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1.
复合增聚型铁铝无机高分子絮凝剂PAFCS的红外光谱研究   总被引:13,自引:0,他引:13  
利用煤矸石及硫铁矿渣制备出了一种新型无机高分子絮凝剂聚硫酸氯化铁铝(PAFCS),研究了PAFCS的红外(IR)光谱结构特征.IR谱分析表明PAFCS是Fe(Ⅲ)十Al(Ⅲ)与羟基(-OH)以双羟桥为主结构连接的较复杂的高聚物.其IR图谱峰形与α-Fe2O3,α-FeOOH及Fe(OH)3等明显不同.比较了PAFCS,PAC,PFS,PACS的光谱特征,表明PAFCS与已知文献报道的絮凝剂PAC,PFS,PACS有类似性,即由3100~3600cm(-1)处的OH伸缩振动及1600~1650cm(-1)H-O-H弯曲振动的畸变,表明有结构羟基存在;在1100cm(-1)附近M-OH-M伸缩振动峰为中等强度峰,证明有铁羟基或铝羟基以及聚合态存在.  相似文献   

2.
该文主要以色谱技术研究了负载型Ni(Ac)_2的热分解性能。结果表明,Ni(Ac)_2的分解过程取决于载体的性质。强酸性载体HZSM-5分子筛起催化分解作用,导致Ni(Ac)_2分解时在低温区出现CH_4和CO_2峰;MgO与Ni(Ac)_2的配位作用致使Ni(Ac)_2有两个最佳分解温度,CO_2,CO和H_2相应地都出现两个峰;与MgO和HZSM-5相比,SiO_2和γ-A1_2O_3对Ni(AC)_2热分解的影响不很明显。但SO_2,γ-A1_2O_3和HZSM-5有较强的甲烷化效应。  相似文献   

3.
等点时Cu(Ⅱ)与HSA与BSA结合的研究   总被引:2,自引:1,他引:1  
用平衡透析法研究了等电点时Cu(Ⅱ)与人血清白蛋白(HSA)或牛血清白蛋白的相互作用,Scatchard图分析表明,HSA和BSA对Cu(Ⅱ)各有1个强结合部位,它可能位于白蛋白分子的N-端三肽段上,为全面反映Cu(Ⅱ)与HSA或BSA的结合情况,用非线性最小二乘法拟合Bjerrum方程,首次报道了等电点时Cu(Ⅱ)-HSA和Cu(Ⅱ)-BSA体系的逐级稳定常数值,其K1的数量级为10^4.Hil  相似文献   

4.
采用元素分析、X射线光电子谱(XPS)以及直流电导率σdc(T)与温度关系等方法对三种聚苯胺PANI-HCl,PANI-H2SO4和PANI-H3PO4进行了研究.在Cl(2p)谱中,可以分辨四个二重态的自旋轨道裂分偶极子Cl(2p1/2)和Cl(2p3/2).S(2p)-core-level谱显示了二重态自旋轨道的裂分偶极子S(2p1/2)和S(2p3/2),而P(2p)-core-level谱仅在结合能为134.03eV时显示单一的峰值.室温时PANI-HCl和PANI-H2SO4的σdc比PANI-H3PO4的σdc高数倍.PANI样品的导电性与温度的关系表明它们是半导体,而且符合准一维的变程跳跃(Q1D-VRH)模型  相似文献   

5.
捕食线虫真菌自发产生捕食器官的菌株筛选   总被引:1,自引:0,他引:1  
在Czapek,PDA,CMA,WA四种培养基上,从21株捕食线虫真菌中筛选到7株在无线虫诱导条件下能自发形成捕食器官的真菌,这些菌株是:J8-1(Arthrobotrys lligospora var.oligospora),MW17-2(A.javanica),J31-1(A.vermicola),J34-1(Dactylella leptospora),XZ9-2,XS2-2,O1-1(A.  相似文献   

6.
不同酸掺杂对聚苯胺导电性能的影响   总被引:1,自引:0,他引:1  
采用元素分析,X射线光电子谱(XPS),以及直流电导率σdc(T)与温度关系等方法对三种聚苯胺PANI-HCl,PANI-H2SO4和PANI-H3PO4进行了研究,在Cl(2p)谱中,可以分辨四个二重态的自旋轨道裂分偶极子Cl(2p1/2)和Cl(2p2/2)S(2p)-core-level谱显示了二重态自旋轨道的裂分偶极子S(2p1/2)和S(2p3/2),而P(2p)-core-level,  相似文献   

7.
研究了以丙烯酸、月桂醇为原料制备食品级抗氧化剂硫代二丙酸二月桂酯(DLTP)的方法和DLTP对食用油脂抗氧化效能的评价,实验结果表明:丙烯酸法合成DLTP,其主要影响因素是制备中间体硫代二丙酸的反应物配比、回流温度和回流时间等因素,实验的最佳方案是c(NaOH):c(Na2S):c(CH2=CHCOOH)=1.2:1.1:2.0,回流温度为107℃,回流时间为2.5h;制得的DLTP基本符合食品级  相似文献   

