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Articles 5941 - 5970 of 15571
Full-Text Articles in Entire DC Network
Inhibition Of Hsv-1 Binding By Egcg-Stearate, Valerie Paschalis
Inhibition Of Hsv-1 Binding By Egcg-Stearate, Valerie Paschalis
Theses, Dissertations and Culminating Projects
Herpes simplex virus type 1 (HSV-1) is the causative agent of oral herpes, and is able to establish lifelong latent infection along with painful, recurring symptoms. Epigallocatechin-3- gallate (EGCG) is the most abundant polyphenol derived from green tea (Camellia sinensis), whose anti-inflammatory, antioxidant, anti-cancer, and antiviral properties have been widely studied. Although EGCG is not chemically stable and has poor hydrophobicity, lipophilic derivatives of EGCG have shown increased stability as well as increased antiviral efficacy against HSV. Previous studies have demonstrated that EGCG stearate (EGCG-S), a derivative of EGCG esterified at the 4’ position with stearic acid, is able to …
Development Of Laser Ablation Direct Analysis In Real Time Imaging-Mass Spectrometry (Ladi-Ms)-Applications To Questions Of Relevance To Forensic Science And Plant Biochemistry, Kristen Leigh Fowble
Development Of Laser Ablation Direct Analysis In Real Time Imaging-Mass Spectrometry (Ladi-Ms)-Applications To Questions Of Relevance To Forensic Science And Plant Biochemistry, Kristen Leigh Fowble
Legacy Theses & Dissertations (2009 - 2024)
Methods for the accomplishment of small molecule imaging by mass spectrometry are challenged by the need for sample pre-treatment steps such as cryo-sectioning, dehydration, chemical fixation, or application of a matrix or solvent, that must be performed to obtain interpretable spatial distribution data. Furthermore, these steps along with requirements of the mass analyzer such as high vacuum, can severely limit the range of sample types that can be analyzed by this powerful method. Here, we report the development of a laser ablation-direct analysis in real time imaging-mass spectrometry (LADI-MS) approach which couples a 213 nm Nd:YAG solid state UV laser …
Novel Mass Spectrometric Approaches For Deciphering The Epitranscriptomic Code, William D. Mcintyre
Novel Mass Spectrometric Approaches For Deciphering The Epitranscriptomic Code, William D. Mcintyre
Legacy Theses & Dissertations (2009 - 2024)
According to the results of the Human Genome Project, less than 5% of our genome consists of sequences that code for actual proteins. At the same time, however, ~90% of these non-coding sequences are transcribed into a myriad of classes of ribonucleic acids collectively known as ncRNAs, which have been recognized as essential regulatory factors. It has been recently shown that the activity of ncRNAs can be in turn modulated by post-transcriptional modifications (PTMs), covalent marks that can be established/removed by tightly regulated enzymatic pathways. Now, the race is on to understand the new set of controls of cellular functions …
Modeling Chaperone-Substrate Interactions Of Alpha Crystallin From The Ocular Lens, Lisa Marie S. Ramirez
Modeling Chaperone-Substrate Interactions Of Alpha Crystallin From The Ocular Lens, Lisa Marie S. Ramirez
Legacy Theses & Dissertations (2009 - 2024)
The α-crystallins (αA- and αB-crystallin isoforms) from the ocular lens are small heat shock proteins and molecular chaperones, widely believed to play a significant role in protecting the lens from cataract. Mutations and modifications on human αA- and αB-crystallin (HAA and HAB, respectively) are linked to a variety of diseases, including cataract formation, neuropathological protein folding disorders, and many others. It is believed that HAA and HAB prevent the aggregation of other lens proteins. However, the structural and thermodynamic details of the chaperone-substrate (aka “client”) interaction are sparse. Therefore, the main objective of this dissertation is to reveal structural and …
Characterizing Body Fluids With Raman Spectroscopy : Towards Real World Application, Marisia Ann Fikiet
