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Cellulose fiber dissolution in sodium hydroxide solution at low temperature dissolution kinetics and solubility improvement /Wang, Ying. January 2008 (has links)
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Deng, Yulin; Committee Member: Banerjee, Sujit; Committee Member: Frederick, James; Committee Member: Hsieh, Jeffery; Committee Member: Ragauskas, Arthur J.. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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AvaliaÃÃo da equivalÃncia farmacÃutica da Carbamazepina e Diazepam comercializados no Programa de FarmÃcia popular do Brasil / Assessment pharmaceutical equivalence of carbamazepine and diazepam marketed in the brazil popular pharmacy programDeysi Viviana Tenazoa Wong 20 January 2009 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A equivalÃncia farmacÃutica entre dois medicamentos relaciona-se à comprovaÃÃo de que ambos contÃm o mesmo fÃrmaco (mesma base, sal ou Ãster da mesma molÃcula terapeuticamente ativa), na mesma dosagem e forma farmacÃutica, o que pode ser avaliado por meio de testes in vitro. No Brasil, os medicamentos alopÃticos sÃo divididos em trÃs categorias quanto ao registro junto à AgÃncia Nacional de VigilÃncia SanitÃria: medicamentos novos, medicamentos similares e medicamentos genÃricos. O objetivo foi avaliar a EquivalÃncia FarmacÃutica da Carbamazepina 200 mg (CBZ) e Diazepam 10 mg (DZP) comercializados no programa FarmÃcia Popular do Brasil, visando discutir a importÃncia da qualidade dos medicamentos para a saÃde pÃblica. Utilizou-se como SubstÃncia QuÃmica de ReferÃncia (SQR) carbamazepina e diazepam, com teor declarado de 99,6 e 99,9%, respectivamente. Realizaram-se testes fÃsico-quÃmicos tais como: determinaÃÃo de peso mÃdio, desintegraÃÃo, dureza, friabilidade, teor, uniformidade de conteÃdo e perfil de dissoluÃÃo, segundo a FarmacopÃia Brasileira (F.Bras.) 4a ediÃÃo. Os resultados indicaram uma dureza menor nos comprimidos de DZP da FarmÃcia Popular. Em relaÃÃo ao Perfil de dissoluÃÃo da CBZ, a anÃlise por ANOVA indicou haver diferenÃas significativas (p<0,05) entre os perfis de dissoluÃÃo da FarmÃcia popular em relaÃÃo ao genÃrico e referÃncia nos tempos avaliados. Comparou-se o perfil de dissoluÃÃo do comprimido da FarmÃcia Popular em relaÃÃo ao medicamento referÃncia, atravÃs dos cÃlculos dos fatores de diferenÃa (f1) e semelhanÃa (f2). Obteve-se um valor de 46,29 e 35,00, respectivamente, indicando diferenÃas nos perfis avaliados. Nos comprimidos de DZP, verificou-se que os valores de percentagem de fÃrmaco dissolvido para as trÃs amostras avaliadas, foram superiores a 85% em 15 minutos de teste, e a comparaÃÃo pelo cÃlculo dos fatores de f1 e f2, nÃo pÃde ser aplicada neste caso. Evidenciou diferenÃa (p<0,05) nos primeiros 75 minutos avaliados para as trÃs amostras, o que pode nÃo ter uma significÃncia farmacÃutica. Os outros parÃmetros fÃsico-quÃmicos cumpriram com as especificaÃÃes da F. Bras. em todas as amostras de CBZ e DZP. Portanto, os comprimidos de CBZ da FarmÃcia Popular nÃo sÃo equivalentes farmacÃuticos em relaÃÃo ao medicamento referÃncia. / Two drugs are considered pharmaceutically equivalent when both contain the same drug (base, salt or ester of the same active ingredient), at the same dosage and pharmaceutical form determined in vitro. In Brazil, the allopathic drugs are classified into three cathegories when registered in the Brazilian health surveillance agency (AgÃncia Nacional de VigilÃncia SanitÃria): new, similar or generic drugs. This work aimed to determine the pharmaceutical equivalence of Carbamazepine 200 mg (CBZ) and Diazepam 10 mg (DZP) marketed in the Brazil Popular Pharmacy program, discussing the importance of drugs for public health. Carbamazepine SQR and Diazepam SQR were used as reference drugs with 99.6 and 99.9% declared content, respectively. Physicochemical studies, such as mean weight, disintegration, hardness, friability, content, content uniformity and dissolution profile were performed in accordance to Brazilian Pharmacopeia 4th edition. The results indicated a lower hardness of DZP Popular Pharmacy tablets. Despite the dissolution profile of CBZ, the ANOVA test presented significant statistical difference (p<0.05) between Popular Pharmacy tablets and generic or reference drugs in all the time point evaluated. The dissolution profile of Popular Pharmacy and reference tablets were compared through the f1 (difference) and f2 (similarity) factors. Values of 46.29 and 35.00 respectively were found suggesting a difference on the profiles evaluated. The DZP tablets, despite the sample, showed a dissolution fraction higher than 85% in 15 minutes. f1 and f2 were not possible to be calculated in these cases. The variance analysis evidenced, for all the samples, statistical difference (p< 0.05) in the first 75 minutes evaluated, what might not have pharmaceutical importance. The other physicochemical parameters were in accordance with Brazilian Pharmacopeia for all the CBZ and DZP samples. Therefore, the CBZ tables cannot be considered pharmaceutically equivalents to the reference ones.
