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9422. Studies on the effect of the proppant embedment phenomenon on the effective packed fracture in shale rock
- Creator:
- Maslowski, Mateusz, Kasza, Piotr, and Wilk, Klaudia
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- geodynamika, geomechanika, geofyzika, geologie, geodynamics, geomechanics, geophysics, geology, břidlice, fracture width, embedment, hydraulic fracturing, shale, proppant, effective packed fracture, 7, and 551
- Language:
- English
- Description:
- This paper presents the subject related to the technology of creating fractures into a rock, as well as the subject related to the effect of the proppant embedment phenomenon on the effective packed fracture in a reservoir rock. This phenomenon occurs after the performed hydraulic fracturing treatment of hydrocarbon reservoirs, during closing of the rock mass. A key part of this experiment was to investigate the depth of proppant grains penetration into the fracture wall (shale rock) and size of damage to the fracture wall surface. The embedment phenomena effects on decrease in the width fracture packed with proppant. The tests were performed for shale rock initially soaked with fracturing fluid, lightweight ceramic proppant grains with a grain size of 0.600÷0.300 mm (medium diameter of proppant grains of 0.450 mm), low surface concentration of proppant of 2.44 kg/m2. Time of exposure of proppant grains to compressive stress of a value 48.3 MPa for 6 hours at 70 oC. Test results indicate that the developed testing methodology may be used for corrected evaluation of the fracturing fluid as well as proppant in hydraulic fracturing treatment of unconventional reservoirs, especially shale rocks. and Maslowski Mateusz, Kasza Piotr, Wilk Klaudia.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
9423. Studies on the transovarial transmission of Borrelia burgdorferi sensu lato in the taiga tick Ixodes persulcatus
- Creator:
- Nefedova, Valentina V., Korenberg, Edward I., Gorelova, Nataliya B., and Kovalevskii, Yury V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Borrelia burgdorferi, Ixodes persulcatus, ticks, and transovarial transmission
- Language:
- English
- Description:
- The possibility of vertical transmission of Borrelia burgdorferi sensu lato in Ixodes persulcatus Schulze, 1930 ticks was studied in the progeny of 20 females collected from the vegetation in an active focus of ixodid tick-borne borrelioses (ITBB) located in the Perm oblast, Russia, where Borrelia garinii and B. afzelii are circulating. The presence of Borrelia DNA was detected by the PCR method after feeding and egg laying in 16 engorged females (80.0%), as well as in 36.5 ± 7.2% samples containing 20 eggs each and in 21.4 ± 4.2% samples containing 10 eggs each. The respective rates of individual egg infection were 0.4-8.0% and 0.5-23.0%. PCR analysis of 370 eggs (one egg per sample) and 781 unfed larvae hatched from the same egg masses (1, 10, 20, 40, and 50 larvae per sample) failed to reveal the presence of Borrelia DNA. Negative results were also obtained in experiments on inoculating the BSK II medium with the egg and larval materials. Microscopic analysis of 1,683 smear preparations of eggs and 1,416 preparations of unfed daughter larvae revealed spirochete-like cells in 7 (0.4 ± 0.3%) and 13 (0.9 ± 0.5%) preparations, respectively; typical Borrelia cells were found in seven preparations of larvae (0.5 ± 0.4%). Only 1 out of 16 infected females transmitted Borrelia vertically, through the eggs to the larval progeny. The infection rate in this progeny was about 7%, and the prevalence of Borrelia in individual larvae was 0.4-0.8 cells per 100 microscopic fields. These data do not allow the conclusion that transovarial transmission of B. burgdorferi sensu lato in the I. persulcatus tick is an established fact. However, they show that, even if such transmission is possible, its probability is very low.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9424. Studies on transmission and life cycle of Enteromyxum scophthalmi (Myxozoa), an enteric parasite of turbot Scophthalmus maximus
- Creator:
- Redondo, María J., Palenzuela, Oswaldo, and Alvarez-Pellitero, Pilar
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Myxozoa, Myxosporea, Enteromyxum, life cycle, transmission, turbot, intestinal explants, and in vitro
- Language:
- English
- Description:
