449 research outputs found

    Zeolite-based photocatalysts immobilized on aluminum support by plasma electrolytic oxidation

    Full text link
    The preparation and properties of zeolite-containing oxide coatings obtained by plasma electrolytic oxidation are investigated and discussed. Pure and Ce-exchanged natural (clinoptilolite) and synthetic (13X) zeolites are immobilized on aluminum support from silicate-based electrolyte. Obtained coatings are characterized with respect to their morphology, phase and chemical composition, photocatalytic activity and anti-corrosion properties. It is observed that all mentioned properties of obtained coatings are dependent on processing time and type of immobilized zeolite. Coatings with Ce-exchanged zeolite show higher photocatalytic activity and more effective corrosion protection than those with pure zeolite. The highest photocatalytic activity is observed for coatings processed in pulsed a DC regime for 30 minutes containing Ce-exchanged 13X zeolite, followed by those containing Ce-exchanged clinoptilolite. Pronounced anti-corrosion properties feature almost all samples containing Ce-exchanged 13X zeolite

    Evaluation of the collaborative network of highly correlating skin proteins and its change following treatment with glucocorticoids

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Glucocorticoids (GC) represent the core treatment modality for many inflammatory diseases. Its mode of action is difficult to grasp, not least because it includes direct modulation of many components of the extracellular matrix as well as complex anti-inflammatory effects. Protein expression profile of skin proteins is being changed with topical application of GC, however, the knowledge about singular markers in this regard is only patchy and collaboration is ill defined.</p> <p>Material/Methods</p> <p>Scar formation was observed under different doses of GC, which were locally applied on the back skin of mice (1 to 3 weeks). After euthanasia we analyzed protein expression of collagen I and III (picrosirius) in scar tissue together with 16 additional protein markers, which are involved in wound healing, with immunhistochemistry. For assessing GC's effect on co-expression we compared our results with a model of random figures to estimate how many significant correlations should be expected by chance.</p> <p>Results</p> <p>GC altered collagen and protein expression with distinct results in different areas of investigation. Most often we observed a reduced expression after application of low dose GC. In the scar infiltrate a multivariate analysis confirmed the significant impact of both GC concentrations. Calculation of Spearman's correlation coefficient similarly resulted in a significant impact of GC, and furthermore, offered the possibility to grasp the entire interactive profile in between all variables studied. The biological markers, which were connected by significant correlations could be arranged in a highly cross-linked network that involved most of the markers measured. A marker highly cross-linked with more than 3 significant correlations was indicated by a higher variation of all its correlations to the other variables, resulting in a standard deviation of > 0.2.</p> <p>Conclusion</p> <p>In addition to immunohistochemical analysis of single protein markers multivariate analysis of co-expressions by use of correlation coefficients reveals the complexity of biological relationships and identifies complex biological effects of GC on skin scarring. Depiction of collaborative clusters will help to understand functional pathways. The functional importance of highly cross-linked proteins will have to be proven in subsequent studies.</p

    Properties of ZnO/ZnAl2_2O4_4 composite PEO coatings on zinc

    Full text link
    Recently the successful formation of PEO coatings on zinc in a phosphate aluminate electrolyte was shown. The produced composite coatings contain various mixtures of ZnO and ZnAl2_2O4_4. In frame of the current study, the properties of the formed coatings including adhesion/cohesion, wear, corrosion and photocatalytic activity were analysed to identify possible applications. However, the coatings show internal porosity and a sponge-like structure. Thus the cohesion within the coating is quite low. Pull-off tests have demonstrated clear rupture within the PEO layer at strength values as low as 1 MPa. The photocatalytic activity is limited, in spite of the formation of a higher amount of ZnO at shorter treatment times. Interestingly, the composite coatings of ZnO and higher amounts of ZnAl2_2O4_4 spinel showed a higher activity, but not sufficient for fast and effective catalytic cleaning applications

