Effect of Different Packaging Methods on Quality and Shelf Life of Fresh Reindeer Meat

The impact of different packaging methods [vacuum, modified atmosphere packaging (MAP) (60% CO₂ and 40% N₂) and MAP + CO₂ emitter] on the quality of fresh reindeer meat (M. semimembranosus) stored at 4°C for 21 days was investigated. Colour and odour of the meat, drip loss, pH, microbial content, antioxidant capacity and cooking loss were measured. The MAP + CO₂ emitter resulted in prolonged microbial shelf life compared with vacuum and MAP without CO₂ emitter as lower level of total viable counts was detected after 13 and 17 days. Samples stored with CO₂ emitter also had lower drip loss. Samples stored in vacuum had significant lower L*‐value, higher a*‐value and lower intensity of freshness (odour and colour) compared with those stored in MAP and MAP with CO₂ emitter. However, MAP with a gas‐to‐product volume ratio of 1 : 1 seems to be too low in quality preserving. Increased partial pressure by adding a CO₂ emitter improved bacterial inhibition compared with vacuum and traditional MAP. Copyright © 2014 John Wiley & Sons, Ltd.     

In vivo toxicity and biodistribution of intraperitoneal and intravenous poly-l-lysine and poly-l-lysine/poly-l-glutamate in rats

The combination of two differently charged polypeptides, poly-l-lysine (PL) and poly-L-glutamate (PG), has shown excellent postsurgical antiadhesive properties. However, the high molecular, positively charged PL is toxic in high doses, proposed as lysis of red blood cells. This study aims to elucidate the in vivo toxicity and biodistribution of PL and complex bound PLPG comparing intravenous and intraperitoneal administration. Fifty-six Sprague–Dawley rats were used in a model with repeated blood samples within 30 min examining blood gases and blood smears. Similarly, FITC labelled PL were used to track bio distribution and clearance of PL, given as single dose and complex bound to PG after intravenous and intraperitoneal administration. Tissue for histology and immunohistochemistry was collected. Blood gases and blood smears as well as histology points to a toxic effect of high dose PL given intravenously but not after intraperitoneal administration. The toxic effect is exerted through endothelial disruption and subsequent bleeding in the lungs, provoking sanguineous lung edema. FITC-labelled PL experiments reveal a rapid clearance with differences between routes and complex binding. This study advocates a new theory of the toxic effects in vivo of high molecular PL. PLPG complex is safe to use as antiadhesive prevention based on this toxicity study given that PL is always intraperitoneally administered in combination with PG and that the dose is adequate.     

Strategies for revealing deformation and wear mechanisms of polymer composites by combining scanning electron microscopy,energy dispersive x-ray spectroscopy and cross-section techniques—Exemplified by glass fiber reinforced poly-phenylene-sulphide

Polymers and polymer composites are frequently used in tribological applications. However, their use is often limited by excessive wear or plastic deformation, therefore research and development aiming to improve the materials is ongoing. Tribological evaluations of polymer composites often study the friction coefficient and wear rate for different types, sizes and amounts of fillers. But rarely are any mechanisms presented. Although polymer materials differ from metals, the techniques typically used for metal components, for example, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), can be adapted to polymer materials, to achieve more informative SEM micrographs and EDS analyses. The aim of this article is to present useful analysis strategies, from sample preparation and selection of viewing angles, to selection of instrument settings and detector types. The strategies are exemplified by analysis of poly-phenylene-sulphide filled with glass fiber, evaluated against steel in a reciprocating ball-on-flat test set-up. This article takes its starting point with the worn surfaces, and subsequently analyze them using SEM and EDS. A selection of cross section preparation techniques, analysis parameters and microscopy settings are presented and discussed. By combining these techniques and settings, the observation of a strongly modified surface layer, as well as sub-surface plastic deformation and imbedded wear particles, is facilitated.     

Sensory and chemical evaluation of Thymus zygis L. essential oil and compressed CO2 extracts

The effects of the extraction procedure on the sensory and chemical evaluation of Thymus zygis L. aromatic extracts obtained by hydro distillation and compressed CO₂ extraction were studied. Compressed CO₂ extractions were performed at a temperature of 313 K and 10 and 15 MPa of pressure for 60 min. Aromatic extracts were analysed by GC and GC-MS. Sensorial analysis of the aromatic extracts incorporated into a sunflower oil was carried out by a panel of 20 trained members. The main compounds of Thymus zygis essential oil obtained by Clevenger distillation are: p-cymene (13.6%), thymol (23.8%), geraniol (18.2%), and geranyl acetate (16.3%). The compositions of supercritical extracts are quite different. The detection threshold of Thymus zygis essential oil was 0.001 mg/kg sunflower oil. The preferred level of essential oil incorporation was 0.02 mg/kg sunflower oil (P<0.05). Sensorial attributes were correlated with chemical compositions and it can be concluded that extracts with higher levels of phenols and geranyl acetate were preferred.     

A Large 16*16 IF Analog Switch Matrix for Personal Communications Satellites

A 16 input and 16 output channels single chip intermediate frequency range (160 MHz) analog switch matrix for personal communication satellites has been designed and processed by using a commercial 1.2 µm BiCMOS technology. The circuit has low power consumption (,2W) and low insertion loss with maximum output power of 0 dBm.     

