Genome-wide Analysis of Iron-Regulated Transporter 1 (IRT1) Genes in Plants

Recep Vatansever,Ertugrul Filiz,Ibrahim Ilker Ozyigit 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.4

Iron (Fe) is an essential micronutrient required in a number of biological processes in plant species. Fe transporters are a type of broad-range metal transporter and have different families functioning in different compartments. This study focused on iron-regulated transporter 1 (IRT1), which are mainly responsible for Fe uptake from root, in 17 selected plant species with an emphasis on Brachypodium distachyon, Chlamydomonas reinhardtii, Solanum lycopersicum and Populus trichocarpa species. All IRT1 proteins were observed to belong to the ZIP (PF02535) protein family with eight transmembrane (TM) domains, and have a similar molecular weight (33.86-42.72 kDa, except for C. reinhardtii with 65.83 kDa) and amino acid length (324-408 aa, except for C. reinhardtii with 639 aa), with pI values of 5.31-7.16. The sub-cellular localization of these proteins was predicted to be the plasma membrane. Similar exon numbers were also detected with most genes having 2-3, except for C. reinhardtii (5), Physcomitrella patens (5) and Vitis vinifera (4). In a phylogenetic tree, monocot-dicot separation was not observed in main groups but some subgroups included only monocot or dicot proteins. Predicted interaction partner analysis of AtIRT1 (AT2G30080.1) pointed to main interaction partners either directly related with iron transport or that of other metal ion. The results of this study provide a theoretical reference for elucidating the structural and biological role of IRT1 genes/proteins in plant species.

Analytical investigation of thin steel plate shear walls with screwed infill plate

Cüneyt vatansever,Jeffrey W. Berman 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.5

A behavior model for screw connections is developed to provide a better representation of the nonlinear response of thin steel plate shear walls (TSPSWs) with infill plates attached to the boundary frame members via self-drilling screws. This analytical representation is based on the load-bearing deformation relationship between the infill plate and the screw threads. The model can be easily implemented in strip models of TSPSWs where the tension field action of the infill plates is represented by a series of parallel discrete tension-only strips. Previously reported experimental results from tests of two different TSPSWs are used to provide experimental validation of the modeling approach. The beam-to-column connection behavior was also included in the analyses using a four parameter rotational spring model that was calibrated to a test of an identical frame as used for the TSPSW specimens but without the infill plates. The complete TSPSW models consisting of strips representing the infill plates, zero length elements representing the load-bearing deformation response of the screw connection at each end of the strips and the four parameter spring model at each beam-to-column connection are shown to have good agreement with the experimental results. The resulting models should enable design and analysis of TSPSWs for both new construction and retrofit of existing buildings.

Surface-Initiated Polymerization with Poly(n-hexylisocyanate) to Covalently Functionalize Silica Nanoparticles

Fatma Vatansever,Michael R. Hamblin 한국고분자학회 2017 Macromolecular Research Vol.25 No.2

New methods are needed for covalent functionalization of nanoparticles-surface with organic polymer coronas to generate polymeric nanocomposite in a controlled manner. Here we report the use of a surface-initiated polymerization approach, mediated by titanium(IV) catalysis, to grow poly(n-hexylisocyanate) chains from silica surface. Two pathways were used to generate the interfacing in these nano-hybrids. In the first one, the nanoparticles were “seeded” with SiCl4, followed by reaction with 1,6-hexanediol to form hydroxyl groups attached directly to the surface via O-Si-O bonding. In the second pathway, the nanoparticles were initially exposed to a 9:1 mixture of trimethyl silyl chloride and chlorodimethyl octenyl silane which was then followed by hydroboration of the double bonds, to afford hydroxyl groups with a spatially controlled density and surface-attachment via O-Si-C bonding. These functionalized surfaces were then activated with the titanium tetrachloride catalyst. In our approach, surface tethered catalyst provided the sites for n-hexyl isocyanate monomer insertion to “build up” the surface-grown polymer layers from the “bottom-up”. A final end-capping, to seal off the chain ends, was done via acetyl chloride. Compounds were characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (NMR), gas chromatography-mass spectrometry (GC-MS), gel permeation chromatography (GPC), and thermogravimetric analyses.

