Synthesis of Novel Alkaline Polymer Electrolyte for Alkaline Fuel Cell Applicaitons

Development of the intrinsically OH- conductive polymeric electrolyte (alkaline polymer electrolyte, APE) is the critical component to enable the wide application of alkaline fuel cell (AFC) technology. Alkaline polymer electrolyte fuel cell (APEFC) based on AFC technology has been revived recently for applications in transportation and portable electronic devices due to its advantages of using non-noble metal catalysts, faster oxygen reduction in alkaline medium, and compact design. The research described in this dissertation aims to synthesize a novel APE, with controlled ionic conductivity and mechanical strength to achieve high fuel cell power density and long durability. Most APEs synthesized up to now use a modification of existing engineering polymer backbones, which are very difficult to balance its mechanical properties with its ionic conductivities. In this research, we copolymerized APE precursor polymers, namely poly (methyl methacrylate-co-butyl acrylate-co vinylbenzyl chloride) (PMBV) from three functional monomers, methyl methacrylate (MMA), butyl acrylate (BA) and vinylbenzyl chloride (VBC), where VBC was the functional group that was attached with trimethylamine (TMA) and was the OH- carrier after ion-exchanging. MMA was used for mechanical support and BA was used to alleviate the brittleness coming from MMA and VBC. We synthesized alkaline polymer electrolytes from bottom-up polymerization of these selected functional monomers using free radical solution and miniemulsion copolymerization techniques. By miniemulsion copolymerization, the properties of the obtained APEs could be precisely controlled by tuning the (1) monomer ratio, (2) glass transition temperature (Tg), (3) molecular weight (MW), and (4) crosslinking the copolymer. The increase in Tg was realized by eliminating BA from monomers, which was a low Tg component. MW was optimized through investigating binary copolymerization kinetics factors (initiator and surfactant). For crosslinking, the newly obtained poly (methyl methacrylate-co-vinylbenzyl chloride) (PMV) was crosslinked as a semi-interpenetrating network (s-IPN) to reduce water uptake and thus enhanced the mechanical strength in a humidified environment for APEFCs. After the optimization, our best quaternized PMBV (QPMBV) series APE membranes could reach a maximum power density of 180 mW/cm2 and the crosslinked QPMV APE could last 420 hours on APEFCs, which was among the best overall performance in APE technologies. In the future, we propose to use fluorinated polymer monomers to redesign the polymer backbone. Another direction in the design of APEs is to reselect the possible functional OH- carrier groups to make APEs more chemically and mechanically stable in a high pH environment. And last but not least, atomic force spectroscopy (AFM) is proposed to observe the APE nanostructure, the ionic conductive path, and the local mechanical strength by applying a small voltage between the tip and stage

Disinfection efficacy of green synthesized gold nanoparticles for medical disinfection applications

Background: In recent times, biosyntheses of metal nanoparticles were used for several life rescue applications. In this study, Dillenia indica leaf aqueous extract was utilized for the synthesis of gold nanoparticles.Objective: To test anti-microbial properties of biologically fabricated gold nanoparticles.Methods: Gold nanoparticles were efficiently prepared by making use of aqueous leaf extract of Dillenia indica. The excitation of formed AuNPs was confirmed using UV–Vis spectrophotometer. In particular, absorption spectra of AuNPs exhibited a well-defined SPR band centered at around 530 nm.Results: The high-resolution Scanning Electron Microscope (SEM) results of the obtained AuNPs confirmed the formation of particles with a size range of 5–50 nm. The ultra-high resolution TEM (UHRTEM) images displayed clear lattice fringes on the particle surfaces. Single crystalline nature of the biosynthesized AuNPs was represented by means of selected-area electron diffraction pattern.Conclusion: The antibacterial activity of AuNPs revealed significant activity towards both gram negative and gram positive bacteria signifying their potential disinfection related applications in medicine and biology.Keywords: Dillenia indica leaves, disinfection, AuNPs

Disinfection efficacy of green synthesized gold nanoparticles for medical disinfection applications

