荧光光谱滴定法测定痕量的双甲脒

通过荧光光谱滴定法研究了脱叔丁基杯[4]芳烃与双甲脒之间的相互作用。实验表明在加入不同量的双甲脒后脱叔丁基[4]芳烃的荧光发生猝灭,由此建立了一种快速简便的测定双甲脒的方法,该方法的线性范围是1.00～60.0μg/mL,添加回收试验表明该方法可行。     

Molecular recognition by self-assembled monolayers of cavitand receptors

It is shown by angle-resolved x-ray photoelectron spectroscopy that cavitands derived from resorcin[4]arenes provided with four dialkylsulfide chains form stable monolayers on gold surfaces that are well organized by self-assembly. The cavitand headgroups at the surface of the resorcin[4]arene monolayer act as molecular recognition sites for small organic molecules with remarkable selectivity for perchloroethylene (C(2)Cl(4)). Comparative thermal desorption experiments indicate binding sites with high interaction energies of C(2)Cl(4) at the surface of the resorcin[4]arene monolayers. Fast and reversible "host-guest" interactions were found by the monitoring of extremely small mass changes (in the nanogram range) with a quartz microbalance oscillator provided with gold electrodes coated by resorcin[4]arene monolayers.     

Evidence for coherent proton tunneling in a hydrogen bond network

We observed coherent proton tunneling in the cyclic network of four hydrogen bonds in calix[4]arene. The tunneling frequency of 35 megahertz was revealed by a peak in the magnetic field dependence of the proton spin-lattice relaxation rate measured with field-cycling nuclear magnetic resonance in the solid state at temperatures below 80 kelvin. The amplitude of the coherent tunneling peak grows with temperature according to a Boltzmann law with energy D/kB = (125 +/- 10) kelvin (where kB is Boltzmann's constant). The tunneling peak can be interpreted in the context of level crossings in the region where the tunneling frequency matches the proton Larmor frequency. The tunneling spectrum reveals fine structure that we attribute to coupling between the hydrogen bonds in the network. The characteristics of the tunneling peak are interpreted in the context of the potential energy surface experienced by the hydrogen atoms in the network.     

Storage of methane and freon by interstitial van der Waals confinement

A known host-guest assembly, organized only by means of relatively weak dispersive forces, exhibits hitherto unappreciated thermal stability. The hexagonal close-packed arrangement of calix[4]arene contains lattice voids that can occlude small, highly volatile molecules. This host-guest system can be exploited to retain a range of freons, as well as methane, not only well above their normal boiling points, but also at relatively high temperatures and low pressures. The usually overlooked van der Waals interactions in organic crystals can indeed be used in a highly stable supramolecular system for gas storage.     

新型主链杯[4]聚硅氧烷毛细管气相色谱固定相的研究

选用硅氢加成试剂(CH3)2SiHCl,合成了一种主链杯[4]芳烃二丁醚聚硅氧烷毛细管气相色谱固定相,考察了该固定相的色谱特性:柱效、极性、选择性和热稳定性,结果表明该杯[4]芳烃固定相具有良好的色谱性能。异物醇及十种芳香族位置异构体均得到良好分离。     

A

A solid state, electronically addressable, bistable [2]catenane-based molecular switching device was fabricated from a single monolayer of the [2]catenane, anchored with phospholipid counterions, and sandwiched between an n-type polycrystalline silicon bottom electrode and a metallic top electrode. The device exhibits hysteretic (bistable) current/voltage characteristics. The switch is opened at +2 volts, closed at -2 volts, and read at approximately 0.1 volt and may be recycled many times under ambient conditions. A mechanochemical mechanism for the action of the switch is presented and shown to be consistent with temperature-dependent measurements of the device operation.     

