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排序方式: 共有1006条查询结果,搜索用时 31 毫秒
101.
A PCR approach (transposon PCR) with primers based on repetitive transposon-like sequences, which--depending on the isolate--were found at a minimum frequency of 19 on the C. burnetii genome, was established for the highly sensitive and specific detection of C. burnetii. This study describes the analytical detection of C. burnetii in milk, which requires a special preparation method prior to PCR. Because of the low level of C. burnetii particles in milk samples, template DNA was concentrated by a factor of 200, using cetyltrimethylammonium bromide as the precipitation reagent. Using this particular preparation method, even a single C. burnetii particle could be detected in 1 ml milk. 相似文献
102.
MM Wittenbrink C Reuter K Baumeister H Schütze H Krauss 《Canadian Metallurgical Quarterly》1998,288(1):45-57
The degree of chemical shift similarity for homologous proteins has been determined from a chemical shift database of over 50 proteins representing a variety of families and folds, and spanning a wide range of sequence homologies. After sequence alignment, the similarity of the secondary chemical shifts of C alpha protons was examined as a function of amino acid sequence identity for 37 pairs of structurally homologous proteins. A correlation between sequence identity and secondary chemical shift rmsd was observed. Important insights are provided by examining the sequence identity of homologous proteins versus percentage of secondary chemical shifts that fall within 0.1 and 0.3 ppm thresholds. These results begin to establish practical guidelines for the extent of chemical shift similarity to expect among structurally homologous proteins. 相似文献
103.
Ayre M. Karle T.J. Lijun Wu Davies T. Krauss T.F. 《Selected Areas in Communications, IEEE Journal on》2005,23(7):1390-1395
We present the experimental measurement of a photonic crystal (PhC) device comprising an injector, Y-splitter, and 60/spl deg/ bend. The complete device consists of a 9-/spl mu/m-long injector tapering down from 5 /spl mu/m into a triangular-lattice-of-holes single-line defect waveguide with period a=430 nm and 36.2% air filling factor (corresponding to a radius over period (r/a) ratio of 0.30), an optimized Y-junction, 60/spl deg/ bend and output injectors, with a total device footprint of 30 /spl mu/m. This is etched into a GaAs/AlGaAs heterostructure using chlorine/argon chemically assisted ion beam etching (CAIBE). An erbium-doped fiber amplifier (EDFA)-based source and Fabry-Perot technique are used to characterize the device. The device displays a bandwidth of approximately 110 nm in the 1.55 /spl mu/m window, and a transmission of 70% relative to the same length of 5-/spl mu/m-wide waveguide. This is compared with three-dimensional finite-difference time-domain (3-D FDTD) results, which have a bandwidth and transmission of 120 nm and 75%, respectively. The highlight of this paper is the close agreement of the numerically optimized complete microcircuit with its experimental equivalent, and the significant improvement in bandwidth over previous work on Y-junctions. 相似文献
104.
Explored the relationship between identity and changes in physical functioning over the adult years. 242 adults (aged 40–95 yrs) rated themselves in 20 areas of normative functioning and identity processes. Measures included the Physical and Cognitive Change Scale, the Identity and Experiences Scale—Specific Aging, and the Rosenberg Self-Esteem Questionnaire. The findings indicate that adults as young as 40 are sensitive to age-related changes. Those 65 and older exhibited greater sensitivity to changes in competence. Identity assimilation was used most by adults under 65, particularly in the area of cognitive functioning. For individuals in both age groups, identity assimilation was positively related to self-esteem. The findings suggest that individuals may make behavioral adjustments without ruminating or becoming preoccupied, a strategy that may promote healthy adaptation to the aging process. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
AH Krauss DF Woodward J Chen LL Gibson RK Lai CE Protzman T Shan LS Williams TS Gac RM Burk 《Canadian Metallurgical Quarterly》1995,11(3):203-212
The possible subdivision of thromboxane A2-sensitive (TP) receptors is currently a controversial subject. We report herein on a novel thromboxane A2 mimetic, AGN 191976, which has almost identical pharmacological activity to the well-characterized prostaglandin H2/thromboxane A2 (PGH2/TxA2) mimetic U-46619, but its effects on intraocular pressure are quite distinct from U-46619. Prostanoid receptor activity was determined in vitro using different smooth muscle assays and platelets. Intraocular pressure was measured tonometrically in ocular normotensive Beagle dogs and Cynomolgus monkeys. Conjunctival microvascular permeability was determined in guinea pigs. Despite closely resembling U-46619 as a potent and selective TP receptor agonist, AGN 191976 was a potent ocular hypotensive in dogs and monkeys whereas U-46619 did not lower IOP in either species. The ocular hypotensive effect of AGN 191976 in dogs was attenuated by pretreatment with the TP receptor antagonist SQ 29548. Thus, the ocular hypotensive effects of AGN 191976 are consistent with TP receptor stimulation. Both TxA2-mimetics caused plasma leakage in the guinea pig conjunctiva. The disparate activities of U-46619 and AGN 191976 in our studies suggest the existence of heterogeneous populations of TP-receptors in the eye. 相似文献
106.
