Physical Sciences and Mathematics Commons^™

Synthesis Of Functionalized Porphyrins For Application As Soft Materials, Dumrongsak Aryuwananon

Chulalongkorn University Theses and Dissertations (Chula ETD)

The series of functionalized porphyrins was designed and synthesized by varying para-substituents on meso-position of porphyrin ring as ether, ester, and urea with three different long alkyl chains (3-5, 7-9, 11). Afterwards, metalation of porphyrin derivatives by some 3d metals to serve as soft materials, liquid crystal, and axial ligands were introduced to provide spin-crossover property. Each series of functionalized porphyrin derivatives with three different chain lengths (3-5, 7-9, 11) and their Co(II) (3-5a,7-9a), Ni(II) (3-5b,7-9b), and Fe (III) (3-5c,7-9c) complexes were characterized by spectroscopic techniques consisting of NMR, IR, UV-visible and MS. The desired compounds were studied their mesomorphic …

Superhydrophobic Polydimethylsiloxane For Fabrication Of Digital Magnetofluidics, Pakakan Ngernpradab

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, polydimethylsiloxane (PDMS), a well-known material for microfluidic devices, was used to fabricate a digital magnetofluidic device. The use of PDMS material allows for easy fabrication and flexibility. The superhydrophobic property of PDMS surface was easily achieved using a one-pot method by reduction between chloroauric acid and sodium formate. The superhydrophobic property of PDMS surface was investigated using water contact angle (WCA) and contact angle hysteresis, which were found to be 163.9° and 0°, respectively, indicating the superhydrophobic surface. The morphology of gold coated PDMS surface was characterized using a scanning electron microscope (SEM), an X-ray diffractometer (XRD), …

การทำนายพื้นที่เสี่ยงต่อการสึกกร่อนและการกัดกร่อนในอี‍โค‍โน‍ไม‍เซอร์ของหม้อไอน้ำฟลูอิไดซ์เบดแบบหมุนเวียนโดยการจำลองพลศาสตร์ของไหลเชิงคำนวณ, ณัฐวรรณ แสงนวกิจ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้ได้มีการพัฒนาแบบจำลองพลศาสตร์ของไหลของอีโคโนไมเซอร์ของหม้อ‍ไอ‍น้ำ‍ฟลู‍อิ‍ไดซ์เบดแบบหมุนเวียน โดยอาศัยการจำลองพลศาสตร์ของไหลเชิงคำนวณด้วยระเบียบวิธีเชิงตัวเลขแบบไฟไนต์วอลุม ของของไหลหลายวัฏภาคด้วยวิธีการจำลองแบบออย‍เลอ‍เรียน-ออย‍เลอ‍เรียน ในช่วงสภาวะการไหลคงตัว (steady state) เพื่อจำลองอุ‍ทก‍พลศาสตร์และการถ่ายโอนความร้อนภายในอี‍โค‍โน‍ไมเซอร์ ซึ่งจะช่วยในการทำนายพื้นที่เสี่ยงต่อการสึกกร่อนและกัดกร่อนภายในอีโคโนไมเซอร์ ผล‍การคำนวณอุณหภูมิปลายของแก๊สเผาไหม้ได้ถูกนำมาเปรียบเทียบกับข้อมูลสภาวะการทำงานจริงจากบริษัท อินทิเกรทเต็ด รีเสิร์ช เซ็นเตอร์ จำกัด จากผลการทำนายพื้นที่เสี่ยงต่อการกัดกร่อนเนื่องจากการ‍ควบแน่นกรดกำมะถันพบว่า บริเวณผิวท่อใกล้กับทางเข้าน้ำป้อนเข้าสู่ระบบจะเป็นบริเวณที่อุณหภูมิแก๊สเผาไหม้จะมีค่าต่ำ‍ที่สุด ในการทำนายพื้นที่เสี่ยงต่อการกัดกร่อนเนื่องจากการเหนี่ยวนำของสารประกอบคลอไรด์พบว่า การเปลี่ยนแปลงของอุ‍ทก‍พลศาสตร์ของไหลและการถ่ายโอนความร้อนในแต่ละกรณีศึกษา ทำให้การกระจายของชั้นสะสมเถ้าแตกต่างกัน ส่งผลให้พื้นที่เสี่ยงต่อการกัดกร่อนด้วยสาเหตุนี้จะแตกต่างกันในแต่ละกรณี การทำนายพื้นที่เสี่ยงจากความสัมพันธ์ของอัตราการกัดกร่อนกับอุณหภูมิผิวท่อ ผลจากการจำลองพบว่า บริเวณผิวท่อใกล้เคียงกับทางออกของน้ำป้อนจะเป็นบริเวณที่อุณหภูมิผิวท่อสูงที่สุด ซึ่งบริเวณนั้นจะมีความเสี่ยงต่ออัตราการกัดกร่อนเนื่องจากการ‍เหนี่ยวนำของสารประกอบคลอไรด์มากที่สุด และการทำนายพื้นที่เสี่ยงการสึกกร่อนแบบขัด‍สี‍ทางด้านเปลวไฟด้วยการ‍ชนของอนุภาคเถ้าลอยบนผิวท่อ ได้จากการศึกษาความเร็วสูง‍สุดโดยรอบท่อแลกเปลี่ยนความร้อนพบว่า บริเวณใกล้ทางเข้าของน้ำป้อนเข้าระบบจะเสี่ยงต่อการ‍สึก‍กร่อนด้วยการชนของอนุภาคเถ้าด้วยความเร็วสูงที่สุด

