Displaying publications 161 - 180 of 1115 in total

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  1. Unveiling the anti-giardial properties of Andrographis paniculata leaf extract through in vitro studies
    Haldar T, Sardar SK, Ghosal A, Das K, Saito-Nakano Y, Dutta S, et al.
    Trop Biomed, 2024 Sep 01;41(3):319-327.
    PMID: 39548787 DOI: 10.47665/tb.41.3.013
    Giardiasis, caused by the parasite Giardia lamblia, is a prevalent and serious public health concern, particularly affecting children worldwide. The primary mode of transmission for the parasite is through contaminated food and water sources and often leads to the onset of diarrhoea in infected individuals. However, the present medications for Giardiasis treatment often come with numerous side effects, while the growing problem of drug resistance adds a significant complication. Therefore, there is an urgent need for alternative treatments. In this study, we explored the in-vitro potential of Andrographis paniculata leaf extract as a possible alternative treatment for Giardiasis. Our investigation involved assessing the impact of the ethanolic extract on Giardia trophozoites through the analysis of parameters such as cell death, morphological alterations, adherence, ROS generation, and cell cycle dynamics. A. paniculata leaf extracts demonstrated significant inhibitory activity against the growth of Giardia trophozoites. After being incubated for 24 hours, the test results revealed an IC50 value of 51.26µg/ml (95% CI 37.17- 65.35) for inducing cell death in Giardia trophozoites. We observed a substantial degradation of DNA, alteration in morphology, inhibition in adherence, ROS generation and inhibition of the cell cycle in Giardia trophozoites. The findings indicate that A. paniculata extract has the potential to be used as a therapeutic treatment for giardiasis. This approach aims to offer a natural therapeutic solution for giardiasis, minimizing side effects and reducing the risk of drug resistance.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  2. Fulltext Carotenoids modulate antioxidant pathways in In vitro models of Parkinson's disease: A comprehensive scoping review
    Guo HT, Lee ZX, Magalingam KB, Radhakrishnan AK, Bhuvanendran S
    Neurochem Int, 2024 Nov;180:105857.
    PMID: 39293662 DOI: 10.1016/j.neuint.2024.105857
    Parkinson's disease (PD) is the second most common neurodegenerative disease, and it has affected the living quality of elderly people significantly. PD is characterised by the accumulation of α-Synuclein and progressive loss of dopaminergic neurons at the substantia nigra pars compacta. In the pathogenesis of Parkinson's disease, α-Synuclein, oxidative stress, and electron transport chain (ETC) are the three main factors that contribute to the production of reactive oxygen species (ROS). Currently, there is no commercial disease-modifying agent available for PD; the first-line treatment, Levodopa (l-DOPA), could only relieve the symptoms of PD, with many side effects. Carotenoids, which encompass red, orange, and yellow pigments found in nature and contribute to the colouration of plants, have been associated with various health benefits, including anti-cancer and neuroprotective effects due to their antioxidant properties. This scoping review delves into the impact and underlying mechanisms of carotenoids on cell-based models of neurodegenerative diseases.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  3. Fulltext The link between Mitochondria and Sarcopenia
    Kamarulzaman NT, Makpol S
    J Physiol Biochem, 2025 Feb;81(1):1-20.
    PMID: 39969761 DOI: 10.1007/s13105-024-01062-7
    Sarcopenia, a widespread condition, is characterized by a variety of factors influencing its development. The causes of sarcopenia differ depending on the age of the individual. It is defined as the combination of decreased muscle mass and impaired muscle function, primarily observed in association with ageing. As people age from 20 to 80 years old, there is an approximate 30% reduction in muscle mass and a 20% decline in cross-sectional area. This decline is attributed to a decrease in the size and number of muscle fibres. The regression of muscle mass and strength increases the risk of fractures, frailty, reduced quality of life, and loss of independence. Muscle cells, fibres, and tissues shrink, resulting in diminished muscle power, volume, and strength in major muscle groups. One prominent theory of cellular ageing posits a strong positive relationship between age and oxidative damage. Heightened oxidative stress leads to early-onset sarcopenia, characterized by neuromuscular innervation breakdown, muscle atrophy, and dysfunctional mitochondrial muscles. Ageing muscles generate more reactive oxygen species (ROS), and experience decreased oxygen consumption and ATP synthesis compared to younger muscles. Additionally, changes in mitochondrial protein interactions, cristae structure, and networks may contribute to ADP insensitivity, which ultimately leads to sarcopenia. Within this framework, this review provides a comprehensive summary of our current understanding of the role of mitochondria in sarcopenia and other muscle degenerative diseases, highlighting the crucial need for further research in these areas.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  4. Effects of perfluorooctanoic acid and nano titanium dioxide on the immune response and energy allocation in Mytilus coruscus
    Sun B, Hu M, Bock C, Shao Y, Chen H, Waiho K, et al.
