氩离子凝固术对猪食管黏膜凝固作用的实验观察

目的:探讨内镜下氩离子凝固术(argon plasma coagulation, APC)的疗效及安全性. 方法:用APC分别对20只新鲜猪的食管黏膜以不同的输出功率(40 W,60 W,80 W)及不同的作用时间(2 s,4 s, 6 s)进行凝固,超声内镜(endoscopic ultrasonography,EUS) 观察黏膜凝固深度. 结果:在功率60 W,时间为2 s及4 s时,侵犯到深黏膜层分另4为18例(18/20,90%)和17例(17/20,85%),无1 例侵犯到肌层. 只要限定一定的功率和时间,APC为一种安全有效的内镜下治疗食管疾病的方法.

茶色素胶囊对血液流变学及凝固性作用的临床观察

用茶色素治疗２８９例心血管病患者，观察茶色素对血液流变学及凝固性的作用，结果发现茶色素可降低全血、血浆粘度及最大血小板聚集率。测定了１２１例的凝血酶时间、凝血酶原时间及白陶土部分凝血活酶时间，治疗前后结果对比，Ｐ＞０．０５，无统计意义。

β-榄香烯抗凝血作用及不同剂量阿司匹林的影响

目的:研究β-榄香烯的抗凝血作用及不同剂量阿司匹林的影响。方法:随机将80只小鼠随机分为8组。空白组,β-榄香烯小剂量组、中剂量组、大剂量组,阿斯匹林小剂量组、大剂量组,β-榄香烯中剂量+阿司匹林小剂量组,β-榄香烯中剂量+阿司匹林大剂量组。给药10天后,眼眶静脉丛采血观察记录凝血时间;并各组小鼠开腹观察胃肠道出血点。结果:β-榄香烯可延长凝血时间,可致小鼠胃肠道出血,且与剂量呈正相关。大剂量阿司匹林可拮抗β-榄香烯的上述作用。结论:β-榄香烯可有效延长凝血时间,并可引起出血,具有一定的抗凝血作用,大剂量阿司匹林可抑制其出血反应。

面部雀斑行化学剥脱术术后并发症的观察及护理

面部化学剥脱术是通过利用化学药物的细胞毒性以及蛋白凝固作用造成表皮细胞破坏,蛋白质凝固溶解,引起皮肤炎症,继而利用创伤修复的过程促进表皮细胞分裂,使胶原纤维排列规则化、均一化,同时还能够使变性的弹力纤维发生质的改变,减少皮肤皱纹,还可以抑制过多的皮脂分泌,改善毛孔阻塞，淡化色素沉着斑，最终达到改善皮肤质地，美容皮肤的目地。我科于是1986年始，运用苯酚化学剥脱术治疗面部雀斑取得了较好的美容效果，

主要溶血栓化合物的特性与新型溶血栓化合物的探索

溶血栓化合物在治疗血栓性疾病中具有极为重要的地位和作用。本文首先简要归纳了血栓的形成过程及血栓（纤维蛋白）的溶解途径，接着从两个方面介绍了溶血栓化合物的概况，一是传统溶血栓化合物的特性，如尿激酶、组织型纤维蛋白溶酶原激活剂、孟替普酶等；二是新型溶血栓化合物的特性及其研究进展，如纳豆激酶、毛虫毒V、葡萄糖甘油二酯等。最后展望了溶血栓化合物的发展前景。

脱乙酰的甲壳素衍生物——羧甲基壳聚糖的不良反应

甲壳素（chitin）经高浓度强碱、高温处理后会有部分N-乙酰基脱落，又称为壳聚糖或几丁糖（chi—tosan）。按脱乙酰程度的不同，β-（1—4）-linked—D—glucosamine（脱乙酰）和N—aeetyl—D—glucosamine（乙酰化）两种结构单体的随机组成比例不同。随脱乙酰比例的增高而出现凝血与凝固蛋白质的作用。近年来美国政府批准脱乙酰甲壳素用于创可贴和其他试剂。马里兰大学的研究成果用螃蟹、虾外壳纤维制取的脱乙酰的甲壳素具有很强的止血功能，将其用于战伤瞬间止血。高脱乙酰的甲壳素具强碱性．对蛋白质的凝固作用，

