Acute kidney injury （AKI） and chronic kidney disease （CKD） are worldwide public health problems affecting millions of people and have rapidly increased in prevalence in recent years. Due to the multiple causes of ...Acute kidney injury （AKI） and chronic kidney disease （CKD） are worldwide public health problems affecting millions of people and have rapidly increased in prevalence in recent years. Due to the multiple causes of renal failure, many animal models have been developed to advance our understanding of human nephropathy. Among these experimental models, rodents have been extensively used to enable mechanistic understanding of kidney disease induction and progression, as well as to identify potential targets for therapy. In this review, we discuss AKI models induced by surgical operation and drugs or toxins, as well as a variety of CKD models （mainly genetically modified mouse models）. Results from recent and ongoing clinical trials and conceptual advances derived from animal models are also explored.展开更多
The effect of Er on the microhardness and precipitation behavior of the heat-treated Al−Si−Mg alloy was investigated by microhardness tester and TEM.As a comparison,the influence of natural aging was also studied.It i...The effect of Er on the microhardness and precipitation behavior of the heat-treated Al−Si−Mg alloy was investigated by microhardness tester and TEM.As a comparison,the influence of natural aging was also studied.It is shown that the thermal stability of the over-aged Al−Si−Mg−Er alloy is highly related to the average size of the precipitates.The average size ofβ''precipitates in Al−Si−Mg−Er alloy is smaller than that in Al−Si−Mg alloy,and the distribution is more localized under condition of without introducing natural aging.However,when natural aging is introduced before artificial aging,the Al−Si−Mg−Er alloy has similar average size and distribution of precipitates with the Al−Si−Mg alloy,resulting in similar mechanical properties.The effect of Er on the precipitation kinetics in the alloy was also discussed in detail to explain these phenomena.展开更多
The anomalous flow behavior of γ'-Ni_(3)Al phases at high temperature is closely related to the cross-slip of 1/2<110>{111}super-partial dislocations.Generalized stacking fault energy curves(i.e.,Γ-surface...The anomalous flow behavior of γ'-Ni_(3)Al phases at high temperature is closely related to the cross-slip of 1/2<110>{111}super-partial dislocations.Generalized stacking fault energy curves(i.e.,Γ-surfaces)along the lowest energy path can provide a great deal of information on the nucleation and movement of dislocations.With the first-principles calculation,the interplay between Re and W,Mo,Ta,Ti doped at preferential sites and their synergetic influence on Γ-surfaces and ideal shear strength(τ_(max))in γ'-Ni_(3)Al phases are investigated.Similar to single Re-addition,the Suzuki segregation of W at stacking faults is demonstrated to enable to impede the movement of 1/6<112>{111} Shockley partial dislocations and promote the cross-slip of 1/2<110>{111}super-partial dislocations.With the replacement of a part of Re by W,a decreased γ_(APB)^(111)/γ_(APB)^(001) indicates that the anomalous flow behavior of γ'phases at high temperature is not as excellent as the double Re-addition,but an increasedτmax means that the creep rupture strength of Ni-based single crystal superalloys can be benefited from this replacement to some extent,especially in the co-segregation of Re and W at Al−Al sites.As the interaction between X1_(Al) and X2_(Al) point defects is characterized by an correlation energy function ΔE^(X1_(Al)+X2_(Al))(d),it is found that both strong attraction and strong repulsion are unfavarable for the improvement of yield strengths of γ'phase.展开更多
BACKGROUND Antiviral drugs are widely used in populations with viral infection caused by immunologic inadequacy.Because these drugs are mainly metabolized by the kidneys,patients with renal failure undergoing renal re...BACKGROUND Antiviral drugs are widely used in populations with viral infection caused by immunologic inadequacy.Because these drugs are mainly metabolized by the kidneys,patients with renal failure undergoing renal replacement therapy are prone to drug adverse effects and poisoning.Severe neurotoxicity caused by antiviral drugs is a rare but life-threatening complication.CASE SUMMARY This study reported one male patient on peritoneal dialysis who suffered from severe mental disorders after receiving an overdose of acyclovir and valacyclovir for the treatment of herpes zoster.The literature review suggested that hemodialysis is better than peritoneal dialysis to clear acyclovir from the circulation.The patient died after his consciousness deteriorated despite peritoneal dialysis and continuous blood purification.CONCLUSION This case emphasizes cautiousness when using anti-retroviral drugs in patients with uremia.Hemodialysis is optimal method to remove the drugs.展开更多
1 Introduction Chronic kidney disease(CKD)often coexists with or is a complication of cardiovascular disease.Previous studies have shown that CKD increases the risk of cardiovascular death and all-cause death and was ...1 Introduction Chronic kidney disease(CKD)often coexists with or is a complication of cardiovascular disease.Previous studies have shown that CKD increases the risk of cardiovascular death and all-cause death and was considered to be a risk equivalent of coronary heart disease.[1,2]Adjusted for confounders,decreased glomerular filtration rate(GFR)and increased albuminuria are both independent risk factors for cardiovascular events.[3,4]The risk for cardiovascular death linearly increases with the decline of GFR in a certain range(<70 mL/min per 1.73 m^2)and the increase of albuminuria without a threshold effect[3].展开更多
Background： High peritoneal transport status was previously thought to be a poor prognostic factor in peritoneal dialysis （PD） patients. However, its effect on diabetic nephropathy PD patients is unclear in conside...Background： High peritoneal transport status was previously thought to be a poor prognostic factor in peritoneal dialysis （PD） patients. However, its effect on diabetic nephropathy PD patients is unclear in consideration of the adverse impact of diabetes itself. The purpose of this study was to investigate the influence of peritoneal transport characteristics on nutritional status and clinical outcome in diabetic nephropathy patients on PD. Methods： One hundred and two diabetic nephropathy patients on PD were enrolled in this observational cohort study. According to the initial peritoneal equilibration test result, patients were divided into two groups： Higher transport group （HT, including high and high average transport） and lower transport group （LT, including low and low-average transport）. Demographic characteristics, biochemical data, dialysis adequacy, and nutritional status were evaluated. Clinical outcomes were compared. Risk factors for death-censored technique failure and mortality were analyzed. Results： Compared with LT group （n = 37）, serum albumin was significantly lower and the incidence of malnutrition by subjective global assessment was significantly higher in HT group （n = 65） （P 〈 0.05）. Kaplan-Meier analyses showed that death-censored technique failure and mortality were significantly increased in HT group compared with that in LT group. On multivariate Cox analyses, higher peritoneal transport status and lower residual renal function （RRF） were independent predictors of death-censored technique failure when adjusted for serum albumin and total weekly urea clearance （Kt/V）. Independent predictors of mortality were advanced age, anemia, hypoalbuminemia, and lower RRF, but not higher peritoneal transport status. Conclusions： Higher peritoneal transport status has an adverse influence on nutrition for diabetic nephropathy patients on PD. Higher peritoneal transport status is a significant independent risk factor for death-censored technique failure, but not for mortality in diabetic nephropathy patients on PD.展开更多
