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排序方式: 共有2224条查询结果,搜索用时 15 毫秒
31.
RL Kincaid WJ Miller LS Jensen DL Hampton MW Neathery RP Gentry 《Canadian Metallurgical Quarterly》1976,55(5):1954-1957
Weight gains of younger broiler chicks were not reduced by up to 2400 p.p.m. added zinc fed to four weeks of age. Tissue zinc was not changed significantly by 600 or 1200 p.p.m. supplemental dietary zinc, but at 2400 p.p.m. added zinc, blood, kidney, and liver zinc were significantly elevated (P less than 0.05). In the heart, zinc was not affected by the added dietary zinc but increased over time with all diets. Unlike the calf and weanling pig, the metabolism of zinc in the young chick does not appear to change appreciably with increasing maturity. Thus, the homeostatic control mechanisms of the young chick are effective for up to 1200 p.p.m. dietary zinc, but are partially overcome by 2400 p.p.m. added dietary zinc. 相似文献
32.
A microplate-microtubule array was observed in Anabaena sp. (B-378). This structure consists of an arched plate, about 8 nm thick, and various microtubules, 12 nm in diameter and 50 nm long, arranged in rows. The microtubules project at right angles from one side of the plate into the cytoplasm or towards the plasma membrane. Up to twelve microplate-microtubule arrays were observed in a single section of a cell. Microfilaments, about 2.8 nm in diameter and of undetermined length, were observed in four isolates of Anabaena. The microfilaments were always found in bundles, nwhich varied in size, up to 0.63 mum across and 0.91 mum long. Microtubules, 10 nm in diameter and about 150 nm in length, were observed associated with one facet of polyhedral bodies in 8 out of 20 isolates of Anabaena. The microtubules occurred in groups of up to 20 or more, and were always oriented with the long axis parallel to the facet of a polyhedral body. In cross section, the microtubules had an electron transparent lumen 5 nm wide and a wall 2.5 nm thick. These structures are compared to previously described microtubules and microfilaments. 相似文献
33.
The nature and extent of social worker's involvement in regional health planning agencies was the subject of the nationwide study reproted here. Social work proved to be more heavily represented on the professional staffs of these agencies than any other discipline. This was just one of the findings that can help shape the profession's response to the possibilities this new field represents. 相似文献
34.
Cilioretinal arteries. A study based on review of stereo fundus photographs and fluorescein angiographic findings 总被引:1,自引:0,他引:1
The incidence of cilioretinal arteries in 2,000 eyes of 1,000 consecutive patients was determined by review of stereo color fundus photographs and fluorescein angiographs. One or more cilioretinal arteries were present in 49.5% of all patients or in 32.1% of the eyes. The arteries occurred bilaterally in 14.6% and contributed to some portion of the macular circulation in 18.7% of the patients. A great deal of variability of size, number, and distribution of cilioretinal vessels was observed. Prior studies that were based on direct visualization of the fundus have reported cilioretinal arteries in 7% to 29.6% of patients examined. Careful review of stereo fundus photographs and early phase fluorescein angiographs aided in the observation of these vessels that might otherwise have been unrecognized. We believe the method of review accounts for the high incidence of cilioretinal arteries in our series. 相似文献
35.
The thermodynamic properties of food as a function of pressure and temperature are essential for modeling high-pressure processes. Sound velocity measurements in liquids at high pressure conditions are particularly interesting because they allow for deriving other properties such as the specific heat capacity or thermal expansion coefficient which are difficult to measure. By other means, in this work, the sound velocity was measured in tomato paste at high pressures with a purposed designed acoustic cell. The measurements were made in a wide range of pressures and temperatures from 0.1 to 350 MPa and from 0 to 50 °C, respectively. The sound velocity was directly measured with an accuracy of 0.1% using the transmission technique with piezoelectrics operating at 2 MHz. Thereafter, the isentropic compressibility coefficient of tomato paste was calculated from experimental data. Specific heat capacity and thermal expansion coefficient were also obtained through a software algorithm. 相似文献
36.
A bibliographic search yielded a set of empirical equations that constitute an easy method for the calculation of some thermophysical properties of both liquid water and ice I, properties that are involved in the modeling of thermal processes in the high-pressure domain, as required in the design of new high-pressure food processes. These properties, closely interrelated in their physical derivation and experimental measurement, are specific volume, specific isobaric heat capacity, thermal expansion coefficient, and isothermal compressibility coefficient. Where no single equation was found, an alternative method for calculation is proposed. Keeping in mind the intended applications and considering the availability of both experimental data and empirical equations, the limits for the set of equations where set in -40 to 120 degrees C and 0 to 500 MPa for liquid water and -30 to 0 degrees C and 0 to 210 MPa for ice I. The equations and methods selected for each property are described and their results analyzed. Their good agreement with many existing experimental data is discussed. In addition, the routines implemented for the calculation of these properties after the described equations are made available in the public domain. 相似文献
37.
