10 research outputs found

    Contemporary Speech of Young People in Russian and Czech Language

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    Předmětem výzkumu předložené diplomové práce se stala současná mluva mládeže v ruštině a češtině, jazykový útvar značně nestandardní, jehož statut, pojetí a charakter nejsou dosud jednoznačně vymezeny a jednomyslně přijaty. Stěžejní cíle diplomové práce byly zaměřeny na: 1. systematickou strukturně-sémantickou a slovotvornou analýzu slovní zásoby současné mluvy mládeže v ruštině a češtině a zjištění vzájemných spojitostí a rozdílností ve slovní zásobě těchto dvou jazykových útvarů; 2. vytvoření rusko-českého slovníku současné mluvy mládeže, jenž bude představovat výsledek fixace nashromážděného lexikálního materiálu. Powered by TCPDF (www.tcpdf.org

    Organophosphate Esters in Building Materials from China: Levels, Sources, Emissions, and Preliminary Assessment of Human Exposure

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    Source characteristics and health risks of indoor organophosphate esters (OPEs) are limited by the lack of knowledge on emission processes. This study attempted to integrate the contents and emissions of OPEs from indoor building materials to assess human health effects. Thirteen OPEs were investigated in 80 pieces of six categories of building materials. OPEs are ubiquitous in the building materials and ∑13OPE contents varied significantly (p < 0.05) from 72.8 ng/g (seam agent) to 109,900 ng/g (wallpaper). Emission characteristics of OPEs from the building materials were examined based on a microchamber method. Depending on the sample category, the observed initial area-specific emission rates of ∑13OPEs varied from 154 ng/m2/h (carpet) to 2760 ng/m2/h (wooden floorboard). Moreover, the emission rate model was developed to predict the release levels of individual OPEs, quantify source contributions, and assess associated exposure risks. Source apportionments of indoor OPEs exhibited heterogeneities in multiple environmental media. The joint OPE contribution of wallpaper and wooden floorboard to indoor dust was up to 94.8%, while latex paint and wooden floorboard were the main OPE contributors to indoor air (54.2%) and surface (76.1%), respectively. Risk assessment showed that the carcinogenic risks of tris(2-chloroethyl) phosphate (3.35 × 10–7) were close to the acceptable level (1 × 10–6) and deserved special attention

    Stereoselective Stabilization of Polymeric Vitamin E Conjugate Micelles

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    Vitamin E (α-tocopherol; TPGS) micelle is a robust nanocarrier in delivering hydrophobic active pharmaceutical ingredients, but it is suffering from poor stability that is essential in terms of pharmaceutical and biomedical applications. Taking advantage of the chirality of vitamin E, this work reports the stereoselective stabilization of polymer-vitamin E conjugate micelles. Vitamin E was covalently linked to multivalent methoxy poly­(ethylene glycol)-<i>co</i>-poly­(glutamic acid), generating amphiphilic conjugates that could self-assemble into micelles. Eight types of micelles were produced via tailored combination of polymer backbone and side chain with different chirality. The particle size and critical micelle concentration analysis demonstrated a correlation between conjugate chirality and micelle stability. The most stable micelles were obtained when poly­(glutamic acid) and vitamin E both are dextrorotatory, because of the high degree of α-helix revealed by both circular dichroism spectroscopy and molecular dynamics simulation. This phenomenon was further verified by the fluorescence resonance energy transfer (FRET) analysis in HepG2 cells. The current work not only provides a method to enhance the stability of vitamin E micelles, but also adds an additional facile tool in regulating the stability of polymer conjugate micelles without changing the conjugate composition

    The Cesarean Delivery Rate by level of care at the onset of labor (primary or secondary care) among Singleton Births from 28+0 to 44+6 gestational weeks with Vertex Presentation and no Previous Cesarean Delivery, 2000 to 2010.

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    <p>The Cesarean Delivery Rate by level of care at the onset of labor (primary or secondary care) among Singleton Births from 28+0 to 44+6 gestational weeks with Vertex Presentation and no Previous Cesarean Delivery, 2000 to 2010.</p

    Characteristics of obstetric population <sup>a</sup> (including all births, singleton and multiple, from 28+0 to 44+6 gestational weeks), 2000–2010.

