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1.
Chemosphere ; 350: 141053, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38154669

ABSTRACT

This work reports the development of multifunctional or polymorphous surfaces using zinc oxide (ZnO) nanorods, silica (SiO2), and fluoropolymer functionalization in a sequential process. Firstly, zinc oxide nanorods were grown on activated carbon cloth (ACC) using a simple low-temperature synthesis process. ZnO nanorods-coated ACC substrate was applied to investigate the antimicrobial properties, and the results showed inhibition of 50% for Escherichia coli (E.coli) and 55% for Bacillus subtilis (B.subtilis) over 48 h of incubation time. Subsequent in-situ modification of silica nanoparticles like layer on ZnO nanorods-coated ACC surface was developed and used as an electrode for brackish water desalination in a capacitive deionization system. ZnO-SiO2 modified ACC surface enhanced the desalination efficiency by 1.6 times, the salt removal rate (SRR) by threefold, and the durability (fouling prevention) for long-term usage compared to pristine ACC. Further modification of the ZnO-SiO2-ACC surface using fluoropolymer rendered the surface superhydrophobic and oleophilic. Vegetable (1.4 g/g) and crude oil (1.6 g/g) adsorption capacities were achieved for modified surface which was 70% enhancement compared with pristine ACC. The dynamic oil spill adsorption test exhibited the complete removal of oil spills on water surfaces within a few seconds, suggesting a potential application in oil spill cleaning.


Subject(s)
Nanotubes , Petroleum Pollution , Zinc Oxide , Charcoal , Zinc Oxide/chemistry , Fluorocarbon Polymers , Silicon Dioxide , Anti-Bacterial Agents/pharmacology , Nanotubes/chemistry
2.
Harm Reduct J ; 20(1): 164, 2023 11 02.
Article in English | MEDLINE | ID: mdl-37919736

ABSTRACT

BACKGROUND: In Kenya, violence is common among people who inject drugs (PWID) living with HIV and their sexual and injecting partners and may lead to decreased uptake of HIV services, increased HIV risk behaviors, and increased HIV transmission. Violence is defined as any physical harm, threatened harm, or forced sexual acts inflicted on a person in the past year. Understanding the nature of violence and its correlates among PWID and their partners will inform population-specific public health interventions and policy recommendations. METHODS: This is a cross-sectional study nested in a prospective cohort study conducted in eight public health centers, methadone clinics, and needle syringe programs in Nairobi, Kilifi, and Mombasa counties in Kenya. 3,302 sexual and/or injecting partners of PWID living with HIV were recruited through assisted partner services and participated in the study. Prevalence and correlates of violence were identified using the Wald test and negative binomial regression. RESULTS: Out of 3302 study participants, 1439 (44%) had experienced violence within the past year. Physical violence was the most common form of violence experienced (35%), followed by being threatened (23%) or subjected to sexual violence (7%). In an adjusted analysis, female participants reported higher experiences of sexual violence (prevalence ratio [PR] = 2.46; 95% confidence interval [CI] 1.62, 3.74; p < 0.001) compared to male participants. In adjusted analysis, coastal residents had a higher experience of overall violence (PR = 1.48; 95% CI 1.27, 1.72; p < 0.001) than those living in Nairobi. This regional effect was relatively stronger among the female respondents (pinteraction = 0.025). Participants' sex modified the association between region and experiencing violence after adjusting potential confounding factors. CONCLUSIONS: The study reveals the prevalence of violence among PWID and identifies high-risk sub-groups, including women, specifically for sexual violence, and coastal residents. Tailored interventions addressing their unique needs are essential. A holistic approach that combines violence prevention and response, comprehensive harm reduction, healthcare access, and community support is crucial to address the complex issue of drug use and HIV burden among PWID in Kenya for improved health outcomes.