Background and aims： Ingestion of paraquat （PQ）, a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul-...Background and aims： Ingestion of paraquat （PQ）, a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul- monary fibrosis, for which there are no effective therapies. The aim of this study was to evaluate the effects of ra- pamycin （PAPA） on inhibiting PQ-induced pulmonary fibrosis in mice and to explore its possible mechanisms. Methods： Male C57BL/6J mice were exposed to either saline （control group） or PQ （10 mg/kg body weight, intraper- itoneally; test group）. The test group was divided into four subgroups： a PQ group （PQ-exposed, non-treated）, a PQ＋RAPA group （PQ-exposed, treated with RAPA at I mg/kg intragastrically）, a PQ＋MP group （PQ-exposed, treated with methylprednisolone （MP） at 30 mg/kg intraperitoneally）, and a PQ＋MP＋RAPA group （PQ-exposed, treated with MP at 30 mg/kg intraperitoneally and with PAPA at 1 mg/kg intragastrically）. The survival rate and body weight of all the mice were recorded every day. Three mice in each group were sacrificed at 14 d and the rest at 28 d after intox- ication. Lung tissues were excised and stained with hematoxylin-eosin （H＆E） and Masson＇s trichrome stain for his- topathological analysis. The hydroxyproline （HYP） content in lung tissues was detected using an enzyme-linked im- munosorbent assay （ELISA） kit. The expression of transforming growth factor-β1 （TGF-β1） and α-smooth muscle actin （α-SMA） in lung tissues was detected by immunohistochemical staining and Western blotting. Results： A mice model of PQ-induced pulmonary fibrosis was established. Histological examination of lung tissues showed that PAPA treatment moderated the pathological changes of pulmonary fibrosis, including alveolar collapse and interstitial collagen depo- sition. HYP content in lung tissues increased soon after PQ intoxication but had decreased significantly by the 28th day after PAPA treatment. Immunohistochemical staining and Western blotting showed that PAPA treatment significantly down-regulated the enhanced levels of TGF-β1 and e-SMA in lung tissues caused by PQ exposure. However, PAPA treatment alone could not significantly ameliorate the lower survival rate and weight loss of treated mice. MP treatment enhanced the survival rate, but had no significant effects on attenuating PQ-induced pulmonary fibrosis or reducing the expression of TGF-β1 and a-SMA. Conclusions： This study demonstrates that PAPA treatment effectively suppresses PQ-induced alveolar collapse and collagen deposition in lung tissues through reducing the expression of TGF-β1 and a-SMA. Thus, RAPA has potential value in the treatment of PQ-induced pulmonary fibrosis.展开更多
Objective： The treatment of Henoch-Schonlein purpura （HSP） with moderate proteinuria remains con- troversial. We retrospectively analyzed the efficacy of immune suppressants, with a particular emphasis on myco- phe...Objective： The treatment of Henoch-Schonlein purpura （HSP） with moderate proteinuria remains con- troversial. We retrospectively analyzed the efficacy of immune suppressants, with a particular emphasis on myco- phenolate mofetil （MMF）. Methods： Ninety-five HSP patients with moderate proteinuria （1.0-3.5 g/24 h） after at least three months of therapy with angiotensin-converting enzyme inhibitor （ACEI） or angiotensin receptor blocker （ARB） were divided into three groups： an MMF group （n=33） that received MMF 1.0-1.5 g/d combined with prednisone （0.4-0.5 mg/（kg.d））, a corticosteroid （CS） group （n=31） that received full-dose prednisone （0.8-1.0 mg/（kg.d））, and a control group （n=31）. Patients in the MMF and CS groups continued to take ACEI or ARB at the original dose. The patients in the control group continued to take ACEI or ARB but the dose was increased by （1.73±0.58）-fold. The patients were followed up for 6-78 months （median 28 months）. Results： The baseline proteinuria was higher in the MMF group （（2.1±0.9） g/24 h） than in the control group （（1.6±0.8） g/24 h） （P=0.039）. The proteinuria decreased sig- nificantly in all groups during follow-up, but only in the MMF group did it decrease significantly after the first month. At the end of follow-up, the proteinuria was （0.4±0.7） g/24 h in the MMF group and （0.4±0.4） g/24 h in the CS group, significantly lower than that in the control group （（0.9±1.1） g/24 h）. The remission rates in the MMF group, CS group, and control group were respectively 72.7%, 71.0%, and 48.4% at six months and 72.7%, 64.5%, and 45.2% at the end of follow-up. The overall number of reported adverse events was 17 in the MMF group, 30 in the CS group, and 6 in the control group （P〈0.001）. Conclusions： MMF with low-dose prednisone may be as effective as full-dose prednisone and tend to have fewer adverse events. Therefore, it is probably superior to conservative treatments of adult HSP patients with moderate proteinuria.展开更多
Radix Sophorae tonkinensis(RST) is a widely used herb in Traditional Chinese Medicine(TCM) for treating infectious and inflammatory diseases. However, the toxicity data for RST are limited. The aim of this work is to ...Radix Sophorae tonkinensis(RST) is a widely used herb in Traditional Chinese Medicine(TCM) for treating infectious and inflammatory diseases. However, the toxicity data for RST are limited. The aim of this work is to assess and compare the toxicity of the whole RST extract and its five active fractions using the zebrafish model. Five active fractions of RST were prepared using five different types of solvents, which included dealkalized water, ethanol, n-butyl ethanol, dichloromethane, and diethyl ether. The chemical profiles of the active fractions were determined by high-performance liquid chromatography(HPLC), and the toxicity observed in the zebrafish model was confirmed using mouse models. In the zebrafish model, cardiovascular toxicity was observed for the fraction extracted using diethyl ether, and hepatotoxicity was observed for the whole RST extract and the fractions extracted using water and ethanol, whereas both cardiovascular and hepatic toxicities were observed for the fractions extracted using n-butyl ethanol and dichloromethane. The hepatotoxicity of the fractions extracted using n-butyl ethanol and dichloromethane was also observed in mice. Our findings provide the toxicity data for RST and its five active fractions through modeling in a zebrafish, and indicate that the different fractions may each have a different toxicity, which is helpful for the optimal use of RST in clinical practice.展开更多
The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron...The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron microscopy in association with first-principles energy calculations, we systematically studied the complex coexisting precipitates in the alloys and correlated their precipitation sequences with thermal ageing processes applied. The principal results are the following： （1） eight types of precipitates can be observed in the alloy; （2） of these precipitates, the Tl-phase is most stable. The S-phase precipitates with segregated Li atoms at their interfacial edges are unexpectedly more stable than the a-phase; （3） the Tl-phase has a characteristic precursor that plays the key role in its nucleation and growth.展开更多
