盐和有机酸对肉制品嫩度的影响

在肉的所有食用品质中,嫩度被消费者认为是最重要的因素.为了满足消费者的需要,国内外学者分别从宰前因素(品种、年龄、性别、营养状况、肌肉部位等)和宰后因素(宰后生物化学变化、加工方法等)对嫩度进行了研究,并提出了许多嫩化方法.……     

杂种野猪宰后肌肉品质特性的研究

猪的品种是影响猪肉食用品质的最主要因素,而猪肉的化学组成成分和宰后生理生化变化则是肌肉品质形成的基础。针对杂种野猪和本地白猪两种不同的品种猪在相同条件下饲养和屠宰,研究了宰后肌肉的色泽红度a值、pH值、嫩度(剪切力)和蒸煮损失的变化情况。试验表明,杂种野猪肉红度较深且保持时间长,pH值高,嫩度差,蒸煮损失少。     

重金属锌污染砂的交流电阻率特性试验

为研究交流电阻率法检测重金属锌污染的可行性,通过对不同的锌污染砂试样进行电阻率测试,分析了电流频率、含水量、孔隙比、锌污染含量等对砂电阻率的影响,建立了影响锌污染砂交流电阻率的经验公式。结果表明,电阻率随电流频率的增加先急速降低,当电流频率增加到50 kHz时,电阻率逐渐趋于稳定;以锌含量50 mg/kg为界,锌含量越低,电阻率对电流频率的变化越敏感;电阻率随含水量的增加而减小,含水量越低,电阻率变化越快;电阻率随孔隙比的增加而增大,增幅较缓;电阻率随锌含量的增大而急速减小,当锌含量高于250 mg/kg后,电阻率逐渐趋于稳定;砂电阻率与锌污染含量间呈现高度相关的幂函数关系,得出了包含饱和度、孔隙率、锌污染含量的砂交流电阻率关系公式。     

基于转录组筛选肉牛骨骼肌差异基因

旨在基于转录组筛选肉牛骨骼肌差异基因,探究差异基因对骨骼肌转录调控的影响,鉴定其与肌肉生长发育的关系,为研究骨骼肌生长发育的分子机制提供理论依据。采取12月龄的布莱凯特黑牛和鲁西黄牛背最长肌,利用Illumina 2500进行转录组测序,通过综合生物信息学分析(差异基因筛选、GO分类、KEGG富集分析和蛋白互作网络等)筛选骨骼肌差异的调控基因。布莱凯特黑牛和鲁西黄牛2个文库分别存在13 242,13 350个基因,共计13 758个基因。5 500个基因表达量相同,约占总参考基因的39. 98%,8 258个基因表达量有所不同,占比60. 02%。获得554个差异显著的基因作为差异表达基因,其中296个基因表达上调,258个基因表达下调。GO功能注释结果显示,生物学过程、细胞组分和分子功能分别包括22 641,7 720和4 414个基因,其中29个基因与肌细胞的发育和分化有关; KEGG富集到Wnt、CMC、TGF-β、DCM、ROAC、VSMC 6条肌肉生长发育相关通路,筛选骨骼肌候选基因MYL2、MYL3和MYLPF。MYL2、MYL3和MYLPF是Wnt、DMC和TGF-β信号通路中的成员,参与了肌细胞和肌肉组织的形成的过程,推测MYL2、MYL3和MYLPF在骨骼肌生长发育过程中发挥重要作用。     

不同频率下超声波水处理对苹果内传热传质影响规律的试验研究

为探究超声波处理对果蔬加工过程中热质传递的影响规律,以苹果为研究对象,结合不同频率（40、68、80 kHz）超声波处理技术,分别进行超声波辅助低温水浴试验和超声波水预冷处理辅助苹果片真空冷冻干燥试验。结果表明：超声波辅助低温水浴可有效强化苹果与冷水间的热量交换,频率为80 kHz时,苹果果肉中部和近果核处的冷却系数与对照组相比分别增加了35.3%和28.6%;超声波水预冷处理后,真空冷冻干燥过程有效水分扩散系数比对照组分别增加了51.6%（超声波频率40 kHz）、55.9%（超声波频率68 kHz）、58.7%（超声波频率80 kHz）。     

