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61.
OBJECTIVES: This study compared the relative strength of the associations of a set of structural (social, economic, and political) variables and a set of health services variables with state-level infant, neonatal, and postneonatal mortality. It also examined whether health services mediate the relationships between structural variables and state-level infant, neonatal, and postneonatal mortality. METHODS: With the state as the unit of analysis, data for all 50 states were analyzed by means of multiple regression. RESULTS: Structural variables accounted for substantially more variance in infant, neonatal, and postneonatal mortality than health services variables, and health services variables were more strongly related to infant mortality than to neonatal or postneonatal mortality. When health services variables were controlled, the strengths of the associations between the structural variables and infant, neonatal, and postneonatal mortality were reduced but remained statistically significant. CONCLUSIONS: A substantial portion of the variance in state-level infant mortality is accounted for by states' structural characteristics, which are partially mediated by health services.  相似文献   
62.
To compare multiple and singleton pregnancies in the treatment of threatened preterm delivery with prolonged intravenous ritodrine, 32 women with multiple pregnancy (26 twins, 6 triplets, 70 fetuses, 30.3 +/- 3.5 weeks) and 51 women with singleton pregnancy (31.3 +/- 2.6 weeks) admitted for threatened preterm delivery without rupture of the membranes were the subjects of a retrospective study of obstetric data, perinatal outcome and maternal adverse effects. Significance was assessed by chi 2 test and Student's t test. Multiple pregnancies were associated with a marked increase in the duration of tocolysis (17.2 +/- 17.3 vs. 7.6 +/- 8.1 days, P < 0.01), incidence of delivery before 37 weeks (87.5 vs. 35.3%, P < 0.01) and incidence of maternal cardiovascular complications (34.4 vs. 4.0%, P < 0.01), including three cases of pulmonary edema. The incidences of delivery before 32 weeks (12.5 vs. 7.8%) and of neonatal death (2.9 vs. 0%) were not significantly different in the two groups. Multiple pregnancies dramatically increased the incidence of maternal adverse effects of prolonged intravenous ritodrine therapy. Neonatal benefit is questionable and was difficult to establish since it was not a randomized study.  相似文献   
63.
OBJECTIVE: To examine noradrenergic (NA) function in children with attention-deficit hyperactivity disorder (ADHD) by replicating and expanding upon a previous finding that ADHD children with and without reading disabilities (RD) differ in plasma levels of the NA metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG). METHOD: Plasma levels of MHPG were compared in ADHD children who were subdivided on the basis of the presence or absence of RD. Subsequently, this replication sample was combined with a previously studied sample to further explore the relationship between plasma MHPG levels and measures of cognitive function in children with ADHD. RESULTS: Plasma levels of MHPG were significantly lower in ADHD children without RD, compared with those with RD, replicating a published finding. Analyses in the combined sample indicated that, among children with ADHD, plasma MHPG levels were inversely associated with measures of academic achievement and verbal processing, but not parent or teacher ratings of behavior or continuous performance test measures of attention and impulsivity. CONCLUSIONS: These data indicate that children with ADHD are not homogeneous with regard to NA function and that neurochemical variation is closely associated with differences in clinical characteristics of the children.  相似文献   
64.
磺酸型介孔材料催化合成甲基葡萄糖苷   总被引:2,自引:0,他引:2  
魏莉  孙健  翟尚儒  王迎  赵吉祥  王少军 《现代化工》2012,32(6):68-70,72
以甲醇和葡萄糖为原料,采用一步合成法合成甲基葡萄糖苷。以磺酸型介孔材料作为催化剂,借助扫描电子显微镜、高分辨率透射电子显微镜、低温氮气吸附/脱附、热重分析等方法研究了材料的结构和性能。实验结果表明,催化剂用量为0.6g,醇糖摩尔比为28∶1,反应温度为115℃,反应时间为2 h为最佳反应条件,此条件下合成产物的收率可达95.67%。同时使用Fourier红外光谱仪对产物进行了表征。  相似文献   
65.
