Oxygen Meter Research Articles

Offspring from Mouse Embryos Developed Using a Simple Incubator-Free Culture System with a Deoxidizing Agent

To culture preimplantation embryos in vitro, water-jacketed CO2 incubators are used widely for maintaining an optimal culture environment in terms of gas phase, temperature and humidity. We investigated the possibility of mouse embryo culture in a plastic bag kept at 37°C. Zygotes derived from in vitro fertilization or collected from naturally mated B6D2F1 female mice were put in a drop of medium on a plastic culture dish and then placed in a commercially available plastic bag. When these were placed in an oven under air at 37°C for 96 h, the rate of blastocyst development and the cell numbers of embryos decreased. However, when the concentration of O2 was reduced to 5% using a deoxidizing agent and a small oxygen meter, most zygotes developed into blastocysts. These blastocysts were judged normal according to their cell number, Oct3/4 and Cdx2 gene expression levels, the apoptosis rate and the potential for full-term development after embryo transfer to pseudopregnant recipients. Furthermore, using this system, normal offspring were obtained simply by keeping the bag on a warming plate. This culture method was applied successfully to both hybrid and inbred strains. In addition, because the developing embryos could be observed through the transparent wall of the bag, it was possible to capture time-lapse images of live embryos until the blastocyst stage without needing an expensive microscope-based incubation chamber. These results suggest that mouse zygotes are more resilient to their environment than generally believed. This method might prove useful in economical culture systems or for the international shipment of embryos.

A BOD Sensor Using Immobilized Microbial Consortium in Alginate–Based Matrix for Rapid Detection of River Water Pollution

The development of a rapid sensor for Biochemical Oxygen Demand (BOD) is important for rapid determination of the degree of pollution in river water. A short–term BOD (BODst) has been developed using a consortium of locally isolated bacteria as the sensing element. YSI 52 Dissolved Oxygen Meter has been used to measure the oxygen uptake in the test solutions. Of the three alginate–based matrices, namely calcium alginate, calcium alginate–gluteraldehyde and polyvinyl alcohol–sodium alginate (PVA-SA), calcium alginate–gluteraldehyde was found to be the best microbial immobilization method. Typical response time of the developed BODst sensor was 8 minutes, and the immobilized microorganisms were suitable for single use. BOD response was observed at 37°C and pH7.0. For river waters, the BOD values estimated by the BODst biosensor correlated well with those determined by conventional BOD5 test using artificial wastewater (AWW) as the calibration solution.

The Influence of the Impeller Shape on Hydrogen Removal from Liquid Aluminium - Physical Model

Today the barbotage process is commonly used for refining aluminium and its alloys. There are many refining reactors available all over the world. The refining gas can be introduced to the liquid metal by nozzles, ceramic porous plugs and rotary impellers. The last ones become the most popular. The shape of impellers is different and influences the level of gas dispersion in the liquid metal. Physical modelling is quite often used for modelling the aluminium barbotage process. In this way it is possible to observe the phenomena that take place in the whole process. Results obtained from this kind of research can be representative and transformed to real conditions if the test stand is built according to the theory of similarity. The test stand was built for modelling the refining process in the URO-200 reactor. Three different shapes of impellers were tested. The processing parameters like the flow rate of refining gas and the impeller rotary speed changed in the range from 5 to 15 dm3/min and from 0 to 500 rpm respectively. Additionally the research of oxygen removal from water was carried out as an analogy of hydrogen removal from liquid aluminium. The level of oxygen was measured by means of oxygen meter Elmetron CO-401. The obtained results were discussed and graphically presented.

Development and Realization of the Software for Dissolved Oxygen Controller

In order to collect dissolved Oxygen values in the target environment periodically, the controlling software for dissolved oxygen meter is developed based on Visual C++, which can gather and save data periodically to provide follow-up analysis with data support. This paper introduces the Dissolved Oxygen Controller instruction code and RS485 communication process, and finally show the complete software user interface and features.

