Displaying publications 541 - 560 of 1115 in total

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  1. Mislia Othman, Muhammad Azrul Zabidi
    MyJurnal
    This review paper aims to present an overview of the development of blood substitute particularly red blood cell substitute or artificial oxygen carrier. Knowledge on human blood inspired from the understanding of human blood circulation system. Ibn Nafis was first to describe that blood flow through respiratory system before entering the heart. This finding denied the claim that tiny pores present within the septum of the heart. Then, William Harvey further described human cardiovascular system in detail and contributed to better understanding on the roles of blood in body. Several blood transfusions were attempted using blood collected from human, animal and other blood substitutes such as milk before the practice was banned for almost 150 years in Europe. Major discoveries on blood group and antibody reaction have made blood transfusion safer. However, several issues and challenges have re-triggered the exploration to develop red cell substitutes. Two approaches have been taken to develop the red blood cell substitute which are classified into biological and chemical based oxygen carriers. The earliest efforts have been on haemoglobin based oxygen carrier (HBOC) and perfluorocarbon (PFC) while the recent developement are on polymer-based oxygen carrier and in-vitro stem cell derived red blood cell.
    Matched MeSH terms: Oxygen
  2. Tan K, Zhang H, Lim LS, Ma H, Li S, Zheng H
    Front Immunol, 2019;10:3041.
    PMID: 32010132 DOI: 10.3389/fimmu.2019.03041
    Carotenoids are biologically active pigments that are well-known to enhance the defense and immunity of the vertebrate system. However, in invertebrates, the role of carotenoids in immunity is not clear. Therefore, this study aims to review the scientific evidence for the role of carotenoids in invertebrate immunization. From the analysis of published literatures and recent studies from our laboratory, it is obvious that carotenoids are involved in invertebrate immunity in two ways. On the one hand, carotenoids can act as antioxidant enzymes to remove singlet oxygen, superoxide anion radicals, and hydroxyl radicals, thereby reducing SOD activity and reducing the cost of immunity. In some organisms, carotenoids have been shown to promote SOD activity by up-regulating the expression of the ZnCuSOD gene. Carotenoids, on the other hand, play a role in the expression and regulation of many genes involved in invertebrate immunity, including thioredoxins (TRX), peptidoglycan recognition receptor proteins (PGRPs), ferritins, prophenoloxidase (ProPO), vitellogenin (Vg), toll-like receptor (TLRs), heat shock proteins (HSPs), and CuZnSOD gene. The information in this review is very useful for updating our understanding of the progress of carotenoid research in invertebrate immunology and to help identify topics for future topics.
    Matched MeSH terms: Singlet Oxygen
  3. Nguyen DH, Vo TNN, Nguyen NT, Ching YC, Hoang Thi TT
    PLoS One, 2020;15(9):e0239360.
    PMID: 32960911 DOI: 10.1371/journal.pone.0239360
    Exploiting plant extracts to form metallic nanoparticles has been becoming the promising alternative routes of chemical and physical methods owing to environmentally friendly and abundantly renewable resources. In this study, Momordica charantia and Psidium guajava leaf extract (MC.broth and PG.broth) are exploited to fabricate two kinds of biogenic silver nanoparticles (MC.AgNPs and PG.AgNPs). Phytoconstituent screening is performed to identify the categories of natural compounds in MC.broth and PG.broth. Both extracts contain wealthy polyphenols which play a role of reducing agent to turn silver (I) ions into silver nuclei. Trace alkaloids, rich saponins and other oxygen-containing compounds creating the organic corona surrounding nanoparticles act as stabilizing agents. MC.AgNPs and PG.AgNPs are characterized by UV-vis and FTIR spectrophotometry, EDS and TEM techniques. FTIR spectra indicate the presence of O-H, C = O, C-O-C and C = C groups on the surface of silver nanoparticles which is corresponded with three elements of C, O and Ag found in EDS analysis. TEM micrographs show the spherical morphology of MC.AgNPs and PG.AgNPs. MC.AgNPs were 17.0 nm distributed in narrow range of 5-29 nm, while the average size of PG.AgNPs were 25.7 nm in the range of 5-53 nm. Further, MC.AgNPs and PG.AgNPs exhibit their effectively inhibitory ability against A. niger, A. flavus and F. oxysporum as dose-dependence. Altogether, MC.AgNPs and PG.AgNPs will have much potential in scaled up production and become the promising fungicides for agricultural applications.
    Matched MeSH terms: Oxygen Compounds
  4. Tang KS
    Curr Diabetes Rev, 2021;17(4):496-502.
    PMID: 33045978 DOI: 10.2174/1573399816999201012201111
    BACKGROUND: Diabetes mellitus is a metabolic disease that requires immediate attention. Oxidative stress that leads to the generation of reactive oxygen species is a contributing factor to the disease progression. Yttrium oxide nanoparticles (Y2O3 NPs) have a profound effect on alleviating oxidative damage.

