放电等离子烧结制备纯T′相YSZ陶瓷的研究

采用经过等离子喷涂处理的8%(质量分数,下同)YSZ纯T′相陶瓷粉体,经过高能球磨和高能搅拌磨处理后分别在1400、1450、1500、1600℃下进行放电等离子烧结,保温5～15min,得到不同显微结构的陶瓷样品。XRD分析结果显示其仍保持纯T′相。通过对其粉体和烧结后样品显微形貌的分析,探讨晶粒长大与烧结条件的关系,从而得到最优的YSZ纯T′相陶瓷制备工艺为1450℃/5min。

等离子喷涂用纳米结构T'相8YSZ球形喂料及应用展望

目的通过纳米粉体再造粒技术制备出等离子喷涂用高性能纳米结构非平衡转变四方相ZrO2-8%(8YSZ)球形喂料,以满足高端装备的需求。通过调控再造粒工艺以期应用于"两机"及陶瓷3D打印的耗材。方法以纳米8YSZ粉体为原料,通过纳米粉体再造粒技术制备出等离子喷涂用纳米结构8YSZ喂料。利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)研究了纳米结构8YSZ喂料的表面形貌、晶粒尺寸以及相结构。同时测定了纳米结构8YSZ喂料的松装密度、振实密度、流动性等物性参数。结果制备的纳米结构8YSZ喂料呈球形形貌,喂料表面光滑且内部致密,喂料处于自由流状态且其粒度满足等离子喷涂要求。在纳米粉体再造粒过程中,纳米结构8YSZ喂料晶粒尺寸没有明显长大,相结构为非平衡转变四方相即T′相。结论通过对纳米粉体再造粒工艺的调控,可以制备出粒度分布与组织结构可控的高性能纳米结构T'相de8YSZ球形喂料。制备出的高性能喂料有望用于航空发动机和燃气轮机(两机)等高端装备以及用于陶瓷3D打印的耗材。

Al-Zn-Cu系200℃低铜侧的相平衡

熔制了Al Zn Cu系的13个不同成分的合金,并进行了组织均匀化和平衡冷却至200℃的缓冷处理。通过显微组织观察、X射线衍射分析和电子探针微区成分分析,测定了这13个合金的相组成及成分。结果表明,在200℃时,富铝角α相的Zn、Cu、Al含量(摩尔分数)分别为6.7%、2.0%和91.3%,确定了T′相的成分范围以及Al2Cu3相中Zn的溶解度(摩尔分数)小于4.4%,绘制出了Al Zn Cu系200℃低Cu侧的等温截面相图。

Al-Zn-Cu系室温低Cu侧的相平衡关系

通过显微组织观察和X射线衍射分析,结合电子探针分析,确定了在Al Zn Cu系中所设计的14个不同成分的合金经充分成分均匀化和平衡阶梯冷却至20℃的合金相组成及成分·在其中11个合金中发现了T′相(Al4Cu3Zn)的存在,测定了4个合金中的T′相的成分,并得到了新的相平衡关系·从另一个侧面证实了T′相在室温时(20℃)是可以稳定存在的,同时说明美国金属学会1997年出版的相图集中的Al Zn Cu系20℃等温截面相图在低Cu侧的相关系上是不正确的·

Microstructure characterization on Mg-2Nd-4Zn-1Zr alloy duringheat treatment

The microstructures of Mg-2Nd-4Zn-1Zr alloy in the as-cast state and after heat treatment were investigated. Several kinds of secondary phases were found and characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. In the as-cast alloy, the existing eutectic compounds are Mg-Nd-Zn ternary phases： T phases and W phases. After the heat treatment, with increasing the temperature or time, it was found that T phase almost dissolved into the α-Mg matrix, while a large amount of W phase remained in the matrix. On the other hand, with prolonging the time, the morphology of the phase changed from continuous network to the spherical shape along the grain boundary. The density of the W phase gradually decreased and finally it was coarsened and stabilized in the treatment process.

