Дисертації з теми "Polymorphic transformations"
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Strege, Christine. "On (pseudo- ) polymorphic phase transformations." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974120006.
Повний текст джерелаSheridan, Andrew Keith. "Kinetics and temperature- and pressure-induced polymorphic phase transformations in molecular crystals." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322597.
Повний текст джерелаSoltani, Morteza. "Strength, fracture morphology, and polymorphic phase transformations in phosphate-bonded high-alumina refractory compositions." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19060.
Повний текст джерелаDharmayat, Spoorthi. "Polymorphic transformation of pharmaceutical compounds." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507688.
Повний текст джерелаShimobayashi, Norimasa. "High Temperature Transmission Electron Microscopy of the Polymorphic Phase Transformation in Ca-poor Pyroxenes." 京都大学 (Kyoto University), 1989. http://hdl.handle.net/2433/86417.
Повний текст джерелаSouza, Kellen Christina Dutra de. "Preparação e caracterização de estruturas polimórficas da tolbutamida e nifedipina." Universidade Federal Fluminense, 2005. http://www.bdtd.ndc.uff.br/tde_busca/arquivo.php?codArquivo=1334.
Повний текст джерелаNeste estudo foram preparados polimorfos do fármaco tolbutamida, um hipoglicemiante oral usado no tratamento dos Diabetes Mellitus tipo II. Foram também preparados polimorfos da nifedipina, fármaco usado no tratamento das desordens cardiovasculares, como angina pectoris e hipertensão. A preparação dos polimorfos foi mediada por solvente, ou seja, foi em função do solvente usado nas etapas de cristalização e de precipitação das espécies. Um método de resfriamento rápido por nitrogênio líquido também foi utilizado. Técnicas analíticas como a espectrofotometria de infravermelho, a calorimetria diferencial de varredura, a difratometria de raio-X e a microscopia eletrônica de varredura foram úteis para a caracterização dos produtos obtidos experimentalmente. Os resultados comprovaram que dois polimorfos da tolbutamida foram preparados, ambos com estrutura cristalina. No caso da nifedipina, dois polimorfos foram preparados e a caracterização mostrou que um destes foi obtido num estado amorfo enquanto o outro estava sob forma cristalina. A instabilidade da nifedipina no estado amorfo foi monitorada pela técnica de calorimetria diferencial de varredura que, através de diferentes curvas, mostrou uma transformação rápida para uma estrutura cristalina. Esta mesma técnica aliada à termogravimetria confirmou a obtenção de um terceiro produto da nifedipina, de estrutura cristalina, que foi considerado um pseudopolimorfo por ser uma espécie solvatada. Ao final do procedimento experimental e da avaliação dos resultados foi sugerido um esquema, passo a passo, para obtenção e caracterização de polimorfos de uma substância
In this study the polymorphs of tolbutamide, an oral hypoglicemiant used on Diabetes Mellitus type II treatment, and of nifedipine, a drug used in the cardiovascular disorders treatment, were prepared. All crystalline forms were obtained by crystallization from different solvents. Tolbutamide was isolated only in crystalline forms and nifedipine in two crystalline forms and in the amorphous form prepared by melting and subsequent cooling. The polymorphs from each drug were characterized by powder x-ray diffraction (PDRX), infrared spectroscopy (IR), Raman spectroscopy (FT-RAMAN), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results proved that two different crystalline forms of tolbutamide were obtained and two crystalline form to nifedipine, one of them as a pseudo-polymorph. The characterization confirmed that melting and quickly cooling procedure prepared amorphous nifedipine. Differential scanning calorimetry technique generated curves whose data proved that the amorphous nifedipine is a very unstable form. Thermogravimetry confirmed a pseudo-polymorphs preparation of nifedipine. In spite of the modification observed on the profile of X-ray diffraction, because of the solvent present, was possible to prove that this solvated form have an crystalline structure. A methodology was proposed step by step to prepare and characterize polymorphs of a substance
Chan, Fung Choy. "Powder X-ray diffraction studies of structural and kinetic aspects of polymorphism." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327050.
