9 research outputs found
Hybrid Polymer Nanoarrays with Bifunctional Conductance of Ions and Electrons and Enhanced Electrochemical Interfaces
Ion
migration and electron transfer are crucial phenomena in electrochemistry
and interfacial sciences, which require effective coupling and integration
of separated charge pathways within medium materials. Here, in this
work, we fabricated an ordered nanowire material based on hybrid polymers
of polypyrrole, with electronic conductance, and perfluorosulfonic
acid ionomers, with ionic conductance, via a facile one-step electrochemical
route. Because of the nanoconfined effects for the different charge-transfer
channels within the nanowire polymer matrix, the electronic and ionic
conductivities of the hybrid polymer are surprisingly enhanced, being
26.4 and 0.096 S cm<sup>–1</sup>, respectively. Such an improvement
in the formation of charge pathways also leads to an increased electrochemical
capacitance through enlargement of the area of ion/electron transport
boundaries, which may show great potential in the applications of
supercapacitors, fuel cells, rechargeable batteries, and other electrochemical
devices
Pore-Scale Investigation of Carbon Dioxide-Enhanced Oil Recovery
Carbon dioxide (CO<sub>2</sub>) enhanced
oil recovery is a green
and promising way to produce oil and reduce the rapid growth of carbon
dioxide released to atmosphere. A pore-scale understanding of CO<sub>2</sub> displacement phenomena is important to enhance oil recovery
in porous media. In this work, a direct numerical simulation method
is employed to investigate the drainage process of CO<sub>2</sub> in
an oil-wet porous medium. The interface between the oil and CO<sub>2</sub> is tracked by the phase field method. The capacity and accuracy
of the model are validated using a classic benchmark: the process
of a bubble rising. A series of numerical experiments were performed
over a large range of values of the gravity number, capillary number,
and viscosity ratio to investigate the flooding process of CO<sub>2</sub> in a porous medium. The results show that the pressure in
the main CO<sub>2</sub> flow path decreases dramatically after CO<sub>2</sub> breaks through the outlet. Oil begins to reflow into large
pores that were previously occupied by CO<sub>2</sub>. This phenomenon
has an important impact on the final saturation distribution of CO<sub>2</sub>. Increasing the viscous force is the dominant mechanism for
improving oil recovery. Selecting an appropriate depth is the primary
consideration for reaching the maximum recovery before CO<sub>2</sub> is injected into the subsurface. Abnormal high-pressure formations
represent a good choice for CO<sub>2</sub> sequestration. Gravity
fingers improve the sweep area of CO<sub>2</sub> when the viscous
force is small. The oil recovery increases with increasing contact
angle. It is difficult to reach the final steady state of saturation
because of the “snap-off and supplement” dynamic balance
in porous media when both the injection velocity and the contact angle
are small
pH-Triggered Charge-Reversal Polypeptide Nanoparticles for Cisplatin Delivery: Preparation and In Vitro Evaluation
A series of pH-responsive random
copolymer poly(l-glutamic
acid-<i>co</i>-l-lysine) [P(Glu-<i>co</i>-Lys)] were synthesized through the ring-opening polymerization (ROP)
of γ-benzyl-l-glutamate <i>N</i>-carboxyanhydride
(BLG-NCA) and 3-benzyloxycarbonyl-l-lysine <i>N</i>-carboxyanhydride (ZLys-NCA) and the subsequent deprotection. The
chemical structure of the P(Glu-<i>co</i>-Lys)s was confirmed
by NMR. Critical aggregation concentration and transmission electron
microscopy measurements indicated that the P(Glu-<i>co</i>-Lys)s could self-assemble into aggregates in phosphate buffer. The
surface charge of P(Glu-<i>co</i>-Lys) aggregates was greatly
affected by the solution’s pH and l-glutamic acid/l-lysine ratio because the carboxyl and amino groups present
on the P(Glu-<i>co</i>-Lys) aggregates could be protonated
or deprotonated to become charged. The pH value of the solution at
which the surface charge of the P(Glu-<i>co</i>-Lys) aggregates
reversed could be manipulated by the feed ratio of BLG-NCA and ZLys-NCA.
In vitro methyl thiazolyl tetrazolium assays demonstrated that negatively
charged P(Glu-<i>co</i>-Lys)s were nontoxic and biocompatible.
