Pubmed

Permanent URI for this collectionhttps://ada.atilim.edu.tr/handle/123456789/22

Browse

Now showing 1 - 20 of 74

Citation Count: 1
Adaptive Stimulus Design for Dynamic Recurrent Neural Network Models
(Frontiers Media Sa, 2019) Doruk, R. Ozgur; Zhang, Kechen; Electrical-Electronics Engineering
We present an adaptive stimulus design method for efficiently estimating the parameters of a dynamic recurrent network model with interacting excitatory and inhibitory neuronal populations. Although stimuli that are optimized for model parameter estimation should, in theory, have advantages over nonadaptive random stimuli, in practice it remains unclear in what way and to what extent an optimal design of time-varying stimuli may actually improve parameter estimation for this common type of recurrent network models. Here we specified the time course of each stimulus by a Fourier series whose amplitudes and phases were determined by maximizing a utility function based on the Fisher information matrix. To facilitate the optimization process, we have derived differential equations that govern the time evolution of the gradients of the utility function with respect to the stimulus parameters. The network parameters were estimated by maximum likelihood from the spike train data generated by an inhomogeneous Poisson process from the continuous network state. The adaptive design process was repeated in a closed loop, alternating between optimal stimulus design and parameter estimation from the updated stimulus-response data. Our results confirmed that, compared with random stimuli, optimally designed stimuli elicited responses with significantly better likelihood values for parameter estimation. Furthermore, all individual parameters, including the time constants and the connection weights, were recovered more accurately by the optimal design method. We also examined how the errors of different parameter estimates were correlated, and proposed heuristic formulas to account for the correlation patterns by an approximate parameter-confounding theory. Our results suggest that although adaptive optimal stimulus design incurs considerable computational cost even for the simplest excitatory-inhibitory recurrent network model, it may potentially help save time in experiments by reducing the number of stimuli needed for network parameter estimation.
Citation Count: 1
Analyzing two decades of intimate partner femicide-suicides in T?rkiye*
(Elsevier Sci Ltd, 2023) Cavlak, Mehmet; Odabasi, Aysun Balseven; Mutlu, Niluefer Dilara Ar; Erbaydar, Nueket Paksoy
Intimate partner femicide-suicide (IPF-S) is an understudied subgroup of homicide-suicide deaths. Limited research has been conducted on IPF-Ss in the Eastern Mediterranean region. This study thus aimed to evaluate the characteristics of IPF-Ss that occurred in Turkiye between 2000 and 2019. IPF-Ss (n = 226) were extracted from electronic news stories. Data on victims, perpetrators, their relationships, and incidents of murder and suicide were collected. Descriptive statistics were calculated, and logistic regression analysis, mortality rates, and proportion of IPF-S in femicide calculations were conducted, showing that 13.3% of the femicides (n = 1699) were IPF-Ss. The IPF-Ss increased in 5-year intervals and were the highest during the 2015-2019 period (62.5%). Victims were married in 48.2% of the cases and 56% were aged <35 years, while 51.3% of the perpetrators were married and 52.6% were aged >40 years. In 42.0% of the cases, the perpetrator lived with the victim. Most (79.2%) of the cases took place in urban settlements, and the perpetrators used firearms in 84.1% of femicide cases. Firearm use was the most common method in cases where IPF-S was planned (OR = 2.98), when the IPF-S method was the same (OR = 29.6), and when the perpetrator committed suicide (OR = 7.82). In addition, it was found that firearm ownership is an important risk factor for IPF-S in Turkiye. Therefore, we recommend legislation to restrict firearms, as well as new measures to prevent illegal access to weapons.