Background: In recent times, biosyntheses of metal nanoparticles were used for several life rescue applications. In this study, Dillenia indica leaf aqueous extract was utilized for the synthesis of gold nanoparticles. Objective: To test anti-microbial properties of biologically fabricated gold nanoparticles. Methods: Gold nanoparticles were efficiently prepared by making use of aqueous leaf extract of Dillenia indica. The excitation of formed AuNPs was confirmed using UV\u2013Vis spectrophotometer. In particular, absorption spectra of AuNPs exhibited a well-defined SPR band centered at around 530 nm. Results: The high-resolution Scanning Electron Microscope (SEM) results of the obtained AuNPs confirmed the formation of particles with a size range of 5\u201350 nm. The ultra-high resolution TEM (UHRTEM) images displayed clear lattice fringes on the particle surfaces. Single crystalline nature of the biosynthesized AuNPs was represented by means of selected-area electron diffraction pattern. Conclusion: The antibacterial activity of AuNPs revealed significant activity towards both gram negative and gram positive bacteria signifying their potential disinfection related applications in medicine and biology. DOI: https://dx.doi.org/10.4314/ahs.v19i1.17 Cite as: Huang Q, Luo A, Jiang L, Zhou Y, Yang Y, Liu Q, et al. Disinfection efficacy of green synthesized gold nanoparticles for medical disinfection applications. Afri Health Sci. 2019;19(1). 1441-1458. https://dx.doi. org/10.4314/ahs.v19i1.1

An In Vivo Screen Identifies PYGO2 as a Driver for Metastatic Prostate Cancer

Advanced prostate cancer displays conspicuous chromosomal instability and rampant copy number aberrations, yet the identity of functional drivers resident in many amplicons remain elusive. Here, we implemented a functional genomics approach to identify new oncogenes involved in prostate cancer progression. Through integrated analyses of focal amplicons in large prostate cancer genomic and transcriptomic datasets as well as genes upregulated in metastasis, 276 putative oncogenes were enlisted into an in vivo gain-of-function tumorigenesis screen. Among the top positive hits, we conducted an in-depth functional analysis on Pygopus family PHD finger 2 (PYGO2), located in the amplicon at 1q21.3. PYGO2 overexpression enhances primary tumor growth and local invasion to draining lymph nodes. Conversely, PYGO2 depletion inhibits prostate cancer cell invasion in vitro and progression of primary tumor and metastasis in vivo In clinical samples, PYGO2 upregulation associated with higher Gleason score and metastasis to lymph nodes and bone. Silencing PYGO2 expression in patient-derived xenograft models impairs tumor progression. Finally, PYGO2 is necessary to enhance the transcriptional activation in response to ligand-induced Wnt/β-catenin signaling. Together, our results indicate that PYGO2 functions as a driver oncogene in the 1q21.3 amplicon and may serve as a potential prognostic biomarker and therapeutic target for metastatic prostate cancer.Significance: Amplification/overexpression of PYGO2 may serve as a biomarker for prostate cancer progression and metastasis. Cancer Res; 78(14); 3823-33. ©2018 AACR

Effective combinatorial immunotherapy for penile squamous cell carcinoma

Penile squamous cell carcinoma (PSCC) accounts for over 95% of penile malignancies and causes significant mortality and morbidity in developing countries. Molecular mechanisms and therapies of PSCC are understudied, owing to scarcity of laboratory models. Herein, we describe a genetically engineered mouse model of PSCC, by co-deletion of Smad4 and Apc in the androgen-responsive epithelium of the penis. Mouse PSCC fosters an immunosuppressive microenvironment with myeloid-derived suppressor cells (MDSCs) as a dominant population. Preclinical trials in the model demonstrate synergistic efficacy of immune checkpoint blockade with the MDSC-diminishing drugs cabozantinib or celecoxib. A critical clinical problem of PSCC is chemoresistance to cisplatin, which is induced by Pten deficiency on the backdrop of Smad4/Apc co-deletion. Drug screen studies informed by targeted proteomics identify a few potential therapeutic strategies for PSCC. Our studies have established what we believe to be essential resources for studying PSCC biology and developing therapeutic strategies