National Repository of Grey Literature 5,221 records found  1 - 10nextend  jump to record: Search took 0.67 seconds. 


Micro-electromembrane extraction across multiple aqueous and organic phases for selective pretreatment of raw biological samples
Kubáň, Pavel ; Boček, Petr ; Seip, K. F. ; Gjelstad, A. ; Pedersen-Bjergaard, S.
Micro-electromembrane extraction (μ-EME) across multiple aqueous and organic\nsolutions was developed for selective extractions of various analytes from untreated\nbiological samples. The novel approach requires μL volumes of samples and organic\nsolvents, which form consecutive immiscible plugs in a transparent polymeric capillary\nand the extraction process is accelerated by application of d.c. voltage. Number of the\nplugs, their composition, volume and sequence in the extraction capillary can be chosen\nspecifically for each particular application and high variability and selectivity of the\nextraction process can be achieved. In this contribution, we demonstrate suitability of\na five-phase μ-EME system for simultaneous extractions of cations and anions from\nurine and for selective extractions of basic analytes based on their acid-base strength\nfrom plasma.

Parallel single-cell analysis of active caspase-3/7 in apoptotic and non-apoptotic cells
Ledvina, Vojtěch ; Klepárník, Karel
Caspases are proteases that play key role in the process of apoptosis, the programmed\ncell death. Among them, caspase-3 and -7 are main executioner caspases that cleave\nmany vital proteins during apoptosis and after their widespread activation, the process\ncannot be reversed. To analyze caspase-3/7 activation within single cells, a miniaturized\ndevice for parallel analysis of eight samples was developed. The assay is based on the\nmodified luciferin-firefly luciferase bioluminescence (BL) system. Individual\nsuspended cells were collected and transferred into detection microvials using a\nmicromanipulator. The bioluminescence was detected using a photon counting head\nwith cooled photcathode. The LOD suitable for detection of active caspase-3/7 in both\napoptotic and non-apoptotic cells was reached.

Determination of content substances for selected species and varieties of roses.
Slavíková, Eva ; Sus, Josef (advisor) ; Súkeníková, Tereza (referee)
This bachelor's work is focused on comparing the most significant content substance, vitamin C, in fruits of chosen rose kinds species and varieties. Herbal products are often seen by people as products of "second choice", when failure of allopathic treatment occurs, which is focused especially on suppressing symptoms of illness, but it ignores health of the human body as whole. That's why are herbal products often alternative for therapy of chronic diseases. The base of this work is extensive literary research and results of laboratory measurings. Literary part of this work includes description of botanical classification of rose plants. There is stated basic characteristic of individual rose species and their morphological features. In following chapters is composed overview of effective substances in rose fruits and their effect on human health. In practical part of this work are included results of laboratory tests for determining ascorbic acid content for chosen samples of rose species and it also includes results of weighing and measuring of fruit samples of chosen rose species. There are also stated chosen rose species and shortly their origin and description, in the beginning of practical part. For practical part were chosen samples of species. Results of practical part are compiled into statistic tables and graphs and it confirms high content of ascorbic acid in rose fruits. This content is in range of cca 300 - 900 mg.100 g-1. Due to growing interest in alternative treatment options and "clean" natural product, it can be assumed, that many plants of Rosaceae family will keep its place in treatment practice. Those plants will be used not only for treatment of acute and chronic diseases, but also for cosmetic products production, thanks to its large effects and process options.

Nutritional analysis and optimization of breeding of selected species of edible insects under conditions of the Czech Republic with regard to human health
Adámková, Anna ; Kouřimská, Lenka (advisor)
All over the world, the edible insects are considered a highly nutritious food with high protein and fat content. However, the nutritional value of insect is not constant. It can be affected by species, developmental stage, rearing technology or nutrition. Therefore, this thesis was aimed at obtaining the selected nutritional value of edible insects. Analyses were focused on the determination of the crude protein content, fat content, fatty acid profile and sterols in selected species of edible insects, which can be commonly reared in the Czech Republic. At the same time we also analysed samples of insects reared on the island of Sumatra to evaluate the influence of the climate on the nutritional value. The main aim of the thesis was the determination of optimal breeding conditions, developmental stages and feed rations for obtaining good production of insects with nutritional properties suitable for human nutrition. The analyses showed a high nutritional value of selected insect species, but also confirmed the significant differences in the content of individual nutrients between different species depending on the climate conditions and developmental stage. Comparing the fat and crude protein content in edible insects and other conventional sources of meat it has been found, that the examined insect is similar to beef concerning the fat and crude protein content. The results obtained are the basis for determining the appropriate rearing conditions and developmental stages for obtaining insect with the desired nutritional properties for human nutrition.