Development of Zirconia Based Oxygen Sensor for Lead and Lead-Bismuth Eutectic

Nanocrystalline yttria stabilized zirconia (YSZ) solid electrolyte powders of composition ZrO2-5 mol% Y2O3 were prepared through modified Pechini process and were characterized. Sintered compacts of these powders in form of pellets had 96% of the theoretical density and helium leak rate <10-9 S cc /s. Using a pellet of this electrolyte in a galvanic cell with different oxygen partial pressures across it, emf was measured as a function of temperature and thus qualified for sensor application. Towards the fabrication of the oxygen sensor for Pb and LBE loop, a compact design wherein a YSZ pellet, glass soldered to a metallic component had been chosen for the oxygen meter.

A NOVEL BIOSENSOR BASED ON Lactobacillus acidophilus FOR DETERMINATION OF PHENOLIC COMPOUNDS IN MILK PRODUCTS AND WASTEWATER

Different branches of industry need to use phenolic compounds (PCs) in their production, so determination of PCs sensitively, accurately, rapidly, and economically is very important. For the sensitive determination of PCs, some biosensors based on pure polyphenol oxidase, plant tissu,e and microorganisms were developed before. But there has been no study to develop a microbial phenolic compounds biosensor based on Lactobacillus species, which contain polyphenol oxidase enzyme. In this study, we used different forms of Lactobacillus species as enzyme sources of biosensor and compared biosensor performances of these forms for determination of PCs. For this purpose, we used lyophilized Lactobacillus cells (containing L. bulgaricus, L. acidophilus, Streptococcus thermophilus), pure L. acidophilus, pure L. bulgaricus, and L. acidophilus- and L. bulgaricus adapted to catechol in Lactobacilli MRS Broth. The most suitable form was determined and optimization studies of the biosensor were carried out by using this form. For preparing the bioactive layer of the biosensor, the Lactobacillus cells were immobilized in gelatin by using glutaraldehyde. In the study, we used catechol as a substrate. Phenolic compound determination is based on the assay of the differences on the respiration activity of the cells on the oxygen meter in the absence and the presence of catechol. The microbial biosensor response depends directly on catechol concentration between 0.5 and 5.0 mM with 18 min response time. In the optimization studies of the microbial biosensor the most suitable microorganism amount was found to be 10 mg, and also phosphate buffer (pH 8.0; 50 mM) and 37.5°C were obtained as the optimum working conditions. In the characterization studies of the microbial biosensor some parameters such as substrate specificity on the biosensor response and operational and storage stability were examine. Furthermore, the determination of PC levels in synthetic wastewater, industrial wastewater, and milk products was investigated by using the developed biosensor under optimum conditions.

Experimental Study on Activated Sludge Form Sewage Treatment of Different Oxygen Gradient Reactor

It used dissolved oxygen meter to detect dissolved different oxygen concentration within wastewater treatment reactor and analysed reasons for the formation of oxygen concentration gradient. In order to learn more about activated sludge form of different oxygen gradient in the reactor, biological microscope operated in characteristics of microfauna and activated sludge floc in the reactor has been studied. The results showed that Vorticella and Rotifera could grow normally in the high and low regional areas; there are more abundant micro-fauna species in the area of low oxygen, and the microfauna was more mature than those in the area of high oxygen; activated sludge was brown and floc size was small in the areas of high oxygen, activated sludge was black and floc size was big.

How Mexican biochemistry developed and present challenges

How Mexican biochemistry developed and present challenges

Abstract 75: Electron transport chain-dependent oxygen consumption in metastatic breast cancer cells

