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Poly(OEGMA)-B Block Copolymer Nanocarriers for Anticancer Agent Release
(Wiley, 01.06.2018) Aksit, N. N.; Topuzogullari, M.; Isoglu, I. A.; El Khatib, M.; Isoglu, S. Dincer; 0000-0002-8697-1654; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; 01. Abdullah Gül University; 04. Yaşam ve Doğa Bilimleri Fakültesi; 04.01. Biyomühendislik
A New Method to Identify Affected Pathway Subnetworks and Clusters in Colon Cancer
(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 11092019) Goy, Gokhan; Yazici, Miray Unlu; Bakir-Gungor, Buren; AGÜ, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü; 01. Abdullah Gül University; 04. Yaşam ve Doğa Bilimleri Fakültesi; 04.01. Biyomühendislik
Nowadays new technological developments that play an important role in the production of big data have brought about the interpretation, sharing and storage of data related to complex diseases. Combining multi-omic data in different molecular levels is potentially important for understanding the biological origin of complex diseases. One of these complex diseases is cancer of different types, which has one of the highest causes of death worldwide. The integration of multiple omic data in the framework of a comprehensive analysis and identification of relevant pathways contribute to the development of therapeutic approaches related to disease. In this study, RNA and methylation data (genes and p values) of colon adenocarcinoma were obtained from TCGA data portal and combined with Fisher's method. While protein subnetworks affected by the disease were identified by using subnetwork algorithm, pathways related to the disease and genes associated with these pathways were determined by functional enrichment analysis. Using gene-pathway relationship matrix, kappa scores of pathways were determined by similarity calculation. In this way, the pathways were clustered according to the hierarchically optimal number, as a result, the most important pathway clusters and related genes that are effective in disease formation identified.
Citation - WoS: 4
Citation - Scopus: 5
Analysis of Coronary Angiography Related Psychophysiological Responses
(BMC, 2011) Okkesim, Sukru; Kara, Sadik; Kaya, Mehmet G.; Asyali, Musa H.; 01. Abdullah Gül University
Background: Coronary angiography is an important tool in diagnosis of cardiovascular diseases. However, it is the administration is relatively stressful and emotionally traumatic for the subjects. The aim of this study is to evaluate psychophysiological responses induced by the coronary angiography instead of subjective methods such as a questionnaire. We have also evaluated the influence of the tranquilizer on the psychophysiological responses. Methods: Electrocardiography (ECG), Blood Volume Pulse (BVP), and Galvanic Skin Response (GSR) of 34 patients who underwent coronary angiography operation were recorded. Recordings were done at three phases: "1 hour before," "during," and "1 hour after" the coronary angiography test. Total of 5 features obtained from the physiological signals were compared across these three phases. Sixteen of the patients were administered 5 mg of a tranquilizer (Diazepam) before the operation and remaining 18 were not. Results: Our results indicate that there is a strong correlation between features (LF/HF, Bk, DN1/DN2, skin conductance level and seg_mean) in terms of reflecting psychophysiological responses. However only DN1/DN2 feature has statistically significant differences between angiography phases (for diazepam: p = 0.0201, for non_diazepam p = 0.0224). We also note that there are statistically significant differences between the diazepam and non-diazepam groups for seg_mean features in "before", "during" and "after" phases (p = 0.0156, 0.0282, and 0.0443, respectively). Conclusions: The most intense sympathetic activity is observed in the "during" angiography phase for both of the groups. The obtained features can be used in some clinical studies where generation of the customized/individual diagnoses styles and quantitative evaluation of psychophysiological responses is necessary.
