Displaying publications 401 - 420 of 1086 in total

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  1. An efficient oxic-anoxic process for treating low COD/N tropical wastewater: Startup, optimization and nitrifying community structure
    How SW, Nittami T, Ngoh GC, Curtis TP, Chua ASM
    Chemosphere, 2020 Nov;259:127444.
    PMID: 32640378 DOI: 10.1016/j.chemosphere.2020.127444
    In this study, we assessed and optimized a low-dissolved-oxygen oxic-anoxic (low-DO OA) process to achieve a low-cost and sustainable solution for wastewater treatment systems in the developing tropical countries treating low chemical oxygen demand-to-nitrogen ratio (COD/N) wastewater. The low-DO OA process attained complete ammonia removal and the effluent nitrate nitrogen (NO3-N) was below 0.3 mg/L. The recommended hydraulic retention time and sludge retention time (SRT) were 16 h and 20 days, respectively. The 16S rRNA sequencing data revealed that long SRT (20 days) encouraged the growth of nitrite-oxidizing bacteria (NOB) affiliated with "Candidatus Nitrospira defluvii". Comammox made up 10-20% of the Nitrospira community. NOB and comammox related to Nitrospira were enriched at long SRT (20 days) to achieve good low-DO nitrification performance. The low-DO OA process was efficient and has simpler design than conventional processes, which are keys for sustainable wastewater treatment systems in the developing countries treating low COD/N wastewater.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  2. Mitochondrial dysfunction as a central event for mechanisms underlying insulin resistance: the roles of long chain fatty acids
    Hafizi Abu Bakar M, Kian Kai C, Wan Hassan WN, Sarmidi MR, Yaakob H, Zaman Huri H
    Diabetes Metab Res Rev, 2015 Jul;31(5):453-75.
    PMID: 25139820 DOI: 10.1002/dmrr.2601
    Insulin resistance is characterized by hyperglycaemia, dyslipidaemia and oxidative stress prior to the development of type 2 diabetes mellitus. To date, a number of mechanisms have been proposed to link these syndromes together, but it remains unclear what the unifying condition that triggered these events in the progression of this metabolic disease. There have been a steady accumulation of data in numerous experimental studies showing the strong correlations between mitochondrial dysfunction, oxidative stress and insulin resistance. In addition, a growing number of studies suggest that the raised plasma free fatty acid level induced insulin resistance with the significant alteration of oxidative metabolism in various target tissues such as skeletal muscle, liver and adipose tissue. In this review, we herein propose the idea of long chain fatty acid-induced mitochondrial dysfunctions as one of the key events in the pathophysiological development of insulin resistance and type 2 diabetes. The accumulation of reactive oxygen species, lipotoxicity, inflammation-induced endoplasmic reticulum stress and alterations of mitochondrial gene subset expressions are the most detrimental that lead to the developments of aberrant intracellular insulin signalling activity in a number of peripheral tissues, thereby leading to insulin resistance and type 2 diabetes.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  3. 4-chloro-1,2-phenylenediamine induces apoptosis in Mardin-Darby canine kidney cells via activation of caspases
    Onn LC, Ching CS, Lian TY, Foon LV, Chew Hee N, Moi CS
    Environ Toxicol, 2014 Jun;29(6):655-64.
    PMID: 22778066 DOI: 10.1002/tox.21792
    4-Chloro-1,2-phenylenediamine (4-Cl-o-PD) is a halogenated aromatic diamine that was used as a precursor for manufacturing permanent hair dyes. Despite its well-documented mutagenic and carcinogenic effects in a number of in vitro and in vivo models, its cytotoxicity and mode of action have not received similar attention. Here, we investigated the effect of 4-Cl-o-PD on Mardin-Darby canine kidney cells. It induced apoptosis and the evidence suggests its initiation by reactive oxygen species (ROS). The results of various assays used show a dose-dependent (i) decrease in cell viability, (ii) increase in cells at sub-G1 phase and the G0/G1 phase arrested in cell cycle, (iii) increase in intracellular ROS accompanied by depletion of glutathione, and (iv) that apoptotic cell death probably involves activation of both intrinsic and extrinsic pathways.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  4. Degradation of 17α-ethinylestradiol by nano zero valent iron under different pH and dissolved oxygen levels
    Karim S, Bae S, Greenwood D, Hanna K, Singhal N
    Water Res, 2017 11 15;125:32-41.