การทำนายค่าฝุ่น Pm2.5 ทั้งในเชิงแผนที่และเชิงเวลาด้วยเทคนิคการเรียนรู้เชิงลึก, ณัฏฐ์ ศิริสัมพันธ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

PM2.5 เป็นอนุภาคขนาดเล็กที่มีส่วนทำให้เกิดปัญหามลพิษทางอากาศในประเทศไทย การหายใจนำฝุ่น PM2.5 เข้าไปสามารถทำให้เกิดปัญหาสุขภาพตามมาได้ เช่น โรคทางเดินหายใจและโรคหัวใจเสื่อมสภาพ รวมถึงเพิ่มความเสี่ยงต่อการเสียชีวิตก่อนวัยอันควร งานวิจัยนี้เสนอแบบจำลองที่ใช้การเรียนรู้เชิงลึกเพื่อทำนายค่าฝุ่น PM2.5 ในระดับประเทศซึ่งเป็นการทำนายทั้งในเชิงพื้นที่และเวลา โดยแบบจำลองที่นำเสนอมีชื่อว่า SimVP-CFLL-ML มีพื้นฐานมาจากแบบจำลองการทำนายวิดีโอที่เรียกว่า "SimVP" และเพื่อเพิ่มประสิทธิภาพในการทำนายค่าฝุ่น PM2.5 ในช่วงที่มีค่าฝุ่นสูง SimVP ได้มีการพัฒนาเพิ่มเติมสองประการ คือ 1.Cross-Feature Learning Layer (CFLL) ซึ่งใช้ 1x1 convolution layer เพื่อเรียนรู้ความสัมพันธ์ของคุณลักษณะและ 2.Masking Layer (ML) ซึ่งใช้สำหรับคำนวณค่าลอสเฉพาะส่วนที่สำคัญที่ต้องการทำนาย โดยในที่นี้คือส่วนที่เป็นประเทศไทย การทดลองดำเนินการโดยใช้ข้อมูลที่เก็บรวบรวมจากกรมควบคุมมลพิษของประเทศไทยและโครงการ Sensor For All (SFA) ผลการทดลองแสดงให้เห็นว่าแบบจำลองของเราเหนือกว่าแบบจำลองพื้นฐานทั้งหมด โดยเฉพาะในกรณีที่ต้องการจำแนกช่วงที่ค่าฝุ่นมีค่าสูง แบบจำลองของเราได้ผลลัพธ์ค่าคะแนน F1 สูงกว่าแบบจำลองพื้นฐานที่ดีที่สุดถึง 3.51%