Citation - WoS: 6
Citation - Scopus: 8
The Effects of Different Types of Fly Ash on the Compressive Strength Properties of Briquettes
(Hindawi Ltd, 2011) Sola, Ozlem Celik; Yayla, Murat; Sayin, Baris; Atis, Cengiz Duran; 01. Abdullah Gül University
The aim of this study is to evaluate the effect of the different types of fly ash on the compressive strength properties of sintered briquettes. Thermal gravimetric (TG) analysis was carried out. The chemical composition and physical properties of the materials used were determined. Particle size distribution and microstructure elemental analyses of the materials used were carried out by a particle size analyzer (Mastersizer) and a scanning electron microscope (SEM-EDS). Following the characterization of the materials, briquettes were prepared by sintering at different temperatures. Compressive strength test results of the briquette samples indicated that briquettes with a compressive strength value of 47.45 N/mm(2) can be produced. The results obtained exceed the Turkish standard (TS EN 771-1) requirements (9.8-23.54 N/mm(2)). SEM-EDS results showed that briquette samples made with Tuncbilek (T) fly ash had a higher percentage of the glassy phase than the other briquette samples. Due to this microstructure, it results in higher compressive strength value.
Citation - WoS: 13
Design and Implementation of a Voice-Controlled Prosthetic Hand
(Tubitak Scientific & Technological Research Council Turkey, 2011) Asyali, Musa Hakan; Yilmaz, Mustafa; Tokmakci, Mahmut; Sedef, Kanber; Aksebzeci, Bekir Hakan; Mittal, Rohin; 01. Abdullah Gül University
Current hand prostheses are mostly driven by electromyography (EMG) signal, and existing experiments have proved that multichannel EMG signal controls are not suitable due to early fatigue problems and high effort, requirements to perform even simple activities. Therefore, in this study we present a new voice-controlled active hand prosthesis to perform several basic tasks. We first designed a novel multifingered prosthetic hand with the ability of picking up and releasing objects. The prosthetic hand employs 3 DC motors and gears to transfer motion to the linked parts of the fingers. We used flexible thin-film, resistive force sensors at the fingertips of the prosthetic hand to adjust the grip force at the fingers. The second part of the study involves the use of speech recognition to control the prosthetic hand. The control circuit that we designed consisted of an HM2007 speech recognition IC and a PIC microcontroller to drive the DC motors moving the fingers. We implemented both the prosthetic hand and its speech recognition-based control electronics. As of now, we have programmed the control hardware to recognize simple pick up and release operations and have successfully tested them. In a future study, we will include more voice commands for the operation of the hand, such as a realistic handshake, and improve the cosmetics of the hand in order to make it look more natural.
Citation - WoS: 76
Citation - Scopus: 91
Effect of Granulated Blast Furnace Slag and Fly Ash Addition on the Strength Properties of Lightweight Mortars Containing Waste PET Aggregates
(Elsevier Sci Ltd, 2011) Akcaozoglu, Semiha; Atis, Cengiz Duran; 01. Abdullah Gül University
In this work, the effect of Granulated Blast Furnace Slag (GBFS) and fly ash (FA) addition on the strength properties of lightweight mortars containing waste Poly-ethylene Terephthalate (PET) bottle aggregates was investigated. Investigation was carried out on three groups of mortar specimens. One made with only Normal Portland cement (NPC) as binder, second made with NPC and GBFS together and, third made with NPC and FA together. The industrial wastes mentioned above were used as the replacement of cement on mass basis at the replacement ratio of 50%. The size of shredded PET granules used as aggregate for the preparation of mortar mixtures were between 0 and 4 mm. The waste lightweight PET aggregate (WPLA)-binder ratio (WPLA/b) was 0.60; the water-binder (w/b) ratios were determined as 0.45 and 0.50. The dry unit weight, compressive and flexural-tensile strengths, carbonation depths and drying shrinkage values were measured and presented. The results have shown that modifying GBFS had positive effects on the compressive strength and drying shrinkage values (after 90 days) of the WPLA mortars. However, FA substitution decreased compressive and flexural-tensile strengths and increased carbonation depths. Nevertheless a visible reduction occurred on the drying shrinkage values of FA modifying specimens more than cement specimens and GBFS modified specimens. The test results indicated that, GBFS has a potential of using as the replacement of cement on the WPLA mortars by taking into consideration the characteristics. But using FA as a binder at the replacement ratio of 50% did not improve the overall strength properties. Although it was thought that, using FA as binder at the replacement ratio of 50% for the aim of production WPLA concrete which has a specific strength, would provide advantages of economical and ecological aspects. (C) 2011 Elsevier Ltd. All rights reserved.
