The career indecision profile : measurement equivalence in two international samples

This study tested for the measurement equivalence of a four-factor measure of career indecision (Career Indecision Profile-65 [CIP-65]) between a U.S. sample and two international samples; one composed of French-speaking young adults from France and Switzerland and the other of Italian ado- lescents. Previous research had supported the four-factor structure of the CIP-65 in both the United States and Iceland but also showed that items on two of the four scales may be interpreted differently by young adults growing up in these two countries. This study extends previous research by testing whether the four CIP-65 factors are measured equivalently in two additional international samples. Results largely supported the configural and metric invariance of the CIP-65 in the United States and international samples, but several scales showed a lack of scalar invariance. Some explanations are offered for these findings along with suggestions for future research and implications for practice.

A novel cyclosporin a aqueous formulation for dry eye treatment: in vitro and in vivo evaluation.

PURPOSE: The aim of the present study was the in vitro and in vivo evaluation of a novel aqueous formulation based on polymeric micelles for the topical delivery of cyclosporine A for dry eye treatment. METHODS: In vitro experiments were carried out on primary rabbit corneal cells, which were characterized by immunocytochemistry using fluorescein-labeled lectin I/isolectin B4 for the endothelial cells and mouse monoclonal antibody to cytokeratin 3+12 for the epithelial ones. Living cells were incubated for 1 hour or 24 hours with a fluorescently labeled micelle formulation and analyzed by fluorescence microscopy. In vivo evaluations were done by Schirmer test, osmolarity measurement, CyA kinetics in tears, and CyA ocular distribution after topical instillation. A 0.05% CyA micelle formulation was compared to a marketed emulsion (Restasis). RESULTS: The in vitro experiments showed the internalization of micelles in the living cells. The Schirmer test and osmolarity measurements demonstrated that micelles did not alter the ocular surface properties. The evaluation of the tear fluid gave similar CyA kinetics values: AUC = 2339 ± 1032 min*μg/mL and 2321 ± 881.63; Cmax = 478 ± 111 μg/mL and 451 ± 74; half-life = 36 ± 9 min and 28 ± 9 for the micelle formulation and Restasis, respectively. The ocular distribution investigation revealed that the novel formulation delivered 1540 ± 400 ng CyA/g tissue to the cornea. CONCLUSIONS: The micelle formulation delivered active CyA into the cornea without evident negative influence on the ocular surface properties. This formulation could be applied for immune-related ocular surface diseases.

Biotransformations of water insoluble substrates in aqueous, two-phase and encapsulated systems /

The biotransformation of water insoluble substrates by mammalian and bacterial cells has been problematic, since these whole cell reactions are primarily performed in an aqueous environment The implementation of a twophase or encapsulated system has the advantages of providing a low water system along with the physiological environment the cells require to sustain themselves. Encapsulation of mammalian cells by formation of polyamide capsules via interfacial polymerization illustrated that the cells could not survive this type of encapsulation process. Biotransformation of the steroid spironolactone [3] by human kidney carcinoma cells was performed in a substrate-encapsulated system, yielding canrenone [4] in 70% yield. Encapsulation of nitrile-metabolizing Rhodococcus rhodochrous cells using a polyamide membrane yielded leaky capsules, but biotransformation of 2-(4- chlorophenyl)-3-methylbutyronitrile (CPIN) [6] in a free cell system yielded CPIN amide [7] in 40% yield and 94% ee. A two-phase biotransformation of CPIN consisting of a 5:1 ratio of tris buffer, pH 7.2 to octane respectively, gave CPIN acid [8] in 30% yield and 97% ee. It was concluded that Rhodococcus rhodochrous ATCC 17895 contained a nonselective nitrile hydratase and a highly selective amidase enzyme.

Continuous hydride generation in the presence of L- cysteine for the determination of arsenic, bismuth, antimony and tin in steels by inductively coupled plasma atomic emission spectrometry

Arsenic, bismuth, germanium, antimony and tin were simultaneously determined by continuous hydride generation and inductively coupled plasma-atomic emission spectrometry . I Hydrides were introduced into four different types of gas-liquid separators. Two of the gas-liquid separators were available in-house. A third was developed for this project and a fourth was based on a design used by CET AC. The best signal intensity was achieved by the type II frit-based gas-liquid separator, but the modified Cetac design gave promise for the future, due to low relative standard deviation. A method was developed for the determination of arsenic, bismuth, antimony and tin in low-alloy steels. Four standard reference materials from NIST were dissolved in 10 mL aqua regia without heat. Good agreement was obtained between experimental values and certified values for arsenic, bismuth, antimony and tin. The method was developed to provide the analyst with the opportunity to determine the analytes by using simple aqueous standards to prepare calibration lines. Within the limits of the samples analyzed, the method developed is independent of matrix.