Subject(s)
Drug Users , HIV Infections , Substance Abuse, Intravenous , Male , Humans , Female , Cross-Sectional Studies , Substance Abuse, Intravenous/epidemiology , Prevalence , Kenya/epidemiology , Prospective Studies , HIV Infections/epidemiology , Violence , Sexual Partners
3.
Discov Nano ; 18(1): 45, 2023 Mar 18.
Article in English | MEDLINE | ID: mdl-37382758

ABSTRACT

In this study, systematic development of a portable sensor for the rapid detection of Escherichia coli (E. coli) and Exiguobacterium aurantiacum (E. aurantiacum) was reported. A conductive glass was utilized as a substrate and developed the electrode patterns on it. Trisodium citrate (TSC) and chitosan-stabilized gold nanoparticles (AuNPs) (CHI-AuNP-TSC) and chitosan-stabilized AuNPs (CHI-AuNP) were synthesized and utilized as a sensing interface. The morphology, crystallinity, optical properties, chemical structures, and surface properties of immobilized AuNPs on the sensing electrodes were investigated. The sensing performance of the fabricated sensor was evaluated by using an electrochemical method to observe the current changes in cyclic voltammetric responses. The CHI-AuNP-TSC electrode has higher sensitivity toward E. coli than CHI-AuNP with a limit of detection (LOD) of 1.07 CFU/mL. TSC in the AuNPs synthesis process played a vital role in the particle size, the interparticle spacing, the sensor's effective surface area, and the presence of CHI around AuNPs, thus enhancing the sensing performance. Moreover, post-analysis of the fabricated sensor surface exhibited the sensor stability and the interaction between bacteria and the sensor surface. The sensing results showed a promising potential for rapid detection using a portable sensor for various water and food-borne pathogenic diseases.

4.
Nanomaterials (Basel) ; 12(21)2022 Oct 24.
Article in English | MEDLINE | ID: mdl-36364511

ABSTRACT

The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications.

5.
Materials (Basel) ; 15(17)2022 Aug 24.
Article in English | MEDLINE | ID: mdl-36079209

ABSTRACT

This study investigates the growth time effect on the structural, morphological, optical, and photoelectrochemical characteristics of highly oriented ZnO nanorod arrays (ZNRAs). The nanorod arrays were grown on ITO substrates using the unified sol-gel spin coating and hydrothermal techniques. ZnO nanoparticles (ZNPs) were synthesized using the sol-gel spin coating method. In contrast, the hydrothermal method was used to grow the ZnO nanorods. The hydrothermal growth time investigated was between 4 and 12 h. The synthesized ZNRAs were used as the photoanode electrodes to investigate their photoelectrochemical (PEC) electrode potency. The as-prepared ZNRAs were characterized using various analytical tools to determine their structures, morphologies, optical, and photoelectrochemical traits. EDX spectra showed the presence of uncontaminated ZnO chemical composition, and FTIR spectra displayed the various functional groups in the samples. A rod-shaped ZnO nanocrystallite with mean lengths and diameters of 300-500 nm and 40-90 nm, respectively, is depicted. HRTEM images indicated the nucleation and growth of ZNRAs with a lattice fringe spacing of 0.26 nm and a growth lattice planer orientation of [002]. The optimum ZNRAs (grown at 8 h) as photoelectrode achieved a photoconversion efficiency of 0.46% and photocurrent density of 0.63 mA/cm2, that was 17 times higher than the one shown by ZNPs with Ag/AgCl as the reference electrode. Both values were higher than those reported in the literature, indicating the prospect of these ZNRAs for photoelectrode applications.

6.
Membranes (Basel) ; 12(7)2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35877874

ABSTRACT

The Barka desalination plant, commissioned in 2018, is the largest desalination plant in Oman. It has a capacity of 281 MLD with a reverse osmosis (RO) first-pass recovery rate of 46%. As part of the standard operator practice, a membrane autopsy was conducted to determine the cause of reductions in membrane performance. This study investigated fouled membranes (model No. SW30HRLE-440) from two different locations in the membrane rack. Various analytical methods were used to conduct the membrane autopsy. Field-emission scanning electron microscopy/energy-dispersive X-ray (FESEM/EDS) analyses of membrane samples showed major components of inorganic foulants. Moreover, black and salt-like crystals deposited on the membrane surface revealed significant carbon (C) components and oxygen (O), with a small amount of magnesium (Mg), chloride (Cl), sodium (Na), aluminium (Al), and calcium (Ca), respectively. A Fourier transform infrared (FTIR) analysis revealed the presence of long-chain hydrocarbons, carboxylic acids/esters, carbohydrates/polysaccharides, and inorganic foulants. Thermogravimetric analyses (TGA) of the membranes showed a high initial weight loss due to organic and inorganic fouling. X-ray photoelectron (XPS) analyses further confirmed the presence of inorganic and organic foulants on the membrane surfaces. Bacteria identification results showed the presence of Bacillus cereus and Bacillus marisflavi. This paper offers a detailed analysis of the foulants present on the reverse osmosis membrane surface and sub-surface before and after a cleaning process.