Abstract Although mitochondrial ATP-production deficiency has been historically implicated to account for the Warburg effect or “aerobic” glycolysis in cancer cells, recent observations indicate the presence of functionally competent mitochondria in cancer cells. We hypothesized that a lung-metastatic breast cancer cell line with intact mitochondrial membrane potential would exhibit mitochondria-dependent oxygen consumption. A murine breast cancer cell line (4T1) was used to evaluate mitochondrial membrane potential by JC-1 fluorescence microscopy. Oxygen consumption by cancer cells in suspension was determined using a dissolved oxygen meter. Fluorescence microscopy of JC-1 red aggregates indicated the presence of highly polarized mitochondria in 4T1 cells, suggesting that these cells are capable of oxidative phosphorylation. Oxygen consumption rate of 4T1 cells suspended in 10 mM glucose-containing medium equilibrated with 21% oxygen (258 µM dissolved oxygen) at 25°C was 2.98 nmol/min/million cells (Control). Oxygen consumption was significantly enhanced by carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), a mitochondrial uncoupler (7.88 nmol/min/million cells, p<0.05 vs. Control). Myxothiazol (a respiratory chain complex III inhibitor) inhibited the oxygen consumption (0.75 nmol/min/million cells; p<0.05 vs. Control), indicating the presence of a functional electron transport chain. A nitric oxide donor also inhibited oxygen consumption (0.84 nmol/min/million cells; p<0.05 vs. Control). These data indicate the presence of oxidative phosphorylation-competent mitochondria in breast cancer cells. We conclude that cancer cells possess respiration-capable mitochondria and their “aerobic” glycolysis may not reflect a compensatory mechanism for ATP generation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 75.

Complex studies of the Azov, Black, and Caspian seas performed on the Deneb survey vessel in 2007

The study of the modern environmental processes taking place in the Azov and Black seas and in the Caspian region of Russia is one the priority tasks of the Southern Scientific Center of the Russian Academy of Sciences (SSC RAS). The SSC RAS, together with the Murmansk Marine Biological Institute of the Kola Scientific Center of the Russian Academy of Science, has been performing annual marine studies in the south of Russia in the last 10 years [1‐11]. The marine fishing vessel Deneb was bought and upgraded in December 2006, which has significantly allowed expanding the geography of the studies and the volume of the work. In 2007, the survey vessel Deneb performed 4 complex expeditions in the Azov, Black, and Caspian seas (table, Fig. 1). The complex studies included the following: meteorological observations, the study of the hydrological‐hydrochemical regime and the features of the spatial distribution of the plankton and benthos, palaeoecological studies, and realization of ship born observations of birds and marine mammals. The studies were carried out in correspondence with the conventional methods and guidelines for oceanographic studies. Standard equipment was used during the field work: STD probes; Apshtein, Judy, and X plankton nets; Petersen’s and van Vin’s bottom samplers; uniflow sediment tubes; Molchanov’s and BM-48 bathometers; oxygen and pH meters; photocolorimeters; etc. Field chemical analyses (oxygen, hydrogen sulfide, and biogenic elements) were performed in the ship’s chemical laboratory. The analysis of the carbon and nitrogen in the water and the bottom sediments, the analysis of the water ionic composition, and the determination of the heavy metals and oil products were performed in the complex interdisciplinary laboratory of the center using appropriate equipment (a Multi N/C 3100 analyzer, a Kapel’-105 device for capillary electrophoresis, a Kvant Z-ETA atomic absorption spectrometer, and a Spectrum BX FT-IR IR Fourier spectrophotometer). Azov Sea. The marine studies were carried out in the spring (after a mild winter; the temperatures of the air and water were above 0°e with a lack of ice cover), the summer (with anomalously high temperatures of the air and water), and the autumn of 2007. The seasonal fluctuations of the hydrological‐hydrochemical and hydrobiological regime of the water body were studied in the Azov sea. Spring. In the spring period, the expedition took place at increasing cyclonic activity accompanied by relatively low air temperatures ( 7.4–12.0°e ) and a strong east wind (up to 9 m/s). The spatial distribution of the thermohaline fields was studied along the Taganrog‐Kerch’ transect, and it was found that the temperature fluctuated from 12.0 to 9.0°e and the salinity within 3.45‐17.24‰. A stable vertical temperature gradient equal to 0.22°e /m was found in the southeastern part of the sea. The intensive wind agitation conditioned the low clarity of the sea’s water—from 0.4 m in the Taganrog Gulf to 3.5 m in the Kerch strait. The oxygen content in the surface and bottom layers was within 86‐142% and 87‐129% correspondingly, with relatively even distribution over the depth. The biogenic elements’ concentration range was 0‐2 µ g/l for nitrites, 0‐72 µ g/l for nitrates, and 0‐32 µ g/l for phosphates in the surface layer and 0‐13 µ g/l, 0‐20 µ g/l, and 0‐4.5 µ g/l in the bottom layer, correspondingly. A site with an anomaINFORMATION

