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21.
Calculations utilizing the exact solutions for the temperature distributions of the solid in and the fluid flowing through a packed bed with arbitrary initial bed temperature and arbitrary inlet fluid temperature have been carried out. The computational method allows a reversal of the direction of the flow at arbitrary times. The influence of the nondimensional frequency of a periodic flow reversal on the bed and fluid temperatures at the steady periodic state are presented. 相似文献
22.
Rose Richard J.; Koskenvuo Markku; Kaprio Jaakko; Sarna Seppo; Langinvainio Heimo 《Canadian Metallurgical Quarterly》1988,54(1):161
Similarities for Extraversion (E) and Neuroticism (N) scale scores from the Eysenck Personality Inventory were evaluated in 7,144 adult twin pairs, drawn from the population-based Finnish Twin Cohort, as a function of the co-twins' genetic resemblance, gender, age, and the frequency of their social interaction with each other. To separate effects of shared genes from those of shared experience, we performed hierarchical multiple regressions of double-entry data matrices. Results establish the predictive significance of both genetic and experiential influences: Genetic effects remained significant when tested after the effects of social contact were first removed; conversely, for N scores, the effects of social contact remained significant when assessed after genetic influences were first removed. These findings establish genetic variance in major dimensions of adult personality but assign a significant role to common experience as well. The first finding constructively replicates reports by others; the second challenges the widespread assumption that shared experiences have a negligible impact on sibling similarity in adult personality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
Optical communications networks require integrated photonic components with negligible polarization dependence, which typically means that the waveguides must feature very low birefringence. Recent studies have shown that waveguides with low birefringence can be obtained, e.g., by use of silica-on-silicon waveguides or buried ion-exchanged glass waveguides. However, many integrated photonic circuits consist of waveguides with varying widths. Therefore low birefringence is consequently required for waveguides having different widths. This is a difficult task for most waveguide fabrication technologies. We present experimental results on waveguide birefringence for buried silver-sodium ion-exchanged glass waveguides. We show that the waveguide birefringence of the order of 10(-6) for waveguide mask opening widths ranging from 2 to 10 microm can be obtained by postprocessing the sample through annealing at an elevated temperature. The measured values are in agreement with the values calculated with our modeling software for ion-exchanged glass waveguides. This unique feature of ion-exchanged waveguides may be of significant importance in a wide variety of integrated photonic circuits requiring polarization-independent operation. 相似文献
24.
Four surveys of breath alcohol were conducted on two motorboat passages at the archipelago of the Gulf of Finland on Friday and Saturday afternoons in summer 1978. All passing motorboats were controlled by the police and the drivers were breathanalyzed with AlcolmeterR. The breath test was positive for 126 (29.7%) of 424 examined drivers. Mainly these drivers had ingested small amounts of alcohol, and in only five cases (1.2%) did the blood alcohol result exceed the statutory blood alcohol limit, which is 0.15% for motored water traffic in Finland. The present study suggest a remarkable difference in people's attitudes toward driving a motor vehicle on land or at sea in their free time after ingestion of alcohol. 相似文献
25.
Wavelet-based reconstruction for limited-angle X-ray tomography 总被引:1,自引:0,他引:1
Rantala M Vänskä S Järvenpää S Kalke M Lassas M Moberg J Siltanen S 《IEEE transactions on medical imaging》2006,25(2):210-217
The aim of X-ray tomography is to reconstruct an unknown physical body from a collection of projection images. When the projection images are only available from a limited angle of view, the reconstruction problem is a severely ill-posed inverse problem. Statistical inversion allows stable solution of the limited-angle tomography problem by complementing the measurement data by a priori information. In this work, the unknown attenuation distribution inside the body is represented as a wavelet expansion, and a Besov space prior distribution together with positivity constraint is used. The wavelet expansion is thresholded before reconstruction to reduce the dimension of the computational problem. Feasibility of the method is demonstrated by numerical examples using in vitro data from mammography and dental radiology. 相似文献
26.
Adhesion properties and competitive pathogen exclusion ability of bifidobacteria with acquired acid resistance 总被引:1,自引:0,他引:1
The adhesion properties of Bifidobacterium longum and Bifidobacterium catenulatum strains with an acquired resistance to acid and their ability to competitively exclude Salmonella enterica serovar Typhimurium, Escherichia coli, Listeria monocytogenes, Enterobacter sakazakii, and Clostridium difficile from adhering to human intestinal mucus were evaluated and compared with the results when the same experiments were run with the original acid-sensitive strains. In half of the four studied cases, the acid-resistant derivative showed a greater ability to adhere to human intestinal mucus than the original strain. The ability of bifidobacteria to inhibit pathogen adhesion to mucus was not generally improved by the acquisition of acid resistance. In contrast, three of the four acid-resistant strains showed a greater ability to displace preadhered pathogens than the original strains, especially preadhered Salmonella Typhimurium and C. difficile. Overall, the induction of acid resistance in bifidobacteria could be a strategy when selecting strains with enhanced stability and improved surface properties that favor their potential functionality as probiotics against specific pathogens. 相似文献
27.