Effects of sample solvent composition and injection volume on chromatographic peak profiles of methyl w- benzimidazolecarbamate and 3-butyl1-2,4-dioxo[1,2-a]-s- triazinobenzimidazole in RP-HPLC

The effects of sample solvent composition and the injection volume, on the chromatographic peak profiles of two carbamate derivatives, methyl 2-benzimidazolecarbamate (MBC) and 3-butyl-2,4-dioxo[1,2-a]-s-triazinobenzimidazole (STB), were studied using reverse phase high performance liquid chromatograph. The study examined the effects of acetonitrile percentage in the sample solvent from 5 to 50%, effects of methanol percentage from 5 to 50%, effects of pH increase from 4.42 to 9.10, and effect of increasing buffer concentration from ° to 0.12M. The effects were studied at constant and increasing injection mass and at four injection volumes of 10, 50, 100 and 200 uL. The study demonstrated that the amount and the type of the organic solvents, the pH, and the buffer strength of the sample solution can have a pronounced effect on the peak heights, peak widths, and retention times of compounds analysed. MBC, which is capable of intramolecular hydrogen bonding and has no tendency to ionize, showed a predictable increase .in band broadening and a decrease in retention times at higher eluting strengths of the sample solvent. STB, which has a tendency to ionize or to strongly interact with the sample solvent, was influenced in various ways by the changes in ths sample solvent composition. The sample solvent effects became more pronounced as the injection volume increased and as the percentage of organic solvent in the sample solution became greater. The peak height increases for STB at increasing buffer concentrations became much more pronounced at higher analyte concentrations. It was shown that the widely accepted procedure of dissolving samples in the mobile phase does not yield the most efficient chromatograms. For that reason samples should be dissolved in the solutions with higher aqueous content than that of the mobile phase whenever possible. The results strongly recommend that all the samples and standards, regardless whether the standards are external or internal, be analysed at a constant sample composition and a constant injection volume.

Investigation into the determination of arsenic by direct current plasma atomic emission spectrometer

Improvements have been made on the currently available hydride generator system manufactured by SpectraMetrics Incorporated, because the system was found to be unsatisfactory with respect to the following: 1. the drying agent, anhydrous calcium chloride, 2. the special sample tube, 3. the direction of argon flow through the Buchner funnel when it came to dealing with real sample, that is, with reference only to aqueous extracts of soil samples. Changes that were made on the system included the replacement of anhydrous calcium chloride with anhydrous calcium sulphate and the replacement of the special sample tube with a modified one made from silica. Re-directing the flow of argon through the top of the Buchner funnel appeared to make the system compatible with aqueous extracts of soil samples. The interferences from 1000 ~g/mL of nickel(II) , cobalt(II), iron(III), copper(II) have been eliminated with the aid of 1.4 M hydrochloric acid and 1% (weight/volume) L-cystine. Greater than 90% recovery of 0.3 ~g/mL arsenic signal was achieved in each case. Furthermore, 103% of arsenic signal was accomplished in the presence of 1000 ~g/mL cadmium with 5 M Hel. tVhen each of the interferents was present in solution at 1000 ppm, a recovery of 85% was achieved by using 5 M hydrochloric acid and 3% (weight/volume) L-cystine. Without L-cystine and when 1.4 M hydrochloric acid was used, the recoveries were 0% (Ni), 0% (Co), 88% (Fe), 15% (Cu), 18% (Cd). Similarly, a solution containing 1000 ppm of each interferent gave a zero percent recovery of arsenic. The reduction of trivalent and pentavalent arsenic at a pH less than one has also been investigated and shown to be quantitative if peak areas are measured. The reproducibility determination of a 0.3 Vg/mL standard arsenic solution by hydride generation shows a relative standard deviation of 3.4%. The detection limits with and without Porapak Q have been found to be 0.6 ng/mL and 1.0 ng/mL, respectively.