Fluorescent microparticles for sensing cell microenvironment oxygen levels within 3D scaffolds

We present the development and characterization of fluorescent oxygen-sensing microparticles designed for measuring oxygen concentration in microenvironments existing within standard cell culture and transparent three-dimensional (3D) cell scaffolds. The microparticle synthesis employs poly(dimethylsiloxane) to encapsulate silica gel particles bound with an oxygen-sensitive luminophore as well as a reference or normalization fluorophore that is insensitive to oxygen. We developed a rapid, automated and non-invasive sensor analysis method based on fluorescence microscopy to measure oxygen concentration in a hydrogel scaffold. We demonstrate that the microparticles are non-cytotoxic and that their response is comparable to that of a traditional dissolved oxygen meter. Microparticle size (5–40μm) was selected for microscale-mapping of oxygen concentration to allow measurements local to individual cells. Two methods of calibration were evaluated and revealed that the sensor system enables characterization of a range of hypoxic to hyperoxic conditions relevant to cell and tissue biology (i.e., pO2 10–160mmHg). The calibration analysis also revealed that the microparticles have a high fraction of quenched luminophore (0.90±0.02), indicating that the reported approach provides significant advantages for sensor performance. This study thus reports a versatile oxygen-sensing technology that enables future correlations of local oxygen concentration with individual cell response in cultured engineered tissues.

Thermo Fisher Scientific introduces dissolved oxygen meters

US-based Thermo Fisher Scientific Incorporated has unveiled the new Thermo Scientific Orion Star Series rugged dissolved oxygen (RDO) meters, sensors and accessories.

Concentration determination of oxygen nanobubbles in electrolyzed water

Water electrolysis is well known to produce solutions supersaturated with oxygen. The oxygen in electrolyzed solutions was analyzed with a dissolved oxygen meter and the Winkler method of chemical analysis. The concentration of oxygen measured with the dissolved oxygen meter agreed with that obtained using the Winkler method. However, measurements using a 10-fold dilution method showed a larger concentration of dissolved oxygen compared to the above methods. We developed a modified Winkler method to measure total oxygen concentration more accurately, which agreed with the results obtained from the 10-fold dilution experiment. The difference in measurements is due to the existence of oxygen nanobubbles, as confirmed by the observation of dynamic light scattering using a laser. Further analysis of the oxygen nanobubbles demonstrated that the stability of the nanobubbles was sufficient for chemical reaction and solvation to bulk solution.

Oxygen release of tetra acetyl ethylene diamine (TAED) and sodium perborate combination

To evaluate the effect of tetra acetyl ethylene diamine (TAED) on oxygen release from sodium perborate and to compare it with sodium perborate-hydrogen peroxide (H(2)O(2)) and sodium perborate-distilled water mixtures. Six groups were evaluated: control groups (groups I-III), sodium perborate was mixed with distilled water or 3% or 30% H(2)O(2); experimental groups (groups IV-VI), sodium perborate was mixed with TAED in different ratios and then distilled water was added to these mixtures. The amount of oxygen released from the samples was measured with a digital oxygen meter at room temperature (25 degrees C) and body temperature (37 degrees C) after 1 min, 1-6 h and 12 h and on each day up to 1 week. The results were statistically evaluated by one-way analysis of variance and post hoc Tukey's tests. The TAED groups demonstrated significantly higher amounts of released oxygen after 1 min and 1 h at 25 degrees C and 1 min at 37 degrees C (P < 0.05). At all other measurement times, the amount of TAED in each mixture did not alter the amount or speed of oxygen release (P > 0.05). Tetra acetyl ethylene diamine groups achieved their maximum oxygen release 2 h earlier at 25 degrees C and 1 h earlier at 37 degrees C than the other groups. Thus, TAED accelerated oxygen release from sodium perborate-distilled water mixtures regardless of its proportions up to 24 h.

