缺磷对皱纹盘鲍贝壳生物矿化的影响

以皱纹盘鲍（Haliotis discus hannai Ino）成鲍为对象，采用“平珠”技术，将圆形玻片插入鲍鱼的外套膜外腔，配制了2种不同磷含量的半精制饲料，在缺磷的人工海水中喂养鲍鱼40天。养殖结束后取出“平珠”，利用扫描电镜对其超微结构进行了观察，并与正常贝壳作比较。结果发现：磷添加饲料组所得“平珠”具有与正常贝壳一致的矿化结构，而缺磷饲料组所得“平珠”晶体的形成、生长和结构都受到显著影响，方解石的排列失去规律，文石的晶态也变得无规则。本研究证明了“平珠”生成法能够模拟贝壳的自然生长，是研究贝壳生物矿化及其营养学机理的有效途径。同时证明了磷对于维持贝壳的晶体形成、正常生长和结构是必不可少的。     

新型皱纹盘鲍防御素hd-def的cDNA序列分析、基因组克隆及表达研究

从构建的皱纹盘鲍肝肾cDNA文库中筛选到了鲍防御素基因EST.通过序列分析发现该基因的全长cDNA序列编码66个氨基酸残基,其前体由信号肽、前导肽和成熟肽组成.该前体的成熟肽含42个氨基酸(6个Cys),推测分子量为4323Da,等电点为8.02.氨基酸序列同源性分析表明,该多肽与昆虫防御素的相似性较高,最高可达70%.因成熟肽二级结构具有典型的昆虫防御素结构特征,该多肽应属于抗菌肽中的昆虫防御素亚家族,是一种新型抗菌肽,将其命名为鲍防御素hd-def.采用基因组步移法获得了全长4032bp的基因组序列.分析表明,该基因由3个内含子和4个外显子编码组成;3个内含子大小分别为497bp、2357bp和528bp,其中两个内含子存在于编码信号肽的序列中.用鳗弧菌和金黄色葡萄球菌刺激皱纹盘鲍,能诱导hd-def的表达.实验检测了5种组织,发现hd-def基因仅在肝胰腺中表达,具有明显的组织表达特异性;其表达属于诱导型表达,提示该基因可能参与皱纹盘鲍的抗细菌感染.     

从AFLP指纹和标记基因序列看我国养殖的四种鲍的亲缘关系

九孔鲍是我国南方主要的鲍养殖对象,皱纹盘鲍与盘鲍则在北方被广泛养殖。对于皱纹盘鲍与盘鲍,尤其是九孔鲍与杂色鲍的分类关系,迄今学术界还存在着不同看法。本文通过AFLP指纹的比较以及细胞核ITS-1和18SrRNA基因片段、线粒体16S rRNA和COI基因片段DNA序列的比较,发现九孔鲍与杂色鲍之间遗传趋异很小,只达到不同地方群体差异的水平;皱纹盘鲍与盘鲍趋异较大,可以认为是属于不同亚种。本研究结果同时表明AFLP技术是进行鲍种质鉴别和遗传多样性研究的有用手段。     

化妆品中维生素D2、维生素D3含量的测量不确定度评定

对《化妆品安全技术规范》(2015年版)中有关维生素D2和维生素D3高效液相色谱法含量测定进行了不确定度评定,建立了数学模型,考察了不确定度的来源并给出了量化结果,计算出合成标准不确定度和扩展不确定度。结果表明,当置信区间为95%,包含因子k=2,被测化妆品中维生素D2和维生素D3 含量分别为48.84μg/g和45.76μg/g时,其相应标准扩展不确定度分别为10.36μg/g和9.71 μg/g。最后讨论了测量不确定度的主要来源,并提出了改进建议。     

