Dissolved oxygen in the Tualatin River, Oregon, during winter flow conditions, 1991 and 1992

USGS Publications Warehouse

Kelly, V.J.

1996-01-01

Throughout the winter period, November through April, wastewater treatment plants in the Tualatin River Basin discharge from 10,000 to 15,000 pounds per day of biochemical oxygen demand to the river. These loads often increase substantially during storms when streamflow is high. During the early winter season, when streamflow is frequently less than the average winter flow, the treatment plants discharge about 2,000 pounds per day of ammonia. This study focused on the capacity of the Tualatin River to assimilat oxygen-demanding loads under winter streamflow conditions during the 1992 water year, with an emphasis on peak-flow conditions in the river, and winter-base-flow conditions during November 1992. Concentrations of dissolved oxygen throughout the main stem of the river during the winter remained generally high relative to the State standard for Oregon of 6 milligrams per liter. The most important factors controlling oxygen consumption during winter-low-flow conditions were carbonaceous biochemical oxygen demand and input of oxygen-depleted waters from tributaries. During peak-flow conditions, reduced travel time and increased dilution associated with the increased streamflow minimized the effect of increased oxygen-demanding loads. During the base-flow period in November 1992, concentrations of dissolved oxygen were consistently below 6 milligrams per liter. A hydrodynamic water-quality model was used to identify the processes depleting dissolved oxygen, including sediment oxygen demand, nitrification, and carbonaceous biochemical oxygen demand. Sediment oxygen demand was the most significant factor; nitrification was also important. Hypothetical scenarios were posed to evaluate the effect of different wastewater treatment plant loads during winter-base-flow conditions. Streamflow and temperature were significant factors governing concentrations of dissolved oxygen in the main-stem river.

Analysis of nitrogenous and algal oxygen demand in effluent from a system of aerated lagoons followed by polishing pond.

PubMed

Khorsandi, Hassan; Alizadeh, Rahimeh; Tosinejad, Horiyeh; Porghaffar, Hadi

2014-01-01

In this descriptive-analytical study, nitrogenous and algal oxygen demand were assessed for effluent from a system of facultative partially mixed lagoons followed by the polishing pond using 120 grab samples over 1 year. Filtered and non-filtered samples of polishing pond effluent were tested in the presence and absence of a nitrification inhibitor. Effective factors, including 5-day biochemical and chemical oxygen demand (BOD and COD), total suspended solids (TSS), dissolved oxygen, chlorophyll A, and temperature, were measured using standard methods for water and wastewater tests. The results were analyzed using repeated measures analysis of variance with SPSS version 16. Findings show that the annual mean of the total 5-day BOD in the effluent from the polishing pond consisted of 44.92% as the algal carbonaceous biochemical oxygen demand (CBOD), 43.61% as the nitrogenous biochemical oxygen demand (NBOD), and 11.47% as the soluble CBOD. According to this study, the annual mean ratios of algal COD and 5-day algal CBOD to TSS were 0.8 and 0.37, respectively. As the results demonstrate, undertaking quality evaluation of the final effluent from the lagoons without considering nitrogenous and algal oxygen demand would undermine effluent quality assessment and interpretation of the performance of the wastewater treatment plant.

Loads of suspended sediment and nutrients from local nonpoint sources to the tidal Potomac River and Estuary, Maryland and Virginia, 1979-81 water years

USGS Publications Warehouse

Hickman, R. Edward

1987-01-01

Loads of suspended sediment, phosphorus, nitrogen, biochemical oxygen demand, and dissolved silica discharged to the tidal Potomac River and Estuary during the !979-81 water years from three local nonpoint sources have been calculated. The loads in rain falling directly upon the tidal water surface and from overflows of the combined sewer system of the District of Columbia were determined from available information. Loads of materials in the streamflow from local watersheds draining directly to the tidal Potomac River and Estuary downstream from Chain Bridge in Washington, D.C., were calculated from samples of streamflow leaving five monitored watersheds. Average annual yields of substances leaving three urban watersheds (Rock Creek and the Northwest and Northeast Branches of the Anacostia River) and the rural Saint Clements Creek watershed were calculated either by developing relationships between concentration and streamflow or by using the mean of measured concentrations. Yields calculated for the 1979-81 water years are up to 2.3 times period-of-record yields because of greater than average streamflow and stormflow during this 3-year period. Period-of-record yields of suspended sediment from the three urban watersheds and the Saint Clements Creek watershed do not agree with yields reported by other studies. The yields from the urban watersheds are 17 to 51 percent of yields calculated using sediment-concentration data collected during the 1960-62 water years. Previous studies suggest that this decrease is at least partly due to the imposition of effective sediment controls at construction sites and to the construction of two multipurpose reservoirs. The yield calculated for the rural Saint Clements Creek watershed is at least twice the yields calculated for other rural watersheds, a result that may be due to most of the samples of this stream being taken during the summer of the 1981 water year, a very dry period. Loads discharged from all local tributary watersheds to the tidal Potomac River and Estuary during the 1979-81 water years were calculated by applying to the unsampled watersheds the yields determined for the monitored watersheds. The resulting loads are 2.7 million megagrams of suspended sedi- ment, 3,100 megagrams of phosphorus, 14,000 megagrams of nitrogen, 74,000 megagrams of ultimate biochemical oxygen demand, and 68,000 megagrams of dissolved silica. The value for the load of sediment is probably an overestimate because the sediment yield calculated for the Saint Clements Creek watershed does not appear to be representative of rural watersheds. Summed, the loads discharged from all local nonpoint sources (local tributary watersheds, rainfall, and combined sewer overflows) to the tidal Potomac River and Estuary during the 1979-81 water years are 2.7 million megagrams of suspended sediment, 3,300 megagrams of phosphorus, 18,000 megagrams of nitrogen, 78,000 megagrams of ultimate biochemical oxygen demand, and 69,000 megagrams of dissolved silica. These loads accounted for 17 to 38 percent of the loads discharged by major sources during this period.

Dissolved-oxygen regime of the Jordan River, Salt Lake County, Utah

USGS Publications Warehouse

Stephens, D.W.

1984-01-01

Concentrations of dissolved oxygen in the Jordan River in Salt Lake County decrease considerably as the river flows northward. Mean concentrations of dissolved oxygen decreased from 8.1 milligrams per liter at the Jordan Narrows to 4.7 milligrams per liter at 500 North Street during April 1981 to September 1982. Coincident with the decrease, the biochemical-oxygen demand increased from 5 to 7 milligrams per liter. About 50 percent of the dissolved-oxygen concentrations and 90 percent of the 5-day biochemical-oxygen demand measured downstream from 1700 South Street exceeded the State intended-use standards. An estimated 6. million pounds of oxygen-demanding substances as measured by 5-day biochemical-oxygen demand were discharged to the Jordan River during 1981 from point sources downstream from 9000 South Street. Seven wastewater-treatment plants contributed 77 percent of this load, nonstorm base flows contributed 22 percent, and storm flows less than 1 percent. The Surplus Canal diversion at 2100 South Street removed about 70 percent of this load, and travel time of about 1 day also decreased the actual effects of the load on the river. Reaeration rates during September and October were quite high (average K2 at 20 degrees Celsius was about 12 per day) between the Jordan Narrows and 9000 South Street, but they decreased to 2.4 per day in the reach from 1330 South to 1800 North Streets. (USGS)

The Effects of Direct Oxygen Supply During Static Cold Preservation of Rat Livers: An Experimental Study.

PubMed

Zumrutdal, Emin; Karateke, Faruk; Eser, Pınar Eylem; Turan, Umit; Ozyazici, Sefa; Sozutek, Alper; Gulkaya, Mustafa; Kunt, Mevlut

2016-12-01

We aimed to determine the biochemical and histopathologic effects of direct oxygen supply to the preservation fluid of static cold storage system with a simple method on rat livers. Sixteen rats were randomly divided into 2 groups: the control group, which contained Ringer's lactate as preservation fluid; and the oxygen group, which contained oxygen and Ringer's lactate for preservation. Each liver was placed in a bag containing 50 mL Ringer's lactate and placed in ice-filled storage containers. One hundred percent oxygen supplies were given via a simple, inexpensive system created in our laboratory, to the livers in oxygen group. We obtained samples for histopathologic evaluation in the 12th hour. In addition, 3 mL of preservation fluid was subjected to biochemical analysis at 0, sixth, and twelfth hours. Aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and pH levels were measured from the preservation fluid. In oxygen-supplemented group, the acceleration speed of increase in alanine aminotransferase and lactate dehydrogenase levels at sixth hour and lactate dehydrogenase, alanine aminotransferase, and lactate dehydrogenase levels at 12th hour were statistically significantly reduced. In histopathologic examination, all parameters except ballooning were statistically significantly better in the oxygen-supplemented group. This simple system for oxygenation of liver tissues during static cold storage was shown to be effective with good results in biochemical and histopathologic assessments. Because this is a simple, inexpensive, and easily available method, larger studies are warranted to evaluate its effects (especially in humans).

40 CFR Appendix B to Subpart E of... - Federal Guidelines-User Charges for Operation and Maintenance of Publicly Owned Treatment Works

Code of Federal Regulations, 2014 CFR

2014-07-01

... characteristics; i.e., levels of biochemical oxygen demand, suspended solids, etc. Each class is then assigned its... all users per unit of time. Bc = O&M cost for treatment of a unit of biochemical oxygen demand (BOD... only in cases where the water charge is based on a constant cost per unit of consumption. [39 FR 5270...

40 CFR Appendix B to Subpart E of... - Federal Guidelines-User Charges for Operation and Maintenance of Publicly Owned Treatment Works

Code of Federal Regulations, 2012 CFR

2012-07-01

... characteristics; i.e., levels of biochemical oxygen demand, suspended solids, etc. Each class is then assigned its... all users per unit of time. Bc = O&M cost for treatment of a unit of biochemical oxygen demand (BOD... only in cases where the water charge is based on a constant cost per unit of consumption. [39 FR 5270...

40 CFR Appendix B to Subpart E of... - Federal Guidelines-User Charges for Operation and Maintenance of Publicly Owned Treatment Works

Code of Federal Regulations, 2013 CFR

2013-07-01

... characteristics; i.e., levels of biochemical oxygen demand, suspended solids, etc. Each class is then assigned its... all users per unit of time. Bc = O&M cost for treatment of a unit of biochemical oxygen demand (BOD... only in cases where the water charge is based on a constant cost per unit of consumption. [39 FR 5270...

Biogas production from Pongamia biomass wastes and a model to estimate biodegradability from their composition.

PubMed

Gunaseelan, Victor Nallathambi

2014-02-01

In this study, I investigated the chemical characteristics, biochemical methane potential, conversion kinetics and biodegradability of untreated and NaOH-treated Pongamia plant parts, and pod husk and press cake from the biodiesel industry to evaluate their suitability as an alternative feedstock for biogas production. The untreated Pongamia seeds exhibited the maximum CH4 yield of 473 ml g (-1) volatile solid (VS) added. Yellow, withered leaves gave a yield as low as 122 ml CH4 g (-1) VS added. There were significant variations in the CH4 production rate constants, which ranged from 0.02 to 0.15 d (-1), and biodegradability, which ranged from 0.25 to 0.98. NaOH treatment of leaf and pod husk, which were highly rich in fibers, increased the yields by 15-22% and CH4 production rate constants by 20-75%. Utilization of Pongamia wastes in biogas digesters not only influences the economics of biodiesel production but also yields CH4 fuel and protects the environment. The experimental data from this study were used to develop a multiple regression model, which could estimate biodegradability based on biochemical characteristics. The model predicted the biodegradability of previously published biomass wastes (r(2) = 0.88) from their biochemical composition. The theoretical CH4 yields estimated as 350 ml g(-1) chemical oxygen demand destroyed are much higher than the experimental yields as 100% biodegradability is assumed for each substrate. Upon correcting the theoretical CH4 yields with biodegradability data obtained from chemical analyses of substrates, their ultimate CH4 yields could be predicted rapidly.

Controls on biochemical oxygen demand in the upper Klamath River, Oregon

USGS Publications Warehouse

Sullivan, Annett B.; Snyder, Dean M.; Rounds, Stewart A.

2010-01-01

A series of 30-day biochemical oxygen demand (BOD) experiments were conducted on water column samples from a reach of the upper Klamath River that experiences hypoxia and anoxia in summer. Samples were incubated with added nitrification inhibitor to measure carbonaceous BOD (CBOD), untreated to measure total BOD, which included demand from nitrogenous BOD (NBOD), and coarse-filtered to examine the effect of removing large particulate matter. All BOD data were fit well with a two-group model, so named because it considered contributions from both labile and refractory pools of carbon: BODt = a1(1 − e− a0t) + a2t. Site-average labile first-order decay rates a0 ranged from 0.15 to 0.22/day for CBOD and 0.11 to 0.29/day for BOD. Site-average values of refractory zero-order decay rates a2 ranged from 0.13 to 0.25 mg/L/day for CBOD and 0.01 to 0.45 mg/L/day for BOD; the zero-order CBOD decay rate increased from early- to mid-summer. Values of ultimate CBOD for the labile component a1 ranged from 5.5 to 28.8 mg/L for CBOD, and 7.6 to 30.8 mg/L for BOD. Two upstream sites had higher CBOD compared to those downstream. Maximum measured total BOD5 and BOD30 during the study were 26.5 and 55.4 mg/L; minimums were 4.2 and 13.6 mg/L. For most samples, the oxygen demand from the three components considered here were: labile CBOD > NBOD > refractory CBOD, though the relative importance of refractory CBOD to oxygen demand increased over time. Coarse-filtering reduced CBOD for samples with high particulate carbon and high biovolumes of Aphanizomenon flos-aquae. There was a strong positive correlation between BOD, CBOD, and the labile component of CBOD to particulate C and N, with weaker positive correlation to field pH, field dissolved oxygen, and total N. The refractory component of CBOD was not correlated to particulate matter, instead showing weak but statistically significant correlation to dissolved organic carbon, UV absorbance at 254 nm, and total N. Particulate organic matter, especially the alga A.flos-aquae, is an important component of oxygen demand in this reach of the Klamath River, though refractory dissolved organic matter would continue to exert an oxygen demand over longer time periods and as water travels downstream.

Assimilative capacity of the Waccamaw River and the Atlantic Intracoastal Waterway near Myrtle Beach, South Carolina, 1989-92

USGS Publications Warehouse

Drewes, P.A.; Conrads, P.A.

1995-01-01

The assimilative capacities of selected reaches of the Waccamaw River and the Atlantic Intracoastal Waterway near Myrtle Beach, South Carolina, were determined using results from water-quality simulations by the Branched Lagrangian Transport Model. The study area included tidally influenced sections of the Waccamaw River, the Pee Dee River, Bull Creek, and the Atlantic Intracoastal Waterway. Hydrodynamic data for the Branched Lagrangian Transport Model were simulated using the U.S. Geological Survey BRANCH one-dimensional unsteady- flow model. Assimilative capacities were determined for four locations using low-, medium-, and high- flow conditions and the average dissolved-oxygen concentration for a 7-day period. Results indicated that for the Waccamaw River near Conway, the ultimate oxygen demand is 370 to 6,740 pounds per day for 7-day average streamflows of 17 to 1,500 cubic feet per second. For the Waccamaw River at Bucksport, the ultimate oxygen demand is 580 to 7,300 pounds per day for 7-day average streamflows of 62 to 1,180 cubic feet per second. For the Atlantic Intracoastal Waterway near North Myrtle Beach, simulations indicate ultimate oxygen demand is 5,100 to 10,000 pounds per day for 7-day average streamflows of 110 to 465 cubic feet per second. The ultimate oxygen demand for the Waccamaw River near Murrells Inlet is 11,000 to 230,000 pounds per day for 7-day average streamflows of 2,240 to 13,700 cubic feet per second.

A step towards on-chip biochemical energy cascade of microorganisms: carbon dioxide generation induced by ethanol fermentation in 3D printed modular lab-on-a-chip

NASA Astrophysics Data System (ADS)

Podwin, A.; Kubicki, W.; Adamski, K.; Walczak, R.; Dziuban, J. A.

2016-11-01

The concept of biochemical energy cascade of microorganisms towards oxygen generation in 3D printed lab-on-a-chip has been presented. In this work, carbon dioxide - a product of ethanol fermentation of yeasts has been utilized to enable light-initialized photosynthesis of euglenas and as a result of their metabolic transitions produce pure oxygen.

The Roles of Primary Cilia in Cardiovascular System

DTIC Science & Technology

2016-10-01

mitochondrial generation of hydrogen peroxide. General properties and effect of hyperbaric oxygen . Biochem J 134:707–716. Boveris A, Oshino N, Chance B. 1972...The mitochondrial generation of hydrogen peroxide. General properties and effect of hyperbaric oxygen . Biochem J 134:707–716. Boveris A, Oshino N...Aim 1.2 (months 13-30): We will examine signaling mechanisms of cilia & their effects on blood pressure. Aim 2 (months 7-36). We will study

A Review: Some biological effects of high LET radiations

NASA Technical Reports Server (NTRS)

Wiley, A., Jr.

1972-01-01

There are qualitative and quantitative differences in the biological damage observed after exposure to high LET radiation as compared to that caused by low LET radiations. This review is concerned with these differences, which are ultimately reflected at the biochemical, cellular and even whole animal levels. In general, high LET radiations seem to produce biochemical damage which is more severe and possibly less repairable. Experimental data for those effects are presented in terms of biochemical RBE's with consideration of both early and late manifestations. An LET independent process by which significant biochemical damage may result from protons, neutrons and negative pion mesons is discussed.

Water quality of Tampa Bay, Florida, June 1972-May 1976

USGS Publications Warehouse

Goetz, Carole L.; Goodwin, Carl R.

1980-01-01

A comprehensive assessment of the water quality of Tampa Bay, Florida, was initiated in 1970 to provide background information to evaluate the effects of widening and deepening the ship channel to the port of Tampa. This report provides results of water-quality sampling in the bay from 1972 to 1976, prior to dredging. Measurements of temperature, dissolved oxygen, pH, turbidity, specific conductance, biochemical oxygen demand, and total organic carbon were made as well as measurements for several nutrient, metal, and pesticide parameters. Many parameters were measured at as many as three points in the vertical. These data indicate that Tampa Bay is well-mixed vertically with little density stratification. Time histories of average temperature, dissolved oxygen, pH, turbidity, specific conductance and nutrient values within four subareas of Tampa Bay are given to reveal seasonal or other trends during the period of record. Temperature, dissolved oxygen, pH, turbidity, specific conductance, nutrient, biochemical oxygen demand, total organic carbon, and metal data are also presented as areal distributions. Nutrient concentrations were generally higher in Hillsborough Bay than in other sub-areas of Tampa Bay. Biochemical oxygen demand, total organic carbon, and total organic nitrogen distribution patterns show regions of highest concentrations to be along bay shorelines near population centers. Of the metals analyzed, all were present in concentrations of less than 1 milligram per liter. (USGS)

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 1. Biochemical oxygen demand and dissolved oxygen in receiving streams.

PubMed

Corsi, S R; Booth, N L; Hall, D W

2001-07-01

Aircraft and runway deicers are used during cold weather at many of the world's airports to facilitate safe air travel. Propylene glycol-, ethylene glycol-, and urea-based deicers are known to have very high biochemical oxygen demand. At General Mitchell International Airport (GMIA) in Milwaukee, Wisconsin, USA, deicer application, water chemistry, and dissolved oxygen (DO) data were collected for two deicing seasons in order to evaluate and define premanagement water quality parameters prior to the implementation of a glycol management program. Calculations using stream-monitoring data during a controlled release of deicer provided an estimate of 0.8/d for the first-order decay rate constant, substantially higher than published laboratory test results. For eight precipitation events with deicing activities, between 2.4 and 99% of propylene and ethylene glycol applied to aircraft was delivered directly to receiving streams. The percentage of glycol runoff during an event increased with increasing storm-flow volume. Elevated concentrations of glycol and biochemical oxygen demand were measured downstream from the airport. However, the frequency of low DO concentrations in the receiving streams is comparable with that at an upstream reference site. This is possibly due to slowed bacteria metabolism at low water temperatures, short travel times, and dilution from downstream tributaries.

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 1. Biochemical oxygen demand and dissolved oxygen in receiving streams

USGS Publications Warehouse

Corsi, S.R.; Booth, N.L.; Hall, D.W.

2001-01-01

Aircraft and runway deicers are used during cold weather at many of the world's airports to facilitate safe air travel. Propylene glycol-, ethylene glycol-, and urea-based deicers are known to have very high biochemical oxygen demand. At General Mitchell International Airport (GMIA) in Milwaukee, Wisconsin, USA, deicer application, water chemistry, and dissolved oxygen (DO) data were collected for two deicing seasons in order to evaluate and define premanagement water quality parameters prior to the implementation of a glycol management program. Calculations using stream-monitoring data during a controlled release of deicer provided an estimate of 0.8/d for the first-order decay rate constant, substantially higher than published laboratory test results. For eight precipitation events with deicing activities, between 2.4 and 99% of propylene and ethylene glycol applied to aircraft was delivered directly to receiving streams. The percentage of glycol runoff during an event increased with increasing storm-flow volume. Elevated concentrations of glycol and biochemical oxygen demand were measured downstream from the airport. However, the frequency of low DO concentrations in the receiving streams is comparable with that at an upstream reference site. This is possibly due to slowed bacteria metabolism at low water temperatures, short travel times, and dilution from downstream tributaries.

Arsenic speciation and sorption in natural environments

USGS Publications Warehouse

Campbell, Kate M.; Nordstrom, D. Kirk

2014-01-01

Aqueous arsenic speciation, or the chemical forms in which arsenic exists in water, is a challenging, interesting, and complicated aspect of environmental arsenic geochemistry. Arsenic has the ability to form a wide range of chemical bonds with carbon, oxygen, hydrogen, and sulfur, resulting in a large variety of compounds that exhibit a host of chemical and biochemical properties. Besides the intriguing chemical diversity, arsenic also has the rare capacity to capture our imaginations in a way that few elements can duplicate: it invokes images of foul play that range from sinister to comedic (e.g., “inheritance powder” and arsenic-spiked elderberry wine). However, the emergence of serious large-scale human health problems from chronic arsenic exposure in drinking water has placed a high priority on understanding environmental arsenic mobility, toxicity, and bioavailability, and chemical speciation is key to these important questions. Ultimately, the purpose of arsenic speciation research is to predict future occurrences, mitigate contamination, and provide successful management of water resources.

Uncertainty analysis of the simulations of effects of discharging treated wastewater to the Red River of the North at Fargo, North Dakota, and Moorhead, Minnesota

USGS Publications Warehouse

Wesolowski, Edwin A.

1996-01-01

Two separate studies to simulate the effects of discharging treated wastewater to the Red River of the North at Fargo, North Dakota, and Moorhead, Minnesota, have been completed. In the first study, the Red River at Fargo Water-Quality Model was calibrated and verified for icefree conditions. In the second study, the Red River at Fargo Ice-Cover Water-Quality Model was verified for ice-cover conditions.To better understand and apply the Red River at Fargo Water-Quality Model and the Red River at Fargo Ice-Cover Water-Quality Model, the uncertainty associated with simulated constituent concentrations and property values was analyzed and quantified using the Enhanced Stream Water Quality Model-Uncertainty Analysis. The Monte Carlo simulation and first-order error analysis methods were used to analyze the uncertainty in simulated values for six constituents and properties at sites 5, 10, and 14 (upstream to downstream order). The constituents and properties analyzed for uncertainty are specific conductance, total organic nitrogen (reported as nitrogen), total ammonia (reported as nitrogen), total nitrite plus nitrate (reported as nitrogen), 5-day carbonaceous biochemical oxygen demand for ice-cover conditions and ultimate carbonaceous biochemical oxygen demand for ice-free conditions, and dissolved oxygen. Results are given in detail for both the ice-cover and ice-free conditions for specific conductance, total ammonia, and dissolved oxygen.The sensitivity and uncertainty of the simulated constituent concentrations and property values to input variables differ substantially between ice-cover and ice-free conditions. During ice-cover conditions, simulated specific-conductance values are most sensitive to the headwatersource specific-conductance values upstream of site 10 and the point-source specific-conductance values downstream of site 10. These headwater-source and point-source specific-conductance values also are the key sources of uncertainty. Simulated total ammonia concentrations are most sensitive to the point-source total ammonia concentrations at all three sites. Other input variables that contribute substantially to the variability of simulated total ammonia concentrations are the headwater-source total ammonia and the instream reaction coefficient for biological decay of total ammonia to total nitrite. Simulated dissolved-oxygen concentrations at all three sites are most sensitive to headwater-source dissolved-oxygen concentration. This input variable is the key source of variability for simulated dissolved-oxygen concentrations at sites 5 and 10. Headwatersource and point-source dissolved-oxygen concentrations are the key sources of variability for simulated dissolved-oxygen concentrations at site 14.During ice-free conditions, simulated specific-conductance values at all three sites are most sensitive to the headwater-source specific-conductance values. Headwater-source specificconductance values also are the key source of uncertainty. The input variables to which total ammonia and dissolved oxygen are most sensitive vary from site to site and may or may not correspond to the input variables that contribute the most to the variability. The input variables that contribute the most to the variability of simulated total ammonia concentrations are pointsource total ammonia, instream reaction coefficient for biological decay of total ammonia to total nitrite, and Manning's roughness coefficient. The input variables that contribute the most to the variability of simulated dissolved-oxygen concentrations are reaeration rate, sediment oxygen demand rate, and headwater-source algae as chlorophyll a.

