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1.
Vladislav Nodelman Harihara Baskaran James S. Ultman 《Annals of biomedical engineering》1998,26(6):1044-1054
An intravascular gas exchange device for the treatment of respiratory failure consisted of a multitude of blind-ended hollow fibers glued in a pine-needle arrangement to a central gas supply catheter. It has previously been shown that gas desorption rates can be significantly enhanced by cycling gas pressure between a hypobaric level of 130 and an ambient level of 775 Torr. In this study, influences of the cycling frequency (f) and the cycle fraction during which hypobaric pressure is applied () were investigated. Rates of O2 desorption from O2-saturated water and CO2 desorption from CO2-saturated water into a manifold containing 198 fibers, 380 m in diameter, were measured over a range of f from 0.2 to 1.0 Hz, from 0.1 to 0.8, and fiber lengths from 4 to 16 cm. Relative to operation at ambient pressure, pressure cycling increased O2 transfer 3–4 times and CO2 transfer 4–6 times when the water flowed over the fiber manifold at 2.3 l/min. Transfer rates were relatively insensitive to f and with 80–90% of maximum enhancement obtained when was as low as 0.2. Transfer rates increased continuously with fiber length, implying that pressure cycling reduced the intra-fiber resistance to gas diffusion. A mathematical diffusion model which utilized only two adjustable parameters, a mass transfer coefficient for O2 and for CO2, simulated the trends exhibited by desorption data. © 1998 Biomedical Engineering Society.
PAC98: 8745Hw, 8790+y 相似文献
2.
Isaguliants MG Petrakova NV Mokhonov VV Pokrovskaya K Suzdaltzeva YG Krivonos AV Zaberezhny AD Garaev MM Smirnov VD Nordenfelt E 《Immunology letters》2003,88(1):1-13
Nonstructural protein 3 (NS3) of human hepatitis C virus (HCV) is a conserved multi-functional protein essential for replication and translation of viral RNA and polyprotein processing. Early T-cell response against NS3 is capable of restricting viremia. We aimed at characterizing the immunogenicity in gene immunization of the conserved regions of NS3 critical for protein folding and activity. C57BL/6 mice were injected with NS3 gene of Russian HCV 1b isolate 274933RU. Immunization did not exert any overt histological changes and had no long-term effects on the immune status of NS3 gene-recipients. The immune response in NS3 gene-recipients was screened by antibody ELISA, T-cell proliferation test and immune assays for specific cytokine production. T-lymphocytes of NS3 gene-recipients proliferated in response to peptides representing conserved regions of protease and ATPase/helicase. Stimulated T-lymphocytes produced IL-2, and in response to protease-derived peptides, also IFN-gamma. Potent and long-lasting antibody response was raised against conserved NS3 regions including "Greek-key" motif of protease, motifs II, V and polynucleotide-binding domains of ATPase/helicase. Thus, gene immunization effectively targeted conserved regions critical for NS3 protease and helicase function. In type and specificity, immune response of NS3 gene-immunized mice mimicked immunity achieved in the acute self-limiting HCV infection of human and primates and in virus-exposed healthy individuals, indicating promiscuity of NS3 as immunogen. 相似文献
3.
Ivana Vančurová Miroslav Flieger Jindřich Volc Milan J. Beneš Jana Novotná Jiří Neužil Vladislav Běhal 《Journal of basic microbiology》1987,27(9):529-533
Anhydrotetracycline oxygenase was purified both by affinity chromatography and by hydrophobic interaction chromatography. Molecular weight of anhydrotetracycline oxygenase was determined to be 115,000 by Sephadex G-200 gel filtration. Using preparative isoelectric focusing the isoelectric point of the enzyme was estimated to be 5.3. The enzyme showed a sensitivity to thiol-specific inhibitors. During the hydrophobic interaction purification step, the activity dropped considerably. Reactivation occurred when a heat treated crude extract was added to the reaction mixture. 相似文献
4.
