorption spectroscopy, we show that gold not only galvanically replaces cobalt and copper on the surface, but also penetrates through the Pd-Co-Cu lattice and distributes uniformly within the particles. The uniform incorporation of Au provides a stability boost to the entire host particle, from the surface to the interior. The spontaneous replacement method we have developed is scalable and commercially viable. This work may provide new insight for the large-scale production of non-platinum electrocatalysts for fuel-cell applications.
The formation and characteristics of adiabatic shear band during the fracture of gear assembly were studied. It shows that in the fracture process, the strain required by the adiabatic shear band can ...be achieved near the failure position of the gear, and thus the adiabatic shear band is generated. The distribution of the adiabatic shear band is discontinuous, and the angle with the gear is about 20 ° to 45 °. With the appearance of adiabatic shear band, a high strain rate is produced, and a lot of heat is produced in some areas. And because of the extremely fast speed, these heat can not be transferred in time, resulting in deformation, which leads to the fracture of gear assembly. At the same time, the critical strain and critical temperature are calculated.
In order to identify risk factors contributing to foodborne disease outbreaks in Guangdong province, China, the present study evaluated the knowledge, attitude, and practices (KAP) of food safety ...among food handlers in a coastal resort area that has a high incidence of foodborne disease outbreaks from Vibrio parahaemolyticus. The KAP of 171 food handlers from 22 food establishments—including seven food establishments in which outbreaks had occurred and 15 in which outbreaks had not occurred—were evaluated.
A self-administered questionnaire designed to access the KAP of food safety was completed by the food handlers. The majority of respondents didn't know the maximum stored time at room temperature and the most common agent of foodborne disease in seafood. Most of the respondents' attitudes about food safety and training were positive. When asked about the practices undertaken, about one-fifth of the respondents admitted they had mixed food (raw and cooked) containers in varying degrees. There was significant variance among different food establishments, different ages, and different times of training. Training programs may achieve good results, but training should be more selective, educate the trainees to realize food safety is more important than fresh seafood, target how to cook seafood and lower the risk of microbiology in food, and conduct particularly focused training among managers and newcomers.
•Few respondents know the maximum stored time and the most common agent in seafood.•Most of the respondents' attitudes about food safety and training were positive.•20% of the respondents admitted they had usually mixed raw and cooked food containers.•Training programs should be increased among managers and new chefs.•Training programs should target how to lower the risk of microbiology in sea food.
Abstract
This paper studies the corrosion of the base of the 30CrMnSi hydraulic cylinder due to changes in emulsion concentration during maintenance and its effect on alloy performance. The results ...show that the corrosion characteristics of the base of the hydraulic cylinder are comprehensive corrosion and local point corrosion, and that the anti-rust performance of emulsion in contact with the outer surface of the hydraulic cylinder base is insufficient, and the chemical reaction with its surface is the main cause of the corrosion of the components. According to the analysis, the hydraulic cylinder base can not be stored at a reasonable emulsion concentration, resulting in a decrease in its surface pitting potential, so that its ability to cope with environmental corrosion decreased, after a period of time, rust on its surface.
Abstract
In this paper, it’s studied that the characteristics and causes of the adiabatic shear band produced by the expansion and deformation of the barrel muzzle during the firing of shells. The ...results show that the failure property of the barrel during the launching process belongs to plastic distortion failure, and the adiabatic shear band produced in the failure process is caused by the abnormal contact and collision between the barrel and its internal components. It is easy to promote the generation of adiabatic shear band, when the material strength (hardness) is high, but the local strain is large.
Congenital heart defects are the most prevalent type of birth defects. The association of air pollution with congenital heart defects is not well understood. We investigated a cohort of 8969 ...singleton live births in Lanzhou, China during 2010-2012. Using inverse distance weighting, maternal exposures to particulate matter with diameters ≤10 m (PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2) were estimated as a combination of monitoring station levels for time spent at home and in a work location. We used logistic regression to estimate the associations, adjusting for maternal age, education, income, BMI, disease, folic acid intake and therapeutic drug use, and smoking; season of conception, fuel used for cooking and temperature. We found significant positive associations of Patent Ductus Arteriosus (PDA) with PM10 during the 1st trimester, 2nd trimester and the entire pregnancy (OR 1st trimester = 3.96, 95% confidence interval (CI): 1.36, 11.53; OR 2nd trimester = 3.59, 95% CI: 1.57, 8.22; OR entire pregnancy = 2.09, 95% CI: 1.21, 3.62, per interquartile range (IQR) increment for PM10 (IQR = 71.2, 61.6, and 27.4 g m−3, respectively)), and associations with NO2 during 2nd trimester and the entire pregnancy (OR 2nd trimester = 1.92, 95% CI: 1.11, 3.34; OR entire pregnancy = 2.32, 95% Cl: 1.14, 4.71, per IQR increment for NO2 (IQR = 13.4 and 10.9 g m−3, respectively)). The associations for congenital malformations of the great arteries and pooled cases showed consistent patterns. We also found positive associations for congenital malformations of cardiac septa with PM10 exposures in the 2nd trimester and the entire pregnancy, and SO2 exposures in the entire pregnancy. Results indicate a health burden from maternal exposures to air pollution, with increased risk of congenital heart defects.
Background: The relationship between air borne particulate matter ≤10 m (PM10) exposure and pregnancy-induced hypertension (PIH) is inconclusive. Few studies have been conducted, and fewer were ...conducted in areas with high levels of PM10. Methods: To examine the association between PM10 and PIH by different exposure time windows during pregnancy, we analyzed data from a birth cohort study conducted in Lanzhou, China including 8 745 pregnant women with available information on air pollution during pregnancy. A total of 333 PIH cases (127 gestational hypertension (GH) and 206 preeclampsia (PE)) were identified. PM10 daily average concentrations of each subject were calculated according to the distance between home work addresses and monitor stations using an inverse-distance weighting approach. Results: Average PM10 concentration over the duration of entire pregnancy was significantly associated with PIH (OR = 1.12, 95%CI: 1.02, 1.23 per 10 g m−3 increase), PE (OR = 1.16, 95%CI: 1.03, 1.30 per 10 g m−3 increase), late onset PE (OR = 1.17, 95% CI: 1.03, 1.32 per10 g m−3 increase), and severe PE (OR = 1.25, 95% CI: 1.06, 1.48 per 10 g m−3 increase). Average PM10 during the first 12 gestational weeks was associated with the risk of GH (OR = 1.10, 95% CI: 1.00, 1.21 per 10 g m−3 increase), and PM10 exposure before 20 gestational weeks was associated with the risk of severe PE (OR = 1.14, 95% CI: 1.01, 1.30 per 10 g m−3 increase). Conclusions: We found that high level exposure to ambient PM10 during pregnancy was associated with an increased risk of PIH, GH and PE and that the strength of the association varied by timing of exposure during pregnancy.
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