Structural and magnetic properties of LaCrO3 half-doped with Al

Structural and magnetic properties of LaCrO₃ half-doped with Al are reported in this work. Pure and half-doped samples were prepared by combustion synthesis using urea as fuel. The crystal structure was investigated by X-ray diffraction and Rietveld analysis. A structural phase transition caused by a decrease of the chemical pressure was observed. The scanning electron microscopy (SEM) images show the formation of porous samples with particles of irregular morphologies. A quantitative Energy-dispersive X-ray spectroscopy (EDS) analysis on the surface indicates the inclusion of the Al on the structure. However, a small deficiency of La and Al was observed. Magnetization measurements as a function of temperature reveal an antiferromagnetic order in both samples. A large decrease of T_N (Néel temperature) and a reduction of the frustration factor is observed in the sample doped with Al. The magnetic isothermal at 5 K shows a typical antiferromagnetic behavior with a slightly spin canting for the doped sample.     

医学图像配准技术进展

医学图像配准对提高临床诊断治疗、病情监测、外科手术水平等有积极作用.以一个医学图像配准配框架为主线,综述了配准框架各模块所涉及的经典算法、新技术,并对相关性能进行了分析.此外,还涉及医学图像配准开发平台、测试数据库及评估标准等.全面地总结了医学图像配准技术的最新进展.     

医学图像融合质量评价模型

针对医学领域里的图像融合质量评价问题,提出一种基于底层视觉特征的评价模型.该模型通过综合测评融合图像的清晰度、纹理和边缘信息的完整程度判断其质量.并通过调整参数协调上述三项指标在评价过程中的决策比重.使之既符合人类的视觉感受,又能反映不同应用场合对融合图像质量的特殊要求.实验表明,模型兼顾了整体性能和个性化需求,能够胜任医学领域对图像融合质量评价的任务.     

Cement formation by microbial poly(γ-glutamic acid) and fluoroalumino-silicate glass

The feasibility of using microbial poly(γ-glutamic acid) (γ-PGA) in cement formation was analyzed. FT–IR and elemental analyses by energy-dispersive spectroscopy (EDS), indicate that calcium and aluminum carboxylates are formed after the reaction of γ-PGA with fluoroalumino-silicate glass powder. The effect of the formulation variables, i.e., (polymer + glass) / liquid ratio (P / L), glass / polymer ratio (G / P), the average glass particle size and the molecular mass of γ-PGA, on the compressive strength is discussed. A maximum compressive strength value of 130 MPa was obtained when cement samples were aged for 7 days. The compressive strength was achieved with a P / L ratio of 2.5 g/ml, a G / P ratio of 2.5 : 1, an average glass particle size of 1 μm and a γ-PGA molecular mass (M ¯w) of 115 000.     

工艺参数对Ni-Cr合金与陶瓷界面组织性能的影响

通过改变烤瓷温度及烤瓷时间,研究了金-瓷界面的力学性能和微观组织的变化规律.结果表明,金-瓷界面反应非常复杂,金-瓷界面处的物相主要有SnO2,SnCr0.14Ox,AlNi3及KAlSi2O6的复合氧化物等.烤瓷工艺参数变化直接影响金-瓷界面反应产物种类、数量及分布,最终决定了金-瓷界面结合强度.在一定范围内,随烤瓷温度的提高和烤瓷时间的延长,反应层变宽,金-瓷界面由突变型界面转变为化合物型,对提高金-瓷界面结合强度将起到非常重要的作用.当采用烤瓷温度T=960℃,烤瓷时间t=2.5 min时,金-瓷界面抗剪强度可达到42.7 MPa.     

