Displaying publications 121 - 140 of 1088 in total

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  1. Fulltext Synthesis of epoxidized palm oil-based trimethylolpropane ester by in situ epoxidation method
    Ferra Naidir, Robiah Yunus, Tinia Idaty Mohd. Ghazi, Irmawati Ramli
    Pertanika Journal of Science & Technology, 2012;20(2):331-337.
    MyJurnal
    Palm oil-based Trimethylolpropane ester (TMP ester), with an iodine value of 66.4 g/100g, was epoxidizedto produce epoxidized TMP esters. In situ epoxidation method was used with peracetic acid to eliminatefatty acid double bonds in palm oil-based TMP ester and change it into oxirane ring. This was done toimprove the oxidative stability of trimethylolpropane ester which is a key concern limiting the usefulservice life in lubricants. The epoxidation was performed by reacting acetic acid as active oxygen carrierwith concentrated hydrogen peroxide as oxygen donor and a small amount of homogeneous catalyst(sulphuric acid). The effects of various parameters on the rate of epoxidation (such as the ratio of moleacetic acid to ethylenic unsaturation, hydrogen peroxide to ethylenic unsaturation and acetic acid moleratio, and amount of catalyst) were studied. The rate of oxidation was investigated by the percentageof oxirane oxygen analysis and iodine value.
    Matched MeSH terms: Oxygen; Reactive Oxygen Species
  2. The maximum aerobic power of the Temiars
    Chan OL, Duncan MT, Sundsten JW, Thinakaran T, Noh MN, Klissouras V
    Med Sci Sports, 1976;8(4):235-8.
    PMID: 1011961
    A settlement of Temiars, an aboriginal tribe residing in the north-eastern jungles of the Malay Peninsula, was selected for a study of their cardiorespiratory fitness. A step-test was used to elicit the Vo2max, V E max and HR max in a group of 19 boys aged 12 to 18 years and 6 men aged 19 - 40 years. The mean VO2max of the boys was found to be 45.9 +/- 6.9 ml-kg-1-min-1 compared with 45.6 +/- 5.4 ml-kg-1-min-1 for the men. The mean V E max, HR max and blood lactate levels were found to be 65.5 +/- 11.31/min and 69.2 +/- 23.71/min; 194 +/- 8 beats/min and 186 +/- 10 beats/min; and 79.8 +/- 13.4 mg% and 97.7 +/- 33.4 mg% respectively. These results are comparable to those obtained in urban populations as well as those found in other primitive communities. Telemetric monitoring of the routine daily physical activity of the men revealed that these jungle dwellers rarely tax their oxygen transport systems in their daily living and their cardiorespiratory functions were similar to communities who do not specifically train for physical fitness.
    Matched MeSH terms: Oxygen*
  3. Reactive Black 5 as electron donor and/or electron acceptor in dual chamber of solar photocatalytic fuel cell
    Khalik WF, Ho LN, Ong SA, Voon CH, Wong YS, Yusuf SY, et al.
    Chemosphere, 2018 Jul;202:467-475.
    PMID: 29579681 DOI: 10.1016/j.chemosphere.2018.03.113
    The role of azo dye Reactive Black 5 (RB5) as an electron donor and/or electron acceptor could be distinguished in dual chamber of photocatalytic fuel cell (PFC). The introduction of RB5 in anode chamber increased the voltage generation in the system since degradation of RB5 might produce electrons which also would transfer through external circuit to the cathode chamber. The removal efficiency of RB5 with open and closed circuit was 8.5% and 13.6%, respectively and removal efficiency for open circuit was low due to the fact that recombination of electron-hole pairs might happen in anode chamber since without connection to the cathode, electron cannot be transferred. The degradation of RB5 in cathode chamber with absence of oxygen showed that electrons from anode chamber was accepted by dye molecules to break its azo bond. The presence of oxygen in cathode chamber would improve the oxygen reduction rate which occurred at Platinum-loaded carbon (Pt/C) cathode electrode. The Voc, Jsc and Pmax for different condition of ultrapure water at cathode chamber also affected their fill factor. The transportation of protons to cathode chamber through Nafion membrane could decrease the pH of ultrapure water in cathode chamber and undergo hydrogen evolution reaction in the absence of oxygen which then increased degradation rate of RB5 as well as its electricity generation.
