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Almessiere MA, Güner S, Slimani Y, Korkmaz AD, Baykal A. Effect of Mo substitution on structure, morphology and magnetic features of Sr0.8Ni0.2Fe12−2xMoxO19 (x ≤ 0.35) hexaferrites. Chem Pap 2022. [DOI: 10.1007/s11696-022-02527-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ozdede A, Güner S, Ozcifci G, Yurttas B, Toker Dincer Z, Atli Z, Uygunoglu U, Durmaz E, Ucar D, Ugurlu S, Saip S, Tabak ÖF, Hamuryudan V, Seyahi E. POS1255 SAFETY OF THE PFIZER/BIONTECH AND SINOVAC/CORONAVAC VACCINES AMONG PATIENTS WITH BEHCET’S SYNDROME AND FAMILIAL MEDITERRANEAN FEVER. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.3711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BackgroundSince first emerged in December 2019, the COVID-19 pandemic has resulted in a death toll surpassing 5.5 million worldwide and had severe consequences on the global economy, environment, public health and social life [1, 2]. Multiple potential vaccines against COVID-19 have been developed swiftly and as shown in several phase 3 clinical trials, they demonstrated considerable efficacy without an unusual safety signal in healthy individuals.ObjectivesIn this study, we aimed to evaluate vaccine reactivity and disease flare following vaccination with either Sinovac/CoronaVac or Pfizer/BioNTech among BS and FMF patients compared with patients with various diagnosis of RD and healthy controls.MethodsOnly those patients and healthy controls who rece,ved at least one single shot of either CoronoVac or BioNTech against COVID-19 were included in the study. We tried to contact all of these patients and controls consecutively by telephone and attempted to make interviews with the eligible ones.ResultsWe studied the efficacy, side effects and disease flares after COVID-19 vaccination in 256 patients with Behcet’s syndrome (BS), 247 with familial Mediterranean fever (FMF), 601 with rheumatic diseases (RD) and 612 healthy controls (HC). Study participants were vaccinated either with CoronaVac (BS:109, FMF: 90, RD: 343, and HC: 334) or BioNTech (BS: 147, FMF:157, RD: 258 and HC: 278). BioNTech ensured a significantly better efficacy than CoronaVac against COVID-19 in all patient groups (BS: 1.4% vs 10.1%; FMF: 3.2% vs 12.2%, RD:2.7% vs 6.4%). Those with at least one adverse event (AE) were significantly more frequent among those vaccinated with BioNTech than those with CoronaVac (BS: 86.4% vs 45%; FMF: 83.4% vs 53.3%; RD: 83.3% vs 45.5% and HC: 86.3% vs 52.1%). The majority of AEs were mild to moderate and transient and this was true for either vaccine. There were also AEs that required medical attention in all study groups following CoronaVac (BS:5.5%, FMF:3.3%, RD:2.9% and HC:3.3%) or BioNTech (BS:5.4%, FMF:1.9%, RD:4.7% and HC:4.7%). The main causes for medical assistance were disease flare, and cardiovascular events. Disease flares after vaccination were significantly more frequent among BS (41/256; 16.0%) and FMF (43/247; 17.4%) patients compared to patients with RD (36/601; 6.0%). This was true for both CoronaVac (BS: 11.0%, FMF: 24.4% and RD: 5.2%, p<0.001) and BioNTech (BS: 19.7%, FMF: 13.4% and RD: 7.0%, p=0.001)(Table 1).Table 1.Flares among patients with Behçet’s syndrome, familial Mediterranean fever, rheumatic diseases after vaccination with CoronaVac and BioNTechCoronaVacBehçet’s syndrome,n=109Familial Mediterranean Fever,n=90Rheumatic diseases, n=343Flares, n (%)Flares, n (%)Flares, n (%)12 (11.0)22 (24.4)18 (5.2)BioNTechBehçet’s syndrome, n=147Familial Mediterranean Fever, n=157Rheumatic diseases, n=258Flares, n (%)Flares, n (%)Flares, n (%)29 (19.7)21 (13.4)18 (7.0)RA, Rheumatoid Arthritis; BS, Behçet’s syndrome; FMF, Familial Mediterranean FeverConclusionOur study demonstrates that BS and FMF patients vaccinated with either CoronaVac or BioNTech demonstrated almost similar AE profile and frequency compared to RD patients and HC. AEs that required physician consultation or hospitalization occurred in all study groups after either CoronaVac or BioNTech. Caution should be required when monitoring these patients after vaccination. Increased frequency of flares in BS and FMF compared to that seen in RD might reflect defects in innate immunity and deserves further investigation.References[1]https://covid19.who.int Accessed date 22.01.2022[2]Nicola M, Alsafi Z, Sohrabi C, Kerwan A, Al-Jabir A, Iosifidis C, Agha M, Agha R. The so-cio- economic implications of the coronavirus pandemic (COVID-19): A review. Int J Surg. 2020 Jun; 78:185-193. doi: 10.1016/j.ijsu.2020.04.018. PMID: 32305533; PMCID: PMC7162753.Disclosure of InterestsAyse Ozdede: None declared, Sabriye Güner: None declared, Guzin Ozcifci: None declared, Berna Yurttas: None declared, Zeynep Toker Dincer: None declared, Zeynep Atli: None declared, Ugur Uygunoglu: None declared, Eser Durmaz: None declared, Didar Ucar: None declared, Serdal Ugurlu Speakers bureau: Novartis,Pfizer,Celltrion and Lilly, Sebahattin Saip: None declared, Ömer Fehmi Tabak Speakers bureau: Abbvie, Gilead, MSD and GSK, Consultant of: Abbvie, Gilead, MSD and GSK, Vedat Hamuryudan: None declared, Emire Seyahi Speakers bureau: Pfizer, Abbvie, Novartis and Gilead,
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Almessiere M, Güner S, Slimani Y, Baykal A, Shirsath SE, Korkmaz AD, Badar R, Manikandan A. Investigation on the structural, optical, and magnetic features of Dy3+ and Y3+ co-doped Mn0.5Zn0.5Fe2O4 spinel ferrite nanoparticles. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131412] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Almessiere MA, Güner S, Gungunes H, Sertkol M, Slimani Y, Badar R, Akhtar S, Shirsath SE, Baykal A. Structural, Magnetic, and Mossbauer Parameters' Evaluation of Sonochemically Synthesized Rare Earth Er 3+ and Y 3+ Ions-Substituted Manganese-Zinc Nanospinel Ferrites. ACS Omega 2021; 6:22429-22438. [PMID: 34497932 PMCID: PMC8412957 DOI: 10.1021/acsomega.1c03416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/12/2021] [Indexed: 05/16/2023]
Abstract
The effect of Er3+ and Y3+ ion-co-substituted Mn0.5Zn0.5Er x Y x Fe2-2x O4 (MZErYF) (x ≤ 0.10) spinel nanoferrites (SNFs) prepared by a sonochemical approach was investigated. Surface and phase analyses were carried out using SEM, TEM, and XRD. Hyperfine parameters were determined by fitting room-temperature (RT) Mossbauer spectra. Magnetic field-dependent magnetization data unveiled the superparamagnetic nature at RT and ferrimagnetic nature at 10 K. RT saturation magnetization (M S) and calculated magnetic moments (n B) are 34.84 emu/g and 1.47 μB, respectively, and have indirect proportionalities with increasing ion content. M S and n B data have a similar trend at 10 K including remanent magnetizations (M r). The measured coercivities (H C) are between 250 and 415 Oe. The calculated squareness ratios are in the range of 0.152-0.321 for NPs and assign the multidomain nature for NPs at 10 K. The extracted effective magnetocrystalline constants (K eff) have an order of 104 erg/g except for Mn0.5Zn0.5Er0.10Y0.10Fe1.80O4 SNFs that has 3.37 × 105 erg/g. This sample exhibits the greatest magnetic hardness with the largest magnitude of H C = 415 Oe and an internal anisotropy field H a = 1288 Oe among all magnetically soft NPs.
