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Li_2B_4O_7晶体压电性能及应用的研究 被引量:1
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作者 刘景和 李建利 +3 位作者 邢洪岩 李艳红 姚兰芳 周稳锁 《人工晶体学报》 EI CAS CSCD 北大核心 2000年第S1期176-,共1页
Li2 B4O7(简称LBO)晶体是一种性能优异的压电晶体材料 ,特别适合于制作高频、宽带、低插入损耗的声表面波 (SAW)和体波 (BAW)器体。本文采用导纳圆图法和脉冲回波法测得LBO晶体的弹性及压电系数。从测试结果可以看出 ,弹性系数的交叉分... Li2 B4O7(简称LBO)晶体是一种性能优异的压电晶体材料 ,特别适合于制作高频、宽带、低插入损耗的声表面波 (SAW)和体波 (BAW)器体。本文采用导纳圆图法和脉冲回波法测得LBO晶体的弹性及压电系数。从测试结果可以看出 ,弹性系数的交叉分量少 ,且数值相对较小 ;在 ( 0 0 1 )面内有较高的声波传播速度 ,其变化范围为 6 5 0 0~ 70 80m/s ,在 [0 0 1 ]方向有较低的声波传播速度 ,大约为 5 1 6 0m/s;而压电性能反映了在不同方向的机电耦合系数均比石英晶体相应参数大得多。该晶体具有较高的K2 S 值 ,机械加工性能良好 ,莫氏硬度 6 ,小于石英 ,可方便地用于制造谐振器。制作工艺与石英基本相同 :定向切割研磨清洗电极装架调频封装。谐振器性能测试结果与石英的比较表明谐振器的频率温度特性为抛物线型 ,转变温度在 - 1 0~ 5 5℃范围内 ,频率变化为 3× 1 0 -4 。这种晶体还具有良好的频谱响应 ,寄生频率高出主频 1 80kHz,衰减大于 30dB ,完全可以满足器件的使用要求。利用LBO晶体机电耦合系数较高的特点 ,还可以制作出调频范围较宽的压控振荡器 ,性能的测试结果表明可调性为 0 .47% ,比石英晶体振荡器 (可调性为 0 .0 4% )大 1 0倍。宽带晶体滤波器一般是由石英滤波器加展宽线圈制成的 。 展开更多
关键词 Li_2B_4O_7晶体 压电性能 声表面波器件
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愈肺宁方对慢性阻塞性肺疾病稳定期患者诱导痰炎症细胞和LTB_4的影响 被引量:1
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作者 洪春霖 洪敏俐 +6 位作者 陈慧暖 柯庚申 黄小华 刘燕鸿 高凌云 陈文喜 李风森 《世界科学技术-中医药现代化》 2015年第12期2517-2521,共5页
目的:探讨愈肺宁方(简称愈肺宁)对慢性阻塞性肺疾病(COPD)稳定期患者诱导痰炎症细胞及诱导痰和血浆白三烯B_4(LTB_4)的影响。方法:采用随机双盲安慰剂对照研究,将COPD稳定期患者60例分成愈肺宁治疗组(简称治疗组)和安慰剂对照组(简称对... 目的:探讨愈肺宁方(简称愈肺宁)对慢性阻塞性肺疾病(COPD)稳定期患者诱导痰炎症细胞及诱导痰和血浆白三烯B_4(LTB_4)的影响。方法:采用随机双盲安慰剂对照研究,将COPD稳定期患者60例分成愈肺宁治疗组(简称治疗组)和安慰剂对照组(简称对照组),每组30例,在基础治疗的同时分别给予愈肺宁和安慰剂治疗,连续8周,检测治疗前后患者诱导痰中炎症细胞及诱导痰和血浆LTB_4水平。结果:治疗组实际完成28例,对照组实际完成27例,治疗组治疗后诱导痰白细胞和中性粒细胞浓度降低(P<0.05),诱导痰LTB_4水平未见明显改变,血浆LTB_4水平明显降低(P<0.05);对照组治疗后诱导痰白细胞和中性粒细胞无明显改变,诱导痰LTB_4水平反而升高(P<0.05),血浆LTB_4无明显改变;COPD患者的诱导痰白细胞、中性粒细胞和巨噬细胞分别与LTB_4呈弱的正相关(r=0.359、r=0.341和r=0.260,均P<0.01)。结论:愈肺宁可以降低COPD稳定期患者诱导痰炎症细胞和血浆LTB_4水平,并阻止诱导痰LTB_4水平进一步升高,说明愈肺宁可能通过降低LTB_4以减轻气道炎症,这可能是愈肺宁治疗COPD的机制之一。 展开更多
关键词 慢性阻塞性肺疾病 愈肺宁方 诱导痰 气道炎症 白三烯B_4
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Vitamin D_3在儿童桥本甲状腺炎的水平及对IL-4、IFN-γ的影响 被引量:3
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作者 王栋钢 熊丰 雷培芸 《广东微量元素科学》 CAS 2006年第10期25-28,共4页
通过体外实验,直接从T细胞水平,在1α,25(OH)2D3的干预下,分别以IFN-γ、IL-4作为Th1、Th2的代表,分析人周围血单个核细胞(PBMC)中IFN-γ和IL-4在HT中的细微变化以及血清25(OH)D3水平,探讨1α,25(OH)2D3对HT细胞因子的影响。以27例HT患... 通过体外实验,直接从T细胞水平,在1α,25(OH)2D3的干预下,分别以IFN-γ、IL-4作为Th1、Th2的代表,分析人周围血单个核细胞(PBMC)中IFN-γ和IL-4在HT中的细微变化以及血清25(OH)D3水平,探讨1α,25(OH)2D3对HT细胞因子的影响。以27例HT患儿为研究对象,17名健康儿童作对照,采集静脉血,部分用于分离其PBMC,并用PHA活化T细胞并培养,设1α,25(OH)2D3干预组和对照组,收集培养上清液。ELISA检测上清液IL-4、IFN-γ水平。同时另一部分静脉血分离出血清,并提取25(OH)D3,用放射免疫法(RIA)测定其水平。结果表明,HT组25(OH)D3水平显著低于健康对照,分别为(21.85±5.73)ng/mL和(27.56±7.46)ng/mL(P<0.01),且HT组PBMC产生IFN-γ水平显著高于健康对照,分别为(2 146.15±355.01)pg/mL和(1 462.00±101.52)pg/mL(P<0.01),而IL-4的表达显著低于健康对照,分别为(52.26±7.17)pg/mL和(59.32±4.21)pg/mL(P<0.01)。1α,25(OH)2D3干预后HT患儿IFN-γ表达显著下调,为(1 536.00±243.95)pg/mL(P<0.01),IL-4的变化不明显。提示HT患儿的25(OH)D3水平严重不足,1α,25(OH)2D3能通过抑制HT增强的IFN-γ分泌,纠正Th1、Th2细胞因子失衡,理论上1,α25(OH)2D3可改善儿童HT Th1、Th2细胞因子失衡。 展开更多
关键词 活性维生素D3 桥本甲状腺炎 IL-4 IFN-Γ
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Li_2B_4O_7晶体非线性光学性能的研究
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作者 李建利 刘景和 +3 位作者 邢洪岩 李艳红 张希艳 姚兰芳 《人工晶体学报》 EI CAS CSCD 北大核心 2000年第S1期177-,共1页