Molecular mechanics calculations on some phosphine oxide metal complexes in aqueous and organic solvents

Molecular mechanics calculations were done on tetrahedral phosphine oxide zinc complexes in simulated water, benzene and hexane phases using the DREIDING II force field in the BIOGRAF molecular modeling program. The SUN workstation computer (SUN_ 4c, with SPARK station 1 processor) was used for the calculations. Experimental structural information used in the parameterization was obtained from the September 1989 version of the Cambridge Structural Database. 2 Steric and solvation energies were calculated for complexes of the type ZnCl2 (RlO)2' The calculations were done with and without inclusion of electrostatic interactions. More reliable simulation results were obtained without inclusion of charges. In the simulated gas phase, the steric energies increase regularly with number of carbons in the alkyl group, whereas they go through a maximum when solvent shells are included in the calculation. Simulated distribution ratios vary with chain length and type of chain branching and the complexes are found to be more favourable for extraction by benzene than by hexane, in accord with experimental data. Also, in line with what would be expected for a favorable extraction, calculations without electrostatics predict that the complexes are better solvated by the organic solvents than by water.

Study of heat capacity measurement methods for small samples

Methods of measuring specific heats of small samples were studied. Three automated methods were explored, two of which have shown promising results. The adiabatic continuous heating method, has provided smooth well behaved data but further work is presently underway to improve on the results obtained so far . The decay method has been success fully implemented demonstrating reasonable agreement with accepted data for a copper test sample.

The application of gas liquid chromatography to the simultaneous analysis of sugars and sugar phosphates in biological samples /|nby David J. LeBlanc. -- 260 St. Catharines [Ont. : s. n.],

A study was undertaken' to determine the applicability of gas liquid chromatography to the simultaneous analysis of sugars and sugar phosphates from biological samples. A new method of silylation involving dimethylsulfoxide, hexamethyldisilazane, trimethylchlorosilane and cyclohexane (1:0.2:0.1:1) which rapidly silylated sugars and sugar phosphates was developed. Subsequent chromatography on a 5% SE-52 column gave good resolution of the sugar and sugar phosphate samples. Sugar phosphates decomposed during chromatography and were lost at the 7 x 10-3 ~mole level. Acidic ethanol extraction of yeast samples revealed background contamination from the yeast sample, the culture medium and the silylation reagents which would further limit the level of detection obtainable with the glc for sugars in biological samples to the 3 x 10-4 ~mole level.

An investigation of the psychopathy construct and its (novel) correlates in non-clinical samples

A substantial research literature exists regarding the psychopathy construct in forensic populations, but more recently, the construct has been extended to non-clinical populations. The purpose of the present dissertation was to investigate the content and the correlates of the psychopathy construct, with a particular focus on addressing gaps and controversies in the literature. In Study 1, the role of low anxiety in psychopathy was investigated, as some authors have proposed that low anxiety is integral to the psychopathy construct. Participants (n = 346) responded to two self-report psychopathy scales, the SRP-III and the PPI-R, as well as measures of temperament, personality, and antisociality. Of particular interest was the PPI-R Stress Immunity sub scale, which represents low anxiety content. I t was found that Stress Immunity was not correlated with SRP-III psychopathy, nor did it share common personality or temperament correlates or contribute to the prediction of anti sociality. From Study 1, it was concluded that it was unlikely that low anxiety is a central feature of the psychopathy construct. In Study 2, the relationship between SRP-III psychopathy and Ability Emotional Intelligence (Le., Emotional Intelligence measured as an ability, rather than as a self-report personality trait-like characteristic) was investigated, to determine whether psychopathy is be s t seen as a syndrome characterized by emotional deficits or by the ability to skillfully manipulate and prey upon the others' emotions. A negative correlation between the two constructs was found, suggesting that psychopathy is best characterized by deficits in perceiving, facilitating, managing, and understanding emotions. In Study 3, sex differences in the sexual behavior (i.e., promiscuity, age of first sexual behaviors, extradyadic sexual relations) and appearance-related esteem (i.e., body shame,appearance anxiety, self-esteem) correlates of SRP-III psychopathy were investigated. The sexual behavior correlates of psychopathy were quite similar for men and women, but the esteem correlates were very different, such that high psychopathy in men was related to high esteem, whereas high psychopathy in women was generally related to low esteem. This sex difference was difficult to interpret in that it was not mediated by sexual behavior, suggesting that further exploration of this topic is warranted. Together, these three studies contribute to our understanding of non-clinical psychopathy, indicating that low anxiety is likely not part of the construct, that psychopathy is related to low levels of ability in Emotional Intelligence, and that psychopathy is an important predictor of behavior, ability, and beliefs and feelings about the self

Influence of functional groups of activated carbon in the anchoring of iron particles by forced hydrolysis and its use to remove hexavalent chromiun from aqueous solutions.

