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排序方式: 共有2028条查询结果,搜索用时 15 毫秒
1.
FJ Grommers 《Canadian Metallurgical Quarterly》1993,118(6):207-212
The intrinsic value of animals and their place in human society influence veterinary practice. The role-responsibility of the veterinarian is under pressure of practical circumstances, client requests and constraints of breeding and management systems. A reflection on human needs as related to the intrinsic value and welfare of animals, is required inside and outside the profession. It is in the interest of life to think and act out of total ecological concepts. In order to be better prepared to deal with ethical problems in practice, students should receive adequate training. The assumed value-free research and the need for outside financial support are a hindrance for research projects that aim at sustainability of human and animal life. It is concluded that the profession needs a philosophy about her objectives. 相似文献
2.
Yong-Seo Park Seong-Gook Kang Alma Leticia Martinez Ayala Olga Martín-Belloso Shela Gorinstein 《LWT》2006,39(7):748-755
Fresh persimmons were subjected to two different processes: sun-drying during 1 month and dehydration at 60 °C during 12 h. To assess the effect of this process on nutritional and health-related properties of persimmons dietary fibers, minerals, trace elements, polyphenols and the total radical scavenging activities (TRSAs) were determined before and after processing. It was found that the contents of dietary fibers, minerals and trace elements in fresh and dried persimmons fruits were comparable. Total polyphenols in fresh persimmons was higher than in dried fruits (1.3 vs. 0.9 and 0.8 mg/100 g FW, respectively) and percentage of inhibition was higher than in dried fruits (70% vs. 59% and 55% and 58% vs. 53% and 46% for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) [ABTS] radicals, respectively (P>0.05 in all cases). In conclusion: (1) the differences in the contents of dietary fibers, minerals and trace elements in fresh and dried persimmons are not significant; (2) the contents of polyphenols and the level of the TRSA are higher in fresh persimmons than in dried fruits; however, both variables are also high in dried persimmons; (3) when fresh fruits are not available, proper dried persimmons could be used as a valuable substitute. 相似文献
3.
Paola Ayala Hidetsugu Shiozawa Katrien De Blauwe Yasumitsu Miyata Rolf Follath Hiromichi Kataura Thomas Pichler 《Journal of Materials Science》2010,45(19):5318-5322
Carbon based structures have been widely studied by X-ray absorption (XAS), also called NEXAFS, which is a very useful bulk probing method that allows examining the unoccupied density of states (DOS) and the site selective bonding environment. Two very well known spectral features in the XAS core level spectrum are the σ* and π* bands, and both have been analyzed in several studies for graphitic-like systems. However, among all the carbon materials, the unique one-dimensional electronic properties attributed to single-walled carbon nanotubes (SWCNTs) exhibit features that reveal clearly their electronic structure in the core level XAS spectrum. In this article, we outline the C1s response in XAS, which is related to the DOS of the conduction band in SWCNTs and its fine structure, revealed by experiments performed on metallicity-sorted SWCNT material. The progress in the identification of changes in the site selective conduction band electronic structure with XAS is discussed in detail. 相似文献
4.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), and benz[a]anthracene (BA) highly induce cytochrome P4501A1, determined by aryl hydrocarbon hydroxylase (AHH) activity, in human hepatoma HepG2 cells within 24 h. AHH activity induced by TCDD and TCDF persists for at least 48 h. In contrast, AHH activity induced by BA rapidly declines, although the amounts applied are 4-5 orders of magnitude higher than those of TCDD or TCDF. AHH induction in HepG2 cells differs from that in rat hepatoma cells H4IIEC3/T in two aspects: (1) HepG2 cells are 20 times less sensitive to the test compounds than H4IIEC3/T cells. (2) TCDF-induced AHH activity does not persist in the rat cells. The results suggest that human HepG2 cells, because of their low sensitivity, are inferior to rat H4IIEC3/T cells for determining TCDD equivalents in environmental samples. They may be useful for investigating species dependent differences in the toxicokinetics of individual polyhalogenated aromatic hydrocarbon congeners. 相似文献
5.
6.
