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2022

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Articles 271 - 300 of 1634

Full-Text Articles in Chemistry

Combining Freestanding Ferroelectric Perovskite Oxides With Two-Dimensional Semiconductors For High Performance Transistors, Sergio Puebla, Thomas Pucher, Victor Rouco, Gabriel Sanchez-Santolino, Yong Xie, Victor Zamora, Fabian A. Cuellar, Federico J. Mompean, Carlos Leon, Carlos O. Island, Mar Garcia-Hernandez, Jacobo Santamaria, Carmen Munuera, Andres Castellanos-Gomez Sep 2022

Combining Freestanding Ferroelectric Perovskite Oxides With Two-Dimensional Semiconductors For High Performance Transistors, Sergio Puebla, Thomas Pucher, Victor Rouco, Gabriel Sanchez-Santolino, Yong Xie, Victor Zamora, Fabian A. Cuellar, Federico J. Mompean, Carlos Leon, Carlos O. Island, Mar Garcia-Hernandez, Jacobo Santamaria, Carmen Munuera, Andres Castellanos-Gomez

Physics & Astronomy Faculty Research

We demonstrate the fabrication of field-effect transistors based on single-layer MoS2 and a thin layer of BaTiO3 (BTO) dielectric, isolated from its parent epitaxial template substrate. Thin BTO provides an ultrahigh-κ gate dielectric effectively screening Coulomb scattering centers. These devices show mobilities substantially larger than those obtained with standard SiO2 dielectrics and comparable with values obtained with hexagonal boron nitride, a dielectric employed for fabrication of high-performance two-dimensional (2D) based devices. Moreover, the ferroelectric character of BTO induces a robust hysteresis of the current vs gate voltage characteristics, attributed to its polarization switching. This hysteresis is strongly suppressed when the …


A Blind Benchmark Of Analysis Tools To Infer Kinetic Rate Constants From Single-Molecule Fret Trajectories, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara Sep 2022

A Blind Benchmark Of Analysis Tools To Infer Kinetic Rate Constants From Single-Molecule Fret Trajectories, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara

Faculty Scholarship

Single-molecule FRET (smFRET) is a versatile technique to study the dynamics and function of biomolecules since it makes nanoscale movements detectable as fluorescence signals. The powerful ability to infer quantitative kinetic information from smFRET data is, however, complicated by experimental limitations. Diverse analysis tools have been developed to overcome these hurdles but a systematic comparison is lacking. Here, we report the results of a blind benchmark study assessing eleven analysis tools used to infer kinetic rate constants from smFRET trajectories. We test them against simulated and experimental data containing the most prominent difficulties encountered in analyzing smFRET experiments: different noise …


Ice-Nucleating Agents In Sea Spray Aerosol Identified And Quantified With A Holistic Multimodal Freezing Model, Peter A. Alpert, Wendy P. Kilthau, Rachel E. O'Brien, Ryan C. Moffet, Mary K. Gilles, Bingbing Wang, Alexander Laskin, Josephine Y. Aller, Daniel A. Knopf Sep 2022

Ice-Nucleating Agents In Sea Spray Aerosol Identified And Quantified With A Holistic Multimodal Freezing Model, Peter A. Alpert, Wendy P. Kilthau, Rachel E. O'Brien, Ryan C. Moffet, Mary K. Gilles, Bingbing Wang, Alexander Laskin, Josephine Y. Aller, Daniel A. Knopf

Pacific Faculty Work

Sea spray aerosol (SSA) is a widely recognized important source of ice-nucleating particles (INPs) in the atmosphere. However, composition-specific identification, nucleation processes, and ice nucleation rates of SSA-INPs have not been well constrained. Microspectroscopic characterization of ambient and laboratory-generated SSA confirms that water-borne exudates from planktonic microorganisms composed of a mixture of proteinaceous and polysaccharidic compounds act as ice-nucleating agents (INAs). These data and data from previously published mesocosm and wave channel studies are subsequently used to further develop the stochastic freezing model (SFM) producing ice nucleation rate coefficients for SSA-INPs. The SFM simultaneously predicts immersion freezing and deposition and …