大蒜粗提物对小鼠凝血时间的影响

目的:比较紫皮、白皮大蒜粗提物不同剂量、不同给药途径对小鼠凝血时间的影响,为临床合理用药提供实验依据。方法:采用毛细玻管法测定小鼠凝血时间。结果:灌服高剂量紫皮、白皮大蒜粗提物对小鼠凝血时间有明显的延长作用(P<0.01);中剂量有延长作用(P<0.05);小剂量和对照药无显著影响(P>0.05);腹腔注射高、中、低3个剂量紫皮、白皮大蒜粗提物和对照药对小鼠凝血时间均有明显的延长作用(P<0.01)。结论:大蒜粗提物对小鼠凝血时间有明显的延长作用。腹腔注射作用强于灌胃,且随着浓度的加大作用增强;相同浓度和给药途径的紫皮、白皮大蒜对小鼠凝血时间的影响无显著差异。

As-cast microstructure of Mg-Al-Zn magnesium alloys

The research achievements on as-cast microstructure in Mg-Al-Zn alloy were summarized. Under permanent mould cast condition, there are four kinds of primary compounds with distinct crystallographic morphology, Mg17Al12(γ),Mg32(Al,Zn)49 (τ), MgZn (ε) and a ternary icosahedral quasi-crystalline compound (Q). Accordingly, Mg-Al-Zn alloy can be grouped intoγ-,τ-,ε- and Q-rype alloy by each characteristic compound. The volume fraction ofγ-Mg17Al12 in commercialγ-type alloy increases with increasing Al content. MgZn and MgxAlyZnz ternary complex compounds emerge with the change of the element content Al and Zn and Zn/Al concentration ratio. A practical phase diagram showing microstructure constituent change with composition was proposed. The addition of micro-alloying elements Y and Sr results in not only obvious refinement of eutectic cluster but also eutectic morphological change from block to granule.

Crystal preferential orientation of Al-1.0%Si alloy in continuous unidirectional solidification process

Al-1.0%Si alloy rods containing unidirectional microstructures were fabricated by continuous unidirectional solidification (CUS) process. The crystal growth orientation evolution of Al-1.0%Si alloy in CUS process was studied. The microstructure was observed and the orientation results examined by electron back scattering diffraction(EBSD) indicate that at the beginning of CUS process the crystals grow along a certain preferred orientation, <100> direction, but there are also other growth directions deflecting from this preferred orientation. It is found that as directional solidification continues, the crystals with high growth speed remain and those with low growth speed vanish. The crystal preferred orientation tends to be <100> direction in competition growth process. Namely, the <100> fiber texture of Al-1.0%Si alloy rod becomes stronger in the stable directional solidification establishing process. When the solidification parameters remain stable, the crystal growth orientation also obtains in steady state. Once the technological parameters fluctuate, the stray crystals deviating from the preferred orientation appear. After the process of competition growth the crystals regain strong preferred orientation. The orientation distribution function(ODF) results also testify the above conclusions.

Effect of vacuum on solidification process and microstructure of LFC magnesium alloy

Lost foam casting (LFC) is regarded as a cost-effective, environment-friendly vital option to the conventional casting process for production of near-net shape castings with high quality. Effect of vacuum on the solidification process and microstructure of LFC magnesium alloy were explored. The results indicate that vacuum plays a very important role in the heat transfer during mould filling and solidification periods, it increases the cooling rate of the filling melt, but greatly decreases the cooling rate of the casting during solidification period, and the solidification time of the casting is greater than that without vacuum. The microstructure of LFC magnesium alloy is rather coarse. Compared with that without vacuum, the microstructure of the LFC magnesium alloy under vacuum is more refined and has less precipitatedβ-phase, which is formed at the grain boundry and around the Al-Mn compound particle.

