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Synthesis of novel benzohydrazone-oxadiazole hybrids as β-glucuronidase inhibitors and molecular modeling studies

Taha M, Ismail NH, Imran S, Selvaraj M, Rahim A, Ali M, et al.

Bioorg Med Chem, 2015 Dec 1;23(23):7394-404.
PMID: 26526743 DOI: 10.1016/j.bmc.2015.10.037

A series of compounds consisting of 25 novel oxadiazole-benzohydrazone hybrids (6-30) were synthesized through a five-step reaction sequence and evaluated for their β-glucuronidase inhibitory potential. The IC50 values of compounds 6-30 were found to be in the range of 7.14-44.16μM. Compounds 6, 7, 8, 9, 11, 13, 18, and 25 were found to be more potent than d-saccharic acid 1,4-lactone (48.4±1.25μM). These compounds were further subjected for molecular docking studies to confirm the binding mode towards human β-d-glucuronidase active site. Docking study for compound 13 (IC50=7.14±0.30μM) revealed that it adopts a binding mode that fits within the entire pocket of the binding site of β-d-glucuronidase. Compound 13 has the maximum number of hydrogens bonded to the residues of the active site as compared to the other compounds, that is, the ortho-hydroxyl group forms hydrogen bond with carboxyl side chain of Asp207 (2.1Å) and with hydroxyl group of Tyr508 (2.6Å). The other hydroxyl group forms hydrogen bond with His385 side chain (2.8Å), side chain carboxyl oxygen of Glu540 (2.2Å) and Asn450 side-chain's carboxamide NH (2.1Å).

Matched MeSH terms: Oxygen
Electrocoagulation using a rotated anode: A novel reactor design for textile wastewater treatment

Naje AS, Chelliapan S, Zakaria Z, Abbas SA

J Environ Manage, 2016 Jul 1;176:34-44.
PMID: 27039362 DOI: 10.1016/j.jenvman.2016.03.034

This paper investigates the optimum operational conditions of a novel rotated bed electrocoagulation (EC) reactor for the treatment of textile wastewater. The effect of various operational parameters such as rotational speed, current density (CD), operational time (RT), pH, temperature, and inter-electrode distance (IED) on the pollutant removal efficiency were examined. In addition, the consumption of aluminum (Al) and electrical energy, as well as operating costs at optimum conditions were also calculated. The results indicated that the optimum conditions for the treatment of textile wastewater were achieved at CD = 4 mA/cm(2), RT = 10 min, rotational speed = 150 rpm, pH = 4.57, temperature = 25 °C, and IED = 1 cm. The electrode consumption, energy consumption, and operating costs were 0.038 kg/m(3), 4.66 kWh/m(3) and 0.44 US$/m(3), respectively. The removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), turbidity and color were 97.10%, 95.55%, 98%, 96% and 98.50%, respectively, at the first 10 min of reaction time, while the phenol compound of the wastewater was almost entirely removed (99.99%). The experimental results confirm that the new reactor design with rotated anode impellers and cathode rings provided high treatment efficiency at a reduced reaction time and with lower energy consumption.

Matched MeSH terms: Biological Oxygen Demand Analysis
Fulltext Effects of glucose, ethanol and acetic acid on regulation of ADH2 gene from Lachancea fermentati

