共沉法制备锰锌软磁铁氧体微粉钙镁脱除实验

研究了在碳酸盐共沉淀法制备锰锌软磁铁氧体前躯体净化过程中NH4F对钙镁杂质深度脱除的影响.实验结果表明,NH4F用量、反应时间和温度、pH值对钙镁的深度脱除都有显著影响.在反应温度为90 ℃,加入的NH4F溶液质量浓度为370.4 g·L^-1、体积分数为2.4×10^-2,pH值控制为3.5,反应时间为1 h的条件下,净化后液中的钙镁质量浓度分别为0.003,0.019 g·L^-1,共沉粉中的钙镁质量分数分别为7.5×10^-5和5．6×10^-5,均小于10^-4,达到制备高档锰锌软磁铁氧体产品的要求.     

钙通道抑制剂对川百合花粉萌发的影响

细胞内钙离子在花粉萌发过程中发挥重要作用,钙离子如何被植物花粉细胞所吸收是植物生殖生理研究的热点问题．对一些常用的钙通道抑制剂对川百合花粉萌发和花粉管伸长生长的影响进行了研究．结果表明,萌发中的花粉需要从外界吸收大量钙离子,电压依赖型钙通道的有机抑制剂(异搏定、尼群地平、地而流卓)和3价无机离子(镧、铝、钆)可以明显抑制花粉萌发,电压依赖型通道很可能是细胞外钙离子进入萌发花粉的重要途径．     

香菇膳食纤维中Ca~(2+)在胃肠酸度下的溶出特性

研究了香菇膳食纤维中钙在胃酸和肠道酸度下的溶出特性, 发现采用冷中性洗涤剂法从香菇柄中制取的香菇膳食纤维, 在胃酸条件下随ｐＨ值的降低溶出的钙增多, 最低值为０．０５１ ｍ ｇ／ｇ、最高值为０．０９２ ｍ ｇ／ｇ; 在肠道酸度下则随ｐＨ值的降低溶出的钙减少, 最低值为０．０８２ ｍ ｇ／ｇ、最高值为０．１５５ ｍ ｇ／ｇ, 钙在肠道酸度下的溶出显然受钠离子的影响． 钙在两条件下的溶出均在１５ｍ ｉｎ 内达到平衡．     

Effects of nitrogen ion implantation on Ca2+ concentration and membrane potential of pollen cell

The effects of low energy nitrogen ion implantation on Ca²⁺ concentration and membrane potential of lily (lilium davidii Duch) pollen cell have been studied. The results showed that the Ca²⁺ concentration was increased when pollen grain was implanted by nitrogen ion with energy 100 keV and dose 10¹³ ions/cm². However, the increase of Ca²⁺ concentration was partly inhibited by the addition of Ca²⁺ channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased, but the effect decreased by adding Ca²⁺ channel inhibitor. However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intracellular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.     

Regulation of the arachidonic acid-stimulated respiratory burst in neutrophils by intracellular and extracellular calcium

The respiratory burst is an important physiological function of the neutrophils in killing the bacteria invading in human body. We used chemiluminescence method to measure the exogenous arachidonic acid-stimulated respiratory burst, and measured the cytosolic free calcium concentration in neutrophils by the fluorescence method. It was found that, on one hand, the arachidonic acid-stimulated respiratory burst was enhanced by elevating the cytosolic free calcium concentration in neutrophils with a potent endomembrane Ca2+-ATPase inhibitor, Thapsgargin; on the other hand, chelating the intracellular or extracellular calcium by EGTA or BAPTA inhibited the respiratory burst. Results showed that calcium plays an important regulatory role in the signaling pathway involved in the exogenous arachidonic acid-stimulated respiratory burst of neutrophils.     

Glucose-induced Ca2+ signals in rat pancreatic β cells

Using microfluorometry to assay intracellular Ca2+ , the influences of varied factors on glucose induced Ca22+ signals, such as glucose-induced initial decline phase (GIDP), Ca2+ oscillation, and Ca2+ release from internal stores, were investigated in single rat pancreatic β cells. Glucose was able to evoke GIDP even at non-stimulus concentration (5 mol/L), which is insufficient to induce Ca2+ spikes. GIDP was dependent on neither membrane depo larization nor extraeellular Ca2+ . However, GIDP was inhibited by thapsigargin, indicating a dependence on Ca2+ up take by Ca22+ stores. The glucose-induced calcium oscillation was inhibited when external Ca2+ was removed. However, thapsigargin could not block the Ca2+ oscillation. These results suggest that maintenance of Ca22+ oscillation requires ex tracellular Ca2+ but not Ca2+ stores. Glucose was able to evoke Ca2+ signals even in the absence of external Ca2+ . The glucose-induced Ca2+ release from intracellular Ca2+ stores was blocked by TTX. However, TTX had no effect on high K--induced Ca2+ store release, suggesting that membrane depolarization can directly release Ca2+ from some internal Ca2+ stores in β cells.     

钙离子注入钛表面及其微观分析

目的研究改性后钛表面的结构和化学组成.方法以1×10     

淤浆法制备的羧甲基纤维素钙素片的崩解性

采用淤浆法新工艺制备了药剂辅料用羧甲基纤维素钙（Ca-CMC),并与常用崩解剂,根据其方法制备的Ca-CMC进行了比较,添加淤浆法制备的羧甲基纤维素钙的素片崩解速度最快,且产物中无钙化剂残留,其它技术指标达到药剂辅料要求,文中还对制备过程中Ca^2 不能完全取代Na^ 的原因做了分析。     

市售补钙制剂钙含量的测定

鉴于目前许多补钙制剂尚未收入国家药典,国家尚未提出测定补钙制剂中钙含量的统一方法,研究了以酸性铬蓝K为显色剂,在pH值为10.5的四硼酸钠缓冲溶液中与Ca2+络合,用分光光度法测定多种市售补钙制剂的钙含量;研究了钙-酸性铬蓝K络合物的最佳形成条件:λ=498nm,pH=10.5,显色剂用量为2mL,缓冲溶液用量为0.5mL,钙浓度在0～2.4×10-5mol/L范围内遵循朗伯-比尔定律,相对标准偏差为1.2%。     

腎钙乳沉积症(附1例报告及文献复习)

本文报告1例罕见的肾钙乳沉积症,本症是肾盂源性囊肿内有钙乳沉积,分为两类;第一类,钙乳沉积于扩大的肾盂源性囊肿内,肾功能正常,占多数;第二类,有明显的肾积水和肾盏扩张,合并多发性钙乳沉积,肾功能差,属少数。病理检查,肾囊肿囊壁有肾单位存在,估计是由于集合管梗阻而形成的囊肿,经年累月接受其所属肾单位分泌的微量尿液,在浓缩功能差的情况下,潴留囊肿内的晶体便保持糊状微粒状态。本例钙乳沉积物的化学分析表明,其成份含有9种元素,其中以钙、铝、硅、及镁含量最多。x线检查的特征性图像是诊断本症的主要方法。囊肿去盖术对本症是一种安全而有效的术式。