Displaying publications 81 - 100 of 1088 in total

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  1. Zhang C, Chen WH, Ho SH, Zhang Y, Lim S
    Bioresour Technol, 2023 Oct;386:129531.
    PMID: 37473787 DOI: 10.1016/j.biortech.2023.129531
    This study performs the comparative advantage analysis of oxidative torrefaction of corn stalks to investigate the advantages of oxidative torrefaction for biochar fuel property upgrading. The obtained results indicate that oxidative torrefaction is more efficient in realizing mass loss and energy density improvement, as well as elemental carbon accumulation and surface functional groups removal, and thus leads to a better fuel property. The maximum values of relative mass loss, higher heating value, enhancement factor, and energy yield are 3.00, 1.10, 1.03, and 0.87, respectively. The relative elemental carbon, hydrogen, and oxygen content ranges are 1.30-3.10, 1.50-3.30, and 2.00-6.80, respectively. In addition, an excellent linear distribution is obtained between the comprehensive pyrolysis index and torrefaction severity index, with elemental carbon and oxygen component variation stemming from pyrolysis performance correlating to the elemental component and valance.
    Matched MeSH terms: Oxygen
  2. Zakaria SNF, Aziz HA, Mohamad M, Mohamad HM, Sulaiman MF
    Water Environ Res, 2023 Nov;95(11):e10941.
    PMID: 37828655 DOI: 10.1002/wer.10941
    Malaysia encounters a consistent rise in the generation of solid waste and leachate on a daily basis. It should also be noted that leachate has a low degree of biodegradability (BOD5 /chemical oxygen demand [COD]), as shown by its BOD5 /COD ratio. Its high toxicity levels significantly threaten the environment, water bodies, and human well-being. High concentrations of COD, color, and ammoniacal nitrogen (NH3 -N) in leachate prevent this wastewater from being allowed to be discharged directly into the water body. Therefore, an effective process to remove the pollutant is desired. The aims of this study are to investigate the performance of ozonation with two metallic compounds, ZrCl4 and SnCl4 , and optimize their performance using response surface methodology (RSM). In this study, the performance of ozonation with ZrCl4 (O3 /ZrCl4 ) recorded better pollutant removals compared with the ozonation with tin tetrachloride (O3 /SnCl4 ), as seen in the removals of 99.8%, 93.5%, and 46.3% for color, COD, and NH3 -N, respectively. These removals were achieved by following the experimental model (optimum experiment condition) generated by RSM at O3 dosage of 31 g/m3 , COD and ZrCl4 dosage ratio (COD, mg/L/ZrCl4 , mg/L) of 1:1.35, with the pH solution of 8.78 and reaction time of 89 min. The R2 of each parameter for this model was recorded as 0.999 (COD), 0.999 (color), and 0.998 (NH3 -N), respectively. These data indicated that the model is well fitted as the predicted data by statistical calculation and in good agreement with the actual data. PRACTITIONER POINTS: The performance of O3 /ZrCl4 and O3 /SnCl4 was examined for remediate stabilized landfill leachate. The performance of O3 /ZrCl4 and O3 /SnCl4 was optimized using RSM, and a set of experimental models was generated and tested. O3 /ZrCl4 recorded the higher removal of COD, color, and NH3 -N compared with O3 /SnCl4 . At best condition, both methods recorded removal as 89% to 99.8% of pollutants in leachate and product clear effluent. This finding gives a new approach to treat landfill leachate effectively and efficiently.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  3. Han M, Zhu T, Liang J, Wang H, Zhu C, Lee Binti Abdullah A, et al.
    Environ Int, 2024 Jan;183:108380.
