Dissolved Oxygen Meter Research Articles

Determination of saturated dissolved oxygen concentration in iron sulfate solutions containing iron oxidizing microorganisms

Iron sulfate solutions and the extremophile lifeforms that can live within them are industrially and environmentally important in many applications and require proper assessments of solution properties. Determination of saturated dissolved oxygen concentration is an important parameter for monitoring iron biooxidation processes. However, its determination is not so straight forward using commercially available dissolved oxygen meters. Such meters utilize internal calculation models based on the saline properties of seawater which can be easily overlooked. A method for determination of the saturated dissolved oxygen concentration in acidic iron sulfate solutions with the inclusion of other inorganic salts is proposed in this work using the biooxidation of ferrous iron as an indicator measured with redox potential and converted to oxygen concentration through bioreaction stoichiometry. The technique was tested on a BioGenerator system over the course of four days and proved satisfactory in establishing a value for the saturated dissolved oxygen concentration of the bioreactor broth. Study of the lifespan properties of the microorganisms in absence of ferrous iron substrate was briefly examined to determine the effective handling period of solutions for assessment.

Appraisal on heavy metal contamination in tissues (gills, intestine, liver, and fillet) of <i>Parachanna obscura</i> and the physicochemical properties of Oguta Lake, South-Eastern Nigeria.

The aim of this study is to provide baseline data on the investigation of concentrations of copper (Cu), lead (Pb), iron (Fe), manganese (Mn), and zinc (Zn) in various tissues (gills, intestine, liver, and fillet) of Parachanna obscura in Oguta Lake, and to assess physicochemical properties of Oguta lake to determine level of pollution and contamination. Twenty fish samples in total were collected at the fishermen landing site of the lake and analyzed using the Atomic Absorption Spectroscopy (AAS). Dissolved oxygen and temperature were measured on site using dissolved Oxygen meter (model 5509) and Mercury-in-glass thermometer respectively, while other parameters were analyzed in the laboratory. Results indicated Fe had the highest concentrations (1.479±0.003 mg/kg) especially in the gills, while Mn recorded least concentrations (0.001±0.000) mg/kg) of all metals analyzed. Values for Cu (0.026±0.002 mg/kg), Mn (0.001±0.000 mg/kg), Zn (.782±0.015 mg/kg), and Fe (1.479±0.030 mg/kg) levels were within FAO/WHO permissible limits in all tissues, whereas Pb (1.438±0.015 mg/kg) exceeded standard limits especially in the gills and intestines, indicating potential contamination and threats to aquatic and human health. Heavy metal concentrations in the tissues followed the order: gills > intestine > fillet > liver. The physicochemical properties assessment of Oguta Lake indicated a stable temperature with mean value of (28.02±022 C). The lake's temperature supports aquatic life, but challenges like low transparency (1.22±0.13 m), acidic pH levels (5.83±0.09), elevated ammonium levels (0.63±0.03 mg/l), low nitrate-nitrogen levels (0.0±50.00 mg/l), and fluctuating dissolved oxygen (6.50±0.29 mg/l) levels suggests pollution from agricultural runoff or sewage. The findings proffer effective management through pollution control, enhanced buffering capacity, and rigorous monitoring to safeguard biodiversity and ensure longterm ecological health.

Comparative Evaluation of Water Quality Properties: A Case Study of Coupled Commercial Aquaponics System

The current study intends to evaluate the influence of seasonal changes on the water quality parameters of a coupled commercial aquaponics system. The determined water quality parameters for the comparative study were total ammonium-nitrogen (TAN), nitrate-nitrogen (NO3-N) and phosphate (PO43-), water temperature (WT), water pH, dissolved oxygen (DO), electrical conductivity (EC), and total dissolved solids (TDS). The WT and DO analysis were carried out using a portable dissolved oxygen meter (Model: PDO-520, Taiwan). A portable electrode pH meter (Model: PH-220, Taiwan) was utilized for the pH measurement. The TDS and EC readings were obtained using a multi-parameter water quality meter (PHT-27, China). The TAN, NO3-N, and PO43- determinations were done using their individual Merck Spectro-quant® test kits. The research results indicated a significant (p0.05) difference. The observed significant increase of NO3-N, PO43-, EC, and TDS in the summer and autumn periods could be associated to the increased fish feeding rate (which increases waste production) as well as relative increase in microbial waste conversion/mineralization. The investigated water quality makers were within the recommended amounts in the aquaponics system. Thus, in this study, seasonal differences have induced variation in the NO3-N, PO43-, WT, pH, EC, and TDS amounts. However, these differences do not affect the TAN and DO levels.

