24 research outputs found
Seismic Performance Evaluation of Highway Bridges under Scour and Chloride Ion Corrosion
Cross-river bridges located in seismically active areas are exposed to two major natural hazards, namely earthquakes and flooding. As the scour depth increases, more parts of the bridge substructure will inevitably be exposed to unfavorable conditions such as chloride ion (Cl−) corrosion. To investigate the seismic performance of highway bridges under the action of scour and Cl− corrosion, a spatial finite element dynamic model of a continuous rigid bridge was established and a Cl−-accelerated electrochemical corrosion test and quasi-static test were carried out. The results showed that a reasonable scour depth and the combination sub-factors under the joint probability density of scour action and seismic action can be obtained to establish the combined expression of the action effect. Cl− corrosion can cause a reduction in displacement ductility, load-bearing, and energy dissipation capacity, and increase inequivalent viscous damping coefficient of the columns. Seismic damage of the columns grows linearly to twice the ultimate displacement under Cl− corrosion, which becomes more significant with the increase of the reinforcement ratio
Cryogenian interglacial greenhouse driven by enhanced volcanism: Evidence from mercury records
An ice-free greenhouse interval (ca. 660 similar to 650 Ma) occurred between the global Sturtian (ca. 717Ma similar to 660Ma) and Marinoan glaciation (ca. 650Ma similar to 635Ma) during the Cryogenian. While volcanic CO2 emissions have been suggested as a trigger for this ice-free interval, evidence for volcanism has been lacking. In this study, spikes in both Hg concentration (76 to 366 ppb) and Hg to total organic carbon ratio (Hg/TOC: 114 to 717 ppb/wt.%) were observed in the Wuhe section of South China, suggesting that extensive volcanic emissions of Hg occurred during the Cryogenian interglacial period. Positive Delta Hg-199 (0.02 to 0.18 parts per thousand) values were observed in these Hg-rich shales, indicating that the volcanic Hg was cycling in the atmosphere, deposited in seawater, and sequestered to sediment via organic matter burial. Combined with other geochemical proxies (e.g., organic carbon isotope and chemical index of alteration), our results provide the first direct evidence that volcanism played a key role in forming the brief Cryogenian interglacial period. (C) 2021 Elsevier B.V. All rights reserved.11Nsciescopu
Combination of Astragali Polysaccharide and Curcumin Improves the Morphological Structure of Tumor Vessels and Induces Tumor Vascular Normalization to Inhibit the Growth of Hepatocellular Carcinoma
Interaction between diet- and exercise-lifestyle and phthalates exposure on sex hormone levels
Phthalate can affect sex hormones secretion. Exercise and diet habits affect sex hormones levels. However, interaction of phthalates exposure and diet or exercise habits with sex hormones is unclear. We enrolled 106 residents aged 11-88 years (48 males and 58 females) from two communities, Wuhan city, China during the winter of 2014 and summer of 2015. Data were collected on socio-demographic characteristics and lifestyle by a questionnaire in two seasons. Participants provided the blood and urine samples over 3 consecutive days for measuring sex hormones and urinary phthalate metabolites. We assessed the associations of urinary phthalate metabolites levels, lifestyle with hormones levels, the interaction of phthalate exposure and lifestyle with hormones levels using multivariate binary logistic regression models. High urinary mono-(2-ethyl-5-oxyhexyl) phthalate (MEOHP) levels and no exercise had an additive interaction on abnormal serum progesterone (PROG) levels in winter as well as on abnormal serum follicle-stimulating hormone (FSH) or luteinizing hormone (LH) levels in summer. High urinary MEOHP levels and red meat intake (> 1 time/day) had an additive interaction with abnormal levels of serum FSH only in the winter. Phthalates exposure may confer differential susceptibility to abnormal hormones levels in individuals with no exercise or eating meat > 1 time/day
N-Sulfonyl Dipeptide Nitriles as Inhibitors of Human Cathepsin S: In silico Design, Synthesis and Biochemical Characterization
