Displaying publications 321 - 340 of 1086 in total

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  1. Chong KW, Hong FJ, Thomas NF, Low YY, Kam TS
    J Org Chem, 2017 06 16;82(12):6172-6191.
    PMID: 28552001 DOI: 10.1021/acs.joc.7b00753
    A systematic study was undertaken to determine the influence of ortho'-substituted nucleophilic groups (OH, NH2, or NHR) on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals. The results showed that when ortho-substituted nucleophilic groups such as OH and NHR are present in the other ring, both direct and crossover intramolecular cation-nucleophile reactions occur to give bisbenzofurans/bisindoles or fused bisbenzopyrans/bisquinolines, respectively. Where an additional 3-methoxy substituent is present, bridged oxocine/azocine products are formed in addition to the bisbenzopyrans/bisquinolines and bisbenzofurans/bisindoles. Mechanistic rationalization of the observed behavior is presented based on a generalized pathway involving fast cation radical dimerization following electron transfer, followed by direct and crossover trapping of the benzylic cations by the ortho-substituted oxygen and nitrogen nucleophilic groups. In the instances where an additional 3-methoxy group is present, the bridged oxocine/azocine products are also formed as a result of competing aromatic substitution (Friedel-Crafts reaction). The results have shed further light and provided additional clarification on the reactivity of anodically generated stilbene cation radicals.
    Matched MeSH terms: Oxygen
  2. Yap CJ, Lam SM, Sin JC, Zeng H, Li H, Huang L, et al.
    Environ Sci Pollut Res Int, 2023 Sep;30(42):96272-96289.
    PMID: 37566326 DOI: 10.1007/s11356-023-29165-6
    Attributable to the prosperous production growth of palm oil in Malaysia, the generated palm oil mill effluent (POME) poses a high threat owing to its highly polluted characteristic. Urged by the escalating concern of environmental conservation, POME pollution abatement and potential energy recovery from the effluent are flagged up as a research topic of interest. In this study, a cutting-edge photocatalytic fuel cell (PFC) system with employment of ZnO/Zn nanorod array (NRA) photoanode, CuO/Cu cathode, and persulfate (PS) oxidant was successfully designed to improve the treatment of POME and simultaneous energy production. The photoelectrodes were fabricated and characterized by field emission scanning electron microscopy with energy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and Brunauer, Emmett, and Teller analysis (BET). Owing to the properties of strong oxidant of PS, the proposed PFC/PS system has exhibited exceptional performance, attaining chemical oxygen demand (COD) removal efficiency of 96.2%, open circuit voltage (Voc) of 740.0 mV, short circuit current density (Jsc) of 146.7 μA cm-2, and power density (Pmax) of 35.6 μW cm-2. The pre-eminent PFC/PS system performance was yielded under optimal conditions of 2.5 mM of persulfate oxidant, POME dilution factor of 1:20, and natural solution pH of 8.51. Subsequently, the postulated photoelectrocatalytic POME treatment mechanism was elucidated by the radical scavenging study and Mott-Schottky (M-S) analysis. The following recycling test affirmed the stability and durability of the photoanode after four continuous repetition usages while the assessed electrical energy efficiency revealed the economic viability of PFC system serving as a post-treatment for abatement of POME. These findings contributed toward enhancing the sustainability criteria and economic viability of palm oil by adopting sustainable and efficient POME post-treatment technology.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  3. Ibrahim A, Mat Ludin AF, Shahar S, Hamzah NH, Chin AV, Singh DKA
    Exp Gerontol, 2023 Dec;184:112326.
    PMID: 37967590 DOI: 10.1016/j.exger.2023.112326
    INTRODUCTION: Cardiorespiratory fitness has an inverse relationship with cognitive impairment and frailty in older adults. Direct assessment of maximal oxygen consumption (VO2 max) is the gold standard to assess cardiorespiratory fitness. However, it is costly and requires a laboratory setting. Therefore, VO2 max estimation among older adults with cognitive frailty (CF) will allow the assessment of aerobic capacity, which is commonly overlooked due to the complexity of the test.

