226 research outputs found
THE EVALUATION OF INHIBITORY EFFECTS OF SELECTED PLANT EXTRACTS ON ANTIOXIDANT ENZYMES
No full textYildirim, Ozlem/0000-0003-1018-0335; Isgor, belgin S/0000-0001-5716-3159; Isgor, Yasemin G./0000-0002-6021-257XPlants and most of the plant derived compounds have been known because of their potential pharmaceutical effects for a long time. They are playing an important role on the treatment of several diseases from diabetes to various types of cancers. Today most of the clinically effective pharmaceuticals are developed from plant derived ancestors in the history of medicine. In this study different parts of the plants, namely Centaurea virgata (Lam.), Cichorium intybus (L.), Euporbia macroclada (Boiss.), Melilotus of ficinalis (L.) Pall. and Zygophyllum fabago (L.) were evaluated for their potential medicinal value in terms of biological targets which are participating in antioxidant defense such as catalase (CAT), glutathione-S-transferase (GST), superoxide dismutase (SOD) and glutathione peroxidase (GPx). The results indicate that the highest total phenolic contents of leaf and flower extracts were for E. macroclada. The highest flavonoid contents are detected for the leaves of E. macroclada and Z. fabago. The evaluation of extracts against biological targets reveals that the fruit extract of Z. fabago and the flowers of C. intybus show the inhibition against GST. For CAT, the highest inhibition is observed with E. macroclada leaf extract. Among the extracts analyzed, the only but slight SOD inhibition is determined with flower part of E. macroclada.Ankara University [BAP-13L4240003]; Atilim University Biochemistry Research Laboratory InfrastructureThis work was supported by Ankara University BAP-13L4240003 (Ozlem E. Yildirim), and Atilim University Biochemistry Research Laboratory Infrastructure (Belgin S. Isgor, Yasemin G. Isgor).Science Citation Index Expande
Strategies to increase the service life of existing bridge decks
No full textsubmitted by Burkan Isgor, Jason Ideker, David Trejo, Oregon State University ; for Oregon Department of Transportation, Research Unit.Title from PDF title page (viewed on April 10, 2020)."SPR 780."Covers OCLC #1149991467.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Includes bibliographical references.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Effect of Alpha-1-Adrenoceptor Blocker on Cytosolic Enzyme Targets for Potential use in Cancer Chemotherapy
No full textISGOR, Belgin S/0000-0001-5716-3159; Isgor, Yasemin G./0000-0002-6021-257XDoxazosin is one of the quinazoline-based alpha 1-adrenergic receptor antagonists in clinical use for the treatment of hypertension and benign prostate hyperplasia. Doxazosin-induced cytotoxicity studies, resulted in growth inhibition and apoptosis, show its potential therapeutic benefits for several forms of cancers. These effects on cells occur as adrenoceptor-independent mechanisms, as observed with other quinazoline family of alpha-1 blockers. Moreover, Doxazosin induced apoptosis is associated with pathways, including EGFR, NF-kappa beta and TGF-beta signaling which typically engage Src as a central signaling component. Recent evidences show that glutathione transferases, may also contribute to these signaling events, through the kinases that share signaling pathways with Src, responsible for the regulation of transferase activity. In addition, the overactive glutathione transferases are related with anticancer drug resistance, as well as cancer development. Therefore, in the present study, the anticancer potential of Doxazosin was investigated by in vitro enzyme assays that were used to develop full dose-response profiles of drug at varying doses. The drug dose that exerts 50% inhibition of enzyme activity is defined as IC50 value and determined through the nonlinear regression analysis of dose-response data. The IC50 values determined for Src kinase, total protein tyrosine kinase, cytosolic total Src family kinase and total glutathione transferase enzymes were within nanomolar to low micromolar range. These results suggest that Doxazosin may be used to improve multifunctional therapeutic formulations to provide reduced drug resistance and enhanced cytotoxicity at target tissues
Synthesis and Biological Study of Novel Indole-3 Derivatives as Src Kinase and Glutathione S-Transferase Inhibitors
No full textIsgor, belgin S/0000-0001-5716-3159; Isgor, Yasemin G./0000-0002-6021-257XThe aim of this study is to design and synthesize novel dual inhibitors of Src protein tyrosine kinase (PTK) and Glutathione S-transferases (GSTs), as a potential drug lead with therapeutic efficacy on cancer and immune disorders. The biological activity profiling of small molecule inhibitors via miniaturized biochemical techniques compatible with medium throughput screening and focused screening methodologies were performed. To determining the effects of small molecule inhibitors on Src kinase and Phase II detoxification enzyme GST isozymes in liver homogenates used to verify their roles in drug resistance mechanism for cancer chemotherapeutics. In this study, 14 indole-3-imine-2-on and N-benzyl indole-3-imine-2-on derivatives were synthesized for dual activities against Src and GST. The chemical structures and purities of compounds were verified by IR, H-1 NMR, MASS spectroscopy, and elemental analysis. The compounds 2, 3 and 9 are found slightly active against both enzyme Src and GST.Ankara University Scientific Research Funds [BAP 09B3336002]This project is received a funding support from Ankara University (BAP 09B3336002) Scientific Research Funds.Science Citation Index Expande
