near-surface temperatures
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An advanced surface engineering process combining micro-texture with a plasma carburising process was produced on CoCrMo femoral head, and their tribological properties were evaluated by the cutting-edge pendulum hip joint simulator coupled with thin film colorimetric interferometry. FESEM and GDOES showed that precipitation-free C S-phase with a uniform case depth of 10μm was formed across the micro-textures after duplex treatment. Hip simulator tests showed that the friction coefficient was reduced by 20% for micro-metre sized texture, and the long-term tribological property of microtexture was enhanced by the C-supersaturated crystalline microstructure formed on the surface of duplex treated CoCrMo, thereby enhancing biotribological durability significantly. In-situ colorimetric interferometry confirmed that the maximum film thickness around texture area was 530nm, indicating that the additional lubricant during sliding motion might provide exceptional bearing life.
Frozen aqueous solutions are an important subject of study in numerous scientific branches including the pharmaceutical and food industry, atmospheric chemistry, biology, and medicine. Here, we present an advanced environmental scanning electron microscope methodology for research of ice samples at environmentally relevant subzero temperatures, thus under conditions in which it is extremely challenging to maintain the thermodynamic equilibrium of the specimen. The methodology opens possibilities to observe intact ice samples at close to natural conditions. Based on the results of ANSYS software simulations of the surface temperature of a frozen sample, and knowledge of the partial pressure of water vapor in the gas mixture near the sample, we monitored static ice samples over several minutes. We also discuss possible artifacts that can arise from unwanted surface ice formation on, or ice sublimation from, the sample, as a consequence of shifting conditions away from thermodynamic equilibrium in the specimen chamber. To demonstrate the applicability of the methodology, we characterized how the true morphology of ice spheres containing salt changed upon aging and the morphology of ice spheres containing bovine serum albumin. After combining static observations with the dynamic process of ice sublimation from the sample, we can attain images with nanometer resolution.
The combination of nanoparticles with the polymerase chain reaction (PCR) can have benefits such as easier sample handling or higher sensitivity, but also drawbacks such as loss of colloidal stability or inhibition of the PCR. The present work systematically investigates the interaction of magnetic iron oxide nanoparticles (MIONs) with the PCR in terms of colloidal stability and potential PCR inhibition due to interaction between the PCR components and the nanoparticle surface. Several types of MIONs with and without surface functionalisation by sodium citrate, dextran and 3-aminopropyl-triethoxysilane (APTES) were prepared and characterised by Transmission Electron Microscopy (TEM), dynamic light scattering (DLS) and Fourier Transform Infrared (FT-IR) spectroscopy. Colloidal stability in the presence of the PCR components was investigated both at room temperature and under PCR thermo-cycling. Dextran-stabilized MIONs show the best colloidal stability in the PCR mix at both room and elevated temperatures. Citrate- and APTES-stabilised as well as uncoated MIONs show a comparable PCR inhibition near the concentration 0.1mgml(-1) while the inhibition of dextran stabilized MIONs became apparent near 0.5mgml(-1). It was demonstrated that the PCR could be effectively carried out even in the presence of elevated concentration of MIONs up to 2mgml(-1) by choosing the right coating approach and supplementing the reaction mix by critical components, Taq DNA polymerase and Mg(2+) ions.
Navození terapeutické mírné hypotermie zlepšuje prognózu nemocných úspěšně resuscitovaných pro srdeční zástavu. K ochlazení pacientů, k udržení správného terapeutického rozmezí tělesné teploty a k následnému pomalému dosažení a udržení normotermie existuje řada neinvazivních i invazivních metod s různou účinností. Jednoduchými a zároveň nejpoužívanějšími postupy jsou povrchové ochlazování ledovými obklady a rychlá nitrožilní aplikace chladného krystaloidního roztoku. Sofistikovanější matracové systémy pro povrchové ochlazování a soustavy pro endovaskulární katetrové chlazení jsou finančně nákladnější, ale zaručují především jednoduchou obsluhu a přesnější titraci cílové terapeutické teploty. Jako doplňkové metody mohou sloužit chladicí helmy nebo čepice vedoucí k selektivnímu ochlazování hlavy. Řada dalších potenciálně použitelných metod je buď příliš náročná na přístrojové vybavení, jsou příliš invazivní, anebo jsou otestované pouze v experimentu. V blízké budoucnosti však lze v této oblasti medicíny očekávat technologický rozvoj s vývojem nových účinných a bezpečných ochlazovacích systémů.
Induction of mild therapeutic hypothermia early after return of spontaneous circulation improves prognosis of cardiac arrest survivors. Rapid cooling of the patients and correct maintainance of the target therapeutic temperature followed by controlled slow rewarming can be achieved by several noninvasive and invasive methods of various effi cacy. Elementary and the most frequently used methods are surface cooling via ice- packs and rapid intravenous administration of cold crystaloids. Mattress cooling systems and facilities for endovascular cathether- cooling are more sophisticated, manageable and ensure more precise titration of therapeutic temperature. Cooling caps and helmets leading to selective head cooling can be used as the complementary techniques. Several other methods are too instrumentation- intensive, too invasive or investigated in animal experiments only. Anyway, near future may bring a rapid development of new effective and safe cooling systems.
