Eutrophication and algal blooms in channel type reservoirs:A novel enclosure experiment by changing light intensity

To explore eutrophication and algal bloom mechanisms in channel type reservoirs, a novel enclosure experiment was conducted by changing light intensity （LI） in the Daning River of the Three Gorges Reservoir （TGR）. Square enclosures （side 5.0 m） were covered on the surface with shading materials of different thickness, and with their bases open to the river. Changes and characteristics of the main eutrophication factors under the same water quality and hydrodynamic conditions but different LI were evaluated. All experimental water samples were neutral and alkalescent, with high nitrogen and phosphate concentrations, low potassium permanganate index, stable water quality, and different LI. At the same water depth, LI decreased with increasing shade material, while dissolved oxygen and water temperature were both stable. The growth peak of phytoplankton was with light of 345-4390 lux underwater or 558-7450 lux above the water surface, and water temperature of 25.6--26.5℃. Algae were observed in all water samples, accounting for 6 phylum and 57 species, with algal density changing frequently. The results showed that significantly strong or weak light was unfavorable for phytoplankton growth and the function together with suitable temperature and LI and ample sunshine encouraged algal blooms under the same water quality and hydrodynamic conditions. Correlation analysis indicated that algae reduced gradually lengthwise along water depth in the same enclosure while pH became high. The power exponent relationship between chlorophyll a （Chl-a） and LI was found by curve fitting, that is Chl-a = K（LI）n.

Numerical and experimental analyses of hydrodynamic performance of a channel type planing trimaran

This paper studies the hydrodynamic performance of a channel type planing trimaran. A numerical simulation is carried out based on a RANS-VOF solver to analyze the hydrodynamic performance of the channel type planing trimaran. A series of hydrodynamic experiments in towing tank were carried out, in which both the running attitude and the resistance performance of the trimaran model were recorded. Some hydrodynamic characteristics of the channel type planning trimaran are shown by the results. Firstly, the resistance declines significantly, with the forward speed across the high-speed resistance peak due to the combined effects of the aerodynamic and hydrodynamic lifts. Secondly, the resistance performance is influenced markedly by the longitudinal positio- ns of centre of the gravity and the displacements. Besides, the pressure distribution on the hull and the two-phase flow in the channel are discussed in the numerical simulations.

Types and Causes of Debris Flow Damage to Drainage Channels in the Wenchuan Earthquake Area

Debris flows are among the most common geological disasters in China,and have been particularly frequent in Sichuan Province since the Wenchuan earthquake on 12 May 2008.The construction of debris flow drainage channels is a countermeasure used to distribute debris flow fans,and these channels play a critical role in the mitigation and prevention of damage resulting from debris flows.Under field conditions,the useful life of drainage channels can be greatly shortened as a result of strong abrasions to the drainage structure caused by the debris flow.Field investigations have shown that the types of damage to drainage channels include(a) erosion caused by hyper-concentrated silt flow,(b) impact fractures and foundation scour at the groundsills of the drainage channel,(c) destruction of the drainage channel outlet,and(d) destruction of the drainage channel caused by debris flow abrasion.In addition,based on the destruction of the drainage channel during the debris flow drainage process,a new type of drainage channel with energy dissipation components was proposed and applied in a steep,narrow gully for debris flow mitigation.Moreover,design and engineering repair recommendations for drainage channels are provided as a reference for repairing the damage to the channel.The results can provide an important reference for the effective repair and optimal design of drainage channels.

Calcium signaling and T-type calcium channels in cancer cell cycling

Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.

Inhibitory actions of mibefradil on steroidogenesis in mouse Leydig cells： involvement of Ca^2＋ entry via the T-type Ca^2＋ channel