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Zakazování politických stran-teorie a diskurz / The prohibition of the parties-theory and discourseChytil, Matěj January 2015 (has links)
Banning Political Parties - Theory and Discourse The political regime change of the Velvet revolution in 1989 brought to light many questions, that the Czech politics and law had not to answer until then. Arguments about the legitimacy of the post-revoutionary Czech communist party marked the early years of the free competition of political parties. There being no precedent in the decision-making of Czech courts, the Supreme Administrative Court had to decide many substantial questions when dealing with the case of Dělnická strana (The Workers' Party) in 2010. Some of those were elaborated by the European Court of Human Rights, other were more of a political and philosophical nature. The history and experience of pre-war Czechoslovakia and dissolution of German national-socialist parties in 1933 also influenced the debate. The Supreme Administrative Court of the Czech Republic changed in the decison of Dělnická strana the nature of Czech political discourse and brought it out of the post-communist context to the contemporary European level. Using the concept of self-defending or military democracy, that is also used by the ECHR, it created a shared framework of both Czech and European debate on the limits of political rights and freedoms of association. The concept will be contested in the future, but its...
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The Impact of the dissolution of customary marrige on children : a pastoral perspectiveLetuka, Victor Seperenkane January 2013 (has links)
The aim of the study is to investigate the impact of exclusion of children on
marriage dissolution proceedings and decisions. This investigation takes
place in Matatiele, Thotaneng at Tshita administrative area. It further
investigate to what extent are children included in the process and if they
do receive guidance in the process of the dissolution of a customary
marriage. This thesis is aiming at investigating the role of the church could
play in improving the situation of children who are caught up in the
process of the dissolution of a customary marriage and recommendations
thereof. The customary marriage, which is not registered, therefore, the
study will investigate the effect of this kind of marriage on the community
that practicing it. / Dissertation (MA Theol)--University of Pretoria, 2013. / gm2014 / Practical Theology / unrestricted
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Development of a Robust Dissolution Method for Vitamin D3Abbott, Kellie, Starnes, Emilee, Collins, Charles C 05 May 2020 (has links)
Vitamin D3 (cholecalciferol) (Vit D3) is a form of vitamin D (Vit D) that is essential for normal body function in humans. Vit D is a fat-soluble vitamin used to prevent osteoporosis in adults, prevent rickets in children, and supplement Vit D deficiencies which are seen worldwide. Physicians usually recommend 2,000 International Units (IU) Vit D3 for these deficiencies, but due to the poor aqueous solubility of Vit D3, this dose can be insufficient for patients. It would be more beneficial to recommend 5,000 IU. In 1994, the Dietary Supplement Health and Education Act was passed defining vitamins as “dietary supplements” and no longer required FDA registration prior to marketing. Dissolution results are expressed as the percent of the content released into solution, with a target of 85 to 125%. There is not an effective dissolution test existing for Vit D3 product evaluation, so an optimized dissolution test for Vit D3 was developed and used to evaluate non-prescription Vit D3 products. The current FDA guideline for Vit D3 dissolution is USP Apparatus II with 500 mL of 0.3% sodium dodecyl sulfate (SDS) in water. Since Vit D3 is not very water soluble, a surfactant is required for it to go into solution. The research was started with a larger volume (1 L) and with commonly used pharmaceutical grade surfactants: Triton X-100, Tween 80, Span 20, and sodium lauryl sulfate (SLS). SDS was eliminated due to interference with the HPLC analysis. Using two Vit D3 test products, which previous research found to have consistent drug content, each of these surfactants were tested at 0.8%. After evaluating the HPLC results, Triton and Tween were eliminated due to too much interference with the analysis process. The interference consisted of a large initial solvent front peak, elevated baseline, overlap with the drug peak, and required significant decrease in the mobile phase flow rate. Changing the mobile phase to 50/50 methanol/1-propanol solved the flow rate issue and peak separation overlap, but not the large solvent peak or elevated baseline. Dissolution testing continued using SLS and Span using 0.6%. Dissolution of the two test products, designated A and B, with 2 representing 2000 IU and 5 being 5000 IU, yielded higher values using SLS (A2 75.5%; A5 152.8%; B2 30.9%; B5 36.6%) compared to Span (A2 15%; A5 136%; B2 20.3%; B5 63%). Additional work continued to determine the best concentration of SLS. Better dissolution results were obtained using 1.2% (A2 88.1%; A5 156.7%) when compared to 0.3% (A2 87.4%; A5 153.2%), 0.6% (A2 70.7%; A5 132.2%), and 0.9% (A2 79.7%; A5 150.5%). Use of 1.5% did not yield a significant improvement (A2 84% vs 86.8%; A5 146.4% vs 144.6%), so 1.2% was chosen as this would minimize the amount of surfactant in the samples. The final dissolution method was created using a USP Apparatus II in 1000 mL containing 1.2% SLS in water. Based upon these characteristics, SLS 1.2% gave a good balance of minimizing surfactant concentration and analytical interference while maximizing Vit D3 dissolution.
