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Green Synthesis, Characterisation Of Au And Ag Nanoparticles By Various Bioextracts And Their Usability At Graphite Electrode Modification, Emi̇ne Arslan, Ender Bi̇çer, Eli̇f Sekmen, Semi̇ha Çakir

Turkish Journal of Chemistry

In this study, the biosynthesis of Au and Ag nanoparticles (AuNp and AgNp) with a green chemistry approach was performed by using bioextracts of various fruits and vegetables (Lycopersicon esculentum (LE), Cucumis sativus (CS), Malus domestica (MD), Cucurbita pepo (CP), Apiumgraveolens var. rapaceum (AVR), Prunus cerasifera (PC), Oleraceae var. botrytis (OVB)). In the determination of optimum experimental conditions, the parameters such as the type and concentration of bioextract, concentration of metal ion solutions, the ratio of metal ion solution to bioextract, pH, reaction time and temperature were found to be significant. The characterisation of AuNp and AgNp synthesized by providing …

Intrinsically Fluorescent And Quercetin Loaded Highly Crosslinked Polyphosphazene Nanospheres: Synthesis, Characterization And Fluorescence Properties, Si̇mge Meti̇noğlu Örüm

Turkish Journal of Chemistry

Highly crosslinked, inorganic-organic hybrid and intrinsically fluorescent polyphosphazene nanospheres bearing hydroxyl groups on the surface are facilely generated via a one-pot polycondensation of octachlorocyclotetraphosphazene, fluorescein and quercetin. The resulting nanospheres were characterised by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), X-ray diffraction analysis (XRD) and ultraviolet-visible spectroscopy (UV-vis) techniques. The average diameter of the nanospheres was determined as 379 nm. Also, quercetin which is both a monomer and an anticancer drug was loaded to the nanospheres as 446 mg g-1. The obtained nanospheres possess outstanding disperse ability in both aqueous …

Mil-53(Al) Catalytic Synthesis Of Poly(Ethylene Terephthalate), Ji Wang, Qingyin Wang, Gongying Wang

Turkish Journal of Chemistry

Poly(ethylene terephthalate) (PET) is one of the world's five major engineering plastics and is widely used in various fields. At present, the main catalysts used in the synthesis of PET are antimony, titanium, and aluminum metal compounds. Among them, antimony-based catalysts are poisonous and the titanium-based catalyst products are relatively yellow in hue. The aluminum-based catalyst has the advantages of low price and environmental friendliness, but current research shows that the organoaluminum catalyst has the problem of hydrolysis, and MIL-53 (Al) has good stability and will not affect the environment, so we add a catalyst before the esterification reaction, and …

A Review On The Achievement Of Enzymatic Glycerol Carbonate Production, Selda Aydoğdu, Nurcan Kapucu

Turkish Journal of Chemistry

High energy demand driven by decreasing fossil fuels, and global warming because of the burning of fossil fuels necessitates the utilization of renewable and clean energy. One of these renewable energy sources is biodiesel. The increasing trend of biodiesel over the last 20 years tends to result in increasing glycerol (Gly), which is produced during the biodiesel production in 10% ratio (w/w) as a by-product. Using Gly as raw material is an alternative way to produce bio-based new products such as glycerol carbonate (GlyC). GlyC is a value-added product of Gly/vegetable oil and this product can be used as a …

Investigation Of Boron Nanosized Particles Prepared With Various Surfactants And Chitosan In Terms Of Physical Stability And Cell Viability, Emrah Özakar, Mehmet Semi̇h Bi̇ngöl, Ruki̇ye Sevi̇nç Özakar

Turkish Journal of Chemistry

Nanosuspensions (NS) are one of the new generation drug carrier forms developed to overcome the deficiencies of drugs with poor water solubility or insolubility and are considered to be one of the most successful approaches to formulate compounds in recent years. Boron nitride (BN) is insoluble in water and chemically more stable than carbon, it offers better biological superiority although the application of carbon structures in the biomedical field has increased in recent years. Chitosan is a polymer with excellent processability and biocompatibility thanks to its high dielectric constant. In addition, chitosan has a high affinity for metal ions. This …

Homonuclear Nickel(Ii) Metal-Organic Framework-Type Supramolecule: Adsorption And Emission Properties, Idongesit Mbonu, Olusegun Abiola, Hamzah Bawa