    METHODS: The literature related to Y2O3 NPs and oxidative stress has been thoroughly searched using PubMed and Scopus databases and relevant studies from inception until August 2020 were included in this scoping review.

    RESULTS: Y2O3 NPs altered oxidative stress-related biochemical parameters in different disease models including diabetes.

    CONCLUSION: Although Y2O3 NPs are a promising antidiabetic agent due to their antioxidant and anti- inflammatory properties, more studies are required to further elucidate the pharmacological and toxicological properties of these nanoparticles.

    Matched MeSH terms: Reactive Oxygen Species
  5. Venkatachalam K, Vinayagam R, Arokia Vijaya Anand M, Isa NM, Ponnaiyan R
    Toxicol Res (Camb), 2020 Feb;9(1):2-18.
    PMID: 32440334 DOI: 10.1093/toxres/tfaa004
    1,2-dimethylhydrazine (DMH) is a member in the class of hydrazines, strong DNA alkylating agent, naturally present in cycads. DMH is widely used as a carcinogen to induce colon cancer in animal models. Exploration of DMH-induced colon carcinogenesis in rodent models provides the knowledge to perceive the biochemical, molecular, and histological mechanisms of different stages of colon carcinogenesis. The procarcinogen DMH, after a series of metabolic reactions, finally reaches the colon, there produces the ultimate carcinogen and reactive oxygen species (ROS), which further alkylate the DNA and initiate the development of colon carcinogenesis. The preneolpastic lesions and histopathological observations of DMH-induced colon tumors may provide typical understanding about the disease in rodents and humans. In addition, this review discusses about the action of biotransformation and antioxidant enzymes involved in DMH intoxication. This understanding is essential to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH-induced animal colon carcinogenesis.
    Matched MeSH terms: Reactive Oxygen Species
  6. 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
  7. Pang KP, Baptista PM, Olszewska E, Braverman I, Carrasco-Llatas M, Kishore S, et al.
    Med J Malaysia, 2020 03;75(2):117-123.
    PMID: 32281591
    OBJECTIVE: To demonstrate SLEEP-GOAL as a more holistic and comprehensive success criterion for Obstructive Sleep Apnoea (OSA) treatment.

    METHODS: A prospective 7-country clinical trial of 302 OSA patients, who met the selection criteria, and underwent nose, palate and/or tongue surgery. Pre- and post-operative data were recorded and analysed based on both the Sher criteria (apnoea hypopnea index, AHI reduction 50% and <20) and the SLEEP-GOAL.

    RESULTS: There were 229 males and 73 females, mean age of 42.4±17.3 years, mean BMI 27.9±4.2. The mean VAS score improved from 7.7±1.4 to 2.5±1.7 (p<0.05), mean Epworth score (ESS) improved from 12.2±4.6 to 4.9±2.8 (p<0.05), mean body mass index (BMI) decreased from 27.9±4.2 to 26.1±3.7 (p>0.05), gross weight decreased from 81.9±14.3kg to 76.6±13.3kg. The mean AHI decreased 33.4±18.9 to 14.6±11.0 (p<0.05), mean lowest oxygen saturation (LSAT) improved 79.4±9.2% to 86.9±5.9% (p<0.05), and mean duration of oxygen <90% decreased from 32.6±8.9 minutes to 7.3±2.1 minutes (p<0.05). The overall success rate (302 patients) based on the Sher criteria was 66.2%. Crosstabulation of respective major/minor criteria fulfilment, based on fulfilment of two major and two minor or better, the success rate (based on SLEEP-GOAL) was 69.8%. Based solely on the Sher criteria, 63 patients who had significant blood pressure reduction, 29 patients who had BMI reduction and 66 patients who had clinically significant decrease in duration of oxygen <90% would have been misclassified as "failures".