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Affiliation(s)
- Munirah A. Almessiere
- Department
of Physics, College of Science, Imam Abdulrahman
Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
- Department
of Biophysics, Institute for Research and Medical Consultation (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
| | - Sadik Güner
- Institute
of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany
| | - Hakan Gungunes
- Department
of Physics, Hitit University, Çevre Yolu Bulvarı, 19030 Çorum, Turkey
| | - Murat Sertkol
- Department
of Basic Science, Deanship of Preparatory Year and Supporting Studies, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 34212, Saudi Arabia
| | - Yassine Slimani
- Department
of Biophysics, Institute for Research and Medical Consultation (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
| | - Rabail Badar
- Université
Toulouse III - Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse CEDEX 9, France
| | - Sultan Akhtar
- Department
of Biophysics, Institute for Research and Medical Consultation (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
| | - Sagar E. Shirsath
- School
of Materials Science and Engineering, University
of New South Wales, Kensington, Sydney, New South Wales 2052, Australia
| | - Abdulhadi Baykal
- Department
of Nanomedicine Research, Institute for Research and Medical Consultation
(IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
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Slimani Y, Algarou N, Almessiere M, Sadaqat A, Vakhitov M, Klygach D, Tishkevich D, Trukhanov A, Güner S, Hakeem A, Auwal I, Baykal A, Manikandan A, Ercan I. Fabrication of exchange coupled hard/soft magnetic nanocomposites: Correlation between composition, magnetic, optical and microwave properties. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2021.102992] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Almessiere M, Slimani Y, Rehman S, Khan F, Güngüneş Ç, Güner S, Shirsath SE, Baykal A. Magnetic properties, anticancer and antibacterial effectiveness of sonochemically produced Ce3+/Dy3+ co-activated Mn-Zn nanospinel ferrites. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2020.08.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Almessiere MA, Slimani Y, Demir Korkmaz A, Güner S, Baykal A, Shirsath SE, Ercan I, Kögerler P. Sonochemical synthesis of Dy 3+ substituted Mn 0.5Zn 0.5Fe 2-xO 4 nanoparticles: Structural, magnetic and optical characterizations. Ultrason Sonochem 2020; 61:104836. [PMID: 31683234 DOI: 10.1016/j.ultsonch.2019.104836] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/11/2019] [Accepted: 10/21/2019] [Indexed: 05/27/2023]
Abstract
Mn0.5Zn0.5DyxFe2-xO4 (x ≤ 0.03) nanoparticles (NPs) were fabricated by using Ultrasonic irradiation using UZ SONOPULS HD 2070 ultrasonic homogenizer (frequency of 20 kHz and power of 70 W). Structural and morphological analyses were performed via XRD (X-ray powder diffractometer), TEM (Transmission electron microscopy) and SEM (Scanning electron microscopy). XRD presented the formation of Mn-Zn ferrite with average crystal size in 11 to 18 nm range. Direct optical energy band gaps (Eg) were specified applying diffuse reflectance investigations. Eg values are in a small band range of 1.61-1.67 eV. Low (10 K) and room temperature VSM data were recorded applying ±90 kOe external magnetic field. All samples exhibit superparamagnetic properties at RT. Magnetization parameters significantly increase due to coordination of Dy3+ rare earth ions. Magnetic moment per molecule (nB) increases from 0.952 μB to 1.137 μB and from 2.312 μB to 2.547 μB at RT and at 10 K data respectively. 10 K coercivity (Hc) values decrease from 260 Oe to 43 Oe. All samples have squareness ratios (SQR) of 0.231-0.400 range assigning the multi-domain structure at 10 K. ZFC-FC magnetization curves that were registered for two selected samples exhibit a divergence and a sharp drop below their Tpeak positions. This event is typically correlated to the collective freezing of system and spin-glass-like phase. Real part AC susceptibility data slightly shift toward high temperature regions with increasing frequencies. Critical Slowing Down (CSD) model explained the spin dynamics of interacting NPs consistently with literature and proved the spin-glass behavior of samples at low temperatures.
