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Articles 61 - 83 of 83
Full-Text Articles in Chemistry
Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo
Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo
Electronic Theses and Dissertations
Heart disease is the leading cause of death in the United States. Understanding heart function at the molecular level is critical for developing of more effective treatments. In the cardiac muscle, the thin filament is composed by troponin (Tn), tropomyosin (Tm), and F-actin. It provides Ca2+-dependent regulation of contraction by modulating myosin attachment and force generation in a cooperative scheme. However, this mechanism remains unclear. To understand thin filament activation, we studied the binding and functional properties of Tn and Tm to F-actin at single particle resolution by employing fluorescence image colocalization, in vitro motility assays, and Förster resonance energy …
Mechanistic Studies Of The Structure-Photostability Relationship Of Organic Conjugated Polymers, Logan Paul Sanow
Mechanistic Studies Of The Structure-Photostability Relationship Of Organic Conjugated Polymers, Logan Paul Sanow
Electronic Theses and Dissertations
Organic Conjugated polymers (CPs) are a subject of intense research for their application in organic photovoltaics (OPVs), organic light emitting diodes (OLEDs), solid-state dye lasing, biological imaging and sensing, chemical sensing and remote sensing. CPs are key materials in the quest for more sustainable forms of renewable energy, making electronics more versatile and light weight, and increasing the functionality of everyday materials. For these applications and others that use CPs as the photoactive material, one of their main drawbacks is their susceptibility to photodegradation. Photodegradation occurs when the material is exposed to light leading to irreversible changes in the materials, …
Ice Concentration Linked With Extractive Stirrer (Icecles), Nujud Omar Maslamani
Ice Concentration Linked With Extractive Stirrer (Icecles), Nujud Omar Maslamani
Electronic Theses and Dissertations
Clean water is very important for human health. Therefore, drinking water contamination is a significant research concern, especially with the increasing global population. Some contaminants, such as pesticides, can cause health effects even at low levels. Therefore, trace and ultratrace analysis of contaminants in drinking water is essential. Ultratrace analysis typically requires highly effective sample preparation methods and/or highly sensitive instruments. There are currently advanced sample preparations techniques available to analytical chemists that may allow trace analysis of certain analytes. These include liquid-liquid extraction (LLE), solid phase extraction (SPE), solid phase micro extraction (SPME), and stir bar sorpitive extraction (SBSE). …
Use Of Extraction Technologies In Food Safety Studies, Changling Qiu
Use Of Extraction Technologies In Food Safety Studies, Changling Qiu
Electronic Theses and Dissertations
Food safety has become a top concern in our society. The public in general is increasingly concerned about the safety of the food products they consume every day as more and more food contamination incidents and widespread recalls arise. It is necessary to trace any presence and/or the concentration levels of contaminants, pesticides, herbicides, or other harmful substances in food samples. Sample preparation is a crucial step in a food analytical method, as it takes up most of the total analysis time, contributing highly to the total cost of analysis and greatly influencing the results of the analysis. Traditional extraction …
Nanofiltration Membrane Pilot Studies For Disinfection By-Product Control, Eric J. Lynne
Nanofiltration Membrane Pilot Studies For Disinfection By-Product Control, Eric J. Lynne
Electronic Theses and Dissertations
Watertown, South Dakota currently uses conventional softening to treat ground water to remove hardness, iron and manganese, and natural organic matter. The distribution system has experienced elevated concentrations of disinfection by-products, which will require additional treatment to comply with future limits set by the Stage 2 Disinfectant/Disinfection By-Products Rule. A nanofiltration membrane system has been proposed to remove additional natural organic matter from the softened water. Removing the natural organic material disinfection by-product precursors should reduce the concentration of disinfection by-products. The use of nanofiltration membranes has been previously documented to reject total organic carbon, while allowing desirable levels of …
The Phosphacylium Ion: Evidence For Its Existence As An Intermediate In Reactions Of Organophosphates, Thomas D. Matus
The Phosphacylium Ion: Evidence For Its Existence As An Intermediate In Reactions Of Organophosphates, Thomas D. Matus
Electronic Theses and Dissertations
Prior to this work, no strong evidence existed which unequivocably proved the existence of phosphacylium ions as intermediates in reactions of this type. It is the object of this study to look into nucleophilic substitution at phosphorus, and the intermediates of these possible dissociative type reactions.
