The aim of this work was the evaluation and method optimalization for determination of sulfates in aqueous solutions with application on different kinds of waters. For determination of sulfates were used two different procedures, turbidimetric and volumetric. In turbidimetric procedure was use optimized conditions applicable determination of sulfates in range from 0 – 20 mg.l-1. For stabilization of the colloid was use glycerine, himself sulfates sedimentation is discharged in BaSO4 form. By volumetric methods are used titration on the dithizone like indicator while using Pb(NO3)2 like volumetric reagent. Other indicator bromsulfonazo III, whitch are used for determination of sulfates by the help of volumetric solutions Ba(ClO4)2 and BaCl2. All volumetric determinations proceeded in acidic medium. During research of interferences ions on the individual titraction was detected substantial effect Ca2+, Mg2+ and Fe3+, which was needing divide off on the exchanger resin. Ions aforementioned don't interfere turbidimetric determination of sulfates.

L’incorporation de silice, obtenue par un procédé de précipitation en milieu aqueux, à la bande de roulement des pneumatiques a permis d’en réduire significativement la résistance au roulement et par conséquent, l’impact environnemental. L’efficacité de la silice précipitée en tant que charge de renfort est liée à la présence d’agrégats nanométriques au sein de ce matériau et à son interaction avec l’élastomère du pneumatique. La maîtrise de la morphologie des agrégats est donc un levier pour le développement de silices plus performantes. Dans ce contexte, la présente étude porte sur le développement d’un modèle prédictif de la formation de l’agrégat de silice au cours de la précipitation. Un suivi par turbidimétrie en ligne et par DLS a permis d’illustrer l’influence critique des paramètres de synthèse sur la cinétique d’agrégation. Un modèle optique basé sur les propriétés diffusantes des objets fractals a été développé pour extraire des informations morphologiques sur l’agrégat au cours de sa construction à partir des spectres de turbidité expérimentaux. Les résultats semblent indiquer une densification de la structure au fur et à mesure que se déroule l’agrégation. Les analyses de porosimétrie azote et mercure menées sur les produits finaux, obtenus après séchage, ont quant à elles mis en évidence des différences texturales qui ont pu être mises en lien avec la cinétique d’agrégation. L’ensemble de ces informations a été repris dans un bilan de population permettant de traiter à la fois la croissance et l’agrégation des particules de silice ainsi que de simuler les propriétés optiques de la suspension. / Tires manufactured with precipitated silica instead of carbon black present a significantly lower rolling resistance and are therefore more environmentally friendly. Existence of nanometric aggregates inside the precipitated silica is responsible for its efficiency as a reinforcing filler. This level of structure deeply affects the quality of the interactions between silica and the rubber of the tire tread. Gaining control over the morphology of the aggregates could thus be a way to produce silica even more suited to this application.The aim of the present study is to develop a theoretical model able to predict the formation of silica aggregates during the precipitation process. Critical influence of the synthesis parameters on the aggregation kinetics were evidenced by DLS and online turbidimetry measurements. Morphological parameters of the expanding aggregates could be extracted from the experimental turbidity spectra thanks to a fractal scattering optical model. The observed trend suggested a densification of the aggregates over time. Nitrogen and mercury porosimetry analyses were carried out on the dried powders obtained at the end of the precipitation. Differences between the characterized samples could be related to the variations in their aggregation kinetics. Finally, a population balance model was developed. A specific feature of our model is that it is able to take into account both growth and aggregation of silica particles as well as to simulate their optical properties.

Background: The method of serum bactericidal assay represents an alternative possibility of optimization of anti-infectious therapy and administration of antibiotics. It mirrors the real activity of one or more administered antibiotics in the complex system of the antibacterial effect of patient's serum. The paper aimed to confirm non-inferiority of bactericidal testing using the broth dilution method according to CLSI M21-A Guidelines (time to results 48, 72 hours) in comparison with modified methods of testing on the basis of turbidimetry (time to result 6, 8, 24 hours) and resazurin color (time to results 8, 24 hours). Methods: Four antibiotics were tested: gentamicin, amikacin, piperacillin/tazobactam and meropenem with 30 Escherichia coli strains isolated from blood cultures of 29 pacients hospitalised in different wards, University Hospital in Hradec Kralove. Human blood sera (n = 76) from ten hematological patients (4th Department of Clinical Medicine, University Hospital, Hradec Kralove) were tested to establish bactericidal titer. Patients' blood was withdrawn prior to and in the course of the first and third day of antibiotic therapy of febrile neutropenia. Testing employed the reference strain Escherichia coli ATCC 25922. Results: A comparison with the standard CSLI showed that the...