TEM microstructure of rapidly solidified Mg-6Zn-1Y-1Ce alloy

Rapidly solidified（RS） Mg-6Zn-1Y-1Ce ribbons were prepared by single roller melt-spinning technique.Transmission electron microscopy and energy dispersive X-ray spectroscopy were employed to characterize the microstructure of RS ribbons.The results show that there is high density of particles distributed within grains and at grain boundaries in the region near wheel side.The particle density is decreased in the middle region and free surface region.The alloy is predominantly composed of supersaturated--Mg solid solution,T phase and W phase;meanwhile,a few icosahedral quasicrystalline and Mg4Zn7 particles are also observed.The T phase is confirmed having a body-centered orthorhombic structure that is transformed from the body-centered tetragonal structure Mg12Ce phase due to the partial substitution of Mg atoms by Zn.

Comprehensive Understanding of Immune Cells in The Pathogenesis of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease(NAFLD)is the most common chronic liver disease,defined by several phases,ranging from benign fat accumulation to non-alcoholic steatohepatitis(NASH),which can lead to liver cancer and cirrhosis.Although NAFLD is a disease of disordered metabolism,it also involves several immune cell-mediated inflammatory processes,either promoting and/or suppressing hepatocyte inflammation through the secretion of pro-inflammatory and/or anti-inflammatory factors to influence the NAFLD process.However,the underlying disease mechanism and the role of immune cells in NAFLD are still under investigation,leaving many open-ended questions.In this review,we presented the recent concepts about the interplay of immune cells in the onset and pathogenesis of NAFLD.We also highlighted the specific non-immune cells exhibiting immunological properties of therapeutic significance in NAFLD.We hope that this review will help guide the development of future NAFLD therapeutics.

Expression of nitric oxide synthase in T-cell-dependent liver injury initiated by ConA in Kunming mice

Objective: To investigate whether nitric oxide synthase (NOS) is expressed in T-cell-dependent liver injury initiated by concanavalin A (ConA) in Kunming mice and study the possible effect of nitric oxide(NO) on liver injury models. Methods: Liver injury in Kunming mice was induced by administration of ConA through tail vein. Expression of NOS in the liver was detected by NADPH diaphorase staining method. The possible effect of NO on liver injury models was obtained by L-NAME injection to suppress synthesis of NO. Results: NOS has a strong expression in hepatocytes after ConA injection, especially in those close to the central vein, while only a weak expression was found in the epithelial cells in control group. Liver injury became more serious when NO synthesis was inhibited by L-NAME, accompanied by great malondialdehyde(MDA) increase in serum and severe intrahepatic vascular thrombosis. Conclusion: NOS markedly expressed in ConA-induced liver injury, which may subsequently promote nitric oxide synthesis. Increasement of nitric oxide has a protective effect on ConA-induced liver injury.

Abdominal computed tomography in refractory coeliac disease and enteropathy associated T-cell lymphoma

AIM： To evaluate computed tomography （CT） findings, useful to suggest the presence of refractory celiac disease （RCD） and enteropathy associated T cell lymphoma （EATL）. METHODS： Coeliac disease （CD） patients were divided into two groups. Group Ⅰ ： uncomplicated CD （n = 14） and RCD type Ⅰ （n = 10）. Group Ⅱ ： RCD type Ⅱ （n = 15） and EATL （n = 7）. RESULTS： Both groups showed classic signs of CD on CT. Intussusception was seen in 1 patient in group Ⅰ vs 5 in group Ⅱ （P = 0.06）. Lymphadenopathy was seen in 5 patients in group Ⅱ vs no patients in group Ⅰ （P = 0.01）. Increased number of small mesenteric vessels was noted in 20 patients in group Ⅰ vs Ⅱ in group 11 （P = 0.02）. Eleven patients （50%） in group 11 had a splenic volume 〈 122 cm^3 vs 4 in group Ⅰ （14%）, 10 patients in group Ⅰ had a splenic volume 〉 196 cm^3 （66.7%） vs 5 in group Ⅱ （33.3%） P = 0.028. CONCLUSION： CT scan is a useful tool in discriminating between CD and （Pre） EATL. RCD Ⅱ and EATL showed more bowel wall thickening, lymphadenopathy and intussusception, less increase in number of small mesenteric vessels and a smaller splenic volume compared with CD and RCD Ⅰ.