    Matched MeSH terms: Oxygen/chemistry
  4. Connecting salt stress signalling pathways with salinity-induced changes in mitochondrial metabolic processes in C3 plants
    Che-Othman MH, Millar AH, Taylor NL
    Plant Cell Environ, 2017 Dec;40(12):2875-2905.
    PMID: 28741669 DOI: 10.1111/pce.13034
    Salinity exerts a severe detrimental effect on crop yields globally. Growth of plants in saline soils results in physiological stress, which disrupts the essential biochemical processes of respiration, photosynthesis, and transpiration. Understanding the molecular responses of plants exposed to salinity stress can inform future strategies to reduce agricultural losses due to salinity; however, it is imperative that signalling and functional response processes are connected to tailor these strategies. Previous research has revealed the important role that plant mitochondria play in the salinity response of plants. Review of this literature shows that 2 biochemical processes required for respiratory function are affected under salinity stress: the tricarboxylic acid cycle and the transport of metabolites across the inner mitochondrial membrane. However, the mechanisms by which components of these processes are affected or react to salinity stress are still far from understood. Here, we examine recent findings on the signal transduction pathways that lead to adaptive responses of plants to salinity and discuss how they can be involved in and be affected by modulation of the machinery of energy metabolism with attention to the role of the tricarboxylic acid cycle enzymes and mitochondrial membrane transporters in this process.
    Matched MeSH terms: Oxygen/metabolism*
  5. Performance of modified anaerobic inclining-baffled reactor treating recycled paper mill effluent: effects of influent chemical oxygen demand concentration and hydraulic retention time
    Zwain HM, Aziz HA, Dahlan I
    Environ Technol, 2018 Jun;39(12):1557-1565.
    PMID: 28514902 DOI: 10.1080/09593330.2017.1332692
    The performance of modified anaerobic inclining-baffled reactor (MAI-BR) treating recycled paper mill effluent (RPME) was investigated by varying the influent chemical oxygen demand (CODin) concentration from 1000 to 4000 mg/L, and the hydraulic retention time (HRT) from 3 to 1 day, corresponding to an organic loading rate increase from 0.33 to 4 g COD/L day. Throughout 126 days of operation, a maximum removal efficiency of up to 96% of chemical oxygen demand (COD) and 99% of biological oxygen demand, methane (CH4) yield of 0.259 L CH4/g COD, and a stable effluent pH of 6.5 were achieved. Furthermore, the compartmental performance showed that most of the organic substrates were removed in the initial two compartments, resulting in low pH and alkalinity levels and a high concentration of volatile fatty acids. Overall, the results showed that the MAI-BR successfully treated RPME, and the performance was affected by the variation of HRT more than the CODin.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  6. Estimating the refractive index of oxygenated and deoxygenated hemoglobin using genetic algorithm - support vector regression model
    Alade IO, Bagudu A, Oyehan TA, Rahman MAA, Saleh TA, Olatunji SO
    Comput Methods Programs Biomed, 2018 Sep;163:135-142.
    PMID: 30119848 DOI: 10.1016/j.cmpb.2018.05.029
    BACKGROUND AND OBJECTIVES: The refractive index of hemoglobin plays important role in hematology due to its strong correlation with the pathophysiology of different diseases. Measurement of the real part of the refractive index remains a challenge due to strong absorption of the hemoglobin especially at relevant high physiological concentrations. So far, only a few studies on direct measurement of refractive index have been reported and there are no firm agreements on the reported values of refractive index of hemoglobin due to measurement artifacts. In addition, it is time consuming, laborious and expensive to perform several experiments to obtain the refractive index of hemoglobin. In this work, we proposed a very rapid and accurate computational intelligent approach using Genetic Algorithm/Support Vector Regression models to estimate the real part of the refractive index for oxygenated and deoxygenated hemoglobin samples.

