Effects of Heat and Iron Fractions on Lipid Oxidation in Meat.

Size exclusion (SE) and hydrophobic interaction (HIC) high performance liquid chromatography (HPLC) methods were developed for determining hemoglobin, myoglobin, and total pigments in beef and chicken. Hemoglobin and myoglobin in beef, but not in chicken, were separated by HIC with minimum detectable levels of 0.187 and 0.085 $\mu$g/$\mu$l, respectively. Determination of total pigment by SE-HPLC (minimum detection of 0.001 $\mu$g/$\mu$l) was more sensitive than with spectrophotometric assay. The effects of heat at 55\sp\circC, 70\sp\circC, 85\sp\circC, and 100\sp\circC on the distribution of iron in six fractions (water-soluble, water-insoluble, diffusate, hematin, total heme, and ferritin) in beef and chicken muscles were determined. Iron content decreased (p $\u3c$ 0.05) in water-soluble fractions and increased (p $\u3c$ 0.05) in water-insoluble fractions as temperature increased to 100\sp\circC. The content of heme iron was decreased more from 55\sp\circC to 85\sp\circC than from 27\sp\circC to 55\sp\circC or 85\sp\circC to 100\sp\circC. The increase in the amount of diffusate iron appeared to be less than the decreased amount of heme iron at each heating temperature level. As temperature increased, hematin iron content was increased (p $\u3c$ 0.05) and ferritin iron content was decreased (p $\u3c$ 0.05). More ferritin iron was decreased (p $\u3c$ 0.05) at temperature of 70\sp\circC than at 55\sp\circC. The catalytic abilities of heat at 55\sp\circC, 70\sp\circC, 85\sp\circC, and 100\sp\circC and nine forms of iron (water-extractable iron, diffusate iron, non-diffusate iron, hematin, Hb, Mb, ferritin, FeCl\sb2 and FeCl\sb3) on lipid oxidation in water-extracted meat residues (WR) and solvent-extracted fat emulsion (FE) of beef and chicken muscles were studied. Heat and different forms of iron promoted lipid oxidation (p $\u3c$ 0.05) in WR and FE for both species. The catalytic abilities of the same forms of iron were different in WR and FE. All forms of iron catalyzed lipid oxidation in WR, however, ferritin, FeCl\sb2, or FeCl\sb3 did not increase lipid oxidation in FE. Heme iron was the major catalyst of lipid oxidation in FE, while both heme iron and iron in the low molecular weight fractions (diffusate iron) had high catalytic activity for lipid oxidation in WR

Optimal parameter for the SOR-like iteration method for solving the system of absolute value equations

The SOR-like iteration method for solving the absolute value equations~(AVE) of finding a vector $x$ such that $Ax - |x| - b = 0$ with $\nu = \|A^{-1}\|_2 < 1$ is investigated. The convergence conditions of the SOR-like iteration method proposed by Ke and Ma ([{\em Appl. Math. Comput.}, 311:195--202, 2017]) are revisited and a new proof is given, which exhibits some insights in determining the convergent region and the optimal iteration parameter. Along this line, the optimal parameter which minimizes $\|T_\nu(\omega)\|_2$ with $$T_\nu(\omega) = \left(\begin{array}{cc} |1-\omega| & \omega^2\nu \\ |1-\omega| & |1-\omega| +\omega^2\nu \end{array}\right)$$ and the approximate optimal parameter which minimizes $\eta_{\nu}(\omega) =\max\{|1-\omega|,\nu\omega^2\}$ are explored. The optimal and approximate optimal parameters are iteration-independent and the bigger value of $\nu$ is, the smaller convergent region of the iteration parameter $\omega$ is. Numerical results are presented to demonstrate that the SOR-like iteration method with the optimal parameter is superior to that with the approximate optimal parameter proposed by Guo, Wu and Li ([{\em Appl. Math. Lett.}, 97:107--113, 2019]). In some situation, the SOR-like itration method with the optimal parameter performs better, in terms of CPU time, than the generalized Newton method (Mangasarian, [{\em Optim. Lett.}, 3:101--108, 2009]) for solving the AVE.Comment: 23 pages, 7 figures, 7 table

