Toxicity and bioaccumulation of tributyltin and triphenyltin on oysters and rock shells collected from Taiwan maricuture area

The present study was undertaken to evaluate the toxicity of tributyltin (TBT) on oysters (Crassostrea gigas) and bioaccumulation of TBT and triphenyltin (TPhT) on oysters and rock shells (Thais clavigera) from mariculture areas of Taiwan. When treated with concentrations of 0.08, 0.40, 2.00, 10.00 and 50.00 microg TBT/L, the 48-, 72-, 96- and 120-h LC50s of oysters were 44.6, 18.4, 17.9 and 14.3 microg TBT/L, respectively. In the bioaccumulation experiments, oysters and rock shells were exposed to various concentrations of organotins, i.e. A: control, B: 0.40 microg TBT/L, C: 0.40 microg TPhT/L, and D: 0.20 microg TBT/L + 0.20 microg TPhT/L. In general, TPhT was faster accumulated than TBT in both oysters and rock shells and oysters had a higher elimination capability than rock shells. Additionally, greater bioaccumulation and elimination rates had been observed in female oysters than males. To rock shells, the bioaccumulation rate of organotins in imposex females was greater than males and females.     

The radiation patterns of antenna arrays consisting of dipoles coupled to a two-wire transmission line

In this paper the radiation patterns of antenna arrays consisting of dipoles coupled electromagnetically to a two-wire transmission line are reported. The numerical calculation was made on an IBM 650 computer.     

Exploring user experiences as predictors of MMORPG addiction

The overuse of Massively Multiplayer Online Role Playing Games (MMORPGs) is becoming a significant problem worldwide, especially among college students. Similar to Internet addiction, the pathological use of MMORPG is a kind of modern addiction that can affect students’ lives on both a physical and a psychological level. The purpose of this study is to understand MMORPG addiction from a user experience design approach. We first developed a complete model that includes eleven factors (challenge, fantasy, curiosity, control, reward, cooperation, competition, recognition, belonging, obligation and role-playing) to represent users’ experience in MMORPGs. After that, we design a questionnaire to measure student’ gaming experience and level of addiction. Students’ demography information, including gender and game playing habits, was also collected. Four hundred and eighteen Taiwanese college students aged 18–25 years old took part in this online survey. Regression analysis was then conducted to evaluate the relative explanatory power of each variable, with addiction score as the dependent variable and the eleven user experience factors as the independent variables. The results of regression analysis reveal five critical factors (curiosity, role-playing, belonging, obligation and reward) that can be used to predict MMORPG addiction. In addition, this study also infers possible casual mechanisms for increasing college students’ level of addiction. The implications of our findings for both design and educational practitioners were also discussed.     

沥青路面废料冷再生利用试验分析

为了研究沥青路面旧料的性能特点及冷再生技术的可靠适用性,进行了旧料的性能试验分析和以水泥为添加剂的冷再生混合料性能的室内强度试验.试验结果表明:分析旧沥青混合料中沥青和集料性能变化规律可对再生混合料合成级配及添加剂的确定提供依据;在旧料中掺入不同剂量的水泥添加剂和适量的水之后,旧混合料的性质得到改善,提高了旧混合料的抗压强度.研究结果可为冷再生技术的应用提供依据.     

大豆异黄酮对YAC-1 细胞和小鼠ESC艾氏肉瘤生长的抑制作用

目的 观察大豆异黄酮对YAC-1 细胞及小鼠ESC艾氏肉瘤生长的抑制作用及对免疫功能的影响。方法 用MT T 法测定大豆异黄酮对YAC-1 细胞生长的抑制率和小鼠淋巴细胞转化刺激指数;LDH 释放法测定小鼠NK 细胞活性;称重观察肿瘤生长和脾指数和胸腺指数。结果 金雀异黄素和大豆甙元剂量依赖性抑制YAC-1 细胞生长, 并随时间延长作用增强;大豆异黄酮50、100、400 mg·kg^-1 灌胃给药均明显升高雌性小鼠脾指数和淋巴细胞转化的刺激指数, 对雄性小鼠则无明显作用;大豆异黄酮100、400 mg·kg^-1 明显抑制小鼠ESC 艾氏肉瘤生长, 同时50、100、400 mg·kg^-1 均降低异常增高的脾指数, 增加NK 细胞活性。结论 大豆异黄酮明显抑制YAC-1 细胞和小鼠ESC 艾氏肉瘤的生长,同时增强非特异性免疫功能, 并可增强正常雌性小鼠免疫功能。     