Positive charged P(Glu-<i>co</i>-Lys)s showed some cytotoxicity
to Hela cells. Cisplatin (CDDP) was used as a model anticancer drug
to evaluate the charge-reversal drug delivery system. By the manipulation
of CDDP loading content, the surface charge of the CDDP/P(Glu-<i>co</i>-Lys) nanoparticles could be reversed to positive from
negative at tumor extracellular pH (pH<sub>e</sub> 6.5–7.2).
An enhanced drug uptake and inhibition of cancer cell proliferation
were observed for the tumoral pH<sub>e</sub> triggered charge-reversal
CDDP/P(Glu-<i>co</i>-Lys) drug delivery system. These indicated
that the CDDP/P(Glu-<i>co</i>-Lys) nanoparticles could be
used as intelligent drug delivery systems for cancer therapy
Nanoscaled Poly(l‑glutamic acid)/Doxorubicin-Amphiphile Complex as pH-responsive Drug Delivery System for Effective Treatment of Nonsmall Cell Lung Cancer
Nonsmall cell lung cancer (NSCLC)
is the leading cause of cancer-related death worldwide. Herein, we
develop a polypeptide-based block ionomer complex formed by anionic
methoxy poly(ethylene glycol)-<i>b</i>-poly(l-glutamic
acid) (mPEG-<i>b</i>-PLG) and cationic anticancer drug doxorubicin
hydrochloride (DOX·HCl) for NSCLC treatment. This complex spontaneously
self-assembled into spherical nanoparticles (NPs) in aqueous solutions
via electrostatic interaction and hydrophobic stack, with a high loading
efficiency (almost 100%) and negative surface charge. DOX·HCl
release from the drug-loaded micellar nanoparticles (mPEG-<i>b</i>-PLG-DOX·HCl) was slow at physiological pH, but obviously
increased at the acidic pH mimicking the endosomal/lysosomal environment.
In vitro cytotoxicity and hemolysis assays demonstrated that the block
copolypeptide was cytocompatible and hemocompatible, and the presence
of copolypeptide carrier could reduce the hemolysis ratio of DOX·HCl
significantly. Cellular uptake and cytotoxicity studies suggested
that mPEG-<i>b</i>-PLG-DOX·HCl was taken up by A549
cells via endocytosis, with a slightly slower cellular internalization
and lower cytotoxicity compared with free DOX·HCl. The pharmacokinetics
study in rats showed that DOX·HCl-loaded micellar NPs significantly
prolonged the blood circulation time. Moreover, mPEG-<i>b</i>-PLG-DOX·HCl exhibited enhanced therapeutic efficacy, increased
apoptosis in tumor tissues, and reduced systemic toxicity in nude
mice bearing A549 lung cancer xenograft compared with free DOX·HCl,
which were further confirmed by histological and immunohistochemical
analyses. The results demonstrated that mPEG-<i>b</i>-PLG
was a promising vector to deliver DOX·HCl into tumors and achieve
improved pharmacokinetics, biodistribution and efficacy of DOX·HCl
with reduced toxicity. These features strongly supported the interest
of developing mPEG-<i>b</i>-PLG-DOX·HCl as a valid
therapeutic modality in the therapy of human NSCLC and other solid
tumors
Inflation adjusted hospitalization cost for ECIC bypass surgery<sup>*</sup>.
<p>Inflation adjusted hospitalization cost for ECIC bypass surgery<sup><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186758#t002fn001" target="_blank">*</a></sup>.</p
Demographic and clinical characteristics of 1,533 patients registered in the NIS that underwent EC-IC bypass surgery across 218 non-federal hospitals between 2002 and 2011.
<p>Demographic and clinical characteristics of 1,533 patients registered in the NIS that underwent EC-IC bypass surgery across 218 non-federal hospitals between 2002 and 2011.</p
Percent change in hospitalization cost following EC-IC bypass surgery for the variables included in the final predictive model.
<p>Percent change in hospitalization cost following EC-IC bypass surgery for the variables included in the final predictive model.</p
Algorithm for cohort selection for patients undergoing EC-IC bypass.
<p>Algorithm for cohort selection for patients undergoing EC-IC bypass.</p
Cohort definition and extraction
The figure describes the ICD-9 coding definitions along with the inclusion and exclusion criteria's that were utilized to establish a cohort of patients registered in the Nationwide Inpatient Sample database [2002-2011] that underwent extracranial-intracranial (EC-IC) bypass surgery for various indications