Displaying publications 1 - 20 of 1074 in total

  1. Khoo SB
    Malays Fam Physician, 2007;2(2):58-63.
    PMID: 25606082 MyJurnal
    Recommendation of oxygen therapy must include clear indication and benefits of its use, appropriate prescription, vigilant monitoring and appropriate methods of delivery. Home oxygen therapy is expensive, inconvenient and cumbersome; it should be recommended only if benefits outweigh the disadvantages and adverse effects of oxygen. GPs play an important supportive and supervisory role in the use of long-term oxygen therapy (LTOT) to improve mortality of patients with chronic hypoxaemia. Prescription of short burst oxygen therapy (SBOT) for palliation of breathlessness is without clear evidence of its efficacy. GPs can prescribe SBOT when other secondary causes of breathlessness are excluded or treated, when breathlessness is not relieved by other treatments and if an improvement can be documented in patients.
    Matched MeSH terms: Oxygen Inhalation Therapy*
  2. Nusrat Aman AM, Selvarajoo A, Lau TL, Chen WH
    Chemosphere, 2023 Feb;313:137477.
    PMID: 36509190 DOI: 10.1016/j.chemosphere.2022.137477
    The use of sustainable materials in the construction industry has been on the rise recently. Studies have proven that the use of conventional concrete and its raw materials has a negative impact on the environment. Research on incorporating biochar as a supplementary cementitious material has been recently evolving and has shown that the attributes of biochar are highly affected by the pyrolysis parameters. These attributes have enhanced the properties of biochar concrete and mortar composite. This paper identifies the different physiochemical properties exhibited by palm kernel shell biochar through optimization by response surface methodology. Focusing on some of the properties of biochar that have proven beneficial when used as a cement replacement. Very limited research has used optimization tools for the production of biochar with the intention of using it as a cement substitute. Pyrolysis was conducted by a tubular furnace at different temperature ranges from 200 °C to 800 °C. The biomass and biochar have been analyzed with TGA and FESEM-EDX. The targeted biochar properties and selected responses are the yield, carbon, oxygen, silica, and potassium content. The optimized parameters obtained are 409 °C, 15 °C/min, 120 min with responses of 38.2% yield, 73.37% carbon, 25.48% oxygen, 0.39% potassium and 0.44% silica. Thermal properties of the palm kernel shell biochar affected by the pyrolysis factors such as temperature, heating rate and residence time have also been discussed. In conclusion, this study supports and encourages the use of palm waste, which is abundant in Malaysia, as a supplementary cementitious material to promote sustainable growth in construction.
    Matched MeSH terms: Oxygen
  3. Chow LC, Puah SH, Tiong XT, Aloysious NS, Leong TS, Chew LP
    J R Coll Physicians Edinb, 2021 Sep;51(3):253-256.
    PMID: 34528613 DOI: 10.4997/JRCPE.2021.309
    Haemoglobin (Hb) Cheverly is a rare, low oxygen affinity haemoglobinopathy. It is a result of point mutation at the 45 codon of the beta globin genes that leads to substitution of phenylalanine by serine. It is characterised by spuriously low peripheral oxygen saturation with normal arterial oxygen saturation. We describe a family of three with Hb Cheverly in Sarawak General Hospital, Malaysia. It was discovered through incidental finding during hospital admission for unrelated complaints. Laboratory testing revealed abnormal haemoglobin detected at the C window of the high performance liquid chromatography. Subsequent DNA analysis detected replacement of thymidine by cytosine at the beta globin genes. Hb Cheverly may or may not have clinical significance as most of the patients live a normal life; however, it is crucial for us to make early diagnosis to prevent unnecessary extensive investigations for hypoxaemia detected via pulse oximetry, especially in the midst of COVID-19 pandemic.
    Matched MeSH terms: Oxygen
  4. Munksgaard NC, Kurita N, Sánchez-Murillo R, Ahmed N, Araguas L, Balachew DL, et al.
    Sci Rep, 2019 10 08;9(1):14419.
    PMID: 31595004 DOI: 10.1038/s41598-019-50973-9
    We present precipitation isotope data (δ2H and δ18O values) from 19 stations across the tropics collected from 2012 to 2017 under the Coordinated Research Project F31004 sponsored by the International Atomic Energy Agency. Rainfall samples were collected daily and analysed for stable isotopic ratios of oxygen and hydrogen by participating laboratories following a common analytical framework. We also calculated daily mean stratiform rainfall area fractions around each station over an area of 5° x 5° longitude/latitude based on TRMM/GPM satellite data. Isotope time series, along with information on rainfall amount and stratiform/convective proportions provide a valuable tool for rainfall characterisation and to improve the ability of isotope-enabled Global Circulation Models to predict variability and availability of inputs to fresh water resources across the tropics.
    Matched MeSH terms: Oxygen; Oxygen Isotopes
  5. Qaid E, Zakaria R, Sulaiman SF, Yusof NM, Shafin N, Othman Z, et al.
    Hum Exp Toxicol, 2017 Dec;36(12):1315-1325.
    PMID: 28111974 DOI: 10.1177/0960327116689714
    Impairment of memory is one of the most frequently reported symptoms during sudden hypoxia exposure in human. Cortical atrophy has been linked to the impaired memory function and is suggested to occur with chronic high-altitude exposure. However, the precise molecular mechanism(s) of hypoxia-induced memory impairment remains an enigma. In this work, we review hypoxia-induced learning and memory deficit in human and rat studies. Based on data from rat studies using different protocols of continuous hypoxia, we try to elicit potential mechanisms of hypobaric hypoxia-induced memory deficit.
    Matched MeSH terms: Oxygen*
  6. Kue CS, Ng SY, Voon SH, Kamkaew A, Chung LY, Kiew LV, et al.
    Photochem. Photobiol. Sci., 2018 Nov 01;17(11):1691-1708.
    PMID: 29845993 DOI: 10.1039/c8pp00113h
    BODIPYs are photosensitizers activatable by light to generate highly reactive singlet oxygen (1O2) from molecular oxygen, leading to tissue damage in the photoirradiated region. Despite their extraordinary photophysical characteristics, they are not featured in clinical photodynamic therapy. This review discusses the recent advances in the design and/or modifications of BODIPYs since 2013, to improve their potential in photodynamic cancer therapy and related areas.
    Matched MeSH terms: Oxygen; Singlet Oxygen
  7. Abdulhameed EA, Al-Rawi NH, Omar M, Khalifa N, Samsudin ABR
    PeerJ, 2022;10:e12951.
    PMID: 35261818 DOI: 10.7717/peerj.12951
    BACKGROUND: Titanium dioxide dental implants have a controversial effect on reactive oxygen species (ROS) production. ROS is necessary for cellular signal transmission and proper metabolism, but also has the ability to cause cell death as well as DNA, RNA, and proteins damage by excessive oxidative stress. This study aimed to systematically review the effect of titanium dioxide dental implant-induced oxidative stress and its role on the osteogenesis-angiogenesis coupling in bone remodeling.

