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A Comparative Evaluation of Polystyrene Divinylbenzene Copolymer HPLC Columns on the Chromatographic Performance of the Compendial Method for Doxycycline Hyclate Capsules: Implications for Method Implementation of a Medical Countermeasure Medication

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Journal of Analytical Sciences, Methods and Instrumentation 2015年第3期5卷 23-34页

作者： firat yerlikaya Adil Mohammad Patrick J. Faustino Mansoor A. Khan Saeed R. Khan Division of Product Quality Research Office of Testing and Research Office of Pharmaceutical Quality Center for Drug Evaluation and Research Food and Drug Administration Silver Spring MD USA

The purpose of this study was to evaluate the impact of polystyrene divinylbenzene copolymer HPLC columns on the chromatographic performance of the USP compendial method for doxycycline hyclate. The compendial method was implemented based on the assessment of the chromatographic performance of six USP defined L21 polystyrene divinylbenzene HPLC columns. Modifications to the method were based on USP for chromatography. The method was validated for the determination of doxycycline hyclate and its impurities in commercially available drug products. A number of different polystyrene-divinylbenzene columns were tested and failed to provide selectivity for the resolution of doxycycline and its impurities. Separation was optimally achieved on an Agilent PLPR-S column (250 × 4.6 mm, 8 μm) by using an Agilent 1260 series HPLC system. Doxycycline hyclate and its impurities were eluted isocratically at a flow rate of 1 mL/min with mobile phase and detected at 270 nm. The column temperature was maintained at 60oC. The method was validated according to USP category I requirements for Assay. Validation acceptance criteria were met in all cases. The analytical range for doxycycline hyclate was 50 - 250 μg/mL and the linearity was r2 > 0.999 over three days. The method was determined to be specific. Both accuracy (95.1% - 102.4%) and precision (0.50% - 4.8%) were established across the analytical range for low, intermediate and high QC concentrations. Method applicability was demonstrated by analyzing marketed products of doxycycline hyclate, in which results showed potency meeting USP acceptance criteria. In conclusion, this study described the remarkable differences in selectivity that were encountered during the implementation phase for the compendial methods for doxycycline and its impurities in marketed products and it could be used in the future to assss the product quality of doxycycline hyclate capsules stored in the National stockpiles.

关键词： Doxycycline 4-Epidoxycycline 6-Epidoxycycline Metacycline Polystyrene-Divinylbenzene

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Femoral Access with Ultrasound-Guided Puncture and Z-Stitch Hemostasis for Adults with Congenital Heart Diseases Undergoing Electrophysiological Procedures

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Congenital Heart Disease 2024年第1期19卷 85-92页

作者： Fu Guan Matthias Gass Florian Berger Heiko Schneider firat Duru Thomas Wolber Arrhythmia and Electrophysiology Division Department of CardiologyUniversity Heart Center ZurichZurichSwitzerland Children’s Research Center Zurich University Children’s HospitalZurichSwitzerland Center for Integrative Human Physiology University of ZurichZurichSwitzerland

Aims:Although the application of ultrasound-guided vascular puncture and Z-stitch hemostasis to manage femoral access has been widely utilized,there is limited data on this combined application in adult congenital heart disease(ACHD)patients undergoing electrophysiological(EP)*** sought to evaluate the safety and efﬁcacy of ultrasound-guided puncture and postprocedural Z-stitch hemostasis for ACHD patients under-going EP *** and Results:The population of ACHD patients undergoing transfemoral EP pro-cedures at the University of Zurich Heart Center between January 2019 and December 2022 was observed and *** the study period,femoral access(left/right,arterial/venous)was performed under real-time ultrasound *** the end of the procedure,a single Z-stitch was performed at the puncture *** eval-uated the incidence of in-hospital complications associated with femoral access puncture in this *** 101 patients who had a total of 147 previous ipsilateral vascular punctures(mean 1.5 per person),100 patients underwent successful femoral vascular access for EP *** median age of the patients was 47±15 years and 34(34%)were male.Z-stitches were performed after the procedure in 100 patients with 303 femoral vascular accesses(mean 3 punctures per person).No patient developed vascular puncture relevant inguinal hematoma,pseudo aneurysm,arteriovenousﬁstula,venous or arterial ***:In ACHD patients undergoing EP procedures,optimal femoral access management can be achieved with ultra-sound-guided puncture and postprocedural Z-stitch hemostasis.