Markovnikov Alcohols Via Epoxide Hydroboration By Molecular Alkali Metal Catalysts, Guoqi Zhang, Haisu Zeng, Shengping Zheng, Michelle C. Neary, Los Alamos National Laboratory Sep 2022

Markovnikov Alcohols Via Epoxide Hydroboration By Molecular Alkali Metal Catalysts, Guoqi Zhang, Haisu Zeng, Shengping Zheng, Michelle C. Neary, Los Alamos National Laboratory

Publications and Research

Summary

Synthesis of branched “Markovnikov” alcohols is crucial to various chemical industries. The catalytic reduction of substituted epoxides under mild conditions is a highly attractive method for preparing such alcohols. Classical methods based on heterogeneous or homogeneous transition metal-catalyzed hydrogenation, hydroboration, or hydrosilylation usually suffer from poor selectivity, reverse regioselectivity, limited functional group compatibility, high cost, and/or low availability of the catalysts. Here we report the discovery of highly regioselective hydroboration of nonsymmetrical epoxides catalyzed by ligated archetypal reductants in organic chemistry ‒ alkali metal triethylborohydrides. The chemoselectivity and turnover efficiencies of the present catalytic approach are excellent. Thus, terminal …


Chemical Investigation And Drug Discovery Potential Of Terpenoid Secondary Metabolites From Three Deep-Sea Irish Soft Corals, Joshua Thomas Welsch Sep 2022

Chemical Investigation And Drug Discovery Potential Of Terpenoid Secondary Metabolites From Three Deep-Sea Irish Soft Corals, Joshua Thomas Welsch

USF Tampa Graduate Theses and Dissertations

Secondary metabolites produced primarily by terrestrial plants and animals have provided the basis for treatments and cures of human diseases as far back as historians have been able to probe. However, recent technological advances including the self-contained underwater breathing apparatus, and even further remotely operated vehicles, have allowed researchers a unique opportunity for targeted collection of marine organisms at depths previously thought to possess conditions unsustainable for life as was understood. This has afforded a glimpse into the potential for not only life, but the potential for new biochemical adaptations developed over billions of years that have been evolutionarily developed …


In Silico Evaluation Of The Antimalarial Potential Of The Phytoconstituents Of The Azadirachta Indica Plant, Areh E.T., Atolani O., Kambizi L Sep 2022

In Silico Evaluation Of The Antimalarial Potential Of The Phytoconstituents Of The Azadirachta Indica Plant, Areh E.T., Atolani O., Kambizi L

Al-Bahir

Background and Objectives: Malaria, a parasitic protozoan disease caused primarily by Plasmodium falciparum, has killed millions of people in Africa, particularly those with meager or no access to orthodox medical facilities and therapies. Extracts from the Azadirachta indica (neem) plant is believed to possess antimalaria properties among the locals that rely on herbs. Numerous in - vivo studies have suggested the antimalarial properties of neem extract and phytochemicals. This study employs an in - silico method through molecular docking techniques to provide insight while adding credence to the antimalarial potential of phytochemicals of neem plants as claimed …


Ambient-Pressure Ozone Treatment Enables Tuning Of Oxygen Vacancy Concentration In The La1−XSrXFeo3−Δ (0 ≤ X ≤ 1) Perovskite Oxides, Geletu Qing, David Thompson, Mourad Benamara, Clemens Heske, Lauren Greenlee, Jingyi Chen Sep 2022

Ambient-Pressure Ozone Treatment Enables Tuning Of Oxygen Vacancy Concentration In The La1−XSrXFeo3−Δ (0 ≤ X ≤ 1) Perovskite Oxides, Geletu Qing, David Thompson, Mourad Benamara, Clemens Heske, Lauren Greenlee, Jingyi Chen

Chemistry and Biochemistry Faculty Research

Oxygen vacancies in metal oxides can determine their properties. However, it is difficult to reduce the oxygen vacancy concentration in metal oxides without annealing them under high pressure. In this work, we develop a facile approach to control oxygen vacancy content via an ozone treatment under ambient pressure during cooling. This approach is demonstrated for the synthesis of La1−xSrxFeO3−δ (0 ≤ x ≤ 1, 0 ≤ δ ≤ 0.5x) perovskite oxides – an important class of energy-related materials due to their wide range of non-stoichiometry, mixed ionic and electronic conductivity, and …