Three-dimensional fibrillar networks reconstituted from collagen I are widely used as biomimetic scaffolds for in vitro and in vivo cell studies. Various physicochemical parameters of buffer conditions for in vitro fibril formation are well known, including pH-value, ion concentrations and temperature. However, there is a lack of a detailed understanding of reconstituting well-defined 3D network topologies, which is required to mimic specific properties of the native extracellular matrix. We screened a wide range of relevant physicochemical buffer conditions and characterized the topology of the reconstituted 3D networks in terms of mean pore size and fibril diameter. A congruent analysis of fibril formation kinetics by turbidimetry revealed the adjustment of the lateral growth phase of fibrils by buffer conditions to be key in the determination of pore size and fibril diameter of the networks. Although the kinetics of nucleation and linear growth phase were affected by buffer conditions as well, network topology was independent of those two growth phases. Overall, the results of our study provide necessary insights into how to engineer 3D collagen matrices with an independent control over topology parameters, in order to mimic in vivo tissues in in vitro experiments and tissue engineering applications.

A adesão de plaquetas nas paredes dos vasos sanguíneos e subsequente agregação são eventos cruciais tanto na hemorragia e quanto na trombose. A hiperagregação (agregação excessiva) das plaquetas pode causar a formação de um trombo e a posterior oclusão dos vasos sanguíneos levando a um processo isquêmico. A terapia antiplaquetária com ácido acetilsalicílico reduz em até 25% o risco de infartos do miocárdio não-fatais, acidentes vasculares cerebrais isquêmicos ou mortes de causa vascular em pacientes de alto risco, independentemente do sexo ou idade. Para avaliar laboratorialmente a eficácia dessa terapêutica, o método mais utilizado é o teste de agregação plaquetária, que pode ser feito em duas metodologias, a turbidimétrica e a por impedância elétrica. Com esse cenário, o objetivo do estudo é comparar essas duas metodologias para a monitorização do tratamento. Para isso foram utilizadas amostras de sangue de 30 pacientes adultos (média de 42 anos) de ambos os sexos que fazem uso regular do fármaco e analisadas através das duas metodologias, tendo seus resultados analisados e comparados. Os resultados do estudo mostraram pouca diferença estatística significante (p<0,05) entre os dois métodos nos principais agentes estimulantes, indicando que o método de impedância elétrica pode ser utilizado em rotina laboratorial em substituição, ou em complementação, com a metodologia turbidimétrica para monitorar a terapia antiplaquetária a base de ácido acetilsalicílico / The adhesion of platelets in the blood vessel wall and subsequent aggregation are crucial events in both bleeding and thrombosis. The hyperaggregation (excessive aggregation) of platelets can cause the formation of a thrombus and subsequent occlusion of blood vessels leading to an ischemic process. Antiplatelet therapy with acetylsalicylic acyd reduces by 25% the risk of myocardial infarctions, non-fatal strokes or deaths from vascular causes in patients at high risk, regardless of sex or age. To laboratory evaluation of the effectiveness of this therapy, the method most used is the platelet aggregation test, which can be done in two methods, the turbidimetric and electrical impedance. With this scenario, the objective of the study is to compare these two methodologies for monitoring the treatment. For such purpose, blood samples from 30 adult patients (mean 42 years) of both sexes who make regular use of the drug was analyzed using the two methodologies, and their results was analyzed and compared. The studys results showed little difference statistically significant (p <0.05) between the two methods with the main stimulant agents, indicating that the method of electrical impedance can be used in routine laboratory instead or complementing the methodology of turbidimetric for monitor antiplatelet therapy by acetylsalicylic acyd

