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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/22

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Citation - WoS: 1
Citation - Scopus: 1
Adaptive Stimulus Design for Dynamic Recurrent Neural Network Models
(Frontiers Media Sa, 2019) Doruk, R. Ozgur; Zhang, Kechen; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
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 - WoS: 80
Citation - Scopus: 81
Amine Grafted Silica Supported Craupd Alloy Nanoparticles: Superb Heterogeneous Catalysts for the Room Temperature Dehydrogenation of Formic Acid
(Royal Soc Chemistry, 2015) Yurderi, Mehmet; Bulut, Ahmet; Caner, Nurdan; Celebi, Metin; Kaya, Murat; Zahmakiran, Mehmet; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Herein we show that a previously unappreciated combination of CrAuPd alloy nanoparticles and amine-grafted silica support facilitates the liberation of CO-free H-2 from dehydrogenation of formic acid with record activity in the absence of any additives at room temperature. Furthermore, their excellent catalytic stability makes them isolable and reusable heterogeneous catalysts in the formic acid dehydrogenation.
Citation - WoS: 6
Citation - Scopus: 8
Applying Emmert's Law To the Poggendorff Illusion
(Frontiers Research Foundation, 2015) Talasli, Umur; Inan, Asli Bahar; Department of Psychology; 02. School of Arts and Sciences; 01. Atılım University
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 - WoS: 1
Citation - Scopus: 1
Assessment of Anticancer Effects of Aloe Vera on 3D Liver Tumor Spheroids in a Microfluidic Platform
(Wiley, 2025) Tevlek, Atakan; Kibar, Gunes; Cetin, Barbaros; Basic Sciences; 08. Medical School; 01. Atılım University
The search for effective anticancer therapies has increasingly focused on natural compounds like Aloe vera, renowned for its therapeutic properties. This study investigates the anticancer properties of Aloe vera on 3D liver tumor spheroids via a PDMS-based microfluidic device, providing a more physiologically realistic model compared to traditional 2D cultures. HepG2 cells were cultivated to generate 3D spheroids on-chip, thereafter subjected to different concentrations of Aloe vera and the chemotherapeutic drug Doxorubicin to evaluate cytotoxic effects. The microfluidic system, validated by COMSOL simulations, facilitated continuous perfusion and real-time assessment of cell viability over a duration of 10 days. The results indicated that Aloe vera markedly diminished cell viability by triggering apoptosis at concentrations over 12.5 mg/mL. IC50 values were determined at 72 h: 25 +/- 0.10 mg/mL for Aloe vera and 5.47 +/- 0.03 mu g/mL for Doxorubicin in 2D cultures, but in 3D cultures, the IC50 values were 31.25 +/- 0.14 mg/mL for Aloe vera and 8.33 +/- 0.05 mu g/mL for Doxorubicin. This study underscores the promise of Aloe vera as a natural anticancer agent and illustrates the efficacy of microfluidic platforms for enhanced drug screening and customized medicine applications.
Citation - WoS: 19
Citation - Scopus: 20
Assessment of Depression, Anxiety, and Social Support in the Context of Therapeutic Abortion
(Wiley, 2019) Topal, Cansu Akdag; Terzioglu, Fusun; Nursing; 07. School of Health Sciences; 01. Atılım University
Purpose The purpose of this study is to determine the levels of anxiety, depression, social support, and nursing care needed by women undergoing therapeutic abortion. Designs and Methods Sixty women were administered a sociodemographic form, the Hospital Anxiety Depression Scale and the Multidimensional Perceived Social Support Scale. Results More than half of the women experienced anxiety (61.7%). Anxiety scores were high (10.8 +/- 3.7), and most of the women had depression (85.0%). Social support from family and friends of the women decreased the women's anxiety and depression levels significantly; social support from their partners also decreased the women's anxiety levels (P < 0.05). Practice Implications Support from family and friends after therapeutic abortion is a fundamental affective variable on anxiety scores.