    AIM: This study aims to determine the use of one of three physical performance tests (2-minute step, 2-minute walk, and 1-minute sit to stand) to effectively estimate cardiorespiratory fitness among older adults with CF.

    METHODS: In this cross-sectional study, community-dwelling individuals aged 60 years old and above in Klang Valley were screened for CF. The participants performed three physical performance tests (2-minute walk, 2-minute step, and 1-minute sit to stand) followed by treadmill-based maximal exercise testing on another day.

    RESULTS: A total of 32 older adults with cognitive frailty (mean age; SD: 67.1;4.7 years) participated in this study. Nearly half of them had hypertension (43.5 %), hypercholesterolemia (43.5 %), and multimorbidity (47.8 %). Among the endurance tests performed, only the 2-minute walk test independently predicted VO2 max by sex-specific with men (R2 = 0.58, p = 0.03) and women (R2 = 0.34, p = 0.01). The 2-minute walk test had good agreement with VO2 max (ICC = 0.77, 95 % CI: -3.1-2.4).

    CONCLUSION: The 2-minute walk test is a valid tool for estimating cardiorespiratory fitness among older adults with CF. However, it should be further tested across a larger population.

    Matched MeSH terms: Oxygen Consumption
  4. Wan Hassan WM, Najid NM, Muslim HS, Izaini Ghani AR
    Asian J Neurosurg, 2015 3 15;10(1):59.
    PMID: 25767595 DOI: 10.4103/1793-5482.151528
    Barbiturate coma therapy (BCT) is a choice treatment for refractory intracranial hypertension after all surgical or medical managements have failed to control the intracranial pressure (ICP). It helps to reduce cerebral blood flow, cerebral metabolic rate of oxygen consumption and ICP. However, this therapy can also cause many complications. One of the underreported, but life-threatening complications is refractory hypokalemia, which can lead to subsequent rebound hyperkalemia after sudden cessation. We report our experience of managing unusual complication of refractory hypokalemia during BCT with thiopentone in postdecompressive craniectomy patient.
    Matched MeSH terms: Oxygen Consumption
  5. Sokran SN, Mohan V, Kamaruddin K, Sulaiman MD, Awang Y, Othman IR, et al.
    Iran J Med Sci, 2015 Jul;40(4):335-40.
    PMID: 26170520
    Hand grip strength (HGS) is a reliable indicator of peripheral muscle strength. Although, numerous studies have investigated the strength of hand grip; little attention has been given to coronary artery disease (CAD) patients, exploring the relationship between HGS and myocardial oxygen consumption (MVO2) index. The current study aimed to evaluate the interaction between HGS and MVO2 index findings before and after cardiac surgery.
    Matched MeSH terms: Oxygen Consumption
  6. Nguyen D, Yaacob Y, Muda S, Mohamed Z
    Malays J Med Sci, 2013 Mar;20(2):70-5.
    PMID: 23983581 MyJurnal
    Pulmonary thromboembolism is a life-threatening cardiovascular condition. The mortality rate is high in its current management. Besides supportive treatments, systemic thrombolysis and surgical thrombectomy play important roles in the comprehensive management of pulmonary embolism (PE). The percutaneous catheter-based rheolytic thrombectomy is a promising alternative for management of massive pulmonary emboli, particularly, when patients have contraindication with systemic thrombolysis or are not suitable for surgery. We present the case of a 36-year-old Somalian man who came to our center for a total knee replacement (TKR). Three days after TKR, he developed sudden shortness of breath and decreased oxygen saturation. Computed tomography of pulmonary arteriogram showed extensive thrombi within the main pulmonary trunk, right and left pulmonary arteries, bilateral ascending and bilateral descending pulmonary arteries in keeping with massive PE. Because the patient was contraindicated for systemic thrombolysis, percutaneous, catheter-based rheolytic thrombectomy was chosen as the alternative treatment. His clinical symptoms improved immediately post-treatment. In conclusion, catheter-based rheolytic thrombectomy can serve as an alternative treatment for massive PE with a good clinical outcome.
    Matched MeSH terms: Oxygen
  7. Chin HJ, Seng QB
    Malays J Med Sci, 2004 Jul;11(2):34-40.
    PMID: 22973125 MyJurnal
    Children with bronchiolitis from Hospitals Universiti Sains Malaysia (HUSM) and Hospital Kota Bharu (HKB) were student using the Kristjansson Respiratory Score and the Wang Respiratory Score respectively. Saturation of oxygen (S(a)O(2)) was measured with a pulse-oximeter while the child is breathing room-air. Two observers assessed the respiratory scores in all children independently. The correlation between respiratory scores and S(a)O(2) was assessed using Spearman's Rho, and the inter-rater reliability of respiratory scores determined using intraclasscorelation coefficient. There were 29 children in HUSM and 25 from HKB with a median age of 8 months (IQR 4.5 months) and 9 months(IQR 7 months) respectively. In HUSM, the median Kristjansson Respiratory Score for both observers was 4 (IQR 2), and the median S(a)O(2) was 96% (IQR 3%). The correlation coefficient between the Kristjansson Respiratory Score and S(a)O(2) for the first observer was - 0.75 (p <0.001), and for the second observer -0.73 (p <0.001). In HKB, the median Wang Respiratory Score was also similar for both observers (median 4 IQR 4.5), and the median (IQR) for S(a)O(2) was 96% (2%). The correlation coefficient between the Wang Respiratory Score and S(a)O(2) for the first observer was -0.41 (p = 0.04) and for the second observer -0.43 (p = 0.03). The inter-rater reliability between the first and second observer was high for both the Kristjansson Respiratory (ICC 0.89) and the Wang Respiratory Scores (ICC 0.99). In conclusion the validity of the Kristjansson Respiratory Score was high whereas the validity of the Wang Respiratory Score was moderate in the assessment of the severity of acute bronchiolitis. Both respiratory scores and physical signs showed high agreement between observers. The Kristjansson Respiratory Score should be considered for use by medical personnel in the assessment of the severity of acute bronchiolitis in children.
    Matched MeSH terms: Oxygen
  8. Qutob M, Alshehri S, Shakeel F, Alam P, Rafatullah M
    Environ Sci Pollut Res Int, 2024 Apr;31(18):26452-26479.
    PMID: 38546921 DOI: 10.1007/s11356-024-33040-3
    The advanced oxidation process (AOP) is an efficient method to treat recalcitrance pollutants such as pharmaceutical compounds. The essential physicochemical factors in AOP experiments significantly influence the efficiency, speed, cost, and safety of byproducts of the treatment process. In this review, we collected recent articles that investigated the elimination of pharmaceutical compounds by various AOP systems in a water medium, and then we provide an overview of AOP systems, the formation mechanisms of active radicals or reactive oxygen species (ROS), and their detection methods. Then, we discussed the role of the main physicochemical parameters (pH, chemical interference, temperature, catalyst, pollutant concentration, and oxidant concentration) in a critical way. We gained insight into the most frequent scenarios for the proper and improper physicochemical parameters for the degradation of pharmaceutical compounds. Also, we mentioned the main factors that restrict the application of AOP systems in a commercial way. We demonstrated that a proper adjustment of AOP experimental parameters resulted in promoting the treatment performance, decreasing the treatment cost and the treatment operation time, increasing the safeness of the system products, and improving the reaction stoichiometric efficiency. The outcomes of this review will be beneficial for future AOP applicants to improve the pharmaceutical compound treatment by providing a deeper understanding of the role of the parameters. In addition, the proper application of physicochemical parameters in AOP systems acts to track the sustainable development goals (SDGs).
    Matched MeSH terms: Reactive Oxygen Species
  9. Harbi AS, Soh KL, Yubbu PB, Soh KG
    F1000Res, 2024;13:596.
    PMID: 38984016 DOI: 10.12688/f1000research.152315.1
    BACKGROUND: Cardiovascular disease (CVD) continues to be the foremost mortality internationally. Cardiac rehabilitation has proven as an effective program in reducing CVD burden. Participation in cardiac rehabilitation programs is very low. Digital health intervention emerged as an alternative method to deliver Cardiac rehabilitation. This review aimed to investigate the impact of digital health intervention on the outcomes of interest.

