Ultralow bandgap molecular semiconductors for ambient-stable and solution-processable ambipolar organic field-effect transistors and inverters

Ozdemir, Resul,Choi, Donghee,Ozdemir, Mehmet,Kwon, Guhyun,Kim, Hyekyoung,Sen, Unal,Kim, Choongik,Usta, Hakan The Royal Society of Chemistry 2017 Journal of Materials Chemistry C Vol.5 No.9

<P>The design and development of novel ambipolar semiconductors is very crucial to advance various optoelectronic technologies including organic complementary (CMOS) integrated circuits. Although numerous high-performance ambipolar polymers have been realized to date, small molecules have been unable to provide high ambipolar performance in combination with ambient-stability and solution-processibility. In this study, by implementing highly π-electron deficient, ladder-typeIFDK/IFDMacceptor cores with bithiophene donor units in D-A-D π-architectures, two novel small molecules,2OD-TTIFDKand2OD-TTIFDM, were designed, synthesized and characterized in order to achieve ultralow band-gap (1.21-1.65 eV) semiconductors with sufficiently balanced molecular energetics for ambipolarity. The HOMO/LUMO energies of the new semiconductors are found to be −5.47/−3.61 and −5.49/−4.23 eV, respectively. Bottom-gate/top-contact OFETs fabricated<I>via</I>solution-shearing of2OD-TTIFDMyield perfectly ambient stable ambipolar devices with reasonably balanced electron and hole mobilities of 0.13 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP>and 0.01 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP>, respectively with<I>I</I>on/<I>I</I>offratios of ∼10<SUP>3</SUP>-10<SUP>4</SUP>, and2OD-TTIFDK-based OFETs exhibit ambipolarity under vacuum with highly balanced (<I>μ</I>e/<I>μ</I>h∼ 2) electron and hole mobilities of 0.02 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP>and 0.01 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP>, respectively with<I>I</I>on/<I>I</I>offratios of ∼10<SUP>5</SUP>-10<SUP>6</SUP>. Furthermore, complementary-like inverter circuits were demonstrated with the current ambipolar semiconductors resulting in high voltage gains of up to 80. Our findings clearly indicate that ambient-stability of ambipolar semiconductors is a function of molecular orbital energetics without being directly related to a bulk π-backbone structure. To the best of our knowledge, considering the processing, charge-transport and inverter characteristics, the current semiconductors stand out among the best performing ambipolar small molecules in the OFET and CMOS-like circuit literature. Our results provide an efficient approach in designing ultralow band-gap ambipolar small molecules with good solution-processibility and ambient-stability for various optoelectronic technologies, including CMOS-like integrated circuits.</P>

ERCC1 Expression Does Not Predict Survival and Treatment Response in Advanced Stage Non-Small Cell Lung Cancer Cases Treated with Platinum Based Chemotherapy

Ozdemir, Ozer,Ozdemir, Pelin,Veral, Ali,Uluer, Hatice,Ozhan, Mustafa Hikmet Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Background: ERCC1 is considered as a promising molecular marker that may predict platinum based chemotherapy response in non small cell lung cancer patients. We therefore investigated whether its expression is indeed associated with clinical outcomes in advanced stage NSCLC patients. Materials and Methods: Pretreatment tumor biopsy samples of 83 stage 3B and 4 non-small cell lung cancer patients treated with platinum based chemotherapy were retrospectively analyzed for immunohistochemical ERCC1 expression. None of the patients received curative surgery or radiotherapy. Results: By calculating H- scores regarding the extent and intensity of immunohistochemical staining of tumor biopsy samples, ERCC1 expression was found to be positive in 50 patients (60.2%). ERCC1 positive and negative groups had no statistically significant differences regarding treatment response, progression free survival and overall survival (respectively p=0.161; p=0.412; p=0.823). Conclusions: In our study we found no association between ERCC1 expression and survival or treatment response. The study has some limitations, such as small sample size and retrospective analysis method. There is need of more knowledge for use of ERCC1 guided chemotherapy regimens in advanced stage NSCLC.

Possible Roles of the Xenobiotic Transporter P-glycoproteins Encoded by the MDR1 3435 C>T Gene Polymorphism in Differentiated Thyroid Cancers

Ozdemir, Semra,Uludag, Ahmet,Silan, Fatma,Atik, Sinem Yalcintepe,Turgut, Bulent,Ozdemir, Ozturk Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter which plays an important role in pharmacokinetics. The current preliminary study was designed to determine associations between a germ-line polymorphism in the MDR1 gene with differentiated thyroid carcinoma (DTC). Materials and Methods: In the current case-control study, 60 differentiated thyroid cancers (DTC)- 45 papillary TC (PTC), 9 follicular TC(FTC) and 6 well-differentiated tumors of uncertain malignant potential (WDT-UMP) were examined. Results were compared to a healthy control group (n=58) from the same population. Genomic DNA was extracted from peripheral blood with EDTA and the target gene was genotyped by real-time PCR. Results: Carriers of the variant allele of MDR1 exon 26 polymorphism were at 2.8-fold higher risk of DTC than the control group (odds ratio [OR]: 0.3805, 95% confidence interval [Cl]: 0.1597-0.9065 (p> 0.046). Conclusions: Presented results suggest that the MDR1 3435TT genotype might influence risk of development of DTC and that the CC genotype might be linked to a poor prognosis. Large-scale studies are now needed to validate this association.