Citation - WoS: 5
Citation - Scopus: 5
Assessment of Nitrogen Excess in an Agricultural Area Using a Nitrogen Balance Approach
(I W A Publishing, 2005) Muhammetoglu, H; Muhammetoglu, A; Soyupak, S; 01. Atılım University
A pilot study has been initiated to develop an approach for quantification of nitrogen excesses from agricultural activities that involve greenhouse farming in Kumluca Plain, Turkey. Detailed calculations utilizing the nitrogen balance method (NBM) were carried out at nine different locations within the plain over a time period of one year. The major contributing factors and governing operative mechanisms taken into consideration were nitrogen application rates both as organic and chemical fertilizers, irrigation water to application practices, and nitrogen uptake by plants. The adopted approach yielded valuable information such as plant nitrogen uptake efficiencies, excess nitrogen, leaching rates and leachate nitrogen concentrations. Further, a site specific multiple linear regression model has been developed to estimate the ratio (N-leachate/N-groundwater) as a function of independent variables: farming age, excess nitrogen application and SEEPAGE Index Number. The negative sign of the model parameters implies that the ratio (N-leachate/N-groundwater) decreases as values of the independent variables increase. The adopted approach and the obtained results can beneficially be applied to similar sites to establish basic parameters of irrigation and fertilizer application operations.
The Association Between Digital Device Usage Behaviors and the Incidence of De Quervain’s Tenosynovitis Among University Students
(Taylor and Francis Ltd., 2025) Jamil, Y.; Öktem, H.; Sever, S.N.; Basic Sciences; 08. Medical School; 01. Atılım University
Background: The extensive use of mobile and digital devices has been implicated in various musculoskeletal disorders, including de Quervain’s tenosynovitis (dQD), a condition affecting the thumb. Purpose: The present study investigates the relationship between digital device usage patterns and the prevalence of dQD among university students. Methods: A cross-sectional study was conducted with 508 participants (255 females and 253 males), collecting data on daily device use time, wrist positions, hand dominance, and stretching practices via a questionnaire. Data collection was carried out through a supervised, face-to-face survey. Diagnosis of dQD was determined using Finkelstein’s test, all data were analyzed using SPSS software. Results: Out of 508 participants, 187 (36.8%) tested positive for dQD, with 152 (95.6)% occurring in the dominant hand (p =.006, Cramér’s (Formula presented.) = 0.121). 250 participants used their devices with wrists in ulnar deviation (49.2%), which was strongly linked to a positive Finkelstein test result (p =.004, Cramér’s (Formula presented.) = 0.175). Finkelstein’s test showed increasing positivity with device use, ranging from 12.5% for < 2 hours to 46.2% for ≥ 8 hours, with a statistically significant association (p <.001, Cramér’s (Formula presented.) = 0.234). Device usage varied, with the highest test positivity rates among those using devices 6–8 hours per day suggesting a significant association with dQD (p =.001). No significant relationship was found between dQD and the practice of stretching or relieving movements (p =.146). Conclusion: The findings indicate that prolonged digital device usage, specific wrist positions such as ulnar deviation, and dominant-hand use are significantly associated with an increased risk of de Quervain’s tenosynovitis among college students. © 2025 Taylor & Francis Group, LLC.
Citation - WoS: 58
Citation - Scopus: 68
Atmospheric Pressure Plasma Surface Treatment of Polymers and Influence on Cell Cultivation
(Mdpi, 2021) Sasmazel, Hilal Turkoglu; Alazzawi, Marwa; Alsahib, Nabeel Kadim Abid; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Atmospheric plasma treatment is an effective and economical surface treatment technique. The main advantage of this technique is that the bulk properties of the material remain unchanged while the surface properties and biocompatibility are enhanced. Polymers are used in many biomedical applications; such as implants, because of their variable bulk properties. On the other hand, their surface properties are inadequate which demands certain surface treatments including atmospheric pressure plasma treatment. In biomedical applications, surface treatment is important to promote good cell adhesion, proliferation, and growth. This article aim is to give an overview of different atmospheric pressure plasma treatments of polymer surface, and their influence on cell-material interaction with different cell lines.
Citation - WoS: 16
Citation - Scopus: 19
Attachment Style, Openness To Experience, and Social Contact as Predictors of Attitudes Toward Homosexuality
(Routledge Journals, Taylor & Francis Ltd, 2020) Metin-Orta, Irem; Metin-Camgoz, Selin; Department of Psychology; 02. School of Arts and Sciences; 01. Atılım University
Considerable research has shown that people generally hold more negative attitudes toward homosexuals. Given this fact, it is important to understand psychological and social correlates of homophobia. With this purpose, the present study investigates attachment styles, openness to experience, and social contact in relation to attitudes toward homosexuals. The findings show that being female, having prior contact with homosexuals, and scoring high in openness to experience predict more favorable attitudes toward homosexuals. The supplementary analyses also support the moderating effect of secure attachment on the relationship between openness to experience and attitudes toward homosexuals. The present study not only extends the related research by examining the interactive effects of attachment style and personality trait, but also provides important implications for researchers, educators, or managers in terms of reducing anti-homosexual attitudes in diverse settings.