    METHODS: the following databases: PubMed, CINAHL, Scopus, and Cochrane Library have been searched to retrieve randomized controlled trials that examine the impact of digital health intervention on blood pressure, body mass index, lipid profile, blood glucose, Six-Minute Walk Test, and peak oxygen consumption. filters were set to include studies published in English between 2000-2023.

    RESULTS: Nineteen studies were included in this review. Six-Minute Walk Test (MD = 16.70; 95% CI: 6.00 to 27.39, p = 0.000) and maximal oxygen consumption (SMD = 0.27; 95% CI: 0.08 to 0.45, p = 0.004) significantly improved following digital health intervention, after employing the sensitivity analysis significant improvement was observed in systolic (MD = -2.54; 95% CI: -4.98 to -0.11, p = 0.04) and diastolic blood pressure (SMD = -2.0182; 95% CI: -3.9436 to -0.0928, p = 0.04) favoring experimental groups. Subgroup analysis revealed significant improvement in quality of life after three months of follow-up (SMD = 0.18; 95% CI: 0.05 to 0.31, p = 0.00), no significant differences have been observed in body mass index, lipid profile, and blood glucose.

    CONCLUSION: The findings emphasize the significant impact of digital vs CBCR or usual care on physical capacity, blood pressure, and quality of life. Despite the non-statistically significant differences in body mass index and lipid profile, the comparable effect between the two methods suggests the superiority of digital over CBCR or usual care due to its convenient nature, accessibility, and cost-effectiveness.

    Matched MeSH terms: Oxygen Consumption
  10. Shaharudin S, Agrawal S
    J Sports Med Phys Fitness, 2016 Sep;56(9):980-9.
    PMID: 25732319
    BACKGROUND: The purpose of this study was to evaluate the muscle synergies during incremental rowing VO2 max Test of collegiate rowers and untrained subjects. As a power endurance sport, high aerobic capacity was one of the determinants of rowing performance. The modulation of muscle recruitment patterns following specific physiological demands was an indication of the robustness of muscle synergies composition which was overlooked in previous studies.

    METHODS: Ten male collegiate rowers and physically active untrained subjects were recruited. Muscle synergies were extracted from 16 rowing-specific muscles using Principal Component Analysis with varimax rotation. Incremental rowing VO2 max Test was performed on slides ergometer (SE). Rowing performance and physiological variables were analyzed.

    RESULTS: Rowers exerted greater power output, more energy expenditure and better rowing economy compared to untrained subjects. Rowers preferred to row slower with longer strokes compared to the untrained subjects. Three muscle synergies with high indices of similarity of waveform patterns were extracted in both groups. Significant association was found between muscle synergies and rowing economy.

    CONCLUSIONS: The findings of this study showed that muscle synergies were robust during aerobic-dominant activity for collegiate rowers and untrained subjects. Rowers and coaches could utilize the findings by emphasizing on muscle coordination training, which may enhance the rowing economy.

    Matched MeSH terms: Oxygen Consumption/physiology*
  11. Kamba AS, Ismail M, Ibrahim TA, Zakaria ZA
    PMID: 25392577
    BACKGROUND: Currently, there has been extensive research interest for inorganic nanocrystals such as calcium phosphate, iron oxide, silicone, carbon nanotube and layered double hydroxide as a drug delivery system especially in cancer therapy. However, toxicological screening of such particles is paramount importance before use as delivery carrier. In this study we examine the biocompatibility of CaCO3 nanocrystal on NIH 3T3 cell line.