关键词： Congenital heart disease cardiac electrophysiology cardiac catheterization femoral access hemostasis

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PBX/Knotted 1 homeobox-2(PKNOX2)is a novel regulator of myocardial fibrosis

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Signal Transduction and Targeted Therapy 2024年第5期9卷 2231-2249页

作者： Liang Chen Haotong Li Xiaorui Liu Ningning Zhang Kui Wang Anteng Shi Hang Gao Deniz Akdis Ardan MSaguner Xinjie Xu Elena Osto Willem Van de Veen Guangyu Li Antoni Bayés-Genís firat Duru Jiangping Song Xiangjie Li Shengshou Hu State Key Laboratory of Cardiovascular Disease Fuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP.R.China School of Statistics and Data Science Nankai UniversityTianjinChina Department of Cardiology University Heart CenterUniversity Hospital Zurich and University of ZurichZurichSwitzerland Institute for Clinical Chemistry University Hospital Zurich and University of ZürichZurichSwitzerland Swiss Institute of Allergy and Asthma Research(SIAF) University of ZurichDavosSwitzerland Heart Institute Hospital Universitari Germans Trias i PujolBadalonaCIBERCVSpain

Much effort has been made to uncover the cellular heterogeneities of human hearts by single-nucleus RNA ***,the cardiac transcriptional regulation networks have not been systematically described because of the limitations in detecting transcription *** this study,we optimized a pipeline for isolating nuclei and conducting single-nucleus RNA sequencing targeted to detect a higher number of cell signal genes and an optimal number of transcription *** this unbiased protocol,we characterized the cellular composition of healthy human hearts and investigated the transcriptional regulation networks involved in determining the cellular identities and functions of the main cardiac cell *** in fibroblasts,a novel regulator,PKNOX2,was identified as being associated with physiological fibroblast activation in healthy *** validate the roles of these transcription factors in maintaining homeostasis,we used single-nucleus RNA-sequencing analysis of transplanted failing hearts focusing on fibroblast *** trajectory analysis suggested that PKNOX2 was abnormally decreased from fibroblast activation to pathological myofibroblast *** gain-and loss-of-function in vitro experiments demonstrated the inhibitory role of PKNOX2 in pathological fibrosis ***,fibroblast-specific overexpression and knockout of PKNOX2 in a heart failure mouse model induced by transverse aortic constriction surgery significantly improved and aggravated myocardial fibrosis,*** summary,this study established a high-quality pipeline for single-nucleus RNA-sequencing analysis of heart *** this optimized protocol,we described the transcriptional regulation networks of the main cardiac cell subtypes and identified PKNOX2 as a novel regulator in suppressing fibrosis and a potential therapeutic target for future translational studies.

关键词： NOX2 homeostasis fibrosis

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Spiraea cudidaghense:a new species from south-eastern Anatolia,Turkey

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Journal of Forestry Research 2018年第6期29卷 1751-1756页

作者： Mehmet firat Necmi Aksoy Department of Biology Faculty of EducationYuzucu Yil University65080 VanTurkey Faculty of Forestry&DUOF Herbarium Duzce University81620 DuzceTurkey

A new species, Spiraea cudidaghense(sect. Spiraeoideae, Rosaceae), is described and illustrated with diagnostic characters and taxonomic comments. Its characteristics are compared with those of the type species from which it differs mainly in compound corymbs inflorescence, ovate-obovate leaves, white petals, glabrous branches and densely pilose corymbs. In addition, a map of the geographic distribution of the new species, an IUCN ranking and notes on taxonomic affinities are also provided.

关键词： Spiraea cudidaghense Taxonomy New species Turkey

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Electrochemical sensor investigation of carbon-supported PdCoAg multimetal catalysts using sugar-containing beverages

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Frontiers of Chemical Science and Engineering 2020年第4期14卷 629-638页

作者： firat Salman Hilal C.Kazici Hilal Kivrak Department of Chemical Engineering Faculty of EngineeringVan Yizinci Yil University65000 VanTurkey