    PMID: 28826034 DOI: 10.1016/j.watres.2017.08.029
    The catalytic properties of nanoparticles (e.g., nano zero valent iron, nZVI) have been used to effectively treat a wide range of environmental contaminants. Emerging contaminants such as endocrine disrupting chemicals (EDCs) are susceptible to degradation by nanoparticles. Despite extensive investigations, questions remain on the transformation mechanism on the nZVI surface under different environmental conditions (redox and pH). Furthermore, in terms of the large-scale requirement for nanomaterials in field applications, the effect of polymer-stabilization used by commercial vendors on the above processes is unclear. To address these factors, we investigated the degradation of a model EDC, the steroidal estrogen 17α-ethinylestradiol (EE2), by commercially sourced nZVI at pH 3, 5 and 7 under different oxygen conditions. Following the use of radical scavengers, an assessment of the EE2 transformation products shows that under nitrogen purging direct reduction of EE2 by nZVI occurred at all pHs. The radicals transforming EE2 in the absence of purging and upon air purging were similar for a given pH, but the dominant radical varied with pH. Upon air purging, EE2 was transformed by the same radical species as the non-purged system at the same respective pH, but the degradation rate was lower with more oxygen - most likely due to faster nZVI oxidation upon aeration, coupled with radical scavenging. The dominant radicals were OH at pH 3 and O2- at pH 5, and while neither radical was involved at pH 7, no conclusive inferences could be made on the actual radical involved at pH 7. Similar transformation products were observed without purging and upon air purging.
    Matched MeSH terms: Oxygen/chemistry
  5. Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate
    Martin TE, Ton R, Niklison A
    Ecol Lett, 2013 Jun;16(6):738-45.
    PMID: 23473270 DOI: 10.1111/ele.12103
    Intrinsic processes are assumed to underlie life history expression and trade-offs, but extrinsic inputs are theorised to shift trait expression and mask trade-offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass-specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade-off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade-offs across species.
    Matched MeSH terms: Oxygen/metabolism
  6. Vernodalin induces apoptosis through the activation of ROS/JNK pathway in human colon cancer cells
    Mohebali N, Pandurangan AK, Mustafa MR, Anandasadagopan SK, Alagumuthu T
    J Biochem Mol Toxicol, 2020 Dec;34(12):e22587.
    PMID: 32726518 DOI: 10.1002/jbt.22587
    Colorectal cancer is one of the most leading death-causing cancers in the world. Vernodalin, a cytotoxic sesquiterpene, has been reported to possess anticancer properties against human breast cancer cells. We aimed to examine the anticancer mechanism of vernodalin on human colon cancer cells. Vernodalin was used on human colon cancer cells, HT-29 and HCT116. The cytotoxicity of vernodalin on human colon cancer cells was determined through in vitro 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Small interfering RNA was used to analyze the cascade activation of mitogen-activated protein kinase (MAPK) pathway, c-Jun N-terminal kinase (JNK) in HT-29, and HCT116 cells against vernodalin treatment. The protein expressions of caspase 3, Bcl-2, and Bax were examined through Western blot analysis. Immunoblot analysis on the JNK, ERK, and p38 MAPK pathways showed increased activation due to vernodalin treatment. It was proven from the JNK and p38 inhibition test that both pathways are significantly activated by vernodalin to induce apoptosis. Our results, collectively, showed the apoptosis-induced anticancer mechanism of vernodalin on human colon cancer cells that was mediated through the activation of JNK pathway and apoptotic regulator proteins. These results suggest that vernodalin could be developed as a potent chemotherapeutic agent for human colorectal cancer treatment.