Citation Count: 7
Applying Emmert's Law to the Poggendorff illusion
(Frontiers Research Foundation, 2015) Talasli, Umur; Inan, Asli Bahar; Department of Psychology
The Poggendorff illusion was approached with a novel perspective, that of applying Emmert's Law to the situation. The extensities between the verticals and the transversals happen to be absolutely equal in retinal image size, whereas the registered distance for the verticals must be smaller than that of the transversals due to the fact that the former is assumed to occlude the latter. This combination of facts calls for the operation of Emmert's Law, which results in the shrinkage of the occluding space between the verticals. Since the retinal image shows the transversals to be in contact with the verticals, the shrinkage must drag the transversals inwards in the cortical representation in order to eliminate the gaps. Such dragging of the transversals produces the illusory misalignment, which is a dictation of geometry. Some of the consequences of this new explanation were tested in four different experiments. In Experiment 1, a new illusion, the tilting of an occluded continuation of an oblique line, was predicted and achieved. In Experiments 2 and 3, perceived nearness of the occluding entity was manipulated via texture density variations and the predicted misalignment variations were confirmed by using a between-subjects and within-subjects designs, respectively. In Experiment 4, tilting of the occluded segment of the transversal was found to vary in the predicted direction as a result of being accompanied by the same texture cues used in Experiments 2 and 3.
Citation Count: 2
Assessment of pulmonary arterial hemodynamic and vascular changes by pulmonary pulse transit time in patients with human immunodeficiency virus infection
(Wolters Kluwer Medknow Publications, 2021) Erdol, Mehmet Akif; Acar, Burak; Ertem, Ahmet Goktug; Karanfil, Mustafa; Yayla, Cagri; Demirtas, Koray; Akcay, Adnan Burak
Introduction: Pulmonary arterial hypertension and human immunodeficiency virus (HIV) infection is a well-known association. Pulmonary pulse transit time (pPTT) is a recent echocardiographic marker that might be used for evaluation of pulmonary arterial stiffness (PAS) in patients with HIV infection. We aimed to investigate whether pPTT elevated in patients with HIV infection compared to healthy controls and its association with echocardiographic indices of right ventricular functions. Materials and Methods: Fifty HIV (+) patients from infectious disease outpatient clinics and fifty age- and sex-matched HIV (-) healthy volunteers were enrolled in this study. pPTT was measured from pulmonary vein flow velocity as the time interval between the R-wave in the electrocardiography and corresponding peak late systolic was then calculated as the mean from two separate pw-Doppler measurements. Results: pPTT, tricuspid annular peak systolic excursion (TAPSE) and right ventricle fractional area change (FAC) were significantly lower in patients with HIV than control patients (177.1 +/- 34.9 vs. 215.7 +/- 35.7 msn, P < 0.001; 2.33 +/- 0.28 vs. 2.19 +/- 0.22, P = 0.039; 45 [4.25] vs. 41.1 [4.0], P = 0.032, respectively). pPTT was positively correlated with FAC, TAPSE and cluster of differentiation 4 count (r = 0.210; P = 0.036, r = 0.256; P = 0.041, r = 0.304; P = 0.044, respectively). Conclusion: Our study showed that pPTT, TAPSE, and right ventricle FAC levels were lower in patients with HIV infection. pPTT is an important predictor in patients with HIV expected to develop pulmonary vascular pathology.
Citation Count: 11
Atomistic Engineering of Chemiluminogens: Synthesis, Properties and Polymerization of 2,3-Dihydro-Pyrrolo[3,4-d]Pyridazine-1,4-Dione Scaffolds
(Springer/plenum Publishers, 2017) Algi, Melek Pamuk; Oztas, Zahide; Tirkes, Seha; Cihaner, Atilla; Algi, Fatih; Chemical Engineering
Two chemiluminescent compounds containing 2,5-di(thien-2-yl)pyrrole and pyridazine units, namely 5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (5) and 6-phenyl-5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (6), were successfully synthesized and electrochemically polymerized. The compounds have chemiluminescent properties and glow in the presence of hydrogen peroxide in basic medium. The intensity of the glow can be increased dramatically by using Fe3+ ions, hemin (1.0 ppm) or blood samples (1.0 ppm) as catalyst. The compounds 5 and 6 have one well-defined irreversible oxidation peak at 1.08 V and 1.33 V vs Ag/AgCl, respectively. Electrochemical polymerization of both 5 and 6 were carried out successfully by repeating potential scanning in the presence of BF3. Et2O in an electrolyte solution of 0.1 M LiClO4 dissolved in acetonitrile. The electronic band gaps (E-g) of the polymers P5 and P6 were found to be 2.02 eV and 2.16 eV, respectively. On the other hand, the corresponding polymers are electroactive and exhibited electrochromic features.
