A test for competition between two Gobiomorphus species (Teleostei: Eleotridae) in artificial channels

Abstract– The occurrence of competition between common ( Gobiomorphus cotidianus ) and upland ( G. breviceps ) bullies was tested in summer in artificial channels. Although these species have different life histories, they are morphologically and ecologically similar, and frequently cooccur in New Zealand's fresh waters. Mortality during the test period averaged 11.3±2.4% and 17.7±1.9% for the common bully in triplicate control and experimental channels, respectively; in contrast, upland bully mortality was 2.3±1.9% in the control and zero in the experimental channels. Common bullies showed no significant differences in mean length, weight, condition, and specific growth between the control and experimental tests. For upland bullies, all of the above parameters were significantly less in the controls than the experimentals, an outcome that was indicative of intraspecific competition. Moreover, there was a significant linear trend in the distribution of upland bullies, with their numbers being highest at the upstream end of the channels in both the control and experimental tests. Common bullies showed no such trend, although significantly higher proportions of fish were present towards the central positions in the experimental channels, suggesting there was some displacement of them by upland bullies. It is concluded that interspecific competition is not of major importance between populations of these two eleotrids in small streams, although the abundance and upstream penetration of common bullies may be affected to some extent by interaction with upland bullies.     

Recent advance in cardiac ion channel remodeling in diabetes

Occurrence of lethal cardiac arrhythmia, which is associated with prolongation of the QT interval in electrocardiogram(ECG), is related to increased mortality in the patients with diabetes mellitus (DM). Increased QT interval reflects the prolonged cardiac action potential duration (APD). APD abnormality is based on by cardiac ion channel remodeling induced by DM-related pathological changes. As DM is becoming an important risk factor for atrial fibrillation, the most clinically common arrhythmia, this review mainly summarizes the alterations of ion channel currents and relevant protein expression in diabetic ventricular myocytes to explore the underlying mechanisms of arrhythmia, and also discusses some research achievements from investigating the atrial myocytes in DM.     

新疆混凝土渠道冻害原因及其防治措施

混凝土衬砌渠具有水利用系数大、耐久性好、强度高、便于养护管理等优点,而它的缺点是在在新疆的气候条件下易遭冻胀破坏,影响了渠道的使用功能,因此在渠道设计、施工及运行管理中要充分重视渠道的冻害。     

基于SINUMERIK 802S／802C系统数控车床螺纹加工

螺纹的类型很多，在数控车床中，对于不同系统的车床加工螺纹编程的指令也不尽相同，在SINUMERIK 802S／802C系统数控车床中对普通螺纹和梯形螺纹的加工分别加以分析，指出不同类型的螺纹的加工方法也不相同。     

《中国木本植物种子》

AIM: To test whether ischemic preconditioning (IPC) delays ischemia-induced electrical uncoupling by activation of mitochondrial ATP-sensitive potassium channels (mitoK_ATP). METHODS: Adult rat hearts perfused on a Langendorff apparatus were subjected to 40 min ischemia followed by 30 min reperfusion. Changes in coupling were monitored by measuring whole-tissue resistance. RESULTS: IPC delayed the onset of uncoupling campared to ischemic control; Blocking mitoK_ATP channels before the IPC protocol abolished the delay of uncoupling. The specific mitoK_ATP channel opener diazoxide mimicked the protective effect of IPC. The delay induced by diazoxide was reduced by 5-HD, L-type Ca²⁺ channel inhibitor verapamil and a free radical scavenger N-(2-mercaptopropionyl)glycine. CONCLUSIONS: IPC delays the onset of cellular electrical uncoupling induced by acute ischemia, in which activation of the mitoK_ATP channels may be involved.     