Novel PdCoAg/C nanostructures were suc-cessfully synthesized by the polyol method in order to develop electrocatalysts,related to the glucose sensor performance of the high glycemic index in *** characterization of this novel PdCoAg/C electrocatalyst was performed by X-ray diffraction,scanning electron microscopy,transmission clectron microscopy,and high-resolution transmission electron microscopy equipped with energy dispersive *** characterization results revealed that electronic state of the PdCoAg/C electro-catalyst was modified by the addition of the third *** electrochemical performances of the sensor were investigated by cyclic voltammetry and differential pulse *** prepared enzyme-free sensor exhibited excellent catalytic activity against glucose with a wide detection range(0.005 to 0.35 mmol·L^-1),low limit of detection(0.003 mmol·L^-1),high sensitivity(4156.34μA·mmol^-1·L·cm^-3),and long-term stability(10 days)because of the synergistic effect between the termary *** glucose contents of several energy drinks,fruit juices,and carbonated beverages were analyzed using the novel PdCoAgNGCE/C sensor *** results indicate the feasibility for applications in the foods industry.

关键词： non-enzymatic glucose detection ternary metals glycemic index beverages

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A review on the gun barrel vibrations and control for a main battle tank

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Defence Technology（防务技术） 2017年第5期13卷 353-359页

作者： Tolga Dursun firat Biiyiikcivelek Cagrihan Utlu Aselsan Inc MGEO Division CankiriYolu 7.km AkyurtAnkara 06750Turkey

Achieving high hitting accuracy for a main battle tank is challenging while the tank is on the move. This can be reached by proper design of a weapon control and gun system. In order to design an effective gun system while the tank is moving, better understanding of the dynamic behavior of the gun system is required. In this study, the dynamic behaviour of a gun system is discussed in this respect. Both experimental and numerical applications for the determination of the dynamic behaviour of a tank gun system are investigated. Methods such as the use of muzzle reference system(MRS) and vibration absorbers, and active vibration control technology for the control and the reduction of the muzzle tip deflections are also reviewed. For the existing gun systems without making substantial modifications,MRS could be useful in controlling the deflections of gun barrels with estimation/prediction *** vibration levels could be cut into half by the use of optimised vibration absorbers for an existing gun.A new gun system with a longer barrel can be as accurate as the one with a short barrel with the appropriate structural modifications.

关键词： Gun dynamics Vibration control Muzzle reference system Vibration absorber

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Topiramate as a neuroprotective agent in a rat model of spinal cord injury

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Neural Regeneration Research 2017年第12期12卷 2071-2076页

作者： firat Narin Sahin Hanalioglu Huseyin Ustun Kamer Kilinc Burcak Bilginer Department of Neurosurgery Hacettepe University Faculty of Medicine Ankara Turkey Department of Pathology Ankara Training and Research Hospital Ankara Turkey Department of Biochemistry TOBB University of Economics and Technology Faculty of Medicine Ankara Turkey

Topiramate（TPM） is a widely used antiepileptic and antimigraine agent which has been shown to exert neuroprotective effects in various experimental traumatic brain injury and stroke models. However, its utility in spinal cord injury has not been studied extensively. Thus, we evaluated effects of TPM on secondary cellular injury mechanisms in an experimental rat model of traumatic spinal cord injury（SCI）. After rat models of thoracic contusive SCI were established by free weight-drop method, TPM（40 mg/kg） was given at 12-hour intervals for four times orally. Post TPM treatment, malondialdehyde and protein carbonyl levels were significantly reduced and reduced glutathione levels were increased, while immunoreactivity for endothelial nitric oxide synthase, inducible nitric oxide synthase, and apoptotic peptidase activating factor 1 was diminished in SCI rats. In addition, TPM treatment improved the functional recovery of SCI rats. This study suggests that administration of TPM exerts neuroprotective effects on SCI.

关键词： nerve regeneration spinal cord injury topiramate neuroprotection oxidative damage nitricoxide motor function neural regeneration

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Numerical and back analysis-based methodology for support design of cut slopes at the Turkish – Georgian Border(NE Turkey)

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Journal of Mountain Science 2021年第6期18卷 1678-1695页

作者： Muhammet Oğuz SÜNNETCI Hakan ERSOY Arzu firat ERSOY Karadeniz Technical University Dept.of Geological EngineeringTrabzon 61080Turkey

