RADIUS ESTIMATES OF CERTAIN ANALYTIC FUNCTIONS

( Sushil Kumar Pratima Rai ),( Asena C. Etinkaya ) 호남수학회 2021 호남수학학술지 Vol.43 No.4

Numerical techniques are used to determine the radius of convexity of the starlike functions related to cardioid shaped bounded domain. In addition, radius constants of certain starlikeness associated with right half plane of various starlike functions are computed.

BOUND ON HANKEL DETERMINANTS H^(2)_4(f) AND H^(3)_4(f) FOR LEMNISCATE STARLIKE FUNCTIONS

Asena Çetinkaya,Sushil Kumar,Pratima Rai 호남수학회 2023 호남수학학술지 Vol.45 No.1

We determine the upper bounds on fourth order Hankel determinants H^(2)_4(f) and H^(3)_4(f) for the class S ∗ L of lemniscate starlike functions defined on the open unit disk which was introduced by Sokol and Stankiewicz in [17].

Photovoltaic characteristics of Au/PVA (Bi-doped)/n-Si Schottky barrier diodes(SBDs) at various temperatures

H.G. Çetinkaya,H. Tecimer,H. Uslu,S. Altındal 한국물리학회 2013 Current Applied Physics Vol.13 No.6

The charge conduction properties of the Au/PVA (Bi-doped)/n-Si Schottky barrier diodes (SBDs) were investigated using currentevoltageetemperature (IeVeT) measurements in dark and under various illumination levels. For this purpose, the main diode parameters such as reverse-saturation current (Io),zero-bias barrier height (FBo), ideality factor (n), series resistance (Rs) and shunt resistance (Rsh) of diode were obtained as function of temperature and illumination level. Experimental results show that all of these electrical parameters are strong functions of illumination and temperature. The change in all electrical parameters becomes more important at low temperatures and illumination levels. While the n value decreases with increasing temperature and illumination level, FBo value increases. The fill factor (FF = Vm·Im/Voc·Isc) values were obtained as 0.34 at 80 K and 0.40 at 320 K under 50 Wand these values are near to a photodiode. Therefore, the fabricated diode can be used as a photodiode in optoelectronic applications. The forward bias IeV characteristics of the diode have also been explained by the space charge limited current (SCLC) model.

Preparation of poly(2-ethyl aniline)/kaolinite composite materials and investigation of their properties

Duygu Anaklı,Sevil Çetinkaya 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Conductive poly(2-ethyl aniline) (PEAn)/kaolinite composite was prepared by chemical polymerization in aqueous HCl medium in the presence of kaolinite particles by using potassium chromate (K2CrO4) as oxidant. Effects of polymerization conditions, such as concentrations of oxidant and 2-ethyl aniline, polymerization time and temperature on PEAn content and conductivity of composite, were investigated. The prepared composite material, having the highest PEAn content and conductivity, was obtained in the polymerization carried out at 20 ℃ for 2 h with 0.2 M K2CrO4 and 0.2 M EAn. It was observed that the micro-hardness of prepared composites increased with the increase in the PEAn contents of composites. The highest micro-hardness value of 7.92 kg mm-2 was reached at 24.6% PEAn content. Characterization of composites was carried out by FTIR spectroscopy, XRD, TGA and SEM techniques.

Some properties for spirallike functions involving generalized q-integral operator

Şahsene Altınkaya,Asena Çetinkaya 호남수학회 2023 호남수학학술지 Vol.45 No.4

In this note, we establish a new subfamily of spirallike functions by making use of a generalized q-integral operator. We examine characterization rule for functions which are member of this subclass. We further obtain coefficient estimate, subordination results and integral mean inequalities for functions in this class. The Fekete-Szeg¨o inequalities are also derived.

Effi cacy of the Combination of Tetracycline, Amoxicillin, and Lansoprazole in the Eradication of Helicobacter pylori in Treatment-Naïve Patients and in Patients Who Are Not Responsive to Clarithromycin-Based Regimens: A Pilot Study

Mesut Sezikli,Züleyha Akkan Çetinkaya,Fatih Güzelbulut,Atakan Yeşil,Mustafa Erhan Altınöz,Nuriye Ulu,Ayşe Oya Övünç Kurdaş 거트앤리버 소화기연관학회협의회 2012 Gut and Liver Vol.6 No.1