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Affiliation(s)
- M A Almessiere
- Department of Biophysics, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia; Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia
| | - Y Slimani
- Department of Biophysics, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia.
| | - A Demir Korkmaz
- Department of Chemistry, Istanbul Medeniyet University, 34700 Uskudar-Istanbul, Turkey
| | - S Güner
- Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany
| | - A Baykal
- Department of Nano-Medicine Research, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia
| | - S E Shirsath
- School of Materials Science and Engineering, University of New South Wales, Kensington, Sydney, NSW 2052, Australia
| | - I Ercan
- Department of Biophysics, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia
| | - P Kögerler
- Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany
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Slimani Y, Almessiere MA, Güner S, Kurtan U, Baykal A. Impacts of Sol-Gel Auto-Combustion and Ultrasonication Approaches on Structural, Magnetic, and Optical Properties of Sm-Tm co-Substituted Sr 0.5Ba 0.5Fe 12O 19 Nanohexaferrites: Comparative study. Nanomaterials (Basel) 2020; 10:E272. [PMID: 32041171 PMCID: PMC7075209 DOI: 10.3390/nano10020272] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 11/20/2022]
Abstract
In this paper, we introduced a comparative study of Sm-Tm-substituted Sr-Ba nanohexaferrites (NHFs), Sr0.5Ba0.5TmxSmxFe12-2xO19 with x = 0.00-0.05, manufactured via both citrate sol-gel auto-combustion and ultrasonication approaches. The phase formation of M-type hexaferrite (HF) for both compositions was confirmed by X-ray diffraction (XRD) powder pattern, Fourier-transform infrared (FT-IR) spectra, scanning and transmission electron microscopy (SEM and TEM) micrographs, energy dispersive X-ray (EDX) spectra, and elemental mappings. The magnetic properties at room temperature (RT) and low temperature (T = 10 K) were also investigated. M-H loops revealed ferrimagnetic nature for various prepared nanohexaferrites via sol-gel and ultrasonication routes. The Ms (saturation magnetization) and Mr (remanence) values increased with increasing Tm-Sm substituting contents. Ms and Mr reached their maximum values at x = 0.04 in the case of samples prepared using the sol-gel technique and at x = 0.03 for those prepared via ultrasonication route. M-H loops were very broad in samples prepared via ultrasonication route in comparison to those produced by means of the sol-gel approach, implying that the products synthesized via ultrasonication route have greater values of coercivity (Hc). The variations in Hc values with respect to Tm-Sm substitutions were governed by the evolutions in the magneto-crystalline anisotropy. Diffuse reflectance spectra (DRS) were employed to estimate the direct band gap of pristine and co-substituted Sr0.5Ba0.5Fe12O19 hexaferrites. Optical energy band gaps (Eg) of pristine samples were significantly tuned by co-substitution of Tm3+ and Sm3+ ions. Eg values of the Sr0.5Ba0.5Fe12O19 sample, which was synthesized using the sol-gel method, decreased almost linearly from 1.75 to 1.45 eV by increasing co-doped ion content. However, we observed a sharp drop from 1.85 eV to an average of 1.50 eV for the samples, which were synthesized using the ultrasonication approach.
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Affiliation(s)
- Yassine Slimani
- Department of Biophysics, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Munirah Abdullah Almessiere
- Department of Biophysics, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Sadik Güner
- Institute of Inorganic Chemistry, RWTH Aachen University, D-52074 Aachen, Germany
| | - Umran Kurtan
- Department of Materials and Materials Processing Technologies, Vocational School of Technical Sciences, İstanbul University-Cerrahpaşa, 34500 İstanbul, Turkey
| | - Abdulhadi Baykal
- Department of Nanomedicine, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
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Almessiere MA, Slimani Y, Korkmaz AD, Baykal A, Güngüneş H, Sözeri H, Shirsath SE, Güner S, Akhtar S, Manikandan A. Impact of La3+ and Y3+ ion substitutions on structural, magnetic and microwave properties of Ni0.3Cu0.3Zn0.4Fe2O4 nanospinel ferrites synthesized via sonochemical route. RSC Adv 2019; 9:30671-30684. [PMID: 35529361 PMCID: PMC9072207 DOI: 10.1039/c9ra06353f] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/19/2019] [Indexed: 01/12/2023] Open
Abstract
In the current study, Ni0.4Cu0.2Zn0.4LaxYxFe2−xO4 (x = 0.00 − 0.10) nanospinel ferrites (NSFs) were fabricated via an ultrasonic irradiation route. The creation of single phase of spinel nanoferrites (NSFs) was investigated by X-ray powder diffractometry (XRD) and selected area diffraction pattern (SAED). The cubic morphology of all samples was confirmed by scanning and transmission electron microscopies (SEM and TEM) respectively. The UV-Vis investigations provided the direct optical energy band gap values in a narrow photon energy interval of 1.87–1.92 eV. The 57Fe Mössbauer spectroscopy analysis explained that the hyperfine magnetic fields of Octahedral (Oh) and Tetrahedral (Td) sites decreased with substitution. The paramagnetic properties of NPs decrease with increase of content of doped ions. Investigations of magnetic properties reveal a superparamagnetic nature at 300 K and soft ferromagnetic trait at 10 K. The Ms (saturation magnetization) and Mr (remanence) decrease and the Hc (coercivity) increases slightly with La3+ and Y3+ substitution. The observed magnetic traits are deeply discussed in relation with the morphology, structure, magnetic moments and cation distributions. The microwave characterization of the prepared NSFs showed that, dissipation (i.e., absorption) of incoming microwave energy occurs at a single frequency, for each sample, lying between 7 and 10.5 GHz. The reflection losses (RL) at these frequencies range from −30 to −40 dB and the mechanism of which is explained in the framework of dipolar relaxation and spin rotation. The best microwave properties were obtained with a LaY concentration of x = 0.08 having an RL of −40 dB @ 10.5 GHz and an absorption bandwidth of 8.4 GHz @ −10 dB. With these high values of RL and absorbing bandwidth, LaY doped NiCuZn NSF products would be promising candidates for radar absorbing materials in the X-band. The best microwave properties for the NSFs were obtained with an LaY concentration of x = 0.08, RL of −40 dB @ 10.5 GHz and absorption bandwidth of 8.4 GHz @ −10 dB. The NSF products show promise as radar absorbing materials in the X-band.![]()
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Affiliation(s)
- M. A. Almessiere
- Department of Biophysics
- Institute for Research & Medical Consultations (IRMC)
- Imam Abdulrahman Bin Faisal University
- Dammam
- Saudi Arabia
| | - Y. Slimani
- Department of Biophysics
- Institute for Research & Medical Consultations (IRMC)
- Imam Abdulrahman Bin Faisal University
- Dammam
- Saudi Arabia
| | - A. Demir Korkmaz
- Department of Chemistry
- Istanbul Medeniyet University
- Istanbul
- Turkey
| | - A. Baykal
- Department of Nanomedicine
- Institute for Research & Medical Consultations (IRMC)
