The effect of cryoprotectants during freezing or freeze drying upon properties of washed mechanically recovered broiler meat

Mechanically recovered meat (MRM) from broilers was washed three times with water and subjected to either slow or rapid freezing or freeze-drying with, or without, the presence of cryoprotectants. Both freezing and freeze-drying reduced the functionality of the MRM when no cryoprotectants were used. Sorbitol/sucrose showed some protection of gel forming ability of frozen samples whilst sorbitol/sucrose with tripolyphosphate gave stronger gels after freezing or freeze-drying than fresh samples. Most of the loss of functionality during freezing or freeze-drying was caused by loss of solubility of myosin and to a lesser extent actin. This was supported by DSC studies. The combined presence of sorbitol/sucrose/tripolyphosphate restored most functional properties of the frozen or freeze-dried material to that of the fresh material.     

The construction and cloning of synthetic genes coding for artificial proteins and expression studies to obtain fusion proteins

Synthetic genes coding for artificial proteins with predeflnedand nutritionally valuable amino acid compositions have beenconstructed and cloned In bacterial plasmid vector pKK233-2.The genes were constructed from three easily interchangeable‘cassettes’ encoding either essential, non-essentialor branched-chain amino acid residues. A potential hairpin loopstructure in the mRNA around the region of the ribosome bindingsite was probably the reason for blockage of translation fromthis vector. Two selected genes, AHB (containing one copy ofeach cassette) and A (consisting of six copies concatemerizedA₆cassette) were cloned into pUR300, a (ß-Gal fusionvector and expressed as fusion proteins (ß-Gal-AHBand (ß-Gal-A₆.     

RBF-based neurodynamic nearest neighbor classification in real pattern space

Superposition of radial basis functions centered at given prototype patterns constitutes one of the most suitable energy forms for gradient systems that perform nearest neighbor classification with real-valued static prototypes. It is shown in this paper that a continuous-time dynamical neural network model, employing a radial basis function and a sigmoid multi-layer perceptron sub-networks, is capable of maximizing such an energy form locally, thus performing almost perfectly nearest neighbor classification, when initiated by a distorted pattern. The proposed design scheme allows for explicit representation of prototype patterns as network parameters, as well as augmenting additional or forgetting existing memory patterns. The dynamical classification scheme implemented by the network eliminates all comparisons, which are the vital steps of the conventional nearest neighbor classification process. The performance of the proposed network model is demonstrated on binary and gray-scale image reconstruction applications.     

Phonon-Induced Superconductivity and the Staggered Magnetic Field on a Square Lattice

We have considered phonon-induced superconductivity on a square lattice. The antiferromagnetic correlations that are present in high-temperature superconductors (HTSC) have been simulated by the staggered magnetic field. The Eliashberg equations have been generalized to account for the momentum dependent order parameter, and the superconducting transition temperature T _c has been evaluated within the strong-coupling theory. The two-dimensional band structure has explicitly been taken into account. It occurs that the results obtained for T _c when considering d-wave symmetry of the superconducting state much better reflect the experimentally observed behavior than those derived for s-wave symmetry. The isotope shift exponent has also been evaluated. One can observe that the introduction of the staggered magnetic field leads to the decrease of this quantity. Therefore, the presence of the staggered magnetic field may contribute to experimentally observed values of smaller than the BCS value of 1/2     

Phase transitions in monolayer formed by hyperbranched polyester with alkyl-terminated branches at the air/water interface

Investigations of Langmuir and Langmuir–Blodgett molecular films of hyperbranched polyester with alkyl-terminated branches over a wide temperature range revealed an unusual phase transitions. The measured surface pressure–surface area isotherms clearly show that the hyperbranched polyester formed stable and well-defined monolayers at the air/water interface. At temperatures below 313 K ice floe-like structures of a condensed phase were formed already from very low surface pressures. On the increase of the surface pressure the floes of the condensed phase merged forming a uniform monolayer. Above 313 K a surface liquid phase was formed at the interface. It was shown that the phase transition from the surface liquid phase to the condensed phase occurred on temperature decrease. At lower temperatures the compression process was not reversible. The increase of temperature up to about 323 K made the compression process reversible. The monolayers were transferred from the air/water interface onto silicon and mica substrates using the Langmuir–Blodgett technique at different temperatures. The structure of the polyester monolayer formed at the substrates' surfaces was investigated.     

Effect of Dimer Structure and Inhomogeneous Broadening of Energy Levels on the Action of Flavomononucleotide in Rigid Polyvinyl Alcohol Films

The results of time-resolved fluorescence measurements of flavin mononucleotide (FMN) in rigid polyvinyl alcohol films (PVA) demonstrate that fluorescence intensity decays are strongly accelerated in the presence of fluorescent dimers and nonradiative energy transfer processes. The fluorescence decay originating both from H and J dimer states of FMN was experimentally observed for the first time. The mean fluorescence lifetimes for FMN dimers were obtained: τfl = 2.66 ns (at λ_exc = 445 nm) and τfl = 2.02 (at λ_exc = 487 nm) at λ_obs = 600 nm and T = 253 K from H and J state of dimers, respectively. We show that inhomogeneous orientational broadening of energy levels (IOBEL) affects the shape of the fluorescence decay and leads to the dependence of the average monomer fluorescence lifetime on excitation wavelength. IOBEL affected the nonradiative energy transfer and indicated that different flavin positioning in the protein pocket could (1) change the spectroscopic properties of flavins due to the existence of “blue” and “red” fluorescence centers, and (2) diminish the effectiveness of energy transfer between FMN molecules.     