近年来 ,Furusawa研究了这种晶体的拉曼散射光谱和二次谐波产生 ,发现Li2 B4O7晶体具有非线性光学性能 ,我们采用CZ法生长出40× 40mm的Li2 B4O7晶体 ,采用Maker条纹技术测量了Li2 B4O7晶体的二次谐波系数d3 1和d3 3 。样品尺寸为... 近年来 ,Furusawa研究了这种晶体的拉曼散射光谱和二次谐波产生 ,发现Li2 B4O7晶体具有非线性光学性能 ,我们采用CZ法生长出40× 40mm的Li2 B4O7晶体 ,采用Maker条纹技术测量了Li2 B4O7晶体的二次谐波系数d3 1和d3 3 。样品尺寸为 5mm× 5mm× 0 .3mm ,其表面经光学抛光。光源用Q开关YAG激光。格兰棱镜调节光强并使光成为偏振光。λ/2波片用于改变入射光偏振方向。入射光经滤波片 1 ,以保证入射到样品上的光为 1 .0 6 4 μm基频光 ,出射光经滤波片 2 ,以保证接收到的是倍频信号。二次谐波信号由光电倍增管接收 ,经Boxcar积分平均后由X Y纪录仪纪录。为校正系统 ,用Z 切石英晶体作为参考样品。结果表明 ,Li2 B4O7晶体二次谐波系数d3 3 是石英体d11( 1 .1× 1 0 -9esu)的三倍 ,而相干长度相近。这不仅为进一步研究Li2 B4O7的铁电性提供科学依据 ,而且揭示出该晶体材料在非线性光学等领域的应用前景。 展开更多
关键词 Li_2B_4O_7晶体 非线性光学晶体 非线性光学性能
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PGE_2与LTB_4在微管对TNF-α合成调节中的作用
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作者 李卓娅 冯新为 《免疫学杂志》 CAS CSCD 北大核心 1995年第4期215-218,共4页
本研究证实完善的微管功能对TNF-α的合成是必要的。如用秋水仙碱(Col)抑制微管聚合,则可减少MΦ产生TNF-αCol对TNF-α的抑制作用部分是由于该药引起前列腺素E_2(PGE_2)升高所致,因为用环加氧酶抑制... 本研究证实完善的微管功能对TNF-α的合成是必要的。如用秋水仙碱(Col)抑制微管聚合,则可减少MΦ产生TNF-αCol对TNF-α的抑制作用部分是由于该药引起前列腺素E_2(PGE_2)升高所致,因为用环加氧酶抑制剂消炎痛(Indom,)阻断PGE_2合成,可部分拮抗Col的这一抑制作用。此外,Col可抑制花生四烯酸的另一产物白三烯(LTB_4)的产生,然而补充外源性LTB_4并不影响Col对TNF-α的抑制作用。 展开更多
关键词 肿瘤坏死因子-Α 秋水仙碱 微管 前列腺素E_2 白三烯B_4
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The Effect of Vitamin A on Secretion of IFN-γ and IL-4 in A549 Cells Induced by Mycoplasma Pneumoniae 被引量:2
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作者 吴小兰 刘先洲 汤纪路 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2008年第6期649-652,共4页
In order to investigate the effect of vitamin A (VA) on the secretion of IFN-γ and IL-4 in Mycoplasma Pneumoniae (MP)-induced A549 cells, A549 cells were co-cultured with MP for different time lengths and then th... In order to investigate the effect of vitamin A (VA) on the secretion of IFN-γ and IL-4 in Mycoplasma Pneumoniae (MP)-induced A549 cells, A549 cells were co-cultured with MP for different time lengths and then the levels of IFN-γ and IL-4 in the cell culture supernatants were detected before and after treatment with different concentrations of VA by using the enzyme-linked immu-nosorbent assay ( ELISA). The results showed that the level of IFN-γ and IL-4 in the supernatants of MP-induced A549 cells was much higher than that in non-induced cells (P〈0.01). After application of VA, IL-4 level was not increased until the concentration of VA was up to 0.5×10-5 mol/L (P〈0.01). However, with concentration of VA increased up to 1×10-4 mol/L, IL-4 was significantly suppressed (P〈0.01). It was concluded that MP could induce the secretion of IFN-γ and IL-4 in A549 cells. VA could inhibit the secretion of IFN-γ and increase the IL-4 level in MP-induced A549 cells. However, high concentration of VA had an inhibitory effect on the secretion of IL-4 as well as on the IFN-γ. These data provided a theoretical basis for the application of VA in MP pneumonia in the clinical practice. 展开更多
关键词 Mycoplasma pneumoniae vitamin A IFN-Γ IL-4
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Vitamin D deficiency: Correlation to interleukin-17, interleukin-23 and PⅢNP in hepatitis C virus genotype 4 被引量:12
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作者 Mona F Schaalan Waleed A Mohamed Hesham H Amin 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第28期3738-3744,共7页