8.
本文利用正交理论,以Al-CAS-CTMAB为体系,对常用的单因素变化法所选择的最佳显色条件进行比较。结果表明,在采用正交设计法选择出的最优条件下,Al-CAS-CTMAB体系的摩尔吸光系数可达2.4×10 ̄(-5)L·mol ̄(-1)·cm ̄(-1),比常规单因素变化法提高2.4倍。  相似文献   

9.
用LDF-LMTO-ASA超原胞法,以Nb(C_(1-x)□_x)为例直接计算Nb_4C_4□_0、Nb_4C_3□_1、Nb_4C_2□_2、Nb_4C_1□3和Nb_4C_□_4五种“样本”在不同晶格常数下的总能的变化,结合统计分布直接计算碳空位在非金属元素的f,c,c子晶格上分布有序的稳定性,计算结果表明NaCl型Nb(C_(1-x)□_x)的有序相和无序相仅在0<x<0.5组分范围内存在,其中有序相更稳定。x>0.5时不存在上述结构的有序或无序相。这与实验结果一致。  相似文献   

10.
带有单纯疱疹病毒脱氧胸苷激酶基因(HSV-tk)的腺病毒结合ganciclovir(GCV)对分裂细胞有很强的杀伤作用.在感染复数(M.O.I,MultiPlicityofInfection)达到1000时对人体肺腺癌细胞A549的杀伤几乎达到100%.四种人体肺癌细胞株(A549,LAX,SPC,SKY)对带HSV-tk的腺病毒(ADV/RSV-tk)的杀伤作用表现出不同的敏感性.另Acyclovir(ACV)和GCV对感染了重组腺病毒ADV/RSV-tk的细胞都有一定杀伤作用,但杀伤效果有很大差别;就A549而言,GCV的杀伤作用比ACV高7~8倍.此外ADV/RSV-tk结合GCV杀伤肿瘤细胞时有“旁观者效应”,即感染了ADV/RSV-tk的细胞与未感染细胞混合后,后者也明显地遭到杀伤.  相似文献   

11.
应用电生理学技术结合行为学方法,探查了大鼠在明暗分辨学习后额叶皮层的突触效能变化,结果表明:多数动物(64.7%)出现突触传递效能的增强变化,少数(11.8%)出现降低变化或不明显变化(23.5%);并且,学习后检测到的突触效能增强变化还可随行为作业的迅速变更而相应改变,即随行为的消退而恢复,又随行为的再学习而再次出现增强变化,本文并就结果予以讨论。  相似文献   

12.
血清CA125检测在卵巢癌复发中的临床意义   总被引:1,自引:0,他引:1  
总结和回顾了血清CA125检测在卵巢癌复发中临床应用以来的研究概况和主要成果,并分析了CA125检测在预测卵巢癌复发中存在的问题.  相似文献   

13.
14.
远志皂苷对小鼠行为习得及海马CA3区突触形态的影响   总被引:1,自引:0,他引:1  
为了探讨远志皂苷对小鼠学习能力及海马CA3区突触形态的影响,把30只小鼠随机分为2组:药物组灌胃生药量为4.50 g/kg的远志皂苷溶液,对照组灌胃相等剂量的生理盐水,14 d后进行行为学训练,期间继续给药10 d.训练结束后,各取7只小鼠检测海马CA3区突触密度、活性带长度、突触间隙宽度、PSD厚度及穿孔突触的比例....  相似文献   

15.
R Malinow  J P Miller 《Nature》1986,320(6062):529-530
Activity-induced changes in the efficacy of synaptic transmission between neurones are central to several prominent theories of learning. In both in vivo and in vitro preparations of the hippocampus, a conditioning high-frequency stimulus delivered to afferent fibres results in a long-term potentiation of synaptic transmission at those inputs. Evidence has been provided supporting both presynaptic and postsynaptic sites as loci where critical events occur in the development of potentiation. In this study we report that long-term potentiation is reversibly blocked by intracellular injection of hyperpolarizing current in the postsynaptic cell during the conditioning high-frequency stimulus, suggesting the involvement of a voltage-dependent postsynaptic mechanism.  相似文献   

16.
研究衰老大鼠的学习行为与海马内突触相关蛋白的表达.运用Y-迷宫方法对幼年对照组(断乳期)和老年期(22月龄)雄性Sprague—Dawley大鼠进行Y-迷宫空间学习记忆行为训练,之后利用免疫组化和Western blot方法检测2组大鼠海马内突触素(synaptophysin,Syn)、生长相关蛋白(GAP-43)的表达情况.研究结果:(1)2组相比,老年组的学习能力较强,幼年对照组记忆能力较强(P〈0.05);(2)生长相关蛋白GAP-43在老年组海马内的表达显著高于幼年对照组;而突触素的表达低于幼年对照组(P〈0.01).提示,GAP-43和突触素可能参与大鼠空间分辨学习记忆的过程,老年大鼠的中枢神经系统保持着潜在的神经元退化修复的功能.  相似文献   