    Matched MeSH terms: Reactive Oxygen Species/metabolism*
  7. A comparative study of the aerobic fitness of 421 healthy adult males in Singapore
    Ong TC
    J Sports Sci, 1993 Feb;11(1):71-6.
    PMID: 8450589 DOI: 10.1080/02640419308729966
    The maximum oxygen consumption (VO2 max) of 421 healthy adult males from three ethnic groups (Chinese, Malay and Indian), aged 25-54 years, was assessed from direct analyses of their expired respiratory gases during all-out runs on a treadmill as a measure of aerobic fitness. The subjects were divided into three age groups: group 1, 25-34 years; group 2, 35-44 years; group 3, 45-54 years. Each group was further subdivided into non-exercisers (NE), non-regular exercisers (NRE) and regular exercisers (RE). Consistently within each age group, regular exercisers produced significantly higher VO2 max values compared to non-regular exercisers and non-exercisers. They also met the VO2 max requirements for heavy physical work and compared favourably with the standards of the National Physical Fitness Award of Singapore and Cooper's aerobic fitness classification standards based on North American males. Non-regular exercisers and non-exercisers only met the VO2 max requirements for moderate physical work and compared poorly in both of the aerobic fitness standards.
    Matched MeSH terms: Oxygen Consumption*
  8. Comments on Point:Counterpoint: Sympathetic activity does/does not influence cerebral blood flow. When noradrenergic restraint of cerebral blood flow makes homeostatic sense
    Prakash ES
    J Appl Physiol (1985), 2008 10;105(4):1373.
    PMID: 18938648 DOI: 10.1152/japplphysiol.zdg-8199.pcpcomm.2008
    Matched MeSH terms: Oxygen/blood
  9. Possible Anticancer Mechanisms of Some Costus speciosus Active Ingredients Concerning Drug Discovery
    El-Far AH, Badria FA, Shaheen HM
    Curr Drug Discov Technol, 2016;13(3):123-143.
    PMID: 27515456
    Costus speciosus is native to South East Asia, especially found in India, Srilanka, Indonesia and Malaysia. C. speciosus have numerous therapeutic potentials against a wide variety of complains. The therapeutic properties of C. speciosus are attributed to the presence of various ingredients such as alkaloids, flavonoids, glycosides, phenols, saponins, sterols and sesquiterpenes. This review presented the past, present, and the future status of C. speciosus active ingredients to propose a future use as a potential anticancer agent. All possible up-regulation of cellular apoptotic molecules as p53, p21, p27, caspases, reactive oxygen species (ROS) generation and others attribute to the anticancer activity of C. speciosus along the down-regulation of anti-apoptotic agents such as Akt, Bcl2, NFKB, STAT3, JAK, MMPs, actin, surviving and vimentin. Eventually, we recommend further investigation of different C. speciosus extracts, using some active ingredients and evaluate the anticancer effect of these chemicals against different cancers.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  10. Near-infrared activatable phthalocyanine-poly-L-glutamic acid conjugate: increased cellular uptake and light-dark toxicity ratio toward an effective photodynamic cancer therapy
    Kiew LV, Cheah HY, Voon SH, Gallon E, Movellan J, Ng KH, et al.
    Nanomedicine, 2017 05;13(4):1447-1458.
    PMID: 28214608 DOI: 10.1016/j.nano.2017.02.002
    In photodynamic therapy (PDT), the low absorptivity of photosensitizers in an aqueous environment reduces singlet oxygen generation efficiency and thereby decreases photosensitizing efficacy in biological conditions. To circumvent this problem, we designed a phthalocyanine-poly-L-glutamic acid conjugate (1-PG) made from a new phthalocyanine (Pc 1) monofunctionalized to allow adequate conjugation to PGA. The resulting 1-PG conjugate retained high absorptivity in the near-infrared (NIR) region at its λmax675nm in an aqueous environment. The 1-PG conjugate demonstrated good singlet oxygen generation efficiency, increased uptake by 4 T1 breast cancer cells via clathrin-mediated endocytosis, and enhanced photocytotoxic efficacy. The conjugate also displayed a high light-dark toxicity ratio, approximately 1.5-fold greater than zinc phthalocyanine at higher concentration (10 μM), an important feature for the reduction of dark toxicity and unwanted side effects. These results suggest that the 1-PG conjugate could be a useful alternative for deep tissue treatment with enhanced anti-cancer (PDT) efficacy.