Turkish Journal of Chemistry

Coordination-driven self-assembly of nickel (II) ions with equimolar amounts of 1, 10 phenanthroline, and benzoic acid was used to create homonuclear nickel (II) MOF-type supramolecule. Single crystal X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, photoluminescence measurement, FT-IR, UV-visible spectroscopy, and nitrogen physisorption measurement were used to characterize the compound. The single crystal X-ray diffraction study reveals that the synthesized compound is two-dimensional with pores in the structure. The homonuclear nickel (II) MOF-type supramolecule crystallized in a triclinic crystal system, with space group P-1 (No.2) and unit cell parameters a = 9.2053(4) Ǻ, b = 13.2964(5) Ǻ, c = 15.8998(6) …

Comparison Of Denaturing Agent Effects In Enzymatic N-Glycan Release For Human Plasma N-Glycan Analysis, Haci Mehmet Kayili, Rokia Sakhta, Beki̇r Sali̇h

Turkish Journal of Chemistry

Glycosylation is an essential posttranslational modification observed in the living proteome. Glycosylation profiles in glycoproteins can change in commonly observed diseases such as cancer. Identifying these changes is crucial in discovering new biomarkers for the early diagnosis of cancer. One of the main steps of N-glycan analysis is to release N-glycans from glycoproteins by specific enzymes. The study compares common denaturing agent combinations used in N-glycan release methods. In the study, human plasma was used to test the release methods of N-glycans containing different detergent combinations. The released N-glycans were labeled with the procainamide tag, …

Influence Of Acid Activation On Hydrogen Adsorption Properties Of Analcime-Rich Tuff From Turkey, Meryem Akbelen, Nurgül Özbay

Turkish Journal of Chemistry

In this study, structural, thermal, and hydrogen (H₂) adsorption properties of natural analcime-rich zeolite tuff (A) from Trakya (Turkey) and that of acid-treated forms investigated. Analcime mineral was treated with 0.1, 0.5, 1, 2, and 3 M HCl solutions at 80 °C for 5 h. Differences in structural and thermal behaviors of the analcime samples before and after acid- treatment were examined by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with detector x-ray energy dispersive (SEM-EDX), thermal analysis (TG-DTG-DTA) and nitrogen adsorption methods. Micropore volume, micropore area, and specific surface …

Parameter Effect Quantification For A Phase Change Material-Based Lithium-Ion Battery Thermal Management System, Uğur Morali

Turkish Journal of Chemistry

The influence of discharge rate, ambient temperature, and phase change material on the maximum temperature and the highest temperature difference was investigated. The maximum temperature of the battery was tested with and without phase change material under extreme discharge rates (4C and 5C) and ambient temperatures (310 K and 320 K). Results showed that a phase change material reduced the maximum temperature from 327.94 K to 306.45 K for a 14.6 Ah lithium-ion battery discharged at 5C-rate and 320 K. Quantitatively determined parameter effects revealed that the PCM parameter considerably had a remarkable influence on maximum temperature compared to discharge …

Application Of Srfeo3 Perovskite As Electrode Material For Supercapacitor And Investigation Of Co-Doping Effect On The B-Site, Mohammad Ahangari, Elham Mahmoodi, Nagi̇han Deli̇baş, Jafar Mostafaei, Elnaz Asghari, Aligholi Niaei

Turkish Journal of Chemistry

Energy storage by supercapacitors with short charging time and high power density is one of the types of electrochemical storage systems. Perovskite oxides have been significantly investigated as promising materials for energy storage in electrochemical systems. In this study, three perovskites, SrFeO₃, SrCoO₃, and SrCo_0.5Fe_0.5O₃, were prepared using the sol-gel method and used as supercapacitor electrode materials. In fact, in this research, two consecutive elements (Fe, Co) from the periodic table that differ by one unit in atomic number are placed in the perovskite structure to study their electrochemical properties …

Amin-Modified Graphene Oxide As A Promising Adsorbent For Selective Extraction Of Dexamethasone Adulterant From Herbal Supplements, Mahboob Nemati, Ali Zayer, Samin Hamidi

Turkish Journal of Chemistry

In most cases, herbal supplements found in illegal centers and herbal medicine stores have harmful content that causes irreparable damage to people. As a representative of the green chemistry method, a rapid and efficient dispersive micro solid-phase extraction (D-mSPE) method was applied to extract dexamethasone adulterant from handmade supplements sold as power natural enhancing materials. The quantification of the analyte was performed by high performance liquid chromatography with an ultraviolet detector. Effective parameters on the extraction recovery, including the type and amount of adsorbent, the kind of elution solvent, and the time of extraction and elution, were systematically investigated. The …