AIM: To assess vitamin D (Vit D) abnormalities in hepatitis C infected patients and their relationship with interleukin (IL)-17, IL-23 and N-terminal propeptide of type Ⅲ pro-collagen (PⅢNP) as immune response media... AIM: To assess vitamin D (Vit D) abnormalities in hepatitis C infected patients and their relationship with interleukin (IL)-17, IL-23 and N-terminal propeptide of type Ⅲ pro-collagen (PⅢNP) as immune response mediators. METHODS: The study was conducted on 50 Egyptian patients (36 male, 14 female) with hepatitis C virus (HCV) infection, who visited the Hepatology Outpatient Clinic in the Endemic Disease Hospital at Cairo University. Patients were compared with 25 ageand sexmatched healthy individuals. Inclusion criteria were based on a history of liver disease with HCV genotype 4 (HCV-4) infection (as new patients or under followup). Based on ultrasonography, patients were classified into four subgroups; 14 with bright hepatomegaly; 11 with perihepatic fibrosis; 11 with hepatic cirrhosis; and 14 with cirrhosis and hepatocellular carcinoma (HCC).Total Vit D (i.e., 25-OH-Vit D) and active Vit D [i.e., 1,25-(OH) 2 -Vit D] assays were carried out using commercial kits. IL-17, IL-23 and PⅢNP levels were assayed using enzyme linked immunosorbent assay kits, while HCV virus was measured by quantitative and qualitative polymerase chain reaction. RESULTS: Levels of Vit D and its active form were significantly lower in advanced liver disease (hepatic cirrhosis and/or carcinoma) patients, compared to those with bright hepatomegaly and perihepatic fibrosis. IL-17, IL-23 and PⅢNP levels were markedly increased in HCV patients and correlated with the progression of hepatic damage. The decrease in Vit D and active Vit D was concomitant with an increase in viral load, as well as levels of IL-17, IL-23 and PⅢNP among all subgroups of HCV-infected patients, compared to normal healthy controls. A significant negative correlation was evident between active Vit D and each of IL-17, IL-23 and PⅢNP (r = -0.679, -0.801 and -0.920 at P < 0.001, respectively). HCV-infected men and women showed no differences with respect to Vit D levels. The viral load was negatively correlated with Vit D and active Vit D (r = -0.084 and -0.846 at P < 0.001, respectively), and positively correlated with IL-17, IL-23 and PⅢNP (r = 0.951, 0.922 and 0.94 at P < 0.001, respectively). Whether the deficiency in Vit D was related to HCVinduced chronic liver disease or was a predisposing factor for a higher viral load remains to be elucidated. CONCLUSION: The negative correlations between Vit D and IL-17, IL-23 and PⅢNP highlight their involvement in the immune response in patients with HCV-4related liver diseases in Egypt. 展开更多
关键词 vitamin D INTERLEUKIN-17 INTERLEUKIN-23 N-terminal propeptide of type pro-collagen Hepatitis genotype 4
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高效液相色谱法测定维生素B_4片的含量 被引量:4
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作者 李小燕 《中国药品标准》 CAS 2002年第6期54-56,共3页
目的:建立HPLC法测定VB_4片的含量。方法:采用日本岛津ODS色谱柱(5mm×150mm,粒度:5μm),以甲醇—水(20:80)为流动相,流速1.0ml·min^(-1),以甲硝唑为内标物,紫外检测波长为254nm,内标峰面积法定量。结果:HPLC法测定VB_4的线性... 目的:建立HPLC法测定VB_4片的含量。方法:采用日本岛津ODS色谱柱(5mm×150mm,粒度:5μm),以甲醇—水(20:80)为流动相,流速1.0ml·min^(-1),以甲硝唑为内标物,紫外检测波长为254nm,内标峰面积法定量。结果:HPLC法测定VB_4的线性范围为:40.0~160.Oμg·ml^(-1),相关系数为0.9999,平均回收率为100.3%,RSD为0.51%,精密度试验RSD为0.57%,样品溶液至少在4天内稳定。结论:本方法简便、快速、准确,重现性好,适用于维生素B_4的含量测定。 展开更多