    MATERIAL AND METHODS: Transmission and field emission scanning electron microscopy (TEM and FESEM) were used for the characterisation of CaCO3 nanocrystals. Cytotoxicity and genotoxic effect of calcium carbonate nanocrystals in cultured mouse embryonic fibroblast NIH 3T3 cell line using various bioassays including MTT, and Neutral red/Trypan blue double-staining assays. LDH, BrdU and reactive oxygen species were used for toxicity analysis. Cellular morphology was examined by scanning electron microscopy (SEM) and confocal fluorescence microscope.

    RESULTS: The outcome of the analyses revealed a clear rod-shaped aragonite polymorph of calcium carbonate nanocrystal. The analysed cytotoxic and genotoxicity of CaCO3 nanocrystal on NIH 3T3 cells using different bioassays revealed no significance differences as compared to control. A slight decrease in cell viability was noticed when the cells were exposed to higher concentrations of 200 to 400 µg/ml, while increase in ROS generation and LDH released at 200 and 400 µg/ml was observed.

    CONCLUSIONS: The study has shown that CaCO3 nanocrystal is biocompatible and non toxic to NIH 3T3 fibroblast cells. The analysed results offer a promising potential of CaCO3 nanocrystal for the development of intracellular drugs, genes and other macromolecule delivery systems.