Citation - Scopus: 2
Dissolution of Mixed Zinc-Carbon and Alkaline Battery Powders in Sulphuric Acid Using Ascorbic/Oxalic Acid as a Reductant
(Minerals, Metals and Materials Society 184 Thorn Hill Road Warrendale PA 15086, 2012) Kaya, Muammer; Kursunoglu, Sait; 01. Abdullah Gül University
The aim of this study was to investigate the effectiveness of ascorbic (C6H8O6) / oxalic (C2H 2O4) acid as a reductant for the simultaneous recovery of zinc and manganese from a spent and mixed zinc-carbon and alkaline battery powder in sulphuric acid leaching. The effects of sulfuric acid concentration, ascorbic/oxalic acid dosages, reaction temperature and leaching time on the zinc and manganese dissolutions were investigated according to 2k full factorial experimental design; then, a simple optimization study was carried out for the best reductant. The optimum reductive acid leaching conditions were determined at 3 hours leaching time, 70°C leaching temperature, 0.5M sulfuric acid concentration, 13 g/L ascorbic acid dosage, 1/20 g/mL solid/liquid ratio and 200 rpm stirring speed. Under these conditions, the dissolution efficiencies were 99.9% for Zn and 99.3% for Mn. When our results were compared with the previous results, our findings were better than previous studies. In addition, the manganese dissolution kinetics was undertaken, and the activation energy was found to be 7.04 kJ/mol. Selective precipitations of Zn and Mn from acid solutions were carried out using NaOH and KOH. Using 3M NaOH as precipitating agent at room temperature and at pH 8; 95.4% of Zn and at pH 10; 93.7% of Mn were precipitated from the leaching solution. Under the same conditions, using 3 M KOH at pH 8; 91.6% of Zn and at pH 10, 96.4% of Mn were precipitated. Based on the experimental results obtained, an appropriate flow sheet was proposed to recover zinc and manganese. © 2020 Elsevier B.V., All rights reserved.
Citation - WoS: 13
The Role of Spatial Planning for Sustainable Tourism Development: A Theoretical Model for Turkey
(Inst Tourism, 2012) Dede, Okan Murat; Ayten, Asim Mustafa; 01. Abdullah Gül University; 05. Mimarlık Fakültesi
Planning concept is an important concept for realizing the benefits of the tourism sector for localities, public and environment. Planning is a broad term covering several stages from national strategic decisions to unique design applications. Spatial planning is an important aspect of planning with a focus on physical planning in various sectors as well as tourism. The importance of planning has increased with the prominence of a second concept; sustainability. Since the 1970' s, sustainability has continuously gained importance in all socio economic aspects of human beings. It is also important for the tourism sector as this sector has effects on the environment. This article tackles the role and importance of physical planning for the development of sustainable tourism concept. For this reason, a model is built for sustainable tourism development in Turkey as Turkish legislation system regarding planning and tourism should be improved in terms of sustainability. The aim of the article is to determine how to integrate spatial planning to sustainable tourism development and to decide the possible pathways within sustainable tourism development. The model considers all stages from large scale decisions to architectural design within a comprehensive manner. This model could be utilized to deal with all aspects of planning, such as policies, strategies, spatial decisions, building structuring, density, site planning and architecture.