    METHODS: These models utilized experimental data of wavelengths and hemoglobin concentrations in building highly accurate Genetic Algorithm/Support Vector Regression model (GA-SVR).

    RESULTS: The developed methodology showed high accuracy as indicated by the low root mean square error values of 4.65 × 10-4 and 4.62 × 10-4 for oxygenated and deoxygenated hemoglobin, respectively. In addition, the models exhibited 99.85 and 99.84% correlation coefficients (r) for the oxygenated and deoxygenated hemoglobin, thus, validating the strong agreement between the predicted and the experimental results CONCLUSIONS: Due to the accuracy and relative simplicity of the proposed models, we envisage that these models would serve as important references for future studies on optical properties of blood.

    Matched MeSH terms: Oxygen/chemistry*
  7. Application of interface material and effects of oxygen gradient on the performance of single-chamber sediment microbial fuel cells (SSMFCs)
    Wang CT, Sangeetha T, Yan WM, Chong WT, Saw LH, Zhao F, et al.
    J Environ Sci (China), 2019 Jan;75:163-168.
    PMID: 30473281 DOI: 10.1016/j.jes.2018.03.013
    Single-chamber sediment microbial fuel cells (SSMFCs) have received considerable attention nowadays because of their unique dual-functionality of power generation and enhancement of wastewater treatment performance. Thus, scaling up or upgrading SSMFCs for enhanced and efficient performance is a highly crucial task. Therefore, in order to achieve this goal, an innovative physical technique of using interface layers with four different pore sizes embedded in the middle of SSMFCs was utilized in this study. Experimental results showed that the performance of SSMFCs employing an interface layer was improved regardless of the pore size of the interface material, compared to those without such layers. The use of an interface layer resulted in a positive and significant effect on the performance of SSMFCs because of the effective prevention of oxygen diffusion from the cathode to the anode. Nevertheless, when a smaller pore size interface was utilized, better power performance and COD degradation were observed. A maximum power density of 0.032mW/m2 and COD degradation of 47.3% were obtained in the case of an interface pore size of 0.28μm. The findings in this study are of significance to promote the future practical application of SSMFCs in wastewater treatment plants.
    Matched MeSH terms: Oxygen*
  8. Seasonal and spatial variability of selected surface water quality parameters in Setiu Wetland, Terengganu, Malaysia
    Suratman S, Hussein A, Mohd Tahir N, Latif M, Mostapa R, Weston K
    Sains Malaysiana, 2016;45:551-558.
    This paper presents the results for surface water quality parameters measured in the Setiu Wetland, on the east coast of Malaysia, which feeds into the southern part of the South China Sea. There are no previous studies dealing with the seasonal and spatial variation of water quality in this area, despite numerous anthropogenic inputs into this ecologically and economically important wetland. The parameters measured were salinity, temperature, dissolved oxygen (DO), pH, biological oxygen demand (BOD) and total suspended solids (TSS). These parameters were sampled monthly from October 2009 to September 2010, during both the wet and dry seasons, at ten sampling stations distributed throughout the area. The physical water quality parameters were measured in situ whilst TSS and BOD were determined using the standard methods. A deterioration of water quality in the Setiu Wetland was observed in areas near agriculture and aquaculture activities. This was expected to be as a result of the use of fertilisers, waste from fish farm food and the waste products of aquaculture. The parameters measured showed lower mean values of surface salinity, temperature, DO, pH and TSS during the wet season relative to the dry season. In contrast, the concentration of BOD was high during the wet season and lowest in the dry season. Results obtained from this study clearly showed the surface physical water quality for the Setiu Wetland was highly influenced by anthropogenic activities and seasonal variation. Therefore, both factors must be considered to move towards proper management of this wetland.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  9. Reassessment of physico-chemical water quality in Setiu Wetland, Malaysia
    Suratman S, Hussein A, Latif M, Weston K
    Sains Malaysiana, 2014;43:1127-1131.