Isoscalar Giant Octupole Resonance ISGOR of 116Cd using Self-Consistent Skyrme QRPA
No full textCollective models based on the random phase approximation (RPA) are widely used to accurately depict collective modes of response. They can quickly calculate the strength function for the entire nuclear mass range. The quasi-particle random phase approximation (QRPA), which considers the pairing effect, is an enhanced RPA model. It is anticipated that this effect will be significant for open-shell nuclei. In this work, the self-consistent Skyrme Hartree-Fock-Bardeen, Cooper, and Schrieffer (HF-BCS) and QRPA models have been used to study the isoscalar giant octupole resonance (ISGOR) in the 116Cd isotope. Ten Skyrme-type parameters are utilized in the computations since they may be identified by different values of the incompressibility modulus KMN in nuclear matter. The calculated strength distributions and centroid energy are compared with available experimental data. We saw that the strength distributions varied depending on the type of Skyrme-interaction, and we also observed a definite impact of the KNM values on the centroid energy
Evaluation of Perylenediimide Derivatives for Potential Therapeutic Benefits on Cancer Chemotherapy
No full textISGOR, Belgin S/0000-0001-5716-3159; Isgor, Yasemin G./0000-0002-6021-257XPerylene derivatives, known to have potential therapeutic benefits on particular cancer types as photosensitizers, may also function as small-molecule inhibitors with promising therapeutic value for diverse diseases. This recently recognized biological activity was attributed to their capacity to modulate the function of various enzymes as biological targets in vitro. Although the inhibitory activity on glutathione transferase and Src tyrosine kinase is important in determining the anticancer potential of compounds for target-specific drug design and development, to date, there are no successful inhibitors of this kind. Moreover, there are only a few studies about the effects of perylene derivatives on glutathione transferase and various kinases. In this study, four novel perylene compounds, N,N'-disubstituted perylenediimides and their 1,7-dibromo derivatives, were synthesized and evaluated for their biological activities. Here, among the compounds analyzed, one of them was identified with strong glutathione transferase inhibition and two with dual activity for both glutathione transferase and c-src inhibition. These results revealed that perylene derivatives may be employed as potential chemosensitizers to prevent chemotherapy-dependent drug resistance and identified as prospective anticancer agents with dual activity on both glutathione transferase and c-src enzymes.Atilim University; Balikesir University [BAP2009/40, BAP 2010/18]; Scientific and Technological Research Council of Turkey [TUBITAK-110T026]; Undersecretariat of State Planning Organization [DPT-2005-K-120-170]This work was partially supported by grants from the Atilim University (BAP 2011), Balikesir University (BAP2009/40; BAP 2010/18), The Scientific and Technological Research Council of Turkey (TUBITAK-110T026), and Undersecretariat of State Planning Organization (DPT-2005-K-120-170)
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The Pozzolanic Reactivity Test and the Properties of Portland Limestone Cement
No full textThe pozzolanic reactivity test (PRT) is used to quantify the pozzolanic reactivity of supplementary cementitious materials (SCMs). The PRT computes reactivity by measuring heat release (Q) and calcium hydroxide (CH) consumption, as interpreted using thermodynamic modeling. The robustness of PRT is examined by experimentally varying CH-to-SCM ratio, solution-to-solid ratio, sulfate content, alkali type (Na vs. K), and alkali content. Furthermore, the similarities and differences between the PRT and the R3 test (ASTM C1897) are also evaluated. It is shown that the sulfates, as used in the R3 test, did not impact the siliceous reactions; but lead to the preferential formation of monosulfo-aluminates and ettringite with aluminous phases. The inclusion of carbonates, as used in the R3 test, also only impacted the aluminous reactions by forming hemi/mono carbo-aluminates over pozzolanic reaction products. Unlike PRT, the phase assemblage of the reacted products in the R3 test are not consistent and vary depending on the alumina content in the SCM. The PRT is recommended as robust tool to measure the degree of pozzolanic reactivity (DOR*) of the SCMs. A generalized relationship for the DOR* is also developed as a function of Q and CH consumption.
This thesis also examines the performance of cementitious systems made of the clinker of typical sulphate resistant Type II/V cements (which have low aluminate content), LS, and SCMs. The work compares the heat of hydration, shrinkage, mechanical, electrical and transport performance of the paste and mortar made using OPC with the paste and mortar made using portland limestone cement (PLC) and OPC+LS cement with and without typical commercial SCMs (silica fume (SF), fly ash (FA), and slag (SL)).