Citation - WoS: 19
Citation - Scopus: 36
Fresh, Mechanical, Transport, and Durability Properties of Self-Consolidating Rubberized Concrete
(Amer Concrete inst, 2012) Karahan, Okan; Ozbay, Erdogan; Hossain, Khandaker M. A.; Lachemi, Mohamed; Atis, Cengiz D.; 01. Abdullah Gül University
This paper presents the fresh, mechanical, transport, and durability performances of self-consolidating rubberized concretes (SCRCs). Fresh concrete properties were determined with slump flow, V-funnel, J-ring, and L-box tests. Mechanical, transport, and durability properties were determined by measuring compressive, flexural, and splitting tensile strengths; bond strength characteristics; water porosity; water absorption; water sorptivity; rapid chloride-ion permeability; and freezing-and-thawing and corrosion resistance. SCRC mixtures with a water-binder ratio (w/b) of 0.32; total binder content of 500 kg/m(3) (842 lb/yd(3)); and crumb rubber content of 0, 10, 20, and 30% by fine aggregate volume were produced and tested. Fresh properties testing revealed that the use of crumb rubber as a fine aggregate diminished the filling and passing ability of SCRC. A gradual reduction in mechanical properties was also observed with an increase in crumb rubber content; however, the rate of compressive strength reduction was more evident than that of tensile strength. Despite the fact that water porosity, water absorption, and chloride-ion permeability increased slightly with the use of crumb rubber, a remarkable decrease was observed in the initial and secondary water sorptivity of SCRC. No significant decrease was observed in the freezing-and-thawing and corrosion resistance of SCRC with 10% crumb rubber. Beyond that level, however, durability performance was significantly affected.
Citation - WoS: 11
Citation - Scopus: 12
The Effect of Dilute Nitrogen on Nonlinear Optical Properties of the IngaAsN/GaAs Single Quantum Wells
(Springer, 2012) Koksal, K.; Sahin, M.; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
In this study, we investigate the linear and third order nonlinear optical properties of InGaAsN/GaAs depending on nitrogen content and laser dressing parameter. As theoretical models, band anticrossing and model solid theory are used. In order to obtain the electronic properties of the quantum well, the finite difference method is used. The laser beam affects the electronic properties of the quantum well by changing the shape of the confinement potential. This modification of the potential is determined by laser dressing parameter. By using dilute amount of nitrogen, conduction band and the depth of quantum well can be controlled. The strain which is introduced due to the presence of nitrogen can be compensated by using indium atoms. The electronic and the linear and third order nonlinear optical properties of InGaAsN/GaAs quantum well structure are obtained.
Citation - WoS: 35
Citation - Scopus: 40
The Photoionization Cross Section of a Hydrogenic Impurity in a Multi-Layered Spherical Quantum Dot
(Amer Inst Physics, 2012) Sahin, Mehmet; Tek, Firdes; Erdinc, Ahmet; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
In this study, we have investigated the photoionization cross section of an on-center hydrogenic impurity in a multi-layered spherical quantum dot. The electronic energy levels and their wave functions have been determined fully numerically by shooting method. Also, we have calculated the binding energy of the impurity by using these energy values. The photoionization cross section has also been computed as a function of the layer thickness and normalized photon energies. We have discussed in detail the possible physical reasons behind the changes in the binding energies and photoionization cross section. It is observed that both the binding energies and the photoionization cross sections depend strongly on the layer thickness and photon energies. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705410]
Citation - WoS: 41
Citation - Scopus: 46
The Linear Optical Properties of a Multi-Shell Spherical Quantum Dot of a Parabolic Confinement for Cases With and Without a Hydrogenic Impurity
(IOP Publishing Ltd, 2012) Sahin, Mehmet; Koksal, Koray; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
Throughout this work, we aim to explore the linear optical properties of a semiconductor multi-shell spherical quantum dot with and without a hydrogenic donor impurity. The core and well layers are defined by the parabolic electronic potentials in the radial direction. The energy levels and corresponding wavefunctions of the structure are calculated by using the shooting technique in the framework of the effective-mass approximation. We investigate the intersublevel absorption coefficients of a single electron and the hydrogenic donor impurity comparatively as a function of the photon energy. In addition, we carry out the effect of a donor impurity and the layer thickness on the oscillator strengths and magnitude and position of absorption coefficient peaks. We illustrate the electron probability distribution and variation of the energy levels in cases with and without the impurity for different thicknesses of layers. This kind of structure gives an opportunity to tune and control the absorption coefficient of the system by changing three different thickness parameters. Also it provides a possibility to separate 0s and 1p electrons in different regions of the quantum dot.