Characterizing Body Fluids With Raman Spectroscopy : Towards Real World Application, Marisia Ann Fikiet
Legacy Theses & Dissertations (2009 - 2024)
This project continues the research on a new method of body fluid identification and furthers its field capabilities. This method of identification uses Raman spectroscopy and advanced chemometrics to distinguish between body fluids. It is an improvement on current methods because it is confirmatory, non-destructive, and has simple sample preparation. The first objective of this research is to create a model for differentiating body fluids for a new desktop instrument. It was determined that due to resolution differences from a research grade instrument, a new model needed to be made for this the desktop instrument. This model will be able …
Synthesis Of Cadmium Arsenide Semiconductor Nanoparticles, Superatomic Silver Clusters, And Silver Coordination Polymers, Sarthak Jashubhai Patel
Synthesis Of Cadmium Arsenide Semiconductor Nanoparticles, Superatomic Silver Clusters, And Silver Coordination Polymers, Sarthak Jashubhai Patel
Legacy Theses & Dissertations (2009 - 2024)
Nanomaterials have chemical, electronic, optical, and other properties distinct from their bulk counterparts. However, the atom-precise synthesis of these materials remains a challenge, leaving open many scientific questions regarding the size regime between nanoparticulate (quantum confined) and bulk character. In this work, efforts toward the synthesis of nanoparticulate and atom-precise metal and semimetal materials are described. The synthesis of II-V semiconductor Cd3As2 having a near-zero bandgap is discussed. Analysis by UV-Vis absorption spectroscopy and powder X-ray diffraction indicate the formation of material with unexpected crystallinity and absorption properties The interaction between the molecular source of As and the solvent was …
Protein Ligation : Selenocysteine, Komal Shah
Protein Ligation : Selenocysteine, Komal Shah
Legacy Theses & Dissertations (2009 - 2024)
Selenium is present in human and animal body in the form of selenocysteine and
Evaluation Of Fingerprint Content For Forensic Crime Scene Analysis And Drug Metabolite Detection, Erica Kathryn Brunelle
Evaluation Of Fingerprint Content For Forensic Crime Scene Analysis And Drug Metabolite Detection, Erica Kathryn Brunelle
Legacy Theses & Dissertations (2009 - 2024)
With respect to criminal investigations, one key piece of evidence that often gets overlooked are fingerprints. For years, fingerprint samples have been believed to be useful only for matching purposes using their unique ridges, shapes, and sizes. With the rapid growth of forensic science, it has become evident that the development of fingerprint analysis has been stagnant. The traditional approach has been advantageous for the identification of many individuals; however, many fingerprint samples have been labeled “unusable” due to smudging, smearing, or any one of a myriad of reasons that could cause inconclusive matches. These samples can, however, still be …
Legislation To Reduce Microplastic Pollution : Understanding The Factors That Facilitated Passage Of The Federal Microbead-Free Waters Act Of 2015, Alyson Kelly Northrup
Legislation To Reduce Microplastic Pollution : Understanding The Factors That Facilitated Passage Of The Federal Microbead-Free Waters Act Of 2015, Alyson Kelly Northrup
Legacy Theses & Dissertations (2009 - 2024)
The full environmental impacts of microplastic pollution in aquatic environments remain uncertain, but several detrimental effects have been documented, including adverse health effects in multiple species and the susceptibility of microplastics to adsorb toxins and leach plastic additives. Plastic microbeads from rinse-off personal care products are a source of microplastic pollution that is introduced directly into the environment through runoff, including wastewater treatment plant effluent. In December 2015, the federal Microbead-free Waters Act of 2015 banned the manufacture and sale of all rinse-off personal care products containing plastic microbeads in the United States.