- MeSH
- kardiopulmonální resuscitace MeSH
- lidé MeSH
- srdeční zástava terapie MeSH
- terapeutická hypotermie metody přístrojové vybavení MeSH
- terapeutické zahřívání metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
We have developed an improved technique for fast cooling and heating of solutions superfusing isolated cells under patch-clamp or calcium imaging conditions. The system meets the requirements for studying temperature dependency of all kinds of ion channels, in particular temperature-gated ion channels. It allows the application of temperature changes within a range of 5-60 degrees C at maximum rates of -40 degrees C/s to 60 degrees C/s. Barrels filled with different solutions are connected to a manifold consisting of seven silica capillaries (320 microm inner diameter, i.d.). A common outlet consists of a glass capillary through which the solutions are applied onto the cell surface. The upper part of this capillary is embedded in a temperature exchanger driven by a miniature Peltier device which preconditions the temperature of the passing solution. The lower part of the capillary carries an insulated copper wire, densely coiled over a length of 7 mm, and connected to a dc current source for resistive heating. The Peltier device and the heating element are electrically connected to the headstage probe which is fixed on to a micromanipulator for positioning of the manifold. The temperature of the flowing solution is measured by a miniature thermocouple inserted into the common outlet capillary near to its orifice which is placed at a distance of less than 100 microm from the surface of the examined cell. The temperature is either manually controlled by voltage commands or adjusted via the digital-to-analog converter of a conventional data acquisition interface. Examples are given of using the device in patch-clamp studies on heterologously expressed TRPV1, TRPM8, and on cultured rat sensory neurons.
- MeSH
- akční potenciály fyziologie MeSH
- analýza selhání vybavení MeSH
- buněčné kultury metody přístrojové vybavení MeSH
- design vybavení MeSH
- financování organizované MeSH
- kultivované buňky MeSH
- lidé MeSH
- membránové potenciály fyziologie MeSH
- metoda terčíkového zámku metody přístrojové vybavení MeSH
- neurony aferentní fyziologie MeSH
- nízká teplota MeSH
- perfuze přístrojové vybavení MeSH
- prostředí kontrolované MeSH
- vysoká teplota MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- hodnotící studie MeSH
Over the past decade, fluorescent gold nanoclusters (AuNCs) have witnessed growing popularity in biological applications and enormous efforts have been devoted to their development. In this protocol, a recently developed, facile method for preparation of water soluble, biocompatible, and colloidally stable near-infrared emitting AuNCs have been described in detail. This room-temperature, bottom-up chemical synthesis provides easily functionalizable AuNCs capped with thioctic acid and thiol-modified polyethylene glycol in aqueous solution. The synthetic approach requires neither organic solvents or additional ligand exchange nor extensive knowledge of synthetic chemistry to reproduce. The resulting AuNCs offer free surface carboxylic acids, which can be functionalized with various biological molecules bearing a free amine group without adversely affecting the photoluminescent properties of the AuNCs. A quick, reliable procedure for flow cytometric quantification and confocal microscopic imaging of AuNC uptake by HeLa cells also been described. Due to the large Stokes shift, proper setting of filters in flow cytometry and confocal microscopy is necessary for efficient detection of near-infrared photoluminescence of AuNCs.
- MeSH
- kovové nanočástice chemie MeSH
- lidé MeSH
- zlato chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- audiovizuální média MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
The interactions of epoxiconazole and prothioconazole with human serum albumin and bovine serum albumin were investigated using spectroscopic methods complemented with molecular modeling. Spectroscopic techniques showed the formation of pesticide/serum albumin complexes with the static type as the dominant mechanism. The association constants ranged from 3.80 × 104-6.45 × 105 L/mol depending on the pesticide molecule (epoxiconazole, prothioconazole) and albumin type (human or bovine serum albumin). The calculated thermodynamic parameters revealed that the binding of pesticides into serum albumin macromolecules mainly depended on hydrogen bonds and van der Waals interactions. Synchronous fluorescence spectroscopy and the competitive experiments method showed that pesticides bind to subdomain IIA, near tryptophan; in the case of bovine serum albumin also on the macromolecule surface. Concerning prothioconazole, we observed the existence of an additional binding site at the junction of domains I and III of serum albumin macromolecules. These observations were corroborated well by molecular modeling predictions. The conformation changes in secondary structure were characterized by circular dichroism, three-dimensional fluorescence, and UV/VIS absorption methods.