Intracellular cAMP and Ca^2＋ are involved in the regulation of steroidogenic activity in Leydig cells, which coordinate responses to luteinizing hormone （LH） and human ehorionic gonadotropin （hCG）. However, the identification of Ca^2＋ entry implicated in Leydig cell steroidogenesis is not well defined. The objective of this study was to identify the type of Ca^2＋ channel that affects Leydig cell steroidogenesis. In vitro steroidogenesis in the freshly dissociated Leydig cells of mice was induced by hCG incubation. The effects of mibefradil （a putative T-type Ca^2＋ channel blocker） on steroidogenesis were assessed using reverse transcription （RT）-polymerase chain reaction analysis for the steroidogenic acute regulatory protein （STAR） mRNA expression and testosterone production using radioimmunoassay. In the presence of 1.0 mmol L-1 extracellular Ca^2＋, hCG at 1 to 100 IU noticeably elevated both StAR mRNA level and testosterone secretion （P 〈 0.05）, and the stimulatory effects of hCG were markedly diminished by mibefradil in a dose-dependent manner （P 〈 0.05）. Moreover; the hCG-induced increase in testosterone production was completely removed when external Ca^2＋ was omitted, implying that Ca entry is needed for hCG-induced steroidogenesis. Furthermore, a patch-clamp study revealed the presence of mibefradil-sensitive Ca^24- currents seen at a concentration range that nearly paralleled those inhibiting steroidogenesis. Collectively, Our data provide evidence that hCG-stimulated steroidogenesis is mediated at least in part by Ca^2＋ entry carried out by the T-type Ca^2＋ channel in the Leydig cells of mice.

Groove-type channel enhancement-mode Al GaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures

A novel groove-type channel enhancement-mode AlGaN/GaN MIS high electron mobility transistor（GTCE-HEMT）with a combined polar and nonpolar AlGaN/GaN heterostucture is presented. The device simulation shows a threshold voltage of 1.24 V, peak transconductance of 182 m S/mm, and subthreshold slope of 85 m V/dec, which are obtained by adjusting the device parameters. Interestingly, it is possible to control the threshold voltage accurately without precisely controlling the etching depth in fabrication by adopting this structure. Besides, the breakdown voltage（VB） is significantly increased by 78% in comparison with the value of the conventional MIS-HEMT. Moreover, the fabrication process of the novel device is entirely compatible with that of the conventional depletion-mode（D-mode） polar AlGaN/GaN HEMT. It presents a promising way to realize the switch application and the E/D-mode logic circuits.

NUMERICAL SIMULATION OF ATTENUATION OF LOVE-TYPE CHANNEL WAVES IN VISCOELASTIC MEDIA

Proceeding from wave equations, the paper strictly deduced the dispersion relation equation of Love-type channel waves in Standard Linear Solid model. The e quation is a complex one with its real part signifying the dispersion characteristics of the channel wave while the imaginary part, the attenuation characteristics. In calcu lating the attenuation value, the author has set up a mathematical model of a horizon tal symmetric sequence (a three layer sequence of rock-coal-rock), given out some physical parametersl and adopted the dichotomy method that is more of ten used in root resolving of an equatlon. The calculation indicates that the influence of non-elas tic absorption on the attenuation of the propagation of channel wave varies with the frequency. In the frequency band of the Airy phase, the attenuation increases steep like, which is unfavorable for the channel wave seismic prospecting. The study of channel wave attenuation has provided a theoretical basis for the compensation of at tenuation.

Effects of Tiaomaiyin and Its Disassembled Prescription on Expression of L-type Calcium Channel β2 Subunit in Rat Model of Tachyarrhythmia

[Objectives] To study the effects of Tiaomaiyin and its disassembled prescription on expression of L-type calcium channel β2 subunit in rat model of tachyarrhythmia. [Methods] Sixty Wistar rats were randomly divided into model group,Tiaomaiyin prescription group( whole prescription group),main efficacy group of removing heat to cool blood( blood cooling group),and auxiliary drug efficacy group of benefiting qi and nourishing heart( qi benefiting group),auxiliary efficacy group of promoting flow of qi and blood circulation( qi flow promoting group),and amiodarone group( western medicine group). Aconitine was given 7 d after the intragastric administration of the corresponding drugs,and the time of occurrence of arrhythmia in each group was observed. The left ventricular myocardium was subjected to reverse transcription-polymerase chain reaction and Western blotting. [Results] The ventricular premature beats( VPB) time in the whole prescription group and western medicine group was significantly longer than that in the model group. Ventricular tachycardia( VT),ventricular fibrillation( VF),and cardiac arrest( CA) were longer in the whole prescription group,blood cooling group,and western medicine group. The mRNA and protein expression of L-type calcium channel β2 subunit in the whole prescription group,blood cooling group and western medicine group were significantly decreased. [Conclusions] Tiaomaiyin whole prescription group and blood cooling group can reduce the occurrence time of tachyarrhythmia and reduce the expression of LTCC β2 in myocardium.