    METHODS: This systematic review was performed conforming to preferred reporting items for systematic review and meta-analysis (PRISMA) model. Four different databases (PubMed, Science Direct, Scopus and Medline databases) as well as manual searching were adopted. Relevant studies from January 2000 till September 2021 were retrieved. Critical Appraisal Skills Programme (CASP) was used to assess the quality of the selected studies.

    RESULTS: Out of 755 articles, only 14 which met the eligibility criteria were included. Six studies found that titanium dioxide nanotube (TNT) reduced oxidative stress and promoted osteoblastic activity through its effect on Wnt, mitogen-activated protein kinase (MAPK) and forkhead box protein O1 (FoxO1) signaling pathways. On the other hand, three studies confirmed that titanium dioxide nanoparticles (TiO2NPs) induce oxidative stress, reduce ostegenesis and impair antioxidant defense system as a significant negative correlation was found between decreased SIR3 protein level and increased superoxide (O2 •-). Moreover, five studies proved that titanium implant alloy enhances the generation of ROS and induces cytotoxicity of osteoblast cells via its effect on NOX pathway.

    CONCLUSION: TiO2NPs stimulate a wide array of oxidative stress related pathways. Scientific evidence are in favor to support the use of TiO2 nanotube-coated titanium implants to reduce oxidative stress and promote osteogenesis in bone remodeling. To validate the cellular and molecular cross talk in bone remodeling of the present review, well-controlled clinical trials with a large sample size are required.

