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951.
A new compound, named (S)-α-acetylamino-β-(3-indole)propano1 (1) was isolated, along with two known compounds teleocidin B 1 and emycin B from culture broth of a streptomycete strain YIM33176 (streptomyces pleomorphus). The structure of 1 was determined by detailed spectroscopic investigation. 相似文献
952.
Jürgen Bokowski Simon King Susanne Mock Ileana Streinu 《Discrete and Computational Geometry》2005,33(4):645-668
We present a new proof of the Topological Representation Theorem for
oriented matroids in the general rank case. Our proof is based on an
earlier rank 3 version. It uses hyperline sequences and the
generalized Schonflies theorem. As an application, we show that one can read off oriented matroids
from arrangements of embedded spheres of codimension one, even if wild
spheres are involved. 相似文献
953.
Susanne Saminger-Platz 《Indagationes Mathematicae》2008,19(1):135-150
Smallest and largest possible extensions of triangular norms on bounded lattices are discussed. As such ordinal and horizontal sum like constructions for t-norms on bounded lattices are investigated. Necessary and sufficient conditions for the lattice guaranteeing that the extension is again a t-norm are revealed. 相似文献
954.
955.
Alois W. Schmalwieser Veronika T. Schmalwieser Susanne S. Schmalwieser 《Photochemistry and photobiology》2019,95(4):1068-1075
Clothing is one of the main influencing factors for personal ultraviolet radiation (UVR) exposure. Despite that, little attention was put on this topic till now. In this study, the clothing habits of young females have been investigated in dependence of meteorological conditions. Observations were made from spring to autumn during daylight in the urban region of Vienna, Austria. For this, a scheme dividing the body into six different sections was developed as well as a coding scale that corresponds to the different garments and indicates the body sites that are exposed. It was found that air temperature is the dominating factor for exposure. With increasing temperature, the first area of the body to be exposed to solar UVR is, aside from face and hands, the décolleté, followed by nape, ankles, instep and forearms. Observations further indicate that the frequency of people's being outdoors decreases significantly at temperatures higher than 30°C. This paper provides detailed frequency distributions of uncovered body sites in dependence of temperature. These can be used together with measurements of temperature and UVR to calculate the relative exposure at any time and at many locations, and could help to explain the body distribution of UVR caused skin alterations. 相似文献
956.
Dr. Bin Li Dr. Susanne Bauer Dr. Michael Seidl Prof. Dr. Alexey Y. Timoshkin Prof. Dr. Manfred Scheer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(60):13714-13718
The pnictogenyl Group 13 compounds (Dipp2Nacnac)M[E(SiMe3)2]Cl and (Dipp2Nacnac)M(EH2)2 (Dipp2Nacnac=HC[C(Me)N(Ar)]2, Ar: Dipp=2,6-iPr2C6H3; M=Al, Ga, In; E=P, As) were successfully synthesized. The salt metathesis between (Dipp2Nacnac)MCl2 and LiE(SiMe3)2 only led to monosubstituted compounds (Dipp2Nacnac)M[E(SiMe3)2]Cl [E=P, M=Ga( 1 ), In ( 2 ); E=As, M=Ga ( 3 ), In ( 4 )], regardless of the stoichiometric ratios used. In contrast to the steric effect of the SiMe3 groups in 1 – 4 , the reactions of the corresponding halides with LiPH2⋅DME (or KAsH2) facilely yielded the dipnictogenide compounds (Dipp2Nacnac)M(EH2)2 (E=P, M=Al ( 5 ), Ga ( 6 ), In ( 7 ); E=As, M=Al ( 8 ), Ga ( 9 )), avoiding the use of flammable and toxic PH3 and AsH3 for their synthesis. The compounds 5 – 9 are the first examples of monomeric Group 13 diphosphanides and diarsanides in which the metal center is bound to two terminal PH2 and AsH2 groups, respectively. In contrast to the successful synthesis of the indium diphosphanide (Dipp2Nacnac)In(PH2)2, the reaction of (Dipp2Nacnac)InCl2 with KAsH2 led to an indium mirror due to the instability of the target product. 相似文献
957.
958.
Eight selected experiments intend at demonstrating synthesis, properties, function and application of nanomaterials. The reader should be stimulated to “Do‐it‐yourself” experiments at schools as well as at universities. In detail the experiments are: (1) Light scattering of suspensions, (2) Self‐made opals, (3) Quantum‐Size effects and red gold, (4) Surfaces and surface functionalization, (5) Pyrophoric iron, (6) Superparamagnetism and magnetic liquids, (7) TiO2 and dye‐sensitized solar cells as well as (8) Phosphors and luminescent biomarkers. All experiments are organized to allow for simple and fast implementation, although this implies a certain limitation regarding the quality of the material properties in detail. Altogether, the interest in nanosciences and nanotechnology should be aroused as well as the curiosity to learn even more. 相似文献
959.
960.
Voss S Zimmermann DJ Hesse A von Unruh GE 《Isotopes in environmental and health studies》2004,40(3):199-205
Calcium oxalate (CaOx) urolithiasis is the most common urinary stone disease (70-75 % of all stones consist of CaOx in countries with western diet). Oxalate is the most lithogenic substance in CaOx crystallisation in urine. Oxalate is either synthesized within the body or absorbed from food. As oxalate is not metabolized in the human body, it appears unchanged in urine. Conventional analysis methods cannot distinguish between endogenous and exogenous oxalate. Our [13C2]oxalate absorption test enabled measurement of intestinal oxalate absorption and quantification of the influence of Ca- and Mg-supplementation on it. The effects of the oral administration of these supplements were compared in order to obtain valid data for recommendations for CaOx urolithiasis patients. A 10 mmol supplement of both ions decreased the oxalate absorption significantly, calcium being more than twice as effective. 相似文献