Design Of Pd–Zn Bimetal Mof Nanosheets And Mof-Derived Pd3.9zn6.1/Cns Catalyst For Selective Hydrogenation Of Acetylene Under Simulated Front-End Conditions, Xinxiang Cao, Ruijian Tong, Siye Tang, Ben W.-L. Jang Sep 2022

Design Of Pd–Zn Bimetal Mof Nanosheets And Mof-Derived Pd3.9zn6.1/Cns Catalyst For Selective Hydrogenation Of Acetylene Under Simulated Front-End Conditions, Xinxiang Cao, Ruijian Tong, Siye Tang, Ben W.-L. Jang

Faculty Publications

Novel zinc–palladium–porphyrin bimetal metal–organic framework (MOF) nanosheets were directly synthesized by coordination chelation between Zn(II) and Pd(II) tetra(4-carboxyphenyl) porphin (TCPP(Pd)) using a solvothermal method. Furthermore, a serial of carbon nanosheets supported Pd–Zn intermetallics (Pd–Zn-ins/CNS) with different Pd: Zn atomic ratios were obtained by one-step carbonization under different temperature using the prepared Zn-TCPP(Pd) MOF nanosheets as precursor. In the carbonization process, Pd–Zn-ins went through the transformation from PdZn (650 C) to Pd3.9Zn6.1 (~950 C) then to Pd3.9Zn6.1/Pd (1000 C) with the temperature increasing. The synthesized Pd–Zn-ins/CNS were further employed as catalysts for selective hydrogenation of acetylene. Pd3.9Zn6.1 showed the best catalytic …


Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha Sep 2022

Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha

Chemistry Faculty Publications

Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited. In this work, we have reported direct ink 3D printing of porous carbon; the ink consisted of commercial activated carbon, a gel of poly(4-vinylphenol) and Pluronic F127 as plasticizer, and bentonite as the binder. The 3D printing was performed …


Multimodal Cotranslational Interactions Direct Assembly Of The Human Multi-Trna Synthetase Complex, Krishnendu Khan, Briana Long, Valentin Gogonea, Gauravi M. Deshpande, Kommireddy Vasu, Paul L. Fox Sep 2022

Multimodal Cotranslational Interactions Direct Assembly Of The Human Multi-Trna Synthetase Complex, Krishnendu Khan, Briana Long, Valentin Gogonea, Gauravi M. Deshpande, Kommireddy Vasu, Paul L. Fox

Chemistry Faculty Publications

Amino acid ligation to cognate transfer RNAs (tRNAs) is catalyzed by aminoacyl-tRNA synthetases (aaRSs)-essential interpreters of the genetic code during translation. Mammalian cells harbor 20 cytoplasmic aaRSs, out of which 9 (in 8 proteins), with 3 non-aaRS proteins, AIMPs 1 to 3, form the similar to 1.25-MDa multi-tRNA synthetase complex (MSC). The function of MSC remains uncertain, as does its mechanism of assembly. Constituents of multiprotein complexes encounter obstacles during assembly, including inappropriate interactions, topological constraints, premature degradation of unassembled subunits, and suboptimal stoichiometry. To facilitate orderly and efficient complex formation, some complexes are assembled cotranslationally by a mechanism in …


Tetrahydrocurcumin Improves Lipopolysaccharide-Induced Myocardial Dysfunction By Inhibiting Oxidative Stress And Inflammation Via Jnk/Erk Signaling Pathway Regulation, Hanzhao Zhu, Liyun Zhang, Hao Jia, Lu Xu, Yu Cao, Mengen Zhai, Kaifeng Li, Lin Xia, Liqing Jiang, Xiang Li, Yenong Zhou, Jincheng Liu, Shiqiang Yu, Weixun Duan Sep 2022

