Microstructure and mechanical properties of new Mg-Zn-Y-Zr alloys with high castability and ignition resistance

Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out.The content range for the formation of the two-phase structure MgSS(Mg solid solution)+LPSO(long-period stacking ordered)in alloys of the Mg-Zn-Y-Zr system was determined by thermodynamic calculations.The effect of heat treatment regimes on microstructure,mechanical,and corrosion properties was invest-igated.The fluidity,hot tearing tendency,and ignition temperature of the alloys were determined.The best combination of castability,mechanical,and corrosion properties was found for the Mg-2.4Zn-4Y-0.8Zr alloy.The alloys studied are superior to their industrial counterparts in terms of technological properties,while maintain high corrosion and mechanical properties.The increased level of pro-perties is achieved by a suitable heat treatment regime that provides a complete transformation of the 18R to 14H modification of the LPSO phase.

Effects of temperature on critical resolved shear stresses of slip and twining in Mg single crystal via experimental and crystal plasticity modeling

Magnesium(Mg)single crystal specimens with three different orientations were prepared and tested from room temperature to 733 K in order to systematically evaluate effects of temperature on the critical resolved shear stress(CRSS)of slips and twinning in Mg single crystals.The duplex non-basal slip took place in the temperature range from 613 to 733 K when the single crystal samples were stretched along the<0110>direction.In contrast,the single basal slip and prismatic slip were mainly activated in the temperature range from RT to 733 K when the tensile directions were inclined at an angle of 45°with the basal and the prismatic plane,respectively.Viscoplastic self-consistent(VPSC)crystal modeling simulations with genetic algorithm code(GA-code)were carried out to obtain the best fitted CRSSs of major deformation modes,such as basal slip,prismatic slip,pyramidalⅡ,{1012}tensile twinning and{1011}compressive twinning when duplex slips accommodated deformation.Additionally,CRSSs of the basal and the prismatic slip were derived using the Schmid factor(SF)criterion when the single slip mainly accommodated deformation.From the CRSSs of major deformation modes obtained by the VPSC simulations and the SF calculations,the CRSSs for basal slip and{1012}tensile twinning were found to show a weak temperature dependence,whereas those for prismatic,slip and{1011}compressive twinning exhibited a strong temperature dependence.From the comparison of previous results,VPSC-GA modeling was proved to be an effective method to obtain the CRSSs of various deformation modes of Mg and its alloys.

New insights into the pathogenesis of primary biliary cholangitis asymptomatic stage

Primary biliary cholangitis(PBC)is a chronic cholestatic progressive liver disease and one of the most important progressive cholangiopathies in adults.Damage to cholangiocytes triggers the development of intrahepatic cholestasis,which progresses to cirrhosis in the terminal stage of the disease.Accumulating data indicate that damage to biliary epithelial cells[(BECs),cholangiocytes]is most likely associated with the intracellular accumulation of bile acids,which have potent detergent properties and damaging effects on cell membranes.The mechanisms underlying uncontrolled bile acid intake into BECs in PBC are associated with pH change in the bile duct lumen,which is controlled by the bicarbonate(HCO3-)buffer system“biliary HCO3-umbrella”.The impaired production and entry of HCO3-from BECs into the bile duct lumen is due to epigenetic changes in expression of the X-linked microRNA 506.Based on the growing body of knowledge on the molecular mechanisms of cholangiocyte damage in patients with PBC,we propose a hypothesis explaining the pathogenesis of the first morphologic(ductulopenia),immunologic(antimitochondrial autoantibodies)and clinical(weakness,malaise,rapid fatigue)signs of the disease in the asymptomatic stage.This review focuses on the consideration of these mechanisms.

Influence of Zr and Mn additions on microstructure and properties of Mg-2.5wt%Cu-Xwt%Zn(X=2.5,5 and 6.5)alloys

This work studied the effects of adding Zr and Mn in amounts less than 1wt%on the microstructure,mechanical properties,casting properties,and corrosion resistance of Mg-Zn-Cu alloys containing 2.5wt%Cu and 2.5wt%-6.5wt%Zn.The hardness and electrical conductivity measurements were used to find an optimal heat treatment schedule with the best mechanical properties.It has been established that Zr significantly increases the yield strength of the alloys due to a strong grain refinement effect.However,the presence of Mn and Zr has a detrimental effect on alloy’s elongation at fracture.It was shown that the precipitation of the Mg_(2)Cu cathodic phase in the alloy structure negatively affects the corrosion behavior.Nevertheless,the addition of Mn decreases the corrosion rate of the investigated alloys.The best combination of the mechanical,casting,and corrosion properties were achieved in the alloys containing 2.5wt%Cu and 5wt%Zn.However,the Mn or Zr addition can improve the properties of the alloys;for example,the addition of Mn or Zr increases the fluidity of the alloys.