Citation Count: 0
Author`s Reply
(Turkish Society of Cardiology, 2020) Karaduman,B.D.; Ayhan,H.; Keleş,T.; Bozkurt,E.
[No abstract available]
Citation Count: 9
Biomechanical comparison of sinus floor elevation and alternative treatment methods for dental implant placement
(Taylor & Francis Ltd, 2017) Kucukkurt, Sercan; Alpaslan, Goekhan; Kurt, Ahmet
Objective: In this study, we compared the success of sinus lifting and alternative treatment methods in applying dental implants in cases lacking adequate bone due to pneumatization of the maxillary sinus. Methods: In a computer environment, 3D models were created using computerized tomography data from a patient. Additionally, implants and abutments were scanned at the macroscopic level, and the resulting images were transferred to the 3D models. Five different models were examined: a control model, lateral sinus lifting (LSL), short dental implant placement (SIP), tilted implant placement (TIP) and distal prosthetic cantilever (DC) use. Vertical and oblique forces were applied in each model. The compression, tension and von Mises stresses in each model were analyzed by implementing a finite element analysis method. Results: In our study, the LSL method was observed to be the closest to the control model. The TIP model showed high stress values under conditions of oblique forces but showed successful results under conditions of vertical forces, and the opposite results were observed in the SIP model. The DC model provided the least successful results among all models. Conclusions: Based on the results of this study, the LSL method should be the first choice among treatment options. Considering its successful results under conditions of oblique forces, the SIP method may be preferable to the TIP method. In contrast, every effort should be made to avoid the use of DCs.
Citation Count: 8
Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part One: Superior Repositioning Surgery
(Lippincott Williams & Wilkins, 2016) Kilinc, Yeliz; Erkmen, Erkan; Kurt, Ahmet
The aim of the current study was to comparatively evaluate the mechanical behavior of 3 different fixation methods following various amounts of superior repositioning of mandibular anterior segment. In this study, 3 different rigid fixation configurations comprising double right L, double left L, or double I miniplates with monocortical screws were compared under vertical, horizontal, and oblique load conditions by means of finite element analysis. A three-dimensional finite element model of a fully dentate mandible was generated. A 3 and 5mm superior repositioning of mandibular anterior segmental osteotomy were simulated. Three different finite element models corresponding to different fixation configurations were created for each superior repositioning. The von Mises stress values on fixation appliances and principal maximum stresses (P-max) on bony structures were predicted by finite element analysis. The results have demonstrated that double right L configuration provides better stability with less stress fields in comparison with other fixation configurations used in this study.
Citation Count: 7
Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part Two: Superior Repositioning Surgery With Bone Allograft
(Lippincott Williams & Wilkins, 2016) Kilinc, Yeliz; Erkmen, Erkan; Kurt, Ahmet
In this study, the biomechanical behavior of different fixation methods used to fix the mandibular anterior segment following various amounts of superior repositioning was evaluated by using Finite Element Analysis (FEA). The three-dimensional finite element models representing 3 and 5mm superior repositioning were generated. The gap in between segments was assumed to be filled by block bone allograft and resignated to be in perfect contact with the mandible and segmented bone. Six different finite element models with 2 distinct mobilization rate including 3 different fixation configurations, double right L (DRL), double left L (DLL), or double I (DI) miniplates with monocortical screws, correspondingly were created. A comparative evaluation has been made under vertical, horizontal and oblique loads. The von Mises and principal maximum stress (P-max) values were calculated by finite element solver programme. The first part of our ongoing Finite Element Analysis research has been adressed to the mechanical behavior of the same fixation configurations in nongrafted models. In comparison with the findings of the first part of the study, it was concluded that bone graft offers superior mechanical stability without any limitation of mobilization and less stress on the fixative appliances as well as in the bone.
