微/纳米结构含锌硅酸钙基涂层成骨性能研究

骨科植入物涂层的表面形貌和化学组成对炎症反应的进程和骨形成的发生都发挥着重要调节作用。为综合利用微/纳米仿生结构和生物活性元素的优势,将含锌(Zn)的纳米结构物质引入到经水热处理后的等离子喷涂硅酸钙(calcium silicate, CS)涂层表面,对所制备涂层的物相组成、表面和截面形貌、比表面积、Zeta电位和生理环境下离子溶出等物理化学性能进行了表征。相比于常规CS涂层,具有微/纳米复合结构的CS和含锌CS涂层拥有更高比表面积和孔容,可吸附更多血清蛋白和纤维连接蛋白,通过刺激细胞内整合素以及下游vinculin和FAK基因表达,提高了骨髓间充质干细胞(BMSCs)铺展能力。涂层中锌的引入进一步提高了其表面BMSCs的增殖能力和与成骨细胞分化相关的基因表达。具有微/纳米复合结构的涂层明显上调了RAW264.7巨噬细胞中M2表型因子(CD206和ARG)基因表达,而涂层中溶出的Zn²⁺显著提高了RAW264.7细胞中抑炎症因子(IL-1ra和IL-10)基因表达,促使其向抑炎症表型转化。骨科植入物涂层表面锌元素和纳米结构的引入有利于创建良好的骨免疫微环境,促进骨...     

Hypocalcemia—Cow-level prevalence and preventive strategies in German dairy herds

Hypocalcemia around calving is considered a gateway disease that can lead to health disorders and decreased milk production. The objective of this cross-sectional study was to evaluate the prevalence of clinical and subclinical hypocalcemia 0 to 48 h after calving. Blood samples were drawn from 12 animals of each dairy farm (n = 115) and analyzed for serum calcium, magnesium, and phosphorus concentration. Cows not affected clinically but with a serum calcium concentration below 2.0 mmol/L were characterized as subclinical hypocalcemic animals. Recumbent cows with a serum calcium concentration below 2.0 mmol/L were defined as cows suffering from clinical milk fever. Herds were classified into negative (0 to 2/12), borderline (3 to 5/12), and positive (≥6/12) according to the number of animals with hypocalcemia. Strategies to control hypocalcemia were documented. Prevalence of clinical milk fever was 1.4, 5.7, and 16.1% for second, third, and ≥fourth parity cows, respectively. None of the cows in first lactation were suffering from clinical milk fever. Based on the threshold of 2.0 mmol/L, 5.7, 29.0, 49.4, and 60.4% of cows in first, second, third, and ≥fourth lactation were suffering from subclinical hypocalcemia, respectively. Fourteen, 51, and 50 herds were classified as negative, borderline, and positive, respectively. A positive association was observed between serum calcium and serum phosphorus concentration. Serum calcium and magnesium concentration were negatively associated. Only 50 of 115 farms had a control strategy implemented to avoid hypocalcemia. Most common was the use of oral calcium products (40/115 herds), followed by feeding of anionic salts in the close-up diet (10/115 herds). These results indicate that the prevalence of clinical and subclinical hypocalcemia in German dairy herds was high and that an active control strategy was not implemented on all farms. The negative association between calcium and magnesium warrants further research regarding the physiological regulation of these 2 minerals around parturition.     

流化床脱水制无水氯化镁工艺研究

水氯镁石(六水氯化镁)脱水制无水氯化镁是盐湖镁资源利用的关键环节,复盐法是水氯镁石脱水的重要方法,由复盐合成、造粒及流态化热分解等步骤组成。采用热分析技术(TG-DTG)研究了复盐热解过程。结果显示,复盐热解主要分为两个阶段:第一个阶段脱去六个结晶水;第二个阶段脱去盐酸苯胺助剂,热重结果为后续实验提供理论依据。实验首先通过均匀液滴喷射技术(振动造粒)制备得到六水氯化镁-盐酸苯胺复盐颗粒。然后在流化床中进行复盐热分解脱水、脱助剂得到无水氯化镁。通过实验探索得到水氯镁石复盐流态化热分解的最佳工艺参数:脱水氮气流量1.6 m3/h～1.8 m3/h、脱盐酸苯胺氮气流量1.0 m3/h～1.2m3/h、脱水温度300℃、脱水时间0.5 h、脱盐酸苯胺温度350℃、脱盐酸苯胺时间1 h。     