7.
J Environ Manage ; 304: 114319, 2022 Feb 15.
Article in English | MEDLINE | ID: mdl-35021592

ABSTRACT

Prunus Armeniaca seed (PAS) oil was utilised as a waste biomass feedstock for biodiesel production via a novel catalytic system (SrO-La2O3) based on different stoichiometric ratios. The catalysts have been characterised and followed by a parametric analysis to optimise catalyst results. The catalyst with a stoichiometric ratio of Sr: La-8 (Sr-La-C) using parametric analysis showed an optimum yield of methyl esters is 97.28% at 65 °C, reaction time 75 min, catalyst loading 3 wt% and methanol to oil molar ratio of 9. The optimum catalyst was tested using various oil feedstocks such as waste cooking oil, sunflower oil, PAS oil, date seed oil and animal fat. The life cycle assessment was performed to evaluate the environmental impacts of biodiesel production utilising waste PAS, considering 1000 kg of biodiesel produced as 1 functional unit. The recorded results showed the cumulative abiotic depletion of fossil resources over the entire biodiesel production process as 22,920 MJ, global warming potential as 1150 kg CO2 equivalent, acidification potential as 4.89 kg SO2 equivalent and eutrophication potential as 0.2 kg PO43- equivalent for 1 tonne (1000 kg) of biodiesel produced. Furthermore, the energy ratio (measured as output energy divided by input energy) for the entire production process was 1.97. These results demonstrated that biodiesel obtained from the valorisation of waste PAS provides a suitable alternative to fossil fuels.


Subject(s)
Biofuels , Prunus armeniaca , Animals , Catalysis , Life Cycle Stages , Plant Oils
8.
Microbiol Resour Announc ; 10(4)2021 Jan 28.
Article in English | MEDLINE | ID: mdl-33509989

ABSTRACT

Here, we report the complete genome sequences of three Ralstonia solanacearum strains isolated from Zingiberaceae plants in Japan. The total genome sizes of these strains ranged from 5.87 to 6.05 Mb. Strains MAFF 211472, MAFF 211479, and MAFF 311693 each carried one chromosome and one megaplasmid. MAFF 311693 contained an additional 71.9-kb plasmid.

9.
Materials (Basel) ; 13(19)2020 Oct 05.
Article in English | MEDLINE | ID: mdl-33027934

ABSTRACT

The development of durable photocatalytic supports resistant in harsh environment has become challenging in advanced oxidation processes (AOPs) focusing on water and wastewater remediation. In this study, stainless steel (SS), SS/Ti (N,O) and SS/Cr-N/Cr (N,O) anticorrosion layers on SS meshes were dip-coated with sol gel synthesised C-N-TiO2 photo catalysts pyrolysed at 350 °C for 105 min, using a heating rate of 50 °C/min under N2 gas. The supported C-N-TiO2 films were characterised by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. The results showed that C-N-TiO2 was successfully deposited on anticorrosion coated SS supports and had different morphologies. The amorphous C and TiO2 were predominant in C-N-TiO2 over anatase and rutile phases on the surface of SS and anticorrosion supports. The C-N-TiO2 coated films showed enhanced photocatalytic activity for the decolouration of O.II dye under both solar and UV radiation. The fabricated C-N-TiO2 films showed significant antibacterial activities in the dark as well as in visible light. Herein, we demonstrate that SS/Ti(N,O) and SS/Cr-N/Cr(N,O) anticorrosion coatings are adequate photocatalytic and corrosion resistant supports. The C-N-TiO2 photo catalytic coatings can be used for water and wastewater decontamination of pollutants and microbes.