Tetrahydrocurcumin Improves Lipopolysaccharide-Induced Myocardial Dysfunction By Inhibiting Oxidative Stress And Inflammation Via Jnk/Erk Signaling Pathway Regulation, Hanzhao Zhu, Liyun Zhang, Hao Jia, Lu Xu, Yu Cao, Mengen Zhai, Kaifeng Li, Lin Xia, Liqing Jiang, Xiang Li, Yenong Zhou, Jincheng Liu, Shiqiang Yu, Weixun Duan

Chemistry Undergraduate Publications

Background

Acute myocardial dysfunction in patients with sepsis is attributed to oxidative stress, inflammation, and cardiomyocyte loss; however, specific drugs for its prevention are still lacking. Tetrahydrocurcumin (THC) has been proven to contribute to the prevention of various cardiovascular diseases by decreasing oxidative stress and inflammation. This study was performed to investigate the functions and mechanism of action of THC in septic cardiomyopathy.

Methods

After the oral administration of THC (120 mg/kg) for 5 consecutive days, a mouse model of sepsis was established via intraperitoneal lipopolysaccharide (LPS, 10 mg/kg) injection. Following this, cardiac function was assessed, pathological section staining was …


Material Analysis And Conservation Treatment Of Louise Nevelson’S Sculpture Dawn’S Image, Night, Kaela Nurmi Sep 2022

Material Analysis And Conservation Treatment Of Louise Nevelson’S Sculpture Dawn’S Image, Night, Kaela Nurmi

Art Conservation Master's Projects

Louise Nevelson’s large-scale, matte black assemblage sculpture Dawn’s Image, Night, 1969, is owned by and currently on display at SUNY Buffalo State College. The paint layers exhibited significant amounts of dust, some damages, vandalism, and unsightly fingerprints. Extensive scientific analysis and archival research were utilized to design an appropriate treatment and long-term preservation plan. Methods of analysis include: Fourier transform infrared spectroscopy, pyrolysis-gas chromatography-mass spectrometry, microchemical testing, and xray fluorescence spectroscopy. The project also addresses the ethical considerations surrounding the prior removal of original components for safety considerations, repainting as a possible treatment, and the overall obstacles of treating a …


Chemical Composition Of Kombucha, Peyton Bishop, Eric R. Pitts, Drew Budner, Katherine A. Thompson-Witrick Sep 2022

Chemical Composition Of Kombucha, Peyton Bishop, Eric R. Pitts, Drew Budner, Katherine A. Thompson-Witrick

Chemistry

Kombucha is a fermented sweetened tea with a mixed fermenting culture of yeast and acetic acid bacteria. While the history of kombucha is not completely clear, it is now available around the world and has shown an increase in availability and demand in the United States market. The proponents of kombucha consumption tout the varied health benefits it can provide. The final kombucha flavor and composition is a function of both the initial tea used and the fermentation process. While the ascribed benefits are varied and numerous, the number of direct studies has been limited. This review focuses on the …


Advanced Glycation End Products In Health And Disease, V. Prakash Reddy, Puspa Aryal, Emmanuel K. Darkwah Sep 2022

Advanced Glycation End Products In Health And Disease, V. Prakash Reddy, Puspa Aryal, Emmanuel K. Darkwah

Chemistry Faculty Research & Creative Works

Advanced glycation end products (AGEs), formed through the nonenzymatic reaction of reducing sugars with the side-chain amino groups of lysine or arginine of proteins, followed by further glycoxidation reactions under oxidative stress conditions, are involved in the onset and exacerbation of a variety of diseases, including diabetes, atherosclerosis, and Alzheimer's disease (AD) as well as in the secondary stages of traumatic brain injury (TBI). AGEs, in the form of intra- and interprotein crosslinks, deactivate various enzymes, exacerbating disease progression. The interactions of AGEs with the receptors for the AGEs (RAGE) also result in further downstream inflammatory cascade events. The overexpression …


Polyphenols And Small Phenolic Acids As Cellular Metabolic Regulators, Mark Obrenovich, Yi Li, Moncef Tayahi, V. Prakash Reddy Sep 2022

Polyphenols And Small Phenolic Acids As Cellular Metabolic Regulators, Mark Obrenovich, Yi Li, Moncef Tayahi, V. Prakash Reddy