中药组方“回乳康”对回乳期奶牛血清E、P4和TGF-β1含量的影响

【目的】探究中药组方"回乳康"对回乳期奶牛血清雌激素(Estrogen,E)、孕酮(Progesterone,P4)和转化生长因子β1(Transforming growth factorβ1,TGF-β1)含量的影响。【方法】选取即将干乳日产奶量为(15.42±0.71)kg的健康奶牛80头,随机分为4组,每天饲喂0(对照组)、400、500和600 g"回乳康"中药,采用逐渐干奶法回乳,分别在回乳第0、1、3、5、7、9和11天采集奶牛尾静脉血,并记录奶牛单日产奶量,采用ELISA法检测血清E、P4和TGF-β1含量。【结果】0、400、500和600 g处理回乳时间分别为11、7、5和5 d;各组奶牛血清E含量在回乳期均随时间推移呈下降趋势,对照组下降趋势较中药组慢;对照组奶牛血清P4含量在回乳期变化不显著,而中药组奶牛血清P4含量均随时间推移呈上升趋势,在回乳期之后下降,但下降后仍极显著高于对照组;各处理回乳期奶牛血清TGF-β1含量均呈上升趋势,而在回乳期之后中药组奶牛血清TGF-β1含量呈下降趋势;回乳期奶牛血清E、TGF-β1含量和日产奶量两两间均呈极显著相关,血清P4含量与血清E、TGF-β1含量、日产奶量均无显著相关性。【结论】在奶牛回乳过程中,添加中药组方"回乳康"能显著促进回乳期奶牛回乳,E是奶牛回乳的负调控激素,TGF-β1是正调控因子,而P4对回乳无明显影响。     

秸秆处理方式及灌溉水源对冬小麦根际土壤酶活性动态变化的影响(英文)

[目的]研究"秸秆还田或不还田"与"地下水或黄河水灌溉"对小麦各生育期土壤酶活性动态变化的影响。[方法]以冬小麦济麦22号为试验材料,采用大田种植试验,研究"秸秆还田或不还田"与"地下水或黄河水灌溉"对冬小麦各生育期根际土壤酶活性的动态变化的影响。[结果]随着生育期的推进,各处理的小麦根际脲酶活性总体呈"上升-下降-上升"的折线变化趋势,转化酶活性和磷酸酶活性总体均成先上升后下降的变化趋势。秸秆还田处理在4个生育期均不同程度的提高了小麦根际脲酶活,同时,除灌浆期外,地下水灌溉比黄河水灌溉更利于小麦根际酶活性的提高。各处理对小麦转化酶活性影响不明显。生育前期,各处理对小麦根际磷酸酶活性的影响较大,在拔节期,秸秆还田处理和地下水灌溉处理能显著提高2种磷酸酶的活性,促进植物和微生物对磷素的吸收和转运;孕穗期地-还处理下土壤酸性磷酸酶的活性显著高于另外3种处理方式。[结论]该研究结果为分析土壤酶活性与作物生长及土壤根际微生物之间存在的动态变化关系奠定了基础。     

Crystal Structure of Kernite, Na2B4O6(OH)2 {middle dot} 3H2

Kernite, Na(2)B(4)O(6)(OH)(2). .3H(2)0, contains parallel infinite chains of the borate polyanion[B(4)O(6)(OH)(2)](n)(2n-). The chains are composed of six-membered rings containing one boron-oxygen triangle and two boron-oxygen tetrahedra. The rings are linked through commonly shared boron-oxygen tetrahedra.     

Synthesis of inorganic fullerene-like molecules

The reaction of [Cp*Fe(eta5-P5)] with Cu(I)Cl in solvent mixtures of CH2Cl2/CH3CN leads to the formation of entirely inorganic fullerene-like molecules of the formula [[Cp*Fe(eta5:eta1:eta1:eta1:eta1:eta1-P5)]12[CuCl]10[Cu2Cl3]5[Cu(CH3CN)2]5] (1) possessing 90 inorganic core atoms. This compound represents a structural motif similar to that of C60: cyclo-P5 rings of [Cp*Fe(eta5-P5)] molecules are surrounded by six-membered P4Cu2 rings that result from the coordination of each of the phosphorus lone pairs to CuCl metal centers, which are further coordinated by P atoms of other cyclo-P5 rings. Thus, five- and six-membered rings alternate in a manner comparable to that observed in the fullerene molecules. The so-formed half shells are joined by [Cu2Cl3]- as well as by [Cu(CH3CN)2]+ units. The spherical body has an inside diameter of 1.25 nanometers and an outside diameter of 2.13 nanometers, which is about three times as large as that of C60.     