Neurotensin (NT) was isolated from an extract of the intestine of the cane toad, Bufo marinus and its primary structure established as: pGlu-Ala-Ile-Val-Ser-Lys-Ala-Arg-Arg-Pro-Tyr-Ile-Leu. This amino acid sequence shows five substitutions (Leu2 --> Ala, Tyr3 --> Ile, Glu4 --> Val, Asn5 --> Ser, and Pro7 --> Ala) compared with bovine NT. Synthetic Bufo NT (pD2 = 8.05 +/- 0.28) was equipotent and equally effective as bovine NT (pD2 = 8.24 +/- 0.38) in producing spasmogenic contraction of isolated segments of toad small intestine. However, the maximum response produced by Bufo NT was only 35 +/- 2% of that produced by substance P. The potencies, but not the maximum responses, to Bufo and bovine NT were significantly (p < 0.05) attenuated by pre-treatment with atropine but neither parameter was significantly diminished by tetrodotoxin and indomethacin. The data suggest that the action of NT involves interaction with receptors on toad intestinal smooth muscle that recognize the C-terminal region of NT (residues 8-13) that has been fully conserved during evolution of tetrapods. Contractile activity is mediated, at least in part, by release of acetylcholine. 相似文献
7.
In this study, we investigated the activity of pre-sulfated 1%Pt–2%Sn/γ–Al2O3 on the catalytic abatement of the combustion emissions of three fuels: pure diesel E(0), pure bioethanol E(100) and bioethanol blended diesel containing 10% bioethanol E(10). The emissions generated, by each blend combustion, were conducted continuously to the catalyst sample. The catalytic activity was determined by following the evolution of the outflow emissions concentrations by FTIR gas spectroscopy as a function of the catalyst temperature. Results showed that the addition of bioethanol to diesel may be necessary to enhance the catalytic oxidation of diesel unburned hydrocarbons and particulate matter on pre-sulfated 1%Pt–2%Sn/γ–Al2O3. 相似文献
8.
9.
Ayala Gancz Yekaterina Zueva Orly E. Weiss Roni M. Hendler Rafael Minnes Danny Baranes 《Israel journal of chemistry》2020,60(5-6):586-592
Inflammatory and immunogenic response to foreign bodies presents a challenge in the use of biomaterials as implants for tissue restoration. Therefore, there is a need to understand the interactions between such implants and the blood. One such material, currently in clinical use for bone replacement in humans, is the skeleton of corals, in the form of crystalline aragonite. This biomaterial has been shown to impart a protective and supportive influence on several types of cells ex vivo. The carbonate skeleton activates secretion in phagocytes in vitro, however its effects on these cells in the blood, and on the process of phagocytosis itself, remain unknown. Using 1–500 μm particles of coral skeleton, we show that these particles bind blood proteins and alter the leukocyte population, reducing the proportion of granulocytes by more than 3-fold with no effect on the proportion of monocytes. In addition, the presence of coral skeleton in the blood causes a reduction in phagocytosis. Specifically, we observed a decrease in the percentage of phagocytic cells by 27 % in the granulocytes and by 73 % in monocyte family, as well as a 41.6 % reduction in the MFI of granulocytes, but with no such effect on monocytes. Taken together, the results suggest that the coral skeleton biomaterial may act as a strong, promotive scaffold for tissue regeneration due to its ability to reduce its rejection by inflammatory reactions such as phagocytosis. 相似文献
10.
Molecular modeling of immunoglobulin light chains implicates hydrophobic residues in non-amyloid light chain deposition disease 总被引:3,自引:0,他引:3
Deret S; Chomilier J; Huang DB; Preud'homme JL; Stevens FJ; Aucouturier P 《Protein engineering, design & selection : PEDS》1997,10(10):1191-1197
Light chain deposition disease is a severe complication of certain
immunoproliferative disorders, due to the secretion of a monoclonal light
chain which precipitates close to basement membranes of several tissues. A
kappa isotype restriction and an unusual frequency of a variable region
subgroup (VkappaIV) suggest that precise structural features govern the
propensity of pathogenic light chains to precipitate in extracellular
spaces. We studied primary structures of light chains from six patients
with light chain deposition disease in comparison with light chains from
other pathological conditions. Sequence alignment revealed the presence of
certain amino acids only in light chain deposition disease, in particular
non-polar replacing hydrophilic residues. To determine the role of these
residues, structures of the variable domain from four kappa chains
belonging to VkappaI and VkappaIV subgroups responsible for deposition
disease were modeled using known immunoglobulins as templates. The most
evident structural features shared by all pathogenic light chains were
hydrophobic residues exposed to the solvent in complementarity determining
regions 1 or 3. In contrast to immunoglobulin light chain- related
amyloidosis, where deposition of organized material might be due to
electrostatic interactions between light chain dimers, hydrophobic
interactions could enhance amorphous precipitation in non- amyloid light
chain deposition disease.
相似文献