Review of micro-scale and atomic-scale corrosion mechanisms of second phases in aluminum alloys

Localized corrosion of aluminum(Al)alloys,such as pitting corrosion,intergranular corrosion,and stress corrosion cracking is closely related to the micro-galvanic corrosion between the second phase and the Al matrix.Using high-resolution transmission electron microscopy and first principles calculations,the factors that affect corrosion mechanisms of the second phase in Al alloys at micro-scale and atomic-scale were examined,including the composition and structure of second phase,pH of the environment,stress and adsorption behavior of adsorbates(such as Cl^(−),H_(2)O,OH−and O_(2)^(−).

Effects of acute kidney injury on acute pancreatitis patients’ survival rate in intensive care unit: A retrospective study

BACKGROUND Acute kidney injury(AKI)is one of the most common acute pancreatitis(AP)-associated complications that has a significant effect on AP,but the factors affecting the AP patients’survival rate remains unclear.AIM To assess the influences of AKI on the survival rate in AP patients.METHODS A total of 139 AP patients were included in this retrospective study.Patients were divided into AKI group(n=72)and non-AKI group(n=67)according to the occurrence of AKI.Data were collected from medical records of hospitalized patients.Then,these data were compared between the two groups and further analysis was performed.RESULTS AKI is more likely to occur in male AP patients(P=0.009).AP patients in AKI group exhibited a significantly higher acute physiologic assessment and chronic health evaluation II score,higher Sequential Organ Failure Assessment score,lower Glasgow Coma Scale score,and higher demand for mechanical ventilation,infusion of vasopressors,and renal replacement therapy than AP patients in non-AKI group(P<0.01,P<0.01,P=0.01,P=0.001,P<0.01,P<0.01,respectively).Significant differences were noted in dose of norepinephrine and adrenaline,duration of mechanical ventilation,maximum and mean values of intra-peritoneal pressure(IPP),maximum and mean values of procalcitonin,maximum and mean serum levels of creatinine,minimum platelet count,and length of hospitalization.Among AP patients with AKI,the survival rate of surgical intensive care unit and in-hospital were only 23%and 21%of the corresponding rates in AP patients without AKI,respectively.The factors that influenced the AP patients’survival rate included body mass index(BMI),mean values of IPP,minimum platelet count,and hospital day,of which mean values of IPP showed the greatest impact.CONCLUSION AP patients with AKI had a lower survival rate and worse relevant clinical outcomes than AP patients without AKI,which necessitates further attention to AP patients with AKI in surgical intensive care unit.

Ischemic preconditioning ameliorates intestinal injury induced by ischemia-reperfusion in rats

AIM: To evaluate preventative effects of ischemic preconditioning(IP) in a rat model of intestinal injury induced by ischemia-reperfusion(IR).METHODS: Male Sprague-Dawley rats(250-300 g) were fasted for 24 h with free access to water prior to the operation.Eighteen rats were randomly divided into three experimental groups: S group(n = 6),rats were subjected to isolation of the superior mesenteric artery(SMA) for 40 min,then the abdomen was closed; IRgroup(n = 6),rats were subjected to clamping the SMA 40 min,and the abdomen was closed followed by a 4-h reperfusion; IP group(n = 6) rats underwent three cycles of 5 min ischemia and 5 min reperfusion,then clamping of the SMA for 40 min,then the abdomen was closed and a 4-h reperfusion followed.All animals were euthanized by barbiturate overdose(150 mg/kg pentobarbital sodium,i.v.) for tissue collection,and the SMA was isolated via median abdominal incision.Intestinal histologic injury was observed.Malondialdehyde(MDA),myeloperoxidase(MPO) and tumor necrosis factor(TNF)-a concentrations in intestinal tissue were measured.Intercellular adhesion molecule(ICAM)-1 and vascular cell adhesion molecule(VCAM)-1 expression,as well as nuclear factor(NF)-κB activity and expression in intestinal tissue were also determined.RESULTS: Compared with the IR group,IP reduced IR-induced histologic injury of the intestine in rats(2.00 ± 0.71 vs 3.60 ± 0.84,P < 0.05).IP significantly inhibited the increase in MDA content(5.6 ± 0.15 μmol/L vs 6.84 ± 0.18 μmol/L,P < 0.01),MPO activity(0.13 ± 0.01 U/L vs 0.24 ± 0.01 U/L,P < 0.01),and TNF-a levels(7.79 ± 2.35 pg/m L vs 10.87 ± 2.48 pg/m L,P < 0.05) in the intestinal tissue of rats.IP also markedly ameliorated the increase in ICAM-1(204.67 ± 53.27 vs 353.33 ± 45.19,P < 0.05) and VCAM-1(256.67 ± 58.59 vs 377.33 ± 41.42,P < 0.05) protein expression in the intestinal tissues.Additionally,IP remarkably decreased NF-κB activity(0.48 ± 0.16 vs 0.76 ± 0.22,P < 0.05) and protein expression(320.23 ± 38.16 vs 520.76 ± 40.53,P < 0.01) in rat intestinal tissue.CONCLUSION: IP may protect against IR-induced intestinal injury by attenuation of the neutrophilendothelial adhesion cascade via reducing ICAM-1 and VCAM-1 expression and TNF-a-induced NF-κB signaling pathway activity.