10.
Nanoscale Res Lett ; 15(1): 192, 2020 Oct 01.
Article in English | MEDLINE | ID: mdl-33001332

ABSTRACT

Doped magnetite (SnxFe3-2/3xO4) nanoparticles (NPs) (12-50 nm) with different amount of Sn2+ ions (x) were synthesized using co-precipitation method. Sn2+ doping reduces the anticipated oxidation of Fe3O4 NPs to maghemite (γ-Fe2O3), making them attractive in several magnetic applications. Detailed characterizations during heating-cooling cycles revealed the possibility of tuning the unusual observed magnetization dipping temperature/amplitude, irreversibility, and Curie point of these NPs. We attribute this dip to the chemical reduction of γ-Fe2O3 at the NPs surfaces. Along with an increase in the dipping temperature, we found that doping with Sn2+ reduces the dipping amplitude, until it approximately disappears when x = 0.150. Based on the core-shell structure of these NPs, a phenomenological expression that combines both modified Bloch law (M = M0[1 - γ(T/TC)]ß) and a modified Curie-Weiss law (M = - α[1/(T - TC)δ]) is developed in order to explain the observed M-T behavior at different applied external magnetic fields and for different Sn2+ concentrations. By applying high enough magnetic field, the value of the parameters γ and δ ≈ 1 which are the same in modified Bloch and Curie-Weiss laws. They do not change with the magnetic field and depend only on the material structure and size. The power ß for high magnetic field was 2.6 which is as expected for this size of nanoparticles with the core dominated magnetization. However, the ß value fluctuates between 3 and 10 for small magnetic fields indicating an extra magnetic contribution from the shell structure presented by Curie-Weiss term. The parameter (α) has a very small value and it turns to negative values for high magnetic fields.

11.
Int J Biol Macromol ; 162: 1743-1751, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32800955

ABSTRACT

The current study describes the fabrication of chitosan­zinc oxide nanorods composite (CHT/ZnO) on fiberglass panels (support substrate). ZnO nanorods (NRs) with size ranging from 20 to 100 nm and some microrods with an approximate size of 0.5-1 µm were grown on fiberglass panels. CHT 1%/ZnO composite had ZnO NRs incorporated into chitosan (CHT) coating while ZnO NRs were not visible in the CHT 2%/ZnO NRs composite. XRD and FTIR results showed the presence of the ZnO and chitosan. The water contact angle decreased from 80° ± 2° (control) to 65° ± 2° for CHT 1%/ZnO NRs and 42 ± 2° for CHT 2%/ZnO NRs composite coatings. The antimicrobial activities of the coated fiberglass panels were investigated using biofilm-forming bacteria Bacillus subtilis and Escherichia coli under both light and dark conditions. CHT/ZnO composite coated fiberglass panels showed the strongest antimicrobial activity compared to chitosan, ZnO NRs coatings, and Zn-based antifouling paint in the experiments with B. subtilis and E. coli under light conditions. The highest antifouling activity was observed for CHT 2%/ZnO composites. CHT/ZnO composites can be good alternatives to the toxic antifouling paints.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Chitosan/pharmacology , Nanocomposites/chemistry , Nanotubes/chemistry , Zinc Oxide/pharmacology , Bacillus subtilis/drug effects , Bacillus subtilis/physiology , Escherichia coli/drug effects , Escherichia coli/physiology
12.
J Hazard Mater ; 385: 121565, 2020 03 05.
Article in English | MEDLINE | ID: mdl-31732340

ABSTRACT

Activated carbon cloth (ACC) coated with zinc oxide (ZnO) nanoparticles (NPs) have been used as electrodes in flow-by capacitive deionization (CDI) system. Aqueous solution of individual Pb2+ and Cd2+ ions and mixed Pb2+ and Cd2+ ions were used as test contaminant in CDI system to study the effect of surface modification upon ions removal efficiency. Due to the aggregated structure of ZnO NPs on ACC surface, the modified ACC electrodes develop the additional surface area as well as dielectric barrier therefore resulting in higher specific capacitance. In addition, coating with ZnO NPs effectively reduced physical adsorption whereby enhanced the ions adsorption rate and capacity during electrosorption process. Upon incorporating with ZnO NPs, the electrosorption efficiency was enhanced from 17% to 33% for Pb2+, from 21% to 29% for Cd2+ and from 21% to 35% for mixed Pb2+ and Cd2+ ions. The power consumption of individual ions and mixed ions removal process for ACC and ZnO NPs modified ACC were also discussed. Furthermore, used ACC electrodes surfaces were examined using photoelectron spectroscopy (XPS) and results were also conferred. The CDI ACC electrodes with ZnO NPs showed a promising and an effective way for heavy metal removal applications.