Pre-deformation before aging has been demonstrated to have a positive effect on the mechanical strength of the 7N01 alloy in our previous study,which is rather different from the general negative effects of pre-deform...Pre-deformation before aging has been demonstrated to have a positive effect on the mechanical strength of the 7N01 alloy in our previous study,which is rather different from the general negative effects of pre-deformation on high-strength 7XXX aluminum alloys.In order to explain the strengthening mechanism relating to the positive effect,in the present study,the microstructure of the aged 7N01 alloy with different degrees of pre-deformation was investigated in detail using advanced electron microscopy techniques.Our results show that,without pre-deformation,the aged alloy is strengthened mainly by the η′type of hardening precipitates.In contrast,with pre-deformation,the aged alloy is strengthened by the hierarchical microstructure consisting of the GP-η′type of precipitates formed inside sub-grains,the ηp type of precipitates formed at small-angle boundaries,and the dislocation introduced by pre-deformation(residual work-hardening effect).By visualizing the distribution of theηp precipitates through three-dimensional electron tomography,the 3 D microstructures of dislocation cells are clearly revealed.Proper combinations of ηp precipitates,GP-η′precipitates and residual dislocations in the alloy are responsible for the positive effect of pre-deformation on its mechanical properties.展开更多
The purpose of this review is to objectively evaluate the biochemical and pathophysiological properties of 0.9% saline （henceforth： saline） and to discuss the impact of saline infusion, specifically on systemic aci...The purpose of this review is to objectively evaluate the biochemical and pathophysiological properties of 0.9% saline （henceforth： saline） and to discuss the impact of saline infusion, specifically on systemic acid-base bal- ance and renal hemodynamics. Studies have shown that electrolyte balance, including effects of saline infusion on serum electrolytes, is often poorly understood among practicing physicians and inappropriate saline prescribing can cause increased morbidity and mortality. Large-volume （〉2 L） saline infusion in healthy adults induces hyperohloremia which is associated with metabolic acidosis, hyperkalemia, and negative protein balance. Saline overload （80 ml/kg） in rodents can cause intestinal edema and contractile dysfunction associated with activation of sodium-proton exchanger （NHE） and decrease in myosin light chain phosphorylation. Saline infusion can also adversely affect renal hemody- namics. Microperfusion experiments and real-time imaging studies have demonstrated a reduction in renal perfusion and an expansion in kidney volume, compromising 02 delivery to the renal perenchyma following saline infusion. Clinically, saline infusion for patients post abdominal and cardiovascular surgery is associated with a greater number of adverse effects including more frequent blood product transfusion and bicarbonate therapy, reduced gastric blood flow, delayed recovery of gut function, impaired cardiac contractility in response to inotropes, prolonged hospital stay, and possibly increased mortality. In critically ill patients, saline infusion, compared to balanced fluid infusions, in- creases the occurrence of acute kidney injury. In summary, saline is a highly acidic fluid. With the exception of saline infusion for patients with hypochloremic metabolic alkalosis and volume depletion due to vomiting or upper gastroin- testinal suction, indiscriminate use, especially for acutely ill patients, may cause unnecessary complications and should be avoided. More education regarding saline-related effects and adequate electrolyte management is needed.展开更多
Intrinsic stacking-fault energy is a critical parameter influencing the various mechanical performances of aus- tenitic steels with high Mn concentrations. However, quantitative calculations of the stacking-fault ener...Intrinsic stacking-fault energy is a critical parameter influencing the various mechanical performances of aus- tenitic steels with high Mn concentrations. However, quantitative calculations of the stacking-fault energy （SFE） of the face-centered cubic （fcc） Fe, including the changes in concentrations and geometrical distribution of alloying atoms, cannot be obtained by using previous computation models. On the basis of the interaction energy model, we evaluated the effects of a single alloying atom （i.e., Mn, A1, Si, C and N）, as well as its aggregates, including the Mn-X dimer and Mn2-X trimer （X = A1, Si, C and N） on the SFE of the fcc Fe via first-principle calculations. Given low concentrations （〈10 wt%） of alloying atoms, dimers and trimers, theoretical calculations reveal the following： （1） Alloying atom Mn causes a decrease in the SFE, whereas A1, Si, C and N significantly increase the SFE; （2） combination with other alloying atoms to form the Mn-X dimer （X = A1, Si, C and N） exerts an effect on SFE that, to a certain extent, is close to that of the corresponding single X atom; （3） the interaction between Mnz-X and the stacking fault is stronger than that of the corresponding single X atom, inducing a significant increase in the SFE of fcc Fe. The theoretical results we obtained demonstrate that the increase in SFE in high-Mn steel originates from the synergistic effect of Mn and other trace alloy atoms.展开更多
Enhancing combinatorial properties,such as excellent corrosion resistance,high strength and good ductility combined,is an important issue for manufacturing high-quality AlMgSi(Cu)alloys.Here,we show that this can be a...Enhancing combinatorial properties,such as excellent corrosion resistance,high strength and good ductility combined,is an important issue for manufacturing high-quality AlMgSi(Cu)alloys.Here,we show that this can be achieved by optimizing a combinatorial process consisting of pre-ageing,cold-rolling and post-ageing to tailor the hierarchical microstructures of the alloy.Transmission electron microscopy analysis reveals that the enhanced combinatorial properties of corrosion resistance,strength and ductility are owing to modification of grain boundary microstructure in good association with changes of precipitate microstructures and a more homogenous distribution of solute atoms,as compared with the microstructures of the alloy processed by thermal ageing only.展开更多
Objective： To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs （NSAIDs） in renal ischemia-reperfusion injury （IRI） and the cyclooxygenase （COX）-1/2 blockade association by indomethac...Objective： To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs （NSAIDs） in renal ischemia-reperfusion injury （IRI） and the cyclooxygenase （COX）-1/2 blockade association by indomethacin （IMT） in the mice model. Methods： After the left renal pedicle of mice was clamped, IMT was administrated by intraperitoneal injection with four doses： 1, 3, 5, and 7 mg/kg. Blood and kidney samples were collected 24 h after IRI. The renal functions were assayed by the cytokines and serum creatinine （SCr） using enzyme-linked immunosorbent assay （ELISA） kits. Kidney samples were analyzed by hematoxylin and eosin （H＆E） and immunohistochemistry stainings. Results： The mice administered with 5 mg/kg IMT had a marked reduction in SCr and significantly less tubular damage The tumor necrosis factor a （TNF-α） activity in renal homogenates and interleukin 6 （IL-6） activity in serum had a marked reduction at doses of 5 and 7 mg/kg IMT. The administration of 3 and 5 mg/kg IMT had a marked reduction in the ratio of thromboxane B2 to 6-keto-prostaglandin F1α. COX-1 and COX-2 stainings were weaker in 5 mg/kg IMT groups than that in the other groups. Conclusions： There was a dose response in the IMT function of renal IRI in mice, and IMT had a protective effect in a certain dose range. The effect of IMT on mice IRI was related to COX-1/2 blockades.展开更多