Citation - WoS: 7
Citation - Scopus: 7
A New Per-Field Classification Method Using Mixture Discriminant Analysis
(Taylor & Francis Ltd, 2012) Calis, Nazif; Erol, Hamza; 01. Abdullah Gül University
In this study, a new per-field classification method is proposed for supervised classification of remotely sensed multispectral image data of an agricultural area using Gaussian mixture discriminant analysis (MDA). For the proposed per-field classification method, multivariate Gaussian mixture models constructed for control and test fields can have fixed or different number of components and each component can have different or common covariance matrix structure. The discrimination function and the decision rule of this method are established according to the average Bhattacharyya distance and the minimum values of the average Bhattacharyya distances, respectively. The proposed per-field classification method is analyzed for different structures of a covariance matrix with fixed and different number of components. Also, we classify the remotely sensed multispectral image data using the per-pixel classification method based on Gaussian MDA.
Citation - WoS: 80
Citation - Scopus: 90
Alkali Activation of Mortars Containing Different Replacement Levels of Ground Granulated Blast Furnace Slag
(Elsevier Sci Ltd, 2012) Bilim, Cahit; Atis, Cengiz Duran; 01. Abdullah Gül University
The aim of the present study is to investigate some properties of alkali-activated mortars containing slag at different replacement levels. Ground granulated blast furnace slag was used at 0%, 20%, 40%, 60%, 80% and 100% replacement by weight of cement, and liquid sodium silicate having three different Na dosages was chosen as the alkaline activator. In this research, carbonation resistance measurements and compressive and flexural strength tests were performed on the mortar specimens with size of 40 x 40 x 160 mm. The findings obtained from the tests showed that carbonation depth values of the mortars decreased with the increase of activator dosage. Additionally, compressive and flexural strength values increased with the increase in activator concentration and slag replacement level. Portland cement/slag mortars activated by liquid sodium silicate exhibited lower strength than the slag alone activated by the same activator. (C) 2011 Elsevier Ltd. All rights reserved.
Citation - Scopus: 13
Staging of the Liver Fibrosis From CT Images Using Texture Features
(2012) Kayaaltı, Ömer; Aksebzeci, Bekir Hakan; Karahan, Ökkeş Ibrahim; Deniz, Kemal; Öztürk, Menmet; Yilmaz, Bulent; Asyali, Musa Hakan; 0000-0003-2954-1217; 0000-0001-7476-8141; AGÜ; Aksebzeci, Bekir Hakan; Yilmaz, Bülent; Asyali, Musa Hakan; 01. Abdullah Gül University
Even though liver biopsy is critical for evaluating chronic hepatitis and fibrosis, it is an invasive, costly, and difficult to standardize approach. The developments in medical image processing and artificial intelligence methods have advanced the potential of using computer-aided diagnosis techniques in the classification of liver tissues. The aim of this study was to develop a non-invasive, cost-effective, and fast approach to specify fibrosis stage using the texture properties of computed tomography images of liver. Gray level co-occurrence matrix, discrete wavelet transform, and discrete Fourier transform were the image analysis tools in the feature extraction phase. Following dimension reduction of the texture features support vector machines and k-nearest neighbor methods were used in the classification phase of this study. Our results showed that our approach is feasible in fibrosis staging especially in pairwise stage comparisons with success rate of approximately 90%. © 2012 IEEE. © 2012 Elsevier B.V., All rights reserved.