- Imam Abdulrahman Bin Faisal University
- Dammam
- Saudi Arabia
| | - H. Güngüneş
- Department of Physics
- Hitit University
- Çorum
- Turkey
| | - H. Sözeri
- TUBITAK-UME
- National Metrology Institute
- Turkey
| | - Sagar E. Shirsath
- School of Materials Science and Engineering
- University of New South Wales
- Sydney
- Australia
| | - S. Güner
- Institute of Inorganic Chemistry
- RWTH Aachen University
- D-52074 Aachen
- Germany
| | - S. Akhtar
- Department of Biophysics
- Institute for Research & Medical Consultations (IRMC)
- Imam Abdulrahman Bin Faisal University
- Dammam
- Saudi Arabia
| | - A. Manikandan
- Department of Chemistry
- Bharath Institute of Higher Education and Research (BIHER)
- Bharath University
- Chennai
- India
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Asiri S, Amir M, Güner S, Gungunes H, Batoo KM, Sertkol M, Imran A, Baykal A. Structural, Optical and Mössbauer Study of Ba1 − xCuxFe12O19 (0.5 ≤ x) Nano Hexaferrites. J Inorg Organomet Polym Mater 2018. [DOI: 10.1007/s10904-018-0794-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Asiri S, Güner S, Demir A, Yildiz A, Manikandan A, Baykal A. Synthesis and Magnetic Characterization of Cu Substituted Barium Hexaferrites. J Inorg Organomet Polym Mater 2017. [DOI: 10.1007/s10904-017-0735-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kumru M, Bardakçı T, Güner S. DFT calculations and experimental FT-IR, dispersive-Raman and EPR spectral studies of Copper (II) chloride complex with 3-amino-1-methylbenzene. Spectrochim Acta A Mol Biomol Spectrosc 2014; 123:187-193. [PMID: 24394534 DOI: 10.1016/j.saa.2013.12.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/09/2013] [Accepted: 12/11/2013] [Indexed: 06/03/2023]
Abstract
In this study, we present the synthesis and the characterization of Copper (II) chloride complex with 3-amino-1-methylbenzene (3A1MB). This complex was characterized by vibrational and EPR spectroscopic techniques and elemental analysis. The molecular structure and spectrometry of this complex: Cu(3A1MB)2Cl2 and its ligand: 3A1MB have been investigated theoretically by performing DFT/B3LYP calculations. Cu(3A1MB)2Cl2 has been optimized as two conformers and the more stable conformer is determined. The optimized geometries and calculated vibrational frequencies have been evaluated via comparison with experimental values, and the normal modes were assigned on the basis of the percent potential energy distribution (PED). A good agreement between calculated and experimental data is observed.
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Affiliation(s)
- Mustafa Kumru
- Department of Physics, Faculty of Arts and Sciences, Fatih University, Istanbul, Turkey
| | - Tayyibe Bardakçı
- Department of Physics, Faculty of Arts and Sciences, Fatih University, Istanbul, Turkey.
| | - Sadik Güner
- Department of Physics, Faculty of Arts and Sciences, Fatih University, Istanbul, Turkey
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Bardakçı T, Kumru M, Güner S. Molecular structure, vibrational and EPR spectra of Cu(II) chloride complex of 4-amino-1-methylbenzene combined with quantum chemical calculations. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.09.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Arıkan E, Güner S. The Impact of Corporate Social Responsibility, Service Quality and Customer-company Identification on Customers. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.sbspro.2013.10.498] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
A metal-free phthalocyanine with four pyridyl donor groups, bound through ethylthio ester bridges on the periphery, have been prepared. The pyridine donors were quaternized with iodomethane to a water-soluble tetracationic phthalocyanine. The tetranuclear supramolecular phthalocyanine was prepared by the coordination of peripheral pyridine donors with VO(acac)2. The paramagnetic tetranuclear structure was studied in powder and solution forms by the electron paramagnetic resonance (EPR) technique. Electron paramagnetic resonance studies, together with the other spectral data confirmed the presence of identical pyridine-coordinated VO(acac)2 paramagnetic centers attached to the peripheral positions of the phthalocyanine core. The X-band EPR signals recorded from powder and solution forms of supramolecules have a characteristic line shape that proves the presence of axial symmetry around the paramagnetic vanadium ions. The anisotropic Lande splitting factors were calculated as g ∥ < g ⊥ < g e = 2.0023. Orbital energy levels for magnetic electrons were determined from theoretically fitted Spin Hamiltonian parameters.
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Affiliation(s)
- Ibrahim Özçesmeci
- Department of Chemistry, Technical University of Istanbul, Maslak, Istanbul 34469, Turkey
| | - Sadik Güner
- Department of Physics, Fatih University, Buyukcekmece, İstanbul, 34500, Turkey
| | - Ali Ihsan Okur
- Department of Chemistry, Technical University of Istanbul, Maslak, Istanbul 34469, Turkey
| | - Ahmet Gül
- Department of Chemistry, Technical University of Istanbul, Maslak, Istanbul 34469, Turkey
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Affiliation(s)
- Ramazan Öztürk
- b Department of Chemistry , Fatih University , 34500, Buyukcekmece, Istanbul, Turkey
| | - Sadik Güner
- c Department of Physics , Fatih University , 34500, Buyukcekmece, Istanbul, Turkey
| | - Bekir Aktaş
- d Department of Physics , Gebze Institute of Technology , 41400, Gebze, Kocaeli, Turkey
| | - Ahmet Gül
- a Department of Chemistry , Technical University of Istanbul , 34469, Maslak, Turkey
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Affiliation(s)
- Ramazan Öztürk
- a Department of Chemistry , Fatih University , 34900, Buyukcekmece, Istanbul, Turkey
| | - Sadik Güner
- b Department of Physics , Fatih University , 34900, Buyukcekmece, Istanbul, Turkey
| | - Bekir Aktas
- c Gebze Institute of Technology , Gebze, Turkey
| | - Ahmet Gül
- d Department of Chemistry , Technical University of Istanbul , 80626, Maslak, Istanbul, Turkey
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Demirci T, Köseoğlu Y, Güner S, Ülküseven B. Oxovanadium(IV) complexes of bromo-and methoxy substituted N1,N4-diarylidene-S-methylthiosemicarbazones. OPEN CHEM 2006. [DOI: 10.1007/s11532-005-0011-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
AbstractFour new oxovanadium(IV) compounds were prepared by template reaction of salicyl-, 5-bromosalicyl-and 3-methoxysalicyl-aldehyde S-methylthiosemicarbazones with 2-hydroxy-, 5-bromo-2-hydroxy-and 3-methoxy-2-hydroxy-benzaldehyde in various combinations. The compounds were isolated as stable solid compounds with general formula [VO(L)] and characterized by elemental analysis, conductivity and magnetic measurements, electronic, IR and EPR spectroscopy. The X-band EPR signals recorded from powder forms of all samples have a single asymmetric line shape and theoretical fit studies proved the presence of axial symmetry around the paramagnetic vanadium ions. The anisotropic Lande splitting factors take values of g‖ < g⊥ < ge = 2.0023. Orbital energy levels for magnetic electrons were determined from theoretically well fitted Spin Hamiltonian parameters. The EPR spectra recorded from solution forms almost have isotropic character.
