Displaying publications 541 - 560 of 1088 in total

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  1. Fatema K, Wan Maznah WO, Isa MM
    Trop Life Sci Res, 2014 Dec;25(2):1-19.
    PMID: 27073596 MyJurnal
    In this study, factor analysis (FA) was applied to extract the hidden factors responsible for water quality variations during both wet and dry seasons. Water samples were collected from six sampling stations (St. 1 Lalang River, St. 2 Semeling River, St. 3 Jagung River, St. 4 Teluk Wang River, St. 5 Gelam River and St. 6 Derhaka River) in the Merbok estuary, Malaysia from January to December 2011; the samples were further analysed in the laboratory. Correlation analysis of the data sets showed strong correlations between the parameters. Nutrients such as nitrate (NO3 (-)), nitrite (NO2 (-)), ammonia (NH3) and phosphate (PO4 (3-)) were determined to be critical indicators of water quality throughout the year. Influential water quality parameters during the wet season were conductivity, salinity, biochemical oxygen demand (BOD), dissolved oxygen (DO) and chlorophyll a (Chla), whereas total suspended solid (TSS) and pH were critical water quality indicators during the dry season. The Kruskal-Wallis H test showed that water quality parameters were significantly different among the sampling months and stations (p<0.05), and Mann-Whitney U tests further revealed that the significantly different parameters were temperature, pH, DO, TSS, NO2 (-) and BOD (p<0.01), whereas salinity, conductivity, NO3 (-), PO4 (3-), NH3 and Chla were not significantly different (p>0.05). Water quality parameters in the estuary varied on both temporal and spatial scales and these results may serve as baseline information for estuary management, specifically for the Merbok estuary.
    Matched MeSH terms: Oxygen
  2. Asma Liyana Shaari, Misni Surif, Faazaz Abd. Latiff, Wan Maznah Wan Omar, Mohd Noor Ahmad
    Trop Life Sci Res, 2011;22(1):-.
    MyJurnal
    Many reports have revealed that the abundance of microalgae in shrimp ponds vary with changes in environmental factors such as light, temperature, pH, salinity and nutrient level throughout a shrimp culture period. In this study, shrimp cultivation period was divided into three stages (initial = week 0–5, mid = week 6–10 and final = week 11–15). Physical and chemical parameters throughout the cultivation period were studied and species composition of microalgae was monitored. Physical parameters were found to
    fluctuate widely with light intensity ranging between 182.23–1278 µmol photon m–2s–1, temperature between 29.56ºC –31.59ºC, dissolved oxygen (DO) between 4.56–8.21 mg/l, pH between 7.65–8.49 and salinity between 20‰–30‰. Ammonium (NH4+-N), nitrite (NO2– -N), nitrate (NO3– -N), and orthophosphate (PO43– -P) concentrations in the pond at all cultivation stages ranged from 0.017 to 0.38 mg/l, 0.24 to 2.12 mg/l, 0.06 to 0.98 mg/l and 0.16 to 1.93 mg/l respectively. Statistical test (ANOVA) showed that there were no significant difference (p
    Matched MeSH terms: Oxygen
  3. Shaari AL, Surif M, Latiff FA, Omar WM, Ahmad MN
    Trop Life Sci Res, 2011 May;22(1):51-69.
