鼠标上下盖塑料熔体流动平衡分析

借助Moldflow分析软件对鼠标上下盖注射成型过程进行熔体的流动平衡分析,通过不断逼近的迭代计算和调整浇注系统中分流道的直径,达到平衡熔体流动的目的,保证多型腔模具成型的塑件具有良好的质量,缩短了模具设计周期。     

Contamination of shellfish from Shanghai seafood markets with paralytic shellfish poisoning and diarrhetic shellfish poisoning toxins determined by mouse bioassay and HPLC

This paper reports the results of investigations of shellfish toxin contamination of products obtained from Shanghai seafood markets. From May to October 2003, 66 samples were collected from several major seafood markets. Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) toxins in shellfish samples were monitored primarily by a mouse bioassay, then analysed by HPLC for the chemical contents of the toxins. According to the mouse bioassay, eight samples were detected to be contaminated by PSP toxins and seven samples were contaminated by DSP toxins. Subsequent HPLC analysis indicated that the concentrations of the PSP toxins ranged from 0.2 to 1.9 µg/100 g tissues and the main components were gonyautoxins 2/3 (GTX2/3). As for DSP, okadaic acid was detected in three samples, and its concentration ranged from 3.2 to 17.5 µg/100 g tissues. Beside okadaic acid, its analogues, dinophysistoxins (DTX1), were found in one sample. According to the results, gastropod (Neverita didyma) and scallop (Argopecten irradians) were more likely contaminated with PSP and DSP toxins, and most of the contaminated samples were collected from Tongchuan and Fuxi markets. In addition, the contaminated samples were always found in May, June and July. Therefore, consumers should be cautious about eating the potential toxic shellfish during this specific period.     

Validation of Tuba1a as Appropriate Internal Control for Normalization of Gene Expression Analysis during Mouse Lung Development

The expression ratio between the analysed gene and an internal control gene is the most widely used normalization method for quantitative RT-PCR (qRT-PCR) expression analysis. The ideal reference gene for a specific experiment is the one whose expression is not affected by the different experimental conditions tested. In this study, we validate the applicability of five commonly used reference genes during different stages of mouse lung development. The stability of expression of five different reference genes (Tuba1a, Actb Gapdh, Rn18S and Hist4h4) was calculated within five experimental groups using the statistical algorithm of geNorm software. Overall, Tuba1a showed the least variability in expression among the different stages of lung development, while Hist4h4 and Rn18S showed the maximum variability in their expression. Expression analysis of two lung specific markers, surfactant protein C (SftpC) and Clara cell-specific 10 kDA protein (Scgb1a1), normalized to each of the five reference genes tested here, confirmed our results and showed that incorrect reference gene choice can lead to artefacts. Moreover, a combination of two internal controls for normalization of expression analysis during lung development will increase the accuracy and reliability of results.     

二氢杨梅素防治磨损颗粒诱导的小鼠颅骨骨溶解的实验研究

目的: 探讨二氢杨梅素（DMY）对磨损颗粒诱导的小鼠颅骨骨溶解的作用。方法: 选用30只8周龄雄性C57BL/J6小鼠,随机分成3组,每组10只。分别为假手术组（Sham）、阳性对照组（Control）和二氢杨梅素组（DMY）。假手术组手术不加钛颗粒,阳性对照组和DMY组手术时颅骨部位注入30 mg钛颗粒构建小鼠颅骨骨溶解模型。术后DMY组每天连续予500 mg/kg DMY灌胃;假手术组和阳性对照组给予相应体积的生理盐水灌胃。14 d后取眼眶静脉血,随后处死所有实验动物并收集颅骨标本。所有标本行Micro-CT扫描、采集计算机3D重建图像并进行定量分析,随后标本脱钙后以石蜡包埋,进行病理学分析。 结果: Micro-CT扫描3D重建图像显示DMY组小鼠颅骨表面骨溶解严重程度显著低于阳性对照组;Micro-CT扫描显示DMY组小鼠颅骨骨密度明显高于阳性对照组（P<0.05）。HE染色及TRAP染色分析显示,与阳性对照组相比,DMY组小鼠颅骨骨溶解区域破骨细胞数明显减少。DMY组小鼠血清IL-1β、TNF-α、NF-κB受体激活剂配体（RANKL）水平显著低于阳性对照组（P<0.05）;骨保护素（OPG）水平显著高于阳性对照组（P<0.05）。体外细胞培养实验显示,DMY可在体外显著抑制RANKL诱导的破骨细胞分化。结论: DMY可有效抑制磨损颗粒诱导的小鼠颅骨骨溶解。     

