梯形明渠水跃共轭水深的优化计算     

金菊良  付强  魏一鸣  丁晶 《东北农业大学学报》2002,33(1):58-62

梯形明渠水跃共轭水深的计算问题在水工消能设计中具有重要意义 ,目前常用的方法有试算法、图解法、近似公式法 ,它们存在计算精度不高、求解复杂、使用不便等缺点。为此 ,本文把该问题等价于两个非线性优化问题 ,建议统一用笔者研制的加速遗传算法 (AGA)来处理。实例的计算结果说明 ,AGA比常用方法简便、计算精度高且具有通用性  相似文献   

Marine Toxins Targeting Ion Channels     

Hugo R. Arias 《Marine drugs》2006,4(3):37-69

This introductory minireview points out the importance of ion channels for cell communication. The basic concepts on the structure and function of ion channels triggered by membrane voltage changes, the so-called voltage-gated ion channels (VGICs), as well as those activated by neurotransmitters, the so-called ligand-gated ion channel (LGICs), are introduced. Among the most important VGIC superfamiles, we can name the voltage-gated Na⁺ (Na_V), Ca²⁺ (Ca_V), and K⁺ (K_V) channels. Among the most important LGIC super families, we can include the Cys-loop or nicotinicoid, the glutamate-activated (GluR), and the ATP-activated (P2X_nR) receptor superfamilies. Ion channels are transmembrane proteins that allow the passage of different ions in a specific or unspecific manner. For instance, the activation of Na_V, Ca_V, or K_V channels opens a pore that is specific for Na⁺, Ca²⁺, or K⁺, respectively. On the other hand, the activation of certain LGICs such as nicotinic acetylcholine receptors, GluRs, and P2X_nRs allows the passage of cations (e.g., Na⁺, K⁺, and/or Ca²⁺), whereas the activation of other LGICs such as type A γ-butyric acid and glycine receptors allows the passage of anions (e.g., Cl⁻ and/or HCO₃⁻). In this regard, the activation of Na_V and Ca_V as well as ligand-gated cation channels produce membrane depolarization, which finally leads to stimulatory effects in the cell, whereas the activation of K_V as well as ligand-gated anion channels induce membrane hyperpolarization that finally leads to inhibitory effects in the cell. The importance of these ion channel superfamilies is emphasized by considering their physiological functions throughout the body as well as their pathophysiological implicance in several neuronal diseases. In this regard, natural molecules, and especially marine toxins, can be potentially used as modulators (e.g., inhibitors or prolongers) of ion channel functions to treat or to alleviate a specific ion channel-linked disease (e.g., channelopaties).  相似文献   

兰花大棚内无线传感器网络433MHz信道传播特性试验   总被引：5，自引：3，他引：2  

李小敏  臧英  罗锡文  李腾  刘永鑫  孔庆军 《农业工程学报》2013,29(13):182-189

不同的应用环境对无线传感器网络的性能有一定的影响。该文针对兰花大棚环境中无线传感器网络节点部署的要求及其应用环境的特性,以433 MHz为载波频率,研究了无线射频信号的传播特性和无线信号与影响因素之间的关系,影响因素包括发射功率、数据包长度、距离、发射端位置等参数,获得了接收信号强度、丢包率等数据,并进行了统计分析。试验结果表明,该无线传感器网络信号的衰减符合对数模型,其决定系数R2最大为0.9246,最小为0.8753;发射功率为0和-5 dBm时,信号较强、通信成功率较高;发射功率处在0和-20 dBm时接收信号强度波动较大;在数据传输速率为1.2 kbps、和调制扩频为高斯频移键控方式等参数确定的情况下数据包的长度对丢包率的影响很小。在上述试验研究的基础上,建立了发射功率和接收信号强度之间的关系模型,模型参数与发射功率之间、传播环境因子n与发射功率之间成二次多项式关系,相关系数分别达到0.9967和0.8686;验证试验结果表明：该模型可以较好地预测不同发射功率不同通信距离的接收信号强度,为兰花大棚无线传感器网络的组建提供支持。此外,设计了接收信号强度三维曲面图和等高曲线图,可直观反映兰花大棚环境下无线信号的传播特性,为今后无线节点布置与组网提供依据。  相似文献   

Expression of volume-activated chloride channel in rat PASMCs treated with hypoxia and hypercapnia and its relationship with MAPK pathway     