Sers For Protein Detection At A Single Molecule Level For Developing A New Medical Diagnostics Platform, Lamyaa Almehmadi
Sers For Protein Detection At A Single Molecule Level For Developing A New Medical Diagnostics Platform, Lamyaa Almehmadi
Legacy Theses & Dissertations (2009 - 2024)
A two-step process of protein detection at a single molecule level using Surface Enhanced Raman Spectroscopy (SERS) was developed as a new platform for medical diagnostics in this proof-of-concept study. First, a protein molecule was bound to a linker in the bulk solution and then this adduct was chemically reacted with the SERS substrate. Traut’s Reagent (TR) was used to thiolate Bovine serum albumin (BSA) in solution followed by chemical cross linking to a gold surface through a sulfhydryl group. A Glycine-TR adduct was used as a control sample to identify the protein contribution to the SER spectra. Gold SERS …
Defining And Harnessing Nature's Selection Of Geranylation In Rna Modification, Phensinee Haruehanroengra
Defining And Harnessing Nature's Selection Of Geranylation In Rna Modification, Phensinee Haruehanroengra
Legacy Theses & Dissertations (2009 - 2024)
Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. Geranylated-2-thiouridine is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, namely E. coli, E. aerogenes, P. aeruginosa and S. typhimurium by Liu group. It has been found as a post-transcription modification on the wobble position of anticodon of tRNAs specific for glutamic acid, glutamine and lysine. Geranylated-tRNA was shown to correct the frameshifting during the translation of E. coli. However, the reason of the existing of the modification is still largely unclear. To understand why nature incorporates such a hydrophobic group in …
Quantification Of Hemoglobin In Human Blood To Differentiate Individuals From One Another, Audrey Jeanne Auleley
Quantification Of Hemoglobin In Human Blood To Differentiate Individuals From One Another, Audrey Jeanne Auleley
Legacy Theses & Dissertations (2009 - 2024)
Blood is one of the principal sources of evidence in crime scene investigations. The level of hemoglobin in human blood is known to hardly fluctuate over time in a healthy adult patient. Using a method like the sodium lauryl sulfate (SLS) method for hemoglobin level determination is beneficial because SLS converts any other derivates of hemoglobin into methemoglobin. The amount of hemoglobin would be determined using the linear correlation between the absorbance of methemoglobin and its amount in blood samples. Those curves differ significantly from sample to sample. Therefore, a differentiation can be observed between the blood samples of different …
Saliva As A Diagnostic Biological Fluid And The Human Salivary Proteome, Jessica Ghassan Emsies
Saliva As A Diagnostic Biological Fluid And The Human Salivary Proteome, Jessica Ghassan Emsies
Legacy Theses & Dissertations (2009 - 2024)
Saliva is a unique biologic fluid that contains a varying spectrum of proteins, nucleic acids, electrolytes, and hormones.31 It is an exocrine secretion of the salivary glands which is hypotonic in nature with a pH of 7.2-7.4.31 Saliva plays an important role in the oral cavity.33 It lubricates, hydrates, and bathes the oral cavity, therefore, aiding speech and mastication.33 Saliva forms a barrier on the teeth, protects against demineralization, and aids in remineralization.33 Saliva is required for chewing and food bolus preparation, it contains enzymes necessary for digestion, and mediates the sense of taste.33 It also helps wound healing and …
Synthesis And Adsorption Experiments With Metal-Organic Frameworks For High School And Undergraduate Laboratory Settings, Kate Holley
Legacy Theses & Dissertations (2009 - 2024)
Seven experiments are described and outlined here that introduce high school and undergraduate students to metal–organic frameworks (MOFs) and their applications. The experiments were designed to be completed with basic laboratory equipment and supplies and without the use of expensive characterization instruments, simulating typical high school chemistry laboratory conditions. Students synthesized two well-known MOFs, HKUST-1 and aluminum fumarate, using simple, safe, and rapid methods (fast enough to be performed within the time constrains of a typical high school class). Students then use their synthesized MOFs to explore their inherent sorption properties. In one set of experiments, the synthesized MOFs are …
Accumulation And Spatial Distribution Of Lead And Other Trace Elements In Keratinized Tissues : Investigations Based On Analytical Atomic Spectrometry, Mina W. Tehrani
Accumulation And Spatial Distribution Of Lead And Other Trace Elements In Keratinized Tissues : Investigations Based On Analytical Atomic Spectrometry, Mina W. Tehrani