Photocatalytic Degradation Of Paracetamol By Semiconductor Oxides Under Uv And Sunlight Illumination, Derman Akşi̇t, Güli̇n Selda Pozan Soylu

Turkish Journal of Chemistry

In this study, photocatalytic degradation of paracetamol (acetaminophen), an analgesic and antipyretic drug, was investigated in using semiconductors under UV-B and sunlight irradiation. Semiconductor materials, Bi₂O₃, ZnO, TiO₂, and ZrO₂, were prepared using simple sol-gel, coprecipitation, and microwave synthesis methods. These photocatalyts were characterized by various spectroscopic and other techniques. As a result of the reactions, 25 ppm paracetamol with Bi₂O₃ and ZnO photocatalyst, total degradation was achieved with UV-B irradiation in 90 min. The results of photocatalytic activities showed that the highest degradation rate was obtained with the …

The Sweet And Embellishing Lycium Arabicum Schweinf. Ex Boiss. Fruit Oil: A Potential Source Of Essential Ω-6 And Ω-9 Fatty Acids, Phytosterols, And Carotenoids, Jawhar Fakhfakh, Marwa Affes, Hazem Jabeur, Mohamed Ayadi, Noureddine Allouche

Turkish Journal of Chemistry

In our current phytochemical investigation on the Tunisian plant Lycium arabicum Schweinf. ex Boiss., we attempted to explore the oil obtained from its fruits. This oil was extracted by cold maceration with ethanol and was analyzed to estimate its sterol and fatty acid content. The physicochemical parameters of the oil were also examined. They were specified in terms of acid value (0.8 ± 0.01 mg KOH g^-1 oil), peroxide value (10.9 ± 0.02 meq O₂ kg^-1 oil), saponification value (162.97 ± 0.03 mg KOH g^-1 oil), chlorophylls (1.011 ± 0.03 mg kg^-1 oil) and carotenoids …

Thermal Versus Photochemical Tautomerization Of Cytosine And Guanine: A Blyp Computational Study Along The Irc Curves, Tsvetina Cherneva, Vassil Delchev

Turkish Journal of Chemistry

We performed a theoretical study, at the BLYP/aug-cc-pVDZ theoretical level, of the mechanisms of H-transfer between biologically relevant tautomers of cytosine and guanine. The analysis of the ground- and excited state energy barriers of the conversions showed that in some cases they are lower as compared to the ground state reactions. The inclusion of one water molecule as a catalyst in the oxo-amino form of cytosine and guanine drastically changes the mechanism of the reactions in the ground as well as in the excited state. For example, the ground state reaction path of cytosine reduces the energy barrier from 165 …

Investigation Of Glycerol Electrooxidation Activity Of Carbon Supported Pdcu Bimetallic Electrocatalyst, Kübranur Ağtoprak, Merve Doğan Özcan, Ayşe Ni̇lgün Akin, Rami̇z Gülteki̇n Akay

Turkish Journal of Chemistry

In this study, Pd/C, Cu/C, and a series of PdCu/C bimetallic electrocatalysts were prepared by microwave-assisted modified polyol method to determine glycerol electrooxidation reaction (GOR) activities. The effect of microwave duration on catalyst structure and GOR activity was investigated on PdCu/C bimetallic catalysts. Also, a commercial Pd/C (com-Pd/C) was used to compare catalytic activities with prepared samples. Electrocatalysts were characterized by using X-ray Diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), and Transmission Electron Microscopy (TEM) analyses. In addition, the activity and stability of electrocatalysts for GOR were examined by using cyclic voltammetry (CV) and chronoamperometry (CA). In XRD …

Prognostic Markers Of Geriatric Patients In The Intensive Care Unit With Acute Hypoxic Respiratory Failure Secondary To Covid-19, Anshul Saxena, Md Ashfaq Ahmed, Zhenwei Zhang

All Publications

Introduction: SARS-CoV-2 (COVID-19) has continued to be a public health emergency, affecting almost 450 million people worldwide, with a disproportionate significant disease burden in the elderly community. Our objective is to provide population specific prognostic markers upon description of demographic factors, clinical characteristics, diagnostic variables, treatment characteristics and outcome variables in critically ill geriatric patients with acute hypoxic respiratory failure due to COVID-19 infection.