Experimental investigation of thin steel plate shear walls with different infill-to-boundary frame connections

Cüneyt vatansever,Nesrin yardimci 국제구조공학회 2011 Steel and Composite Structures, An International J Vol.11 No.3

To make direct comparisons regarding the cyclic behavior of thin steel plate shear walls (TSPSWs) with different infill-to-boundary frame connections, two TSPSWs were tested under quasi-static conditions, one having the infill plate attached to the boundary frame members on all edges and the other having the infill plate connected only to the beams. Also, the bare frame that was used in the TSPSW specimens was tested to provide data for the calibration of numerical models. The connection of infill plates to surrounding frames was achieved through the use of self-drilling screws to fish plates that were welded to the frame members. The behavior of TSPSW specimens are compared and discussed with emphasis on the characteristics important in seismic response, including the initial stiffness, ultimate strength and deformation modes observed during the tests. It is shown that TSPSW specimens achieve significant ductility and energy dissipation while the ultimate failure mode resulted from infill plate fracture at the net section of the infill plate-to-boundary frame connection after substantial infill plate yielding. Experimental results are compared to monotonic pushover predictions from computer analysis using strip models and the models are found to be capable of approximating the monotonic behavior of the TSPSW specimens.

Effect of bolted splice within the plastic hinge zone on beam-to-column connection behavior

Cüneyt vatansever,Kutay Kutsal 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.6

The purpose of this study is to investigate how a fully restrained bolted beam splice affects the connection behavior as a column-tree connection in steel special moment frames under cyclic loading when located within the plastic hinge zone. The impacts of this attachment in protected zone are observed by using nonlinear finite element analyses. This type of splice connection is designed as slip-critical connection and thereby, the possible effects of slippage of the bolts due to a possible loss of pretension in the bolts are also investigated. The 3D models with solid elements that have been developed includes three types of connections which are the connection having fully restrained beam splice located in the plastic hinge location, the connection having fully restrained beam splice located out of the plastic hinge and the connection without beam splice. All connection models satisfied the requirement for the special moment frame connections providing sufficient flexural resistance, determined at column face stated in AISC 341-16. In the connection model having fully restrained beam splice located in the plastic hinge, due to the pretension loss in the bolts, the friction force on the contact surfaces is exceeded, resulting in a relative slip. The reduction in the energy dissipation capacity of the connection is observed to be insignificant. The possibility of the crack occurrence around the bolt holes closest to the column face is found to be higher for the splice connection within the protected zone.

Cyclic testing of chevron braced steel frames with IPE shear panels

Alirıza İ. Akgönen,Cavidan Yorgun,Cüneyt Vatansever 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.5

The aim of this experimental research is to investigate the conformity of the four-bolt unstiffened moment end-plate connections consisting of European steel sections which do not meet the limitations specified for beam flange width and overall beam depth in ANSI/AISC 358-10 to the requirements of seismic application. However, the connections are satisfactory with the limitations required by Turkish Earthquake Code. For this purpose, four test specimens were designed and cyclic load was applied to three specimens while one was tested under monotonic loading to provide data for the calibration of the analytical models. The moment-rotation hysteresis loops and the failure modes for all test specimens are presented. A full three-dimensional finite element model is also developed for each test specimen for use to predict their behavior and to provide a tool for generating subsequent extensive parametric studies. The test results show that all specimens performed well in terms of rotation capacity and strength. Finite element models are found to be capable of approximating the cyclic behavior of the extended end-plate connection specimens.

Preparation and Characterization of Silver Cyclohexane Mono Carboxylate : β-Cyclodextrine Inclusion Complexes and Obtaining Wash-Resistant Antibacterial Effect on Cotton Fabrics

Riza Atav,Aylin Yildiz,Derman Vatansever Bayramol,A. Ozgur Agirgan,Mine Aydin Kurc 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10

In this study, inclusion complexes were prepared according to kneading and physical mixing techniques at 1:1 and1:2 (guest:host) mass ratios of silver cyclohexane mono carboxylate:β-cyclodextrin. Prepared complexes were analyzed byusing fourier transformed infrared spectroscopy, thermogravimetric analyses and scanning electron microscope. With regardto the obtained results, inclusion complex formation was observed with silver cyclohexane mono carboxylate and β-cyclodextrin at a mass ratio of both 1:1 and 1:2. In addition to preparation and characterization of inclusion complexes, theywere applied on cotton fabrics via pad-dry method. In order to investigate the wash resistance of antibacterial effect, inclusioncomplex containing cotton fabrics were repeatedly washed and tested up to 50 washes. It was determined that cotton fabricsloaded with Ag-CC:β-CD 1:2 inclusion complexes showed antimicrobial efficiency against S. aureus, B. subtilis and P. aeruginosa even after 50 washings.