Citation Count: 2
Characterization of mesenchymal stem cells in mucolipidosis type II (I-cell disease)
(Tubitak Scientific & Technological Research Council Turkey, 2019) Köse, Sevil; Kaya, Fatima Aerts; Kuşkonmaz, Bülent Barış; Çetinkaya, Duygu Uçkan; Nutrition and Dietetics
Mucolipidosis type II (ML-II, I-cell disease) is a fatal inherited lysosomal storage disease caused by a deficiency of theenzyme N-acetylglucosamine-1-phosphotransferase. A characteristic skeletal phenotype is one of the many clinical manifestationsof ML-II. Since the mechanisms underlying these skeletal defects in ML-II are not completely understood, we hypothesized that adefect in osteogenic differentiation of ML-II bone marrow mesenchymal stem cells (BM-MSCs) might be responsible for this skeletalphenotype. Here, we assessed and characterized the cellular phenotype of BM-MSCs from a ML-II patient before (BBMT) and afterBM transplantation (ABMT), and we compared the results with BM-MSCs from a carrier and a healthy donor. Morphologically, wedid not observe differences in ML-II BBMT and ABMT or carrier MSCs in terms of size or granularity. Osteogenic differentiation wasnot markedly affected by disease or carrier status. Adipogenic differentiation was increased in BBMT ML-II MSCs, but chondrogenicdifferentiation was decreased in both BBMT and ABMT ML-II MSCs. Immunophenotypically no significant differences were observedbetween the samples. Interestingly, the proliferative capacity of BBMT and ABMT ML-II MSCs was increased in comparison to MSCsfrom age-matched healthy donors. These data suggest that MSCs are not likely to cause the skeletal phenotype observed in ML-II, butthey may contribute to the pathogenesis of ML-II as a result of lysosomal storage-induced pathology.
Chronic Pregabalin Treatment Reduced Anxiety, and Acute Pregabalin Treatment Increased Depression-Like Behaviors in Rats
(Bmc, 2024) Caliskan, Hasan; Akat, Firat; Dursun, Ali Dogan; Zaloglu, Nezahet; Basic Sciences
BackgroundPregabalin is an antiepileptic drug that binds to the alpha-2/delta unit at presynaptic voltage-dependent calcium channels. We aimed to investigate the effect of acute and chronic pregabalin administration on anxiety and depression-like behaviors.MethodsFifty-six male Wistar albino rats were divided into seven groups: control, vehicle, and five different dose groups (5, 10, 30, 60, and 100 mg/kg). Pregabalin was administered for two weeks. Depression-like behaviors were evaluated by Forced swimming test. Anxiety-like behavior (ALB) was evaluated by Open field test (OFT), Elevated Plus Maze (EPM), and light-dark box. Subjects underwent the forced swimming test (FST) after the first dose, while the open field test (OFT), elevated plus maze (EPM), and light-dark box (LDB) were performed after two weeks of treatment. Further sucrose preference test was conducted to evaluate anhedonia until the end of the experiment.ResultsIn the forced swimming test, depression-like behaviors increased after acute single-dose administration of 10, 30, 60, 100 mg/kg pregabalin. According to OFT results, chronic 100 mg/kg pregabalin showed anxiolytic effects by decreasing grooming, and freezing behaviors. In addition, 100 mg/kg chronic pregabalin administration significantly increased the time spent in the central region, the number of entries to the center, and the unsupported rearing number without causing any change in locomotor activity. According to EPM results, both chronic 60 and 100 mg/kg pregabalin treatments showed anxiolytic effects by increasing open arm time and head dipping behavior. In addition, 60 and 100 mg/kg chronic pregabalin administration significantly decreased stretch attend posture. All pregabalin administrations between 5 and 100 mg/kg displayed anxiolytic effects in the LDB. Sucrose preference was above 65% for the duration of all experiments and subjects did not show anhedonia.ConclusionAcute pregabalin treatment triggered depression-like behaviors. Anhedonia, which may be associated with depression, was not observed during chronic treatment. Moreover, chronic treatment with pregabalin revealed potent anxiolytic effects in different behavior patterns and doses for all tests of unconditional anxiety. In particular, 100 mg/kg chronic pregabalin administration decreased anxiety-like behaviors in all experiment setups. Although the anxiolytic effect was demonstrated in chronic treatment, acute treatment of pregabalin induced depression-like behaviors, and thus in clinical practice should be done with caution, especially in patients with anxiety-depression comorbidity.
