Erişime Açık

Delayed feedback and detection of weak periodic signals in a stochastic Hodgkin-Huxley neuron

Yılmaz, Ergin | Özer, Mahmut

We study the effect of the delayed feedback loop on the weak periodic signal detection performance of a stochastic Hodgkin-Huxley neuron. We consider an electrical autapse characterized by its coupling strength and delay time. The stochastic Hodgkin-Huxley neuron exhibits subthreshold oscillations, and thus has an intrinsic time scale with the subthreshold oscillations. Therefore, we investigate the interplay of the subthreshold oscillations, coupling strength and delay time on the weak periodic signal detection. Results indicate that the delayed feedback either enhances or suppresses the weak ...Daha fazlası

Makale 2015 Physica A: Statistical Mechanics and its Applications421 , pp. 4 - 462 339 Görüntülenme

Effect of channel noise on the time-course of recovery from inactivation of sodium channels

Özer, Mahmut | Ekmekçi, N. Hakan

Ion channel noise that stems from the stochastic nature of the channel has important effects on neuronal dynamics. In this context, we examine the effect of the channel noise on the time-course of recovery from inactivation of sodium channels by using a stochastic extension of the Hodgkin-Huxley model. We show that the channel noise provides both some amount of the non-inactivated channels and a smaller time-course for recovering from inactivation leading to an increased maximal sodium conductance compared to deterministic one. © 2005 Elsevier B.V. All rights reserved.

Makale 2005 Physics Letters, Section A: General, Atomic and Solid State Physics338 ( 2 ) , pp. 1 - 154 720 Görüntülenme

Vibrational resonance in a heterogeneous scale free network of neurons

Uzuntarla, Muhammet | Yılmaz, Ergin | Wagemakers, Alexandre | Özer, Mahmut

Vibrational resonance (VR) is a phenomenon whereby the response of some dynamical systems to a weak low-frequency signal can be maximized with the assistance of an optimal intensity of another high-frequency signal. In this paper, we study the VR in a heterogeneous neural system having a complex network topology. We consider a scale-free network of neurons where the heterogeneity is in the intrinsic excitability of the individual neurons. It is shown that emergence of VR in heterogeneous neuron population requires less energy than a homogeneous population. We also find that electrical coupling ...Daha fazlası

Makale 2015 Communications in Nonlinear Science and Numerical Simulation22 ( 01.Mar ) , pp. 3 - 374 275 Görüntülenme

Erişime Açık

Morphine modulates inducible nitric oxide synthase expression and reduces pulmonary oedema induced by α-naphthylthiourea

Cömert, Mustafa | Sipahi, Emine Yılmaz | Üstün, Hüseyin | Işıkdemir, Fulden | Numanoğlu, Gamze | Barut, Figen | Altunkaya, Hanife | Özer, Yetkin | Ayoğlu, Ferruh Niyazi | Sipahi, Tunç Hakan | Tekin, İshak Özel | Banoğlu, Z. Nur

This study was designed to investigate the possible participation of morphine in pulmonary oedema induced by ?-naphthylthiourea (ANTU), which is a well-known noxious chemical agent in the lung. Injection of ANTU (15 mg/kg i.p.) produced pulmonary oedema as indicated by an increase in lung weight/body weight ratio and pleural effusion reaching a maximum within 4 h in rat. Administration of morphine prior to ANTU significantly inhibited to pulmonary oedema with a dose-dependent manner. The protective effect of morphine is prevented by peripheral opioid receptor antagonist, naloxone methiodide. A ...Daha fazlası

Makale 2005 European Journal of Pharmacology511 ( 02.Mar ) , pp. 1 - 189 1704 Görüntülenme

Enhancement of temporal coherence via time-periodic coupling strength in a scale-free network of stochastic Hodgkin-Huxley neurons

Yılmaz, Ergin | Baysal, Veli | Özer, Mahmut

We investigate the effects of time-periodic coupling strength on the temporal coherence or firing regularity of a scale-free network consisting of stochastic Hodgkin-Huxley (H-H) neurons. The temporal coherence exhibits a resonance-like behavior depending on the cell size or the channel noise intensity. The best temporal coherence requires an optimal channel noise intensity, and this coherence can be significantly increased by time-periodic coupling strength when its frequency matches the integer multiples of the intrinsic subthreshold oscillation frequency of H-H neuron. Particularly, we find ...Daha fazlası

Makale 2015 Physics Letters, Section A: General, Atomic and Solid State Physics379 ( 26-27 ) , pp. 1 - 1599 837 Görüntülenme

Genetic variants of estrogen beta and leptin receptors may cause gynecomastia in adolescent

Eren E. | Edgunlu T. | Korkmaz H.A. | Cakir E.D.P. | Demir K. | Cetin E.S. | Celik S.K.

Objective: Gynecomastia is a benign breast enlargement in males that affects approximately one-third of adolescents. The exact mechanism is not fully understood; however, it has been proposed that estrogen receptors and aromatase enzyme activity may play important roles in the pathogenesis of gynecomastia. While many studies have reported that aromatase enzyme (CYP19) gene polymorphism is associated with gynecomastia, only one study has shown a relationship between estrogen receptor (ER) alpha and beta gene polymorphism and gynecomastia. Thus, the aim of this study was to evaluate the relation ...Daha fazlası

Makale 2014 Gene541 ( 2 ) , pp. 1 - 106 576 Görüntülenme

High nitrate intake impairs liver functions and morphology in rats; Protective effects of ?-tocopherol

Ogur R. | Coskun O. | Korkmaz A. | Oter S. | Yaren H. | Hasde M.

