Physical Sciences and Mathematics Commons^™

Synthesis And Catalytic Behaviors Of Sub-10nm Platinum Group Metal Nanocatalysts, Zixin Wang

Theses and Dissertations

Nanoparticles of platinum group elements(Pd, Pt, Rh, Ir, Ru and Os) exhibit intriguing catalytic behaviors that are sensitively dependent upon their particle dimensions, chemical compositions, and surface structures. Platinum group elementbased nanomaterials have been widely utilized for catalyzing a series of important chemical reactions, producing over 90% of chemicals and fuels and accounting for 35% of the world's GDP globally. Reducing the overall particle sizes of the catalysts to the sub-10 nm size regime not only effectively mitigates the cost issues associated with the noble metal-based materials, but also remarkably modifies the surface atomic coordinations and the electronic band energies, …

Small Molecule Activation By Dirhenium Carbonyl Complexes, Meenal Kaushal

Theses and Dissertations

The background of small molecule activation is discussed in Chapter 1. Carbon-hydrogen (C-H) bond activation and carbon-carbon (C-C) bond formation using transition metal complexes are explained using examples from the literature. It also includes the previous work done by Dr. Adams’ lab on C-H bond activation and zwitterions in metal carbonyl complexes.

The reaction of Re₂(CO)₈(µ-C₆H₅)(µ-H) with vinyl acetate yielding three new products has been discussed in Chapter 2. One of the products Re₃(CO)₁₃(µ-η² -C₂H₃), 2.3 further reacts with I₂ resulting in …

Disinfection Byproducts In Wastewater, Swimming Pools, And Tea: Identification, Quantification, And Drivers Of Toxicity, Caroline O. Granger

Theses and Dissertations

Drinking water disinfection is considered one of the greatest scientific achievements of the 20th Century because it significantly reduced the number of deaths related to waterborne diseases. However, in 1974 J.J. Rook discovered that chlorine, a commonly used disinfectant, can react with natural organic matter to form disinfection byproducts (DBPs). Since then, more than 700 DBPs have been identified, with several epidemiological and toxicological studies linking DBPs to several adverse health effects such as bladder and colorectal cancer, adverse birth outcomes, and asthma. Due to their ubiquity in disinfected water and their adverse health effects, studying the formation and identifying …

Mechanisms And Impact Of Hypoxia Regulated Inhibins In Cancer, Ben Allen Horst

Theses and Dissertations

Inhibins are heterodimeric ligands within the TGFβ superfamily, comprised of an α-subunit (INHA) and a β-subunit (either INHBA or INHBB) with emergent roles in cancer. Inhibins are biomarkers of disease burden and prognosis in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Previously, we found inhibin promotes angiogenesis in ovarian cancer however no mechanism of regulation for inhibin expression in cancer has been established. Hypoxia, a driver of tumor growth and metastasis, regulates angiogenic pathways that are targets for vessel normalization and ovarian cancer management. …

Crystal Growth Of Inorganic Halides And Oxide-Halides For Scintillation Applications And Radiation Detection, Gyanendra B. Ayer

Theses and Dissertations

Scintillators, materials which emit light when struck by high energy X-rays and y- rays, are extensively used in various fields including medical imaging, computed tomography, high-energy physics, and more recently in homeland security for the prevention of nuclear and radiological terrorism. While comparing with the traditional scintillators, which have long-term instability, high synthetic cost, toxicity, and hygroscopicity issues, metal halides have been reported to exhibit effective excitonic radioluminescence and greatly contribute in the field of scintillating applications and radiation detection. Currently, the mixed-anion oxide-fluorides have emerged as a prospective new class of scintillators, in which the mixed oxide-fluoride environment …

Characterization Of Pyrrolidinyl-Hexahydro-Pyranopiperazines As A Novel Kappa Opioid Receptor Agonist Scaffold, Brian Reed, Michael Miller, Mayako Michino, Eduardo R. Butelman, Ariel Ben-Ezra, Philip Pikus, Michelle Morochnik, Yuli Kim, Amy Ripka, Joseph Vacca, Mary Jeanne Kreek

Faculty Works: BCES (1999-2023)

The kappa agonist structure–activity relationship around the novel, pyrrolidinyl substituted pyranopiperazine scaffold was developed. More specifically, the dichloroPhenylAcetamide-Pyrrolidinyl-PyranoPiperazine (PAPPP) core A was the focus of our work. The modulation of kappa receptor potency/G-protein activation and arrestin recruitment with respect to changes of the piperazine R group in A was demonstrated. Reduced β2-arrestin recruitment and differential G-protein bias were observed for select analogues. To better understand the subtlety in receptor signaling, analogues were profiled as the resolved enantiomers. To determine in vivo target engagement, a subset of compounds was tested in mice for stimulation of serum prolactin, a neuroendocrine biomarker of …