    Matched MeSH terms: Singlet Oxygen/chemistry
  11. Oxygen therapy and pulmonary fibroplasia: a review and case reports
    Chew DT, Yin AL
    Med J Malaya, 1971 Dec;26(2):122-8.
    PMID: 4260858
    Matched MeSH terms: Oxygen Inhalation Therapy/adverse effects*
  12. Fulltext Bilateral tension pneumothorax after acupuncture
    Mohammad N
    BMJ Case Rep, 2018 Apr 19;2018.
    PMID: 29674395 DOI: 10.1136/bcr-2017-221550
    Acupuncture is an ancient complementary medicine which is currently used worldwide. Many serious adverse events have been reported which include a spectrum of mild-to-fatal complications. However, the level of awareness with regard to complications is still low both to physicians and patients. We report a 63-year-old who presented with acute shortness of breath 2 hours after having had acupuncture. On examination, there was absent breath sound heard on the left lung and slightly reduced breath sound on the right lung. She had type 1 respiratory failure. Urgent chest radiograph confirmed bilateral pneumothorax which was more severe on the left with tension pneumothorax and mediastinal shift. Chest tubes were inserted bilaterally after failed needle aspiration attempts. Subsequently, the pneumothoraces resolved, and she was discharged well. The bilateral pneumothoraces caused by acupuncture were curable but could have been potentially fatal if diagnosis was delayed. This case report adds to the limited current literature on the complications of acupuncture leading to bilateral pneumothoraces.
    Matched MeSH terms: Oxygen Inhalation Therapy/methods*
  13. Zinc and Metallothionein in the Development and Progression of Dental Caries
    Rahman MT, Hossain A, Pin CH, Yahya NA
    Biol Trace Elem Res, 2019 Jan;187(1):51-58.
    PMID: 29744817 DOI: 10.1007/s12011-018-1369-z
    Chronic oxidative stress and reactive oxygen species (ROS) in oral cavity as well as acidic pH on dental enamel surface due to the metabolic activities of bacterial plaque are the major contributors in the development and progression of dental caries. Along with other factors, deposition or dissolution Ca and Mg mostly determines the re- or demineralization of dental enamel. Zn plays an important role for both Ca and Mg bioavailability in oral cavity. Metallothionein (MT), a group of small molecular weight, cysteine-rich proteins (~ 7 kDa), is commonly induced by ROS, bacterial infection, and Zn. In the current review, we evaluated MT at the junction between the progression of dental caries and its etiologies that are common in MT biosynthesis.
    Matched MeSH terms: Reactive Oxygen Species/metabolism
  14. Metabolic Syndrome and Its Effect on the Brain: Possible Mechanism
    Arshad N', Lin TS, Yahaya MF
    CNS Neurol Disord Drug Targets, 2018;17(8):595-603.
    PMID: 30047340 DOI: 10.2174/1871527317666180724143258
    BACKGROUND & OBJECTIVE: Metabolic syndrome (MetS) is an interconnected group of physiological, biochemical, clinical and metabolic factors that directly increase the risk of cardiovascular disease, type 2 diabetes mellitus (T2DM) and mortality. Rising evidence suggests that MetS plays a significant role in the progression of Alzheimer's disease and other neurodegenerative diseases. Nonetheless, the factors linking this association has not yet been elucidated. As we are facing an increasing incidence of obesity and T2DM in all stages of life, understanding the association of MetS and neurodegenerative diseases is crucial to lessen the burden of the disease.

    CONCLUSION: In this review, we will discuss the possible mechanisms which may relate the association between MetS and cognitive decline which include vascular damages, elevation of reactive oxygen species (ROS), insulin resistance and low-grade inflammation.