Magdalena Markowicz-Piasecka Johanna Huttunen Ahmed Montaser Santosh Kumar Adla Seppo Auriola Marko Lehtonen Kristiina M. Huttunen 《International journal of molecular sciences》2021,22(14)
Efflux transporters, namely ATP-binding cassette (ABC), are one of the primary reasons for cancer chemoresistance and the clinical failure of chemotherapy. Ganciclovir (GCV) is an antiviral agent used in herpes simplex virus thymidine kinase (HSV-TK) gene therapy. In this therapy, HSV-TK gene is delivered together with GCV into cancer cells to activate the phosphorylation process of GCV to active GCV-triphosphate, a DNA polymerase inhibitor. However, GCV interacts with efflux transporters that are responsible for the resistance of HSV-TK/GCV therapy. In the present study, it was explored whether GCV and its more lipophilic derivative (1) could inhibit effluxing of another chemotherapeutic, methotrexate (MTX), out of the human breast cancer cells. Firstly, it was found that the combination of GCV and MTX was more hemocompatible than the corresponding combination with compound 1. Secondly, both GCV and compound 1 enhanced the cellular accumulation of MTX in MCF-7 cells, the MTX exposure being 13–21 times greater compared to the MTX uptake alone. Subsequently, this also reduced the number of viable cells (41–56%) and increased the number of late apoptotic cells (46–55%). Moreover, both GCV and compound 1 were found to interact with breast cancer resistant protein (BCRP) more effectively than multidrug-resistant proteins (MRPs) in these cells. Since the expression of BCRP was higher in MCF-7 cells than in MDA-MB-231 cells, and the cellular uptake of GCV and compound 1 was smaller but increased in the presence of BCRP-selective inhibitor (Fumitremorgin C) in MCF-7 cells, we concluded that the improved apoptotic effects of higher MTX exposure were raised mainly from the inhibition of BCRP-mediated efflux of MTX. However, the effects of GCV and its derivatives on MTX metabolism and the quantitative expression of MTX metabolizing enzymes in various cancer cells need to be studied more thoroughly in the future. 相似文献
28.
Maria Carmen Collado Jussi Meriluoto Seppo Salminen 《European Food Research and Technology》2008,226(5):1065-1073
Autoaggregation has been correlated with adhesion, which is known to be a prerequisite for colonization and infection of the
gastrointestinal tract by many pathogens. The coaggregation properties of probiotic strains with pathogens as well as their
ability to displace pathogens are of importance for therapeutic manipulation of the aberrant intestinal microbiota. Consequently,
the ability to aggregate and coaggregate are desirable properties for probiotics in health-promoting foods. Aggregation assays
and bacterial adhesion to hydrocarbons (BATH test) demonstrated significant differences in cell surface properties among the
tested commercial probiotic strains. Hydrophobicity increased when the cells were heat-inactivated. All probiotic strains
tested showed aggregation abilities with the pathogen strains tested, but the results were strain-specific and dependent on
time and incubation conditions. Our results indicate that the ability to autoaggregate, together with cell-surface hydrophobicity
and coaggregation abilities with pathogen strains can be used for preliminary screening in order to identify potentially probiotic
bacteria suitable for human or animal use. 相似文献
29.
30.
Mari J. Jaakamo Tytti J. Luukkonen Piia K. Kairenius Ali R. Bayat Seppo A. Ahvenjärvi Tuomo M. Tupasela Johanna H. Vilkki Kevin J. Shingfield Heidi M. Leskinen 《Journal of dairy science》2019,102(10):8825-8838
We examined the effects of 2 grass silage-based diets differing in forage:concentrate (FC) ratio and those of a red clover silage-based diet on intake, milk production, ruminal fatty acid (FA) biohydrogenation, milk FA composition, and milk fat globule (MFG) size distribution. Ten multiparous Nordic Red cows received the following treatments: grass silage-based diets containing high (70:30, HG) or low (30:70, LG) FC ratio or a red clover silage-based diet with an FC ratio of 50:50 (RC) on a dry matter basis. Determinations of MFG were performed from fresh milk samples without addition of EDTA so the results of fat globules >1 µm in diameter are emphasized instead of the entire globule population. Lower FC ratio in grass silage-based diets increased milk production with no effect on daily fat yield, leading to 13% lower milk fat concentration. The effect of FC ratio on MFG size was moderate. It did not affect the volume-weighted diameter in grass silage-based diets, although LG lowered the volume-surface diameter of MFG in the size class >1 µm compared with HG. Compared with HG, feeding LG moderately decreased the biohydrogenation of 18:2n-6, leading to a higher level of polyunsaturated fatty acids in milk fat. Feeding RC lowered milk fat concentration and daily milk fat yield compared with grass silage-based diets. The volume-weighted diameter of MFG in the size class >1 µm was smaller in RC milk compared with grass silage-based diets. Feeding RC increased the flow of 18:3n-3 at the omasum by 2.4-fold and decreased the apparent ruminal 18:3n-3 biohydrogenation compared with grass silage-based diets despite similar intake of 18:3n-3. It also resulted in the lowest amount of saturated FA and the highest amounts of cis-9 18:1, 18:3n-3, and polyunsaturated FA in milk. In conclusion, LG decreased milk fat content and induced minor changes in MFG size distribution compared with HG, whereas RC lowered milk fat production, altered milk FA composition to nutritionally more beneficial direction, and led to smaller MFG compared with grass silage-based diets. 相似文献