Nb/NiTi复合材料预变形过程中变形行为的原位同步辐射X射线衍射研究

通过原位同步辐射X射线衍射、透射电子显微术和拉伸测试等表征手段,系统研究Nb/NiTi复合材料在预变形过程中的变形机制。结果表明:在加载过程中,Nb/NiTi复合材料经历B19′、B2和β-Nb相的弹性伸长和轻微的塑性变形,以及从B2相到B19′相的应力诱发马氏体相变。在随后的卸载过程中,Nb/NiTi复合材料的变形机制主要包括B19′、B2和β-Nb相的弹性恢复,β-Nb相的压缩变形以及不完全B19′→B2逆马氏体相变。在拉伸加载-卸载过程中,除了固有的弹性变形和应力诱发马氏体相变以外,复合材料中B19′马氏体内部的(001)复合孪晶也有助于材料实现弹性变形。因此,由于弹性变形、部分可逆且“连续”的应力诱发马氏体相变以及(001)复合孪晶的共同作用,Nb/NiTi复合材料在卸载完成后能够呈现出大的可恢复应变量。

MicroRNA expression in the hippocampal CA1 region under deep hypothermic circulatory arrest

Using deep hypothermic circulatory arrest, thoracic aorta diseases and complex heart diseases can be subjected to corrective procedures. However, mechanisms underlying brain protection during deep hypothermic circulatory arrest are unclear. After piglet models underwent 60 minutes of deep hypothermic circulatory arrest at 14°C, expression of microRNAs(miRNAs) was analyzed in the hippocampus by microarray. Subsequently, TargetScan 6.2, RNA22 v2.0, miRWalk 2.0, and miRanda were used to predict potential targets, and gene ontology enrichment analysis was carried out to identify functional pathways involved. Quantitative reverse transcription-polymerase chain reaction was conducted to verify miRNA changes. Deep hypothermic circulatory arrest altered the expression of 35 miRNAs. Twenty-two miRNAs were significantly downregulated and thirteen miRNAs were significantly upregulated in the hippocampus after deep hypothermic circulatory arrest. Six out of eight targets among the differentially expressed miRNAs were enriched for neuronal projection(cyclin dependent kinase, CDK16 and SLC1 A2), central nervous system development(FOXO3, TYRO3, and SLC1 A2), ion transmembrane transporter activity(ATP2 B2 and SLC1 A2), and interleukin-6 receptor binding(IL6 R)– these are the key functional pathways involved in cerebral protection during deep hypothermic circulatory arrest. Quantitative reverse transcription-polymerase chain reaction confirmed the results of microarray analysis. Our experimental results illustrate a new role for transcriptional regulation in deep hypothermic circulatory arrest, and provide significant insight for the development of miRNAs to treat brain injuries. All procedures were approved by the Animal Care Committee of Xuanwu Hospital, Capital Medical University, China on March 1, 2017(approval No. XW-INI-AD2017-0112).

Wumei pills attenuates 5-fluorouracil-induced intestinal mucositis through Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB pathway and microbiota regulation

BACKGROUND Radiotherapy and chemotherapy can kill tumor cells and improve the survival rate of cancer patients.However,they can also damage normal cells and cause serious intestinal toxicity,leading to gastrointestinal mucositis[1].Traditional Chinese medicine is effective in improving the side effects of chemotherapy.Wumei pills(WMP)was originally documented in the Treatise on Exogenous Febrile Diseases.It has a significant effect on chronic diarrhea and other gastrointestinal diseases,but it is not clear whether it affects chemotherapy induced intestinal mucositis(CIM).AIM To explore the potential mechanism of WMP in the treatment of CIM through experimental research.METHODS We used an intraperitoneal injection of 5-fluorouracil(5-Fu)to establish a CIM mouse model and an oral gavage of WMP decoction(11325 and 22650 mg/kg)to evaluate the efficacy of WMP in CIM.We evaluated the effect of WMP on CIM by observing the general conditions of the mice(body weight,food intake,spleen weight,diarrhea score,and hematoxylin and eosin stained tissues).The expression of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),IL-1β,and myeloperoxidase(MPO),as well as the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB(TLR4/MyD88/NF-κB)signaling pathway proteins and tight junction proteins(zonula occludens-1,claudin-1,E-cadherin,and mucin-2)was determined.Furthermore,intestinal permeability,intestinal flora,and the levels of short-chain fatty acids(SCFA)were also assessed.RESULTS WMP effectively improved the body weight,spleen weight,food intake,diarrhea score,and inflammatory status of the mice with intestinal mucositis,which preliminarily confirmed the efficacy of WMP in CIM.Further experiments showed that in addition to reducing the levels of TNF-α,IL-1β,IL-6,and MPO and inhibiting the expression of the TLR4/MyD88/NF-κB pathway proteins,WMP also repaired the integrity of the mucosal barrier of mice,regulated the intestinal flora,and increased the levels of SCFA(such as butyric acid).CONCLUSION WMP can play a therapeutic role in CIM by alleviating inflammation,restoring the mucosal barrier,and regulating gut microbiota.