Automated Refactoring of Nested-IF Formulae in Spreadsheets

Spreadsheets are the most popular end-user programming software, where formulae act like programs and also have smells. One well recognized common smell of spreadsheet formulae is nest-IF expressions, which have low readability and high cognitive cost for users, and are error-prone during reuse or maintenance. However, end users usually lack essential programming language knowledge and skills to tackle or even realize the problem. The previous research work has made very initial attempts in this aspect, while no effective and automated approach is currently available. This paper firstly proposes an AST-based automated approach to systematically refactoring nest-IF formulae. The general idea is two-fold. First, we detect and remove logic redundancy on the AST. Second, we identify higher-level semantics that have been fragmented and scattered, and reassemble the syntax using concise built-in functions. A comprehensive evaluation has been conducted against a real-world spreadsheet corpus, which is collected in a leading IT company for research purpose. The results with over 68,000 spreadsheets with 27 million nest-IF formulae reveal that our approach is able to relieve the smell of over 99\% of nest-IF formulae. Over 50% of the refactorings have reduced nesting levels of the nest-IFs by more than a half. In addition, a survey involving 49 participants indicates that for most cases the participants prefer the refactored formulae, and agree on that such automated refactoring approach is necessary and helpful

Construction and Transformation of a Thermotoga-E. coli Shuttle Vector

Background: Thermotoga spp. are attractive candidates for producing biohydrogen, green chemicals, and thermostable enzymes. They may also serve as model systems for understanding life sustainability under hyperthermophilic conditions. A lack of genetic tools has hampered the investigation and application of these organisms. This study aims to develop a genetic transfer system for Thermotoga spp. Results: Methods for preparing and handling Thermotoga solid cultures under aerobic conditions were optimized. A plating efficiency of similar to 50% was achieved when the bacterial cells were embedded in 0.3% Gelrite. A Thermotoga-E. coli shuttle vector pDH10 was constructed using pRQ7, a cryptic mini-plasmid found in T. sp. RQ7. Plasmid pDH10 was introduced to T. maritima and T. sp. RQ7 by electroporation and liposome-mediated transformation. Transformants were isolated, and the transformed kanamycin resistance gene (kan) was detected from the plasmid DNA extracts of the recombinant strains by PCR and was confirmed by restriction digestions. The transformed DNA was stably maintained in both Thermotoga and E. coli even without the selective pressure. Conclusions: Thermotoga are transformable by multiple means. Recombinant Thermotoga strains have been isolated for the first time. A heterologous kan gene is functionally expressed and stably maintained in Thermotoga

Monobutyl phthalate induces the expression change of G-Protein-Coupled Receptor 30 in rat testicular Sertoli cells

The aim of the study was to explore whether G-Protein-Coupled Receptor 30 (GPR30) was expressed in rat testicular Sertoli cells and to assess the impact of monobutyl phthalate (MBP) on the expression of GPR30 in Sertoli cells. By using RT-PCR, Western-Blot and immunofluorescent microscopy, the expression of GPR30 in rat Sertoli cells was found at both gene and protein level. Cultures of Sertoli cells were exposed to MBP (10– –1000 mM) or a vehicle. The results indicated that the expression of GPR30 increased at gene and protein levels in Sertoli cells following administration of MBP even at a relatively low concentration. We suggest that changes of GPR30 expression may play an important role in the effects of the xenoestrogen MBP on Sertoli cell function. (Folia Histochemica et Cytobiologica 2013, Vol. 51, No. 1, 18–24

Natural transformation of Thermotoga sp. strain RQ7

Background Thermotoga species are organisms of enormous interest from a biotechnological as well as evolutionary point of view. Genetic modifications of Thermotoga spp. are often desired in order to fully release their multifarious potentials. Effective transformation of recombinant DNA into these bacteria constitutes a critical step of such efforts. This study aims to establish natural competency in Thermotoga spp. and to provide a convenient method to transform these organisms. Results Foreign DNA was found to be relatively stable in the supernatant of a Thermotoga culture for up to 6 hours. Adding donor DNA to T. sp. strain RQ7 at its early exponential growth phase (OD600 0.18 ~ 0.20) resulted in direct acquisition of the DNA by the cells. Both T. neapolitana chromosomal DNA and Thermotoga-E. coli shuttle vectors effectively transformed T. sp. strain RQ7, rendering the cells resistance to kanamycin. The kan gene carried by the shuttle vector pDH10 was detected by PCR from the plasmid extract of the transformants, and the amplicons were verified by restriction digestions. A procedure for natural transformation of Thermotoga spp. was established and optimized. With the optimized method, T. sp. strain RQ7 sustained a transformation frequency in the order of 10−7 with both genomic and plasmid DNA

The Existence of Periodic Orbits and Invariant Tori for Some 3-Dimensional Quadratic Systems

We use the normal form theory, averaging method, and integral manifold theorem to study the existence of limit cycles in Lotka-Volterra systems and the existence of invariant tori in quadratic systems in ℝ3