Chemistry Faculty Research & Creative Works

Polyphenols and representative small phenolic acids and molecules derived from larger constituents are dietary antioxidants from fruits, vegetables and largely other plant-based sources that have ability to scavenge free radicals. What is often neglected in polyphenol metabolism is bioavailability and the role of the gut microbiota (GMB), which has an essential role in health and disease and participates in co-metabolism with the host. The composition of the gut microbiota is in constant flux and is modified by multiple intrinsic and extrinsic factors, including antibiotics. Dietary or other factors are key modulators of the host gut milieu. In this review, we …


Crystal Structure, Electronic Structure, And Optical Properties Of The Novel Li4cdge2s7, A Wide-Bandgap Quaternary Sulfide With A Polar Structure Derived From Lonsdaleite, Andrew J. Craig, Seung Han Shin, Jeong Bin Cho, Srikanth Balijapelly, Jordan C. Kelly, Stanislav S. Stoyko, Amitava Choudhury, Joon I. Jang, Jennifer A. Aitken, A. Sarjeant Sep 2022

Crystal Structure, Electronic Structure, And Optical Properties Of The Novel Li4cdge2s7, A Wide-Bandgap Quaternary Sulfide With A Polar Structure Derived From Lonsdaleite, Andrew J. Craig, Seung Han Shin, Jeong Bin Cho, Srikanth Balijapelly, Jordan C. Kelly, Stanislav S. Stoyko, Amitava Choudhury, Joon I. Jang, Jennifer A. Aitken, A. Sarjeant

Chemistry Faculty Research & Creative Works

The novel quaternary thiogermanate Li4CdGe2S7 (tetralithium cadmium digermanium heptasulfide) was discovered from a solid-state reaction at 750 °C. Single-crystal X-ray diffraction data were collected and used to solve and refine the structure. Li4CdGe2S7 is a member of the small, but growing, class of I4-II-IV2-VI7 diamond-like materials. The compound adopts the Cu5Si2S7 structure type, which is a derivative of lonsdaleite. Crystallizing in the polar space group Cc, Li4CdGe2S7 contains 14 crystallographically unique ions, all residing on …


Catalyzed And Uncatalyzed N1 Modifications Of Inosine And 2'-Deoxyinosine And N-Directed Remote Aroylation Of C6-Aryl Purine Nucleosides, Casina Malinchak Sep 2022

Catalyzed And Uncatalyzed N1 Modifications Of Inosine And 2'-Deoxyinosine And N-Directed Remote Aroylation Of C6-Aryl Purine Nucleosides, Casina Malinchak

Dissertations, Theses, and Capstone Projects

Nucleosides, and their analogs, are important biological molecules that are integral to cell signaling, metabolism, and DNA and RNA synthesis. Because of their presence in all living systems, they are ideal candidates for drug development. Although extensive literature exists on the alkylation and alkenylation at N1 of inosine and 2’-deoxyinosine, few reports have been published on arylation at this position. Using diaryliodonium salts, a copper-catalyzed method has been developed for the efficient N1-arylation of silyl group-protected inosine and 2’-deoxyinosine. Diaryliodonium salts are easily synthesized and allow for the use of mild conditions to promote transfer of aryl groups to the …


Sensitized Photooxidation Of Prenylated Compounds: Mechanisms Of Downstream Dark Effects And Phototoxicity Priming, Shakeela Jabeen Sep 2022

Sensitized Photooxidation Of Prenylated Compounds: Mechanisms Of Downstream Dark Effects And Phototoxicity Priming, Shakeela Jabeen

Dissertations, Theses, and Capstone Projects

This thesis consists of four chapters as detailed below.