ระบบสนับสนุนการจัดเก็บและวิเคราะห์ข้อมูลลำดับซ้ำเรียงต่อเนื่องแบบสั้นสำหรับนิติวิทยาศาสตร์, ณัฏฐชัย กุลธรรมนิตย์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ลำดับซ้ำเรียงต่อเนื่องแบบสั้น (Short Tandem Repeat) หรือเอสทีอาร์ (STR) เป็นลำดับที่ซ้ำกันเป็นชุด ๆ ที่พบได้ในจีโนม (Genome) ของมนุษย์และมีประโยชน์มากในนิติวิทยาศาสตร์ เช่น การยืนยันตัวบุคคล การหาความสัมพันธ์ทางเครือญาติ เทคโนโลยีการลำดับเบสยุคใหม่ (Next-Generaton Sequencing: NGS) เช่น ForenSeq Signature Prep สามารถหาลำดับ STRs และให้ข้อมูลเชิงลึกเกี่ยวกับโครงสร้างประชากรได้ ถึงแม้ว่าเอสทีอาร์ที่ได้จากเทคโนโลยีนี้จะมีประโยชน์มากมาย แต่ไม่มีแพลตฟอร์มซอฟต์แวร์โอเพ่นซอร์สใดที่รวมการจัดการและการวิเคราะห์ข้อมูลของเอสทีอาร์ไว้ในแพลตฟอร์มเดียว ผู้ใช้งานอาจต้องใช้หลายโปรแกรมในการวิเคราะห์ข้อมูลเอสทีอาร์ จากนั้นรวบรวมผลลัพธ์ลงในฐานข้อมูลแยกหรือโฟลเดอร์ระบบไฟล์ เพื่อแก้ไขปัญหาดังกล่าว ระบบที่นำเสนอ STRategy เป็นเว็บแอพพลิเคชันที่มีระบบการจัดการและวิเคราะห์ข้อมูลเอสทีอาร์ โดย STRategy อนุญาตให้ผู้ใช้งานเก็บข้อมูลลงฐานข้อมูลหลังจากนั้นระบบจะวิเคราะห์และแสดงผลข้อมูลโดยอัตโนมัติ ระบบนี้ถูกออกแบบให้ใช้ในองค์กรหรือห้องปฏิบัติการ จึงมีระบบการกำหนดสิทธิผู้ใช้ระบบตามบทบาท (Role Based Access Control) เพื่อให้ผู้ใช้งานเข้าถึงข้อมูลตามสิทธิของแต่ละบุคคลเท่านั้น ระบบถูกออกแบบให้มีความยืดหยุ่นสูง และได้ปฏิบัติตามแนวคิดสถาปัตยกรรม 3-เลเยอร์ หลักการออกแบบโปรแกรมเชิงวัตถุ รวมถึงมีการใช้แบบรูป (Design patterns) ต่าง ๆ เพื่อรองรับการเพิ่มโมดูลการวิเคราะห์และโมดูลการแสดงผล รวมถึงการพัฒนาต่อยอดได้ง่ายในอนาคต

Unique Features Of Alarmone Metabolism In Clostridioides Difficile, Asia Poudel, Astha Pokhrel, Adenrele Oludiran, Estevan J. Coronado, Kwincy Alleyne, Marrett M. Gilfus, Raj K. Gurung, Surya B. Adhikari, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The “magic spot” alarmones (pp)pGpp, previously implicated in Clostridioides difficile antibiotic survival, are synthesized by the RelA-SpoT homolog (RSH) of C. difficile (RSH_Cd) and RelQ_Cd. These enzymes are transcriptionally activated by diverse environmental stresses. RSH_Cd has previously been reported to synthesize ppGpp, but in this study, we found that both clostridial enzymes exclusively synthesize pGpp. While direct synthesis of pGpp from a GMP substrate, and (p)ppGpp hydrolysis into pGpp by NUDIX hydrolases, have previously been reported, there is no precedent for a bacterium synthesizing pGpp exclusively. Hydrolysis of the 5′ phosphate or pyrophosphate from GDP …