T-type calcium channel expression in cultured human neuroblastoma cells

Human neuroblastoma cells （SH-SY5Y） have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type calcium channels in SH-SY5Y cells.However,the distribution of the low-voltage activated calcium channel （namely called T-type calcium channel,including Cav3.1,Cav3.2,and Cav3.3） in SH-SY5Y cells remains poorly understood.The present study detected mRNA and protein expres-sion of the T-type calcium channel （Cav3.1,Cav3.2,and Cav3.3） in cultured SH-SY5Y cells using real-time polymerase chain reaction （PCR） and western blot analysis.Results revealed mRNA and protein expression from all three T-type calcium channel subtypes in SH-SY5Y cells.Moreover,Cav3.1 was the predominant T-type calcium channel subtype in SH-SY5Y cells.

Antiepileptic Drug-Induced Apoptosis Was Prevented by L-Type Calcium Channel Activator in Cultured Rat Cortical Cells

Experimental data have shown that antiepileptic drugs cause neurodegeneration in developing rats. Valproate (VPA) is the drug of choice in primary generalized epilepsies, and carbamazepine (CBZ) is one of the most prescribed drugs in partial seizures. These drugs block sodium channels, thereby reducing sustained repetitive neuronal firing. The intracellular mechanisms whereby AEDs induce neuronal cell death are unclear. We examined whether AEDs induce apoptotic cell death in cultured cortical cells and whether calcium ions are involved in the AED-induced cell death. VPA and CBZ increased apoptotic cell death and induced morphological changes that were characterized by cell shrinkage and nuclear condensation or fragmentation. Incubation of cortical cultures with VPA or CBZ decreased phospho-Akt levels. CBZ decreased the intracellular calcium levels. On the other hand, FPL64176, an L-type calcium channel activator, increased the intracellular calcium levels and prevented the AED-induced apoptosis. Glycogen synthase kinase-3 inhibitors, such as alsterpaullone and azakenpaullone, prevented the AED-induced apoptosis. These results suggest that intracellular calcium level changes are associated with AEDs and apoptosis and that the activation of glycogen synthase kinase-3 is involved in the death of rat cortical neurons.

Dispersion of Dynamic Biochemical Signals in Steady Flow in a Shallow Y-type Microfluidic Channel

This paper presents an analysis of dispersion of dynamic biochemical signals in steady flow in a shallow Y-type microfluidic channel. A method is presented to control the flow widths of two steady flows in the Y-type microchannel from two inlets.The transfer function for the Y-type microchannel is given by solving the governing equation for the Taylor-Aris dispersion in the microchannel. The amplitude-frequency and phase-frequency relations are provided which show that a shallow Y-type microchannel acts as a low-pass filter. The transports of different dynamic biochemical signals are investigated. In comparison with a fully mixing microfluidic channel, the magnitudes of the dynamic signals at the outlets in a Y-type microchannel are much smaller than those in a fully mixing microchannel, which demonstrates that the amplitude attenuation in a Y-type microchannel is larger than that of a fully mixing microchannel due to the transverse molecular diffusion. In order to control the desired signal in a microchannel, the solution of the inverse problem for the channel is also presented.

深厚冲积层薄基岩条件下沿空留巷支护技术研究

为解决某矿16041工作面原支护方案沿空留巷变形大、破坏严重难题,提出了顶板采用“16#槽钢梁+注浆锚索”、采空区侧采用“36U型钢+注浆锚杆”不对称耦合支护优化方案,基于理论分析研究围岩结构破坏形式,通过单元荷载法计算了留巷顶板与采空区侧围岩应力,最后开展工业性应用,验证优化后方案的合理性。研究表明:优化后支护方案顶板和采空区侧计算单元面荷载分别为351.85 kPa和206.53 kPa;注浆锚索和注浆锚杆承载力分别为263.89 kN和199.08 kN,均小于注浆锚索(锚杆)极限承载力。根据对留巷数据监测,最大顶板下沉量为35.6 mm,较原支护方案减小了1.40倍;采空区侧最大移近量为29.6 mm,与较原支护方案减小了4.13倍;最大注浆锚索承载力为253 kN,与理论计算值误差为4.1%;最大注浆锚杆承载力为174 kN,与理论计算值误差为12.6%。位移量与支护承载力均在工程允许范围内,优化后方案支护效果良好。