Nucleophilic Substitution At Phosphorus In Six-Membered Ring Phosphate Esters, Mike Bauman
Nucleophilic Substitution At Phosphorus In Six-Membered Ring Phosphate Esters, Mike Bauman
Electronic Theses and Dissertations
From these results the following conclusions may be drawn: 1. The stereochemistry of nucleophilic substitution at phosphorus is influenced by the basicity of the leaving group with the more basic leaving group favoring retention. 2. Lithium ion diverts the reaction to retention by forming an intimate ion-pair with the nucleophile which then attacks phosphorus. This associated ion is less reactive than the unassociated nucleophile. 3. For the retention mechanism the leaving group participates in the rate determining step. 4. The mechanism for retention entails a more sterically unfavorable configuration than for inversion.
Specificity Of Antisera Against Hordeum Vulgare Ribonuclease And Serological Quantitation Of The Enzyme In Tissue Extracts, Steven Bryan Hawthorne
Specificity Of Antisera Against Hordeum Vulgare Ribonuclease And Serological Quantitation Of The Enzyme In Tissue Extracts, Steven Bryan Hawthorne
Electronic Theses and Dissertations
Specific rabbit antisera against purified seedling RNase I from both a hardy (Dicktoo) and less-hardy (Tennessee Winter) cultivar of winter barley was obtained using a 1 mg injection schedule. Both antisera formed a single precipitin band on double immunodiffusion and immunoelectrophoresis when reacted with the homologous crude tissue extract. RNase antigen from either cultivar was highly cross-reactive with both antisera. Passive hemagglutination inhibition was used in an attempt to distinguish purified RNase from both cultivars. A consistent difference in anti-RNase serum specificity between cultivars was shown, but the difference observed by this method was not sufficient to conclude structural differences …
Studies On The Gas Given Off By Yeast When It Goes From An Anaerobic To Aerobic Metabolism, David C. Potts
Studies On The Gas Given Off By Yeast When It Goes From An Anaerobic To Aerobic Metabolism, David C. Potts
Electronic Theses and Dissertations
Several investigators have observed that when yeast cells (yeast) go from a strictly anaerobic environment to an aerobic oner and glucose is added a negative value is recorded on the manometer. This phenomenon indicates that a gas has been given off by the yeast. The purpose of this research was to identify the gas and determine how it arises.
Molybdenum(V) Solutions In Hydrobromic Acid, Edwin Charles Perley
Molybdenum(V) Solutions In Hydrobromic Acid, Edwin Charles Perley
Electronic Theses and Dissertations
Interest in the coordination chemistry of molybdenum has increased greatly in recent years because of the discovery that molybdenum plays an active role in several redox enzymes. Model systems have been devised to gain insight into the function of molybdenum in these enzymes. Most model systems are believed to contain an oxomolybdate(V) dimer in equilibrium with a redox active monomer or dimer. A relatively simple system that shows important similarities to model systems is a molybdenum(V) solution in hydrobromic or hydrochloric acid. As in the model systems, these solutions are believed to contain monomers and dimers in equilibrium. The equilibria …
Tetrazoline Chemistry, Norman Wallace Rokke
Tetrazoline Chemistry, Norman Wallace Rokke
Electronic Theses and Dissertations
It was of interest to investigate the chemistry of some tetrazolines since they might be sources of heteroatomic analogues of trimethylenemethane. In addition, they might provide alternate means of synthesis of small ring compounds such as diaziridinones and diaziridineimines. New compounds which were prepared are 1-(2,6-dimethylphenyl) tetrazoline-5-one, 1-(2,6-dimethylphenyl)-4-methyltetrazoline-5-one, l-phenyl-4-methyl-5-iminotetrazoline, l-phenyl-4-methyl-5- methyliminotetrazoline, and l-phenyl-4-methyl-5-methyliminotetrazoline methiodide. The mass spectra of the tetrazolines investigated are characterized by ring fragmentations which are helpful in determining their structure. In addition, fragmentation represents one of the few examples of a retro-1,3-dipolar cycloaddition reaction initiated by electron impact. The monosubstituted tetrazolines are thermally unstable. The course of …
Nucleophilic Substitution At Phosphorus: Phosphate Thioesters, Ronnie L. Wilde
Nucleophilic Substitution At Phosphorus: Phosphate Thioesters, Ronnie L. Wilde
Electronic Theses and Dissertations
It was my objective to try to determine the mechanism of nucleophilic substitution at phosphorus in monothiophosphate triesters and to apply what I learn to the other phosphate systems. I also tried to obtain more data to show that the Lewis acid-base type complex through the phosphoryl oxygen is existent and does influence the reaction.