SPATIO-TEMPORAL EVALUATION OF FERORO STREAM WATER QUALITY, CHIKUN LOCAL GOVERNMENT AREA OF KADUNA STATE, NIGERIA

Aquatic environment is faced with pollution problems most of which are anthropogenic in nature. Feroro stream water was evaluated for its quality and suitability for the growth of organisms. The temporal and spatial qualities of the water was observed to be deteriorating. Water sampling was done once monthly for twenty-four months from five stations along the stream. The water samples were put into 2-litre sterilized plastic bottles. Some physical and chemical parameters were determined using HANNA meter, Dissolved oxygen meter, titration and colorimeter methods. All the parameters tested ranged within Federal Ministry of Environment standard limits. Turbidity and Total Hardness are above the standard limits. There was significant difference temporally P<0.05. Electrical Conductivity was significant different in all the stations P<0.05, lowest at Station 1(137.55µS/cm) and high at Station 5 (235.21µS/cm). Across the wet and dry seasons, the parameters significantly varied except in Temperature (25.79±0.12 and 25.57±0.26) and Total Hardness (119.68±6.13 and 109.50±3.38) P<0.05.

DOxy: A Dissolved Oxygen Monitoring System.

Dissolved Oxygen (DO) in water enables marine life. Measuring the prevalence of DO in a body of water is an important part of sustainability efforts because low oxygen levels are a primary indicator of contamination and distress in bodies of water. Therefore, aquariums and aquaculture of all types are in need of near real-time dissolved oxygen monitoring and spend a lot of money on purchasing and maintaining DO meters that are either expensive, inefficient, or manually operated-in which case they also need to ensure that manual readings are taken frequently which is time consuming. Hence a cost-effective and sustainable automated Internet of Things (IoT) system for this task is necessary and long overdue. DOxy, is such an IoT system under research and development at Santa Clara University's Ethical, Pragmatic, and Intelligent Computing (EPIC) Laboratory which utilizes cost-effective, accessible, and sustainable Sensing Units (SUs) for measuring the dissolved oxygen levels present in bodies of water which send their readings to a web based cloud infrastructure for storage, analysis, and visualization. DOxy's SUs are equipped with a High-sensitivity Pulse Oximeter meant for measuring dissolved oxygen levels in human blood, not water. Hence a number of parallel readings of water samples were gathered by both the High-sensitivity Pulse Oximeter and a standard dissolved oxygen meter. Then, two approaches for relating the readings were investigated. In the first, various machine learning models were trained and tested to produce a dynamic mapping of sensor readings to actual DO values. In the second, curve-fitting models were used to produce a successful conversion formula usable in the DOxy SUs offline. Both proved successful in producing accurate results.

Determination of Henry's law coefficient of oxygen in LAB for JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) requires that the detector use liquid scintillator with an extremely low background to achieve the desired measurement accuracy of neutrino mixing parameters. In addition, the production process of the liquid scintillator must avoid radon gas contamination caused by equipment leakage. Direct measurement of radon gas in liquid scintillator is an option for system leak detection. However, considering the low percentage of radon gas and high percentage of oxygen in air, the measurement of oxygen in liquid scintillator will have higher sensitivity. Based on Henry's law and the measuring principle of a dissolved oxygen meter, an experimental device is designed to measure Henry's law coefficient and calibrate the dissolved oxygen meter. Henry's law coefficient of oxygen in linear alkylbenzene (LAB) at 23.6 °C derived from an experimental measurement is 2.09 × 107 ± 2.54 × 106 Pa·L·mol-1. The feasibility of using a dissolved oxygen meter to measure the dissolved oxygen content in LAB is verified by calibrating the dissolved oxygen meter.

Evaluation of rise in pH and oxygen release at the site of simulated external root resorption cavities using different oxygen-releasing biomaterials: An in vitro study.