甘油对冷冻干燥保存红细胞抗氧化酶活性的影响

为研究甘油对冷冻干燥保存红细胞的作用机制,测定不同时期冷冻干燥保存-复水的红细胞回收率及超氧化物歧化酶(Superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(Glutathione peroxidase,GSH-Px)、过氧化氢酶(Catalase,CAT)的酶活性.结果显示,保存在25℃下,前90天内的SOD、GSH-Px与CAT的酶活性变化不大,酶活率保持在90%以上;随保存时间延长,180天后细胞回收率由初始的83.5%降低至48.5%,SOD、GSH-Px、及CAT的酶活率分别降低了25.6%、21.5%和18.4%.本实验发现保存过程是引起冻干红细胞SOD、GSH-Px、及CAT酶活性下降的主要原因.     

135孔育苗盘和187孔育苗盘对烟苗素质的影响

为提高南平市烟苗的素质,对135孔漂浮育苗盘和187孔漂浮育苗盘进行对比研究,旨在对比两种漂浮盘的优劣,以便为大面积育苗提供参考。结果表明：135孔育苗模式在苗期和大田的表现优于常规育苗模式,出苗快且长势好。在病害发生情况上来看,以135孔育苗模式病害发生情况较轻,在烟叶内在化学成分方面,以135孔育苗模式处理烤后烟叶化学成分较为协调,同时135孔育苗模式处理的经济性状表现较好。     

固溶和时效温度对7715D钛合金组织和性能的影响

研究了固溶和时效温度对7715D高温钛合金轧棒室温和600℃高温拉伸性能的影响。结果表明,低温固溶材料室温强度高,但高温强度低;低于600℃时效时材料的室温屈服强度和塑性变化不大;高于600℃时效,室温强度略有上升,高温强度降低。组织和拉伸断口分析表明,室温强度与β转变组织大小相关,高温强度受初生α相和β转变组织的相对强度影响更大。建议7715D钛合金在高的固溶温度和适当的时效温度进行热处理,推荐980℃/2 h+600℃/2 h。     

轧制工艺对D6A钢微观组织和力学性能的影响

为了研究轧制工艺对D6A钢组织及力学性能的影响,分别制备了87％和93％压下量的D6A钢,并通过EBSD和拉伸性能测试进行了分析.结果表明,随轧制压下量由87％增加至93％,D6A钢中晶粒尺寸显著减小,由5 μm减至1 μm,小角度晶界含量则大幅增加,由55％增至80％.随轧制压下量的增加,D6A钢的抗拉强度及屈服强度...     

机械振动和半固态等温热处理对消失模 AZ91 D 组织的影响

研究了不同浇注温度下消失模铸造 AZ91 D 镁合金试样,在振动凝固和“ 振动凝固+ 半固态热处理冶 条件下组织的变化情况。 结果表明,对不同浇注温度下消失模铸造 AZ91 D 镁合金试样实施振动凝固都能细化试样的显微组织,且在浇注温度为 740 ℃ ,振动力为 1 . 5 kN 时细化效果最好;对经振动和不振动凝固的试样进行半固态等温热处理,两者的组织都能得到球化,且随着等温时间的延长,两者的组织都会合并长大,其中半固态等温热处理的较佳工艺为 570 ℃ 下保温 10 min。     

Preparation and evaluation of vitamin C and folic acid-coloaded antioxidant liposomes

Vitamin C (VC) and folic acid (FA) are the important nutrients and antioxidants in human body. To protect them from pro-oxidant elements and reveal their co-operation effects, VC-loaded liposomes (VC-Lip), FA-loaded liposomes (FA-Lip), and their coloaded liposomes (VCFA-Lip) are prepared using the modified ethanol injection method in this study. The properties of the prepared liposomes including morphology, encapsulation efficiency, DPPH radical scavenging activity, hydrogen peroxide scavenging activity, and stability are determined and discussed in detail. The experimental results show that the vesicle size of the prepared liposomes are about 100–150?nm. The encapsulation efficiency of VC- and FA-coloaded liposomes is higher than that of the individual loaded ones. In vitro antioxidant activity study shows that the prepared liposomes have excellent antioxidant activity and the co-operation of VC and FA are better than the individual ones. Furthermore, the stability experiment reveals that the coloaded liposomes have a good stability in the relatively low temperature. These results indicate that VC- and FA-coloaded liposomes could be used as an effective antioxidant and it could be applied as a promising delivery system for the antioxidant defense system to food industry.     

