Study on corrosion resistance of Portland cement-calcium sulphoaluminate cement binary system in a sodium chloride environment

Portland cement is widely used in civil engineering. However, Portland cement-based materials are easy to be corroded by seawater in marine environment. Many research show the corrosion resistance of Portland cement mortar can be improved by add appropriate amount of mineral admixture.Sulphoaluminate cement have high strength and good corrosion seawater resistance. However, the short setting time and high hydration heat of sulphoaluminate cement limit its application in civil engineering.Portland cement-sulphoaluminate cement (PC-CSA) not only have high strength and corrosion resistance but also long setting time.In this work, the sulphoaluminate cement was used to partially replace Portland cement. The replacement level of sulphoaluminate cement was 10 %, 20 % and 30 % by weight of Portland cement. Mortar specimens was soaked in sodium chloride solution under standard curing after 28 days. The concentration of sodium chloride solution was 3.5wt %. Mechanical properties , corrosion resistance and setting time of PC-CSA binary system were tested in the research. The hydration behavior of binary system was determined by isothermal calorimetry and X-ray diffraction methods. Microstructure of the binary system at different ages were analyzed by scanning electron microscope. The strength of PC-CSA binary system was tested at different curing ages up to 28 days.The results show when replacement level of sulphoaluminate cement is 20%, the comprehensive strength up to 50MPa and higher than other groups at 28 days soaked in corrosion solution.when replacement level of sulphoaluminate cement is 20%,the corrosion resistance is best,and penetration depth of chloride ions is the least

Modeling Occupant Window Behavior in Hospitals—A Case Study in a Maternity Hospital in Beijing, China

Nowadays, relevant data collected from hospital buildings remain insufficient because hospital buildings often have stricter environmental requirements resulting in more limited data access than other building types. Additionally, existing window-opening behavior models were mostly developed and validated using data measured from the experimental building itself. Hence, their accuracy is only assessed by the algorithm’s evaluation index, which limits the model’s applicability, given that it is not tested by the actual cases nor cross-verified with other buildings. Based on the aforementioned issues, this study analyzes the window-opening behavior of doctors and patients in spring in a maternity hospital in Beijing and develops behavioral models using logistic regression. The results show that the room often has opened windows in spring when the outdoor temperature exceeds 20 °C. Moreover, the ward windows’ use frequency is more than 10 times higher than those of doctors’ office. The window-opening behavior in wards is more susceptible to the influence of outdoor temperature, while in the doctors’ office, more attention is paid to indoor air quality. Finally, by embedding the logistic regression model of each room into the EnergyPlus software to simulate the CO2 concentration of the room, it was found that the model has better applicability than the fixed schedule model. However, by performing cross-validation with different building types, it was found that, due to the particularity of doctors’ offices, the models developed for other building types cannot accurately reproduce the window-opening behavior of doctors. Therefore, more data are still needed to better understand window usage in hospital buildings and support the future building performance simulations of hospital buildings

Effect of acetone extract of Rumex japonicas Houtt on hydrogen peroxide-induced apoptosis in rat myocardial cells

Purpose: To investigate the protective effect of the acetone extract of Rumex japonicas Houtt. (AER) on rat myocardial cells.Methods: R. japonicas was extracted with 75 % aqueous ethanol by reflux to afford total extract (TER). TER was suspended in water and then extracted with acetone to afford acetone fraction of R. japonicas (AER). High performance liquid chromatography (HPLC) combined with standard substances was carried out to analyze the major constituents of AER. Apoptosis in myocardial H9c2 cell line was induced by H2O2 (100 μmol/L). The cells were treated with AER (50, 100 and 200 μg/mL, and cell viability was evaluated by the 3-（4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, while oxidative stress level in H9c2 cells was evaluated by determining levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), creatinine kinase (CK), superoxide dismutase (SOD), and catalase (CAT). Furthermore, apoptotic proteins (caspase-3, Bax and Bcl-2) in H9c2 cells were analyzed by using western blot assay.Results: Results revealed that the main components of AER are aloe-emodin, rhein, emodin, chrysophanol and physcion. AER (50, 100 and 200 μg/mL) inhibited the cell viability reduction of the H9c2 cells induced by H2O2 (p < 0.05, p < 0.01, p < 0.01, respectively). AER (50, 100 and 200 μg/mL) decreased LDH and CK contents of H9c2 cells (p < 0.01). The levels of SOD (p<0.01) and CAT (p < 0.01) were increased by AER treatments (100 and 200 μg/mL); in addition, AER (50, 100 and 200 μg/mL) decreased MDA levels (p < 0.01). Besides, the present results also revealed that AER could down-regulate caspase-3 and Bax, but up-regulated Bcl-2.Conclusion: AER alleviates apoptosis induced by H2O2 in myocardial H9c2 cells via inhibition of oxidative stress and mitochondria-mediated apoptosis. This finding suggests that AER can potentially be developed for the treatment of myocardial apoptosis.Keywords: Rumex japonicas Houtt., Myocardial cells, Apoptosis, H9c2 cell, Oxidative stres