13.
Zootaxa ; 4238(4): 571-582, 2017 Mar 06.
Article in English | MEDLINE | ID: mdl-28603251

ABSTRACT

A newly discovered species of homalopsid snake from the genus Gyiophis Murphy & Voris is described from the lowlands of Mawlamyine District in Mon state, southeastern Myanmar. Gyiophis salweenensis sp. nov. is presumed to be closely related to G. maculosa Blanford and G. vorisi Murphy based on the similarities in pholidosis and patterning but can be separated from G. maculosa by the shape of its first three dorsal scale rows that are square, ventral scale pattern that lacks a central spot, and a faint stripe on dorsal scale rows 1-4. It can be further distinguished from G. vorisi by its lower number of ventral scales (129 vs. 142-152), lower number of subcaudals (30/29 vs. 41-58), narrow rostral scale, and having more rows of spots on the dorsum (four vs. three). A preliminary molecular analysis using 1050 base pairs of cytochrome b (cytb) recovered G. salweenensis sp. nov. as the sister species to the Chinese Mud Snake (Myrrophis chinensis). G. maculosa and G. vorisi were unavailable for the analysis. The discovery of G. salweenensis sp. nov. highlights the need for more surveys into the herpetological diversity of eastern Myanmar which remains very much underestimated.


Subject(s)
Colubridae , Animals , Ecosystem , Myanmar , Phylogeny
14.
PLoS One ; 12(5): e0176364, 2017.
Article in English | MEDLINE | ID: mdl-28520726

ABSTRACT

New and rapid political and economic changes in Myanmar are increasing the pressures on the country's forests. Yet, little is known about the past and current condition of these forests and how fast they are declining. We mapped forest cover in Myanmar through a consortium of international organizations and environmental non-governmental groups, using freely-available public domain data and open source software tools. We used Landsat satellite imagery to assess the condition and spatial distribution of Myanmar's intact and degraded forests with special focus on changes in intact forest between 2002 and 2014. We found that forests cover 42,365,729 ha or 63% of Myanmar, making it one of the most forested countries in the region. However, severe logging, expanding plantations, and degradation pose increasing threats. Only 38% of the country's forests can be considered intact with canopy cover >80%. Between 2002 and 2014, intact forests declined at a rate of 0.94% annually, totaling more than 2 million ha forest loss. Losses can be extremely high locally and we identified 9 townships as forest conversion hotspots. We also delineated 13 large (>100,000 ha) and contiguous intact forest landscapes, which are dispersed across Myanmar. The Northern Forest Complex supports four of these landscapes, totaling over 6.1 million ha of intact forest, followed by the Southern Forest Complex with three landscapes, comprising 1.5 million ha. These remaining contiguous forest landscape should have high priority for protection. Our project demonstrates how open source data and software can be used to develop and share critical information on forests when such data are not readily available elsewhere. We provide all data, code, and outputs freely via the internet at (for scripts: https://bitbucket.org/rsbiodiv/; for the data: http://geonode.themimu.info/layers/geonode%3Amyan_lvl2_smoothed_dec2015_resamp).


Subject(s)
Conservation of Natural Resources , Forests , Myanmar , Satellite Imagery , Trees/physiology
15.
J Biol Chem ; 292(26): 10855-10864, 2017 06 30.
Article in English | MEDLINE | ID: mdl-28533434