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Sorption and weathering properties of naturally occurring chloritesGustafsson, Åsa January 2004 (has links)
Chlorite is a ferrous silicate mineral occurring as afracture filling mineral in the Swedish granite bedrock thatsurrounds the area of the candidate Swedish geologicalrepositories for nuclear waste. To investigate the importance of chlorites as a naturalbarrier for radionuclide migration sorption of Ni(II) onto anatural chlorite was chosen as the studied system. The sorptionbehaviour was studied using batch technique under differentexperimental conditions by varying the concentration ofbackground electrolyte, pH and initial nickel concentration.Our experiments showed that sorption is dependent of pH; belowpH 4 no sorption occurs and in the pH range 7-11 the sorptionmaxima was found. The sorption shows no dependence of ionicstrength in our experiments and together with pH dependency weconclude that the sorption of nickel to chlorite is mostlyoccurring through surface complexation. The distributioncoefficient, Kd, was determined for our results and in the range formaximal sorption the Kdis approximately 103cm3/g. Our experimental data were described using a diffuse doublelayer model, including strong and weak surface sites, in thesoftware PHREECQ and the results obtained from PHREEQC werealso used for a fit of the data in the software FITEQL. Thesurface complexes that dominate the sorption of nickel tochlorite from our model are Chl_ONi+(weak) and for pH above 9 Chl_ONi(OH)-(weak). Flow-through technique was used in ourinvestigations regarding the dissolution rate of a naturalchlorite and the experimental results show that the dissolutionrate of chlorite is strongly pH dependent and at pH 2 thehighest dissolution rate (RSi) could be determined to 7• 10-11mol/(m2s) based on silica data. Keywords:chlorite, nickel, sorption, surfacecomplexation, dissolution rate.
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Reclamation and Reprocessing of Thermotropic Liquid Crystalline Polymer from Composites of Polypropylene Reinforced with Liquid Crystalline PolymerCollier, Monty C. 28 July 1998 (has links)
The composites industry can be positively influenced by composite materials that are processed faster, are lighter in weight, are higher in stiffness and strength, and that are more recyclable. There has been considerable interest in the use of thermotropic liquid crystalline polymers (TLCPs) to reinforce thermoplastic materials. In a novel process developed by Baird and coworkers, wholly thermoplastic composites are produced via a patented, dual extrusion process. This unique process yields a fiber which consists of numerous continuous fibrils of the liquid crystalline polymer encased in a thermoplastic matrix. These fibers have been used to form random mats and woven pre-forms, which have then been compression molded to form composite parts. Because of the high cost associated with these thermotropic liquid crystalline polymers and the desire to generate recyclable composites, a process was developed in this research to separate the liquid crystalline component from polypropylene (PP) composites.
The overall objectives of this work were to develop a process to reclaim the liquid crystalline component of these thermoplastic composites, to determine the effect the process had on the properties of the reclaimed liquid crystalline polymer, and finally to determine whether or not the reclaimed liquid crystalline polymer could be used again to generate a reinforcing component. An ancillary objective was to see if the polypropylene could also be reclaimed, and if it had further use as a polymeric resin.