Citation Count: 2
Clinical and Demographic Characteristics of Cutaneous Mastocytosis in Childhood: Single-center Experience
(Lippincott Williams and Wilkins, 2022) Erdem,A.Y.; Özyörük,D.; Emir,S.; Çakmakçı,S.; Ceylan,G.G.; Toyran,M.; Mısırlıoğlu,E.D.
Introduction: Mastocytosis is a rare and heterogenous disease, and in children it is generally limited to the skin and tends to regress spontaneously in adolescence. Aim: In this study, demographic, clinical, and laboratory characteristics of pediatric patients with mastocytosis, and also coexisting diseases were investigated. Results: A total of 61 pediatric patients were included in the study. The male-to-female ratio was 2.2, the median age was 2 years (range, 0.25 to 19 y), and the median follow-up period was 2.0 years (range, 0.25 to 19 y). Types of clinical presentation at diagnosis consisted of mainly urticaria pigmentosa (45.9%). Seven patients were further investigated with suspicion of systemic mastocytosis, they were followed up, median of 9 years (range, 2.5 to 16 y), and none of them developed systemic disease. Coexisting allergic diseases were recorded in total 5 patients (8.2%). Three patients had immunoglobulin A deficiency, 1 patient had elevated immunoglobulin E level. A patient developed mature B-cell lymphoma with a heterozygous mutation in c-KIT exon 11. Discussion: Cutaneous mastocytosis in children may present as a complex disease with different clinical signs and symptoms. Standardized clinical criteria and guidelines for the follow-up of children with mastocytosis are required. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.
Citation Count: 7
Comparison of NAT1, NAT2 & GSTT2-2 activities in normal and neoplastic human breast tissues
(SAP - Slovak Academic Press, spol. s.r.o., 2006) Geylan-Su,Y.S.; Isgör,B.; Coban,T.; Kapucuoglu,N.; Aydintug,S.; Iscan,M.; Güray,T.
In this study, arylamine N-acetyltransferases, NATs (E.C.2.3.1.5) and glutathione-S-transferase-T2-2, GSTT2-2 (E.C.2.5.1.18) enzyme activities in the breast tumor and surrounding tumor-free tissues of 22 female breast cancer patients with infiltrating ductal carcinoma were measured. The possible impacts of grade of malignancy, chemotherapy treatment, estrogen receptor status and menopausal status on all enzyme activities were evaluated. The results showed that, both NAT2 and GSTT2-2 display significant differences between tumor and tumor-free breast tissues, while no difference was observed in NAT1. Grade of malignancy seems to be positively associated with NAT1 and negatively associated with GSTT2-2. Though, both NAT2 and GSTT2-2 have increased mean tumor activities, the grade of malignancy, chemotherapy status, menopausal status or estrogen receptor status are not correlated statistically.