    Matched MeSH terms: Reactive Oxygen Species/metabolism
  12. Liew KH, Loh PL, Juan JC, Yarmo MA, Yusop RM
    ScientificWorldJournal, 2014;2014:796196.
    PMID: 25054185 DOI: 10.1155/2014/796196
    Cross-linked resin-captured palladium (XL-QPPd) was readily prepared by simple physical adsorption onto the high loading QuadraPure macroporous resin and a subsequent reduction process. To enhance the mechanical stability, entrapped palladium nanocatalysts were cross-linked with succinyl chloride. Both transmission electron microscopy images and X-ray diffraction analysis revealed that the palladium nanoparticles were well dispersed with diameters ranging in 4-10 nm. The catalyst performed good catalytic activity in microwave-promoted Suzuki cross-coupling reactions in water under aerobic condition with mild condition by using various aryl halides and phenylboronic acid. In addition, the catalyst showed an excellent recyclability without significant loss of catalytic activity.
    Matched MeSH terms: Oxygen/chemistry
  13. Zhou X, Qu Y, Kim BH, Choo PY, Liu J, Du Y, et al.
    Bioresour Technol, 2014 Oct;169:265-70.
    PMID: 25062537 DOI: 10.1016/j.biortech.2014.07.012
    The effects of azide on electron transport of exoelectrogens were investigated using air-cathode MFCs. These MFCs enriched with azide at the concentration higher than 0.5mM generated lower current and coulomb efficiency (CE) than the control reactors, but at the concentration lower than 0.2mM MFCs generated higher current and CE. Power density curves showed overshoot at higher azide concentrations, with power and current density decreasing simultaneously. Electrochemical impedance spectroscopy (EIS) showed that azide at high concentration increased the charge transfer resistance. These analyses might reflect that a part of electrons were consumed by the anode microbial population rather than transferred to the anode. Bacterial population analyses showed azide-enriched anodes were dominated by Deltaproteobacteria compared with the controls. Based on these results it is hypothesized that azide can eliminate the growth of aerobic respiratory bacteria, and at the same time is used as an electron acceptor/sink.
    Matched MeSH terms: Oxygen/analysis
  14. Muthuraju S, Islam MR, Pati S, Jaafar H, Abdullah JM, Yusoff KM
    Int J Neurosci, 2015;125(9):686-92.
    PMID: 25180987 DOI: 10.3109/00207454.2014.961065
    Dopamine (DA) is one of the key neurotransmitters in the striatum, which is functionally important for a variety of cognitive and motor behaviours. It is known that the striatum is vulnerable to damage from traumatic brain injury (TBI). However, a therapeutic approach has not yet been established to treat TBI. Hence, the present work aimed to evaluate the ability of Normobaric hyperoxia treatment (NBOT) to recover dopaminergic neurons following a fluid percussion injury (FPI) as a TBI experimental animal model. To examine this, mice were divided into four groups: (i) Control, (ii) Sham, (iii) FPI and (iv) FPI+NBOT. Mice were anesthetized and surgically prepared for FPI in the striatum and immediate exposure to NBOT at various time points (3, 6, 12 and 24 h). Dopamine levels were then estimated post injury by utilizing a commercially available ELISA method specific to DA. We found that DA levels were significantly reduced at 3 h, but there was no reduction at 6, 12 and 24 h in FPI groups when compared to the control and sham groups. Subjects receiving NBOT showed consistent increased DA levels at each time point when compared with Sham and FPI groups. These results suggest that FPI may alter DA levels at the early post-TBI stages but not in later stages. While DA levels increased in 6, 12 and 24 h in the FPI groups, NBOT could be used to accelerate the prevention of early dopaminergic neuronal damage following FPI injury and improve DA levels consistently.
    Matched MeSH terms: Oxygen Inhalation Therapy/methods*
  15. Khor SC, Abdul Karim N, Ngah WZ, Yusof YA, Makpol S
    Oxid Med Cell Longev, 2014;2014:914853.
    PMID: 25097722 DOI: 10.1155/2014/914853