    PMID: 38141489 DOI: 10.1016/j.envint.2023.108380
    Gastrointestinal diseases exert a profound impact on global health, leading to millions of healthcare interventions and a significant number of fatalities annually. This, coupled with escalating healthcare expenditures, underscores the need for identifying and addressing potential exacerbating factors. One emerging concern is the pervasive presence of microplastics and nano-plastics in the environment, largely attributed to the indiscriminate usage of disposable plastic items. These nano-plastics, having infiltrated our food chain, pose a potential threat to gastrointestinal health. To understand this better, we co-cultured human gastric fibroblasts (HGF) with polystyrene nano-plastics (PS-NPs) of diverse sizes (80, 500, 650 nm) and meticulously investigated their cellular responses over a 24-hour period. Our findings revealed PS particles were ingested by the cells, with a notable increase in ingestion as the particle size decreased. The cellular death induced by these PS particles, encompassing both apoptosis and necrosis, showcased a clear dependence on both the particle size and its concentration. Notably, the larger PS particles manifested more potent cytotoxic effects. Further analysis indicated a concerning reduction in cellular membrane potential, alongside a marked increase in ROS levels upon PS particles exposure. This suggests a significant disruption of mitochondrial function and heightened oxidative stress. The larger PS particles were especially detrimental in causing mitochondrial dysfunction. In-depth exploration into the PS particles impact on genes linked with the permeability transition pore (PTP) elucidated that these PS particles instigated an internal calcium rush. This surge led to a compromise in the mitochondrial membrane potential, which in tandem with raised ROS levels, further catalyzed DNA damage and initiated cell death pathways. In essence, this study unveils the intricate mechanisms underpinning cell death caused by PS particles in gastric epithelial cells and highlighting the implications of PS particles on gastrointestinal health. The revelations from this research bear significant potential to shape future healthcare strategies and inform pertinent environmental policies.
    Matched MeSH terms: Reactive Oxygen Species
  4. Song J, Farhadi A, Tan K, Lim L, Tan K
    Sci Total Environ, 2024 May 20;926:172056.
    PMID: 38552980 DOI: 10.1016/j.scitotenv.2024.172056
    Dissolved oxygen (DO) is an important parameter that affects the biology, physiology, and immunology of aquatic animals. In recent decades, DO levels in the global oceans have sharply decreased, partly due to an increase in atmospheric carbon dioxide, temperature, and anthropogenic nutrient loads. Although there have been many reports on the effects of hypoxia on the survival, growth, behavior, and immunity of bivalves, this information has not been well organized. Therefore, this article provides a comprehensive review of the effects of hypoxia on bivalves. In general, hypoxia negatively impacts the food consumption rate and assimilation efficiency, as well as increasing respiration rates in many bivalves. As a result, it reduces the energy allocation for bivalve growth, shell formation, and reproduction. In severe cases, prolonged exposure to hypoxia can result in mass mortality in bivalves. Moreover, hypoxia also has adverse effects on the immunity and response of bivalves to predators, including decreased burial depths, sensitivity to predators, impairment of byssus production, and negatively impacts on the integrity, strength, and composition of bivalve shells. The tolerance of bivalves to hypoxia largely depends on size and species, with larger bivalves being more susceptible to hypoxia and intertidal species being relatively more tolerant to hypoxia. The information in this article is very useful for elucidating the current research status of hypoxia on bivalves and determining future research directions.
    Matched MeSH terms: Oxygen
  5. Abdullah SNS, Subramaniam KA, Muhamad Zamani ZH, Sarchio SNE, Md Yasin F, Shamsi S
    Molecules, 2022 Jul 14;27(14).
    PMID: 35889367 DOI: 10.3390/molecules27144493
    Curcumin (CUR) has been studied for its biomedical applications due to its active biological properties. However, CUR has limitations such as poor solubility, low bioavailability, and rapid degradation. Thus, CUR was nanoformulated with the application of polymeric micelle. Previous studies of CUR-loaded Pluronic F127 nanoformulation (NanoCUR) were generally prioritized toward cancer cells and its therapeutic values. There are reports that emphasize the toxicity of CUR, but reports on the toxicity of NanoCUR on embryonic developmental stages is still scarce. The present study aims to investigate the toxicity effects of NanoCUR on the embryonic development of zebrafish (Danio rerio). NanoCUR was synthesized via thin film hydration method and then characterized using DLS, UV-Vis, FTIR, FESEM, and XRD. The toxicity assessment of NanoCUR was conducted using zebrafish embryos, in comparison to native CUR, as well as Pluronic F127 (PF) as the controls, and ROS assay was further carried out. It was revealed that NanoCUR showed an improved toxicity profile compared to native CUR. NanoCUR displayed a delayed toxicity response and showed a concentration- and time-dependent toxicity response. NanoCUR was also observed to generate a significantly low reactive oxygen species (ROS) compared to native CUR in ROS assay. Overall, the results obtained highlight the potential of NanoCUR to be developed in clinical settings due to its improved toxicity profile compared to CUR.
    Matched MeSH terms: Reactive Oxygen Species
  6. Hébert-Losier K, Zinner C, Platt S, Stöggl T, Holmberg HC
    Sports Med, 2017 Feb;47(2):319-342.