Citation Count: 6
Comparison of NAT1, NAT2 & GSTT2-2 activities in normal and neoplastic human breast tissues
(Aepress Sro, 2006) Geylan-SU, YS; Isgör, B; Coban, T; Kapucuoglu, N; Aydintug, S; Iscan, M; Güray, T; Chemical Engineering
In this study, arylamine N-acetyltransferases, NATs (E.C.2.3.1.5) and glutathione-S-transferase-T2-2, GSTT2-2 (E.C.2.5.1.18) enzyme activities in the breast tumor and surrounding tumor-free tissues of 22 female breast cancer patients with infiltrating ductal carcinoma were measured. The possible impacts of grade of malignancy, chemotherapy treatment, estrogen receptor status and menopausal status on all enzyme activities were evaluated. The results showed that, both NAT2 and GSTT2-2 display significant differences between tumor and tumor-free breast tissues, while no difference was observed in NAT1. Grade of malignancy seems to be positively associated with NAT1 and negatively associated with GSTT2-2. Though, both NAT2 and GSTT2-2 have increased mean tumor activities, the grade of malignancy, chemotherapy status, menopausal status or estrogen receptor status are not correlated statistically.
Citation Count: 10
Comparison of Physicochemical Properties of Two Types of Polyepichlorohydrin-Based Anion Exchange Membranes for Reverse Electrodialysis
(Mdpi, 2022) Karakoc, Ezgi; Guler, Enver; Chemical Engineering
The development of the most effective, suitable and economic ion-exchange membranes is crucial for reverse electrodialysis (RED)-the most widely studied process to harvest salinity gradient energy from mixing seawater and river water. RED utilizes two types of membranes as core elements, namely cation exchange membranes (CEM) and anion exchange membranes (AEM). Since the preparation of AEMs is more complex compared to CEMs, the design and development of anion exchange membranes have been the focus in this study. Homogeneous AEMs based on two types of polyepichlorohydrin (PECH) with different chlorine amounts (PECH-H, 37 wt% and PECH-C, 25 wt%) were synthesized, and first-time benchmarking of the membrane properties was conducted. In addition to physicochemical membrane properties, some instrumental analyses such as SEM, FTIR and DSC were investigated to characterize these anion-exchange membranes. Based on the results, although the PECH-H-type membrane had enhanced ion-exchange properties, PECH-C-based anion-exchange membranes exhibited a higher power density of 0.316 W/m(2) in a lab-scale RED system. Evidently, there is room for the development of new types of PECH-C-based AEMs with great potential for energy generation in the RED process.
Citation Count: 1
Comparison of the Effectiveness of Kinesiology Taping and Rigid Taping on Ankle Kinematics During Drop Landing in Individuals with Lateral Ankle Injury
(American Podiatric Medical Association, 2022) Korkusuz,S.; Kilic,R.T.; Aritan,S.; Ozgoren,N.; Sozay,S.; Kibar,S.; Yosmaoglu,H.B.; Chemical Engineering
Background: Lateral ankle sprain is an injury that often occurs during sports or daily life activ-ities. Athletic tape and kinesiology tape applications are among the external support treatment options especially for athletes to support the ankle and protect it from recurrent sprains. We sought to compare the kinematic stabilization effects of different ankle taping applications on the ankle joint during drop landing in individuals with a history of unilateral lateral ankle injury. Methods: In this randomized controlled study, 30 volunteers with unilateral ankle injury were evaluated. The participants were asked to land on one leg on the involved side and the contralateral side from a 30-cm-high platform. The same practice was repeated after apply-ing kinesiology tape and rigid tape to the injured foot. Kinematic analysis of the foot and ankle was performed by recording three-dimensional spatial position information at a speed of 240 frames per second using infrared cameras. Results: The highest inversion angles of the involved foot at initial contact and 150 msec after initial contact were higher than those of the uninvolved side (P = .03 and P = .04, respec-tively). There was no significant difference in ankle kinematic values in the involved foot among kinesiology taping, athletic taping, and no taping applications (P = .74). Conclusions: People with lateral ankle sprains show reduced inversion during landing. There were no significant differences among kinesiology taping, athletic taping, and no taping on the injured foot in terms of ankle kinematics. Care should be taken when using taping materials as protective measures for sports activities. © 2022, American Podiatric Medical Association. All rights reserved.