    CONCLUSION: AHI as a single parameter is unreliable. Assessing true success outcomes of OSA treatment, requires comprehensive and holistic parameters, reflecting true end-organ injury/function; the SLEEP-GOAL meets these requirements.

    Matched MeSH terms: Oxygen
  8. Hilaluddin F, Yusoff FM, Natrah FMI, Lim PT
    Mar Environ Res, 2020 Jun;158:104935.
    PMID: 32217292 DOI: 10.1016/j.marenvres.2020.104935
    To assess the effects of environmental changes on phytoplankton community structure in a mangrove ecosystem, phytoplankton distribution in Matang mangrove, Malaysia was examined. Phytoplankton and water samples, and in situ environmental parameters from three estuaries with differing levels of disturbance were examined monthly for one year. Two species, Cyclotella choctawhatcheeana and Skeletonema costatum, were dominant in the least disturbed and moderately disturbed areas, respectively. Skeletonema costatum was also the most dominant in the most disturbed area. Significant differences in phytoplankton density and biodiversity between the least and most disturbed areas were also observed. Principle component 1 (salinity, conductivity, total solids/water transparency and nitrogenous compounds) and PC2 (dissolved oxygen, pH and temperature) explained 60.4% of the total variance. This study illustrated that changes in phytoplankton community structure in Matang mangrove estuaries were significantly correlated with environmental parameters which were in turn influenced by ecosystem disturbance levels as well as seasonal changes.
    Matched MeSH terms: Oxygen
  9. Jamain Z, Khairuddean M, Guan-Seng T
    Molecules, 2020 May 01;25(9).
    PMID: 32370000 DOI: 10.3390/molecules25092122
    A series of new hexasubstituted cyclotriphosphazene compounds (4a-j) consisting of two Schiff base linking units and different terminal substituents was successfully synthesized and characterized. The structures of these compounds were confirmed using Fourier Transform Infra-Red (FTIR), Nuclear Magnetic Resonance (NMR), and CHN elemental analysis. Polarized optical microscopy (POM) was used to determine their liquid-crystal behavior, which was then further confirmed using differential scanning calorimetry (DSC). Compounds 4a-i with heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxy, 4-carboxyphenyl, chloro, and nitro terminal ends, respectively, showed the liquid-crystal properties, whereas compound 4j with the amino group was found to be non-mesogenic. The attachment of an electron-donating group in 4j eventually give a non-mesogenic product. The study of the fire-retardant properties of these compounds was done using the limiting oxygen index (LOI). In this study, polyester resin (PE) was used as a matrix for moulding, and the LOI value of pure PE was 22.53%. The LOI value increased to 24.71% when PE was incorporated with 1 wt.% of hexachlorocyclotriphosphazene (HCCP), thus indicating that HCCP has a good fire-retardant properties. The result showed that all the compounds have good agreement in their LOI values. Compound 4i with a nitro terminal group gave the highest LOI value of 28.37%.
    Matched MeSH terms: Oxygen
  10. A Karim SS, Takamura Y, Tue PT, Tung NT, Kazmi J, Dee CF, et al.
    Materials (Basel), 2020 Mar 04;13(5).
    PMID: 32143385 DOI: 10.3390/ma13051136
    Highly ordered vertically grown zinc oxide nanorods (ZnO NRs) were synthesized on ZnO-coated SiO2/Si substrate using zinc acetylacetonate hydrate as a precursor via a simple hydrothermal method at 85 °C. We used 0.05 M of ZnO solution to facilitate the growth of ZnO NRs and the immersion time was varied from 0.5 to 4 h. The atomic force microscopy revealed the surface roughness of ZnO seed layer used to grow the ZnO NRs. The morphology of vertically grown ZnO NRs was observed by field emission scanning electron microscopy. X-ray diffraction examination and transmission electron microscopy confirmed that the structure of highly ordered ZnO NRs was crystalline with a strong (002) peak corresponded to ZnO hexagonal wurtzite structure. The growth of highly ordered ZnO NRs was favorable due to the continuous supply of Zn2+ ions and chelating agents properties obtained from the acetylacetonate-derived precursor during the synthesis. Two-point probe current-voltage measurement and UV-vis spectroscopy of the ZnO NRs indicated a resistivity and optical bandgap value of 0.44 Ω.cm and 3.35 eV, respectively. The photoluminescence spectrum showed a broad peak centered at 623 nm in the visible region corresponded to the oxygen vacancies from the ZnO NRs. This study demonstrates that acetylacetonate-derived precursors can be used for the production of ZnO NRs-based devices with a potential application in biosensors.