Ibolja Cernak Jovan Savic Gordana Zunic Nada Pejnovic Olivera Jovanikic Vladislav Stepic 《World journal of surgery》1999,23(1):44-53
n
= 665, 51%)
had an ISS ranging from 0 to 34 (mean 13) had wounds ranging from G1ST
(soft tissue wounds caused by low energy transfer) to G3VF (massive
wounds with fractures and injury of vital structures) according to the
RCWC, with PSS/IS scores from 2 to 105 (mean 60). Statistically
significant correlation was found between ISS and PSS/IS as well as
RCWC and PSS/IS. Cytokines (IL-1, TNF
alpha
) and amino acids
responded to a blast injury in similar manner as to gunshot wounds with
a greater ISS or more severe RCWC injury type. The subjective
sensations in blasted patients (deafness, thoracic pain, vertigo) and
mediators, confirmed in previous experimental investigations as
important factors in the pathogenesis of blast injuries
(TxA
2
, sulfidopeptide leukotrienes) were relationed only to
the PSS/IS.RID=" ID=" <E5>Correspondence to:</E5> I. Cernak, M.D., Ph.D. 相似文献
5.
Gennadi V. Glinsky Valeri V. Mossine Janet E. Price Diane Bielenberg Vladislav V. Glinsky Honnavara N. Ananthaswamy Milton S. Feather 《Clinical & experimental metastasis》1996,14(3):253-267
We studied the influence of 10 synthetic glycoamine analogs on colony formation in 0.3 and 0.9% agarose by metastatic human breast carcinoma (MDA-MB-435) and melanoma (TXM-13) cells. Nine synthetic analogs significantly inhibited the colony formation in 0.9% agarose of MDA-MB-435 human breast carcinoma cells; five compounds caused a 73–83% reduction of colony formation. Seven synthetic glycoamines caused a significant inhibition of colony formation in 0.9% agarose by TXM-13 melanoma cells with the inhibitory effect ranging from 71 to 87%. The 50% inhibition (I50) doses and relative activity rank of the compounds were similar for both breast carcinoma and melanoma cell lines. The murine B16 melanoma cell aggregation assay was employed to elucidate the potential mechanism(s) of the inhibitory activity of synthetic glycoamines. The relative activity ranks of the compounds based on the independently determined I50 doses for both cell aggregation and clonogenic growth assays were very similar for the four most active synthetic analogs and clearly indicated the importance of hydrophobic amino acid in mediating the bioactivity of synthetic glycoamines. In both experimental systems (clonogenic growth in agarose and cell aggregation assay) the leading compound was N-(1-deoxy-d-fructos-1-y1)-d-leucine (Fru-d-Leu) and the least active analog was N-(1-deoxy-d-fructos-1-yl)-glycine (Fru-Gly). These results show that synthetic glycoamines may act by competing for specific carbohydrate-lectin interactions, particularly those involving -galactoside-specific lectins expressed on metastatic cells. 相似文献
6.
Alexey V. Osipov Vladislav G. Starkov Elena V. Ryumina Leonid V. Kozlov Yvon Doljansky Yuri N. Utkin 《Toxicon》2005,46(4):394-403
Two forms of complement-depleting cobra venom factor (CVFm1 and CVFm2), possessing molecular masses of 142.6 kDa (CVFm1) and 143.1 kDa (CVFm2), according to MALDI mass-spectrometry, were isolated from the Naja melanoleuca cobra venom. As shown by polyacrylamide gel electrophoresis in the presence of SDS, both forms similarly to factor from the Naja kaouthia cobra venom (CVFk) consist of three polypeptide chains with molecular masses of about 70, 50, and 30 kDa, the two large subunits being glycosylated. As determined by MALDI mass-spectrometry, 30 kDa subunits of CVFm1 and CVFm2 have considerably different finger-prints of tryptic digests that suggests differences in their amino acid sequences. A study of activity in vivo has shown no significant differences in C3 consumption by CVFm1, CVFm2 and CVFk in mouse blood. However, as shown by an immunoassay method, they differ in their ability to activate the complement system via C3 conversion, the ratio of these activities for CVFm1:CVFm2:CVFk being 2.5:1.6:1. Kinetic studies using a hemolytic test showed that complement depletion by CVFm1 is faster than that by CVFm2. Thus, for the first time the presence in a single venom of two forms of CVF differing by both amino acid sequence and biological activity has been shown. 相似文献
7.
8.