吴茱萸碱体外抗肿瘤作用

目的:研究吴茱萸碱(evodiamine, Evo)的体外抑瘤谱, 并初步探讨其抗肿瘤的作用机制。方法:MTT 法测定Evo 对肿瘤细胞的生长抑制情况;采用光镜和电镜观察Evo 对人肺腺癌细胞SPCA 1形态的影响;流式细胞术检测Evo 对SPC-A 1细胞的抑制作用和细胞周期的影响。结果:Evo对SPC-A 1等10种肿瘤细胞有选择性的生长抑制作用, 5 μg/mL 的Evo 处理后, 细胞变圆, 体积变小, 分泌颗粒增多, 细胞折光性下降, 大部分细胞脱壁。透射电镜下可见细胞表面微绒毛消失、核染色质浓集、边聚, 核碎裂, 并可见凋亡小体;流式细胞仪检测Evo 作用后, G0G1期和S 期细胞减少, 大量细胞停滞在G₂/M 期, 凋亡细胞增多。结论:Evo 选择性的抑制肿瘤细胞的生长, 引起SPCA 1细胞典型的凋亡形态学改变并使细胞停滞于G₂/M 期, 其机制可能与诱导细胞凋亡和周期阻滞有关。     

Hepatic autophagy and mitophagy status in dairy cows with subclinical and clinical ketosis

Severe negative energy balance around parturition is an important contributor to ketosis, a metabolic disorder that occurs most frequently in the peripartal period. Autophagy and mitophagy are important processes responsible for breaking down useless or toxic cellular material, and in particular damaged mitochondria. However, the role of autophagy and mitophagy during the occurrence and development of ketosis is unclear. The objective of this study was to investigate autophagy and mitophagy in the livers of cows with subclinical ketosis (SCK) and clinical ketosis (CK). We assessed autophagy by measuring the protein abundance of microtubule-associated protein 1 light chain 3-II (LC3-II; encoded by MAP1LC3) and sequestosome-1 (p62, encoded by SQSTM1), as well as the mRNA abundance of autophagy-related genes 5 (ATG5), 7 (ATG7), and 12 (ATG12), beclin1 (BECN1), and phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3). Mitophagy was evaluated by measuring the protein abundance of the mitophagy upstream regulators PTEN-induced putative kinase 1 (PINK1) and Parkin. Liver and blood samples were collected from healthy cows [n = 15; blood β-hydroxybutyrate (BHB) concentration <1.2 mM], cows with SCK (n = 15; blood BHB concentration 1.2 to 3.0 mM) and cows with CK (n = 15; blood BHB concentration >3.0 mM with clinical signs) with similar lactation numbers (median = 3, range = 2 to 4) and days in milk (median = 6, range = 3 to 9). The serum activity of aspartate aminotransferase and alanine aminotransferase was greater in cows with CK than in healthy cows. Levels of oxidative stress biomarkers malondialdehyde and hydrogen peroxide were also higher in liver tissue from ketotic cows (SCK and CK) than from healthy cows. Compared with cows with CK and healthy cows, the hepatic mRNA abundance of MAP1LC3, SQSTM1, ATG5, ATG7, ATG12, and PIK3C3 was upregulated in cows with SCK. Compared with healthy cows, cows with SCK had a lower abundance of p62 and a greater abundance of LC3-II, but levels of both were higher in cows with CK. The mRNA abundance of ATG12 was lower in cows with CK than in healthy cows. Furthermore, the hepatic protein abundance of PINK1 and Parkin was greater in cows with SCK and slightly lower in cows with CK than in healthy cows. These data demonstrated differences in the hepatic activities of autophagy and mitophagy in cows with SCK compared with cows with CK. Although the precise mechanisms for these differences could not be discerned, autophagy and mitophagy seem to be involved in ketosis.     

红光理疗对改善鼻中隔成形术后黏膜缺血的疗效观察

目的：观察红光理疗对改善鼻中隔成形术后鼻中隔黏膜局部缺血状态的疗效。方法：对30例行鼻中隔成形术,术后发现鼻中隔黏膜局部缺血的患者,将其随机分成两组,一组为红光理疗组即实验组,另一组为常规治疗组即对照组。实验组每日先行鼻部红光理疗15分钟,然后以浸有重组人表皮生长因子及金霉素软骨的明胶海绵贴敷于鼻中隔缺血处黏膜;对照组...     

二氧化氯在消毒方面的特性及其应用性

首先介绍了二氧化氯的基本性质,然后具体分析了其在消毒方面所具有的特点和优势,最后对其应用前景进行了展望。