研究 AZ91D 镁合金在邻苯二甲酸氢钾-硼酸盐碱性环保型电解液中的阳极氧化行为。考察邻苯二甲酸氢钾对阳极氧化膜层性能的影响,并利用扫描电镜(SEM)、X 射线衍射(XRD)、动电位极化和电化学阻抗(EIS)进行分析表征。结果表明,邻苯二甲酸氢钾的浓度对阳极氧化成膜过程,氧化膜的表面形貌、厚度、相结构和耐腐蚀性能都有重要影响。在硼酸盐电解液中加入适量的邻苯二甲酸氢钾以后,制得的阳极氧化膜表面光滑、致密,与镁合金基体的结合力强,具有优异的耐腐蚀性能。  相似文献   
66.
孟庆云  张健  田丽芳  吴大鸣 《塑料》2008,37(3):72-74
利用ISBS方法制备PP/纳米SBR复合材料。通过SEM和力学性能测试,研究了纳米SBR在复合材料中的分散状况,并考察了不同纳米SBR的添加对PP力学性能的影响。结果表明:纳米SBR在基体PP中实现了纳米级分散;且纳米SBR的添加量为7%时,复合材料PP/纳米SBR的力学性能最佳,其中缺口冲击强度提高了80%。  相似文献   
67.
介绍了ABS塑料电镀三价黑铬的工艺流程,主要包括除油,亲水,粗化,中和,预浸,催化,加速,化学镀镍,活化,镀铜,微蚀,镀光亮镍,镀三价黑铬,钝化和烘干.给出了三价黑铬镀液的配方,阐述了各组分的作用及工艺奈件对镀层的影响,介绍了常见故障的处理方法.  相似文献   
68.
宁夏西部聚氯乙烯有限公司在电石装置供电系统中安装过电压吸收装置、限流电抗器和接地消弧自动跟踪补偿装置,避免了供电系统过电压、短路电流和电容电流对电气设备的危害,生产1 t电石耗电量由3 579.25 kW·h降到3 553.89 kW·h.  相似文献   
69.
Inspired by the incorporation of metallocene functionalities into a variety of bioactive structures, particularly antimicrobial peptides, we endeavored to broaden the structural variety of quaternary ammonium compounds (QACs) by the incorporation of the ferrocene moiety. Accordingly, 23 ferrocene-containing mono- and bisQACs were prepared in high yields and tested for activity against a variety of bacteria, including Gram-negative strains and a panel of clinically isolated MRSA strains. Ferrocene QACs were shown to be effective antiseptics with some displaying single-digit micromolar activity against all bacteria tested, demonstrating yet another step in the expansion of structural variety of antiseptic QACs.  相似文献   
70.
In insect cell-baculovirus expression systems for recombinant protein production, it is sometimes necessary to supplement cultures with protease inhibitors to protect recombinant proteins against proteolysis. To date, however, there is no information available concerning protease activities in inhibitor-supplemented cultures. The aim of the present study was to investigate intracellular and extracellular protease activities in cultures of virus-infected Sf-9 insect cells which were supplemented with inhibitors against carboxyl and cysteine proteases produced during culture. Prior to the supplementation culture, the cell toxicity of several protease inhibitors was determined. As a result, pepstatin A (carboxyl protease inhibitor) and E64, cystatin, leupeptin, and antipain (cysteine protease inhibitors) tested in this study showed no apparent negative effects on the growth and viability of noninfected Sf-9 insect cells at low concentrations. In addition, E64 and pepstatin A could rapidly permeate virus-infected Sf-9 cells and inhibit the respective intracellular protease activities. A virus-infected culture with a multiplicity of infection of 1 was carried out with E64 and pepstatin A which were added to the culture medium at 2 d post-infection. As a result of inhibitor supplementation, the cellular activity for recombinant protein biosynthesis was reduced by 5-30%. However, a significant reduction in carboxyl and cysteine protease activities was observed not only in the medium but also intracellularly. This is the first study that directly demonstrates a reduction in extracellular and intracellular protease activities in protease inhibitor-supplemented cultures of virus-infected insect cells.  相似文献   
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