Author Correction: Using Urine Ftir Spectra To Screen Autism Spectrum Disorder
(Nature Portfolio, 2024) Sarigul, Neslihan; Bozatli, Leyla; Kurultak, Ilhan; Korkmaz, Filiz; Physics Group; 06. School Of Engineering; 01. Atılım University
[No Abstract Available]
Citation - WoS: 5
Citation - Scopus: 4
Avoiding Contingent Incidents by Quadrotors Due To One or Two Propellers Failure
(Public Library Science, 2023) Altinuc, Kemal Orcun; Khan, Muhammad Umer; Iqbal, Jamshed; Mechatronics Engineering; 15. Graduate School of Natural and Applied Sciences; 06. School Of Engineering; 01. Atılım University
With the increasing impact of drones in our daily lives, safety issues have become a primary concern. In this study, a novel supervisor-based active fault-tolerant (FT) control system is presented for a rotary-wing quadrotor to maintain its pose in 3D space upon losing one or two propellers. Our approach allows the quadrotor to make controlled movements about a primary axis attached to the body-fixed frame. A multi-loop cascaded control architecture is designed to ensure robustness, stability, reference tracking, and safe landing. The altitude control is performed using a proportional-integral-derivative (PID) controller, whereas linear-quadratic-integral (LQI) and model-predictive-control (MPC) have been investigated for reduced attitude control and their performance is compared based on absolute and mean-squared error. The simulation results affirm that the quadrotor remains in a stable region, successfully performs the reference tracking, and ensures a safe landing while counteracting the effects of propeller(s) failures.
Citation - WoS: 9
Citation - Scopus: 7
Beyond expectations: disease duration and psychological burden in psoriatic arthritis
(Springer Heidelberg, 2023) Kilic, Gamze; Kilic, Erkan; Tekeoglu, Ibrahim; Sargin, Betul; Cengiz, Gizem; Balta, Nihan Cuzdan; Nas, Kemal; 01. Atılım University
This study aims to investigate the relationship between disease duration and psychological burden in PsA and to identify the risk factors associated with psychological distress. Patients with PsA who met CASPAR classification criteria enrolled by Turkish League Against Rheumatism (TLAR)-Network. Patients were categorized into three groups based on disease duration: early stage (< 5 years), middle stage (& GE; 5, < 10 years), and late stage (& GE; 10 years). All patients underwent clinical and laboratory assessment using standardized protocol and case report forms. The associations between psychological variables and clinical parameters were assessed by a multivariate analysis. Of the 1113 patients with PsA (63.9% female), 564 (%50.7) had high risk for depression and 263 (%23.6) for anxiety. The risk of psychological burden was similar across all PsA groups, and patients with a higher risk of depression and anxiety also experienced greater disease activity, poorer quality of life, and physical disability. Multivariate logistic regression revealed that female gender (OR = 1.52), PsAQoL (OR = 1.13), HAQ (OR = 1.99), FiRST score (OR = 1.14), unemployment/retired (OR = 1.48) and PASI head score (OR = 1.41) were factors that influenced the risk of depression, whereas the current or past enthesitis (OR = 1.45), PsAQoL (OR = 1.19), and FiRST score (OR = 1.26) were factors that influenced the risk of anxiety. PsA patients can experience a comparable level of psychological burden throughout the course of their disease. Several socio-demographic and disease-related factors may contribute to mental disorders in PsA. In the present era of personalized treatment for PsA, evaluating psychiatric distress can guide tailored interventions that improve overall well-being and reduce disease burden.