ABSTRACT

The lysophosphatidylinositol (LPI) has crucial roles in multiple physiological processes, including insulin exocytosis from pancreatic islets. However, the role of LPI in secretion of glucagon-like peptide-1 (GLP-1), a hormone that enhances glucose-induced insulin secretion, is unclear. Here, we used the murine enteroendocrine L cell line GLUTag and primary murine small intestinal cells to elucidate the mechanism of LPI-induced GLP-1 secretion. Exogenous LPI addition increased intracellular Ca2+ concentrations ([Ca2+] i ) in GLUTag cells and induced GLP-1 secretion from both GLUTag and acutely prepared primary intestinal cells. The [Ca2+] i increase was suppressed by an antagonist for G protein-coupled receptor 55 (GPR55) and by silencing of GPR55 expression, indicating involvement of Gq and G12/13 signaling pathways in the LPI-induced increased [Ca2+] i levels and GLP-1 secretion. However, GPR55 agonists did not mimic many of the effects of LPI. We also found that phospholipase C inhibitor and Rho-associated kinase inhibitor suppressed the [Ca2+] i increase and that LPI increased the number of focal adhesions, indicating actin reorganization. Of note, blockage or silencing of transient receptor potential cation channel subfamily V member 2 (TRPV2) channels suppressed both the LPI-induced [Ca2+] i increase and GLP-1 secretion. Furthermore, LPI accelerated TRPV2 translocation to the plasma membrane, which was significantly suppressed by a GPR55 antagonist. These findings suggest that TRPV2 activation via actin reorganization induced by Gq and G12/13 signaling is involved in LPI-stimulated GLP-1 secretion in enteroendocrine L cells. Because GPR55 agonists largely failed to mimic the effects of LPI, its actions on L cells are at least partially independent of GPR55 activation.


Subject(s)
Calcium Channels/metabolism , Calcium Signaling/physiology , Enteroendocrine Cells/metabolism , Glucagon-Like Peptide 1/metabolism , Lysophospholipids/metabolism , TRPV Cation Channels/metabolism , Animals , Calcium Channels/genetics , Cells, Cultured , Focal Adhesions/genetics , Focal Adhesions/metabolism , GTP-Binding Protein alpha Subunits/genetics , GTP-Binding Protein alpha Subunits/metabolism , Glucagon-Like Peptide 1/genetics , Mice , Protein Transport/physiology , Receptors, Cannabinoid/genetics , Receptors, Cannabinoid/metabolism , TRPV Cation Channels/genetics
16.
Sci Rep ; 7: 41093, 2017 01 23.
Article in English | MEDLINE | ID: mdl-28112215

ABSTRACT

Drug-induced hepatotoxicity is one of the major reasons cited for drug withdrawal. Therefore, it is of extreme importance to detect human hepatotoxic candidates as early as possible during the drug development process. In this study, we aimed to enhance hepatocyte functions such as CYP gene expression in HepG2 cells, one of the most extensively used cell lines in evaluating hepatotoxicity of chemicals and drugs. We found that zebularine, a potent inhibitor of DNA methylation, remarkably upregulates the expression of CYP genes in HepG2 cells. In addition, we revealed that the upregulation of CYP gene expression by zebularine was mediated through the inhibition of both DNA methyltransferase 1 (DNMT1) and double-stranded RNA-dependent protein kinase (PKR). Furthermore, HepG2 cells treated with zebularine were more sensitive than control cells to drug toxicity. Taken together, our results show that zebularine may make HepG2 cells high-functioning and thus could be useful for evaluating the hepatotoxicity of chemicals and drugs speedily and accurately in in-vitro systems. The finding that zebularine upregulates CYP gene expression through DNMT1 and PKR modulation sheds light on the mechanisms controlling hepatocyte function and thus may aid in the development of new in-vitro systems using high-functioning hepatocytes.


Subject(s)
Cyclophilins/genetics , Cytidine/analogs & derivatives , DNA (Cytosine-5-)-Methyltransferase 1/genetics , eIF-2 Kinase/genetics , Apoptosis/drug effects , Cytidine/pharmacology , DNA Methylation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Hep G2 Cells , Hepatocytes/drug effects , Humans
17.
Nanoscale Res Lett ; 12(1): 22, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28063141

ABSTRACT

We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular H2O within the structure of the NRs. In the absence of H2O, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of H2O, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (~1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of H2O/H* species.