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Affiliation(s)
- Tülay. Demirci
- 1Department of Chemistry, Istanbul University, 34320, Avcilar Istanbul, Turkey
| | - Yüksel Köseoğlu
- 2Department of Physics, Fatih University, 34500, Buyukcekmece Istanbul, Turkey
| | - Sadik Güner
- 2Department of Physics, Fatih University, 34500, Buyukcekmece Istanbul, Turkey
| | - Bahri Ülküseven
- 1Department of Chemistry, Istanbul University, 34320, Avcilar Istanbul, Turkey
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Abstract
Single crystals of ZnAl(2)S(4) spinel doped by paramagnetic Cr(3+) and Mn(2+) ions have been studied by the electron paramagnetic resonance (EPR) technique. The crystal field symmetry around the impurity ions has been determined from the angular behaviour of X-band EPR spectra. The anisotropic EPR signal of the Cr(3+) ions shows splitting into 31 narrow lines due to the super-hyperfine interaction between unpaired electron spins of the chromium centres and nuclear spins of six neighbouring Al(27) (I = 5/2) ions. It has been established that the Cr(3+) ions are located at the octahedral sites in the spinel structure, and the super-hyperfine interaction results from a weak covalent bounding with the Al atoms. The EPR signals of the Cr(3+) paramagnetic centres show no fine-structure splitting due to a perfectly cubic symmetry of the local crystal field in the octahedral sites of the ZnAl(2)S(4) spinel structure. A weak EPR signal consisting of six components has been ascribed to the transitions between hyperfine levels of the Mn(2+) (I = 5/2,S = 5/2) ions located at tetrahedral sites, while the fine-structure splitting of each component could be resolved only for special orientations of the sample in the external magnetic field. The parameters of the EPR signal of both chromium and manganese centres indicate that there is an essential covalence in the ZnAl(2)S(4) spinel crystal. Very narrow linewidths (∼2 Oe) of the Cr(3+) EPR signal components point to very high homogeneity and quality of the ZnAl(2)S(4) crystals.
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Affiliation(s)
- S Güner
- Physics Department, Fatih University, 34500 Büyükçekmece-Istanbul, Turkey
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Abstract
Diabetic hearts exhibit decreased responsiveness to stimulation by beta-adrenoreceptor (beta-AR) agonists. This decrease in activity may be due to changes in expression and/or signaling of beta-AR. Recently we showed that right atrial strips from 14-week streptozotocin (STZ)-induced diabetic rat hearts exhibit decreased responsiveness to beta1-AR agonist stimulation, but not to beta2-AR agonist. In the present study, we investigated the effects of long-term diabetes on the expression of cardiac beta1-, beta2-, and beta3-ARs and looked at whether these changes could be restored with insulin treatment. Using reverse transcription-polymerase chain reaction (RT-PCR), PAGE, and Western blot analysis, we found that beta1-AR mRNA and protein levels decreased by 34.9 +/- 5.8 and 44.4 +/- 5.8%, respectively, in 14 week-STZ-treated diabetic rat hearts when compared with age-matched controls. On the other hand, mRNA levels encoding beta2- and beta3-ARs increased by 72.5 +/- 16.6 and 97.3 +/- 26.1%, respectively. Although the latter translated into a proportional increase in beta3-AR protein levels (100.0 +/- 17.0%), beta2-AR protein levels decreased to 82.6 +/- 1.1% of control. Insulin treatment for 2 weeks, after 12 weeks of untreated diabetes, partially restored beta1-AR mRNA and protein levels to 60.1 +/- 8.4 and 83.2 +/- 5.0%, respectively, of control. Although insulin treatment minimally attenuated the rise in mRNA levels encoding beta2- and beta3-ARs, the steady-state levels of these proteins returned to near control values. These data suggest that the decreased responsiveness of diabetic hearts to stimulation of beta-AR agonists may be due to a decrease in beta1-AR and an increase beta3-AR expression.
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Affiliation(s)
- U D Dinçer
- Department of Pharmacology, Faculty of Pharmacy, University of Ankara, Turkey
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22
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Dülger S, Saglam N, Beldüz AO, Güner S, Karaböcek S. DNA cleavage by homo- and heterotetranuclear Cu(II) and Mn(II) complexes with tetrathioether-tetrathiol moiety. Biometals 2000; 13:261-5. [PMID: 11127898 DOI: 10.1023/a:1009222705659] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Novel homotetranuclear Cu(II) and heteronuclear Cu(II)-Mn(II) complexes with tetrathioether-tetrathiol moiety have been prepared and their DNA relaxation activities with plasmid pCYTEXP (5kb) were electrophoretically established. The cleavage products analyzed by neutral agarose gel electrophoresis indicated that the interaction of the metal complexes with supercoiled plasmid DNA yielded linear, nicked or degraded DNA. The relaxation activities of both homo- and heterotetranuclear (SK4) complexes are time- and concentration-dependent. The findings suggest that SK4 with potent nucleolytic activity is a good nuclease substitute in the presence ofcooxidant. Furthermore, the observation of induction of DNA into smaller fragments by SK4 is also significant.
