Bishop Çatısı ile İlişkilendirilmiş Hasimoto Yüzeyleri

In this paper, we investigate the Hasimoto surfaces in Euclidean 3- space. Firstly,we investigate the geometric properties of these surfaces in Euclidean 3-space.Especially, we obtain the curvatures of Hasimoto surface according to Bishop frame.Then we give some characterization of parameter curves obtained according to Bishopframe of Hasimoto surfaces.Bu çalışmada Öklidyen 3-uzayındaki Hasimoto yüzeyleri incelenmiştir. İlk olarak, Öklidyen 3-uzayındaki Hasimoto yüzeylerinin geometrik özellikleri incelenmiştir. Özellikle Bishop çatısı ile ilişkilendirilmiş bu yüzeylerin eğrilikleri elde edilmiştir. Daha sonrasında bu yüzeylerin Bishop çatısına göre parametre eğrilerinin bazı karakterizasyonları verilmiştir

Atmospheric Pressure Mass Spectrometry of Single Viruses and Nanoparticles by Nanoelectromechanical Systems

Mass spectrometry of intact nanoparticles and viruses can serve as a potent characterization tool for material science and biophysics. Inaccessible by widespread commercial techniques, the mass of single nanoparticles and viruses (>10MDa) can be readily measured by NEMS (Nanoelectromechanical Systems) based Mass Spectrometry, where charged and isolated analyte particles are generated by Electrospray Ionization (ESI) in air and transported onto the NEMS resonator for capture and detection. However, the applicability of NEMS as a practical solution is hindered by their miniscule surface area, which results in poor limit-of-detection and low capture efficiency values. Another hindrance is the necessity to house the NEMS inside complex vacuum systems, which is required in part to focus analytes towards the miniscule detection surface of the NEMS. Here, we overcome both limitations by integrating an ion lens onto the NEMS chip. The ion lens is composed of a polymer layer, which charges up by receiving part of the ions incoming from the ESI tip and consequently starts to focus the analytes towards an open window aligned with the active area of the NEMS electrostatically. With this integrated system, we have detected the mass of gold and polystyrene nanoparticles under ambient conditions and with two orders-of-magnitude improvement in capture efficiency compared to the state-of-the-art. We then applied this technology to obtain the mass spectrum of SARS-CoV-2 and BoHV-1 virions. With the increase in analytical throughput, the simplicity of the overall setup and the operation capability under ambient conditions, the technique demonstrates that NEMS Mass Spectrometry can be deployed for mass detection of engineered nanoparticles and biological samples efficiently.Comment: 38 pages, 6 figure

Yeni bir örnekseme: mekanik alanındaki çoklu modlar teorisinin elektromanyetik alanında uygulanması

Cataloged from PDF version of article.Thesis (M.S.): Bilkent University, Department of Mechanical, İhsan Doğramacı Bilkent University, 2018.Includes bibliographical references (leaves 75-79).It is crucial to engineer novel detection schemes that can extract information pertinent to the morphological properties of the analytes for widespread usage of lab-on-a-chip technology. Within the scope of this thesis, a novel method that is originated in mechanical domain based on NEMS resonators is adapted to electromagnetic domain with employment of electromagnetic resonators operate in microwave regime. The viability of the proposed method is assessed both by experiments and simulations. The designed micro uidic channel embedded microstrip resonator is driven at its rst two resonant modes simultaneously by a phase-locked loop to detect the analyte passage events within the channel. The attained resolution is 2x108 for both modes at the response time in terms of allan deviation. With the detection scheme we constructed, the location and electrical volume of the microdroplets and cells are obtained. It is shown that the two-mode detection scheme based on microwave resonators can be extended to applications that exploits even higher-order modes to obtain the size, orientation, skewness and permittivity information of the target analytes. Morevover, the framework presented here forms a base for a novel imaging application that can be alternative to optical microscopy.by Mehmet Kelleci.M.S

Cumhuriyet Dönemi’nde metroloji ve Ulusal Metroloji Enstitüsü

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2014.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Öztürk, İbrahim Mert

The Prevalence of Headache in Crohn’s Disease: Single-Center Experience

Objectives. This study is aimed at studying the prevalence and characteristics of different types of headaches in patients with Crohn’s disease. Materials and Methods. 51 patients in Crohn’s disease group (F/M: 26/25) and 51 patients in control group (F/M: 27/24) were involved. Patients in Crohn’s disease group were diagnosed and monitored according to European Crohn’s and Colitis Organization diagnostic criteria. The control group composed of healthy subjects with similar age and sex to Crohn’s disease group. Headache was classified using the International Headache Society II criteria. Results. Headache was reported by 35/51 (68.6%) patients in Crohn’s disease group and 21/51 (41.2%) patients in the control group. The prevalence of headache was statistically high in the group with Crohn’s disease (OR: 3.125 (95% CI: 1.38–7.04); p=0.01). Comparing two groups with respect to their subtypes of headaches resulted in that the tension-type headache was statistically (p=0.008) higher in Crohn’s disease group (26/51) than in the control group (12/51). However, no significant difference was found in the migraine-type headache (p=1). Conclusions. This study indicates that the prevalence of headache is high in patients with Crohn’s disease and most commonly associated with the tension-type headache