Chapter 1 discusses a singlet oxygen priming mechanism. Airborne singlet oxygen derived from photosensitization of triplet dioxygen is shown to react with an alkene surfactant (8-methylnon-7-ene-1 sulfonate) leading to ‘ene’ hydroperoxides that in the dark inactivate planktonic E. coli. The ‘ene’ hydroperoxide photoproducts are not toxic on their own, but they become toxic after the bacteria are pretreated with singlet oxygen. The total quenching rate constant (kT) of singlet oxygen of the alkene surfactant was measured to be 1.1 × 106 M1 s− …


Visible Light Photocatalysis Of Organic Reactions In H2o, Sankarsan Biswas Sep 2022

Visible Light Photocatalysis Of Organic Reactions In H2o, Sankarsan Biswas

Dissertations, Theses, and Capstone Projects

Visible-light photocatalysis in H2O provides an attractive, green alternative to typical organic synthesis, which often involves toxic solvents, metal catalysts, and large energy demands. Hence, there is a growing need for an efficient photocatalytic methods that use either aqueous media as a solvent or can proceed solvent-free. However, commercially available photocatalysts do not work well for aqueous photocatalysis. Supramolecular systems in particular have been explored recently to address these issues associated with aqueous photocatalysis. Chapter 1 will review recent advances in aqueous supramolecular photocatalysis with examples of different supramolecular systems and how they have addressed some of the …


Application Of Peo-Ppo-Peo Triblock Copolymers In Synthesis Of Silica And Organosilica Nanomaterials, Shu Zhang Sep 2022

Application Of Peo-Ppo-Peo Triblock Copolymers In Synthesis Of Silica And Organosilica Nanomaterials, Shu Zhang

Dissertations, Theses, and Capstone Projects

In this dissertation, the research work focused on the application of Pluronic triblock copolymers, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), in the synthesis of mesoporous material, such as double-helical silica nanotube structures as well as bridged organosilica nanotubes by using swollen micelles of Pluronic surfactants and their mixtures. Chapter 1 introduced the background and several important mesoporous structures, and the relevant topics in this dissertation, such as, silica nanotubes, helical silica nanotubes, silica vesicles and organosilica nanotubes. Chapter 2, continued research works from earlier published paper (ACS Nano 2021, 15, 1016-1029), discussed static treatment and stirring effect on the formation of …


Conformation Of The U12-U6atac Snrna Complex Of The Minor Spliceosome And Binding By Ntc-Related Protein Rbm22, Joanna Ciavarella Sep 2022

Conformation Of The U12-U6atac Snrna Complex Of The Minor Spliceosome And Binding By Ntc-Related Protein Rbm22, Joanna Ciavarella

Dissertations, Theses, and Capstone Projects

Splicing of precursor messenger (pre-m)RNA is a critical process in eukaryotes in which the non-coding regions, called introns, are removed and coding regions, or exons, are ligated to form a mature mRNA. This process is catalyzed by the spliceosome, a multi-mega Dalton ribonucleoprotein complex assembled from five small nuclear ribonucleoproteins (snRNP) in the form of small nuclear (sn)RNA-protein complexes (U1, U2, U4, U5 and U6) and >100 proteins. snRNA components catalyze the two transesterification reactions while proteins perform critical roles in assembly and rearrangement. U2 and U6 snRNAs are the only snRNAs directly implicated in catalyzing the splicing of pre-mRNA. …


Engineering Rare-Earth Based Color Centers In Wide Bandgap Semiconductors For Quantum And Nanoscale Applications, Gabriel I. López-Morales Sep 2022

Engineering Rare-Earth Based Color Centers In Wide Bandgap Semiconductors For Quantum And Nanoscale Applications, Gabriel I. López-Morales

Dissertations, Theses, and Capstone Projects

For many years, atomic point-defects have been readily used to tune the bulk properties of solid-state crystalline materials, for instance, through the inclusion of elemental impurities (doping) during growth, or post-processing treatments such as ion bombardment or high-energy irradiation. Such atomic point-defects introduce local ‘incompatible’ chemical interactions with the periodic atomic arrangement that makes up the crystal, resulting for example in localized electronic states due to dangling bonds or excess of electrons. When present in sufficient concentrations, the defects interact collectively to alter the overall bulk properties of the host material. In the low concentration limit, however, point-defects can serve …


The Interaction Of Different Primary Producers And Physical And Chemical Dynamics Of An Urban Shallow Lake, Majid Sahin Sep 2022

The Interaction Of Different Primary Producers And Physical And Chemical Dynamics Of An Urban Shallow Lake, Majid Sahin

