Apparatus for slab polyacrylamide gel electrophoresis

An apparatus for eight-channel gel electrophoresis on polyacrylamide slabs is described. It can be easily and cheaply constructed. The use of the buffer for cooling enables high voltage gradients to be applied giving good separation and resolution in under 2 h. A destaining apparatus, which does not use electrophoresis and is suitable for slab or “disc” gels, has been developed.     

Apparatus for slab polyacrylamide gel electrophoresis

An apparatus for eight-channel gel electrophoresis on polyacrylamide slabs is described. It can be easily and cheaply constructed. The use of the buffer for cooling enables high voltage gradients to be applied giving good separation and resolution in under 2 h. A destaining apparatus, which does not use electrophoresis and is suitable for slab or “disc” gels, has been developed.     

A Partitioned Slab Apparatus for One-Dimensional Polyacrylamide Gel Electrophoresis in Multiphasic Buffer Systems under a Wide Range of Conditions

Abstract

An apparatus for one-dimensional polyacrylamide gel electrophoresis in multiphasic buffer systems of multiple samples on a gel slab has been constructed. This apparatus is made of Pyrex, providing satisfactory wall adherence of polyacrylamide at any pH, 0 and 25°C. The apparatus provides permanent sample partitions and can, therefore, be used with mechanically labile, stacking gels. Temperature control for polymerization and electrophoresis is provided. Procedures and applications are described for use of the apparatus with uniform gel concentration or with pore gradient gels. A gradientmaker for the preparation of polyacrylamide pore gradient gels is described.     

Identification of extrinsic proteins in boneless cooked ham by SDS-PAGE: detection level in model systems

Protein extraction and separation in polyacrylamide slab gel electrophoresis with Laemmli system (SDS-PAGE) were used to establish the detection level of protein raw materials in mixtures with porcine meat in boneless cooked ham. Model systems of boneless cooked ham with soy protein isolates, caseinate, skim powdered milk, bovine plasma, porcine plasma and whey proteins were studied. The quantification level of this method was 0.5% for soy protein isolates, caseinate and bovine plasma and 1.0% for porcine plasma, milk powder and whey proteins in boneless cooked ham. The electrophoretic method proved to be useful to identify some proteinic raw materials in porcine meat products and verify compliance with Argentine legislation. It may be used as a control methodology.     

Influence of pre-electrophoresis on protein separations in polyacrylamide gels

Polyacrylamide gel electrophoresis (PAGE) is a widely used technique in protein separations. In this study, the effects of pre-electrophoresis (i.e., exposing polyacrylamide gels to an electrical field prior to loading samples) on the separation of a mixture of 10 standard proteins was investigated. Three different gel concentrations (based on amounts of acrylamide and bis-acrylamide, always at a 37.5:1 ratio) relative to the volume of the gel solution were tested: 6%, 9%, and 12%. For each concentration, multiple slab gels were subjected to pre-electrophoresis prior to separation of proteins, while multiple other (i.e., companion) slab gels were used but without applying the pre-electrophoresis technique. Separation results were investigated, showing that the application of the pre-electrophoresis technique had a significant effect on separations particularly for 6% and 9% gels.     

Isoelectric Focusing of Proteins in Gel Media

Abstract

Separation of proteins according to their isoelectric point can be performed in a pH gradient formed by stationary electrolysis of carrier ampholytes. The pH gradient is stabilized by the use of polyacrylamide, agarose, and Sephadex gels. Separated proteins can be detected by fixation with trichloroacetic acid followed by nonspecific staining, by specific staining, or through immunodiffusion techniques. Isoelectric focusing of proteins in gel media can be carried out in gel columns or on thin-layer plates by using conventional electrophoresis apparatus. Electrofocusing can be followed by electrophoresis in gel media for more complete separation of components.

Multiple samples of microgram quantities can be analyzed simultaneously by simple and rapid procedures. These methods have both analytical and preparative applications in protein fractionation work.     