    Setiu Wetland is located in the southern part of South China Sea, Malaysia. This wetland has diverse ecosystems that represent a vast array of biological diversity and abundance in utilizable natural resources. However, there are large scales of aquaculture activities within and nearby the wetland which could threaten the ecosystems of this area. Thus, the main goal of the study was to assess the impact of these activities through the measurement of physico-chemical water quality parameters and then compare this to a previous study carried out in the same study area. The parameters (salinity, temperature, pH, dissolved oxygen, biological oxygen demand and total suspended solids) were monitored monthly at the surface water from July to October 2008. The results showed that the impact of aquaculture activities on the water quality in the area with dissolved oxygen and total suspended solids concentrations were considerably lower than those observed previously. With respect to the Malaysian Marine Water Quality Criteria and Standard, most of the level of parameters measured remained Class 1, suggesting the physico-chemical environment were in line with sustainable conservation of the marine protected areas and marine parks of this wetland area.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  10. Spatial and temporal risk quotient based river assessment for water resources management
    Wan Mohtar WHM, Abdul Maulud KN, Muhammad NS, Sharil S, Yaseen ZM
    Environ Pollut, 2019 May;248:133-144.
    PMID: 30784832 DOI: 10.1016/j.envpol.2019.02.011
    Malaysia depends heavily on rivers as a source for water supply, irrigation, and sustaining the livelihood of local communities. The evolution of land use in urban areas due to rapid development and the continuous problem of illegal discharge have had a serious adverse impact on the health of the country's waterways. Klang River requires extensive rehabilitation and remediation before its water could be utilised for a variety of purposes. A reliable and rigorous remediation work plan is needed to identify the sources and locations of streams that are constantly polluted. This study attempts to investigate the feasibility of utilising a temporal and spatial risk quotient (RQ) based analysis to make an accurate assessment of the current condition of the tributaries in the Klang River catchment area. The study relies on existing data sets on Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), and Ammonia (NH3) to evaluate the water quality at thirty strategic locations. Analysis of ammonia pollution is not only based on the limit established for river health but was expanded to include the feasibility of using the water for water intake, recreational activities, and sustaining fish population. The temporal health of Klang River was evaluated using the Risk Matrix Approach (RMA) based on the frequency of RQ > 1 and associated colour-coded hazard impacts. By using the developed RMA, the hazard level for each parameter at each location was assessed and individually mapped using Geographic Information System (GIS). The developed risk hazard mapping has high potential as one of the essential tools in making decisions for a cost-effective river restoration and rehabilitation.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  11. Cardiopulmonary exercise testing: utility in research and patient care
    Elina RA, Husain R, Lang CC
    JUMMEC, 2005;8:9-22.
    Cardiopulmonary exercise testing is a non-invasive physiological test which incorporates the conventional method of exercise stress test with a more advanced breath-to-breath ventilatory analysis. The physiological parameters obtained from the test help to illustrate the cardiovascular, respiratory and metabolic responses to physical exertion. Individual's functional capacity and aerobic fitness is reflected by the value of maximal oxygen consumption (VO2 max) obtained from the cardiopulmonary exercise test. This non-invasive and sophisticated test is regarded as a valuable assessment tool in research and clinical practice. Cardiopulmonary exercise test has been extensively utilized to define the mechanisms of exercise intolerance in various clinical disorders, to evaluate responses to therapy and indicate disease prognosis. Emerging data obtained from the use of the cardiopulmonary exercise testing in the research field, has led to its extensive clinical usage. It is now utilized as an integral part of the patients' clinical evaluation in the field of respiratory and cardiovascular medicine, sports medicine, surgery as well as occupational and rehabilitative medicine. It has a clinical role in assessing patient's functional capacity, monitoring disease progression and response to therapy, predicting prognosis, and perioperative morbidity and mortality, as well as constructing and monitoring training and rehabilitative programs. This article aims to give an overview of the physiological profiles obtained from cardiopulmonary exercise testing, its methodological aspects, as well as its utility in research and clinical practice. KEYWORDS: Cardiopulmonary, exercise, physiology, respiratory medicine, oxygen consumption
    Matched MeSH terms: Oxygen; Oxygen Consumption
  12. Epoxidized natural rubber/polyvinyl chloride/microcrystalline cellulose (ENR/PVC/MCC) composite membrane for palm oil mill effluent (POME) treatment
    Aina Aqila Arman Alim, Rizafizah Othaman
    Sains Malaysiana, 2018;47:1517-1525.