Probing The Stability And Solution Processability Of Metal Chalcogenide Semiconducting Materials, Mengwen Yan

Legacy Theses & Dissertations (2009 - 2024)

Metal chalcogenide (MCh) semiconductors have long research history due to their earth abundance, easy synthesizability, and accessible band gap tunability. People have realized their functionality as p-type semiconductors that provide good hole mobility and conductivity within the materials. However, MChs have easier reaction pathway with gas molecules (H2O and O2) compared to other semiconductors such as metal oxides. Also, poor solution processability of all MChs make low-cost thin film fabrication methods hard to achieve. In this thesis, we target to understand both the chemical stability and solution processability of MCh materials. ZnSe based inorganic organic layered hybrids (LHs) were exfoliated …

Evaluation Of Silver Nanoparticles Attached To Methylene Blue As An Antimicrobial Agent And Its Cytotoxicity, Somon Hakimov

Masters Theses & Specialist Projects

Antibiotics resistance is considered as one of the greatest public health challenges of our time. In this work, we have synthesized silver nanoparticles (Ag NPs) using pulsed liquid ablation in different medium of growth and later combined with methylene blue (MB) to evaluate its potential as an effective photodynamic therapy agent. Ag NPs were synthesized by pulsed laser ablation technique in Polyvinylpyrrolidone (PVP), citrate, and Polyvinyl alcohol (PVA). The Ag NPs were characterized using transmission electron microscopy (TEM), UV-Visible (UV-Vis), and photoluminescence (PL) spectra. Next, Ag NPs were coupled with MB and used to deactivate the Gram-negative bacteria, Escherichia coli …

Sol-Gel Synthesis And Spectroscopic Characterization Of Titanium Dioxide Doped With Copper And Iron, Erin L. Jacoski

Chemistry Senior Theses

A source of bioavailable iron in open oceans stems from aerosols, increasing phytoplankton growth and the sequestration of atmospheric carbon dioxide. These aerosols contain semiconductors, like titanium dioxide, which is known to increase the bioavailability and can trigger photoreduction of Fe3+. Recently, it is suspected that other metals in the aerosols also influence the release of iron. In this work, the effects of doping with iron and copper on the physical characteristics of titanium dioxide nanoparticles, since the photocatalytic potential of titanium dioxide depends on its structure and metal content (anatase vs. rutile), were explored. Titanium dioxide nanoparticles were prepared …

Method Of Hybrid Control Based Of Dynamic Objects Of Neuro-Fuzzy Inference, Noilakhon Yakubova

Karakalpak Scientific Journal

The Results of interaction of the work is development of a method of control that allows simplifying, automating and unifying the process of design of the hybrid systems which are a basis of modern automation. To achieve a definite purpose, a method of control of a technical object based on the construction of an adaptive system of neuro-fuzzy inference is developed. The objects of the system of neuro-fuzzy inference are the classical and neuro-fuzzy models of control. Information exchange between models is provided by means of the developed hybrid control system. The result of the interaction of the two models …

Application Of A Synergetic Approach To The Problem Of Synthesizing An Intelligent Control System For Chemical Reactors, Komil Usmanov

Karakalpak Scientific Journal

The article deals with the synthesis of effective algorithms for controlling a chemical reactor and developed a intelligent synergistic controller for a class of indefinite nonlinear dynamic systems. A synergetic control scheme is proposed for solving the control problem for nonlinear systems. Non-linear systems with configurations and parameters that change over time require a completely non-linear model and adaptive control scheme for a practical operating environment. The synthesis of control laws is performed by the method of analytical design of aggregated controllers (ADAR).

Development Of The Implementation Of Iot Monitoring System Based On Node-Red Technology, Anvar Kabulov, Inomjon Yarashov, Salamat Mirzataev

Karakalpak Scientific Journal

This article describes how to design and implement a process for storing environmental information in a database using the Internet of Things. The problems that need to be solved with the help of this IoT system are the growing demand for forecasts in the world, the demand of the world market for a new sustainable method of implementing the digitization environment through the Internet of Things. The design was implemented using Arduino, Node-Red and sensors, selected when choosing a component based on the required parameters and sent to the database for monitoring and processing. A study of previous work and …

Theoretical Features Of Foreign Systems Of Preschool Education, Ayjamal Bazarbaeva

Karakalpak Scientific Journal

This article analyzes the features of preschool education systems in foreign countries. The positive experience and features of some systems are highlighted. Comparison of domestic and foreign systems of preschool education is carried out.

