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21.
The Humanitarian Engineering initiative, sponsored by the William and Flora Hewlett Foundation, at the Colorado School of Mines, is creating a program that will support engineering students in understanding their responsibility for solving community development problems that exist throughout the world. As part of this effort, data has been collected on faculty and student attitudes using the ‘Community Service Attitudes Scale,” developed and validated by Shiarella, McCarthy, and Tucker. During the fall 2004, 78 students and 34 faculty members responded to this instrument. Statistically significant differences were found between the attitudes of students and faculty, males and females, and among different age groupings with respect to service activities. A general finding was that faculty displayed better attitudes toward community service than the students. 相似文献
22.
Classical conditioning of the nictitating membrane-eyeblink response in young (age 7 mo) and older (age 36 mo) New Zealand white rabbits in a delay paradigm with 400-msec CS–unconditioned stimulus/stimuli (UCS) interval was examined for initial acquisition and retention. Older animals required significantly more acquisition trials to reach learning criterion. Age differences in acquisition were temporary. Older rabbits responded at a level comparable to that of young rabbits such that total performance over the 630 trials of acquisition was not different. Rabbits in the explicitly unpaired control groups exhibited no age differences in unconditioned response (UCR) amplitude or latency measures. 12- and 18-mo retests demonstrated no significant age effects on retention. Patterns of retention differed between age groups. Older rabbits required fewer trials to obtain the learning criterion at each phase of testing. Younger rabbits maintained a stable performance throughout training. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
Ramon Codina 《Computer Methods in Applied Mechanics and Engineering》1993,110(3-4):237-262
The objective of this paper is to analyse an iterative procedure for the finite element solution of the Stokes and Navier-Stokes stationary problems. For the latter case, the usual condition on the viscosity and the data that ensures uniqueness is assumed. The method is based on the iterative imposition of the incompressibility condition via penalization. Theoretical and numerical results show that this constraint can be approximated iteratively within the same iterative loop used to deal with the nonlinear term of the equations. Two particular iterative schemes are analysed, namely those based on the Picard and Newton-Raphson algorithms. 相似文献
24.
Because of the rapid changes in saturation which take place in the immediate vicinity of a displacement front, it is not possible to estimate relative permeabilities over the entire saturation range of interest when using the external-drive method. It is demonstrated in this study that this limitation can be removed, if data from an unstabilized and/ or unstable displacement are used. Furthermore, it is shown that use of such data is permissible, provided: (a) saturation profiles and pressure gradients in both phases can be measured directly; (b) the external-drive theory is modified to account for the existence of capillary pressure gradients; and (c) the analysis is carried out from a Lagrangian rather than a Eulerian point of view.A comparison of relative permeabilities obtained by using the Lagrangian method with those obtained using the conventional (without capillary pressure term) and the modified (with the capillary pressure term) Eulerian methods was undertaken to demonstrate the effect of the neglect of the capillary pressure term on relative permeabilities. Also investigated in this study was the impact of instability on the relative permeability and capillary pressure curves for unstable displacements and the effect of instability on the saturation profiles, fractional flow curves and the residual oil saturation. In addition, the effect of instability on the residual oil saturation was studied. 相似文献
25.
Ramon Jansana Umberto Rivieccio 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(3):493-504
We introduce a new product bilattice construction that generalizes the well-known one for interlaced bilattices and others
that were developed more recently, allowing to obtain a bilattice with two residuated pairs as a certain kind of power of
an arbitrary residuated lattice. We prove that the class of bilattices thus obtained is a variety, give a finite axiomatization
for it and characterize the congruences of its members in terms of those of their lattice factors. Finally, we show how to
employ our product construction to define first-order definable classes of bilattices corresponding to any first-order definable
subclass of residuated lattices. 相似文献
26.
Evaluation of Floxuridine Oligonucleotide Conjugates Carrying Potential Enhancers of Cellular Uptake
Anna Avi Anna Clua Maria Jos Bleda Ramon Eritja Carme Fbrega 《International journal of molecular sciences》2021,22(11)
Conjugation of small molecules such as lipids or receptor ligands to anti-cancer drugs has been used to improve their pharmacological properties. In this work, we studied the biological effects of several small-molecule enhancers into a short oligonucleotide made of five floxuridine units. Specifically, we studied adding cholesterol, palmitic acid, polyethyleneglycol (PEG 1000), folic acid and triantennary N-acetylgalactosamine (GalNAc) as potential enhancers of cellular uptake. As expected, all these molecules increased the internalization efficiency with different degrees depending on the cell line. The conjugates showed antiproliferative activity due to their metabolic activation by nuclease degradation generating floxuridine monophosphate. The cytotoxicity and apoptosis assays showed an increase in the anti-cancer activity of the conjugates related to the floxuridine oligomer, but this effect did not correlate with the internalization results. Palmitic and folic acid conjugates provide the highest antiproliferative activity without having the highest internalization results. On the contrary, cholesterol oligomers that were the best-internalized oligomers had poor antiproliferative activity, even worse than the unmodified floxuridine oligomer. Especially relevant is the effect induced by palmitic and folic acid derivatives generating the most active drugs. These results are of special interest for delivering other therapeutic oligonucleotides. 相似文献
27.