Fibroblast Growth Factor 21 Response in a Preclinical Alcohol Model of Acute-on-Chronic Liver Injury

Background and Aims: Fibroblast growth factor (FGF) 21 has recently been shown to play a potential role in bile acid metabolism. We aimed to investigate the FGF21 response in an ethanol-induced acute-on-chronic liver injury (ACLI) model in Abcb4^−/− mice with deficiency of the hepatobiliary phospholipid transporter. Methods: Total RNA was extracted from wild-type (WT, C57BL/6J) and Abcb4⁻/⁻ (KO) mice, which were either fed a control diet (WT-Cont and KO-Cont groups; n = 28/group) or ethanol diet, followed by an acute ethanol binge (WT-EtOH and KO-EtOH groups; n = 28/group). A total of 58 human subjects were recruited into the study, including patients with alcohol-associated liver disease (AALD; n = 31) and healthy controls (n = 27). The hepatic and ileal expressions of genes involved in bile acid metabolism, plasma FGF levels, and bile acid and its precursors 7α- and 27-hydroxycholesterol (7α- and 27-OHC) concentrations were determined. Primary mouse hepatocytes were isolated for cell culture experiments. Results: Alcohol feeding significantly induced plasma FGF21 and decreased hepatic Cyp7a1 levels. Hepatic expression levels of Fibroblast growth factor receptor 1 (Fgfr1), Fgfr4, Farnesoid X-activated receptor (Fxr), and Small heterodimer partner (Shp) and plasma FGF15/FGF19 levels did not differ with alcohol challenge. Exogenous FGF21 treatment suppressed Cyp7a1 in a dose-dependent manner in vitro. AALD patients showed markedly higher FGF21 and lower 7α-OHC plasma levels while FGF19 did not differ. Conclusions: The simultaneous upregulation of FGF21 and downregulation of Cyp7a1 expressions upon chronic plus binge alcohol feeding together with the invariant plasma FGF15 and hepatic Shp and Fxr levels suggest the presence of a direct regulatory mechanism of FGF21 on bile acid homeostasis through inhibition of CYP7A1 by an FGF15-independent pathway in this ACLI model. Lay Summary: Alcohol challenge results in the upregulation of FGF21 and repression of Cyp7a1 expressions while circulating FGF15 and hepatic Shp and Fxr levels remain constant both in healthy and pre-injured livers, suggesting the presence of an alternative FGF15-independent regulatory mechanism of FGF21 on bile acid homeostasis through the inhibition of Cyp7a1.     

活性乳酸菌乳饮品对免疫调节功能的影响

为探讨活性乳酸菌乳饮品对小鼠免疫系统功能的影响,将该饮品按 6.67 ～ 26.66ml/kg BW( 2.5 倍浓缩液)剂量给小鼠灌胃 30 天后,分别检测脾淋巴细胞增殖转化功能( MTT 法),迟发型变态反应性,血清溶血素滴度,碳廓清能力及自然杀伤细胞( NK )杀伤活性.结果表明该乳饮品可明显提高小鼠脾淋巴细胞增殖转化能力,溶血素血清滴度有统计学意义的增加,变态反应性增强,碳廓清能力增强.而 NK 细胞杀伤活性增加不明显,各组间无统计学意义的差异.提示该活性乳酸菌乳饮品具有增强机体免疫功能的作用.     

