毛细管电泳法测定猪体组织中甜菜碱含量

建立了毛细管电泳法快速测定猪体组织中甜菜碱含量的方法。甜菜碱首先转化为苯甲酰甲基酯后直接上样测定。pH为 3 .0的磷酸缓冲溶液使甜菜碱酯化物和甜菜碱结构类似物酯化物之间以及酯化物和酯化剂之间都能很好地分离 ,这也省去了反应混合液的前处理。该法标准曲线的线性范围为 4～ 6 0 0mg L ,相关系数r为 0 .9999,最低检测限为 1mg L ,相对标准偏差为 2 .2 %～ 4.7% ,标准加入回收率为 95 9%～ 98.4%     

猪胰脏中铁钙镁铜铅锌镉锰钴镍的测定

采用硝酸－过氧化氢在自动回流消化仪中消化猪胰脏,火焰原子吸收光度法测定铁、钙、镁、铜、锌、铅、镉、锰、钴、镍的含量。,方法简便,快速,结果令人满意,并对猪胰脏食用价值进行了评价。     

Thermo-elastic behavior of a polymeric layer bonded between rigid interfaces

A highly expandable polymeric material have been combined with a stiff skeleton material to form a powerful design of thermal micro-actuators. The bond interfaces with the skeleton laterally restrain deformation of the polymer and consequently direct its volumetric expansion in the transverse direction. A complete lateral constraint at the infinite bond width could maximize the apparent thermal strain of the bonded polymer. However, it is not sure how much strain enhancement can be achieved using a finite bond width. To answer this, we resort to an approximate thermo-elastic model and solve it using the mean-pressure method. This model leads to closed-form solutions to the thermally induced strains and stresses in a bonded polymer layer between rigid interfaces. The closed-form solution shows that the apparent strain of a bonded layer depends on the aspect ratio of the bond width to the layer thickness, besides Poisson’s ratio. Furthermore, it further shows that a bond width five times the thickness of the SU-8 epoxy layer is sufficient to attain 95% of the maximum apparent strain, which is obtained at the infinite width.     

高效液相色谱法分析牛和猪肌肉组织中残留的安乃近药物的三种代谢物

建立了牛和猪肌肉组织中残留的安乃近药物的3种代谢物 4-甲酰氨基安替比林（FAA）、4-氨基安替比林（AA）和 4-甲基氨基安替比林（MAA）的高效液相色谱测定法。肌肉组织样品均质后采用硫酸钠-亚硫酸钠溶液提取,过滤后经C18固相萃取柱净化,采用Inertsil ODS-3色谱柱分离,甲醇和水梯度洗脱,于265 nm波长下检测,外标法定量FAA,内标法定量AA和MAA（以 4-异丙基氨基安替比林作为内标物）。FAA的检出限为12.5 μg/L,AA的检出限为15.0 μg/L,MAA的检出限为20.0 μg/L;3种代谢物的测定低限均为50 μg/L;在添加水平为50～400 μg/kg范围内,FAA的回收率为81.3%~92.5%,AA的回收率为82.0%~96.0%,MAA的回收率为80.4%~90.6%,相对标准偏差均在7%以内。     

逐步回归在牲猪生产决策中的应用

湖南省是我国的牲猪生产区，邵阳市又是湖南的牲猪生产区之一．近几年来，邵阳市牲猪生产一直徘徊不前，为寻找影响牲猪生产的原因，本文选取粮食产量、牲猪外调量、家禽产量等多个因素，采用逐步回归的方法，求得它们影响牲猪出栏量的多元线性回归模型，并据此对１９９１年牲猪生产状况进行了预测，提出了恢复牲猪正常发展的努力方向和应采取的基本对策．     

A Reevaluation of the Critical Membrane Potential of the Effective Refractory Period in Guinea Pig Ventricular Fibres