Alternative aircraft anti-icing formulations with reduced aquatic toxicity and biochemical oxygen demand

USGS Publications Warehouse

Gold, Harris; Joback, Kevin; Geis, Steven; Bowman, George; Mericas, Dean; Corsi, Steven R.; Ferguson, Lee

2010-01-01

The current research was conducted to identify alternative aircraft and pavement deicer and anti-icer formulations with improved environmental characteristics compared to currently used commercial products (2007). The environmental characteristics of primary concern are the biochemical oxygen demand (BOD) and aquatic toxicity of the fully formulated products. Except when the distinction among products is necessary for clarity, “deicer” will refer to aircraft-deicing fluids (ADFs), aircraft anti-icing fluids (AAFs), and pavementdeicing materials (PDMs).

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for West Fork Blue River, Washington County, Indiana

USGS Publications Warehouse

Peters, James G.; Wilber, W.G.; Crawford, Charles G.; Girardi, F.P.

1979-01-01

A digital computer model calibrated to observe stream conditions was used to evaluate water quality in West Fork Blue River, Washington County, IN. Instream dissolved-oxygen concentration averaged 96.5% of saturation at selected sites on West Fork Blue River during two 24-hour summer surveys. This high dissolved-oxygen concentration reflects small carbonaceous and nitrogenous waste loads; adequate dilution of waste by the stream; and natural reaeration. Nonpoint source waste loads accounted for an average of 53.2% of the total carbonaceous biochemical-oxygen demand and 90.2% of the nitrogenous biochemical-oxygen demand. Waste-load assimilation was studiedfor critical summer and winter low flows. Natural streamflow for these conditions was zero, so no benefit from dilution was provided. The projected stream reaeration capacity was not sufficient to maintain the minimum daily dissolved-oxygen concentration (5 milligrams per liter) in the stream with current waste-discharge restrictions. During winter low flow, ammonia toxicity, rather than dissolved-oxygen concentration, was the limiting water-quality criterion downstream from the Salem wastewater-treatment facility. (USGS)

Combined coagulation-flocculation and sequencing batch reactor with phosphorus adjustment for the treatment of high-strength landfill leachate: experimental kinetics and chemical oxygen demand fractionation.

PubMed

El-Fadel, M; Matar, F; Hashisho, J

2013-05-01

The treatability of high-strength landfill leachate is challenging and relatively limited. This study examines the feasibility of treating high-strength landfill leachate (chemical oxygen demand [COD]: 7,760-11,770 mg/L, biochemical oxygen demand [BOD5]: 2,760-3,569 mg/L, total nitrogen [TN] = 980-1,160 mg/L) using a sequencing batch reactor (SBR) preceded by a coagulation-flocculation process with phosphorus nutritional balance under various mixing and aeration patterns. Simulations were also conducted to define kinetic parameters and COD fractionation. Removal efficiencies reached 89% for BOD5, 60% for COD, and 72% for TN, similar to and better than reported studies, albeit with a relatively lower hydraulic retention time (HRT) and solid retention time (SRT). The coupled experimental and simulation results contribute in filling a gap toward managing high-strength landfill leachate and providing guidelines for corresponding SBR applications. The treatability of high-strength landfill leachate, which is challenging and relatively limited, was demonstrated using a combined coagulation-flocculation with SBR technology and nutrient balance adjustment. The most suitable coagulant, kinetic design parameters, and COD fractionation were defined using coupled experimental and simulation results contributing in filling a gap toward managing high-strength leachate by providing guidelines for corresponding SBR applications and anticipating potential constraints related to the non-biodegradable COD fraction. In this context, while the combined coagulation-flocculation and SBR process improved removal efficiencies, posttreatment may be required for high-strength leachate, depending on discharge standards and ultimate usage of the treated leachate.

Proton transport facilitating water-oxidation: the role of second sphere ligands surrounding the catalytic metal cluster.

PubMed

Bao, Han; Dilbeck, Preston L; Burnap, Robert L

2013-10-01

The ability of PSII to extract electrons from water, with molecular oxygen as a by-product, is a remarkable biochemical and evolutionary innovation. From an evolutionary perspective, the invention of PSII approximately 2.7 Ga led to the accelerated accumulation of biomass in the biosphere and the accumulation of oxygen in the atmosphere, a combination that allowed for the evolution of a much more complex and extensive biosphere than would otherwise have been possible. From the biochemical and enzymatic perspective, PSII is remarkable because of the thermodynamic and kinetic obstacles that needed to have been overcome to oxidize water as the ultimate photosynthetic electron donor. This article focuses on how proton release is an integral part of how these kinetic and thermodynamic obstacles have been overcome: the sequential removal of protons from the active site of H2O-oxidation facilitates the multistep oxidation of the substrate water at the Mn4CaOx, the catalytic heart of the H2O-oxidation reaction. As noted previously, the facilitated deprotonation of the Mn4CaOx cluster exerts a redox-leveling function preventing the accumulation of excess positive charge on the cluster, which might otherwise hinder the already energetically difficult oxidation of water. Using recent results, including the characteristics of site-directed mutants, the role of the second sphere of amino acid ligands and the associated network of water molecules surrounding the Mn4CaOx is discussed in relation to proton transport in other systems. In addition to the redox-leveling function, a trapping function is assigned to the proton release step occurring immediately prior to the dioxygen chemistry. This trapping appears to involve a yet-to-be clarified gating mechanism that facilitates to coordinated release of a proton from the neighborhood of the active site thereby insuring that the backward charge-recombination reaction does not out-compete the forward reaction of dioxygen chemistry during this final step of H2O-oxidation.

Simulation of dissolved oxygen and biochemical oxygen demand, Plantation Canal, Broward County, Florida with an evaluation of the QUAL-I model for use in south Florida

USGS Publications Warehouse

Russo, Thomas N.; McQuivey, Raul S.

1975-01-01

A mathematical model; QUAL-I, developed by the Texas Water Development Board, was evaluated as a management tool in predicting the spatial and temporal distribution of dissolved oxygen and biochemical oxygen demand in Plantation Canal. Predictions based on the QUAL-I model, which was verified only against midday summer-flow conditions, showed that improvement of quality of inflows from sewage treatment plants and use of at least 130 cubic feet per second of dilution water would improve water quality in the canal significantly. The model was not fully amenable to use on Plantation Canal because: (1) it did not consider photosynthetic production, nitrification, and benthic oxygen demand as sources and sinks of oxygen; (2) the model assumptions of complete mixing, transport, and steady state were not met; and (3) the data base was inadequate because it consisted of only one set of data for each case. However, it was felt that meaningful results could be obtained for some sets of conditions. (Woodard-USGS)

Modular 3D printed lab-on-a-chip bio-reactor for the biochemical energy cascade of microorganisms

NASA Astrophysics Data System (ADS)

Podwin, Agnieszka; Dziuban, Jan A.

2017-10-01

The paper presents the sandwiched polymer 3D printed lab-on-a-chip bio-reactor for the biochemical energy cascade of microorganisms. Euglenas and yeast were separately and simultaneously cultured for 10 d in the chip. As a result of the experiments, euglenas, light-initialized and nourished by CO2—a product of ethanol fermentation handled by yeast—generated oxygen, based on the photosynthesis process. The presence of oxygen in the bio-reactor was confirmed by the colorimetric method—a bicarbonate (pH) indicator. Preliminary studies towards the obtainment of an effective source of oxygen are promising and further research should be done to enable the utility of the bio-reactor in, for instance, microbial fuel cells.

What is the Effect of Case-Based Learning on the Academic Achievement of Students on the Topic of "Biochemical Oxygen Demand?"

NASA Astrophysics Data System (ADS)

Günter, Tuğçe; Alpat, Sibel Kılınç

2017-11-01

The purpose of this study was to investigate the effect of the case-based learning (CBL) method used in "biochemical oxygen demand (BOD)," which is a topic taught in the environmental chemistry course, at Dokuz Eylul University, on the academic achievement and opinions of students. The research had a quasi-experimental design and the study group consisted of 4th and 5th grade students (N = 18) attending the Chemistry Teaching Program in a university in Izmir. The "Biochemical Oxygen Demand Achievement Test (BODAT)" and the structured interview form were used as data collection tools. The results of BODAT post-test showed the higher increase in the achievement scores of the experimental group may be an indication of the effectiveness of the CBL method in improving academic achievement in the relevant topic. In addition, the experimental and control group students had positive opinions regarding the method, the scenario, and the material. The students found the method, the scenario, and the material to be interesting, understandable/instructional, relatable with everyday life, suitable for the topic, and enhancing active participation.

An Inexpensive Electrode and Cell for Measurement of Oxygen Uptake in Chemical and Biochemical Systems.

ERIC Educational Resources Information Center

Brunet, Juan E.; And Others

1983-01-01

The continuous measurement of oxygen consumption in an enzymatic reaction is a frequent experimental fact and extremely important in the enzymatic activity of oxygenase. An electrochemical system, based on a polarographic method, has been developed to monitor the oxygen uptake. The system developed and electrode used are described. (JN)

Water-quality characteristics of urban runoff and estimates of annual loads in the Tampa Bay area, Florida, 1975-80

USGS Publications Warehouse

Lopez, M.A.; Giovannelli, R.F.

1984-01-01

Rainfall, runoff, and water quality data were collected at nine urban watersheds in the Tampa Bay area from 1975 to 1980. Watershed drainage area ranged from 0.34 to 0.45 sq mi. Land use was mixed. Development ranged from a mostly residential watershed with a 19% impervious surface, to a commercial-residential watershed with a 61% impervious surface. Average biochemical oxygen demand concentrations of base flow at two sites and of stormwater runoff at five sites exceeded treated sewage effluent standards. Average coliform concentrations of stormwater runoff at all sites were several orders of magnitude greater than standards for Florida Class III receiving water (for recreation or propagation and management of fish and wildlife). Average concentrations of lead and zinc in stormwater runoff were consistently higher than Class III standards. Stormwater-runoff loads and base-flow concentrations of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus, and lead were related to runoff volume, land use, urban development, and antecedent daily rainfall by multiple linear regression. Stormwater-runoff volume was related to pervious area, hydraulically connected impervious surfaces, storm rainfall, and soil-infiltration index. Base-flow daily discharge was related to drainage area and antecedent daily rainfall. The flow regression equations of this report were used to compute 1979 water-year loads of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus , and total lead for the nine Tampa Bay area urban watersheds. (Lantz-PTT)

High-throughput determination of biochemical oxygen demand (BOD) by a microplate-based biosensor.

PubMed

Pang, Hei-Leung; Kwok, Nga-Yan; Chan, Pak-Ho; Yeung, Chi-Hung; Lo, Waihung; Wong, Kwok-Yin

2007-06-01

The use of the conventional 5-day biochemical oxygen demand (BOD5) method in BOD determination is greatly hampered by its time-consuming sampling procedure and its technical difficulty in the handling of a large pool of wastewater samples. Thus, it is highly desirable to develop a fast and high-throughput biosensor for BOD measurements. This paper describes the construction of a microplate-based biosensor consisting of an organically modified silica (ORMOSIL) oxygen sensing film for high-throughput determination of BOD in wastewater. The ORMOSIL oxygen sensing film was prepared by reacting tetramethoxysilane with dimethyldimethoxysilane in the presence of the oxygen-sensitive dye tris(4,7-diphenyl-1,10-phenanthroline)ruthenium-(II) chloride. The silica composite formed a homogeneous, crack-free oxygen sensing film on polystyrene microtiter plates with high stability, and the embedded ruthenium dye interacted with the dissolved oxygen in wastewater according to the Stern-Volmer relation. The bacterium Stenotrophomonas maltophilia was loaded into the ORMOSIL/ PVA composite (deposited on the top of the oxygen sensing film) and used to metabolize the organic compounds in wastewater. This BOD biosensor was found to be able to determine the BOD values of wastewater samples within 20 min by monitoring the dissolved oxygen concentrations. Moreover, the BOD values determined by the BOD biosensor were in good agreement with those obtained by the conventional BOD5 method.

River Pollution: Part I.

ERIC Educational Resources Information Center

Openshaw, Peter

1983-01-01

Describes a unit on river pollution and analytical methods to use in assessing temperature, pH, flow, calcium, chloride, dissolved oxygen, biochemical oxygen demand, dissolved nitrogen, detergents, heavy metals, sewage pollution, conductivity, and sediment cores. Suggests tests to be carried out and discusses significance of results. (JM)

40 CFR 230.22 - Water.

Code of Federal Regulations, 2014 CFR

2014-07-01

... gas levels, pH, and temperature contribute to its life-sustaining capabilities. (b) Possible loss of... populations of aquatic organisms, and for human consumption, recreation, and aesthetics. The introduction of... biochemical oxygen demand (BOD), which in turn can lead to reduced dissolved oxygen, thereby potentially...

40 CFR 230.22 - Water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... gas levels, pH, and temperature contribute to its life-sustaining capabilities. (b) Possible loss of... populations of aquatic organisms, and for human consumption, recreation, and aesthetics. The introduction of... biochemical oxygen demand (BOD), which in turn can lead to reduced dissolved oxygen, thereby potentially...

40 CFR 230.22 - Water.

Code of Federal Regulations, 2013 CFR

2013-07-01

... gas levels, pH, and temperature contribute to its life-sustaining capabilities. (b) Possible loss of... populations of aquatic organisms, and for human consumption, recreation, and aesthetics. The introduction of... biochemical oxygen demand (BOD), which in turn can lead to reduced dissolved oxygen, thereby potentially...

40 CFR 230.22 - Water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... gas levels, pH, and temperature contribute to its life-sustaining capabilities. (b) Possible loss of... populations of aquatic organisms, and for human consumption, recreation, and aesthetics. The introduction of... biochemical oxygen demand (BOD), which in turn can lead to reduced dissolved oxygen, thereby potentially...

40 CFR 230.22 - Water.

Code of Federal Regulations, 2012 CFR

2012-07-01

... gas levels, pH, and temperature contribute to its life-sustaining capabilities. (b) Possible loss of... populations of aquatic organisms, and for human consumption, recreation, and aesthetics. The introduction of... biochemical oxygen demand (BOD), which in turn can lead to reduced dissolved oxygen, thereby potentially...

Effects of silvicultural management on low gradient stream water quality in Louisiana

Treesearch

John Beebe; George Ice; Y. Jun Xu; Abram DaSilva; Richard Stich

2012-01-01

Oxygen depletion in rivers and streams is among the top 5 impairment types most frequently cited in state water quality reports in the U.S., especially in the South. Such impairments require the development of Total Maximum Daily Loads (TMDLs) or other strategies to ameliorate low dissolved oxygen (DO) levels or high biochemical oxygen demand (BOD). TMDLs allocated to...

Unraveling Biochemical Pathways Affected by Mitochondrial Dysfunctions Using Metabolomic Approaches

PubMed Central

Demine, Stéphane; Reddy, Nagabushana; Renard, Patricia; Raes, Martine; Arnould, Thierry

2014-01-01

Mitochondrial dysfunction(s) (MDs) can be defined as alterations in the mitochondria, including mitochondrial uncoupling, mitochondrial depolarization, inhibition of the mitochondrial respiratory chain, mitochondrial network fragmentation, mitochondrial or nuclear DNA mutations and the mitochondrial accumulation of protein aggregates. All these MDs are known to alter the capacity of ATP production and are observed in several pathological states/diseases, including cancer, obesity, muscle and neurological disorders. The induction of MDs can also alter the secretion of several metabolites, reactive oxygen species production and modify several cell-signalling pathways to resolve the mitochondrial dysfunction or ultimately trigger cell death. Many metabolites, such as fatty acids and derived compounds, could be secreted into the blood stream by cells suffering from mitochondrial alterations. In this review, we summarize how a mitochondrial uncoupling can modify metabolites, the signalling pathways and transcription factors involved in this process. We describe how to identify the causes or consequences of mitochondrial dysfunction using metabolomics (liquid and gas chromatography associated with mass spectrometry analysis, NMR spectroscopy) in the obesity and insulin resistance thematic. PMID:25257998

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Wildcat Creek, Howard County, Indiana

USGS Publications Warehouse

Crawford, Charles G.; Wilber, William G.; Peters, James G.

1979-01-01

The Indiana State Board of Health is developing a water-quality management plan that includes establishing limits for wastewater effluents discharged into Indiana streams. A digital model calibrated to conditions in Wildcat Creek was used to predict alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that benthic-oxygen demand is the most significant factor affecting the dissolved-oxygen concentrations in Wildcat Creek during summer low flows. The Indiana stream dissolved-oxygen standard should not be violated if the Kokomo wastewater-treatment facility meets its current National Pollution Discharge Elimination System permit restrictions (average monthly 5-day biochemical-oxygen demand of 5 milligrams per liter and maximum weekly 5-day biochemical-oxygen demand of 7.5 milligrams per liter) and benthic-oxygen demand becomes negligible. Ammonia-nitrogen toxicity may also be a water-quality limitation in Wildcat Creek. Ammonia-nitrogen waste loads for the Kokomo wastewater-treatment facility, projected by the Indiana State Board of Health, will result in stream ammonia-nitrogen concentrations that exceed the State standard (2.5 milligrams per liter during summer months and 4.0 milligrams per liter during winter months). (Kosco-USGS)

Large-eddy simulation of oxygen transport and depletion in waterbodies

NASA Astrophysics Data System (ADS)

Scalo, Carlo; Piomelli, Ugo; Boegman, Leon

2010-11-01

Dissolved oxygen (DO) in water plays an important role in lake and marine ecosystems. Agricultural runoff may spur excessive plant growth on the water surface; when the plants die they sink to the bottom of the water bodies and decompose, consuming oxygen. Significant environmental (and economic) damage may result from the loss of aquatic life caused by the oxygen depletion. The study of DO transport and depletion dynamics in water bodies has, therefore, become increasingly important. We study this phenomenon by large-eddy simulations performed at laboratory scale. The equations governing the transport of momentum and of a scalar (the DO) in the fluid are coupled to a biochemical model for DO depletion in the permeable sediment bed [Higashino et al., Water Res. (38) 1, 2004)], and to an equation for the fluid transpiration in the porous medium. The simulations are in good agreement with previous calculations and experiments. We show that the results are sensitive to the biochemical and fluid dynamical properties of the sediment, which are very difficult to determine experimentally.

A MEMS approach to determine the biochemical oxygen demand (BOD) of wastewaters

NASA Astrophysics Data System (ADS)

Recoules, L.; Migaou, A.; Dollat, X.; Thouand, G.; Gue, A. M.; Boukabache, A.

2017-07-01

A MEMS approach to obtain an efficient tool for the evaluation of the biochemical oxygen demand (BOD) of wastewaters is introduced. Its operating principle is based on the measurement of oxygen concentration in water samples containing organic pollutants and specific bacteria. The microsystem has been designed to perform multiple and parallel measurements in a poly-wells microfluidic device. The monitoring of the bacterial activity is ensured by optical sensors incorporated in each well of the fluidic network. By using an optode sensor, it is hereby demonstrated that this approach is efficient to measure organic pollutants by testing different Luria Bertani buffer dilutions. These results also show that it is possible to reduce the duration of measurements from 5 d (BOD5) of the standard approach to few hours, typically 3 h-5 h.

Effect Of Organic Substrate Composition On Microbial Community Structure Of Pilot-Scale Biochemical Reactors Treating Mining Influenced Water

EPA Science Inventory

Mining-influenced water (MIW) is acidic, metal rich water formed when sulfide minerals react with oxygen and water. There are various options for the treatment of MIW; however, passive biological systems such as biochemical reactors (BCRs) have shown promise because of their low...

Effect Of Organic Substrate Composition On Microbial Community Structure Of Pilot-Scale Biochemical Reactors Treating Mining Influenced Water - (Presentation)

EPA Science Inventory

Mining-influenced water (MIW) is acidic, metal rich water formed when sulfide minerals react with oxygen and water. There are various options for the treatment of MIW; however, passive biological systems such as biochemical reactors (BCRs) have shown promise because of their low...

Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

PubMed Central

2011-01-01

Background Reactive oxygen species (ROS) are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2) accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are discussed. PMID:21481232

ASTROCULTURE (TM) root metabolism and cytochemical analysis

NASA Technical Reports Server (NTRS)

Porterfield, D. M.; Barta, D. J.; Ming, D. W.; Morrow, R. C.; Musgrave, M. E.

2000-01-01

Physiology of the root system is dependent upon oxygen availability and tissue respiration. During hypoxia nutrient and water acquisition may be inhibited, thus affecting the overall biochemical and physiological status of the plant. For the Astroculture (TM) plant growth hardware, the availability of oxygen in the root zone was measured by examining the changes in alcohol dehydrogenase (ADH) activity within the root tissue. ADH activity is a sensitive biochemical indicator of hypoxic conditions in plants and was measured in both spaceflight and control roots. In addition to the biochemical enzyme assays, localization of ADH in the root tissue was examined cytochemically. The results of these analyses showed that ADH activity increased significantly as a result of spaceflight exposure. Enzyme activity increased 248% to 304% in dwarf wheat when compared with the ground controls and Brassica showed increases between 334% and 579% when compared with day zero controls. Cytochemical staining revealed no differences in ADH tissue localization in any of the dwarf wheat treatments. These results show the importance of considering root system oxygenation in designing and building nutrient delivery hardware for spaceflight plant cultivation and confirm previous reports of an ADH response associated with spaceflight exposure.

Integrating water quality responses to best management practices in Portugal.

PubMed

Fonseca, André; Boaventura, Rui A R; Vilar, Vítor J P

2018-01-01

Nutrient nonpoint pollution has a significant impact on water resources worldwide. The main challenge of this work was to assess the application of best management practices in agricultural land to comply with water quality legislation for surface waters. The Hydrological Simulation Program-FORTRAN was used to evaluate water quality of Ave River in Portugal. Best management practices (infiltration basin) (BMP) were applied to agricultural land (for 3, 6, 9, 12, and 15% area) with removal efficiencies of 50% for fecal coliforms and 30% for nitrogen, phosphorus, and biochemical oxygen demand. The inflow of water quality constituents was reduced for all scenarios, with fecal coliforms achieving the highest reduction between 5.8 and 28.9% and nutrients and biochemical oxygen demand between 2 and 13%. Biochemical oxygen demand and orthophosphates concentrations achieved a good water quality status according to the European Legislation for scenarios of BMP applied to 3 and 12% agricultural area, respectively. Fecal coliform levels in Ave River basin require further treatment to fall below the established value in the abovementioned legislation. This study shows that agricultural watersheds such as Ave basins demand special attention in regard to nonpoint pollution sources effects on water quality and nutrient loads.

LIPOMICS, AN IMPORTANT COMPONENT OF METABOLOMICS, AND POSSIBLE USE IN TOXICOLOGY STUDIES

EPA Science Inventory

Metabolites of endogenous biochemical substances can be considered to represent the ultimate organ and cellular responses to toxicants or other changes in an organism's environment. An important fraction of these endogenously produced metabolites are lipids; the comprehensive stu...

Oxygen in wound healing: nutrient, antibiotic, signaling molecule, and therapeutic agent.

PubMed

Eisenbud, David E

2012-07-01

Disturbances to healing observed under hypoxic conditions have given insights into the roles of oxygen. Wound hypoxia is more prevalent than generally appreciated, and occurs even in patients who are free of arterial occlusive disease. There is a strong scientific basis for oxygen treatment as prophylaxis against infection, to facilitate wound closure, and to prevent amputation in wounded patients. This article reviews extensive data from preclinical and human trials of supplemental inhaled oxygen, hyperbaric oxygen, and topical oxygen treatment. Oxygen supports biochemical metabolism and cellular function, and has roles in combating infection and facilitating the wound healing cascade. Copyright © 2012 Elsevier Inc. All rights reserved.

Photodynamic therapy potentiates the paracrine endothelial stimulation by colorectal cancer

NASA Astrophysics Data System (ADS)

Lamberti, María Julia; Florencia Pansa, María; Emanuel Vera, Renzo; Belén Rumie Vittar, Natalia; Rivarola, Viviana Alicia

2014-11-01

Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer death worldwide. Recurrence is a major problem and is often the ultimate cause of death. In this context, the tumor microenvironment influences tumor progression and is considered as a new essential feature that clearly impacts on treatment outcome, and must therefore be taken into consideration. Photodynamic therapy (PDT), oxygen, light and drug-dependent, is a novel treatment modality when CRC patients are inoperable. Tumor vasculature and parenchyma cells are both potential targets of PDT damage modulating tumor-stroma interactions. In biological activity assessment in photodynamic research, three-dimensional (3D) cultures are essential to integrate biomechanical, biochemical, and biophysical properties that better predict the outcome of oxygen- and drug-dependent medical therapies. Therefore, the objective of this study was to investigate the antitumor effect of methyl 5-aminolevulinic acid-PDT using a light emitting diode for the treatment of CRC cells in a scenario that mimics targeted tissue complexity, providing a potential bridge for the gap between 2D cultures and animal models. Since photodynamic intervention of the tumor microenvironment can effectively modulate the tumor-stroma interaction, it was proposed to characterize the endothelial response to CRC paracrine communication, if one of these two populations is photosensitized. In conclusion, we demonstrated that the dialogue between endothelial and tumor populations when subjected to lethal PDT conditions induces an increase in angiogenic phenotype, and we think that it should be carefully considered for the development of PDT therapeutic protocols.