Повний текст джерелаSpektor, Kristina. "Extreme water catalyzed transformations of SiO2, TiO2 and LiAlSiO4." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-124010.
Повний текст джерелаAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Ray, Kamal Kanti. "Characterization of phase state, morphological, mechanical and electrical properties of nano- and macro-dimensional materials." Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/7017.
Повний текст джерелаSchweinefuß, Maria E., Sergej Springer, Igor A. Baburin, Todor Hikov, Klaus Huber, Stefano Leoni, and Michael Wiebcke. "Zeolitic imidazolate framework-71 nanocrystals and a novel SOD-type polymorph: solution mediated phase transformations, phase selection via coordination modulation and a density functional theory derived energy landscape." Royal Society of Chemistry, 2014. https://tud.qucosa.de/id/qucosa%3A36102.
Повний текст джерелаSvärd, Michael. "Structural, Kinetic and Thermodynamic Aspects of the Crystal Polymorphism of Substituted Monocyclic Aromatic Compounds." Doctoral thesis, KTH, Teknisk strömningslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33836.
Повний текст джерелаQC 20110527
Artigas, Alava Miguel José. "Contribution à l'étude du polymorphisme des phases MM'X (M,M' = métaux de transition, X=P, As)." Grenoble 1, 1992. http://www.theses.fr/1992GRE10133.
Повний текст джерелаFlores, Roxana Lili Roque. "Caracterização do estado sólido de ganciclovir." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-16112017-173605/.
Повний текст джерелаThis presented work aims to study the solid state of ganciclovir (GCV) and its different polymorphic forms. GCV is an antiviral drug useful in the treatment of cytomegalovirus (CMV) infections. Although it is a widely-used drug, few studies have been conducted on its solid state. Currently, GCV is known to have four crystalline forms, two anhydrous (Form I and II) and two hydrates (III and IV). In this investigation, we report a successful preparation of GCV Form I and its crystallographic structure, which was found during the crystallization of the drug, in which nine crystallization tests (GCV-1, GCV-A, GCV-B, GCV- D, GCV-E, GCV-F, GCV-G and GCV-H) were performed and the resulting materials were characterized by X-ray diffractometry (XRD), thermal analysis (DTA/TG) and Hot Stage Microscopy. Of all the crystallizations performed, four solid forms were obtained, denoted as Form I (GCV-1, GCV-B and GCV- H), Form III (GCV-C, GCV-D, GCV-F and GCV-G), Form IV (GCV-A) and Form V (GCV-E). The latter is being described for the first time in the literature and indicates the presence of another hydrated form of GCV. Forms I, III and IV corresponded to the anhydrous form and the two hydrated forms of the drug, respectively. In addition, it was evident by both the slurry conversion and the thermal analysis methods that the GCV-1 crystallized (Form I) was indeed the most stable amongst the materials obtained. This gave rise to GCV Form I monocrystal, anhydrous crystalline structure of the drug. The compound was characterized by monocrystal X-ray crystallography. The structural analysis showed that Form I of the drug crystallized in the monoclinic system space group P21/c is composed of four molecules of GCV in its asymmetric unit. Each molecule is linked intermolecularly by hydrogen bonds, which give rise to the formation of infinite chains arranged in a way that form a three-dimensional structure.
Juban, Audrey. "Transformation Induite au cours d’un Procédé Industriel (TIPI) de compression directe : transition polymorphique de la caféine et propriétés physiques des comprimés." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1144/document.