刚玉-莫来石推板的研制与应用

研究了颗粒组成、结合剂种类及含量对刚玉 -莫来石质推板热震稳定性的影响。结果表明 :当颗粒料中莫来石与刚玉的质量比为 3∶1时 ,试样的抗折强度保持率最高 ,与颗粒料全部采用莫来石颗粒或刚玉颗粒相比 ,110 0℃ 水冷 3次后的抗折强度保持率分别提高了 2 5 %和 35 %。另外 ,用硅铝凝胶替代粘土作结合剂 ,也可提高刚玉 -莫来石质推板的热震后抗折强度保持率。研制出的刚玉 -莫来石推板的高温强度高 ,110 0℃ 水冷循环的热震次数超过 4 5次。经国内某厂家试用 ,其寿命可达 12 0次。     

软磁铁氧体烧结氮窑用推板的现状与发展

介绍了我国软磁铁氧体烧结氮窑用推板的生产和使用情况 ,指出由于国产的推板使用寿命短、性能的一致性和可靠性差 ,国内使用的推板主要依赖进口。为实现软磁铁氧体烧结氮窑用推板国产化 ,研究的重点是 :(1)优化原料组成和推板配方 ;(2 )改进生产工艺和生产装备 ;(3)进行模拟使用研究 ,提高检测水平     

Nonuniform Pressure Device for Bonding Thin Slabs to Substrates

A method employing compliant solid cylinders and spheres as pressure applicators has been developed for use in bonding large-area slabs (e.g. 8' × 1/4' × 0.010' thick) to solid substrates or to other slabs backed temporarily by solid substrates. The compliant body body produces a pressure profile causing the viscous bonding agent (e.g. epoxy resin) to flow toward the edges of the slab. The rate of compression of the cylinder is immaterial to the process; sufficient force may be applied instantly to flatten the cylinder against the entire top surface of the slab without impeding the viscous flow. The pressure gradient depends on the Young's modulus and the radius of the compliant solid body, so proper cylinders and spheres can be procured to cause very viscous bonding agents to flow into very thin layers. Several successful bonds have been made with overall thicknesses of 150 Angstroms except around dirt particles.     

Nonuniform Pressure Device for Bonding Thin Slabs to Substrates

A method employing compliant solid cylinders and spheres as pressure applicators has been developed for use in bonding large-area slabs (e.g. 8″ × 1/4″ × 0.010″ thick) to solid substrates or to other slabs backed temporarily by solid substrates. The compliant body body produces a pressure profile causing the viscous bonding agent (e.g. epoxy resin) to flow toward the edges of the slab. The rate of compression of the cylinder is immaterial to the process; sufficient force may be applied instantly to flatten the cylinder against the entire top surface of the slab without impeding the viscous flow. The pressure gradient depends on the Young's modulus and the radius of the compliant solid body, so proper cylinders and spheres can be procured to cause very viscous bonding agents to flow into very thin layers. Several successful bonds have been made with overall thicknesses of 150 Angstroms except around dirt particles.     

REFRACTORIES UNDER LOAD CONDITIONS1

Life factors.—The life of fire clay slabs, rings and saggers is influenced by a number of factors, both mechanical and chemical. The chief factors controlling the life of the slabs are (1) proper selections of clays and grog, (2) medium absorption or porosity, (3) strength in the unburned state, (4) proper and thorough blending and preparation of the mix, (5) proper pressing so as to insure freedom from flaws, (6) proper drying, (7) proper setting in the kilns and especially (8) initial burn. These factors are briefly discussed. Setting.—The manner of setting grinding wheels, using large slabs is described. This manner of setting causes transverse bending stress to be set up in the slab and shear stresses to develop. This shearing force, in connection with the large size and the high temperature (cones 11 to 12), make severe conditions for the slab to withstand. Shape and size.—The rate of heating and the size and shape of the slabs are additional factors. Round slabs, up to about 20° in diameter have a decidedly longer life when made in two half sections as compared with the solid shape. Larger slabs have longest life when split up into four sections, while if solid they will fail in one burn. Warping of the slabs, as well as cracking, causes failure. In general, if the width of area of the load is held constant, and length of span of the slab is increased, deformation and cracking is slightly increased. If the span is held constant, and the width or load area is increased warpage is greatly increased, especially as the number of burns under load increases. Cracking also increases in direct proportion to increase in width. These features are more pronounced the longer the span. Ultimate failure at high temperatures.—When not due to structural defects, failure is brought about by a gradual decrease in mechanical strength from burn to burn, so that fire-clay slabs under transverse load at such temperatures have decided limitations     

Separation and Recovery of Proteins by Elution-Convection

Abstract

The design, construction, and operation of an apparatus for preparative electrophoresis is described. This apparatus employs high-resolution gel electrophoresis to separate protein components with subsequent electro-convection to effect their elution and concentration.     

