10 research outputs found
Contemporary Speech of Young People in Russian and Czech Language
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
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
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.
<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.
<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
Caesarean delivery rate and proportion of total cesarean in subgroups of women with births from 28+0 to 44+6 gestational weeks, 2000 to 2010.
<p>Caesarean delivery rate and proportion of total cesarean in subgroups of women with births from 28+0 to 44+6 gestational weeks, 2000 to 2010.</p
Bioinspired Coordination Micelles Integrating High Stability, Triggered Cargo Release, and Magnetic Resonance Imaging
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
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
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