    Chemosphere, 2025 Feb;370:143958.
    PMID: 39701318 DOI: 10.1016/j.chemosphere.2024.143958
    Perfluorooctanoic acid (PFOA) functions as a surfactant, while nano-titanium dioxide (nano-TiO2) serves as an antibacterial agent. These substances are extensively utilized in industrial production and, upon release into aquatic environments, pose significant threats to the viability and development of marine organisms. However, research into the effects of PFOA and nano-TiO2 on the immune functions and cellular energy allocation (CEA) of bivalves remains limited. To investigate the impact of PFOA and nano-TiO2 on immunity and cellular energy, we exposed Mytilus coruscus individuals to different concentrations of PFOA (2 and 200 μg/L), either alone or in combination with nano-TiO2 (0.1 mg/L, particle size: 25 nm) for 14 days. We found that the co-exposure to PFOA and nano-TiO2 had significant interactive effects on multiple immune function parameters of mussels. PFOA and nano-TiO2 notably reduced the total hemocyte count (THC), esterase activity (EST), mitochondrial number (MN), lysosomal content (LYSO), and cell viability, while concurrently elevating hemocyte mortality (HM) and reactive oxygen species (ROS) levels. Some immune-related genes, such as Tumor Necrosis Factor-alpha (TNF-α) and Myeloid Differentiation Primary Response 88 (MyD88) were downregulated, while others such as Interleukin 17 (IL-17) and Transforming Growth Factor-beta (TGF-β) were upregulated after 14-day exposure to combined pollutant exposure. Furthermore, negative effects on CEA were observed under both individual and combined pollutant stress. Therefore, PFOA and nano-TiO2 regulate cellular and humoral immunity through the regulation of immune genes as mediators, while simultaneously disrupting cellular energy metabolism. The immunotoxicity of organic and particulate pollutants, and their mixtures, thus poses a significant risk to the immune defense capabilities of mussel populations in polluted coastal environments.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  5. Dual anthelmintic and hepatoprotective potential of Populus tremula bark polysaccharide complex in vitro
    Perina EA, Buyko EE, Krivoshchekov SV, Efimova LV, Diksas EB, Kaidash OA, et al.
    Trop Biomed, 2026 Sep 01;43(3):330-341.
    PMID: 42960653 DOI: 10.47665/tb.43.3.013
    Opisthorchiasis, caused by the liver fluke Opisthorchis felineus, remains a significant public health problem in Western Siberia and other parts of Eurasia. The present study investigated the anthelmintic and hepatoprotective properties of a polysaccharide complex (PC) extracted from Populus tremula bark. Anthelmintic activity was assessed in vitro against O. felineus worms using motility scores, MTS viability assay, and propidium iodide (PI) staining. Hepatoprotective potential was evaluated in HepG2 cells using lipopolysaccharide/interferon-g (LPS/IFN-g) induced inflammation and free fatty acid (FFA) induced lipotoxicity models; reactive oxygen species (ROS), reduced glutathione (GSH), and intracellular lipid content were measured fluorimetrically. Antioxidant activity was further characterised by DPPH radical scavenging and ferrous ion chelating assays. PC significantly reduced worm motility and viability (calculated motility index decreased by approximately 45%, from 3.80 to 2.10), and induced focal tegumental PI accumulation, consistent with surface damage. In the LPS/IFN-g model, PC at 125 µg/mL decreased ROS by 14% (p=0.001) and partially restored GSH content by 25% (p=0.016). In FFA treated cells, the same concentration attenuated ROS by 15.5% (p=0.001) and reduced lipid accumulation by 22.8% (p=0.008). PC did not affect HepG2 viability. The complex demonstrated modest DPPH radicalscavenging activity (33.6% at 200 µg/mL) and a pronounced Fe2+ chelating capacity (24.70±2.63 mg EDTA equivalents/g). These first initial in vitro findings identify P. tremula bark PC as a candidate dualaction agent for treating of opisthorchiasis, combining direct anthelmintic activity with multi-targeted hepatoprotective effects that warrant confirmation in further mechanistic and in vivo studies.