药用植物五味子生物活性物戈米辛J对超负荷运动肌肉损伤的影响及分子机制

本研究旨在探究药用植物五味子中的生物活性物戈米辛J对超负荷运动引起的肌肉损伤的影响及其机制。通过对超负荷运动诱导的骨骼肌损伤模型进行实验,研究发现戈米辛J能够显著减轻肌肉损伤程度。机制研究表明,戈米辛J具有抗氧化和抗炎作用,能够提高骨骼肌中抗氧化酶的水平,减少氧自由基的产生,降低氧化应激损伤。此外,戈米辛J还通过抑制炎症信号通路的活化,减少炎性因子的释放,抑制骨骼肌的炎症反应。同时,戈米辛J还能够改善线粒体功能,促进线粒体呼吸链复合物的活性,从而加速肌肉损伤的修复过程。综上所述,戈米辛J作为五味子中的活性成分,通过抗氧化、抗炎和改善线粒体功能等多种途径,对超负荷运动引起的肌肉损伤具有保护作用。本研究结果为进一步探索五味子的临床应用提供了重要的理论依据。     

免疫球蛋白样和纤维连接蛋白Ⅲ型域含蛋白IGFN1参与骨骼肌应激损伤调控的研究进展

IGFN1基因可在骨骼肌中特异性表达,并呈现出免疫球蛋白Ⅰ和纤维连接蛋白Ⅲ组合的肌小节蛋白的结构域特征。其作用主要是参与蛋白翻译、肌细胞分化、骨骼肌收缩和细胞骨架稳定等。本研究主要对IGFN1基因的结构特点、在动物体内的基因表达调控、参与的信号转导途径,以及动物氧化应激反应与IGFN1表达之间的关系等方面的相关研究进展进行综述,以期为骨骼肌纤维类型转换相关机制的研究提供资料,也为氧化应激条件下修复肌肉损伤及改善猪肉品质的深入研究提供新思路。     

灌溉制度对机采棉生长、产量及品质的影响

1膜2管6行是新疆机采棉的主要种植模式。为确定该模式适宜的灌溉制度,采用田间试验研究了灌溉频率(F5、F8)与灌水定额(I80、I60和I40)对棉花生长、产量、品质及水分利用效率的影响。结果表明,高频高定额(F5I80)与高频中定额(F5I60)灌溉可有效降低棉花株高,增加叶面积指数,提高蕾铃生物量在地上部中的比例。灌溉频率相同时,灌水量过高与过低均不利于棉花增产;灌水定额相同时,高频(F5)较低频(F8)灌溉增产0.59%~1.56%。灌溉制度对棉花纤维品质无显著影响。灌水定额显著影响棉花耗水量及水分利用效率,而灌溉频率对二者影响不显著。研究认为高频(F5)和中灌溉定额(I60)是南疆地区机采棉种植模式适宜的灌溉制度,即在全生育期内灌水12次,灌溉定额300 mm左右。     

饲喂杂交狼尾草青贮料对猪生产性能和肉质的影响

为了研究饲喂酶制剂青贮的杂交狼尾草对公猪和母猪生长性能及肉品质的影响,笔者开展了4种杂交狼尾草青贮处理,组Ⅰ为杂交狼尾草添加麦麸,组Ⅱ为杂交狼尾草添加麦麸和纤维素酶,组Ⅲ为杂交狼尾草添加麦麸和纤维素菌液,组Ⅳ为杂交狼尾草添加麦麸和乳酸菌。将4种方式处理的杂交狼尾草添加至基础日粮中,对照组只饲喂基础日粮,75天后称重计算猪的日增重,将猪屠宰后分别测定宰后1 h和宰后24 h的pH和肉色,以及宰后24 h的肌肉大理石纹和系水力。结果表明：Ⅰ-Ⅳ处理组和CK组的公猪日增重分别比母猪高出7.8%、6.7%、12.2%、1.1%和10.7%;Ⅰ-Ⅳ处理组公猪和母猪平均日增重分别比CK组提高3.31%和5.58%;处理组公猪和母猪的pH₁、pH₂₄和肌肉干物质含量与对照组差异不显著(P>0.05),但饲喂杂交狼尾草后公猪的肌肉干物质含量会适当降低,母猪的肌肉干物质含量、肉色₁、肉色₂₄和大理石纹值均略有提高。同时肉猪特别是公猪的系水力也会提高,猪肉品质得到改善。这说明饲喂酶制剂青贮的杂交狼尾草既能提高公猪和母猪的日增重,还能改善猪肉品质,这为开发酶制剂青贮的杂交狼尾草猪饲料奠定基础。     