Citation - WoS: 54
Biomechanical Comparison of Implant Retained Fixed Partial Dentures With Fiber Reinforced Composite Versus Conventional Metal Frameworks: a 3d Fea Study
(Elsevier, 2011) Erkmen, Erkan; Meric, Gokce; Kurt, Ahmet; Tunc, Yahya; Eser, Atilim; 01. Atılım University
Fiber reinforced composite (FRC) materials have been successfully used in a variety of commercial applications. These materials have also been widely used in dentistry. The use of fiber composite technology in implant prostheses has been previously presented, since they may solve many problems associated with metal alloy frameworks such as corrosion, complexity of fabrication and high cost. The hypothesis of this study was that an FRC framework with lower flexural modulus provides more even stress distribution throughout the implant retained fixed partial dentures (FPDs) than a metal framework does. A 3-dimensional finite element analysis was conducted to evaluate the stress distribution in bone, implant-abutment complex and prosthetic structures. Hence, two distinctly different models of implant retained 3-unit fixed partial dentures, composed of Cr-Co and porcelain (M-FPD model) or FRC and particulate composite (FRC-FPD model) were utilized. In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal forces were simulated. When the FRC-FPD and M-FPD models were compared, it was found that all investigated stress values in the M-FPD model were higher than the values in the FRC-FPD model except for the stress values in the implant-abutment complex. It can be concluded that the implant supported FRC-FPD could eliminate the excessive stresses in the bone-implant interface and maintain normal physiological loading of the surrounding bone, therefore minimizing the risk of peri-implant bone loss due to stress-shielding. (C) 2010 Elsevier Ltd. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Biosorption of Reactive Dyes by Novel Bacterium Leclercia Adecarboxylata: Complete Removal of Reactive Black 5 and Molecular Insights Into the Adsorption Mechanism
(Wiley, 2025) Sen, Seda; Korkmaz, Filiz; Kilic, Nur Kocberber; Physics Group; 06. School Of Engineering; 01. Atılım University
Leclercia adecarboxylata isolated from the D & uuml;den Waterfall (Turkey) was utilized as a biosorbent for the removal of Reactive Black 5 (RB5), Setazol Blue BRF-X (BRF-X), Setazol Navy Blue SBG (SNB), and Setazol Turquoise Blue G (STBG). Of the dyes, RB5 was removed with the highest efficiency, 97.4% after 60 min. The effect of parameters such as pH (3-9), initial biosorbent dose (0.1-2.0 g/L), and initial dye concentration (25-1200 mg/L) on the biosorption of RB5 was investigated. Increasing the biosorbent dosage from 0.1 to 2.0 g/L enhanced the RB5 removal from 55.3% to 100% within 10 min. The complete removal (100%) of RB5 was achieved in media with 2.0 g/L biosorbent and 25 mg/L RB5 at pH 3 after 10 min. Additionally, the soluble extracellular polymeric substances (EPS) of L. adecarboxylata were found to consist of proteins, lipids, nucleic acids, and polysaccharides according to Fourier transform infrared spectroscopy (FTIR) analysis. The EPS was found to play a crucial role in dye removal, forming chemical interactions with dye molecules. Zeta potential analysis was used to evaluate the charge distribution on the biosorbent surface (-12.6 +/- 1.1 mV) and its interactions in the biosorption process. Kinetic and isotherm models suggested a complex interaction mechanism between the biomass and the dye. Adsorption isotherm data were analyzed via nine isotherm models. Among them, the Hill model was found to be the best fit for describing the equilibrium adsorption process of the RB5 (R2 = 0.9993). Overall, the applied models elucidated the influence of both physical and chemical interactions on the mechanism. Kinetic studies revealed that the adsorption of RB5 fit a pseudo-second-order kinetic model. The unique biochemical composition of the indigenous L. adecarboxylata biosorbent provided a high affinity for RB5, offering a sustainable, rapid, and economical solution for the treatment of dye-polluted water.
Citation - WoS: 4
Citation - Scopus: 4
Blood Metal Analysis of Plasmas From Donors With and Without Sars-Cov Using Laser-Induced Breakdown Spectroscopy and Logistic Regression
(Optica Publishing Group, 2024) Melikechi, Noureddine; Adler, Helmar G.; Safi, Ali; Landis, Joshua E.; Pourkamali-Anaraki, Farhad; Eseller, Kemal Efe; Xia, Weiming; Department of Electrical & Electronics Engineering; 15. Graduate School of Natural and Applied Sciences; 01. Atılım University
Research on the correlation between metal levels in blood and Covid-19 infection has been conducted primarily by assessing how each individual blood metal is linked to different aspects of the disease using samples from donors with various levels of severity to Covid-19 infection. Using logistics regression on LIBS spectra of plasma samples collected pre- and postCovid-19 pandemic from donors known to have developed various levels of antibodies to the SARS-Cov-2 virus, we show that relying on the levels of Na, K, and Mg together is more efficient at differentiating the two types of plasma samples than any single blood alone.