External inflammatory root resorption has rapid onset and progresses aggressively. It leads to cementum loss, which allows communication between the infected pulp and the periodontium through the denuded dentinal tubules. Primary management strategy includes adequate chemomechanical debridement and lesion arrest for which maintaining alkaline pH and aerobic conditions is essential for healing and repair of the resorption defect. The aim of this study is to evaluate rise in pH and oxygen release at the site of simulated external root resorption cavities using different oxygen-releasing biomaterials. In 40 extracted single-rooted teeth access opening and chemomechanical debridement were done. Cavities simulating resorption defect are prepared on the roots. The samples are divided into four groups (n = 10) based on the biomaterial used. After placing the biomaterial, the root apices were sealed. Half of the samples from each group were tested for oxygen release using dissolved oxygen meter and the other half for rise in pH using pH meter at 7, 14, 21, and 28 days. The pH values were analyzed using Friedman 2-way analysis of variance (ANOVA) and Kruskal-Wallis test. Oxygen release was measured using the two-way and repeated-measures ANOVA. Calcium peroxide group showed the highest mean pH and oxygen release than other groups at any given point of time. Incorporating oxygen-releasing biomaterials such as calcium peroxide and perfluorodecalin into intracanal medicaments, such as calcium hydroxide, creates an alkaline and oxygen-enriched milieu in the periapical tissues.

Physical and Chemical Scrutiny of Obizi River in Awka South Local Government Area of Anambra State, Nigeria for Domestic Consumption

The Obizi River in the Awka South Local Government Area of Anambra State was examined physically and chemically to evaluate its contamination level and suitability for home use. It is important for recreational, fishing, cooking, drinking, and other applications. Its typical applications for drinking, cooking, fishing, recreational activities and other uses are limited since it flows through a canal that might be contaminated by industrial, agricultural, and other human activities. Nitrate mg/l, nitrite mg/l, magnesium mg/l, zinc mg/l, total dissolved solid (TDS) mg/l, hardness mg/l, sulphate mg/l, phosphate mg/l, alkalinity mg/l, acidity mg/l, sodium mg/l, biological oxygen demand (BOD) mg/l, chemical oxygen demand (COD) mg/l, total suspended solid (TSS) mg/l, TS mg/l, oxygen demand (OD) mg/l, and potassium mg/l are among the parameters that were evaluated. Total dissolved solids (TSS) were calculated as the difference between total solids and total dissolved solids. The zinc and nitrate elements within the samples were measured using the ultraviolet (UV) VIS spectrophotometric method. Sulphate was determined turbidimetrically by the absorption spectrophotometry. Magnesium content, total hardness, and alkalinity were measured through titration. TDS (mg/L) was measured with a Multi-Meter (HI 991300, Hanna Equipments, Romania), potassium and sodium ions were assessed by flame photometric technique, chemical oxygen demand (COD) was identified photometrically using the SpectroQuant Nova 60 COD cell test (Merck) in the range of 10 – 150 mg/L. Biological oxygen demand (BOD) was determined using the OxiDirect BOD system and total suspended solids (TSS) was calculated as the difference between total solids and total dissolved solids. Phosphates were measured using the ascorbic acid method, total solids were estimated gravimetrically, and oxygen demand (OD) was measured on-site using a dissolved oxygen meter JENWAY-3405 (Manufacturer: Barloworld Scientific Ltd., England). To find out if the results were significant or not, the parameters were subjected to an ANOVA single factor analysis. The analysis's conclusion was that the data were statistically not significant. Since nitrate and OD were above the World Health Organization's (WHO) limit while most other physicochemical parameters were below it, the ANOVA result showed that there was no significant difference between the physicochemical characteristics of the water samples. With the exception of nitrite and OD, which are above the WHO limit for domestic drinking water and other purposes, it was discovered that the majority of the physicochemical parameters fell within the organization's water quality standards for these purposes. As a result, the water quality is not good and should not be drunk unless treated.

Impact of Artisanal Crude Oil Refining Effluents on Interstitial Water at a Mangrove Wetland, Asari-Toru Axis of Sombreiro River, Rivers State.