Microbial Labilization And Diversification Of Pyrogenic Dissolved Organic Matter, Aleksandar I. Goranov, Andrew S. Wozniak, Kyle W. Bostick, Andrew R. Zimmerman, Siddhartha Mitra, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrence of wildfires around the world, interest in the chemistry of pyrogenic organic matter (pyOM) and its fate in the environment has increased. Upon leaching from soils by rain events, significant amounts of dissolved pyOM (pyDOM) enter the aquatic environment and interact with microbial communities that are essential for cycling organic matter within the different biogeochemical cycles. To evaluate the biodegradability of pyDOM, aqueous extracts of laboratory-produced biochars were incubated with soil microbes, and the molecular changes to the composition of pyDOM were probed using ultrahigh-resolution mass spectrometry (Fourier transform–ion cyclotron resonance–mass spectrometry). Given that solar irradiation …

Visible Opacity Of M Dwarfs And Hot Jupiters: The Tio B³Π-X³Δ Band System, W. Doug Cameron, Peter Bernath

Chemistry & Biochemistry Faculty Publications

The TiO B³Π−X³Δ electronic transition (𝛾' system) is an important opacity source in the atmospheres of M dwarfs and hot Jupiter exoplanets. The 0–0, 1–0, and 2–1 bands of the B³Π−X³Δ band system have been analyzed using a TiO emission spectrum recorded at the McMath-Pierce Solar Telescope, operated by the National Solar Observatory at Kitt Peak, Arizona. Improved spectroscopic and equilibrium constants were determined. Line strengths were calculated from an ab initio transition-dipole moment function scaled using an experimental lifetime. A new line list for v' = 0–2 and v′′ = 0–4 …

Marcadores Moleculares Subrogados A La Repelencia Al Agua En Suelos Afectados Por El Fuego, Nicasio T. Jiménez-Morillo, Gonzalo Almendros, Nuno Guiomar, Ana Z. Miller, Cristina Barrocas-Dias, José M. De La Rosa, Patrick G. Hatcher, José A. González-Pérez

Chemistry & Biochemistry Faculty Publications

Soil water repellency (SWR) is often attributed to the accumulation of hydrophobic organic compounds, mainly lipids. Nonetheless, lipid extraction not always suppress SWR and unextractable soil constituents may be related with residual SWR. Burnt (B) and unburnt (UB) soils (Doñana National Park, Huelva) under two vegetations (cork oak and heather) and two soil fractions, coarse (1–2 mm) and fine (

Pd-Based Photocatalysts For Heck C-C Cross-Coupling Reactions, Suha Ali Alshehri

Masters Theses

Heck C-C cross-coupling reaction has been widely employed in synthetic organic chemistry because of its high efficiency and simplicity, however the conventional Heck C-C cross-coupling reaction conditions involve the use of an expensive toxicant phosphine-ligated palladium complexes, and high temperature. To address these drawbacks, a highly efficient, homogeneous photocatalyst based on BODIPY for the Heck C-C cross-coupling reactions of aryl iodide and methyl acrylate in DMF solvent under inert conditions has been developed. The 4-Py-BDP-Pd, 3-Py-BDP-Pd and, 2-Py-BOD-Pd catalysts were synthesized and purified using column chromatography. The optical properties of products and intermediates were studied by UV/vis absorption and fluorescence …

Applying Intensity-Based Methods To Disentangle Microwave Spectra Of Complex Mixtures: Analysis Of Weakly Bound Clusters Of 1,1-Difluoroethylene/Co2, Hannah Fino

Masters Theses

Microwave spectroscopy is used to study the solvent-solute interactions between molecules of CO₂ and fluoroethylenes by analyzing the formation of weakly-bound clusters in a gaseous mixture. One of the challenges to analyzing microwave spectra obtained for these weakly-bound species is that spectra for individual clusters are mixed together in an original complex spectrum. This prompts development of automated techniques that could separate complex data into subsets of related data to be more easily analyzed.