Compatibility of Distinct Label-Free Proteomic Workflows in Absolute Quantification of Proteins Linked to the Oocyte Quality in Human Follicular Fluid

We present two separate label-free quantitative workflows based on different high-resolution mass spectrometers and LC setups, which are termed after the utilized instrument: Quad-Orbitrap (nano-LC) and Triple Quad-TOF (micro-LC) and their directed adaptation toward the analysis of human follicular fluid proteome. We identified about 1000 proteins in each distinct workflow using various sample preparation methods. With assistance of the Total Protein Approach, we were able to obtain absolute protein concentrations for each workflow. In a pilot study of twenty samples linked to diverse oocyte quality status from four donors, 455 and 215 proteins were quantified by the Quad-Orbitrap and Triple Quad-TOF workflows, respectively. The concentration values obtained from both workflows correlated to a significant degree. We found reasonable agreement of both workflows in protein fold changes between tested groups, resulting in unified lists of 20 and 22 proteins linked to oocyte maturity and blastocyst development, respectively. The Quad-Orbitrap workflow was best suited for an in-depth analysis without the need of extensive fractionation, especially of low abundant proteome, whereas the Triple Quad-TOF workflow allowed a more robust approach with a greater potential to increase in effectiveness with the growing number of analyzed samples after the initial effort of building a comprehensive spectral library.     

Technology of braze welding absorber tubes to copper foil in solar collectors by the GTA method

The classification of aluminium alloys on the basis of main alloy elements and usability for heat treatment is presented. The essential problems occurring in welding of aluminium and its alloys are mentioned. The most advanced methods of joining these materials are described. Results of investigations into the possibility of joining of thin walled elements of aluminium alloys by low heat input arc welding methods, plasma arc welding and hybrid laser+MIG welding are also presented.     

Bivalent peptides as models for multimeric targets of PDZ domains

PDZ domains are among the most common modules in eukaryotic, including human, genomes. They are found exclusively in large, multidomain cytosolic proteins--often with other domains that belong to a variety of families--and are involved in a plethora of physiological and pathophysiological events. PDZ domains mediate protein-protein interactions by binding to solvent-exposed and extended C-terminal short fragments of membrane-associated proteins, such as receptors and ion channels. Most of what is known about the mechanisms of target binding by PDZ domains is inferred from studies that involve isolated recombinant PDZ domains and short synthetic peptides that represent the targets. These binary systems constitute an obvious oversimplification and disregard factors such as noncanonical modes of binding and enhanced affinity due to multimeric interactions mediated by clusters and oligomers of PDZ-domain-containing proteins. We have tested whether the interaction between a dimeric form of PDZ domain that mimics a functional dimeric guanine nucleotide exchange factor, PDZ-RhoGEF (PDZ-containing RhoA-specific guanine nucleotide exchange factor) or LARG (leukemia-associated RhoA specific guanine nucleotide exchange factor), and a bivalent peptide that mimics the dimer of the plexin B receptor, could enhance the interaction between the two moieties. Peptide dimerization was achieved by cross-linking the N-terminal ends of peptides attached to Wang resin with poly(ethylene glycol) spacers (30-45 Angstroms in length). The interaction of dimeric PDZ domains with dimeric peptides resulted in an up to 20-fold increase in affinity compared to the simple binary system. This is consistent with the notion that multimerization of both receptors and PDZ-containing proteins might constitute an important regulatory mechanism.     

耐腐蚀性镍基箔带钎料钎焊不锈钢接头性能

采用新型耐腐蚀性镍基箔带钎料BNi685对316L不锈钢进行真空钎焊,研究了钎焊间隙对钎缝组织及力学性能的影响,对比了新型BNi685钎料钎焊接头与商用BNi2钎料,BNi685膏状钎焊接头的耐腐蚀性. 结果表明,随着钎焊间隙的增加,钎焊接头的抗拉强度逐渐降低,钎缝中心的显微硬度增加. 钎焊间隙为50 μm时,接头平均抗拉强度为244 MPa,钎缝组织主要由Ni_2.9Cr_0.7Fe_0.36,CrNiP,Cr₃P,Ni₅Cr₃Si相组成. 随着钎焊间隙增加,钎缝中心的CrNiP,Cr₃,Ni₅Cr₃Si相增多,Ni_2.9Cr_0.7Fe_0.36相减少. BNi685钎料钎焊接头的耐腐蚀性优于BNi2和BNi685膏状钎料钎焊接头,在EGR冷却器制造领域具有较大的应用潜力.