Interactions Of Rhenium(V) Chloride And Oxotrichlorobis(Triphenlyphosphine)Rhenium(V) With Selected Solvents, Paul Luther Holm
Interactions Of Rhenium(V) Chloride And Oxotrichlorobis(Triphenlyphosphine)Rhenium(V) With Selected Solvents, Paul Luther Holm
Electronic Theses and Dissertations
The purpose of this study was to examine the solution interactions of rhenium(V) chloride and oxotrichlorobis(triphenylphosphine)rhenium(V) in a continuation of studies of rhenium(V) chemistry. These goals were accomplished using vacuum line and Schlenk tube techniques. As a result of this work, rhenium(V) chloride was found to dissolve with reaction in 1, 4-dioxane, diethyl ether and acetone. There was only a very small amount of rhenium(V) chloride which dissolved in carbon tetrachloride, chloroform and cyclohexane. Part of what did dissolve was shown by electronic and infrared spectroscopy to be oxotetrachlororhenium(VI) which was present as an impurity in small amounts. Oxotetrachlororhenium(VI) reacts …
A Study Of Oxomolybdenum Chelate Compounds Of Oxidation States (V) And (Iv) When Prepared By Photochemical Reduction Of Oxomolybdenum (Vi) Complexes In Ethanol Under Inert Atmosphere And By Chemical Reduction, Richard Donald Dendinger
A Study Of Oxomolybdenum Chelate Compounds Of Oxidation States (V) And (Iv) When Prepared By Photochemical Reduction Of Oxomolybdenum (Vi) Complexes In Ethanol Under Inert Atmosphere And By Chemical Reduction, Richard Donald Dendinger
Electronic Theses and Dissertations
A photolysis system was designed for meticulous exclusion of oxygen and moisture. Photolyzed ethanol solutions of dioxobis(acetylacetonato)-molybdenum(VI), Mo02 (acac)2, were studied via preparation of derivatives with several uninegative bidentate ligands (chelH, cysteine was designated cystH2) and pyridine (py). Infrared spectroscopy was a useful tool in identifying these compounds. An oxomolybdenum(IV) compound, MoO(dtc)2 was isolated from the red photolyzed solution when dtc was the N,N-diethyldithiocarbamate ion. Tropolone, 8-hydroxyquinoline, N,N-diethyldithiocarbamate, and cysteine formed products formulated as the dioxo bridged molybdenum(V) compounds, Mo204(che1)2. Acetylacetone, tropolone, 8-Hydroxyquinoline and N,N-diethyldithiocarbamate, formed derivatives formulated …
A Study Of Bisimines Of Tetramethyl-1,3-Cyclobutanedione, Edward Albert Schmidt
A Study Of Bisimines Of Tetramethyl-1,3-Cyclobutanedione, Edward Albert Schmidt
Electronic Theses and Dissertations
It was the purpose, therefore, of this work, to investigate the preparation, properties, and reactions of bisimines of 2,2,4,4- tetramethyl-1,3-cyclobutanedione, to determine the chemical effects of carbon π-bonded to nitrogen. Certain of these effects are compared to carbon π-bonded to oxygen in a structurally similar environment.