    Epoxidized natural rubber/polyvinyl chloride/microcrystalline cellulose (ENR/PVC/MCC) composite membranes were
    prepared and used to treat palm oil mill effluent (POME). The loadings of MCC were varied at 0, 5, 10 and 15 w/w%. The
    increment of MCC loads has intensified the hydroxyl peak of the membranes in FTIR spectrum, indicating the increase
    in membrane hydrophilicity. MCC acted as a pore forming agent since the ENR/PVC/10% MCC gave the highest water
    flux and well-distributed pores. After first treatment of POME, the levels of chemical oxygen demand (COD), biochemical
    oxygen demand (BOD) and total suspended solid (TSS) were reduced to 99.9%, 70.3%, and 16.9%, respectively. These
    data showed that ENR/PVC/MCC membrane has the potential to treat POME.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  13. Fulltext An evaluation of subcritical hydrothermal treatment of end-of-pipe palm oil mill effluent
    Lee ZS, Chin SY, Cheng CK
    Heliyon, 2019 Jun;5(6):e01792.
    PMID: 31245637 DOI: 10.1016/j.heliyon.2019.e01792
    This study evaluates the effects of subcritical hydrothermal treatment on palm oil mill effluent (POME) and its concomitant formations of solid hydrochar, liquid product and gaseous product. The reactions were carried out at temperatures ranged 493 K-533 K for 2 h. The highest reduction of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were 58.8% and 62.5%, respectively, at 533 K. In addition, the removal of total suspended solids (TSS) achieved up to 99%, with the pH of POME reaching 6 from the initial pH 4. The gas chromatography coupled with mass spectroscopy (GC-MS) analysis showed that the fresh POME contained n-Hexadecanoic acid as the dominant component, which gradually reduced in the liquid product in the reaction with increased temperature, in addition to the attenuation of carboxyl compounds and elevation of phenolic components. The gaseous products contained CO2, CO, H2, and C3 - C6 hydrocarbons. Traces of CH4 were only found at 533 K. CO2 is the dominant species, where the highest of 3.99 vol% per 500 mL working volume of POME recorded at 533 K. The solid hydrochars showed negligible morphological changes across the reaction temperature. The O/C atomic ratio of the hydrochar range from 0.157 to 0.379, while the H/C atomic ratio was in the range from 0.930 to 1.506. With the increase of treatment temperature, the higher heating value (HHV) of the hydrochar improved from 24.624 to 27.513 MJ kg-1. The characteristics of hydrochar make it a fuel source with immense potential. POME decomposed into water-soluble compounds, followed by deoxygenation (dehydration and decarboxylation) in producing hydrochar with lower oxygen content and higher aromatic compounds in the liquid product. Little gaseous hydrocarbons were produced due to subcritical hydrothermal gasification at low temperature.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  14. Fulltext Coupled Oxides/LLDPE Composites for Textile Effluent Treatment: Effect of Neem and PVA Stabilization
    Basiron N, Sreekantan S, Kang LJ, Akil HM, Mydin RBSMN
    Polymers (Basel), 2020 Feb 09;12(2).