    Matched MeSH terms: Reactive Oxygen Species/analysis
  6. A Smart HRV-Guided Respiratory Biofeedback System for Combined Respiratory and Psychological Recovery During COVID-19 Oxygen Weaning
    Deif MA, Hafez MA, Abdelaliem SMF, Khishe M
    Appl Psychophysiol Biofeedback, 2026 Dec;51(4):701-719.
    PMID: 41838315 DOI: 10.1007/s10484-026-09770-0
    The COVID-19 pandemic has placed substantial pressure on intensive care units (ICUs), particularly in managing patients who require oxygen therapy and must be safely weaned from it. This study evaluated an HRV-guided respiratory biofeedback program as a non-pharmacological method to reduce respiratory discomfort and psychological distress during oxygen weaning in COVID-19 patients. A non-randomized quasi-experimental study was conducted with 80 ICU patients at Albehera Hospital, Beheira, Egypt. Patients were allocated to either a biofeedback group ([Formula: see text]) or a control group ([Formula: see text]). Both groups received standard oxygen-weaning care and routine nursing support, but only the biofeedback group received structured sessions combining diaphragmatic breathing with heart rate variability based respiratory training. The Respiratory Distress Observation Scale (RDOS) and the Depression Anxiety Stress Scale (DASS-21) were administered before and after the intervention. After adjusting for baseline scores, the biofeedback group demonstrated a markedly larger reduction in RDOS scores (from 14.48 to 4.23; [Formula: see text]) and significant improvements in DASS-21 depression, anxiety, and stress subscales ([Formula: see text]), whereas the control group showed only minimal changes. These findings suggest that HRV-guided respiratory biofeedback may enhance both respiratory comfort and psychological well-being during oxygen weaning in COVID-19 patients and could serve as a valuable adjunct to standard ICU care. Further randomized controlled trials are warranted to confirm these results and guide clinical implementation.
    Matched MeSH terms: Oxygen Inhalation Therapy*
  7. α7-Nicotinic Acetylcholine Receptor Activation Modulates BV2 Microglial Plasticity via miR-21/TNF-α/NFκB in Oxygen-Glucose Deprivation/Reoxygenation
    Hasan MY, Roslan AHM, Azmi N, Ibrahim NM, Arulsamy A, Lee VLL, et al.
    J Mol Neurosci, 2024 Dec 24;75(1):2.
    PMID: 39718716 DOI: 10.1007/s12031-024-02300-9
    Elevated inflammatory reactions are a significant component in cerebral ischemia-reperfusion injury (CIRI). Activation of α7-Nicotinic Acetylcholine Receptor (α7nAChR) reduces stroke-induced inflammation in rats, but the anti-inflammatory pathway in microglia under CIRI condition remains unclear. This study employed qRT-PCR, protein assays, NanoString analysis, and bioinformatics to examine the effects of PNU282987 treatment (α7nAChR agonist) on BV2 microglial functional differentiation in oxygen-glucose deprivation/reoxygenation (OGDR) condition. OGDR significantly increased the gene expression of pro-inflammatory markers such as TNF-α, IL-6, and IL1β, while α7nAChR agonists reduced these markers. The anti-inflammatory gene marker IL-10 was upregulated by α7nAChR agonist treatment. Downstream pathway marker analysis showed that both gene and protein expression of NFκB was associated with anti-inflammatory effects. Blocking microRNA-21 with antagomir reversed the anti-inflammatory effects. NanoString analysis revealed that microRNA-21 inhibition significantly affected inflammation-related genes, including AL1RAP, TLR9, FLT1, PTGIR, NFκB, TREM2, TNF, SMAD7, FOS, CCL5, IFIT1, CFB, CXCL10, IFI44, DDIT3, IRF7, OASL1, IL1A, IFIT2, C3, CD40, STAT2, IFIT3, IL1RN, OAS1A, CSF1, CCL4, CCL2, CCL3, BCL2L1, and ITGB2. Enrichment analysis of upregulated genes identified Gene Ontology Biological Processes related to cytokine responses and TNF-associated pathways. This study highlights α7nAChR activation as a key regulator of anti-inflammatory responses in BV2 microglia under OGDR conditions, with micro-RNA21 identified as a crucial mediator of receptor-driven neuroprotection via the TNF-α/NFκB signalling pathway.