    Matched MeSH terms: Reactive Oxygen Species/metabolism
  8. Kow CS, Ramachandram DS, Hasan SS
    J Asthma, 2023 Feb;60(2):422-423.
    PMID: 35315746 DOI: 10.1080/02770903.2022.2056701
    Matched MeSH terms: Oxygen; Oxygen Inhalation Therapy
  9. Salehmin MN, Annuar MS, Chisti Y
    Bioprocess Biosyst Eng, 2013 Nov;36(11):1527-43.
    PMID: 23539203 DOI: 10.1007/s00449-013-0943-1
    This review is focused on the production of microbial lipases by high cell density fermentation. Lipases are among the most widely used of the enzyme catalysts. Although lipases are produced by animals and plants, industrial lipases are sourced almost exclusively from microorganisms. Many of the commercial lipases are produced using recombinant species. Microbial lipases are mostly produced by batch and fed-batch fermentation. Lipases are generally secreted by the cell into the extracellular environment. Thus, a crude preparation of lipases can be obtained by removing the microbial cells from the fermentation broth. This crude cell-free broth may be further concentrated and used as is, or lipases may be purified from it to various levels. For many large volume applications, lipases must be produced at extremely low cost. High cell density fermentation is a promising method for low-cost production: it allows a high concentration of the biomass and the enzyme to be attained rapidly and this eases the downstream recovery of the enzyme. High density fermentation enhances enzyme productivity compared with the traditional submerged culture batch fermentation. In production of enzymes, a high cell density is generally achieved through fed-batch operation, not through perfusion culture which is cumbersome. The feeding strategies used in fed-batch fermentations for producing lipases and the implications of these strategies are discussed. Most lipase-producing microbial fermentations require oxygen. Oxygen transfer in such fermentations is discussed.
    Matched MeSH terms: Oxygen/metabolism*
  10. Pendashteh AR, Fakhru'l-Razi A, Chuah TG, Radiah AB, Madaeni SS, Zurina ZA
    Environ Technol, 2010 Oct;31(11):1229-39.
    PMID: 21046953 DOI: 10.1080/09593331003646612
    Produced water or oilfield wastewater is the largest volume ofa waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m(-3) d(-1), 1.8 kg COD m(-3) d(-1) and 3.6 kg COD m(-3) d(-1)) and different total dissolved solids (TDS) concentration (35,000 mg L(-1), 100,000 mg L(-1), 150,000 mg L(-1), 200,000 mg L(-1) and 250,000 mg L(-1)). It was found that with an OLR of 0.9 kg COD m(-3) d(-1) and 1.8 kg COD m(-3) d(-1), average oil and grease (O&G) concentrations in the effluent were 7 mg L(-1) and 12 mg L(-1), respectively. At TDS concentration of 35,000 mg L(-1) and at an OLR of 1.8 kg COD m(-3)d(-1), COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L(-1), COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83%, and 85%, respectively.
    Matched MeSH terms: Oxygen/metabolism*
  11. Hasanpourghadi M, Looi CY, Pandurangan AK, Sethi G, Wong WF, Mustafa MR
    Curr Drug Targets, 2017;18(9):1086-1094.
    PMID: 27033190 DOI: 10.2174/1389450117666160401124842
    Phytometabolites are functional elements derived from plants and most of them exhibit therapeutic characteristics such as anti-cancer, anti-inflammatory and anti-oxidant effects. Phytometabolites exert their anti-cancer effect by targeting multiple signaling pathways. One of the remarkable phenomena targeted by phytometabolites is the Warburg effect. The Warburg effect describes the observation that cancer cells exhibit an increased rate of glycolysis and aberrant redox activity compared to normal cells. This phenomenon promotes further cancer development and progression. Recent observations revealed that some phytometabolites could target metabolic-related enzymes (e.g. Hexokinase, Pyruvate kinase M2, HIF-1) in cancer cells, with little or no harm to normal cells. Since hyper-proliferation of cancer cells is fueled by higher cellular metabolism, phytometabolites targeting these metabolic pathways can create synergistic crosstalk with induced apoptotic pathways and sensitize cancer cells to chemotherapeutic agents. In this review, we discuss phytometabolites that target the Warburg effect and the underlying molecular mechanism that leads to tumor growth suppression.
    Matched MeSH terms: Oxygen/metabolism*
  12. Izyan Munirah M. Zaideen, Suhaimi Suratman, Norhayati Mohd Tahir
    Sains Malaysiana, 2017;46:1513-1520.
    This study investigates the spatial variation of water quality parameters in Sungai Setiu Basin at ten different locations from March 2010 to February 2011. The water quality was assessed using the Water Quality Index by Malaysian Department of Environment (DOE-WQI) and classified according to the Malaysia Interim National Water Quality Standard (INWQS). Six water quality parameters embedded in the DOE-WQI were dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), pH, ammoniacal nitrogen (AN) and total suspended solid (TSS). In addition, this study also examined the changes in water quality over the past 10 years by comparing the present water quality to the previous works. The overall mean WQI value obtained was 84.0 which indicate that the Sungai Setiu basin is in clean condition and all measured water quality parameters gave value within the permissible limits of the INWQS classification except for pH which fall in Class III. It can be concluded that water quality in Sungai Setiu does not varies greatly over a decade. Hence continuous monitoring is needed to improve the water quality and minimize water pollution.
    Matched MeSH terms: Oxygen; Biological Oxygen Demand Analysis
  13. Dadrasnia A, Azirun MS, Ismail SB
    BMC Biotechnol, 2017 Nov 28;17(1):85.
    PMID: 29179747 DOI: 10.1186/s12896-017-0395-9
    BACKGROUND: When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH.