Expression of a soluble form of CTLA4 on macrophage and its biological activity

Interaction between cytotoxic T lymphocyte-asso-ciated antigen-4 (CTLA4, CD152) and B7 molecules (B7-1and B7-2) is of importance in the cellular events of lym-phocyte, including antigen-specific T-cell activation andinduction of autoreactive T-cell. We describe here the firstintroduction of a murine soluble CTLA4 gene, CTLA4Ig,to Mm1 cells, a macrophagic cell line. CTLA4Ig waJssuccessfully expressed on Mm1 cells and the expressedCTLA4Ig was found to be functionally active in their bind-ing to B7 molecules by flow cytometry and immunofluo-rescence studies- The biological activity of CTLA4Ig fromthe transfected Mm1 cells was studied and showed in-hibitory activity on mixed lymphocyte culture. A highCTLA4Ig producing macrophagic cell line was obtained.As Mm1 cells were regarded as difficult for gene transfec-tion and there had so far been no report on expression ofCTLA4Ig gene on Mm1 cells, these results suggested thatthe CTLA4Ig expressing Mm1 cells could be useful forExpression of CTLA4 on Mml and its biological activityanalysis of CTLA4 and B7 molecule interaction in bothmacrophage and T-cell.

Basis Set Extrapolation for the High Resolution Spectroscopy

Valence and all electron correlation energies of a large set of atoms and molecules with structural motifs from amino acids and peptides at their equilibrium as well as non-equilibrium geometries are calculated at the levels of MP2, RI-MP2, and CCSD （T） with Dunnings sequential correlation consistent basis sets. A two point basis set extrapolation scheme for correlation energies to the complete basis set limit based on only DZ （double-zeta） and TZ （triple-zeta） results is presented and analyzed. We show that this basis set extrapolation scheme reduces the computational cost by two to three orders of magnitude to obtain the same accuracy as simpler extrapolations from higher order basis set computations.

No association of the cytotoxic T-lymphocyte associated gene CTLA4 +49A/G polymorphisms with Crohn's disease and ulcerative colitis in Hungarian population samples

AIM： The goal of the current work was to analyse the prevalence of the ＋49A/G variant of the cytotoxic T-lymphocyte antigen 4 gene （CTLA4） in Hungarian patients with Crohn＇s disease （CD） and ulcerative colitis （UC）. METHODS： A total of 130 unrelated subjects with CD and 150 with UC, and 170 matched controls were genotyped for the single nucleotide polymorphism （SNP）. The genotypes were determined by using PCR/RFLP test. RESULTS： The G allele frequency and the prevalence of the GG genotype were 38.1% and 12.3% in the CD group, 40.6% and 18.6% in the UC patients, and 37.4% and 15.9% in the control group, respectively. CONCLUSION： The results of the current study show that carriage of the ＋49G SNP in heterozygous or in homozygous form does not confer risk either for CD or for UC in the Hungarian population.

Diagnosis of uremia patients based on color space

Since traditional nail diagnosis is susceptible to objective factors such as illumination,medical experience,etc.,a nail diagnosis system of traditional Chinese medicine which combines objective nail image acquisition with information analysis is proposed and applied to the clinical research of nail diagnosis of uremia patients.Fifteen nail pictures of uremic patients were collected and segmented.The color information of nails was extracted.The relationship between the hemoglobin values of uremic patients and the values of color space before and after maintenance hemodialysis was analyzed by correlation analysis and multiple regression analysis.The experimental results show that the hemoglobin value of uremic patients have certain correlations with multiple color channels;before and after dialysis,there are significant changes in multiple channels;and the related multiple regression equation is established.

Cytotoxic T lymphocyte associated antigen-4 gene exon 1A49→G polymorphisms confer susceptibility to idiopathic dilated cardiomyopathy