The Primary Structure Of Nifungin, Marvin Lee Withrow
The Primary Structure Of Nifungin, Marvin Lee Withrow
Electronic Theses and Dissertations
The primary structure of the antifungal peptide nifungin was studied. Amino acid analysis of nifungin before and after performic acid oxidation revealed 51 amino acids and the presence of an unidentified ninhydrin positive material. The unidentified material constituted approximately ten per cent of nifungin by weight. It contains nitrogen but, as reported by others (2), did not contain phosphate or reducing sugars. It was not hydrolyzed into smaller compounds by strong mineral acids. Carboxyl terminal analysis was conducted utilizing carboxy-peptidase A and B on both the oxidized and unoxidized nifungin. Tyrosine appeared to be released most rapidly followed by lysine, …
Applications Of New Methods Of Structure Determination, Richard Earl Wagner
Applications Of New Methods Of Structure Determination, Richard Earl Wagner
Electronic Theses and Dissertations
The structures of: 1) 2-piperidino-5-chlorornethyl-5-rnethyl-2- oxo-1, 3,2-dioxaphosphorinan; 2) 2-phenoxy-5-chloromethyl-5-methyl-2- oxo-1, 3,2-dioxaphosphorinan; 3) 2-p-bromophenoxy-5-chloromethyl-5- chloromethyl-5-methyl-2-oxo-1, 3, 2-dioxaphosphorinan have been resolved by x-ray single crystal studies. A Picker 4 circle diffractometer employing molybdenum x-rays and a zirconium filter was used to obtain accurate data. The space group of the first two compounds is P21/c while that of the third is Pca21. The lattice constants of the compounds are: 1) a = 10.035(8)Å, b = 6.503(4), c = 20.19(1), β = 96.8(3)°; 2) a = 6.237(3)Å, b = 11.437(5), c = 19.419(9), β = 109.95(3); and 3) a = …
The Chemistry Of Some Unusual Carbodiimides, Donald Melvin Plautz
The Chemistry Of Some Unusual Carbodiimides, Donald Melvin Plautz
Electronic Theses and Dissertations
Several N1-alkyl-N2-(N,N-dialkylamino)carbodiimides, which were found to form dimeric species, were prepared, and the structure of the dimeric species determined. A study of the reaction chemistry of both the monomeric and dimeric carbodiimides led to the conclusion that dimerization occurred via a (π2s + π2a) ground-state, symmetry-allowed mechanism, and that thermal decomposition of the dimeric species occurred via a (π2s +-π2s) excited-state, symmetry-allowed mechanism. Although dialkylphosphoramidates have been shown to be useful intermediates in the preparation of unsaturated organic nitrogen compounds, N-acyl- and N-imino-dialkylphosphorohydrazidates were found to be too unstable, forming trialkylphosphates upon distillation, to be of …
Separation Of The Selenium Compounds In Seleniferous Plant Protein Hydrolysates By Paper Partition Chromatography, Arnold L. Smith
Separation Of The Selenium Compounds In Seleniferous Plant Protein Hydrolysates By Paper Partition Chromatography, Arnold L. Smith
Electronic Theses and Dissertations
In 1943 Franke reported that the protein of "allolied" or "toxic" wheat carried the toxicant, and Franke and Painter in 1935 reported that those "toxic" proteins contained selenium which was in organic combination in the protein. There has been much speculation regarding the possibility of selenium replacing sulfur in the amino acids cysteine and methionine. The toxicity of selenium in selenium analogs of these compounds is similar to that of selenium occurring naturally in proteins seleniferous cereals, which indicated that the selenium may be present in the proteins as the analogue of these sulfur amino acids.
The Effects Of Certain Salts Upon The Saccharogenic Activity Of Three Typical Enzymes, George F. Gastler
The Effects Of Certain Salts Upon The Saccharogenic Activity Of Three Typical Enzymes, George F. Gastler
Electronic Theses and Dissertations
In a previous investigation carried out in these laboratories, Moxon and Franks (1), have shown the toxicity of sodium salts of selenium, vanadium, arsenic and tellurium toward the production of carbon dioxide during yeast fermentation of glucose. The toxicity of the salts occurred in the order given. In the same investigation (1), it was shown that sodium sulfide and sodium sulfite exert an accelerating effect.
An Investigation Into The Bromate Method Of Manganese Determination, Ray A. Bunday
An Investigation Into The Bromate Method Of Manganese Determination, Ray A. Bunday
Electronic Theses and Dissertations
Throughout the history of research in the science of Chemistry the problem of the quantitative determination of manganese has always been a perplexing one. The results have usually fallen short of the theoretical value and has necessitated the application of an empirical factor(1) which is always undesirable to the true research scientist, if not to the commercial analyst.
Selenium In Proteins From Toxic Foodstuffs, Edgar Page Painter
Selenium In Proteins From Toxic Foodstuffs, Edgar Page Painter
Electronic Theses and Dissertations
The importance of the selenium problem has been established. Knight (1) in an address before The Association of Official Agricultural Chemists summarized the progress made on the problem, conservatively emphasized its importance, and stressed the need for extensive research. It is a paramount problem not only in South Dakota, but in many other states as well.
Determination Of The Limits And Accuracy Of Potassium Ferricyanide As An Outside Indicator In The Determination Of Iron And A Comparison Of This Outside Indicator With Diphenylamine As An Inside Indicator, Eugene D. Burr
Electronic Theses and Dissertations
In the volumetric course as offered by the Department of Chemistry of South Dakota State College for the spring term of 1931, we experienced difficulties in the methods which we were using for the determination of iron. The general method used was that of Penny's, using an outside indicator of potassium ferricyanide, and titrating with potassium dichromate.