    RESULTS: Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI.

    CONCLUSIONS: Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

    Matched MeSH terms: Oxygen/analysis; Oxygen/metabolism; Biological Oxygen Demand Analysis*
  14. Thamrin V, Saugstad OD, Tarnow-Mordi W, Wang YA, Lui K, Wright IM, et al.
    J Pediatr, 2018 10;201:55-61.e1.
    PMID: 30251639 DOI: 10.1016/j.jpeds.2018.05.053
    OBJECTIVE: To determine rates of death or neurodevelopmental impairment (NDI) at 2 years corrected age (primary outcome) in children <32 weeks' gestation randomized to initial resuscitation with a fraction of inspired oxygen (FiO2) value of 0.21 or 1.0.

    STUDY DESIGN: Blinded assessments were conducted at 2-3 years corrected age with the Bayley Scales of Infant and Toddler Development, Third Edition or the Ages and Stages Questionnaire by intention to treat.

    RESULTS: Of the 290 children enrolled, 40 could not be contacted and 10 failed to attend appointments. Among the 240 children for whom outcomes at age 2 years were available, 1 child had a lethal congenital anomaly, 1 child had consent for follow-up withdrawn, and 23 children died. The primary outcome, which was available in 238 (82%) of those randomized, occurred in 47 of the 117 (40%) children assigned to initial FiO2 0.21 and in 38 of the 121 (31%) assigned to initial FiO2 1.0 (OR, 1.47; 95% CI, 0.86-2.5; P = .16). No difference in NDI was found in 215 survivors randomized to FiO2 0.21 vs 1.0 (OR, 1.26; 95% CI, 0.70-2.28; P = .11). In post hoc exploratory analyses in the whole cohort, children with a 5-minute blood oxygen saturation (SpO2) <80% were more likely to die or to have NDI (OR, 1.85; 95% CI, 1.07-3.2; P = .03).

    CONCLUSIONS: Initial resuscitation of infants <32 weeks' gestation with initial FiO2 0.21 had no significant effect on death or NDI compared with initial FiO2 1.0. Further evaluation of optimum initial FiO2, including SpO2 targeting, in a large randomized controlled trial is needed.

    TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Network Registry ACTRN 12610001059055 and the National Malaysian Research Registry NMRR-07-685-957.