Decrease in cardiovascular disease mortality in the Czech Republic from 1984 to 1993 and its possible causes

BACKGROUND: The objective of the investigation was to evaluate the ten-year development of the cardiovascular mortality rate in two population groups in the age bracket from 25 to 64 years, i.e. in subjects living in six districts which participated in the international WHO project MONICA and in the population of the whole Czech Republic. METHODS AND RESULTS: Data on the mortality rate in 1984-1993 for the age group from 25-64 years were provided by the Institute of Health Information and Statistics, information on the prevalence of risk factors was obtained in three cross-sectional studies implemented in six districts as part of the MONICA project in 1985, 1988 and 1992. In the mortality rate per 100,000 population in the six districts the following changes were revealed (in parentheses the values for 1984 and 1993 are given): men - a statistically significant declining trend in the from all caused mortality (849.3-742.5; p < 0.001) and cardiovascular mortality (367.2-280.4; p < 0.001) and cerebrovascular mortality (69.7-44.8; p < 0.001). In the mortality from ischaemic heart disease (215.7-170.6; ns) a declining trend was not recorded. In women aged 25-64 years in the six districts there was a statistically significant decline of the mortality from all caused (359.5-322.1; p < 0.001), the cardiovascular mortality (115.6-100.6; p < 0.001) and cerebrovascular mortality (31.1-23.6; p < 0.001). The mortality from ischaemic heart disease did not change (49.2-48.8; ns). In the population of the Czech Republic in men the following were detected: a drop of the from all caused mortality (907.1-784.8; P < 0.001), the cardiovascular mortality (383.5-308.4; p < 0.001) and cerebrovascular mortality (76.5-55.3; p < 0.001). Also in women of the Czech Republic a decline of the mortality from all caused was recorded (390.1-328.5; p < 0.001), the cardiovascular mortality (135.3-103.8; p < 0.001), ischaemic heart disease (58.0-48.6; p < 0.001) and cerebrovascular mortality (43.5-27.4; p < 0.001). In 1990 an increased cardiovascular mortality was recorded in men different from the trend during 1984-1993, statistically significant in the Czech Republic (p < 0.05) and in the six districts (p < 0.05). The reasons of this trend are not clear. The role of health services in the mortality drop is not clear, although available data indicate their improvement. Favourable changes were found in risk factors: during the period from 1985-1992 the prevalence of hypercholesterolaemia declined significantly in men and women, the prevalence of hypertension in women and the prevalence of smoking in men declined in the six districts. From nationwide data ensues that after 1989 significant changes occurred in the diet of the Czech population. The meat consumption declined by 1993 by 13%, the milk and dairy product consumption by 26.8% the butter consumption by 43.6% the consumption of vegetable fats increased by 16%, of vegetables by 8%, tropical fruit by 43.2%. These changes probably had an impact on the cholesterol level and BMI of the Czech population. CONCLUSIONS: In the declining cardiovascular mortality trend during 1984-1993 the following may have participated: improved medical care, dietary changes, improvement of the risk profile and other, in particular socioeconomic factors. With regard to the close temporal association of the investigated changes it may be assumed that this development is at least partly associated with changes of the political and economic position in the Czech Republic after 1989.     

A mathematical model for the solute drag effect on recrystallization

The model for the solute drag effect in phase transformations has been applied to recrystallization, i.e., moving grain boundaries. In this model, the total driving force is dissipated by the interfacial energy, the finite interfacial mobility, the solute drag in boundaries, and diffusion in the matrix ahead of the interface, of which all are taken into account consistently. The effects of the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries were investigated. The results show that the Gibbs energy of segregation mainly affects the critical composition at which the drastic change in the boundary velocity appears, and the diffusivity of impurity atoms in boundaries mainly affects the velocity reduced by the solute drag effect. In other words, the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries can be evaluated from experimental data by means of the present model. This model was applied to the Al−Mg system, and the Gibbs energy of segregation and the diffusivity of Mg in boundaries were evaluated from experimental data. The evaluated Gibbs energy of segregation agrees with the estimate based on elastic energy considerations. The diffusivity estimated from this model is smaller than that measured along the grain boundary. ZI-KUI LIU, formerly with the Department of Materials Science and Engineering, Royal Institute of Technology     

Esterification of ethenyl benzene and its derivatives with acetic acid in the presence of perchloric acid as a catalyst

The esterification process of ethenyl benzene and its derivative compounds (p-methyl, p-methoxy, p-chloro, m-methyl, m-nitro and m-chloro, respectively) was carried out with acetic acid and using perchloric acid as a catalyst. From the effects of the variables studied it could be concluded that: the temperature and the catalyst concentration influence positively over the olefin conversion, whereas the initial olefin concentration exert no effect over the same; and that the presence of perchloric salts exerts a different influence, depending on the temperature and on the catalyst concentration. It has been proven that the substituted radicals in the m- or p- positions exert an important influence over the conversion of the studied olefins, presenting growing reactivity in the following order: m-nitro ethenyl benzene, m-chloro ethenyl benzene, p-chloro ethenyl benzene, m-methyl ethenyl benzene, ethenyl benzene, p-methyl ethenyl benzene and p-methoxy ethenyl benzene. Finally, a kinetic and thermodynamic study has been done and the corresponding parameters have been calculated, with an adequate fitting.