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排序方式: 共有1906条查询结果,搜索用时 547 毫秒
41.
BK Park ES Cho JD Lee C Oh MS Lee SZ Kim SH Kim KW Cho 《Canadian Metallurgical Quarterly》1998,43(8):611-618
The effect of a naturally occurring plant phenolic constituent (the acylphloroglucinol derivative, jensenone, derived from Eucalyptus jensenii) on the food intake of two folivorous marsupials, the common ringtail (Pseudocheirus peregrinus) and the common brushtail possum (Trichosurus vulpecula) was studied. When fed diets containing varying concentrations of jensenone, both species regulated their intake of jensenone so as not to exceed a ceiling intake. This ceiling was about twice as high for common ringtails as for common brushtails from northern Australia. Southern populations of common ringtails showed greatly reduced capacities to tolerate jensenone. When common brushtails were injected (0.5 mg.kg-0.75 body mass) with ondansetron (a selective antagonist of serotonin 5HT3 receptors), they ate significantly more jensenone than animals injected with physiological saline. The same pattern was observed when common ringtails were fed diets containing both jensenone and ondansetron (0.0035 mg.g-1 wet mass of diet). Ondansetron injection had no effect on food intake when the food did not contain jensenone while the addition of higher doses of ondansetron to diets of common ringtails very slightly reduced food intakes of a non-jensenone diet. When common brushtails were given 50 mg of jensenone by gastric lavage, their average subsequent intake of dietary jensenone matched the difference between the daily threshold and the dose given, although the response of individuals was highly variable. Lavage with water alone had no effect on subsequent jensenone intake compared with the pre-dose period. We interpret these results as evidence that the antifeedant effects of jensenone and related compounds are partly mediated by serotonin action on 5HT3 receptors most likely via "nausea" to condition a food aversion. 相似文献
42.
Bai-Lin Qin Barbosa-Canovas G.V. Swanson B.G. Pedrow P.D. Olsen R.G. 《Industry Applications, IEEE Transactions on》1998,34(1):43-50
High-voltage pulsed electric fields (PEFs) can be used to inactivate microorganisms in liquids. Applying PEF technology to food pasteurization is a promising nonthermal method, which may radically change food preservation processes and provide consumers with microbiologically safe, minimally processed, fresh-like products. A continuous-flow system in a laboratory-size prototype was constructed for the nonthermal pasteurization of liquid foods with PEF technology. Major components in the prototype include a high-voltage repetitive pulse generator, a coaxial liquid food treatment chamber, a fiber-optic temperature sensing instrument and a data acquisition system. Microbial inactivation tests were conducted in the continuous PEF treatment system. Repetitive high-voltage pulses with an exponential decaying waveshape were applied to the liquid food which was pumped through the treatment chamber. Test microorganisms selected for inactivation were Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae. Over 6-order-of-magnitude reductions in the viability of selected microorganisms were achieved while the food temperature was maintained below 40°C 相似文献
43.
Targ R Steakley BC Hawley JG Ames LL Forney P Swanson D Stone R Otto RG Zarifis V Brockman P Calloway RS Klein SH Robinson PA 《Applied optics》1996,35(36):7117-7127
The use of airborne laser radar (lidar) to measure wind velocities and to detect turbulence in front of an aircraft in real time can significantly increase fuel efficiency, flight safety, and terminal area capacity. We describe the flight-test results for two coherent lidar airborne shear sensor (CLASS) systems and discuss their agreement with our theoretical simulations. The 10.6-μm CO(2) system (CLASS-10) is a flying brassboard; the 2.02-μm Tm:YAG solid-state system (CLASS-2) is configured in a rugged, light-weight, high-performance package. Both lidars have shown a wind measurement accuracy of better than 1 m/s. 相似文献
44.