Sosyal medyanın çok katlı pazarlamada kullanımı ve iş tatmini üzerindeki etkileri
(Bandırma Onyedi Eylül Üniversitesi, 2012) Emirza, Emin; İştahlı, Selma B.; İştahlı, Yusuf H.; AGÜ, Yönetim Bilimleri Fakültesi, İşletme Bölümü; İştahlı, Yusuf H.; 01. Abdullah Gül University
Kitle iletişim kanallarının bölünmüşlüğü ve reklam mesajlarının çokluğu, doğru hedef kitleye ulaşmayı ve mesajın müşteriler tarafından algılanmasını zorlaştırmaktadır. Bundan dolayı geleneksel medya kanallarında yapılan tutundurma çabaları sorgulanır hale gelirken, sosyal medya ortamları reklam, halkla ilişkiler vb. alanlarda etkili iletişim stratejilerinin üretilmesinde giderek daha fazla önem kazanmaya başlamıştır. Diğer taraftan sosyal medyanın sunduğu çevrimiçi olanaklarla, bireyi içerik üreten, paylaşan, tavsiye eden kısaca interaktif olarak pazarlama sürecini etkileyen aktörler haline getirmesi, satıcı-alıcı ilişkilerine dair paradigmaları değiştirmektedir. Bu potansiyelin ilk farkına varan ve iş süreçlerine uygulayan işletmelerin başında “çok katlı pazarlama” stratejisini kullanan işletmeler gelmektedir. Satış odaklı çok katlı pazarlama sisteminde, bağımsız girişimcilerin performanslarını etkileyen iş tatmin düzeylerinin yükseltilmesi, yeni müşteri ve bağımsız girişimciler kazanma açısından önemlidir. Sosyal medyanın, içerik üretmeye ve anlık etkileşime olanak sağlamasının bağımsız girişimcilerin iş tatminini olumlu etkilediği düşülmektedir. Bu varsayımdan hareketle çok katlı pazarlama stratejisini kullanan küresel bir işletmenin Türkiye’deki serbest girişimcilerinin sosyal medyayı kullanım biçimleri ve bunun iş tatmini üzerindeki etkileri incelenmiştir. Anket yöntemi kullanılarak yapılan araştırmada, serbest girişimcilerin sosyal medyayı, yüz yüze iletişim kadar önemsedikleri fakat iş amaçlı olarak kullanma konusunda yeterli motivasyona sahip olmadıkları gözlemlenmiştir. Bu gözlemi destekleyen regresyon analizlerinde, bağımsız girişimcilerin sosyal medya kullanım düzeylerinin, iş tatmini açıklamada etkili fakat zayıf bir etkiye sahip olduğu ortaya çıkmıştır. Korelasyon analizlerinde ise, sosyal medya kullanım düzeyi ile içsel iş tatmini, dışsal iş tatmini ve genel iş tatmini arasında pozitif doğrusal bir ilişki olduğu anlaşılmıştır.
Citation - WoS: 18
Citation - Scopus: 19
Infrared Multiple Photon Dissociation Spectroscopy of Protonated Histidine and 4-Phenylmidazole
(Elsevier, 2012) Citir, Murat; Hinton, Christopher S.; Oomens, Jos; Steill, Jeffrey D.; Armentrout, P. B.; 01. Abdullah Gül University
The gas-phase structures of protonated histidine (His) and the side-chain model, protonated 4-phenyl imidazole (PhIm), are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light generated by the free electron laser FELIX. To identify the structures present in the experimental studies, the measured IRMPD spectra are compared to spectra calculated at a B3LYP/6-311+G(d,p) level of theory. Relative energies of various conformers are provided by single point energy calculations carried out at the B3LYP, B3P86, and MP2(full) levels using the 6-311+G(2d,2p) basis set. On the basis of these experiments and calculations, the IRMPD action spectrum for H+(His) is characterized by a mixture of [N-pi,N-alpha] and [N-pi,CO] conformers, with the former dominating. These conformers have the protonated nitrogen atom of imidazole adjacent to the side-chain (N-pi) hydrogen bonding to the backbone amino nitrogen (N-alpha) and to the backbone carbonyl oxygen, respectively. Comparison of the present results to recent IRMPD studies of protonated histamine, the radical His(center dot+) cation, H+(HisArg), H-2(2+)(HisArg), and M+(His), where M+ = Li+, Na+, K+, Rb+, and Cs+, allows evaluation of the vibrational motions associated with the observed bands. (c) 2012 Elsevier B.V. All rights reserved.