    PMID: 24575209
    Many reports have revealed that the abundance of microalgae in shrimp ponds vary with changes in environmental factors such as light, temperature, pH, salinity and nutrient level throughout a shrimp culture period. In this study, shrimp cultivation period was divided into three stages (initial = week 0-5, mid = week 6-10 and final = week 11-15). Physical and chemical parameters throughout the cultivation period were studied and species composition of microalgae was monitored. Physical parameters were found to fluctuate widely with light intensity ranging between 182.23-1278 μmol photon m(-2)s(-1), temperature between 29.56°C -31.59°C, dissolved oxygen (DO) between 4.56-8.21 mg/l, pH between 7.65-8.49 and salinity between 20‰-30‰. Ammonium (NH4 (+)-N), nitrite (NO2 (-)-N), nitrate (NO3 (-)-N), and orthophosphate (PO4 (3-)-P) concentrations in the pond at all cultivation stages ranged from 0.017 to 0.38 mg/l, 0.24 to 2.12 mg/l, 0.06 to 0.98 mg/l and 0.16 to 1.93 mg/l respectively. Statistical test (ANOVA) showed that there were no significant difference (p<0.05) in nutrients concentrations among the cultivation stages. All nutrients concentrations however were still in the tolerable level and safe for shrimp culture. The chlorophyll a contents were found to range from 5.03±2.17 to 32.61±0.35 μg/l throughout the cultivation period. A total of 19 microalgae species were found in the shrimp pond, with diatoms contributing up to 72% of the species followed by Chlorophyta (11%) and Cyanophyta (11%). However, weekly species abundance varied through the study period. At the initial stage, when there were no shrimps in the pond, Anabaena spp. and Oscillatoria spp. (Cyanophyta) were the dominant species, followed by Chlorella sp. and Dunaliella sp. (Chlorophyta). When shrimps were introduced into the pond, Amphora sp., Navicula sp. Gyrosigma sp. and Nitzschia sp. (diatoms) started to exist. At the middle and towards the final stage of the shrimp culture period diatoms were the dominant species. The Chlorophyta (Chlorella sp.) domination took place only twice, which was at week 2 and 13. The absence of some of the coastal water microalgae species in the shrimp pond was most likely due to the fact that they could not tolerate the physicochemical factors of harsh environment. In this study, Cylindrotheca closterium was regarded as the most tolerant species among the microalgae due to its ability to exist for 6 weeks out of the 15 weeks of cultivation.
    Matched MeSH terms: Oxygen
  4. Hiu JJ, Yap MKK
    Biochem Soc Trans, 2020 04 29;48(2):719-731.
    PMID: 32267491 DOI: 10.1042/BST20200110
    The phospholipase A2 (PLA2) and l-amino acid oxidase (LAAO) are two major enzymes found in the venoms from most snake species. These enzymes have been structurally and functionally characterised for their pharmacological activities. Both PLA2 and LAAO from different venoms demonstrate considerable cytotoxic effects on cancer cells via induction of apoptosis, cell cycle arrest and suppression of proliferation. These enzymes produce more pronounced cytotoxic effects in cancer cells than normal cells, thus they can be potential sources as chemotherapeutic agents. It is proposed that PLA2 and LAAO contribute to an elevated oxidative stress due to their catalytic actions, for instance, the ability of PLA2 to produce reactive oxygen species during lipolysis and formation of H2O2 from LAAO catalytic activity which consequently lead to cell death. Nonetheless, the cell-death signalling pathways associated with exposure to these enzymatic toxins are not fully elucidated yet. Here in this review, we will discuss the cytotoxic effects of PLA2 and LAAO in relationship to their catalytic mechanisms and the underlying mechanisms of cytotoxic actions.
    Matched MeSH terms: Reactive Oxygen Species
  5. Barathan M, Zulpa AK, Vellasamy KM, Mariappan V, Shivashekaregowda NKH, Ibrahim ZA, et al.
    In Vivo, 2021 8 20;35(5):2675-2685.
    PMID: 34410956 DOI: 10.21873/invivo.12551
    BACKGROUND/AIM: Isoniazid is an antibiotic used for the treatment of tuberculosis. Previously, we found that the isoniazid derivative (E)-N'-(2,3,4-trihydroxybenzylidene) isonicotinohydrazide (ITHB4) could be developed as novel antimycobacterial agent by lead optimization. We further explored the ability of this compound compared to zerumbone in inhibiting the growth of MCF-7 breast cancer cells.

    MATERIALS AND METHODS: Cytotoxicity was measured by the MTT assay and further confirmed via apoptosis, ROS, cell cycle, DNA fragmentation and cytokine assays.

    RESULTS: ITHB4 demonstrated a lower IC50 compared to zerumbone in inhibiting the proliferation of MCF-7 cells. ITHB4 showed no toxicity against normal breast and human immune cells. Apoptosis assay revealed that ITHB4, at a concentration equal to the IC50, induces apoptosis of MCF-7 cells and cell cycle arrest at the sub-G1 and G2/M phases. ITHB4 triggered accumulation of intracellular ROS and nuclear DNA fragmentation. Secretion of pro-inflammatory cytokines induced inflammation and potentially immunogenic cell death.