Mosaic structure ZnO formed by secondary crystallization with enhanced photocatalytic performance

Zinc acetate is used as a raw material to synthesize the desired ZnO in hot solvent by controlling the amount of citric acid(CA)added.Notably,the amount of CA added has a significant relationship with the control of the morphology of ZnO.Spherical ZnO wrapped in nanosheets is synthesized through the secondary crystallization of Zn^(2+).The optical properties of the ZnO sample are tested through the degradation of organic pollutants.Notably,the photocatalytic properties of ZnO vary with the different amounts of CA added.Exposure of the active crystal face increases the photocatalytic activity of ZnO.In addition,the number of defects on the surface of the ZnO sample increases because of its large specific surface area,thus changing the bandgap of ZnO.Therefore,the resulting sample can respond under visible light.

Anatomical Evidence for the Neural Connection from the Emotional Brain to Autonomic Innervation in the Anterior Chamber Structures of the Eye

Objective Previous studies have shown that the autonomic nervous system(ANS),which can be affected by emotions,is important in the occurrence or progression of glaucoma.The autonomic innervation distributed in the anterior chamber(AC)structures might play an efferent role in the neural regulation of intraocular pressure(IOP).This study aimed to investigate the anatomic neural connection from the emotional brain to autonomic innervation in the AC.Methods A retrograde trans-multisynaptic pseudorabies virus encoded with an enhanced green fluorescent protein(PRV531)and non-trans-synaptic tracer FAST Dil were injected into the right eye of mice,respectively.Fluorescent localization in the emotional brain and preganglionic nuclei was studied.Five and a half days after PRV531 injection into the right AC,fluorescent signals were observed in several emotional brain regions,including the amygdala,agranular insular cortex,lateral septal nuclei,periaqueductal gray,and hypothalamus.Autonomic preganglionic nuclei,including Edinger-Westphal nucleus,superior salivatory nucleus,and intermediolateral nucleus,were labeled using PRV531.Results The sensory trigeminal nuclei were not labeled using PRV531.The fluorescence signals in the nuclei mentioned above showed bilateral distribution,primarily on the ipsilateral side.Seven days after injecting FAST Dil into the AC,we observed no FAST Dil-labeled neurons in the central nervous system.Conclusion Our results indicate a neural connection from the emotional brain to autonomic innervation in the AC,which provides anatomical support for the emotional influence of IOP via the ANS.

Effect of insulin in combined with Chinese medicine formulae on the serum Mg2+ and visfatin levels, maternal and infant outcome in pregnant women with gestational diabetes mellitus