ES Wiener RJ Touloukian BM Rodgers JL Grosfeld EI Smith MM Ziegler AG Coran 《Canadian Metallurgical Quarterly》1996,31(8):1166-1169
The members of the Section on Surgery of the American Academy of Pediatrics were surveyed to determine the practice of North American pediatric surgeons in infants with inguinal hernia (IH). Case-scenario multiple-choice-design questionnaires regarding hernias and hydroceles were sent to all members of the Surgical Section, and responses were received from 292 (50%). In healthy full-term infant boys with asymptomatic reducible IH, 82% of responders perform repair electively, no matter what the age or weight. In full-term girls with a reducible ovary, 59% perform surgery at the next available time; if the ovary is nonreducible but asymptomatic, 44% operate emergently or urgently and 42% at the next elective slot. In former preemies, the pattern of repair is as follows. (1) For those recently discharged after 2 months in the neonatal intensive care unit (NICU) with reducible IH, 65% perform the repair when convenient. (2) A general anesthetic is used in 70%; 15% use spinal anesthesia, and 11% use caudal block with sedation. (3) If the repair is done in the hospital outpatient (same-day) unit, 36% wait until 50 weeks postconception (PC) and 33% wait until 60 weeks PC. (4) if the baby's weight is at least 1,000 g. 71% perform the repair before discharge. The pain control choice after childhood IH repair is Tylenol for 30%, local infiltration biquivacaine for 30%, caudal block for 22%, regional block for 11%, and Tylenol/codeine combined for 7%. In 6-week-old full-term infants with communicating hydroceles without definite "hernia," two thirds treat as an IH with elective repair as soon as possible. With respect to contralateral exploration in infants with unilateral IH, 65% perform it in males if they are < or = 2 years of age and 84% use it in females of up to 4 years of age. This approach is not influenced by presenting side, presence of hydrocele, or history of prematurity. Laparoscopic evaluation of the contralateral IH is performed by only 6% of responders, 40% of whom use the open ipsilateral sac for laparoscope introduction. 相似文献
45.
ES van Waalwijk van Doorn AH Meier AW Ambergen RA Janknegt 《Canadian Metallurgical Quarterly》1996,23(3):345-371
This article elucidates the clinical applicability and state of the art of ambulatory urodynamics. Ambulatory urodynamics have evolved into practical investigations like EAC, HFM, and EAC combined with renal pelvimetry. EAC has been shown to be the method of preference if detrusor overactivity is involved. Conventional filling cystometry has proved to be an unreliable way to exclude detrusor instability. De novo instability after suspension surgery often indicates that an existing detrusor overactivity was not identified preoperatively. EAC including flowmetry has shown considerable variance in obstructive and contractility parameters in males with LUTS indicative for BPH. This raises doubt whether the clinical flow analysis is the suitable "gold standard" as advocated by the ICS. For a real break through of EAC, less complex automatic analysis is necessary. HFM is a newer method within the range of ambulatory urodynamic tests. It has not yet been completely evaluated. But, because the technique is analogous to the office flowmetry, noninvasive and very well accepted by the patients, it is expected to be widely used. This expectation is strengthened by the fact that HFM seems to show individual therapeutic efficacy of drugs, such as alpha-blockers. As a research tool to evaluate efficacy, it is far more powerful than conventional methods because of the reduction of within-patient standard deviation to about 10%. Finally, EAC combined with pelvimetry offers a promising method for the clinical evaluation of a combined dysfunction of upper and lower urinary tract. 相似文献
46.
E. Burton Swanson 《The Journal of Strategic Information Systems》2010,19(1):17-27
When firms innovate with information technology (IT), they frequently retain consultants, who presumably bring certain capabilities to the process. But what capabilities are these and why do they seem to be so needed? In this essay, I consider several different consultancy specializations – business strategy, technology assessment, business process improvement, systems integration, business support services – and how they facilitate an IT innovation process both within and across firms. For each specialization, I examine the consultancy’s capabilities and contributions both to the client (within an engagement) and to the broader support of the innovation (across and beyond engagements). The analysis suggests a number of conjectures as to the influence of consultancies on an IT innovation’s adoption, diffusion and eventual institutionalization. 相似文献
47.