A comparative study on the water quality of the interstitial water of two creeks in Rivers State was conducted. Temperature, pH, Conductivity, Dissolved oxygen, biochemical oxygen demand, Salinity, and Total dissolved solid were checked with an in-situ hand-held multi-meter (The EZODO Multi-meter). Dissolved oxygen (DO) was measured with a Milwaukee Dissolved oxygen meter while Biochemical Oxygen Demand (BOD) was determined by the 5-day BOD test (APHA, 2005). The temperature ranged between 28.3 to 29.3℃ in the Opro-ama creek and 26.0 -26.8℃ in Buguma creek. The pH value ranged from 6.2 to 6.8 in Opro-ama creek while that of Sa-ama creek was between 6.8 and 6.99. Salinity ranges from 9.1 to 9.5 (ppt) in the Opro-ama creek while Sa-ama creek recorded a range between 11.2 to 12.0 (ppt). The dissolved oxygen was between 1.5 and 2.3 (µS/cm) in Okpoka creek meanwhile Sa-ama creek varied between 4.6 and 4.10 (µS/cm). The biochemical oxygen demand values were between 1.4 to 2.3 (µS/cm) in Opro-ama creek while that of Sa-ama was between 1.9 to 2.4 (µS/cm). The conductivity values for the Opro-ama creek were between 10.3 and 10.6 while Sa-ama creek recorded a value of 12.5 to12.6 (µS/cm). there were significant variations (P

An In Vitro Study of Local Oxygen Therapy as Adjunctive Antimicrobial Therapeutic Option for Patients with Periodontitis.

Periodontitis is a common global disease caused by bacterial dysbiosis leading to tissue destruction, and it is strongly associated with anaerobic bacterial colonization. Therapeutic strategies such as oxygen therapy have been developed to positively influence the dysbiotic microbiota, and the use of oxygen-releasing substances may offer an added benefit of avoiding systemic effects commonly associated with antibiotics taken orally or hyperbaric oxygen therapy. Therefore, the oxygen release of calcium peroxide (CaO2) was measured using a dissolved oxygen meter, and CaO2 solutions were prepared by dissolving autoclaved CaO2 in sterile filtered and deionized water. The effects of CaO2 on planktonic bacterial growth and metabolic activity, as well as on biofilms of Streptococcus oralis and Porphyromonas gingivalis, were investigated through experiments conducted under anaerobic conditions. The objective of this study was to investigate the potential of CaO2 as an antimicrobial agent for the treatment of periodontitis. Results showed that CaO2 selectively inhibited the growth and viability of P. gingivalis (p < 0.001) but had little effect on S. oralis (p < 0.01), indicating that CaO2 has the potential to selectively affect both planktonic bacteria and mono-species biofilms of P. gingivalis. The results of this study suggest that CaO2 could be a promising antimicrobial agent with selective activity for the treatment of periodontitis.

Determination of Physico-Chemical Parameters of St. Nicholas River, Bayelsa State, Niger Delta, Nigeria

The Physicochemical parameters of St. Nicholas River were determined from October, 2020 to September, 2021. Three sampling stations were identified and used throughout the duration of the studies. They were Meinmokiri, Ebierewo-bugo and Egeinkiri sampling stations. The physicochemical parameters were measured in situ with Mercury in Glass Thermometer for Temperature, Hand held Digital Salinometer for (Model AR8012) for Salinity, pH meter (Model PH-009(1)) for pH, Digital conductivity tester (Model AR8011) for Conductivity, TDS meter (Model AR8012) for Total Dissolved Solid, Digital Water Velocity meter (Model PF LV550) for Water Velocity, Secchi Disk for Transparency, Digital Depth Founder (Model SD-5) for Water Depth and Dissolved Oxygen Meter (Model OM-51-10) for Dissolved Oxygen. The mean values of the Physicochemical parameters of water at the three sampling stations are temperature; 29.98±0.550C, Dissolved Oxygen DO; 11.89±0.33mg/L, Biochemical Oxygen Demand BOD; 2.06±0.26 mg/L, Salinity; 16.80±2.06 PPT, Conductivity; 27.54±3.03µS/cm, Total Dissolved Solids TDS; 9.44±0.50mg/L, pH; 7.41±0.14, Water Depth; 0.58±0.06m, Transparency; 27.27±0.03cm and Water Velocity; 54.79±5.71m3/s. These physicochemical parameters values are comparable with other water bodies in the Niger Delta indicating contaminated waters. The contamination was caused by anthropogenic activities in terms of parameters assessed, therefore mitigation should be put in place for biodiversity conservation and sustainability of the ecosystem.