- In order to elucidate the transmission and dispersion routes used by the myxozoan parasite Enteromyxum scophthalmi Palenzuela, Redondo et Alvarez-Pellitero, 2002 within its host (Scophthalmus maximus L.), a detailed study of the course of natural and experimental infections was carried out. Purified stages obtained from infected fish were also used in in vitro assays with explants of uninfected intestinal epithelium. The parasites can contact and penetrate loci in the intestinal epithelium very quickly. From there, they proliferate and spread to the rest of the digestive system, generally in an antero-posterior pattern. The dispersion routes include both the detachment of epithelium containing proliferative stages to the intestinal lumen and the breaching of the subepithelial connective system and local capillary networks. The former mechanism is also responsible for the release of viable proliferative stages to the water, where they can reach new fish hosts. The finding of parasite stages in blood smears, haematopoietic organs, muscular tissue, heart and, less frequently, skin and gills, suggests the existence of additional infection routes in transmission, especially in spontaneous infections, and indicates the role of vascular system in parasite dispersion within the fish. The very high virulence of this species in turbot and the rare development of mature spores in this fish may suggest it is an accidental host for this parasite. This may also question the existence of a two-host life cycle involving an actinosporean stage in this species. Further studies are needed to clarify this open point of the life cycle.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9425. Studium antiferomagnetů pomocí ultrarychlé laserové spektroskopie
- Creator:
- Saidl, Vít, Němec, Petr, Trojánek, František, and Malý, Petr
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fyzika, laserová spektroskopie, antiferomagnety, atmospheric physics, laser spectroscopy, antiferromagnets, 6, and 53
- Language:
- Czech and English
- Description:
- Antiferomagnetické materiály mají velky potenciál pro konstrukci počítačových součastek nové generace. Nepřítomnost makroskopického magnetického momentu nicméně v těchto materiálech silně komplikuje studium jejich magnetických vlastností. V tomto článku popisujeme novou magnetooptickou metodu, která umožňuje zkoumat tenké kovové antiferomagnetické filmy pomocí femtosekundových laserových pulzů. Za vyvinutí této experimentální metody obdržel v roce 2017 V. Saidl cenu Česká hlava v kategorii Doctorandus - technické vědy., Antiferromagnetic materials have great potential for the development of a new generation of computer devices. However, the absence of net magnetic moment in these materials significantly complicates the investigation of their magnetic properties. In this article we present a new magneto-optical technique, which enables the study of thin films of antiferromagnetic metals by femtosecond laser pulses. In 2017 V. Saidl received the Czech head award, in the Doctorandus category, for the development of this experimental technique., Vít Saidl, Petr Němec, František Trojánek, Petr Malý., and Obsahuje použitou literaturu
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9426. Štúdium interakcie cytochrómu c s kalixarénmi zabudovanými do lipidových membrán
- Creator:
- Hianik, Tibor, Garaiová, Zuzana, Vargová, Veronika, and Vitovič, Pavol
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- cytochromy, lipozomy, biofyzika, cytochromes, liposomes, biophysics, 6, and 53
- Language:
- Czech and English
- Description:
- We studied the interaction of cytochrome c (cyt c) with unilamellar liposomes (ULL) composed of dimyristoylphosphatidylcholine (DMPC) modified by calix[6]arene (CX). We also analyzed the influence of cyt c on the properties of monomolecular films on an air-water interface composed of CX. The changes of the liposome size have been studied by dynamic light scattering and the zeta potential was determined by Doppler velocimetry. By ultrasound attenuation coefficient we also studied the effect of CX on the phase transition of the lipid bilayer of liposomes. The liposomes containing 10mol% CX have been on average 1.5 times larger in comparison with unmodified ULL. The increase of ULL diameter has been accompanied by a decrease of zeta potential toward negative values. This has been due to negatively charged carboxyl groups of CX polar part. The interaction of cyt c with CX resulted in an increase of zeta potential. CX did not affect the phase transition temperature of liposomes (T = 24.4 °C). However, the half width of the transition peak increased which is evidence of a decrease of the cooperativity of phase transition. CX forms stable monomolecular films on the air-water interphase. The presence of cyt c in a water subphase caused an increase of mean molecular area of CX. The dependence of relative changes of the area per molecule as a function of cyt c concentration had the shape of Langmuir isotherm. The dissociation constant, KD, determined in a solid state of the monolayer was 26.0 ± 5.4 nM, which is evidence of good affinity of cyt c to CX., Tibor Hianik, Zuzana Garaiová, Veronika Vargová, Pavol Vitovič., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9427. Studium povrchů a rozhraní