Methods: This is a retrospective chart review of 165 patients admitted to a single institution’s medical and cardiovascular intensive care unit between the dates of March 01, 2020 and December 31, 2020. Inclusion criteria was patients …

A Phenomenological Investigation Of Academic Momism: Perceptions Of Female College Faculty’S Role Expectations In High-Stakes Stem Courses, Donna Cempa-Danziger

Theses & Dissertations

This qualitative phenomenological study looked at how female faculty in higher education who teach high-stakes courses may experience a role of academic momism (AM) and how they negotiate their roles and responses within a patriarchal system. Gender bias and prescriptive stereotyping of women as communal may lead female STEM instructors to be perceived more as “academic mothers” (Bernard, 1964) rather than respected academicians. Within higher education institutions, students often perceive their female professors as more concerned about their emotional well-being, nurturing, service oriented, and less academic when compared to male faculty members. The demanding nature of high-stakes courses in STEM-oriented …

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The Two-Echelon Vehicle Routing Problem With Transshipment Nodes And Occasional Drivers: Formulation And Adaptive Large Neighborhood Search Heuristic, Vincent F. Yu, Minh P. K. Nguyen, Kuza Putra, Aldy Gunawan, I. Gusti Bagus Budi Dharma

Research Collection School Of Computing and Information Systems

This research introduces a new variant of the two-echelon vehicle routing problem (2EVRP) called the two-echelon vehicle routing problem with transshipment nodes and occasional drivers (2EVRP-TN-OD). In addition to city freighters in the second-echelon network, a set of occasional drivers (ODs) is available to serve customers. ODs are the basis of a crowd-shipping system in which crowds with planned trips are willing to take detours to deliver packages in exchange for some compensation. To serve customers, ODs collect the assigned packages at either satellite served by first-echelon trucks or transshipment nodes served by city freighters. We formulate this problem as …

Contextual Documentation Referencing On Stack Overflow, Sebastian Baltes, Christoph Treude, Martin P. Robillard

Research Collection School Of Computing and Information Systems

Software engineering is knowledge-intensive and requires software developers to continually search for knowledge, often on community question answering platforms such as Stack Overflow. Such information sharing platforms do not exist in isolation, and part of the evidence that they exist in a broader software documentation ecosystem is the common presence of hyperlinks to other documentation resources found in forum posts. With the goal of helping to improve the information diffusion between Stack Overflow and other documentation resources, we conducted a study to answer the question of how and why documentation is referenced in Stack Overflow threads. We sampled and classified …

An Empirical Study Of Developers' Discussions About Security Challenges Of Different Programming Languages, Roland Croft, Yongzheng Xie, Mansooreh Zahedi, Muhammad Ali Babar, Christoph Treude

Research Collection School Of Computing and Information Systems

In collaborative software development projects, work items are used as a mechanism to coordinate tasks and track shared development work. In this paper, we explore how “tagging,” a lightweight social computing mechanism, is used to communicate matters of concern in the management of development tasks. We present the results from two empirical studies over 36 and 12 months, respectively, on how tagging has been adopted and what role it plays in the development processes of several professional development projects with more than 1,000 developers in total. Our research shows that the tagging mechanism was eagerly adopted by the teams, and …

Novel Secure Outsourcing Of Modular Inversion For Arbitrary And Variable Modulus, Chengliang Tian, Jia Yu, Hanlin Zhang, Haiyang Xue, Cong Wang, Kui Ren

Research Collection School Of Computing and Information Systems

In cryptography and algorithmic number theory, modular inversion is viewed as one of the most common and time-consuming operations. It is hard to be directly accomplished on resource-constrained clients (e.g., mobile devices and IC cards) since modular inversion involves a great amount of operations on large numbers in practice. To address the above problem, this paper proposes a novel unimodular matrix transformation technique to realize secure outsourcing of modular inversion. This technique makes our algorithm achieve several amazing properties. First, to the best of our knowledge, it is the first secure outsourcing computation algorithm that supports arbitrary and variable modulus, …

A Modified Model For The Long-Term Prediction Of Tropospheric Scintillation From Coarse-Resolution Atmospheric Data, James L. Suggs Jr.