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Affiliation(s)
- S Dülger
- Karadeniz Technical University, Department of Biology, Trabzon, Turkey
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23
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Abstract
The superoxide scavenging activities of copper(II) complexes with the ligands, 6,6'-methylene- bis(5'-amino-3',4'-benzo-2'-thiapentyl)-1,11-diamino- 2,3:9,10-dibenzo-4,8-dithiaundecane (H4L), and 6,6'- bis(5'-amino-3'4'-benzo-2'-thiapentyl)-1,11-diamino- 2,3:9,10-dibenzo-4,8-dithiaundecane (H4L"), were investigated by xanthine-xanthine oxidase (X/XO) assays using nitroblue tetrazolium (NBT) as indicator molecule, and the results were compared with respect to the particular type of anion (ClO4, Cl, NO3) on the apical site of the copper(II) complexes. All of the complexes inhibited the reduction of NBT by superoxide radicals, with the [Cu2(L')](ClO4)2 complex exhibiting the highest scavenging activity against superoxide radicals among the complexes examined. The catalytic efficiency of the complexes for dismutation of superoxide radicals depends on the particular anion liganded to Cu(II) ion in the complexes, and the order of potency was observed to be ClO4 > Cl > NO3 in phosphate buffer at pH 7.40. The Cu(II)-H4L' complexes had the lowest IC50 and catalytic rate constant values indicating that the distorted geometry of the Cu(II)-H4L' complexes influence their catalytic activities for dismutation of superoxide radicals more efficiently. The difference in the activities of the complexes toward superoxide radicals can also be attributed to the nature of the anions on the apical site of the copper(II) complexes and the superoxide dismutase-like activity.
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Affiliation(s)
- S Güner
- Department of Chemistry, Karadeniz Technical University, Trabzon, Turkey
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Ozçelikay AT, Tay A, Güner S, Taşyaran V, Yildizoğlu-Ari N, Dinçer UD, Altan VM. Reversal effects of L-arginine treatment on blood pressure and vascular responsiveness of streptozotocin-diabetic rats. Pharmacol Res 2000; 41:201-9. [PMID: 10623488 DOI: 10.1006/phrs.1999.0576] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we examined the reversal effects of L-arginine (L-ARG) treatment in vivo on blood pressure and on vascular responsiveness of chronic diabetic rats. Twelve weeks after streptozotocin (STZ) injection, the systolic blood pressures (SBP) of diabetic groups have been found to be significantly higher compared with that of control groups. L-ARG treatment for 4 weeks, begun 12 weeks after the onset of diabetes, induced a significant fall in SBP of diabetic rats. Maximal contractile response and sensitivity (pD(2)value) of the aortae to phenylephrine (PE) were significantly enhanced in diabetic rats compared with control subjects. Treatment of diabetic rats with L-ARG completely reversed the increases in responsiveness and sensitivity of aortae to PE. The relaxation response to acetylcholine (ACh), but not to sodium nitroprusside (SNP), in diabetic aorta has been found to be significantly decreased when compared with control subjects. The in vivo treatment with L-ARG reversed the decreased ACh responses to the control level. Plasma malondialdehyde (MDA) level of diabetic rats was also significantly higher than control subjects. However, L-ARG treatment normalized the increase in MDA level of plasma of diabetic rats. All of the effects of L-ARG treatment were found to be specific for diabetic rats but not control subjects. These results show that L-ARG treatment in vivo has a reversal effect on impaired vascular responses and increased oxidative stress. The present findings also suggest that oxidative stress that occurred in diabetes might cause or contribute to the development of hypertension by affecting vascular reactivity. On the other hand, the lipid peroxidation-lowering effect of L-ARG may account for its beneficial effect on SBP and vascular responsiveness of diabetic rats.
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Affiliation(s)
- A T Ozçelikay
- Department of Pharmacology, Faculty of Pharmacy, Ankara University, Tandogan, Ankara, 06100, Turkey
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Konuralp C, Güner S, Cakatay U, Konuralp Z, Yapící N, Maçika H, Aydoğan H, Aykut-Aka S, Alhan C, Gültepe M, Eren EE. Effect of partial oxygen supply on mitochondrial electron transport system during complete cardiac ischemia. J Card Surg 1999; 14:424-34; discussion 435-6. [PMID: 11021367 DOI: 10.1111/j.1540-8191.1999.tb01271.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During complete ischemia we assessed myocardial utilization of the small amount of oxygen available. We also determined whether blood cardioplegia has any advantage over crystalloid cardioplegia in this setting. Patients with preserved left ventricular myocardial function and without anterolateral wall infarct or aneurysm were included to the study. Intermittent cold blood and crystalloid cardioplegia were used in 10 patients (group BC) and 9 patients (group CC), respectively. From myocardial biopsies, obtained before and after ischemia, complete electron transport system (ETS) enzyme activities (NDH, SDH, NCCR, SCCR, and COX) and lactate content were analyzed. Biochemical and hemodynamic analyses also were done. Myocardial and blood temperatures were monitored. Ischemic time was longer in group CC (p < 0.05). There were no important differences in biochemical and hemodynamic variables between the two groups. In addition, there was no difference in NDH and SDH activities as well as COX/SCCR and COX/RS-NCCR ratios between the two groups before and after ischemia. After Ischemia, RS-NCCR in group CC and SCCR and COX activities in both groups were lower than the control. For all enzymes, activity change ratios were not different between groups. Myocardial lactate content was increased in both groups after ischemia. However, the increase in group BC was less (p < 0.01). Based on our findings, we believe that the superiority of blood cardioplegia over crystalloid cardioplegia does not depend on oxygen content, but on other factors such as buffering and free oxygen radical scavenger effects among others. However, with the warm and continuous blood cardioplegia technique, oxygen content might be more important.
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Affiliation(s)
- C Konuralp
- Thoracic and Cardiovascular Surgery Center and Research Hospital, Department of Cardiovascular Surgery, Istanbul, Turkey.
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Abstract
A new selective reagent, S,S'-bis(2-aminophenyl)oxalate (H2L), for the extractive spectrophotometric determination of copper has been prepared. The ligand, H2L, forms a 1:1 complex with copper(II) in methanol. The molar absorptivity of Cu(II)-S,S'-bis(2-aminophenyl)oxalate complex in methanol is 5365 M(-1) cm(-1) at 504 nm. The method has been applied for the determination of copper in pharmaceutical formulations, environmental and foodstuff samples.
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Affiliation(s)
- S Nohut
- Karadeniz Technical University, Department of Chemistry, Trabzon, Turkey
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Güner S, Karaböcek S, Kaklikkaya I. Models for superoxide dismutases: characterization of mononuclear Cu(II), Fe(III), and Mn(II) complexes with 4',5'-bis(salicylideneimino)benzo-15-crown-5. Bioorg Med Chem 1999; 7:329-33. [PMID: 10218825 DOI: 10.1016/s0968-0896(98)00240-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mononuclear Cu(II), Fe(III), and Mn(II) complexes with 4',5'-bis (salicylideneimino)benzo-15-crown-5, (SALH2), were characterized by elemental analysis, IR and UV-Vis spectroscopy and tested spectrometrically as catalysts for superoxide disproportionation by utilizing xanthine-xanthine oxidase (XXO) assays. The results indicate that the examined mononuclear complexes are speculative potent superoxide dismutase mimics.