    Sarcopenia is a geriatric syndrome that is characterized by gradual loss of muscle mass and strength with increasing age. Although the underlying mechanism is still unknown, the contribution of increased oxidative stress in advanced age has been recognized as one of the risk factors of sarcopenia. Thus, eliminating reactive oxygen species (ROS) can be a strategy to combat sarcopenia. In this review, we discuss the potential role of vitamin E in the prevention and treatment of sarcopenia. Vitamin E is a lipid soluble vitamin, with potent antioxidant properties and current evidence suggesting a role in the modulation of signaling pathways. Previous studies have shown its possible beneficial effects on aging and age-related diseases. Although there are evidences suggesting an association between vitamin E and muscle health, they are still inconclusive compared to other more extensively studied chronic diseases such as neurodegenerative diseases and cardiovascular diseases. Therefore, we reviewed the role of vitamin E and its potential protective mechanisms on muscle health based on previous and current in vitro and in vivo studies.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  16. Chin Y, Lim SH, Zorlu Y, Ahsen V, Kiew LV, Chung LY, et al.
    PLoS One, 2014;9(5):e97894.
    PMID: 24840576 DOI: 10.1371/journal.pone.0097894
    Phthalocyanines are excellent photosensitizers for photodynamic therapy as they have strong absorbance in the near infra-red region which is most relevant for in vivo activation in deeper tissular regions. However, most phthalocyanines present two major challenges, ie, a strong tendency to aggregate and low water-solubility, limiting their effective usage clinically. In the present study, we evaluated the potential enhancement capability of glycerol substitution on the photodynamic properties of zinc (II) phthalocyanines (ZnPc). Three glycerol substituted ZnPc, 1-3, (tetra peripherally, tetra non-peripherally and mono iodinated tri non-peripherally respectively) were evaluated in terms of their spectroscopic properties, rate of singlet oxygen generation, partition coefficient (log P), intracellular uptake, photo-induced cytotoxicity and vascular occlusion efficiency. Tetrasulfonated ZnPc (ZnPcS4) was included as a reference compound. Here, we showed that 1-3 exhibited 10-100 nm red-shifted absorption peaks with higher molar absorptivity, and at least two-fold greater singlet oxygen generation rates compared to ZnPcS4. Meanwhile, phthalocyanines 1 and 2 showed more hydrophilic log P values than 3 consistent with the number of glycerol attachments but 3 was most readily taken up by cells compared to the rest. Both phthalocyanines 2 and 3 exhibited potent phototoxicity against MCF-7, HCT-116 and HSC-2 cancer cell-lines with IC50 ranging 2.8-3.2 µM and 0.04-0.06 µM respectively, while 1 and ZnPcS4 (up to 100 µM) failed to yield determinable IC50 values. In terms of vascular occlusion efficiency, phthalocyanine 3 showed better effects than 2 by causing total occlusion of vessels with diameter <70 µm of the chorioallantoic membrane. Meanwhile, no detectable vascular occlusion was observed for ZnPcS4 with treatment under similar experimental conditions. These findings provide evidence that glycerol substitution, in particular in structures 2 and 3, is able to improve the photodynamic properties of ZnPc.
    Matched MeSH terms: Singlet Oxygen/metabolism
  17. Jothy SL, Oon CE, Sasidharan S
    Asian Pac J Cancer Prev, 2014;15(3):1501.
    PMID: 24606490
    Matched MeSH terms: Reactive Oxygen Species/therapeutic use*
  18. Lee WL, Huang JY, Shyur LF
    Oxid Med Cell Longev, 2013;2013:925804.
    PMID: 24454991 DOI: 10.1155/2013/925804
    Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The "double-edged sword" role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.
    Matched MeSH terms: Reactive Oxygen Species/metabolism*
  19. Mohd Sauid S, Krishnan J, Huey Ling T, Veluri MV
    Biomed Res Int, 2013;2013:409675.
    PMID: 24350269 DOI: 10.1155/2013/409675
    Volumetric mass transfer coefficient (kLa) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v) of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h(-1). It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.
    Matched MeSH terms: Oxygen/metabolism*
  20. Naharudin MN, Yusof A
    PLoS One, 2013;8(10):e77290.
    PMID: 24204790 DOI: 10.1371/journal.pone.0077290
    BACKGROUND: Since hypohydration commonly occurs in sports, studies on anaerobic exercise performance under this condition have been extensively carried out. When describing anaerobic performance, authors usually refer to a drop in anaerobic performance as fatigue index (FI) which is conventionally calculated using peak and low power data points. Meanwhile, another possible method in explaining anaerobic fatigue is using the rate constant which is derived from the exponential decline of power output known as fatigue rate (FR). Few studies have demonstrated that there was no change in anaerobic performance under mild hypohydrations.