    Matched MeSH terms: Reactive Oxygen Species/metabolism
  15. Algorithms that eliminate the effects of calibration artefact and trial-imposed offsets of Masimo oximeter in BOOST-NZ trial
    Zahari M, Lee DS, Darlow BA
    J Clin Monit Comput, 2016 Oct;30(5):669-78.
    PMID: 26282827 DOI: 10.1007/s10877-015-9752-1
    The displayed readings of Masimo pulse oximeters used in the Benefits Of Oxygen Saturation Targeting (BOOST) II and related trials in very preterm babies were influenced by trial-imposed offsets and an artefact in the calibration software. A study was undertaken to implement new algorithms that eliminate the effects of offsets and artefact. In the BOOST-New Zealand trial, oxygen saturations were averaged and stored every 10 s up to 36 weeks' post-menstrual age. Two-hundred and fifty-seven of 340 babies enrolled in the trial had at least two weeks of stored data. Oxygen saturation distribution patterns corresponding with a +3 % or -3 % offset in the 85-95 % range were identified together with that due to the calibration artefact. Algorithms involving linear and quadratic interpolations were developed, implemented on each baby of the dataset and validated using the data of a UK preterm baby, as recorded from Masimo oximeters with the original software and a non-offset Siemens oximeter. Saturation distributions obtained were compared for both groups. There were a flat region at saturations 85-87 % and a peak at 96 % from the lower saturation target oximeters, and at 93-95 and 84 % respectively from the higher saturation target oximeters. The algorithms lowered the peaks and redistributed the accumulated frequencies to the flat regions and artefact at 87-90 %. The resulting distributions were very close to those obtained from the Siemens oximeter. The artefact and offsets of the Masimo oximeter's software had been addressed to determine the true saturation readings through the use of novel algorithms. The implementation would enable New Zealand data be included in the meta-analysis of BOOST II trials, and be used in neonatal oxygen studies.
    Matched MeSH terms: Oxygen/metabolism
  16. Fulltext Nanotechnology in drug delivery gaining new perspectives in respiratory diseases
    Dua K, Madan JR, Chellappan DK, Gupta G
    Panminerva Med, 2018 09;60(3):135-136.
    PMID: 30176702 DOI: 10.23736/S0031-0808.18.03442-0
    Matched MeSH terms: Reactive Oxygen Species/chemistry
  17. Borg CR-10 scale as a new approach to monitoring office exercise training
    Shariat A, Cleland JA, Danaee M, Alizadeh R, Sangelaji B, Kargarfard M, et al.
    Work, 2018;60(4):549-554.
    PMID: 30103362 DOI: 10.3233/WOR-182762
    BACKGROUND: There are many potential training exercises for office workers in an attempt to prevent musculoskeletal disorders. However, to date a suitable tool to monitor the perceived exertion of those exercises does not exist.

    OBJECTIVE: The primary objective of this study was to examine the validity and reliability of the Borg CR-10 scale to monitor the perceived exertion of office exercise training.

    METHODS: The study involved 105 staff members employed in a government office with an age range from 25 to 50 years. The Borg CR-10 scale was self-administered two times, with an interval of two weeks in order to evaluate the accuracy of the original findings with a retest. Face validity and content validity were also examined.

    RESULTS: Reliability was found to be high for the Borg CR-10 scale (0.898). Additionally a high correlation between the Borg CR-10 scale and Visual Analog Scale (VAS) was identified (rs = 0.754, P 

    Matched MeSH terms: Oxygen Consumption/physiology
  18. Fulltext Poultry Slaughterhouse Wastewater Treatment Using Submerged Fibers in an Attached Growth Sequential Batch Reactor
    Aziz HA, Puat NNA, Alazaiza MYD, Hung YT
    Int J Environ Res Public Health, 2018 08 13;15(8).
