Solid-State Synthesis and Thermoelectric Properties of Sb-Doped Mg2Si Materials

Sb-doped magnesium silicide compounds have been prepared through ball milling and solid-state reaction. Materials produced were near-stoichiometric. The structural modifications have been studied with powder x-ray diffraction. Highly dense pellets of Mg₂Si_1?x Sb _x (0 ≤ x ≤ 0.04) were fabricated via hot pressing and studied in terms of Seebeck coefficient, electrical and thermal conductivity, and free carrier concentration as a function of Sb concentration. Their thermoelectric performance in the high temperature range is presented, and the maximum value of the dimensionless figure of merit was found to be 0.46 at 810 K, for the Mg₂Si_0.915Sb_0.015 member.     

Influence of thermal oxidation on the interfacial properties of ultrathin strained silicon layers

In this work we examine the influence of thermal oxidation on the electrical characteristics of ultra-thin strained silicon layers grown on relaxed Si_0.78Ge_0.22 substrates under moderate to high thermal budget conditions in N₂O ambient at 800 °C. The results reveal the presence of a large density of interfacial traps which depends on the oxidation process. As long as the strained silicon layer remains between the growing oxide and the underlying Si_0.78Ge_0.22 layer, the density of interface traps increases with increasing oxidation time. When the oxidation process consumes the s-Si layer the interface state density undergoes a significant reduction of the order of 40%. This experimental evidence signifies that the strained silicon-Si_0.78Ge_0.22 interface is a major source of the measured interfacial defects. This situation can be detected only when the front SiO₂-strained silicon interface and the rear strained silicon-Si_0.78Ge_0.22 interface are in close proximity, i.e. within a distance of 5 nm or less. Finally, the influence of the material quality deterioration—as a result of the thermal treatment—to the interfacial properties of the structure is discussed.     

Fermentation by Amylolytic Lactic Acid Bacteria and Consequences for Starch Digestibility of Plantain, Breadfruit, and Sweet Potato Flours

The potential of tropical starchy plants such as plantain (Musa paradisiaca), breadfruit (Artocarpus communis), and sweet potato (Ipomoea batatas) for the development of new fermented foods was investigated by exploiting the capacity of some lactic acid bacteria to hydrolyze starch. The amylolytic lactic acid bacteria (ALAB) Lactobacillus plantarum A6 and Lactobacillus fermentum Ogi E1 were able to change the consistency of thick sticky gelatinized slurries of these starchy fruits and tubers into semiliquid to liquid products. Consequently, a decrease in apparent viscosity and an increase in Bostwick flow were observed. These changes and the production of maltooligosaccharides confirmed starch hydrolysis. Sucrose in sweet potato was not fermented by strain A6 and poorly fermented by strain Ogi E1, suggesting possible inhibition of sucrose fermentation. In all 3 starchy plants, rapidly digestible starch (RDS) was higher than slowly digestible starch (SDS) and resistant starch (RS) represented between 17% and 30% dry matter (DM). The digestibility of plantain was not affected by fermentation, whereas the RDS content of breadfruit and sweet potato decreased and the RS content increased after fermentation. Practical Application: The characteristics resulting from different combinations of gluten free starchy plants (plantain, breadfruit, sweet potato) and amylolytic lactic acid bacteria (ALAB) offer opportunities to develop new functional fermented beverages, mainly for breadfruit and sweet potato, after further investigation of their formulation, sensory attributes, nutritional, and prebiotic characteristics.     

Food Process Engineering: The Last 25 Years and Challenges Ahead

In the first part of this contribution, an overview is given of some of the main developments in food process engineering in the last 25 years of the 20th century. This overview is, of course, colored by the personal experience of the authors, but a sincere effort was made to maintain a general perspective. Topics that will be briefly discussed are: progress in understanding how to control food microstructure formation during processing, separation processes, conversion processes and stabilization processes, progress in flavor technology and understanding of flavor retention during processing and release. In the 2nd part, in our view, the most exiting future developments are briefly discussed. The major items here are: processing requirements for functional foods, integrated process design approaches, application of novel‘fields’in food processes,‘precision’processing, supply chain approaches to food manufacturing, and more.     

Genetische Differenzierung anhand biochemisch-genetischer Polymorphismen in der Familie derCervidae