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    <p>Characteristics of obstetric population <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155565#t002fn001" target="_blank"><sup>a</sup></a> (including all births, singleton and multiple, from 28+0 to 44+6 gestational weeks), 2000–2010.</p

    Bioinspired Coordination Micelles Integrating High Stability, Triggered Cargo Release, and Magnetic Resonance Imaging

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    Catechol-Fe<sup>3+</sup> coordinated micelles show the potential for achieving on-demand drug delivery and magnetic resonance imaging in a single nanoplatform. Herein, we developed bioinspired coordination-cross-linked amphiphilic polymeric micelles loaded with a model anticancer agent, doxorubicin (Dox). The nanoscale micelles could tolerate substantial dilution to a condition below the critical micelle concentration (9.4 ± 0.3 μg/mL) without sacrificing the nanocarrier integrity due to the catechol-Fe<sup>3+</sup> coordinated core cross-linking. Under acidic conditions (pH 5.0), the release rate of Dox was significantly faster compared to that at pH 7.4 as a consequence of coordination collapse and particle de-cross-linking. The cell viability study in 4T1 cells showed no toxicity regarding placebo cross-linked micelles. The micelles with improved stability showed a dramatically increased Dox accumulation in tumors and hence the enhanced suppression of tumor growth in a 4T1 tumor-bearing mouse model. The presence of Fe<sup>3+</sup> endowed the micelles <i>T</i><sub>1</sub>-weighted MRI capability both in vitro and in vivo without the incorporation of traditional toxic paramagnetic contrast agents. The current work presented a simple “three birds with one stone” approach to engineer the robust theranostic nanomedicine platform

    Alleviating the Liver Toxicity of Chemotherapy via pH-Responsive Hepatoprotective Prodrug Micelles

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    Nanocarriers have been extensively utilized to enhance the anti-tumor performance of chemotherapy, but it is very challenging to eliminate the associated hepatotoxicity. This was due to the significant liver accumulation of cytotoxic drug-loaded nanocarriers as a consequence of systemic biodistribution. To address this, we report a novel type of nanocarrier that was made of hepatoprotective compound (oleanolic acid/OA) with a model drug (methotrexate/MTX) being physically encapsulated. OA was covalently connected with methoxy poly­(ethylene glycol) (mPEG) via a hydrazone linker, generating amphiphilic mPEG–OA prodrug conjugate that could self-assemble into pH-responsive micelles (ca. 100 nm), wherein the MTX loading was ca. 5.1% (w/w). The micelles were stable at pH 7.4 with a critical micelle concentration of 10.5 μM. At the acidic endosome/lysosome microenvironment, the breakdown of hydrazone induced the micelle collapse and fast release of payloads (OA and MTX). OA also showed adjunctive anti-tumor effect with a low potency, which was proved in 4T1 cells. In the mouse 4T1 breasttumor model, MTX-loaded mPEG–OA micelles demonstrated superior capability regarding in vivo tumorgrowth inhibition because of the passive tumor targeting of nanocarriers. Unsurprisingly, MTX induced significant liver toxicity, which was evidenced by the increased liver mass and increased levels of alanine transaminase, aspartate transaminase, and lactate dehydrogenase in serum as well as in liver homogenate. MTX-induced hepatotoxicity was also accompanied with augmented oxidative stress, for example, the increase of the malondialdehyde level and the reduction of glutathione peroxidase and superoxide dismutase concentration in the liver. As expected, mPEG–OA micelles significantly reduced the liver toxicity induced by MTX because of the hepatoprotective action of OA, which was supported by the reversal of all the above biomarkers and qualitative histological analysis of liver tissue. This work offers an efficient approach for reducing the liver toxicity associated with chemotherapy, which can be applied to various antitumor drugs and hepatoprotective materials

    Multifunctional Micelles Dually Responsive to Hypoxia and Singlet Oxygen: Enhanced Photodynamic Therapy via Interactively Triggered Photosensitizer Delivery

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    Nanoparticulate antitumor photodynamic therapy (PDT) has been suffering from the limited dose accumulation in tumor. Herein, we report dually hypoxia- and singlet oxygen-responsive polymeric micelles to efficiently utilize the photosensitizer deposited in the disease site and hence facilely improve PDT’s antitumor efficacy. Tailored methoxy poly­(ethylene glycol)-azobenzene-poly­(aspartic acid) copolymer conjugate with imidazole as the side chains was synthesized. The conjugate micelles (189 ± 19 nm) obtained by self-assembly could efficiently load a model photosensitizer, chlorin e6 (Ce6) with a loading of 4.1 ± 0.5% (w/w). The facilitated cellular uptake of micelles was achieved by the triggered azobenzene collapse that provoked poly­(ethylene glycol) shedding; rapid Ce6 release was enabled by imidazole oxidation that induced micelle disassembly. In addition, the singlet oxygen-mediated cargo release not only addressed the limited diffusion range and short half-life of singlet oxygen but also decreased the oxygen level, which could in turn enhance internalization and increase the intracellular Ce6 concentration. The hypoxia-induced dePEGylation and singlet oxygen-triggered Ce6 release was demonstrated both in aqueous buffer and in Lewis lung carcinoma (LLC) cells. The cellular uptake study demonstrated that the dually responsive micelles could deliver significantly more Ce6 to the cells, which resulted in a substantially improved cytotoxicity. This concurred well with the superior in vivo antitumor ability of micelles in a LLC tumor-bearing mouse model. This study presented an intriguing nanoplatform to realize interactively triggered photosensitizer delivery and improved antitumor PDT efficacy
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