Legacy Theses & Dissertations (2009 - 2024)
Human biomonitoring for toxic metals such as lead (Pb) provides information about absorbed dose from all exposure routes, and is critical for identifying exposed individuals and assessing health risks. Blood Pb and bone Pb are the primary validated biomarkers for assessing short-term and historical Pb exposures, respectively, while non-traditional matrices, including keratinized tissues, can provide complementary exposure information. Hard keratinized tissues – including hair, nails, hooves, and horns – grow incrementally, potentially preserving chemical exposure histories over a span of days to years. Analytical limitations and poor interlaboratory reproducibility, however, have led to debate around the use of human nails …
Study Of Small Molecules With Dna Monolayers On Gold Electrodes Using Electrochemical Quartz Crystal Microbalance On The Millisecond Timescale, Sarasi Kaushalya Kumari Galagedera
Study Of Small Molecules With Dna Monolayers On Gold Electrodes Using Electrochemical Quartz Crystal Microbalance On The Millisecond Timescale, Sarasi Kaushalya Kumari Galagedera
Legacy Theses & Dissertations (2009 - 2024)
Biosensors based on DNA self-assembled monolayers (SAMs) combined with electrochemical transducers have shown great potential to serve an important role in simple, accurate and inexpensive genetic analyses relevant to many fields. The most popularly adapted method in designing biosensing platforms is the self-assembly of 5’-alkylthiol-modified single stranded or double stranded DNA on gold surfaces followed by a passivation step using a diluent like mercaptohexanol (MCH). Since analytical performance (sensitivity, selectivity and stability) of such sensors is solely related to the probe surface architecture, methods to characterize and measure the surface density has gained a lot of interest among the scientific …
Computational Modeling As A Tool For Designing Ligands And Receptors, Waqas S. Awan
Computational Modeling As A Tool For Designing Ligands And Receptors, Waqas S. Awan
Legacy Theses & Dissertations (2009 - 2024)
Computational methods can be used for a wide range of applications, especially regarding DNA and RNA. Interactions such as sugar torsions, receptor-ligand interactions, ligand docking/drug docking, receptor modeling, and drug design are excellent candidates for computational analysis and in silico experiments. The use of molecular dynamics software (GROMACS) coupled with molecular design software (MOE) produce insights that may have been otherwise difficult to assess. All these problems are academic in nature but have practical uses outside of academia. Understanding alternate linkages can lead to antibiotic assays to address potential superbug epidemics. Modeling DNA superstructures can provide insight into how large …
Extreme Molecular Diversity In Biomass Burning Atmospheric Organic Aerosol Observed Through Ultrahigh Resolution Mass Spectrometry, Matthew Brege
Extreme Molecular Diversity In Biomass Burning Atmospheric Organic Aerosol Observed Through Ultrahigh Resolution Mass Spectrometry, Matthew Brege
Dissertations, Master's Theses and Master's Reports
Ambient atmospheric aerosol is ubiquitous in the atmosphere, originating from a variety of natural and man-made sources. These microscopic particles have profound impacts on the global climate system as well as human health. The organic fraction of atmospheric aerosol is an extremely complex mixture which is not yet fully characterized. These unknown organic aerosol species contribute to the uncertainty in the effect of aerosol on climate and uncertainty in overall ambient aerosol toxicity. Light absorbing organic aerosol can interact with incoming solar radiation and contribute to atmospheric heating; however, the source apportionment and overall fate of these absorbing organic aerosol …
Insights Into Gemcitabine Resistance And The Potential For Therapeutic Monitoring, Teklab Gebregiworgis, Fatema Bhinderwala, Vinee Purohit, Nina V. Chaika, Pankaj K. Singh, Robert Powers
Insights Into Gemcitabine Resistance And The Potential For Therapeutic Monitoring, Teklab Gebregiworgis, Fatema Bhinderwala, Vinee Purohit, Nina V. Chaika, Pankaj K. Singh, Robert Powers
Department of Chemistry: Faculty Publications
Introduction—Gemcitabine is an important component of pancreatic cancer clinical management. Unfortunately, acquired gemcitabine resistance is widespread and there are limitations to predicting and monitoring therapeutic outcomes.
Objective—To investigate the potential of metabolomics to differentiate pancreatic cancer cells that develops resistance or respond to gemcitabine treatment.