Rational design of nanoliposomes by tuning their bilayer rigidity for the controlled release of oxygen

The addition of cholesterol and polymers to the phospholipid envelope of liposomes increases the rigidity of those liposomes, affecting the sustained release of any encapsulated drug. In the present study, to control the oxygen concentration in cells or tissue, oxygen-dissolved nanoliposomes (ODLs) consisting of a phospholipid envelope and an oxygen core were produced. To control the oxygen release rate, the bilayer rigidity was increased by adding cholesterol and a polymer to the phospholipid envelope of the ODLs. Using cryo-transmission electron microscopy and small-angle x-ray scattering, we confirmed the size of the ODLs and the thickness of the bilayered shell following the addition of the cholesterol and polymer. The effect of the increase in the envelope thickness and stiffness on the oxygen release rate was determined using a dissolved oxygen meter. The ODLs were not cytotoxic for HeLa or human dermal fibroblast cells at the tested concentrations, and beneficial changes to their oxygen release rate were observed. Overall, it was found that ODLs with low cytotoxicity and tunable phospholipid envelope components have significant potential as controlled-release carriers of oxygen.

AN ASSESSMENT OF PHYSICOCHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF WATER IN INSUKAMINI CATCHMENT WATER SOURCES AND THE SUITABILITY OF WATER FOR DOMESTIC USE

Insukamini catchment depends on hand dug wells, sand water abstraction, dam, and borehole water sources for their domestic uses. On hand dug wells and sand water abstraction, people rely on natural filtration of bacteria and consider the water as safe, however the location and management of some of these water sources raise suspicion of possible contamination. The aim of this study was to assess drinking water quality in terms of selected physico-chemical and microbiological parameters, and people's perceptions on aesthetic parameters. Water samples were collected from five water sources, namely sand water abstraction, dam, hand dug well, borehole and municipal water. Three samples were collected from each water source to make 63 samples. Temperature, pH, electrical conductivity, and dissolved oxygen measured using HI 9143 dissolved oxygen meter, YSI pH 100, HI 9143 dissolved oxygen meter and HI 8633 conductivity meter respectively. On laboratory experiments total suspended solids measured using filter disk, total dissolved solids using gravimetric method (SA, 2008), total and feacal coliform were measured using spread plate method. All water sources had total coliform levels above the WHO standards for drinking water of 1000mg/L. For E. coli, borehole and municipal water sources complied with the WHO standard with the means of zero cfu/ 100ml. Low pH mean of 5.001 was found in borehole water and the other water sources were within the accepted range of 6.5 to 8.5. Municipal and dam point (A) water sources had highest levels of TDS, borehole, and dam point (C) had TSS levels above maximums allowable of 1000mg/L and 150mg/L respectively. Temperature, DO and EC of all water sources were within the WHO standards. Overall, all water sources were not complying with WHO standard for drinking water. People described municipal water source as best for drinking purpose, dam, sand water abstraction and hand dug well water sources described as soft and good for laundry and bathing as compared to borehole which was described as hard. The results indicated that water from the sources under study were not suitable for drinking purposes without treatment. The water should rather be used for other domestic uses such as laundry and bathing. However, municipal water should be boiled or use water purification tablets (chlorine tablets) before drinking. An integrated approach is therefore required to minimize and avoid water pollution within the catchment.

Development of quantitative and concise measurement method of oxygen in fine bubble dispersion.

Fine bubbles (FBs) have attracted significant attention in several research fields. Although some reports have argued that FB dispersion is useful as an oxygen (gas) carrier, only a few reports have examined its properties as an oxygen carrier using experimental data. As one of the reasons for this, there are no standard methods for measuring the oxygen content in FB dispersions. Conventional oxygen measurement methods have certain drawbacks in accuracy or speed; thus, it is difficult to use oxygen content as the primary outcome. In this study, we introduce a Clark-type polarographic oxygen electrode device (OXYG1-PLUS) for oxygen measurement, allowing the dilution of FB dispersion without the influence of ambient air and the adhesion of FBs on the electrode surface due to its special shape. First, the accuracy of our dilution method was evaluated using pure water as a sample, and it was confirmed that our method could measure with an accuracy of ±0.5 mg/L from the results with conventional dissolved oxygen meters. Second, the oxygen content in FB dispersion was evaluated with our method and a chemical titration method (Winkler’s method), and it was found that our method could measure the oxygen content in FB dispersions quantitively. This method satisfies the easiness (4 steps) and quickness (within 8 min) for a wide range of oxygen contents (0 to 332 mg/L, theoretical range) with low coefficient variation (< 4.7%) and requires a small sample volume (50–500 μL); thus, it is a useful method for measuring the oxygen in FB dispersions.

