Biography:

In the past J. Karczewski has collaborated on articles with B. Bochentyn and M. Karczewski. One of their most recent publications is Regular ArticleAn Inhibitor from the Argasid Tick Ornithodoros moubata of Cell Adhesion to Collagen. Which was published in journal Biochemical and Biophysical Research Communications.

More information about J. Karczewski research including statistics on their citations can be found on their Copernicus Academic profile page.

J. Karczewski's Articles: (12)

Regular ArticleAn Inhibitor from the Argasid Tick Ornithodoros moubata of Cell Adhesion to Collagen

AbstractAn inhibitor of the adhesion of human platelets to collagen was identified in soluble extracts of the soft tick Ornithodoros Moubata and purified by four chromatographic steps. The isolated inhibitor, TAI (Tick Adhesion Inhibitor), is a ∼15-kDa protein that completely blocks the adhesion of platelets to collagen-coated microtiter plates with an IC50 of 8 nM. In the same concentration range it does not inhibit collagen-induced platelet aggregation or platelet adhesion to fibrinogen and has a partial inhibitory effect on platelet adhesion to fibronectin. TAI also blocks the adhesion of human endothelial cells to collagen, thus its inhibitory effect is not limited to platelets. TAI competes for the binding to platelets of a radiolabeled monoclonal antibody against the platelet glycoprotein Ia-IIa integrin complex. Based on its selective activity and small size, TAI is a promising new molecule for exploring cell-collagen interactions.

Characterization of structural, thermal and mechanical properties of bismuth silicate glasses

Highlights•Reduction in hydrogen leads to formation of layer on the glass surface.•Layer is formed by granules of metallic bismuth embedded in a glass matrix.•Metallic bismuth melts during heating of a previously reduced glass sample.•Reduction in hydrogen prevents the glass softening.

Renal transplantationAcute rejectionRole of TH1/TH2 Cytokines in Kidney Allograft Rejection

AbstractOne of the major issues in contemporary kidney transplantation is prevention of acute allograft rejection episodes (AREs). Cytokines are crucial mediators of immune reactions leading to AREs. We correlated serum Th1/Th2 cytokine concentrations with AREs. The project included 44 patients undergoing kidney transplantation. During the 3-month period following the transplantation, ARE was diagnosed in 11 patients. Serum samples collected 1 day before and 2, 7, 14, and 30 days after transplantation were tested for interleukin (IL)-2, IL-4, IL-5, IL-10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α concentrations using flow cytometry. Nonrejection (NONAR) and rejection (ARE) groups of patients did not show significant differences in baseline demographic characteristics. We observed that higher pretransplantation serum levels of IFN-γ (P = .000003) and IL-10 (P = .000001) were associated with AREs. Our analysis also showed slightly higher IL-4 serum levels among NONAR patients up to 7 days posttransplantation, followed by a drop in concentrations in NONAR patients. In contrast, there was a continuous increase among ARE patients. No significant differences were observed in plasma levels of IL-2, IL-5, IL-10, or TNF-α between the two groups. Higher pretransplantation levels of IFN-γ and IL-10 observed in ARE patients indicated ongoing nondetected, probably nonspecific, inflammatory processes able to intensify an immune response directed against the transplanted organ leading to its acute rejection. Higher levels of IL-4 prior to and shortly after transplantation may have protective effects on graft survival. However, a prolonged, increased production of IL-4 after transplantation can also contribute to AREs.

Kidney transplantationComplicationsUrologic De Novo Malignancies After Kidney Transplantation: A Single Center Experience

AbstractIntroductionUrologic cancers are the second or third most common malignancies in renal transplant (RT) recipients. This study sought to determine the incidence of and identify possible risk factors for urologic malignancies among patients who underwent transplantation at our center.MethodsThis retrospective, single-center cohort included 836 patients who underwent transplantation from 1994 to 2011 who remained under our care. A review of their medical records revealed 63 subjects with de novo cancer, including 21 with urologic malignancies (2.5%). We analyzed demographic and clinical data of cancer versus noncancer patients with differences considered to be significant at P < .05.ResultsThe urologic malignancies included renal cell carcinoma (n = 13), prostate cancer (n = 5), and bladder transitional cell carcinoma (n = 3). The mean follow-up time was 10 ± 3.9 years. The mean age at diagnosis was 54 ± 7.4 years and the mean time from transplantation was 4 ± 3.3 years. The mortality rate among group was 19.0%. The analysis did not show significant differences in demographic or clinical characteristics between the groups, except for the prevalence of male gender and smoking status among the cancer cohort. No significant differences were observed for other suspected risk factors, including immunosuppressive protocols, time of pretransplantation dialysis, and age.ConclusionsThe development of urologic malignancies is an early event, frequently observed within 4–5 years after transplantation. Therefore, this period should be considered for routine urologic cancer screening.