    PMID: 27334280 DOI: 10.1007/s40279-016-0573-2
    BACKGROUND: Sprint events in cross-country skiing are unique not only with respect to their length (0.8-1.8 km), but also in involving four high-intensity heats of ~3 min in duration, separated by a relatively short recovery period (15-60 min).

    OBJECTIVE: Our aim was to systematically review the scientific literature to identify factors related to the performance of elite sprint cross-country skiers.

    METHODS: Four electronic databases were searched using relevant medical subject headings and keywords, as were reference lists, relevant journals, and key authors in the field. Only original research articles addressing physiology, biomechanics, anthropometry, or neuromuscular characteristics and elite sprint cross-country skiers and performance outcomes were included. All articles meeting inclusion criteria were quality assessed. Data were extracted from each article using a standardized form and subsequently summarized.

    RESULTS: Thirty-one articles met the criteria for inclusion, were reviewed, and scored an average of 66 ± 7 % (range 56-78 %) upon quality assessment. All articles except for two were quasi-experimental, and only one had a fully-experimental research design. In total, articles comprised 567 subjects (74 % male), with only nine articles explicitly reporting their skiers' sprint International Skiing Federation points (weighted mean 116 ± 78). A similar number of articles addressed skating and classical techniques, with more than half of the investigations involving roller-skiing assessments under laboratory conditions. A range of physiological, biomechanical, anthropometric, and neuromuscular characteristics was reported to relate to sprint skiing performance. Both aerobic and anaerobic capacities are important qualities, with the anaerobic system suggested to contribute more to the performance during the first of repeated heats; and the aerobic system during subsequent heats. A capacity for high speed in all the following instances is important for the performance of sprint cross-country skiers: at the start of the race, at any given point when required (e.g., when being challenged by a competitor), and in the final section of each heat. Although high skiing speed is suggested to rely primarily on high cycle rates, longer cycle lengths are commonly observed in faster skiers. In addition, faster skiers rely on different technical strategies when approaching peak speeds, employ more effective techniques, and use better coordinated movements to optimize generation of propulsive force from the resultant ski and pole forces. Strong uphill technique is critical to race performance since uphill segments are the most influential on race outcomes. A certain strength level is required, although more does not necessarily translate to superior sprint skiing performance, and sufficient strength-endurance capacities are also of importance to minimize the impact and accumulation of fatigue during repeated heats. Lastly, higher lean mass does appear to benefit sprint skiers' performance, with no clear advantage conferred via body height and mass.

    LIMITATIONS: Generalization of findings from one study to the next is challenging considering the array of experimental tasks, variables defining performance, fundamental differences between skiing techniques, and evolution of sprint skiing competitions. Although laboratory-based measures can effectively assess on-snow skiing performance, conclusions drawn from roller-skiing investigations might not fully apply to on-snow skiing performance. A low number of subjects were females (only 17 %), warranting further studies to better understand this population. Lastly, more training studies involving high-level elite sprint skiers and investigations pertaining to the ability of skiers to maintain high-sprint speeds at the end of races are recommended to assist in understanding and improving high-level sprint skiing performance, and resilience to fatigue.

    CONCLUSIONS: Successful sprint cross-country skiing involves well-developed aerobic and anaerobic capacities, high speed abilities, effective biomechanical techniques, and the ability to develop high forces rapidly. A certain level of strength is required, particularly ski-specific strength, as well as the ability to withstand fatigue across the repeated heats of sprint races. Cross-country sprint skiing is demonstrably a demanding and complex sport, where high-performance skiers need to simultaneously address physiological, biomechanical, anthropometric, and neuromuscular aspects to ensure success.

    Matched MeSH terms: Oxygen Consumption*
  7. Amirul Alam M, Juraimi AS, Rafii MY, Hamid AA, Aslani F, Alam MZ
    Food Chem, 2015 Feb 15;169:439-47.