Technical, hygiene, economic, and life cycle assessment of full-scale moving bed biofilm reactors for wastewater treatment in India.

PubMed

Singh, Anju; Kamble, Sheetal Jaisingh; Sawant, Megha; Chakravarthy, Yogita; Kazmi, Absar; Aymerich, Enrique; Starkl, Markus; Ghangrekar, Makarand; Philip, Ligy

2018-01-01

Moving bed biofilm reactor (MBBR) is a highly effective biological treatment process applied to treat both urban and industrial wastewaters in developing countries. The present study investigated the technical performance of ten full-scale MBBR systems located across India. The biochemical oxygen demand, chemical oxygen demand, total suspended solid, pathogens, and nutrient removal efficiencies were low as compared to the values claimed in literature. Plant 1 was considered for evaluation of environmental impacts using life cycle assessment approach. CML 2 baseline 2000 methodology was adopted, in which 11 impact categories were considered. The life cycle impact assessment results revealed that the main environmental hot spot of this system was energy consumption. Additionally, two scenarios were compared: scenario 1 (direct discharge of treated effluent, i.e., no reuse) and scenario 2 (effluent reuse and tap water replacement). The results showed that scenario 2 significantly reduce the environmental impact in all the categories ultimately decreasing the environmental burden. Moreover, significant economic and environmental benefits can be obtained in scenario 2 by replacing the freshwater demand for non-potable uses. To enhance the performance of wastewater treatment plant (WWTP), there is a need to optimize energy consumption and increase wastewater collection efficiency to maximize the operating capacity of plant and minimize overall environmental footprint. It was concluded that MBBR can be a good alternative for upgrading and optimizing existing municipal wastewater treatment plants with appropriate tertiary treatment. Graphical abstract ᅟ.

Water Quality: A Field-Based Quality Testing Program for Middle Schools and High Schools.

ERIC Educational Resources Information Center

Massachusetts State Water Resources Authority, Boston.

This manual contains background information, lesson ideas, procedures, data collection and reporting forms, suggestions for interpreting results, and extension activities to complement a water quality field testing program. Information on testing water temperature, water pH, dissolved oxygen content, biochemical oxygen demand, nitrates, total…

Biochemical upgrading of oils

DOEpatents

Premuzic, Eugene T.; Lin, Mow S.

1999-01-12

A process for biochemical conversion of heavy crude oils is provided. The process includes contacting heavy crude oils with adapted biocatalysts. The resulting upgraded oil shows, a relative increase in saturated hydrocarbons, emulsions and oxygenates and a decrease in compounds containing in organic sulfur, organic nitrogen and trace metals. Adapted microorganisms which have been modified under challenged growth processes are also disclosed.

Biochemical upgrading of oils

DOEpatents

Premuzic, E.T.; Lin, M.S.

1999-01-12

A process for biochemical conversion of heavy crude oils is provided. The process includes contacting heavy crude oils with adapted biocatalysts. The resulting upgraded oil shows, a relative increase in saturated hydrocarbons, emulsions and oxygenates and a decrease in compounds containing organic sulfur, organic nitrogen and trace metals. Adapted microorganisms which have been modified under challenged growth processes are also disclosed. 121 figs.

Biopower generation from kitchen wastewater using a bioreactor.

PubMed

Khan, Abdul M; Naz, Shamsa

2014-01-01

This research provides a comparative study of the power output from mediator-less and mediator microbial fuel cells (MFCs) under aerobic and partially anaerobic conditions using kitchen wastewater (KWW) as a renewable energy source. The wastewater sample was subjected to different physical, chemical, biochemical, and microbial analysis. The chemical oxygen demand (COD), biochemical oxygen demand (BOD), and power output values were greater for the fermented samples than the non-fermented samples. The power output of samples was compared through the development of MFCs by using sand-salt bridge and agar-salt bridge. The H2 that was produced was converted to atomic hydrogen by using the nickel-coated zinc electrode. In addition, the power output was further enhanced by introducing air into the cathodic chamber, where oxygen reacts with the protons to form pure H2O. The study showed that the power output was increased with the increase in COD and BOD values.

Development of a biochemical oxygen demand sensor using gold-modified boron doped diamond electrodes.

PubMed

Ivandini, Tribidasari A; Saepudin, Endang; Wardah, Habibah; Harmesa; Dewangga, Netra; Einaga, Yasuaki

2012-11-20

Gold-modified boron doped diamond (BDD) electrodes were examined for the amperometric detection of oxygen as well as a detector for measuring biochemical oxygen demand (BOD) using Rhodotorula mucilaginosa UICC Y-181. An optimum potential of -0.5 V (vs Ag/AgCl) was applied, and the optimum waiting time was observed to be 20 min. A linear calibration curve for oxygen reduction was achieved with a sensitivity of 1.4 μA mg(-1) L oxygen. Furthermore, a linear calibration curve in the glucose concentration range of 0.1-0.5 mM (equivalent to 10-50 mg L(-1) BOD) was obtained with an estimated detection limit of 4 mg L(-1) BOD. Excellent reproducibility of the BOD sensor was shown with an RSD of 0.9%. Moreover, the BOD sensor showed good tolerance against the presence of copper ions up to a maximum concentration of 0.80 μM (equivalent to 50 ppb). The sensor was applied to BOD measurements of the water from a lake at the University of Indonesia in Jakarta, Indonesia, with results comparable to those made using a standard method for BOD measurement.

Protein Tyrosine Nitration: Role in Aging.

PubMed

Chakravarti, Bulbul; Chakravarti, Deb N

2017-01-01

Aging is the inevitable fate of all living organisms, but the molecular basis of physiological aging is poorly understood. Oxidative stress is believed to play a key role in the aging process. In addition to Reactive Oxygen Species (ROS), Reactive Nitrogen Species (RNS) are generated during aerobic metabolism in living organisms. Although protein damage and functional modification by ROS have been demonstrated in details, fewer studies have been reported on protein damage by RNS and its implication in the aging process. Proteins undergoing tyrosine nitration are associated with pathophysiology of several diseases, as well as physiological aging. The purpose of the current review article is to provide a brief summary of the biochemical mechanisms of tyrosine nitration, methodologies used for the detection of these modified proteins, effect of RNS induced post translational modification on biological functions and the putative role of tyrosine nitrated proteins in the aging process. Published studies on the role of RNS in age related functional alteration of various organs/ tissues were critically reviewed and evaluated. Covalent modification of various proteins by tyrosine nitration is associated with modification of biological functions of various organs/tissues such as skeletal muscle, heart, brain and liver due to aging. This information will be helpful to further investigate the interplay of different biochemical pathways and networks involved in the tyrosine nitration of various proteins due to aging with the ultimate goal to prevent the detrimental effects of RNS on the functional activities of these proteins. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Quality of water and time-of-travel in Bakers Creek near Clinton, Mississippi. [Bakers Creek

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalkhoff, S.J.

1982-01-01

A short-term intensive quality-of-water study was conducted during a period of generally low streamflow in Bakers Creek and its tributary, Lindsey Creek, near Clinton, Mississippi. During the September 15-18, 1980 study, dissolved oxygen concentrations in Bakers Creek were less than 5 milligrams per liter. The specific conductance, 5-day biochemical oxygen demand, nutrient concentrations, and bacteria densities in Bakers Creek decreased downstream through the study reach. The mean specific conductance decreased from 670 to 306 microhms per centimeter. The 5-day biochemical oxygen demand decreased from 19 to 2.8 milligrams per liter. The mean total nitrogen and phosphorous concentrations decreased from 10more » and 7.1 to 1.0 and 0.87 milligram per litter, respectively. The maximum fecal bacteria decreased from 7200 to 400 colonies per 100 milliliter. The concentrations of mercury, iron, and manganese in a sample collected at the downstream site exceeded recommended limits. Diazinon and 2,4-D were also present in the water. A bottom material sample contained DDD (2.5 micrograms per kilogram), DDE (2.7 micrograms per kilogram), and DDT (.3 micrograms per kilogram). The tributary inflow from Lindsey Creek did not improve the water quality of Bakers Creek. The dissolved oxygen concentrations were generally less than 5.0 milligrams per liter at the sampling site on Lindsey Creek. The 5-day biochemical oxygen demand, the mean specific conductance, and fecal coliform densities were greater in the tributary than at the downstream site on Bakers Creek. The average rate of travel through a 1.8-mile reach of Bakers Creek was 0.06 foot per second or 0.04 miles per hour. 6 references, 9 figures, 2 tables.« less

Dissolved oxygen and aeration in ictalurid catfish aquaculture

USDA-ARS?s Scientific Manuscript database

Feed-based production of ictalurid catfish in ponds is the largest aquaculture sector in the United States. The feed biochemical oxygen demand (FBOD) typically is 1.1-1.2 kg O2/kg feed. Feed also results in a substantial increase of carbon dioxide, ammonia nitrogen, and phosphate to ponds, and this ...

Spectral Analysis; Applications in Water Pollution Control.

ERIC Educational Resources Information Center

Wastler, T. A.

The statistical technique of analyzing data collected at regular intervals to reveal periodic components of the data is described by reference to actual records. The data chosen for illustration include tide height in a river; biochemical oxygen demand and dissolved oxygen in the same river; discharged salt into a river system and its relation to…

Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

NASA Technical Reports Server (NTRS)

Baldwin, R.; Pham, M.; Leonida, A.; Mcelroy, J.; Nalette, T.

1989-01-01

Hydrogen-oxygen solid polymer electrolyte (SPE) fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. These solid electrolyte devices have been under continuous development for over 30 years. This experience has resulted in a demonstrated ten-year SPE cell life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluoride loss rates and average expected ultimate cell life. This relationship is shown. Several features have been introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability has been demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density.

Characterization of human cervical remodeling throughout pregnancy using in vivo Raman spectroscopy

NASA Astrophysics Data System (ADS)

O'Brien, Christine M.; Vargis, Elizabeth; Slaughter, Chris; Rudin, Amy P.; Herington, Jennifer L.; Bennett, Kelly A.; Reese, Jeff; Mahadevan-Jansen, Anita

2015-02-01

Globally, fifteen million babies are born preterm each year, affecting 1 in 8 pregnancies in the US alone. Cervical remodeling includes a biochemical cascade of changes that ultimately result in the thinning and dilation of the cervix for passage of a fetus. This process is poorly understood and is the focus of this study. Our group is utilizing Raman spectroscopy to evaluate biochemical changes occurring in the human cervix throughout pregnancy. This technique has high molecular specificity and can be performed in vivo, with the potential to unveil new molecular dynamics essential for cervical remodeling.

Toxicity, Mutagenesis and Aging due to Endogenous Oxygen Radicals.

DTIC Science & Technology

1984-12-21

Fridovich, Investigations of the state of the -- manganese in Lactobacillus plantarum . Arch. Biochem. Biophys. 215, 589- 596 (1982). DiGuiseppi, J., and...4, 101-112 (1983). * Kono, Y., and I. Fridovich, Isolation and characterization of the * . pseudocatalase of Lactobacillus plantarum : a new manganese...Arch. Biochem. Biophys. 225, 640-648 (1983). Kono, Y., and I. Fridovich, The functional significance of manganese catalase in Lactobacillus plantarum

Microbial and chemical properties of log ponds along the Oregon Coast.

Treesearch

Iwan Ho; Ching Yan Li

1987-01-01

The microbial and chemical properties of log ponds along the Oregon coast were investigated. The log ponds were highly eutrophic, containing high concentrations of ammonium and nitrate nitrogen, phosphate, and organic compounds. Because of large microbial populations, the biochemical oxygen demand was high and dissolved oxygen was low. Bacterial species in log ponds...

75 FR 39735 - Mandatory Reporting of Greenhouse Gases From Magnesium Production, Underground Coal Mines...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-12

... Available Monitoring Methods BOD 5 5-day biochemical oxygen demand CAA Clean Air Act CBI confidential... carbon dioxide CO 2 e CO 2 -equivalent COD chemical oxygen demand DOC Degradable organic carbon EIA... of ventilation systems by the Mine Safety and Health Administration (MSHA) are subject to 40 CFR part...

Singlet oxygen in the coupled photochemical and biochemical oxidation of dissolved organic matter.

PubMed

Cory, Rose M; McNeill, Kristopher; Cotner, James P; Amado, Andre; Purcell, Jeremiah M; Marshall, Alan G

2010-05-15

Dissolved organic matter (DOM) is a significant (>700 Pg) global C pool. Transport of terrestrial DOM to the inland waters and coastal zones represents the largest flux of reduced C from land to water (215 Tg yr(-1)) (Meybeck, M. Am. J. Sci. 1983, 282, 401-450). Oxidation of DOM by interdependent photochemical and biochemical processes largely controls the fate of DOM entering surface waters. Reactive oxygen species (ROS) have been hypothesized to play a significant role in the photooxidation of DOM, because they may oxidize the fraction of DOM that is inaccessible to direct photochemical degradation by sunlight. We followed the effects of photochemically produced singlet oxygen ((1)O(2)) on DOM by mass spectrometry with (18)O-labeled oxygen, to understand how (1)O(2)-mediated transformations of DOM may lead to altered DOM bioavailability. The photochemical oxygen uptake by DOM attributed to (1)O(2) increased with DOM concentration, yet it remained a minority contributor to photochemical oxygen uptake even at very high DOM concentrations. When DOM samples were exposed to (1)O(2)-generating conditions (Rose Bengal and visible light), increases were observed in DOM constituents with higher oxygen content and release of H(2)O(2) was detected. Differential effects of H(2)O(2) and (1)O(2)-treated DOM showed that (1)O(2)-treated DOM led to slower bacterial growth rates relative to unmodified DOM. Results of this study suggested that the net effect of the reactions between singlet oxygen and DOM may be production of partially oxidized substrates with correspondingly lower potential biological energy yield.

Biochemical establishment and characterization of EncM's flavin-N5-oxide cofactor

PubMed Central

Teufel, Robin; Stull, Frederick; Meehan, Michael J.; Michaudel, Quentin; Dorrestein, Pieter C.; Palfey, Bruce; Moore, Bradley S.

2016-01-01

The ubiquitous flavin-dependent monooxygenases commonly catalyze oxygenation reactions by means of a transient C4a-peroxyflavin. A recent study, however, suggested an unprecedented flavin-oxygenating species - proposed as the flavin-N5-oxide (FlN5[O]) - as key to an oxidative Favorskii-type rearrangement in the biosynthesis of the bacterial polyketide antibiotic enterocin. This stable superoxidized flavin is covalently tethered to the enzyme EncM and converted into FADH2 (Flred) during substrate turnover. Subsequent reaction of Flred with molecular oxygen restores the postulated FlN5[O] via an unknown pathway. Here we provide direct evidence for the FlN5[O] species via isotope labeling, proteolytic digestion, and high-resolution tandem mass spectrometry of EncM. We propose that formation of this species occurs by hydrogen-transfer from Flred to molecular oxygen, allowing radical coupling of the formed protonated superoxide and anionic flavin semiquinone at N5, before elimination of water affords the FlN5[O] cofactor. Further biochemical and spectroscopic investigations reveal important features of the FlN5[O] species and the EncM catalytic mechanism. We speculate that flavin-N5-oxides may be intermediates or catalytically active species in other flavoproteins that form the anionic semiquinone and promote access of oxygen to N5. PMID:26067765

Oxygen sensing and signaling.

PubMed

van Dongen, Joost T; Licausi, Francesco

2015-01-01

Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway.

Water-quality assessment and wastewater-management alternatives for Dardenne Creek in St Charles County, Missouri

USGS Publications Warehouse

Berkas, W.R.; Lodderhose, J.R.

1985-01-01

The quality of water in the 15 mile downstream reach of Dardenne Creek in St. Charles County, Missouri, was assessed to determine if it met the Missouri water quality standards. Concentrations of dissolved oxygen and total ammonia failed to meet water quality standards downstream from the Harvester-Dardenne and St. Peters Wastewater-Treatment Plants. The QUAL-II SEMCOG water quality model was calibrated and verified using two independent data sets from Dardenne Creek. Management alternatives using current, design capacity, and future expansion wastewater discharges from the St. Peters Wastewater-Treatment Plant were evaluated. Results of the computer simulation indicate that a nitrification-type advanced-treatment facility installed at the plant would produce a 5-day carbonaceous biochemical oxygen demand of 10 mg/L. An effluent limit of 5.0 mg/L of 5-day carbonaceous biochemical oxygen demand would further improve the water quality of Dardenne Creek; however, an additional treatment process, such as sand filtration, would be needed to meet this criterion. (USGS)

Water quality in the Sugar Creek basin, Bloomington and Normal, Illinois

USGS Publications Warehouse

Prugh, Byron J.

1978-01-01

Urban runoff and overflows from combined sewers affect water quantity and quality in Sugar Creek within the twin cities of Bloomington and Normal, Illinois. Water-quality data from five primary and eight secondary locations showed three basic types of responses to climatic and hydrologic stresses. Stream temperatures and concentrations of dissolved oxygen, ammonia nitrogen, total phosphorus, biochemical oxygen demand, and fecal bacteria showed seasonal variations. Specific conductivity, pH, chloride, and suspended solids concentrations varied more closely with stream discharges. Total organic carbon, total nitrogen, total phosphorus, biochemical oxygen demand, and fecal coliform and fecal streptococcal bacteria concentrations exhibited variations indicative of intial flushing action during storm runoff. Selected analyses for herbicides, insecticides, and other complex organic compounds in solution and in bed material showed that these constituents were coming from sources other than the municipal sanitary treatment plant effluent. Analyses for 10 common metals: arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, and zinc showed changes in concentrations below the municipal sanitary plant outfall. (Woodard-USGS)

Effects of Al3+ and La3+ trivalent metal ions on tomato fruit proteomes

USDA-ARS?s Scientific Manuscript database

The tomato (Solanum lycopersicum) ripening process from mature green (MG) to turning and then to red stages is accompanied by the occurrences of physiological and biochemical reactions, which ultimately result in the formation of the flavor, color and texture of ripe fruits. The two trivalent metal ...

Environmental Assessment Addressing the Integrated Control of Nuisance Species at Grand Forks Air Force Base, North Dakota

DTIC Science & Technology

2013-04-01

different non-target invertebrates (GFAFB 2003e). A study examining the non-target effects of Bti on stream invertebrate communities and fish (Lacy and...Factor), BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), EC50 (50% effect concentration), ED 50 (50% effect dose), I.M. (intramuscular...loss of oxygen may cause fish suffocation. Therefore, treat only 1/3 to 1/2 of the water body area at one time and wait 14 days between treatments

Recent Insights into the Cell Biology of Thyroid Angiofollicular Units

PubMed Central

Denef, Jean-François; Lengelé, Benoit; Many, Marie-Christine; Gérard, Anne-Catherine

2013-01-01

In thyrocytes, cell polarity is of crucial importance for proper thyroid function. Many intrinsic mechanisms of self-regulation control how the key players involved in thyroid hormone (TH) biosynthesis interact in apical microvilli, so that hazardous biochemical processes may occur without detriment to the cell. In some pathological conditions, this enzymatic complex is disrupted, with some components abnormally activated into the cytoplasm, which can lead to further morphological and functional breakdown. When iodine intake is altered, autoregulatory mechanisms outside the thyrocytes are activated. They involve adjacent capillaries that, together with thyrocytes, form the angiofollicular units (AFUs) that can be considered as the functional and morphological units of the thyroid. In response to iodine shortage, a rapid expansion of the microvasculature occurs, which, in addition to nutrients and oxygen, optimizes iodide supply. These changes are triggered by angiogenic signals released from thyrocytes via a reactive oxygen species/hypoxia-inducible factor/vascular endothelial growth factor pathway. When intra- and extrathyrocyte autoregulation fails, other forms of adaptation arise, such as euthyroid goiters. From onset, goiters are morphologically and functionally heterogeneous due to the polyclonal nature of the cells, with nodules distributed around areas of quiescent AFUs containing globules of compact thyroglobulin (Tg) and surrounded by a hypotrophic microvasculature. Upon TSH stimulation, quiescent AFUs are activated with Tg globules undergoing fragmentation into soluble Tg, proteins involved in TH biosynthesis being expressed and the local microvascular network extending. Over time and depending on physiological needs, AFUs may undergo repetitive phases of high, moderate, or low cell and tissue activity, which may ultimately culminate in multinodular goiters. PMID:23349248

Hazardous Waste Minimization Assessment: Fort Carson, CO

DTIC Science & Technology

1991-01-01

microorganisms ( bacteria , fungi, etc.) to decompose and/or bioaccumulate the contaminants in wastes. As a HAZMIN technique, treatment, unlike source...Water is analyzed for fecal coliform bacteria , residual chlorine, 5-day biochemical oxygen demand (BOD5), suspended solids (SS), chemical oxygen demand...manufacturer Kinsbursky Bros. Supply (714) 738-8516 North Lemon Street Recycler, Spent batteries X Anaheim, CA 92801 Lubrication Co. of America (213

Watershed modeling of dissolved oxygen and biochemical oxygen demand using a hydrological simulation Fortran program.

PubMed

Liu, Zhijun; Kieffer, Janna M; Kingery, William L; Huddleston, David H; Hossain, Faisal

2007-11-01

Several inland water bodies in the St. Louis Bay watershed have been identified as being potentially impaired due to low level of dissolved oxygen (DO). In order to calculate the total maximum daily loads (TMDL), a standard watershed model supported by U.S. Environmental Protection Agency, Hydrological Simulation Program Fortran (HSPF), was used to simulate water temperature, DO, and bio-chemical oxygen demand (BOD). Both point and non-point sources of BOD were included in watershed modeling. The developed model was calibrated at two time periods: 1978 to 1986 and 2000 to 2001 with simulated DO closely matched the observed data and captured the seasonal variations. The model represented the general trend and average condition of observed BOD. Water temperature and BOD decay are the major factors that affect DO simulation, whereas nutrient processes, including nitrification, denitrification, and phytoplankton cycle, have slight impacts. The calibrated water quality model provides a representative linkage between the sources of BOD and in-stream DO\\BOD concentrations. The developed input parameters in this research could be extended to similar coastal watersheds for TMDL determination and Best Management Practice (BMP) evaluation.

Attenuation of Scattered Thermal Energy Atomic Oxygen

NASA Technical Reports Server (NTRS)

Banks, Bruce a.; Seroka, Katelyn T.; McPhate, Jason B.; Miller, Sharon K.

2011-01-01

The attenuation of scattered thermal energy atomic oxygen is relevant to the potential damage that can occur within a spacecraft which sweeps through atomic oxygen in low Earth orbit (LEO). Although there can be significant oxidation and resulting degradation of polymers and some metals on the external surfaces of spacecraft, there are often openings on a spacecraft such as telescope apertures, vents, and microwave cavities that can allow atomic oxygen to enter and scatter internally to the spacecraft. Atomic oxygen that enters a spacecraft can thermally accommodate and scatter to ultimately react or recombine on surfaces. The atomic oxygen that does enter a spacecraft can be scavenged by use of high erosion yield polymers to reduce its reaction on critical surfaces and materials. Polyoxymethylene and polyethylene can be used as effective atomic oxygen scavenging polymers.

Effects of advanced treatment of municipal wastewater on the White River near Indianapolis, Indiana; trends in water quality, 1978-86

USGS Publications Warehouse

Crawford, Charles G.; Wangsness, David J.

1993-01-01

The City of Indianapolis has constructed state-of-the-art advanced municipal wastewater-treatment systems to enlarge and upgrade the existing secondary-treatment processes at its Belmont and Southport treatment plants. These new advanced-wastewater-treatment plants became operational in 1983. A nonparametric statistical procedure--a modified form of the Wilcoxon-Mann-Whitney rank-sum test--was used to test for trends in time-series water-quality data from four sites on the White River and from the Belmont and Southport wastewater-treatment plants. Time-series data representative of pre-advanced- (1978-1980) and post-advanced- (1983--86) wastewater-treatment conditions were tested for trends, and the results indicate substantial changes in water quality of treated effluent and of the White River downstream from Indianapolis after implementation of advanced wastewater treatment. Water quality from 1981 through 1982 was highly variable due to plant construction. Therefore, this time period was excluded from the analysis. Water quality at sample sites located upstream from the wastewater-treatment plants was relatively constant during the period of study (1978-86). Analysis of data from the two plants and downstream from the plants indicates statistically significant decreasing trends in effluent concentrations of total ammonia, 5-day biochemical-oxygen demand, fecal-coliform bacteria, total phosphate, and total solids at all sites where sufficient data were available for testing. Because of in-plant nitrification, increases in nitrate concentration were statistically significant in the two plants and in the White River. The decrease in ammonia concentrations and 5-day biochemical-oxygen demand in the White River resulted in a statistically significant increasing trend in dissolved-oxygen concentration in the river because of reduced oxygen demand for nitrification and biochemical oxidation processes. Following implementation of advanced wastewater treatment, the number of river-quality samples that failed to meet the water-quality standards for ammonia and dissolved oxygen that apply to the White River decreased substantially.