Antioxidant, anti-proliferative and immunomodulatory effect of fruits, vegetables and mushrooms in vitro
Doskočil, Ivo ; Havlík, Jaroslav (advisor) ; Orsák, Matyáš (referee)
Recently there has been an increasing interest in discovering of new species of plants and mushrooms which have antioxidant or anti proliferative activity. The interest is caused by the fact that these species have medicinal and food utilization. These properties of plants and mushrooms can be used when dealing with many diseases which may be connected with oxidative stress (inflammatory bowel disease, cardiovascular disease, hypertension, and tumour disease, etc.). The thesis propounds characteristics of in vitro antioxidant and anti proliferative activity of 19 types of juices and 28 methanol extracts of fruits and vegetables, which are common parts of a diet. In the thesis there are also characteristics of 13 ethanol extracts of edible mushrooms of the order of Polypore (Popyporales). Antioxidant activity was quantifie by 2, 2 diphenyl 1 picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and inhibition of nitric oxide (NO) production. Cytotoxicity was measured by MTT (3 (4,5 dimethylthiazol 2 yl) 2,5 diphenyltetrazolium bromide. Immunomodulatory activity was determined by an assay of phagocytic activity of human neutrophil granulocytes. Further a total phenolic content (TPC) and total beta glucan content were investigated; these are considered to be the potentially active constituents participating in mentioned activities. From the obtained results it is evident that juices (TPC = 1603.2 mg GAE/L; ORAC = 438.5 umol TE/g) and a bilberry (Vaccinium myrtillus) fruit extract (ORAC 836.6 umol TE/g; DPPH = 404.6 umol TE/g) showed the highest antioxidant activity of all tested samples of fruits and vegetables. Capsicum (Capsicum L.) juices (TPC = 642.1 mg GAE/L; ORAC = 127.9 umol TE/g) and a radish (Raphanus sativus L.) extract (ORAC 724.5 umol TE/g; DPPH = 52.2 umol TE/g) also proved to have the high values of antioxidant activity. From the tested fruits and vegetables the following inhibited to produce a nitric oxide: onion (Allium cepa L) juices (lowered the NO production by 57%), tangerine juices (Citrus reticulata Blanco)(by 52%), broccoli (Brassica oleracea var. botrytis italic) extract (by 21%), and orange (Citrus sinensis Pers.) extract (by 10%). Concerning edible mushrooms, Lentinus tigrinus (Bull.) Fr. (TPC = 216.2 umol GAE/g of extract), Ganoderma lucidum (Curtis) P. Kras (TPC = 257.9 umol GAE/g of extract), and Royoporus badius (Pers.) A.B. De (TPC = 257.8 umol GAE/g of extract) presented the highest phenolic content. Sparassis crispa (Wulfen) Fr. (117.4 mg/g of extract) had the highest content of beta glucan. Substantial effect on phagocytic activity of granulocytes was noticed in connection with Neolentinus lepideus (Fr.) Redhead & Ginns, Polyporus squamosus (Huds.) Fr., and S. crispa. In connection with the latter of mentioned mushrooms, a moderate inhibitory effect towards HT 29 human colorectal adenocarcinoma cell line (IC50 = 107 ug/ml of extract) was noticed. The results indicate that the tested plants and mushrooms can be beneficial when reducing the negative effects of oxidative stress. The oxidative stress has been recognized as a contributing factor to a whole range of diseases and the reduction of the oxidative stress may lead to the decrease in the possibility of the diseases´ progression. The results show the possible favourable effects on the human health. When evaluating the results, the following fact should be taken into consideration; the in vitro tests and screenings are considered to be the first phase of systematic research of the effects and serve for the choice of respondents for further detailed studies.

Non-invasive methods for sex and steroid homones determination in gibbons of the genus Nomascus
Bolechová, Petra ; Bartoš, Luděk (advisor) ; Pavel, Pavel (referee)
The gibbon primates of the family Nomascus are classified as critically endangered species, and, to date, basic understanding and information about their biology is missing. With regard to the status of these animals in the wild and captive populations in zoos, being familiar with their reproduction, may improve captive breeding programs. Data collection in this study was to be carried out by the practical use of non-invasive methods (polymerase chain reaction for DNA extraction and enzyme immunoassays), using faecal samples for analysis. The first method, polymerase chain reaction, was used for sex determination in juveniles, because of their coat colour and visual similarity of secondary sex characteristic in both sexes; it is not possible to determinate sex without handling the animal. Another main purpose of this study is to try and answer the hypothesis regarding the ovarian cycle of females, factors influencing their hormone concentration and also the onset of sexual maturity in females and the timing of their fur colour change. Hypotheses were checked by monitoring the concentration of progesterone and oestrogen faecal metabolites and by evaluation of the composition of breeding groups of gibbons with the ZOO influence. During a four year period (from 2010 till 2014), there were a total of 51 animals analysed from 16 different zoos with a faecal sample count totalling 1618 samples. The results confirmed the use of noninvasive methods for sex determination, and thus ensuring the maximum welfare standards. Endocrinological analysis confirmed the hypothesis of the influence of the environment (ZOO) to the hormone concentrations and female´s pregnancy effect in conjunction with her age on the final results of the male - father hormone concentrations. The initial information in this study is the confirmation of the onset of ovarian cycle in young females without connection to their fur colour change and a significant factor of a mother´s impact and her territoriality. This study is the first to present a long term monitoring of ovarian cycles in females and hormone concentrations of other individuals, both male and female, and from various age groups. The results allow us to understand the possible impact of zoo environments on the reproductive status of these gibbons and contribute to the general improvement of breeding management.