Fluorescent guest molecules report ordered inner phase of host capsules in solution

Despite recent strides in the synthesis of elaborate nanometer-scale molecular hosts, the internal structure of these self-assembled cages remains ill characterized. We used fluorescent probe molecules, pyrene butyric acid (PBA), as guests in C-hexylpyrogallol[4]arene capsules to relay information about the chemical environment on the interior of the assemblies. Spectroscopic and single-crystal x-ray diffraction studies show that, in both solution and the solid state, the host can encapsulate two PBA guests and keep them well separated through specific interactions with the capsule walls.     

双拷贝抑制素基因免疫对肉牛卵泡和黄体的影响

 【目的】探讨不同剂量的双拷贝抑制素pcISI基因免疫对肉牛生殖能力的影响。【方法】将58头同期发情肉牛随机分为6组, 每组肉牛分别注射0.75（T1）、1.5（T2）、2.25（T3）、3.0 mg/头（T4）pcISI质粒、3.0 mg/头 pcMV-S空质粒（C1）和3 mL/头 生理盐水（Ｃ2）,初次免疫21d后进行加强免疫,以探讨抑制素pcISI基因疫苗对肉牛卵泡和黄体发育的影响。【结果】4个剂量组的大卵泡数均高于对照组,除了T1外,其它3个剂量组均与对照组差异显著（P＜0.05）;T3和T4的中卵泡数均高于对照组,且差异显著（P＜0.05）;T3和T4的小卵泡数均高于对照组,且差异显著（P＜0.05）。无论左侧还是右侧,各剂量组成熟卵泡直径均高于对照组,除了T1外,其它3组两侧成熟卵泡均与对照组差异显著（P＜0.05）。无论左侧还是右侧,4个剂量组黄体直径均高于对照组,且均与对照组差异显著（P＜0.05）;T3黄体最大,T1最小,且T3与T1差异显著（P＜0.05）。加强免疫后10 d（BM10）抑制素抗体与成熟卵泡大小相关显著（r＝0.629,P＜0.05）,与黄体大小相关极显著（r＝0.651,P＜0.01）。【结论】双拷贝抑制素pcISI基因免疫可促进肉牛卵泡和黄体发育,2.25mg为最佳免疫剂量,抑制素抗体水平与卵泡和黄体发育有一定的相关性。     

早期Ⅱ型糖尿病肾病小鼠模型的建立

[目的]在自发性II型糖尿病小鼠（db／db）基础上建立1种II型糖尿病肾病小鼠模型,为糖尿病肾病新药研发提供高效优质的服务平台。[方法]用II型糖尿病小鼠（db／db）,分别在其4周龄和8周龄进行左侧单肾切除手术．待其康复1周后,再将动物按周龄大小分成2组,另外2组对应周龄的db／db小鼠进行假手术,作为阴性对照组。每2周测定空腹6小时血糖浓度和体重,每4周收集尿液,测定24h微量尿白蛋白总量。[结果]8周龄阴性对照组小鼠与其对应进行单侧肾切除的小鼠空腹6h血糖和体重并无明显差异,但24h微量尿白蛋白总量显著增高,4周龄阴性对照组小鼠与其对应进行单侧肾切除的小鼠相比,其空腹6h血糖和24h微量尿白蛋白总量并无显著增高。[结论]在db／db小鼠8周龄进行单侧肾脏切除可以加速db／db小鼠糖尿病肾病的发生和发展。     