    Matched MeSH terms: Oxygen/metabolism
  8. Targeting TtVgR via siRNA Knockdown Elicits Ovarian Cell Death in the Tri-spine Horseshoe Crab
    Tan K, Ma X, Su B, Zhan C, Yang X, Waiho K, et al.
    Mar Biotechnol (NY), 2024 Jun;26(3):575-587.
    PMID: 38676851 DOI: 10.1007/s10126-024-10319-7
    The vitellogenin present in the bloodstream undergoes internalization into developing oocytes through the vitellogenin receptor (VgR), a process mediated by receptor-mediated endocytosis. VgR plays a crucial role in facilitating the accumulation of vitellogenin and the maturation of oocytes. In this study, we characterized a Tachypleus tridentatus vitellogenin receptor (TtVgR) gene from the tri-spine horseshoe crab, revealing a length of 1956 bp and encoding 652 amino acid residues with 12 exons. TtVgR has a molecular weight of 64.26 kDa and an isoelectric point of 5.95. Predictions indicate 85 phosphorylation sites and 7 glycosylation sites within TtVgR. Transcriptional analysis demonstrated specific expression of TtVgR in the ovary and yellow connective tissue. TtVgR was identified and distributed in the plasma membrane of oocytes. The siRNA-mediated TtVgR knockdown significantly reduced the transcriptional activity of TtVgR. This depletion induced excessive ROS production, resulting in DNA damage in ovarian primary cells. TUNEL and flow cytometry analyses confirmed ovarian cell apoptosis following TtVgR knockdown, indicating DNA damage in ovarian primary cells. These findings underscore the importance of TtVgR in ovarian cell development, suggesting its potential involvement in vitellogenesis and oocyte maturation. This knowledge may inform innovative breeding strategies and contribute to the sustainable management and conservation of the tri-spine horseshoe crab.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  9. Circular economy in action: palm oil kernel biochar and boiler ash enhance growth of Amaranthus viridis via ROS-induced antioxidants modulation
    Yaacob JS, Sheba M, Lee GC, Abdullah R, Rusli LS, Fariduddin Q, et al.
    Environ Sci Pollut Res Int, 2026 Jan;33(3):865-884.
    PMID: 41533037 DOI: 10.1007/s11356-025-37363-7
    Soil salinization significantly hampers global food production, posing a serious threat to food security. Biochar and boiler ash, byproducts of the oil palm industry, have shown potential as soil amendments to enhance soil quality and support plant growth under saline soils. This study evaluated the effects of biochar and boiler ash on the growth performance of Amaranthus viridis cultivated in saline soil. Plants were subjected to four treatments: saline soil (SS) without amendments (control), SS with NPK fertilizer (N), SS with NPK and biochar (BCN), and SS with NPK and boiler ash (BAN). Among the salt-stressed plants, those grown with BAN exhibited the highest plant height, leaf count, leaf width, SPAD value, and fresh and dry biomass, followed by those in the BCN treatment. Biochar application reduced the EC of the saline soil, while both biochar and boiler ash increased soil pH. Control plants recorded the lowest levels of chlorophyll a, chlorophyll b, and carotenoids. On the other hand, pigment contents were significantly improved in salt-stressed plants treated with biochar and boiler ash. BAN-treated plants showed the highest chlorophyll b levels, while BCN-treated plants exhibited the highest carotenoid and chlorophyll a levels. Furthermore, biochar and boiler ash supplementation reduced oxidative stress markers (H2O2 and MDA) while enhancing antioxidant defenses, including proline, ascorbic acid, ascorbate peroxidase, catalase, and secondary metabolites such as anthocyanins, flavonoids, and phenolic compounds. These findings suggest that biochar and boiler ash, when combined with NPK fertilizer, serve as effective soil amendments for mitigating salt stress and enhancing plant growth and physiological resilience in saline environments.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  10. Sirt1 overexpression inhibits chondrocyte ferroptosis via Ftl deacetylation to suppress the development of osteoarthritis
    Xiong X, Huang H, Wang N, Zhou K, Song X
    J Bone Miner Metab, 2025 May;43(3):203-215.