    CONCLUSION: ITHB4 has almost similar chemotherapeutic properties as zerumbone in inhibiting MCF-7 growth, and hence provide the basis for further experiments in animal models.

    Matched MeSH terms: Reactive Oxygen Species
  6. Affendi, A.F., Hasmaliza, M., Srimala, S.
    MyJurnal
    In these studies, cordierite was mechanically synthesized after a sol-gel process. The effect of milling time of cordierite was investigated. Aluminium nitrate nonahydrate, magnesium nitrate hexahydrate and tetraethylorthosilicate (TEOS) were used as starting materials. Gels obtained were mechanically activated in planetary ball mill by at 300rpm grinding speed and grinding time (15min, 30min, 45min and 60min). Powders produced were characterized by X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray (EDX). XRD analysis proved that α-cordierite was formed at lower temperature (1200°C) as compliment to without grinding, whereby it is formed at1300°C. FESEM analysis shows the size of the cordierite were in submicron scale. EDX analysis proved that magnesium, aluminium, silicon and oxygen are elements existed in cordierite.
    Matched MeSH terms: Oxygen
  7. Nurul Hanani, M.Z., Halimahton Zahrah, M.S., Zaibunnisa, A.H.
    MyJurnal
    This study was conducted to develop an edible coating containing combined hydrophilic (chitosan) and hydrophobic (palm stearin) components which demonstrated gas barrier and moisture barrier properties, respectively, to prolong the post harvest life of star fruits (Averrhoa carambola L.). The emulsions of chitosan (C) and palm stearin (S) were prepared by using different ratios of C:S which were 1:0, 1:1, 1;2, 1:3, 2:1, 3:1 and 0:1. Viscosity of emulsions was studied. The physicochemical properties of coated star fruits were also evaluated in terms of weight loss, firmness, visual appearance, oxygen concentration, carbon dioxide concentration and ethylene concentration during storage at room temperature (26-28˚C) for 18 days. The results obtained showed that coating reduced weight loss, maintained firmness and appearance, slowed down the production of respiratory gases and reduced ethylene production. The most recommended coating for star fruits was C:S of 1:1 ratio as it showed good water barrier and gas barrier properties and could extend the post harvest life of star fruits up to 20 days as compared to the control samples which had a post harvest life of 12 days.
    Matched MeSH terms: Oxygen
  8. Lai, S.C., Choy, Y.C.
    MyJurnal
    This was a prospective, randomized, double-blind study comparing the effect of remifentanil and fentanyl on cardiovascular responses from laryngoscopy and tracheal intubation. Forty-four ASA I or II patients aged between 18-65 yrs scheduled for elective surgery under general anaesthesia, were recruited and randomized into two groups. Each patient in Group R received remifentanil of 0.5 mcg/kg bolus over 30 seconds followed by an infusion of 0.25 mcg/kg/min and each patient in Group F received fentanyl of 2 mcg/kg bolus over 30 seconds followed by an infusion of normal saline. Anaesthesia was then induced with propofol, rocuronium and 2% sevoflurane with 100% oxygen. Cardiovascular changes were recorded every minute for 3 minutes after induction and 5 minutes after tracheal intubation. The heart rate remained stable throughout the induction and intubation period in both groups. None of the patients in the remifentanil group develop bradycardia. Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly lower in the fentanyl group at the 3rd minute post-induction and 5th minute post- intubation (p < 0.05). Diastolic blood pressure (DBP) in the fentanyl group was significantly lower at the 2nd and 3rd minute post-induction and 4th and 5th minute post-intubation (p < 0.05). The blood pressure remained stable for the remifentanil group throughout the induction and intubation period. Six patients (27.2%) in the fentanyl group and one patient (4.5%) in the remifentanil group experienced hypertension. Three patients (13.7%) from each group experienced hypotensive episodes. In conclusion, remifentanil 0.5 mcg/kg bolus followed by 0.25 mcg/kg/min infusion resulted in SBP, MAP and DBP remained slightly lower than baseline throughout the whole period but still consider stable, as these changes were not statistically significant.