关键词 维生素B4 高效液相色谱法 含量测定
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UPLC法测定维生素B_4片的含量 被引量:1
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作者 张新勇 庄航 +2 位作者 葛雪松 卓静 孙桐 《中国药师》 CAS 2013年第7期1002-1003,共2页
目的:建立UPLC法测定维生素B_4片中维生素B_4的含量的方法。方法:采用ACQUITY UPLC BEH Shield RP18(100 mm×2.1 mm,1.7μm)色谱柱,流动相为0.02 mol·L^(-1)磷酸二氢钾溶液-甲醇(90:10)(加0.5%的三乙胺,用H_3PO_4调pH至为4.0)... 目的:建立UPLC法测定维生素B_4片中维生素B_4的含量的方法。方法:采用ACQUITY UPLC BEH Shield RP18(100 mm×2.1 mm,1.7μm)色谱柱,流动相为0.02 mol·L^(-1)磷酸二氢钾溶液-甲醇(90:10)(加0.5%的三乙胺,用H_3PO_4调pH至为4.0),流速为0.3 ml·min^(-1),柱温为50℃,检测波长为262 nm。结果:维生素B_4在2.79~139.50μg·ml^(-1)浓度范围内,线性关系良好(r=0.999 8),平均回收率为100.2%,RSD为0.3%(n=9)。结论:本方法简便准确,重复性好,可用维生素B_4片的质量控制。 展开更多
关键词 超高效液相色谱法 维生素B4片 维生素B4
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Thermal behavior of B_4 Cparticles under plasma arc powder surfacing condition 被引量:3
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作者 WANG Xibao ZHANG Wenyue LU Tongli and PENG Jie(Hebei University of Technoligy,300130.Tianjin)(Wenyue.Welding Department,Tianjin Universiy,300072,Tianjin.) 《China Welding》 EI CAS 1996年第2期140-145,共6页
The effect of plasma arc powder surfacing process on the amount of B4C particles in the coating and the thermal behavior of B4C particles in different surfacing stages has been investigated.The results showed that the... The effect of plasma arc powder surfacing process on the amount of B4C particles in the coating and the thermal behavior of B4C particles in different surfacing stages has been investigated.The results showed that the feeding rate of B4C partiles is the most important factor affecting the amount of B4C particles in the surfacing coating among all the surfacing parameters,and the most part of B4C Particles in the coating is nto the remainders of original solid B4C particles,but the consolidation products of the unmelted liquid B4C globules in the pool.The results also showed that the B4C particles would not be melted in the plasma arc column, their melting process mainly takes place in the anode spot region on the surface of the pool when surfacing current is less than 200A. 展开更多
关键词 B_4C plasma arc powder surfacing thermal behavior
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B_4C控制棒高温氧化研究现状
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作者 石兴伟 曹欣荣 赵国志 《核安全》 2012年第2期35-40,共6页
以B_4C为中子吸收材料的反应堆堆芯发生严重损毁时,B_4C与高温蒸汽发生氧化反应,从而对堆芯降级和重新定位产生强烈的影响。综述了近十年来高温范围内B_4C控制棒行为的研究现状和研究成果,归纳总结出B_4C氧化动力学原理及氧化模型,详细... 以B_4C为中子吸收材料的反应堆堆芯发生严重损毁时,B_4C与高温蒸汽发生氧化反应,从而对堆芯降级和重新定位产生强烈的影响。综述了近十年来高温范围内B_4C控制棒行为的研究现状和研究成果,归纳总结出B_4C氧化动力学原理及氧化模型,详细介绍了当前先进的B_4C控制棒行为计算程序,并指出该领域国内研究的不足之处。 展开更多
关键词 严重事故 B_4C 高温氧化 降级
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Studies on Non-potentiometric Piezoelectric Sensor System for Determination of Vitamin B_1
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作者 YUAN Jin bin NIE Li hua YAO Shou zhuo 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2003年第3期280-285,共6页
