An Introduction to Graphene Materials

Graphene, an allotrope of carbon, is the thinnest compound known to human which is a single layer (monolayer) of carbon atoms, tightly bound in a hexagonal honeycomb lattice. Nanosize graphene is known to possess large surface area and shows promising properties in terms of mechanical, electrical, chemical, and magnetism. Graphene and its derivatives are an exciting replacement for the existing nanomaterials, and so, graphene is discovered to be useful in the application of energy conversion and storage, sensing, electronics, photonics, and biomedicine. In this introductory chapter, the potential implementation of graphene and its nanocomposites, along with the characterization techniques employed for graphene, is briefly discussed. We hope this review can inspire more innovative insights into this emerging topic in energy materials

Synthesis, characterization and effect of pH variation on zinc oxide nanostructures

Here we present a systematic study on the morphological deviation of ZnO nanostructure (from sheets to micro-flowers) by varying pH of the solution via precipitation method. In this regard, zinc nitrate hexa-hydrate, NaOH and hydroxylamine hydrochloride (NH 2 OHÁHCl) were used. The solution of all three compounds was refluxed at a very low temperature (60 C) for short time (20 min). The solution pH was calibrated from 6 to 12 by the controlled addition of NaOH and HCl. We have observed from FESEM (field emission scanning electron microscopy) that the morphology of ZnO microballs composed with thin sheets markedly varies from sheet (at pH ¼ 6) to micro-flower composed with sheets of zinc oxide (pH ¼ 10{12). Further the morphology and crystallinity were also studied by the TEM (transmission electron microscopy) and HR-TEM (High resolution transmission electron microscopy) and it's clearly consistent with the FESEM observations. The FTIR spectroscopic measurement also confirms the compositional analysis of ZnO and it comes in the range of 475 to 424 cm À1 which is a standard peak of ZnO. In addition to this, the amount of H þ and OH À ions are found a key to control the structure of studied material and discussed in the growth mechanism

Formation of ZnO Micro-Flowers Prepared via Solution Process and their Antibacterial Activity

This paper presents the fabrication and characterization of zinc oxide micro-flowers and their antibacterial activity. The micro-flowers of zinc oxide composed of hexagonal nanorods have been prepared via solution process using precursor zinc acetate di-hydrate and sodium hydroxide in 3 h of refluxing time at ~90°C. The antibacterial activities of grown micro-flowers were investigated against four pathogenic bacteria namely S. aureus, E. coli, S. typhimurium and K. pneumoniae by taking five different concentrations (5–45 μg/ml) of ZnO micro-flowers (ZnO-MFs). Our investigation reveals that at lowest concentration of ZnO-MFs solution inhibiting the growth of microbial strain which was found to be 5 μg/ml for all the tested pathogens. Additionally, on the basis of morphological and chemical observations, a chemical reaction mechanism of ZnO-MFs composed of hexagonal nanorods was also proposed

CASS (CyanoAcrylate closure versus Surgical Stripping for incompetent saphenous veins) study: a randomized controlled trial comparing clinical outcomes after cyanoacrylate closure and surgical stripping for the treatment of incompetent saphenous veins

Background Several modalities are used for the treatment of varicose veins. Open surgical treatment with ligation and stripping of the saphenous vein has been the standard of care for many years. Endovenous thermal ablation has been shown to be a safe and effective alternative with high, long-term, target-vein closure rates. Despite this, there is the possibility of thermal injury to surrounding structures. The recently introduced cyanoacrylate closure is also considered to be a good alternative and the risk of injury to surrounding structures is minimal. The purpose of this study is to demonstrate the non-inferiority of cyanoacrylate closure with the VenaSeal™ closure system compared to surgical stripping in terms of clinical outcomes for the treatment of incompetent great saphenous veins. Methods/design This is an open-label, multicenter, prospective, randomized controlled trial evaluating the non-inferior clinical outcomes of cyanoacrylate closure compared to surgical stripping for the treatment of incompetent saphenous veins. After baseline measurements, participants will be randomly allocated into either the cyanoacrylate closure group or the surgical-stripping group. The primary endpoint of the study is the complete closure rate of the target vein in the cyanoacrylate closure group, and the absence of venous reflux or residual venous tissue after surgical stripping in the surgical-stripping group. These endpoints will be measured by Doppler ultrasound performed by qualified vascular technologists or investigators at 3 months after treatment. Secondary outcomes include perioperative pain, postoperative ecchymosis, clinical assessment (including general and disease-specific quality of life evaluations), complete closure rate, and absence of venous reflux or residual venous tissue at the 12- and 24-month follow-ups, as well as all adverse event rates during the 24-month follow-up period. Discussion This multicenter randomized controlled trial is designed to show non-inferiority in terms of complete closure rate of cyanoacrylate compared to surgical stripping for the treatment of incompetent saphenous veins. Trial registration Clinical Research Information Service (CRIS), ID: KCT0003203. Registered on 20 September 2018.This is an investigator-sponsored study supported by a grant from Medtronic Korea Co., Ltd

Protection of nigral dopaminergic neurons by AAV1 transduction with Rheb(S16H) against neurotoxic inflammation in vivo

We recently reported that adeno-associated virus serotype 1 (AAV1) transduction of murine nigral dopaminergic (DA) neurons with constitutively active ras homolog enriched in brain with a mutation of serine to histidine at position 16 [Rheb(S16H)] induced the production of neurotrophic factors, resulting in neuroprotective effects on the nigrostriatal DA system in animal models of Parkinson's disease (PD). To further investigate whether AAV1-Rheb(S16H) transduction has neuroprotective potential against neurotoxic inflammation, which is known to be a potential event related to PD pathogenesis, we examined the effects of Rheb(S16H) expression in nigral DA neurons under a neurotoxic inflammatory environment induced by the endogenous microglial activator prothrombin kringle-2 (pKr-2). Our observations showed that Rheb(S16H) transduction played a role in the neuroprotection of the nigrostriatal DA system against pKr-2-induced neurotoxic inflammation, even though there were similar levels of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1 beta), in the AAV1-Rheb(S16H)-treated substantia nigra (SN) compared to the SN treated with pKr-2 alone; the neuroprotective effects may be mediated by the activation of neurotrophic signaling pathways following Rheb(S16H) transduction of nigral DA neurons. We conclude that AAV1-Rheb(S16H) transduction of neuronal populations to activate the production of neurotrophic factors and intracellular neurotrophic signaling pathways may offer promise for protecting adult neurons from extracellular neurotoxic inflammation.1

Emerging Solar Energy Materials

This book provides the fundamental understanding of the functioning of solar cellsand the materials for the effective utilization of energy resources. The main objective of writing this book is to create a comprehensive and easy-to-understand source of information on the advances in the rapidly growing research on solar cells. Emerging Solar Energy Materials comprises 12 chapters written by the experts in the solar cell field and is organized with the intention to provide a big picture of the latest progress in the solar cell field and at the same time give an in-depth discussion on fundamentals of solar cells for interested audiences. In this book, each part opens with a new author's essay highlighting their work for contribution toward solar energy. Critical, cutting-edge subjects are addressed, including: Photovoltaic device technology and energy applications; Functional solar energy materials; New concept in solar energy; Perovskite solar cells; Dye-sensitized solar cells; Organic solar cells; Thin-film solar cells. The book is written for a large and broad readership including researchers and university graduate students from diverse backgrounds such as chemistry, physics, materials science, and photovoltaic device technology. The book includes enough information on the basics to be used as a textbook undergraduate coursework in engineering and the sciences