    Matched MeSH terms: Oxygen
  11. Wong KA, Lam SM, Sin JC
    J Nanosci Nanotechnol, 2019 08 01;19(8):5271-5278.
    PMID: 30913844 DOI: 10.1166/jnn.2019.16816
    Shaped-controlled ZnO architectures including spherical, rod, rice-like and flower-like were fabricated via a reflux method in which the morphology, crystallinity, functional group and optical properties were tailored under different pH values in the precursor solution. The photoactivities of the prepared ZnO were evaluated under UV irradiation and the findings implied that the flower-like ZnO synthesized at pH 12 displayed superior activities on palm oil mil effluent degradation than those of other structures. The photocatalytic enhancement of flower-like ZnO was ascribed to its unique architecture, good crystallinity and superior optical properties. The flower-like ZnO with excellent photocatalytic performance have been confirmed by formation of hydroxyl radicals using a terephthalic acid-photoluminescence test. There was an optimal photocatalyst amount of 1.0 g/L, at which a maximum chemical oxygen demand removal of palm oil mill effluent was achieved under exposure of UV light. The phytotoxicity experiment via mung beans demonstrated a decrease in phytotoxicity.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  12. Oon YL, Ong SA, Ho LN, Wong YS, Dahalan FA, Oon YS, et al.
    Sci Total Environ, 2020 Jun 10;720:137370.
    PMID: 32325554 DOI: 10.1016/j.scitotenv.2020.137370
    Complete degradation of azo dye has always been a challenge due to the refractory nature of azo dye. An innovative hybrid system, constructed wetland-microbial fuel cell (CW-MFC) was developed for simultaneous azo dye remediation and energy recovery. This study investigated the effect of circuit connection and the influence of azo dye molecular structures on the degradation rate of azo dye and bioelectricity generation. The closed circuit system exhibited higher chemical oxygen demand (COD) removal and decolourisation efficiencies compared to the open circuit system. The wastewater treatment performances of different operating systems were ranked in the decreasing order of CW-MFC (R1 planted-closed circuit) > MFC (R2 plant-free-closed circuit) > CW (R1 planted-open circuit) > bioreactor (R2 plant-free-open circuit). The highest decolourisation rate was achieved by Acid Red 18 (AR18), 96%, followed by Acid Orange 7 (AO7), 67% and Congo Red (CR), 60%. The voltage outputs of the three azo dyes were ranked in the decreasing order of AR18 > AO7 > CR. The results disclosed that the decolourisation performance was significantly influenced by the azo dye structure and the moieties at the proximity of azo bond; the naphthol type azo dye with a lower number of azo bond and more electron-withdrawing groups could cause azo bond to be more electrophilic and more reductive for decolourisation. Moreover, the degradation pathway of AR18, AO7 and CR were elucidated based on the respective dye intermediate products identified through UV-Vis spectrophotometry, high-performance liquid chromatography (HPLC), and gas chromatograph-mass spectrometer (GC-MS) analyses. The CW-MFC system demonstrated high capability of decolouring azo dyes at the anaerobic anodic region and further mineralising dye intermediates at the aerobic cathodic region to less harmful or non-toxic products.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  13. Rashid NH, Zaghi S, Scapuccin M, Camacho M, Certal V, Capasso R
    Laryngoscope, 2021 02;131(2):440-447.
    PMID: 32333683 DOI: 10.1002/lary.28663
    OBJECTIVES: Intermittent hypoxemia is a risk factor for developing complications in obstructive sleep apnea (OSA) patients. The objective of this systematic review was to identify articles evaluating the accuracy of the oxygen desaturation index (ODI) as compared with the apnea-hypopnea index (AHI) and then provide possible values to use as a cutoff for diagnosing adult OSA.