LLT探头在厚壁窄间隙焊缝检测中的应用

探讨了LLT技术的基本原理,及其在厚壁窄间隙焊缝检测中的实际应用。同时验证了该技术在实际工件上的检测能力。研究结果表明,LLT技术对垂直于检测面的面积性缺陷有着非常高的检测灵敏度,虽然该技术不能对缺陷进行定量分析,但能够比较准确的对缺陷进行定性,因此,LLT技术可以作为常规检测方法的有效补充。     

TKY管接点焊缝形状模型在相控阵检测中的应用

为解决TKY管节点焊缝超声检测缺陷定位难的问题,针对TKY管节点焊缝复杂的三维空间形状,通过简化并建立了管节点焊缝任意剖面的二维平面模型,并运用计算机编程,实现管节点焊缝上任意位置剖面图的绘制。在此基础上,模拟了管节点焊缝超声相控阵检测的声柬覆盖效果及对反射回波的定位方法。试验还制作了一套带有人工缺陷的TKY试块对以上模型进行验证,并对试验结果进行了分析。     

食品中氯虫苯甲酰胺分析方法研究进展

氯虫苯甲酰胺是美国杜邦公司开发的新型邻甲酰氨基苯甲酰胺类杀虫剂,具有杀虫谱广、速效性好、持效期长的特点,在蔬菜、瓜果、水稻等作物上广泛使用。该药对人体健康具有潜在危害性,许多国家对其残留限量做出明确规定。为满足不同氯虫苯甲酰胺限量的检测要求,发展简单、快速、灵敏、可靠的检测方法尤为重要。本文综述了近年来国内外食品中氯虫苯甲酰胺的主要检测技术及其研究进展,包括固相萃取、分散固相萃取等样品前处理方法,以及液相色谱、液相色谱-质谱联用等分析方法,以期为今后食品中氯虫苯甲酰胺的分析研究提供参考。     

一种新型抽油井双液压调防冲距碰调器的研制

在稠油开采过程中,由于蜡、砂、垢等因素影响,常常出现固定凡尔、游动凡尔被粘附,造成漏失,产量下降;或者凡尔失灵不出油等情况,解决办法就是通过碰泵,消除阀球所粘脏垢,使油井恢复生产.碰泵后需重新调整防冲距,传统的碰调工作没有专用工具,操作麻烦,劳动强度大,安全系数低,停井时间长.而一种新型稠油井双液压调防冲距碰调器解决了以上弊端.新型碰调器由手动液压泵、油缸、高压输油管构成,安全高效,碰调过程由原来的30分钟缩短为2分钟.     

2019—2020年汉中市食源性食品中ST198型肯塔基沙门菌的耐药性研究

目的 ST198型肯塔基沙门耐药性极强,本研究通过对食源性食品中ST198型肯塔基沙门菌的分子流行病学及耐药特性研究,旨在为防控此菌在食源性及其与人类之间的传播提供科学依据。方法 对2019年7月至2020年5月从陕西省汉中市7家不同超市采集的冷冻整鸡和猪肉馅进行肯塔基沙门菌分离鉴定、血清型分型、药物敏感试验及全基因组测序。结果 158份冷冻整鸡和163份猪肉馅中共分离鉴定出127株沙门菌,其中从6家超市共分离到14株ST198型肯塔基沙门菌。药物敏感试验试验显示,14株ST198型肯塔基沙门菌均为多重耐药菌,所有菌株均同时对5类及以上抗菌药物耐药;对左氧氟沙星、多西环素、卡那霉素、链霉素、四环素、萘啶酸、环丙沙星耐药率均达到100%;对头孢唑啉、氨苄西林、头孢噻肟、庆大霉素、氨曲南、头孢吡肟耐药率也达到92.86%;这些菌株仅仅对亚胺培南、美罗培南、多粘菌素完全敏感。其中产ESBLs阳性菌株检出率为92.86%。耐药基因检测显示,14株ST198型肯塔基沙门菌均同时发生染色体上喹诺酮耐药决定区(QRDR)gyrA和parC双突变,突变类型有Asp87Asn(85.71%),Asp87Gly(14.29%),Ser83Phe(100%),Thr57Ser(100%),Ser80Ile(100%)。ESBLs基因以blaCTX-M-55和blaTEM-141为主,78.57%的菌株同时携带这2种基因,14.29%的菌株携带blaCTX-M-14b。78.57%的菌株携带大环内酯类耐药基因mph(A)。系统发育树结果显示,ST198型肯塔基沙门菌在汉中市6家不同的超市间存在相同克隆分子菌株。结论 陕西省汉中市ST198型肯塔基沙门菌主要从冷冻整鸡中分离,对喹诺酮类和三代头孢菌素以及替代药物阿奇霉素耐药严重,ESBLs阳性率和喹诺酮耐药决定区发生突变率高。此菌在汉中市不同超市间有一定传播关系,可能存在交叉污染和上一级污染来源的传播。