Autoimmune mechanisms, including cellular and humoral immune, are likely to participate in the pathogenesis of at least a subgroup of idiopathic dilated cardiomyopathy （IDC）, in which cellular immune-mediation plays a more important role. Cytotoxic T lymphocyte associated antigen-4 （CTLA-4） is the major negative regulatory factor of cellular immunity. This study was conducted to investigate the association of CTIA-4 gene exon 1 A49→G polymorphism with susceptibility to IDC in Han Chinese and its influences on serum soluble CTIA-4 （sCrLA-4） and Th1/Th2 cytokine bias. Polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） techniques were used to analyze the dimorphism of CTL4-4 exon 1 in the unrelated Han ethnic population in Heilongjiang Province （ including 48 IDC patients and 50 normal controls）. Serum sCTLA-4, IFN-γ and IL-4 were evaluated by ELISA, with the ratio of IFN-γ/IL-4 as indicator for Th1/Th2 bias. Compared with controls, the frequencies of GG genotype （0.6042 and 0.3600, P = 0.012） and the G allele （0.7396 and 0.5600, P = 0.008） were significantly increased in IDC patients. Increased serum sCTIA-4 was found in the 1DC group compared with the controls [ （ 1.87 ± 1.06） μg/L vs. （0.54 ± 0.19） 〉g/L, P 〈 0.05 ~. 1FN-7 was much lower in IDC patients than that of the controls [ （ 16.38 ± 6.25） ng/L vs. （29.81 ± 10.66） ng/L （P 〈 0.05）~., whereas no statistical difference of IL-4 was found between the two groups I （12.85 ± 1.86） ng/L vs. （12.11 ± 2.76） ng/L], so the ratio of IFN-γ/IL-4 declined significantly （ 1.63 ± 0.50 vs. 3.01 ± 0.89, P 〈 0.05）. Linear regression analysis manifested a significant interrelationship between the GG genotype, G allele frequencies and serum sCTLA-4, IFN-γ/IL-4 in the IDC group （ r = 0.57, P = 0. 021 and r = 0.32, P = 0. 036）. CTLA-4 gene A49→G substitution was associated with an increased IDC risk, which implicated that the CTLA-4 gene exon 1 may have a considerable role in autoimmune cardiac damage, possibly via a Thr→Ala change in signal peptide, which influences the protein synthesis and modification processes, with a result of functional alteration of sCTLA-4. The bias of Th1/Th2 paradigm was associated with the increased sCTIA-4 under certain background of immunogenetics.

Spin Polarizations of Electron with Rashba Couplings in T-Shaped Devices:A Finite Element Approach

A generalized finite element formulation is proposed for the study of the spin-dependent ballistic transport of electron through the two-dimensional quantum structures with Rashba spin-orbit interactions （SOI）. The transmission coefficient, conductance, the total and local polarization are numerically calculated and discussed as the Rashba eoefficient, the geometric sizes, and incident energy are changed in the T-shaped devices. Some interesting features are found in the proper parameter regime. The polarization has an enhancement as the Rashba coefficient becomes stronger. The polarization valley is rigid in the regime of the conductance plateaus since the local interference among the polarized multi-wave modes. The Rashba interactions coupling to geometry in sizes could form the structure-induced Fano-Rashba resonance. In the wider stub, the localized spin lattice of electron could be produced. The conductance plateaus correspond to weak polarizations. Strong polarizations appear when the stub sizes, incident energy, and the Rashba coupling coefficient are matched. The resonances are formed in a wide Fermi energy segment easily.

Theoretical Analysis of an Anion-πComplex:I-·C6F6

Recently,AnstÖter and co-workers[J.Am.Chem.Soc.141,6132(2019)]have provided the first photoelectron spectroscopic determination of the anion-πbond strength(De)using iodide-hexafluorobenzene(I-·C6F6)as the archetypical system.In combination with an equation-of-motion coupled cluster theory,namely EOM-IP-CCSD(d T),using Dunning’s aug-cc-p VDZ(a VDZ)basis set,Dein I-·C6F6 was found to be-0.53 e V with an uncertainty less than±0.03 e V.The interaction was claimed to arise for a large part from correlation forces(41%)with only a 23%contribution from electrostatic forces.In the present work,we performed the coupled-cluster with single and double and perturbative triple excitations,CCSD(T),calculations.We found that CCSD(T)/a VDZ can have an uncertainty up to 0.113 e V due to the basis set incompleteness.Our calculations disclosed that the previous calculations on the electrostatic contribution are concealed by the contributions from the exchange and Pauli repulsion.The electrostatic contribution is actually determinant,being more than double of the correlation contribution in the I-·C6F6 complex at the equilibrium binding distance.

