Home About us Contact
|
Home About us Contact | ||
|
|
||
Rich Material (rich + material)
Selected AbstractsOrobanche benkertii sp. nova (Orobanchaceae Vent.) und weitere Orobanche -Sippen aus dem Nordwest-KaukasusFEDDES REPERTORIUM, Issue 1-2 2004St. Rätzel Im Verlaufe von zwei Exkursionen des Erstautors in den Nordwest-Kaukasus (Republik Adygeja) in den Jahren 2001 und 2002 konnte reichhaltiges Material der Gattung Orobanche L. gesammelt werden. Im Ergebnis der Durchsicht der Belege wurden weitere Erkenntnisse insbesondere zu den weniger bekannten Endemiten Orobanche gamosepala, O. grossheimii und O.inulae gewonnen sowie sechs neue Taxa (Orobanche benkertii sp. nova, O. laxissima sp. nova, O. alba subsp. xanthostigma subsp. nova, O. alba subsp. xanthostigma f. sineglandulosa f. nova, O. grossheimii f. pallescens f. nova, O. flava subsp. cicerbitae subsp. nova) werden beschrieben. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Orobanche benkertii sp. nova (Orobanchaceae Vent.) and further Orobanche species from the Northwest Caucasus mountains During two excursions of the first author to the northwest Caucasian area (Republic Adygeja) in 2001 and 2002 rich material of genus Orobanche L. has been collected. As a result of the determination of these specimens better knowledges especially about the lesser known and endemic species Orobanche gamosepala, O.grossheimii and O.inulae could be received and , besides , six new taxa (Orobanche benkertii sp. nova, O. laxissima sp. nova, O. alba subsp. xanthostigma subsp. nova, O. alba subsp. xanthostigma f. sineglandulosa f. nova, O. grossheimii f. pallescens f. nova, O. flava subsp. cicerbitae subsp. nova) are described. [source] Annual fishes of the genus Nothobranchius as a model system for aging researchAGING CELL, Issue 5 2005Tyrone Genade Summary Aging research in vertebrates is hampered by the lack of short-lived models. Annual fishes of the genus Nothobranchius live in East African seasonal ponds. Their life expectancy in the wild is limited by the duration of the wet season and their lifespan in captivity is also short. Nothobranchius are popular aquarium fishes and many different species are kept as captive strains, providing rich material for comparative studies. The present paper aims at reviving the interest in these fishes by reporting that: (1) Nothobranchius can be cultured, and their eggs stored dry at room temperature for months or years, offering inexpensive methods of embryo storage; (2) Nothobranchius show accelerated growth and expression of aging biomarkers at the level of histology and behaviour; (3) the species Nothobranchius furzeri has a maximum lifespan of only 3 months and offers the possibility to perform investigations thus far unthinkable in a vertebrate, such as drug screening with life-long pharmacological treatments and experimental evolution; (4) when the lifespan of different species is compared, a general correlation is found between wet season duration in their natural habitat and longevity in captivity; and (5) vertebrate aging-related genes, such as p66Shc and MTP, can be easily isolated in Nothobranchius by homology cloning. These fishes can become excellent models for aging studies. They can be employed to test the effects of experimental manipulation on aging at a pace comparable with that of Drosophila and to probe the effects of natural selection on the evolution of aging-related genes. [source] Conversion of Bioactive Borosilicate Glass to Multilayered Hydroxyapatite in Dilute Phosphate SolutionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2007Yadong Li The conversion of a bioactive borosilicate glass in aqueous phosphate solution was observed to produce vastly different reaction kinetics and hydroxyapatite (HA) microstructures, depending on whether the glass was reacted continuously or intermittently in the solution. Particles (150,300 ,m) of a borosilicate glass (designated H12) were reacted continuously or intermittently in 0.25M K2HPO4 solution with a starting pH value of 7.0 at 37°C. The conversion kinetics of the glass particles to HA were determined from weight loss measurements. Structural and compositional changes resulting from the conversion reaction were characterized using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, and Fourier transform infrared spectroscopy. For conversion experiments carried out intermittently (12,24 h intervals, followed by drying), faster reaction kinetics and a unique multilayered microstructure, consisting of alternating layers of HA and an amorphous SiO2 -rich material with nearly uniform thickness (2,3 ,m), were observed. On the other hand, particles reacted continuously in the phosphate solution for the same total time converted more slowly and produced a single HA layer. The kinetics and mechanism of forming HA under the intermittent and continuous reaction conditions are described and compared with those for bioactive silicate and borate glasses studied in previous work. [source] Non-stoichiometry and non-homogeneity in InNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005K. Scott Abstract It is shown that the wide variation of apparent band-gap observed for thin films nominally referred to as InN is strongly influenced by variations in the nitrogen:indium stoichiometry. InN samples grown by remote plasma enhanced chemical vapour deposition show a change in band-gap between 1.8 and 1.0 eV that is not due to the Moss-Burstein effect, oxygen inclusion or quantum size effects, but for which changes in the growth temperature result in a strong change in stoichiometry. Material non-homogenity and non-stoichiometry appear to be general problems for InN growth. Excess nitrogen can be present at very high levels and indium rich material is also found. This work shows that the extent of the Moss-Burstein effect will have to be reassessed for InN. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Second Republic for Italy?POLITICAL STUDIES REVIEW, Issue 1 2003Mark Donovan Radical change in the representative dimension of Italy's political system was expected to bring a transition to a ,Second Republic' in Italy. That has not happened. Nevertheless, after three consultations using the new parliamentary electoral system, studies focusing on the ,input' side of Italian politics are beginning to agree that substantial change has occurred. It is, however, too early to identify the extent of change in public administration and centre,local government relations, whilst even in parliament it is argued that consensual decision-making continued at least into the late 1990s. The impact of party system change on policy-making has thus been shown to be less direct than many expected, providing rich material for research into the relationship between institutional and policy change. Nevertheless, institutional change continues, particularly with regard to the decentralisation of government, and some studies suggest that this is the key to Italy's political transformation, rather than electoral reform or even change in the form of government. Still, the election of Italy's first right-wing majority government in 2001 may yet bring change in parliamentary practice and policy-making more generally. [source] Bioconversions of maize residues to value-added coproducts using yeast-like fungi,FEMS YEAST RESEARCH, Issue 2 2003Timothy D Leathers Abstract Agricultural residues are abundant potential feedstocks for bioconversions to industrial fuels and chemicals. Every bushel of maize (approximately 25 kg) processed for sweeteners, oil, or ethanol generates nearly 7 kg of protein- and fiber-rich residues. Currently these materials are sold for very low returns as animal feed ingredients. Yeast-like fungi are promising biocatalysts for conversions of agricultural residues. Although corn fiber (pericarp) arabinoxylan is resistant to digestion by commercially available enzymes, a crude mixture of enzymes from the yeast-like fungus Aureobasidium partially saccharifies corn fiber without chemical pretreatment. Sugars derived from corn fiber can be converted to ethanol or other valuable products using a variety of naturally occurring or recombinant yeasts. Examples are presented of Pichia guilliermondii strains for the conversion of corn fiber hydrolysates to the alternative sweetener xylitol. Corn-based fuel ethanol production also generates enormous volumes of low-value stillage residues. These nutritionally rich materials are prospective substrates for numerous yeast fermentations. Strains of Aureobasidium and the red yeast Phaffia rhodozyma utilize stillage residues for production of the polysaccharide pullulan and the carotenoid astaxanthin, respectively. [source] | ||||||||||