    STUDY DESIGN: Systematic Review of Literature.

    METHODS: PubMed, the Cochrane Library, and SCOPUS databases were searched through November 2019.

    RESULTS: Eight studies (1,924 patients) met criteria (age range: 28-70.9 years, body mass index range: 21.9-37 kg/m2 , and AHI range: 0.5-62 events/hour). Five studies compared ODI and AHI simultaneously, and three had a week to months between assessments. Sensitivities ranged from 32% to 98.5%, whereas specificities ranged from 47.7% to 98%. Significant heterogeneity was present; however, for studies reporting data for a 4% ODI ≥ 15 events/hour, the specificity for diagnosing OSA ranged from 75% to 98%, and only one study reported the positive predictive value, which was 97%. Direct ODI and AHI comparisons were not made because of different hypopnea scoring, different oxygen desaturation categories, and different criteria for grading OSA severity.

    CONCLUSION: Significant heterogeneity exists in studies comparing ODI and AHI. Based on currently published studies, consideration should be given for diagnosing adult OSA with a 4% ODI of ≥ 15 events/hour and for recommending further evaluation for diagnosing OSA with a 4% ODI ≥ 10 events/hour. Screening with oximetry may be indicated for the detection of OSA in select patients. Further study is needed before a definitive recommendation can be made. Laryngoscope, 131:440-447, 2021.

    Matched MeSH terms: Oxygen
  14. Azman KF, Zakaria R
    Iran J Basic Med Sci, 2019 Dec;22(12):1368-1377.
    PMID: 32133053 DOI: 10.22038/IJBMS.2019.14027
    This paper reviews the potential role of honey as a therapeutic antioxidant to reduce oxidative stress and improve cognitive ageing. All articles indexed to PubMed Central (PMC) were searched using the following key words: honey, antioxidant, memory and ageing. Honey is a natural insect-derived product with therapeutic, medicinal and nutritional values. Antioxidant properties of honey quench biologically-circulating reactive oxygen species (ROS) and counter oxidative stress while restoring the cellular antioxidant defense system. Antioxidant properties of honey may complement its nootropic effects to reduce cognitive ageing.
    Matched MeSH terms: Reactive Oxygen Species
  15. Hue YL, Lum LCS, Ahmad SH, Tan SS, Wong SY, Nathan AM, et al.
    Singapore Med J, 2020 Jun 02.
    PMID: 32480437 DOI: 10.11622/smedj.2020084
    INTRODUCTION: Chest physiotherapy (CPT) may benefit children aged < 5 years who suffer from lower respiratory tract infection (LRTI). However, its effects are technique-dependent. This study aimed to determine whether mechanical CPT using the LEGA-Kid® mechanical percussion device is superior to manual CPT in children with LRTI.

    METHODS: Children aged 5 months to 5 years who were admitted and referred for CPT from January to April 2017 were randomised to either manual CPT or mechanical CPT with LEGA-Kid®. Outcomes measured at pre-intervention and 2 hours post-intervention were respiratory rate (RR), oxygen saturation and modified Respiratory Distress Assessment Instrument (mRDAI) score.

    RESULTS: All 30 enrolled patients had significant reduction in post-intervention RR and mRDAI scores. There was an 8% reduction in RR for the manual CPT group (p = 0.002) and a 16.5% reduction in the mechanical CPT group (p = 0.0001), with a significantly greater reduction in the latter (p = 0.024). mRDAI scores decreased by 2.96 in the manual group (p = 0.0001) and 3.62 in the mechanical group (p = 0.002), with no significant difference between the groups. There was no significant improvement in oxygen saturation, and no adverse events were observed after CPT.

    CONCLUSION: Children receiving either manual or mechanical CPT showed improvements in respiratory distress symptoms with no adverse effects. A combined strategy of nebulised hypertonic saline followed by CPT for LRTI removes airway secretions and results in improvements of moderately severe respiratory distress. The LEGA-Kid mechanical CPT method was superior in reducing RR.