Single particle analysis of size-segregated aerosol in Prague city center
Marvanová, S. ; Skoupý, Radim ; Kulich, P. ; Bendl, J. ; Hovorka, J. ; Machala, M.
Particulate matter (PM) is omnipresent pollutant in the ambient air known to cause cardiovascular and respiratory diseases (WHO 2004). Recently, outdoor air pollution and particulate matter in outdoor air pollution were classified as carcinogenic to humans, Group 1 (IARC 2015). Especially, ambient PM of aerodynamic diameter < 100 nm, ultrafine particles, appears to be of great importance due to its high specific surface area and high number concentration (Hughes et al. 1998). Ultrafine particles also easily enter and are being transferred in organisms, and interact with cells and subcellular components (Oberdorster et al. 2005). As the evidence of ultrafine PM significance increased, size-fractionated PMs sampled by various cascade impactors have been employed into the toxicological studies on cell cultures or isolated cells, using the organic extracts of size-fractionated PMs (Topinka et al. 2013, Topinka et al. 2015) or directly the size-fractionated particles (Becker et al. 2003, Ramgolam et al. 2009, Reibman et al. 2002, Loxham et al. 2013, Jalava et al. 2006, Thomson et al. 2015, Jalava et al. 2015). The aim of this study was to evaluate shape and composition of size-segregated aerosol particles, sampled by high volume cascade impactor, using electron microscopy and energy dispersive X-ray spectroscopy (EDX).

Time lapse tomography of fracture progress in silicate-based composite subjected to the loading a combination with acoustic emission scanning
Kumpová, Ivana ; Kytýř, Daniel ; Fíla, Tomáš ; Veselý, V. ; Trčka, T. ; Vopálenský, Michal ; Vavřík, Daniel
The initiation and propagation of a fracture in quasi-brittle materials (such as silicatebased composite) is an increasingly discussed topic for which various methods of research have been developed/applied. As the quasi-brittle silicate-based composite compounds are very non-homogenous, the mechanism of the crack initiation and propagation can be very different even for samples with the\nidentical geometry. One possible approach to study the fracture mechanism in quasi-brittle materials is to use several different experimental techniques in a single experiment and perform detail analysis to identify generally valid fracture process phenomena. In this work, a simultaneous monitoring of fracture\nprocess zone formation and propagation by three different methods is presented and discussed. A three point bending test was performed on a notched silicate composite specimen. During the loading process, a highly accurate force displacement dependence was recorded accompanied with X-ray radiography,\nX-ray computed tomogra-phy and acoustic emission scanning.

Noise, Transport and Structural Properties of High Energy Radiation Detectors Based on CdTe
Šik, Ondřej ; Lazar, Josef (referee) ; Navrátil, Vladislav (referee) ; Grmela, Lubomír (advisor)
Poptávka ze strany vesmírného výzkumu, zdravotnictví a bezpečnostního průmyslu způsobila v posledních letech zvýšený zájem o vývoj materiálů pro detekci a zobrazování vysokoenergetického záření. CdTe a jeho slitina CdZnTe. jsou polovodiče umožnují detekci záření o energiích v rozsahu 10 keV až 500 keV. Šířka zakázaného pásma u CdTe / CdZnTe je 1.46 -1.6 eV, což umožňuje produkci krystalů o vysoké rezistivitě (10^10-10^11 cm), která je dostačující pro použití CdTe / CdZnTe při pokojové teplotě. V mé práci byly zkoumány detektory CdTe/CdZnTe v různých stádiích jejich poruchovosti. Byly použity velmi kvalitní spektroskopické detektory, materiál s nižší rezistivitou a výraznou polarizací, detektory s asymetrií elektrických parametrů kontaktů a teplotně degenerované vzorky. Z výsledků analýzy nízkofrekvenčního šumu je patrný obecný závěr, že zvýšená koncentrace defektů způsobí změnu povahy původně monotónního spektra typu 1/f na spektrum s výrazným vlivem generačně-rekombinačních procesů. Další výrazná vlastnost degenerovaných detektorů a detektorů nižší kvality je nárůst spektrální hustoty šumu typu 1/f se vzrůstajícím napájecím napětí se směrnicí výrazně vyšší než 2. Strukturální a chemické analýzy poukázaly, že teplotní generace detektorů způsobuje difuzi kovu použitého při kontaktování a stopových prvků hlouběji do objemu krystalu. Část mé práce je věnována modifikaci povrchu svazkem argonových iontů a jejímu vlivu na chemické složení a morfologii povrchu.