In this study, geophysical and geotechnical studies were carried out in NE Turkey to evaluate the stability and support design of cut slopes that will be excavated during the construction of a new border control complex. 13 vertical and 3 inclined boreholes were drilled, and 2D electrical resistivity tomography surveys were conducted along 8 profiles to investigate the horizontal and vertical continuity of the geological units. Strength characteristics of all units were determined by laboratory tests. Limit equilibrium(LE) slope stability analyses were conducted on the geological model for static and pseudo-static conditions and factor of safety values as low as 0.227 were determined for post-excavation. Back analysis was conducted for the determination of required support forces on the slopes to achieve a factor of safety of 1.3. A feasible support system consisting of bored piles and rock anchors was designed based on back analysis results for each cut slope. LE analyses were repeated after the implementation of the designed support systems and the lowest factor of safety value increased to 1.35. The utility and safety of the designed support systems were investigated using finite element slope stability analyses and strength reduction factor values higher than 1.3 were determined which means support systems will function as intended and no support failure will occur. Lastly, quick reference charts were created for alluvium and residual soil materials to easily determine the safe slope angle in the future in case no support measures will be applied.

关键词： Slope stability 2D electrical resistivity Geotechnical studies Finite element Sensitivity analysis Back analysis

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Evaluation of ischemic lesions after carotid artery stenting with diffusion-weighted imaging

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World Journal of Clinical Cases 2020年第10期8卷 1859-1870页

作者： Murat Beyhan Berat Acu Erkan Gokce Mehmet Murat firat Department of Radiology Tokat Gaziosmanpasa University Faculty of MedicineTokat 60100Turkey Department of Radiology Eskisehir Osmangazi University Faculty of MedicineEskisehir 26480Turkey Department of Radiology Guven HospitalAnkara 06540Turkey

BACKGROUND Almost 90%of cerebral thromboembolism cases are caused by *** atherosclerosis is often observed at the carotid bifurcation and is responsible for 20%-30%of all stroke *** course of atherosclerotic carotid artery stenosis varies depending on the grade of stenosis and characteristics of the *** artery stenting(CAS)can be used as a less invasive method in patients with symptomatic and asymptomatic high-grade carotid artery ***-weighted imaging(DWI)is an effective method for detection of silent or symptomatic acute ischemic lesions that may arise due to CAS or carotid *** number and volume of new ischemic lesions are determined using *** To evaluate the number and volume of ischemic lesions and their cerebral parenchymal and vascular distribution after CAS using *** Forty-seven male(73.4%)and seventeen female(26.6%)patients(total,n=64)aged 42-84 years(mean 67.96±8.03 years)diagnosed with carotid stenosis between October 2006 and July 2012 were included in this retrospective *** of the cases(18.8%)were asymptomatic,while fifty-two(81.2%)were *** area where the stenosis was highest was measured,and the stenosis rate was determined using the North American Symptomatic Carotid Endarterectomy Trial *** of the cases was evaluated by two radiologists experienced in neuroradiology(*** more than 15 years of experience,*** more than 10 years of experience).Routine DWI examinations were carried out by a 1.5 T MR device 1 h before and after the *** the ischemic lesions that developed in the first hour and in the follow-up period of 5-24 h were assumed to be due to CAS,all lesions within the first 24 h were considered as new *** In the present study,39 new ischemic lesions were detected in 20 *** average number of new lesions after all CAS operations was *** were mostly located in the occipital lobes,followed by

关键词： Carotid artery stenosis Carotid artery stenting Diffusion-weighted imaging Ischemia Stroke

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PCP-Ed: Parallel coordinate plots for ensemble data

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Visual Informatics 2023年第1期7卷 56-65页

作者： Elif E.firat Ben Swallow Robert S.Laramee University of Nottingham UK University of Glasgow UK

The Parallel Coordinate Plot(PCP)is a complex visual design commonly used for the analysis of high-dimensional *** data size and complexity may make it challenging to decipher and uncover trends and outliers in a confined space.A dense PCP image resulting from overlapping edges may cause patterns to be *** develop techniques aimed at exploring the relationship between data dimensions to uncover trends in dense *** introduce correlation glyphs in the PCP view to reveal the strength of the correlation between adjacent axis pairs as well as an interactive glyph lens to uncover links between data dimensions by investigating dense areas of edge *** also present a subtraction operator to identify differences between two similar multivariate data sets and relationship-guided dimensionality reduction by collapsing axis *** finally present a case study of our techniques applied to ensemble data and provide feedback from a domain expert in epidemiology.

关键词： Parallel coordinates Overplotting Ensemble data

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