Calcium Phosphate Honeycomb Scaffolds With Tailored Microporous Walls Using Phase Separation-Assisted Digital Light Processing
(MDPI, 2025) Kim, Gyu-Nam; Park, Jae-Hyung; Song, Jae-Uk; Koh, Young-Hag; Park, Jongee; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
The present study reports on the manufacturing of biphasic calcium phosphate (BCP) honeycomb scaffolds with tailored microporous walls using phase separation-assisted digital light processing (PS-DLP). To create micropores in BCP walls, camphene was used as the pore-forming agent for preparing BCP suspensions, since it could be completely dissolved in photopolymerizable monomers composed of triethylene glycol dimethacrylate (TEGDMA) and polyethylene glycol diacrylate (PEGDA) and then undergo phase separation when placed at 5 degrees C. Therefore, solid camphene crystals could be formed in phase-separated BCP layers and then readily removed via sublimation after the photopolymerization of monomer networks embedding BCP particles by DLP. This approach allowed for tight control over the microporosity of BCP walls by adjusting the camphene content. As the camphene content increased from 40 to 60 vol%, the microporosity increased from similar to 38 to similar to 59 vol%. Consequently, the overall porosity of dual-scale porosity scaffolds increased from similar to 51 to similar to 67 vol%, while their compressive strength decreased from similar to 70.4 to similar to 13.7 MPa. The mass transport ability increased remarkably with an increase in microporosity.
Citation - WoS: 1
Citation - Scopus: 1
Cb65 and Novel Cb65 Liposomal System Suppress Mg63 and Saos-2 Osteosarcoma Cell Growth in Vitro
(Taylor & Francis Ltd, 2024) Zorba, Basak Isil; Boyacioglu, Oezge; Caglayan, Tugba; Recber, Tuba; Nemutlu, Emirhan; Eroglu, Ipek; Korkusuz, Petek; 01. Atılım University
Curable approaches for primary osteosarcoma are inadequate and urge investigation of novel therapeutic formulations. Cannabinoid ligands exert antiproliferative and apoptotic effect on osteosarcoma cells via cannabinoid 2 (CB2) or transient receptor potential vanilloid type (TRPV1) receptors. In this study, we confirmed CB2 receptor expression in MG63 and Saos-2 osteosarcoma cells by qRT-PCR and flow cytometry (FCM), then reported the reduction effect of synthetic specific CB2 receptor agonist CB65 on the proliferation of osteosarcoma cells by WST-1 (water-soluble tetrazolium-1) and RTCA (real-time impedance-based proliferation). CB65 revealed an IC50 (inhibitory concentration) for MG63 and Saos-2 cells as 1.11 x 10(-11) and 4.95 x 10(-11) M, respectively. The specific antiproliferative effect of CB65 on osteosarcoma cells was inhibited by CB2 antagonist AM630. CB65 induced late apoptosis of MG63 and Saos-2 cells at 24 and 48 h, respectively by FCM when applied submaximal concentration. A novel CB65 liposomal system was generated by a thin film hydration method with optimal particle size (141.7 +/- 0.6 nm), polydispersity index (0.451 +/- 0.026), and zeta potential (-10.9 +/- 0.3 mV) values. The encapsulation efficiency (EE%) of the CB65-loaded liposomal formulation was 51.12%. The CB65 and CB65-loaded liposomal formulation releasing IC50 of CB65 reduced proliferation by RTCA and invasion by scratch assay and induced late apoptosis of MG63 and Saos-2 cells, by FCM. Our results demonstrate the CB2 receptor-mediated antiproliferative and apoptotic effect of a new liposomal CB65 delivery system on osteosarcoma cells that can be used as a targeted and intelligent tool for bone tumors to ameliorate pediatric bone cancers following in vivo validation.