Prevalence of 25(OH) vitamin D insufficiency and deficiency in chronic kidney disease stage 5 patients on hemodialysis

Little is known about the magnitude of vitamin D deficiency in patients with stage 5 chronic kidney disease (CKD-5) on hemodialysis (HD). In the present study, we examined the prevalence of vitamin D deficiency in patients with CKD-5 undergoing HD, evaluating the relationship between calcidiol levels with other parameters of mineral metabolism, nutrition/inflammation, functional capacity (FC), and sunlight exposure. Serum 25(OH) vitamin D levels were evaluated in 84 stable patients on chronic HD not receiving vitamin D supplements, with a mean age 58.9+/-16.6 years, during the month of September (end of winter in the southern hemisphere). 25(OH) vitamin D serum levels, intact PTH (iPTH), as well as serum albumin, calcium, phosphorus, and alkaline phosphatase were analyzed in fasting samples. Similarly, protein catabolic rate (PCR) and body mass index (BMI) were determined as nutritional parameters. Functional capacity according to the Karnofsky index, and sunlight exposure were also analyzed. In this study, we considered adequate vitamin D levels those above 30 ng/mL (U.S.A. National Kidney Foundation DOQI Guidelines), vitamin D insufficiency when levels were between 15 and 30 ng/mL, and vitamin D deficiency when levels were below 15 ng/mL. The mean 25(OH) D levels were significantly higher in men than in women (28.6 vs. 18.9 ng/mL; p=0.001). Vitamin D insufficiency was found in 53.5% of the patients (n=45) and vitamin D deficiency in 22.6% (n=19). In the univariate analysis, there were no correlations between 25(OH) D levels with age, iPTH, calcium, or phosphorus. There were positive correlations between serum 25(OH) D levels and degrees of sunlight exposure (R=0.55; p<0.0001), serum creatinine (r=0.38; p<0.001), serum albumin (r=0.22; p=0.04), and a negative correlation with BMI (r=-0.26; p=0.01). In the multiple regression analysis, only sunlight exposure (B=0.361), BMI (B=-0.23), and gender (B=-0.27) were significantly associated with 25(OH) D levels. Patients with FC 1 to FC 2 (n: 70%, 83.3%) had significantly higher 25(OH) D serum levels compared with FC 3 to FC 4 patients (n: 14%, 16.6%): 25.9 vs. 17.1 ng/mL (p=0.03). These results indicate that vitamin D insufficiency/deficiency is highly prevalent (76.1%) at the end of winter, in stage 5 CKD patients on HD, and lower values seem to be related to decreased sunlight exposure, female gender, increased BMI, and worse functional class.     

Effect of vitamin D supplementation on endothelial dysfunction in hemodialysis patients