Yaacob N, Mohamad Ali MS, Salleh AB, Abdul Rahman NA

PeerJ, 2016;4:e1751.
PMID: 26989608 DOI: 10.7717/peerj.1751

Background. Not all yeast alcohol dehydrogenase 2 (ADH2) are repressed by glucose, as reported in Saccharomyces cerevisiae. Pichia stipitis ADH2 is regulated by oxygen instead of glucose, whereas Kluyveromyces marxianus ADH2 is regulated by neither glucose nor ethanol. For this reason, ADH2 regulation of yeasts may be species dependent, leading to a different type of expression and fermentation efficiency. Lachancea fermentati is a highly efficient ethanol producer, fast-growing cells and adapted to fermentation-related stresses such as ethanol and organic acid, but the metabolic information regarding the regulation of glucose and ethanol production is still lacking. Methods. Our investigation started with the stimulation of ADH2 activity from S. cerevisiae and L. fermentati by glucose and ethanol induction in a glucose-repressed medium. The study also embarked on the retrospective analysis of ADH2 genomic and protein level through direct sequencing and sites identification. Based on the sequence generated, we demonstrated ADH2 gene expression highlighting the conserved NAD(P)-binding domain in the context of glucose fermentation and ethanol production. Results. An increase of ADH2 activity was observed in starved L. fermentati (LfeADH2) and S. cerevisiae (SceADH2) in response to 2% (w/v) glucose induction. These suggest that in the presence of glucose, ADH2 activity was activated instead of being repressed. An induction of 0.5% (v/v) ethanol also increased LfeADH2 activity, promoting ethanol resistance, whereas accumulating acetic acid at a later stage of fermentation stimulated ADH2 activity and enhanced glucose consumption rates. The lack in upper stream activating sequence (UAS) and TATA elements hindered the possibility of Adr1 binding to LfeADH2. Transcription factors such as SP1 and RAP1 observed in LfeADH2 sequence have been implicated in the regulation of many genes including ADH2. In glucose fermentation, L. fermentati exhibited a bell-shaped ADH2 expression, showing the highest expression when glucose was depleted and ethanol-acetic acid was increased. Meanwhile, S. cerevisiae showed a constitutive ADH2 expression throughout the fermentation process. Discussion. ADH2 expression in L. fermentati may be subjected to changes in the presence of non-fermentative carbon source. The nucleotide sequence showed that ADH2 transcription could be influenced by other transcription genes of glycolysis oriented due to the lack of specific activation sites for Adr1. Our study suggests that if Adr1 is not capable of promoting LfeADH2 activation, the transcription can be controlled by Rap1 and Sp1 due to their inherent roles. Therefore in future, it is interesting to observe ADH2 gene being highly regulated by these potential transcription factors and functioned as a promoter for yeast under high volume of ethanol and organic acids.

Matched MeSH terms: Oxygen
Fulltext Novel chemical synthesis and characterization of copper pyrovanadate nanoparticles and its influence on the flame retardancy of polymeric nanocomposites

Ghiyasiyan-Arani M, Masjedi-Arani M, Ghanbari D, Bagheri S, Salavati-Niasari M

Sci Rep, 2016 05 04;6:25231.
PMID: 27143312 DOI: 10.1038/srep25231

In this work, copper pyrovanadate (Cu3V2O7(OH)2(H2O)2) nanoparticles have been synthesized by a simple and rapid chemical precipitation method. Different copper-organic complexes were used to control the size and morphology of products. The morphology and structure of the as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectrum, electron dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA), differential thermal analysis (DTA) and photoluminescence (PL) spectroscopy. The influence of copper pyrovanadate nanostructures on the flame retardancy of the polystyrene, poly vinyl alcohol and cellulose acetate was studied. Dispersed nanoparticles play the role of a magnetic barrier layer, which slows down product volatilization and prevents the flame and oxygen from the sample during decomposition of the polymer. Cu3V2O7(OH)2(H2O)2 is converted to Cu3V2O8 with an endothermic reaction which simultaneously releases water and decrease the temperature of the flame region.

Matched MeSH terms: Oxygen
Polishing of treated palm oil mill effluent (POME) from ponding system by electrocoagulation process

Bashir MJ, Mau Han T, Jun Wei L, Choon Aun N, Abu Amr SS

Water Sci Technol, 2016;73(11):2704-12.
PMID: 27232407 DOI: 10.2166/wst.2016.123

As the ponding system used to treat palm oil mill effluent (POME) frequently fails to satisfy the discharge standard in Malaysia, the present study aimed to resolve this problem using an optimized electrocoagulation process. Thus, a central composite design (CCD) module in response surface methodology was employed to optimize the interactions of process variables, namely current density, contact time and initial pH targeted on maximum removal of chemical oxygen demand (COD), colour and turbidity with satisfactory pH of discharge POME. The batch study was initially designed by CCD and statistical models of responses were subsequently derived to indicate the significant terms of interactive process variables. All models were verified by analysis of variance showing model significances with Prob > F < 0.01. The optimum performance was obtained at the current density of 56 mA/cm(2), contact time of 65 min and initial pH of 4.5, rendering complete removal of colour and turbidity with COD removal of 75.4%. The pH of post-treated POME of 7.6 was achieved, which is suitable for direct discharge. These predicted outputs were subsequently confirmed by insignificant standard deviation readings between predicted and actual values. This optimum condition also permitted the simultaneous removal of NH3-N, and various metal ions, signifying the superiority of the electrocoagulation process optimized by CCD.