Andrew Stickley Ai Koyanagi Roman Koposov Yury Razvodovsky Vladislav Ruchkin 《Drug and alcohol dependence》2013
Background
Some evidence suggests that in recent years the prevalence of heavy drinking has increased among Russian adolescents. However, as yet, little is known about either heavy alcohol consumption or its relationship with other adolescent health risk behaviours in Russia. The aim of this study therefore was to investigate the association between binge drinking and health risk behaviours among adolescents in Russia.Methods
Data were drawn from the Social and Health Assessment (SAHA), a survey carried out in Arkhangelsk, Russia in 2003. Information was obtained from a representative sample of 2868 adolescents aged 13–17 regarding the prevalence and frequency of binge drinking (five or more drinks in a row in a couple of hours) and different forms of substance use, risky sexual behaviour and violent behaviour. Logistic regression analysis was used to examine the association between binge drinking and adolescent involvement in various health risk behaviours.Results
Adolescent binge drinking was associated with the occurrence of every type of health risk behaviour – with the sole exception of non-condom use during last sex. In addition, there was a strong association between the number of days on which binge drinking occurred and the prevalence of many health risk behaviours.Conclusions
Binge drinking is associated with a variety of health risk behaviours among adolescents in Russia. Public health interventions such as reducing the affordability and accessibility of alcohol are now needed to reduce binge drinking and its harmful effects on adolescent well-being. 相似文献9.
Fedor M. Zurabov Ekaterina A. Chernevskaya Natalia V. Beloborodova Alexander Yu. Zurabov Marina V. Petrova Mikhail Ya. Yadgarov Valentina M. Popova Oleg E. Fatuev Vladislav E. Zakharchenko Marina M. Gurkova Ekaterina A. Sorokina Egor A. Glazunov Tatiana A. Kochetova Victoria V. Uskevich Artem N. Kuzovlev Andrey V. Grechko 《Viruses》2022,14(12)
Increasing evidence suggests that gut dysbiosis is associated with coronavirus disease 2019 (COVID-19) infection and may persist long after disease resolution. The excessive use of antimicrobials in patients with COVID-19 can lead to additional destruction of the microbiota, as well as to the growth and spread of antimicrobial resistance. The problem of bacterial resistance to antibiotics encourages the search for alternative methods of limiting bacterial growth and restoring the normal balance of the microbiota in the human body. Bacteriophages are promising candidates as potential regulators of the microbiota. In the present study, two complex phage cocktails targeting multiple bacterial species were used in the rehabilitation of thirty patients after COVID-19, and the effectiveness of the bacteriophages against the clinical strain of Klebsiella pneumoniae was evaluated for the first time using real-time visualization on a 3D Cell Explorer microscope. Application of phage cocktails for two weeks showed safety and the absence of adverse effects. An almost threefold statistically significant decrease in the anaerobic imbalance ratio, together with an erythrocyte sedimentation rate (ESR), was detected. This work will serve as a starting point for a broader and more detailed study of the use of phages and their effects on the microbiome. 相似文献
10.
Sergey V. Panin Alexey A. Bogdanov Alexander V. Eremin Dmitry G. Buslovich Vladislav O. Alexenko 《Materials》2022,15(13)
The fatigue properties of neat polyimide and the “polyimide + 10 wt.% milled carbon fibers + 10 wt.% polytetrafluoroethylene” composite were investigated under various cyclic loading conditions. In contrast to most of the reported studies, constructing of hysteresis loops was performed through the strain assessment using the non-contact 2D Digital Image Correlation method. The accumulation of cyclic damage was analyzed by calculating parameters of mechanical hysteresis loops. They were: (i) the energy losses (hysteresis loop area), (ii) the dynamic modulus (proportional to the compliance/stiffness of the material) and (iii) the damping capacity (calculated through the dissipated and total mechanical energies). On average, the reduction in energy losses reached 10–18% at the onset of fracture, whereas the modulus variation did not exceed 2.5% of the nominal value. The energy losses decreased from 20 down to 18 J/m3 (10%) for the composite, whereas they reduced from 30 down to 25 J/m3 (17%) for neat PI in the low-cycle fatigue mode. For high-cycle fatigue, energy losses decreased from 10 to 9 J/m3 (10%) and from 17 to 14 J/m3 (18%) for neat PI and composite, respectively. For this reason, the changes of the energy losses due to hysteresis are of prospects for the characterization of both neat PI and the reinforced PI-based composites. 相似文献