Addition of human melanopsin renders mammalian cells photoresponsive

A small number of mammalian retinal ganglion cells act as photoreceptors for regulating certain non-image forming photoresponses. These intrinsically photosensitive retinal ganglion cells express the putative photopigment melanopsin. Ablation of the melanopsin gene renders these cells insensitive to light; however, the precise role of melanopsin in supporting cellular photosensitivity is unconfirmed. Here we show that heterologous expression of human melanopsin in a mouse paraneuronal cell line (Neuro-2a) is sufficient to render these cells photoreceptive. Under such conditions, melanopsin acts as a sensory photopigment, coupled to a native ion channel via a G-protein signalling cascade, to drive physiological light detection. The melanopsin photoresponse relies on the presence of cis-isoforms of retinaldehyde and is selectively sensitive to short-wavelength light. We also present evidence to show that melanopsin functions as a bistable pigment in this system, having an intrinsic photoisomerase regeneration function that is chromatically shifted to longer wavelengths.     

Division and subtraction by distinct cortical inhibitory networks in vivo

Brain circuits process information through specialized neuronal subclasses interacting within a network. Revealing their interplay requires activating specific cells while monitoring others in a functioning circuit. Here we use a new platform for two-way light-based circuit interrogation in visual cortex in vivo to show the computational implications of modulating different subclasses of inhibitory neurons during sensory processing. We find that soma-targeting, parvalbumin-expressing (PV) neurons principally divide responses but preserve stimulus selectivity, whereas dendrite-targeting, somatostatin-expressing (SOM) neurons principally subtract from excitatory responses and sharpen selectivity. Visualized in vivo cell-attached recordings show that division by PV neurons alters response gain, whereas subtraction by SOM neurons shifts response levels. Finally, stimulating identified neurons while scanning many target cells reveals that single PV and SOM neurons functionally impact only specific subsets of neurons in their projection fields. These findings provide direct evidence that inhibitory neuronal subclasses have distinct and complementary roles in cortical computations.     

光学微分与光学相减

提出了光学微分的新方法,离焦像与准确像之间得到二阶光学微分,并分别对强度微分及振幅微分作了讨论。     

Boolean代数与减法代数

根据集合代数的研究引入了减法代数的概念．证明了任一Ｂｏｏｌｅａｎ代数等价于一个具有一个二元代数运算，且仅可由四个方程式定义的减法代数系统〈Ｘ；－，０，１〉     

河南蓼属(Polygonum Linn.)增补与订正

报道了《河南植物志》中未记录的河南产蓼属植物2种1变种,其中长箭叶蓼(Polygonum hastato-sagittatum Mak.）为河南分布新记录,订正了一些分类群的学名。     

超声辐射下氢氧化钾催化的Michael加成(英文)

超声辐射下 ,查耳酮与含有活泼亚甲基的化合物诸如硝基甲烷、丙二酸二乙酯和乙酰乙酸乙酯等 ,在氢氧化钾催化下进行Michael加成 ,产品收率为 75 %～ 98% .该法具有反应时间短 ,产率高的优点     

Social evaluation by preverbal infants

The capacity to evaluate other people is essential for navigating the social world. Humans must be able to assess the actions and intentions of the people around them, and make accurate decisions about who is friend and who is foe, who is an appropriate social partner and who is not. Indeed, all social animals benefit from the capacity to identify individual conspecifics that may help them, and to distinguish these individuals from others that may harm them. Human adults evaluate people rapidly and automatically on the basis of both behaviour and physical features, but the ontogenetic origins and development of this capacity are not well understood. Here we show that 6- and 10-month-old infants take into account an individual's actions towards others in evaluating that individual as appealing or aversive: infants prefer an individual who helps another to one who hinders another, prefer a helping individual to a neutral individual, and prefer a neutral individual to a hindering individual. These findings constitute evidence that preverbal infants assess individuals on the basis of their behaviour towards others. This capacity may serve as the foundation for moral thought and action, and its early developmental emergence supports the view that social evaluation is a biological adaptation.     

试样加入法-离子选择性电极测定氟

建立了一种离子选择性电极法测定高浓度氟的新方法.该方法在体积为100.0 ml、浓度为1.000×10-4 mol/l的标准溶液中加入1.000 ml高浓度试样,加入前后测定其电动势,由这两个电动势和溶液体积计算试样的含氟量.10次测定的标准偏差S小于0.004,相对标准偏差RSD小于4%,3个水平、6次测定的回收率在95.0%～101%之间.     

试样加入法-离子选择性电极测定氟

建立了一种离子选择性电极法测定高浓度氟的新方法.该方法在体积为100.0 ml、浓度为1.000×10-4 mol/l的标准溶液中加入1.000 ml高浓度试样,加入前后测定其电动势,由这两个电动势和溶液体积计算试样的含氟量.10次测定的标准偏差S小于0.004,相对标准偏差RSD小于4%,3个水平、6次测定的回收率在95.0%～101%之间.     

硫醇催化的醛类化合物加成至烯酰胺类化合物的自由基链反应(英文)

伯醛化合物加成在富电子碳碳双键的自由基链反应可以通过硫醇的催化作用来实现,硫醇的作用表现为一个极性可逆的催化剂,它可以促使氢原子从醛完全转移至加成自由基上,该自由基是载链酰基自由基加成至烯酰胺上所生成的     

标准加入——火焰原子吸收法测定痕量银的研究

研究了标准加入--火焰原子吸收法测定痕量银的方法.该方法无需分离,简便、快速,干扰少,用于实际样品的测定,结果满意.     