The formation of highly coherent double-shelled L1_(2) nano-precipitates in dilute Al–Er–Sc–Zr alloys was investigated with the combined use of Cs-corrected transmission electron microscopy characterization and fir...The formation of highly coherent double-shelled L1_(2) nano-precipitates in dilute Al–Er–Sc–Zr alloys was investigated with the combined use of Cs-corrected transmission electron microscopy characterization and first-principles energetics calculations. The double-shelled nano-precipitates are primarily featured with an Er-rich core surrounded by a Sc-rich inner shell and a Zr-rich outer shell. First-principles energetics analyses based on the classic homogenous nucleation theory suggested that once forms, this double-shell structure can be thermally stable. The predominant formation of this double-shell structure has thus both profound kinetic and thermodynamic origins. Its formation and stability preference to all other possible L1_(2) nano-structures would become more pronounced as its size increases, no matter what the solute ratio and aging temperature of interest.展开更多
Owing to the excellent elastic properties and chemical stability,binary metal or light element borides,carbides and nitrides have been extensively applied as hard and low-compressible materials.Researchers are searchi...Owing to the excellent elastic properties and chemical stability,binary metal or light element borides,carbides and nitrides have been extensively applied as hard and low-compressible materials.Researchers are searching for harder materials all the time.Recently,the successful fabrication of nano-twinned cubic BN(Tian et al.Nature 493:385–388,2013)and diamond(Huang et al.Nature 510:250–253,2014)exhibiting superior properties than their twin-free counterparts allows an efficient way to be harder.From this point of view,the borides,carbides and nitrides may be stronger by introducing twins,whose formation tendency can be measured using stacking fault energies(SFEs).The lower the SFEs,the easier the formation of twins.In the present study,by means of first-principles calculations,we first calculated the fundamental elastic constants of forty-two borides,seventeen carbides and thirty-one nitrides,and their moduli,elastic anisotropy factors and bonding characters were accordingly derived.Then,the SFEs of the{111}<112>glide system of twenty-seven compounds with the space group F43 m or Fm3m were calculated.Based on the obtained elastic properties and SFEs,we find that(1)light element compounds usually exhibit superior elastic properties over the metal borides,carbides or nitrides;(2)the 5 d transitionmetal compounds(ReB2,WB,OsC,RuC,WC,OsN2,TaN and WN)possess comparable bulk modulus(B)with that of cBN(B=363 GPa);(3)twins may form in ZrB,HfN,PtN,VN and ZrN,since their SFEs are lower or slightly higher than that of diamond(SFE=277 mJ/m^2).Our work can be used as a valuable database to compare these compounds.展开更多
Mechanical theories show that properties of alloys are strongly dependent on the morphological parameters oftheir strengthening precipitates.However,accurate measurement of precipitates microstructure parameters is st...Mechanical theories show that properties of alloys are strongly dependent on the morphological parameters oftheir strengthening precipitates.However,accurate measurement of precipitates microstructure parameters is still a challenging task.In this article,we develop a quantitative electron tomography method by combining computer vision technology to accurately characterize the three-dimensional microstructure parameters,such as volume fractions,sizes and distributions,of the T_(1) and δ’/θ’/δ’ precipitates in Al-Cu-Li(-Mg) alloys.Since they have extremely large aspect-ratios in shape and large numbers in density upon formation in the Al matrix,these thin plate-like precipitates are difficult to be characterized quantitatively without the assistance of computer vision technology.It is shown that the property difference between two peak-aged states of the alloy can be well explained with the quantitative precipitate parameters correctly measured.Using these correct precipitate data,we also tested the validity of current mechanical models for projecting the contribution of precipitates to the strengths of the alloy,demonstrating that quantitative relations between strength and micro structure parameters still need to be refined.展开更多
Three types of symmetric （1120） tilt low-angle grain boundaries （LAGBs） with array of basal, prismatic, and pyramidal edge full 〈a〉 dislocations in pure Mg have been studied by using the improved Peierls-Nabarro...Three types of symmetric （1120） tilt low-angle grain boundaries （LAGBs） with array of basal, prismatic, and pyramidal edge full 〈a〉 dislocations in pure Mg have been studied by using the improved Peierls-Nabarro model in combination with the generalized stacking fault energy curve. The results show that with decreasing distance between the dislocations in all the three types of tilt LAGBs, the stress and strain fields are gradually suppressed. The reduction extent of the stress and strain fields decreases from the prismatic to basal to pyramidal dislocations. The variation of dislocation line energy （DLE） for all tilt LAGBs is divided into three stages： DLE changes slightly and linearly when the distance is larger than 300 A, - 10%; DLE declines exponentially and quickly when the distance goes from 300 to 100 A, ,- 70%; and finally, the descent speed lowers when the distance is smaller than 100 A and the dislocation core energy is nearly half of the DLE. The grain boundary energy （GBE） decreases when the tilt angle of LAGB increases from1 ° to 2° for all cases. The tilt LAGB consists of pyramidal dislocations always has the largest GBE, while that with array of prismatic dislo- cations has the smallest one in the whole range. The Peierls stress of dislocation in tilt LAGB is nearly unchanged, the same as that of single dislocation. This work is useful for further study of dissociated dislocation, solute segregation, precipitate nucleation in tilt LAGB and its interaction with single dislocations.展开更多
We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this stud...We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this study, several cell lines including LLC-PK1 （a porcine kidney tubular epithelial cell line）, MDCK （Madin-Darby canine kidney） and CTLL-2 （cytotoxic T-lymphocyte line） were treated with recombinant human TGF-131, and a series of experiments were carried out, involving Northern blot analysis of total RNA from these cells. Further, several specific chemical inhibitors were applied before TGF-β1 treatment to probe the signaling pathway. The results showed that TGF-β1 can significadtly up-regulate SHARP-2 mRNA expression in the LLC-PK1 cell line. The peak level of induction was found 2 h after TGF-β1 stimulation. While one phospho- inositide 3-kinases （PI-3） kinase inhibitor, LY294002, completely blocked the effect of TGF-131 on SHARP-2 mRNA expression in LLC-PK1 cells at a low concentration, other inhibitors, including PD98059, staurosporine, AG490, wortmannin, okadaic acid and rapamycin, had no effect. The effect of LY294002 was dose-dependent. We conclude that, in LLC-PK1 cells at least, TGF-β1 can effectively induce the SHARP-2 mRNA expression and that the PI-3 kinase pathway can mediate this effect.展开更多
基金supported by the General Program of the National Natural Science Foundation of China(51309220,31470776)QianJiang Talent Plan to W.Q.Lin
文摘Acute kidney injury （AKI） and chronic kidney disease （CKD） are worldwide public health problems affecting millions of people and have rapidly increased in prevalence in recent years. Due to the multiple causes of renal failure, many animal models have been developed to advance our understanding of human nephropathy. Among these experimental models, rodents have been extensively used to enable mechanistic understanding of kidney disease induction and progression, as well as to identify potential targets for therapy. In this review, we discuss AKI models induced by surgical operation and drugs or toxins, as well as a variety of CKD models （mainly genetically modified mouse models）. Results from recent and ongoing clinical trials and conceptual advances derived from animal models are also explored.