Citation Count: 1
Comparison of the Effectiveness of Kinesiology Taping and Rigid Taping on Ankle Kinematics During Drop Landing in Individuals with Lateral Ankle Injury
(American Podiatric Medical Association, 2022) Korkusuz,S.; Kilic,R.T.; Aritan,S.; Ozgoren,N.; Sozay,S.; Kibar,S.; Yosmaoglu,H.B.; Chemical Engineering
Background: Lateral ankle sprain is an injury that often occurs during sports or daily life activ-ities. Athletic tape and kinesiology tape applications are among the external support treatment options especially for athletes to support the ankle and protect it from recurrent sprains. We sought to compare the kinematic stabilization effects of different ankle taping applications on the ankle joint during drop landing in individuals with a history of unilateral lateral ankle injury. Methods: In this randomized controlled study, 30 volunteers with unilateral ankle injury were evaluated. The participants were asked to land on one leg on the involved side and the contralateral side from a 30-cm-high platform. The same practice was repeated after apply-ing kinesiology tape and rigid tape to the injured foot. Kinematic analysis of the foot and ankle was performed by recording three-dimensional spatial position information at a speed of 240 frames per second using infrared cameras. Results: The highest inversion angles of the involved foot at initial contact and 150 msec after initial contact were higher than those of the uninvolved side (P = .03 and P = .04, respec-tively). There was no significant difference in ankle kinematic values in the involved foot among kinesiology taping, athletic taping, and no taping applications (P = .74). Conclusions: People with lateral ankle sprains show reduced inversion during landing. There were no significant differences among kinesiology taping, athletic taping, and no taping on the injured foot in terms of ankle kinematics. Care should be taken when using taping materials as protective measures for sports activities. © 2022, American Podiatric Medical Association. All rights reserved.
Citation Count: 5
Comparison of the Stability of Sandblasted, Large-Grit, and Acid-Etched Treated Mini-Screws With Two Different Surface Roughness Values: A Histomorphometric Study
(Lippincott Williams & Wilkins, 2022) Seker, Elif Dilara; Yavuz, Ibrahim; Yucesoy, Turker; Cenkci, Ebru; Yay, Arzu
Purpose: To evaluate the effects of 2 different surface roughness values produced by sandblasted, large-grit, and acid-etched treatments at different loading conditions on the stability of mini-screws. Material and Methods: A total of 56 mini-screws (Group 1; 28 with Ra value of 1 mm, Group 2; 28 with Ra value of 1.5 mu m) were inserted into the tibia of fourteen New Zealand rabbits. Surface analysis was performed before the placement of the miniscrews using multi-technique characterization. The mini-screws were loaded with 500 grf after different healing times: unloaded, immediate, 4 and 8 weeks. Resonance frequency analyses were performed immediately after mini-screw placement and at the end of loading. Biomechanical and histomorphometric analyses were also performed at the end of the loading period. Results: All mini-screws preserved their stability at the end of the loading period. However, the resonance frequency analyses showed higher implant stability quotient scores for 8-week group, unlike the immediate loading and unloaded groups (P < 0.05). According to the infinite focus microscopy results, prolongation of healing time resulted in a greater bone area on the loaded mini-screws in Group 2 (P < 0.05). Similarly, the histomorphometric analysis revealed higher bone-to-implant contact values in the 8-week group. There was no significant difference in the stability between the miniscrews with the Ra values of 1 and 1.5 mu m. Conclusions: Sandblasted, large-grit, and acid-etched treated miniscrews showed significantly higher stability with healing time under heavy forces. Sandblasted, large-grit, and acid-etched treated miniscrews can be removed without fracture of the screw or the bone surfaces.