Results—We applied 1D 1H and 2D 1H-13C HSQC NMR methods to profile the metabolic signature of pancreatic cancer cells. 13C6-glucose labeling identified thirty key metabolites uniquely altered between wild-type and gemcitabine-resistant cells upon gemcitabine treatment. Gemcitabine resistance was observed to reprogram glucose metabolism and to enhance the pyrimidine …
Detailed Characterization Of The Solution Kinetics And Thermodynamics Of Biotin, Biocytin And Haba Binding To Avidin And Streptavidin, Roberto F. Delgadillo, Timothy C. Mueser, Kathia Zaleta-Rivera, Katie A. Carnes, Jose Gonzalez-Valdez, Lawrence J. Parkhurst
Detailed Characterization Of The Solution Kinetics And Thermodynamics Of Biotin, Biocytin And Haba Binding To Avidin And Streptavidin, Roberto F. Delgadillo, Timothy C. Mueser, Kathia Zaleta-Rivera, Katie A. Carnes, Jose Gonzalez-Valdez, Lawrence J. Parkhurst
Department of Chemistry: Faculty Publications
The high affinity (KD ~ 10−15 M) of biotin for avidin and streptavidin is the essential component in a multitude of bioassays with many experiments using biotin modifications to invoke coupling. Equilibration times suggested for these assays assume that the association rate constant (kon) is approximately diffusion limited (109 M-1s-1) but recent single molecule and surface binding studies indicate that they are slower than expected (105 to 107 M-1s-1). In this study, we asked whether these reactions in solution are diffusion controlled, which reaction model and thermodynamic …
Coumarin-Based Benzilmonohydrazone As A New Proton-Sensitive Fluorescence Dye: Synthesis And Investigation Of Photophysical And Acidochromic Properties, Burcu Aydiner
Turkish Journal of Chemistry
Coumarin-based chromogenic and fluorogenic dye 4 was designed and synthesized. The photophysical properties of 4 were determined in solvents with different polarities. Protonation affinity was determined by adding trifluoroacetic acid (TFA) to a dichloromethane solution of dye 4 utilizing the UV-Vis and fluorescence titration methods. The protonation region was investigated by using the $^{1}$H NMR method. Additionally, DFT and TDDFT studies were performed to support the structural and absorption spectral properties of 4.
Silylation Of Epoxidized Soybean Oil With Triethoxysilanes, Synthesis And Characterization Of Their Polyurethanes, Aynur Özşeker, Kemal Karadeni̇z, Mustafa Yasi̇n Şen
Silylation Of Epoxidized Soybean Oil With Triethoxysilanes, Synthesis And Characterization Of Their Polyurethanes, Aynur Özşeker, Kemal Karadeni̇z, Mustafa Yasi̇n Şen
Turkish Journal of Chemistry
Silylation of epoxidized soybean oil (ESBO) was carried out by epoxy ring opening reaction of methoxy and ethoxy silane compounds. $^{1}$H NMR and FTIR spectra confirmed that two novel bio-based polyols, PSiTh and PSiAm, were obtained through the ring opening of epoxy by the mercapto and amino moieties of MPTMS and APTES, respectively. Polyurethanes of these polyols were prepared using 4,4'- methylene-bis(phenyl isocyanate) (MDI) to incorporate silanol groups into polymer network and were labeled as PUSiTh and PUSiAm, respectively. To see the impact of silanol and phosphorous groups on flame retardant properties, the chain extended polyurethanes, PUSiThCE and PUSiAmCE were …
Ann-Assisted Forecasting Of Adsorption Efficiency To Remove Heavy Metals, Magdi Buaisha, Şazi̇ye Balku, Şeni̇z Özalp Yaman
Ann-Assisted Forecasting Of Adsorption Efficiency To Remove Heavy Metals, Magdi Buaisha, Şazi̇ye Balku, Şeni̇z Özalp Yaman
Turkish Journal of Chemistry
In wastewater treatment, scientific and practical models utilizing numerical computational techniques such as artificial neural networks (ANNs) can significantly help to improve the process as a whole through adsorption systems. In the modeling of the adsorption efficiency for heavy metals from wastewater, some kinetic models have been used such as pseudo first-order and second-order. The present work develops an ANN model to forecast the adsorption efficiency of heavy metals such as zinc, nickel, and copper by extracting experimental data from three case studies. To do this, we apply trial-and-error to find the most ideal ANN settings, the efficiency of which …
Sensitive Biological Detection Based On Langmuir--Blodgett Films Prepared From Diluted Silica Suspensions, Numan Gözübenli̇
Sensitive Biological Detection Based On Langmuir--Blodgett Films Prepared From Diluted Silica Suspensions, Numan Gözübenli̇
Turkish Journal of Chemistry
Self-assembled three-dimensional (3-D) colloidal crystals have been extensively utilized in nanolithography for fabricating a wide spectrum of functional periodic nanostructures for important technological applications. Here a simple and versatile way is reported using silica colloids to prepare close-packed particle multilayers by the Langmuir--Blodgett technique to create highly ordered 3-D colloidal crystals with unusual nanoarrays on a large variety of substrates. Successive deposition of monolayers using amphiphilic molecules in this approach allows control of the layer thickness, particle size, and especially packing structure of them in each layer. It has been demonstrated that the Langmuir--Blodgett film's transparency and high antiglare optical …
Robert J. Lefkowitz And Discovery Of The G-Protein-Coupled Receptor Family, Clarence Lee
Robert J. Lefkowitz And Discovery Of The G-Protein-Coupled Receptor Family, Clarence Lee
Natural Sciences Student Research Presentations
This poster for the Natural Sciences Poster Session at Parkland College features Dr. Robert J. Lefkowitz, 2012 Nobel Prize in Chemistry winner (with Brian Kobilka) for their research on G-protein-coupled receptors, proteins in the plasma membrane that allow for the transmission of information through the membrane and into the cell. This research was to impact the development of medications that target these receptors, such as SSRIs.