Matched MeSH terms: Biological Oxygen Demand Analysis
Removal Rate of Organic Matter Using Natural Cellulose via Adsorption Isotherm and Kinetic Studies

Din MF, Ponraj M, Low WP, Fulazzaky MA, Iwao K, Songip AR, et al.

Water Environ Res, 2016 Feb;88(2):118-30.
PMID: 26803100 DOI: 10.2175/106143015X14362865227913

In this study, the removal of natural organic matter (NOM) using coconut fiber (CF) and palm oil fiber (POF) was investigated. Preliminary analysis was performed using a jar test for the selection of optimal medium before the fabricated column model experiment. The equilibrium studies on isotherms and kinetic models for NOM adsorption were analyzed using linearized correlation coefficient. Results showed that the equilibrium data were fitted to Langmuir isotherm model for both CF and POF. The most suitable adsorption model was the pseudo-first-order kinetic model for POF and pseudo-second-order kinetic model for CF. The adsorption capacities achieved by the CF and POF were 15.67 and 30.8 mg/g respectively. Based on this investigation, it can be concluded that the POF is the most suitable material for the removal of NOM in semi polluted river water.

Matched MeSH terms: Biological Oxygen Demand Analysis
Fulltext Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor

Wang J, Mahmood Q, Qiu JP, Li YS, Chang YS, Li XD

Biomed Res Int, 2015;2015:398028.
PMID: 26167485 DOI: 10.1155/2015/398028

Large volumes of untreated palm oil mill effluent (POME) pose threat to aquatic environment due to the presence of very high organic content. The present investigation involved two pilot-scale anaerobic expanded granular sludge bed (EGSB) reactors, continuously operated for 1 year to treat POME. Setting HRT at 9.8 d, the anaerobic EGSB reactors reduced COD from 71179 mg/L to 12341 mg/L and recycled half of sludge by a dissolved air flotation (DAF). The average effluent COD was 3587 mg/L with the consistent COD removal efficiency of 94.89%. Adding cationic polymer (PAM) dose of 30 mg/L to DAF unit and recycling its half of sludge caused granulation of anaerobic sludge. Bacilli and small coccid bacteria were the dominant microbial species of the reactor. The reactor produced 27.65 m(3) of biogas per m(3) of POME which was utilized for electricity generation.

Matched MeSH terms: Biological Oxygen Demand Analysis
Oxidised low density lipoprotein causes human macrophage cell death through oxidant generation and inhibition of key catabolic enzymes

Katouah H, Chen A, Othman I, Gieseg SP

Int J Biochem Cell Biol, 2015 Oct;67:34-42.
PMID: 26255116 DOI: 10.1016/j.biocel.2015.08.001

Oxidised low density lipoprotein (oxLDL) is thought to be a significant contributor to the death of macrophage cells observed in advanced atherosclerotic plaques. Using human-derived U937 cells we have examined the effect of cytotoxic oxLDL on oxidative stress and cellular catabolism. Within 3h of the addition of oxLDL, there was a rapid, concentration dependent rise in cellular reactive oxygen species followed by the loss of cellular GSH, and the enzyme activity of both glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and aconitase. The loss of these catabolic enzymes was accompanied by the loss of cellular ATP and lower lactate generation. Addition of the macrophage antioxidant 7,8-dihydroneopterin inhibited the ROS generation, glutathione loss and catabolic inactivation. NOX was shown to be activated by oxLDL addition while apocynin inhibited the loss of GSH and cell viability. The data suggests that oxLDL triggers an excess of ROS production through NOX activation, and catabolic failure through thiol oxidation resulting in cell death.

