Compressive Properties and Energy Absorption Characteristics of Extruded Mg-Al-Ca-Mn Alloy at Various High Strain Rates

This paper is focused on the mechanical properties and the energy absorption characteristics of the extruded Mg-Al-Ca-Mn alloy in different compression directions under high strain rate compression. Compressive characterization of the alloy was conducted from the high strain rate (HSR) test by using a Split Hopkinson Pressure Bar (SHPB). Results show that the investigated alloy exhibits a strong strain rate sensitivity. With the rise of strain rate, the compressive strength is increased significantly, and the deformation ability also improves. When compressed along the extrusion direction, as the strain rate increases, the total absorbed energy E, the crush force efficiency (CFE), and the specific energy absorption SEA of Mg-Al-Ca-Mn alloy are all greatly improved as compared with those obtained along other compression directions.     

MEMBRANE Na &#180 +;-K &#180 +; ATPase MEDIATED CASCADE IN BIPOLAR MOOD DISORDER,MAJOR DEPRESSIVE DISORDER,AND SCHIZOPHRENIA RELATIONSHIP TO HEMISPHERIC DOMINANCE

The isoprenoid pathway produces digoxin, an endogenous membrane Na &#180 +;-K &#180 +; ATPase inhibitor and regulator of neurotransmitter transport. The objective of the study was to relate digoxin status and hemispheric dominance to the pathogenesis of psychiatric disorders--bipolar mood disorder, major depressive disorder, and schizophrenia. The following parameters were assessed in bipolar mood disorder during the manic phase and depressive phase of the illness as well as in major depressive disorder, and schizophrenia: HMG CoA reductase activity, tryptophan and tyrosine catabolic patterns, red blood cell (RBC) Na &#180 +;-K &#180 +; ATPase activity, and serum magnesium. These parameters were compared to individuals of dif fering hemispheric dominance. The levels of serum digoxin and HMG CoA reductase activity were found to be decreased in the depressive phase of bipolar mood disorder and major depressive disorder with a cor responding increase in RBC Na &#180 +;-K &#180 +; ATPase activity and serum magnesium levels. There was increase in tyrosine and tyrosine catabolites, and a reduction in tryptophan and its catabolites, in the serum in the depressive phase of bipolar mood disorder and major depressive disorder. The neurotransmitter patterns and digoxin levels in the depressive phase of bipolar mood disorder/major depressive disorder correlated with those in right-handed/left hemisphere dominant individual. The neuro transmitter patterns and digoxin levels in the manic phase of bipolar mood disorder and schizophrenia correlated with those in left-handed/right hemisphere dominant individuals. Digoxin status and hemispheric domi nance could correlate with the pathogenesis of psychiatric disorders--schizophrenia, major depressive disorder, and bipolar mood disorder.     

形状记忆合金弓齿钉治疗腕舟状骨腰部骨折

正2013年10月~2015年3月,我科采用腕掌侧切开复位形状记忆合金弓齿钉治疗17例腕舟状骨腰部骨折患者,疗效满意,报道如下。1材料与方法1.1病例资料本组17例,男15例,女2例,年龄16~42岁。左侧1例,右侧16例,均为闭合骨折。新鲜骨折16例,陈旧性骨折1例,合并桡骨茎突骨折1例。1.2治疗方法臂丛麻醉下手术。取     

Relaxant effects of metoclopramide and magnesium sulfate on isolated pregnant myometrium: an in vitro study

BackgroundMetoclopramide and magnesium sulfate are extensively used agents in obstetrics. In this study, the relaxant properties of metoclopramide and magnesium sulfate on pregnant myometrium, together with the possible reversing influences of oxytocin and cabergoline (a dopamine D₂ receptor agonist), were investigated.MethodsMyometrial strips from 24 parturients were randomly allocated to four groups: control (Group CON), magnesium sulfate and oxytocin (Group MSO), metoclopramide and oxytocin (Group MEO), and metoclopramide and cabergoline (Group MEC). Myometrial strips were mounted on a myograph bathed in Krebs buffer. Saline (Group CON) and five incremental doses of magnesium sulfate (Group MSO) or metoclopramide (Groups MEO and MEC) were sequentially microinjected into the bath. Subsequently, oxytocin (Groups CON, MSO and MEO) or cabergoline (Group MEC) was microinjected into the bath. The myometrial contractile characteristics after each drug injection, including contractile force, interval and duration, were analyzed.ResultsMagnesium sulfate was more potent for prolonging myometrial contractile interval than reducing contractile force. Metoclopramide relaxed myometrial contractions by inhibiting contractile force and prolonging contractile interval in a concentration-dependent manner. Oxytocin reversed both the inhibited contractile force and the prolonged contractile interval caused by a high concentration of magnesium sulfate but accelerated the contractile interval and had no significant effect on the contractile force suppressed by metoclopramide. The relaxant effects of metoclopramide were completely reversed by cabergoline.ConclusionsBoth magnesium sulfate and metoclopramide relaxed myometrial contractions, and exhibited different responses to subsequent oxytocin treatment. The relaxant mechanism of metoclopramide may be via blockade of dopamine D₂ receptor, which requires further investigation.     