植物乳杆菌对大黄鱼非特异性免疫力的影响

[目的]研究益生菌植物乳杆菌P13对大黄鱼先天免疫力的影响。[方法]用舍植物乳杆菌P13的配方饲料喂养大黄鱼4周后,测定大黄鱼的非特异性免疫指标。[结果]合10^6-10^10cfu／kg Saccharomyces cerevisiae P13的配方饲料可明显提高大黄鱼的补体活性、溶菌酶活性、吞噬活性和头肾白细胞呼吸性。[结论]植物乳杆菌P13能增强大黄鱼先天免疫能力。     

A stable bicyclic compound with two Si=Si double bonds

In contrast to carbon, silicon does not readily form double bonds, and compounds containing silicon-silicon double bonds can usually be stabilized only by protection with bulky substituents. We have isolated a silicon analog of spiropentadiene 1, a carbon double-ring compound that has not been isolated to date. In the crystal structure of tetrakis[tri(t-butyldimethylsilyl)silyl]spiropentasiladiene 2, a substantial deviation from the perpendicular arrangement of the two rings is observed, and the silicon-silicon double bonds are shown to be distorted. Spectroscopic data indicate pronounced interaction between two remote silicon-silicon double bonds in the molecule. Silicon-silicon bonds may be more accessible to synthesis than previously assumed.     

膜下昆虫对滴灌带啃咬的研究

[目的]寻找防止膜下昆虫啃咬滴灌带的方法。[方法]进行对比试验，分别选试验地为草地、试验箱、砼地，膜下昆虫选蝗虫、蟋蟀、地老虎3种，在试验地分别铺设9根滴灌带，膜下放置昆虫，每隔3d抽出部分滴灌带进行漏水检测，同时对剩余滴灌带进行通水，7月试验1次，8月重复上述试验1次。[结果]统计结果表明，昆虫在地膜覆盖条件下为获取水分而啃咬滴灌带，其大规模啃咬通常在滴灌带第2次通水之后发生，其啃咬的部位在滴灌带滴水元件附近的迷宫处，且随着通水次数的增加，滴灌带的非正常漏水点增加。[结论]膜下昆虫啃咬滴灌带是有时间段的，而且有明显的特征部位，建议对滴灌带生产原料进行改进，以防止昆虫啃咬。     

马来西亚与中国相互注册的专利信息对比分析

[目的/意义]马来西亚是重要的"一带一路"沿线国家,国家层面专利信息对比分析具有宏观科技情报意义,能为国家制定相关科技政策提供参考.[方法/过程]本文通过IPC统计与关键词提取解读了马来西亚和中国在对方国家注册专利的技术领域分布,对比分析了注册时间线变化、专利权人类型、引用来源国,再基于IPC共现网络与专利引文类型对两...     

基于PSR模型的都市近郊乡村旅游社区参与模式研究——以重庆市璧山县为例

[目的]完善旅游社区参与模式研究,为相似区域乡村旅游社区参与模式的构建提供借鉴.[方法]以重庆市璧山县为研究对象,分析都市近郊乡村旅游社区参与的特点,并通过该类区域PSR模型的分析,探讨不同游憩带适宜的乡村旅游社区参与模式.[结果]通过充分考虑PSR模型下的区域特点,分别总结出城市游憩圈带、近程游憩带和远程游憩带的游憩地配置模式、社区参与模式及社区发展核心.[结论]乡村旅游社区开发模式的选择应当依托区域要素,构建合理发展机制,避免各种经济、文化冲突.     

长根菇交配系统研究

[目的]研究长根菇交配系统,指导遗传育种工作。[方法]以长根菇子实体为材料,收集并分离单孢,以锁状联合为标记鉴别是否为单核茵丝体。采用三轮交配反应对110株孢子单核体进行三轮两两交配反应。[结果]110株单核体按交配型被分为4组,分别含有21、30、13和46个茵株。[结论]长根菇的交配型受双因子控制,属于四极性交配系统。