Background/Aims: The aim of this study was to evaluate the eradication rate of a triple therapy regimen that included a proton pump inhibitor, amoxicillin, and tetracycline instead of clarithromycin in treatment-naïve patients and in patients who did not respond to standard triple therapy. Methods: This study included 110 patients infected with Helicobacter pylori. Patients in groups A and B were treatment-naïve, and those in group C were not responsive to previous standard triple therapy. Patients in group A (n=40) received lansoprazole 30 mg b.i.d., amoxicillin 1,000 mg b.i.d., and clarithromycin 500 mg b.i.d. for 14 days. Patients in groups B (n=40) and C (n=30) received lansoprazole 30 mg b.i.d., amoxicillin 1,000 mg b.i.d., and tetracycline 500 mg q.i.d. for 14 days. Results: In group A, eradication was achieved in 18 (45%) of the 40 patients included in the intention-to-treat (ITT) analysis and in 18 (47.4%) of the 38 patients included in the per-protocol (PP) analysis. In group B, eradication was achieved in 15 (37.5%) of the 40 patients included in the ITT analysis and in 15 (39.3%) of the 38 patients included in the PP analysis. In group C, eradication was achieved in 14 (46.6%) of the 30 patients included in the ITT analysis and in 14 (43.8%) of the 29 patients included in the PP analysis. There was no statistically signifi cant difference among the 3 groups with regard to eradication rates (p>0.05). Conclusions: Despite the low rate of resistance to tetracycline, the combination of lansoprazole, amoxicillin, and tetracycline instead of clarithromycin is not a good option for the eradication of H. pylori.

Effect of a Mediterranean-style diet on the exercise performance and lactate elimination on adolescent athletes

Helvacı Gizem,Uçar Aslı,Çelebi Mehmet Mesut,Çetinkaya Haydar,Gündüz Ayşe Zülal 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.4

BACKGROUND/OBJECTIVES: Mediterranean diet is an environmentally friendly and healthy diet model. The diet offers many vegetables, fruits, nuts, and olive oil to consumers. In addition, it provides moderate amounts of fish and chicken, smaller quantities of dair y products, red meat, and processed meat. The Mediterranean diet has a high anti- inflammator y and antioxidant content, and it causes many physiological changes that can provide a physical performance advantage. This study examined the effects of a 15-day menu, which was planned using foods with a low acid load within the Mediterranean diet rules, on the exercise performance, lactate elimination, anthropometric measurements, and body composition. SUBJECTS/METHODS: Fifteen professional male athletes between the ages of 13 and 18, who were engaged in ski running, were included in the experimental study. Dietar y inter vention was applied for 15 days. The athlete performances were evaluated by applying the vertical jump test, hand grip strength, 20 meters shuttle run test, and Borg fatigue scale. After the shuttle run test (ever y 3 min for 30 min), blood was drawn from the finger, and the lactate elimination time was calculated. Performance and lactate measurements, body analysis, and anthropometric measurements were taken before and after dietar y inter vention. RESULTS: The vertical jump height and hand grip strength increased after the inter vention (P < 0.05). The test duration, total distance, the number of shuttles, and maximum oxygen consumption parameters of the shuttle run test increased (P < 0.05). After the inter vention, the athletes’ perceived fatigue scores decreased in several stages of the shuttle run test (P < 0.05). The lactate elimination time and athlete’s body composition were similar in repeated measurements (P > 0.05). In the last measurements, the upper middle arm circumference decreased while the height of the athletes increased (P < 0.05). CONCLUSIONS: These results show that the Mediterranean diet is a safe and feasible dietar y approach for aerobic performance and strength increase.

Preparation of magnetic activated carbon-chitosan nanocomposite for crystal violet adsorption

Ferda Civan Çavuşoğlu,Seher Akan,Ezgi Aleyna Arı,Ezgi Çetinkaya,Elif Çolak,Gamze Nur Daştan,Semina Deniz,Damla Erdem,Melda Köksal,Sevgi Korkmaz,Nursena Onsekiz,Betül Oruçoğlu,Didem Özkaya,Hamdi Buğra 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11