The Role of Microaspiration in the Pathogenesis of Gastroesophageal Reflux-related Chronic Cough

( Pelin Ozdemir ),( Munevver Erdinc ),( Rukiye Vardar ),( Ali Veral ),( Serdar Akyildiz ),( Ozer Ozdemir ),( Serhat Bor ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2017 Journal of Neurogastroenterology and Motility (JNM Vol.23 No.1

Background/Aims Gastroesophageal reflux disease (GERD) is one of the main causes of chronic cough. We evaluated the role of microaspiration in the pathogenesis of reflux-related cough by determining the amount of lipid-laden macrophages (LLMs) in bronchoalveolar lavage (BAL) specimens. Methods A total of 161 cases of chronic cough were evaluated, and 36 patients (average age 48.2 years) were recruited for this single center prospective study. Patients with a history of smoking, angiotensin converting enzyme inhibitor usage, any abnormality on pulmonary function tests, abnormal chest X-rays, occupational or environmental exposures, or upper airway cough syndrome were excluded. GERD was evaluated by 24-hour esophageal impedance-pH monitoring. BAL specimens for LLM determination were obtained from 34 patients by flexible bronchoscopy. Results Patients with pathological intra-esophageal reflux according to multichannel intraluminal impedance and pH monitoring had higher LLM positivity in BAL specimens than patients without pathological reflux (8/14 in reflux positive group vs 1/22 in reflux negative group; P = 0.004). The BAL cell distribution was not different between the 2 groups (P = 0.574 for macrophages, P = 0.348 for lymphocytes, P = 0.873 for neutrophils and P = 0.450 for eosinophils). Conclusions Our results confirm the role of the microaspiration of refluxate in the pathogenetic mechanism of chronic cough. While bronchoscopy is indicated in patients with chronic cough, in addition to the routine airway evaluation, BAL and LLM detection should be performed. LLM can be used to diagnose aspiration in reflux-related chronic cough. Future studies are needed to evaluate the response to antireflux medications or surgery in patients with LLM positivity. (J Neurogastroenterol Motil 2017;23:41-48)

Can BAP1 expression loss in mesothelial cells be an indicator of malignancy?

Hanife Gulnihal Ozdemir,Sermin Coban Kokten,Nagehan Ozdemir Barisik 대한병리학회 2020 Journal of Pathology and Translational Medicine Vol.54 No.6

Background: Malignant mesothelioma is a highly aggressive tumor that can be confused with a benign mesothelial lesion, especially cytomorphologic lesions. BRCA1-associated protein 1 (BAP1) acts as a tumor suppressor. In this study, we aim to investigate the value of BAP1 staining of malignant mesothelioma cases with expression loss and diagnosis in cell block and biopsy tissue. Methods: Between January 2009 and March 2017, 64 mesotheliomas, 117 reactive mesothelial hyperplasias, and 20 fibrinous pleuritis/pericarditis were diagnosed with morphologic and immunohistochemical findings in our pathology clinic and were included in the study. Formalin-fixed, paraffin-embedded tissues were immunohistochemically examined for BAP1. Inflammatory and stromal cells were used as positive internal controls. BAP1 was assessed for nuclear staining in mesothelial cells. Results: Examinations of the relationship between patient diagnosis and BAP1 biopsy status showed that the BAP1 loss rate (76.6%) was significantly higher in malignant mesothelioma cases than in other benign diseases (0%) (p < .001). Sensitivity and specificity were 76.56% and 100%, respectively, for biopsy tissue from malignant mesothelioma. Sensitivity and specificity were both 100% for BAP1 test on cell block tissue. Furthermore, the consistency between BAP1 cell block and biopsy results was excellent (ĸ = 0.90) and the correlation was significant (p < .001). Conclusions: This study shows that BAP1 expression loss in both cytology and biopsy tissue in biopsy-confirmed malignant mesothelioma cases is an essential parameter for malignant mesothelioma diagnosis.