    PMID: 25236249 DOI: 10.1016/j.foodchem.2014.08.019
    Dry matter (DM), total phenolics, flavonoids, carotenoid contents, and antioxidant activity of 12 purslane accessions were investigated against five levels of salinity (0, 8, 16, 24 and 32dSm(-1)). In untreated plants, the DM contents ranged between 8.0-23.4g/pot; total phenolics contents (TPC) between 0.96-9.12mgGAEg(-1)DW; total flavonoid contents (TFC) between 0.15-1.44mgREg(-1)DW; and total carotenoid contents (TCC) between 0.52BCEg(-1)DW. While FRAP activity ranged from 8.64-104.21mgTEg(-1)DW (about 12-fold) and DPPH activity between 2.50-3.30mgmL(-1) IC50 value. Different levels of salinity treatment resulted in 8-35% increases in TPC; about 35% increase in TFC; and 18-35% increases in FRAP activity. Purslane accessions Ac4, Ac5, Ac6 and Ac8 possessed potentials for salinity-induced augmented production of bioactive compounds which in turn can be harnessed for possible human health benefits.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  8. Manickam S, Abidin Nb, Parthasarathy S, Alzorqi I, Ng EH, Tiong TJ, et al.
    Ultrason Sonochem, 2014 Jul;21(4):1519-26.
    PMID: 24485395 DOI: 10.1016/j.ultsonch.2014.01.002
    Palm oil mill effluent (POME) is a highly contaminating wastewater due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Conventional treatment methods require longer residence time (10-15 days) and higher operating cost. Owing to this, finding a suitable and efficient method for the treatment of POME is crucial. In this investigation, ultrasound cavitation technology has been used as an alternative technique to treat POME. Cavitation is the phenomenon of formation, growth and collapse of bubbles in a liquid. The end process of collapse leads to intense conditions of temperature and pressure and shock waves which assist various physical and chemical transformations. Two different ultrasound systems i.e. ultrasonic bath (37 kHz) and a hexagonal triple frequency ultrasonic reactor (28, 40 and 70 kHz) of 15 L have been used. The results showed a fluctuating COD pattern (in between 45,000 and 60,000 mg/L) while using ultrasound bath alone, whereas a non-fluctuating COD pattern with a final COD of 27,000 mg/L was achieved when hydrogen peroxide was introduced. Similarly for the triple frequency ultrasound reactor, coupling all the three frequencies resulted into a final COD of 41,300 mg/L compared to any other individual or combination of two frequencies. With the possibility of larger and continuous ultrasonic cavitational reactors, it is believed that this could be a promising and a fruitful green process engineering technique for the treatment of POME.
    Matched MeSH terms: Biological Oxygen Demand Analysis*
  9. Koh MK, Sathiamurthy E, Suratman S, Tahir NM
    Environ Monit Assess, 2012 Dec;184(12):7653-64.
    PMID: 22302401
    Influences of river hydrodynamic behaviours on hydrochemistry (salinity, pH, dissolved oxygen saturations and dissolved phosphorus) were evaluated through high spatial and temporal resolution study of a sandbar-regulated coastal river. River hydrodynamic during sandbar-closed event was characterized by minor dependency on tidal fluctuations, very gradual increase of water level and continual low flow velocity. These hydrodynamic behaviours established a hydrochemistry equilibrium, in which water properties generally were characterized by virtual absence of horizontal gradients while vertical stratifications were significant. In addition, the river was in high trophic status as algae blooms were visible. Conversely, river hydrodynamic in sandbar-opened event was tidal-controlled and showed higher flow velocity. Horizontal gradients of water properties became significant while vertically more homogenised and with lower trophic status. In essence, this study reveals that estuarine sandbar directly regulates river hydrodynamic behaviours which in turn influences river hydrochemistry.
    Matched MeSH terms: Oxygen/analysis
  10. Fulazzaky MA
    Environ Monit Assess, 2013 Jun;185(6):4721-34.
    PMID: 23001555 DOI: 10.1007/s10661-012-2899-z
    Biochemical oxygen demand (BOD) of the leachates originally from the different types of landfill sites was studied based on the data measured using the two manometric methods. The measurements of BOD using the dilution method were carried out to assess the typical physicochemical and biological characteristics of the leachates together with some other parameters. The linear regression analysis was used to predict rate constants for biochemical reactions and ultimate BOD values of the different leachates. The rate of a biochemical reaction implicated in microbial biodegradation of pollutants depends on the leachate characteristics, mass of contaminant in the leachate, and nature of the leachate. Character of leachate samples for BOD analysis of using the different methods may differ significantly during the experimental period, resulting in different BOD values. This work intends to verify effect of the different dilutions for the manometric method tests on the BOD concentrations of the leachate samples to contribute to the assessment of reaction rate and microbial consumption of oxygen.