Objective:To explore the effect of insulin in combined with Chinese medicine formulae on the serum Mg2+ and visfatin levels, maternal and infant outcome in pregnant women with gestational diabetes mellitus (GDM).Methods:A total of 108 pregnant women with GDM who were admitted in our hospital were included in the study and randomized into the observation group (n=55) and the control group (n=53). The patients in the two groups were given diet control, exercise therapy, and subcutaneous injection of insulin. On this basis, the patients in the observation group were given self-made Chinese medicine formulae, continuously for 2 weeks. The blood sugar level, and serum Mg2+ and visfatin (VF) levels before treatment and before delivery in the two groups were detected. The maternal and infant outcome in the two groups was evaluated.Results:The serum HbA1c, FPG, 1 h PBG, 2 h PBG, and VF levels before delivery in the two groups were significantly reduced when compared with before treatment (P<0.05), while the serum Mg2+ level was significantly elevated when compared with before treatment (P<0.05). The improvement of the above indicators before delivery in the observation group was more significant when compared with the control group (P<0.05). The occurrence rate of cesarean section, premature delivery, gestational hypertension, fetal distress, and macrosomia in the observation group was significantly lower than that in the control group (P<0.05).Conclusions:Insulin in combined with self-made Chinese medicine formulae can effectively control the blood sugar level in pregnant women with GDM, and improve the maternal and infant outcome.

Mechanism of cryogenic,solid solution and aging compound heat treatment of die-cast Al alloys considering microstructure variation

To develop a new compound heat treatment process for improving the mechanical properties of die-cast Al alloys,this study investigated the effects of cryogenic,solution and aging compound treatment on the microstructure and mechanical properties of die-cast Al alloys.The characterization methods used were optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),electron backscatter diffraction(EBSD),and tensile tests;and the Image Pro Plus software was used for statistical analysis.The results indicated that compared with T6 heat treatment,the compound heat treatment process consisting of cryogenic treatment(-196.C for 12 h),solid solution treatment(476.C for 22 min),and aging(159.C for 403 min)significantly enhanced the mechanical properties of the diecast Al alloys.For instance,the tensile strength increased from 224.3 to 249.5 MPa;the hardness increased from HV110.5 to HV 124.6,and the elongation increased from6.28%to 7.72%,which in relative terms corresponds to11.2%,12.8%and 22.9%,respectively.The compound heat treatment process of the alloy led to significant refinement of its a-Al phases.In addition,Si phases tended to be more ellipsoidal or granular,while the tips of Fecontaining phases became rounded,which played a key role in enhancing the mechanical properties and microstructure stability of the alloys.

Micromechanical behavior of TiNb/NiTi composite during a pre-straining process:an in situ synchrotron investigation

The micromechanical behavior of a recently developed TiNb/NiTi composite during a pre-straining process was investigated to broaden the understanding of deformation mechanisms of the martensitic-transforming composites.It was found that during loading,besides inherent elastic elongation,the TiNb/NiTi composite also experienced two different categories of stress-induced martensitic transformations(SIMTs,including B2→B19’andβ→α")and slight plastic deformation.Upon the following unloading,this composite recovered elastically,and underwent simultaneously a fully reversibleα"→βSIMT as well as a partially reversible B19’→B2 SIMT.It was the incomplete B19’→B2 SIMT and the permanent plastic deformation that led to the~4.6%macroscopic residual strain after unloading.In the entire loading-unloading procedure,the growth and shrinkage of(001)compound twins in B19’martensite also contributed to the large nearlinear-elastic deformation of the present composite.

Near-Iinear elastic deformation behavior of a novel Zr-Ti-Nb-Sn alloy with multi-phase microstructures ofβ,α"andα'phases

In this work,a multi-phase Zr-30Ti-7Nb-4Sn alloy with large near-linear elastic deformability was prepared by the solution treatment plus pre-straining(S TP)treatment,and the underlying mechanism accountable for the near-linear elastic deformation was systematically clarified.It was found that the Zr-30Ti-7Nb-4Sn alloy was composed ofβ,α″andα′phases,and numerous dislocations were formed in the alloy specimen after STP treatment.With the retarding effect of high-density dislocations,the stress-induced martensitic(SIM)transformation fromβtoα″phases took place homogeneously and continuously during loading,in conjunction with the occurrence of elastic deformation ofβ,α″andα′phases.Under the entire tensile procedure,no observable phase transformation occurred betweenα′martensite andβphase.Consequently,the near-linear elastic deformation capability in STP Zr-30Ti-7Nb-4Sn alloy is mainly ascribed to the coupling actions of consecutiveβ→α″SIM transformation and intrinsic elastic deformation ofβ,α″andα′phases.These experimental results provide a basis for designing and developing novel multi-phase Zr-based alloys that possess large near-linear deformability.