A three-stage Runge-Kutta (RK) scheme with multigrid and an implicit preconditioner has been shown to be an effective solver for the fluid dynamic equations. Using the algebraic turbulence model of Baldwin and Lomax, this scheme has been used to solve the compressible Reynolds-averaged Navier–Stokes (RANS) equations for transonic and low-speed flows. In this paper we focus on the convergence of the RK/Implicit scheme when the effects of turbulence are represented by the one-equation model of Spalart and Allmaras. With the present scheme the RANS equations and the partial differential equation of the turbulence model are solved in a loosely coupled manner. This approach allows the convergence behavior of each system to be examined. Point symmetric Gauss-Seidel supplemented with local line relaxation is used to approximate the inverse of the implicit operator of the RANS solver. To solve the turbulence equation we consider three alternative methods: diagonally dominant alternating direction implicit (DDADI), symmetric line Gauss-Seidel (SLGS), and a two-stage RK scheme with implicit preconditioning. Computational results are presented for airfoil flows, and comparisons are made with experimental data. We demonstrate that the two-dimensional RANS equations and a transport-type equation for turbulence modeling can be efficiently solved with an indirectly coupled algorithm that uses RK/Implicit schemes. 相似文献
48.
H Villalobos ES Canales A Zárate J Soria C MacGregor 《Canadian Metallurgical Quarterly》1976,83(2):236-242
Serum levels of prolactin (PRL), FSH, LH and oestradiol-17 beta were determined by radioimmunoassay in 57 lactating women and in 20 women in whom lactation was inhibited by ergocryptine (CS-154). Women who breast fed their infants exhibited high PRL levels which abruptly declined within 48 h post-partum, and remained low for the duration of the study. Serum FSH was undetectable during the first week post-partum in lactating as well as in CB-154 treated women. Thereafter, lactating women showed increasing FSH levels which reached a maximum by the third week post-partum. These FSH values were higher in lactating women than in the CBS-154 treated group. In contrast, LH levels were higher in those women receiving CB-154. Serum oestradiol-17 beta remained in low levels throughout the study, and no difference was observed between the two groups of subjects. From these results it seems that: 1) inhibition of PRL secretion leads to a faster recovery of gonadotrophin secretion toward the "menstrual type", and 2) PRL suppression produces no effect on the ovarian oestrogen production. 相似文献
49.
Xiaoyi Wang Scott Kangas Divyachapan Padur Lei Liu James A. Swanson Arthur J. Helmicki Victor J. Hunt 《Canadian Metallurgical Quarterly》2005,10(4):460-467
Condition assessment is a term that is used to describe the process of characterizing the physical condition of constructed systems. This paper summarizes a condition assessment (CA) procedure based on a complete system of field-testing, finite element (FE) modeling, and load rating. Experimental techniques, including both modal testing and truckload testing, are used to collect measurements of the constructed systems. The basic mechanism and procedure of the FE modeling and calibration are presented. Different physical parameters of FE models are adjusted during the calibration process using both static and dynamic responses as criteria to achieve convergence between experimental measurements and analytical results using carefully developed objective functions. Finally, a bridge load rating is completed on the basis of the calibrated model. These developments are described and illustrated using a representative bridge as an example. 相似文献
50.
Scicli Andrea P.; Petrovich Gorica D.; Swanson Larry W.; Thompson Richard F. 《Canadian Metallurgical Quarterly》2004,118(1):5
Fos, the protein product of the immediate early gene c-fos, was used to map functional circuitry underlying contextual conditioned fear. Male rats were given footshocks in a distinctive context and later tested using freezing as the behavioral measure and compared with no-shock and no-retention-test control groups. An increased number of Fos-immunoreactive neurons was found in the lateral part of the central nucleus and in the anterior basolateral and lateral amygdalar nuclei in the brains of the conditioned-fear group compared with controls. Further, a greater number of Fos-immunoreactive neurons was observed in the right central and anterior basolateral nuclei compared with the number of labeled neurons in these structures on the left. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献