    Matched MeSH terms: Biological Oxygen Demand Analysis/methods*
  11. Achari VM, Nguan HS, Heidelberg T, Bryce RA, Hashim R
    J Phys Chem B, 2012 Sep 27;116(38):11626-34.
    PMID: 22967067
    Glycolipids form materials of considerable potential for a wide range of surfactant and thin film applications. Understanding the effect of glycolipid covalent structure on the properties of their thermotropic and lyotropic assemblies is a key step toward rational design of new glycolipid-based materials. Here, we perform molecular dynamics simulations of anhydrous bilayers of dodecyl β-maltoside, dodecyl β-cellobioside, dodecyl β-isomaltoside, and a C(12)C(10) branched β-maltoside. Specifically, we examine the consequences of chain branching and headgroup identity on the structure and dynamics of the lamellar assemblies. Chain branching of the glycolipid leads to measurable differences in the dimensions and interactions of the lamellar assembly, as well as a more fluid-like hydrophobic chain region. Substitution of the maltosyl headgroup of βMal-C(12) by an isomaltosyl moiety leads to a significant decrease in bilayer spacing as well as a markedly altered pattern of inter-headgroup hydrogen bonding. The distinctive simulated structures of the two regioisomers provide insight into the difference of ~90 °C in their observed clearing temperatures. For all four simulated glycolipid systems, with the exception of the sn-2 chain of the branched maltoside, the alkyl chains are ordered and exhibit a distinct tilt, consistent with recent crystallographic analysis of a branched chain Guerbet glycoside. These insights into structure-property relationships from simulation provide an important molecular basis for future design of synthetic glycolipid materials.
    Matched MeSH terms: Oxygen/chemistry
  12. Al-Amri A, Salim MR, Aris A
    Water Sci Technol, 2011;64(7):1398-405.
    PMID: 22179635 DOI: 10.2166/wst.2011.421
    A study has been carried out to define the effect of drastic temperature changes on the performance of lab-scale hollow-fibre MBR in treating municipal wastewater at a flux of 10 L m(-2) h(-1) (LMH). The objectives of the study were to estimate the activated sludge properties, the removal efficiencies of COD and NH(3)-N and the membrane fouling tendency under critical conditions of drastic temperature changes (23, 33, 42 & 33 °C) and MLSS concentration ranged between 6,382 and 8,680 mg/L. The study exhibited that the biomass reduction, the low sludge settleability and the supernatant turbidity were results of temperature increase. The temperature increase led to increase in SMP carbohydrate and protein, and to decrease in EPS carbohydrate and protein. The BRE of COD dropped from 80% at 23 °C to 47% at 42 °C, while the FRE was relatively constant at about 90%. Both removal efficiencies of NH(3)-N trended from about 100% at 33 °C to less than 50% at 42 °C. TMP and BWP ascended critically with temperature increase up to 336 and 304 mbar respectively by the end of the experiment. The values of suspended solids (SS) and the turbidity in the final effluent were negligible. The DO in the mixed liquor was varying with temperature change, while the pH was within the range of 6.7-8.3.
    Matched MeSH terms: Oxygen/metabolism
  13. Chan YK, Khan ZH
    Acta Anaesthesiol Taiwan, 2011 Dec;49(4):154-8.
    PMID: 22221689 DOI: 10.1016/j.aat.2011.11.002
    Hemodynamic monitoring provides us with refined details about the cardiovascular system. In spite of increased availability of the monitoring process and monitoring equipment, hemodynamic monitoring has not significantly improved survival outcome. Care providers should be cognizant of the role of the cardiovascular system and its importance in oxygen delivery to the cells in order to sustain life. Effective hemodynamic monitoring should be able to delineate how well the system is performing in carrying out this role. Different hemodynamic monitors serve in this role to a different extent; some provide very little information on this. The cardiovascular system is only one of the many systems that need to function optimally for survival; others of equal importance include the integrity of the airway, the breathing process, the adequacy of hemoglobin level, and the health of the tissue bed, especially in the brain and the heart. Advances in hemodynamic monitoring with focus on oxygen delivery at the cellular level may ultimately provide the edge to effective monitoring that can impact outcome.
    Matched MeSH terms: Oxygen/metabolism
  14. Ramasamy R, Maqbool M, Mohamed AL, Noah RM
    Cell Immunol, 2010;263(2):230-4.