Safety of anti-tumor necrosis factor therapy in inflammatory bowel disease

Inflammatory bowel disease (IBD), in particular Crohn's disease refractory to conventional therapy, fistulizing Crohn's disease and chronic active ulcerative colitis, generally respond well to anti-tumor necrosis factor (TNF) therapy. However, serious side effects do occur, necessitating careful monitoring of therapy. Potential side effects of anti-TNF therapy include opportunistic infections, which show a higher incidence when concomitant immunosuppression is used. Furthermore, antibody formation against anti-TNF is associated with decreased efficacy and an increased frequency of infusion reactions. The hypothesis of a slightly increased risk of lymphomas in IBD patients treated with anti TNF-therapy is debatable, since most studies lack the specific design to properly address this issue. Alarmingly, the occurrence of hepatosplenic T-cell lymphomas coincides with combined immunosuppressive therapy. Despite the potential serious side effects, anti-TNF therapy is an effective and relatively safe treatment option for refractory IBD. Future research is needed to answer important questions, such as the long-term risk of malignancies, safety during pregnancy, when to discontinue and when to switch anti-TNF therapy, as well as to determine the balance between therapeutic and toxic effects.

ENDOGENOUS EXPRESSION AND HLA STABILIZATION ASSAY OF PLASMODIUM FALCIPARUM CTL EPITOPE MINIGENE IN HUMAN HLA- A2.1 AND HLA- B51 CELLS

To evaluate the Plasmodium falciparum CTL epitope vaccines in HLA class I allele specific human cell lines that have high frequency among Chinese population. Methods. Synthesized oligonucleotides encoding for P.f. CTL epitope genes, constructed eukaryotic expression plasmids, transfected the minigenes into HLA class I allele specific human cell lines and identified endogenous expressing of the minigenes by RT- PCR and HLA stabilization assay. Results. Two mini- genes encoding Plasmodium falciparum CTL epitopes were designed and cloned, respectively, into an eukaryotic expressing vector to form TR26 which was restricted to HLA- B51, SH6 which was restricted to HLA- A2.1, and TS, which had the two aforementioned mini- genes fused in tandem. All of these CTL epitope genes were transfected and endogenously expressed in respective cell lines containing appropriate HLA molecules. The obviously increased expressions of HLA class I molecules were detected in the transfected cell lines. It was demonstrated that the two discrete Plasmodium falciparum epitope genes were effectively processed and presented, and the close proximity of the two epitope genes in one chain as in mini- gene TS did not interfere with the processing and presenting of each epitope gene in corresponding cell line. Conclusion. A successful expression and presentation of multiple CTL epitope mini- gene in MHC class I allele specific human cell lines were demonstrated by an in vitro assay, which could be corresponding to the vaccination of CTL vaccines in people with different MHC I molecules. This work also suggested the possibility of constructing a multiple CTL epitope plasmodium falciparum DNA vaccine that could cover most of Chinese population.

压力及高压增氧对La_(2-x)Sm_xCuO_4结构及输运性质的影响

对常压、高压、高压增氧条件下合成的La2-xSmxCuO4(0≤x≤2.0)结构进行了研究。常压合成样品清晰地反应出样品由T→T+T′→T′相的变化,其中,T相:0<x<0.2;T+T′相:0.2<x<1.0;T′相:1.0<x<2.0。随着x的增加,晶胞参数呈现下降趋势。高压样品没有明显出现T+T′相的过渡阶段,而高压增氧样品更表现为稳定的T相。并且高压、高压增氧样品比常压合成样品含有较多的缺陷。SEM照片显示高压和高压增氧样品比常压合成样品具有更高的质密度,而高氧压的过程也使晶粒变得粗糙和易碎。只有T相高氧压合成样品呈现金属性电阻行为,在x≤0.5时,低温下出现超导电性,并且与交流磁化率结果相吻合。

A Mathematical Model of Breast Cancer and Mediated Immune System Interactions

Mathematical model that describes breast cancer and immune interactions were presented using system of differential equations to provide analytic and nnmeric framework of cancer-immune dynamics. Four types of immune cells-CTLs （cytotoxic T lymphocytes）, macrophages, NK （natural killer） and helper T cells-known to play the most significant roles in developing breast cancer immunity were modeled using differential equations. The model was then applied to different cancer growth rates and simulated using MATLAB software tool. The parameters of the model were based on experimental and clinical results from published articles. Results supported clinical studies that maximal breast cancer immunity depends mostly on each of the four immune cell types chosen. It was observed that for a given breast cancer growth rate, there was an optimal activation that maximized the response of the immune system. The effectiveness of the immune system resulted in the decrease in breast cancer killing rates. These results highlighted the importance of immune system activations in breast cancer development and treatment. Therefore, the model and its simulation provided a robust framework to better understand breast cancer progression and response to the immune system.