63 research outputs found

    Where does Łódź leak?

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    The text concerns the potential area of cooperation between anthropologists, architects and local community, who lives in space that is to be projected. The city of Łódź faces several urban, economic and political obstacles and problems. The article presents the project, the aim of which was to show that the architecture as a discipline should care about the users of space and ask them about their needs and make them the members of a revitalization project. Therefore, cultural anthropology with its fieldwork methodology is a chance to hear what the people say about the place where they live or would like to live. The authors plan to conduct action research among the inhabitants of Łódź’s backyards and to create a participatory design, which is also aiming at improving civil attitudes

    Biologically Active Constituents from Salix viminalis Bio-Oil and Their Protective Activity Against Hydrogen Peroxide-Induced Oxidative Stress in Chinese Hamster Ovary Cells

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    The protective antioxidative effect of the phenolic extract (PE) isolated from Salix viminalis pyrolysis derived bio-oil was shown in vitro on the Chinese hamster ovary (CHO) cells exposed to hydrogen peroxide (H(2)O(2)). Cells pretreated with 0.05 μg/ml PE after exposure to different concentrations of H(2)O(2) (300–900 μM) showed up to 25 % higher viability than the unpretreated ones. The antioxidative effect of PE was also observed in a time-dependent manner. The results were confirmed by visual examination of the specimens using microscopy. Finally, superoxide dismutase (SOD) activity modulation was shown by SOD assay, designed to determine the activity of enzymes removing free radicals

    State-of-the-art approach towards magnetic resonance imaging of the nervous system structures in patients with cardiac implantable electronic devices

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    Introduction: MRI generated forces are the source of potential complications in patients with cardiac implantable electronic devices (CIED). The technological progress, and growing clinical evidence concerning the operation of the contemporary MR non-conditional CIEDs during MRI, have started to significantly change our every-day clinical practice. Nevertheless, a lot of patients who could have an MRI performed safely, still have been refused the examination. State-of-the-art: In many clinical situations, an MRI examination in a patient with a CIED is reasonable, and is linked to a negligible risk of complications if performed under strict precautions. The MagnaSave Registry that evaluated the influence of nonthoracic MRI on the function of MR non-conditional CIEDs, and numerous studies involving thoracic and nonthoracicMRIs in patients with legacy CIEDs, have confirmed the feasibility and safety of such examinations. In this article, practical tips aimed towards improving the safety of MRI in MR conditional and non-conditional CIED patients are largely based on the very recently released (2017) HRS expert consensus statement. Clinical implications: Clinical data emphasize the necessity of making the MRI more accessible to CIED patients, also in the case of MR non-conditional systems or when the thorax MR imaging is clinically reasonable. This goal should be achieved by increasing the number of centers complying with respective recommendations and applying protocols that would guarantee the highest safety level. Future directions: Further studies are warranted to assess safety issues related to the main current contraindication to MRI, i.e., the presence of abandoned leads

    Female versus male : Rumex thyrsiflorus Fingerh. under in vitro conditions : does sex influence in vitro morphogenesis?

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    Rumex thyrsiflorus Fingerh. is a dioecious plant with polymorphic sex chromosomes (XX in females, XY_{1}Y_{2} in males). This species is an interesting plant for study on the structure and function of sex chromosomes, the sex ratio, and is also a valuable source of bioactive constituents. A procedure for the micropropagation of R. thyrsiflorus from hypocotyl explants, which can be useful for analyses of sex-specific morphogenetic reactions under in vitro conditions, was developed. The molecular analysis, based on genetic sex markers, allowed the sex of explants to be determined in order to create male or female in vitro cultures. Regeneration primarily occurred via indirect adventitious shoot formation as well as via somatic embryogenesis, which was confirmed by histological and scanning electron microscope (SEM) analyses. The highest frequency of explants that revealed a morphogenetic response with the highest number of regenerated adventitious shoot buds (average 11.5 shoots per explant) was obtained on a Murashige and Skoog (MS) medium supplemented with 2.27 \mu M thidiazuron (TDZ). Molecular analysis revealed a female-biased sex ratio under these conditions. The relationship between the sex of the explants and their morphogenetic potential was studied. The efficiency of morphogenesis varied between the two sexes and depended on the ratio of auxin and cytokinin in the medium. The germination pattern of male and female seeds under in vitro conditions was also analysed. No differences in germination time between male and female seeds and in terms of male and female seedling length were observed, which indicated that there was no competition between the sexes during seed germination when grown under uniform growth conditions

    Immunohistochemical and hybridocytochemical study on ghrelin signalling in the rat seminiferous epithelium.

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    The results of presented study demonstrate expression of ghrelin, its functional receptor GHSR-1a and their genes in spermatogenic cells of rat testis suggesting their functioning within seminiferous epithelium. The immunohistochemical and hybrydocytochemical expression, of proteins and transcripts, was estimated taking into account the cycle of seminiferous epithelium and phases of spermatogenesis. Both transcripts and ghrelin was found to show nuclear expression and scarcely cytoplasmic. Expression of genes for ghrelin and GHSR-1a was shown in early spermatocytes and round spermatids representing transcriptional phases of meiosis and spermiogenesis. Ghrelin was evidenced to show nuclear expression in two stage-specific windows, in late spermatogonia, in spermatocytes up to early pachytenes, and again in spermatids of acrosome and early maturation phase of spermiogenesis. In late pachytenes, secondary spermatocytes, round spermatids, maturing spermatids and spermatozoa the reaction is lacking. With two types of antibodies against the GHSR-1a used the two different patterns of immunostaining was evidenced suggesting two isoforms of GHSR-1a. The first evidenced GHSR-1a in cytoplasm of spermatocytes, cell membrane and acrosomes of spermatids, Sertoli cell processes and heads of spermatozoa. With second type of antibodies the immunostaining marks all steps of evolution of acrosome in spermatids. It is believed that site of ghrelin expression in seminiferous epithelium may indicate its role in local regulations, not excepting the intracellular signalling. Immunostaining pattern for GHSR-1a seems to suggest both its participation in the cross-talk among the cells and also process of furnishing gametes with GHSR-1a for its response to ghrelin in seminal plasma or female reproductive tract