Tertiary Cytoreduction for Recurrent Epithelial Ovarian Cancer: a Multicenter Study in Turkey

Arvas, Macit,Salihoglu, Yavuz,Sal, Veysel,Gungor, Tayfun,Sozen, Hamdullah,Kahramanoglu, Ilker,Topuz, Samet,Demirkiran, Fuat,Iyibozkurt, Cem,Bese, Tugan,Ozgu, Burcin Salman,Vatansever, Dogan,Tokgozoglu Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.4

Background: The purpose of this study was to determine the benefit of tertiary cytoreductive surgery (TC) for secondary recurrent epithelial ovarian cancer (EOC), focusing on whether optimal cytoreduction has an impact on disease-free survival, and whether certain patient characteristics could identify ideal candidates for TC. Materials and Methods: Retrospective analysis of secondary recurrent EOC patients undergoing TC at three Turkish tertiary institutions from May 1997 to July 2014 was performed. All patients had previously received primary cytoreduction followed by intravenous platinum-based chemotherapy and secondary cytoreduction for first recurrence. Clinical and pathological data were obtained from the patients' medical records. Survival analysis was caried out using the Kaplan Meier method. Actuarial curves were compared by the two tailed Logrank test with a statistical significance level of 0.05. Results: Median age of the patients was 49.6 years (range, 30-67) and thirty-eight (72%) had stage III-IV disease at initial diagnosis. Twenty six (49%) had optimal and 27 (51%) suboptimal cytoreduction during tertiary debulking surgery. Optimal initial cytoreduction, time to first recurrence, optimal secondary cytoreduction, time interval between secondary cytoreduction and secondary recurrence, size of recurrence, disease status at last follow-up were found to be significant risk factors to predict optimal TC. Optimal cytoreduction in initial and tertiary surgery and serum CA-125 level prior to TC were independent prognostic factors on univariate analysis. Conclusions: Our results and a literature review clearly showed that maximal surgical effort should be made in TC, since patients undergoing optimal TC have a better survival. Thus, patients with secondary recurrent EOC in whom optimal cytoreduction can be achieved should be actively selected.

A Comparison of the Effects of Dexamethasone and Methylprednisolone, Used on Level-3 Intensive Care COVID-19 Patients, on Mortality: A Multi-Center Retrospective Study

Sari Ahmet,Ekinci Osman,Saraçoğlu Kemal Tolga,Balık Recep,Aslan Mesut,Balık Yelda,Önal Ceren,Aslan Murat,Cevher Semra,Parmaksız Aylin,Vatansever Şule,Çicek Münire Canan,Ayan Özge Sayın,Şensöz Çelik Ga 대한의학회 2023 Journal of Korean medical science Vol.38 No.29

Background: Coronavirus disease 2019 (COVID-19) is often a mild disease, usually manifesting with respiratory complaints, and is sometimes mortal due to multiple organ failure. Hyperinflammation is a known COVID-19 component and is associated with organ dysfunction, disease severity and mortality. Controlling hyperinflammatory response is crucial in determining treatment direction. An important agent in providing this control is corticosteroids. This study aimed to determine whether dexamethasone and methylprednisolone, doses, administration time and duration in COVID-19 treatment are associated with improved treatment outcomes. Methods: This retrospective multicenter study was conducted with participation of 6 healthcare centers which collected data by retrospectively examining files of 1,340 patients admitted to intensive care unit due to COVID-19 between March 2020 and September 2021, diagnosed with polymerase chain reaction (+) and/or clinically and radiologically. Results: Mortality in the pulse methylprednisolone group was statistically significantly higher than that in the other 3 groups. Mortality was higher in older patients with comorbidities such as hypertension, diabetes mellitus, chronic kidney failure, coronary artery disease, and dementia. Pulse and mini-pulse steroid doses were less effective than standard methylprednisolone and dexamethasone doses, pulse steroid doses being associated with high mortality. Standard-dose methylprednisolone and dexamethasone led to similar effects, but standard dose methylprednisolone was more effective in severe patients who required mechanical ventilation (MV). Infection development was related to steroid treatment duration, not cumulative steroid dose. Conclusion: Corticosteroids are shown to be beneficial in critical COVID-19, but the role of early corticosteroids in mild COVID-19 patients remains unclear. The anti-inflammatory effects of corticosteroids may have a positive effect by reducing mortality in severe COVID-19 patients. Although dexamethasone was first used for this purpose, methylprednisolone was found to be as effective at standard doses. Methylprednisolone administered at standard doses was associated with greater PaO2/FiO2 ratios than dexamethasone, especially in the severe group requiring MV. High dose pulse steroid doses are closely associated with mortality and standard methylprednisolone dose is recommended.