The heat of hydration, drying shrinkage, and flexural strength were investigated. When compared with OPC, the PLC and OPC+LS did not substantially affect either the extent of reaction at 7 days or the drying shrinkage. However, the degree of hydration of PLC and OPC+LS paste mixtures containing slag were approximately 10% higher than OPC paste mixtures containing slag at the age of 7 days. On the other hand, at early ages (less than 14 days) in the systems that did not contain SL or SF (i.e., plain and FA-containing systems), the flexural strength of the PLC and OPC+LS mortars are 15% and 20% lower than flexural strength of OPC mortars, respectively. The flexural strength was 7% greater at early ages for PLC and OPC+LS samples when combined with SL compared to corresponding OPC samples. The flexural strengths at later ages were similar for all mixtures.
The porosity, formation factor, and pore connectivity of mortars were also examined. The porosity of both PLC and OPC+LS mortars were 4% higher than the porosity of OPC mortar due in part to the dilution of reactive clinker. The effect of dilution was offset with increased clinker reaction. The porosity of PLC+SCM and OPC+LS+SCM mortars was also 2% to 6% higher than the porosity of OPC+ SCM mortars. The mixtures containing SCMs with reactive alumina showed less of an increase in porosity since the limestone reacted to form carbo-aluminate reaction products. Despite the increase in porosity, there was no statistically significant difference between the formation factor of the PLC, OPC+LS, and OPC mortars without SCM. The PLC+SCM, OPC+LS+SCM, and OPC+SCM mortars had a higher formation factor than the plain OPC/PLC/OPC+LS mortars due to pore refinement. Pore refinement was also observed in PLC and OPC+LS mortars containing SCMs with reactive alumina.
The results of this thesis indicate that PLCs (ASTM C595) can be used as a direct replacement for OPCs (ASTM C150) without any significant impact to hydration, shrinkage, mechanical, and transport related performance. PLCs are specifically recommended over OPCs when aluminous SCMs are incorporated in the system
Cellular Defense Enzyme Profile for Non-Cytotoxic and Phenol Enriched Extracts of <i>heliotropium Europaeum</I>, <i>carlina Oligocephala</I> and <i>echinops Ritro</I>
No full textISGOR, Belgin S/0000-0001-5716-3159; Isgor, Yasemin G./0000-0002-6021-257XBackground and Objective:The discovery of traditional plants with some medicinal properties, verifying their biological targets and the bioassay guided standardization of their active components are the particular interest of diverse research groups recently. These efforts may help to revise the therapy modalities with natural product supplements. In this context, the possible biological targets of plants, namely Heliotropium europaeum, Carlina oligocephala and Echinops ritro, with no known medicinal value but recognized for their region specific traditional use, were evaluated. Here, the biological targets were enzymes of the antioxidant and xenobiotic defense mechanisms, with roles on inflammatory response. Materials and Methods: Cytotoxicity analyses were performed by using human promyelocytic (HL60) and chronic myelogenous leukemia (K562) cells for circulating models and breastadenocarcinoma (MCF7) cells for epithelial model to evaluate the non-toxic dose range of extracts by virtue of XTT and trypan blue. The target aimed effectiveness of these plants were determined with dose response profiles and IC50 values against glutathione peroxidase (GPX), glutathione transferase(GST),catalase (CAT) and superoxide dismutase (SOD) targets, as well as their capacity to reduce free radicals (DPPH) and non-radical hydrogen peroxide (H2O2). For standardization purposes, all extract concentrations were brought to 23.81 mg L-1 GAE and dilutions were made from these stocks. The IC50 values were determined by nonlinear regression analysis, with sigmoidal dose-response 4-parameter logistic equation. Results: The results showed that the best DPPH and H2O2 scavenging was observed with E ritro extracts. On the contrary, the best enzyme inhibition profile was observed with H europaeum against CAT, SOD, GPX and GST targets. Among the enzymes evaluated, all plants with different fractions also exerted strong GPX and CAT inhibition. Conclusion: The enzyme profiling of extracts may reveal the medicinal value of herbal remedies, by identifying their effects on cellular targets. In addition to define how reasonable the use of plants in traditional and complementary medicine (TCM) practices,these efforts may help to improve the standardized supplement preparations to benefit therapeutics with reduced efficiency due to inference with cellular defense and drug resistance enzymes, or both.Atilim University Research grant [BAP-A-1112-02]; [TUBITAK-COST-109T548-2010]This study was performed at Atilim University Biochemistry Research Laboratory, partially funded by TUBITAK-COST-109T548-2010, Atilim University Research grant BAP-A-1112-02. Authors would like to thank Karl Machin for lingual
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A Dataset on the influence of air voids and fluid absorption on salt-induced calcium oxychloride damage
No full textThis dataset aims to display damage induced by calcium oxychloride formation with respect to concrete air void content, and boundary conditions. The purpose of this data set is to complete the data in the paper submitted to Cement and Concrete Composites Journal.
The citation for this journal paper is : [1] Rita M. Ghantous, K. Zetterberg, H. H. Becker, A. Behravan, M. T. Ley, O. B. Isgor, W. J. Weiss (2022). “The influence of air voids and fluid absorption on salt-induced calcium oxychloride damage,” submitted to Cement and Concrete Composites Journal.Keywords: deicing salts, calcium chloride, calcium oxychloride, salt damage, air void content, concrete pavement
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