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8 results on '"Parmaksiz, Ilker"'

1. First operation of a multi-channel Q-Pix prototype: measuring transverse electron diffusion in a gas time projection chamber

Author

Hoch, Nora, Seidel, Olivia, Chirayath, Varghese A., Enriquez, Alfredo, Gramellini, Elena, Guenette, Roxanne, Jaidee, I-See W., Keefe, Kevin, Kohani, Shahab, Kubota, Shion, Mahdy, Hany, McDonald, Austin, Mei, Yuan, Miao, Peng, Newcomer, F. Mitch, Nygren, David, Parmaksiz, Ilker, Rooks, Michael, Tzoka, Iakovos, Wei, Wenzhao, Asaadi, Jonathan, and Battat, James B. R.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report measurements of the transverse diffusion of electrons in P-10 gas (90% Ar, 10% CH4) in a laboratory-scale time projection chamber (TPC) utilizing a novel pixelated signal capture and digitization technique known as Q-Pix. The Q-Pix method incorporates a precision switched integrating transimpedance amplifier whose output is compared to a threshold voltage. Upon reaching the threshold, a comparator sends a 'reset' signal, initiating a discharge of the integrating capacitor. The time difference between successive resets is inversely proportional to the average current at the pixel in that time interval, and the number of resets is directly proportional to the total collected charge. We developed a 16-channel Q-Pix prototype fabricated from commercial off-the-shelf components and coupled them to 16 concentric annular anode electrodes to measure the spatial extent of the electron swarm that reaches the anode after drifting through the uniform field of the TPC. The swarm is produced at a gold photocathode using pulsed UV light. The measured transverse diffusion agrees with simulations in PyBoltz across a range of operating pressures (200-1500 Torr). These results demonstrate that a Q-Pix readout can successfully reconstruct the ionization topology in a TPC., Comment: 18 pages, 9 figures

Published
2024

3. Streptozotosin ile sıçanlarda oluşturulan diyabet modelinde aminoguanidinin serum nitrik oksit değerleri ve doku nitrik oksit sentaz ekspresyonu üzerine etkisi