    Primary cultured fibroblasts derived from patients with chronic wounds: a methodology to produce human cell lines and test putative growth factor therapy such as GMCSF

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Multiple physiologic impairments are responsible for chronic wounds. A cell line grown which retains its phenotype from patient wounds would provide means of testing new therapies. Clinical information on patients from whom cells were grown can provide insights into mechanisms of specific disease such as diabetes or biological processes such as aging.</p> <p>The objective of this study was 1) To culture human cells derived from patients with chronic wounds and to test the effects of putative therapies, Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) on these cells. 2) To describe a methodology to create fibroblast cell lines from patients with chronic wounds.</p> <p>Methods</p> <p>Patient biopsies were obtained from 3 distinct locations on venous ulcers. Fibroblasts derived from different wound locations were tested for their migration capacities without stimulators and in response to GM-CSF. Another portion of the patient biopsy was used to develop primary fibroblast cultures after rigorous passage and antimicrobial testing.</p> <p>Results</p> <p>Fibroblasts from the non-healing edge had almost no migration capacity, wound base fibroblasts were intermediate, and fibroblasts derived from the healing edge had a capacity to migrate similar to healthy, normal, primary dermal fibroblasts. Non-healing edge fibroblasts did not respond to GM-CSF. Six fibroblast cell lines are currently available at the National Institute on Aging (NIA) Cell Repository.</p> <p>Conclusion</p> <p>We conclude that primary cells from chronic ulcers can be established in culture and that they maintain their <it>in vivo </it>phenotype. These cells can be utilized for evaluating the effects of wound healing stimulators <it>in vitro</it>.</p

    The Utility of ctDNA in Lung Cancer Clinical Research and Practice: A Systematic Review and Meta-Analysis of Clinical Studies.

    Get PDF
    This systematic review with embedded meta-analysis aimed to evaluate the clinical utility of circulating tumor DNA (ctDNA) in lung cancer. After screening and review of the Embase database search, 111 studies from 2015 to 2020 demonstrated ctDNA's value in prognostication/monitoring disease progression, mainly in patients with advanced/metastatic disease and non-small cell lung cancer. ctDNA positivity/detection at any time point was associated with shorter progression-free survival and overall survival, whereas ctDNA clearance/decrease during treatment was associated with a lower risk of progression and death. Validating these findings and addressing challenges regarding ctDNA testing integration into clinical practice will require further research

    Use of an orthovoltage X-ray treatment unit as a radiation research system in a small-animal cancer model

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer.</p> <p>Methods</p> <p>Nude mice were subcutaneously inoculated with 5 × 10<sup>6 </sup>HeLa cells in both lower limbs. When tumor volume approximated 200 mm<sup>3 </sup>treatment was initiated. Animals received four 2 mg/kg intraperitoneal cycles (1/week) of cisplatin and/or 6.25 mg/kg of gemcitabine, concomitant with radiotherapy. Tumors were exposed to 2.5 Gy/day nominal surface doses (20 days) of 150 kV X-rays. Lead collimators with circular apertures (0.5 to 1.5 cm diameter) were manufactured and mounted on the applicator cone to restrict the X-ray beam onto tumors. X-ray penetration and conformality were evaluated by measuring dose at the surface and behind the tumor lobe by using HS GafChromic film. Relative changes in tumor volume (RTV) and a clonogenic assay were used to evaluate the therapeutic response of the tumor, and relative weight loss was used to assess toxicity of the treatments.</p> <p>Results</p> <p>No measurable dose was delivered outside of the collimator apertures. The analysis suggests that dose inhomogeneities in the tumor reach up to ± 11.5% around the mean tumor dose value, which was estimated as 2.2 Gy/day. Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.</p> <p>Conclusion</p> <p>Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.</p

    Thyrotropin-releasing hormone (TRH) promotes wound re-epithelialisation in frog and human skin

    Get PDF
    There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters
    corecore