Production of active PET films: evaluation of scavenging activity

AbstractThe current trends in packaging technology are focusing on the development of functional materials that interact with the environment and with the food, playing an effective role in the preservation of quality. In particular, the so‐called active packaging technologies were developed as a response to the market needs for minimally treated foodstuffs, in order to preserve their freshness and flavours by regulating the gas composition of the packaging headspace through active scavengers. One of the most promising approaches for this technology is the incorporation of active scavengers into a polymeric matrix. Nevertheless, the design and the production of a functional and efficient active flexible package can be difficult to realize because of the complexity of the system. This work was thus focused on the production and the analysis of monolayer polyester films containing an oxygen scavenger. The active film was obtained by adding the active phase into a polyethylene terephthalate matrix during the extrusion process. The barrier properties of the films were investigated by means of conventional permeability measurement, to assess their activity with respect to oxygen. Additionally, the oxygen absorption of the active samples was analysed by an innovative oxygen meter system, in order to determine their scavenging capacity and reaction kinetics. The analysis of colour was carried out on packaged fresh apple slices, to verify if the active films produced were able to limit the oxidation processes on a sensitive food. Finally, the optical properties of the samples were investigated through haze measurements. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Dynamics of invertebrate communities on the stony littoral of the Neva Estuary (Baltic Sea) under macroalgal blooms and bioinvasions

1 - The Littoral zone of the Neva Estuary is strongly influenced by (mainly Cladophora glomerata). The present paper aims to study species composition, abundance and seasonal dynamics of littoral invertebrate communities in the Neva Estuary in order to assess their current status and the influence of macroalgal blooms on invertebrates. 2 - Littoral communities at three sites in the Neva Estuary were monitored during May to October of 2002, 2004 and 2005. Quantitative sampling of macroinvertebrates at a depth of 0.5 m was carried out with a 0.03 m2 cylindrical metal frame. Temperature, conductivity, dissolved oxygen and total phosphorus in water were measured at studied sites using a WTW Oxi330 oxygen meter, a DistWP4 conductivity meter and standard analytic techniques. 3 - A list of macroinvertebrate species includes 104 taxa in the freshwater part of the Neva Estuary and considerably fewer in its oligohaline part due to the disappearance of some species of typical freshwater groups (oligochaetes and dipterans). Amphipods Gmelinoides fasciatus and Pontogammarus robustoides, recent invaders to the Neva Estuary, were abundant species at all studied habitats of the estuary, accounting for 73% of the total biomass of zoobenthos. 4 - We obtained significant positive correlations between the density of invertebrate groups (oligochaetes, chironomids, ephemeropterans, trichopterans, amphipods) and oxygen content in water. Temporary hypoxia (0.62–2.8 mgl-1) and a 4-10-fold decrease in the density of amphipods, oligochaetes and aquatic insects were recorded in littoral habitats during decomposition of drifting filamentous algae (July-August). We conclude that intensive macroalgal blooms in the littoral zone due to the intense eutrophication of the Neva Estuary can negatively affect the density of intolerant species and groups and the structure of the invertebrate community through deterioration of oxygen conditions and increase of nutrients during intensive decomposition of drifting algae.

A NOVEL METHOD TO OXYGENATE INTRAOCULAR IRRIGATION FLUIDS WITH AN IN-LINE OXYGENATOR

We describe a novel method to oxygenate intraocular irrigation solutions involving an in-line oxygenator. Either lactated Ringer (LR) solution or balanced salt solution (BSS) was oxygenated with the FE390 Stainless In-line Oxygenation Assembly (Beer, Beer, and More Beer, Concord, CA). After running a 100-mL of solution through the in-line oxygenator, oxygen saturation was measured with a dissolved oxygen meter. A control experiment involving the oxygenator without oxygen perfusion was performed. Paired t-tests were used to compare oxygen saturation changes before and after oxygenation. In comparison with the original BSS, there was an increase in oxygen saturation of 162 +/- 47% (n = 40; P < 0.05). Without oxygenation perfusion, there was only a 24 +/- 14% (n = 40) increase in oxygen levels in BSS, which was significantly lower than that in treated BSS (P < 0.05). In comparison with the original LR solution, there was an increase in oxygen saturation of 208 +/- 21% (n = 40; P < 0.05). Without oxygenation perfusion, there was only a 21 +/- 9% (n = 40) gain in oxygen saturation in the control LR solution, which was statistically lower as well (P < 0.05). The in-line oxygenator is an efficient tool for oxygenating BSS and LR solution. It represents a potential efficient and convenient method to oxygenate irrigating solutions for vitreoretinal surgeries.