- MeSH
- cirkulární dichroismus metody MeSH
- epoxidové sloučeniny chemie MeSH
- fluorescenční spektrometrie metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- lidé MeSH
- lidský sérový albumin chemie MeSH
- pesticidy chemie MeSH
- sekundární struktura proteinů MeSH
- sérový albumin hovězí chemie MeSH
- simulace molekulového dockingu metody MeSH
- skot MeSH
- statická elektřina MeSH
- teplota MeSH
- triazoly chemie MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- vodíková vazba MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Three slow growing, melanized and morphologically poorly differentiated fungal strains were isolated from a hyperaemic focus near the enlarged spleen of a farmed rainbow trout (Oncorhynchus mykiss) and from a rock collected at 3,200 m a. s. l. (Alps, Italy). Two phylogenetic analyses of the combined nuc18S and nuc28S rDNA and ITS rDNA and β-tubulin sequences showed that these isolates belong to the Trichomeriaceae, a family of the ascomycete order Chaetothyriales containing black yeasts that cause infections in humans and animals. The strains form a well-supported monophyletic clade. The new genus Bradymyces, with two new species, Bradymyces oncorhynchi and Bradymyces alpinus, is proposed based on phylogenetic, ecophysiological and morphological data. It is characterized by the presence of moniliform hyphae, blastic proliferation, endoconidia, multicellular and muriform bodies, and bodies with dark fragmented incrustations on the surface. Bradymyces most closely resembles members of Knufia. The ex-type isolate of B. oncorhynchi CCF 4369(T) ( = CBS 133066(T) = CCFEE 6134(T)) represents the first case of a Trichomeriaceae member isolated from cold-blooded water vertebrates. B. alpinus [ex-type strain CCFEE 5493(T) ( = CBS 138368(T) = CCF 4803(T))] is represented by two isolates from a single locality in the Alps and in contrast to B. oncorhynchi shows overall slower growth parameters and does not grow at 25 °C.
- MeSH
- Ascomycota klasifikace cytologie genetika izolace a purifikace MeSH
- DNA fungální chemie genetika MeSH
- fylogeneze MeSH
- intergenová DNA chemie genetika MeSH
- mikrobiologie životního prostředí MeSH
- mikroskopie MeSH
- molekulární sekvence - údaje MeSH
- Oncorhynchus mykiss mikrobiologie MeSH
- ribozomální DNA chemie genetika MeSH
- RNA ribozomální 18S genetika MeSH
- RNA ribozomální 28S genetika MeSH
- sekvenční analýza DNA MeSH
- shluková analýza MeSH
- teplota MeSH
- tubulin genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The important task of generating the minimum number of sequential triangle strips (tristrips) for a given triangulated surface model is motivated by applications in computer graphics. This hard combinatorial optimization problem is reduced to the minimum energy problem in Hopfield nets by a linear-size construction. In particular, the classes of equivalent optimal stripifications are mapped one to one to the minimum energy states reached by a Hopfield network during sequential computation starting at the zero initial state. Thus, the underlying Hopfield network powered by simulated annealing (i.e., Boltzmann machine), which is implemented in the program HTGEN, can be used for computing the semioptimal stripifications. Practical experiments confirm that one can obtain much better results using HTGEN than by a leading conventional stripification program FTSG (a reference stripification method not based on neural nets), although the running time of simulated annealing grows rapidly near the global optimum. Nevertheless, HTGEN exhibits empirical linear time complexity when the parameters of simulated annealing (i.e., the initial temperature and the stopping criterion) are fixed and thus provides the semioptimal offline solutions, even for huge models of hundreds of thousands of triangles, within a reasonable time.
The detection of cancer biomarkers in histological samples and blood is of paramount importance for clinical diagnosis. Current methods are limited in terms of sensitivity, hindering early detection of disease. We have overcome the shortcomings of currently available staining and fluorescence labeling methods by taking an integrative approach to establish photon-upconversion nanoparticles (UCNP) as a powerful platform for cancer detection. These nanoparticles are readily synthesized in different sizes to yield efficient and tunable short-wavelength light emission under near-infrared excitation, which eliminates optical background interference of the specimen. Here we present a protocol for the synthesis of UCNPs by high-temperature co-precipitation or seed-mediated growth by thermal decomposition, surface modification by silica or poly(ethylene glycol) that renders the particles resistant to nonspecific binding, and the conjugation of streptavidin or antibodies for biological detection. To detect blood-based biomarkers, we present an upconversion-linked immunosorbent assay for the analog and digital detection of the cancer marker prostate-specific antigen. When applied to immunocytochemistry analysis, UCNPs enable the detection of the breast cancer marker human epidermal growth factor receptor 2 with a signal-to-background ratio 50-fold higher than conventional fluorescent labels. UCNP synthesis takes 4.5 d, the preparation of the antibody-silica-UCNP conjugate takes 3 d, the streptavidin-poly(ethylene glycol)-UCNP conjugate takes 2-3 weeks, upconversion-linked immunosorbent assay takes 2-4 d and immunocytochemistry takes 8-10 h. The procedures can be performed after standard laboratory training in nanomaterials research.
- MeSH
- imunosorbenty MeSH
- lidé MeSH
- nádorové biomarkery MeSH
- nádory * diagnóza MeSH
- nanočástice * chemie MeSH
- oxid křemičitý chemie MeSH
- polyethylenglykoly chemie MeSH
- streptavidin MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