Matched MeSH terms: Reactive Oxygen Species/antagonists & inhibitors; Reactive Oxygen Species/metabolism*; Reactive Oxygen Species/agonists
Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule

Soh EY, Chhabra SR, Halliday N, Heeb S, Müller C, Birmes FS, et al.

Environ Microbiol, 2015 Nov;17(11):4352-65.
PMID: 25809238 DOI: 10.1111/1462-2920.12857

In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline-3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4-diones, but was unable to inactivate the PQS precursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.

Matched MeSH terms: Oxygen
The effect of aeration and non-aeration time on simultaneous organic, nitrogen and phosphorus removal using an intermittent aeration membrane bioreactor

Ujang Z, Salim MR, Khor SL

Water Sci Technol, 2002;46(9):193-200.
PMID: 12448469

A laboratory-scale membrane bioreactor (MBR) was fed with synthetic wastewater to investigate the possibility of simultaneous removal of organic, nitrogen and phosphorus by intermittent aeration. The MBR consists of two compartments using a microfiltration membrane with 0.2 microm pore size and a surface area of 0.35 m2. Hydraulic retention time was set at 24 hours and solid retention time 25 days. MLSS concentration in the reactor was in the range of 2,500-3,800 mg/L. The MLSS internal recycling ratio was maintained at 100% influent flow rate. Intermittent aeration was applied in this study to provide an aerobic-anaerobic cycle. Three stages of operations were conducted to investigate the effect of aeration and non-aeration on simultaneous organic and nutrient removal. In Stage 1, time cycles of aeration and non-aeration were set at 90/150 min and 150/90 min in the first and second compartment, the removal efficiency was 97%, 94% and 70% for COD, nitrogen and phosphorus respectively. In Stage 2, time cycles of aeration and non-aeration were set at 60/120 min and 120/60 min in the first and second compartment, the removal efficiency was 97%, 96% and 71% for COD, nitrogen and phosphorus respectively. In Stage 3, time cycles of aeration and non-aeration were set at 120/120 min and 120/120 min in compartment 1 and 2, the removal efficiency was 98%, 96% and 78% for COD, nitrogen and phosphorus respectively. Results show that longer non-aeration time in the second compartment provided better performances of biological phosphorus removal.

Matched MeSH terms: Oxygen
Termite assemblages, forest disturbance and greenhouse gas fluxes in Sabah, East Malaysia

Eggleton P, Homathevi R, Jones DT, MacDonald JA, Jeeva D, Bignell DE, et al.

Philos Trans R Soc Lond B Biol Sci, 1999 Nov 29;354(1391):1791-802.
PMID: 11605622

A synthesis is presented of sampling work conducted under a UK government-funded Darwin Initiative grant undertaken predominantly within the Danum Valley Conservation Area (DVCA), Sabah, East Malaysia. The project concerned the assemblage structure, gas physiology and landscape gas fluxes of termites in pristine and two ages of secondary, dipterocarp forest. The DVCA termite fauna is typical of the Sunda region, dominated by Termes-group soil-feeders and Nasutitermitinae. Selective logging appears to have relatively little effect on termite assemblages, although soil-feeding termites may be moderately affected by this level of disturbance. Species composition changes, but to a small extent when considered against the background level of compositional differences within the Sunda region. Physiologically the assemblage is very like others that have been studied, although there are some species that do not fit on the expected body size-metabolic rate curve. As elsewhere, soil-feeders and soil-wood interface-feeders tend to produce more methane. As with the termite assemblage characteristics, gross gas and energy fluxes do not differ significantly between logged and unlogged sites. Although gross methane fluxes are high, all the soils at DVCA were methane sinks, suggesting that methane oxidation by methanotrophic bacteria was a more important process than methane production by gut archaea. This implies that methane production by termites in South-East Asia is not contributing significantly to the observed increase in levels of methane production worldwide. Biomass density, species richness, clade complement and energy flow were much lower at DVCA than at a directly comparable site in southern Cameroon. This is probably due to the different biogeographical histories of the areas.