Induction of apoptosis and cell cycle arrest in human HCC MHCC97H cells with Chrysanthemum indicum extract

AIM： To investigate the effects of Chrysanthemum indicum extract （CIE） on inhibition of proliferation and on apoptosis, and the underlying mechanisms, in a human hepatocellular carcinoma （HCC） MHCC97H cell line. METHODS： Viable rat hepatocytes and human endothelial ECV304 cells were examined by trypan blue exclusion and MTT assay, respectively, as normal controls. The proliferation of MHCC97H cells was determined by MTT assay. The cellular morphology of MHCC97H cells was observed by phase contrast microscopy. Flow cytometry was performed to analyze cell apoptosis with annexin V/propidium iodide （PI）, mitochondrial membrane potential with rhodamine 123 and cell cycle with PI in MHCC97H cells. Apoptotic proteins such as cytochrome C, caspase-9, caspase-3 and cell cycle proteins, including P21 and CDK4, were measured by Western blotting. RESULTS： CIE inhibited proliferation of MHCC97H cells in a timeand dose-dependent manner without cytotoxicity in rat hepatocytes and human endothelial ceils. CIE induced apoptosis of MHCC97H cells in a concentration-dependent manner, as determined by flow cytometry. The apoptosis was accompanied by a decrease in mitochondrial membrane potential, release of cytochrome C and activation of caspase-9 and caspase-3. CIE arrested the cell cycle in the S phase by increasing P21 and decreasing CDK4 protein expression. CONCLUSION： CIE exerted a significant apoptotic effect through a mitochondrial pathway and arrested the cell cycle by regulation of cell cycle-related proteins in MHCC97H cells without an effect on normal cells. The cancer-specific selectivity shown in this study suggests that the plant extract could be a promising novel treatment for human cancer.

Interference of suppressor of cytokine signaling 3 promotes epithelial-mesenchymal transition in MHCC97H cells

AIM:To investigate the role of suppressor of cytokine signaling 3 (SOCS3) silencing in epithelial-mesenchymal transition (EMT) involved in a human hepatocellular carcinoma MHCC97H cell line.METHODS:MHCC97H cells were transiently transfected with SOCS3 small-interfering RNA (siRNA).Morphological changes of the transfected cells were observed under microscope.Expressions of E-cadherin,Vimentinand α-smooth muscle actin (α-SMA) were identified with immunofluorescence.Furthermore,protein expressions and mRNA levels of characteristic markers of EMT (E-cadherin,Vimentin,α-SMA and Snail) were detected by Western blotting,quantitative real-time polymerase chain reaction.Transforming growth factor-β1 (TGF-β1) levels in the supernatant were measured with enzyme-linked immunosorbent assay.RESULTS:The transfected cells with SOCS3 siRNA showed a morphological alteration from a typical cobblestone morphology to mesenchymal spindle-shaped and fusiform features.SOCS3 siRNA lessened immunofluorescent expression of E-cadherin,but elicited immunofluorescent expressions of Vimentin and α-SMA in MHCC97H cells.More importantly,compared with the negative control,depletion of SOCS3 resulted in the decrease of the epithelial marker E-cadherin (P < 0.05),and the increase of the mesenchymal markers Vimentin and α-SMA and the transcription factor Snail in MHCC97H cells (P < 0.05).Moreover,compared with the negative control,SOCS3 siRNA evidently enhanced TGF-β1 secretion in MHCC97H cells (200.20 ± 29.02 pg/mL vs 490.20 ± 92.43 pg/mL,P < 0.05).CONCLUSION:SOCS3 silencing is able to promote EMT in MHCC97H cells via changing the phenotypic characteristics and modulating the characteristic markers.

