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41.
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Abstract The height equivalent to a theoretical stage (HETS) is estimated using one correlation to describe behavior for reciprocating speeds below the optimum point and a second expression to estimate HETS values for reciprocating speeds above it. These two equations are then combined to yield a generalized expression that is applicable in both regions and which can be used to predict the minimum HETS and the optimum reciprocating speed. The observed dependence on the operating parameters and the physical properties of the liquid/liquid system generally agree with those observed in HETS correlations for pulse columns. 相似文献
43.
Monoterpenes such as limonene and perillyl alcohol (PA) are currently under investigation for their chemotherapeutic properties
which have been tied to their ability to affect protein isoprenylation. Because PA affects the synthesis of isoprenoids’ such
as ubiquinone’ and cholesterol is the end product of the synthetic pathway from which this isoprenoid pathway branches’ we
investigated the effects of this compound upon cholesterol metabolism in the colonic adenocarcinoma cell line SW480. PA (1
mM) inhibited incorporation of 14C-mevalonate into 21–26 kDa proteins by 25% in SW480 cells. Cholesterol (CH) biosynthesis was assessed by measuring the incorporation
of 14C-acetate and 14C-mevalonate into 27-carbon-sterols. Cells treated with PA (1 mM) exhibited a fourfold increase in the incorporation of 14C-acetate but not 14C-mevalonate into cholesterol. Mevinolin (lovastatin)’ an inhibitor of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase’
at 2 μM concentration’ inhibited CH synthesis from 14C-acetate by 80%. Surprisingly’ concurrent addition of mevinolin and PA did not significantly alter the stimulatory effects
of PA. As observed differences in 14C-acetate and 14C-mevalonate precursor labeling could indicate PA affects early pathway events’ the effects of this monoterpene on HMG-CoA
reductase activity were evaluated. Unexpectedly’ 1 mM PA did not stimulate activity of this enzyme. Consistent with its action
as a reversibly bound inhibitor’ in washed microsomes’ 2 μM mevinolin pretreatment increased reductase protein expression
causing a 12.7 (±2.4)-fold compensatory HMG-CoA reductase activity increase; concurrent treatment with 1 mM PA attenuated
this to a 5.3 (±0.03)-fold increase. Gas chromatographic analysis confirmed CH was the major lipid present in the measured
thin-layer chromatography spot. Since 14C-acetate incorporation into free fatty acid and phospholipid pools was not significantly affected by PA treatment’ nonspecific
changes in whole acetate pool sizes were not indicated. Because increases in endogenous CH synthesis should result in compensatory
changes in exogenous sterol utilization’ the effects of PA upon low density lipoprotein (LDL) receptor activity were evaluated.
Consistent with the observed increases in CH synthesis’ 1 mM PA decreased 125I-LDL internalization to 50% of the fetal bovine serum control; concurrent addition of 2 μM mevinolin attenuated this effect
to a reduction of 80% of the control value. Data suggest that in certain colonic tumor cells PA strongly affects cholesterol
metabolism via a mechanism of action that is insensitive to the HMG-CoA reductase inhibitor mevinolin. 相似文献
44.
OBJECTIVES: As the incidence of prostate cancer in the United States exceeds 330,000 in 1997, increasingly more men are faced with treatment choices for which there is no clear approach. At every stage of disease, these treatment choices may involve clinically equivalent modalities that differ in side effects and impact upon quality of life (QOL). Comprehensive, yet efficient, questionnaires are needed to measure QOL in patients with prostate cancer. METHODS: Developed as a disease-specific adjunct to the Functional Assessment of Cancer Therapy (FACT) measurement system, a 12-item prostate cancer subscale (PCS) was developed and tested in three independent samples: a subscale development sample (n = 43), validity sample 1 (n = 34), and validity sample 2 (n = 96). The 12 items ask about symptoms and problems specific to prostate cancer. These questions are added to the general (FACT-G) instrument, thereby comprising a 47-item questionnaire. RESULTS: Internal consistency of the PCS ranged from 0.65 to 0.69, with coefficients for FACT-G subscales and aggregated scores ranging from 0.61 to 0.90. Concurrent validity was confirmed by the ability to discriminate patients by disease stage, performance status, and baseline prostate-specific antigen (PSA) level. Sensitivity to change in performance status and PSA score over a 2-month period suggested that some subscales of the FACT-Prostate (P) (including the PCS) are sensitive to meaningful clinical change. CONCLUSIONS: Our findings support use of the FACT-P as a meaningful component of QOL evaluation in men undergoing therapy for prostate cancer. 相似文献
45.