Theses

It has been well established that scintillation, or random fades and enhancements of a propagating wave due to turbulence-induced fluctuations of the refractive index, can have deleterious effects on radar and satellite communications systems, especially for frequencies above 10 GHz (3 cm). Kolmogorov theory characterizes turbulence along a given propagation path in terms of the refractive index structure parameter C(superscript 2)(subscript n) . Tropospheric scintillation models are typically driven by C(superscript 2)(subscript n)(z) profiles developed from atmospheric measurements/predictions of pressure, temperature, relative humidity, and wind speed/direction along a given propagation path. In this work, high-resolution distributions of outer-scale, wind shear, …

Math Anxiety And Performance Following Observational Learning And Performance Pressure, Michael G. Duthie

Theses

Past research demonstrated that a variety of factors contribute to the severity of math anxiety and its detriments on math performance. The present study examined the influence of performance pressure, sex, second-hand success or failure of a male or female, and problem difficulty on math anxiety and performance. The design included a 2 (Participant sex: male, female) x 2 (Student actor sex: male, female) x 2 (Video outcome: success, failure) x 2 (Problem difficulty: easy, difficult) x 2 (Pressure: low, high) mixed design. Participants (UAH students, n = 232) were recruited from introductory psychology courses and completed the study via …

Excitation Of The Dominant Transverse Electric Mode Of A Microstrip Patch Antenna Using A Coplanar L-Strip Feeding Technique, Matthew A. Adams

Theses

Microstrip patch antennas are employed in a variety of commercial and military applications due to their versatility, low profile, and ability to be easily fabricated. In this thesis, a microstrip patch antenna is made from artificial magnetic conductor (AMC) unit cells that excite the dominant transverse electric (TE) mode via an L-strip coplanar with the AMC patch layer. Integration of the L-strip into the unit cell layer of the AMC patch and the ground layer of the AMC patch is investigated and full-wave analyzed. To improve gain radiation pattern symmetry about the broadside direction, the AMC patch is shifted laterally …

Applying Data Science And Machine Learning Techniques For Hydrological Applications : Case Study In Cambodia, Biplov Bhandari

Theses

Cambodia suffers from flooding and flash-flooding events every year, and thus better flood management and forecasting are crucial in taking early action. The Streamflow Prediction Tool (SPT) provides forecast discharge 15 days in advance globally. This thesis applies data-driven and Machine Learning (ML) techniques to improve Cambodia’s hydrological applications. Two case studies are presented – the first predicts the river discharge from the water level using time-series information; the second uses the predicted discharge from the first to bias-correct the SPT’s historical reanalysis data using several ML techniques. The historical Bias Correction (BC) is the first step toward the forecasted …

Reinforcement Learning: Low Discrepancy Action Selection For Continuous States And Actions, Jedidiah Lindborg

College of Graduate Studies: Theses & Dissertations

In reinforcement learning the process of selecting an action during the exploration or exploitation stage is difficult to optimize. The purpose of this thesis is to create an action selection process for an agent by employing a low discrepancy action selection (LDAS) method. This should allow the agent to quickly determine the utility of its actions by prioritizing actions that are dissimilar to ones that it has already picked. In this way the learning process should be faster for the agent and result in more optimal policies.

The Ethicality And Political Skill Of Leaders And Subordinate Job Satisfaction: A Study Of Accounting Faculty, Donald L. Ariail

College of Graduate Studies: Theses & Dissertations

Using a sample of 539 accounting faculty teaching in the United States, this study explored perceptions of the ethicality and political skill of their direct supervisors and self-reported levels of job satisfaction. Ethicality was measured with the Ethical Leadership Scale (ELS) and the Behavioral Integrity (BI) Scale. These measures, which were highly correlated, were proxy measures for accounting faculty perceptions of the tone-at-the-top (TATT)—the ethical leadership under which faculty teach and research. The results indicated that while the majority of accounting faculty perceived their direct supervisor as being ethical, about a third (28% BI, 34.8% ELS) of them did not …

Ring Bose–Einstein Condensate Atomtronic Rotation Sensor, Oluwatobi I. Adeniji

College of Graduate Studies: Theses & Dissertations

We propose a design for an atomtronic rotation sensor consisting of an array of Bose– Einstein condensates (BECs) confined in a double–target–array potential. The purpose of the sensor is to measure the rotation speed, Ω_R, of the sensor’s rest frame with respect to the “fixed stars.” The atomtronic system consists of an ultracold gas of sodium atoms compressed, using laser light, into a thin horizontal sheet and subjected to a double–target– array potential within the horizontal plane. A “target” BEC consists of a disk–shaped condensate surrounded by a concentric ring–shaped condensate. A “double–target” BEC is two adjacent target …