    Matched MeSH terms: Oxygen
  9. Jacqueline, H.O.
    MyJurnal
    A retrospective survey was carried out in a neonatal unit to identify babies who required oxygen for more than the first 28 days of life and to determine the cause of their oxygen dependency. A total of 9173 neonates were admitted over a three year period. Approximately 750 were ventilated. Fifteen required oxygen for more than the first 28 days. Ten (67%) of these were due to bronchopulmonary dysplasia. 2 had upper airway complications of mechanical ventilation, one had recurrent apnoea, one had recurrent pneumonia, and one who did not require ventilation had chronic oxygen dependency of unknown cause. Bronchopulmonary dysplasia was the commonest cause of chronic oxygen dependency. The incidence was 1.5% of ventilated babies.
    Matched MeSH terms: Oxygen
  10. Vikram, M., Joseph, Leonard H., Kamaria, K.
    MyJurnal
    Emphysematous pyelonephritis is a form of infection of the kidney. Chest physiotherapy was executed on a 15-year-old girl who had complications such as secretion retention and pleural effusion following percutaneous pigtail nephrostomy in addition to oxygen therapy and medical management to promote respiratory functions. The processes to increase chest wall mobility includes particular passive stretching and mobilization. Chest mobility exercises composed of an intercostal stretch on a determined intercostal space using index fingers, thoracic rotation and anterior compression with stretching in sitting position to improve respiratory functions. These exercises were suggested to the patient as a regular daily treatment along with low-level incentive spirometry breathing exercises. Following 9th sessions of treatment patient demonstrated satisfactory improvement by means of increasing in chest expansion and reduction in dyspnea level without using supplemental oxygen. The results expressed a substantial clinical improvement in reduction of dyspnea level and improvement in chest expansion
    Matched MeSH terms: Oxygen
  11. MyJurnal
    Introduction: Pneumonia is the most common diagnosis made in hospitalised children. The Malaysian Clinical Practice Guidelines on pneumonia and respiratory tract infections provides a comprehensive guidance in the local context. We evaluated the documented assessment and management of children diagnosed with pneumonia admitted to the children’s ward, Hospital Batu Pahat against this guideline.
    Methods: We performed a retrospective analysis of hospital case notes for children admitted from January to May 2004.
    Results: Ninety six case notes were analysed. Most patients (84%) had at least four positive clinical features leading to the diagnosis of pneumonia. 92% met the guideline criteria for admission. Sp02 was performed for 58% on admission, and 58% with reading below 95% received supplemental oxygen. Throughout hospital stay, each patient had an average of four investigations (range: 1 – 12). Among 23 patients who had further investigations, justifications were only recorded in seven patients (30.4%), and changes in management resulted in 23%. The most common antibiotic prescribed was intravenous Penicillin (97 %). In 17 patients who met the guideline classification for severe pneumonia, none received the recommended antibiotic combination. The median time to fever resolution was 22 hours (range 2 – 268), and median hospital stay was 3 days (range 1 – 12).
    Conclusions: Although the quality of clinical assessment and antibiotic choices were acceptable, there was a failure to critically evaluate patients according to disease severity and initiate corresponding investigations and managements. Future efforts need to be directed at promoting further guideline adherence and the exercise of critical judgment in patient evaluation.
    Matched MeSH terms: Oxygen
  12. Fatin Azwa Haruddin
    Orient Neuron Nexus, 2010;1(1):13-16.