基金The authors are grateful for the financial supports from the National Key Research and Development Program of China(2016YFB0300801)the National Natural Science Foundation of China(11904093,51831004,51671082,51471067 and 11427806).
文摘The effect of Er on the microhardness and precipitation behavior of the heat-treated Al−Si−Mg alloy was investigated by microhardness tester and TEM.As a comparison,the influence of natural aging was also studied.It is shown that the thermal stability of the over-aged Al−Si−Mg−Er alloy is highly related to the average size of the precipitates.The average size ofβ''precipitates in Al−Si−Mg−Er alloy is smaller than that in Al−Si−Mg alloy,and the distribution is more localized under condition of without introducing natural aging.However,when natural aging is introduced before artificial aging,the Al−Si−Mg−Er alloy has similar average size and distribution of precipitates with the Al−Si−Mg alloy,resulting in similar mechanical properties.The effect of Er on the precipitation kinetics in the alloy was also discussed in detail to explain these phenomena.
基金the financial supports from the National Natural Science Foundation of China(Nos.51871096,52071136).
文摘The anomalous flow behavior of γ'-Ni_(3)Al phases at high temperature is closely related to the cross-slip of 1/2<110>{111}super-partial dislocations.Generalized stacking fault energy curves(i.e.,Γ-surfaces)along the lowest energy path can provide a great deal of information on the nucleation and movement of dislocations.With the first-principles calculation,the interplay between Re and W,Mo,Ta,Ti doped at preferential sites and their synergetic influence on Γ-surfaces and ideal shear strength(τ_(max))in γ'-Ni_(3)Al phases are investigated.Similar to single Re-addition,the Suzuki segregation of W at stacking faults is demonstrated to enable to impede the movement of 1/6<112>{111} Shockley partial dislocations and promote the cross-slip of 1/2<110>{111}super-partial dislocations.With the replacement of a part of Re by W,a decreased γ_(APB)^(111)/γ_(APB)^(001) indicates that the anomalous flow behavior of γ'phases at high temperature is not as excellent as the double Re-addition,but an increasedτmax means that the creep rupture strength of Ni-based single crystal superalloys can be benefited from this replacement to some extent,especially in the co-segregation of Re and W at Al−Al sites.As the interaction between X1_(Al) and X2_(Al) point defects is characterized by an correlation energy function ΔE^(X1_(Al)+X2_(Al))(d),it is found that both strong attraction and strong repulsion are unfavarable for the improvement of yield strengths of γ'phase.
基金Supported by the grant from the National Nature Science Foundation of China,No.81670621the Nature Science Foundation of Zhejiang Province,No.LY16H050001
文摘BACKGROUND Antiviral drugs are widely used in populations with viral infection caused by immunologic inadequacy.Because these drugs are mainly metabolized by the kidneys,patients with renal failure undergoing renal replacement therapy are prone to drug adverse effects and poisoning.Severe neurotoxicity caused by antiviral drugs is a rare but life-threatening complication.CASE SUMMARY This study reported one male patient on peritoneal dialysis who suffered from severe mental disorders after receiving an overdose of acyclovir and valacyclovir for the treatment of herpes zoster.The literature review suggested that hemodialysis is better than peritoneal dialysis to clear acyclovir from the circulation.The patient died after his consciousness deteriorated despite peritoneal dialysis and continuous blood purification.CONCLUSION This case emphasizes cautiousness when using anti-retroviral drugs in patients with uremia.Hemodialysis is optimal method to remove the drugs.
基金the National Key Research and Development Programme of China(2018YFC1314003)the Education of Zhejiang Province(Y201328620).
文摘1 Introduction Chronic kidney disease(CKD)often coexists with or is a complication of cardiovascular disease.Previous studies have shown that CKD increases the risk of cardiovascular death and all-cause death and was considered to be a risk equivalent of coronary heart disease.[1,2]Adjusted for confounders,decreased glomerular filtration rate(GFR)and increased albuminuria are both independent risk factors for cardiovascular events.[3,4]The risk for cardiovascular death linearly increases with the decline of GFR in a certain range(<70 mL/min per 1.73 m^2)and the increase of albuminuria without a threshold effect[3].
基金This work was supported by a grant from the National Natural Science Foundation of China （No. 81170707）.
文摘Background： High peritoneal transport status was previously thought to be a poor prognostic factor in peritoneal dialysis （PD） patients. However, its effect on diabetic nephropathy PD patients is unclear in consideration of the adverse impact of diabetes itself. The purpose of this study was to investigate the influence of peritoneal transport characteristics on nutritional status and clinical outcome in diabetic nephropathy patients on PD. Methods： One hundred and two diabetic nephropathy patients on PD were enrolled in this observational cohort study. According to the initial peritoneal equilibration test result, patients were divided into two groups： Higher transport group （HT, including high and high average transport） and lower transport group （LT, including low and low-average transport）. Demographic characteristics, biochemical data, dialysis adequacy, and nutritional status were evaluated. Clinical outcomes were compared. Risk factors for death-censored technique failure and mortality were analyzed. Results： Compared with LT group （n = 37）, serum albumin was significantly lower and the incidence of malnutrition by subjective global assessment was significantly higher in HT group （n = 65） （P 〈 0.05）. Kaplan-Meier analyses showed that death-censored technique failure and mortality were significantly increased in HT group compared with that in LT group. On multivariate Cox analyses, higher peritoneal transport status and lower residual renal function （RRF） were independent predictors of death-censored technique failure when adjusted for serum albumin and total weekly urea clearance （Kt/V）. Independent predictors of mortality were advanced age, anemia, hypoalbuminemia, and lower RRF, but not higher peritoneal transport status. Conclusions： Higher peritoneal transport status has an adverse influence on nutrition for diabetic nephropathy patients on PD. Higher peritoneal transport status is a significant independent risk factor for death-censored technique failure, but not for mortality in diabetic nephropathy patients on PD.