The techniques developed in this work are founded on intensity-based analyses, following the work of Dr. Robert Field on Extended Cross Correlation (XCC). The XCC …

A Study On Developing Novel Methods For Relation Extraction, Darshini Mahendran

Theses and Dissertations

Relation Extraction (RE) is a task of Natural Language Processing (NLP) to detect and classify the relations between two entities. Relation extraction in the biomedical and scientific literature domain is challenging as text can contain multiple pairs of entities in the same instance. During the course of this research, we developed an RE framework (RelEx), which consists of five main RE paradigms: rule-based, machine learning-based, Convolutional Neural Network (CNN)-based, Bidirectional Encoder Representations from Transformers (BERT)-based, and Graph Convolutional Networks (GCNs)-based approaches. RelEx's rule-based approach uses co-location information of the entities to determine whether a relation exists between a selected entity …

Progress Towards Next Generation Modulators Of Ctbp's Oncogenic Effects, Jacqueline L. West

Theses and Dissertations

Human C-terminal binding proteins (CtBP1 and CtBP2) are transcriptional coregulators of multiple genes in the human genome, including tumor suppressor genes (e.g., Bik, PTEN, BRCA1, and E-cadherin) as well as oncogenes (e.g. MDR1 and Tiam1). Both homologues of CtBP are overexpressed in many types of cancer, including breast cancer (92%), ovarian cancer (83%), colorectal cancer (64%), hepatocellular carcinoma (60%), gastric cancer, prostate cancer, and pancreatic adenocarcinoma. Further, expression levels of CtBP correlate with worse prognostic outcomes and more aggressive tumor features because it promotes proliferation, epithelial-mesenchymal transition, and cancer stem cell self-renewal activity.

Our laboratory has identified a lead inhibitor …

Development Of Novel Intracavitary Intensity Modulated Brachytherapy Applicators For Optimizing The Target Coverage In Gynecologic Malignancies, Monte Carlo Simulation Dosimetry, Moeen Meftahi

Theses and Dissertations

Gynecologic brachytherapy (GYN-BT) is essential for treating cervical and endometrial cancers, the most prevalent female reproductive cancers. This technique enables high radiation doses to a target with rapid dose fall-off to protect adjacent healthy organs. This dissertation aims to address some of the limitations of intracavitary GYN-BT using an intensity modulated brachytherapy (IMBT) technique and Monte Carlo (MC) simulations.

First, a novel non-invasive shielded vaginal cylinder (VC) applicator was designed to provide optimized radiation coverage for the target volume at vaginal apex, site of most recurrences without BT, for endometrial cancer BT. Physical limitations of current applicators and their resulting …

Approximating Bayesian Optimal Sequential Designs Using Gaussian Process Models Indexed On Belief States, Joseph Burris

Theses and Dissertations

Fully sequential optimal Bayesian experimentation can offer greater utility than both traditional Bayesian designs and greedy sequential methods, but practically cannot be solved due to numerical complexity and continuous outcome spaces. Approximate solutions can be found via approximate dynamic programming, but rely on surrogate models of the expected utility at each trial of the experiment with hand-chosen features or use methods which ignore the underlying geometry of the space of probability distributions. We propose the use of Gaussian process models indexed on the belief states visited in experimentation to provide utility-agnostic surrogate models for approximating Bayesian optimal sequential designs which …

Universal Design In Bci: Deep Learning Approaches For Adaptive Speech Brain-Computer Interfaces, Srdjan Lesaja

Theses and Dissertations

In the last two decades, there have been many breakthrough advancements in non-invasive and invasive brain-computer interface (BCI) systems. However, the majority of BCI model designs still follow a paradigm whereby neural signals are preprocessed and task-related features extracted using static, and generally customized, data-independent designs. Such BCI designs commonly optimize narrow task performance over generalizability, adaptability, and robustness, which is not well suited to meeting individual user needs. If one day BCIs are to be capable of decoding our higher-order cognitive commands and conceptual maps, their designs will need to be adaptive architectures that will evolve and grow in …

The Impact Of A Gencyber Camp On In-Service Teachers’ Tpack, Kevin M. Thomas, Jessica Ivy, Kristin Cook, Robert R. Kelley