Matched MeSH terms: Oxygen Consumption
Dinoflagellate bloom in tropical fish ponds of coastal waters of the South China Sea

Shamsudin L, Awang A, Ambak A, Ibrahim S

Environ Monit Assess, 1996 May;40(3):303-11.
PMID: 24198160 DOI: 10.1007/BF00398875

Red tide of dinoflagellate was observed in brackish water fish ponds of Terengganu along the coast of the South China Sea during the study period between January 1992 to December 1992. The nearby coastal moat water facing the South China Sea is the source of water for fish pond culture activities of sea bass during the study period. An examination of water quality in fish ponds during the study period indicated that both the organic nutrients were high during the pre-wet monsoon period. The source of the nutrients in coastal water was believed to be derived from the agro-based industrial effluents, fertilizers from paddy fields and untreated animal wastes. This coincided with the peak production of dinoflagellate in the water column in October 1992. The cell count ranges from 8.3 to 60.4×10.4×10(4)/l during the bloom peak period and the bloom species were compared entirely of non-toxic dinoflagellates with Protoperidinium quinquecorne occurring >90% of the total cell count. However, both cultured and indigenous fish species were seen to suffer from oxygen asphyxiation (suffocation due to lack of oxygen). The bloom lasted for a short period (4-5 days) with a massive cell collapse from subsurface to bottom water on the sixth day. The productivity values ranged from 5-25 C g/ l / h with a subsurface maximum value in October 1992. Two species of Ciliophora, Tintinnopsis and Favella, were observed to graze on these dinoflagellates at the end of the bloom period.

Matched MeSH terms: Oxygen
Physical and physiological profiles of Malaysian dragon boat rowers

Singh R, Singh HJ, Sirisinghe RG

Br J Sports Med, 1995 Mar;29(1):13-5.
PMID: 7788209

Maximal oxygen consumption (VO2max) and maximal workload attained (WLmax) were determined in 28 Malaysian dragon boat rowers who were exercised to exhaustion on an arm ergometer. Mean VO2max was 2.75 l min-1 at a mean WLmax of 195.5 W. Anaerobic endurance power of the arms, determined by cranking at 100 RPM at a workload of 400 W and the time taken to maintain the cadence until it fell to 75 RPM, was 34.9(+/- 2.3) s. Leg performance, as determined by standing long jump and vertical jump, was 140.0(+/- 4.5) kg m and 100.3(+/- 3.1) kg m s-1 respectively. Right hand grip strength was significantly (p < 0.001) greater than the left hand. Percentage body fat of the rowers was 11.8(+/- 0.6)%. These values represent the first measurements of their kind performed on dragon boat rowers in Malaysia.

Matched MeSH terms: Oxygen Consumption
A feasibility study for appraising recreational water quality in a Southeast Asian beach complex

Appan A

Environ Monit Assess, 1991 Oct;19(1-3):361-72.
PMID: 24233953 DOI: 10.1007/BF00401325

In a case study involving preliminary investigations for the feasibility of a beach resort complex in the west coast of Sarawak, Malaysia, since the acceptable quality of recreational water quality had not been specified, existing international standards and practices were reviewed to arrive at acceptable microbiological and physicochemical parametric levels. Water samples were collected on a weekly basis in the proposed beach complex at Tanjong Batu Coastal Reserve and also along the nearby Sungei Batang Kemena and its estuary. It was ascertained that the swimming water quality was acceptable in terms of faecal Coliforms, temperature, pH and dissolved oxygen. However E. Coli counts did indicate a potential risk of 1.68% for gastrointestinal illness and the ubiquitous presence of faecal Streptococci pointed to recent pollution of human or animal origin. Besides, grease and oil contents exceeded the WHO Guideline values. It was hence recommended that an appropriate sanitation or pollution survey should be carried out in the adjacent coastal catchment area and the beach. Also routine water sampling should be undertaken. Such action will help to pinpoint sources of pollution and lead to antipollution measures, thus helping to upgrade swimming water quality and establish swimming water quality standards.