Evaluating Green Solvents And Techniques In Extraction Methods, Shanmugapriya Dharmarajan
Evaluating Green Solvents And Techniques In Extraction Methods, Shanmugapriya Dharmarajan
Electronic Theses and Dissertations
Of all analytical techniques, extraction is a huge solvent-consuming process that could adversely impact the environment. Use of petroleum-based solvents for extraction of oilseeds is still a common practice, despite the potential fire hazard and the toxic water pollution. The rising awareness of chemical activities created immense need for sustainable development schemes and strategies that should address the environmental impact without compromising the yield. In the course of developing green extraction techniques, automation, alternative solvents, and selective extractions are the growing trend. This dissertation aligns with that progress by surveying green solvents, comparing their performance during oil extraction, examining a …
Theranostics Based On Linear Dendritic Block Copolymers, Jon Williams
Theranostics Based On Linear Dendritic Block Copolymers, Jon Williams
Electronic Theses and Dissertations
When combining imaging and therapeutic motifs, known as theranostics, amphiphilic diblock copolymers have a strong precedent of success. These polymers can self-assemble into a variety of morphologies that are known to concentrate in areas of inflammation such as tumors. However, prediction of size and morphology from polymer structure still remains an open challenge. Another system with promise of therapeutic efficacy are tree-like struc- tures known as dendrimers, such as poly(amidoamine) (PAMAM) and bis-(hydroxymethyl) propionic acid (bMPA), which can uptake drugs and dyes into their branches. It is desireable to combine these two motifs, using linear-dendritic block copolymers (LDBCs). These represent …
Chemical Synthesis Of Galacto-Oligosaccharides And Evaluation Of Their Prebiotic Properties, Pranpariya Ponpakdee
Chemical Synthesis Of Galacto-Oligosaccharides And Evaluation Of Their Prebiotic Properties, Pranpariya Ponpakdee
Chulalongkorn University Theses and Dissertations (Chula ETD)
Galacto-oligosaccharides (GOS) are composed of galactose and glucose between 2–8 units or disaccharide comprising 2 units of galactose linked by glycosidic bonds. GOS exhibits prebiotic activity and widely used in infant formula. Commercial GOS was achieved as mixture by enzymatic synthesis of lactose with β-galactosidase. Due to the nature of the enzymatic derived-GOS, the structure-activity relationship of GOS and prebiotic activity is mainly ambiguous. In this work, we presented the development towards a production of GOS by chemical synthesis starting from lactose. First, lactose was isolated from liquid whey with 3.90% w/v recovery. Lactose was then hydrolyzed to produce galactose …
Synthesis And Photocatalytic Activity Of Ag-Tio2 For Organic Compound Removal, Tri Rahmawati