Journal of Cybersecurity Education, Research and Practice

The purpose of this study was to examine the impact of a GenCyber camp curriculum on teachers’ technology, pedagogy, and content knowledge (TPACK). The camp was designed to engage participants in developing the knowledge and skills to incorporate GenCyber Cybersecurity First Principles and GenCyber Cybersecurity Concepts (GenCyber, 2019) into their curriculums. Participants (37 middle and high school teachers from a variety of disciplines) attended one of two weeklong camps held at a Midwestern liberal arts university. Using the TPACK Self-Reflection and TPACK Self-Assessment Surveys, pre- and post-camp data were collected from participants. Findings indicate that participants demonstrated an increase in …

Toward A Student-Ready Cybersecurity Program: Findings From A Survey Of Stem-Students, Lora Pitman, Brian K. Payne, Tancy Vandecar-Burdin, Lenora Thorbjornsen

Journal of Cybersecurity Education, Research and Practice

As the number of available cybersecurity jobs continues to grow, colleges strive to offer to their cybersecurity students an environment which will make them sufficiently prepared to enter the workforce after graduation. This paper explores the academic and professional needs of STEM-students in various higher education institutions across Virginia and how cybersecurity programs can cater to these needs. It also seeks to propose an evidence-based approach for improving the existing cybersecurity programs so that they can become more inclusive and student-ready. A survey of 251 college students in four higher-education institutions in Virginia showed that while there are common patterns …

Github Repositories With Links To Academic Papers: Public Access, Traceability, And Evolution, Supatsara Wattanakriengkrai, Bodin Chinthanet, Hideaki Hata, Raula Kula, Christoph Treude, Jin Guo, Kenichi Matsumoto

Research Collection School Of Computing and Information Systems

Traceability between published scientific breakthroughs and their implementation is essential, especially in the case of open-source scientific software which implements bleeding-edge science in its code. However, aligning the link between GitHub repositories and academic papers can prove difficult, and the current practice of establishing and maintaining such links remains unknown. This paper investigates the role of academic paper references contained in these repositories. We conduct a large-scale study of 20 thousand GitHub repositories that make references to academic papers. We use a mixed-methods approach to identify public access, traceability and evolutionary aspects of the links. Although referencing a paper is …

Preparation Of Surface Plasmon Resonance-Based Nanosensor For Curcumin Detection, Şebnem Çikrik, Duygu Çi̇men, Ni̇lay Bereli̇ Deni̇zli̇, Adi̇l Deni̇zli̇

Turkish Journal of Chemistry

In this study, the curcumin imprinted and the non-imprinted poly(2-hydroxyethyl methacrylate-N-methacryloyl-Ltryptophan) (poly(HEMA-MATrp)) nanoparticle based surface plasmon resonance (SPR) nanosensors were prepared for the detection of curcumin and characterized by zeta-size analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. After, the curcumin imprinted and the non-imprinted nanoparticles are attached on the surface of SPR chips. The curcumin imprinted and the non-imprinted SPR nanosensors are characterized by using atomic force microscope, ellipsometer, and contact angle measurements. Kinetic studies were carried out with curcumin aqueous solution at a concentration range of 0.01-150 mg/L using the curcumin imprinted and the non-imprinted SPR nanosensors. …

Synthesis Of Modified Nanocomposite Material And Its Use On Removal Of Cesium Fromaqueous Media, Bi̇lal Çeti̇n, Mustafa Özcan, Bektaş Karakelle

Turkish Journal of Chemistry

A nanocomposite containing Fe3O4, chitosan (Ch), and hexacyanoferrate (HCF) was synthesized in the form of powder. The physicochemical properties of this nanocomposite are determined using different techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). The existence of Cs (Cs) ions onto the surface of the nanocomposite was verified by dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed that the nanocomposite was well coordinated. The batch technique was applied to evaluate the influences of initial pH value, temperature, contact time, shaking rate, initial Cs concentration, and competing cations on the efficiency of Cs …

Investigation Of Antibacterial And Photocatalytic Efficiency Of Green Zno Nanoparticles That Synthesized With Celosia Cristata Flower Extract, Mahmure Özgür, Özgür Duygulu, Melda Altikatoğlu Yapaöz