In the present work, a novel process was developed that allows the liquid crystalline component to be reclaimed for further use in the composite material or in other applications that require thermotropic liquid crystalline polymers. The polypropylene component, which has undergone molecular weight reduction, can also be reclaimed by this process. This process consisted of using an organic peroxide and reactive extrusion to selectively degrade only the polypropylene, and not the thermotropic liquid crystalline polymer. The degraded polypropylene was selectively dissolved away from the liquid crystalline polymer by stirring the extruded melt in boiling mineral oil. The remaining solids, of thermotropic liquid crystalline polymer, were collected via centrifugation, cleaned of the mineral oil by boiling in kerosene, and then dried in a convection oven. The purity of the reclaimed thermotropic liquid crystalline polymer was determined by density measurements, while the physical properties of the reclaimed material were determined by rheological tests. The mechanical properties were determined via Instron testing of injection molded plaques made from mixtures of reclaimed material and pure thermotropic liquid crystalline polymer.
From this work, it was found that over 70 wt% of the thermotropic liquid crystalline polymer, DuPont HX8000, could be successfully separated from the polypropylene to a degree of 96.0%. From Instron testing, it was found that up to 40 wt% of the reclaimed HX8000 could be blended with the pure HX8000, with no loss in mechanical properties. Furthermore, it was seen that up to 83 % of the HX8000 component (40 wt%) of PP 6523 (60 wt%) composites could be replaced with reclaimed HX8000 without seeing any losses in mechanical properties. It was also found that the degraded polypropylene could be successfully separated, via centrifugation at a temperature of 253 K, and could be potentially used as resin for non-wovens. The projected material cost of the reclaimed HX8000, based on the ability to purchase and to process in bulk, was determined to be 90 % less than the virgin HX8000. / Master of Science
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Mechanism of Anodic Dissolution of Iron and Steel in CO2 EnvironmentsBagheri Hariri, Mohiedin 05 June 2023 (has links)
No description available.
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Multicomponent Ligand Interactions with Colloidal Gold and Silver Nanoparticles in WaterSiriwardana, Wumudu Dilhani 11 August 2017 (has links)
Multicomponent ligand interactions are involved in essentially all nanoparticle (NP) applications. However, the ligand conformation and ligand binding mechanisms on NPs are highly controversial. The research reported here is focused on deepening the fundamental understanding of multicomponent ligand interactions with gold and silver nanoparticles (AuNPs and AgNPs) in water. We demonstrated that AuNPs passivated by saturated layer of poly(ethylene glycol) (PEG-SH) have large fractions of AuNP surface area available for ligand adsorption and exchange. The fraction of AuNP surface area passivated by PEG-SH with molecular weights of 2000, 5000, and 30000 g/mol was calculated to be ~ 25%, ~20%, and ~9% using 2-mercaptobenzimidazole and adenine as model ligands. The effect of both reduced and oxidized protein cysteine residues on protein interactions with AgNPs was investigated. The model proteins included wild-type and mutated GB3 variants with 0, 1, or 2 reduced cysteine residues. Bovine serum albumin containing 34 oxidized (disulfide-linked) and 1 reduced cysteine residues was also included. Protein cysteine content that were found to have no detectable effect on kinetics of protein/AgNP binding. However, only proteins that contain reduced cysteine induced significant AgNP dissolution. We further demonstrated that organothiols can induce both AgNP disintegration and formation under ambient conditions by simply mixing organothiols with AgNPs or AgNO3, respectively. Surface plasmon- and fluorescence-active AgNPs formed by changing the concentration ratio between Ag+ and organothiol. Organothiols also induced AuNP formation by mixing HAuCl4 with organothiols, but no AuNP disintegration occured. Finally, we proposed that multicomponent ligand binding to AuNPs can be highly dependent on the sequence of ligand mixing with AuNPs. Quantitative studies revealed that competitive adenine and glutathione adsorption onto both as-synthesized and PEG-SH functionalized AuNPs is predominantly a kinetically controlled process. Besides providing new insights on multicomponent ligand interactions with colloidal AuNPs and AgNPs, this study opens a new avenue for fabrication of novel nanomaterials in biological/biomedical applications.
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Prescribed ego-death: the therapeutic effects found in the psychedelic-Induced absence of selfWellander, Klara January 2022 (has links)
Depression and anxiety are two of the world’s most common neuropsychiatric conditions. There has been some success in treating depression and anxiety by using classic psychedelic drugs to cause positive changes in psychological well-being. Depression and anxiety are often correlated to self-rumination and a heightened sense of self, making sufferers unable to withdraw from repetitive negative self-referenced thought patterns. Some researchers hypothesize that the therapeutic effects of psychedelics come from their acute subjective effects, specifically ego-dissolution. This systematic review aimed to investigate what clinical studies can support this hypothesis. By reviewing five studies that examined this correlation, this review found that the majority of the studies could present a moderate correlation. This suggests a negative correlation between the degree of ego-dissolution and the therapeutic improvements in disorders with a heightened sense of self.
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