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排序方式: 共有553条查询结果,搜索用时 31 毫秒
91.
BM Gerlach TA Houser LC Hollis MD Tokach JC Nietfeld JJ Higgins GA Anderson BL Goehring 《Meat science》2012,92(4):805-807
Nursery-age pigs (n=198) were used to evaluate the difference in abscess formation at needle-free jet and conventional needle-and-syringe injection sites. Needle-free jet injection was used to administer injections in the neck and ham on one side of the animal whereas needle-and-syringe was used for neck and ham injections on the opposite side. Immediately prior to injection, the injection site surfaces were contaminated with an inoculum of Arcanobacterium pyogenes. Each pig was humanely euthanized 27 or 28days after injections. Histopathological results showed that needle-free jet injection was associated with more abscesses than needle-and-syringe injection at both neck (P=0.0625) and ham (P=0.0313) injection sites. Out of 792 injection sites, only 13 abscesses were observed, with 12 of those present at needle-free jet injection sites. Needle-free jet injection may increase the occurrence of injection site abscesses that necessitate carcass trimming at pork processing plants. 相似文献
92.
Arved C. Hübler Maxi Bellmann Georg C. Schmidt Stefan Zimmermann André Gerlach Christian Haentjes 《Organic Electronics》2012,13(11):2290-2295
We report on the first fully mass printed large-area piezoelectric loudspeakers on paper. All functional layers were printed by means of flexography, alternatively screen and stencil printing, on conventional paper without any surface modification. We used polymers for the electrodes (poly(3,4-ethylendioxythiophene)/poly(4-styrenesulfonate, PEDOT:PSS)) as well as the piezoelectric layer (poly(vinylidene fluoride-trifluorethylene), P(VDF-TrFE)). It could be demonstrated that low-cost devices for mass markets can be realized successfully with the developed technology and process. Besides technical challenges, electrical and acoustic properties of printed speakers are investigated, taking the mechanical properties of the substrate and size of the active piezoelectric area into account. A sound pressure level up to 80 dB could be achieved. 相似文献
93.
Benjamin Hahn Till Vallée Bernhard Stamm Yves Weinand 《Holz als Roh- und Werkstoff》2014,72(2):229-241
Research on friction welded wood-to-wood connections has shown high potential for further development regarding the industrial application of timber construction. This paper addresses the question to which extent welding of wood can be applied to fabrication of cross-laminated timber panels (CLT). Those panels can be used as wall elements, in which load transfer occurs by transmission of moments and shear stresses. For this purpose, experimental investigations on friction welded L-shaped specimens were carried out. The welded bond between the boards, arranged perpendicularly to their fibre directions, represents points of intersection of those CLT panels. The results allowed for (a) the determination of a fracture mechanism of welded timber connections under torsion, (b) the definition of a set of design parameters influencing the resulting joint strength and (c) the comparison between the performance of welded timber joints and those of commonly glued alternatives. The experimental investigations were compared to results obtained by numerical modelling, thus allowing a probabilistic strength prediction algorithm for predicting the joint capacity as a function of the surface size. 相似文献
94.
Till C.; Ghassemi R.; Aubert-Broche B.; Kerbrat A.; Collins D. L.; Narayanan S.; Arnold D. L.; Desrocher M.; Sled J. G.; Banwell B. L. 《Canadian Metallurgical Quarterly》2011,25(3):319
Objective: Brain MRI measures were correlated with neuropsychological function in 35 pediatric-onset multiple sclerosis (MS) patients and 33 age- and sex-matched healthy controls. Method: Mean age of MS patients was 16.3 ± 2.3 years with average disease duration of 4.3 ± 3.1 years. Cortical gray matter, thalamic, and global brain volumes were calculated for all participants using a scaling factor computed using normalization of atrophy method to normalize total and regional brain volumes for head size. T1- and T2-weighted lesion volumes were calculated for MS patients. Results: Cognitive impairment (CI) was identified in 29% of the MS cohort. Cognitive deficits predominantly involved attention and processing speed, expressive language, and visuomotor integration. Relative to controls, the MS group showed significantly lower thalamic volume (p p p p 相似文献
95.
Schüffler A Liermann JC Opatz T Anke T 《Chembiochem : a European journal of chemical biology》2011,12(1):148-154
Feeding experiments with the ascomycete Allantophomopsis lycopodina indicated that the potent fungistatic allantofuranone is biosynthesized from phenylalanine. Further experiments with synthetic precursors gave evidence that the naturally occurring polyporic acid serves as a key intermediate in the biosynthesis. In addition to the formation of allantofuranone, its abiotic and metabolic degradation were investigated. 相似文献
96.
Michael Bond Wayne Croft Richard Tyson Till Bretschneider Graham Ladds 《Yeast (Chichester, England)》2013,30(4):145-156
Ras signalling is central to fundamental and diverse cellular processes. In higher eukaryotes ras signalling is highly complex, involving multiple isoforms, regulatory proteins and effectors. As a consequence, the study of ras activity in mammalian systems presents a number of technical challenges. The model organism Schizosaccharomyces pombe has previously proved a key system for the study of human signalling components and provides an ideal model for the study of ras, as it contains just one ras protein (Ras1p), which is non‐essential and controls a number of downstream processes. Here we present data demonstrating the quantitative analysis of three distinct Ras1‐related signalling outputs, utilizing the three most abundant human ras isoforms, H‐Ras, N‐Ras and K‐Ras4B, in Sz. pombe. Further, we have characterized the localization of these three human ras isoforms in Sz. pombe, utilizing quantitative image analysis techniques. These data indicate that all three human ras isoforms are functional in fission yeast, displaying differing localization patterns which correlate strongly with function in the regulation of pheromone response and cell shape. These data demonstrate that such yeast strains could provide powerful tools for the investigation of ras biology, and potentially in the development of cancer therapies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
97.