“Eli-P-Complex” Diagnostic Test for Preconception Care in Women with History of Adverse Pregnancy Outcome: A Randomized Multicenter Trial

Background: ELI-P-Complex is the most advanced diagnostic test designed to assess whether the female body is ready (or unready) for the normal pregnancy course and for giving birth to a healthy child. ELI-P-Complex enables the perceived abnormalities to be individually treated even prior to the pregnancy planning, thus minimizing the risk of gestational and delivery-related complications. This prospective study shows the effectiveness of ELI-P-Complex testing during preconception care in women with a history of adverse pregnancy outcomes (APO). Methods: The data were reviewed from 4519 women with a history of APO and who planned to get pregnant. Following randomization, subjects of Group A were tested with ELI-P-Complex and treated before the pregnancy based on the results obtained. Group B subjects were not examined using the ELI- P-Complex test and were prepared for pregnancy in accordance with the standard strategy of pre- conception care [1]. Results: In Group A, gestational complications (GC) were revealed in 20% of women compared to 88.7% of Group B subjects;the relative risk (RR) of GC was 11.67 (95% CI: 9.9851 to 13.6392;P < 0.0001). APO was reported in 12% of Group A subjects vs. 38.1% of Group B ones;RR of APO was 5.8908 (95% CI: 4.9365 to 7.0296;P < 0.0001). Absolutely healthy children were born from 88.1% of Group A subjects compared to 50.3% of Group B ones;RR was 7.9601 (95% CI: 6.6110 to 9.5845;P < 0.0001). The positive predictive value, sensitivity, and specificity of the test for GC were 93.82% (95% CI: 92.72% to 94.80%), 93.17% (95% CI: 92.03% to 94.20%), and 92.62% (95% CI: 91.31% to 93.78%), respectively. Conclusions: The use of ELI-P-Complex for examination and further preconception care in women with a history of APO considerably reduces GC, improves pregnancy outcomes, and increases chances of giving birth to a healthy child.

Immunopathogenesis of chronic hepatitis B

Chronic hepatitis B (CHB) is a widespread infectious disease with unfavorable outcomes and life-threatening consequences for patients, in spite of modern vaccination and antiviral treatment modalities. Cutting-edge experimental approaches have demonstrated key pathways that involve cross-talk between viral particles and host immune cells. All events, including penetration of hepatitis B virus (HBV) particles into host cells, establishing persistence, and chronization of CHB infection, and possibility of complete elimination of HBV particles are controlled by the immune system. Researchers have paid special attention to the replication capacity of HBV in host cells, which is associated with cellular changes that reflect presentation of viral antigens and variability of HBV antigen features. In addition, specific HBV proteins have an immune-modulating ability to initiate molecular mechanisms that &#x0201c;avoid&#x0201d; control by the immune system. The relationship between immunological shifts and chronic infection stages has been intensively studied since it was recognized that the immune system is a direct participant in the recurrent (cyclic) nature of CHB. Understanding the wide diversity of molecular pathways and the crosstalk between innate and adaptive immune system components will provide fresh insight into CHB immune pathogenesis and the possibilities of developing new treatment strategies for this disease.

Torque teno virus in liver diseases: On the way towards unity of view

The review presents the data accumulated for more than 20 years of research of torque teno virus(TTV).Its molecular genetic structure,immunobiology,epidemiology,diagnostic methods,possible replication sites,and pathogenicity factors are described.TTV is a virus that is frequently detectable in patients with different viral hepatitides,in cases of hepatitis without an obvious viral agent,as well as in a healthy population.There is evidence suggesting that biochemical and histological changes occur in liver tissue and bile duct epithelium in TTV monoinfection.There are sufficient histological signs of liver damage,which confirm that the virus can undergo a replicative cycle in hepatocytes.Along with this,cytological hybridization in TTV-infected cells has shown no substantial cytopathic(cell-damaging)effects that are characteristic of pathogenic hepatotropic viruses.Studying TTV has led to the evolution of views on its role in the development of human pathology.The first ideas about the hepatotropism of the virus were gradually reformed as new data became available on the prevalence of the virus and its co-infection with other viruses,including the viruses of the known types of hepatitides.The high prevalence of TTV in the human population indicates its persistence in the body as a virome and a nonpathogenic virus.It has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body’s immune status.The available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis viruses.Fortunately,the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic properties.The ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.