基金supported by the National Key Technology R&D Program of China(No.2011BAI10B07)the National Basic Research Program(973)of China(No.2012CB517603)the National High-Tech R&D Program(863)of China(No.2012AA02A512)
文摘Background and aims： Ingestion of paraquat （PQ）, a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul- monary fibrosis, for which there are no effective therapies. The aim of this study was to evaluate the effects of ra- pamycin （PAPA） on inhibiting PQ-induced pulmonary fibrosis in mice and to explore its possible mechanisms. Methods： Male C57BL/6J mice were exposed to either saline （control group） or PQ （10 mg/kg body weight, intraper- itoneally; test group）. The test group was divided into four subgroups： a PQ group （PQ-exposed, non-treated）, a PQ＋RAPA group （PQ-exposed, treated with RAPA at I mg/kg intragastrically）, a PQ＋MP group （PQ-exposed, treated with methylprednisolone （MP） at 30 mg/kg intraperitoneally）, and a PQ＋MP＋RAPA group （PQ-exposed, treated with MP at 30 mg/kg intraperitoneally and with PAPA at 1 mg/kg intragastrically）. The survival rate and body weight of all the mice were recorded every day. Three mice in each group were sacrificed at 14 d and the rest at 28 d after intox- ication. Lung tissues were excised and stained with hematoxylin-eosin （H＆E） and Masson＇s trichrome stain for his- topathological analysis. The hydroxyproline （HYP） content in lung tissues was detected using an enzyme-linked im- munosorbent assay （ELISA） kit. The expression of transforming growth factor-β1 （TGF-β1） and α-smooth muscle actin （α-SMA） in lung tissues was detected by immunohistochemical staining and Western blotting. Results： A mice model of PQ-induced pulmonary fibrosis was established. Histological examination of lung tissues showed that PAPA treatment moderated the pathological changes of pulmonary fibrosis, including alveolar collapse and interstitial collagen depo- sition. HYP content in lung tissues increased soon after PQ intoxication but had decreased significantly by the 28th day after PAPA treatment. Immunohistochemical staining and Western blotting showed that PAPA treatment significantly down-regulated the enhanced levels of TGF-β1 and e-SMA in lung tissues caused by PQ exposure. However, PAPA treatment alone could not significantly ameliorate the lower survival rate and weight loss of treated mice. MP treatment enhanced the survival rate, but had no significant effects on attenuating PQ-induced pulmonary fibrosis or reducing the expression of TGF-β1 and a-SMA. Conclusions： This study demonstrates that PAPA treatment effectively suppresses PQ-induced alveolar collapse and collagen deposition in lung tissues through reducing the expression of TGF-β1 and a-SMA. Thus, RAPA has potential value in the treatment of PQ-induced pulmonary fibrosis.
基金supported by the National Key Technology R&D Program of China(No.2013BAI09B04)the Medical Research Funds from the Bureau of Health of Zhejiang Province(No.2013KYA072),China
文摘Objective： The treatment of Henoch-Schonlein purpura （HSP） with moderate proteinuria remains con- troversial. We retrospectively analyzed the efficacy of immune suppressants, with a particular emphasis on myco- phenolate mofetil （MMF）. Methods： Ninety-five HSP patients with moderate proteinuria （1.0-3.5 g/24 h） after at least three months of therapy with angiotensin-converting enzyme inhibitor （ACEI） or angiotensin receptor blocker （ARB） were divided into three groups： an MMF group （n=33） that received MMF 1.0-1.5 g/d combined with prednisone （0.4-0.5 mg/（kg.d））, a corticosteroid （CS） group （n=31） that received full-dose prednisone （0.8-1.0 mg/（kg.d））, and a control group （n=31）. Patients in the MMF and CS groups continued to take ACEI or ARB at the original dose. The patients in the control group continued to take ACEI or ARB but the dose was increased by （1.73±0.58）-fold. The patients were followed up for 6-78 months （median 28 months）. Results： The baseline proteinuria was higher in the MMF group （（2.1±0.9） g/24 h） than in the control group （（1.6±0.8） g/24 h） （P=0.039）. The proteinuria decreased sig- nificantly in all groups during follow-up, but only in the MMF group did it decrease significantly after the first month. At the end of follow-up, the proteinuria was （0.4±0.7） g/24 h in the MMF group and （0.4±0.4） g/24 h in the CS group, significantly lower than that in the control group （（0.9±1.1） g/24 h）. The remission rates in the MMF group, CS group, and control group were respectively 72.7%, 71.0%, and 48.4% at six months and 72.7%, 64.5%, and 45.2% at the end of follow-up. The overall number of reported adverse events was 17 in the MMF group, 30 in the CS group, and 6 in the control group （P〈0.001）. Conclusions： MMF with low-dose prednisone may be as effective as full-dose prednisone and tend to have fewer adverse events. Therefore, it is probably superior to conservative treatments of adult HSP patients with moderate proteinuria.
基金Project supported by the National Science and Technology Major Project of China(Nos.2012ZX09505001-002 and 2015ZX09501004-002-002)the Zhejiang Provincial Science and Technology Planning Project of China(No.2014C03009)
文摘Radix Sophorae tonkinensis(RST) is a widely used herb in Traditional Chinese Medicine(TCM) for treating infectious and inflammatory diseases. However, the toxicity data for RST are limited. The aim of this work is to assess and compare the toxicity of the whole RST extract and its five active fractions using the zebrafish model. Five active fractions of RST were prepared using five different types of solvents, which included dealkalized water, ethanol, n-butyl ethanol, dichloromethane, and diethyl ether. The chemical profiles of the active fractions were determined by high-performance liquid chromatography(HPLC), and the toxicity observed in the zebrafish model was confirmed using mouse models. In the zebrafish model, cardiovascular toxicity was observed for the fraction extracted using diethyl ether, and hepatotoxicity was observed for the whole RST extract and the fractions extracted using water and ethanol, whereas both cardiovascular and hepatic toxicities were observed for the fractions extracted using n-butyl ethanol and dichloromethane. The hepatotoxicity of the fractions extracted using n-butyl ethanol and dichloromethane was also observed in mice. Our findings provide the toxicity data for RST and its five active fractions through modeling in a zebrafish, and indicate that the different fractions may each have a different toxicity, which is helpful for the optimal use of RST in clinical practice.
基金financially supported by the National Natural Science Foundation of China(Nos.51371081, 11427806,51471067,51501059 and 51171063)the National Basic Research Program of China(No.2009CB623704)
文摘The A1-Cu-Li-（Mg） alloy is a high-performance lightweight material strengthened by complex coexisting precipitates that form in the alloy upon thermal ageing. Using high-resolution （scanning） transmission electron microscopy in association with first-principles energy calculations, we systematically studied the complex coexisting precipitates in the alloys and correlated their precipitation sequences with thermal ageing processes applied. The principal results are the following： （1） eight types of precipitates can be observed in the alloy; （2） of these precipitates, the Tl-phase is most stable. The S-phase precipitates with segregated Li atoms at their interfacial edges are unexpectedly more stable than the a-phase; （3） the Tl-phase has a characteristic precursor that plays the key role in its nucleation and growth.