A library of cathepsin S inhibitors of the dipeptide nitrile chemotype, bearing a bioisosteric sulfonamide moiety, was synthesized. Kinetic investigations were performed at four human cysteine proteases, i.e. cathepsins S, B, K and L. Compound 12 with a terminal 3-biphenyl sulfonamide substituent was the most potent (Ki = 4.02 nM; selectivity ratio cathepsin S/K = 5.8; S/L = 67) and 24 with a 4′-fluoro-4-biphenyl sulfonamide substituent the most selective cathepsin S inhibitor (Ki = 35.5 nM; selectivity ratio cathepsin S/K = 57; S/L = 31). In silico design and biochemical evaluation emphasized the impact of the sulfonamide linkage on selectivity and a possible switch of P2 and P3 substituents with respect to the occupation of the corresponding binding sites of cathepsin S
Seasonal modification of the associations of exposure to polycyclic aromatic hydrocarbons or phthalates of cellular aging
Exposure to polycyclic aromatic hydrocarbons (PAHs) and phthalates link to oxidative stress and inflammatory response, which exert cellular aging. However, modification effect of seasonal factor on the association of PAHs or phthalates exposure with relative telomere length (RTL) or mitochondria] DNA copy number (mtDNA-CN) has remained unclear. In this pilot study, 106 subjects were from an urban population (n = 1240) who lived in the two districts in Wuhan city, China. Participants completed physical examinations and provided 191 blood samples for RTL and mtDNA-CN analysis and 627 urine samples for monohydroxylated-PAHs (OH-PAHs) and phthalate metabolites measurements in the winter and summer seasons. We assessed the associations of urinary OH-PAHs or phthalates metabolites with RTL or mtDNA-CN by linear regression analysis and linear mixed-effect models. We found that urinary OH-PAHs were positively associated with mtDNA-CN at lag 2 day and 3-day moving average, but negatively related to RTL at lag 0, lag 1 and lag 2 day and 3-day moving average (p < 0.05). Urinary phthalate metabolites were negatively associated with mtDNA lag 0, lag 1 and lag 2 day and 3-day moving average, but positively related to RTL at lag 0 day (p < 0.05). Seasonal factor modified the association of urinary OH-PAHs with mtDNA-CN as well as urinary phthalate metabolites with RTL. In vitro experiment showed that under certain conditions, benzo[a]pyrene increased mtDNA-CN at 48 h and di (2-ethylhexyl) phthalate did RTL at 24 h in HepG2 cells. Seasonal variations in the metabolisms of PAHs or phthalates in human body may affect the relation of PAHs or phthalates exposure with cellular aging
Optimized gas and water production from water-saturated hydrate-bearing sediment through step-wise depressurization combined with thermal stimulation
Sedimentary-volcanic tuffs formed during the early Middle Triassic volcanic event in Guizhou Province and their stratigraphic significance
Current status of diagnosis and treatment of pulmonary hypertension in Chinese tertiary hospitals: A nationwide survey
Abstract We intended to evaluate the diagnosis and treatment status of pulmonary hypertension (PH) in China and provide the basis for the design of the Chinese PH centers system. A questionnaire survey was conducted by sampling from Chinese Class A tertiary hospitals that have carried out the clinical work of PH, including the composition of PH clinical team, the current application of examinations related to PH diagnosis, the availability of PAH‐specific medicine and the implementation of PH‐related intervention and surgery. A total of 44 valid questionnaires from 20 provinces were collected in this survey. In the vast majority of centers (83.33%, n = 35), pulmonary artery catheterization was routinely performed under X‐ray guidance. In 19.05% (n = 8) of centers, pressure measurements were determined at the right time (the end of normal expiration). Only 73.81% (n = 31) centers have carried out acute vasoreactivity testing. Prostacyclin analogues and prostaglandin receptor agonists were just prescribed in 45.45% (n = 20) of the centers. 19 centers (43.18%) were capable of performing balloon pulmonary angioplasty (BPA) and pulmonary endarterectomy (PEA), while 25% (n = 11) were able to perform BPA, PEA, and lung transplantation. There was no significant difference in the diagnosis and treatment of PH between economic regions. The majority of Chinese tertiary hospitals were well equipped with the corresponding personnel, examinations and medicines related to PH, but the standardization and specialization of the management of PH need to be strengthened