    PMID: 20471005 DOI: 10.1016/j.cellimm.2010.04.004
    Neutrophils play a significant role in maintaining the integrity of innate immunity via their potent respiratory burst activity. However, the uncontrolled activation of respiratory burst in neutrophils also attributes to chronic diseases such as primary hypertension and atherosclerosis. In our study, we have investigated the activation of respiratory burst function of neutrophils harvested from essential hypertensive patients. In the presence of stimuli PMA and opsonized zymosan (OZ), hypertensive patients' neutrophils secrete significantly higher amount of superoxide anions compared to normotensive control. Although the magnitude of activation varies between both groups, yet the kinetics of activation is similar. When normotensive control's neutrophils were pre-treated with hypertensive serum, the cells failed to migrate toward fMLP which indicates the impairment of the migration property. In conclusion, the respiratory burst activity of neutrophils is affected by hypertension and their elevated superoxide anions production could be an aggravating factor in hypertension-related complication.
    Matched MeSH terms: Reactive Oxygen Species/blood
  15. Khabibor Rahman N, Bakar MZ, Hekarl Uzir M, Harun Kamaruddin A
    Math Biosci, 2009 Apr;218(2):130-7.
    PMID: 19563738 DOI: 10.1016/j.mbs.2009.01.007
    A one-dimensional biofilm model was developed based on the basic principle of conservation of mass. Three simple, generic processes were combined in the model which includes microbial growth, diffusive and convective mass transport. The final model could generate a quantitative description of the relationship between the microbial growth and the consumption of substrate (oxygen) within the fixed biofilm thickness. Mass transfer resistance contributes large influence on the substrates and microbial concentration across the biofilm thickness due to the effect of biofilm structure.
    Matched MeSH terms: Oxygen/metabolism*
  16. Ng SL, Seng CE, Lim PE
    Chemosphere, 2009 Jun;75(10):1392-400.
    PMID: 19307013 DOI: 10.1016/j.chemosphere.2009.02.049
    The bioregeneration efficiencies of powdered activated carbon (PAC) and pyrolyzed rice husk loaded with phenol and p-nitrophenol were quantified by oxygen uptake measurements using the respirometry technique in two approaches: (i) simultaneous adsorption and biodegradation and (ii) sequential adsorption and biodegradation. It was found that the applicability of the simultaneous adsorption and biodegradation approach was constrained by the requirement of adsorption preceding biodegradation in order to determine the initial adsorbent loading accurately. The sequential adsorption and biodegradation approach provides a good estimate of the upper limit of the bioregeneration efficiency for the loaded adsorbent in the simultaneous adsorption and biodegradation processes. The results showed that the mean bioregeneration efficiencies for PAC loaded with phenol and p-nitrophenol, respectively, obtained using the two approaches were in good agreement.
    Matched MeSH terms: Oxygen/metabolism
  17. Abd-Aziz S, Fernandez CC, Salleh MM, Illias RM, Hassan MA
    Appl Biochem Biotechnol, 2008 Aug;150(2):193-204.
    PMID: 18633736 DOI: 10.1007/s12010-008-8140-4
    Shrimps have been a popular raw material for the burgeoning marine and food industry contributing to increasing marine waste. Shrimp waste, which is rich in organic compounds is an abundant source of chitin, a natural polymer of N-acetyl-D-glucosamine (GluNac), a reducing sugar. For this respect, chitinase-producing fungi have been extensively studied as biocontrol agents. Locally isolated Trichoderma virens UKM1 was used in this study. The effect of agitation and aeration rates using colloidal chitin as control substrate in a 2-l stirred tank reactor gave the best agitation and aeration rates at 200 rpm and 0.33 vvm with 4.1 U/l per hour and 5.97 U/l per hour of maximum volumetric chitinase activity obtained, respectively. Microscopic observations showed shear sensitivity at higher agitation rate of the above system. The oxygen uptake rate during the highest chitinase productivity obtained using sun-dried ground shrimp waste of 1.74 mg of dissolved oxygen per gram of fungal biomass per hour at the kappaL a of 8.34 per hour.
    Matched MeSH terms: Oxygen/metabolism*
  18. Wong SS, Teng TT, Ahmad AL, Zuhairi A, Najafpour G
    J Hazard Mater, 2006 Jul 31;135(1-3):378-88.