Videoendoscopic sentinel lymph node detection with icg and bilateral inguinofemoral lymphadenectomy in vulvar cancer comba-ozdemir technique

( Cihan Comba ),( Sakir Volkan Erdogan ),( Aliye Erdogan ),( Aysenur Bagdatli ),( Busra Seker Atas ),( Omer Demir ),( Isa Aykut Ozdemir ) 대한산부인과학회 2021 Obstetrics & Gynecology Science Vol.64 No.6

Objective The authors present a surgical film for vulvar cancer surgery, which was performed via video endoscopy. Methods An 88-yearold woman with squamous cell carcinoma of the vulva and who underwent radical vulvectomy was treated with sentinel lymph node (SLN) and bilateral inguinofemoral lymphadenectomy, which is preferably performed via video endoscopic surgery with a near-infrared fluorescence video endoscopy system. SLN mapping was performed using indocyanine green and near-infrared fluorescence mapping. Results SLNs were detected in the left superficial inguinal area. The surgeons performed bilateral inguinofemoral lymphadenectomy. Conclusion No postoperative early or late complications developed, and the patient was discharged 7 days after surgery. Stage 1B vulvar cancer was identified.

ON CHARACTERIZATIONS OF SOME LINEAR COMBINATIONS INVOLVING THE MATRICES Q AND R

Ozdemir, Halim,Karakaya, Sinan,Petik, Tugba The Honam Mathematical Society 2020 호남수학학술지 Vol.42 No.2

Let Q and R be the well-known matrices associated with Fibonacci and Lucas numbers, and k, m, and n be any integers. It is mainly established all solutions of the matrix equations c₁Qⁿ + c₂Q^m = Q^k, c₁Qⁿ + c₂Q^m = RQ^k, and c₁Qⁿ + c₂RQ^m = Q^k with unknowns c₁, c₂ ∈ ℂ*. Moreover, using the obtained results, it is presented many identities, some of them are available in the literature, and the others are new, related to the Fibonacci and Lucas numbers.

Is it shear locking or mesh refinement problem?

Ozdemir, Y.I.,Ayvaz, Y. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.2

Locking phenomenon is a mesh problem and can be staved off with mesh refinement. If the studier is not preferred going to the solution with increasing mesh size or the computer memory can stack over flow than using higher order plate finite element or using integration techniques is a solution for this problem. The purpose of this paper is to show the shear locking phenomenon can be avoided by increase low order finite element mesh size of the plates and to study shear locking-free analysis of thick plates using Mindlin's theory by using higher order displacement shape function and to determine the effects of various parameters such as the thickness/span ratio, mesh size on the linear responses of thick plates subjected to uniformly distributed loads. A computer program using finite element method is coded in C++ to analyze the plates clamped or simply supported along all four edges. In the analysis, 4-, 8- and 17-noded quadrilateral finite elements are used. It is concluded that 17-noded finite element converges to exact results much faster than 8-noded finite element, and that it is better to use 17-noded finite element for shear-locking free analysis of plates.

Orthodontic bonding to acid- or laser-etched prebleached enamel

Ozdemir, Fulya,Cakan, Umut,Gonul, Nese,Cakan, Derya Germec The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.3

Objective: Bonding forces of brackets to enamel surfaces may be affected by the procedures used for bleaching and enamel etching. The aim of this study was to investigate the bonding strength of orthodontic brackets to laser-etched surfaces of bleached teeth. Methods: In a nonbleached control group, acid etching (group A) or Er:YAG laser application (group B) was performed prior to bracket bonding (n = 13 in each group). Similar surface treatments were performed at 1 day (groups C and D; n = 13 in each subgroup) or at 3 weeks (groups E and F; n = 13 in each subgroup) after 38% hydrogen peroxide bleaching in another set of teeth. The specimens were debonded after thermocycling. Results: Laser etching of bleached teeth resulted in clinically unacceptable low bonding strength. In the case of acid-etched teeth, waiting for 3 weeks before attachment of brackets to the bleached surfaces resulted in similar, but not identical, bond strength values as those obtained with nonbleached surfaces. However, in the laser-etched groups, the bonding strength after 3 weeks was the same as that for the nonbleached group. Conclusions: When teeth bleached with 38% hydrogen peroxide are meant to be bonded immediately, acid etching is preferable.

Numerical study of ship motions and added resistance in regular incident waves of KVLCC2 model

Ozdemir, Yavuz Hakan,Barlas, Baris The Society of Naval Architects of Korea 2017 International Journal of Naval Architecture and Oc Vol.9 No.2

In this study, the numerical investigation of ship motions and added resistance at constant forward velocity of KVLCC2 model is presented. Finite volume CFD code is used to calculate three dimensional, incompressible, unsteady RANS equations. Numerical computations show that reliable numerical results can be obtained in head waves. In the numerical analyses, body attached mesh method is used to simulate the ship motions. Free surface is simulated by using VOF method. The relationship between the turbulence viscosity and the velocities are obtained through the standard ${\kappa}-{\varepsilon}$ turbulence model. The numerical results are examined in terms of ship resistance, ship motions and added resistance. The validation studies are carried out by comparing the present results obtained for the KVLCC2 hull from the literature. It is shown that, ship resistance, pitch and heave motions in regular head waves can be estimated accurately, although, added resistance can be predicted with some error.