    PMID: 39786573 DOI: 10.1007/s00774-024-01574-8
    INTRODUCTION: Osteoarthritis (OA) is a chronic degenerative joint disorder characterized by an imbalance in chondrocyte metabolism. Ferroptosis has been implicated in the pathogenesis of OA. The role of Sirt1, a deacetylase, in mediating deacetylation during ferroptosis in OA chondrocytes remains underexplored. This study aimed to elucidate the mechanisms by which Sirt1 influences chondrocyte ferroptosis in the development of OA.

    MATERIALS AND METHODS: In vitro and in vivo models of OA were established using IL-1β-induced mouse chondrocytes and a destabilization of the medial meniscus (DMM) mouse model, respectively. Ferroptosis was evaluated through measurements of cell viability, lactate dehydrogenase (LDH) release, intracellular levels of Fe2+, glutathione (GSH), malondialdehyde (MDA), lipid reactive oxygen species (ROS), propidium iodide staining, and Western blot analysis. The underlying mechanisms were further investigated using quantitative real-time polymerase chain reaction, Western blotting, immunoprecipitation (IP), co-immunoprecipitation (Co-IP), and glutathione-S-transferase pulldown assays. In vivo validation was performed via Safranin O staining.

    RESULTS: IL-1β induced ferroptosis and increased histone acetylation, effects that were partially reversed by Sirt1 overexpression. Mechanistically, Sirt1 overexpression upregulated ferritin light polypeptide (Ftl) expression by deacetylating Ftl at the K181 residue. Ftl knockdown inhibited the ferroptosis-enhancing effect of Sirt1 overexpression in chondrocytes. In vivo studies showed that Sirt1 overexpression mitigated the progression of OA and reduced ferroptosis in the DMM-induced OA mouse model.

    CONCLUSION: Our findings confirm that Sirt1 overexpression promotes Ftl expression through deacetylation at the K181 site, thereby suppressing chondrocyte ferroptosis and attenuating the progression of OA. These results suggest a potential therapeutic target for OA treatment.

    Matched MeSH terms: Reactive Oxygen Species/metabolism
  11. Determination of optimum polymeric coagulant in palm oil mill effluent coagulation using multiple-objective optimisation on the basis of ratio analysis (MOORA)
    Tamrin KF, Zahrim AY
    Environ Sci Pollut Res Int, 2017 Jul;24(19):15863-15869.
    PMID: 28013466 DOI: 10.1007/s11356-016-8235-3
    The main limitation of a conventional palm oil mill effluent (POME) ponding system lies in its inability to completely decolourise effluent. Decolourisation of effluent is aesthetically and environmentally crucial. However, determination of the optimum process parameters is becoming more complex with the increase of the number of coagulants and responses. The primary objective of this study is to determine the optimum polymeric coagulant in the coagulation-flocculation process of palm oil mill effluent by considering all output responses, namely lignin-tannin, low molecular mass coloured compounds (LMMCC), chemical oxygen demand (COD), ammonia nitrogen (NH3-N), pH and conductivity. Here, multiple-objective optimisation on the basis of ratio analysis (MOORA) is employed to discretely measure multiple response characteristics of five different types of coagulants as a function of assessment value. The optimum coagulant is determined based on the highest assessment value and was identified as QF25610 (cationic polyacrylamide). On the other hand, the lowest assessment value was represented by AN1800 (anionic polyacrylamide). This study highlights the simplicity of MOORA approach in handling various input and output parameters, and it may be useful in other wastewater treatment processes as well.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  12. New monoclinic form of {O-Ethyl N-(4-nitro-phen-yl)thio-carbamato-κS}(tri-4-tolyl-phosphane-κP)gold(I): crystal structure and Hirshfeld surface analysis
    Kuan FS, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Oct 01;73(Pt 10):1465-1471.