防鼠型PVC护套料配方研究

本文分析了防鼠 PVC护套料防鼠性能与防鼠剂用量的关系 ,防鼠 PVC护套料物理机械性能及电气性能与树脂、增塑剂、稳定剂、抗氧剂、填充剂等添加剂之间的关系 ,介绍了防鼠 PVC护套料配方的研制过程及配方的性能     

Assessment of PCDD/F,PCB, OCP and BPA dietary exposure of non-breast-fed European infants

The aim of this study is to obtain data on the exposure of non-breast-fed infants to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), and bisphenol A (BPA) and its chlorinated derivatives through consumption of commercial infant foods with largest shares of the market in 22 European Union countries. The E-Screen bioassay was employed to assess the oestrogenicity of the baby foods and the ethoxyresorufin-O-deethylase (EROD) induction was measured to determine the levels of PCDD/F and PCB. Consequently, the highest total effective xenoestrogen burden (TEXB) of 73.60?pM?Eeq?g^?1 was found in the soy-based formula and the EROD bioassay was always below the limit of quantification (LOQ) (3.5?pg?g^?1). Overall, the estimated dietary exposure to BPA via commercial baby foods was lower than the tolerable daily intake (TDI) of 50?µg?kg^?1 body weight (bw). Furthermore, the findings indicated that the dietary exposure of 0–9-month-old infants through the products investigated here does not exceed the maximum TDI of 4?pg WHO-TEQ (toxic equivalents)?kg^?1 bw. However, exposure to more than 2?pg WHO-TEQ?kg^?1?bw?day^?1 might occur for 0–4-month-old infants consuming ‘starting’ hypoallergenic formula. Moreover, analysis of OCP indicated that the dietary exposure of non-breast-fed infants was not harmful. Considering the importance of early development and the vulnerability of infants and children, it is essential to determine their dietary exposure to contaminants in order to decide which efforts of risk reduction should receive highest priority.     

Toxicity assay for deoxynivalenol using Caenorhabditis elegans

The progeny production and development rates of the nematode Caenorhabditis elegans when treated with deoxynivalenol (DON) were examined. Both purified DON and a crude extract from Fusarium graminearum cultured on rice were tested on C. elegans wild-type (Bristol N2) and a mutant strain (AU1). Significant effects (Tukey-HSD, p?<?0.05) on brood size and the rate of larval development from egg to adulthood were observed. Both N2 and AU1 strains showed lower rates of development and smaller brood sizes when exposed to purified DON at concentrations of 500 and 1000?µg?ml^?1 When they were exposed to crude extract containing 250?µg?ml^?1 DON, the inhibition of egg hatching and a greatly reduced development rate were observed. The results suggest that selection of a more sensitive C. elegans mutant strain could be used as a suitable animal model for conducting DON toxicity assays.     

In vitro antifungal activity of terpinen-4-ol,eugenol, carvone, 1,8-cineole (eucalyptol) and thymol against mycotoxigenic plant pathogens

The aim of this study was to examine the effect of five naturally occurring compounds from essential oils on 10 different species of mycotoxigenic fungi involved in several plant diseases. The antifungal activities of terpinen-4-ol, eugenol, carvone, 1,8-cineole (eucalyptol) and thymol were observed in vitro on Fusarium subglutinans, Fusarium cerealis, Fusarium verticillioides, Fusarium proliferatum, Fusarium oxysporum, Fusarium sporotrichioides, Aspergillus tubingensis, Aspergillus carbonarius, Alternaria alternata and Penicillium sp. The naturally occurring compounds tested showed toxic effects on in vitro mycelium growth of all fungal species but with different level of potency. The results are encouraging for further investigations of in planta antifungal activities of these essential oils components.