A piezoelectric sensor responsive to vitamin B 1 was fabricated based on the vitamin B 1 tetraphenylborate ion pair. The general performance characteristics of the sensor are presented here. The proposed sensor sho... A piezoelectric sensor responsive to vitamin B 1 was fabricated based on the vitamin B 1 tetraphenylborate ion pair. The general performance characteristics of the sensor are presented here. The proposed sensor showed a wide working pH range, a good sensitivity and selectivity. The response range is between 1 0×10 -7 -4 9×10 -5 mol/L with a detection limit of 8×10 -8 mol/L at pH 4 0. The selectivity should be attributed to the preferential adsorption of the component ion on the membrane/solution interface. The adsorption behavior of vitamin B 1 on the crystal surface was investigated with a quartz crystal impedance(QCI) system. 展开更多
关键词 Piezoelectric sensor vitamin B_(1) Ion-pair complex
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Vitamin B_(12) Deficiency in Newborns and their Mothers_Novel Approaches to Early Detection,Treatment and Prevention of a Global Health Issue
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作者 Gwendolyn Gramer Georg F.Hoffmann 《Current Medical Science》 SCIE CAS 2020年第5期801-809,共9页
Vitamin B 12 deficiency,mostly of maternal origin in newborns,is a well treatable condition but can cause severe neurologic sequelae.In women of childbearing age and pregnant women worldwide vitamin B12 deficiency has... Vitamin B 12 deficiency,mostly of maternal origin in newborns,is a well treatable condition but can cause severe neurologic sequelae.In women of childbearing age and pregnant women worldwide vitamin B12 deficiency has been reported with frequencies of 10%-50%.Children with vitam in B I2 deficiency are asym ptom atic at birth but may develop severe multisystemic symptoms,including irreversible developmental impairment in the second halfyear of life.Early detection of vitamin B12 deficiency allows for presymptomatic treatment.This article provides an overview over the function of vitamin B12 and discusses causes and frequency of vitamin B12 deficiency in newborns,infants,and women of childbearing age.It describes novel successful approaches to newborn screening(NBS)for vitamin B,2 deficiency and results of a pilot study which performed systematic NBS for vitamin B12 deficiency using so-called second-tier strategies by measuring homocysteine and methylmalonic acid in dried blood spots.Recommendations for diagnostics in mothers of children with vitamin B12 deficiency are described as well as results of systematic work-up in mothers and treatment and follow-up of children with vitamin B12 deficiency detected by NBS.Treatment options of vitamin B12 deficiency are presented including a newly developed standardized supplementation scheme with exclusively oral vitamin BI2 supplementation.Recommendations for preventive approaches to vitamin Bl2 deficiency for children and mothers are stated.Many children worldwide could benefit from systematic inclusion of vitamin B12 deficiency into NBS panels.In addition,preventive approaches to maternal vitamin B12 deficiency should be implemented systematically during maternal care. 展开更多
关键词 vitamin B_(12)deficiency PREVENTION TREATMENT mother and child health newborn screening MATERNAL
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Modified reversed-phase high performance liquid chromatography for the determination of leukotriene B_4 and 5-hydroxyeicosatetraenoic acid in peripheral neutrophils of rabbits