基金financially supported by the National Natural Science Foundation of China(Nos.51831004,11427806,51671082,51471067,11904093)the National Key Research and Development Program of China(No.2016YFB0300801)。
文摘Pre-deformation before aging has been demonstrated to have a positive effect on the mechanical strength of the 7N01 alloy in our previous study,which is rather different from the general negative effects of pre-deformation on high-strength 7XXX aluminum alloys.In order to explain the strengthening mechanism relating to the positive effect,in the present study,the microstructure of the aged 7N01 alloy with different degrees of pre-deformation was investigated in detail using advanced electron microscopy techniques.Our results show that,without pre-deformation,the aged alloy is strengthened mainly by the η′type of hardening precipitates.In contrast,with pre-deformation,the aged alloy is strengthened by the hierarchical microstructure consisting of the GP-η′type of precipitates formed inside sub-grains,the ηp type of precipitates formed at small-angle boundaries,and the dislocation introduced by pre-deformation(residual work-hardening effect).By visualizing the distribution of theηp precipitates through three-dimensional electron tomography,the 3 D microstructures of dislocation cells are clearly revealed.Proper combinations of ηp precipitates,GP-η′precipitates and residual dislocations in the alloy are responsible for the positive effect of pre-deformation on its mechanical properties.
文摘The purpose of this review is to objectively evaluate the biochemical and pathophysiological properties of 0.9% saline （henceforth： saline） and to discuss the impact of saline infusion, specifically on systemic acid-base bal- ance and renal hemodynamics. Studies have shown that electrolyte balance, including effects of saline infusion on serum electrolytes, is often poorly understood among practicing physicians and inappropriate saline prescribing can cause increased morbidity and mortality. Large-volume （〉2 L） saline infusion in healthy adults induces hyperohloremia which is associated with metabolic acidosis, hyperkalemia, and negative protein balance. Saline overload （80 ml/kg） in rodents can cause intestinal edema and contractile dysfunction associated with activation of sodium-proton exchanger （NHE） and decrease in myosin light chain phosphorylation. Saline infusion can also adversely affect renal hemody- namics. Microperfusion experiments and real-time imaging studies have demonstrated a reduction in renal perfusion and an expansion in kidney volume, compromising 02 delivery to the renal perenchyma following saline infusion. Clinically, saline infusion for patients post abdominal and cardiovascular surgery is associated with a greater number of adverse effects including more frequent blood product transfusion and bicarbonate therapy, reduced gastric blood flow, delayed recovery of gut function, impaired cardiac contractility in response to inotropes, prolonged hospital stay, and possibly increased mortality. In critically ill patients, saline infusion, compared to balanced fluid infusions, in- creases the occurrence of acute kidney injury. In summary, saline is a highly acidic fluid. With the exception of saline infusion for patients with hypochloremic metabolic alkalosis and volume depletion due to vomiting or upper gastroin- testinal suction, indiscriminate use, especially for acutely ill patients, may cause unnecessary complications and should be avoided. More education regarding saline-related effects and adequate electrolyte management is needed.
基金supported by the National Key Research and Development Program of China(No. 2016YFB0300801)the National Natural Science Foundation of China(Nos.11427806,51471067,51371081,51671082 and 51601060)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20120161110036)the Hunan Provincial Natural Science Foundation of China(No.14JJ4052)
文摘Intrinsic stacking-fault energy is a critical parameter influencing the various mechanical performances of aus- tenitic steels with high Mn concentrations. However, quantitative calculations of the stacking-fault energy （SFE） of the face-centered cubic （fcc） Fe, including the changes in concentrations and geometrical distribution of alloying atoms, cannot be obtained by using previous computation models. On the basis of the interaction energy model, we evaluated the effects of a single alloying atom （i.e., Mn, A1, Si, C and N）, as well as its aggregates, including the Mn-X dimer and Mn2-X trimer （X = A1, Si, C and N） on the SFE of the fcc Fe via first-principle calculations. Given low concentrations （〈10 wt%） of alloying atoms, dimers and trimers, theoretical calculations reveal the following： （1） Alloying atom Mn causes a decrease in the SFE, whereas A1, Si, C and N significantly increase the SFE; （2） combination with other alloying atoms to form the Mn-X dimer （X = A1, Si, C and N） exerts an effect on SFE that, to a certain extent, is close to that of the corresponding single X atom; （3） the interaction between Mnz-X and the stacking fault is stronger than that of the corresponding single X atom, inducing a significant increase in the SFE of fcc Fe. The theoretical results we obtained demonstrate that the increase in SFE in high-Mn steel originates from the synergistic effect of Mn and other trace alloy atoms.
基金supported by the National Key Research and Development Program of China(No.2016YFB0300801)the National Natural Science Foundation of China(Nos.51471067,11427806 and 51671082)
文摘Enhancing combinatorial properties,such as excellent corrosion resistance,high strength and good ductility combined,is an important issue for manufacturing high-quality AlMgSi(Cu)alloys.Here,we show that this can be achieved by optimizing a combinatorial process consisting of pre-ageing,cold-rolling and post-ageing to tailor the hierarchical microstructures of the alloy.Transmission electron microscopy analysis reveals that the enhanced combinatorial properties of corrosion resistance,strength and ductility are owing to modification of grain boundary microstructure in good association with changes of precipitate microstructures and a more homogenous distribution of solute atoms,as compared with the microstructures of the alloy processed by thermal ageing only.
基金supported by the National Key Technology R&D Program of China(No.2011BAI10B07)the National Basic Research Program(973)of China(No.2012CB517603)the National High-Tech R&D Program(863)of China(No.2012AA02A512)
文摘Objective： To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs （NSAIDs） in renal ischemia-reperfusion injury （IRI） and the cyclooxygenase （COX）-1/2 blockade association by indomethacin （IMT） in the mice model. Methods： After the left renal pedicle of mice was clamped, IMT was administrated by intraperitoneal injection with four doses： 1, 3, 5, and 7 mg/kg. Blood and kidney samples were collected 24 h after IRI. The renal functions were assayed by the cytokines and serum creatinine （SCr） using enzyme-linked immunosorbent assay （ELISA） kits. Kidney samples were analyzed by hematoxylin and eosin （H＆E） and immunohistochemistry stainings. Results： The mice administered with 5 mg/kg IMT had a marked reduction in SCr and significantly less tubular damage The tumor necrosis factor a （TNF-α） activity in renal homogenates and interleukin 6 （IL-6） activity in serum had a marked reduction at doses of 5 and 7 mg/kg IMT. The administration of 3 and 5 mg/kg IMT had a marked reduction in the ratio of thromboxane B2 to 6-keto-prostaglandin F1α. COX-1 and COX-2 stainings were weaker in 5 mg/kg IMT groups than that in the other groups. Conclusions： There was a dose response in the IMT function of renal IRI in mice, and IMT had a protective effect in a certain dose range. The effect of IMT on mice IRI was related to COX-1/2 blockades.