Hydrogen sulfide inhibits the renal fibrosis of obstructive nephropathy

Hydrogen sulfide has recently been found decreased in chronic kidney disease. Here we determined the effect and underlying mechanisms of hydrogen sulfide on a rat model of unilateral ureteral obstruction. Compared with normal rats, obstructive injury decreased the plasma hydrogen sulfide level. Cystathionine-β-synthase, a hydrogen sulfide-producing enzyme, was dramatically reduced in the ureteral obstructed kidney, but another enzyme cystathionine-γ-lyase was increased. A hydrogen sulfide donor (sodium hydrogen sulfide) inhibited renal fibrosis by attenuating the production of collagen, extracellular matrix, and the expression of α-smooth muscle actin. Meanwhile, the infiltration of macrophages and the expression of inflammatory cytokines including interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in the kidney were also decreased. In cultured kidney fibroblasts, a hydrogen sulfide donor inhibited the cell proliferation by reducing DNA synthesis and downregulating the expressions of proliferation-related proteins including proliferating cell nuclear antigen and c-Myc. Further, the hydrogen sulfide donor blocked the differentiation of quiescent renal fibroblasts to myofibroblasts by inhibiting the transforming growth factor-β1-Smad and mitogen-activated protein kinase signaling pathways. Thus, low doses of hydrogen sulfide or its releasing compounds may have therapeutic potentials in treating chronic kidney disease

Effects of repetitive transcranial magnetic stimulation on episodic memory in patients with subjective cognitive decline: study protocol for a randomized clinical trial

IntroductionEarly decline of episodic memory is detectable in subjective cognitive decline (SCD). The left dorsolateral prefrontal cortex (DLPFC) is associated with encoding episodic memories. Repetitive transcranial magnetic stimulation (rTMS) is a novel and viable tool to improve cognitive function in Alzheimer’s disease (AD) and mild cognitive impairment, but the treatment effect in SCD has not been studied. We aim to investigate the efficacy of rTMS on episodic memory in individuals with SCD, and to explore the potential mechanisms of neural plasticity.MethodsIn our randomized, sham-controlled trial, patients (n = 60) with SCD will receive 20 sessions (5 consecutive days per week for 4 weeks) of real rTMS (n = 30) or sham rTMS (n = 30) over the left DLPFC. The primary outcome is the Auditory Verbal Learning Test-Huashan version (AVLT-H). Other neuropsychological examinations and the long-term potentiation (LTP)-like cortical plasticity evaluation serve as the secondary outcomes. These outcomes will be assessed before and at the end of the intervention.DiscussionIf the episodic memory of SCD improve after the intervention, the study will confirm that rTMS is a promising intervention for cognitive function improvement on the early stage of dementia. This study will also provide important clinical evidence for early intervention in AD and emphasizes the significance that impaired LTP-like cortical plasticity may be a potential biomarker of AD prognosis by demonstrating the predictive role of LTP on cognitive improvement in SCD.Ethics and disseminationThe study was approved by the Human Research Ethics Committee of the hospital (No. 2023-002-01). The results will be published in peer-review publications.Clinical trial registrationhttps://www.chictr.org.cn/, identifier ChiCTR2300075517

Characterisation of the phenanthrene degradation-related genes and degrading ability of a newly isolated copper-tolerant bacterium

A copper-tolerant phenanthrene (PHE)-degrading bacterium, strain Sphingobium sp. PHE-1, was newly isolated from the activated sludge in a wastewater treatment plant. Two key genes, ahdA1b-1 encoding polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHDɑ) and xyLE encoding catechol-2,3-dioxygenase (C23O), involved in the PHE metabolism by strain PHE-1 were identified. The PAH-RHD gene cluster showed 96% identity with the same cluster of Sphingomonas sp. P2. Our results indicated the induced transcription of xylE and ahdA1b-1 genes by PHE, simultaneously promoted by Cu(II). For the first time, high concentration of Cu(II) is found to encourage the expression of PAH-RHDɑ and C23O genes during PHE degradation. Applying Sphingomonas PHE-1 in PHE-contaminated soils for bioaugmentation, the abundance of xylE gene was increased by the planting of ryegrass and the presence of Cu(II), which, in turn, benefited ryegrass growth. The best performance of PHE degradation and the highest abundance of xylE genes occurred in PHE-copper co-contaminated soils planted with ryegrass