硫酸镁联合银杏达莫治疗慢性肺源性心脏病的疗效观察

目的探讨硫酸镁联合银杏达莫治疗慢性肺源性心脏病的疗效。方法将笔者所在医院2011年3月～2012年3月72例慢性肺源性心脏病患者随机分成对照组和治疗组,对照组患者进行常规的抗感染、保持呼吸道通畅、利尿、扩张血管、纠正电解质平衡等治疗;治疗组在对照组的基础上加用硫酸镁和银杏达莫。观察两组患者治疗前后心功能、肺动脉收缩压的改善情况,并进行临床观察分析。结果治疗组的总有效率明显高于对照组,差异有统计学意义(P<0.05)。结论硫酸镁联合银杏达莫治疗慢性肺源性心脏病疗效显著,临床上建议进一步推广运用。     

Plasma Peroxyl Radical-Trapping Capacity in Severe Preeclampsia is Strongly Related to Uric Acid

The total peroxyl radical-trapping antioxidant parameter (TRAP) of plasma from nine patients suffering from severe preeclampsia was compared with that from nine control patients sharing the same weeks of pregnancy. Measurement of TRAP was by a new chemiluminescent method. The mean TRAP in preeclamptic patients was 1288 ± 110 µmol/l and in control patients 970 ± 153 µmol/l (p<0.001). TRAP was highly correlated with plasma uric acid (r=0.86), and 91% of the increase in TRAP was due to increase in uric acid, which raises a question of the possible antioxidative role of uric acid in preeclampsia.     

Local release of magnesium from mesoporous TiO2 coatings stimulates the peri-implant expression of osteogenic markers and improves osteoconductivity in vivo

Local release of Mg ions from titanium implant surfaces has been shown to enhance implant retention and integration. To clarify the biological events that lead to this positive outcome, threaded implants coated with mesoporous TiO₂ thin films were loaded with Mg-ions and placed in the tibia of rabbits for 3 weeks, after surface characterization. Non-loaded mesoporous coated implants were used as controls. Peri-implant gene expression of a set of osteogenic and inflammatory assays was quantified by means of real-time quantitative polymerase chain reaction. The expression of three osteogenic markers (OC, RUNX-2 and IGF-1) was significantly more pronounced in the test specimens, suggesting that the release of Mg ions directly at the implant sites may stimulate an osteogenic environment. Furthermore, bone healing around implants was evaluated on histological slides and by diffraction-enhanced imaging (DEI), using synchrotron radiation. The histological analysis demonstrated new bone formation around all implants, without negative responses, with a significant increase in the number of threads filled with new bone for test surfaces. DEI analysis attested the high mineral content of the newly formed bone. Improved surface osteoconductivity and increased expression of genes involved in the bone regeneration were found for magnesium-incorporation of mesoporous TiO₂ coatings.     

硫酸镁联合尼莫地平治疗弥漫性轴索损伤的临床分析

目的 研究弥漫性轴索损伤(DAI)患者的血清镁离子浓度以及联合尼莫地平早期给予镁离子治疗对其预后的影响. 方法 将南方医科大学珠江医院神经外科自2006年9月至2010年6月收治的99例DAI患者按随机数字表法分为2组,入院时均检测血清镁离子浓度,均予尼莫地平持续静脉注射,连续使用1周.另治疗组给予250g/L硫酸镁静脉滴注,连续使用3d;对照组不使用硫酸镁.结合随访情况,分析患者预后与入院时镁离子浓度及与硫酸镁治疗的关系. 结果 2组患者间病死率比较差异无统计学意义(P＜0.05),治疗组恢复良好率及轻残率均明显高于对照组,差异有统计学意义(P＜0.05).2组患者入院时血清镁离子浓度均对格拉斯哥预后分级评分(GOS)无明显影响. 结论 入院时血清镁离子水平不能影响患者的预后.对比单独使用尼莫地平,伤后早期联合应用250 g/L硫酸镁持续静脉滴注,虽不能有效降低患者死亡率,但可降低重残率,改善患者的预后和生存质量.     

Essential elements in depression and anxiety. Part I

Essential elements are very important for the proper functioning of the human body. They are required for fundamental life processes such as cell division and differentiation and protein synthesis. Thus a deficiency of these essential elements is associated with an enormous health risk that can ultimately lead to death. In recent years, studies have provided valuable information on the involvement of essential elements in psychiatric disorders, in particular depression and anxiety.There is strong evidence indicating that deficiency of essential elements can lead to the development of depressive and/or anxiogenic behaviour and supplementation can enhance therapeutic effect of antidepressants and anxiolytics. This review presents the most important results from preclinical and clinical studies showing involvement of essential elements such as zinc, magnesium, lithium, iron, calcium and chromium in depression and anxiety. From these studies it is evident that different types of depression and anxiety respond to treatment at different receptors indicating that the underlying mechanisms are slightly different. Furthermore, administration of low dose antidepressants supplemented with an element is effective and can reduce unwanted side effects in different types of depression/anxiety.