植物源性芥子酸对运动性骨骼肌损伤大鼠骨骼肌氧化应激和线粒体功能的影响

本研究旨在探究植物源性芥子酸(SA)对运动性骨骼肌损伤(EIMD)大鼠骨骼肌的氧化应激与线粒体功能的影响。采用一次性离心运动建立EIMD大鼠模型,灌胃芥子酸1周后进行检测。结果表明,芥子酸剂量依赖性地改善了EIMD大鼠的血清与骨骼肌指标,显著降低了LDH、CK和TNF-α水平,提高了骨骼肌中SOD、CAT活性并降低了MDA水平。同时,通过提高骨骼肌Nrf2 (细胞核)、HO-1和NQO--1蛋白表达以及降低Keap1蛋白表达,展现了明显的抗氧化作用。此外,芥子酸还能增强骨骼肌CⅠ～CⅣ活性,并促进NRF1和TFAM蛋白表达,从而改善线粒体功能和促进线粒体再生。总体来看,本研究证实芥子酸在调节EIMD大鼠骨骼肌的抗氧化能力和线粒体功能方面具有重要作用。     

The use of electrical impedance spectroscopy to assess the physiological condition of kiwifruit

The electrical impedance of kiwifruit [Actinidia deliciosa (A. Chev) C.F. Liang et A.R. Ferguson, cv. Hayward] was studied during fruit ripening. Measurements were made on whole fruit, and tissues excised from the outer pericarp, inner pericarp and core. Alternating current at frequencies between 50 Hz and 1 MHz was passed through fruit and tissue samples, and complex impedance spectra were separated into the resistances of the apoplast, cytoplasm and vacuole, and capacitances of the plasma membrane and tonoplast. The differences in R_50 Hz and R_1 MHz between tissues (representative of apoplast resistance and total tissue resistance, respectively) were explained in terms of the anatomy and composition of the respective tissues. Some variations were seen from one year to the other. During ripening, there was little change in the impedance characteristics of the fruit, despite a 10-fold decrease in firmness. This was unexpected since previous studies with nectarine, persimmon and tomato fruit have shown a considerable reduction in impedance during ripening. The failure to observe any impedance change was checked using a number of different methods for measuring impedance, by two different laboratories, and confirmed by measuring electrolyte leakage from tissue discs. All the results suggested that the mobility of electrolytes within the cell wall did not change during kiwifruit ripening. We speculate that physicochemical interactions that take place within the cell wall may have a major impact on the impedance of kiwifruit tissue.     

Numerical analysis on the performance of spiral antennas

The surfaces of the Planar Spiral Antennas and Conical Spiral Antennas are analyzed with planar triangle. The surface currents of the antennas are solved by using the Method of Moment (MoM) based on the RWG basis function. The input impedance, directivity, gain, radiated power and radiation field of the antenna can be found. The results indicate that, in very wide frequency band, the value of the input impedance equals to the theoretical value of Self-Compensated antennas (in agreement with Babinet-booker' principle), which is,188.5 ohm , the half of the wave impedance of free space, while the directivity, gain and radiated power are stable within the frequency band. When the antenna is driven by the signal of derivative Gaussian pulse, the radiating electric field waveform is obtained by the Fourier transform. When the spiral antenna is used as the pulse radiation antenna, the waveform of the radiation electric field shows the characteristics of the Gaussian quadratic differential.     

肉品的嫩化机制、方法及其影响因素

肉品嫩度是肉的主要食用品质之一,它是消费者评判肉质优劣的最常用指标。由肌肉转变为可食性肉,到最后的嫩化成熟是一个复杂过程。宰后肉类的后期成熟和嫩化处理,是改善肉品嫩度的关键环节。该文主要阐述了影响肉嫩度的因素（宰前和宰后因素）、嫩化方法以及嫩化机制（如：电刺激、盐类、酶法、有机酸、超声波、高压和吊挂拉伸等）,为肉制品加工企业品质改良提供理论支持。     

Electrical Impedance Technology Applied to Examining Brain Edema

Biological electrical impedance is a physical quantity to reflect electricity character of biological tissue, apparatus, cell or whole organism, which is a kind of new method developed recently to analyze component of body. This technology is unhurt examining method which obtains certain biomedicine information about human body according to electrical character and change of biological tissue or apparatus, has unhurt, cheap, safe, innocuity, operator simple and abundant information etc., is prone to be accepted by doctors and patients. Now unhurt brain electrical impedance double channel examining system and brain electrical impedance topographic mapping system have entered clinical experiment moment, and contactless magnetic induction tomography(CMIT) is taken notice of widely as a more effective examining method.     