- Creator:
- Svoboda, Pavel and Jungwirth, Tomáš
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fyzika, povrchy, physics, surfaces, 6, and 53
- Language:
- Czech and English
- Description:
- Pavel Svoboda, Tomáš Jungwirth.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9428. Štúdium proteínov pomocou optického silomera
- Creator:
- Žoldák, Gabriel
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- optické systémy, bílkoviny, optical systems, proteins, 6, and 53
- Language:
- Czech and English
- Description:
- Ohromujúci vývoj laserových optických metód umožnil širokú plejádu manipulácií s objektmi pomocou svetelného lúča a ďalej podnietil vývoj experimentálnych postupov umožňujúcich zachytiť subpikonewtonovské sily medzi molekulami. Aplikácia optického silomera pri štúdiu vlastností biomakromolekúl nám pomáha chápať fyzikálne princípy mechanickej funkcie týchto komplexných nanometrových objektov., The extensive development of laser technology has enabled a large variety of object manipulations with light. This has initiated the development of experimental assays for the detection of sub piconewton forces between molecules. The application of an optical force meter for the study of bio-macromolecules reveals elementary physical principles of the mechanical function of these complex nano sized objects., Gabriel Žoldák., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9429. Study abroad experience and attitudes towards other nationalities
- Creator:
- Cahlíková, Jana
- Publisher:
- CERGE-EI
- Format:
- electronic, bez média, svazek, and 47 stran : ilustrace, mapy.
- Type:
- model:monograph and TEXT
- Subject:
- Sociální interakce. Sociální komunikace, zahraniční studium, výměna studentů, národní identita, regionální identita, sociologický výzkum, foreign study, student exchange programs, national identity, regional identity, sociological research, 37.018.556, 37.014.242, 316.347, 316.72:323.174, 316:303, (048.8), 18, and 316.4/.7
- Language:
- English and Czech
- Description:
- Jana Cahlíková., Obsahuje bibliografii a bibliografické odkazy, and České resumé
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9430. Study of abberant modifications in peptides as a test bench to investigate the immunological response to non-enzymatic glycation
- Creator:
- Nuti, F., Gallo, A., Real-Fernandez, F., Rentier, C., Rossi, G., Piarulli, F., Traldi, P., Carganico, S., Rovero, P., Lapolla, A., and Papini, A. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- protein glycation, immunological response, peptide, β-turn peptide structure, type 1 diabetes, and SP-ELISA
- Language:
- English
- Description:
- A side effect of diabetes is formation of glycated proteins and, from them, production of advanced early glycation end products that could determine aberrant immune responses at the systemic level. We investigated a relevant aberrant post-translational modification (PTM) in diabetes based on synthetic peptides modified on the lysine side chain residues with 1-deoxyfructopyranosyl moiety as a possible modification related to glycation. The PTM peptides were used as molecular probes for detection of possible specific autoantibodies developed by diabetic patients. The PDC-E2(167-186) sequence from the pyruvate dehydrogenase complex was selected and tested as a candidate peptide for antibody detection. The structure-based designed type I’ β-turn CSF114 peptide was also used as a synthetic scaffold. Twenty-seven consecutive type 1 diabetic patients and 29 healthy controls were recruited for the study. In principle, the ‘chemical reverse approach’, based on the use of patient sera to screen the synthetic modified peptides, leads to the identification of specific probes able to characterize highly specific autoantibodies as disease biomarkers of autoimmune disorders. Quite surprisingly, both peptides modified with the (1-deoxyfructosyl)-lysine did not lead to significant results. Both IgG and IgM differences between the two populations were not significant. These data can be rationalized considering that i) IgGs in diabetic subjects exhibit a high degree of glycation, leading to decreased functionality; ii) IgGs in diabetic subjects exhibit a privileged response vs proteins containing advanced glycation products (e.g., methylglyoxal, glyoxal, glucosone, hydroimidazolone, dihydroxyimidazolidine) and only a minor one with respect to (1-deoxyfructosyl)-lysine. and Corresponding authors: Anna Maria Papini; Annunziata Lapolla
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public