基金financial support from the National Natural Science Foundation of China(No.51971249)the Natural Science Foundation of Shandong Province(No.ZR2020KE012)。
文摘The formation of highly coherent double-shelled L1_(2) nano-precipitates in dilute Al–Er–Sc–Zr alloys was investigated with the combined use of Cs-corrected transmission electron microscopy characterization and first-principles energetics calculations. The double-shelled nano-precipitates are primarily featured with an Er-rich core surrounded by a Sc-rich inner shell and a Zr-rich outer shell. First-principles energetics analyses based on the classic homogenous nucleation theory suggested that once forms, this double-shell structure can be thermally stable. The predominant formation of this double-shell structure has thus both profound kinetic and thermodynamic origins. Its formation and stability preference to all other possible L1_(2) nano-structures would become more pronounced as its size increases, no matter what the solute ratio and aging temperature of interest.
基金supported by the National Natural Science Foundation of China (Nos. 11427806, 51471067, 51671082, 51671086 and 51302313)the National Key Research and Development Program of China (No. 2016YFB0300801)
文摘Owing to the excellent elastic properties and chemical stability,binary metal or light element borides,carbides and nitrides have been extensively applied as hard and low-compressible materials.Researchers are searching for harder materials all the time.Recently,the successful fabrication of nano-twinned cubic BN(Tian et al.Nature 493:385–388,2013)and diamond(Huang et al.Nature 510:250–253,2014)exhibiting superior properties than their twin-free counterparts allows an efficient way to be harder.From this point of view,the borides,carbides and nitrides may be stronger by introducing twins,whose formation tendency can be measured using stacking fault energies(SFEs).The lower the SFEs,the easier the formation of twins.In the present study,by means of first-principles calculations,we first calculated the fundamental elastic constants of forty-two borides,seventeen carbides and thirty-one nitrides,and their moduli,elastic anisotropy factors and bonding characters were accordingly derived.Then,the SFEs of the{111}<112>glide system of twenty-seven compounds with the space group F43 m or Fm3m were calculated.Based on the obtained elastic properties and SFEs,we find that(1)light element compounds usually exhibit superior elastic properties over the metal borides,carbides or nitrides;(2)the 5 d transitionmetal compounds(ReB2,WB,OsC,RuC,WC,OsN2,TaN and WN)possess comparable bulk modulus(B)with that of cBN(B=363 GPa);(3)twins may form in ZrB,HfN,PtN,VN and ZrN,since their SFEs are lower or slightly higher than that of diamond(SFE=277 mJ/m^2).Our work can be used as a valuable database to compare these compounds.
基金supported by the National Natural Science Foundation of China(Nos.51831004,52171006 and 11427806)。
文摘Mechanical theories show that properties of alloys are strongly dependent on the morphological parameters oftheir strengthening precipitates.However,accurate measurement of precipitates microstructure parameters is still a challenging task.In this article,we develop a quantitative electron tomography method by combining computer vision technology to accurately characterize the three-dimensional microstructure parameters,such as volume fractions,sizes and distributions,of the T_(1) and δ’/θ’/δ’ precipitates in Al-Cu-Li(-Mg) alloys.Since they have extremely large aspect-ratios in shape and large numbers in density upon formation in the Al matrix,these thin plate-like precipitates are difficult to be characterized quantitatively without the assistance of computer vision technology.It is shown that the property difference between two peak-aged states of the alloy can be well explained with the quantitative precipitate parameters correctly measured.Using these correct precipitate data,we also tested the validity of current mechanical models for projecting the contribution of precipitates to the strengths of the alloy,demonstrating that quantitative relations between strength and micro structure parameters still need to be refined.
基金supported by the National Natural Science Foundation of China (Nos. 11427806, 51471067, 51371081, 51171063, 51501059 and 51501060)the National Basic Research (973) Program of China (No. 2009CB623704)+2 种基金the Chinese Postdoctoral Science Foundation (No. 2015M582324)the Hunan Provincial Natural Science Foundation (No. 14JJ4052)the Science and Technology Project for Good Postdoctoral Education of China (No. 2015RS4020)
文摘Three types of symmetric （1120） tilt low-angle grain boundaries （LAGBs） with array of basal, prismatic, and pyramidal edge full 〈a〉 dislocations in pure Mg have been studied by using the improved Peierls-Nabarro model in combination with the generalized stacking fault energy curve. The results show that with decreasing distance between the dislocations in all the three types of tilt LAGBs, the stress and strain fields are gradually suppressed. The reduction extent of the stress and strain fields decreases from the prismatic to basal to pyramidal dislocations. The variation of dislocation line energy （DLE） for all tilt LAGBs is divided into three stages： DLE changes slightly and linearly when the distance is larger than 300 A, - 10%; DLE declines exponentially and quickly when the distance goes from 300 to 100 A, ,- 70%; and finally, the descent speed lowers when the distance is smaller than 100 A and the dislocation core energy is nearly half of the DLE. The grain boundary energy （GBE） decreases when the tilt angle of LAGB increases from1 ° to 2° for all cases. The tilt LAGB consists of pyramidal dislocations always has the largest GBE, while that with array of prismatic dislo- cations has the smallest one in the whole range. The Peierls stress of dislocation in tilt LAGB is nearly unchanged, the same as that of single dislocation. This work is useful for further study of dissociated dislocation, solute segregation, precipitate nucleation in tilt LAGB and its interaction with single dislocations.
基金supported by the National Natural Science Foundation of China (Nos. 30471641 and 30872389)the Natural Science Foundation of Zhejiang Province, China (No. Y207088)
文摘We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this study, several cell lines including LLC-PK1 （a porcine kidney tubular epithelial cell line）, MDCK （Madin-Darby canine kidney） and CTLL-2 （cytotoxic T-lymphocyte line） were treated with recombinant human TGF-131, and a series of experiments were carried out, involving Northern blot analysis of total RNA from these cells. Further, several specific chemical inhibitors were applied before TGF-β1 treatment to probe the signaling pathway. The results showed that TGF-β1 can significadtly up-regulate SHARP-2 mRNA expression in the LLC-PK1 cell line. The peak level of induction was found 2 h after TGF-β1 stimulation. While one phospho- inositide 3-kinases （PI-3） kinase inhibitor, LY294002, completely blocked the effect of TGF-131 on SHARP-2 mRNA expression in LLC-PK1 cells at a low concentration, other inhibitors, including PD98059, staurosporine, AG490, wortmannin, okadaic acid and rapamycin, had no effect. The effect of LY294002 was dose-dependent. We conclude that, in LLC-PK1 cells at least, TGF-β1 can effectively induce the SHARP-2 mRNA expression and that the PI-3 kinase pathway can mediate this effect.