Citation - WoS: 54
Citation - Scopus: 59
The Electronic Properties of a Core/Shell Spherical Quantum Dot With and Without a Hydrogenic Impurity
(Amer Inst Physics, 2012) Tas, Hatice; Sahin, Mehmet; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
In this study, we have performed a detailed investigation of the electronic properties of a core/shell/well/shell multilayered spherical quantum dot, such as energy eigenvalues, wave functions, electron probability distribution, and binding energies. The energy eigenvalues and their wave functions of the considered structure have been calculated for cases with and without an on-center impurity. For this purpose, the Schrodinger equation has been numerically solved by using the shooting method in the effective mass approximation for a finite confining potential. The electronic properties have been examined for different core radii, barrier thicknesses, and well widths in a certain potential. The results have been analyzed in detail as a function of the layer thicknesses and their physical reasons have been interpreted. It has been found that the electronic properties are strongly dependent on the layer thicknesses. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3702874]
Citation - WoS: 67
Citation - Scopus: 74
The Inter-Sublevel Optical Properties of a Spherical Quantum Dot-Quantum Well With and Without a Donor Impurity
(Amer Inst Physics, 2012) Tas, Hatice; Sahin, Mehmet; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
In this study, we have investigated the inter-sublevel optical properties of a core/shell/well/shell spherical quantum dot (QD) with the form of quantum dot-quantum well heterostructure. In order to determine the energy eigenvalues and corresponding wave functions, the Schrodinger equation has been solved full numerically by using shooting method in the effective mass approximation for a finite confining potential. The inter-sublevel optical absorption and the oscillator strength between ground (1 s) and excited (1 p) states have been examined based on the computed energies and wave functions. Also, the effect of a hydrogenic donor impurity, located at the center of the multi-shell spherical quantum dot (MSQD), has been researched for different core radii (R-1), shell thicknesses (T-s), and well widths (T-w) in certain potential. It is observed that the oscillator strengths and the absorption coefficients are strongly depend on the core radii and layer thicknesses of the MSQD. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751483]
Citation - Scopus: 30
Thermochemistry of Alkali Metal Cation Interactions With Histidine: Influence of the Side Chain
(2012) Armentrout, Peter B.; Citir, Murat; Chen, Yu; Rodgers, Mary T.; 01. Abdullah Gül University
The interactions of alkali metal cations (M+ = Na+, K+, Rb+, Cs+) with the amino acid histidine (His) are examined in detail. Experimentally, bond energies are determined using threshold collision-induced dissociation of the M+(His) complexes with xenon in a guided ion beam tandem mass spectrometer. Analyses of the energy dependent cross sections provide 0 K bond energies of 2.31 ± 0.11, 1.70 ± 0.08, 1.42 ± 0.06, and 1.22 ± 0.06 eV for complexes of His with Na+, K+, Rb+, and Cs+, respectively. All bond dissociation energy (BDE) determinations include consideration of unimolecular decay rates, internal energy of reactant ions, and multiple ion-neutral collisions. These experimental results are compared to values obtained from quantum chemical calculations conducted previously at the MP2(full)/6-311+G(2d,2p), B3LYP/6-311+G(2d,2p), and B3P86/6-311+G(2d,2p) levels with geometries and zero point energies calculated at the B3LYP/6-311+G(d,p) level where Rb and Cs use the Hay-Wadt effective core potential and basis set augmented with additional polarization functions (HW*). Additional calculations using the def2-TZVPPD basis set with B3LYP geometries were conducted here at all three levels of theory. Either basis set yields similar results for Na+(His) and K+(His), which are in reasonable agreement with the experimental BDEs. For Rb+(His) and Cs +(His), the HW* basis set and ECP underestimate the experimental BDEs, whereas the def2-TZVPPD basis set yields results in good agreement. The effect of the imidazole side chain on the BDEs is examined by comparing the present results with previous thermochemistry for other amino acids. Both polarizability and the local dipole moment of the side chain are influential in the energetics. © 2012 American Chemical Society. © 2013 Elsevier B.V., All rights reserved.; MEDLINE® is the source for the MeSH terms of this document.

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