Molecular pathways of liver regeneration:A comprehensive review

The liver is a unique parenchymal organ with a regenerative capacity allowing it to restore up to 70%of its volume.Although knowledge of this phenomenon dates back to Greek mythology(the story of Prometheus),many aspects of liver regeneration are still not understood.A variety of different factors,including inflammatory cytokines,growth factors,and bile acids,promote liver regeneration and control the final size of the organ during typical regeneration,which is performed by mature hepatocytes,and during alternative regeneration,which is performed by recently identified resident stem cells called“hepatic progenitor cells”.Hepatic progenitor cells drive liver regeneration when hepatocytes are unable to restore the liver mass,such as in cases of chronic injury or excessive acute injury.In liver maintenance,the body mass ratio is essential for homeostasis because the liver has numerous functions;therefore,a greater understanding of this process will lead to better control of liver injuries,improved transplantation of small grafts and the discovery of new methods for the treatment of liver diseases.The current review sheds light on the key molecular pathways and cells involved in typical and progenitor-dependent liver mass regeneration after various acute or chronic injuries.Subsequent studies and a better understanding of liver regeneration will lead to the development of new therapeutic methods for liver diseases.

Maintaining the metabolic homeostasis of Helicobacter pylori through chronic hyperglycemia in diabetes mellitus:A hypothesis

Helicobacter pylori(H.pylori)infection occurs in almost half of the world's population,most of whom are merely carriers of this microorganism.H.pylori is shown to be detected more frequently in patients with diabetes mellitus(DM)than in the general population,which is accompanied by a significantly increased risk of developing H.pylori-associated diseases.In addition,eradication therapy shows a low efficiency for H.pylori infection in patients with DM.There is a relationship between the level of chronic hyperglycemia and a higher detection rate of H.pylori as well as a lower efficiency of eradication therapy in patients with DM.The exact mechanisms of these phenomena are unknown.The authors make a hypothesis that explains the relationship between chronic hyperglycemia and the increased detection rate of H.pylori,as well as the mechanisms contributing to the improved survival of this bacterium in patients with DM during eradication therapy.

Efficacy of the new therapeutic approach in curing malignant neoplasms on the model of human glioblastoma

Objective:Glioma is a highly invasive tumor,frequently disposed in essential areas of the brain,which makes its surgical excision extremely difficult;meanwhile adjuvant therapy remains quite ineffective.Methods:In the current report,a new therapeutic approach in curing malignant neoplasms has been performed on the U87 human glioblastoma model.This approach,termed"Karanahan",is aimed at the eradication of cancer stem cells(CSCs),which were recently shown to be capable of internalizing fragments of extracellular double-stranded DNA.After being internalized,these fragments interfere in the process of repairing interstrand cross-links caused by exposure to appropriate cytostatics,and such an interference results either in elimination of CSCs or in the loss of their tumorigenic potency.Implementation of the approach requires a scheduled administration of cytostatic and complex composite double-stranded DNA preparation.Results:U87 cells treated in vitro in accordance with the Karanahan approach completely lost their tumorigenicity and produced no grafts upon intracerebral transplantation into immunodeficient mice.In SCID mice with developed subcutaneous grafts,the treatment resulted in reliable slowing down of tumor growth rate(P<0.05).In the experiment with intracerebral transplantation of U87 cells followed by surgical excision of the developed graft and subsequent therapeutic treatment,the Karanahan approach was shown to reliably slow down the tumor growth rate and increase the median survival of the mice twofold relative to the control.Conclusions:The effectiveness of the Karanahan approach has been demonstrated both in vitro and in vivo in treating developed subcutaneous grafts as well as orthotopic grafts after surgical excision of the tumor.

Mechanism for development of malnutrition in primary biliary cholangitis

Primary biliary cholangitis(PBC)is a chronic cholestatic liver disease that is associated with impaired biliary excretion processes.Along with the development of cholestasis,there is a deficient flow of bile acids into the intestinal lumen causing malnutrition(MN)that is manifested in deficiencies of both macro-and micronutrients.The mechanism for development of trophological insufficiency is multifactorial.However,the trigger of MN in PBC is impaired enterohepatic circulation of bile acids.The ingress of bile acids with a detergent effect into the general bloodstream,followed by elimination via the kidneys and skin,triggers a cascade of metabolic disturbances,which leads to the gradual development and progression of calorie MN.The latter gradually transforms into protein-calorie MN(PСM)(as marasmus)due to the insufficient entry of bile acids into the duodenum,which is accompanied by a decrease in the emulsification,hydrolysis,and absorption of fats and fat-soluble vitamins,as well as disturbance of intestinal motility and bacterial overgrowth.Fat-soluble vitamin deficiencies complement PСM with vitamin and mineral MN.The development of hepatocellular failure enhances the progression of PСM due to the impaired protein synthetic function of hepatocytes in the advanced stage of PBC,which results in deficiency of not only the somatic but also the visceral pool of proteins.A mixed PСM form of marasmus and kwashiorkor develops.Early recognition of energy,protein,micronutrient,and macronutrient deficiencies is of great importance because timely nutritional support can improve liver function and quality of life in patients with PBC.In this case,it is important to know what type(energy,proteincalorie,vitamin,and vitamin-mineral)and form(marasmus,marasmuskwashiorkor)of MN is present in the patient and how it is associated with the stage of the disease.Therefore,it is recommended to screen all patients with PBC for MN,from the early asymptomatic stage of the disease in order to identify and avoid preventable complications,such as fatigue,malaise,performance decrement,sarcopenia,osteoporosis,and hepatic encephalopathy,which will be able to provide appropriate nutritional support for correction of the trophological status.