    PMID: 16431022
    The flocculation performances of nine cationic and anionic polyacrylamides with different molecular weights and different charge densities in the treatment of pulp and paper mill wastewater have been studied. The experiments were carried out in jar tests with the polyacrylamide dosages range of 0.5-15 mg l(-1), rapid mixing at 200 rpm for 2 min, followed by slow mixing at 40 rpm for 15 min and settling time of 30 min. The effectiveness of the polyacrylamides was measured based on the reduction of turbidity, the removal of total suspended solids (TSS) and the reduction of chemical oxygen demand (COD). Cationic polyacrlyamide Organopol 5415 with very high molecular weight and low charge density is found to give the highest flocculation efficiency in the treatment of the paper mill wastewater. It can achieve 95% of turbidity reduction, 98% of TSS removal, 93% of COD reduction and sludge volume index (SVI) of 14 ml g(-1) at the optimum dosage of 5 mg l(-1). SVI values of less than 70 m lg(-1) are found for all polyacrylamide at their respective optimum dosage. Based on the cost evaluation, the use of the polyacrylamides is economically feasible to treat the pulp and paper mill wastewaters. This result suggests that single-polymer system can be used alone in the coagulation-flocculation process due to the efficiency of the polyacrylamide. Sedimentation of the sludge by gravity thickening with settling time of 30 min is possible based on the settling characteristics of the sludge produced by Organopol 5415 that can achieve 91% water recovery and 99% TSS removal after 30 min settling.
    Matched MeSH terms: Oxygen/chemistry
  19. Sommer SG, Mathanpaal G, Dass GT
    Environ Technol, 2005 Mar;26(3):303-12.
    PMID: 15881027
    On commercial pig production farms in South East (SE) Asia, the liquid effluent is often discharged into rivers. The discharge is a hazard to the environment and to the health of people using water from the river either for consumption or for irrigation. Therefore, a simple percolation biofilter for treatment of the liquid effluent was developed. Pig slurry was treated in test-biofilters packed with different biomass for the purpose of selecting the most efficient material, thereafter the efficiency of the biofilter was examined at farm scale with demo biofilters using the most efficient material. The effect of using "Effective Microorganisms" (EM) added to slurry that was treated with biofilter material mixed with Glenor KR+ was examined. Slurry treatment in the test-biofilters indicated that rice straw was better than coconut husks, wood shavings, rattan strips and oil palm fronds in reducing BOD. Addition of EM and Glenor KR+ to slurry and biofilter material, respectively, had no effect on the temperature of the biofilter material or on the concentrations of organic and inorganic components of the treated slurry. The BOD of slurry treated in test biofilters is reduced to between 80 and 637 mg O2 I(-1) and in the demo biofilter to between 3094 and 3376 mg O2 l(-1). The concentration of BOD in the effluent is related to the BOD in the slurry being treated and the BOD concentration in slurry treated in test biofilters was lower than BOD of slurry treated in demo biofilters. The demo biofilter can reduce BOD to between 52 an 56% of the original value, and TSS, COD (chemical oxygen demand) and ammonium (NH4+) to 41-55% of the original slurry. The treated effluent could not meet the standards for discharge to rivers. The composted biofilter material has a high content of nitrogen and phosphorus; consequently, the fertilizer value of the compost is high. The investments costs were 123 US dollar per SPP which has to be reduced if this method should be a treatment option in practise.
    Matched MeSH terms: Oxygen/metabolism
  20. Thung WE, Ong SA, Ho LN, Wong YS, Ridwan F, Oon YL, et al.
    Bioresour Technol, 2015 Dec;197:284-8.
    PMID: 26342340 DOI: 10.1016/j.biortech.2015.08.078
    Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the feasibility of the bioreactor for decolorization of Acid Orange 7 (AO7) and electricity generation simultaneously. The performance of UFML MFC was evaluated in terms of voltage output, chemical oxygen demand (COD) and color removal efficiency by varying the concentration of AO7 in synthetic wastewater. The results shown the voltage generation and COD removal efficiency decreased as the initial AO7 concentration increased; this indicates there is electron competition between anode and azo dye. Furthermore, there was a phenomenon of further decolorization at cathode region which indicates the oxygen and azo dye are both compete as electron acceptor. Based on the UV-visible spectra analysis, the breakdown of the azo bond and naphthalene compound in AO7 were confirmed. These findings show the capability of integrated UFML MFC in azo dye wastewater treatment and simultaneous electricity generation.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
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