LI Guan-long  HUANG Lin-jing  HE Jin-bo  MA Ying-chun  CHEN Hai-e  YING Lei  WANG Yang  WANG Wan-tie 《园艺学报》2014,30(1):25-29

AIM：To investigate the expression of volume-activated chloride channel (CLC3) in rat pulmonary artery smooth muscle cells (PASMCs) treated with hypoxia and hypercapnia and its relationship with MAPK pathway. METHODS：The method of enzyme digestion was used to isolate the PASMCs in male SD rat for cell primary culture. The cells were identified by immunofluorescence cytochemical method with mouse anti-rat α-smooth muscle actin antibody. The rat model of hypoxia and hypercapnia was established. The protein expression of CLC3 was detected by Western blotting. The mRNA expression of CLC3 was determined by RT-PCR. RESULTS：Compared with control group, the mRNA and protein expression of CLC3 in PASMCs was significantly raised in hypoxia and hypercapnia group. Compared with hypoxic and hypercapnic group, the expression of CLC3 was significantly reduced in ERK inhibitor U0126+ hypoxia and hypercapnia group, and was up-regulated in p38 inhibitor SB203580+ hypoxia and hypercapnia group. p38 activator anisomycin significantly decreased the expression of CLC3 at mRNA and protein levels in hypoxia and hypercapnia group. CONCLUSION：The expression of CLC3 at mRNA and protein levels in PASMCs increases under hypoxia and hypercapnia conditions. The ERK1/2 pathway mediates CLC3 expression in PASMCs induced by hypoxia and hypercapnia. Activation of p38 MAPK pathway down-regulates the expression of CLC3 at mRNA and protein levels induced by hypoxia and hypercapnia.  相似文献   

Effect of Danhong injection on respiratory inhibition induced by hypoxia     

LI Li  LIU Wen-yan  LIU Ying 《园艺学报》2014,30(6):1123-1135

AIM：To investigate the effect of Danhong injection on respiratory inhibition induced by hypoxia and its related mechanism. METHODS：The electromyogram of the diaphragm was monitored to observe the respiratory responses of the rats to hypoxia. The expression of acid-sensingion channel 1a (ASIC1a) in the brainstem after hypoxia was detected by the technique of immunohistochemical staining. RESULTS：The respiratory responses of the rats to hypoxia were initiatory excitation and consequent inhibition. In contrast to pre-hypoxia, the respiration of the rats in hypoxia group was inhibited 30 min after hypoxia (P<0.05), but the respiration of the rats in hypoxia plus Danhong group was still excited (P<0.05), indicating that the respiration of the rats in hypoxia plus Danhong group was not yet depressed at the same time. The ASIC1a positive neurons were detected in the nuclei of trapezoid body and solitary tract. Compared with control group, the expression of ASIC1a was obviously enhanced after hypoxia. In contrast to hypoxia group, the expression of ASIC1a in the rats in hypoxia plus Danhong group was remarkably reduced (P<0.05). CONCLUSION：Danhong injection resists the occurrence of respiratory inhibition after hypoxia, and ASIC1a may participate in this process.  相似文献   

Molecular mechanism underlining ethanol-induced chloride currents in nasopharyngeal carcinoma cells     

LIN Na  ZUO Wan-hong  LAI Zhou-yi  WU Jia-bao  CHEN Mei-yuan  WANG Yuan  CHEN Li-xin  WANG Li-wei 《园艺学报》2014,30(7):1179-1183

AIM：To study the effects and mechanisms of ethanol on chloride channels in poorly differentiated nasopharyngeal carcinoma CNE-2Z cells. METHODS：The effect of ethanol on the cell growth was analyzed by MTT assay. The technique of whole-cell patch-clamp was used to detect the chloride current. The characteristics of the chloride current were analyzed by using the chloride channel blockers. The siRNA technique was used to analyze the molecular basis of the ethanol-sensitive chloride channels. RESULTS：Under isotonic conditions, the background current was weak and stable. Ethanol at concentrations of 0.17~170 mmol/L activated a chloride current in a concentration-dependent manner (an inverted U-shape), with a maximum effect at the concentration of 17 mmol/L. The currents showed obviously outward rectification and were susceptible to extracellular hypertonicity and the chloride channel blocker, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). ClC-3 siRNA obviously decreased the currents activated by ethanol. CONCLUSION：Extracellular ethanol induces chloride currents through activating the ClC-3 chloride channels.  相似文献   