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Supporting Information For Chromophoric Dissolved Organic Matter (Cdom) Across An Elevational Gradient From Sea Level To Mountain Lakes In The Pacific Northwest, Kyle Juetten, Angela L. Strecker, Aaron Harrison, Zachary Landram, Warren J. De Bruyn, Catherine D. Clark

Chemistry Faculty and Staff Publications

This dataset is in support of Juetten et al., which has been submitted to the Journal of Geophysical Research Biogeosciences for consideration for publication. Chromophoric dissolved organic matter (CDOM) in lakes across elevation gradients is a complex function of topography, climate, vegetation coverage, land use, and lake properties. To examine sources and processing of CDOM from sea level to mountain lakes (3 to 1574 m), we measured CDOM optical properties, lake characteristics, and water quality parameters in 62 freshwater lakes in the Pacific Northwest, USA. Higher elevation lakes had lower dissolved organic carbon (DOC) and absorbance. These lakes had higher …

Co-Microencapsulation Of Ruellia Tuberosa L. And Cosmos Caudatus K. Extracts For Pharmaceutical Applications, Choirin Annisa, Sasangka Prasetyawan, Anna Safitri

Makara Journal of Science

This study aims to co-microencapsulate the Ruellia tuberosa L. and Cosmos caudatus K. extracts, with chitosan–sodium tripolyphosphate (Na-TPP) as coating material. α-Amylase inhibition and antioxidant assays were conducted to determine the potential of microcapsules used as antidiabetic agents. The microcapsules were manufactured under the influences of pH, Na-TPP concentration, and stirring time. The optimum microencapsulation conditions were selected based on the highest encapsulation efficiency. The optimum microencapsulation conditions were a pH of 4, Na-TPP concentration of 0.15% (w/v), and stirring time of 60 min. The microcapsules exhibited an IC₅₀ (inhibitory concentration) value of 223.64 ± 0.81 µg/mL and an …

Preparation Of Zn/Al-Chitosan Composite For The Selective Adsorption Of Methylene Blue Dye In Water, Risfidian Mohadi, Patimah Mega Syah Bahar Nur Siregar, Neza Rahayu Palapa, Aldes Lesbani

Makara Journal of Science

Layered double hydroxide (LDHs) are widely used adsorbents for methylene blue removal. However, LDHs have a perishable structure that cannot be used repeatedly. Modifying LDHs with chitosan produces a strong material with a large surface area for methylene blue adsorption. Adsorption conditions were optimized by determining the adsorption isotherms and the adsorbent regeneration process. Results showed that the adsorption process was balanced in 90 min with maximum adsorption capacities of 86.207 mg/g, 35.336 mg/g, and 98.039 mg/g for Zn/Al, chitosan, and Zn/Al-chitosan, respectively. The adsorption in this study followed the Freundlich isotherm model. Regeneration analysis of the adsorbent showed that …

Mechanism Of Sila- And Germafluorenes For Biological Applications, Shelby Jarrett

Dissertations

2,7-disubstituted silafluorenes and germafluorenes, originally designed for OLED applications, are a class of fluorescent dyes that have gained recent interest as probes for bioimaging and as biosensors to monitor cellular dynamics and interactions. Desirable biological probes absorb in the visible region, have high extinction coefficients, high quantum yield and excellent photostability. Here, their spectral properties are investigated under aqueous conditions for relevant biological applications. These molecules display intense blue fluorescence in the solid state and in solution, have high extinction coefficients, and exhibit appreciable solubility in aqueous solution. To better understand potential applications, the mechanism of fluorescence was investigated. It …

New Simple And Robust Method For Determination Of Polarity Of Deep Eutectic Solvents (Dess) By Means Of Contact Angle Measurement, Łukasz Cichocki, Dorota Warmińska, Justyna Łuczak, Grzegorz Boczkaj, Andrzej Przyjazny

Natural Sciences Publications

The paper presents a new method for evaluating the polarity and hydrophobicity of deep eutectic solvents (DESs) based on the measurement of the DES contact angle on glass. DESs consisting of benzoic acid derivatives and quaternary ammonium chlorides–tetrabutylammonium chloride (TBAC) and benzyldimethylhexadecylammonium chloride (16-BAC)—in selected molar ratios were chosen for the study. To investigate the DESs polarity, an optical goniometer and an ET(30)" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; font-size: 13.2px; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; color: rgb(34, 34, 34); font-family: Arial, …

