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^–1, 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 (CO₂) 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 CO₂ 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 CO₂ in an oil-wet porous medium. The interface between the oil and CO₂ 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 CO₂ in a porous medium. The results show that the pressure in the main CO₂ flow path decreases dramatically after CO₂ breaks through the outlet. Oil begins to reflow into large pores that were previously occupied by CO₂. This phenomenon has an important impact on the final saturation distribution of CO₂. 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 CO₂ is injected into the subsurface. Abnormal high-pressure formations represent a good choice for CO₂ sequestration. Gravity fingers improve the sweep area of CO₂ 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_e 6.5–7.2). An enhanced drug uptake and inhibition of cancer cell proliferation were observed for the tumoral pH_e 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^*.

<p>Inflation adjusted hospitalization cost for ECIC bypass surgery^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186758#t002fn001" target="_blank">*</a>}.</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