脱铝USY分子筛催化α—蒎烯与乙醇加成反应的研究

用FTIR、XRD和SEM等现代测试技术表征了用盐酸抽提USY脱铝制得的一系列DUSY催化剂的结构。发现在盐酸与USY反应中既溶掉了无定形的铝化合物也脱去了骨架铝。提高了骨架SiO2／Al2O3，使晶胞缩小、特征振动增强，但对晶粒大小和形貌影响不大。吡啶吸附后的红外测试表明，DUSY催化剂表面上的酸中心主要是B酸，只有少量的L酸。在α-蒎烯与乙醇加成反应中，DUSY的活性远高于USY，生成α-松油基醚的选择性也比USY好。     

K比例H点标准加入法同时测定锌与镉

锌与镉化学性质相似,常常共存于同一试样中,与试剂 4- (2-吡啶偶氮 )间苯二酚(PAR)发生显色反应,其吸收光谱相互重叠.用K比例H点标准加入法结合分光光度法对该混合体系进行了研究,建立了不经分离,同时测定锌、镉的方法,结果满意.     

K比例H点标准加入法同时测定硝酸根和亚硝酸根

研究了在近中性介质中,硝酸根与亚硝酸根的紫外吸收光谱,提出了引用"K比例H点标准加入法"同时测定了硝酸根、亚硝酸根含量的方法.并测定了合成水样及环境水样中硝酸根和亚硝酸根含量,结果满意.     

标准加入法测定有机制剂中铁含量

目的:标准加入分光光度法测定铁叶绿酸钠中铁离子含量.方法:在一定pH条件下,使铁离子从铁叶绿酸钠卟啉环中解离出来,标准加入法测定Fe2+与邻菲罗啉络合物的吸光度.结果:此法测定Fe2+含量平均回收率为97.84%,RSD≤0.75%(n=5),分析速度快.结论:方法操作简便、环保,适用于有机铁制剂生产的质量控制,叶绿素铁衍生物盐及其制剂含量的测定.     

投加粉末活性炭强化好氧颗粒污泥的稳定性

好氧颗粒污泥系统稳定运行一段时间后,往往会发生颗粒污泥解体现象,系统内水力选择压与基质选择压之间的平衡失调,是导致颗粒污泥解体、系统失调的内在诱因.采用了投加粉末活性炭(PAC)强化好氧颗粒污泥稳定性的调控措施.结果发现,PAC的投加对污泥物理性状及微生物生长动力学方面影响明显:投加PAC可以强化系统内水力选择压,提高污泥的湿密度和强度,降低污泥生长速率和产率,调节污泥浓度和粒径大小,降低粒径分布分散化的趋势,避免因传质阻力引起的颗粒内部分裂,保证好氧颗粒污泥系统持久维持稳定.PAC的投加对污泥化学性状影响甚微:不管投加PAC污泥与否,在颗粒污泥形成过程中均伴随着胞外蛋白浓度的增加及污泥表面相对疏水性的上升.     

多次标准加入法测定样品中的微量氟

利用多次标准加入法,在pH5.0～6.0的缓冲体系中进行了样品中微量氟的测定.研究了测试体系中总离子强度调节缓冲溶液(TISAB)的组成和用量,以及空白电位的快速恢复方法.结果表明:用柠檬酸、醋酸、氯化钠组成TISAB,加入量为溶液总量的10%～20%,测定效果最佳.利用此法测量了水、食盐、牙膏、面粉、啤酒等样品中的氟含量,方法回收率为97.0%～103.0%,5次平行样品测定结果的相对标准偏差均不大于2%.本法操作简单、快速、准确,可用于微量氟的测定.     

关于烯烃的亲电加成反应机理与立体选择性

烯烃的亲电加成反应机理一般认为有两种可能历程。一种是通过生成环状正离子中间体进行的,通过这样的历程进行的加成反应是反式加成。另一种是通过碳正离子中间体进行的,它所得到的产物无立体选择性。     

十六烷基三甲基溴化铵强化产氢发酵

微生物发酵产生的生物气要经过细胞膜释放出去,产氢菌胞外膜的通透性影响产氢发酵过程。本文研究了十六烷基三甲基溴化铵(CTAB)对混合菌胞外膜通透性和厌氧产氢发酵过程的影响。研究结果表明:浓度大于0.009 5 g/L的CTAB可有效提高混合菌胞外膜的通透性;浓度小于0.045 0 g/L时,CTAB对发酵终端的生物量和pH无明显影响;在0.009 5⁰.027 0 g/L的CTAB条件下,发酵体系的产氢速率和累计产氢量随着CTAB浓度的增加而增加;在0.027 0 g/L的CTAB条件下,获得最大产氢速率19.6 mL/h和最大产氢效率13.6 mmol每克木糖,分别较未添加CTAB时提高44%和38%;在0.045 0 g/L的CTAB条件下,混合菌产氢能力受到明显抑制。这些研究结果表明:合适浓度的CTAB可以作为一种高效的生物活化剂用于强化厌氧产氢发酵。