Effect of Ba2+ concentration on L-type Ca2+ channel in hypothalamic neurons

AIM:To investigate the effect of Ba²⁺ concentration on L-type of Ca²⁺ channel in hypothalamic neurons.METHODS:The cell acute isolation technique and cell-attached patch-clamp technique were used.RESULTS:The slope conductance of L-type Ca²⁺ channel were 28.6 pS (110 mmol/L) and 19.1 pS (10 mmol/L), and the open probability (NP₀) obviously different with different Ba²⁺ concentration as carrier. CONCLUSION:Ba²⁺ concentration had the obvious effect on the L-type Ca²⁺ channel.     

Role of Cl- in regulatory volume decrease of nasopharyngeal carcinoma cells

AIM:To clarify the role of Cl^- in regulatory volume decrease (RVD) of nasopharyngeal carcinoma cells (CNE-2Z).METHODS:Analysis of living cell images was used to detect the volume changes following exposure to hypotonic solution. Iron replacement and block of iron channels were also applied in the present study. RESULTS:Extracelluar hypotonic treatment made the cells swell and induced RVD. The RVD was correlated positively to the swelling in the range of 160-230 mOsmol/L. Substitution of gluconate for Cl^- in perfusing solutions markedly increased RVD. Depletion of cellular Cl^- abolished, and chloride channel blockers inhibited RVD. CONCLUSION:Cl^- is the key iron to establish the RVD in CNE-2Z cells. Activation of Cl^- channels and Cl^- efflux are the major mechanisms of RVD.     

高校图书馆藏书资源的来源及扩充途径

藏书量增加相对滞后于文献量快速增长已成为高校图书馆建设和发展中的重要问题。结合图书馆藏书来源分析,提出利用高校图书馆优势,采取多种途径扩充藏书来源和提高藏书质量。在购入途径中,除传统订购、邮购、采编选购、复制外,还可采取回收教职工和学生书籍扩充藏书量,通过专家和读者参与式的现场采购提高藏书质量;在非购入途径中,可通过捐赠、代存、共建专题阅览室或阅览架等方式,充分挖掘高校院系、研究团队、教学科研人员文献资源,扩大馆藏并提高利用率。     

中国农业科普现状及挑战

农业科普不仅是实现农业科技成果有效转化的重要桥梁,更是实现全民农业科学素质提升的关键。研究旨在探索推进中国农业科普面向不同社会群体的现代化发展路径,以期为农业科普发展适应现阶段多元化需求提供可行性建议。主要依据2021年中国科普统计数据,从农业科普人才队伍、传播渠道、基地、经费等角度,通过横向与纵向的科普数据比较,分析当前中国农业科普的现状及问题。总的来说,目前中国农业科普发展整体向好,无论是队伍、渠道和基地都得到了较大发展,但在科普内容供给、趣味性、专用设施以及多元主体参与方面还存在不足。因此,推动中国农业科普发展需要充分优化配置农业科普已有资源,完善新媒体在农业科普方面的运用,实现市场主体的多元投入与农业科普人才的多方参与。     

Membrane-Potential Alteration During K＋ Uptake of Different Salt-Tolerant Wheat Varieties

K＋ is the most abundant cation in plant cells and plays an important role in many ways.K＋ uptake of plant has respect to its salt resistant capacity.There are two categories of channel transportation for plants to uptake K＋,one is through K＋ channels and the other is through nonselective cation channels（NSCCs）.The transmembrane localization of K＋ may change membrane potential（MP）.In this paper,three wheat varieties with different salt tolerance were selected and the MP was measured by microelectrode during K＋ uptake.The results showed that the effects of K＋ uptake on MP through K＋ channels or NSCCs were distinct.K＋ influx through K＋ channels led to MP hyperpolarization,while K＋ influx through NSCCs resulted in depolarization.Diverse MP alteration of wheat varieties with different salt tolerance was mainly due to NSCCs-mediated K＋ uptake.Compared with the salt-tolerant wheat,the MP hyperpolarization during K＋ uptake of saltsensitive wheat was much more evident,probably because of the cation outflux through NSCCs during this process.