A adesão de plaquetas nas paredes dos vasos sanguíneos e subsequente agregação são eventos cruciais tanto na hemorragia e quanto na trombose. A hiperagregação (agregação excessiva) das plaquetas pode causar a formação de um trombo e a posterior oclusão dos vasos sanguíneos levando a um processo isquêmico. A terapia antiplaquetária com ácido acetilsalicílico reduz em até 25% o risco de infartos do miocárdio não-fatais, acidentes vasculares cerebrais isquêmicos ou mortes de causa vascular em pacientes de alto risco, independentemente do sexo ou idade. Para avaliar laboratorialmente a eficácia dessa terapêutica, o método mais utilizado é o teste de agregação plaquetária, que pode ser feito em duas metodologias, a turbidimétrica e a por impedância elétrica. Com esse cenário, o objetivo do estudo é comparar essas duas metodologias para a monitorização do tratamento. Para isso foram utilizadas amostras de sangue de 30 pacientes adultos (média de 42 anos) de ambos os sexos que fazem uso regular do fármaco e analisadas através das duas metodologias, tendo seus resultados analisados e comparados. Os resultados do estudo mostraram pouca diferença estatística significante (p<0,05) entre os dois métodos nos principais agentes estimulantes, indicando que o método de impedância elétrica pode ser utilizado em rotina laboratorial em substituição, ou em complementação, com a metodologia turbidimétrica para monitorar a terapia antiplaquetária a base de ácido acetilsalicílico / The adhesion of platelets in the blood vessel wall and subsequent aggregation are crucial events in both bleeding and thrombosis. The hyperaggregation (excessive aggregation) of platelets can cause the formation of a thrombus and subsequent occlusion of blood vessels leading to an ischemic process. Antiplatelet therapy with acetylsalicylic acyd reduces by 25% the risk of myocardial infarctions, non-fatal strokes or deaths from vascular causes in patients at high risk, regardless of sex or age. To laboratory evaluation of the effectiveness of this therapy, the method most used is the platelet aggregation test, which can be done in two methods, the turbidimetric and electrical impedance. With this scenario, the objective of the study is to compare these two methodologies for monitoring the treatment. For such purpose, blood samples from 30 adult patients (mean 42 years) of both sexes who make regular use of the drug was analyzed using the two methodologies, and their results was analyzed and compared. The studys results showed little difference statistically significant (p <0.05) between the two methods with the main stimulant agents, indicating that the method of electrical impedance can be used in routine laboratory instead or complementing the methodology of turbidimetric for monitor antiplatelet therapy by acetylsalicylic acyd

The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.

The diploma thesis deals with the preparation and characterization of catanionic complexes and their possible application to pharmaceutics and medicine. The catanionic complexes were prepared by mixing two oppositely charged surfactants with the concentration of 20 mmol·dm­3 in various volume ratios. Two systems were analyzed – CTAB + SDS and Septonex + SDS. Both systems were prepared in an aqueous and physiological environment. The turbidimetric analyses provided results of the intensity of turbidity of the prepared mixtures. The size and stability of the prepared particles were determined by DLS and ELS measurements. CTAB-rich samples showed significant viscosity changes and they were therefore characterized by rheological measurements. The results of this work show that the asymmetry of alkyl chains, surfactant selection, temperature, and ionic strength have a significant influence on the properties and self-assembly of surfactants in catanionic complexes.

The study deals with interactions of polyelectrolytes polystyrene sulfonate and hyaluronic acid with nitrogenic amphiphilic substances, represented by lysine and albumine. To study the interactions pH-metry, conductance, viscositic and turbidity measurement, DLS and reometry were used. All mixtures of different concentrations were measured and the data were compered with data obtained from measurement of samples with amphiphilic sumstances without polyelectrolytes. Observed interactions occured in the aminoacid concentrations between 0 to 20 mmoldm-3, then the PSS interaction groups were fully bonded by lysine and no more interactions were recognized. The same behaviour were observed in albumine solutions with concentration under 2 gdm-3.

The master’s thesis discusses the comparison of microbial metabolic production from waste and powder whey. Whey is obtained as a by-product of cheese production. Lactose (preferably whey) using lactic acid bacteria (eg. Lactobacillus) under suitable temperature conditions is converted to lactic acid. Effect of temperature, effect of salts and effect of yeast extract on lactic acid production by L. casei were investigated. HPLC metod was determined lactid acid. In the practical part were used bacteria of the genus Lactobacillus. It was found that for dried and waste whey is the optimal temperature of 35 °C. At this temperature is the greatest gain of lactic acid. The highest concentration of lactic acid was obtained by using 20 g of yeast extract for dried whey and for waste whey were used 24 g of yeast extract. When monitoring the effect of salt concentration on the production of lactic acid, it was found that using only MnSO4·H2O gain most of lactic acid.