Matched MeSH terms: Oxygen
Fulltext A comparative study of aerobic capacity – VO2 max between common ethnic populations of Sabah, Malaysia

Nagesh Chodankar N., Vinoth Kumar, Urban John Arnold D’Souza, Ahmad Faris Abdullah

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):47-47.
MyJurnal

Introduction: Aerobic power reflects the physical fitness of the individual. Evidences support differences in phys-iological responses to exercise. There is less data on VO2 max among common ethnic population of Sabah. Ob-jective of this study was to investigate VO2 max among Kadazan, Dusun, Brunei Melayu, Bugis, Murut and others of Sabah in male and female young adult population. Methods: A total of 385 participants were randomly selected. Monark 894 E leg bicycle ergo meter was used to measure aerobic power VO2 max. Based on the heart rate male and female respectively 450 & 300 kilogram-force meter/minute was chosen. Based on Astrand rhyming nomogram (age correction factor included-VO2 Max multiplied by 1.05) calculations Vo2Max was calculated in l/min. The age correction done VO2 Max (l/min) was multiplied by 1000 and later divided by the body weight to derive the actual VO2Max in ml/kg/min. The recovery heart rate after 1 minute was taken and the difference were calculated for the further analysis. Data was tabulated and analysed by one way ANOVA test - Hocherberg’s GT2. Results: There was no significant difference in VO2 max between the common ethnic young adult population both in males and fe-males. Conclusion: There is no significant difference in VO2 max among the common ethnic adult but have a similar aerobic capacity in the study group.

Matched MeSH terms: Oxygen Consumption
Fulltext Charaterization of mosquito larval habitats in Qatar

Alkhayat FA, Ahmad AH, Rahim J, Dieng H, Ismail BA, Imran M, et al.

Saudi J Biol Sci, 2020 Sep;27(9):2358-2365.
PMID: 32884417 DOI: 10.1016/j.sjbs.2020.07.006

Mosquito borne diseases have remained a grave threat to human health and are posing a significant burden on health authorities around the globe. The understanding and insight of mosquito breeding habitats features is crucial for their effective management. Comprehensive larval surveys were carried out at 14 sites in Qatar. A total of 443 aquatic habitats were examined, among these 130 were found positive with Culex pipiens, Cx. quinquefasciatus, Cx. mattinglyi, Ochlerotatus dorsalis, Oc. caspius and Anopheles stephensi. The majority of positive breeding habitats were recorded in urban areas (67.6%), followed by livestock (13.8%), and least were in agriculture (10.7%). An. stephensi larvae were positively correlated with Cx. pipien, Cx. quinquefasciatus, and negatively with water salinity. Large and shaded habitats were the most preferred by An. stephensi. In addition, Cx. pipiens was positively associated with the turbidity and pH, and was negatively associated with vegetation and habitat size. A negative association of Cx. quinquefasciatus with dissolved oxygen, water temperature, and salinity, while positive with habitat surface area was observed. Oc. dorsalis was negatively correlated with pH, water temperature, depth, and habitat surface area, whereas salinity water was more preferable site for females to lay their eggs. These results demonstrate that environmental factors play a significant role in preference of both anopheline and culicine for oviposition, while their effective management must be developed as the most viable tool to minimize mosquito borne diseases.

Matched MeSH terms: Oxygen
Fulltext Graphene/PVA buckypaper for strain sensing application