    Matched MeSH terms: Oxygen
  16. Arul P, Gowthaman NSK, John SA, Lim HN
    ACS Omega, 2020 Jun 23;5(24):14242-14253.
    PMID: 32596560 DOI: 10.1021/acsomega.9b03829
    Excess levels of nitrite ion in drinking water interact with amine functionalized compounds to form carcinogenic nitrosamines, which cause stomach cancer. Thus, it is indispensable to develop a simple protocol to detect nitrite. In this paper, a Cu-metal-organic framework (Cu-MOF) with graphene oxide (GO) composite was synthesized by ultrasonication followed by solvothermal method and then fabricated on a glassy carbon (GC) electrode for the sensitive and selective determination of nitrite contamination. The SEM image of the synthesized Cu-MOF showed colloidosome-like structure with an average size of 8 μm. Interestingly, the Cu-MOF-GO composite synthesized by ultrasonic irradiation followed by solvothermal process produce controlled size of 3 μm colloidosome-like structure. This was attributed to the formation of an exfoliated sheet-like structure of GO by ultrasonication in addition to the obvious influence of GO providing the oxygen functional groups as a nucleation node for size-controlled growth. On the other hand, the composite prepared without ultrasonication exhibited 6.6 μm size agglomerated colloidosome-like structures, indicating the crucial role of ultrasonication for the formation of size-controlled composites. XPS results confirmed the presence of Cu(II) in the as-synthesized Cu-MOF-GO based on the binding energies at 935.5 eV for Cu 2p3/2 and 955.4 eV for Cu 2p1/2. The electrochemical impedance studies in [Fe(CN)6]3-/4- redox couple at the composite fabricated electrode exhibited more facile electron transfer than that with Cu-MOF and GO modified electrodes, which helped to utilize Cu-MOF-GO for trace level determination of nitrite in environmental effluent samples. The Cu-MOF-GO fabricated electrode offered a superior sensitive platform for nitrite determination than the Cu-MOF and GO modified electrodes demonstrating oxidation at less positive potential with enhanced oxidation current. The present sensor detects nitrite in the concentration range of 1 × 10-8 to 1 × 10-4 M with the lowest limit of detection (LOD) of 1.47 nM (S/N = 3). Finally, the present Cu-MOF-GO electrode was successfully exploited for nitrite ion determination in lake and dye contaminated water samples.
    Matched MeSH terms: Oxygen
  17. Jamain Z, Khairuddean M, Guan-Seng T
    Int J Mol Sci, 2020 Jun 16;21(12).
    PMID: 32560033 DOI: 10.3390/ijms21124267
    Two series of new hexasubstituted cyclotriphosphazene derivatives were successfully synthesized and characterized. These derivatives are differentiated by two types of linking units in the molecules such as amide-azo (6a-j) and azo-azo (8a-j). The homologues of the same series contain different terminal substituents such as heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxyl, carboxyl, chloro, nitro, and amino groups. All the intermediates and final compounds were characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), and Carbon, Hydrogen, and Nitrogen (CHN) elemental analysis. Liquid crystal properties for all compounds were determined using polarized optical microscope (POM). It was found that only intermediates 2a-e with nitro and alkoxyl terminal chains showed a smectic A phase. All the final compounds with alkoxyl substituents are mesogenic with either smectic A or C phases. However, other intermediates and compounds were found to be non-mesogenic. The study on the fire retardancy of final compounds was determined using limiting oxygen index (LOI) method. The LOI value of pure polyester resin (22.53%) was increased up to 24.71% after treating with 1 wt% of hexachlorocyclotriphosphazene (HCCP). Moreover, all the compounds gave positive results on the LOI values and compound 6i with the nitro terminal substituent showed the highest LOI value of 27.54%.
    Matched MeSH terms: Oxygen
  18. Hossain MB, Habib SB, Hossain MS, Jolly YN, Kamal AHM, Idris MH, et al.
    Data Brief, 2020 Aug;31:105911.
    PMID: 32637507 DOI: 10.1016/j.dib.2020.105911
    Meghna River Estuary, the largest estuarine system (GBM, Ganges-Brahmaputra-Meghna) in Bangladesh, is a major spawning ground of national fish, Hilsha shad. In this study, we collected 24 surface sediment and 24 water samples from the entire lower estuary (4 sites, 3 sampling points from each site, 2 replicas from each sampling point) to detect trace/heavy metals. Sediment samples were collected from the top surface soil (0-5 cm) using Ekman grab sampler and water samples from 5 cm below the surface layer using plastic water bottles. After collection, sediment and water samples were preserved as necessary using HNO3 (for water). Immediately after reaching the laboratory, sediment samples were dried in an oven at 70°C until the constant weight gained. The metals were then analyzed using energy-dispersive X-ray fluorescence method (EDXRF) and calculated the metal concentrations. In total, 12 metals were detected and the average value (mg/Kg) of all metals for sediment samples followed the descending order of Fe > Ca > K >Ti >Sr >Zr >Rb> Cu > Zn >Pb >As > Ni, and for water the order (µg/mL) of Fe >Ti > Ca > Co >Mn > Ni > Zn >Sr > Cu > As > Se . Besides, several physicochemical parameters i.e. water pH, soil pH, temperature, salinity, dissolved oxygen, hardness, and alkalinity of the 12 sampling points were also measured in-situ using handheld instruments.
    Matched MeSH terms: Oxygen
  19. Zainudin Nh M, R A, W N R
    J Biomed Phys Eng, 2020 Jun;10(3):319-328.
    PMID: 32637376 DOI: 10.31661/jbpe.v0i0.1135
    Background: Radiation induced bystander effects (RIBEs) occurs in unirradiated cells exhibiting indirect biological effect as a consequence of signals from other irradiated cells in the population.