The impact of sub-lethal concentrations of glyphosate on growth and haematology of African catfish under aquatic ecological micro-climate

The impact of sub-lethal concentrations of glyphosate (Isopropylamine salt - H2NCH(CH3)2) an active ingredient in Roundup® herbicides on growth and haematology of African catfish (Clarias gariepinus) were evaluated under aquatic ecological envirornment. Uncontrolled discharge of glyphosate from agricultural farm land to aquaculture facilities necessitated the study. Sub-lethal concentrations 0.30 mg/l, 0.50 mg/l, 0.70 mg/l and 1.40 mg/l were established after series of range finding tests. Weight (g) and length measurement (cm) were taken on biweekly basis to monitor growth. Behavioural responses to treatment during the range finding tests includes: erratic swimming, loss of balance, mucous secretion, discolouration, hanging on water surface and inactivity. Blood parameters analyzed were Red Blood Cell (RBC), Haemoglobin content (Hb), Packed Cell Volume (PCV), White Blood Cell (WBC), Platelet (PLT), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Haemoglobin Concentration (MCHC). Automated haematology analyser was used to determine the blood parameters. The physico-chemical parameters monitored were temperature, pH, Dissolved Oxygen and Electrical Conductivity. Thermometer, pH meter, dissolved oxygen meter and Electrical conductivity meter respectively were used. The findings of the study demonstrated that exposure for 60 days to the herbicide “glyphosate” at sub-lethal doses of 0.30 mg/l, 0.50 mg/l, 0.70 mg/l and 1.40 mg/l were toxic to Clarias gariepinus and this toxicants were dose-dependent.There was significant difference (P < 0.05) in growth among the treatments. The best growth was recorded in the control (0.00 mg/l) while poorest growth was recorded in 1.40 mg/l. The findings in this study showed that 0.30 mg/l to 1.40 mg/l of the toxicants were harmful to Clarias gariepinus. The report therefore recommended examination of lower concentrations (<0.30 mg/l) in future study to establish the limit beyond which glyphosate should not be allowed in aquaculture system.

Seasonal Fluctuations of Physicochemical Characteristics of Selected Wetlands of Kogi State, North Central, Nigeria

This study is aimed at determining the physicochemical characteristics of selected wetlands of Kogi State. From each sampled wetlands (Abu’ja and Egwubi), surface water was collected and examined for the following physicochemical parameters: hydrogen ion concentration, electrical conductivity, total dissolved solids and temperature (0C) using Hanna meter. Dissolved oxygen was determined using dissolved oxygen meter. The data collected was analyzed using the Statistical Packages for Social Sciences version 20.0, Paleontological Statistics version 3.14 and Microsoft Office. Physicochemical parameters studied were not normally distributed from test of normality. They were compared using Man-Whitney U and Kruskal-Wallis H nonparametric tests for comparisons between two and more than two groups respectively. In Abu’ja wetland, the temperature for all the months were similar except for January and December which were significantly cooler (p &lt; 0.05); pH was similarly constant except for January and August (p &lt; 0.05). Dissolved solids ranged from 95 to 118 ppm with similar values between months except in March. Mean electrical conductivity ranged from 0.15 to 0.22 ms/cm. These values were similar between months in Abu’ja. Significant fluctuation occurred in dissolved oxygen on monthly basis. In Egwubi study station, temperature ranged from 20oC to 31 oC, significant difference occurred between January and May and between September and November (p &lt; 0.05), pH was also similar between months. Dissolved solids ranged from 26 to 90 ppm. Electrical conductivity ranged from 0.2 to 0.14 ms/cm. Significant differences only occurred between April and August (p &lt; 0.05). Dissolved oxygen was similar throughout the study period. Our result indicated that the essential minerals and other physiochemical parameters are widely distributed but some are not within the normal range of portable water for humans. Both study wetlands showed low pollution, organic waste in Abu'ja site may be handled by autochthonous bacteria and through self purification of the water body. Nutrient levels are high in wetland habitats as wetlands have rich biomes and support high level of biodiversity. The water is suitable for irrigation and livestock consumption. The presence of the plankton is a pointer to the fact that the two wetlands possess adequate water quality for establishment of great biodiversity.