Introduction: Patients with chronic kidney disease (CKD) commonly experience 25‐hydroxyvitamin D3 (25‐OH‐D3) deficiency, and these patients have a higher incidence of cardiovascular diseases (CVDs) due to endothelial dysfunction (ED). The aim of our study was to investigate the effect of 25‐OH‐D3 deficiency and its supplementation on ED in patients with CKD. Methods: Twenty‐nine uremic patients on dialysis and 20 healthy controls were evaluated for ED by high‐resolution Doppler ultrasonography of the brachial artery. In addition, 25‐OH‐D3‐deficient patients (25‐OH‐D3 < 30 nmol/L) with CKD and healthy controls were evaluated for ED before and after 8 weeks of oral vitamin D (cholecalciferol, 50,000 units) treatment. All subjects were evaluated for percent flow‐mediated dilatation (%FMD), percent endothelium‐independent nitroglycerin‐induced vasodilatation (%NID), and bilateral carotid intima‐media thickness (CIMT). Findings: Patients on dialysis had lower %FMD and %NID 6.11 [2.27–12.74] and 10.96 [5.43–16.4], respectively, than controls 15.84 [8.19–22.49] and 21.74 [12.49–29.4], respectively (P < 0.05). Patients on dialysis had higher left and right CIMT (0.79 ± 0.15 and 0.78 ± 0.14, respectively) than controls (0.60 ± 0.09 and 0.59 ± 0.09, respectively; P < 0.05). In 25‐OH‐D3‐deficient patients with CKD, after vitamin D treatment, %FMD was significantly increased in dialysis patients (10.25 [7.8–12.8]) compared to before supplementation (5.4 [2.77–6.15]; P < 0.001). Discussion: These results indicated that dialysis patients had significantly lower blood 25‐OH‐D3 levels and higher CIMT than healthy subjects. In addition, vitamin D supplementation improved ED and increased %FMD in dialysis patients. Our findings suggest that vitamin D supplementation in dialysis patients might prevent CVD.     

抗氧剂/光稳定剂对3D打印光致变色木塑复合材料性能的影响

功能性光致变色木塑复合材料(PWPC)使用寿命通常较短,因此本研究将抗氧剂1010和光稳定剂770引入到PWPC中,以改善复合材料的力学和耐光疲劳等性能.采用熔融共混法制得杨木粉/聚乳酸(WF/PLA)基光致变色复合材料,通过熔融沉积技术(FDM)打印成型,对制备的WF/PLA复合材料力学、界面相容性、热稳定性和耐光疲...     

合金元素对Cu-Te-Cr合金抗氧化性能的影响

利用氧化增重法,结合SEM、XRD等不同测试手段,研究了不同碲含量的Cu-Te-Cr合金在300～600℃的抗氧化性能.实验结果表明,在纯铜基体中加入Te、Cr元素,合金发生了内氧化,提高了氧化膜和合金基体的结合强度和氧化膜的致密度,增强了氧化膜的粘附性,从而提高了铜合金的抗氧化性能;且随着温度的升高,合金的氧化趋势由抛物线规律向直线规律转变.     

Effect of selective laser melting on microstructure and properties of AZ91D alloy

Selective laser melting technology is used to manufacture porous and solid AZ91D alloys. The effects of laser power and hatch spacing on the density, blowholes, microstructure and mechanical properties of AZ91D alloy are studied. The laser power and hatch spacing play a significant role in the density and blowholes of AZ91D specimens. The grains size of specimens increases from 1 μm–2 μm to 8 μm–10 μm from the bottom to the top in single molten pool. Compared with grain size of die‐casting alloy (30 μm), that of selective laser melted gets refinement. There is no significant change in microstructure in the bottom, middle and top of specimens. The micro‐hardness of AZ91D alloy, reaching up to 115.3 HV 0.1, is superior to that of die‐casting alloy (56 HV 0.1). The compression properties of porous and solid specimens reach the degree of die‐casting solid magnesium alloy. AZ91D alloy shows the potential in the application of medical biodegradable materials.     

三维编织复合材料弹性性能的表面胞体效应

在作者已有的内胞模型基础上, 结合陈利等的面胞纱线走向及Chou 等对表面纤维束截面形状的描述,建立了由面胞和内胞组合的有限元分析模型, 比较真实地模拟了三维四向编织复合材料的真实结构。通过有限元计算预测了其弹性性能, 并同实验结果进行了比较, 分析讨论了三维四向编织复合材料的面胞对整体弹性性能的影响。研究结果证明了面胞在三维四向编织复合材料弹性性能有限元预测中的重要性。