河道型水库沉积物有机碳空间分布特征及其埋藏效应

【目的】河流筑坝对有机碳具有重要的拦截作用,影响内陆水体碳循环。目前,河道型水库沉积物有机碳空间分布特征和自生有机碳埋藏通量仍不明确。【方法】采用沉积物柱芯法、沉积物物理化学参数和碳同位素二元混合模型,对河道型水库(银盘水库)沉积物有机碳埋藏开展了调研。【结果】结果显示:银盘水库沉积物有机碳含量变化范围为0.99%~1.32%,库中和坝前沉积柱有机碳含量均值分别为1.12%和1.16%;内源有机碳与总磷呈现显著正相关;有机碳埋藏速率变化范围为98.7~348.9 g C·m^(-2)·a^(-1),平均值为223.8 g C·m^(-2)·a^(-1),有机碳埋藏通量和内源有机碳埋藏通量分别为2.5×10^(9)g C·a^(-1)和1.8×10^(9)g C·a^(-1);内源有机碳对沉积物总有机碳的贡献比例为69.0%~75.2%,平均值为71.5%。【结论】结果表明:河道型水库沉积柱有机碳含量从库中到坝前没有明显变化;水库内源有机质的生成与营养盐输入和水体滞留时间密切相关;银盘水库有机碳埋藏通量相当于全球水库有机碳埋藏通量的0.04‰,河道型水库是个重要的潜在碳汇。研究结果能够为河道型水库碳埋藏研究和水电清洁型评估提供参考依据。

Effects of Intrathecally Administerd NaV1.8 Antisense Oligonucleotide on the Expression of Sodium Channel mRNA in Dorsal Root Ganglion

Neuropathic pain has been hypothesized to be the result of aberrant expression and function of sodium channels at the site of injury. To investigate the effects of NaV1.8 antisense oligonucleotide on the expression of sodium channel mRNA in dorsal root ganglion （DRG） neurons in chronic neuropathic pain. 24 Sprague-Dawley rats weighing 200--260 g were anesthetized with the intraperitoneal injection of 300 mg· kg^-1 choral hydrate. The CCI model was made by loose ligation of sciatic nerve trunk by 4--0 chromic gut. The mechanical and thermal pain threshold were measured before operation and 1, 3, 5, 7, 9, 11, 13 days after operation. A PE-10 catheter was implanted in subarachnoid space at lumbar region. On the 7th postoperative day the animals were randomly divided into 4 groups. The drugs were injected intrathecally twice a day for 5 consecutive days in group 2--4. The animals were decapitated 14 days after the surgery. The L4--L6 DRG of the operated side was removed and crushed, and total RNA was extracted with Trizol reagent. The contralateral side was used as control. The change of NaV1.8 sodium channel transcripts was determined by RT-PCR. Pain threshold was significantly lowered after CCI as compared with that in control group and was elevated 3 days after antisense oligonucleotide injection. Sensory neuron specific TTX-R sodium channel NaV1.8 transcript was down-regulated after antisense oligonucleotide injection at the dosage of 45 μg as compared with that in CCI group （P〈0.01）, and it was even greater at the dosage of 90 μg. The intrathecally injected NaV1.8 antisense oligonucleotide can reduce the mechanical allodynia and thermal hyperalgesia partially by downregulating the SNS transcript expression.

分散梯级船闸输水时的作用水头和中间渠道断面形式对通航水流条件的影响

针对分散梯级船闸中间渠道的通航水流条件问题,研究了中间渠道断面形式对其影响。提出了矩形断面与梯形断面中间渠道的作用水头计算公式。采用数学数值模拟的方法研究两种断面形状对船闸通航水流条件的影响。结果表明:1)中间渠道充泄水的船闸作用水头一致,其水位呈现周期性的变化。2)改变中间渠道的断面形式对船闸输水时的流量变化趋势与输水时间影响较小。3)相较于矩形断面,梯形断面的中间渠道可以有效地减小上游船闸泄水过程中的水位变幅、振荡波波高、最大水面坡降和最大纵向流速。研究为分散梯级船闸中间渠道的设计提供了理论支持。

基于经验小波变换的多通道微弱电流信号噪声控制

多通道微弱电流信号受很多噪声因素的干扰,导致输出的微弱电流信号与原始信号之间的相对误差增加,控制效果变差,为此提出基于经验小波变换的多通道微弱电流信号噪声控制方法;采集多通道微弱电流信号,利用经验小波变换技术分解采集到的微弱电流信号,判断电流信号中是否存在噪声并确定噪声类型;设计微弱电流信号噪声控制器,根据电流信号中的噪声量与噪声类型生成控制指令,对不同通道微弱电流信号噪声进行控制;在两种不同噪声强度的实验环境下,该方法控制下的多通道微弱电流信号信噪比较高,输出信号与原始信号间的相对误差较低,控制任务完成时间更短;以此证明该方法的多通道微弱电流信号噪声控制效果更好,可以广泛应用至电流信号噪声控制领域。