Allosteric Mechanism On Dream Dimerization And Impact On Its Interactions With Divalent Metal Zn2+, Maria D. Santiago Estevez

FIU Electronic Theses and Dissertations

DREAM belongs to the NCS family, and it is involved in several physiological processes mediated by Ca²⁺ association, which produces changes in its oligomerization state. The mechanism of how Ca²⁺ binds to DREAM remains unknown. A kinetic study of the binding of Ca²⁺ to DREAM suggested that DREAM dimerization is a two-step process, the first step( τ₁= 8±0.1ms) is associated with the binding of Ca²⁺ to the monomer, while the second step (τ₂ = 3.6 ±0.4 s ) corresponds to a conformation relaxation that leads to the dimerization. Furthermore, by analyzing the fast …

Assessment Of The Toxicity Of Legacy And Next-Generation Perfluoroalkyl Substances (Pfas) In Early-Life Stages Of Freshwater And Marine Fish, Kiflom Gebreab

FIU Electronic Theses and Dissertations

Per- and polyfluoroalkyl substances (PFASs) are a group of synthetic surfactants that have utilized for several decades in a wide range of industrial and manufacturing applications. Owing to their high chemical stability, PFAS are widespread and persistent in the environment, and have been shown to be bioaccumulative in diverse organisms including plants, wildlife, and humans. Exposure to PFASs has been linked to a range of documented toxic and/or adverse effects in relation to human and animal health. The potential environmental health and ecotoxicity of next-generation PFAS remain unclear. In the present study, toxicity, and bioconcentration potential, of several perfluoroether carboxylic …

Asymmetrical Spectral Continuum Between Anti-Stokes And Stokes Scattering Revealed In Low-Frequency Surface-Enhanced Raman Spectroscopy, Shuo Sun, Dhanusha T.N. Rathnayake, Yinsheng Guo

Chemistry Department: Faculty Publications

An asymmetrical spectral continuum is observed in low-frequency surface-enhanced Raman spectroscopy (LF-SERS) in the terahertz (THz) region. This background continuum appears as a flat baseline in the Stokes side and a slope in the anti-Stokes side. Analysis shows this asymmetry originates from the different scaling of anti-Stokes and Stokes scattering with respect to the Bose−Einstein distribution. Such asymmetry is readily visible, under room temperature, in the low-frequency THz spectral range. Accounting for this spectral intensity asymmetry reveals the intrinsic continuum background of electronic origin, differing from local normal modes and collective relaxational motions. We also describe a numerical method, independent …

Exonuclease Digestion Assay For Streamlining Aptamer Characterization, Engineering, And Sensor Development, Juan Canoura

FIU Electronic Theses and Dissertations

Aptamers are DNA or RNA oligonucleotide-based bioreceptors isolated in vitro through the Systematic Evolution of Ligands by Exponential Enrichment. Given the ease with which a selection can be customized, aptamers can be evolved to function in nearly any chemical environment, making them tailormade for their final application. However, the post-SELEX characterization of the 100-1000’s aptamer candidates remains a significant bottleneck as there are no suitable techniques for high-throughput characterization of each candidate’s affinity/specificity. Moreover, the final aptamer must be engineered to possess signal reporting functionality; this is often done via trail-and-error truncation to yield a structure-switching aptamer. This dissertation describes …

Ultrasmall Nanodiamonds: Perspectives And Questions, Shery L.Y. Chang, Philipp Reineck, Anke Krueger, Vadym Mochalin

Chemistry Faculty Research & Creative Works

Nanodiamonds are at the heart of a plethora of emerging applications in areas ranging from nanocomposites and tribology to nanomedicine and quantum sensing. The development of alternative synthesis methods, a better understanding, and the availability of ultrasmall nanodiamonds of less than 3 nm size with a precisely engineered composition, including the particle surface and atomic defects in the diamond crystal lattice, would mark a leap forward for many existing and future applications. Yet today, we are unable to accurately control nanodiamond composition at the atomic scale, nor can we reliably create and isolate particles in this size range. In this …

Development Of Electrochemical Aptamer-Based Sensors For Sensitive And Specific Detection Of Small-Molecule Targets, Yingzhu Liu