卷烟纸参数对卷烟持灰能力的影响

为了探究吸燃条件下卷烟纸对持灰能力的影响,以定量、透气度、碳酸镁添加量、助燃剂之钠钾比、酸根类型和助燃剂用量为参数,采用均匀试验设计方法设计、制备了12种不同卷烟纸参数组合的卷烟样品,通过单因素分析、回归分析等方法研究了卷烟纸参数对卷烟持灰能力的影响,并进行了卷烟纸参数优化.结果表明:① 随着卷烟纸参数组合的变化持灰能...     

响应面法优化罗非鱼鱼皮胶原多肽螯合镁的工艺条件的研究

以罗非鱼鱼皮为原料,研究鱼皮胶原多肽和镁离子的螯合工艺条件。探讨了鱼皮胶原多肽与氯化镁的质量比、反应体系的pH、螯合温度、螯合时间等因素对鱼皮胶原蛋白螯合反应的影响;在单因素实验的基础上,通过响应面法对鱼皮胶原多肽与镁的螯合工艺条件进行优化,确定最佳的螯合工艺条件为:质量比1∶5、pH7.0、螯合温度70℃、螯合时间30min。在此条件下,螯合率达84.58%。通过对比螯合反应前后傅里叶变换红外光谱图的变化,证明了鱼皮胶原多肽与镁离子形成了新的螯合物。      

木耳增重掺假判别方法研究

目的建立木耳增重掺假的综合判定方法。方法木耳掺假主要是采用掺入氯化镁、硫酸镁等镁盐增加重量谋取暴利,因此,可以通过检测木耳中镁的含量、分含量、吸水性等指标来推测木耳中是否添加了镁盐。结果木耳中镁的本底值在2500 mg/kg以下,木耳灰分、吸水性的本底值分别小于6%和大于6 mL/g。结论通过考察木耳中镁含量、灰分值、吸水性的基底值,以帮助判断木耳样品中是否被人为添加镁盐。该方法对判别木耳增重掺假是可信的方法。     

铁离子强化镁盐清净赤砂糖回溶糖浆工艺

以赤砂糖回溶糖浆为研究对象,以脱色率、除浊率以及絮凝物体积为指标,通过单因素试验考察了铁离子浓度、反应温度、时间以及pH对赤砂糖回溶糖浆的清净效果;在单因素试验的基础上,采用正交试验对工艺条件进行优化,在镁离子质量浓度为100 mg/L的条件下,铁离子强化镁盐清净赤砂糖回溶糖浆的最佳工艺条件为:铁离子质量浓度为250 mg/L、反应温度60℃、时间20 min、pH 11.3。在此条件下,回溶糖浆的脱色率可达90.62%,除浊率为76.28%,絮凝物体积为17 mL。单纯使用100 mg/L的镁离子对回溶糖浆进行处理,脱色率为64.23%,除浊率为59.49%,絮凝物体积为37 mL。结果显示:铁离子对镁离子清净赤砂糖回溶糖浆具有显著的强化作用。     

高分散性白炭黑生产新工艺探究

以液体水玻璃和稀硫酸为主要原料,在反应过程中通过添加可溶性铝盐如:硫酸铝、铝酸钠等来提高产品的分散性,改变了添加反应母液的传统方式。将配制好的水玻璃溶液、稀硫酸、铝酸钠溶液以一定的温度、浓度、流速、流量在反应器中反应,然后酸化、洗涤、干燥得到高分散白炭黑成品。     

ICP-OES法和离子色谱法测定水中钙、镁比对研究

目的:对ICP-OES法和离子色谱法测定水中钙、镁两种元素方法进行比对研究。方法:分别采用ICP-OES法和离子色谱法对不同水源10个水样进行比对测定。结果:两种方法灵敏度、准确度、精密度相当,但ICP-OES分析速度较离子色谱提高10倍。结论:ICP-OES法和离子色谱法均适用于水样中微量、常量钙、镁含量的测定,但ICP-OES法分析速度快,且具有多元素同测的特点,更适合于批量样品分析。