Miguel Barrueco María José Otero Luis Palomo Carlos Jiménez-Ruiz Miguel Torrecilla Pedro Romero Juan Antonio Riesco 《Nicotine & tobacco research》2005,7(3):335-342
This multicenter, community-based, prospective, longitudinal study evaluated the safety of nicotine replacement therapy (NRT), bupropion, and combined therapy of NRT and bupropion for smokers seeking to quit, when these therapies were used under real-world conditions following a smoking cessation program. Participants were smokers aged 18 years or older who attended five smoking cessation clinics. Evaluations were made at 15, 30, 60, and 90 days. We investigated the possible existence of adverse effects as well as the severity of each adverse effect and its influence on the treatment course. The study included 904 smokers: 370 received NRT, 413 received bupropion, and 121 received combined therapy. At 15, 30, 60, and 90 days, adverse effects were reported by 43.8%, 33.1%, 22.3%, and 5.7% of subjects, respectively. Adverse effects were significantly more frequent in subjects receiving combined therapy or bupropion alone than in NRT-treated subjects at the 15-, 30-, and 60-day follow-ups. A total of 83 smokers (9.3%) withdrew from treatment and 116 (12.8%) stopped temporarily because of adverse effects. No differences were found in the percentages of discontinuation among the different treatment options. Adverse effects rarely were severe (n=10). Nevertheless, 41 subjects (4.5%) discontinued drug therapy indefinitely and 55 (6.1%) discontinued it temporarily because of mild adverse effects. Pharmacological therapies for smoking cessation are safe as long as they are appropriately prescribed and supervised by clinicians according to clinical practice guidelines. Adverse effects are primarily mild. Nonetheless, mild adverse effects may be perceived by patients as a serious enough problem to cause them to discontinue treatment. 相似文献
38.
González-Fandos ME Sierra ML García-López ML Otero A Sanz J Moreno B 《Meat science》1996,43(3-4):255-263
The effect of meat cultures (non lactic acid bacteria) on the growth and production of enterotoxins and thermonuclease by Staphylococcus aureus was studied. Micrococcus varians did not affect growth nor the synthesis of metabolites. Levels of enterotoxins A, B and D produced by the respective S. aureus strains were reduced by S. xylosus, S. saprophyticus and S. carnosus. The two latter species prevented production of enterotoxin C1 and S. xylosus markedly reduced the amount produced. The three coagulase-negative staphylococci showed little inhibitory effect on the growth of S. aureus. Penicillium nalgiovense did not show inhibitory activity against the four S. aureus strains. Debaryomyces hansenii slightly inhibited growth of the enterotoxin A-producing strain, but reduced enterotoxin synthesis at 30 °C. Thermonuclease was detected whenever enterotoxins were detected though the influence of the effector organism was dependent on the test strain. 相似文献
39.
Miguel A. Otero María del C. Vasallo Olga Verdecia Víctor Fernndez Dionisio Betancourt 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1996,67(1):67-71
A process for the preparation of yeast-derived food additives was developed. The four products obtained, yeast protein concentrate (YPC), cell-wall protein (CWP), semi-pure glucomannan (SPG) and yeast extract, compared well with similar products, present in the current market, with respect to functional properties. YPC and CWP exhibited improved water-holding and oil-binding properties over those of soy-protein isolate (SPI). The emulsifying capacity was very close to that observed in commercial samples. A one-step alkaline extraction enhanced the functional properties of primary yeast glycan to match traditional food hydrocolloid sources. SPG showed oil-binding properties significantly greater than commercial glucomannan. 相似文献
40.
Manuel Gacitúa Alexander Carreo Rosaly Morales-Guevara Dayn Pez-Hernndez Jorge I. Martínez-Araya Eyleen Araya Marcelo Preite Carolina Otero María Macarena Rivera-Zaldívar Andrs Silva Juan A. Fuentes 《International journal of molecular sciences》2022,23(5)
Searching for adequate and effective compounds displaying antimicrobial activities, especially against Gram-positive bacteria, is an important research area due to the high hospitalization and mortality rates of these bacterial infections in both the human and veterinary fields. In this work, we explored (E)-4-amino-3-((3,5-di-tert-butyl-2-hydroxybenzylidene)amino) benzoic acid (SB-1, harboring an intramolecular hydrogen bond) and (E)-2-((4-nitrobenzilidene)amino)aniline (SB-2), two Schiff bases derivatives. Results demonstrated that SB-1 showed an antibacterial activity determined by the minimal inhibitory concentration (MIC) against Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus (Gram-positive bacteria involved in human and animal diseases such as skin infections, pneumonia, diarrheal syndrome, and urinary tract infections, among others), which was similar to that shown by the classical antibiotic chloramphenicol. By contrast, this compound showed no effect against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, and Salmonella enterica). Furthermore, we provide a comprehensive physicochemical and theoretical characterization of SB-1 (as well as several analyses for SB-2), including elemental analysis, ESMS, 1H and 13C NMR (assigned by 1D and 2D techniques), DEPT, UV-Vis, FTIR, and cyclic voltammetry. We also performed a computational study through the DFT theory level, including geometry optimization, TD-DFT, NBO, and global and local reactivity analyses. 相似文献