    PMID: 30104522 DOI: 10.3390/ijerph15081734
    In this study, a sequential batch reactor (SBR) with different types of fibers was employed for the treatment of poultry slaughterhouse wastewater. Three types of fibers, namely, juite fiber (JF), bio-fringe fiber (BF), and siliconised conjugated polyester fiber (SCPF), were used. Four SBR experiments were conducted, using the fibers in different reactors, while the fourth reactor used a combination of these fibers. The treatment efficiency of the different reactors with and without fibers on biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia-nitrogen (NH₃-N), phosphorus (P), nitrite (NO₂), nitrate (NO₃), total suspended solids (TSS), and oil-grease were evaluated. The removal efficiency for the reactors with fibers was higher than that of the reactor without fibers for all pollutants. The treated effluent had 40 mg/L BOD₅ and 45 mg/L COD with an average removal efficiency of 96% and 93%, respectively, which meet the discharge limits stated in the Environmental Quality Act in Malaysia.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  19. Modulation of age related protein expression changes by gelam honey in cardiac mitochondrial rats
    Hasenan SM, Karsani SA, Jubri Z
    Exp Gerontol, 2018 11;113:1-9.
    PMID: 30248357 DOI: 10.1016/j.exger.2018.09.001
    Aging is characterized by progressive decline in biochemical and physiological functions. According to the free radical theory of aging, aging results from oxidative damage due to the accumulation of excess reactive oxygen species (ROS). Mitochondria are the main source of ROS production and are also the main target for ROS. Therefore, a diet high in antioxidant such as honey is potentially able to protect the body from ROS and oxidative damage. Gelam honey is higher in flavonoid content and phenolic compounds compared to other local honey. This study was conducted to determine the effects of gelam honey on age related protein expression changes in cardiac mitochondrial rat. A total of 24 Sprague-Dawley male rats were divided into two groups: the young group (2 months old), and aged group (19 months old). Each group were then subdivided into two groups: control group (force-fed with distilled water), and treatment group (force-fed with gelam honey, 2.5 g/kg), and were treated for 8 months. Comparative proteomic analysis of mitochondria from cardiac tissue was then performed by high performance mass spectrometry (Q-TOF LCMS/MS) followed by validation of selected proteins by Western blotting. Proteins were identified using Spectrum Mill software and were subjected to stringent statistical analysis. A total of 286 proteins were identified in the young control group (YC) and 241 proteins were identified in the young gelam group (YG). In the aged group, a total of 243 proteins were identified in control group (OC), and 271 proteins in gelam group (OG). Comparative proteome profiling identified 69 proteins with different abundance (p 
    Matched MeSH terms: Reactive Oxygen Species/metabolism*
  20. Fulltext Biohydrogen Production by Antarctic Psychrotolerant Klebsiella sp. ABZ11
    Mohammed A, Abdul-Wahab MF, Hashim M, Omar AH, Md Reba MN, Muhamad Said MF, et al.
    Pol J Microbiol, 2018 11 20;67(3):283-290.
    PMID: 30451444 DOI: 10.21307/pjm-2018-033
    Lower temperature biohydrogen production has always been attractive, due to the lower energy requirements. However, the slow metabolic rate of psychrotolerant biohydrogen-producing bacteria is a common problem that affects their biohydrogen yield. This study reports on the improved substrate synthesis and biohydrogen productivity by the psychrotolerant Klebsiella sp. strain ABZ11, isolated from Antarctic seawater sample. The isolate was screened for biohydrogen production at 30°C, under facultative anaerobic condition. The isolate is able to ferment glucose, fructose and sucrose with biohydrogen production rate and yield of 0.8 mol/l/h and 3.8 mol/g, respectively at 10 g/l glucose concentration. It also showed 74% carbohydrate uptake and 95% oxygen uptake ability, and a wide growth temperature range with optimum at 37°C. Klebsiella sp. ABZ11 has a short biohydrogen production lag phase, fast substrate uptake and is able to tolerate the presence of oxygen in the culture medium. Thus, the isolate has a potential to be used for lower temperature biohydrogen production process.
    Matched MeSH terms: Oxygen/metabolism
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