    PMID: 32050485 DOI: 10.3390/polym12020394
    The polyvinyl alcohol (PVA) and neem extract were grafted onto coupled oxides (3ZT-CO) via reflux process to stabilize the particles to form 3ZT-CO/PVA and 3ZT-CO/Neem. These were then incorporated into LLDPE by melt blending process to give LLDPE/3ZT-CO/PVA and LLDPE/3ZT-CO/Neem composites. The Neem and PVA stabilized particles showed high zeta potential and dispersed homogeneously in water. The stabilization process altered the shape of the particles due to plane growth along the (002) polar direction. The stabilizers acted as capping agents and initiated the one-dimensional growth. The alkyl chain groups from PVA increased the polarity of the LLDPE/3ZT-CO/PVA and played a dominant role in the water adsorption process to activate the photocatalytic activity. This was further enhanced by the homogeneous distribution of the particles and low degree of crystallinity (20.87%) of the LLDPE composites. LLDPE/3ZT-CO/PVA exhibited the highest photodegradation (93.95%), which was better than the non-stabilized particles. Therefore, the photocatalytic activity of a polymer composite can be enhanced by grafting PVA and neem onto couple oxides. The LLDPE/3ZT-CO/PVA composite was further used to treat textile effluent. The results showed the composite was able to remove dye color by 93.95% and to reduce biochemical oxygen demand (BOD) and chemical oxygen demand (COD) by 99.99%.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  15. Fulltext Synchronous activity lowers the energetic cost of nest escape for sea turtle hatchlings
    Rusli MU, Booth DT, Joseph J
    J Exp Biol, 2016 05 15;219(Pt 10):1505-13.
    PMID: 27207954 DOI: 10.1242/jeb.134742
    A potential advantage of group movement in animals is increased locomotion efficiency. This implies a reduced energetic cost for individuals that occur in larger groups such as herds, flocks and schools. When chelonian hatchlings hatch in the underground nest with finite energy for their post-hatching dispersal phase, they face the challenge of minimizing energetic expenditure while escaping the nest. The term 'social facilitation' has been used to describe the combined digging effort of sea turtle hatchlings during nest escape. Given that in a normal clutch, a substantial part of the energy reserve within the residual yolk is used by hatchlings in the digging out process, a decreased cohort size may reduce the energy reserve available to cross the beach and sustain the initial swimming frenzy. This hypothesis was experimentally tested by varying cohort size in hatchling green turtles (Chelonia mydas) and measuring energy expenditure during the nest escape process using open-flow respirometry. The energetic cost of escaping through 40 cm of sand was calculated to vary between 4.4 and 28.3 kJ per individual, the cost decreasing as the number of individuals in the cohort increased. This represents 11-68% of the energy contained in a hatchling's residual yolk at hatching. The reduced energetic cost associated with large cohorts resulted from both a lower metabolic rate per individual and a shortened nest escape time. We conclude that synchronous digging activity of many hatchlings during nest escape evolved not only to facilitate rapid nest emergence but also to reduce the energetic cost to individuals.
    Matched MeSH terms: Oxygen Consumption/physiology
  16. Cytoprotective Effects of the Tiger's Milk Mushroom Lignosus rhinocerotis (Agaricomycetes) Sclerotia against Oxidative Stress in PC12 Cells
    Tan YH, Lim CSY, Wong KH, Sabaratnam V
    Int J Med Mushrooms, 2022;24(12):1-17.