Citation - WoS: 5
Citation - Scopus: 6
Characteristic Features of Thermoluminescence in Neodymium-Doped Gallium Sulfide
(Wiley, 2018) Guler, I.; Isik, M.; Ahmedova, F.; Guseinov, A.; Gasanly, N.; Department of Electrical & Electronics Engineering; 15. Graduate School of Natural and Applied Sciences; 01. Atılım University
The thermoluminescence (TL) of neodymium-doped gallium sulfide (GaS:Nd) single crystals was measured from 10 K to room temperature with various heating rates between 0.2 and 1.0 K/sec. Two peaks centered at 70.9 K and 116.0 K were observed when using a heating rate of 0.8 K/sec. Initial rise and curve fitting methods were used to obtain information on trap activation energies. Activation energies of 94 and 216 meV were found for two analyzable peaks. The heating rate dependencies of TL intensities revealed that one of the observed peaks showed normal behavior according to the one trap-one recombination model, whereas the other model showed anomalous heating rate behavior. TL experiments were also carried out at different illumination temperatures from 10 to 32 K; maximum peak temperature remained almost the same at various illumination temperatures. This behavior indicated that the revealed trapping centers are single, discrete levels. The TL glow curves of undoped GaS crystals were also investigated and the effect of Nd doping on the TL characteristics of crystals is discussed in the manuscript.
Citation - WoS: 31
Citation - Scopus: 31
Characteristics and Outcomes of Carbapenemase Harbouring Carbapenem-Resistant klebsiella Spp. Bloodstream Infections: a Multicentre Prospective Cohort Study in an Oxa-48 Endemic Setting
(Springer, 2022) Isler, Burcu; Ozer, Berna; Cinar, Gule; Aslan, Abdullah Tarik; Vatansever, Cansel; Falconer, Caitlin; Ergonul, Onder; 01. Atılım University
A prospective, multicentre observational cohort study of carbapenem-resistant Klebsiella spp. (CRK) bloodstream infections was conducted in Turkey from June 2018 to June 2019. One hundred eighty-seven patients were recruited. Single OXA-48-like carbapenemases predominated (75%), followed by OXA-48-like/NDM coproducers (16%). OXA-232 constituted 31% of all OXA-48-like carbapenemases and was mainly carried on ST2096. Thirty-day mortality was 44% overall and 51% for ST2096. In the multivariate cox regression analysis, SOFA score and immunosuppression were significant predictors of 30-day mortality and ST2096 had a non-significant effect. All OXA-48-like producers remained susceptible to ceftazidime-avibactam.
Citation - Scopus: 1
Chemical Mechanical Polishing as an Alternative Surface Treatment Technique for Corrosion Prevention of Carbon Steel in an Acidic Medium
(Nature Portfolio, 2025) Ahmed, Mohamed; Ali Al-Timimi, Buthainah; Al-Ali, Maha; Abdullah, Ghassan H.; Khalaf Atiyaha, Safa; Yaseen Ali Aljanabi, Ahmed; Mel, Maizirwan; 01. Atılım University
Chemical mechanical polishing (CMP) has been a standard technique in semiconductor manufacturing for achieving smooth surfaces. CMP utilizes a synergistic interplay of chemical and mechanical interactions to achieve the desired removal rates, selectivity, and ultimately planarity with different substrate materials. In this study, the impact of CMP on the surface properties of steel used in the petroleum industry was examined, with a focus on its corrosion behavior posttreatment. Steel samples were subjected to CMP with and without an oxidizer in a silica-based slurry, and their surface characteristics were compared to those of samples polished mechanically. The addition of an oxidizer to the slurry resulted in increased material removal rates and the formation of an oxide layer on the surface; this phenomenon was not observed in CMP without an oxidizer. However, in mechanical polishing, the action of silicon carbide grains on the steel surface led to an increase in the removal rate but caused a decrease in its corrosion resistance. Compared with other treatments, the oxide layer provided a good protective barrier against corrosion and improved the corrosion resistance of the steel substrate. Based on the results from the practical study, an improvement in the corrosion resistance properties was observed due to the chemical reaction of the oxidizer and the mechanical action of the silica nanoparticles; these results showed the importance of chemical mechanical polishing as an alternative method to reduce the corrosion of steel in acidic environments. Additionally, the effect of hydrogen peroxide in a silica slurry with respect to the wettability, surface roughness, and hardness of steel was examined using contact angle measurements, profilometry, scanning electron microscopy, and microhardness tests.

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