Dissertations, Theses, and Capstone Projects

An artificial urban shallow lake, Prospect Park Lake (PPL), is situated on a terminal moraine in Brooklyn New York, and supplied with municipal water treated with ortho-phosphates. The constant input of the phosphate nutrient is the primary source of eutrophication in the lake. The numerous pools along the water course houses various aquatic phototrophs, which influence the water quality and the state of the system, driving conditions into favoring the survival of their species. In the first half of the dissertation, the focus of the project is on analyzing how the different primary producers in different regions of PPL affect …


Growth, Optimization, And Characterization Of Topological Insulator Nanostructures By Molecular Beam Epitaxy, Ido Levy Sep 2022

Growth, Optimization, And Characterization Of Topological Insulator Nanostructures By Molecular Beam Epitaxy, Ido Levy

Dissertations, Theses, and Capstone Projects

Topological insulators (TIs) have been the subject of much research since their discovery in 2009. The unique band structure of the TIs makes them attractive in research of exotic physical phenomena, such as the realization of the quantum anomalous Hall effect, as well as novel applications, including quantum computing, spintronics, and more. From a crystal growth perspective, their van-der-Waals structure also provides new opportunities, for example, by enabling the growth on a large selection of substrates. This thesis presents the growth of three-dimensional TI layers, heterostructures and magnetic TIs by molecular beam epitaxy (MBE). First, we show the improvement of …


Excitation-Dependent Photoluminescence Of Bazro3:Eu3+ Crystals, Santosh K. Gupta, Hisham Abdou, Carlo U. Segre, Yuanbing Mao Aug 2022

Excitation-Dependent Photoluminescence Of Bazro3:Eu3+ Crystals, Santosh K. Gupta, Hisham Abdou, Carlo U. Segre, Yuanbing Mao

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The elucidation of local structure, excitation-dependent spectroscopy, and defect engineering in lanthanide ion-doped phosphors was a focal point of research. In this work, we have studied Eu3+-doped BaZrO3 (BZOE) submicron crystals that were synthesized by a molten salt method. The BZOE crystals show orange–red emission tunability under the host and dopant excitations at 279 nm and 395 nm, respectively, and the difference is determined in terms of the asymmetry ratio, Stark splitting, and intensity of the uncommon 5D07F0 transition. These distinct spectral features remain unaltered under different excitations for the BZOE …


Ai Protein Structure Prediction-Based Modeling And Mutagenesis Of A Protostome Receptor And Peptide Ligands Reveal Key Residues For Their Interaction, Shi-Qi Guo, Ya-Dong Li, Ping Chen, Guo Zhang, Hui-Ying Wang, Hui-Min Jiang, Wei-Jia Liu, Ju-Ping Xu, Xue-Ying Ding, Ping Fu, Ke Yu, Hai-Bo Zhou, James W. Checco, Jian Jing Aug 2022

Ai Protein Structure Prediction-Based Modeling And Mutagenesis Of A Protostome Receptor And Peptide Ligands Reveal Key Residues For Their Interaction, Shi-Qi Guo, Ya-Dong Li, Ping Chen, Guo Zhang, Hui-Ying Wang, Hui-Min Jiang, Wei-Jia Liu, Ju-Ping Xu, Xue-Ying Ding, Ping Fu, Ke Yu, Hai-Bo Zhou, James W. Checco, Jian Jing

Department of Chemistry: Faculty Publications

The protostome leucokinin (LK) signaling system, including LK peptides and their G protein-coupled receptors, has been characterized in several species. Despite the progress, molecular mechanisms governing LK peptide–receptor interactions remain to be elucidated. Previously, we identified a precursor protein for Aplysia leucokinin-like peptides (ALKs) that contains the greatest number of amidated peptides among LK precursors in all species identified so far. Here, we identified the first ALK receptor from Aplysia, ALKR. We used cell-based IP1 activation assays to demonstrate that two ALK peptides with the most copies, ALK1 and ALK2, activated ALKR with high potencies. Other endogenous ALK-derived peptides …


Quantitative Lithium Composite As 3d Lithium Foam Anode For Lithium Metal Battery, Hu-Dong Li, Wei-Shang Jia, Xin-Xiu Yan, Yao-Yue Yang Aug 2022