Gas-carrying enhances the combustion temperature of the biomass particles

As a clean and renewable energy, high-temperature combustion of biomass is the key to its application in large-scale industrial production. In this study, four different particle size ranges of sawdust i. e, 150–180, 181–250, 251–380 and 381–830 μm were employed to investigate the relationship between particle size and gas-carrying capacity and its influence on combustion temperature. The morphology and structure of the micropores of the sawdust were determined by ESEM and BET methods. The relationship between particle size and gas-carrying capacity was determined by a dissolved oxygen meter, the combustion experiment was conducted on a Hencken flat flame burner coupled with a high-speed camera. The results showed that smallest particle range (150–180 μm) had the largest pore volume (0.49 cm3/g). Smaller particles had a better gas-carrying performance, particles with a size of 150–180 μm could increase the dissolved oxygen (DO) content in water up to 7.84 mg/L. The gas-carrying capacity of sawdust particles had a huge promotion effect on the combustion temperature, the maximum combustion temperature of particles with a size of 150–180 μm was 1296 °C. This work provided a theoretical basis for the high-temperature combustion of biomass and makes it possible for its application in high-temperature industries.

Evaluation of Three Electrochemical Dissolved Oxygen Meters

Dissolved oxygen (DO) is critical for aerobic life in aquatic environments. Rapid and accurate measurements of DO are necessary to quantify the rate of oxygen uptake and maintain optimum conditions in root zones. DO meters are available across a price range of USD99 to more than USD1000. We compared three meters for stability, response time, and accuracy in freshwater [tap water, 0 g⋅L–1 sodium chloride (NaCl)] and saline water (simulated seawater, 35 g⋅L–1 NaCl) across multiple temperatures. The Yellow Springs, Inc. 550A (YSI) and Sper Scientific 850048 (Sper) meters were stable across a range of water temperatures (12–38 °C) and salinity. The Smart Sensor Roeam AR8210 drifted ±50% within minutes after calibration and was not evaluated further. In freshwater, the YSI meter was within 4% and the Sper meter was within 5% of the theoretical value at 12 and 22 °C. Meters were less accurate at 38 °C. The accuracy in saline water was similar to freshwater. Across temperature and salinity, the response time averaged 10 s for the YSI meter and 15 s for the Sper meter. We conclude that the YSI and Sper meters can provide rapid, stable, and accurate measurements of DO.

Slow release of oxygen from carbamide peroxide for promoting the proliferation of human brain microvascular endothelial cells under hypoxia

BackgroundUnder hypoxic conditions, the brain can undergo irreversible damage. The present study aimed to explore new higher-oxygen-content carbamide peroxide (CP) compounds and the effect of their oxygen-releasing property on human brain microvascular endothelial cell (EC) proliferation under in vitro hypoxic conditions.MethodsTwo different additives including alpha-terpineol and sorbic acid were added to the reaction system to obtain the carbamide peroxide of CP-I and CP-II.ResultsWe evaluated the oxygen generation capabilities of CP samples by using a portable dissolved oxygen meter. Consequently, alpha-terpineol as a stabilizer exhibited a unique effect on the oxygen generation of CP. CP-I was uniquely able to promote cell proliferation ability at 10 µg·L−1 for hypoxic conditions, with the proliferation rates being 36.2% compared with the control group. The safety of CP to cells was further verified by calcein-AM/PI staining. Under hypoxic conditions, CP-I at 10 µg·L−1 promoted the migration rate, and the migration rate being 32.37%.ConclusionsThese compounds have the advantages of simple synthesis, long storage time, low cost, and rich oxygen content. Used spectrophotometry, oxygen electrode test, and indicator titration for testing the oxygen production rate and oxygen production. The results indicate that alpha-terpineol is the best additive. CP-I exhibited the highest oxygen content and a superior effect on the cell phenotype than CP-II, especially under hypoxia. This study is the first to report the effects of CP on cells, and provides new therapeutic insights into cerebrovascular injury repair.

ATP Mimics pH-Dependent Dual Peroxidase-Catalase Activities Driving H 2 O 2 Decomposition

Adenosine triphosphate (ATP) is produced mainly in the mitochondrion, and its primary task is to function as a ubiquitous energy currency to meet the cellular metabolic demands in biological system...