FIU Electronic Theses and Dissertations

Electrochemical aptamer-based (E-AB) sensors have been applied for diverse applications such as forensic science, pharmaceutical diagnostics, food safety, environmental monitoring, and personal medical care due to their rapid, accurate, and specific detection of analytes in complex samples. However, limited sensitivity and a lack of portable devices for point-of-care applications have greatly hindered the maturation of E-AB sensors from proof-of-concept designs to commercial systems. This dissertation describes several novel strategies to improve the sensitivities of E-AB sensors and fabricate portable paper-based devices to remedy these problems. We first detail the development of a novel approach to utilize a defined mixture of …

Application Of Numerical Simulation Method In Periodic Pulse Reverse Electroplating Through Hole, Yuan-Hang Zhang, Mao-Zhong An, Pei-Xia Yang, Jin-Qiu Zhang

Journal of Electrochemistry

The upgrade of the fifth generation (5G) communication technology increases the number of communication backplane layers and the aspect ratio of through holes on the board, making it more difficult to use traditional direct current deposition for interconnection. Direct current electrodeposition is more prone to uneven coating in the hole, resulting in poor contact between the coating and components, and open circuit. This has a serious impact on the stability of printed circuit board. The periodic pulse reverse plating method can significantly improve the uniformity of high aspect ratio through-hole plating and improve the production quality of through-hole plating through …

An Investigation On The Interface Corrosion Behaviors Of Cobalt Interconnects In Chemical Mechanical Polishing Slurry, Kai-Xuan Qin, Peng-Fei Chang, Yu-Lin Huang, Ming Li, Tao Hang

Journal of Electrochemistry

Cobalt is widely regarded as the most promising interconnect material for 10 nm node and beyond. The development of a chemical mechanical planarization (CMP) slurry suitable for cobalt interconnect is a critical component for the application of cobalt interconnect. During CMP process of the interconnect layer, the achievement of high-quality surface after planarization is greatly challenged by the metal corrosion in CMP slurry. In this contribution, the corrosion behavior of cobalt in a slurry with potassium persulfate (KPS) as an oxidizer, glycine as a complexing agent, and benzotriazole (BTA) as an inhibitor was investigated. Static erosion rates (SER) of cobalt …

Influences Of Suppressing Additive Malachite Green On Superconformal Cobalt Filling And Nucleation, Xiao-Chuan Ma, Ya-Qiang Li, Pei-Xia Yang, Jin-Qiu Zhang, Mao-Zhong An

Journal of Electrochemistry

As the semiconductor integrated circuits evolve into 7 nm technology and beyond, the resistance of the Cu filling at back-end-of-line interconnects no longer linearly scales with dimension. The metal Co with lower mean free path can be used to replace Cu for reducing the line resistance caused by the scattering on the outer surface and grain boundary in the smaller and smaller size. In this study, CoSO₄ was used as the main salt, boric acid as a buffer and malachite green (MG) as an inhibitor for further research. According to the electrochemical cyclic voltammetric (CV) curves by using a …

Study On Low Voltage Electrodeposition Of Diamond-Like Carbon Film, Li Wang, Min-Xian Wu, Jun Li, Yan-Li Chen, Wen-Chang Wang, Zhi-Dong Chen

Journal of Electrochemistry

Diamond-like carbon (DLC) films are receiving a lot of attention from the scientific community, thanks to the promise of DLC films for applications in microelectronics and optoelectronics. Usually, electrodeposition is the preferred common technique because of low cost, large deposition area and simplicity of the setup. However, when carbon films are electrodeposited on a stainless steel, high cell voltages (≥1000 V) are required owing to the low electric conductivity of the organic solvents. This work has developed a new electrolyte system that could achieve carbon deposition on a stainless steel under a low applied cell voltage. The DLC films were …

Study On Weak Alkaline Cyanide-Free Silver Plating Process For Etching Lead Frame, Jian-Wei Zhao, Hai-Feng Zhu, Xiao-Hui Yu, Gui-Yun Yuan, Zhi Sun

Journal of Electrochemistry

As a new development direction of integrated circuit chip carrier, etched lead frame has been gradually applied in microelectronics industry in recent years. Since the preparation of the etched lead frame requires the use of multiple layers of non-alkali-resistant photoresist films with specific patterns, and the traditional cyanide silver plating is unable to meet this requirement, making that the development of weakly alkaline cyanide free silver plating process has great significance. In this paper, a weak alkaline silver plating process based on 5,5-dimethylhydantoin (DMH) cyanide-free silver plating system was studied. The electrodeposition behavior of the system and the nucleation mechanism …