Post-process of Finite Element Method in Electrical Impedance Tomography

In the research of electrical impedance tomography (EIT), each calculation may produce a large amount of data(such as conductance , resistance etc.). The rule of these data is not clear and is hard to understand. How to express the calculation result by means of image in order that such parameters as conductance and resistance can be grasped from the image is significant in analyzing and understanding the calculation result and is helpful to the doctor. This paper has discussed the realization of the post-process of finite element method in electrical impedance tomography and we have developed the software of the post-process of finite element method using Visual C++ .NET and OpenGL. Some problems in drawing the contour line and color contour band have been solved properly.     

Modeling and simulation based on open electrical impedance tomography

In order to improve the error in image reconstruction caused by changeable positions of the electrodes in closed electrical impedance tomography, we propose an open electrical impedance tomography (OEIT) model using fixed electrode array. The problem was approximately assumed to be a virtual field by defining certain local sensitive area instead of solving the boundary problem in the whole electromagnetic field strictly. Modeling and simulation of OEIT have been conducted to define reasonable boundary parameters and electrode array structure. The finite element method is used for forward computation while Newton one step error reconstructor is used for image reconstruction. The target position, area and conductivity change can be reflected by the relative change of the boundary voltage and the reconstructed image is clear. Better resolution and positioning accuracy can be obtained in the shallower surface of the body by OEIT, so it is valuable in clinical applications.     

苹果砧木实生后代枝条电阻抗参数与抗寒性的相关性

以苹果砧木实生后代单株为试材,研究低温胁迫下苹果砧木实生后代枝条电阻抗（EIS）参数（胞外电阻率re、胞内电阻率ri、电阻率r1和弛豫时间τ）的变化,并分析电阻抗图谱法和常规的电导法测定的苹果砧木抗寒性的相关性。结果表明,随着温度降低,苹果砧木枝条的胞外电阻率re、胞内电阻率ri、电阻率r1和弛豫时间τ均减小。以苹果砧木枝条的EIS参数电阻率r1、胞外电阻率re、胞内电阻率ri求得的抗寒性与EL法测定的抗寒性呈显著性正相关（r=0.838～0.906）。r1测定的苹果砧木枝条的抗寒性与EL法测定的抗寒性相差10℃,不适合用于测定苹果砧木枝条的抗寒性。表明经低温胁迫后的苹果砧木枝条用re和ri可以测定苹果砧木枝条的抗寒性。     

Simulation of an automobile ignition system electro magnetic interference

When an ignition system operates, conducted interference caused by transient voltage of the primary circuit will impact on the accumulator and the disturbance will travel throughout the vehicle via wiring. The ignition system can disrupt the Electronic Control Unit and the normal operation of other electrical devices. Spark plug gap noise simultaneously produces very strong radiation interference in a vehicle. We analyzed the changes of the ignition coil voltage and current when an ignition switch was turned on and off. A discharged circuit model of spark plug also was set up. The electric field distribution in an automobile was calculated. For these calculations, the high voltage wire was considered to be a unipole antenna. This simulation indicates that using either damped wire or adding spark plug resistance can suppress spark noise effectively.     

Instantaneous Frequency Estimation of the Surface Myoelectric Signal Wigner-Ville Distribution Based Technique

The analysis of the surface myoelectric signal is a valuable and the signal is recorded while a muscle is performing a sustained contraction tool for assessing the progression of localized fatigue. Mean and median frequencies of an electromyogram power spectrum are often used as indicators of muscular fatigue during static contraction. To evaluate muscle fatigue during cyclic dynamic contraction, according to the features of surface myoelectric signal during dynamic contraction, an instantaneous frequency detection technique based on cross Wigner-Ville distribution is proposed. The estimation error of the algorithm by means of a simulated stochastic process with statistical properties similar to the those of surface myoelectric signal. The theoretical and experiment validates that the instantaneous frequency suites well to tracking spectral changes due to muscle fatigue with very low SNR.