The aim of this study was to determine the effect of high dose nitrate ingested in drinking water, on liver enzymes and histopathology, liver weight/body weight (lw/bw) ratio, serum and liver malondialdehyde (MDA) levels and osmotic fragility in Sprague-Dawley rats. These parameters were compared on 40 rats divided into four groups; control animals (group A) drank filtered tap water containing maximum 10 mg/L nitrate while treatment groups drank 200 mg/L (group B), 400 mg/L (group C) and ?-tocopherol plus 400 mg/L (group D) nitrate containing water ad libitum for 60 days. As a result, lw/bw ra ...Daha fazlası

Makale 2005 Environmental Toxicology and Pharmacology20 ( 1 ) , pp. 1 - 166 417 Görüntülenme

Novel ruthenium(II)-N-heterocyclic carbene complexes; Synthesis, characterization and catalytic application

Yaşar S. | Karaca E.Ö. | Şahin Ç. | Özdemir I. | Şahin O. | Büyükgüngör O.

The synthesis of highly active ruthenium(II) catalyst based on N-heterocyclic carbene (NHC) bearing alkyl and aryl groups is reported. The complexes are easily handled in very good yields via synthesis of silver-NHC complexes and subsequent reaction with [RuCl2(p-cymene)]2 in dichloromethane (DCM) under N2 condition. All new compounds were characterized by LC-MSMS, elemental analysis, NMR spectroscopy and X-ray diffraction. With the development of a more efficient catalytic system for transfer hydrogenation of aryl ketones and aldehydes in mind, the catalytic performance of the Ru-NHC complexe ...Daha fazlası

Makale 2015 Journal of Organometallic Chemistry789-790 , pp. 1 - 7 391 Görüntülenme

May TLR4 Asp299Gly and IL17 His161Arg polymorphism be associated with progression of primary measles infection to subacute sclerosing panencephalitis?

Karakas-Celik S. | Piskin I.E. | Keni M.F. | Calik M. | Iscan A. | Dursun A.

SSPE is a progressive neurological disorder of children. Only some of the children who are infected with measles virus develop SSPE, which supports individual variation. TLR-2 and TLR-4 play an important role in innate immunity by recognizing envelope proteins of MV. Another important cytokine that plays an important role in orchestrating innate immune function is IL-17. The purpose of our study is to elucidate whether the TLR2, TLR4, IL17F and IL17A gene polymorphisms are susceptibility genes for the development of SSPE.Using the PCR-RFLP methods, the single nucleotide polymorphisms of TLR2 ( ...Daha fazlası

Makale 2014 Gene547 ( 2 ) , pp. 1 - 190 458 Görüntülenme

Genesis and geodynamic significance of chromitites from the Orhaneli and Harmancik ophiolites (Bursa, NW Turkey) as evidenced by mineralogical and compositional data

Uysal I. | Akmaz R.M. | Kapsiotis A. | Demir Y. | Saka S. | Avci E. | Müller D.

Chromitites from Orhaneli and Harmancik ophiolites (Bursa, NW Turkey) are mainly associated with dunites. They occur as banded and lenticular bodies showing massive and disseminated textures and are composed of magnesiochromite grains characterized by the following composition: Cr2O3=58.30-61.19wt.%, Al2O3=8.32-10.03wt.% and TiO2=0.14-0.21wt.%. The Cr# [Cr/(Cr+Al)] values of magnesiochromite from both ophiolites range between 0.80 and 0.83 and their Mg# [Mg/(Mg+Fe2+)] values vary from 0.52 to 0.69. However, one chromitite sample (BO13B) from the Orhaneli ophiolite contains magnesiochromite wit ...Daha fazlası

Makale 2015 Ore Geology Reviews65 ( P1 ) , pp. 2 - 41 356 Görüntülenme

Influence of an external magnetic field on the current-voltage characteristics and transport critical current density

Kiliç A. | Kiliç K. | Senoussi S. | Demir K.

The influence of the external field on the current-voltage characteristics and the critical current density Jc and on the angular dependence of voltage V and resistivity ? have been discussed in terms of the Lorentz force driven flux flow motion of the vortices. We have obtained analytical expressions for the field dependencies and angular dependencies of the critical current density, the current-voltage characteristics, voltage V and resistivity ? which are in reasonable agreement with the experimental data published previously. © 1998 Elsevier Science B.V.

Makale 1998 Physica C: Superconductivity and its Applications294 ( 03.Apr ) , pp. 2 - 216 393 Görüntülenme

Investigation on the levitation force behaviour of malic acid added bulk MgB2 superconductors

Savaskan B. | Taylan Koparan E. | Celik S. | Ozturk K. | Yanmaz E.

The effects of malic acid addition (from 0 to 15 wt% of the total MgB 2) on the levitation force properties of bulk MgB2 have been investigated. All samples were prepared from magnesium powder, amorphous boron powder, malic acid (C4H6O5) and toluene (C7H8) by using two-step solid state reaction method. Vertical and lateral levitation force measurements that are under both zero-field-cooled (ZFC) and field-cooled (FC) regimes were carried out at different temperatures of 24, 28 and 32 K for samples with various adding level. It was found that the reasonable malic acid adding has a positive impa ...Daha fazlası

Makale 2014 Physica C: Superconductivity and its Applications502 , pp. 6 - 69 475 Görüntülenme

Detaylı Arama

Filtreler

Koleksiyon [16]

İlgili Araştırmacılar [30]

Ambargo Durumu [1]

Tam Metin [2]

Yazar [90]

Yayın Türü [3]

Yayın Yılı [12]

Yayın Dili [1]

Dergi Adı [41]

Yayıncı [1]

Konu Başlıkları [90]