    Objective: In this study, bystander effects in MCF-7 breast cancer cells and hFOB 1.19 normal osteoblast cells irradiated with gamma emitting HDR Brachytherapy Ir-192 source were investigated.

    Material and Methods: In this in-vitro study, bystander effect stimulation was conducted using medium transfer technique of irradiated cells to the non-irradiated bystander cells. Cell viability, reactive oxygen species (ROS) generation and colony forming assay was employed to evaluate the effect.

    Results: Results indicate that the exposure to the medium irradiated MCF-7 induced significant bystander killing and decreased the survival fraction of bystander MCF-7 and hFOB from 1.19 to 81.70 % and 65.44 %, respectively. A significant decrease in survival fraction was observed for hFOB 1.19 bystander cells (p < 0.05). We found that the rate of hFOB 1.19 cell growth significantly decreases to 85.5% when added with media from irradiated cells. The ROS levels of bystander cells for both cell lines were observed to have an increase even after 4 h of treatment. Our results suggest the presence of bystander effects in unirradiated cells exposed to the irradiated medium.

    Conclusion: These data provide evidence that irradiated MCF-7 breast cancer cells can induce bystander death in unirradiated MCF-7 and hFOB 1.19 bystander cells. Increase in cell death could also be mediated by the ROS generation during the irradiation with HDR brachytherapy.

    Matched MeSH terms: Reactive Oxygen Species
  20. Balasubramaniam V, June Chelyn L, Vimala S, Mohd Fairulnizal MN, Brownlee IA, Amin I
    Heliyon, 2020 Aug;6(8):e04654.
    PMID: 32817893 DOI: 10.1016/j.heliyon.2020.e04654
    Three species of Malaysian edible seaweed (Eucheuma denticulatum, Sargassum polycystum and Caulerpa lentillifera) were analyzed for their carotenoid composition using a combination of high-performance thin layer chromatography (HPTLC) and ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS), while the antioxidant capacities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. The HPTLC analysis exhibited a distinct carotenoid pattern among the three seaweed groups. The UHPLC-ESI-MS/MS analysis showed fucoxanthin as the major carotenoid present in S. polycystum while lutein and zeaxanthin in E. denticulatum. For C. lentillifera, β-carotene and canthaxanthin were the major carotenoids. Some of the carotenoids, such as rubixanthin, dinoxanthin, diatoxanthin and antheraxanthin, were also tentatively detected in E. denticulatum and S. polycystum. For antioxidant activity, S. polycystum (20 %) and E. denticulatum (1128 μmol TE/g) showed the highest activity in the DPPH and ORAC assays, respectively. The findings suggest the three edible varieties of seaweeds may provide a good dietary source with a potential to reduce antioxidative stress.
    Matched MeSH terms: Oxygen Radical Absorbance Capacity
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