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作者 张敏 尤忠义 +1 位作者 雷政宏 王风君 《Journal of Medical Colleges of PLA(China)》 CAS 1993年第2期192-196,共5页
Modification was made on the reversed-phase high performance liquid chromatography(RP-HPLC)with Yue et al's method as a base.The modified RP-HPLC was used to detect leukotriene B_4(LTB_4)and 5-hydroxyeicosatetraen... Modification was made on the reversed-phase high performance liquid chromatography(RP-HPLC)with Yue et al's method as a base.The modified RP-HPLC was used to detect leukotriene B_4(LTB_4)and 5-hydroxyeicosatetraenoic acid(5-HETE).It was found that the modified method has the merits of simpler procedures,shorter testing time and more satisfactory efficacy. 展开更多
关键词 leukotriene B_4 5-hydroxyeicosatetraenoic acid chromatography high performance liquid NEUTROPHILS animal RABBITS
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Thermochemical Evaluation of Combustion Synthesis of Al_2O_3/B_4C Composite
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作者 Yonghe Liu~(1,2)) Sheng Yin~(1)) Weijing Zhang~(1)) Hoyi Lai~(1)) 1) Materials Science and Engineering School, UST Beijing, Beijing 100083, China 2) School of Materials Science and Engineering, Shandong University of Technology, Jinan 250014 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1998年第2期90-92,共3页
The equilibrium phase and adiabatic temperature for combustion synthesis of Al_2O_3/B_4C employing Al, B_2O_3 and C as starting materials is analyzed by both conventional and CALPHAD method. The adiabatic temperature ... The equilibrium phase and adiabatic temperature for combustion synthesis of Al_2O_3/B_4C employing Al, B_2O_3 and C as starting materials is analyzed by both conventional and CALPHAD method. The adiabatic temperature calculed by CALPHAD method is significantly lower than that obtained by conventional method. The CALPHAD calculation also reveals that the equilibrium phases presented at the adiabatic temperature are different to the desired composites. The adiabatic temperature in this system can be lowered by introducing Al_2O_3 as diluents. The maximum amount of Al_2O_3 that can be added to the system while maintain a self-sustaining combusion mode is 1.3 mol. 展开更多
关键词 THERMOCHEMICAL EVALUATION SHS Al_2O_3/B_4C composite
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Studies on Vitamin D Levels in Serum of HIV Infected Patients: Their Effect on Progression towards AIDS
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作者 Catherine Wanjiru Gichuhi Daniel Kariuki +1 位作者 Andrew Nyerere Malkit Riyat 《World Journal of AIDS》 2014年第4期422-429,共8页
Vitamin D deficiency may be more prevalent among HIV-positive patients than in the general population due to HIV disease-related factors. This study examined the effects of HIV infection and use of antiretroviral drug... Vitamin D deficiency may be more prevalent among HIV-positive patients than in the general population due to HIV disease-related factors. This study examined the effects of HIV infection and use of antiretroviral drugs in serum vitamin D levels in HIV patients visiting Aga Khan University Hospital, Nairobi Kenya from October 2013 to April 2014. The effect of vitamin D status on CD4?cell count and HIV viral load was evaluated to determine the status of disease progression to AIDS. HIV viral