17.
建立了N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺的注射液的HPLC的分析方法,在此基础上进行了N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺注射液的反复冻融影响因素试验。采用高效液相色谱法测定不同浓度的N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺样品,其拟合峰面积与N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺浓度呈良好线性。在N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺线性范围内计算反复冻融后N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺的含量,结果显示冻融前后其含量没有明显变化。结果表明,N-(2-甲氧基乙基)-2-(3-硝基-1,2,4,-三氮唑-1-)乙酰胺注射液反复冻融后含量及有关检验指标无明显变化,表明N-(2-甲氧基乙基)-2-(3-硝基-1,2, 4,-三氮唑-1-)乙酰胺注射液在反复冻融条件下稳定性良好。  相似文献   

18.
M Kano  U Rexhausen  J Dreessen  A Konnerth 《Nature》1992,356(6370):601-604
Persistent changes in synaptic efficacy are thought to underlie the formation of learning and memory in the brain. High-frequency activation of an afferent excitatory fibre system can induce long-term potentiation, and conjunctive activation of two distinct excitatory synaptic inputs to the cerebellar Purkinje cells can lead to long-term depression of the synaptic activity of one of the inputs. Here we report a new form of neural plasticity in which activation of an excitatory synaptic input can induce a potentiation of inhibitory synaptic signals to the same cell. In cerebellar Purkinje cells stimulation of the excitatory climbing fibre synapses is followed by a long-lasting (up to 75 min) potentiation of gamma-aminobutyric acid A (GABAA) receptor-mediated inhibitory postsynaptic currents (i.p.s.cs), a phenomenon that we term rebound potentiation. Using whole-cell patch-clamp recordings in combination with fluorometric video imaging of intracellular calcium ion concentration, we find that a climbing fibre-induced transient increase in postsynaptic calcium concentration triggers the induction of rebound potentiation. Because the response of Purkinje cells to bath-applied exogenous GABA is also potentiated after climbing fibre-stimulation with a time course similar to that of the rebound potentiation of i.p.s.cs, we conclude that the potentiation is caused by a calcium-dependent upregulation of postsynaptic GABAA receptor function. We propose that rebound potentiation is a mechanism by which in vivo block of climbing fibre activity induces an increase in excitability in Purkinje cells. Moreover, rebound potentiation of i.p.s.cs is a cellular mechanism which, in addition to the long-term depression of parallel fibre synaptic activity, may have an important role for motor learning in the cerebellum.  相似文献   

19.
Tye KM  Stuber GD  de Ridder B  Bonci A  Janak PH 《Nature》2008,453(7199):1253-1257
What neural changes underlie individual differences in goal-directed learning? The lateral amygdala (LA) is important for assigning emotional and motivational significance to discrete environmental cues, including those that signal rewarding events. Recognizing that a cue predicts a reward enhances an animal's ability to acquire that reward; however, the cellular and synaptic mechanisms that underlie cue-reward learning are unclear. Here we show that marked changes in both cue-induced neuronal firing and input-specific synaptic strength occur with the successful acquisition of a cue-reward association within a single training session. We performed both in vivo and ex vivo electrophysiological recordings in the LA of rats trained to self-administer sucrose. We observed that reward-learning success increased in proportion to the number of amygdala neurons that responded phasically to a reward-predictive cue. Furthermore, cue-reward learning induced an AMPA (alpha-amino-3-hydroxy-5-methyl-isoxazole propionic acid)-receptor-mediated increase in the strength of thalamic, but not cortical, synapses in the LA that was apparent immediately after the first training session. The level of learning attained by individual subjects was highly correlated with the degree of synaptic strength enhancement. Importantly, intra-LA NMDA (N-methyl-d-aspartate)-receptor blockade impaired reward-learning performance and attenuated the associated increase in synaptic strength. These findings provide evidence of a connection between LA synaptic plasticity and cue-reward learning, potentially representing a key mechanism underlying goal-directed behaviour.  相似文献   

20.
W C Abraham  G V Goddard 《Nature》1983,305(5936):717-719
All synaptically-based neuropsychological theories of learning postulate that there are changes resulting from neural activity which are long-lasting and confined to specific sets of synapses. In the past decade a form of synaptic strengthening known as long-term potentiation (LTP) has been found which results from high-frequency neural activity and is of sufficient duration to model as a learning mechanism. Some early tests of the synaptic specificity of LTP in area CA1 of the hippocampus indicated that although LTP was specific to the tetanized pathway, in a converging untetanized pathway it was associated with depression of synaptic transmission lasting for at least 30 min. However, others have found that this heterosynaptic depression more usually decays within 5-15 min post-tetanus despite the maintenance of LTP in the tetanized pathway. Similarly, in the dentate gyrus (DG), LTP of either the lateral (LPP) or medial (MPP) components of the perforant path afferents has been associated with only short-lasting reciprocal heterosynaptic depression. Here, using more detailed measurement of stimulus intensity curves, we report that tetanization of either MPP or LPP reliably depresses synaptic transmission in the other pathway for at least 3 h. This heterosynaptic depression, considerably smaller than the usual magnitude of LTP, was obtained regardless of whether LTP had been produced in the tetanized homosynaptic pathway. Heterosynaptic long-term depression was not observed if the test pathway had been previously tetanized.  相似文献   

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