    PMID: 36374978 DOI: 10.1615/IntJMedMushrooms.2022045352
    Lignosus rhinocerotis (Cooke) Ryvarden has been reported to possess numerous pharmacological effects. However, little is known about its potential role in mitigating the detrimental effects of oxidative stress. The present study investigated the cytoprotective effects of L. rhinocerotis extracts against hydrogen peroxide (H2O2)-induced oxidative stress of rat pheochromocytoma (PC12) cells. In the pre-treatment model, PC12 cells were pre-treated with aqueous (LRAQ) or ethanolic (LRET) extracts of L. rhinocerotis for 24 h, followed by 30 μM of H2O2 for 24 h. In the co-treatment model, the cells were incubated with LRAQ or LRET and H2O2 for 2 or 24 h to induce oxidative stress. Cell viability, intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and apoptotic cells with activated caspase-3/7 were quantified. Additionally, LRET was separated into fractions by chromatographic methods prior to analysis by gas chromatography-mass spectrometry (GCMS). 320 μg/ml aqueous extract showed a significant cytoprotective effect of 70.0 ± 22.4% and 133.92 ± 8.8% in the pre-treatment and co-treatment models, respectively, compared to untreated H2O2-challenged cells. LRAQ also showed a reduction (p < 0.05) in the percentage of depolarized cells of 37.6 ± 0.6% at 640 ug/ml and 53.4 ± 4.5% at 320 ug/ml in the pre-treatment and co-treatment models, respectively, compared to untreated H2O2-challenged cells. LRAQ or LRET showed a reduction (p < 0.01) in caspase 3/7 activity compared to untreated H2O2-challenged cells in the co-treatment model. However, LRAQ or LRET did not reduce excessive ROS formation (p > 0.05). The cytoprotective effects could be attributed to the presence of fatty acids, phenols, phytosterols, and dicarboxylic acids. In conclusion, L. rhinocerotis extracts demonstrated cytoprotective effects against H2O2-induced oxidative stress in an in vitro model, contributing to the maintenance of cellular integrity through the regulation of mitochondrial function and apoptosis.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  17. Stability of folic acid under several parameters
    Gazzali AM, Lobry M, Colombeau L, Acherar S, Azaïs H, Mordon S, et al.
    Eur J Pharm Sci, 2016 Oct 10;93:419-30.
    PMID: 27575880 DOI: 10.1016/j.ejps.2016.08.045
    Folic acid is a small molecule, also known as vitamin B9. It is an essential compound involved in important biochemical processes. It is widely used as a vector for targeted treatment and diagnosis especially in cancer therapeutics. Nevertheless, not many authors address the problem of folic acid degradation. Several researchers reported their observations concerning its denaturation, but they generally only took into account one parameter (pH, temperature, light or O2etc.). In this review, we will focus on five main parameters (assessed individually or in conjunction with one or several others) that have to be taken into account to avoid the degradation of folic acid: light, temperature, concentration, oxygen and pH, which are the most cited in the literature. Scrupulous bibliographic research enabled us to determine two additional degradation factors that are the influence of singlet oxygen and electron beam on folic acid stability, which are not considered as among the prime factors. Although these two factors are not commonly present as compared to the others, singlet oxygen and electron beams intervene in new therapeutic technologies and must be taken in consideration for further applications such photodynamic or X-rays therapies.
    Matched MeSH terms: Oxygen/chemistry
  18. Potential of porous Co3O4 nanorods as cathode catalyst for oxygen reduction reaction in microbial fuel cells
    Kumar R, Singh L, Zularisam AW, Hai FI
    Bioresour Technol, 2016 Nov;220:537-542.
    PMID: 27614156 DOI: 10.1016/j.biortech.2016.09.003
    This study aims to investigate the potential of porous Co3O4 nanorods as the cathode catalyst for oxygen reduction reaction (ORR) in aqueous air cathode microbial fuel cells (MFCs). The porous Co3O4 nanorods were synthesized by a facile and cost-effective hydrothermal method. Three different concentrations (0.5mg/cm(2), 1mg/cm(2), and 2mg/cm(2)) of Co3O4 nanorods coated on graphite electrodes were used to test its performance in MFCs. The results showed that the addition of porous Co3O4 nanorods enhanced the electrocatalytic activity and ORR kinetics significantly and the overall resistance of the system was greatly reduced. Moreover, the MFC with a higher concentration of the catalyst achieved a maximum power density of 503±16mW/m(2), which was approximately five times higher than the bare graphite electrode. The improved catalytic activity of the cathodes could be due to the porous properties of Co3O4 nanorods that provided the higher number of active sites for oxygen.