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Affiliation(s)
- S Güner
- Karadeniz Technical University, Department of Chemistry, Trabzon, Turkey.
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28
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Karaböcek S, Dalman O, Nohut S, Tüfekçi M, Sancak K, Güner S. Determination of relative acidities of some alpha, omega-bis(3-alkyl(aryl)-4,5-dihydro-1H-1,2,4-triazol-5-on-4-yl) alkanes. J Pharm Biomed Anal 1998; 17:375-8. [PMID: 9656146 DOI: 10.1016/s0731-7085(97)00210-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solutions of nine alpha, omega-bis(3-alkyl(aryl)-4,5-dihydro-1H-1,2,4-triazol-5-on-4-yl) alkanes were titrated with tetrabutylammoniumhydroxide (TBAH) in methanol, using potentiometric methods. The half neutralization potentials values were found for all cases. Potentiometric titration curves of compounds in methanol with 0.03 M TBAH are similar to those of weak acids obtained in aqueous media with strong bases. Methanol is found to be a suitable medium for the weakly acidic compounds titrated since they are poorly dissolved in other organic solvents. A comparison among the compounds having the same alkyl chains between the two ring systems has shown that basicity increases and acidity decreases as the size of alkyl chains increases. However, the compound with a substituted phenyl group was found to be the most acidic one among the examined compounds indicating that phenyl group donates ring electrons less effectively to the system. This can be attributed to the stability of the benzene ring.
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Affiliation(s)
- S Karaböcek
- Karadeniz Technical University, Department of Chemistry, Trabzon, Turkey
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29
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Güner S, Colak A, Ozen T, Sentürk HB. Characterization of microsomal aniline hydroxylase of rainbow trout, Salmo gairdneri. Indian J Biochem Biophys 1998; 35:11-5. [PMID: 9699413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Aniline hydroxylase from liver microsomes of rainbow trout Salmo gairdneri converted aniline to p-aminophenol, the specific activity being 0.068 nmoles/min/mg protein in potassium phosphate buffer, pH 7.4 at 25 degrees C. The maximal rate of the enzyme reaction was found at aniline concentrations above 5 mM and in the presence of NADPH. Vmax and K(m) were 0.048 nmoles/min/mg and 0.105 mM respectively. The Hill plot showed the Hill constant to be 1.02 indicating one substrate binding site with no cooperativity. Ca2+ and Mg2+ at concentrations ranging between 1-10 mM stimulated the enzyme activity.
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Affiliation(s)
- S Güner
- Department of Chemistry, Karadeniz Technical University, Trabzon, Turkey
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30
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Ustün G, Güner S, Arer G, Türkay S, Erciyes AT. Enzymatic hydrolysis of anchovy oil: production of glycerides enriched in polyunsaturated fatty acids. Appl Biochem Biotechnol 1997; 68:171-86. [PMID: 9429299 DOI: 10.1007/bf02785989] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In an attempt to produce the polyunsaturated fatty acid (PUFA)-enriched glycerides, commercially available Turkish anchovy oil (PUFA content of 27%), was hydrolyzed with 1,3-specific Rhizomucor miehei lipase. After the hydrolysis, the triglyceride (TG), diglyceride (DG), monoglyceride (MG), and free fatty acid (FFA) composition of the reaction mixture was determined, and fatty acid components of these fractions were analyzed. R. miehei lipase released PUFA extremely slowly, resulting in their accumulation in the TG and DG fractions, especially in TG. The PUFA content in the glyceride mixture (including TG, DG, and MG) increased as hydrolysis progressed. The effects of operational parameters (pH, temperature, time, and enzyme concentration) on the extent of hydrolysis were investigated. Based on these results, optimal reaction conditions were established. At optimal conditions (pH 4.0, 35 degrees C, 3 h, and enzyme concentration of 500 U/g oil), the level of PUFA in the glyceride mixture was raised to 40%. The individual TG and DG fractions contained 45 and 30% PUFA, respectively. Less than 2% of the total PUFA was lost in the FFA fraction.
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Affiliation(s)
- G Ustün
- Istanbul Technical University, Faculty of Chemistry-Metallurgy, Chemical Engineering Department, Turkey
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31
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Yenisey C, Yenice S, Güner G, Güner S. Evaluation of tumor-associated antigens and total sialic acid levels in effusions of malignant and benign origin. Biochem Soc Trans 1996; 24:301S. [PMID: 8736959 DOI: 10.1042/bst024301s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- C Yenisey
- Department of Biochemistry, Adnan Menderes University, Faculty of Medicine, Aydin, Turkey
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Abstract
The ability of trout to metabolize aniline in vitro in the presence of some divalent metal ions was investigated in the liver microsomes of rainbow trout, Salmo gairdneri. Trout liver microsomes were highly capable of catalyzing aniline hydroxylation to p-aminophenol with a specific activity of 0.068 nmoles/ min per mg of microsomal protein in potassium phosphate buffer, pH 7.4 at 25 degrees C. The activity of the aniline hydroxylase system was competitively inhibited by Hg+2, Ni+2, Cd+2, and Zn+2, while Cu+2 and Fe+3 seemed to inhibit the activity noncompetitively at 1 mM aniline concentrations. IC50 values at fixed aniline concentration were estimated to be 0.45 mM for Hg+2, Ni+2, and Cd+2, 1.8 mM for Zn+2 and Fe+3, and 1.3 mM for Cu+2. Eadie-Hofstee plots gave identical Vmax values of approximately 0.046 nmol/min per mg of protein while K(m) values were increased in the presence of Hg+2, Ni+2, Cd+2, and Zn+2, indicating competitive inhibition. Both K(m) and Vmax values were affected by Fe+3 and Cu+2, suggesting noncompetitive inhibition. Ki values extracted from the Dixon plots were determined to be 0.23, 0.43, and 0.65 mM for Hg+2, Ni+2, and Cd+2, respectively, providing the most effective inhibition on the aniline hydroxylase system among studied metal ions. The Ki values were much higher in the presence of others. The results indicate a selective inhibition of the aniline hydroxylase system of trout liver microsomes by divalent metal ions.