    Surface chemistry and structural properties of proton-beam irradiated graphene oxide paper

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    Graphene oxide (GO) is a promising material for the futuregraphene-based electronics where the surface chemistry and structural properties of GO may play an important role. One of the unique methods with great potentialfor controllable modification of materials’ properties is the ion beam irradiation. In the present study, GO paper was irradiated with 15 keV proton- beam to a fluences from 5×10 16 to 2×1017 ionscm-2 , while Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray photoelectronspectroscopy (XPS) and Raman spectroscopy (RS)were used for the examination of surface chemistry and structural properties of the irradiated material. It was shown that proton beam irradiation leads to a partial reduction of GOwith the preferential removal of the alkoxy and epoxy groups. With the increasing fluence, the oxygen content from the XPS method and the intensity ratioof D and G Raman bandsboth showed decreasing trends. When oxygen content was compared to relative areas of specific functional groups and parameters of Raman peaks an interesting correlation was found that suggest optimal fluences for tuning the surface chemistry and structural properties of GO. The observed effects on surface chemistry and structural propertiescan be ascribed to physical and chemical effectsof ion beam irradiation. The interaction of functional groups with H-atom was investigated using DFT andsemi-empirical (SE) approach. SE calculations revealed that the reduction of the epoxy group appears at H-atom energies below 1.5 eV. This work identifies ion beam irradiation as a preferable technique for selective removal of surface oxygen groups and structural modification of GO where the applied fluence can be used for tuning the degree of change.IX Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 20-21, 2021; Belgrad

    Surface, structural and electric properties of ion beam irradiated graphene oxide papers

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    Graphene oxide (GO) has emerged as a promising material for electrochemical charge storage due to its high capacitance originating from all-surface morphology and different oxygen groups that participate in redox reactions. Ion beam irradiation can be identified as a technique where a controllable change of surface chemistry and structure of GO is possible through varying the energy and the fluence of an ion beam. In the present study, the influence of keV-energy ion-beam irradiation on the surface chemistry, structural and electrical properties of GO paper were investigated. The results of X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy showed an increasing reduction of GO and the preferential removal of the alkoxy and epoxy groups with increasing fluence. Raman analysis showed that there is clear correlation between oxygen content and structural parameters of the irradiated GO. Electric properties of ion beam irradiated GO papers were investigated using the solid-state electrochemical impedance spectroscopy (EIS) and compared to the effects of thermal treatment. With irradiation, lower resistivity of GO papers was observed with fluencies up to 1 × 10 16 ions/cm 2 proving that desorption of basal plane oxygen groups is beneficial for improvement of electric characteristics of material. At higher fluence, a higher defect concentration resulted in an increase of resistivity of the irradiated samples. Additionally, EIS results outlined a different behavior of ion beam irradiated and thermally treated samples (capacitor vs. resistor, respectively), originating from the different extent of modification (ion beam irradiation – modification of few hundred nm and thermal treatment – bulk modification).Nineteenth Young Researchers' Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbi

    Modification of surface oxygen groups of graphene oxide by ion beam irradiation for supercapacitor applications

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    Surface oxygen groups may have a significant impact on the electrochemical charge storage properties of graphene oxide (GO). The presence of these groups on GO should be properly balanced so that electronic conductivity is optimized, while only the groups that are beneficial to capacitance are preserved. Ion beam irradiation can be identified as a technique where a controllable change of surface chemistry and structure of GO is possible through varying the energy and the fluence of an ion beam. In the present study, the influence of proton-beam irradiation on the surface chemistry and structural properties of GO paper was investigated. GO paper was irradiated with 15 keV proton-beam to fluences from 5×1016 to 2×1017 ions cm-2, while Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy (RS) were used for the analysis of the surface chemistry and structural properties. Results indicate increasing reduction of surface oxygen groups and the preferential removal of the alkoxy and epoxy groups as fluence increased. Desorption of these basal plane groups was outlined in our previous work as important for charge storage capacity, probably due to conductivity increase [1]. When oxygen content was compared to: 1) relative areas of specific functional groups from FTIR and XPS and 2) parameters of Raman peaks, an interesting correlation was found that suggest optimal fluences for tuning the surface chemistry and structural properties of GO. Modification of surface chemistry originates from the physical and chemical effects of ion beam irradiation which were also investigated theoretically. The interaction of functional groups with H-atom was investigated using DFT and semi-empirical (SE) approach. SE calculations revealed that the chemical reduction of the epoxy group appears at H-atom energies below 1.5 eV. Results indicate that ion-beam irradiation can be used for controllable modification of surface chemistry of GO where the applied fluence can be used for tuning the degree of change, which may have implications to electrochemical charge storage properties.4th International Meeting on Materials Science for Energy Related Applications, September 22-23, 2021, Belgrade, Serbi
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