    PMID: 29250359 DOI: 10.1107/S2056989017012865
    The title phosphanegold(I) thiol-ate compound, [Au(C9H9N2O3S)(C21H21P)], is a second monoclinic polymorph (space group P21/c) that complements a previously reported Cc polymorph [Broker & Tiekink (2008 ▸). Acta Cryst. E64, m1582]. An SP donor set defines an approximately linear geometry about the gold atom in both forms. The key distinguishing feature between the present structure and the previously reported polymorph rests with the relative disposition of the thiol-ate ligand. In the title compound, the orientation is such to place the oxygen atom in close contact with the gold atom [Au⋯O = 2.915 (2) Å], in contrast to the aryl ring in the original polymorph. In the crystal, linear supra-molecular chains along the a-axis direction mediated by C-H⋯π and nitro-O⋯π inter-actions are found. These pack with no directional inter-actions between them. The analysis of the Hirshfeld surfaces for both forms of [Au(C9H9N3O3S)(C21H21P)] indicates quite distinctive inter-action profiles relating to the differences in inter-molecular contacts found in their respective crystals.
    Matched MeSH terms: Oxygen
  13. Novel bufferless photosynthetic microbial fuel cell (PMFCs) for enhanced electrochemical performance
    Wang CT, Huang YS, Sangeetha T, Chen YM, Chong WT, Ong HC, et al.
    Bioresour Technol, 2018 May;255:83-87.
    PMID: 29414177 DOI: 10.1016/j.biortech.2018.01.086
    Photosynthetic microbial fuel cells (PMFCs) are novel bioelectrochemical transducers that employ microalgae to generate oxygen, organic metabolites and electrons. Conventional PMFCs employ non-eco-friendly membranes, catalysts and phosphate buffer solution. Eliminating the membrane, buffer and catalyst can make the MFC a practical possibility. Therefore, single chambered (SPMFC) were constructed and operated at different recirculation flow rates (0, 40 and 240 ml/min) under bufferless conditions. Furthermore, maximum power density of 4.06 mW/m2, current density of 46.34 mA/m2 and open circuit potential of 0.43 V and low internal resistance of 611.8 Ω were obtained at 40 ml/min. Based on the results it was decided that SPMFC was better for operation at 40 ml/min. Therefore, these findings provided progressive insights for future pilot and industrial scale studies of PMFCs.
    Matched MeSH terms: Oxygen
  14. Evaluation of Alkylamine Modified Pt Nanoparticles as Oxygen Reduction Reaction Electrocatalyst for Fuel Cells via Electrochemical Impedance Spectroscopy
    Joshi P, Okada T, Miyabayashi K, Miyake M
    Anal Chem, 2018 May 15;90(10):6116-6123.
    PMID: 29613775 DOI: 10.1021/acs.analchem.8b00247
    Organically (octyl amine, OA) surface modified electrocatalyst (OA-Pt/CB) was studied for its oxygen reduction reaction (ORR) activity via dc methods and its charge and mass transfer properties were studied via electrochemical impedance spectroscopy (EIS). Comparison with a commercial catalyst (TEC10V30E) with similar Pt content was also carried out. In EIS, both the catalysts showed a single time-constant with an emerging high-frequency semicircle of very small diameter which was fitted using suitable equivalent circuits. The organically modified catalyst showed lower charge-transfer resistance and hence, low polarization resistance in high potential region as compared to the commercial catalyst. The dominance of kinetic processes was observed at 0.925-1.000 V, whereas domination of diffusion based processes was observed at lower potential region for the organic catalyst. No effect due to the presence of carbon was observed in the EIS spectra. Using the hydrodynamic method, higher current penetration depth was obtained for the organically modified catalyst at 1600 rpm. Exchange current density and Tafel slopes for both the electrocatalysts were calculated from the polarization resistance obtained from EIS which was in correlation with the results obtained from dc methods.
    Matched MeSH terms: Oxygen
  15. Tunable Spectrum Selectivity for Multiphoton Absorption with Enhanced Visible Light Trapping in ZnO Nanorods
    Tan KH, Lim FS, Toh AZY, Zheng XX, Dee CF, Majlis BY, et al.
    Small, 2018 May;14(20):e1704053.