Improved survival ratios correlate with myeloid dendritic cell restoration in acute-on-chronic liver failure patients receiving methylprednisolone therapy

Acute-on-chronic liver failure （ACLF） is a severe life-threatening complication. Liver transplantation is the only available therapeutic option; however, several limitations have restricted its use in patients. The use of corticosteroids as an optional therapy for ACLF has received a great deal of interest. The rationale behind its use is the possible role of the immune system in initiating and perpetuating hepatic damage. In order to assess the relationship between myeloid dendritic cells （mDCs） and the efficacy of methylprednisolone （MP） treatment for hepatitis B virus （H BV）-associated ACLF patients, we recruited 30 HBV-associated ACLF patients who had received MP treatment at lO-day intervals; 26 patients received conservative medical （CM） management as a control. The functionality of DC subsets was lower in these ACLF patients compared with healthy subjects. In addition, compared with survivors, dead/transplanted patients had lower functional mDC in both groups. Furthermore, a decreased numbers of mDC at baseline was associated with high mortality of ACLF patients. Importantly, MP treatment resulted in a significant decrease in 28-day mortality, and all MP patients exhibited an initial rapid decrease in circulating mDC numbers within 10 days of MP treatment. Subsequently, MP survivors displayed a continuous increase in mDC numbers accompanied by a decrease in total bilirubin levels by more than 30%. However, MP dead/ transplanted patients lacked these sequential responses compared with survivors. This evidence suggests strongly that the higher mDC numbers at baseline and the recovery of mDC number at the end of treatment may represent a prognostic marker for favorable response to corticosteroid treatment in ACLF patients.

In situ synchrotron X-ray diffraction analysis of deformation behavior of a Nb/NiTi composite for biomedical applications

The deformation behavior involved in Nb/NiTi composite for biomedical applications within a large macroscopic strain range was investigated by tensile loading-unloading test and in situ synchrotron X-ray diffraction(SXRD).Experimental results show that during loading,the Nb/NiTi composite experiences the elastic elongation of B2-NiTi austenitic,B19’-NiTi martensitic and β-Nb phases,B2→ B19’ stress-induced martensitic(SIM) transformation and tensile plastic deformation of β-Nb phase.During unloading,the deformation behavior involved in Nb/NiTi composite includes the elastic recovery of B2-NiTi austenitic,B19’-NiTi martensitic and β-Nb phases,reverse phase transformation B19’→B2 and compressive deformation of p-Nb phase.The martensitic transformation in this composite is almost reversible and occurs in a localized manner.These results might contribute to a comprehensive understanding of the deformation mechanism involved in Nb/NiTi composite and shed some light on design and development of novel composites with a combination of good biocompatibility and excellent superelasticity for biomedical applications.

Uniaxial tensile deformation behavior of a sandwich-like structural TiNb-NiTi composite for biomedical applications

The uniaxial tensile deformation behavior of a sandwich-like structural TiNb-NiTi composite was investigated by uniaxial tensile test and in situ high-energy synchrotron X-ray diffraction(SXRD).It is found that below 1.2%macroscopic strains,the elastic deformations of the B2,β,B19'andα"phases take place in the TiNbNiTi composite.During the subsequent loading,theβ→α"and B2→B19'stress-induced martensitic transformations(SIMTs)occur within the macroscopic strains of 0.5%-4.2%and the macroscopic strains of 0.7%-6.2%,respectively.At the macroscopic strain of about 4.2%,the outer TiNb layer of the TiNb-NiTi composite experiences a partial fracture,as proved by the disappearance of(040)_(α")and a sudden jump in the(110)_(B19')d-spacing caused by load transfer.With further uniaxial tensile deformation,the TiNbNiTi composite finally fractures at a strain of~6.2%.Our results might provide some valuable information for understanding the deformation behavior of novel sandwich-like structural shape memory composites in more depth.