Phase variation and mechanical properties of waste calcium carbonate to substitute quartz in composite slab production

Owing to the fast-emerging nature and rapid advancements in the construction industry, huge volumes of marble dust (MD) are generated as reject during slab cutting in marble processing, causing significant environmental hazards. Nowadays, quartz composite slabs have increasingly been preferred in building works due to their excellent hygienic property and mechanical strength. Composite slab is produced using micronized quartz as filler, the grinding of which is an energy-intensive process. Substitution of micronized quartz with MD at different percentages was investigated in natural form and after roasting. Natural MD offered appreciable physical properties closer to those of a quartz composite slab. Physical properties slightly retrograded by quartz supplementation in the raw form. Roasting the filler led to the formation of rounded Ca–silicate. Wollastonite was the first phase formed after sintering at the lowest MD percentage and shortest roasting times. Larnite became dominating phase first by increasing MD percentage and roasting time, and then calcio-olivine formed. Physical characterization test results demonstrated that hardnesses of new phase and particle shape were the key parameters that improved slabs’ mechanical properties of. Hard rounded larnite particles improved mechanical behavior of slabs having the synergic effect of quartz, whereas wollastonite did not show a significant effect.     

Numerical observations on symmetric and asymmetric profiles in catalyst slabs

A numerical procedure is described for generating either symmetric or asymmetric steady-state mass and temperature profiles in a catalyst slab. Observations on the dynamic behavior of these catalyst slabs and the stability of the steady-state profiles are quoted. The validity of the frequently used assumption of symmetry or isothermality of a catalyst particle is also discussed.     

Effect of Internal Curing on Moisture Gradient Distribution and Deformation of a Concrete Pavement Slab Containing Pre-Wetted Lightweight Fine Aggregates

Internal curing technology has been proven effective in improving many properties of concrete. The application of this technology to the transportation infrastructure holds promise with increasing resistance to cracking and enhanced durability. On the other hand, an investigation of moisture distribution in concrete slabs is of significance for predicting slab deformation and the associated stress and failure. This study is performed to investigate the characteristics of the pre-wetted sintered fly ash lightweight fine aggregate (LWFA) used as an internal curing agent and the influence of internal curing on concretes exposed to sealed curing, external drying, and surface wetting conditions. The internal curing effects on the moisture distributions in concrete pavement slabs at w/c = 0.3 and 0.4 were evaluated through experimental measurements, and the effects on slab deformations were quantified using an equivalent temperature difference. The findings of this study will benefit the further application of internal curing technology to the transportation infrastructure's construction.     

DRYING OF SOLIDS: THE INFINITE SLAB CONDITION

ABSTRACT

Fourier's second law was solved using convective boundary conditions without considering the shrinkage of the solid. The solutions for a finite and an infinite slab were compared to determine the dimensions for a slab to be considered as infinite. The solutions obtained for Bi = 0.1 and Bi = 100 correspond to heat and mass transfer-controlled processes, respectively, during drying. The results show that the finite slab cannot be considered as infinite, even for R²/R¹ > 20. The relative error obtained when the finite slab was assumed to be infinite was not significant for small Fourier numbers, but it increased as the Fourier number increased; errors were also higher for higher Biot numbers. When the numerical solution of a drying model was obtained for finite and infinite slabs, significant differences in drying kinetics and temperature evolution were observed.     