    PMID: 29665226 DOI: 10.1002/smll.201704053
    Observation of visible light trapping in zinc oxide (ZnO) nanorods (NRs) correlated to the optical and photoelectrochemical properties is reported. In this study, ZnO NR diameter and c-axis length respond primarily at two different regions, UV and visible light, respectively. ZnO NR diameter exhibits UV absorption where large ZnO NR diameter area increases light absorption ability leading to high efficient electron-hole pair separation. On the other hand, ZnO NR c-axis length has a dominant effect in visible light resulting from a multiphoton absorption mechanism due to light reflection and trapping behavior in the free space between adjacent ZnO NRs. Furthermore, oxygen vacancies and defects in ZnO NRs are associated with the broad visible emission band of different energy levels also highlighting the possibility of the multiphoton absorption mechanism. It is demonstrated that the minimum average of ZnO NR c-axis length must satisfy the linear regression model of Z p,min = 6.31d to initiate the multiphoton absorption mechanism under visible light. This work indicates the broadening of absorption spectrum from UV to visible light region by incorporating a controllable diameter and c-axis length on vertically aligned ZnO NRs, which is important in optimizing the design and functionality of electronic devices based on light absorption mechanism.
    Matched MeSH terms: Oxygen
  16. Fulltext Effect of operating parameters on decolourisation of Palm Oil Mill Effluent (POME) using electrocoagulation process
    Nur Syuhaidah Mohd Aris, Shariff Ibrahim, Borhannuddin Arifin, Yahaya Hawari
    Pertanika Journal of Science & Technology, 2017;25(107):297-206.
    MyJurnal
    Electrocoagulation has proven to be an effective method in the treatment of wastewater. This study evaluated the decolourisation of Palm Oil Mill Effluent (POME) using electrocoagulation (EC) batch reactor by utilising aluminium as sacrificial electrode. POME sample source from a final discharged pond at a palm oil mill was characterised for its colour, chemical oxygen demand (COD), pH, conductivity and turbidity; were found to be 2707 PtCo, 3909 mg/L, 7.63, 12.82 mS/cm and 755 NTU respectively. The respective effects of operating parameters such as pH (3 to 11), applied voltage (5 V to 20 V), plate gap (7.5 to 11.5 cm) and operating time (1 to 8 hours) were investigated. The decolourisation of POME was observed to increase with increasing voltage and operating time. Highest removal efficiency was observed at pH 5, 20 V applied voltage, 9.5 cm plate gap and at 8-hour operating time with colour removal efficiency of 89, 79, 78 and 64% respectively. From the findings, it can be concluded that electrocoagulation process using aluminium electrodes is a reliable technique for the removal of colour from POME.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  17. Fulltext Trend analysis of water quality at Sungai Sarawak
    Yuhani Jamian, Zainap Lamat, Nurazura Rali
    Pertanika Journal of Science & Technology, 2017;25(105):55-62.
    MyJurnal
    Sungai Sarawak is the most important river in Sarawak. This study was aimed at assessing water quality in the selected stations from Satok bridge to the downstream, Muara Tebas, located along Sungai Sarawak. Water quality trend analysis was conducted to determine the correlation between the water quality parameters. Trend analysis was carried out using Mann-Kendall Test because data collected was non-parametric. Next, Spearman rank was used in order to determine the correlation between parameters. The results obtained and the observation made in this study reveals that the trend exists only for Chemical Oxygen Value (COD). But there are trends for Biochemical Oxygen Demand, (BOD), Dissolved Oxygen (DO), Total Suspended Solid (TSS), Ammoniacal Nitrogen (NH4N) and Turbidity to decrease or increase with no trends between 2007 and 2011. The correlation between parameters is not very strong because there are many determinants of water quality parameters. The result from this study would provide useful information for water quality management in order to maintain and improve the water quality of Sungai Sarawak.
    Matched MeSH terms: Oxygen
  18. Determination of biochemical oxygen demand and dissolved oxygen for semi-arid river environment: application of soft computing models
    Tao H, Bobaker AM, Ramal MM, Yaseen ZM, Hossain MS, Shahid S
    Environ Sci Pollut Res Int, 2019 Jan;26(1):923-937.