40 CFR 405.41 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Butter Subcategory § 405.41 Specialized... term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into process. It...

The Evolution of the Earliest Cells.

ERIC Educational Resources Information Center

Schopf, J. William

1978-01-01

Describes the unicellular microorganisms of three billion years ago. Explains how these primitive cells gave rise to biochemical systems and the present oxygen-rich atmosphere. Numerous diagrams, charts, and illustrations. (MA)

Modelling (18)O2 and (16)O2 unidirectional fluxes in plants. III: fitting of experimental data by a simple model.

PubMed

André, Marcel J

2013-08-01

Photosynthetic assimilation of CO2 in plants results in the balance between the photochemical energy developed by light in chloroplasts, and the consumption of that energy by the oxygenation processes, mainly the photorespiration in C3 plants. The analysis of classical biological models shows the difficulties to bring to fore the oxygenation rate due to the photorespiration pathway. As for other parameters, the most important key point is the estimation of the electron transport rate (ETR or J), i.e. the flux of biochemical energy, which is shared between the reductive and oxidative cycles of carbon. The only reliable method to quantify the linear electron flux responsible for the production of reductive energy is to directly measure the O2 evolution by (18)O2 labelling and mass spectrometry. The hypothesis that the respective rates of reductive and oxidative cycles of carbon are only determined by the kinetic parameters of Rubisco, the respective concentrations of CO2 and O2 at the Rubisco site and the available electron transport rate, ultimately leads to propose new expressions of biochemical model equations. The modelling of (18)O2 and (16)O2 unidirectional fluxes in plants shows that a simple model can fit the photosynthetic and photorespiration exchanges for a wide range of environmental conditions. Its originality is to express the carboxylation and the oxygenation as a function of external gas concentrations, by the definition of a plant specificity factor Sp that mimics the internal reactions of Rubisco in plants. The difference between the specificity factors of plant (Sp) and of Rubisco (Sr) is directly related to the conductance values to CO2 transfer between the atmosphere and the Rubisco site. This clearly illustrates that the values and the variation of conductance are much more important, in higher C3 plants, than the small variations of the Rubisco specificity factor. The simple model systematically expresses the reciprocal variations of carboxylation and oxygenation exchanges illustrated by a "mirror effect". It explains the protective sink effect of photorespiration, e.g. during water stress. The importance of the CO2 compensation point, in classical models, is reduced at the benefit of the crossing points Cx and Ox, concentration values where carboxylation and oxygenation are equal or where the gross O2 uptake is half of the gross O2 evolution. This concept is useful to illustrate the feedback effects of photorespiration in the atmosphere regulation. The constancy of Sp and of Cx for a great variation of P under several irradiance levels shows that the regulation of the conductance maintains constant the internal CO2 and the ratio of photorespiration to photosynthesis (PR/P). The maintenance of the ratio PR/P, in conditions of which PR could be reduced and the carboxylation increased, reinforces the hypothesis of a positive role of photorespiration and its involvement in the plant-atmosphere co-evolution. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A novel open-type biosensor for the in-situ monitoring of biochemical oxygen demand in an aerobic environment

PubMed Central

Yamashita, Takahiro; Ookawa, Natsuki; Ishida, Mitsuyoshi; Kanamori, Hiroyuki; Sasaki, Harumi; Katayose, Yuichi; Yokoyama, Hiroshi

2016-01-01

Biochemical oxygen demand (BOD) is a widely used index of water-quality assessment. Since bioelectrochemical BOD biosensors require anaerobic conditions for anodic reactions, they are not directly used in aerobic environments such as aeration tanks. Normally, the BOD biosensors are closed-type, where the anode is packed inside a closed chamber to avoid exposure to oxygen. In this study, a novel bioelectrochemical open-type biosensor was designed for in-situ monitoring of BOD during intermittent aeration. The open-type anode, without any protection against exposure to oxygen, was directly inserted into an intermittently aerated tank filled with livestock wastewater. Anodic potential was controlled using a potentiostat. Interestingly, this novel biosensor generated similar levels of current under both aerating and non-aerating conditions, and showed a logarithmic correlation (R2 > 0.9) of current with BOD concentrations up to 250 mg/L. Suspended solids in the wastewater attached to and covered the whole anode, presumably leading to the production of anaerobic conditions inside the covered anode via biological oxygen removal. Exoelectrogenic anaerobes (Geobacter spp.) were detected inside the covered anode using the 16S-rRNA gene. This biosensor will have various practical applications, such as the automatic control of aeration intensity and the in-situ monitoring of natural water environments. PMID:27917947

Polythiophene-fullerene based photodetectors: tuning of spectral response and application in photoluminescence based (bio)chemical sensors.

PubMed

Nalwa, Kanwar S; Cai, Yuankun; Thoeming, Aaron L; Shinar, Joseph; Shinar, Ruth; Chaudhary, Sumit

2010-10-01

A photoluminescence (PL)-based oxygen and glucose sensor utilizing inorganic or organic light emitting diode as the light source, and polythiophene: fullerene type bulk-heterojunction devices as photodetectors, for both intensity and decay-time based monitoring of the sensing element's PL. The sensing element is based on the oxygen-sensitive dye Pt-octaethylporphyrin embedded in a polystyrene matrix.

The Nitrogen Cycle Before the Rise of Oxygen

NASA Astrophysics Data System (ADS)

Ward, L. M.; Hemp, J.; Fischer, W. W.

2016-12-01

The nitrogen cycle on Earth today is driven by a complex network of microbially-mediated transformations. Atmospheric N2 is fixed into biologically available forms that can either be incorporated into biomass or utilized for bioenergetic redox reactions. The cycle is kept in balance by the return of fixed nitrogen to the atmospheric N2 pool by anammox and denitrification. The early evolution and history of the nitrogen cycle is not well resolved, particularly before the evolution of oxygenic photosynthesis and rise of atmospheric oxygen ca. 2.3 Gya. Ammonia oxidation is a biochemically difficult reaction requiring activation of ammonia using O2 or oxidized nitrogen species that are produced using O2. Before the rise of oxygen, when O2 was largely unavailable, nitrification could not proceed, trapping fixed nitrogen in reduced forms such as ammonia and biomass. Without production of nitrite and nitrate, anammox and denitrification could not occur, preventing return of fixed nitrogen to the N2 pool and leaving the nitrogen cycle unclosed. While it has been hypothesized that ammonia oxidation could be driven anaerobically by processes such as phototrophy or iron reduction, these metabolisms have not been recovered in extant microorganisms, and would require complex unknown biochemical mechanisms. Furthermore, phylogenetic data for the key organisms and biochemical pathways involved in denitrification and anammox suggest that these metabolisms postdate the rise of oxygen. This is particularly clear for steps utilizing enzymes in the Heme-Copper Oxidoreductase superfamily, which appear to have originally evolved for O2 reduction at non-negligible substrate concentrations. Together, this suggests that the Archean nitrogen cycle was not closed, and that nitrogen fixed to reduced forms—either through biological nitrogen fixation or abiotic processes—was not easily returned to the atmospheric N2 pool. In principle, this could have stripped the atmosphere of N2 over timescales of hundreds of Myr, which is consistent with recent paleopressure estimates that suggest < 0.5 bar by late Archean time. The modern, N2-rich atmosphere and (largely) closed biological nitrogen cycle may therefore not have evolved until Proterozoic time, after the rise of oxygen.

Steroids, triterpenoids and molecular oxygen

PubMed Central

Summons, Roger E; Bradley, Alexander S; Jahnke, Linda L; Waldbauer, Jacob R

2006-01-01

There is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. Thus, the detection of steroid and triterpenoid hydrocarbons far back in Earth history has been used to infer the antiquity of oxygenic photosynthesis. This prompts the question: were these compounds produced similarly in the past? In this paper, we address this question with a review of the current state of knowledge surrounding the oxygen requirement for steroid biosynthesis and phylogenetic patterns in the distribution of steroid and triterpenoid biosynthetic pathways. The hopanoid and steroid biosynthetic pathways are very highly conserved within the bacterial and eukaryotic domains, respectively. Bacteriohopanepolyols are produced by a wide range of bacteria, and are methylated in significant abundance at the C2 position by oxygen-producing cyanobacteria. On the other hand, sterol biosynthesis is sparsely distributed in distantly related bacterial taxa and the pathways do not produce the wide range of products that characterize eukaryotes. In particular, evidence for sterol biosynthesis by cyanobacteria appears flawed. Our experiments show that cyanobacterial cultures are easily contaminated by sterol-producing rust fungi, which can be eliminated by treatment with cycloheximide affording sterol-free samples. Sterols are ubiquitous features of eukaryotic membranes, and it appears likely that the initial steps in sterol biosynthesis were present in their modern form in the last common ancestor of eukaryotes. Eleven molecules of O2 are required by four enzymes to produce one molecule of cholesterol. Thermodynamic arguments, optimization of function and parsimony all indicate that an ancestral anaerobic pathway is highly unlikely. The known geological record of molecular fossils, especially steranes and triterpanes, is notable for the limited number of structural motifs that have been observed. With a few exceptions, the carbon skeletons are the same as those found in the lipids of extant organisms and no demonstrably extinct structures have been reported. Furthermore, their patterns of occurrence over billion year time-scales correlate strongly with environments of deposition. Accordingly, biomarkers are excellent indicators of environmental conditions even though the taxonomic affinities of all biomarkers cannot be precisely specified. Biomarkers are ultimately tied to biochemicals with very specific functional properties, and interpretations of the biomarker record will benefit from increased understanding of the biological roles of geologically durable molecules. PMID:16754609

40 CFR 63.6620 - What performance tests and other procedures must I use?

Code of Federal Regulations, 2011 CFR

2011-07-01

... based on the ratio of oxygen volume to the ultimate CO2 volume produced by the fuel at zero percent... volume of CO2 produced to the gross calorific value of the fuel from Method 19, dsm3/J (dscf/106 Btu... equivalent percent carbon dioxide (CO2). If pollutant concentrations are to be corrected to 15 percent oxygen...

40 CFR 63.6620 - What performance tests and other procedures must I use?

Code of Federal Regulations, 2012 CFR

2012-07-01

... based on the ratio of oxygen volume to the ultimate CO2 volume produced by the fuel at zero percent... volume of CO2 produced to the gross calorific value of the fuel from Method 19, dsm3/J (dscf/106 Btu... equivalent percent carbon dioxide (CO2). If pollutant concentrations are to be corrected to 15 percent oxygen...

40 CFR 405.11 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Receiving Stations Subcategory § 405.11... subpart. (b) The term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into...

40 CFR 405.31 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Cultured Products Subcategory § 405.31 Specialized... term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into process. It...

40 CFR 405.91 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.91 Specialized... term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into process. It...

40 CFR 405.21 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Fluid Products Subcategory § 405.21 Specialized... term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into process. It...

Structure and function of isozymes: Evolutionary aspects and role of oxygen in eucaryotic organisms

NASA Technical Reports Server (NTRS)

Satyanarayana, T.

1985-01-01

Oxygen is not only one of the most abundant elements on the Earth, but it is also one of the most important elements for life. In terms of composition, the feature of the atmosphere that most distinguishes Earth from other planets is the presence of abundant amounts of oxygen. The first forms of life may have been similar to present day anaerobic bacteria such as clostridium. The relationship between prokaryotes and eukaryotes, if any, has been a topic of much speculation. With only a few exceptions eukaryotes are oxygen-utilizing organisms. This research eukaryotes or eukaryotic biochemical processes requiring oxygen, could have arisen quite early in evolution and utilized the small quantities of photocatalytically produced oxygen which are thought to have been present on the Earth prior to the evolution of massive amounts of photosynthetically-produced oxygen.

Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

NASA Technical Reports Server (NTRS)

Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

2007-01-01

Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

40 CFR 405.101 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Dry Milk Subcategory § 405.101... subpart. (b) The term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into...

40 CFR 405.61 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Natural and Processed Cheese Subcategory § 405.61... subpart. (b) The term “BOD5 input” shall mean the biochemical oxygen demand of the materials entered into...

Dietary Protection Against Pulmonary Oxygen Poisoning.

DTIC Science & Technology

1980-12-31

hyperoxia produces pathological changes in lung which can be fatal. With an interest in delineating dietary factors which might affect the pulmonary response...by dietary fat type (6,7). This study was conducted to investigate any changes in pulmonary PG synthetic capacity following treatment with diets...at 1 atmosphere in controlled environment chambers (9). In our mc3Rl system oxygen exposure produces discernible pulmonary biochem-cal changes after 24

Evaluation of four structural best management practices for highway runoff in Beaufort and Colleton Counties, South Carolina, 2005–2006

USGS Publications Warehouse

Conlon, Kevin J.; Journey, Celeste A.

2008-01-01

In general, the four BMPs were not successful at significantly reducing fecal bacteria, nutrients, and total organic carbon (including associated properties of biochemical oxygen demand and chemical oxygen demand). Three of the four BMPs significantly lowered oil and grease concentrations before the stormwater discharged from the outlet. Additionally, only one BMP was effective at reducing all total and particulate

Uses of lunar sulfur

NASA Technical Reports Server (NTRS)

Vaniman, D.; Pettit, D.; Heiken, G.

1992-01-01

Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical, and biochemical properties. Although known abundances on the Moon are limited (approximately 0.1 percent in mare soils), sulfur is relatively extractable by heating. Coproduction of sulfur during oxygen extraction from ilmenite-rich mare soils could yield sulfur in masses up to 10 percent of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource.

Journey towards the centre of the earth: plant gravitropism

NASA Technical Reports Server (NTRS)

Swatzell, L. J.; Kiss, J. Z.

2000-01-01

The study of gravitropism dates back about two hundred years, and although significant progress has been made in this field, the central question in gravitropism research is still unanswered. How is a physical stimulus transduced into a biochemical signal which ultimately elicits a response (curvature) in a plant? Simply put, how does a plant 'know' which way is down?.

Biochemical Assessment of Stress in Cardiac Tissue in Response to Weightless Space Travel

NASA Technical Reports Server (NTRS)

Brunton, Laurence L.; Meszaros, J. Gary; Lio, Francisco M.

1997-01-01

The absence of unit gravity may cause physiological changes in the cardiovascular system. For instance, in the absence of Earth's gravity, venous return to the heart may increase due, in pan, to decreased pooling of the blood in the extremities. We hypothesize that this would produce an increase in the heart's work load ultimately resulting in hypertrophy.

Hypoxic Induced Decrease in Oxygen Consumption in Cuttlefish (Sepia officinalis) Is Associated with Minor Increases in Mantle Octopine but No Changes in Markers of Protein Turnover

PubMed Central

Capaz, Juan C.; Tunnah, Louise; MacCormack, Tyson J.; Lamarre, Simon G.; Sykes, Antonio V.; Driedzic, William R.

2017-01-01

The common cuttlefish (Sepia officinalis), a dominant species in the north-east Atlantic ocean and Mediterranean Sea, is potentially subject to hypoxic conditions due to eutrophication of coastal waters and intensive aquaculture. Here we initiate studies on the biochemical response to an anticipated level of hypoxia. Cuttlefish challenged for 1 h at an oxygen level of 50% dissolved oxygen saturation showed a decrease in oxygen consumption of 37% associated with an 85% increase in ventilation rate. Octopine levels were increased to a small but significant level in mantle, whereas there was no change in gill or heart. There were no changes in mantle free glucose or glycogen levels. Similarly, the hypoxic period did not result in changes in HSP70 or polyubiquinated protein levels in mantle, gill, or heart. As such, it appears that although there was a decrease in metabolic rate there was only a minor increase in anaerobic metabolism as evidenced by octopine accumulation and no biochemical changes that are hallmarks of alterations in protein trafficking. Experiments with isolated preparations of mantle, gill, and heart revealed that pharmacological inhibition of protein synthesis could decrease oxygen consumption by 32 to 42% or Na+/K+ ATPase activity by 24 to 54% dependent upon tissue type. We propose that the decrease in whole animal oxygen consumption was potentially the result of controlled decreases in the energy demanding processes of both protein synthesis and Na+/K+ ATPase activity. PMID:28603503

Oxygen regulates molecular mechanisms of cancer progression and metastasis.

PubMed

Gupta, Kartik; Madan, Esha; Sayyid, Muzzammil; Arias-Pulido, Hugo; Moreno, Eduardo; Kuppusamy, Periannan; Gogna, Rajan

2014-03-01

Oxygen is the basic molecule which supports life and it truly is "god's gift to life." Despite its immense importance, research on "oxygen biology" has never received the light of the day and has been limited to physiological and biochemical studies. It seems that in modern day biology, oxygen research is summarized in one word "hypoxia." Scientists have focused on hypoxia-induced transcriptomics and molecular-cellular alterations exclusively in disease models. Interestingly, the potential of oxygen to control the basic principles of biology like homeostatic maintenance, transcription, replication, and protein folding among many others, at the molecular level, has been completely ignored. Here, we present a perspective on the crucial role played by oxygen in regulation of basic biological phenomena. Our conclusion highlights the importance of establishing novel research areas like oxygen biology, as there is great potential in this field for basic science discoveries and clinical benefits to the society.

Maintenance of Mitochondrial Oxygen Homeostasis by Cosubstrate Compensation

PubMed Central

Kueh, Hao Yuan; Niethammer, Philipp; Mitchison, Timothy J.

2013-01-01

Mitochondria maintain a constant rate of aerobic respiration over a wide range of oxygen levels. However, the control strategies underlying oxygen homeostasis are still unclear. Using mathematical modeling, we found that the mitochondrial electron transport chain (ETC) responds to oxygen level changes by undergoing compensatory changes in reduced electron carrier levels. This emergent behavior, which we named cosubstrate compensation (CSC), enables the ETC to maintain homeostasis over a wide of oxygen levels. When performing CSC, our ETC models recapitulated a classic scaling relationship discovered by Chance [Chance B (1965) J. Gen. Physiol. 49:163-165] relating the extent of oxygen homeostasis to the kinetics of mitochondrial electron transport. Analysis of an in silico mitochondrial respiratory system further showed evidence that CSC constitutes the dominant control strategy for mitochondrial oxygen homeostasis during active respiration. Our findings indicate that CSC constitutes a robust control strategy for homeostasis and adaptation in cellular biochemical networks. PMID:23528093

Noninvasive oxygen monitoring techniques.

PubMed

Wahr, J A; Tremper, K K

1995-01-01

As this article demonstrates, tremendous progress has been made in the techniques of oxygen measurement and monitoring over the past 50 years. From the early developments during and after World War II, to the most recent applications of solid state and microprocessor technology today, every patient in a critical care situation will have several continuous measurements of oxygenation applied simultaneously. Information therefore is available readily to alert personnel of acute problems and to guide appropriate therapy. The majority of effort to date has been placed on measuring oxygenation of arterial or venous blood. The next generation of devices will attempt to provide information about living tissue. Unlike the devices monitoring arterial or venous oxygen content, no "gold standards" exist for tissue oxygenation, so calibration will be difficult, as will interpretation of the data provided. The application of these devices ultimately may lead to a much better understanding of how disease (and the treatment of disease) alters the utilization of oxygen by the tissues.

Constructed wetland as a low cost and sustainable solution for wastewater treatment adapted to rural settlements: the Chorfech wastewater treatment pilot plant.

PubMed

Ghrabi, Ahmed; Bousselmi, Latifa; Masi, Fabio; Regelsberger, Martin

2011-01-01

The paper presents the detailed design and some preliminary results obtained from a study regarding a wastewater treatment pilot plant (WWTPP), serving as a multistage constructed wetland (CW) located at the rural settlement of 'Chorfech 24' (Tunisia). The WWTPP implemented at Chorfech 24 is mainly designed as a demonstration of sustainable water management solutions (low-cost wastewater treatment), in order to prove the efficiency of these solutions working under real Tunisian conditions and ultimately allow the further spreading of the demonstrated techniques. The pilot activity also aims to help gain experience with the implemented techniques and to improve them when necessary to be recommended for wide application in rural settlements in Tunisia and similar situations worldwide. The selected WWTPP at Chorfech 24 (rural settlement of 50 houses counting 350 inhabitants) consists of one Imhoff tank for pre-treatment, and three stages in series: as first stage a horizontal subsurface flow CW system, as second stage a subsurface vertical flow CW system, and a third horizontal flow CW. The sludge of the Imhoff tank is treated in a sludge composting bed. The performances of the different components as well as the whole treatment system were presented based on 3 months monitoring. The results shown in this paper are related to carbon, nitrogen and phosphorus removal as well as to reduction of micro-organisms. The mean overall removal rates of the Chorfech WWTPP during the monitored period have been, respectively, equal to 97% for total suspended solids and biochemical oxygen demand (BOD5), 95% for chemical oxygen demand, 71% for total nitrogen and 82% for P-PO4. The removal of E. coli by the whole system is 2.5 log units.

Examination of oxygen release from plants in constructed wetlands in different stages of wetland plant life cycle.

PubMed

Zhang, Jian; Wu, Haiming; Hu, Zhen; Liang, Shuang; Fan, Jinlin

2014-01-01

The quantification of oxygen release by plants in different stages of wetland plant life cycle was made in this study. Results obtained from 1 year measurement in subsurface wetland microcosms demonstrated that oxygen release from Phragmites australis varied from 108.89 to 404.44 mg O₂/m(2)/d during the different periods from budding to dormancy. Plant species, substrate types, and culture solutions had a significant effect on the capacity of oxygen release of wetland plants. Oxygen supply by wetland plants was estimated to potentially support a removal of 300.37 mg COD/m(2)/d or 55.87 mg NH₄-N/m(2)/d. According to oxygen balance analysis, oxygen release by plants could provide 0.43-1.12% of biochemical oxygen demand in typical subsurface-flow constructed wetlands (CWs). This demonstrates that oxygen release of plants may be a potential source for pollutants removal especially in low-loaded CWs. The results make it possible to quantify the role of plants in wastewater purification.

Effects of dilution on dissolved oxygen depletion and microbial populations in the biochemical oxygen demand determination.

PubMed

Seo, Kyo Seong; Chang, Ho Nam; Park, Joong Kon; Choo, Kwang-Ho

2007-09-01

The biochemical oxygen demand (BOD) value is still a key parameter that can determine the level of organics, particularly the content of biodegradable organics in water. In this work, the effects of sample dilution, which should be done inevitably to get appropriate dissolved oxygen (DO) depletion, on the measurement of 5-day BOD (BOD(5)), was investigated with and without seeding using natural and synthetic water. The dilution effects were also evaluated for water samples taken in different seasons such as summer and winter because water temperature can cause a change in the types of microbial species, thus leading to different oxygen depletion profiles during BOD testing. The predation phenomenon between microbial cells was found to be dependent on the inorganic nutrients and carbon sources, showing a change in cell populations according to cell size after 5-day incubation. The dilution of water samples for BOD determination was linked to changes in the environment for microbial growth such as nutrition. The predation phenomenon between microbial cells was more important with less dilution. BOD(5) increased with the specific amount of inorganic nutrient per microbial mass when the natural water was diluted. When seeding was done for synthetic water samples, the seed volume also affected BOD due to the rate of organic uptake by microbes. BOD(5) increased with the specific bacterial population per organic source supplied at the beginning of BOD measurement. For more accurate BOD measurements, specific guidelines on dilution should be established.

Osmotic stress is accompanied by protein glycation in Arabidopsis thaliana.

PubMed

Paudel, Gagan; Bilova, Tatiana; Schmidt, Rico; Greifenhagen, Uta; Berger, Robert; Tarakhovskaya, Elena; Stöckhardt, Stefanie; Balcke, Gerd Ulrich; Humbeck, Klaus; Brandt, Wolfgang; Sinz, Andrea; Vogt, Thomas; Birkemeyer, Claudia; Wessjohann, Ludger; Frolov, Andrej

2016-12-01

Among the environmental alterations accompanying oncoming climate changes, drought is the most important factor influencing crop plant productivity. In plants, water deficit ultimately results in the development of oxidative stress and accumulation of osmolytes (e.g. amino acids and carbohydrates) in all tissues. Up-regulation of sugar biosynthesis in parallel to the increasing overproduction of reactive oxygen species (ROS) might enhance protein glycation, i.e. interaction of carbonyl compounds, reducing sugars and α-dicarbonyls with lysyl and arginyl side-chains yielding early (Amadori and Heyns compounds) and advanced glycation end-products (AGEs). Although the constitutive plant protein glycation patterns were characterized recently, the effects of environmental stress on AGE formation are unknown so far. To fill this gap, we present here a comprehensive in-depth study of the changes in Arabidopsis thaliana advanced glycated proteome related to osmotic stress. A 3 d application of osmotic stress revealed 31 stress-specifically and 12 differentially AGE-modified proteins, representing altogether 56 advanced glycation sites. Based on proteomic and metabolomic results, in combination with biochemical, enzymatic and gene expression analysis, we propose monosaccharide autoxidation as the main stress-related glycation mechanism, and glyoxal as the major glycation agent in plants subjected to drought. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Limnological Monitoring on the Upper Mississippi River System, 1993-1996: Lake City Field Station

DTIC Science & Technology

1999-10-01

Reports of this type provide a synopsis of the collected data and collection methods, as well as a preliminary report of remarkable or unusual conditions ... conditions . To meet this need, Congress authorized a Long Term Resource Monitoring Program (LTRMP) for the Upper Mississippi River System (UMRS). The LTRMP...primarily for human consumption or regulatory purposes (e.g., chemical oxygen demand, biochemical oxygen demand, total coliform bacteria , fecal coliform

Reactive oxygen species generation and signaling in plants

PubMed Central

Tripathy, Baishnab Charan; Oelmüller, Ralf

2012-01-01

The introduction of molecular oxygen into the atmosphere was accompanied by the generation of reactive oxygen species (ROS) as side products of many biochemical reactions. ROS are permanently generated in plastids, peroxisomes, mitochiondria, the cytosol and the apoplast. Imbalance between ROS generation and safe detoxification generates oxidative stress and the accumulating ROS are harmful for the plants. On the other hand, specific ROS function as signaling molecules and activate signal transduction processes in response to various stresses. Here, we summarize the generation of ROS in the different cellular compartments and the signaling processes which are induced by ROS. PMID:23072988

40 CFR 417.181 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.171 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.171 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.181 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.181 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.181 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.171 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.171 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.171 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

40 CFR 417.181 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., page 131. (d) The term BOD7 shall mean the biochemical oxygen demand as determined by incubation at 20 degrees C for a period of 7 days using an acclimated seed. Agitation employing a magnetic stirrer set at...