Magnetic, cheap and versatile adsorbents were developed for crystal violet (CV) adsorption in this study. These adsorbents are magnetic activated carbon (AC-Fe3O4) and chitosan grafted magnetic activated carbon (Chitosan- AC-Fe3O4). Fe3O4 and chitosan were also used for adsorption. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), zeta potential analysis and Fourier transform infrared spectroscopy (FTIR) methods were used for characterization of adsorbents. Adsorption parameters for CV were investigated. Raw chitosan and Fe3O4 were also used for CV adsorption to compare the results of composites. The chosen adsorption parameters are amount of adsorbent, contact time, initial CV concentration, and temperature. The equilibrium period was observed to be very short for chitosan and Fe3O4 nanoparticles. The adsorption efficiencies of these adsorbents are very low. AC-Fe3O4 and AC-Fe3O4-Chitosan nanoparticles reached equilibrium at 80min. The all adsorbent-CV systems followed pseudo second-order kinetic model. AC-Fe3O4 and AC-Fe3O4-Chitosan composites suited non-linear Freundlich isotherm for all temperatures (298, 308 and 318 K). Regeneration of adsorbents was also investigated. 1M of acetic acid and 0.1M of NaOH solutions were tested. Acetic acid solution desorbed CV better than NaOH solution at 6 hours.

Evaluating the effect of donor anxiety levels and lifestyle characteristics on the activation of platelet concentrates

Soner Yılmaz,İbrahim Eker,Elif Elçi,Aysel Pekel,Rıza Aytaç Çetinkaya,Aytekin Ünlü,Cengizhan Açıkel,İsmail Yaşar Avcı 대한혈액학회 2019 Blood Research Vol.54 No.4

BackgroundSmoking, alcohol use, performing regular physical exercise, dietary habits, and anxiety level may cause platelet activation. We aimed to evaluate the anxiety levels, smoking sta-tus, alcohol intake, and sportive habits of donors, and determine their impact on the qual-ity of apheresis-platelets.MethodsState and Transient Anxiety Inventory (STAI) was used to determine the level of donors’anxiety. STAI has two subscales: S-anxiety scale (STAI-I) and T-anxiety scale (STAI-II), each comprising 20 questions rated on a 4-point Likert scale. Data on smoking, alcohol con-sumption, and performing regular physical exercise were obtained from a questionnaire filled out before donation. Flow cytometric analysis was used to quantify activated platelets.ResultsThe STAI-I level of 86 participants was normal, while that of 12 was higher. No significant difference was found in the active platelet absolute count [1.8×1011 (2.7) and 1.4×1011 (1.3), respectively; P=0.665] between donors with normal STAI-I levels and those with higher STAI-I levels. Of 98 donors, 42 had normal STAI-II levels, while 56 had higher STAI-II levels. No significant difference was found in the active platelet absolute count [2.3×1011 (3.1) and 1.5×1011 (2.3), respectively; P=0.224] between donors with normal STAI-II levels and those with higher STAI-II levels. Platelet counts of individuals who perform regular physical exercise were significantly higher than those of individuals who did not perform regular physical exercise (6.3±1.4×1011 vs. 5.5±1.4×1011).ConclusionThe quality of apheresis platelets is not affected by anxiety levels and lifestyle character-istics of blood donors. There is no need to organize apheresis blood donor pool consider-ing with these subjects.

Articular Cartilage Regeneration Utilizing Decellularized Human Placental Scaffold, Mesenchymal Stem Cells and Platelet Rich Plasma

Özdemir Erdi,Emet Abdülsamet,Hashemihesar Ramin,Yürüker Ali Celalettin Sinan,Kılıç Emine,Uçkan Çetinkaya Duygu,Turhan Egemen 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.6

Background: Articular cartilage repair has been a challenge in orthopedic practice due to the limited self-regenerative capability. Optimal treatment method for cartilage defects has not been defined. We investigated the effect of decellularized human placental (DHP) scaffold, mesenchymal stem cells (MSC) and platelet-rich plasma (PRP) on hyaline cartilage regeneration in a rat model. Methods: An osteochondral defect was created in trochlea region of the femur in all groups, bilaterally. No additional procedure was performed in control group (n = 14). Only the DHP scaffold was applied to the P group (n = 14). The DHP scaffold and 1 × 106 MSCs were applied to the PS group (n = 14). The DHP scaffold and PRP were applied to the PP group (n = 14). The DHP scaffold, 1 × 106 MSCs and PRP were applied to the PSP group (n = 14). Outcome measures at 12 weeks included Pineda histology score and qualitative histology. Results: The mean Pineda scores of P, PS, PP, and PSP groups were significantly better than the control group (p = 0.031, p = 0.002, p < 0.001, p < 0001, respectively). There was no statistically difference in mean Pineda scores of P, PS, PP, and PSP groups (p > 0.05). Conclusion: In conclusion, the DHP scaffold appears to be a promising scaffold on hyaline cartilage regeneration. The augmentation of DHP scaffold with MSCs and PRP combinations did not enhance its efficacy on articular cartilage regeneration.