Повний текст джерелаDirect compression process is widely used in the pharmaceutical industry for tablet manufacturing. This work is dedicated to the study of the polymorphic transformation induced by a direct compression process, and its impact on tablet mechanical properties. The main objective is to improve the understanding of the phase transition of caffeine Form I into Form II occurring during the direct compression process, and whether it has an impact on the tablet tensile strength. In this way, several studies have been conducted on the impact of operating conditions on the polymorphic transformation of a model active pharmaceutical ingredient (API) and on few physical properties of the tablets.The use of a compression simulator Styl’One Classique (Médel’Pharm) and a fatigue equipment (Instron®) for the manufacture of tablets, allowed studying two process parameters (compression load and compression speed) and two formulation parameters (dilution of the API and nature of the diluent). Caffeine phase transitions have been evaluated by differential scanning calorimetry (DSC). Moreover, during several months after tableting, kinetic studies were conducted in order to observe the influence of these parameters on the polymorphic transition of the anhydrous caffeine Form I into Form II in tablets during storage. Finally, the analysis of the transition mechanism of this API was performed thanks to a stretched exponential law, derived from the Johnson-Melh-Avrami model.The tensile strength of tablets (global property) was measured by a diametral compression test and their surface hardness (local property) by nanoindentation. A first predictive model for tablet tensile strength according to the caffeine content was developed. The compression cycle characteristics calculated from the data recording with the compression simulator allowed analyzing the behavior of different blends during the compression process. A second model for predicting the tensile strength was then established.Finally, results obtained for the polymorphic transition and physical properties of tablets will then be confronting
Viel, Quentin. "De l'amorphe au cristal : etude d'un composé pharmaceutique chiral." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR048/document.
Повний текст джерелаDuring the last few decades, the field of crystal engineering has gained prominence. Along with the improvement of analytical techniques, the understanding and prediction of crystal structures become more and more accurate. The present work is dedicated to one of the borderline cases encountered that challenge the general understanding of crystallography, polymorphism, phase transition theories and chiral discrimination mechanisms. The chiral pharmaceutical drug diprophylline is one of them, at least for crystallization aspects. Both racemic and enantiopure compositions of this system at the amorphous state have been considered, to carefully study the kinetic transitions with respect to the global molecular mobility. A robust protocol has been established to investigate the molecular mobility by broadband dielectric spectroscopy covering a temperature range of more than 200 °C. The comparative dielectric study of the purified samples proved that the dynamic behaviors of a single enantiomer and of the racemic mixture are very similar; but another secondary relaxation γ was found in samples containing theophylline, the main impurity identified by chromatographic measurements. Additionally, the present study demonstrated that the crystallization from the supercooled melt occurs as a complex multistep process. It involves the homogeneous nucleation and growth of a first population, whose characteristics are highlighted, and which acts as support for the development of secondary populations constituted of metastable solid solutions with higher growth rates. Moreover, the conducted studies demonstrated that at various enantiomeric compositions, the presence of interfaces favored the heterogeneous nucleation of a more stable form
Elander, Nils. "Inflammation-associated genes and genetic variations in colorectal cancer." Doctoral thesis, Linköping : Department of Clinical and Experimental Medicine, Linköping University, 2009. http://www.bibl.liu.se/liupubl/disp/disp2009/med1146s.pdf.
Повний текст джерелаSnoeck, Etienne. "Phases incommensurables de la berlinite et du quartz imagees par microscopie electronique." Toulouse 3, 1986. http://www.theses.fr/1986TOU30067.
Повний текст джерелаSekiya, Tomoko. "Análise do gene CDKN1B/p27kip1 em pacientes com neoplasia endócrina múltipla tipo 2." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5135/tde-26022014-112355/.