A Proteomic Analysis of Human Follicular Fluid: Comparison between Younger and Older Women with Normal FSH Levels

The follicular fluid (FF) is produced during folliculogenesis and contains a variety of proteins that play important roles in follicle development and oocyte maturation. Age-related infertility is usually considered as a problem that can be solved by assisted reproduction technology. Therefore, the identification of novel biomarkers that are linked to reproductive aging is the subject of this study. FF was obtained from healthy younger (20–32 years old) and older (38–42 years old) women undergoing intracytoplasmic sperm injection (ICSI) due to male factor infertility. The FF was analyzed by two-dimensional gel electrophoresis (2-DE). The power of two-dimensional gel electrophoresis and the identification of proteins were exploited using matrix-assisted laser desorption-ionization time-of-flight/time-of-flight (MALDI-TOF-TOF) mass spectrometry. Twenty three protein spots showed reproducible and significant changes in the aged compared to the young group. Of these, 19 protein spots could be identified using MALDI-TOF-TOF-MS. As a result of MASCOT search, five unique downregulated proteins were identified in the older group. These were identified as serotransferrin, hemopexin precursor, complement C3, C4 and kininogen. A number of protein markers were found that may help develop diagnostic methods of infertility.     

Experimental investigation into the influence of ignition location on flame spread and heat release rates of polyurethane foam slabs

This study presents the results from a set of 11 large‐scale open fire tests performed on flexible polyurethane foam slabs/mattresses. The purpose of the study was to investigate the influence of the ignition location on the fire behaviour of the foam slabs and to generate data on a highly characterised material that could be used for modelling work in the future. A method for obtaining spatially resolved flame spread data for this type of material was presented using a gridded array of 5 × 10 thermocouples placed on the underside the foam slab and from this, flame spread was examined using three different approaches. The heat release rate (HRR) results showed clear shapes forming that were dependent on the ignition location, with two distinct behaviours being observed between the various different ignition locations, this was also observed in the calculated flame spread rate (FSR) data. Results within an individual test, showed the calculated range of FSRs over the geometry of the slab varied between approximately 1 and 8 mm/s depending on the ignition location. The average FSR values between tests varied between 3 and 7 mm/s and the maximum and minimum values were calculated to be approximately 11 and 2 mm/s respectively.     

GFRP筋混凝土板正截面抗弯承载力研究

为了研究GFRP筋混凝土板的正截面抗弯承载力,基于平截面假定、内力平衡条件以及变形协调条件,对GFRP筋混凝土板在适筋及适量超筋两种配筋设计情形下的正截面抗弯承载力计算公式进行了推导,通过8组具有不同配筋率与混凝土强度等级的GFRP筋混凝土板抗弯承载力试验,对推导的计算公式进行了验证,同时研究了构件抗弯承载力与配筋率、混凝土强度等级之间的变化关系。结果表明:试验得到的极限承载力与公式计算的理论承载力数据吻合较好,可以较准确地反映GFRP筋混凝土板抗弯承载力的计算过程;适量超筋设计构件破坏形式表现为以受压区混凝土被压碎为标志的塑性破坏,这种设计方式更有利于提高GFRP筋混凝土板的安全性能;同时为了保证混凝土板达到极限承载力时受拉区GFRP筋不被拉断,建议设计配筋率取1.4倍的平衡配筋率;随着GFRP筋混凝土板配筋率的增加,构件承载力系数逐渐增大,安全储备也逐渐提高;GFRP筋混凝土板的抗弯承载力随着配筋率与混凝土强度的增加而逐渐增大。     

Thin copper foil heater for measuring the thermal conductivity of polymers

A new and rather simple apparatus is described for measuring the thermal conductivity of insulating materials. The technique employs a double‐sided, copper‐coated plastic sheet, known as a printed circuit board, to generate a nearly uniform wall heat flux. Heating is achieved by passing an electrical current through the copper coating. Identical sample slabs are placed against opposite sides of the heater, and the combination is placed in a bath having constant and uniform temperature. When thermal equilibrium is reached, the temperature drops across the central portions of the sample slabs are measured with thermocouples. The one‐dimensional form of Fourier heat transfer equation is used to compute thermal conductivity from the observed quantities. In preliminary tests with polymer materials, equilibrium is reached within half an hour. It is estimated that the apparatus is capable of giving measurements accurate to within 5%, and experimental results are consistent with this estimate. Thermal conductivity values are reported for pure polyethylene (PE) and PE mixed with aluminum powder and carbon black. Also reported is the thermal conductivity of pure polycarbonate (PC) and PC mixed with carbon black. The results obtained with the present apparatus are consistent with previous findings. The characteristics of the apparatus make it especially suitable for academic laboratory instruction and for low temperature thermal conductivity measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2823–2827, 2003