东海西湖凹陷C油田花港组H3沉积微相研究

研究区C油田位于东海西湖凹陷中央背斜带南部,主力产层为渐新统花港组H3碎屑岩储层。H3储层砂体横向迁移摆动频繁,垂向多期次叠加,沉积微相及展布规律认识不清。针对海上井资料少、地质特征复杂的特点,综合应用研究区岩心、测井、地震数据及实验室分析数据等相关资料,明确目的层相标志、微相类型,分析了东海西湖凹陷C油田H3沉积微相平面展布及纵向演化特征。研究结果表明本区发育浅水辫状河三角洲前缘亚相,发育水下分流河道、支流间湾微相,水下分流河道进一步细分为主水道、次级水道及水道边缘,其中主水道是本区有利相带,呈条带状分布为主,复合砂体内部连通性较差,开发中后期往往易形成剩余油富集区;水下分流河道末端多发育孤立型储层,砂体规模较小,与沟源断层搭接可形成向上倾方向尖灭的构造-岩性复合油气藏。该研究明确有利沉积相带与油气分布的关系,对本地区及其它地区调整井的部署具有重要的指导意义。

分体式门形满堂架施工技术

为解决在隧洞进口段施工过程中满堂脚手架长时间阻断重要通道,影响正常施工,可将满堂脚手架进行分体式搭设方式缩短通道占用时间。在模板铺设及钢管绑扎备仓阶段荷载较小,可采取搭设门洞型脚手架支撑体系方式,保障设备及人员通行,最后在浇筑前将预留的门洞采用钢管脚手架连接支撑加固形成最终满堂脚手架支撑体系,避免了备仓及后续养护阶段对通道的长时间占用。

山地城市雨源型河道水环境综合治理对策及措施探讨

重庆市溉澜溪属于长江一级支流,是典型的山地雨源型河道,以往多次整改效果却不明显。本工程以溉澜溪河道实现准Ⅳ类(除TN外,其他均达到Ⅳ类)水质为工程目标,本底调研掌握管涵的水质、水量,针对河道容量小、自净能力弱、源头雨污分流不彻底、地下水丰富且污染程度重、底泥淤积量大等问题,系统治理方案采用源头控源截污+末端处理治理技术,源头雨污分流改造降低污染负荷,末端再修建水质站处理剩余污水,并实现河道补水功能。在河道起点提标改造现状新华水质站工艺,出水满足河道日常生态补水需要,末端新建溉澜溪水质提升站处理剩余污水,具备雨后河道水质快速更新的功能,两座水质站出水水质满足准Ⅳ类标准,通过在线监测流量数据用以预测水质处理站规模在行业内具有创新意义。通过治理溉澜溪河道已彻底消除黑臭,重现清水绿岸、鱼翔浅底的美丽景象。

大果木姜子油调控miR-328基因抗心律失常H9c2细胞的机制研究

目的:探讨大果木姜子油通过调控miR-328基因抗心律失常H9c2细胞的可能机制。方法:慢病毒转染构建miR-328过表达H9c2细胞株,再运用生物机能实验系统构建H9c2细胞和miR-328过表达H9c2细胞心律失常模型。将H9c2细胞分为正常对照组、模型组、大果木姜子油组、miR-328过表达组和miR-328过表达+大果木姜子油组。根据分组条件培养结束后,qPCR检测H9c2细胞中miR-328相对表达量;ELISA检测炎性因子IL-1β、IL-6、TGF-β含量;比色法检测SOD活性和MDA浓度;DCFH荧光探针检测ROS水平;流式细胞术检测细胞凋亡率;Western Blot检测H9c2细胞L型钙通道相关蛋白表达。结果:成功构建H9c2细胞和miR-328过表达H9c2细胞心律失常模型。与正常对照组比较,模型组和miR-328过表达组细胞TGF-β、SOD活性及CaM、CaMKⅡ、p-CaMKⅡ蛋白表达显著降低,细胞凋亡率、miR-328及CaV1.2蛋白表达和IL-1β、IL-6、MDA、ROS水平显著升高(P<0.01)。经大果木姜子油干预后,心律失常模型细胞形态改善,上述指标均被显著逆转(P<0.01)。结论:大果木姜子油可改善心律失常H9c2细胞,其作用机制可能与调控miR-328基因降低炎症因子水平、调节氧化应激、抑制细胞凋亡及调节L型钙通道相关蛋白表达有关。