Повний текст джерелаINTRODUCTION: In Multiple Endocrine Neoplasia type 2 (MEN2) the development of medullary thyroid carcinoma (MTC), pheochromocytoma (PHEO) and primary hyperparathyroidism (HPT) are associated with activating germline mutations in RET proto-oncogene. Cases of sporadic MTC may have somatic RET mutations (~ 40%). The phenotypic variability observed in cases with familial MTC/MEN2 and PHEO/MEN2 indicates the probable involvement of additional genetic events that could be responsible for the clinical differences observed in the affected individuals (age development, progression and aggressiveness of the tumor). Other genetic alterations such as RET double mutations, SNPs and specific haplotypes may influence susceptibility, aggressiveness and MEN2 phenotype modulation. However, studies of other genes involved in the tumorigenesis of MEN2 are still in progress. Recently, it was shown that the activated RET controls the expression of cell cycle inhibitory proteins (p18 and p27). Germline mutations in the p27 gene have recently been associated with the susceptibility to neuroendocrine tumors and are associated with the MEN4 syndrome (Multiple endocrine neoplasia type 4). Somatic inactivating mutations p27 are rarely found in many types of tumors. However, several studies have documented that reduced expression and subcellular location of p27 is controlled by post-transductional changes and/or epigenetic factors. OBJECTIVES: This study aimed to evaluate the role of genes recently associated with RET activated in tumors from MEN2 patients and also check whether polymorphisms in the p27 gene would be acting as modulators of phenotype in a large MEN2 family. PATIENTS: We analyzed 66 tumor samples from 36 patients with clinical and genetic diagnosis of MEN2 and from 28 individuals belonging to a large family with FMTC/MEN2A and RET C620R mutation. METHODS: The analyses of somatic p27, p15, p18 and RET were performed by PCR and direct sequencing of DNA and microsatellite analysis was performed for p27 by PCR and capillary electrophoresis. Expression analysis and subcellular localization of p27 protein were performed by Western blot and immunohistochemistry. The analysis of phenotype modulation in MEN2A families was performed by the amplification of exon 1 of the p27 gene in a whole blood sample. RESULTS: There were no somatic mutations in the p27 gene and also in the p15 and p18 genes. However, we verified a low p27 protein expression in MTC/MEN2 and PHEO/MEN2 that showed a definite correlation with the type and aggressiveness of the mutated RET codon, mainly in those tumors from cases with germline RET codon 634 mutations (control vs 634, p=0,05; control vs 634/791, p= 0,032; 620 vs 634, p=0,045; 620 vs 634/791, p= 0,002; 620 vs 634 + 634/791, p=0,036). It was also verified a positive correlation between the immunohistochemistry expression of nuclear p27 subcellular location and the p27 p.V109G TT genotype (p=0,03). CONCLUSIONS: The reduction in the expression of p27 and its subcellular localization are likely to be associated with somatic changes in other genes that control the processes of phosphorylation of p27 protein through post-transductional events
Strege, Christine [Verfasser]. "On (pseudo-) polymorphic phase transformations / von Christine Strege." 2004. http://d-nb.info/974120006/34.
Повний текст джерелаTrunov, Mikhaylo Aleksiyovych. "Effect of polymorphic phase transformations within an alumina layer on the ignition of aluminum particles." Thesis, 2006. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2006-086.
Повний текст джерелаKulkarni, Chaitrali S., John Kendrick, Adrian L. Kelly, Timothy D. Gough, Radha C. Dash, and Anant R. Paradkar. "Polymorphic transformation of artemisinin by high temperature extrusion." 2013. http://hdl.handle.net/10454/6059.
Повний текст джерелаThis communication reports a novel solvent free method to generate and stabilise the triclinic form of artemisinin. We show that the stability of the triclinic form obtained by high temperature extrusion is greater than that of material made using a solvent based technique.
Kulkarni, Chaitrali S., Adrian L. Kelly, John Kendrick, Timothy D. Gough, and Anant R. Paradkar. "Mechanism for Polymorphic Transformation of Artemisinin during High Temperature Extrusion." 2013. http://hdl.handle.net/10454/9678.
Повний текст джерелаA novel, green, and continuous method for solid-state polymorphic transformation of artemisinin by high temperature extrusion has recently been demonstrated. This communication describes attempts to understand the mechanisms causing phase transformation during the extrusion process. Polymorphic transformation was investigated using hot stage microscopy and a model shear cell. At high temperature, phase transformation from orthorhombic to the triclinic crystals was observed through a vapor phase. Under mechanical stress, the crystalline structure was disrupted continuously, exposing new surfaces and accelerating the transformation process.
Maher, A., D. M. Croker, Colin C. Seaton, Å. C. Rasmuson, and B. K. Hodnett. "Solution-Mediated Polymorphic Transformation: Form II to Form III Piracetam in Organic Solvents." 2014. http://hdl.handle.net/10454/10191.