Christina A. Müller Beneeta Akkapurathu Till Winkler Svenja Staudt Werner Hummel Harald Grger Ulrich Schwaneberg 《Advanced Synthesis \u0026amp; Catalysis》2013,355(9):1787-1798
A novel concept for the direct oxidation of cycloalkanes to the corresponding cyclic ketones in a one‐pot synthesis in water with molecular oxygen as sole oxidizing agent was reported recently. Based on this concept we have developed a new strategy for the double oxidation of n‐heptane to enable a biocatalytic resolution for the direct synthesis of heptanone and (R)‐heptanols in a one‐pot reaction. The bicatalytic cascade employs an NADH driven P450 BM3 monooxygenase variant (WTNADH, 19A12NADH or CM1NADH) and an (S)‐enantioselective alcohol dehydrogenase (RE‐ADH). In the initial step n‐heptane is hydroxylated under consumption of NADH to produce (R/S)‐heptanol. In the second oxidation step the (S)‐heptanol enantiomers are transformed to the corresponding ketones, reducing and thereby regenerating the cofactor. Characterization of initial hydroxylation step revealed high turnover frequencies (TOF) of up to 600 min−1, as well as high coupling efficiencies using NADH as cofactor (up to 44%). In the cascade reaction a nearly 2‐fold improved product formation was achieved, compared to the single hydroxylation reaction. The total product concentration reached 1.1 mM, corresponding to a total turnover number (TTN) of 2500. Implementation of an additional cofactor regeneration system (D ‐glucose/glucose dehydrogenase) enabled a further enhancement in product formation with a total product concentration of 1.8 mM and a TTN of 3500. 相似文献
98.
A generalized likelihood ratio test (GLRT) for the adaptive detection of a target or targets that are Doppler-shifted and distributed in range is derived. The unknown parameters associated with the hypothesis test are the complex amplitudes in range of the desired target and the unknown covariance matrix of the additive interference, which is assumed to be characterized as complex zero-mean correlated Gaussian random variables. The target's or targets' complex amplitudes are assumed to be distributed across the entire input data block (sensor × range). The unknown covariance matrix is constrained to have the reasonable form of the identity matrix (the internal noise contribution) plus an unknown positive semidefinite (psdh) matrix (the external interference contribution). It is shown via simulation for a variety of interference scenarios that the new detector has the characteristic of having a bounded constant false alarm rate (CFAR), i.e., for our problem, the probability of false alarm PF for a given detection threshold is bounded by the PF that results when no external interference is present. It is also shown via simulation that the new detector converges relatively fast with respect to the number of sample vectors K necessary in order to achieve a given probability of detection PD 相似文献
99.
J. Osenbach A. Amin M. Bachman F. Baiocchi D. Bitting D. Crouthamel J. DeLucca D. Gerlach J. Goodell C. Peridier M. Stahley R. Weachock 《Journal of Electronic Materials》2009,38(2):303-324
The thermal stability of flip-chip solder joints made with trilayer Al/Ni(V)/Cu underbump metalization (UBM) and eutectic
Pb-Sn solder connected to substrates with either electroless Ni(P)-immersion gold (ENIG) or Pb-Sn solder on Cu pad (Cu-SOP)
surface finish was determined. The ENIG devices degraded more than 50 times faster than the Cu-SOP devices. Microstructural
characterization of these joints using scanning and transmission electron microscopy and ion beam microscopy showed that electrical
degradation of the ENIG devices was a direct result of the conversion of the as-deposited Ni(V) barrier UBM layer into a porous
fine-grained V3Sn-intermetallic compound (IMC). This conversion was driven by the Au layer in the ENIG surface finish. No such conversion
was observed for the devices assembled on Cu-SOP surface finish substrates. A resistance degradation model is proposed. The
model captures changes from a combination of phenomena including increased (1) intrinsic resistivity, (2) porosity, and (3)
electron scattering at grain boundaries and surfaces. Finally, the results from this study were compared with results found
in a number of published electromigration studies. This comparison indicates that degradation during current stressing in
the Pb-Sn bump/ENIG system is in part due to current-crowding-induced Joule heating and the thermal gradients that result
from localized Joule heating. 相似文献
100.
Razan Alaneed Yury Golitsyn Till Hauenschild Markus Pietzsch Detlef Reichert Jrg Kressler 《Polymer International》2021,70(1):135-144
A highly efficient approach for the synthesis of polyester‐based networks via aza‐Michael addition of primary amines to α,β‐unsaturated (vinyl) end groups of poly(glycerol adipate) (PGA) was achieved. By acylation of PGA with 6‐(Fmoc‐amino)hexanoic acid side chains via Steglich esterification, protected amine‐functionalized PGA was obtained. This was followed by the removal of fluorenylmethyloxycarbonyl (Fmoc) protecting groups and the synthesis of PGA‐based networks under catalyst‐free conditions. The successful conjugate addition of primary amines to vinyl end groups and network formation were confirmed using 13C magic angle spinning NMR and Fourier transform infrared spectroscopy. Network heterogeneity and defects were quantitatively investigated using 1H double‐quantum NMR spectroscopy. Finally, a hydrogel was prepared with potential biomedical applications. 相似文献