    MyJurnal
    Traumatic brain injury (TBI) is known to inflict significant morbidity and mortality worldwide. In severe TBI cases, the resulting physical and cognitive impairments incur high management and rehabilitation costs that crucially involve monitoring intracranial pressure (ICP) and improving brain oxygenation. Normobaric Hyperoxia Treatment (NBOT) is a therapeutic strategy to improve brain oxygen metabolism and to decrease ICP by reducing tissue swelling and deactivating toxin. NBOT is administered by increasing the inspired oxygen concentration to 100% in normal atmospheric pressure. Previous studies involving NBOT had explored its effectiveness to salvage the TBI-related cognitive and motor deficits. However, the focus of these studies has frequently been on the cortical lesions despite the known facts that TBI often inflicts tissue damage to the subcortical areas such as the basal ganglia. There are growing evidence to support recent functional theories that implicate a pivotal role of the basal ganglia in regulating normal movements and cognition through dopamine (DA) and glutamate interaction. Thus, tissue damages leading to TBI-related motor and cognitive deficits may involve the different affected brain regions. This minireview attempts to highlight the key processes involved in the pathophysiology of severe TBI and offers insights into the role of NBOT by exploring its potential effects on the cerebral energy metabolism and gene expression patterns of dopamine receptor in a mouse model.
    Matched MeSH terms: Oxygen
  13. Azrina, M.R., Saedah Ali, Mohd Nikman Ahmad, Nik Abdullah, N.M., Ziyadi Mohd Ghazali
    MyJurnal
    Introduction and Objectives: The intensive care unit (ICU) is an uncomfortable and stressful environment for patients. The use of adequate sedation and analgesia is important to reduce stress to patients. The aim of this study was to compare a relatively new sedative agent, dexmedetomidine to current sedative agent used, propofol in the provision of sedation and analgesia, their effects on haemodynamic and respiratory parameters and cost involved on post open heart surgery patients. Materials and Methods: A prospective, randomized single-blinded trial was conducted on post open heart surgery patients in the ICU of the Hospital Universiti Sains Malaysia (HUSM). Thirty two patients were randomized to dexmedetomidine or propofol groups. Analgesic requirement, haemodynamic and respiratory parameters, and extubation time were measured and compared. Mean rate of infusion to achieve adequate sedation were used to calculate the cost involved in the use of these two agents. Results: Patients sedated with dexmedetomidine required significantly lower dose of morphine compared to propofol [mean (sd): 12.80 (2.61) versus 15.86 (1.87) mg/kg/min, p=0.00]. Mean heart rate was also significantly lower in dexmedetomidine group compared to propofol group [mean (CI): 74.48 (70.38,78.59) versus 83.85 (79.61,88.09) per minutes, p=0.00]. However there were no significant differences in the other parameters between the two groups. Cost involved the use of dexmedetomidine was slightly higher compared to propofol (RM 9.57 versus RM8.94 per hour). Discussion and Conclusions: Dexmedetomidine is comparable to propofol in the provision of sedation, and its effect on haemodynamic and respiratory parameters. However it has added advantages in the provision of analgesia, and caused a significant reduction in heart rate. This is beneficial in these patients by reducing myocardial oxygen demand, and hence subsequent ischaemia and infarction. However, further larger studies are needed to evaluate the effect of dexmedetomidine on perioperative cardiac morbidity and mortality.
    Matched MeSH terms: Oxygen
  14. Ismail, A. F., Sapari, N., Abdul Wahab, M. M.
    MyJurnal
    Land development, especially construction works, increase storm water volumes and pollution loads into rivers and lakes. The temporary drainage system at construction sites, particularly during the construction stage discharges a large amount of pollutants that can damage the aquatic system of the receiving water bodies. The potential of vegetative swale to alleviate this problem was evaluated. The size of the constructed vegetative swale was 7cm deep, 400cm long and 15cm wide at the bottom, and 17cm wide at the top. The experiment was conducted batch wise by filling the storage tank with the run-off water from the construction site. The water was allowed to flow through a pipe into the retention basin to maintain uniform flow before it entered the swale. The study showed that the run-off infiltrated through the soil at a rate of 489.6 mm/hr. Samples of surface run-off and infiltration water were collected at the end and the bottom of the swale. The results indicate that chemical oxygen demand (COD), total suspended solid (TSS), turbidity, iron and zinc were reduced by 85.4%, 80.8%, 36.4%, 52.8% and 96.0%, respectively, by surface flow and 91.1%, 98.8%, 58.2% 55.5% and 98.1%, respectively, by infiltration. Removal of nitrate and phosphorus by the planted vegetation was 69.4% and 21.1%, respectively, by infiltration. However, nutrient removal by surface flow was negligible. In conclusion, the vegetative swale was able to improve the water quality of the storm water run-off from the construction site from Class V to Class III, according to the Interim National Water Quality Standards for Malaysia.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  15. Wan Rahiza, W.M., Nurlia, Y., Abd Rahman, I., Esa, K., Nadia, M.N., Raha, A. R.