Quantitative Lithium Composite As 3d Lithium Foam Anode For Lithium Metal Battery, Hu-Dong Li, Wei-Shang Jia, Xin-Xiu Yan, Yao-Yue Yang

Journal of Electrochemistry

Lithium (Li) metal as an anode material for batteries has extremely high specific capacity and extremely low redox potential, which can significantly improve the energy density of the battery. However, the main problems faced by the use of Li metal anodes are Li dendrite growth, interfacial side reaction and volumetric change of electrode. Herein, a strategy to prepare the three-dimensional (3D) Li foam by combining 3D scaffold with quantitative Li was proposed to suppress Li dendrites growth and alleviate electrode volumetric change. The 3D Li foam facilitated the efficient utilization of Li metal by suppressing the Li dendrite growth, mitigating …


Optimized Electrochemical Performance Of Si@C Prepared By Hydrothermal Reaction And Glucose Carbon Source, Si Chen, Song-Sheng Zheng, Lei-Ming Zheng, Ye-Han Zhang, Zhao-Lin Wang Aug 2022

Optimized Electrochemical Performance Of Si@C Prepared By Hydrothermal Reaction And Glucose Carbon Source, Si Chen, Song-Sheng Zheng, Lei-Ming Zheng, Ye-Han Zhang, Zhao-Lin Wang

Journal of Electrochemistry

Silicon (Si) has been considered as the potential material for the next-generation lithium-ion batteries (LIBs) for its high capacity (4200 mAh·g-1, Li22Si5) and suitable working voltage (about 0.25 V vs. Li/Li+). However, the cycling stability and electrochemical performance of Si anode become significant challenges because of low intrinsic conductivity and huge volume variation (about 400%) during cycling processes. In addition, the repeated formation and destruction of surface solid electrolyte interphase (SEI) film will continuously consume the electrolyte and cause damage to LIBs. Carbon (C) materials, such as graphite, carbon spheres and tubes, …


Facile One-Step Solid-State Synthesis Of Ni-Rich Layered Oxide Cathodes For Lithium-Ion Batteries, Jing-Yue Wang, Rui Wang, Shi-Qi Wang, Li-Fan Wang, Chun Zhan Aug 2022

Facile One-Step Solid-State Synthesis Of Ni-Rich Layered Oxide Cathodes For Lithium-Ion Batteries, Jing-Yue Wang, Rui Wang, Shi-Qi Wang, Li-Fan Wang, Chun Zhan

Journal of Electrochemistry

Nickel-rich layered oxide is one of the dominate cathode materials in the lithium ion batteries, due to its high specific energy density meeting the range requirement of the electric vehicles. Typically, the commercial Ni-rich layered oxides are synthesized from co-precipitated precursors, while precision control is required in the co-precipitation process to ensure the atomic level mixing of the cations such as Ni, Co and Mn, et.al. In this work, a one-step solid-state method was successfully applied to synthesize the Ni-rich layered oxide materials with ultra-high Ni content. By choosing the nickel hydroxides as the precursor with layered structure similar to …


A Novel Electrochemical Sensor Based On Au/Rgo/Feooh For One-Step Detection Of Nitrite, Da-Juan Luo, Bing-Qian Liu, Meng-Yan Qin, Rong Gao, Li-Xia Su, Yong-Huan Su Aug 2022

A Novel Electrochemical Sensor Based On Au/Rgo/Feooh For One-Step Detection Of Nitrite, Da-Juan Luo, Bing-Qian Liu, Meng-Yan Qin, Rong Gao, Li-Xia Su, Yong-Huan Su

Journal of Electrochemistry

Nitrite, a widespread raw material, is harmful to human health for long-term consumption. At present, the detection methods of nitrite mainly include chemical analysis, fluorescence, ultraviolet spectrophotometry and chromatography. These methods have ideal sensitivity and selectivity, but also have some characteristics: cumbersome operation, expensive equipment and professional personnel. Therefore, the development of a simple and sensitive nitrite assay is of great significance. In this paper, the Au/rGO/FeOOH composite materials, which revealed good synergistic catalytic performance among the three elements in the composite, were prepared by simple hydrothermal method and reduction method for the first time with large specific surface area …