Zusammenfassung Cerviden sind genetisch ?hnlich variabel wie auch andere Familien der Mammalier. Basierend auf Untersuchungen anderer Autoren wurde bei der FamilieCervidae eine mittlere Heterozygotie ( ) von ca. 4 % ermittelt. Die Genloci waren zu etwa 1/5 polymorph und wiesen im Mittel etwa 1,3 Allele auf. Für diese Sch?tzma?e genetischer Variabilit?t wurden Untersuchungen folgender Cervidenarten berücksichtigt:Alces alces, Cervus canadensis, C. elaphus, C. nippon, Dama dama, Mazama americana, Odocoileus hemionus, O. virginianus undRangifer tarandus. Innerhalb der Cerviden bestehen beachtliche Unterschiede in der genetischen Variation. Die geringste genetische Variation wurde bisher beiDama dama festgestellt. Aber auchCervus canadensis undAlces alces sind mit Heterozygotiema?en unter 2 % genetisch wenig variabel. Bei diesen Arten waren etwa 10 % der untersuchten Genloci polymorph und im Mittel wurden nicht mehr als 1,14 Allele pro Genlocus festgestellt. Die genetische Variation vonCapreolus capreolus, Rangifer tarandus undCervus elaphus lag geringfügig über dem Gesamtmittel der Cerviden.Odocoileus virginianus war mit =0,097, etwa 40prozentigen Anteil polymorpher Genloci und im Mittel mehr als zwei Allelen pro Genlocus, die genetisch variabelste Hirschart. W?hrend über einzelne Arten, wie z. B. über den Wei?wedelhirsch oder das Ren bereits sehr ausführliche Arbeiten vorliegen, ist der Kenntnisstand genetischer Variation bei anderen Vertretern aus der FamilieCervidae z. T. noch sehr lückenhaft und mu? eher als tentativ angesehen werden. Dies betrifft auch weit verbreitete und jagdlich bedeutsame Arten, wie etwaOdocoileus hemionus oderCapreolus capreolus. Beziehungen zwischen genetischer Variation und quantitativen Merkmalen, wie z. B. Tierk?rpergewicht, Reproduktionsrate, aber auch Geweihentwicklung scheinen bei einigen Cervidenarten zu bestehen. Auch lassen die Befunde beiOdocoileus virginianus undRangifer tarandus auf Assoziationen zwischen Umweltfaktoren und genetischer Variation schlie?en.

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Investigations of genetic differentiation in the Cervidae as determined by protein polymorphisms

Summary On the average the Cervidae show a genetic variability similar to that found in other families within the Mammalia. A mean heterozygosity (II) of about 4% was calculated based on electrophoretic studies of other authors. About 1/5 of the gene loci were polymorphic and about 1.3 alleles per locus were found. The estimates of genetic variability were based on investigations which included the following species:Alces alces, Cervus canadensis, C. elaphus, C. nippon, Dama dama, Mazama americana, Odocoileus hemionus, O. virginianus, andRangifer tarandus. Considerable differences in genetic variation within the Cervidae could be detected. Genetically least variable wasDama dama. But, low genetic variation was also found inCervus canadensis andAlces alces. Heterozygosities within these species were less than 2%, while not more than 1.14 alleles per locus could be observed; and on the average less than 10% of the investigated gene loci were polymorphic. The genetic variation ofCapreolus capreolus, Rangifer tarandus, andCervus elaphus was negligibly higher than the overall estimates for the Cervidae.Odocoileus virginianus was genetically the most variable deer species. Heterozygosity was 0.097, and the proportion of polymorphic loci was about 40% with an average of more than 2 alleles per locus. Whereas for certain species, like white-tailed deer or reindeer, very detailed electrophoretic studies are available, little is known about certain other deer species, and genetic data on these species should be seen as tentative. This also includes widely distributed and extensively hunted species likeOdocoileus hemionus andCapreolus capreolus. Associations between genetic variation and quantitative traits, like carcass weight, reproductive rate or antler development seem to exist in certain deer species. Results inOdocoileus virginianus andRangifer tarandus demonstrate certain relationships between environmental factors and genetic variation.

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Différenciation génétique basée sur des polymorphismes biochimiques-génétiques dans la famille des Cervidés

Résumé Les Cervidés sont génétiquement aussi variables que d'autres familles de mammifères. En se référant à des recherches d'autres auteurs, on a observé, au sein de la famille des Cervidés, un taux moyen d'hétérozygotie ( ) d'environ 4 %. Les loci étaient polymorphes à concurrence de quelque 1/5 et révéaient en moyenne 1,3 allèles. Pour ces estimations de la variabilité génétique, on s'est référé aux espèces de Cervidés suivantes:Alces alces, Cervus canadensis, C. elaphus, C. nippon, Dama dama, Mazama americana, Odocoileus hemionus, O. virginianus et Rangifer tarandus. Parmi les Cervidés, il existe des différences appréciables au niveau de la variation génétique. Jusqu'à présent, la variation génétique la plus faible a été constatée chezDama dama. MaisCervus canadensis etAlces alces montrent aussi, avec des taux d'hetérozygotie inférieurs à 2 %, une variabilité génétique faible. Chez ces espèces, environ 10 % des loci étudiés étaient polymorphes et on ne peut constater en moyenne plus d' 1,14 allèles par locus. La variabilité génétique deCapreolus capreolus, Rangifer tarandus etCervus elaphus se situait légèrement au-dessus de la moyenne générale des Cervides.Odocoileus virginianus, avec un =0,007, un taux de gènes polymorphes de 40 % et avec, en moyenne, plus de deux allèles par locus, se révéla le cervidé génétiquement le plus variable. Tandis que pour certaines espèces, comme par exemple le Chevreuil à queue blanche ou le Renne, il existe déjà une très abondante littérature, l'état des connaissances sur la variation génétique chez d'autres représentants de la famille des Cervidés est encore partiellement très fragmentaire et doit plut?t être considéré comme revêtant un caractère expérimental. Ceci concerne aussi des espècesgibier très répandues commeOdocoileus hemionus etCapreolus capreolus. Des relations entre la variation génétique et des caractères quantitatifs comme, par exemple, le poids corporel, le taux de reproduction mais aussi le développement des bois, semblent exister chez quelques espèces de Cervidés. De même, des observations faites chezOdocoileus virginianus etRangifer tarandus permettent de conclure à des liens entre les facteurs de milieu et une variation génétique.