Turkish Journal of Chemistry

Increasing interest in green chemistry has led scientists to an environmentally friendly nanoparticle synthesis approach that has many advantages, such as simple, affordable and versatility for a wide range of commercial production. In this study, green synthesis of zinc oxide nanoparticles (ZnO NPs), which is widely researched in the field of nanotechnology, was performed under different conditions (volume ratio of CC flower extract to Zn(CH3COO)2 solution, time, pH and temperature) using the aqueous extract of Amarant (Celosia cristata L., CC, cockscome) plant flowers. Produced ZnO NPs were characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron …

The Study Of Fe3o4@Sio2-Nh2 Nano-Magnetic Composite Modified By Glutaraldehyde To Immobilized Penicillin G Acylase, Monier Alhadi Abdelrahman Mohammed, Zhenbin Chen, Ke Li, Boyuan Zhang

Turkish Journal of Chemistry

Preparation of biocatalyst dependent on immobilized penicillin G acylase (PGA) was of substantial importance for proteomic research, organic synthesis, and industrial applications. Herein, we developed an easy method for nano-magnetic composite to immobilize PGA. Fe3O4 nano-magnetic particles were co-precipitated with Fe3+ and Fe2+ in an ammonia solution (NH3) and treated with silicon dioxide (SiO2), which was developed using the sol-gel process. Thereafter, 3-aminopropyltriethoxysilane (APTES) was used to modify the silica-coated Fe3O4, which would result in the attachment of the primary amine groups to the particle surface. After that, the attachment of primary amine group was reacted with glutaraldehyde (Glu) to …

Supramolecular Solvent-Based Microextraction For The Preconcentration Of Pb2+ Andcd2+ Prior To Spectrophotometric Detection, Huma Zafar, Faheem Shah, Rafaqat Ali Khan, Asad Muhammad Khan, Jan Nisar, Bushra Ismail

Turkish Journal of Chemistry

Supramolecular solvent-based dispersive liquid-liquid microextraction technique has been developed as a preconcentration tool for the determination of trace level of Pb2+ and Cd2+. Dodecanol dispersed in tetrahydrofuran has been utilized as a supramolecular-solvent system for the extraction of analytes prior to their quantitative determination with graphite furnace atomic absorption spectrophotometer. Both Pb2+ and Cd2+, which were efficiently extracted by supramolecular solvent system, were complexed with dithizone followed by the addition of supramolecular solvent. The experimental variables that could possibly influence the extraction efficiency, i.e. pH value, temperature, sample volume, centrifugation time, rate of centrifugation, ionic strength, etc. were subjected to …

Selective Adsorption Of Acidic Gases From Ternary Mixture By Acetate- And Sulfonate-Based Ionic Liquids At Molecular Level, Sadi̇ye Veli̇oğlu

Turkish Journal of Chemistry

This paper attempts to elucidate the competitive adsorption mechanism of thin films of ionic liquids (ILs) on the surface of porous materials for acidic gases at a molecular level in order to design a proper material for the diminishment of gas emissions. Thin film 1-butyl-3-methylimidazalium ([BMIM]+) cation-based IL systems composed of four different anions such as [CH3CO2]- and [CF3CO2]- (acetate-based), and [CH3SO3]- and [CF3SO3]- (sulfonate-based) are created in contact with the gas phase containing ternary H2S/CO2/CH4:1/25/74 mixture. To define gas adsorption performance at gas?liquid interface and bulk liquid phase, classical molecular dynamics simulations are carried out. Adsorption of acidic gases …

Recycled Human Hair-Derived Activated Carbon For Energy-Related Applications, Oğuzhan Kotan, Hati̇ce Bayrakçeken

Turkish Journal of Chemistry

Activated carbon, having high surface area and porosity, is a carbonaceous material that comes from organic main sources. In this work, activated carbon materials were produced from human hair that belongs to people who can be classified into two age groups (0-18 or 18-40 years). Activated carbons were characterized by nitrogen adsorption/desorption isotherms (BET), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and elemental analysis techniques. Capacitances of the synthesized materials were determined by using cyclic voltammetry (CV). Characterization results showed that the structural properties of activated carbon materials and capacitance values are changed …