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Affiliation(s)
- S Güner
- Department of Chemistry, Karadeniz Technical University, Turkey
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33
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Affiliation(s)
- C Yenisey
- Department of Biochemistry, Adnan Menderes University, Faculty of Medicine, Turkey
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Güner S, Willie A, Millett F, Caffrey MS, Cusanovich MA, Robertson DE, Knaff DB. The interaction between cytochrome c2 and the cytochrome bc1 complex in the photosynthetic purple bacteria Rhodobacter capsulatus and Rhodopseudomonas viridis. Biochemistry 1993; 32:4793-800. [PMID: 8387815 DOI: 10.1021/bi00069a014] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The rates of electron transfer from a ubiquinol analogue to cytochrome c2 catalyzed by the cytochrome bc1 complexes of Rhodobacter capsulatus and Rhodopseudomonas viridis were measured as a function of ionic strength. The effects of ionic strength on the kinetic parameters for the reactions are consistent with a role for electrostatic complex formation between cytochrome c2 and the cytochrome bc1 complex in the electron-transfer pathways in both photosynthetic purple non-sulfur bacteria. Additional support for a docking model in which positively charged lysines on cytochrome c2 interact with negatively charged groups on the Rb. capsulatus cytochrome bc1 complex was obtained from kinetic experiments using Rb. capsulatus cytochrome c2 and equine cytochrome c in which specific lysine residues were altered by site-directed mutagenesis and chemical modification, respectively. Equine cytochrome c, which is a poor electron donor to the reaction center of Rps. viridis, is an effective electron acceptor for the Rps. viridis cytochrome bc1 complex. Chemical modification of lysine residues on Rps. viridis cytochrome c2 has a substantially greater effect on the reduction of the Rps. viridis reaction center by ferrocytochrome c2 than on the oxidation of the Rps. viridis cytochrome bc1 complex by ferricytochrome c2. These data suggest that the docking site for Rps. viridis cytochrome c2 on the Rps. viridis reaction center tetraheme subunit differs in structure from the docking site for the cytochrome on the Rps. viridis cytochrome bc1 complex to a significant extent. In this respect, Rps. viridis differs from photosynthetic purple non-sulfur bacteria in which the reaction center does not contain a tetraheme subunit, where the binding sites for cytochrome c2 on the reaction center and the cytochrome bc1 complex appear to be quite similar.
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Affiliation(s)
- S Güner
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409
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Chankor S, Moomau C, Güner S, Hsu J, Tokito MK, Daldal F, Knaff DB, Harman JG. Characterization of the pet operon of Rhodospirillum rubrum. Photosynth Res 1992; 32:79-94. [PMID: 24408279 DOI: 10.1007/bf00035943] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/1991] [Accepted: 01/30/1992] [Indexed: 06/03/2023]
Abstract
The three genes of the pet operon, coding, respectively, for the Rieske iron-sulfur protein, cytochrome b and cytochrome c 1 components of the cytochrome bc 1 complex in the photosynthetic bacterium Rhodospirillum rubrum have been sequenced. The amino acid sequences deduced for these three peptides from the nucleotide sequences of the genes have been confirmed, in part, by direct sequencing of portions of the three peptides separated from a sample of the purified, detergent-solubilized complex. These sequences show considerable homology with those previously obtained for the pet operons of other photosynthetic bacteria. Northern blots of R. rubrum mRNA have established that the operon is transcribed as a single polycistronic message, the start site of which has been determined by both primer extension and nuclease protection. Photosynthetic growth of R. rubrum was shown to be inhibited by antimycin A, a specific inhibitor of cytochrome bc 1 complexes, and antimycin A-resistant mutants of R. rubrum have been isolated. Preliminary results suggest that it may be possible to express the R. rubrum pet operon in a strain of the photosynthetic bacterium Rhodobacter capsulatus from which the native pet operon has been deleted.
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Affiliation(s)
- S Chankor
- Department of Chemistry and Biochemistry, Texas Tech University, 79409-1061, Lubbock, TX, USA
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Güner S, Robertson DE, Yu L, Qiu ZH, Yu CA, Knaff DB. The Rhodospirillum rubrum cytochrome bc1 complex: redox properties, inhibitor sensitivity and proton pumping. Biochim Biophys Acta 1991; 1058:269-79. [PMID: 1646633 DOI: 10.1016/s0005-2728(05)80247-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A detergent-solubilized, three-subunit-containing cytochrome bc1 complex, isolated from the photosynthetic bacterium R. rubrum, has been shown to be highly sensitive to stigmatellin, myxothiazol, antimycin A and UHDBT, four specific inhibitors of these complexes. Oxidation-reduction titrations have allowed the determination of Em values for all the electron-carrying prosthetic groups in the complex. Antimycin A has been shown to produce a red shift in the alpha-band absorbance maximum of one of the cytochrome b hemes in the complex and stigmatellin has been shown to alter both the Em and EPR g-values of the Rieske iron-sulfur protein in the complex. Western blots have revealed antigenic similarities between the cytochrome subunits of the R. rubrum complex and those of the related photosynthetic bacteria, Rb. capsulatus and Rb. sphaeroides. The R. rubrum complex has been incorporated into liposomes. These liposomes exhibit respiratory control and are able to couple electron transfer from quinol to cytochrome c to proton translocation across the liposome membrane in a manner consistent with a Q-cycle mechanism. It can thus be concluded that neither electron transport nor coupled proton translocation by the cytochrome bc1 complex requires more than three subunits in R. rubrum.
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Affiliation(s)
- S Güner
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
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Hobbs DD, Kriauciunas A, Güner S, Knaff DB, Ondrias MR. Resonance Raman spectroscopy of cytochrome bc1 complexes from Rhodospirillum rubrum: initial characterization and reductive titrations. Biochim Biophys Acta 1990; 1018:47-54. [PMID: 2165419 DOI: 10.1016/0005-2728(90)90108-g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Resonance Raman spectra of bc1 complexes from Rhodospirillum rubrum have been obtained. Various resonance conditions and the stoichiometric redox titration of the complex were used to isolate and identify the contributions of the heme c1 and heme b active sites to the observed spectra. The complex was found to partially photoreduce when exposed to laser excitation.
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Affiliation(s)
- D D Hobbs
- Department of Chemistry, University of New Mexico, Albuquerque
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