Solidification and remelting of Al through Al_2O_3 fibrous preform under centrifugal force

The solidification and remelting of molten aluminum through a porous preform under centrifugal force field were modeled numerically. The results show that the transient solidification and remelting phenomena appear on the infiltration front and can be divided into two distinct regions: the remelting region and solid-liquid congruent melting region. The decrease of porosity always results in the increase of moving velocity difference between the infiltration front and the remelting front, which leads to the increase of the solid-liquid congruent region extent. But for the decrease of the rotational frequency, the difference of moving velocity between infiltration front and remelting front decreases, which leads to the decrease of regional extent. The infiltration front moving velocity is mainly influenced by the centrifugal infiltration pressure, whereas the remelting front moving velocity is mainly influenced by the material thermodynamics. The transient solidification and remelting phenomena are the intercoupling results between the centrifugal infiltration dynamics and the material thermodynamics.

Competitive growth of high purity aluminum grains in directional solidification

A self-made directional solidification setup was used to prepare high purity aluminum ingots of 100mm in diameter. The morphology of the growth interface was detected by SEM and AFM, and the grain lattice orientation was detected by XRD. The results indicate that the grains suffer competitive growth under any conditions in experiments. The lattice orientation of the preferred grains is determined by the flow field above the solid-liquid interface. The horizontal lattice position does not change during the growth process. However, the lattice orientation in the growth direction varies with the growth velocity and approaches to [100] gradually during the growth process.

Solidification microstructures and mechanism of grain refinement of electrolytic low titanium Al alloys

The solidification microstructures and the mechanism of grain refinement of electrolytic low titanium Al alloys were investigated by means of the wedge-shaped sample, the directional solidification and the rapid solidification ribbon. The results show that the coarse columnar grains formed in pure Al are transformed into the equiaxed grains in electrolytic low titanium Al alloys. The grain refinement is resulted from the constitutional supercooling caused by Ti and heterogeneous nucleation of Al3Ti particles. Under the condition of normal cooling rate, the grains are refined by the increment of constitutional supercooling when the content of titanium is less than 0.2%. With the increment of content of titanium, the grains are mainly refined by heterogeneous nucleation of Al3Ti particles. The grain size is decreased with the increment of cooling rate. When the cooling rate is larger than 105℃/s, the grain size is decreased to 0.1-10μm, the grain refinement is resulted from the larger cooling velocities mainly. After directional solidification, the equiaxed grains can be formed and the Ti element is distributed at the center of the grains.

不得随意“同居”的物品

不管是食品还是用品,由于它们的内在属性不同,在存放时是有一定讲究的。因而提醒您务必注意:新鲜水果与纯碱接触,易发热腐烂;粮食与水果共放,粮食易发热,水果受热后变得干瘪。

95%和75%的酒精,哪种消毒效果好

首先我们要搞清楚,酒精之所以能杀菌消毒,主要是因为酒精能引起蛋白质变性,导致细菌或是病毒的死亡。许多人以为,酒精浓度越高,消毒效果越好,其实这是错误的。高浓度酒精(所谓的95%酒精)能将细菌表面的蛋白质迅速凝固,但是也仅止于外层;对于一些细菌来说,它的内部仍是活性的,所以杀了等于没杀。经过研究证实,75%的酒精,可以兼具蛋白质凝固作用及穿透效果,达到彻底的杀菌功能。75%的酒精适用于消毒完整没有伤口的皮肤,

哪些东西不易存放在一起

一、鲜蛋与生姜、洋葱放在一起,姜、葱的强烈气味钻入蛋壳小气孔,会加速鲜蛋变质,时间稍长,蛋就会发臭。二、棉花与酸类物品存放,纤维易脆断。三、橡胶制品与油接触会失去弹性。四、尼龙制品与樟脑同放,纤维坚固度会大大降低。

有关饮食安全的冷知识

冷知识不知不觉地出现在大众的视野中,比如“细口杯子脏了用碎鸡蛋壳加温水,用力摇晃可清洗干净”“蛋清中有部分成分有凝固作用,有少量出血时可以在纱布上涂抹蛋清敷在伤口上”等等。有很多冷知识确实是我们需要了解的,和我们日常生活切实相关的则是有关食品安全的冷知识,在有着悠久饮食文化的中国,在吃上尤为的注重,但是这些你是否了解?