Citation Count: 10
A computational study on 4,7-di(furan-2-yl)benzo[c][1,2,5]thiadiazole monomer and its oligomers
(Springer, 2014) Kayi, Hakan; Chemical Engineering
The energy gap, Eg, between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels that determines the electronic and optical properties of 4,7-di(furan-2yl)benzo[c][1,2,5]thiadiazole (FSF) polymer is calculated by performing quantum chemical calculations. First, we theoretically investigated the most stable conformers of FSF monomer and its corresponding oligomers at the B3LYP/6-31G(d) and B3LYP/LANL2DZ levels of theory. We reveal the theoretical molecular structure of this very recently synthesized novel monomer and its oligomers for the first time in the literature. Our results from the B3LYP/6-31G(d) calculations indicated that FSF polymer has a low HOMO-LUMO gap of 1.55 eV to be in good agreement with the experiments. Experimental design and synthesis of novel conjugated polymers require time-consuming and expensive procedures. The findings from this study are promising for the use of computational methods in the design of the novel conjugated polymers, and help to narrow the materials to be used in design and synthesis of conjugated polymers with desired properties.
Citation Count: 8
Conformational behaviors of trans-2,3-and trans-2,5-dihalo-1,4-diselenanes. A complete basis set, hybrid-density functional theory study and natural bond orbital interpretations
(Springer, 2014) Nori-Shargh, Davood; Mousavi, Seiedeh Negar; Kayi, Hakan; Chemical Engineering
Complete basis set CBS-4, hybrid-density functional theory (hybrid-DFT: B3LYP/6-311+G**) based methods and natural bond orbital (NBO) interpretations have been used to examine the contributions of the hyperconjugative, electrostatic, and steric effects on the conformational behaviors of trans-2,3-dihalo-1,4-diselenane [halo = F (1), Cl (2), Br (3)] and trans-2,5-dihalo-1,4-diselenane [halo = F (4), Cl (5), Br (6)]. Both levels of theory showed that the axial conformation stability, compared to its corresponding equatorial conformation, decreases from compounds 1 -> 3 and 4 -> 6. Based on the results obtained from the NBO analysis, there are significant anomeric effects for compounds 1-6. The anomeric effect associated with the electron delocalization is in favor of the axial conformation and increases from compounds 1 -> 3 and 4 -> 6. On the other hand, dipole moment differences between the axial and equatorial conformations [Delta(mu(eq) - mu(ax))] decrease from compounds 1 -> 3. Although Delta(mu(eq)-mu(ax)) parameter decreases from compound 1 to compound 3, the dipole moment values of the axial conformations are smaller than those of their corresponding equatorial conformations. Therefore, the anomeric effect associated with the electron delocalizations (for halogen-C-Se segments) and the electrostatic model associated with the dipole-dipole interactions fail to account for the increase of the equatorial conformations stability on going from compound 1 to compound 3. Since there is no dipole moment for the axial and equatorial conformations of compounds 4-6, consequently, the conformational preferences in compounds 1-6 is in general dictated by the steric hindrance factor associated with the 1,3-syn-axial repulsions. Importantly, the CBS-4 results show that the entropy difference (Delta S) between the equatorial axial conformations increases from compounds 1 -> 3 and 4 -> 6. This fact can be explained by the anomeric effect associated with the electron delocalization which affects the C-2-Se bond orders and increase the rigidity of the corresponding rings. The Gibbs free energy difference values between the axial and equatorial conformations (i.e. Delta G(ax-ax) and Delta G(eq-eq)) of compounds 1 and 4, 2 and 5 and also 3 and 6 have been calculated. The correlations between the anomeric effect, electrostatic model, Delta G(eq-ax), Delta G(ax-ax), Delta G(eq-eq), bond orders, dipole-dipole interactions, structural parameters and conformational behaviors of compounds 1-6 have been investigated.

Browse

Browsing Pubmed by Scopus Q "Q3"