load in blood samples was determined using COBAS Ampliprep/TaqMan HIV-1 test kit while CD4?cell counts were done using the fluorescence-activated cell sorter system. The levels of vitamin D in serum were determined using electrochemiluminescence binding assay in Cobas E601 mass analyzers. In addition, selected plasma enzymes were used to evaluate liver function. Higher percentage (49.12%) of deficient vitamin D cases were observed among HIV patients not on ART. Deficient levels of Vitamin D were associated with abnormal selected liver enzymes. High viral load was observed among patients not on ART with deficient and insufficient vitamin D. The CD4?cell count was higher in patients on ART with sufficient vitamin D levels compared to those with deficient vitamin D. These observations suggest a need to supplement ART with vitamin D in order to ameliorate Vitamin D deficiency as a strategy to improve HIV management. 展开更多
关键词 vitamin D HIV Patients ART VIRAL Load CD4 COUNT
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Infrared and MAS NMR Spectroscopic Studies of Al_(18)B_4O_(33)
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作者 YOU Hong-peng, HONG Guang-yan and ZENG Xiao-qing (Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China) DENG Feeng and YE Zhao-hui (Laboratory of Magnetic Reso 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2000年第4期301-305,共5页
The IR spectrum and 11B and 27Al MAS NMR spectra of Al18B4O33 are presented and discussed in relation to the possible existence of boron atoms substituting for aluminum atoms. The IR spectrum shows that the strong vi... The IR spectrum and 11B and 27Al MAS NMR spectra of Al18B4O33 are presented and discussed in relation to the possible existence of boron atoms substituting for aluminum atoms. The IR spectrum shows that the strong vibrations of the BO3 groups are present in the 1 500-1 200 cm-1 region, and very weak bands of BO4 units are present in the region from 1 000 to 1 100 cm-1. 11B MAS NMR spectrum indicates that the strong signal for BO3 units appears in the region from δ+5 to δ+20, and the very weak signal for BO4 units is at about δ- 1, while 27Al MAS NMR spectrum shows five peaks at about δ+62, +42. 1, +14, -4. 7 and -6. 4, originating from AlO4, AlO4, AlO5, AlO6 and AlO6, respectively. These results reveal that there are minor BO4 units in Al18B4O33, indicating that a small amount of B atoms substitute for Al atoms in the 4-fold coordination. 展开更多
关键词 Al-18B_4O_33 IR spectrum ^(11)B ^(27)Al MAS NMR spectrum
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Thermally degraded palm kernel oil increased serum 4-hydroxynonenal protein adduct formation and hepatotoxic indications in Wistar rats:vitamin C intervention
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作者 Emeka Chinedu Ifediba Onyenmechi Johnson Afonne 《Toxicology Advances》 2023年第1期1-8,共8页
