Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 20 for “"weak acids"”.
-
Evaluating the Ability of Different Weak Acids When Combined with Hydrogen Peroxide to Develop Latent Fingerprints on Post-Fired Cartridge Cases
… study examined the effectiveness of different weak acids in developing fingerprints on different types of cartridge cases when combined with hydrogen peroxide due to a process known as chemical etching. Chemical etching involves an oxidation-reduction in which the metal is oxidized by the acid. …
-
The Dissociation Constant of Acetic Acid at 25°c
The dissociation constants of weak acids can be determined from thermodynamic data obtained from cells without liquid junction. The method was developed by Harned and his students.
-
ACID-BASE REACTIONS IN DIFFERENT SOLID-STATE FORMS
Most drug substances are reported to be either weak acids or weak bases. Hence, acid-base reactions are commonly observed in pharmaceutical systems with samples including salts, amorphous solid dispersions, and in formulated products. Salt formation of active pharmaceutical ingredients (APIs) is …
-
The production of 4-adminobutyrate in response to treatments reducing cytosolic pH and the regulation of intracellular pH
… GABA + C02), and compared to many free amino acids is present in high concentrations in plant cells. GABA levels rise rapidly and dramatically in response to varied stress conditions including anaerobiosis. Recent papers suggest that GABA production and associated H+ consumption are parts of a …
-
Relationships Between Proton Translocation, Absorption Changes, and Photocurrents in the Bacteriorhodopsin Photocycle
… could be lowered by addition of azide and other weak acids. Weak acids accelerated the decay of O in wild type bR at low pH as well. Finally, charge translocations in the 13-cis photocycle of the R82K mutant were investigated. Interestingly, these photocurrents were influenced by the same …
-
Intracellular pH, the Proximate Signal for Cell Volume Changes that are Mediated by the Actin Cytoskeleton
… TRC pHi and induced cell shrinkage. Removal weak acids and return to Control Ringer's solution (CR) causedTRC pHi and volume to overshoot baseline levels before fully recovering. Replacing CR with zero-sodium solution resulted in irreversible acidification of TRC pHi and induced cell …
-
Molecular structure and antibacterial function of hop resin materials
… f 13 C-NMR spectroscopy). The ability of these weak acids to ionise in solution was studied. The lack of agreement between pKa values measured using potentiometric, conductimetric, spectroscopic and solubility methods suggests that, in aqueous solution, the compounds formed covalent hydrates. …
-
Improving the solubility and dissolution of poorly soluble drugs by salt formation and the consequent effect on mechanical properties
… The drugs were chosen because they are weak acids with poor aqueous solubility and should readily form salts. The counterions used for salt formation were: butylamine, pentylamine, hexylamine, octylamine, benzylamine, cyclohexylamine, tert-butylamine, 2-amino-2-methylpropan2-ol, …
-
Study of surface modifications for improved selected metal (II-VI) semiconductor based devices.
… behaved as insoluble salts of strong bases and weak acids. Acid etchants induced a stoichiometric excess of semiconductor anion at the surface which appeared to be predominantly in the elemental or hydrogenated state. Alkaline etchants conversely induced a stoichiometric excess of semiconductor …
-
Dietary Protein Moderates Acid-Base Responses to Repeated Sprints in Exercising Horses
… strong ion difference (SID) and total weak acids (Atot) were calculated. Plasma urea-N concentrations were higher in the HP group. Plasma creatinine was not different in experiment one but was higher in the LPHF group in experiment two. Also, the LPHF group had a low body condition …
-
Investigation and development of titanium nitride solid-state potentiometric pH sensor
… stable and resist hydrolysis caused by weak acids. There are many reports on different metal nitrides electrodes in literature, of which several have been previously investigated for use as pH sensors. Here, specifically, thin films of titanium nitride (TiN) were manufactured using radio …
-
The rational design of dermatological formulations
… could impact upon the permeation of the two weak acids by altering the ionisation state of the permeants. The cosolvents, (typical formulation excipients) were water, propylene glycol ethanol, mineral oil, miglyol and Transcutol . To begin with binary combinations were tested, moving on to …
-
A mathematical model of a high sulphate wastewater, anaerobic treatment system
… organics such as ethanol or volatile fatty acids, which are directly utilized by the sulphate reducing bacteria, or complex organics such as sewage sludge which must first undergo solubilization and fermentation by a different microbial group. As an aid to the design and operation of this …
-
Salt effects and correlations with the Hammett acidity function in the decomposition of trioxane by aqueous hydrochloric acid
… been reported for many of the strong mineral acids and certain weak acids over a wide temperature range and in aqueous, nonaqueous, or mixed solvent systems. The acid-catalyzed depolymerization of trioxane is one specific reaction which has shown relationships between rate constants and …
-
The dissolution of urinary calculi
… fact that this organic matrix is resistant to weak acids and bases (30) and therefore the course of the investigation pointed to those most remarkable agents, “the enzymes”, which due to their enormous amount of surface energy are capable of producing astonishing results. The enzymes …
-
The percutaneous absorption of ionisable compounds
… model for the extraction coefficients of weak acids was derived using the partition coefficients of the ionised and unionised species, pH and pKa. This model was shown to account for the variation in overall partition of salicylic acid dependent upon pH and pKa. This model was shown to …
-
Small molecule mimics of hydrogenase enzymes: synthesis, protonation, and electrocatalysis
… undergoes protonation with weak acids, whereas, the pdt analogue requires strong acid; the difference being attributed to the presence of a pendant base in Fe2(adtNH)(CO)4(dppv)2, which is initially protonated and then relays the proton to the Fe center. Additionally, in the …
-
Funktionelle Analyse und Charakterisierung des Gpr1-Proteins in der Hefe Yarrowia lipolytica
In der Hefe Yarrowia lipolytica führen Mutationen im GPR1-Gen zu Essigsäuresensitivität. Die Deletion dieses Genes hat demgegenüber keinen Effekt auf den Phänotyp. In dieser Arbeit wurde das Gpr1-Protein näher charakterisiert. Es zeigte sich, dass GPR1-Mutantenstämme wesentlich schneller Acetat …
-
Fabrication of surface amine gradients by controlled-rate infusion for chromatographic applications
… was illustrated using mixtures of (i) four weak acids and bases and (ii) three widely-used over-the-counter drugs. Thus, the gradient stationary phase was successfully fabricated and applied as a planar chromatographic support. The next step of this research was to prepare continuous amine …
-
Incorporation of cyanide ligands into models of [FeFe]- and [NiFe]-hydrogenase
… of [(CO)(CNBArF3)2Fe(H)Ni(dxpe)]‒ with stronger acids (eg. anilinium, HCl) was found to produce H2. Furthermore, the addition of weak acids (eg. HNMe3+, pyrollidinium) were found to form a dihydrogen bond with the hydride as indicated by 1H NMR experiments. Given their hydric nature, the hydrides …