Capillary Zone Electrophoresis As A Quality Assessment Tool Of Paracetamol And Phenylephrine Hydrochloride In Presence Of Paracetamol Impurities, Joliana Farid, Nadia Mostafa, Yasmin Fayez, Hebatallah Essam

Turkish Journal of Chemistry

The combination of paracetamol (PAR) and phenylephrine HCl (PHE) is a common pharmaceutical combination intended to manage symptoms of every day cold. Since paracetamol is susceptible to degradation or some manufacturing-related impurities, its stability should be monitored continuously. The developed method in this study for the determination of PAR and PHE in presence of PAR impurities is considered a quality assessment tool especially when PAR impurities can be quantitatively determined. A capillary zone electrophoresis (CZE) method was optimized and validated for simultaneous determination of PAR and PHE in presence of PAR impurities namely, p-Aminophenol (PAP), p-Nitrophenol (PNP), Acetanilide (ACT) and …

Dft / Tddft Insights Into Excited State Intra-Molecular Hydrogen Atom Transfer Mechanism In Liqcoumarin: An Efp1 Study, Kandigowda Jagadeesha, Yelechakanahally Lingaraju Ramu, Mariyappa Ramegowda

Turkish Journal of Chemistry

The theoretical calculations were carried out on Liqcoumarin (LC) and its water complex LC+(H20)4-[LCH] at the ground (S0) / first excited states (S1) by employing density functional theory (DFT) / state specific time-dependent density functional theory (SS-TDDFT). In LC and LCH, there is an intra-molecular hydrogen bond between hydroxyl group and acetyl group along with four inter-molecular hydrogen bonds in the hydrated molecule. The computational studies of molecular structural parameters, electrostatic potential, NBO analysis, molecular orbital's, and UV-Vis spectra of both molecules under polar solvents were explored by B3LYP / 6-31G (d,p) / PCM / EFP1 method. The intra-molecular hydrogen …

Synthesis Of Benzoyl Hydrazones Having 4-Hydroxy-3,5-Dimethoxy Phenyl Ring, Theirbiological Activities, And Molecular Modeling Studies On Enzyme Inhibition Activities, Bedri̇ye Seda Kurşun Aktar, Yusuf Sicak, Gi̇zem Tatar, Emi̇ne Elçi̇n Emre

Turkish Journal of Chemistry

Hydrazone compounds have high capacity in terms of antioxidant activity and enzyme inhibition activities such as anticholinesterase, tyrosinase, and urease. In this study, benzoyl hydrazones compounds (7a-7m) were synthesized starting from 3,5-dimethoxy-4-hydroxybenzaldehyde. Antioxidant activity of the synthesized compounds was evaluated. In the β-carotene-linoleic acid and ABTS cation radical scavenging activities, compounds 7j, 7e, and 7m stood out as the most active compounds, respectively. In the anticholinesterase enzyme inhibition activity results, compound 7f exhibited the best activity against AChE and BChE enzymes in the synthesis series. In addition, molecular docking analysis was performed to understand the inhibition mechanism of the synthesized …

Phytochemical Composition And Pharmacological Activities Of Teucrium Polium L. Collected From Eastern Turkey, Gi̇zem Gülsoy Toplan, Fati̇h Göger, Turgut Taşkin, Gülay Ecevi̇t Genç, Ayşe Ci̇vaş, Gökalp İşcan, Mi̇ne Kürkçüoğlu, Afi̇fe Mat, Kemal Hüsnü Can Başer

Turkish Journal of Chemistry

Teucrium species that belong to the family Lamiaceae have been traditionally used for their medicinal properties. T. polium is one the most widespread members of the genus for its use in the treatment of several diseases. In this study, the essential oil and phenolic composition of the aerial parts from T. polium were assessed by GC-FID, GC/MS, and LC-MS/MS as well as for its total phenolic content. Several extracts such as n-hexane, chloroform, methanol, and infusion were prepared and their antimicrobial, antioxidant, and also acetylcholinesterase activities were studied. According to GC/MS results, β -caryophyllene (8.8%), t-cadinol (6.2%), (E)-nerolidol (5%), α …