Objective:The frequent consumption of deep-fried foods has been linked to high risk of certain non-communicable diseases.As a consequence,the safety of deep-fried oil(DFO)ingested with fried foods has been called into... Objective:The frequent consumption of deep-fried foods has been linked to high risk of certain non-communicable diseases.As a consequence,the safety of deep-fried oil(DFO)ingested with fried foods has been called into question.This study therefore evaluated the effects of DFO from palm kernel on serum 4-hydroxynonenal protein adduct formation,De Ritis ratio(DRR),liver histology and atherogenicity in Wistar rats and the role of vitamin C intervention.Methods:Deep-fried oil samples were characterized for total antioxidant capacity(TAC),degradation and metal contamination levels and compared against counterpart unused frying oil(UFO).In the animal experiment,both oil samples,sourced from commercial cooks,were orally administered,for 13 weeks,to sixty-two rats randomly divided into six test groups of two exposure levels alongside vitamin C control.After exposure,serum liver enzyme activities and lipoproteins levels were determined using colorimetric methods,while protein adducts levels were determined using enzyme-linked immunosorbent assay(ELISA).Histopathological examinations of liver tissues were also performed.Results:DFO had significantly lower(P=0.021)TAC,significantly higher(P=0.024)volatile acid and Pb concentrations compared to UFO.Exposure to DFO significantly increased(P<0.01)serum protein adduct formation,the De Ritis ratio and caused cytoplasmic vacuolation and pigment deposit on liver tissues compared to the control.Additionally,DFO exposures had an initial negative body weight gain rate that increased at the end of the study.Conclusion:However,co-administration of vitamin C significantly reduced(P<0.05)the De Ritis ratio and reduced the serum protein adducts levels by at least 15%.Concomitant intake of vitamin C and DFO can mitigate probable adverse effects. 展开更多
关键词 deep-fried 4-HYDROXYNONENAL HEPATOTOXICITY vitamin C oil octanoic
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计算化学模拟法对制备乙硼烷和甲硅烷反应类型的研究
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作者 吕仁庆 王淑涛 +1 位作者 王芳 沈国平 《文山学院学报》 2024年第2期18-23,共6页
采用计算化学模拟方法,在MP2/6-311+g(d)、HF/6-311+g(d)水平上考察了BCl_(3)、B_(2)H_(6)、LiCl、LiAlH_(4)、AlCl_(3)、SiCl_(4)、SiH_(4)中的Mulliken电荷、自然布局分析电荷(NPA电荷)、Hirshfeld布局电荷、原子偶极矩校正的Hirshfel... 采用计算化学模拟方法,在MP2/6-311+g(d)、HF/6-311+g(d)水平上考察了BCl_(3)、B_(2)H_(6)、LiCl、LiAlH_(4)、AlCl_(3)、SiCl_(4)、SiH_(4)中的Mulliken电荷、自然布局分析电荷(NPA电荷)、Hirshfeld布局电荷、原子偶极矩校正的Hirshfeld布局电荷(ADCH电荷),并对它们进行了拓扑结构分析,从而确定了各化合物中原子的氧化数。模拟结果表明,反应4BCl_(3)+LiAlH_(4)=2B_(2)H_(6)+3LiCl+3AlCl_(3)可以视为氧化还原反应,而反应SiCl_(4)+LiAlH_(4)=SiH_(4)+LiCl+AlCl_(3)是取代反应。 展开更多
关键词 LiAlH_(4) B_(2)H_(6) SiH_(4) 氧化还原反应 取代反应
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叶酸联合维生素B_(12)治疗伴高同型半胱氨酸血症的勃起功能障碍患者的效果
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作者 唐钊 吴春磊 +4 位作者 余沁楠 朱峰 薛向东 贺俊 张会清 《河南医学研究》 CAS 2024年第12期2113-2116,共4页
目的探究叶酸联合维生素B_(12)治疗伴高同型半胱氨酸血症(HHcy)的勃起功能障碍(ED)患者的效果。方法选择2021年6月至2022年8月于新乡医学院第一附属医院门诊确诊的61例伴有HHcy的ED患者,按照患者意愿分为观察组及对照组。最终观察组入... 目的探究叶酸联合维生素B_(12)治疗伴高同型半胱氨酸血症(HHcy)的勃起功能障碍(ED)患者的效果。方法选择2021年6月至2022年8月于新乡医学院第一附属医院门诊确诊的61例伴有HHcy的ED患者,按照患者意愿分为观察组及对照组。最终观察组入组37例,对照组入组22例。观察组口服叶酸片及维生素B_(12)片;对照组无药物干预。分别测定两组治疗前和治疗12周后的血浆同型半胱氨酸(Hcy)、维生素B_(12)、叶酸水平,使用国际勃起功能评分量表(IIEF-5)评定勃起功能状态。结果治疗前后,对照组血浆Hcy、叶酸、维生素B_(12)水平及IIEF-5评分比较差异无统计学意义(P>0.05);治疗后观察组血浆叶酸、维生素B_(12)水平及IIEF-5评分升高,且高于对照组(P<0.01),血浆Hcy水平下降,且低于对照组(P<0.01)。结论叶酸联合维生素B_(12)治疗方案可以降低伴HHcy的ED患者的血浆Hcy水平,改善勃起功能。 展开更多
关键词 勃起功能障碍 高同型半胱氨酸血症 叶酸 维生素B_(12)
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