Effects of joint configuration for the arc welding of cast Ti-6Al-4V alloy rods in argon.

PubMed

Taylor, J C; Hondrum, S O; Prasad, A; Brodersen, C A

1998-03-01

Titanium and its alloys are more commonly used in prosthodontics and welding has become the most common modality for their joining. Studies on the welding of titanium and its alloys have not quantified this value, though its importance has been suggested. This study compared the strength and properties of the joint achieved at various butt joint gaps by the arc-welding of cast Ti-6Al-4V alloy tensile bars in an argon atmosphere. Forty of 50 specimens were sectioned and welded at four gaps. All specimens underwent tensile testing to determine ultimate tensile strength and percentage elongation, then oxygen analysis and scanning electron microscopy. As no more than 3 samples in any group of 10 actually fractured in the weld itself, a secondary analysis that involved fracture location was initiated. There were no differences in ultimate tensile strength or percentage elongation between specimens with weld gaps of 0.25, 0.50, 0.75, and 1.00 mm and the as-cast specimens. There were no differences in ultimate tensile strength between specimens fracturing in the weld and those fracturing in the gauge in welded specimens; however, as-cast specimens demonstrated a higher ultimate tensile strength than welded specimens that fractured in the weld. Specimens that fractured in the weld site demonstrated less ductility than those that fractured in the gauge in both welded and as-cast specimens, as confirmed by scanning electron microscopy examination. The weld wire showed an oxygen scavenging effect from the as-cast parent alloy. The effects of the joint gap were not significant, whereas the characteristics of the joint itself were, which displayed slightly lower strength and significantly lower ductility (and thus decreased toughness). The arc-welding of cast titanium alloy in argon atmosphere appears to be a reliable and efficient prosthodontic laboratory modality producing predictable results, although titanium casting and joining procedures must be closely controlled to minimize heat effects and oxygen contamination.

Mechanism of Rifampicin Inactivation in Nocardia farcinica

PubMed Central

Abdelwahab, Heba; Martin Del Campo, Julia S.; Dai, Yumin; Adly, Camelia; El-Sohaimy, Sohby; Sobrado, Pablo

2016-01-01

A novel mechanism of rifampicin (Rif) resistance has recently been reported in Nocardia farcinica. This new mechanism involves the activity of rifampicin monooxygenase (RifMO), a flavin-dependent monooxygenase that catalyzes the hydroxylation of Rif, which is the first step in the degradation pathway. Recombinant RifMO was overexpressed and purified for biochemical analysis. Kinetic characterization revealed that Rif binding is necessary for effective FAD reduction. RifMO exhibits only a 3-fold coenzyme preference for NADPH over NADH. RifMO catalyzes the incorporation of a single oxygen atom forming an unstable intermediate that eventually is converted to 2′-N-hydroxy-4-oxo-Rif. Stable C4a-hydroperoxyflavin was not detected by rapid kinetics methods, which is consistent with only 30% of the activated oxygen leading to product formation. These findings represent the first reported detailed biochemical characterization of a flavin-monooxygenase involved in antibiotic resistance. PMID:27706151

Investigation of DMSD Trend in the ISS Water Processor Assembly

NASA Technical Reports Server (NTRS)

Carter, Layne; Bowman, Elizabeth; Wilson, Mark; Gentry, Greg; Rector, Tony

2013-01-01

The ISS Water Recovery System (WRS) is responsible for providing potable water to the crew, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. The WRS includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WPA processes condensate from the cabin air and distillate produced by the UPA. In 2010, an increasing trend in the Total Organic Carbon (TOC) in the potable water was ultimately identified as dimethylsilanediol (DMSD). The increasing trend was ultimately reversed after replacing the WPA's two multifiltration beds. However, the reason for the TOC trend and the subsequent recovery was not understood. A subsequent trend occurred in 2012. This paper summarizes the current understanding of the fate of DMSD in the WPA, how the increasing TOC trend occurred, and the plan for modifying the WPA to prevent recurrence.

[Biochemical characteristics of compensation of posthemorrhagic anemia in patients presenting with nasal bleeding].

PubMed

Boĭko, N V; Kolmakova, T S; Bykova, V V

2010-01-01

This work was designed to study the development of compensatory processes during posthemorrhagic anemia in 82 patients presenting with nasal bleeding (NB). The patients were allocated to three groups. Group 1 included patients with isolated episodes of NB, group 2 was comprised of patients in a moderately severe condition with recurring NB, group 3 was composed of patients in a severe condition with recurring NB. The general medical examination was supplemented by the evaluation of factors maintaining the oxygen-transporting function of the blood (hemoglobin affinity for oxygen, erythrocyte content of 2.3-diphosphoglyceric (2.3-DPG) acid as the principal modulator of hemoglobin affinity for oxygen) and indicators of energy (carbohydrate) metabolism in plasma and erythrocytes (glucose-6-phosphate dehydrogenase (G-6-PDH) activity, pyruvic acid (PA), lactate and lactate dehydrogenase (LDH) levels). Changes of biochemical parameters in patients presenting with incidental episodes of NB (group 1) suggested a compensatory increase in functional potential of the blood oxygen-transporting system. Patients of group 2 showed evidence of development of the modulation-type adaptive and compensatory mechanisms. Those of group 3 experienced a decrease of the 2.3-DPH level in erythrocytes and enhancement of hemoglobin affinity for oxygen which slowed down its uptake by the tissues. Tissue hypoxia and accompanying acidosis aggravated the impairment of gas-transporting function of the blood. In is concluded that patients of group 3 are at risk of uncompensated hypoxic hypoxia associated with the unfavourable changes in the oxygen-transporting function and the impairment of the functional potential of erythrocytes. Taken together, these untoward factors may be responsible for the severe clinical conditions of these patients.

Dynamics of biochemical processes and redox conditions in geochemically linked landscapes of oligotrophic bogs

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Szajdak, L.; Sergeeva, M. A.

2016-04-01

The biological activity in oligotrophic peatlands at the margins of the Vasyugan Mire has been studied. It is shown found that differently directed biochemical processes manifest themselves in the entire peat profile down to the underlying mineral substrate. Their activity is highly variable. It is argued that the notion about active and inert layers in peat soils is only applicable for the description of their water regime. The degree of the biochemical activity is specified by the physical soil properties. As a result of the biochemical processes, a micromosaic aerobic-anaerobic medium is developed under the surface waterlogged layer of peat deposits. This layer contains the gas phase, including oxygen. It is concluded that the organic and mineral parts of peat bogs represent a single functional system of a genetic peat profile with a clear record of the history of its development.

Limnological Monitoring on the Upper Mississippi River System, 1993-1996: Long Term Resource Monitoring Program Havana Field Station

DTIC Science & Technology

2002-11-01

synopsis of the collected data and collection methods, as well as a preliminary report of remarkable or unusual conditions in the system. They are intended...resource requires scientific understanding of the ecosystem and of its long-term trends and conditions . To meet this need, Congress authorized a Long...chemical oxygen demand, biochemical oxygen demand, total coliform bacteria , fecal coliform bacteria , fecal streptococcus, heavy metals, pesticides, and

Aspects of Industrial Water Treatment.

DTIC Science & Technology

1978-02-01

Biochemical oxygen demand, Nitrate (as I) Cyanide, total 5- d (DOD 5 ) Nitr$te (a N) Cyanide amenable to i Chealc€l oxygen deuma! (COD)) chlorination...for Industrial ProcessWaters * o s .o. . o , ,,. . . , s o , , , , 26 Is CON~TfNTS (Cont’dI TAMLE (Cont’ d ) 10 Limiting Concentration Ranges...the United States are graphically presented in Figures I and 2. D . Z C O’ M ITUMMS OJT WATM U 1. Untreated feedwater can cause numerous problems in

Effects of rainfalls variability and physical-chemical parameters on enteroviruses in sewage and lagoon in Yopougon, Côte d'Ivoire

NASA Astrophysics Data System (ADS)

Momou, Kouassi Julien; Akoua-Koffi, Chantal; Traoré, Karim Sory; Akré, Djako Sosthène; Dosso, Mireille

2017-07-01

The aim of this study was to assess the variability of the content of nutrients, oxidizable organic and particulate matters in raw sewage and the lagoon on the effect of rainfall. Then evaluate the impact of these changes in the concentration of enteroviruses (EVs) in waters. The sewage samples were collected at nine sampling points along the channel, which flows, into a tropical lagoon in Yopougon. Physical-chemical parameters (5-day Biochemical Oxygen Demand, Chemical Oxygen Demand, Suspended Particulate Matter, Total Phosphorus, Orthophosphate, Total Kjeldahl Nitrogen and Nitrate) as well as the concentration of EV in these waters were determined. The average numbers of EV isolated from the outlet of the channel were 9.06 × 104 PFU 100 ml-1. Consequently, EV was present in 55.55 and 33.33 % of the samples in the 2 brackish lagoon collection sites. The effect of rainfall on viral load at the both sewage and brackish lagoon environments is significant correlate (two-way ANOVA, P < 0.05). Furthermore, in lagoon environment, nutrients (Orthophosphate, Total Phosphorus), 5-day Biochemical Oxygen Demand, Chemical Oxygen Demand and Suspended Particulate Matter were significant correlated with EVs loads ( P < 0.05 by Pearson test). The overall results highlight the problem of sewage discharge into the lagoon and correlation between viral loads and water quality parameters in sewage and lagoon.

Plyometric exercise combined with high-intensity interval training improves metabolic abnormalities in young obese females more so than interval training alone.

PubMed

Racil, Ghazi; Zouhal, Hassane; Elmontassar, Wassim; Ben Abderrahmane, Abderraouf; De Sousa, Maysa Vieira; Chamari, Karim; Amri, Mohamed; Coquart, Jeremy B

2016-01-01

The aim of this study was to compare the effects of 12 weeks of high-intensity interval training (HIIT) with the effects of 12 weeks of plyometric exercise combined with HIIT (P+HIIT) on anthropometric, biochemical, and physical fitness data in young obese females. Sixty-eight participants (age, 16.6 ± 1.3 y; body mass, 82.8 ± 5.0 kg; body fat, 39.4% ± 3.3%; body mass index z score, 2.9 ± 0.4) were assigned to 1 of 3 groups: HIIT (2 blocks per session of 6-8 bouts of 30-s runs at 100% velocity at peak oxygen uptake, with 30-s active recovery between bouts at 50%velocity at peak oxygen uptake (n = 23)); P+HIIT (2 blocks per session of 3 different 15-s plyometric exercises with 15-s passive recoveries, totaling 2 min for each plyometric exercise + the same HIIT program (n = 26)); or control (no exercise (n = 19)). Anthropometric (body mass, body mass index z score, body fat, lean body mass, and waist circumference), biochemical (plasma glucose, insulin, leptin and adiponectin concentrations, leptin/adiponectin ratio, and homeostasis model assessment of insulin resistance (HOMA-IR)), physical fitness (peak oxygen uptake, velocity at peak oxygen uptake, squat jump, and countermovement jump performances), and energy intake data were collected. Both training programs improved the anthropometric, biochemical, and physical fitness variables. However, the P+HIIT program induced greater improvements than did the HIIT program in lean body mass (+3.0% ± 1.7%), plasma glucose and leptin concentrations (-11.0% ± 4.7% and -23.8% ± 5.8%, respectively), plasma leptin/adiponectin ratio (-40.9% ± 10.9%), HOMA-IR (-37.3% ± 6.2%), and squat jump performance (22.2% ± 7.5%). Taken together, these findings suggest that adding plyometric exercises to a HIIT program may be more beneficial than HIIT alone in obese female adolescents.

[The effects of oxygen partial pressure changes on the osteometric markers of the bone tissue in rats].

PubMed

Berezovs'kyĭ, V Ia; Zamors'ka, T M; Ianko, R V

2013-01-01

Our purpose was to investigate the oxygen partial pressure changes on the osteometric and biochemical markers of bone tissue in rats. It was shown that breathing of altered gas mixture did not change the mass, general length, sagittal diameter and density thigh-bones in 12-month Wistar male-rats. The dosed normobaric hypoxia increased the activity of alkaline phosphatase and decreased the activity of tartrate-resistant acid phosphatase. At the same time normobaric hyperoxia with 40 and 90% oxygen conversely decreased the activity of alkaline phosphatase and increased the activity of tartrate-resistant acid phosphatase.

Dietary Carcinogens and Anticarcinogens.

ERIC Educational Resources Information Center

Ames, Bruce N.

1983-01-01

Describes 16 mutagens/carcinogens found in plant food and coffee as well as several anticarcinogens also found in such food. Speculates on relevant biochemical mechanisms, particularly the role of oxygen radicals and their inhibitors in the fat/cancer relationship, promotion, anticarcinogenesis, and aging. (JN)

WATER QUALITY MODELING IN THE RIO CHONE ESTUARY

EPA Science Inventory

Water quality in the Rio Chone Estuary, a seasonally inverse, tropical estuary, in Ecuador was characterized by modeling the distribution of biochemical oxygen demand (BOD) and dissolved inorganic nitrogen (DIN) within the water column. These two variables are modeled using modif...

[Biochemical basis of the single theory of aging. Part II. The cell aerobic status, the hypoxia resistance and proliferation].

PubMed

Kirova, Iu I; Borodulin, V B

2009-01-01

Cells of an organism have different parameters of morphology, metabolism, isoenzyme composition, proliferation and respiration. These differences are derivatives of the cell aerobic status. The primary oxygen acceptors are the "macroscopic" cells (neurons, cardiocytes). In these obligatory aerobic cells oxygen is converted into metabolic water directly by the cytochrome oxidase activity. The secondary oxygen acceptors are the "microscopic" cells (other single-nucleus cells). In these facultative aerobic cells oxygen is converted into hydrogen peroxide. The intracellular labile peroxide pool of oxygen is formed by the oxidase, cytochrome P450, superoxide dismutase, and the mitochondrial cyan-resistance oxidase. The mitochondrial isoenzymes of catalase, glutation peroxidase, and thioredoxin reductase convert hydrogen peroxide into molecular oxygen and form high local oxygen concentration as the major factor for the cytochrome oxidase activity. The hypoxia resistance is increased by the growth of the functional activity of the peroxide-generative and peroxide-mobilizative enzyme systems.

Manipulation of Microenvironment with a Built-in Electrochemical Actuator in Proximity of a Dissolved Oxygen Microsensor

NASA Technical Reports Server (NTRS)

Kim, Chang-Soo; Lee, Cae-Hyang; Fiering, Jason O.; Ufer, Stefan; Scarantino, Charles W.; Nagle, H. Troy; Fiering, Jason O.; Ufer, Stefan; Nagle, H. Troy; Scarantino, Charles W.

2004-01-01

Abstract - Biochemical sensors for continuous monitoring require dependable periodic self- diagnosis with acceptable simplicity to check its functionality during operation. An in situ self- diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electrochemical actuation electrode. With a built- in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments, called the oxygen-saturated or oxygen-depleted phases, can be created by water electrolysis depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton) and the feasibility of the proposed concept is demonstrated in a physiological solution. The sensor responds properly during the oxygen-generating and oxygen- depleting phases. The use of these microenvironments for in situ self-calibration is discussed to achieve functional integration as well as structural integration of the microsensor system.

Fractional Analysis of Escherichia coli O157:H7 by Mass Spectrometry-Based Proteomics

DTIC Science & Technology

2012-10-01

column with the Dionex UltiMate 3000 (Thermo Scientific Dionex , Sunnyvale, CA). The resolved peptides were electrosprayed into a linear ion trap MS... chromatography -tandem mass spectrometry, followed by biochemical pathway mapping using the Kyoto Encyclopedia of Genes and Genomes. The fimbriae-specific subset...15. SUBJECT TERMS 3T3 murine fibroblasts Cell toxicity Liquid chromatography Mass spectrometry LC-MS Ricin Ricinus communis

FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

NASA Astrophysics Data System (ADS)

Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

2010-01-01

Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

Biodegradation of RDX and MNX with Rhodococcus sp. Strain DN22: New Insights into the Degradation Pathway

DTIC Science & Technology

2010-11-15

denitrosation of MNX by DN22 did not involve direct participation of either oxygen or water, but both played major roles in subsequent secondary chemical and... secondary reactions and products distributions would pro- vide new insights into the degradation pathway of RDX and thus help in the development of...not involve direct participation of either oxygen or water, but both played major roles in subsequent secondary chemical and biochemical reactions of

Biochemical and molecular characterization of rice (Oryza sativa L.) roots forming a barrier to radial oxygen loss.

PubMed

Kulichikhin, Konstantin; Yamauchi, Takaki; Watanabe, Kohtaro; Nakazono, Mikio

2014-10-01

The formation of a barrier to radial oxygen (O2 ) loss (ROL) in the root is an important adaptation of plants to root flooding, but the biochemical changes in plant roots where the barrier is formed are unclear. In this study, we analysed metabolic profiles and gene expression profiles in roots of rice (Oryza sativa L.) plants grown under stagnant deoxygenated conditions, which induce suberization in the outer cell layers of the roots and formation of barrier to ROL. Under these conditions, two distinctive biochemical features of the roots were the accumulations of malic acid and very long chain fatty acids (VLCFAs). We also showed that the expressions of some genes encoding plastid-localized enzymes, which convert malic acid to acetyl coenzyme A (AcCoA), were simultaneously up-regulated under stagnant conditions. The expression levels of these genes in specific root tissues isolated by laser microdissection suggested that malic acid is converted to AcCoA predominantly in the plastids in the outer cell layers of rice roots. We propose that the physiological role of malic acid accumulation in rice roots grown under stagnant conditions is to provide a substrate for the biosynthesis of fatty acids, which, in turn, are used in the biosynthesis of suberin. © 2014 John Wiley & Sons Ltd.

An Unprecedented NADPH Domain Conformation in Lysine Monooxygenase NbtG Provides Insights into Uncoupling of Oxygen Consumption from Substrate Hydroxylation

DOE PAGES

Binda, Claudia; Robinson, Reeder M.; Martin del Campo, Julia S.; ...

2015-03-23

N-hydroxylating monooxygenases (NMOs) are involved in the biosynthesis of iron-chelating hydroxamate-containing siderophores that play a role in microbial virulence. These flavoenzymes catalyze the NADPH- and oxygen-dependent hydroxylation of amines, such as those found on the side chains of lysine and ornithine. In this work we report the biochemical and structural characterization of Nocardia farcinica Lys monooxygenase (NbtG), which has similar biochemical properties to mycobacterial homologs. NbtG is also active on D-Lys although it binds L-Lys with a higher affinity. Differently from the ornithine monooxygenases PvdA, SidA and KtzI, NbtG can use both NADH and NADPH and is highly uncoupled, producingmore » more superoxide and hydrogen peroxide than hydroxylated Lys. The crystal structure of NbtG solved at 2.4 Å resolution revealed an unexpected protein conformation with a 30° rotation of the NAD(P)H domain with respect to the FAD domain that precludes binding of the nicotinamide cofactor. This “occluded” structure may explain the biochemical properties of NbtG, specifically with regard to the substantial uncoupling and limited stabilization of the C4a-hydroperoxyflavin intermediate. We discuss the biological implications of these findings.« less

Prostaglandin Actions in Established Insect Cell Lines

USDA-ARS?s Scientific Manuscript database

Prostaglandins (PGs) are oxygenated metabolites of arachidonic acid (AA) and two other C20 polyunsaturated fatty acids that serve as biochemical signals that mediate a wide range of physiological functions in animal cells. For example, PGs influence protein expression in establish insect cell lines ...

Effects of metal contamination in situ on osmoregulation and oxygen consumption in the mudflat fiddler crab Uca rapax (Ocypodidae, Brachyura).

PubMed

Capparelli, Mariana V; Abessa, Denis M; McNamara, John C

2016-01-01

The contamination of estuaries by metals can impose additional stresses on estuarine species, which may exhibit a limited capability to adjust their regulatory processes and maintain physiological homeostasis. The mudflat fiddler crab Uca rapax is a typical estuarine crab, abundant in both pristine and contaminated areas along the Atlantic coast of Brazil. This study evaluates osmotic and ionic regulatory ability and gill Na(+)/K(+)-ATPase activity in different salinities (<0.5, 25 and 60‰ S) and oxygen consumption rates at different temperatures (15, 25 and 35°C) in U. rapax collected from localities along the coast of São Paulo State showing different histories of metal contamination (most contaminated Ilha Diana, Santos>Rio Itapanhaú, Bertioga>Picinguaba, Ubatuba [pristine reference site]). Our findings show that the contamination of U. rapax by metals in situ leads to bioaccumulation and induces biochemical and physiological changes compared to crabs from the pristine locality. U. rapax from the contaminated sites exhibit stronger hyper- and hypo-osmotic regulatory abilities and show greater gill Na(+)/K(+)-ATPase activities than crabs from the pristine site, revealing that the underlying biochemical machinery can maintain systemic physiological processes functioning well. However, oxygen consumption, particularly at elevated temperatures, decreases in crabs showing high bioaccumulation titers but increases in crabs with low/moderate bioaccumulation levels. These data show that U. rapax chronically contaminated in situ exhibits compensatory biochemical and physiological adjustments, and reveal the importance of studies on organisms exposed to metals in situ, particularly estuarine invertebrates subject to frequent changes in natural environmental parameters like salinity and temperature. Copyright © 2016. Published by Elsevier Inc.

Catechin is a phytotoxin and a pro-oxidant secreted from the roots of Centaurea stoebe

PubMed Central

Kaushik, Shail; Biedrzycki, Meredith L; Venkatachalam, Lakshmannan

2010-01-01

When applied to the roots of Arabidopsis thaliana, the phytotoxin (±)-catechin triggers a wave of reactive oxygen species (ROS), leading to a cascade of genome-wide changes in gene expression and, ultimately, death of the root system. Biochemical links describing the root secreted phytotoxin, (±)-catechin, represent one of most well studied systems to describe biochemically based negative plant-plant interactions, but of late have also sparked controversies on phytotoxicity and pro-oxidant behavior of (±)-catechin. The studies originating from two labs1–3 maintained that (±)-catechin is not at all phytotoxic but has strong antioxidant activity. The step-wise experiments performed and the highly correlative results reported in the present study clearly indicate that (±)-catechin indeed is phytotoxic against A. thaliana and Festuca idahoensis. Our results show that catechin dissolved in both organic and aqueous phase inflicts phytotoxic activity against both A. thaliana and F. idahoensis. We show that the deviation in results highlighted by the two labs1–3 could be due to different media conditions and a group effect in catechin treated seedlings. We also determined the presence of catechin in the growth medium of C. stoebe to support the previous studies. One of the largest functional categories observed for catechin-responsive genes corresponded to gene families known to participate in cell death and oxidative stress. Our results showed that (±)-catechin treatment to A. thaliana plants resulted in activation of signature cell death genes such as accelerated cell death (acd2) and constitutively activated cell death 1 (cad1). Further, we confirmed our earlier observation of (±)-catechin induced ROS mediated phytotoxicity in A. thaliana. We also provide evidence that (±)-catechin induced ROS could be aggravated in the presence of divalent transition metals. These observations have significant impact on our understanding regarding catechin phytotoxicity and pro-oxidant activity. Our data also illustrates that precise conditions are needed to evaluate the effect of catechin phytotoxicity. PMID:20505358

Hydrogen peroxide and the evolution of oxygenic photosynthesis

NASA Technical Reports Server (NTRS)

Mckay, C. P.; Hartman, H.

1991-01-01

Possible pathways for the evolution of oxygenic photosynthesis in the early reducing atmosphere of the earth are discussed. It is suggested that the abiotic production of atmospheric oxidants could have provided a mechanism by which locally oxidizing conditions were sustained within spatially confined habitats thus removing the available reductants and forcing photosynthetic organisms to utilize water (rather than ferrous or sulfide ions) as the electron donor. It is argued that atmospheric H2O2 played the key role in inducing oxygenic photosynthesis, because, as peroxide concentrations local environments increased, primitive organisms would not only be faced with a loss of a reductant, but would be also forced to develop a biochemical apparatus (such as catalase) that would protect them against the products of oxygenic photosynthesis. This scenario allows for the early evolution of oxygenic photosynthesis at the time when global conditions were still anaerobic.

Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

NASA Technical Reports Server (NTRS)

Baldwin, R.; Pham, M.; Leonida, A.; Mcelroy, J.; Nalette, T.

1989-01-01

Hydrogen-oxygen SPE fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. The SPE cells have demonstrated a ten year life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton-exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluroride loss rates and average expected ultimate cell life. Several features were introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability were demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density. The SPE electrolyzers have demonstrated the same at 1000 ASF. Many future extraterrestrial applications for fuel cells require that they be self recharged. To translate the proven SPE cell life and stability into a highly reliable extraterrestrial electrical energy storage system, a simplification of supporting equipment is required. Static phase separation, static fluid transport and static thermal control will be most useful in producting required system reliability. Although some 200,000 SPE fuel cell hours were recorded in earth orbit with static fluid phase separation, no SPE electrolyzer has, as yet, operated in space.

Gum and deposit formation from jet-turbine and diesel fuels at 130C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayo, F.R.; Lan, Bosco Y.

1986-01-01

The ultimate objective of this work is to devise an accelerated test to compare rates of soluble gum and deposit formation from jet-turbine and diesel fuels in storage and of hard deposits in engines. This paper describes rates of oxygen absorption and gum formation in air at 130 C. For a single fuel or hydrocarbon, the rate of gum formation is closely proportional to the oxygen absorbed, even when this rate varies with purification and additives. In general, pure hydrocarbons absorb oxygen much faster than the fuels, but the fuels and 2-ethylnaphthalene give more gum for the oxygen absorbed thanmore » the other pure hydrocarbons. Gum has two main sources; one appears to be associated with the chain termination mechanism in oxidation, the other coupling of fuel molecules in the absence of oxygen. Other possibilities are discussed.« less

Evaluation of Stem Cell-Derived Red Blood Cells as a Transfusion Product Using a Novel Animal Model.

PubMed

Shah, Sandeep N; Gelderman, Monique P; Lewis, Emily M A; Farrel, John; Wood, Francine; Strader, Michael Brad; Alayash, Abdu I; Vostal, Jaroslav G

2016-01-01

Reliance on volunteer blood donors can lead to transfusion product shortages, and current liquid storage of red blood cells (RBCs) is associated with biochemical changes over time, known as 'the storage lesion'. Thus, there is a need for alternative sources of transfusable RBCs to supplement conventional blood donations. Extracorporeal production of stem cell-derived RBCs (stemRBCs) is a potential and yet untapped source of fresh, transfusable RBCs. A number of groups have attempted RBC differentiation from CD34+ cells. However, it is still unclear whether these stemRBCs could eventually be effective substitutes for traditional RBCs due to potential differences in oxygen carrying capacity, viability, deformability, and other critical parameters. We have generated ex vivo stemRBCs from primary human cord blood CD34+ cells and compared them to donor-derived RBCs based on a number of in vitro parameters. In vivo, we assessed stemRBC circulation kinetics in an animal model of transfusion and oxygen delivery in a mouse model of exercise performance. Our novel, chronically anemic, SCID mouse model can evaluate the potential of stemRBCs to deliver oxygen to tissues (muscle) under resting and exercise-induced hypoxic conditions. Based on our data, stem cell-derived RBCs have a similar biochemical profile compared to donor-derived RBCs. While certain key differences remain between donor-derived RBCs and stemRBCs, the ability of stemRBCs to deliver oxygen in a living organism provides support for further development as a transfusion product.

A Biochemical-Biophysical Study of Hemoglobins from Woolly Mammoth, Asian Elephant, and Humans†

PubMed Central

Yuan, Yue; Shen, Tong-Jian; Gupta, Priyamvada; Ho, Nancy T.; Simplaceanu, Virgil; Tam, Tsuey Chyi S.; Hofreiter, Michael; Cooper, Alan; Campbell, Kevin L.; Ho, Chien

2011-01-01

This study is aimed at investigating the molecular basis of environmental adaptation of woolly mammoth hemoglobin (Hb) to the harsh thermal conditions of the Pleistocene Ice-ages. To this end, we have carried out a comparative biochemical-biophysical characterization of the structural and functional properties of recombinant hemoglobins (rHb) from woolly mammoth (rHb WM) and Asian elephant (rHb AE) in relation to human hemoglobins Hb A and Hb A2 (a minor component of human Hb). We have obtained oxygen equilibrium curves and calculated O2 affinities, Bohr effects, and the apparent heat of oxygenation (ΔH) in the presence and absence of allosteric effectors [inorganic phosphate and inositol hexaphosphate (IHP)]. Here, we show that the four Hbs exhibit distinct structural properties and respond differently to allosteric effectors. In addition, the apparent heat of oxygenation (ΔH) for rHb WM is less negative than that of rHb AE, especially in phosphate buffer and the presence of IHP, suggesting that the oxygen affinity of mammoth blood was also less sensitive to temperature change. Finally, 1H-NMR spectroscopy data indicates that both α1(β/δ)1 and α1(β/δ)2 interfaces in rHb WM and rHb AE are perturbed, whereas only the α1δ1 interface in Hb A2 is perturbed compared to that in Hb A. The distinct structural and functional features of rHb WM presumably facilitated woolly mammoth survival in the Arctic environment. PMID:21806075

Predicting autism at birth.

PubMed

Steinman, Gary

2013-07-01

The amounts of at least three biochemical factors are more often abnormal in autistic people than neurologically normal ones. They include insulin-like growth factor, anti-myelin basic protein, and serotonin. This may explain why processes initiated in utero which hinder normal neurogenesis, especially myelination, continue after delivery. Quantitation of these parameters may make possible the calculation of an autism index, anticipating at birth which children will ultimately develop overt autism. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Impact of exogenous paraquat on enzyme exudation and biochemical changes of lignin degradation fungi].

PubMed

Zhao, Yunchen; Li, Jianlong; Chen, Yuru; Huang, Haixia; Yu, Zui

2009-08-01

To study the effect of exogenous oxygen, we added water solution of paraquat to 7 d cultures of Coriolus versicolor for the next 148 h. Enzyme exudation and biochemical process were investigated on the addition of paraquat. We found that compared with the control (without paraquat), the addition of 30 micromol/L paraquat stimulated the activity of manganese dependent peroxidase (MnP), lignin peroxidase (LiP), and laccases (Lac) 7, 2.5 and 1.3 times, respectively. Also, addition of paraquat enhanced activity of superoxide dismutase (SOD) and catalase (CAT) in the first 48 h. Impact of paraquat on ligninolytic enzymes was significant than that on antioxidant enzyme. Addition of paraquat enhanced phenolic compounds and formaldehyde of cultures too. And concentration of malondialdehyde was increased in the first 24 h. The results showed that addition of paraquat promoted oxidative stress, but the antioxidant systems of the fungal strain are sufficient to prevent mycelia from oxidative stress. As exogenous oxygen, paraquat might be a useful substrate in degradation of lignocellulose.

A BOD monitoring disposable reactor with alginate-entrapped bacteria.

PubMed

Villalobos, Patricio; Acevedo, Cristian A; Albornoz, Fernando; Sánchez, Elizabeth; Valdés, Erika; Galindo, Raúl; Young, Manuel E

2010-10-01

Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen that is required for the biochemical oxidation of the organic compounds in 5 days. New biosensor-based methods have been conducted for a faster determination of BOD. In this study, a mathematical model to evaluate the feasibility of using a BOD sensor, based on disposable alginate-entrapped bacteria, for monitoring BOD in situ was applied. The model considers the influences of alginate bead size and bacterial concentration. The disposable biosensor can be adapted according to specific requirements depending on the organic load contained in the wastewater. Using Klein and Washausen parameter in a Lineweaver-Burk plot, the glucose diffusivity was calculated in 6.4 × 10(-10) (m2/s) for beads of 1 mm in diameter and slight diffusion restrictions were observed (n = 0.85). Experimental results showed a correlation (p < 0.05) between the respirometric peak and the standard BOD test. The biosensor response was representative of BOD.

Comparative impacts of stormwater runoff on water quality of an urban, a suburban, and a rural stream.

PubMed

Mallin, Michael A; Johnson, Virginia L; Ensign, Scott H

2009-12-01

Water quality data at 12 sites within an urban, a suburban, and a rural stream were collected contemporaneously during four wet and eight dry periods. The urban stream yielded the highest biochemical oxygen demand (BOD), orthophosphate, total suspended sediment (TSS), and surfactant concentrations, while the most rural stream yielded the highest total organic carbon concentrations. Percent watershed development and percent impervious surface coverage were strongly correlated with BOD (biochemical oxygen demand), orthophosphate, and surfactant concentrations but negatively with total organic carbon. Excessive fecal coliform abundance most frequently occurred in the most urbanized catchments. Fecal coliform bacteria, TSS, turbidity, orthophosphate, total phosphorus, and BOD were significantly higher during rain events compared to nonrain periods. Total rainfall preceding sampling was positively correlated with turbidity, TSS, BOD, total phosphorus, and fecal coliform bacteria concentrations. Turbidity and TSS were positively correlated with phosphorus, fecal coliform bacteria, BOD, and chlorophyll a, which argues for better sedimentation controls under all landscape types.

Chemical, biochemical, and environmental fiber sensors III; Proceedings of the Meeting, Boston, MA, Sept. 4, 5, 1991

NASA Astrophysics Data System (ADS)

Lieberman, Robert A.

Various papers on chemical, biochemical, and environmental fiber sensors are presented. Individual topics addressed include: fiber optic pressure sensor for combustion monitoring and control, viologen-based fiber optic oxygen sensors, renewable-reagent fiber optic sensor for ocean pCO2, transition metal complexes as indicators for a fiber optic oxygen sensor, fiber optic pH measurements using azo indicators, simple reversible fiber optic chemical sensors using solvatochromic dyes, totally integrated optical measuring sensors, integrated optic biosensor for environmental monitoring, radiation dosimetry using planar waveguide sensors, optical and piezoelectric analysis of polymer films for chemical sensor characterization, source polarization effects in an optical fiber fluorosensor, lens-type refractometer for on-line chemical analysis, fiber optic hydrocarbon sensor system, chemical sensors for environmental monitoring, optical fibers for liquid-crystal sensing and logic devices, suitability of single-mode fluoride fibers for evanescent-wave sensing, integrated modules for fiber optic sensors, optoelectronic sensors based on narrowband A3B5 alloys, fiber Bragg grating chemical sensor.

Yttria Nanoparticle Reinforced Commercially Pure (CP) Titanium

DTIC Science & Technology

2011-09-01

nanoparticles as well as titanium boride (TiB) reinforcements were produced through gas atomization. After consolidation and extrusion, room temperature...pure FE iron O oxygen Ti titanium TiB titanium boride TYS tensile yield strength UTS ultimate tensile strength wt% weight percent Y2O3

Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide

NASA Technical Reports Server (NTRS)

Coutts, Janelle; Hintze, Paul E.; Muscatello, Anthony C.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.; Bauer, Brint; Parks, Steve

2016-01-01

Oxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50 because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon is capable of recovering all the oxygen from carbon dioxide, and is the only real alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon and the resulting carbon buildup will eventually foul the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating one of the designs.

Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide

NASA Technical Reports Server (NTRS)

Hintze, Paul E.; Muscatello, Anthony C.; Meier, Anne J.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.

2016-01-01

Oxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon is capable of recovering all the oxygen from carbon dioxide, and is the only real alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon and the resulting carbon buildup will eventually foul the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating one of the designs.

Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide

NASA Technical Reports Server (NTRS)

Hintze, Paul E.; Muscatello, Anthony C.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.; Bauer, Brint; Parks, Steve

2016-01-01

Oxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon, is capable of recovering all the oxygen from carbon dioxide, and it is a promising alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon, and the resulting carbon buildup eventually fouls the catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating one of the designs.

Water-quality and ancillary data collected from the Arroyo Colorado near Rio Hondo, Texas, 2006

USGS Publications Warehouse

Roussel, Meghan C.; Canova, Michael G.; Asquith, William H.; Kiesling, Richard L.

2007-01-01

The Arroyo Colorado is in the lower Rio Grande Valley of southern Texas and extends from near Mission, Texas, eastward to the Laguna Madre estuarine and coastal marine system, which separates Padre Island from the Texas mainland. Streamflow in the Arroyo Colorado primarily is sustained by effluent from municipal wastewater-treatment plants along the stream banks. Since 1986, the tidal segment of the Arroyo Colorado from the port of Harlingen to the Laguna Madre has been designated by the State of Texas as an impaired water body because of low dissolved oxygen concentrations. Efforts to develop predictive water-quality models for the tidal segment of the Arroyo Colorado have been hampered by a lack of physical, biological, and biochemical data. Specifically, data on primary algal productivity, nutrient cycling, sediment deposition rates, and the relations between these processes and dissolved oxygen dynamics in the stream have been inadequate to support water-quality modeling efforts. The U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, did a study in 2006 to collect data associated with primary algal productivity, nutrient cycling, and dissolved oxygen dynamics in the tidal segment (2201) of the Arroyo Colorado near Rio Hondo. Specific objectives of the study were to (1) characterize water quality by measuring basic properties; (2) characterize the concentrations of carbon and nutrients, biochemical oxygen demand, total organic carbon, total suspended solids, and volatile suspended solids; (3) measure the seasonal differences of nutrient-dependent algal growth and algal production in the water column; (4) measure oxygen respiration or production rates; and (5) measure rates of sediment deposition.

[Biochemical changes in apoptosis and methods for their determination (review)].

PubMed

Sedláková, A; Kohút, A; Kalina, I

1999-08-01

Apoptosis or programmed cell death is a physiological process which occurs at different biological states as well as at disease process. Morphologically it is characterized by the chromatine condensation and other changes with preserved integrity of plasmatic membrane. The major and most frequently studied biochemical characteristic of apoptosis is a DNA fragmentation. In our paper attention is directed to the early biochemical changes in cell membranes, i.g., the externalization of phosphatidylserine, hydrolysis of sphingomyeline on the ceramide and activation of phospholipases especially phospholipase A2. In one part we described the changes of cysteine proteases (caspases), which play a key role in the execution of apoptosis. These biochemical changes are associated with ceramide signalization of apoptosis. Briefly are presented also some dates about apoptosis induction with reactive oxygen radicals and the role of the arachidonic acid metabolites in this process. We consider the investigation and determination of these changes as important parameters of apoptosis at some diseases, e.g., cancer or degenerative diseases, and of their treatment.

Quality of water in James Creek, Monroe County, Mississippi

USGS Publications Warehouse

Bednar, G.A.

1981-01-01

A short-term quality-of-water study of James Creek near Aberdeen , Mississippi was conducted on November 14-16, 1978, during a period of low streamflow. During the study, the water in the 2.6-mile stream reach was undesireable for many uses. Wastewater inflow immediately upstream of the study area contributed to the dissolved-solids load in James Creek. The specific conductance of the water ranged from 775 to 890 micromhos at the head of the study reach and from 650 to 750 micromhos at the end of the study reach. A substantial biochemical oxygen-demand was evident in James Creek. Five-day biochemical oxygen demand values downstream of a sewage disposal pond outfall ranged from 8.3 to 11 milligrams per liter and dissolved-oxygen concentrations ranged from 0.4 to 4.5 milligrams per liter. Nitrogen and phosphorus compounds and fecal bacteria densities were highest downstream. Total ammonia nitrogen and phosphorus concentrations in the water leaving the study area ranged from 0.29 to 1.4 milligrams per liter and from 0.65 to 1.7 milligrams per liter, respectively. Fecal coliform densities exceeding 50,000 colonies per 100 milliliters of sample were observed in the study area. The median fecal coliform density of the water leaving the study area was 2,800 colonies per 100 milliliters. (USGS)

Method and apparatus for energy efficient self-aeration in chemical, biochemical, and wastewater treatment processes

DOEpatents

Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR

2002-05-28

The present invention is a pulse spilling self-aerator (PSSA) that has the potential to greatly lower the installation, operation, and maintenance cost associated with aerating and mixing aqueous solutions. Currently, large quantities of low-pressure air are required in aeration systems to support many biochemical production processes and wastewater treatment plants. Oxygen is traditionally supplied and mixed by a compressor or blower and a mechanical agitator. These systems have high-energy requirements and high installation and maintenance costs. The PSSA provides a mixing and aeration capability that can increase operational efficiency and reduce overall cost.

Simulated Nitrogen Deposition has Minor Effects on Ecosystem Pools and Fluxes of Energy, Elements, and Biochemicals in a Northern Hardwoods Forest

NASA Astrophysics Data System (ADS)

Talhelm, A. F.; Pregitzer, K. S.; Burton, A. J.; Xia, M.; Zak, D. R.

2017-12-01

The elemental and biochemical composition of plant tissues is an important influence on primary productivity, decomposition, and other aspects of biogeochemistry. Human activity has greatly altered biogeochemical cycles in ecosystems downwind of industrialized regions through atmospheric nitrogen deposition, but most research on these effects focuses on individual elements or steps in biogeochemical cycles. Here, we quantified pools and fluxes of biomass, the four major organic elements (carbon, oxygen, hydrogen, nitrogen), four biochemical fractions (lignin, structural carbohydrates, cell walls, and soluble material), and energy in a mature northern hardwoods forest in Michigan. We sampled the organic and mineral soil, fine and coarse roots, leaf litter, green leaves, and wood for chemical analyses. We then combined these data with previously published and archival information on pools and fluxes within this forest, which included replicated plots receiving either ambient deposition or simulated nitrogen deposition (3 g N m-2 yr-1 for 18 years). Live wood was the largest pool of energy and all elements and biochemical fractions. However, the production of wood, leaf litter, and fine roots represented similar fluxes of carbon, hydrogen, oxygen, cell wall material, and energy, while nitrogen fluxes were dominated by leaf litter and fine roots. Notably, the flux of lignin via fine roots was 70% higher than any other flux. Experimental nitrogen deposition had relatively few significant effects, increasing foliar nitrogen, increasing the concentration of lignin in the soil organic horizon and decreasing pools of all elements and biochemical fractions in the soil organic horizon except nitrogen, lignin, and structural carbohydrates. Overall, we found that differences in tissue chemistry concentrations were important determinants of ecosystem-level pools and fluxes, but that nitrogen deposition had little effect on concentrations, pools, or fluxes in this mature forest. Disclaimer: The views expressed in this poster are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Water quality and processes affecting dissolved oxygen concentrations in the Blackwater River, Canaan Valley, West Virginia

USGS Publications Warehouse

Waldron, M.C.; Wiley, J.B.

1996-01-01

The water quality and environmental processes affecting dissolved oxygen were determined for the Blackwater River in Canaan Valley, West Virginia. Canaan Valley is oval-shaped (14 miles by 5 miles) and is located in the Allegheny Mountains at an average elevation of 3,200 feet above sea level. Tourism, population, and real estate development have increased in the past two decades. Most streams in Canaan Valley are a dilute calcium magnesium bicarbonate-type water. Streamwater typicaly was soft and low in alkalinity and dissolved solids. Maximum values for specific conductance, hardness, alkalinity, and dissolved solids occurred during low-flow periods when streamflow was at or near baseflow. Dissolved oxygen concentrations are most sensitive to processes affecting the rate of reaeration. The reaeration is affected by solubility (atmospheric pressure, water temperature, humidity, and cloud cover) and processes that determine stream turbulence (stream depth, width, velocity, and roughness). In the headwaters, photosynthetic dissolved oxygen production by benthic algae can result in supersaturated dissolved oxygen concentrations. In beaver pools, dissolved oxygen consumption from sediment oxygen demand and carbonaceous biochemical oxygen demand can result in dissolved oxygen deficits.

40 CFR 403.15 - Net/Gross calculation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... pollutants in the intake waters. (2) Credit for generic pollutants such as biochemical oxygen demand (BOD... to obtain credit for intake pollutants must make application to the Control Authority. Upon request... to reflect credit for pollutants in the intake water) if the requirements of paragraph (b) of this...

Demonstration Results of Phytoremediation of Explosives-Contaminated Groundwater Using Constructed Wetlands at the Milan Army Ammunition Plant, Milan, Tennessee Volume I (Phase II Demonstration Results).

DTIC Science & Technology

1998-12-01

influence community respiration, photosynthesis, solubility of dissolved oxygen, redox potential, biochemical reaction rates, and ensuing treatment...Conductivity 15-8 15.1.3.5 Dissolved Oxygen Concentration 15-12 15.1.3.6 Redox Potential 15-14 15.1.3.7 pH 15-16 15.1.3.8 Nutrients and Water Quality 15-19...Average Redox Potential of Wetland Waters From June 17, 6-27 1996, to September 16, 1997 Phytoremediation Demonstration Milan AAP FIGURE NUMBER

Water quality of the tidal Potomac River and Estuary; hydrologic data report supplement, 1979 through 1981 water years

USGS Publications Warehouse

Coupe, R.H.; Webb, W.E.

1984-01-01

This report is a companion report to the U.S. Geological Survey 1979, 1980, and 1981 Hydrologic Data Reports of the tidal Potomac River and Estuary. It contains values of biochemical oxygen demand and specific rate constants, incident light and light attenuation measurements; numbers of phytoplankton, fecal coliform and fecal streptococci, cross-sectional averages from field measurements of dissolved oxygen, pH, specific conductance , and temperature data; and cross-sectional averages of chlorophyll data. Sewage treatment plant loads are also included. (USGS)

Biomass for thermochemical conversion: targets and challenges

PubMed Central

Tanger, Paul; Field, John L.; Jahn, Courtney E.; DeFoort, Morgan W.; Leach, Jan E.

2013-01-01

Bioenergy will be one component of a suite of alternatives to fossil fuels. Effective conversion of biomass to energy will require the careful pairing of advanced conversion technologies with biomass feedstocks optimized for the purpose. Lignocellulosic biomass can be converted to useful energy products via two distinct pathways: enzymatic or thermochemical conversion. The thermochemical pathways are reviewed and potential biotechnology or breeding targets to improve feedstocks for pyrolysis, gasification, and combustion are identified. Biomass traits influencing the effectiveness of the thermochemical process (cell wall composition, mineral and moisture content) differ from those important for enzymatic conversion and so properties are discussed in the language of biologists (biochemical analysis) as well as that of engineers (proximate and ultimate analysis). We discuss the genetic control, potential environmental influence, and consequences of modification of these traits. Improving feedstocks for thermochemical conversion can be accomplished by the optimization of lignin levels, and the reduction of ash and moisture content. We suggest that ultimate analysis and associated properties such as H:C, O:C, and heating value might be more amenable than traditional biochemical analysis to the high-throughput necessary for the phenotyping of large plant populations. Expanding our knowledge of these biomass traits will play a critical role in the utilization of biomass for energy production globally, and add to our understanding of how plants tailor their composition with their environment. PMID:23847629

Managing breathlessness: providing comfort at the end of life.

PubMed

Tice, Martha A

2006-04-01

Dyspnea is a common symptom at the end of life. It occurs as the result of a complex mix of physical, biochemical, and perceptual components. When patients and their healthcare providers focus on the "numbers" related to oxygenation, rather than comfort, the individual's quality of life can suffer.

A study of phycophysiology in controlled environments

NASA Technical Reports Server (NTRS)

Krauss, R. W.

1971-01-01

The primary objective of this research is to obtain fundamental data concerning the growth and metabolism of the unicellular green algae. These organisms are most likely to provide biological oxygen and a food source for space crews. Biochemical conversions, chemical composition, and cell growth and division are discussed. Chlorella sorokiniana is emphasized.

Greater heritability of photosynthesis in maize grown under elevated ozone

USDA-ARS?s Scientific Manuscript database

Tropospheric ozone (O3) pollution is estimated to reduce maize yields up to 10% in the US. O3 causes damage to cellular processes by forming reactive oxygen species that lead to reductions in photosynthetic capacity, accelerated leaf senescence, and ultimately a decrease in reproductive and economic...

Effect of Deep Drying and Torrefaction Temperature on Proximate, Ultimate Composition, and Heating Value of 2-mm Lodgepole Pine (Pinus contorta) Grind

PubMed Central

Tumuluru, Jaya Shankar

2016-01-01

Deep drying and torrefaction compose a thermal pretreatment method where biomass is heated in the temperature range of 150–300 °C in an inert or reduced environment. The process parameters, like torrefaction temperature and residence time, have a significant impact on the proximate, ultimate, and energy properties. In this study, torrefaction experiments were conducted on 2-mm ground lodgepole pine (Pinus contorta) using a thermogravimetric analyzer. Both deep drying and torrefaction temperature (160–270 °C) and time (15–120 min) were selected. Torrefied samples were analyzed for the proximate, ultimate, and higher heating value. The results indicate that moisture content decreases with increases in torrefaction temperature and time, where at 270 °C and 120 min, the moisture content is found to be 1.15% (w.b.). Volatile content in the lodgepole pine decreased from about 80% to about 45%, and ash content increased from 0.77% to about 1.91% at 270 °C and 120 min. The hydrogen, oxygen, and sulfur content decreased to 3%, 28.24%, and 0.01%, whereas the carbon content and higher heating value increased to 68.86% and 23.67 MJ/kg at 270 °C and 120 min. Elemental ratio of hydrogen to carbon and oxygen to carbon (H/C and O/C) calculated at 270 °C and a 120-min residence time were about 0.56 and 0.47. Based on this study, it can be concluded that higher torrefaction temperatures ≥230 °C and residence time ≥15 min influence the proximate, ultimate, and energy properties of ground lodgepole pine. PMID:28952578

In-vitro evaluation of limitations and possibilities for the future use of intracorporeal gas exchangers placed in the upper lobe position.