    Matched MeSH terms: Oxygen/chemistry*
  19. Role of dissolved oxygen on the degradation mechanism of Reactive Green 19 and electricity generation in photocatalytic fuel cell
    Lee SL, Ho LN, Ong SA, Wong YS, Voon CH, Khalik WF, et al.
    Chemosphere, 2018 Mar;194:675-681.
    PMID: 29247929 DOI: 10.1016/j.chemosphere.2017.11.166
    In this study, a membraneless photocatalytic fuel cell with zinc oxide loaded carbon photoanode and platinum loaded carbon cathode was constructed to investigate the impact of dissolved oxygen on the mechanism of dye degradation and electricity generation of photocatalytic fuel cell. The photocatalytic fuel cell with high and low aeration rate, no aeration and nitrogen purged were investigated, respectively. The degradation rate of diazo dye Reactive Green 19 and the electricity generation was enhanced in photocatalytic fuel cell with higher dissolved oxygen concentration. However, the photocatalytic fuel cell was still able to perform 37% of decolorization in a slow rate (k = 0.033 h-1) under extremely low dissolved oxygen concentration (approximately 0.2 mg L-1) when nitrogen gas was introduced into the fuel cell throughout the 8 h. However, the change of the UV-Vis spectrum indicates that the intermediates of the dye could not be mineralized under insufficient dissolved oxygen level. In the aspect of electricity generation, the maximum short circuit current (0.0041 mA cm-2) and power density (0.00028 mW cm-2) of the air purged photocatalytic fuel cell was obviously higher than that with nitrogen purging (0.0015 mA cm-2and 0.00008 mW cm-2).
    Matched MeSH terms: Oxygen/chemistry*
  20. Performance evaluation and kinetic modeling of down-flow high-rate anaerobic bioreactors for poultry slaughterhouse wastewater treatment
    Njoya M, Basitere M, Ntwampe SKO, Lim JW
    Environ Sci Pollut Res Int, 2020 Nov 04.
    PMID: 33145736 DOI: 10.1007/s11356-020-11397-5
    In this study, the treatment of poultry slaughterhouse wastewater (PSW) was evaluated using two new down-flow high-rate anaerobic bioreactor systems (HRABS), including the down-flow expanded granular bed reactor (DEGBR) and the static granular bed reactor (SGBR). These two bioreactors have demonstrated a good performance for the treatment of PSW with removal percentages of the biochemical oxygen demand (BOD5), the chemical oxygen demand (COD), and fats, oil, and grease (FOG) exceeding 95% during peak performance days. This performance of down-flow HRABS appears as a breakthrough in the field of anaerobic treatment of medium to high-strength wastewater because down-flow anaerobic bioreactors have been neglected for the high-rate anaerobic treatment of such wastewater due to the success of up-flow anaerobic reactors such as the UASB and the EGSB as a result of the granulation of a consortium of anaerobic bacteria required for efficient anaerobic digestion and biogas production. Hence, to promote the recourse to such technologies and provide further explanation to their performance, this study approached the kinetic analysis of these two down-flow HRABS using the modified Stover-Kincannon and the Grau second-order multi-component substrate models. From a comparison between the two models investigated, the modified Stover-Kincannon model provided the best prediction for the concentration of the substrate in the effluent from the two HRABS. This analysis led to the determination of the kinetic parameters of the two models that can be used for the design of the two HRABS and the prediction of the performance of the SGBR and DEGBR. The kinetic parameters determined using the Modified Stover-Kincannon were Umax = 40.5 gCOD/L.day and KB = 47.3 gCOD/L.day for the DEGBR and Umax = 33.6 gCOD/L.day and KB = 44.9 gCOD/L.day for the SGBR; while, using the Grau second-order model, the kinetic models determined were a = 0.058 and b = 1.112 for the DEGBR and a = 0.135 and b = 1.33 for the SGBR.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
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