Tesis (Master of Science with orientation in Sustainable Processes) UANL, 2014.

Modification d'acides biliaires à l'aide de polymères pour en moduler les propriétés d'agrégation

Les polymères amphiphiles sont largement utilisés pour les applications biomédicales et pharmaceutiques. Afin d’améliorer les chances de biocompatibilité des nouveaux polymères que nous voulons développer, nous avons utilisé des composés naturels, les acides biliaires, comme produits de départ dans la synthèse de ces polymères. De nouveaux polymères anioniques amphiphiles dérivés de l’acide cholique ont été préparés par polymérisation radicalaire par transfert d’atomes. Par un contrôle rigoureux des conditions de polymérisation, des bras de poly(acide acrylique) de différentes longueurs ont été greffés sur le squelette de l’acide cholique. L’architecture moléculaire des polymères a été étudiée par spectroscopie 1H RMN et par spectrométrie de masse. Ces polymères en étoile formés par l’acide biliaire modifié sont capables de s’agréger dans l’eau même si les groupements hydroxyles ont été remplacés par des segments plus volumineux. Il a été observé que les liaisons ester entre le polymère et le cœur d’acide cholique sont sensibles à l’hydrolyse en solution aqueuse. Pour remédier au problème de stabilité en solution aqueuse et pour avoir, en même temps, des bras hydrophiles non ioniques et biocompatibles, de l’oxyde d’éthylène a été polymérisé sur l’acide cholique par polymérisation anionique. Les liaisons éther formées entre le polymère et les groupements hydroxyles de l’acide biliaire sont plus stables que les liaisons ester sur le polymère de poly(acide acrylique). Les conditions de réaction de la polymérisation anionique ont été optimisées et ont donné des polymères aux architectures et aux masses molaires contrôlées. Les nouveaux polymères forment des agrégats sphériques tel qu’observé par microscopie électronique à transmission avec des échantillons préparés par la méthode de fracture à froid. Leur morphologie est différente de celle des agrégats cylindriques formés par les acides biliaires. Avec la méthode optimisée pour la polymérisation anionique, l’éther d’allyle et glycidyle a été polymérisé sur un dérivé d’acide cholique, suivi par une thiolation des liaisons doubles pour introduire l’amine ou l’acide sur la chaîne polymère. Cette addition radicalaire est efficace à plus de 90%. Les polymères qui en résultent sont solubles dans l’eau et s’agrègent à une certaine concentration critique. Il est particulièrement intéressant d’observer la thermosensibilité des polymères ayant des groupements amine, laquelle peut être modulée en acétylant partiellement les amines, donnant des points nuages entre 15 et 48°C.