18.
Biol Pharm Bull ; 38(8): 1109-12, 2015.
Article in English | MEDLINE | ID: mdl-26235574

ABSTRACT

Environmental influences, such as chemical exposure, have long been considered potential risk factors for neurodegenerative disorders, including neuromuscular diseases. However, no definitive links between environmental chemical exposure and a pathogenic mechanism of neurodegenerative disease has yet been established. In this study, we describe that exposure to arsenic, an environmental pollutant naturally found in drinking water, induces neuronal cell death and alteration of morphology, particularly neurite outgrowth and in the cytoskeleton of neurons. Since progressive cell loss accompanied by the alteration of neuronal structures and cytoskeleton is considered the major pathologic feature of neurodegenerative disorders, arsenic-induced neurotoxicity might contribute to an etiologic mechanism of some neurodegenerative diseases. Further, we discuss the importance of in vitro assay, particularly an embryonic toxicity test, for assessing the neurotoxicity of chemicals, because most of chemicals found in our environment remain to be evaluated regarding their neurotoxicity risk for neurodegenerative diseases.


Subject(s)
Arsenic/adverse effects , Cell Death , Cytoskeleton/pathology , Environmental Pollutants/adverse effects , Neurodegenerative Diseases/etiology , Neurons/pathology , Neurotoxicity Syndromes/complications , Animals , Cells, Cultured , Humans , Neurites , Neurodegenerative Diseases/pathology
19.
Beilstein J Nanotechnol ; 6: 2345-53, 2015.
Article in English | MEDLINE | ID: mdl-26734526

ABSTRACT

The self-organization of monolayer gold nanoparticles (AuNPs) on 3-aminopropyltriethoxysilane (APTES)-functionalized glass substrate is reported. The orientation of APTES molecules on glass substrates plays an important role in the interaction between AuNPs and APTES molecules on the glass substrates. Different orientations of APTES affect the self-organization of AuNps on APTES-functionalized glass substrates. The as grown monolayers and films annealed in ultrahigh vacuum and air (600 °C) were studied by water contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, UV-visible spectroscopy and ultraviolet photoelectron spectroscopy. Results of this study are fundamentally important and also can be applied for designing and modelling of surface plasmon resonance based sensor applications.

20.
J Toxicol Sci ; 39(2): 217-29, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24646702

ABSTRACT

A widely-used plasticizer di(2-ethylhexyl) phthalate (DEHP) is known to induce apoptosis in neurons, although the mechanisms responsible for DEHP-induced apoptosis is not well explored yet. We recently showed that exposure to DEHP increases the expression of hemeoxygenase (HO)-1, an oxidative stress related enzyme, in the mice brain. In this study, we investigated whether HO-1 is involved in DEHP-induced apoptosis using a mouse neuroblastoma cell line Neuro-2a, which forcibly express SCAT3, a fluorescent indicator of caspase-3 activity. The doses of DEHP at 1, 10 or 100 µM were used in the present study to mimic the level of human exposure to DEHP. Live image analysis of SCAT3-expressing Neuro-2a cells revealed that caspase-3 activity in the cells was significantly increased by DEHP at 100 µM but not 1 or 10 µM. We measured HO-1 mRNA level in Neuro-2a cells exposed to DEHP and found significant increase in HO-1 mRNA level by DEHP at 100 µM but not 1 or 10 µM. Live image analysis of SCAT3-expresisng Neuro-2a cells was further performed to determine the effects of HO-1 siRNA in DEHP-induced apoptosis via caspase-3 activation. We found that knockdown of HO-1 gene nullifies the effects of DEHP to activate caspase-3. These results suggest that HO-1 is involved in DEHP-induced apoptosis. Moreover, this study demonstrates that high-dose DEHP exposure induces caspase-3-dependent apoptosis, which is at least partially mediated by the up-regulation of HO-1 gene, in Neuro-2a cells.


Subject(s)
Apoptosis/drug effects , Apoptosis/genetics , Diethylhexyl Phthalate/toxicity , Heme Oxygenase-1/physiology , Neuroblastoma/pathology , Plasticizers/toxicity , Animals , Caspase 3/metabolism , Caspase 3/physiology , Cell Line, Tumor , Dose-Response Relationship, Drug , Gene Knockdown Techniques , Heme Oxygenase-1/genetics , Heme Oxygenase-1/metabolism , Mice , Molecular Imaging , Neuroblastoma/enzymology , RNA, Messenger/metabolism , Up-Regulation
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