Characterization of mitochondria in cisplatin-resistant human ovarian carcinoma cells

One of the mechanisms of cisplatin cell cytotoxicity is the mitochondria-associated induction of apoptosis. The morphological or functional change of mitochondria in cisplatin-resistant cells has already been reported. Herein we present additional data describing the mitochondrial genomic and functional changes in cisplatin- resistant cells. Cisplatin increased the level of apoptotic cells in cisplatin-sensitive human ovarian carcinoma OV 2008 and C13 cells by 3.90+/-1.01 (SD; N=3) (p<0.01)-fold and 2.03+/-0.20 (SD; N=3) (p<0.01)-fold compared to the basal apoptotic level. This indicates a lower level induction of apoptosis by 50% in cisplatin-resistant OV 2008/C13 *5.25 variant (C13) cells. In both cell types, cisplatin cytotoxicity is mostly inhibited by the caspase-9 inhibitor as well as the caspase-3 inhibitor, Ac-DEVD-CHO, suggesting that the mitochondrial downstream event was functioning well in both the C13 cells and in OV 2008 cells. Mitochondrial transmembrane potential (DeltaPsim) determined by flow cytometry using DiOC6-stained cells revealed a significant depolarization of C13 cells as compared to OV 2008 cells. Treatment of these cells with cisplatin or hydrogen peroxide induces complete mitochondrial DNA damage in OV 2008 cells, while only partial DNA-destruction is observed in C13 cells, strongly suggesting that mitochondria are resistant to cisplatin and oxidative stress response. Continuous oxygen consumption of these cells monitored by a multi-channel dissolved oxygen meter is 1.70-fold higher in OV 2008 cells than C13 cells and the oxygen consumption was decreased by 30% in C13 cells, suggesting mitochondrial respiratory malfunction in these cells. The hypothesis generated here is that mitochondrial DNA resistance to cisplatin and oxidative stress response might be one of the main characteristics concerning the lower level of apoptosis induced by cisplatin. However, the mechanism by which the mitochondrial DNA encoded molecule is involved in cisplatin resistance remains to be determined.

Effect of sodium azide on the metabolic activity of cultured fetal cells

Sodium azide is a highly toxic substance. However, the mechanism of its toxicity has not been fully established. In the present study, we attempted to investigate the toxicity of sodium azide in various cultured fetal cells, using changes in cellular respiration as an indicator of metabolic inhibition to elucidate tissue-specificity. The human fetal cell lines used in this study included myocardial cells, nerve cells, fibroblasts, hepatocytes and renal tubular epithelial cells. The cells were seeded in wells at a density of 2 x 10(6)cells/2mL, sodium azide was added at a concentration of 0.01 ng/mL to 10 microg/mL, and the respiration of each type of cell was measured 1 h later using a dissolved oxygen meter. The concentration at which sodium azide inhibited metabolic activity was lower in the nerve and myocardial cells than in the fibroblasts, hepatocytes and renal tubular epithelial cells. These findings may serve to clarify the dynamic mechanisms of sodium azide toxicity in vivo.

Effects of Deaeration Methods on Dissolution Testing in Aqueous Media: A Study Using a Total Dissolved Gas Pressure Meter

Dissolution testing is a critical method for the determination of pharmaceutical product quality and bioequivalence. For some products, dissolved gases in the dissolution medium affect dissolution results thus requiring degassing of the medium prior to use. In this study, we use a total dissolved gas and oxygen meter to measure both oxygen and total gases in dissolution media before and after application of a variety of deaeration methods. Dissolution testing results using a 10 mg Prednisone tablet (NCDA #2) are compared with the percent saturation of oxygen and total gases found in the medium. Reaeration of the medium during different stirring rates was also measured. This study confirms that measurement of total gases and not just oxygen in the medium is necessary to assess adequacy for dissolution testing. For those deaeration techniques that are performed at room temperature, the percent saturation of the total dissolved gases must be well below 100% to prevent outgassing once medium is brought to dissolution test method temperature, typically 37 degrees C.