Role of Reduced Defects for Coupling Reactions of Acetaldehyde on Anatase TiO2（001）-（1×4） Surface

The chemistry of acetaldehyde (CH3CHO) adsorbed on the anatase TiO2(001)-(1×4) surface has been investigated by temperature-programmed desorption (TPD) method. Our experimental results provide the direct evidence that the perfect lattice sites on the anatase TiO2(001)-(1×4) surface are quite inert for the reaction of CH3CHO, but the reduced defect sites on the surface are active for the thermally driven reductive carbon-carbon coupling reactions of CH3CHO to produce 2-butanone and butene. We propose that the coupling reactions of CH3CHO on the anatase TiO2(001)-(1×4) surface should undergo through the adsorption of paired CH3CHO molecules at the reduced defect sites, since the existing reduced Ti pairs provide the suitable adsorption sites.

Molecular subtypes based on DNA methylation predict prognosis in patients with renal clear cell carcinoma

Background:Tumor heterogeneity is closely related to the occurrence,progression and recurrence of renal clear cell carcinoma(ccRCC),making early diagnosis and effective treatment difficult.DNA methylation is an important regulator of gene expression and can affect tumor heterogeneity.Methods:In this study,we investigated the prognostic value of subtypes based on DNA methylation status in 506 ccRCC samples with paired clinical data from the TCGA database.Differences in DNA methylation levels were associated with differences in T,N and M categories,age,stage and prognosis.Finally,the samples were divided into the training group and the testing group according to 450K and 27K.Univariate and multivariate Cox regression analysis was used to construct the prediction model in the training group,and the model was verified and evaluated in the testing group.Results:By univariate Cox regression analysis,21,122 methylation sites and 6,775 CpG sites were identified as potential DNA methylation biomarkers for overall survival of ccRCC patients(P<0.05).3,050 CpG sites independently associated with prognosis were identified with T,N,M,stage and age as covariables.Consensus cluster of 3,050 potential prognostic methylation sites was used to identify different DNA methylation subsets of ccRCC for prognostic purposes.We performed functional enrichment analysis on these 3,640 genes and identified 75 significantly enriched pathways(P<0.05).We then researched the expression of methylated genes in subgroups.Verifing with the training set,suggesting that DNA methylation levels generally reflect the expression of these genes.Conclusion:Based on TCGA database and a series of bioinformatics methods,We identified prognostic specific methylation sites and established prognostic prediction models for ccRCC patients.This model helps to identify novel biomarkers,precision drug targets and disease molecular subtypes in patients with ccRCC.Therefore,this model may be useful in predicting the prognosis,clinical diagnosis and management of patients with different epigenetic subtypes of ccRCC.

Potentiation of the lateral habenula-ventral tegmental area pathway underlines the susceptibility to depression in mice with chronic pain

Chronic pain often develops severe mood changes such as depression.However,how chronic pain leads to depression remains elusive and the mechanisms determining individuals’responses to depression are largely unexplored.Here we found that depression-like behaviors could only be observed in 67.9%of mice with chronic neuropathic pain,leaving 32.1%of mice with depression resilience.We determined that the spike discharges of the ventral tegmental area(VTA)-projecting lateral habenula(LHb)glutamatergic(Glu)neurons were sequentially increased in sham,resilient and susceptible mice,which consequently inhibited VTA dopaminergic(DA)neurons through a LHbGlu-VTAGABA-VTADA circuit.Furthermore,the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic manner.Regulation of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic pain.Our study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.

Cofitness network connectivity determines a fuzzy essential zone in open bacterial pangenome

Most in silico evolutionary studies commonly assumed that core genes are essential for cellular function,while accessory genes are dispensable,particularly in nutrient-rich environments.However,this assumption is seldom tested genetically within the pangenome context.In this study,we conducted a robust pangenomic Tn-seq analysis of fitness genes in a nutrient-rich medium for Sinorhizobium strains with a canonical open pangenome.To evaluate the robustness of fitness category assignment,Tn-seq data for three independent mutant libraries per strain were analyzed by three methods,which indicates that the Hidden Markov Model(HMM)-based method is most robust to variations between mutant libraries and not sensitive to data size,outperforming the Bayesian and Monte Carlo simulation-based methods.Consequently,the HMM method was used to classify the fitness category.Fitness genes,categorized as essential(ES),advantage(GA),and disadvantage(GD)genes for growth,are enriched in core genes,while nonessential genes(NE)are over-represented in accessory genes.Accessory ES/GA genes showed a lower fitness effect than core ES/GA genes.Connectivity degrees in the cofitness network decrease in the order of ES,GD,and GA/NE.In addition to accessory genes,1599 out of 3284 core genes display differential essentiality across test strains.Within the pangenome core,both shared quasi-essential(ES and GA)and strain-dependent fitness genes are enriched in similar functional categories.Our analysis demonstrates a considerable fuzzy essential zone determined by cofitness connectivity degrees in Sinorhizobium pangenome and highlights the power of the cofitness network in understanding the genetic basis of ever-increasing prokaryotic pangenome data.