Повний текст джерелаThe solution-mediated polymorphic transformation from Form II to Form III 2-oxo-1-pyrrolidine acetamide (piracetam) was investigated in seven organic solvents over the temperature range of 5–50 °C. The transformation rate increased as a function of temperature, agitation, and the solubility of piracetam in the host solvent. However, this trend was reversed in 2-propanol. Molecular modeling demonstrated that 2-propanol forms interactions with piracetam molecules in solution stronger than those formed by other solvents, thereby retarding the nucleation and growth of FIII(6.525) during the transformation in this solvent.
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Omondi, Bernard. "The influence of weak interactions on phase transformations and polymorphism in distributed n-aryl -formamides and -thioamides." Thesis, 2008. http://hdl.handle.net/10539/5899.
Повний текст джерелаBlagden, Nicholas, S. W. Booth, Matos Luciana L. De, and Adrian C. Williams. "Solvent influences on Metastable Polymorph Lifetimes:Real-time interconversions using Energy Dispersive X-Ray Diffractometry." 2007. http://hdl.handle.net/10454/4120.
Повний текст джерелаSolvent influences on the crystallization of polymorph and hydrate forms of the nootropic drug piracetam (2-oxo-pyrrolidineacetamide) were investigated from water, methanol, 2-propanol, isobutanol, and nitromethane. Crystal growth profiles of piracetam polymorphs were constructed using time-resolved diffraction snapshots collected for each solvent system. Measurements were performed by in situ energy dispersive X-ray diffraction recorded in Station 16.4 at the synchrotron radiation source (SRS) at Daresbury Laboratory, CCLRC UK. Crystallizations from methanol, 2-propanol, isobutanol, and nitromethane progressed in a similar fashion with the initial formation of form I which then converted relatively quickly to form II with form III being generated upon further cooling. However, considerable differences were observed for the polymorphs lifetime and both the rate and temperature of conversion using the different solvents. The thermodynamically unstable form I was kinetically favored in isobutanol and nitromethane where traces of this polymorph were observed below 10°C. In contrast, the transformation of form II and subsequent growth of form III were inhibited in 2-propanol and nitromethane solutions. Aqueous solutions produced hydrate forms of piracetam which are different from the reported monohydrate; this crystallization evolved through successive generation of transient structures which transformed upon exchange of intramolecular water between the liquid and crystalline phases
Chow, P. S., G. Lau, W. K. Ng, and Venu R. Vangala. "Stability of Pharmaceutical Cocrystal During Milling: A Case Study of 1:1 Caffeine-Glutaric Acid." 2017. http://hdl.handle.net/10454/12360.
Повний текст джерелаDespite the rising interest in pharmaceutical cocrystals in the past decade, there is a lack of research in the solid processing of cocrystals downstream to crystallization. Mechanical stress induced by unit operations such as milling could affect the integrity of the material. The purpose of this study is to investigate the effect of milling on pharmaceutical cocrystal and compare the performance of ball mill and jet mill, using caffeine-glutaric acid (1:1) cocrystal as the model compound. Our results show that ball milling induced polymorphic transformation from the stable Form II to the metastable Form I; whereas Form II remained intact after jet milling. Jet milling was found to be effective in reducing particle size but ball milling was unable to reduce the particle beyond certain limit even with increasing milling intensity. Heating effect during ball milling was proposed as a possible explanation for the difference in the performance of the two types of mill. The local increase in temperature beyond the polymorphic transformation temperature may lead to the conversion from stable to metastable form. At longer ball milling duration, the local temperature could exceed the melting point of Form I, leading to surface melting and subsequent recrystallization of Form I from the melt and agglomeration of the crystals. The findings in this study have broader implications on the selection of mill and interpretation of milling results for not only pharmaceutical cocrystals but pharmaceutical compounds in general.
Ali, H. R. H., Howell G. M. Edwards, Michael D. Hargreaves, Tasnim Munshi, Ian J. Scowen, and Richard Telford. "Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry." 2008. http://hdl.handle.net/10454/17381.
Повний текст джерелаKnowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting β-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488–1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectro-scopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control.
Saluja, Gaurav. "Experimental Study of Patterns in Hydrodynamically Deposited Dispersed Phase of CaCO3 on Surfaces of Straight Cylindrica Silica Tubing." Thesis, 2015. http://etd.iisc.ernet.in/2005/3955.
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