    Matched MeSH terms: Oxygen/administration & dosage*; Oxygen/blood; Oxygen Inhalation Therapy/methods*
  15. Al-Shididi S, Henze M, Ujang Z
    Water Sci Technol, 2003;48(11-12):327-35.
    PMID: 14753553
    The objective of this study was to assess the feasibility of the Sequencing Batch Reactor (SBR) system for implementation in Malaysia. Theoretical, field, laboratory investigations, and modelling simulations have been carried out. The results of the study indicated that the SBR system was robust, relatively cost-effective, and efficient under Malaysian conditions. However, the SBR system requires highly skilled operators and continuous monitoring. This paper also attempted to identify operating conditions for the SBR system, which optimise both the removal efficiencies and the removal rates. The removal efficiencies could reach 90-96% for COD, up to 92% for TN, and 95% for SS. An approach to estimate a full operational cycle time, to estimate the de-sludging rate, and to control the biomass in the sludge has also been developed. About 4 hours react time was obtained, as 2.25 hours of nitrification with aerated slow fill and 1.75 hour of denitrification with HAc addition as an additional carbon source. Inefficient settling was one of the problems that affect the SBR effluent quality. The settling time was one hour for achieving Standard B (effluent quality) and 2 hours for Standard A.
    Matched MeSH terms: Oxygen/analysis; Oxygen/chemistry
  16. Christwardana M, Yoshi LA, Setyonadi I, Maulana MR, Fudholi A
    Enzyme Microb Technol, 2021 Sep;149:109831.
    PMID: 34311895 DOI: 10.1016/j.enzmictec.2021.109831
    In this study, yeast microbial fuel cells (MFCs) were established as biosensors for in-situ monitoring of dissolved oxygen (DO) levels in environmental waters, with yeast and glucose substrates acting as biocatalyst and fuel, respectively. Diverse environmental factors, such as temperature, pH and conductivity, were considered. The sensor performance was first tested with distilled water with different DO levels ranging from 0 mg/L to 8 mg/L and an external resistance of 1000 Ω. The relationship between DO and current density was non-linear (exponential). This MFC capability was further explored under different environmental conditions (pH, temperature and conductivity), and the current density produced was within the range of 0.14-34.88 mA/m2, which increased with elevated DO concentration. The resulting regression was y = 1.3051e0.3548x, with a regression coefficient (R2) = 0.71, indicating that the MFC-based DO meter was susceptible to interference. When used in environmental water samples, DO measurements using MFC resulted in errors ranging from 6.25 % to 15.15 % when compared with commercial DO meters. The simple yeast-based MFC sensors demonstrate promising prospects for future monitoring in a variety of areas, including developing countries and remote locations.
    Matched MeSH terms: Oxygen/analysis; Biological Oxygen Demand Analysis
  17. Alvankarian J, Majlis BY
    PLoS One, 2015;10(3):e0119658.
    PMID: 25747514 DOI: 10.1371/journal.pone.0119658
    Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity.
    Matched MeSH terms: Oxygen/chemistry*
  18. Zahari NK, Sheikh Ab Hamid S, Yusof N
    Cell Tissue Bank, 2015 Mar;16(1):55-63.
    PMID: 24647964 DOI: 10.1007/s10561-014-9438-9
    Preserved human amniotic membrane either air dried or glycerol preserved has been used effectively to treat superficial and partial thickness wounds without leaving any obvious hypertrophic scar. The preserved amnion, sterilised by ionising radiation, is known as an effective barrier for heat, fluid and protein loss while adheres nicely on wound. Air drying slightly reduced the oxygen transmission rate (OTR) of the amnion and the value significantly dropped after 15 kGy (p < 0.05). Glycerol preservation significantly reduced (p < 0.05) the OTR indicating less oxygen transmitted through the well structured cells of the amnion. Increase in the OTR with the increasing radiation doses up to 35 kGy possibly due to direct effects of radiation that resulted in large intercellular gaps. Both preservation methods significantly increased (p < 0.05) the water vapour transmission rate (WVTR). However, the low WVTR in the air dried amnion at 15 and 25 kGy was postulated due to cross-linking of collagen. Changes in the biophysical properties can be linked to direct and indirect effects of radiation on collagen bundles. The radiation dose of 25 kGy caused no adverse effect on biophysical properties hence it is still acceptable to sterilize both the air dried and the glycerol preserved amnions.
    Matched MeSH terms: Oxygen/metabolism*
  19. Abdul Rahim A, Idris MH, Kamal AH, Wong SK, Arshad A
    Pak J Biol Sci, 2012 Jul 01;15(13):629-34.
    PMID: 24218932
    The Condition Index (CI) is a method to measure overall health of fish and that has been applied to estimate the effect that different environmental factors have on clam meat quality. The CI of local mangrove clam Polymesoda expansa in Kelulit, Miri Sarawak was determined from October 2010 to November 2011. Condition index that is generally used to characterize the physiological activity of organisms, varied from 1.8% in December 2010 to 3.4% in October 2011, with low values observed during the spawning period. The clam attained their best condition in quality of flesh weight during July-October. In present study, the CI showed a clear relationship with the reproductive cycle of P. expansa. However, no significant correlation (p > 0.05) was found between CI and the different physicochemical parameter of seawater. The data presented is necessary for developing sustainable management strategies and broodstock selection for the species which is crucial in aquaculture development.
    Matched MeSH terms: Oxygen/metabolism
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