Vapor sensing of colorectal cancer biomarkers in isolation by bare and functionalized nanoelectromechanical sensors

Small dimensions and high resonance frequencies render Nanoelectromechanical systems (NEMS) sensitive mass detectors. Mass detection capability can be used to sense chemicals in the gas phase by functionalizing the device, usually with a polymeric film. The performance of NEMS-based gas detectors in breath analysis applications depends crucially on the selectivity between selected functionalization layers and targeted biomarkers. Here, we report the detection of four colorectal cancer biomarkers at parts-per-million concentration levels, when introduced in isolation to the sensor system within a dry nitrogen stream. The biomarkers, 3-methylpentane, cyclohexane, nonanal, and decanal, were then discriminated from each other by using the combined response of three NEMS devices: one bare device, and two devices coated with either poly(ethyleneoxide) or poly(caprolactone). Our results indicate that bare NEMS are more responsive to high molar mass biomarkers, whereas functionalized sensors are more responsive toward more volatile biomarkers. Considering the inherently fast response times and minuscule limits of detection of NEMS devices, the combined response of differentially coated sensors can be used as the main sensing element to identify and distinguish cancer biomarkers in human breath

Assessment of the Appropriateness of Prescriptions in a Geriatric Outpatient Clinic Geriatri Polikliniğinde Reçete Uygunluğunun Değerlendirilmesi

Objectives: Appropriateness of the geriatric outpatients’ medications needs special attention due to risks of falls, fractures, depression, hospital admissions and mortality. This study aimed to identify current practice on medication usage by using the 2nd version of “Screening Tool of Older People’s Potentially Inappropriate Prescriptions” and “Screening Tool to Alert Doctors to Right Treatment” criteria and affecting factors for the Turkish population. Materials and Methods: This cross-sectional study was conducted between September 2015 and May 2016 at a university research and training hospital’s geriatric outpatient clinic. Patients aged ≥65 years and had ≥5 different prescribed medications (considered as polypharmacy) were recruited. The main outcome measure was the frequency of inappropriate medications identified by clinical pharmacist in the outpatient clinic according to the 2nd version of the criterion sets. Results: A total of 700 patients (440 female) were included in this study. According to the results, 316 patients (45.1%) with at least one potentially inappropriate medication and 668 patients (98.3%) with at least one potential prescription omission were detected. Potentially inappropriate medications were associated with the number of medications used per patient [odds ratio (OR): 1.20 p<0.001], living alone (OR: 4.12 p=0.02), and having congestive heart failure (OR: 2.41 p<0.001). Twenty-two (27.5%) out of 80 criteria and 4 (11.8%) out of 34 criteria did not apply to the study population. Conclusion: Detecting inappropriate medications to maintain treatment effectiveness is necessary to provide the optimum therapy. Despite the awareness of polypharmacy in outpatient clinics it is still one of the important causes of inappropriate prescription followed by vaccination rate. Therefore, with the contribution of clinical pharmacist using these available criteria is important, moreover modification of these criteria according to the local needs to be considered to achieve better outcomes

Efficient sensing of single viruses and nanoparticles by nanomechanical sensors integrated with ion lenses

Nanoelectromechanical Systems (NEMS) resonators can be used to detect, weigh and identify single nanoparticles and viruses. Given their small footprint, however, NEMS are plagued by low analyte detection rate since the active sensing cross-sections to capture analyte particles is very small. Here we report on the development of an on-chip focusing lens operating in air and integrated with the NEMS sensor. The integrated system increases the capture efficiency by orders of magnitude, and allows for operation under ambient conditions to measure the mass of nanoparticles and virions. With this system, mass spectrum of nanoparticle samples and mammalian viruses at biologically relevant concentrations can be characterized within less than 30 minutes

Atmospheric pressure mass spectrometry of single viruses and nanoparticles by nanoelectromechanical systems

Mass spectrometry of intact nanoparticles and viruses can serve as a potent characterization tool for material science and biophysics. Inaccessible by widespread commercial techniques, the mass of single nanoparticles and viruses (>10MDa) can be readily measured by nanoelectromechanical systems (NEMS)-based mass spectrometry, where charged and isolated analyte particles are generated by electrospray ionization (ESI) in air and transported onto the NEMS resonator for capture and detection. However, the applicability of NEMS as a practical solution is hindered by their miniscule surface area, which results in poor limit-of-detection and low capture efficiency values. Another hindrance is the necessity to house the NEMS inside complex vacuum systems, which is required in part to focus analytes toward the miniscule detection surface of the NEMS. Here, we overcome both limitations by integrating an ion lens onto the NEMS chip. The ion lens is composed of a polymer layer, which charges up by receiving part of the ions incoming from the ESI tip and consequently starts to focus the analytes toward an open window aligned with the active area of the NEMS electrostatically. With this integrated system, we have detected the mass of gold and polystyrene nanoparticles under ambient conditions and with two orders-of-magnitude improvement in capture efficiency compared to the state-of-the-art. We then applied this technology to obtain the mass spectrum of SARS-CoV-2 and BoHV-1 virions. With the increase in analytical throughput, the simplicity of the overall setup, and the operation capability under ambient conditions, the technique demonstrates that NEMS mass spectrometry can be deployed for mass detection of engineered nanoparticles and biological samples efficiently