PubMed

Schumer, Erin; Höffler, Klaus; Kuehn, Christian; Slaughter, Mark; Haverich, Axel; Wiegmann, Bettina

2018-03-01

The lack of donor organs has led to the development of alternative "destination therapies", such as a bio-artificial lung (BA) for end-stage lung disease. Ultimately aiming at a fully implantable BA, general capabilities and limitations of different oxygenators were tested based on the model of BA positioning at the right upper lobe. Three different-sized oxygenators (neonatal, paediatric, and adult) were tested in a mock circulation loop regarding oxygenation and decarboxylation capacities for three respiratory pathologies. Blood flows were imitated by a roller pump, and respiration was imitated by a mechanical ventilator with different FiO 2 applications. Pressure drops across the oxygenators and the integrity of the gas-exchange hollow fibers were analyzed. The neonatal oxygenator proved to be insufficient regarding oxygenation and decarboxylation. Despite elevated pCO 2 levels, the paediatric and adult oxygenators delivered comparable sufficient oxygen levels, but sufficient decarboxylation across the oxygenators was ensured only at flow rates of 0.5 L min. Only the adult oxygenator indicated no significant pressure drops. For all tested conditions, gas-exchange hollow fibers remained intact. This is the first study showing the general feasibility of delivering sufficient levels of gas exchange to an intracorporeal BA via patient's breathing, without damaging gas-exchange hollow fiber membranes.

Improvement of a microbial fuel cell performance as a BOD sensor using respiratory inhibitors.

PubMed

Chang, In Seop; Moon, Hyunsoo; Jang, Jae Kyung; Kim, Byung Hong

2005-03-15

Studies were made to improve the performance of a microbial fuel cell (MFC) as a biochemical oxygen demand (BOD) sensor. The signal from MFCs decreased in the presence of electron acceptors of higher redox potential such as nitrate and oxygen. The addition of azide and cyanide did not change the signal in the absence of the electron acceptors. The respiratory inhibitors eliminated the inhibitory effects of the electron acceptors on the current generation from MFCs. Similar results were obtained using oligotrophic MFCs fed with an environmental sample that contained nitrate. The use of the respiratory inhibitors is therefore recommended for the accurate BOD measurement of environmental samples containing nitrate and/or oxygen with an MFC-type BOD sensor.

Study of behavioral parameters during learning of rats in an operant feeding task and evaluation of biochemical indexes after dietary consumption of the phytoecdysteroid extract.

PubMed

Murtazina, E P; Sidorova, Yu S; Zhuravlev, B V; Mazo, V K; Zorin, S N; Volodin, V V

2014-11-01

Experiments on rats were performed to study the process of operant feeding learning, locomotor activity, oxygen consumption, and concentrations of corticosterone, β-endorphin, and prostaglandin E in blood serum after dietary treatment with the phytoecdysteroid extract. Administration of phytoecdysteroids was followed by the improvement of learning and increase in oxygen consumption and locomotor activity. Locomotor activity and oxygen consumption in the majority of control rats and phytoecdysteroid-treated animals were shown to be interrelated with the total locomotor activity and goal-directed operant behavior, respectively. No significant differences were found in the concentration of hormones in blood serum from animals of the control and treatment groups.

How did life survive Earth's great oxygenation?

PubMed

Fischer, Woodward W; Hemp, James; Valentine, Joan Selverstone

2016-04-01

Life on Earth originated and evolved in anoxic environments. Around 2.4 billion-years-ago, ancestors of Cyanobacteria invented oxygenic photosynthesis, producing substantial amounts of O2 as a byproduct of phototrophic water oxidation. The sudden appearance of O2 would have led to significant oxidative stress due to incompatibilities with core cellular biochemical processes. Here we examine this problem through the lens of Cyanobacteria-the first taxa to observe significant fluxes of intracellular dioxygen. These early oxygenic organisms likely adapted to the oxidative stress by co-opting preexisting systems (exaptation) with fortuitous antioxidant properties. Over time more advanced antioxidant systems evolved, allowing Cyanobacteria to adapt to an aerobic lifestyle and become the most important environmental engineers in Earth history. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biochemical changes related to hypoxia during cerebral aneurysm surgery: combined microdialysis and tissue oxygen monitoring: case report.

PubMed

Hutchinson, P J; Al-Rawi, P G; O'Connell, M T; Gupta, A K; Pickard, J D; Kirkpatrick, P J

2000-01-01

The objective of this study was to monitor brain metabolism on-line during aneurysm surgery, by combining the use of a multiparameter (brain tissue oxygen, brain carbon dioxide, pH, and temperature) sensor with microdialysis (extracellular glucose, lactate, pyruvate, and glutamate). The case illustrates the potential value of these techniques by demonstrating the effects of adverse physiological events on brain metabolism and the ability to assist in both intraoperative and postoperative decision-making. A 41-year-old woman presented with a World Federation of Neurological Surgeons Grade I subarachnoid hemorrhage. Angiography revealed a basilar artery aneurysm that was not amenable to coiling, so the aneurysm was clipped. Before the craniotomy was performed, a multiparameter sensor and a microdialysis catheter were inserted to monitor brain metabolism. During the operation, the brain oxygen level decreased, in relation to biochemical changes, including the reduction of extracellular glucose and pyruvate and the elevation of lactate and glutamate. These changes were reversible. However, when the craniotomy was closed, a second decrease in brain oxygen occurred in association with brain swelling, which immediately prompted a postoperative computed tomographic scan. The scan demonstrated acute hydrocephalus, requiring external ventricular drainage. The patient made a full recovery. The monitoring techniques influenced clinical decision-making in the treatment of this patient. On-line measurement of brain tissue gases and extracellular chemistry has the potential to assist in the perioperative and postoperative management of patients undergoing complex cerebrovascular surgery and to establish the effects of intervention on brain homeostasis.

Fast characterization of solid organic waste content with near infrared spectroscopy in anaerobic digestion.

PubMed

Charnier, Cyrille; Latrille, Eric; Jimenez, Julie; Lemoine, Margaux; Boulet, Jean-Claude; Miroux, Jérémie; Steyer, Jean-Philippe

2017-01-01

The development of anaerobic digestion involves both co-digestion of solid wastes and optimization of the feeding recipe. Within this context, substrate characterisation is an essential issue. Although it is widely used, the biochemical methane potential is not sufficient to optimize the operation of anaerobic digestion plants. Indeed the biochemical composition in carbohydrates, lipids, proteins and the chemical oxygen demand of the inputs are key parameters for the optimisation of process performances. Here we used near infrared spectroscopy as a robust and less-time consuming tool to predict the solid waste content in carbohydrates, lipids and nitrogen, and the chemical oxygen demand. We built a Partial Least Square regression model with 295 samples and validated it with an independent set of 46 samples across a wide range of solid wastes found in anaerobic digestion units. The standard errors of cross-validation were 90mgO 2 ⋅gTS -1 carbohydrates, 2.5∗10 -2 g⋅gTS -1 lipids, 7.2∗10 -3 g⋅gTS -1 nitrogen and 99mgO 2 ⋅gTS -1 chemical oxygen demand. The standard errors of prediction were 53mgO 2 ⋅gTS -1 carbohydrates, 3.2∗10 -2 g⋅gTS -1 lipids, 8.6∗10 -3 g⋅gTS -1 nitrogen and 83mgO 2 ⋅gTS -1 chemical oxygen demand. These results show that near infrared spectroscopy is a new fast and cost-efficient way to characterize solid wastes content and improve their anaerobic digestion monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

Continuous electron stimulated desorption using a ZrO2/Ag permeation membrane

NASA Technical Reports Server (NTRS)

Outlaw, R. A.; Hoflund, Gar B.; Davidson, M. R.

1989-01-01

During the development of an atomic oxygen beam generator for laboratory simulation of the atmospheric conditions in low earth orbit, a new technique for performing electron stimulated desorption (ESD) in a continuous manner has been developed. In this technique, oxygen permeates through an Ag membrane at elevated temperature thereby providing a continuous supply of oxygen atoms to the 1000-A ZrO2 coating at the vacuum interface. ESD then results in a large peak of neutral O2 molecules which ultimately decay into steady-state desorption. The ESD signal is linear with respect to primary beam flux (0.035 O2 molecules per electron at a primary beam energy of 1 keV) but nonlinear with respect to primary beam energy.

Oxidizer Selection for the ISTAR Program (Liquid Oxygen versus Hydrogen Peroxide)

NASA Technical Reports Server (NTRS)

Quinn, Jason Eugene; Koelbl, Mary E. (Technical Monitor)

2002-01-01

This paper discusses a study of two alternate oxidizers, liquid oxygen and hydrogen peroxide, for use in a rocket based combined cycle (RBCC) demonstrator vehicle. The flight vehicle is baselined as an airlaunched self-powered Mach 0.7 to 7 demonstration of an RBCC engine through all or its air breathing propulsion modes. Selection of an alternate oxidizer has the potential to lower overall vehicle size, system complexity/ cost and ultimately the total program risk. This trade study examined the oxidizer selection effects upon the overall vehicle performance, safety and operations. After consideration of all the technical and programmatic details available at this time, 90% hydrogen peroxide was selected over liquid oxygen for use in this program.

Nanophase Iron Oxides as an Ultraviolet Sunscreen for Ancient Photosynthetic Microbes: A Possible Link Between Early Organisms, Banded-Iron Formations, and the Oxygenation of the Atmosphere

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Rothschild, Lynn J.; Rothschild, Lynn J.; Rogoff, Dana A.

2006-01-01

We propose that nanophase iron oxide-bearing materials provided important niches for ancient photosynthetic microbes on the early Earth that ultimately led to the oxygenation of the Earth s atmosphere and the formation of iron oxide deposits. Atmospheric oxygen and ozone attenuate UV radiation on the Earth today providing substantial protection for photosynthetic organisms. With ultraviolet radiation fluxes likely to have been even higher on the early Earth than today, accessing solar radiation was particularly risky for early organisms. Yet, we know that photosynthesis arose then and played a critical role in subsequent evolution. Of primary importance was protection at approx.250-290 nm, where peak nucleic acid (approx.260 nm) and protein (approx.280 nm) absorptions occur. Nanophase ferric oxide/oxyhydroxide minerals absorb, and thus block, the lethal UV radiation, while transmitting light through much of the visible and near-infrared regions of interest to photosynthesis (400 to 1100 nm). Further, they were available in early environments, and are synthesized by many organisms. Based on ferric oxide/oxyhydroxide spectral properties, likely geologic processes, and the results of experiments with the photosynthetic organisms, Euglena sp. and Chlumydomonus reinhardtii, we propose a scenario where photosynthesis, and ultimately the oxygenation of the atmosphere, depended on the protection of early microbes by nanophase ferric oxides/oxyhydroxides. The results of this study are also applicable to other potentially habitable iron-bearing planetary bodies because of the evolutionary pressure to utilize solar radiation when available as an energy source.

Cytotoxicity of Manganese (III) Complex in Human Breast Adenocarcinoma Cell Line Is Mediated by the Generation of Reactive Oxygen Species Followed by Mitochondrial Damage.

PubMed

Al-Anbaky, Qudes; Al-Karakooly, Zeiyad; Kilaparty, Surya P; Agrawal, Megha; Albkuri, Yahya M; RanguMagar, Ambar B; Ghosh, Anindya; Ali, Nawab

2016-11-01

Manganese (Mn) complexes are widely studied because of their important catalytic properties in synthetic and biochemical reactions. A Mn (III) complex of an amidoamine ligand was synthesized using a tetradentate amidoamine ligand. In this study, the Mn (III) complex was evaluated for its biological activity by measuring its cytotoxicity in human breast adenocarcinoma cell line (MCF-7). Cytotoxic effects of the Mn (III) complex were determined using established biomarkers in an attempt to delineate the mechanism of action and the utility of the complex as a potential anticancer drug. The Mn (III) complex induces cell death in a dose- and time-dependent manner as shown by microculture tetrazolium assay, a measure of cytotoxic cell death. Our results demonstrated that cytotoxic effects were significantly increased at higher concentrations of Mn (III) complex and with longer time of treatment. The IC 50 (Inhibitor concentration that results in 50% cell death) value of Mn (III) complex in MCF-7 cells was determined to be 2.5 mmol/L for 24 hours of treatment. In additional experiments, we determined the Mn (III) complex-mediated cell death was due to both apoptotic and nonspecific necrotic cell death mechanisms. This was assessed by ethidium bromide/acridine orange staining and flow cytometry techniques. The Mn (III) complex produced reactive oxygen species (ROS) triggering the expression of manganese superoxide dismutase 1 and ultimately damaging the mitochondrial function as is evident by a decline in mitochondrial membrane potential. Treatment of the cells with free radical scavenger, N, N-dimethylthiourea decreased Mn (III) complex-mediated generation of ROS and attenuated apoptosis. Together, these results suggest that the Mn (III) complex-mediated MCF-7 cell death utilizes combined mechanism involving apoptosis and necrosis perhaps due to the generation of ROS. © The Author(s) 2016.

Detonation nanodiamond introduced into samarium doped ceria electrolyte improving performance of solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Pei, Kai; Li, Hongdong; Zou, Guangtian; Yu, Richeng; Zhao, Haofei; Shen, Xi; Wang, Liying; Song, Yanpeng; Qiu, Dongchao

2017-02-01

A novel electrolyte materials of introducing detonation nanodiamond (DNDs) into samarium doped ceria (SDC) is reported here. 1%wt. DNDs doping SDC (named SDC/ND) can enlarge the electrotyle grain size and change the valence of partial ceria. DNDs provide the widen channel to accelerate the mobility of oxygen ions in electrolyte. Larger grain size means that oxygen ions move easier in electrolyte, it can also reduce the alternating current (AC) impedance spectra of internal grains. The lower valence of partial Ce provides more oxygen vacancies to enhance mobility rate of oxygen ions. Hence all of them enhance the transportation of oxygen ions in SDC/ND electrolyte and the OCV. Ultimately the power density of SOFC can reach 762 mw cm-2 at 800 °C (twice higher than pure SDC, which is 319 mw cm-2 at 800 °C), and it remains high power density in the intermediate temperature (600-800 °C). It is relatively high for the electrolyte supported (300 μm) cells.

Electrochemistry suggests proton access from the exit site to the binuclear center in Paracoccus denitrificans cytochrome c oxidase pathway variants.

PubMed

Meyer, Thomas; Melin, Frédéric; Richter, Oliver-M H; Ludwig, Bernd; Kannt, Aimo; Müller, Hanne; Michel, Hartmut; Hellwig, Petra

2015-02-27

Two different pathways through which protons access cytochrome c oxidase operate during oxygen reduction from the mitochondrial matrix, or the bacterial cytoplasm. Here, we use electrocatalytic current measurements to follow oxygen reduction coupled to proton uptake in cytochrome c oxidase isolated from Paracoccus denitrificans. Wild type enzyme and site-specific variants with defects in both proton uptake pathways (K354M, D124N and K354M/D124N) were immobilized on gold nanoparticles, and oxygen reduction was probed electrochemically in the presence of varying concentrations of Zn(2+) ions, which are known to inhibit both the entry and the exit proton pathways in the enzyme. Our data suggest that under these conditions substrate protons gain access to the oxygen reduction site via the exit pathway. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Oxygen, the lung and the diver: friends and foes?

PubMed

van Ooij, Pieter-Jan A M; Sterk, Peter J; van Hulst, Robert A

2016-12-01

Worldwide, the number of professional and sports divers is increasing. Most of them breathe diving gases with a raised partial pressure of oxygen (P O 2 ). However, if the P O 2 is between 50 and 300 kPa (375-2250 mmHg) (hyperoxia), pathological pulmonary changes can develop, known as pulmonary oxygen toxicity (POT). Although in its acute phase, POT is reversible, it can ultimately lead to non-reversible pathological changes. Therefore, it is important to monitor these divers to prevent them from sustaining irreversible lesions.This review summarises the pulmonary pathophysiological effects when breathing oxygen with a P O 2 of 50-300 kPa (375-2250 mmHg). We describe the role and the limitations of lung function testing in monitoring the onset and development of POT, and discuss new techniques in respiratory medicine as potential markers in the early development of POT in divers. Copyright ©ERS 2016.

Development of biodegradable materials; balancing degradability and performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, J.M.; Allen, A.L.; Dell, P.A.

1993-12-31

The development of biodegradable materials suitable for packaging must take into consideration various performance criteria such as mechanical and barrier properties, as well as rate of biodegradability in given environments. Individual or blended biopolymer films were obtained commercially or blown into film in the laboratory and tested for tensile strength, ultimate elongation and oxygen barrier. These films were then subjected to accelerated marine biodegradation tests as well as simulated marine respirometry. Starch/ethylene vinyl alcohol films exhibited good mechanical and excellent oxygen barrier properties, but were very slow to biodegrade in the simulated and excellent oxygen barrier properties, but were verymore » slow to biodegrade in the simulated marine environment. Polyhydroxyalkanoates had good mechanical properties, average oxygen barrier and good biodegradability. Data indicate that performance and biodegradability of packaging can be tailored to needs by combining individual biopolymers in different proportions in blends and laminates.« less

Ultimate intrinsic-coercivity samarium-cobalt magnet: An Earth-based feasibility study for space-shuttle missions. [containerless melts

NASA Technical Reports Server (NTRS)

Das, D. K.; Kumar, K.; Frost, R. T.; Chang, C. W.

1980-01-01

Techniques for containerless melting and solidification of the samarium-cobalt alloy without excessive oxidation were developed. The rationale for extending these experiments in a weightless environment is also discussed. The effect of oxygen content from 0.15 to 0.63 weight percent and grain size in the range of 2 to 10 micrometers has been examined on arc-plasma-sprayed SmCo5 magnets. Contrary to expectations, the larger grain sizes tended to improve the coercivities. This was attributed to an increase in homogeneity resulting from higher temperature treatments used to produce larger grain size. No significant differences in coercivity were observed on the basis of oxygen content in the range examined. It is expected that more meaningful data on the relationship between oxygen content and coercivity will be seen when the oxygen content can be lowered to less than 0.1 weight percent.

Oxygen supply in aquatic ectotherms: partial pressure and solubility together explain biodiversity and size patterns.

PubMed

Verberk, Wilco C E P; Bilton, David T; Calosi, Piero; Spicer, John I

2011-08-01

Aquatic ectotherms face the continuous challenge of capturing sufficient oxygen from their environment as the diffusion rate of oxygen in water is 3 x 10(5) times lower than in air. Despite the recognized importance of oxygen in shaping aquatic communities, consensus on what drives environmental oxygen availability is lacking. Physiologists emphasize oxygen partial pressure, while ecologists emphasize oxygen solubility, traditionally expressing oxygen in terms of concentrations. To resolve the question of whether partial pressure or solubility limits oxygen supply in nature, we return to first principles and derive an index of oxygen supply from Fick's classic first law of diffusion. This oxygen supply index (OSI) incorporates both partial pressure and solubility. Our OSI successfully explains published patterns in body size and species across environmental clines linked to differences in oxygen partial pressure (altitude, organic pollution) or oxygen solubility (temperature and salinity). Moreover, the OSI was more accurately and consistently related to these ecological patterns than other measures of oxygen (oxygen saturation, dissolved oxygen concentration, biochemical oxygen demand concentrations) and similarly outperformed temperature and altitude, which covaried with these environmental clines. Intriguingly, by incorporating gas diffusion rates, it becomes clear that actually more oxygen is available to an organism in warmer habitats where lower oxygen concentrations would suggest the reverse. Under our model, the observed reductions in aerobic performance in warmer habitats do not arise from lower oxygen concentrations, but instead through organismal oxygen demand exceeding supply. This reappraisal of how organismal thermal physiology and oxygen demands together shape aerobic performance in aquatic ectotherms and the new insight of how these components change with temperature have broad implications for predicting the responses of aquatic communities to ongoing global climate shifts.

[Biochemical and biophysical investigation of liposome action in artificially induced ARDS in rabbit lungs].

PubMed

Petkova, D; Steneva, I; Iordanova, A; Khristova, E; Lalchev, Z

2007-01-01

The aim of this study is to evaluate the application of phospholipid liposomes in HCl--induced RDS in rabbits. Acute respiratory distress syndrome was induced by administration of 0.2 N HCl via intratracheal instillation for 45 min. After induced ARDS animals under artificial lung ventilation were retreated with liposomes for 60 min. Arterial blood gas analysis was performed at 30, 45 and 60 min after liposome application. Untreated animals were ventilated for the same time. Rabbits were killed with thiopental and bronhoalveolar lavage fluid biochemical and biophysical parameters were investigated. HCl- lung injury caused decrease of arterial oxygen pressure/ fraction of inspired oxygen ratio more than 50% compared to the control. We obtained high respiratory acidosis as well. The instillation of liposomes led to reversion of gas exchange at 60 min. after application almost to the control value. In order to characterize the rabbit lung tissue changes after HCl-treatment histological and ultra thin slices were obtained. Electron microscopic preparations demonstrate disappearance of surface active film in treated animals. Application of liposomes led to visualization of osmophilic material forming lamellae in lamellar bodies. On the basis of the results obtained we may assume that it is likely that the liposomes assessed in this study might be used for in vivo improvement of oxygenation in acid aspiration induced ARDS.

Effects of advanced wastewater treatment on the quality of White River, Indiana

USGS Publications Warehouse

Crawford, Charles G.; Wangsness, David J.

1991-01-01

In 1983, the City of Indianapolis, Indiana, completed construction of advanced wastewater treatment (AWT) systems to enlarge and upgrade its existing Belmont Road and Southport Road secondary treatment plants. A nonparametric statistical procedure, a modified form of the Wilcoxon-Mann-Whitney rank-sum test, was used to test for trends in water quality at two upstream and two downstream sites on White River and at the two treatment plants. Results comparing the pre- (1978-1980) and post- (1983-1988) AWT periods show statistically significant improvements in the quality of the treated effluent and of the White River downstream from the plants. Water quality at sites upstream from the city was relatively constant during the period of study. Total ammonia (as N) decreased 14.6 mg/L and BOD5 (five-day biochemical oxygen demand) decreased 10 to 19 mg/L in the two effluents. Total ammonia in the river downstream from the plants decreased 0.8 to 1.9 mg/L and BOD5 decreased 2.3 to 2.5 mg/L. Nitrate (as N) increased 14.5 mg/L in the plant effluents and 2.0 to 2.4 mg/L in the river because of in-plant nitrification. Dissolved oxygen concentration in the river increased about 3 mg/L because of reduced oxygen demand for nitrification and biochemical oxidation processes.

Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event

NASA Astrophysics Data System (ADS)

Planavsky, Noah J.; Asael, Dan; Hofmann, Axel; Reinhard, Christopher T.; Lalonde, Stefan V.; Knudsen, Andrew; Wang, Xiangli; Ossa Ossa, Frantz; Pecoits, Ernesto; Smith, Albertus J. B.; Beukes, Nicolas J.; Bekker, Andrey; Johnson, Thomas M.; Konhauser, Kurt O.; Lyons, Timothy W.; Rouxel, Olivier J.

2014-04-01

The early Earth was characterized by the absence of oxygen in the ocean-atmosphere system, in contrast to the well-oxygenated conditions that prevail today. Atmospheric concentrations first rose to appreciable levels during the Great Oxidation Event, roughly 2.5-2.3 Gyr ago. The evolution of oxygenic photosynthesis is generally accepted to have been the ultimate cause of this rise, but it has proved difficult to constrain the timing of this evolutionary innovation. The oxidation of manganese in the water column requires substantial free oxygen concentrations, and thus any indication that Mn oxides were present in ancient environments would imply that oxygenic photosynthesis was ongoing. Mn oxides are not commonly preserved in ancient rocks, but there is a large fractionation of molybdenum isotopes associated with the sorption of Mo onto the Mn oxides that would be retained. Here we report Mo isotopes from rocks of the Sinqeni Formation, Pongola Supergroup, South Africa. These rocks formed no less than 2.95 Gyr ago in a nearshore setting. The Mo isotopic signature is consistent with interaction with Mn oxides. We therefore infer that oxygen produced through oxygenic photosynthesis began to accumulate in shallow marine settings at least half a billion years before the accumulation of significant levels of atmospheric oxygen.

A Quantitative Study of Oxygen as a Metabolic Regulator

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; LaManna, Joseph C.; Cabrera, Marco E.