This paper discusses the issues of providing an empirically validated, manual-based-treatment when viewed from the perspective of a practicing clinical psychologist. The trend for empirically proven treatment is reviewed briefly, and initial data are provided illustrating a manual-based-treatment for post-traumatic stress disorder (PTSD) following a motor vehicle accident. The relatively brief (9-12 session) psychological treatment was effective in reducing PTSD symptoms as measured on the Clinician Administered PTSD Scale, for all 10 subjects. The results are discussed form the practicing clinician's perspective: generalization to a clinical population, ethical concerns of limited treatment goals, individually tailored vs standardized treatments in clinical practice, concerns for co-morbid conditions, and how this type of study might impact on practice in an era of managed health care. Issues of incorporating manual based treatments into clinical practice are discussed, with consideration of gains, the limits and the constraints this would bring to the practice of psychology. 相似文献
46.
The vigilance reaction is characterized by a large bradycardia, a pressor response, and inspiratory apnea in anesthetized rabbits and the inhibition of movement in conscious rabbits. This affective response pattern can be elicited by electrical stimulation of the dorsolateral hypothalamus (the hypothalamic vigilance area) or the ventrolateral periaqueductal gray (the periaqueductal gray vigilance area). The present study sought to advance our understanding of the functional relationship between the hypothalamic vigilance area (HVA) and the periaqueductal gray vigilance area (PVA) by measuring the effects of transverse transections of the caudal portion of the ventrolateral PAG (vlPAG) upon the cardiovascular responses elicited from the dorsolateral hypothalamus and the rostral vlPAG. Selective transverse transections of the caudal vlPAG significantly reduced the magnitudes of the bradycardia and pressor response elicited by stimulation of the PVA rostral to the transection site, but had minimal impact on the cardiovascular responses evoked by stimulation of the HVA. These findings suggest that the cardiovascular responses elicited by stimulation of the vlPAG are mediated by a neural pathway that is parallel, at least in part, to the one that subserves the response elicited from the HVA. The results also provide support for the view that the PAG is not an essential structure in the mediation of the autonomic components of affective behaviors involving behavioral inhibition. 相似文献
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The use of complex materials, such as composites, for fabrication of structural components exacts a price of increased complexity in design and analysis of these structures. In order to economically and efficiently facilitate complex structural design and analysis, computer-aided design techniques are being employed throughout the industrial community. This paper illustrates a system of computer-aided design techniques and software (CADOT) for the design and analysis of engineering structures and solids that are constructed of sheet molding, injection molding, and/or laminated composite technologies. 相似文献
50.
Luccas Fernando Bittencourt De Souza Haywood Dail Laughinghouse IV Tamara Pastori Marília Tedesco Andrielle Wouters Kuhn Thais Scotti Do Canto‐Dorow 《The International journal of environmental studies》2013,70(6):871-877
Artemisia verlotorum, popularly ‘infalivina’, is a medicinal herb used for respiratory, circulatory and digestive treatments. Antiproliferative and genotoxic effects of A. verlotorum aqueous extracts in three different concentrations (6, 32 and 48 g/L) were evaluated on the Allium cepa cell cycle. Results clearly showed a significant difference using the χ2 test (p = 0.05) among treatments with a decrease in the mitotic index as the concentration of the extract increased. Extracts of A. verlotorum proved to be genotoxic and showed antiproliferative potential on the A. cepa cell cycle. This study suggests the use of infusions of A. verloturum for medicinal purposes only after selecting suitable concentrations. 相似文献