Mehmood A, Mubarak NM, Khalid M, Jagadish P, Walvekar R, Abdullah EC

Sci Rep, 2020 11 18;10(1):20106.
PMID: 33208815 DOI: 10.1038/s41598-020-77139-2

Strain sensors in the form of buckypaper (BP) infiltrated with various polymers are considered a viable option for strain sensor applications such as structural health monitoring and human motion detection. Graphene has outstanding properties in terms of strength, heat and current conduction, optics, and many more. However, graphene in the form of BP has not been considered earlier for strain sensing applications. In this work, graphene-based BP infiltrated with polyvinyl alcohol (PVA) was synthesized by vacuum filtration technique and polymer intercalation. First, Graphene oxide (GO) was prepared via treatment with sulphuric acid and nitric acid. Whereas, to obtain high-quality BP, GO was sonicated in ethanol for 20 min with sonication intensity of 60%. FTIR studies confirmed the oxygenated groups on the surface of GO while the dispersion characteristics were validated using zeta potential analysis. The nanocomposite was synthesized by varying BP and PVA concentrations. Mechanical and electrical properties were measured using a computerized tensile testing machine, two probe method, and hall effect, respectively. The electrical conducting properties of the nanocomposites decreased with increasing PVA content; likewise, electron mobility also decreased while electrical resistance increased. The optimization study reports the highest mechanical properties such as tensile strength, Young's Modulus, and elongation at break of 200.55 MPa, 6.59 GPa, and 6.79%, respectively. Finally, electrochemical testing in a strain range of ε ~ 4% also testifies superior strain sensing properties of 60 wt% graphene BP/PVA with a demonstration of repeatability, accuracy, and preciseness for five loading and unloading cycles with a gauge factor of 1.33. Thus, results prove the usefulness of the nanocomposite for commercial and industrial applications.

Matched MeSH terms: Oxygen
The Value of Oxygen Desaturation Index for Diagnosing Obstructive Sleep Apnea: A Systematic Review

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
Fulltext Synthesis, characterization and application of gelatin-carboxymethyl cellulose blend films for preservation of cherry tomatoes and grapes

Samsi MS, Kamari A, Din SM, Lazar G

J Food Sci Technol, 2019 Jun;56(6):3099-3108.
PMID: 31205364 DOI: 10.1007/s13197-019-03809-3

In the present study, gelatin-carboxymethyl cellulose blend film was synthesized, characterized and applied for the first time to preserve cherry tomatoes (Solanum lycopersicum var. cerasiforme) and grapes (Vitis vinifera). Gelatin (Gel) film forming solution was incorporated with carboxymethyl cellulose (CMC) at three volume per volume (Gel:CMC) ratios, namely 75:25, 50:50 and 25:75. CMC treatment has improved the transparency, tensile strength (TS), elongation at break (EAB), water vapor permeability and oxygen permeability of gelatin films. A pronounced effect was obtained for 25Gel:75CMC film. The TS and EAB values were increased from 25.98 MPa and 2.34% (100Gel:0CMC) to 37.54 MPa and 4.41% (25Gel:75CMC), respectively. A significant improvement in antimicrobial property of gelatin films against two food pathogens, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was obtained in the presence of CMC. The effectiveness of gelatin-CMC blend films to extend the shelf life of agricultural products was evaluated in a 14-day preservation study. The gelatin-CMC films were successfully controlled the weight loss and browning index of the fruits up to 50.41% and 31.34%, respectively. Overall, gelatin-CMC film is an environmental friendly film for food preservation.

Matched MeSH terms: Oxygen
Effects of environmental conditions and nutrients on the occurrence and distribution of potentially harmful phytoplankton in mesotrophic water

Soon TK, Julian Ransangan

Sains Malaysiana, 2016;45:865-877.

Marudu Bay, north coast of Sabah is characterized with mesotrophic water body and typical environmental parameters
throughout the year. The current study was undertaken to evaluate the effect of environmental parameters and nutrients
in mesotrophic water on the occurrence and distribution of potentially harmful phytoplankton species. The samplings
were conducted over a period of thirteen months, covering southwest monsoon (SWM), inter-monsoon (IM), and northeast
monsoon (NEM), at ten stations throughout the bay. Physical parameters (temperature, salinity, pH, dissolved oxygen,
current speed and secchi depth), biological parameters (cell densities of phytoplankton) and chemical parameters
(phosphate, nitrate, silicate and ammonia) were examined. The results indicated at least eight potentially harmful
phytoplankton species (Dinophysis caudata, D. miles, Ceratium furca, C. fursus, Prorocentrum micans, P. sigmoides, P.
triestinum and Pseudo-nitzschia sp.) were detected in north coast of Sabah. However, the potentially harmful phytoplankton
species contributed only about 1.3% of the total phytoplankton community. Under nutrient deprivation conditions, the
potentially harmful phytoplankton species distribution was mainly influenced by the ability to utilize other nitrogen
sources, cell mobility and toleration to low nutrients environments.

Matched MeSH terms: Oxygen

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