Synthesis And Photocatalytic Activity Of Ag-Tio2 For Organic Compound Removal, Tri Rahmawati
Chulalongkorn University Theses and Dissertations (Chula ETD)
Organic pollutants such as dyes and volatile organic compounds which are widely used materials in industries and discharged daily to the aqueous environment can be harmful to human health. This present study proposed an environmentally friendly approach for silver-doped titanium dioxide (Ag-TiO2) synthesis as a photocatalyst material used as photocatalytic organic pollutant degradation. The synthesis of Ag-TiO2 was conducted by using dry and wet ball milling sol−gel method with the aqueous extract of turmeric powder under 6000C calcination. The effect of different Ag contents of 0.5%, 1%, 3%, and 6% in Ag-TiO2 on the degradation of the organic pollutants was …
การย่อยสลายด้วยเอนไซม์ของพอลิเอสเทอร์ไมโครไฟเบอร์ที่ได้จากการซักผ้าสปันพอลิเอสเทอร์, โกมลชนก ผลาหาญ
การย่อยสลายด้วยเอนไซม์ของพอลิเอสเทอร์ไมโครไฟเบอร์ที่ได้จากการซักผ้าสปันพอลิเอสเทอร์, โกมลชนก ผลาหาญ
Chulalongkorn University Theses and Dissertations (Chula ETD)
งานวิจัยนี้แสดงการผลิตเอนไซม์เอสเทอเรสที่มีค่าแอกติวิตีสูงสุด 9,200 ยูนิตต่อมิลลิลิตร จากเชื้อแอกติโนมัยซีส Thermobifida sp. เพื่อนำไปย่อยสลายเศษเส้นใยพอลิเอสเทอร์ที่ได้จากการซักผ้าสปันพอลิเอสเทอร์โดยศึกษาผลกระทบของพีเอชและอุณหภูมิต่อค่าแอกติวิตีของเอนไซม์ ศึกษาภาวะที่เหมาะสมสำหรับการย่อยสลายเศษเส้นใย ได้แก่ อุณหภูมิ พีเอช เวลา และความเข้มข้นของเอนไซม์ จากการทดลองพบว่า พีเอชและอุณหภูมิ ที่ทำให้เอนไซม์เอสเทอเรสมีค่าแอกติวิตีสัมพัทธ์สูงสุดคือ พีเอช 9 (ทริสไฮโดรคลอริกบัฟเฟอร์) และ อุณหภูมิ 55 องศาเซลเซียส และเป็นภาวะที่เอนไซม์เอสเทอเรสมีความเสถียร เมื่อนำเอนไซม์เอสเทอเรสที่ความเข้มข้น 25–100 เปอร์เซ็นต์ (ปริมาตรต่อปริมาตร) ไปย่อยสลายเศษเส้นใยพอลิเอสเทอร์ เป็นเวลา 1-7 วัน แล้วนำสารละลายหลังการย่อยสลายมาวิเคราะห์หาชนิด และปริมาณผลิตภัณฑ์ที่เกิดขึ้น (TPA, EG, BHET) รวมทั้งศึกษาสมบัติของเศษเส้นใยพอลิเอสเทอร์หลังการย่อยสลายโดยใช้เทคนิค SEM XRD และ FT-IR พบว่า สารละลายหลังการย่อยสลายเศษเส้นใยพอลิเอสเทอร์ 0.05 กรัม ด้วยเอนไซม์ 75 เปอร์เซ็นต์ (ปริมาตรต่อปริมาตร) ที่พีเอช 9 และ อุณหภูมิ 55 องศาเซลเซียส เป็นเวลา 5 วัน ที่ถูกวิเคราะห์ด้วยเทคนิค UV-Vis Spectrophotometry แสดงปริมาณ TPA ที่เกิดขึ้นสูงสุดที่ 49.05 ไมโครกรัมต่อมิลลิลิตร ในขณะที่การวิเคราะห์สารละลายหลังการย่อยสลายที่ภาวะข้างต้นโดยใช้เทคนิค HPLC-UV detector แสดงปริมาณ TPA ที่ 11.19 ไมโครกรัมต่อมิลลิลิตร และ BHET ที่ 13.27 ไมโครกรัมต่อมิลลิลิตร และการวิเคราะห์โดยใช้เทคนิค HPLC-RI detector พบปริมาณ EG ในสารละลายที่ 446.71 ไมโครกรัมต่อมิลลิลิตร ส่วนการวิเคราะห์เศษเส้นใยพอลิเอสเทอร์ด้วยเทคนิค SEM หลังการย่อยสลายด้วยเอนไซม์เอสเทอเรส 75 เปอร์เซ็นต์ (ปริมาตรต่อปริมาตร) ที่ภาวะข้างต้น พบว่า เศษเส้นใยถูกทำลายและมีพื้นผิวขรุขระเป็นบริเวณกว้างมากกว่าเศษเส้นใยที่ผ่านการย่อยสลายด้วยเอนไซม์ที่ภาวะอื่นๆ นอกจากนั้นยังพบว่าการวิเคราะห์เศษเส้นใยพอลิเอสเทอร์ก่อนและหลังการย่อยสลายด้วยเอนไซม์ด้วย FTIR ปรากฎพีกที่คล้ายคลึงกัน …