Aintzane Rueda-Martínez Aiara Garitazelaia Ariadna Cilleros-Portet Sergi Marí Rebeca Arauzo Jokin de Miguel Brbara P. Gonzlez-García Nora Fernandez-Jimenez Jose Ramon Bilbao Iraia García-Santisteban 《International journal of molecular sciences》2021,22(11)
Endometriosis is a common gynecological disorder that has been associated with endometrial, breast and epithelial ovarian cancers in epidemiological studies. Since complex diseases are a result of multiple environmental and genetic factors, we hypothesized that the biological mechanism underlying their comorbidity might be explained, at least in part, by shared genetics. To assess their potential genetic relationship, we performed a two-sample mendelian randomization (2SMR) analysis on results from public genome-wide association studies (GWAS). This analysis confirmed previously reported genetic pleiotropy between endometriosis and endometrial cancer. We present robust evidence supporting a causal genetic association between endometriosis and ovarian cancer, particularly with the clear cell and endometrioid subtypes. Our study also identified genetic variants that could explain those associations, opening the door to further functional experiments. Overall, this work demonstrates the value of genomic analyses to support epidemiological data, and to identify targets of relevance in multiple disorders. 相似文献
28.
Fernando Corvillo Laura Gonzlez-Snchez Alberto Lpez-Lera Emilia Arjona Giovanni Ceccarini Ferruccio Santini David Araújo-Vilar Rebecca J Brown Joan Villarroya Francesc Villarroya Santiago Rodríguez de Crdoba Teresa Caballero Pilar Nozal Margarita Lpez-Trascasa 《International journal of molecular sciences》2021,22(12)
29.
Uptake of blood triglyceride by various tissues 总被引:3,自引:0,他引:3
Triglycerides are transported in the blood in chylomicrons and very low density lipoproteins. Electron microscopic studies
indicate that these particles, which range in diameter from 0.03–0.6 μ, cannot cross the capillary endothelium in most tissues.
There is now considerable evidence that the triglycerides are hydrolyzed to free fatty acids (FFA) during uptake and that
this process is catalyzed by lipoprotein lipase. The enzyme is found in nearly all tissues that utilize circulating triglyceride,
and the level of activity, in individual tissues, varies with nutritional and physiological states that affect triglyceride
uptake, such as fasting, diabetes and pregnancy. Studies in perfused adipose tissue with doubly labeled chylomicrons showed
that hydrolysis occurs outside of the blood stream. Two-thirds of the fatty acids are incorporated into tissue triglyceride
and the rest are release as FFA, with glycerol, to the blood. Infusion of heparin causes immediate release of lipoprotein
lipase activity to the blood and decreases the amount of chylomicron-triglyceride hydrolyzed by the tissue. Electron microscopic
cytochemical studies showed that hydrolysis of blood glycerides by lipoprotein lipase in adipose tissue occurs within the
capillary endothelial cells and in the subendothelial space near the pericytes, but not in the capillary lumen or near the
fat cells. The results indicate that the fatty acids of chylomicrons cross the capillary endothelium as glycerides and FFA,
within a membrane-bounded system, and cross the extravascular space to the fat cells as FFA.
Presented at the AOCS Meeting, Atlantic City, October 1971. 相似文献
30.
Xiaohong Gu Tinh Nguyen Mounira Oudina David Martin Bouchra Kidah Joan Jasmin Aziz Rezig Lipiin Sung Eric Byrd Jonathan W. Martin Derek L. Ho Y. C. Jean 《Journal of Coatings Technology and Research》2005,2(7):547-556
Atomic force microscopy (AFM) has been used to study the morphology and microstructure of an amine-cured epoxy before and
after outdoor exposure. Measurements were made from samples prepared in an essentially CO2-free, H2O-free glove box and from samples prepared in ambient conditions. For those prepared in a CO2-free glove box, AFM imaging was conducted on (1) an unexposed air/coating surface, (2) an unexposed coating bulk, (3) an
unexposed coating/substrate interface, and (4) a field exposed air/coating surface. For samples prepared in ambient conditions,
only the unexposed air/coating surface was investigated. The same regions of the exposed samples were scanned periodically
by the AFM to monitor changes in the surface morphology of the coating as UV exposure progressed. Small angle neutron scattering
and Fourier transform infrared spectroscopy (FTIR) studies were performed to verify the microstructure and to follow chemical
changes during outdoor exposure, respectively. The results have shown that amine blushing, which occurs only under ambient
conditions, had a significant effect on the surface morphology and microstructure of the epoxy. The surface morphology of
the samples prepared under CO2-free, dry conditions was generally smooth and homogeneous. However, the interface and the bulk samples clearly revealed a
two-phase structure consisting of bright nodular domains and dark interstitial regions, indicating an inhomogeneous microstructure.
Such heterogeneous structure of the bulk was in good agreement with results obtained by small angle neutron scattering of
unexposed samples and by AFM phase imaging of the degraded sample surface. The relationship between submicrometer physical
changes and molecular chemical degradation is discussed.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago,
IL. 相似文献