    MyJurnal
    Supraglottic airway devices have been used as safe alternatives to endotracheal intubation in appropriate types of surgery. This was a prospective, randomised, single blind study comparing the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and occurrence of adverse effects (e.g. blood stains on the device upon removal and sore throat). A total of 62 ASA I or II patients, aged between 18 to 70 years were recruited for this study. Patients were randomised into two groups; LMA™ and SLIPA™ group. Following induction of anaesthesia, an appropriate sized LMA™ or SLIPA™ was inserted after ensuring adequate depth of anaesthesia. Anaesthesia was maintained with oxygen, nitrous oxide and sevoflurane. The ease of insertion was graded and haemodynamic changes were recorded at 2 minute intervals up to 10 minutes after insertion of the airway devices. The presence of blood stains upon airway device removal at the end of surgery and incidence of sore throat was also recorded. No difficult insertion was experienced in either of these devices. Insertion was either easy [LMA™ 87.1% versus SLIPA™ 80.6% (p = 0.49)] or moderate [LMA™ 12.9% versus SLIPA™ 19.4% (p = 0.16)]. Throughout the study period, the haemodynamic changes that occurred in both groups were not statistically different. Traces of blood were noted on the surface of the device in 9.7% of patients in the SLIPA™ group versus 6.5% of patients in the LMA™ group. The incidence of sore throat was recorded in 12.9% versus 19.4% of patients in the SLIPA™ and the LMA™ groups respectively. These findings were not statistically significant. In conclusion, this study showed no significant differences between the use of LMA™ and SLIPA™ in terms of ease of insertion, haemodynamic changes and adverse effects in patients undergoing minor surgical procedures.
    Matched MeSH terms: Oxygen
  16. Kostadinović Veličkovska S, Catalin Moţ A, Mitrev S, Gulaboski R, Brühl L, Mirhosseini H, et al.
    J Food Sci Technol, 2018 May;55(5):1614-1623.
    PMID: 29666513 DOI: 10.1007/s13197-018-3050-0
    The bioactive compounds and "in vitro" antioxidant activity measured by three antioxidant assays of some traditional and non-traditional cold-pressed edible oils from Macedonia were object of this study. The fatty acid composition showed dominance of monounsaturated oleic acid in "sweet" and "bitter" apricot kernel oils with percentages of 66.7 ± 0.5 and 57.8 ± 0.3%, respectively. The most dominant fatty acid in paprika seed oil was polyunsaturated linoleic acid with abundance of 69.6 ± 2.3%. The most abundant tocopherol was γ-tocopherol with the highest quantity in sesame seed oil (57.6 ± 0.1 mg/100 g oil). Paprika seed oil, sesame seed oil and sweet apricot oil were the richest source of phytosterols. DPPH assay was the most appropriate for the determination of the antioxidant activity of cold-pressed sunflower oil due to high abundance of α-tocopherol with a level of 22.8 ± 1.1 mg/100 g of oil. TEAC assay is the best for the determination of the antioxidant activity of sesame seed oil and paprika seed oils as the richest sources of phenolic compounds. β-carotene assay was the most suitable assay for oils obtained from high pigmented plant material. Triacylglycerols and phytosterol profiles can be used as useful markers for the origin, variety and purity of the oils.
    Matched MeSH terms: Oxygen Radical Absorbance Capacity
  17. B. Hemabarathy Bharatham, Zariyantey Abdul Hamid, Nurnadiah Ahmad
    MyJurnal
    Biocompatibility and growth of osteoblast on bone scaffolds play an important role towards their therapeutic application.