Frederick H. Mies Carl J. Williams Paul S. Julienne Morris Krauss 《Journal of research of the National Institute of Standards and Technology》1996,101(4):521-535
We present quantum scattering calculations for the collisional relaxation rate coefficient of spin-polarized 87Rb(f = 2,m = 2) atoms, which determines the loss rate of cold Rb atoms from a magnetic trap. Unlike the lighter alkali atoms, spin-polarized 87Rb atoms can undergo dipolar relaxation due to both the normal spin-spin dipole interaction and a second-order spin-orbit interaction with distant electronic states of the dimer. We present ab initio calculations for the second-order spin-orbit terms for both Rb2 and Cs2. The corrections lead to a reduction in the relaxation rate for 87Rb. Our primary concern is to analyze the sensitivity of the 87Rb trap loss to the uncertainties in the ground state molecular potentials. Since the scattering length for the a3Σ+u state is already known, the major uncertainties are associated with the X1Σ+g potential. After testing the effect of systematically modifying the short-range form of the molecular potentials over a reasonable range, and introducing our best estimate of the second-order spin-orbit interaction, we estimate that in the low temperature limit the rate coefficient for loss of Rb atoms from the f = 2,m = 2 state is between 0.4 × 10−15 cm3/s and 2.4 × 10−15 cm3/s (where this number counts two atoms lost per collision). In a pure condensate the rate coefficient would be reduced by 1/2. 相似文献
107.
OBJECTIVE: To determine the incidence and clinical and pathological features of chromophobe cell carcinoma (CCC) among renal cell carcinomas (RCCs). MATERIALS AND METHODS: The records and nephrectomy samples from 166 patients who were operated on and followed up thereafter with a diagnosis of RCC were re-evaluated. New sections were cut and specific staining performed when deemed necessary. RESULTS: Of 166 patients with RCC, six were diagnosed as having CCC and, unusually, one patient had a mixed RCC with areas of CCC. Neither the symptoms nor radiological features of these seven patients differed from those of the patients with RCC; the serum ferritin levels of these seven patients were also within the normal range. These patients appeared to have a favourable clinical course. CONCLUSION: Chromophobe cell carcinoma is a distinct entity and must be distinguished particularly from oncocytoma and other variants of RCC. Although it seems to have a low malignant potential, metastatic CCC may have a worse prognosis. 相似文献
108.
OBJECTIVES: Previous studies of surgical treatment for cervical dystonia have reported highly variable rates of postoperative symptomatic benefit and morbidity. Little is known about functional improvement and long term results. This study evaluates the symptomatic and functional outcome of surgical treatment of cervical dystonia in a consecutive series of 46 patients. METHODS: The most affected muscles were selected for denervation after clinical examination and confirmation by four channel EMG studies. Surgical treatment, aiming at selective elimination of pathological activity while preserving normal motor function and avoiding side effects, was achieved by using a broad scope of techniques including intradural denervation, extradural denervation, and myotomy. Rather than carrying out standard operations, the treatment was tailored to the needs of the patient according to the individual pattern of dystonic activity. Long term benefit was assessed with a global outcome score, and a modified Toronto western spasmodic torticollis rating scale (TWSTRS) in those 34 patients who were available for a recent follow up evaluation. RESULTS: The 46 patients underwent a total of 70 procedures with intradural approaches in 33 instances, extradural approaches in 21, and muscle sections (singly or combined) in 22 instances. Transient mild postoperative side effects occurred in 10% of the procedures. The mean duration of long term follow up was 6.5 years. The global outcome was rated as excellent in nine patients (21%), as marked in 12 (27%), as moderate in nine (21%), as mild in nine (21%), and as no improvement in five (11%). A persistent side effect consisting of mild difficulty with balance was noted in one case. There were highly significant changes of the preoperative and postoperative mean values for almost all TWSTRS subscores for severity of cervical dystonia, functional disability, and pain. Patients with excellent outcome underwent a higher number of surgical procedures on average than those patients who achieved no benefit. CONCLUSIONS: Surgical treatment tailored to the specific pattern of dystonic activity in the individual patient is a valuable alternative in the long term management of cervical dystonia. 相似文献
109.
The rare-earth diiodides, MI2, may be synthesized from the corresponding triiodides, MI3, by reduction with their metals at elevated temperatures or, alternatively, through so-called metallothermic reduction reactions with alkaline or alkaline-earth metals. In these cases, ternary iodides may be obtained that may be derived from the binary diiodides by either formal addition or substitution. Prominent formula types that are thus obtained are AIMI3, or the mixed-valent AI5MII2MIIII12 and AIIMI4 with AI and AII representing alkaline or alkaline-earth elements (and their analogues), respectively. Further iodides that are relevant in these systems are, for example, Pr2I5, Ba6Pr3I19 and interstitially stabilized phases such as {Er14(N2)(C2)2}I24, La9O4I16 and Ba{Ce4N2}I8. 相似文献
110.
L. Hobbs I. Eddie G. Erwin A. C. Bryce R. M. De La Rue J. S. Roberts T. F. Krauss D. W. Mccomb M. Mackenzie 《Journal of Electronic Materials》2005,34(3):232-239
Annealing or processing of AlAs that has been subjected to a wet thermal oxidation process can result in severe delamination
of material at the oxidation front. This paper reports a procedure for preventing this delamination and presents a possible
cause for the delamination. 相似文献