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排序方式: 共有293条查询结果,搜索用时 15 毫秒
91.
A double-well CMOS concept well suited to conventional and state-of-the-art isolation techniques is presented. Sufficient field doping is achieved by solely distributing the well drive-in thermal budget before and after field oxidation. Segregation effects, in particular dopant loss in the p-well, are compensated. At the same time the body factor and parasitic capacitances are kept low. The split drive-in approach makes channel-stop implants and corresponding lithography steps superfluous. The field doping adjustment is self-aligned, a very significant advantage in submicrometer regime processing 相似文献
92.
93.
Zampronio CG Giannakopulos AE Zeller M Bitziou E Macpherson JV Derrick PJ 《Analytical chemistry》2004,76(17):5172-5179
Electrospray ionization (ESI) is extensively used in the analysis of biological compounds; yet some fundamental properties of this technique are not completely understood. It is widely recognized that care should be exercised when noncovalent complexes are being studied by ESI, since weak noncovalent binding can be broken or formed during the desolvation process. In the present work, spectra from the noncovalent complex, vancomycin/diacetyl-L-lysyl-D-alanyl-D-alanine, obtained from ESI and from nanoelectrospray ionization (nanoESI), have been compared. The results indicated that the milder desolvation conditions arising as a result of the smaller sizes of droplets produced in the nanoESI source attenuated effects upon weak bonds in the desolvation process. The association constant values calculated from the relative peak intensities suggest that, when using ESI, the analyzed noncovalent complex dissociated in the condensed phase during the spraying process. The influences of experimental parameters such as tip diameter and coating for nanoESI needles were investigated. Principal component analysis, a multivariate analysis method, was applied to achieve a better evaluation of the spectra obtained using different needle diameters and coatings for the analysis of the noncovalent complex vancomycin/diacetyl-L-lysyl-D-alanyl-D-alanine. It was found that 2-microm tip diameter resulted in more reproducible spectra than the larger tip diameters tested (6-20 microm). 相似文献
94.
Aroua A Besançon A Buchillier-Decka I Trueb P Valley JF Verdun FR Zeller W 《Radiation protection dosimetry》2004,111(3):289-295
This work aims at establishing a set of diagnostic reference levels (DRLs) for various types of examinations performed in diagnostic and interventional radiology. The average doses for 257 types of radiological examinations were established during the 1998 nationwide survey on the exposure of the Swiss population by radiodiagnostics. They were calculated using appropriate dosimetric models and average technical parameters. The DRLs were derived from the average doses using a multiplying factor of 1.5. The DRLs obtained were rounded and compared to the data reported in the literature. The results are in most cases comparable to the DRLs determined by the 3rd-quartile method. These discrepancies registered in some cases, particularly for complex examinations, can be explained by significant differences in the protocols and/or the technical parameters used. A set of DRLs is proposed for a large number of examinations to be used in Switzerland as temporary values until a national dosimetric database is set up. 相似文献
95.
Marie Josse Eve Rigal Nathalie Rosenblatt-Velin Luc Rochette Marianne Zeller Charles Guenancia Catherine Vergely 《International journal of molecular sciences》2020,21(24)
Nutritional environment in the perinatal period has a great influence on health and diseases in adulthood. In rodents, litter size reduction reproduces the effects of postnatal overnutrition in infants and reveals that postnatal overfeeding (PNOF) not only permanently increases body weight but also affects the cardiovascular function in the short- and long-term. In addition to increased adiposity, the metabolic status of PNOF rodents is altered, with increased plasma insulin and leptin levels, associated with resistance to these hormones, changed profiles and levels of circulating lipids. PNOF animals present elevated arterial blood pressure with altered vascular responsiveness to vasoactive substances. The hearts of overfed rodents exhibit hypertrophy and elevated collagen content. PNOF also induces a disturbance of cardiac mitochondrial respiration and produces an imbalance between oxidants and antioxidants. A modification of the expression of crucial genes and epigenetic alterations is reported in hearts of PNOF animals. In vivo, a decreased ventricular contractile function is observed during adulthood in PNOF hearts. All these alterations ultimately lead to an increased sensitivity to cardiac pathologic challenges such as ischemia-reperfusion injury. Nevertheless, caloric restriction and physical exercise were shown to improve PNOF-induced cardiac dysfunction and metabolic abnormalities, drawing a path to the potential therapeutic correction of early nutritional programming. 相似文献
96.
97.
Quantitative characterization of degradation processes in situ by means of a bioreactor coupled flow chamber under physiological conditions using time‐lapse SRµCT
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98.
Reducing tobacco addiction through tobacco product regulation 总被引:4,自引:2,他引:4
Henningfield JE Benowitz NL Connolly GN Davis RM Gray N Myers ML Zeller M 《Tobacco control》2004,13(2):132-135
Tobacco product regulation has the potential to help reduce tobacco attributable disease by reducing the toxicity of these products and by reducing the prevalence of tobacco use and addiction. 相似文献
99.
Hermann Ehrlich Eike Brunner Paul Simon Vasily V. Bazhenov Joseph P. Botting Kontantin R. Tabachnick Armin Springer Kurt Kummer Denis V. Vyalikh Serguei L. Molodtsov Denis Kurek Martin Kammer René Born Alexander Kovalev Stanislav N. Gorb Petros G. Koutsoukos Adam Summers 《Advanced functional materials》2011,21(18):3473-3481
The hierarchically structured glass sponge Caulophacus species uses the first known example of a silica and calcite biocomposite to join the spicules of its skeleton together. In the stalk and body skeleton of this poorly known deep‐sea glass sponge siliceous spicules are modified by the addition of conical calcite seeds, which then form the basis for further silica secretion to form a spinose region. Spinose regions on adjacent spicules are then joined by siliceous crosslinks, leading to unusually strong cross‐spicule linkages. In addition to the biomaterials implications it is now clear, from this first record of a biomineral other than silica, that the hexactinellid sponges are capable of synthesizing calcite, the ancestral skeletal material. We propose that, while the low concentrations of calcium in deep sea waters drove the evolution of silica skeletons, the brittleness of silica has led to retention of the more resilient calcite in very low concentrations at the skeletal joints. 相似文献
100.
Free choice systems have home states 总被引:3,自引:1,他引:2
Summary This paper contains a proof that live and safe free choice Petri nets have home states. Home states are ones which can be reached from every successor state of the initial state. Liveness means that all actions remain executable, and safeness means that all capacities are finite. The result is interesting because it may help in the analysis of behavioural properties of complex systems. The existence of home states is a strong property which (as we will also show) fails to hold for a slightly generalised class of nets. 相似文献