Solid oxide fuel cells with Ni-infiltrated perovskite anode

AbstractNiobium-doped strontium titanate was used as the anode for a solid oxide fuel cell. Electrolyte-supported cells were prepared with pure perovskite and composite perovskite–yttria–stabilized-zirconia (YSZ) anodes. Fuel cell tests demonstrated significant improvement in power density after infiltration with a small amount of Ni. The obtained values of power densities are comparable with conventional Ni/YSZ cermet anode. In addition, stability tests showed initial degradation followed by stable operation.

Electronic and ionic relaxations in strontium–borate glass and glass-ceramics containing bismuth and vanadium oxides

Highlights•SBO glasses with bismuth and vanadium oxides consist of two amorphous phases.•No para-ferroelectric phase transition is observed in tested materials.•Conduction mechanism at low temperatures is mixed electronic and ionic.•At high-temperature region, the dominating conduction mechanism is ionic.

High temperature corrosion and corrosion protection of porous Ni22Cr alloys

Highlights•corrosion kinetics of porous IN625 alloy is studied in the temperature range of 700 °C–800 °C•corrosion kinetics of porous IN625 alloy is studied in air and hydrogen atmosphere for up to 1000 h•method of reducing corrosion rates of porous alloys by the infiltration of rare earths elements (Y, La, Gd, Ce) is shown•modification by the yttrium precursor reduces corrosion rate by a factor of 50

Review ArticleStatus report on high temperature fuel cells in Poland – Recent advances and achievements

Highlights•Advances in SOFC and MCFC are presented and discussed.•Experimental and numerical studies are presented.•New materials and fabrication methods are reported.•Selected applications are discussed.

Electrochemical properties of porous Sr0.86Ti0.65Fe0.35O3 oxygen electrodes in solid oxide cells: Impedance study of symmetrical electrodes

Highlights•Formation of a dense interface layer for sintering temperature >1000 °C.•Polarization resistance is independent of the calcination temperature.•Performance of the porous STF35 electrode is limited by oxygen adsorption.

Structure and thermoelectric properties of Bi–Te alloys obtained by novel method of oxide substrates reduction

Highlights•Reduction of oxide substrates allows to fabricate thermoelectric Bi–Te alloys.•Final composition and microstructure can be controlled by parameters of reduction.•Thermoelectric properties of Bi–Te alloys differ depending on reduction temperature.•The highest figure of merit shows 20Bi2O3–80TeO2 compound reduced at 400 °C for 10 h.

The Properties of Reduced Bi-Ge-O Glasses for Thermoelectric Devices☆

AbstractThe bismuth-germanate glasses have been investigated to examine their applicability for thermoelectric devices. In order to increase their electrical conductivity, the 25Bi2O3–75GeO2 glass samples have been reduced at 340-380 °C for 10 hours in hydrogen. It has been shown that such heat treatment in H2 leads to the reduction of metal ions Bi3+ and Ge4+ into neutral atoms and the formation of metal grains both in an amorphous glass matrix and on the glass surface. The bulk electrical conductivity of the reduced 25Bi2O3–75GeO2 sample measured at 100 °C is ∼ 2.6 Scm-1, whereas the Seebeck coefficient of this glass estimated in a temperature range 20-100 °C in reference to Pt is α=(-57.5±0.5) μVK-1.

Microstructure and Dielectric Properties of Barium-vanadate Glasses☆

AbstractThe ac and dc conductivity in barium-vanadate glasses was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD results show that all samples are amorphous but microscopy investigation reveals that glasses with greater amount of V2O5 contain nanostructures. The influence of V2O5 quantity on dielectric properties was checked. The activation energy of dc conduction process was evaluated. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity parameters were determined and compared to theoretical models collected by Elliott.

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