    PMID: 30421367 DOI: 10.1007/s11356-018-3663-x
    Surface and ground water resources are highly sensitive aquatic systems to contaminants due to their accessibility to multiple-point and non-point sources of pollutions. Determination of water quality variables using mathematical models instead of laboratory experiments can have venerable significance in term of the environmental prospective. In this research, application of a new developed hybrid response surface method (HRSM) which is a modified model of the existing response surface model (RSM) is proposed for the first time to predict biochemical oxygen demand (BOD) and dissolved oxygen (DO) in Euphrates River, Iraq. The model was constructed using various physical and chemical variables including water temperature (T), turbidity, power of hydrogen (pH), electrical conductivity (EC), alkalinity, calcium (Ca), chemical oxygen demand (COD), sulfate (SO4), total dissolved solids (TDS), and total suspended solids (TSS) as input attributes. The monthly water quality sampling data for the period 2004-2013 was considered for structuring the input-output pattern required for the development of the models. An advance analysis was conducted to comprehend the correlation between the predictors and predictand. The prediction performances of HRSM were compared with that of support vector regression (SVR) model which is one of the most predominate applied machine learning approaches of the state-of-the-art for water quality prediction. The results indicated a very optimistic modeling accuracy of the proposed HRSM model to predict BOD and DO. Furthermore, the results showed a robust alternative mathematical model for determining water quality particularly in a data scarce region like Iraq.
    Matched MeSH terms: Oxygen/analysis; Biological Oxygen Demand Analysis*
  19. Fulltext Direct high-resolution mapping of electrocatalytic activity of semi-two-dimensional catalysts with single-edge sensitivity
    Sun T, Wang D, Mirkin MV, Cheng H, Zheng JC, Richards RM, et al.
    Proc Natl Acad Sci U S A, 2019 06 11;116(24):11618-11623.
    PMID: 31127040 DOI: 10.1073/pnas.1821091116
    The catalytic activity of low-dimensional electrocatalysts is highly dependent on their local atomic structures, particularly those less-coordinated sites found at edges and corners; therefore, a direct probe of the electrocatalytic current at specified local sites with true nanoscopic resolution has become critically important. Despite the growing availability of operando imaging tools, to date it has not been possible to measure the electrocatalytic activities from individual material edges and directly correlate those with the local structural defects. Herein, we show the possibility of using feedback and generation/collection modes of operation of the scanning electrochemical microscope (SECM) to independently image the topography and local electrocatalytic activity with 15-nm spatial resolution. We employed this operando microscopy technique to map out the oxygen evolution activity of a semi-2D nickel oxide nanosheet. The improved resolution and sensitivity enables us to distinguish the higher activities of the materials' edges from that of the fully coordinated surfaces in operando The combination of spatially resolved electrochemical information with state-of-the-art electron tomography, that unravels the 3D complexity of the edges, and ab initio calculations allows us to reveal the intricate coordination dependent activity along individual edges of the semi-2D material that is not achievable by other methods. The comparison of the simulated line scans to the experimental data suggests that the catalytic current density at the nanosheet edge is ∼200 times higher than that at the NiO basal plane.
    Matched MeSH terms: Oxygen
  20. Effect of pro-degradant additive on photo-oxidative aging of polypropylene film
    Noor Zalikha Mohamed Islam, Nadras Othman, Zulkifli Ahmad, Hanafi Ismail
    Sains Malaysiana, 2011;40:1123-1127.
    This paper describes the effect of pro-degradant additives (PDA) on photo-oxidative aging of polypropylene (PP) films after being time accelerated in UV-weathering chamber. Thin films (0.12 mm) containing these additives were prepared by sheeting process. The effect of UV on PP films in the presence of these additives was investigated. Changes in the PP films appearance, tensile properties and carbonyl index (CI) were used to investigate the degradation behavior. The films became completely pulverised after 100 h of photo-oxidative treatment and could not be tested further. Films containing PDA showed rapid loss in tensile properties within 100 h of photo-oxidative aging. In addition, the CI results of photo-oxidative films increased with increasing PDA amount within the time interval of aging and the activity was due to the mechanism reaction of PP with PDA particles. During the aging process the material becomes denser due to tighter packing and incorporation of oxygen into the amorphous regions of the polymer. The results indicated that the presence of PDA contributed to the photo degradation and the activity was very much influenced by the amount PDA.
    Matched MeSH terms: Oxygen
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