Author

Parmaksiz, İlker, Şirikçi, Önder, and Biyokimya Anabilim Dalı

Subjects
Biyokimya, Biochemistry
Abstract

Diabetes Mellitus (DM) ileri evrede mikrovasküler ve makrovaskülerkomplikasyonlarla karşımıza çıkan metabolik bir hastalıktır. Yüksek glukozkonsantrasyonlarında dolaşımdaki veya dokulardaki proteinlerin non-enzimatikglikasyonu ile ileri glikasyon son ürünlerinin (AGE) oluştuğu bilinmektedir.AGE'ler, dolaşımdaki ve dokulardaki hücrelerin ve proteinlerin kalıcı kimyasalmodifikasyonuyla endotel disfonksiyonuna katkıda bulunmaktadır. DokulardaAGE'nin zamanla birikiminin nitrik oksit (NO) miktarını azalttığı gösterilmiştir. NO,endotelin vasküler tonusu düzenlenmesinde en önemli mediyatördür ve vaskülertonusun düzenlenmesindeki bozukluk, endotelin diğer fonksiyonlarındaki bozulmayıda yansıtmaktadır. Çalışmamızda streptozotosin ile oluşturulan diyabet modelindeAGE oluşumu inhibitörü olan aminoguanidin (AG) tedavisinin doku endotelyal nitrikoksit sentaz (eNOS) ekspresyonu ve serum nitrik oksit (NO) düzeylerine etkisiniincelemeyi amaçladık.Çalışmamızda, 10 haftalık erkek Sprague-Dawley sıçanlar 4 gruba ayrıldı veiki gruba Streptozotosin verilerek diyabet oluşturuldu. Bir grup ilaçsız takip edildi(DM). Diğer gruba AG verildi (DM+AG). Üçüncü grup sağlıklı kontrol (SK) olarakizlendi. Dördüncü gruba yalnızca AG verildi (SK+AG). 12 hafta sonunda sıçanlardankan, kalp ve böbrek dokularında glukoz, HbA1c, NO düzeyleri ve eNOSekspresyonları belirlendi.Kan NO düzeyleri DM ve SK+AG grubunda SK'ya göre anlamlı olarakazalmıştı. DM ile DM+AG gruplarının NO düzeyleri arasında ise anlamlı bir farkyoktu. Kalp dokusunda eNOS protein düzeyleri DM grubunda SK grubuna göreanlamlı olarak azalmıştı. DM+AG grubu eNOS düzeyleri DM grubuna göre anlamlıbir şekilde artmıştı. Dört grubun böbrek dokusu eNOS düzeyleri arasında istatistikselolarak anlamlı bir fark yoktu.Kan NO düzeyleri DM grubunda literatür ile uyumlu olarak azalmıştı. Kalpdokusunda eNOS protein düzeyleri DM grubunda azalmış bulunurken AGtedavisiyle anlamlı bir artış görüldü. AG'in böbrek ve diğer dokulardaki etkilerininve bazı çalışmalarda görülen yan etkilerinin daha iyi anlaşılabilmesi için ileriçalışmalara ihtiyaç duyulmaktadır.Anahtar kelimeler: Diyabet, nitrik oksit, streptozotosin, aminoguanidin, AGE Diabetes Mellitus is a metabolic disease, which results in microvascular andmacrovascular complications in later stages. It has been known that with elevatedglucose concentrations, proteins both in circulation and tissues are non-enzymaticallyglycated and these result in advanced glycation end-product (AGE) production.AGEs contribute to endothelial dysfunction by permanent chemical modifications ofproteins in circulation and in tissues. It was shown that AGE accumulation in tissuesdecrease NO concentration. NO is the most important mediator in the regulation ofvascular tonicity and any derangement observed in the regulation of the vasculartonicity also reflects the derangements in the functions of the endothelium. In ourstudy we aimed to investigate the effects of AGE inhibitor aminoguanidine (AG)treatment on tissue endothelial nitric oxide syntase (eNOS) expression and serum NOlevels in streptozotocin induced diabetic rats .In our study we enrolled 32 ten week-old male Sprague-Dawley rats into 4groups. In two groups diabetes was induced with streptozotocin. While one group(DM) was followed without any treatment, the other group was given AG(DM+AG). The third group was followed as healthy control (HC). The fourth groupwas given only AG (HC+AG). After 12 weeks, glucose, HbA1c, NO levels an eNOSexpressions were measured in blood samples and heart and kidney tissues.Blood NO levels were significantly lower in DM and SK+AG groupscompared to SK group. There was no significant difference between the NO levels ofDM and DM+AG groups. eNOS protein levels in heart tissues were significantlylower in DM group than the SK group. eNOS levels were significantly higher inDM+AG than DM group. There was no significant difference eNOS levels in kidneytissues between the four groups.Blood NO levels were lower in DM group, which was consistent with theliterature. While eNOS protein levels in heart tissues were lower in DM group, theirconcentration were increased with AG therapy. Further studies are needed tounderstand the effects of AG in kidney and other tissues and the side-effects thatwere seen in some studies.Key words: Diabetes Mellitus, nitric oxide, streptozotocin, aminoguanidine, AGE 68

Published
2009

6. Diyabet Komplikasyonlarinda İleri Glikasyon Son Ürünleri.

Author

Parmaksiz, İlker

Subjects
*DIABETES complications, *GLYCOSYLATION, *METABOLIC disorders, *MICROCIRCULATION disorders, *GLUCOSE, *CYTOKINES, *DIABETIC nephropathies, *NEUROPATHY
Abstract

Diabetes mellitus is a metabolic disease, which results in microvascular and macrovascular complications in later stages. It has been known that with elevated glucose concentrations, proteins in both the circulation and the tissues are non-enzymatically glycated and this results in the production of advanced glycation end-products. Advanced glycation end-products alter cell structure and function which lead to the synthesis and release of cytokines and growth factors. Therefore, advanced glycation end-products contribute to the microvascular and macrovascular complications of diabetes mellitus. Inhibition of advanced glycation was found to reduce diabetic complications such as nephropathy, retinopathy and neuropathy. Some of the agents that are used for the treatment of advanced glycation end-products formation and accumulation are summarized in this review [ABSTRACT FROM AUTHOR]

Published
2011
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