The traditional critical membrane potential (CMP), -55—-60mV, which corresponds to effective refractory period (ERP), was anew investigated in guinea pig ventricular muscle fibres. The electrical and contractile responses to the stimulus during repolarization of action potential (AP), particularly from+10 to -60 mV, were observed. One third of 35 tested cells displayed testing action potential (TAP) and local response at≥-54 mV when they were stimulated by testing pulses in 37℃ normal Tyrode's solution. Potential level of TAP which occurred earliest was at -30 mV and that of local response which appeared earliest was at 0 mV during repolarization among 95 systematic tests. Most of the TAPs belonged to the slow response potential type. The ratio of TAP evoked at ≥-54 mV initial membrane potential (IMP) was as high as 86% when the experiment was carried out in 37℃ 1.5 mmol KC1/L Tyrode's solution. In view of distribution of IMPs of TAPs, the CMP of ERP in guinea pig ventricular muscle fibres was more     

郁金对胃平滑肌条运动的影响

目的：观察利胆药物——郁金对兔离体胃平滑肌的影响．方法：取兔胃肌条，安置在各恒温灌流肌槽中并用BL-310生物技能实验系统记录胃各部平滑肌条的收缩活动．结果：郁金显著升高兔胃底和胃体纵行肌条张力，减小胃体收缩波平均振幅，并有剂量依赖关系．结论：郁金对胃肌条收缩活动具有明显的兴奋作用，这种兴奋作用部分经由胆碱能M受体介导．     

A confocal study of mechanism of 5-hydroxytryptamino induced intracellular calcium dynamics in cultured rat stomach fundus smooth muscle cells with a new Ca~(2+) indicator STDIn-AM

A new fluorescent Ca2+ indicator STDIn-AM for detecting [Ca2+]i transients in cultured smooth muscle cells is presented. By making a comparison, the difference between STDIn and fluo-3 is discussed in detail. Using the new Ca2+ indicator, the mechanism of 5-hydroxytryptamino (5-HT) induced intracellular calcium dynamics in stomach fundus smooth muscle cells (SFSMC) of rats is investigated. It is shown that in contrast with fluo-3, STDIn is uniformly distributed in the cytosolic compartment but excluded from the nucleus, when it is transfected into cells. This feature makes it a real cytosol Ca2+ indicator and can reflect changes of cytosol [Ca2+] more accurately than that of fluo-3. In addition, STDIn responds to the [Ca2+]i transients more sensitive and faster than fluo-3. The results also show that, the L-type Ca2+channel inhibitor Mn9202 and the PLC inhibitor Compound 48/80 can significantly inhibit the [Ca2+]i elevation induced by 5-HT, while the PKC inhibitor D-Sphingosine can enhance the effect of     

Microcalorimetric Investigations of K+- and Mg2+-Induced Polymerization of Actin at Temperatures from 293.15 K to 310.15 K

Microcalorimetric measurements of the polymerization of actin in the presence of 100 mM KCl and 2 mM MgCl₂were carried out with a Calvet MS-80 microcalorimeter at temperatures from 293.15 to 310.15 K. It was observed that the polymerization of actin was endothermic and the enthalpy change for actin polymerization was temperature-dependent. The enthalpy change ΔH^owas fitted to ΔH^o(kJ mol^-1)=434.0-1.16 (T/K) and the change in heat capacity ΔC_p ^ocalculated from ΔH^owas -1.16 kJ (mol K)^-1in the above range of temperatures. The direct calorimetry results showed that the enthalpy and entropy change for actin polymerization could not be obtained from measurements of the critical concentration and the only way to assess the enthalpy change for the polymerization of actin and similar reactions lies in the use of calorimetry. This revised version was published online in July 2006 with corrections to the Cover Date.     

Validation of a method for the analysis of quinolones residues in bovine muscle by liquid chromatography with electrospray ionisation tandem mass spectrometry detection

A liquid chromatography-tandem mass spectrometry method for the determination and confirmation of nine quinolones was optimised and validated according to Commission Decision 2002/657/EC. Analytes were extracted from veal muscle with water and extracts purified with 96-well plates Oasis HLB cartridges. Separation was carried out in a silica-based C₁₈ column (50 mm × 2.1 mm) with mobile phases consisting of water/acetonitrile mixtures containing acetic acid. Linear calibration curves in the ranges 4-400 and 50-800 ng g⁻¹, with correlation coefficients at least 0.995, were obtained for all the analytes. At concentration levels above 10 ng g⁻¹, quantification errors were lower than 10% and repeatability and within-laboratory reproducibility standard deviations below 6% and 10%, respectively. Decision limits and detection capabilities are reported.