Chloride currents activated by cisplatin in poorly differentiated naso-pharyngeal carcinoma cells are not Ca2+-activated chloride currents     

YANG Xiao-ya  LIU Mei  WU Jia-bao  LAI Zhou-yi  WANG Yuan  FAN Ai-hui  ZHU Lin-yan  MAO Jian-wen  WANG Li-wei  CHEN Li-xin 《园艺学报》2014,30(6):968-974

AIM：To investigate the type of chloride channel activated by cisplatin in poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z cells). METHODS：The technique of whole-cell patch-clamp was used to investigate the role of Ca2+ in the activation of cisplatin-activated chloride currents and to analyze the effect of hypertonic stress on these currents in CNE-2Z cells. RESULTS：Chloride currents were induced when the cells were exposed to the calcium-free cisplatin solution, showing the similar density to the currents induced by cisplatin with the presence of extracellular calcium. However, the latency and the peak time of cisplatin-activated currents in the absence of extracellular calcium were prolonged. The activation of cisplatin-activated chloride currents was insensitive to the depletion of intra- and extracellular calcium. Calcium channel antagonist nifedipine had no effect on the cisplatin-activated chloride currents, while hypertonic solution completely inhibited those currents. CONCLUSION：The cisplatin-activated chloride currents are independent on intra/extracellular calcium. The chloride channels activated by cisplatin are not calcium-activated chloride channels, but are probably volume-sensitive chloride channels.  相似文献   

Ion channel mRNA distribution and expression in the sinoatrial node and right atrium of dogs and monkeys     

Tomoya Sano  Hironobu Yasuno  Takeshi Watanabe 《Journal of toxicologic pathology》2021,34(3):223

There are limited data on the gene expression profiles of ion channels in the sinoatrial node (SAN) of dogs and monkeys. In this study, the messenger RNA (mRNA) expression profiles of various ion channels in the SAN of naïve dogs and monkeys were examined using RNAscope^®in situ hybridization and compared with those in the surrounding right atrium (RA) of each species. Regional-specific Cav1.3 and HCN4 expression was observed in the SAN of dogs and monkeys. Additionally, HCN1 in dogs was only expressed in the SAN. The expression profiles of Cav3.1 and Cav3.2 in the SAN and RA were completely different between dogs and monkeys. Dog hearts only expressed Cav3.2; however, Cav3.1 was detected only in monkeys, and the expression score in the SAN was slightly higher than that in the RA. Although Kir3.1 and NCX1 in dogs were equally expressed in both the SAN and RA, the expression scores of these genes in the SAN of monkeys were slightly higher than those in the RA. The Kir3.4 expression score in the SAN of dogs and monkeys was also slightly higher than that in the RA. The mRNA expression scores of Kv11.1/ERG and KvLQT1 were equally observed in both the SAN and RA of dogs and monkeys. HCN2 was not detected in dogs and monkeys. In summary, we used RNAscope to demonstrate the SAN-specific gene expression patterns of ion channels, which may be useful in explaining the effect of pacemaking and/or hemodynamic effects in nonclinical studies.  相似文献   

新式茶饮的运营模式     

罗军  黄智捷  秦佳星 《中国茶叶》2022,(1):19-21

新式茶饮是基于年轻人的饮品喜好,通过茶与食材的搭配,提升饮品的风味和嗜好性,进行产品开发与供应链食材的开发而形成的,主要以年轻人为消费群体的一个茶饮新品类.新茶饮门店运营是要保障把研发室开发的产品,在高频次的出杯中还原研发室开发的产品风味,最终呈现给消费者,并对产品上新、推广方式以及产品退市作出更实用的运营落地方案.文...  相似文献   

“王加”销售业绩差距原因探析及建言     

潘萍萍 《黑龙江八一农垦大学学报》2013,(6):103-107

自加多宝与广药因王老吉商标案决裂以来,双方的斗法大战俨然已演变为更激烈的营销对抗。这是一场空前的商业大战,虽然时间过去不过一年,但双方的营销对抗,胜负似乎已明确,加多宝凉茶高达200亿的年销售业绩与王老吉凉茶不及对方1／5的年销售业绩,已说明了差距。现就双方销售业绩差距及原因进行了分析,指出存在的问题,并针对问题提出相应的对策方案。  相似文献