    The presence of oxidative stress generated by bone scaffolds highly influences osteoblast growth and its functional
    performance. In this study in-vitro interaction of developed Alginate/Cockle Shell powder nanobiocomposite bone scaffold
    on osteoblast with regards to cytotoxicity and oxidative stress are evaluated. Cytotoxicity studies using MTT assays
    revealed a significant increase in viability of cultured osteoblast in the presences of the scaffold extracts. The growth of
    osteoblast on the scaffold were not deterred with the presence of any major oxidative stress factors as determined through
    oxidative stress profile studies using SOD, GSH and ROS assays. The nanobiocomposite scaffold evaluated in this study
    shows promising use in regards to facilitating osteoblast proliferation, growth and viability.
    Matched MeSH terms: Reactive Oxygen Species
  18. Abbasiliasi S, Tan JS, Ibrahim TAT, Ramanan RN, Kadkhodaei S, Mustafa S, et al.
    J Food Sci Technol, 2018 Apr;55(4):1270-1284.
    PMID: 29606741 DOI: 10.1007/s13197-018-3037-x
    This paper deliberates the modelling and validation of bacteriocin-like inhibitory substance (BLIS) secretion by Pediococcus acidilactici Kp10 at different agitation speeds in a stirred tank bioreactor. A range of models namely the re-parameterised logistic, Luedeking-Piret and maintenance energy were assessed to predict the culture performance of the said bacterium. Growth of P. acidilactici Kp10 was enhanced with increased agitation speed up to 600 rpm while BLIS secretion was maximum at 400 rpm but decreased at higher agitation speed. Growth of P. acidilactici aptly subscribed to the re-parameterised logistic model while BLIS secretion and lactose consumption fitted well with the Luedeking-Piret model. The models revealed a relationship between growth of the bacterium and BLIS secretion. Bacterial growth and BLIS secretion were largely affected by the agitation speed of the stirred tank bioreactor which regulated the oxygen transfer to the culture. BLIS secretion by P. acidilactici Kp10 was however enhanced in oxygen-limited culture. The study also assessed BLIS from the perspective of its stability when subjected to factors such as temperature, pH and detergents. Results showed that BLIS produced by this strain was not affected by heat (at 25-100 °C for 20 min and at 121 °C for 15 min), surfactant (Tween 40, 60 and 80 and urea), detergents (up to 1% SDS), organic solvents (50% each of acetone, methanol and ethanol) and stable in a wide range of pH (2-10). The above information are pertinent with reference to commercial applications of this bacterial product in food manufacturing which invariably involve various sterilization processes and subjected to a wide pH range.
    Matched MeSH terms: Oxygen
  19. Thung WE, Ong SA, Ho LN, Wong YS, Ridwan F, Oon YL, et al.
    J Environ Sci (China), 2018 Apr;66:295-300.
    PMID: 29628097 DOI: 10.1016/j.jes.2017.05.010
    This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell (UFML-MFC) in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand (COD) reduction and power generation, including the increase of KCl concentration (MFC1) and COD concentration (MFC2). The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC. Despite the COD reduction was up to 96%, the power output remained constrained.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  20. Hani Hafeeza Halim, Mohd Sabri Pak Dek, Azizah Abdul Hamid, Ahmad Haniff Jaafar
    MyJurnal
    Among athletes, endurance is one of the key elements to victory. In addition to
    training, athletes normally used supplement to prevent fatigue during the event. With
    prolonged and intense activity, our body started to experience decrease in muscle
    performance due to several factors such as oxidative stress, dehydration and
    accumulation of lactic acid in the body fluids. The free radicals generated during
    intense exercise will expose the cells to oxidative damages. In the event of
    dehydration, there will be significant losses of water and functional electrolytes during
    intense exercise which affected the body fluid balance. Fatigue will also occur during
    reduced oxygen in aerobic metabolism which later caused accumulation of lactic acid
    in the muscle. This will change the pH balance toward more acidic and caused the
    muscles to lose contractile efficiency. In addition, fatigue can also be studied using rats
    as model organism. Results from this activity can be useful to analyse cellular
    metabolism and physiology effects of the tested rats toward physical exercise.
    Therefore, this review aims to discuss the causes of fatigue through oxidative stress,
    dehydration and lactic acid accumulation. In addition, the effectiveness of using rats as
    a model system in measuring fatigue is also included in illustrating examples on fatigue
    assessment in vivo.
    Matched MeSH terms: Oxygen
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