Recent research progress on magnesium alloys in Korea:A review

This review highlights the recent advancements in Mg research in South Korea with a prime focus on high-speed-extrudable Mg–Bi-based alloys for high productivity and strength,innovative techniques utilizing{10–12}twinning for improved mechanical properties,and alloying and processing methods for enhanced corrosion resistance.High-alloyed Mg–Bi-based alloys possess thermally stableα-Mg matrix and secondary phase,which ensures high-speed extrusion of these alloys at elevated temperatures without hot cracking.Consequently,they exhibit outstanding extrudability with a maximum extrusion speed of up to 70 m/min.Furthermore,their high alloying contents offer excellent strength even after high-speed extrusion through strong solid solution hardening and particle hardening effects,making them suitable for high-performance extruded Mg products.The pre-twinning process utilizing{10–12}twinning and the combined process of pre-twinning and subsequent annealing have shown promise in controlling microstructure and texture of wrought Mg alloys and thus enhancing their mechanical properties.The pre-twinning process enhances tensile strength,fatigue properties,and age-hardening rate of Mg alloys.Furthermore,the combined processes of pre-twinning and subsequent annealing considerably improve their ductility,stretch formability,bending formability,and damping capacity.Efforts have been made to improve the corrosion resistance of Mg alloys through alloying additions,process treatments,and surface coatings.Alloying elements like Ca,Sc,and Sm alter the microstructural features(such as secondary phases and grain size)that affect the corrosion phenomenon.Process treatments such as multidirectional forging,screw rolling,and pulse electron beam can also improve the corrosion resistance by refining the microstructure.Furthermore,advanced surface coating technologies can create durable and corrosion-resistant layers for effectively protecting the Mg alloys.All these research activities conducted in South Korea have considerably contributed to the widespread utilization of Mg alloys in diverse applications by overcoming the inherent limitations of Mg alloys such as low extrudability,formability,and corrosion resistance.

Helicobacter pylori:Commensal,symbiont or pathogen?

This review considers the data on Helicobacter pylori(H.pylori),which have been accumulated over 40 years since its description as an etiological factor in gastrointestinal diseases.The majority of modern publications are devoted to the study of the pathogenic properties of the microorganism in the development of chronic gastritis,peptic ulcer disease,and gastric cancer,as well as methods for its eradication.However,in recent years,there have been more and more studies which have suggested that H.pylori has a beneficial,or potentially positive,effect on the human body.The authors have attempted to objectively analyze the information accumulated in the literature on H.pylori.Some studies consider it as one of the recently identified human bacterial pathogens,and special attention is paid to the evidence suggesting that it is probably part of the composition of the human microbiome as a commensal(commensal from French to English is a table companion)or even a symbiont.The presented data discussing the presence or absence of the effect of H.pylori on human health suggest that there is an apparent ambiguity of the problem.The re-assessment of the data available on H.pylori infection is important in order to answer the question of whether it is necessary to create a program of mass H.pylori eradication or to apply a more personalized approach to treating patients with H.pylori-associated gastrointestinal diseases and to perform eradication therapy.

2018世界肾脏日：关注女性和肾脏疾病

女性是现代家庭和社会的重要贡献者。但目前在世界范围内,男性和女性在受教育程度、医疗保健等方面仍存在显著差异。2018年第13个世界肾脏日恰逢国际妇女节,其主题是"肾脏和女性健康",给我们提供了一个关注女性健康,尤其是女性肾脏健康的重要契机。为此,世界肾脏日指导委员会(World Kidney Day Steering Committee)特别组织了全球具有代表性的5位女性肾脏病学家,撰写了述评文章,借机呼吁肾脏病学术领域和全社会更加重视女性健康,让更多女性从肾脏病学术研究中获益。关注女性肾脏健康,利在当代功在千秋!