Étude des propriétés de transport dans les hydrogels de curdlan

Les hydrogels de polysaccharide sont des biomatériaux utilisés comme matrices à libération contrôlée de médicaments et comme structures modèles pour l’étude de nombreux systèmes biologiques dont les biofilms bactériens et les mucus. Dans tous les cas, le transport de médicaments ou de nutriments à l’intérieur d’une matrice d’hydrogel joue un rôle de premier plan. Ainsi, l’étude des propriétés de transport dans les hydrogels s’avère un enjeu très important au niveau de plusieurs applications. Dans cet ouvrage, le curdlan, un polysaccharide neutre d’origine bactérienne et formé d’unités répétitives β-D-(1→3) glucose, est utilisé comme hydrogel modèle. Le curdlan a la propriété de former des thermogels de différentes conformations selon la température à laquelle une suspension aqueuse est incubée. La caractérisation in situ de la formation des hydrogels de curdlan thermoréversibles et thermo-irréversibles a tout d’abord été réalisée par spectroscopie infrarouge à transformée de Fourier (FT-IR) en mode réflexion totale atténuée à température variable. Les résultats ont permis d’optimiser les conditions de gélation, menant ainsi à la formation reproductible des hydrogels. Les caractérisations structurales des hydrogels hydratés, réalisées par imagerie FT-IR, par microscopie électronique à balayage en mode environnemental (eSEM) et par microscopie à force atomique (AFM), ont permis de visualiser les différentes morphologies susceptibles d’influencer la diffusion d’analytes dans les gels. Nos résultats montrent que les deux types d’hydrogels de curdlan ont des architectures distinctes à l’échelle microscopique. La combinaison de la spectroscopie de résonance magnétique nucléaire (RMN) à gradients pulsés et de l’imagerie RMN a permis d’étudier l’autodiffusion et la diffusion mutuelle sur un même système dans des conditions expérimentales similaires. Nous avons observé que la diffusion des molécules dans les gels est ralentie par rapport à celle mesurée en solution aqueuse. Les mesures d’autodiffusion, effectuées sur une série d’analytes de diverses tailles dans les deux types d’hydrogels de curdlan, montrent que le coefficient d’autodiffusion relatif décroit en fonction de la taille de l’analyte. De plus, nos résultats suggèrent que l’équivalence entre les coefficients d’autodiffusion et de diffusion mutuelle dans les hydrogels de curdlan thermo-irréversibles est principalement due au fait que l’environnement sondé par les analytes durant une expérience d’autodiffusion est représentatif de celui exploré durant une expérience de diffusion mutuelle. Dans de telles conditions, nos résultats montrent que la RMN à gradients pulsés peut s’avérer une approche très avantageuse afin de caractériser des systèmes à libération contrôlée de médicaments. D’autres expériences de diffusion mutuelle, menées sur une macromolécule de dextran, montrent un coefficient de diffusion mutuelle inférieur au coefficient d’autodiffusion sur un même gel de curdlan. L’écart mesuré entre les deux modes de transport est attribué au volume différent de l’environnement sondé durant les deux mesures. Les coefficients d’autodiffusion et de diffusion mutuelle similaires, mesurés dans les deux types de gels de curdlan pour les différents analytes étudiés, suggèrent une influence limitée de l’architecture microscopique de ces gels sur leurs propriétés de transport. Il est conclu que les interactions affectant la diffusion des analytes étudiés dans les hydrogels de curdlan se situent à l’échelle moléculaire.

Développement de peptidomimétiques antagonistes du récepteur de l’interleukine-1β

Dans ce mémoire, je présente mes études sur la synthèse, la caractérisation et l’évaluation biologique de différentes séries d’analogues du D-heptapeptide appelé 101.10, un modulateur négatif allostérique du récepteur de l’interleukine-1β (IL-1β). Sachant que les peptides ont généralement de faibles propriétés pharmacologiques, le but de ce projet portait sur l’examen des structures nécessaires à la bioactivité, la conformation tridimensionnelle de ces derniers afin d’améliorer la droguabilité du peptide parent. Les stratégies d’optimisation du 101.10 utilisées furent : la coupure N- et C-terminale; la substitution par la proline, α-amino-γ-lactame (Agl), β-amino-γ-lactame (Bgl) et α-amino-β-hydroxy-γ-lactame (Hgl); et la rigidification du squelette à l’aide d’un bicycle, l’indolozidin-2-one (I2aa). Afin de clarifier certaines relations de structure-activité, quelques modifications furent apportées au peptide, incluant l’échange de la thréonine pour la valine, la permutation de la stéréochimie de certains résidus clés ainsi que le remplacement de certaines chaînes latérales par un méthyle. Pour pallier aux difficultés de reproductibilité des résultats avec des échantillons provenant de différentes sources, des études sur l’identité du contre-anion et la pureté du peptide furent conduites. Afin d’évaluer l’effet des modifications sur la conformation aqueuse et l’activité biologique du peptide, des analyses de dichroïsme circulaire et des tests in vitro mesurant l’inhibition de certains effets de l’IL-1β furent effectués. Ces essais cellulaires comportaient l’inhibition de la prolifération de cellules immunes et de l’activation des voies de signalisation inflammatoires du facteur nucléaire κB (NF-κB) et de la protéine kinase activée par mitogène (MAPK), toutes deux stimulées par l’IL-1β. La compilation de ces données a permis de déceler certaines tendances entre la structure, la conformation et l’activité anti-IL-1β des peptidomimétiques.