    PURPOSE: This study aimed to compare the kinetics of power output using FI and FR of an anaerobic performance (Wingate test) under 2, 3 and 4% state of hypohydrations.

    METHOD: Thirty two collegiate cyclists (age = 22 ± 2 years; body weight = 71.45 ± 3.43 kg; height = 173.23 ± 0.04 cm) were matched using their baseline anaerobic peak power (APP) then randomly divided into 4 groups of EU (euhydrated), 2H, 3H and 4H respectively.

    RESULTS: As expected the, FI, APP, anaerobic lower power (ALP) and rating of perceived exertion (RPE) did not show significant differences between and within the groups. However, the FR in 3H (0.018 ± 0.005 s(-1)) and 4H (0.019 ± 0.010 s(-1)) were significantly lower than EU (0.033 ± 0.012 s(-1)). Post-test FR also showed significant reduction in 3H and 4H compared to their pre-test values (p<0.05).

    CONCLUSION: Despite the lack of changes in APP and RPE, subjects in 3H and 4H showed evidence of lower reduction of power output over time. The findings support earlier reports which showed no change in anaerobic performance under mild hypohydrations. The relatively lower FR suggests higher drive in maintaining power output under hypohydrations of 3 and 4% body weight.

    Matched MeSH terms: Oxygen Consumption/physiology
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