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Für das Erscheinen der Abhandlung in diesem Heft konnte ein Druckkostenzuschu? des Ministeriums für Landwirtschaft, Weinbau und Forsten des Landes Rheinland-Pfalz eingesetzt werden, für dessen Gew?hrung verbindlich gedankt wird. — Die Schriftleitung.     

Isolation and identification of antimicrobial peptides derived by peptic cleavage of whey protein isolate

The antimicrobial potential of whey protein isolate hydrolyzed by gastrointestinal enzymes was determined by attempting to identify and characterize the antimicrobial peptides responsible. While tryptic and chymotryptic hydrolysates did not show antibacterial activity, whey proteins hydrolyzed for 45–90 min by pepsin exhibited significant activity. Fractionation of 60-min hydrolysate by reversed-phase high performance liquid chromatography yielded 5 fractions that were antibacterial, with minimum inhibitory concentrations comprised between 20 and 35 μg/mL. These fractions contained short peptides not previously identified as antimicrobial. Fragment 14–18 (KVAGT) of β-lactoglobulin is very close to a sequence previously identified as antibacterial and is found in antimicrobial sequences of diverse origin. Five other peptides derived from β-lactoglobulin, and one fragment from α-lactalbumin (f117–121, KVGIN), were also identified as antibacterial. The identified peptides do not match pepsin action exactly, indicating modified proteolysis of unknown origin. Protein by-products of the dairy industry offer potential for large-scale production of antimicrobial peptides.     

聚酯纤维低聚物的存在、分析及最小化

着色聚酯纤维在进一步处理加工中的低聚物问题与纤维本身一样古老,至今仍未解决。到目前为止,由于聚酯纤维重要性的持续增长,已成为最重要的合成纤维,依据目前研究水平,应该弄明低聚物问题真相,采取实用分析技术,找出最有效的应对措施。本文正是这一目的,并且为后整理研究工作者了解、分析并控制低聚物提供一种手段。     

A risk-based sampling plan for monitoring of histamine in fish products

In 2008, the French Institute for Public Health Surveillance reported an increase in the number of histamine food poisoning outbreaks and cases in France. The aim of this study was to propose a new monitoring plan for characterizing consumers' exposure to histamine through fishery products. As fish products of concern are numerous, we proposed that the number of samples allocated for a fish category be chosen based on the risk associated with the category. Point risk estimates of histamine poisoning were assessed with the Risk Ranger tool. Fresh fish with high histidine content was found to contribute most to the number of cases. The (estimated) risks associated with the consumption of canned and deep-frozen fish appear marginal as compared with the risk associated with fresh fish with high histidine concentrations. Accordingly, we recommend excluding canned and deep-frozen fish from the monitoring plan, although these risk estimates can be biased. Within a category, samples were proportional to the relative food consumption of the different fishes. The spatial and seasonal consumption patterns were also taken into account for the design of the new monitoring plan. By testing appropriate numbers of samples from categories of fish products of concern, this plan will permit investigation of trends or comparison of product categories presenting risks of histamine poisoning.     

Bis-(1-chlor-3-phenoxy-prop-2-yl)-sulfane – Nucleophile Substitution und Regiochemie,Diastereomerentrennung und -zuordnung. Synthese diastereomerenreiner Trithiacyclen

Bis-(1-chloro-3-phenoxy-prop-2-yl)-sulfanes – Nucleophilic Displacement and Regiochemistry. Separation and Assignment of Diastereomers. Synthesis of Diastereomerically Pure Trithiacycles The title compounds 1 were substituted by a series of O-, N- and S-nucleophiles (H₂O solvolysis, AgOAc, NaN₃, KSCN, NaSPh, thiourea). A strong tendency to β-elimination of HCl depending on the kind of the attacking nucleophile was found. In most cases no regioisomerization could be detected in the isolated products of the nucleophilic displacement. Best results were obtained with sulfur nucleophiles. The separation of the diastereomeric mixture of the p-kresyl derivative 1b into the individual diastereomers 1bA and 1bB in a preparative scale was achieved. These 3-thia-1,5-dichlorides and several products of substitution could be assigned to the meso- or (±)-form by examination of the stereochemistry and symmetry of the corresponding sulfoxides. The 1,5-dimercapto derivatives 8 are convenient as structural units for the synthesis of diastereomerically pure cis- or trans-disubstituted trithiacycles e.g. 15bA , 15bB . The (±)-form of the 4,6-disubstituted 2,5,8-trithia[9]-(2,6)-pyridinophane 16bA was characterized by X-ray crystal structure determination.