1999-01-01

An acute reduction in oxygen (O2) delivery to a tissue is generally associated with a decrease in phosphocreatine, increases in ADP, NADH/NAD, and inorganic phosphate, increased rates of glycolysis and lactate production, and reduced rates of pyruvate and fatty acid oxidation. However, given the complexity of the human bioenergetic system and its components, it is difficult to determine quantitatively how cellular metabolic processes interact to maintain ATP homeostasis during stress (e.g., hypoxia, ischemia, and exercise). Of special interest is the determination of mechanisms relating tissue oxygenation to observed metabolic responses at the tissue, organ, and whole body levels and the quantification of how changes in tissue O2 availability affect the pathways of ATP synthesis and the metabolites that control these pathways. In this study, we extend a previously developed mathematical model of human bioenergetics to provide a physicochemical framework that permits quantitative understanding of O2 as a metabolic regulator. Specifically, the enhancement permits studying the effects of variations in tissue oxygenation and in parameters controlling the rate of cellular respiration on glycolysis, lactate production, and pyruvate oxidation. The whole body is described as a bioenergetic system consisting of metabolically distinct tissue/organ subsystems that exchange materials with the blood. In order to study the dynamic response of each subsystem to stimuli, we solve the ordinary differential equations describing the temporal evolution of metabolite levels, given the initial concentrations. The solver used in the present study is the packaged code LSODE, as implemented in the NASA Lewis kinetics and sensitivity analysis code, LSENS. A major advantage of LSENS is the efficient procedures supporting systematic sensitivity analysis, which provides the basic methods for studying parameter sensitivities (i.e., changes in model behavior due to parameter variation). Sensitivity analysis establishes relationships between model predictions and problem parameters (i.e., initial concentrations, rate coefficients, etc). It helps determine the effects of uncertainties or changes in these input parameters on the predictions, which ultimately are compared with experimental observations in order to validate the model. Sensitivity analysis can identify parameters that must be determined accurately because of their large effect on the model predictions and parameters that need not be known with great precision because they have little or no effect on the solution. This capability may prove to be important in optimizing the design of experiments, thereby reducing the use of animals. This approach can be applied to study the metabolic effects of reduced oxygen delivery to cardiac muscle due to local myocardial ischemia and the effects of acute hypoxia on brain metabolism. Other important applications of sensitivity analysis include identification of quantitatively relevant pathways and biochemical species within an overall mechanism, when examining the effects of a genetic anomaly or pathological state on energetic system components and whole system behavior.

A System Dynamics Approach to Modelling the Degradation of Biochemical Oxygen Demand in A Constructed Wetland Receiving Stormwater Runoff

DTIC Science & Technology

1995-12-01

are often collectively referred to as bacteria or prokaryotes. The eukaryote group consists of plants, animals and protists (algae, fungi and...primary microorganisms important in the treatment of wastewaters are the protists from the eukaryote group, and bacteria, or prokaryotes. Bacteria are

Propiconazole increases reactive oxygen species levels in mouse hepatic cells in culture and in mouse liver by a cytochrome P450 enzyme mediated process

EPA Science Inventory

Propiconazole induces hepatocarcinomas and hepatoadenomas in mice and is a rat liver tumor promoter. Transcriptional, proteomic, metabolomic and biochemical studies of hepatic tissues from mice treated with propiconazole under the conditions of the chronic bioassay indicate that ...

The synergy of permeable pavements and geothermal heat pumps for stormwater treatment and reuse.

PubMed

Tota-Maharaj, K; Scholz, M; Ahmed, T; French, C; Pagaling, E

2010-12-14

The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff.

A reduced-order adaptive neuro-fuzzy inference system model as a software sensor for rapid estimation of five-day biochemical oxygen demand

NASA Astrophysics Data System (ADS)

Noori, Roohollah; Safavi, Salman; Nateghi Shahrokni, Seyyed Afshin

2013-07-01

The five-day biochemical oxygen demand (BOD5) is one of the key parameters in water quality management. In this study, a novel approach, i.e., reduced-order adaptive neuro-fuzzy inference system (ROANFIS) model was developed for rapid estimation of BOD5. In addition, an uncertainty analysis of adaptive neuro-fuzzy inference system (ANFIS) and ROANFIS models was carried out based on Monte-Carlo simulation. Accuracy analysis of ANFIS and ROANFIS models based on both developed discrepancy ratio and threshold statistics revealed that the selected ROANFIS model was superior. Pearson correlation coefficient (R) and root mean square error for the best fitted ROANFIS model were 0.96 and 7.12, respectively. Furthermore, uncertainty analysis of the developed models indicated that the selected ROANFIS had less uncertainty than the ANFIS model and accurately forecasted BOD5 in the Sefidrood River Basin. Besides, the uncertainty analysis also showed that bracketed predictions by 95% confidence bound and d-factor in the testing steps for the selected ROANFIS model were 94% and 0.83, respectively.

Biochemical methane potential of two-phase olive mill solid waste: influence of thermal pretreatment on the process kinetics.

PubMed

Rincón, B; Bujalance, L; Fermoso, F G; Martín, A; Borja, R

2013-07-01

The effect of thermal pretreatment on two-phase olive mill solid waste was evaluated by chemical oxygen demand solubilisation and biochemical methane potential (BMP) tests. Temperatures of 100, 120, 160 and 180°C were applied during 60, 120 and 180 min for each temperature studied. The highest chemical oxygen demand solubilisation after pretreatment (42%) was found for 120 and 180°C during 180 min in both cases. These two conditions were selected for the BMP tests. BMP tests showed two different stages: a first exponential stage and a sigmoidal zone after a lag period. No influence of the pretreatment was observed on the kinetic constant of the first-stage. Clear difference was observed in the maximum methane production rate of the second stage, 76.8 mL CH4/(g VS day) was achieved after pretreatment at 180°C (180 min), value 22% and 40% higher than that obtained for the untreated and pretreated OMSW at 120°C, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Water-quality data for water- and wastewater-treatment plants along the Red River of the North, North Dakota and Minnesota, January through October 2006

USGS Publications Warehouse

Damschen, William C.; Hansel, John A.; Nustad, Rochelle A.

2008-01-01

From January through October 2006, six sets of water-quality samples were collected at 28 sites, which included inflow and outflow from seven major municipal water-treatment plants (14 sites) and influent and effluent samples from seven major municipal wastewater treatment plants (14 sites) along the Red River of the North in North Dakota and Minnesota. Samples were collected in cooperation with the Bureau of Reclamation for use in the development of return-flow boundary conditions in a 2006 water-quality model for the Red River of the North. All samples were analyzed for nutrients and major ions. For one set of effluent samples from each of the wastewater-treatment plants, water was analyzed for Eschirichia coli, fecal coliform, 20-day biochemical oxygen demand, 20-day nitrogenous biochemical oxygen demand, total organic carbon, and dissolved organic carbon. In general, results from the field equipment blank and replicate samples indicate that the overall process of sample collection, processing, and analysis did not introduce substantial contamination and that consistent results were obtained.

Quality of surface water at selected sites in the Suwannee River basin, Florida

USGS Publications Warehouse

Coffin, J.E.

1982-01-01

This report presents the results of analyses of water-quality samples collected from 14 surface-water sites in the Suwannee River basin in Florida from January through December 1980. The analyses of samples collected routinely included: nutrients, total organic carbon, and 5-day biochemical oxygen demand, bimonthly; and trace metals, annually. The array of constituents sampled was expanded in October 1978 at three of the original nine stations to provide quality-of-water information for streams draining an industrial area: Rocky Creek near Belmont, Hunter Creek near Belmont, and Swift Creek at Facil. Data collected at these three sites now include: major chemical constituents, six times per year: radium-226, two times per year; and trace metals, one time per year. These constituents are determined in addition to nutrients, total organic carbon, and bio-chemical oxygen demand which continue to be analyzed six times per year. All results of analyses of the water-quality samples collected from January through December 1980 remained within, or near, previously measured ranges and water-quality fluctuations were similar to those noted from data collected since 1971. (USGS)

Acute effects of dietary glycemic index on antioxidant capacity in nutrient-controlled feeding study

USDA-ARS?s Scientific Manuscript database

Oxidative stress, caused by an imbalance between antioxidant capacity and reactive oxygen species, may be an early event in a metabolic cascade elicited by a high glycemic index (GI) diet, ultimately increasing the risk for cardiovascular disease and diabetes. We conducted a feeding study to evalua...

Water quality of the tidal Potomac River and Estuary: Hydrologic Data Reports supplement, 1979 through 1981 water years

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coupe, R.H. Jr.; Webb, W.E.

1984-01-01

This report is a companion report to the US Geological Survey 1979, 1980, and 1981 Hydrologic Data Reports of the tidal Potomac River and Estuary. The information included in this report contains values of biochemical oxygen demand and specific-rate constants, incident-light and light-attenuation measurements; numbers of phytoplankton, fecal coliform and fecal streptococci; cross-sectional averages from field measurements of dissolved oxygen, pH, specific conductance, and temperature data; and cross-sectional averages of chlorophyll data. Sewage-treatment plant loads are also included. 29 refs., 4 figs., 3 tabs.

High Precision Continuous and Real-Time Measurement of Atmospheric Oxygen Using Cavity Ring-Down Spectroscopy.

NASA Astrophysics Data System (ADS)

Kim-Hak, D.; Hoffnagle, J.; Rella, C.; Sun, M.

2016-12-01

Oxygen is a major and vital component of the Earth atmosphere representing about 21% of its composition. It is consumed or produced through biochemical processes such as combustion, respiration, and photosynthesis. Although atmospheric oxygen is not a greenhouse gas, it can be used as a top-down constraint on the carbon cycle. The variation observations of oxygen in the atmosphere are very small, in the order of the few ppm's. This presents the main technical challenge for measurement as a very high level of precision is required and only few methods including mass spectrometry, fuel cell, and paramagnetic are capable of overcoming it. Here we present new developments of a high-precision gas analyzer that utilizes the technique of Cavity Ring-Down Spectroscopy to measure oxygen concentration and oxygen isotope. Its compact and ruggedness design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous monitoring of atmospheric oxygen level. Measurements have a 1-σ 5-minute averaging precision of 1-2 ppm for O2 over a dynamic range of 0-20%. We will present supplemental data acquired from our 10m tower measurements in Santa Clara, CA.

Assessment of water quality and factors affecting dissolved oxygen in the Sangamon River, Decatur to Riverton, Illinois, summer 1982

USGS Publications Warehouse

Schmidt, A.R.; Stamer, J.K.

1987-01-01

Water quality and processes that affect the dissolved-oxygen concentration in a 45.9 mile reach of the Sangamon River from Decatur to Riverton, Illinois, were determined from data collected during low-flow periods in the summer of 1982. Relations among dissolved oxygen, water discharge, biochemical oxygen demand, ammonia and nitrite plus nitrate concentrations, and photosynthetic-oxygen production were simulated using a one-dimensional, steady-state computer model. Average dissolved oxygen concentrations ranged from 8.0 milligrams per liter at the upstream end of the study reach at Decatur to 5.2 milligrams per liter 12.2 miles downstream. Ammonia concentrations ranged from 45 milligrams per liter at the mouth of Stevens Creek (2.6 miles downstream from Decatur) to 0.03 milligram per liter at the downstream end of the study reach. Un-ionized ammonia concentrations exceeded the maximum concentration specified in the State water quality standard (0.04 milligram per liter) throughout most of the study reach. Model simulations indicated that oxidation of ammonia to form nitrite plus nitrate was the most significant process leading to low dissolved oxygen concentrations in the river. (USGS)

Risk assessment, cross-resistance potential, and biochemical mechanism of resistance to emamectin benzoate in a field strain of house fly (Musca domestica Linnaeus).

PubMed

Khan, Hafiz Azhar Ali; Akram, Waseem; Khan, Tiyyabah; Haider, Muhammad Saleem; Iqbal, Naeem; Zubair, Muhammad

2016-05-01

Reduced sensitivity to insecticides in insect pests often results in control failures and increases in the dose and frequency of applications, ultimately polluting the environment. Reduced sensitivity to emamectin benzoate, a broad-spectrum agrochemical belonging to the avermectin group of pesticides, was reported in house flies (Musca domestica L.) collected from Punjab, Pakistan, in 2013. The aim of the present study was to investigate the risk for resistance development, biochemical mechanism, and cross-resistance potential to other insecticides in an emamectin benzoate selected (EB-SEL) strain of house flies. A field-collected strain showing reduced sensitivity to emamectin was re-selected in the laboratory for five consecutive generations and compared with a laboratory susceptible (Lab-Susceptible) reference strain, using bioassays. The field strain showed rapid development of resistance to emamectin (resistance ratio (RR) increased from 35.15 to 149.26-fold) as a result of selection experiments; however, resistance declined when the selection pressure uplifted. The EB-SEL strain showed reduction in resistance to abamectin, indoxacarb, and thiamethoxam. The results of synergism experiments using piperonyl butoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) enzyme inhibitors and biochemical analyses revealed that the metabolic resistance mechanism was not responsible in developing emamectin resistance in the EB-SEL strain. In conclusion, the risk for the rapid development of emamectin resistance under continuous selection pressure suggests using a multifaceted integrated pest management approach for house flies. Moreover, the instable nature of emamectin resistance in the EB-SEL strain and lack of cross-resistance to other insecticides provide windows for the rotational use of insecticides with different modes of action. This will ultimately reduce emamectin selection pressure and help improving management programs for house flies without polluting the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on potency of municipal solid waste conversion into renewable energy by thermal incineration and bioconversion: case study of Medan city

NASA Astrophysics Data System (ADS)

Sarah, Maya; Misran, Erni

2018-03-01

Municipal solid waste (MSW) in Medan City is facing problems either with the quantity and management of MSW. Local authority only dumped approximately 73.9% MSW in the landfill over the years. Spontaneous phenomena of methane formation in dumping site indicates the potency of MSW conversion into energy by biochemical conversion. On the contrary, the presence of plastics, woods, papers, etc. in the MSW show the potency of MSW to be treated by thermal conversion. Both thermal incineration and anaerobic digestion may convert MSW Medan City into energy. This study evaluates potency of MSW conversion into renewable energy using proximate and ultimate analysis. Overall, MSW of Medan City has the opportunities to be converted into energy by both thermal and biochemical conversion with a special requirement such as pre-dry the MSW prior incineration process and degrade organic MSW in a bioreactor.

Biochemical Reversal of Aging

NASA Astrophysics Data System (ADS)

Ely, John T. A.

2006-03-01

We cite our progress on biochemical reversal of aging. However, it may be circa 2 years before we have necessary substances at low cost. Meanwhile, without them, a number of measures can be adopted providing marked improvement for the problems of aging in modern societies. For example, enzymes are needed to excrete toxins that accelerate aging; Hg is the ultimate toxin that disables all enzymes (including those needed to excrete Hg itself). Low Hg level in the urine, due to loss of excretory ability, causes the diagnosis of Hg toxicity to almost always be missed. Hg sources must be removed from the body! Another example is excess sugar; hyperglycemia decreases intracellular ascorbic acid (AA) by competitively inhibiting the insulin- mediated active transport of AA into cells. Thus, immunity is impaired by low leucocyte AA. AA is needed for new proteins in aging tissues. Humans must supplement AA; their need same as in AA-synthesizing mammals.

Selenium- and tellurium-containing multifunctional redox agents as biochemical redox modulators with selective cytotoxicity.

PubMed

Jamier, Vincent; Ba, Lalla A; Jacob, Claus

2010-09-24

Various human diseases, including different types of cancer, are associated with a disturbed intracellular redox balance and oxidative stress (OS). The past decade has witnessed the emergence of redox-modulating compounds able to utilize such pre-existing disturbances in the redox state of sick cells for therapeutic advantage. Selenium- and tellurium-based agents turn the oxidizing redox environment present in certain cancer cells into a lethal cocktail of reactive species that push these cells over a critical redox threshold and ultimately kill them through apoptosis. This kind of toxicity is highly selective: normal, healthy cells remain largely unaffected, since changes to their naturally low levels of oxidizing species produce little effect. To further improve selectivity, multifunctional sensor/effector agents are now required that recognize the biochemical signature of OS in target cells. The synthesis of such compounds provides interesting challenges for chemistry in the future.

Polyphenol Oxidases in Crops: Biochemical, Physiological and Genetic Aspects

PubMed Central

Taranto, Francesca; Pasqualone, Antonella; Mangini, Giacomo; Tripodi, Pasquale; Miazzi, Monica Marilena; Pavan, Stefano; Montemurro, Cinzia

2017-01-01

Enzymatic browning is a colour reaction occurring in plants, including cereals, fruit and horticultural crops, due to oxidation during postharvest processing and storage. This has a negative impact on the colour, flavour, nutritional properties and shelf life of food products. Browning is usually caused by polyphenol oxidases (PPOs), following cell damage caused by senescence, wounding and the attack of pests and pathogens. Several studies indicated that PPOs play a role in plant immunity, and emerging evidence suggested that PPOs might also be involved in other physiological processes. Genomic investigations ultimately led to the isolation of PPO homologs in several crops, which will be possibly characterized at the functional level in the near future. Here, focusing on the botanic families of Poaceae and Solanaceae, we provide an overview on available scientific literature on PPOs, resulting in useful information on biochemical, physiological and genetic aspects. PMID:28208645

Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate

PubMed Central

Zarafeta, Dimitra; Kissas, Dimitrios; Sayer, Christopher; Gudbergsdottir, Sóley R.; Ladoukakis, Efthymios; Isupov, Michail N.; Chatziioannou, Aristotelis; Peng, Xu; Littlechild, Jennifer A.; Skretas, Georgios; Kolisis, Fragiskos N.

2016-01-01

With the ultimate goal of identifying robust cellulases for industrial biocatalytic conversions, we have isolated and characterized a new thermostable and very halotolerant GH5 cellulase. This new enzyme, termed CelDZ1, was identified by bioinformatic analysis from the genome of a polysaccharide-enrichment culture isolate, initiated from material collected from an Icelandic hot spring. Biochemical characterization of CelDZ1 revealed that it is a glycoside hydrolase with optimal activity at 70°C and pH 5.0 that exhibits good thermostability, high halotolerance at near-saturating salt concentrations, and resistance towards metal ions and other denaturing agents. X-ray crystallography of the new enzyme showed that CelDZ1 is the first reported cellulase structure that lacks the defined sugar-binding 2 subsite and revealed structural features which provide potential explanations of its biochemical characteristics. PMID:26741138

Do the same traffic rules apply? Directional chromosome segregation by SpoIIIE and FtsK.

PubMed

Besprozvannaya, Marina; Burton, Briana M

2014-08-01

Over a decade of studies have tackled the question of how FtsK/SpoIIIE translocases establish and maintain directional DNA translocation during chromosome segregation in bacteria. FtsK/SpoIIIE translocases move DNA in a highly processive, directional manner, where directionality is facilitated by sequences on the substrate DNA molecules that are being transported. In recent years, structural, biochemical, single-molecule and high-resolution microscopic studies have provided new insight into the mechanistic details of directional DNA segregation. Out of this body of work, a series of models have emerged and, ultimately, yielded two seemingly opposing models: the loading model and the target search model. We review these recent mechanistic insights into directional DNA movement and discuss the data that may serve to unite these suggested models, as well as propose future directions that may ultimately solve the debate. © 2014 John Wiley & Sons Ltd.

Spatial Frequency Domain Imaging of Port Wine Stain Biochemical Composition in Response to Laser Therapy: A Pilot Study

PubMed Central

Mazhar, Amaan; Sharif, Seyed A.; Cuccia, J. David; Nelson, J. Stuart; Kelly, Kristen M.; Durkin, Anthony J.

2012-01-01

Background and Objective Objective methods to assess port wine stain (PWS) response to laser treatment have been the subject of various research efforts for several years. Herein, we present a pilot study using a newly developed, light emitting diode (LED) based spatial frequency domain imaging (SFDI) device to record quantitatively biochemical compositional changes in PWS after laser therapy. Study Design/Patients and Methods A SFDI system was used to image before, and after, five PWS treatment sessions [n = 4 subjects (one subject was imaged before and after two consecutive laser treatments)]. SFDI derived wide-field optical properties (absorption and scattering) and tissue chromophore concentrations including oxy-hemoglobin (ctO2Hb), deoxy-hemoglobin (ctHHb), total hemoglobin (ctTHb), and tissue oxygen saturation (stO2) are presented for skin imaged prior to and immediately after laser treatment. The SFDI derived images were analyzed by comparing the above measurements in PWS to those of normal skin and tracking changes immediately after laser exposure. Results Elevated oxy-hemoglobin (>20%) and tissue oxygen saturation (>5%) were measured in all PWS lesions and compared to values for normal skin prior to treatment. Laser treatment resulted in an increase in deoxy-hemoglobin (>100%), decrease in tissue oxygen saturation (>10%), and reduced scattering (>15%) in all PWS lesions. One subject was followed before and after two consecutive laser treatments and the overall improvement in PWS lesion blanching was quantitatively assessed by measuring a 45% decrease in dermal blood volume. Conclusion SFDI is a rapid non-contact wide-field optical technique that shows potential as an imaging device that can be used to quantify biochemical compositional changes in PWS after laser therapy. Future work will investigate the potential of SFDI to provide intra-operative guidance for laser therapy of PWS lesions on an individual patient basis. PMID:22911574

Biochemical and Structural Characterisation of DNA Ligases from Bacteria and Archaea.

PubMed

Pergolizzi, Giulia; Wagner, Gerd K; Bowater, Richard Peter

2016-08-31

DNA ligases are enzymes that seal breaks in the backbones of DNA, leading to them being essential for the survival of all organisms. DNA ligases have been studied from many different types of cells and organisms and shown to have diverse sizes and sequences, with well conserved specific sequences that are required for enzymatic activity. A significant number of DNA ligases have been isolated or prepared in recombinant forms and, here, we review their biochemical and structural characterisation. All DNA ligases contain an essential lysine that transfers an adenylate group from a co-factor to the 5'-phosphate of the DNA end that will ultimately be joined to the 3'-hydroxyl of the neighbouring DNA strand. The essential DNA ligases in bacteria use nicotinamide adenine dinucleotide ( β -NAD + ) as their co-factor whereas those that are essential in other cells use adenosine-5'-triphosphate (ATP) as their co-factor. This observation suggests that the essential bacterial enzyme could be targeted by novel antibiotics and the complex molecular structure of β -NAD + affords multiple opportunities for chemical modification. Several recent studies have synthesised novel derivatives and their biological activity against a range of DNA ligases has been evaluated as inhibitors for drug discovery and/or non-natural substrates for biochemical applications. Here, we review the recent advances that herald new opportunities to alter the biochemical activities of these important enzymes. The recent development of modified derivatives of nucleotides highlights that the continued combination of structural, biochemical and biophysical techniques will be useful in targeting these essential cellular enzymes. ©2016 The Author(s).

Autoamplificatory singlet oxygen generation sensitizes tumor cells for intercellular apoptosis-inducing signaling.

PubMed

Bauer, Georg

2018-06-01

Tumor cells express NADPH oxidase-1 (NOX1) in their membrane and control NOX1-based intercellular reactive oxygen and nitrogen species (ROS/RNS)-dependent apoptosis-inducing signaling through membrane-associated catalase and superoxide dismutase. of tumor cells with high concentrations of H 2 O 2 , peroxnitrite, HOCl, or increasing the concentration of cell-derived NO causes initial generation of singlet oxygen and local inactivation of membrane-associated catalase. As a result, free peroxynitrite and H 2 O 2 interact and generate secondary singlet oxygen. Inactivation of further catalase molecules by secondary singlet oxygen leads to auto-amplification of singlet oxygen generation and catalase inactivation. This allows reactivation of intercellular ROS/RNS-signaling and selective apoptosis induction in tumor cells. The initial singlet oxygen generation seems to be the critical point in this complex biochemical multistep mechanism. Initial singlet oxygen generation requires the interaction between distinct tumor cell-derived ROS and RNS and may also depend on either the induction of NO synthase expression or NOX1 activation through the FAS receptor. FAS receptor activation can be achieved by singlet oxygen. Autoamplificatory generation of singlet oxygen through the interaction between peroxynitrite and hydrogen peroxide inherits a rich potential for the establishment of synergistic effects that may be instrumental for novel approaches of tumor therapy with high selectivity towards malignant cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Timescales of Oxygenation Following the Evolution of Oxygenic Photosynthesis

NASA Astrophysics Data System (ADS)

Ward, Lewis M.; Kirschvink, Joseph L.; Fischer, Woodward W.

2016-03-01

Among the most important bioenergetic innovations in the history of life was the invention of oxygenic photosynthesis—autotrophic growth by splitting water with sunlight—by Cyanobacteria. It is widely accepted that the invention of oxygenic photosynthesis ultimately resulted in the rise of oxygen by ca. 2.35 Gya, but it is debated whether this occurred more or less immediately as a proximal result of the evolution of oxygenic Cyanobacteria or whether they originated several hundred million to more than one billion years earlier in Earth history. The latter hypothesis involves a prolonged period during which oxygen production rates were insufficient to oxidize the atmosphere, potentially due to redox buffering by reduced species such as higher concentrations of ferrous iron in seawater. To examine the characteristic timescales for environmental oxygenation following the evolution of oxygenic photosynthesis, we applied a simple mathematical approach that captures many of the salient features of the major biogeochemical fluxes and reservoirs present in Archean and early Paleoproterozoic surface environments. Calculations illustrate that oxygenation would have overwhelmed redox buffers within ~100 kyr following the emergence of oxygenic photosynthesis, a geologically short amount of time unless rates of primary production were far lower than commonly expected. Fundamentally, this result arises because of the multiscale nature of the carbon and oxygen cycles: rates of gross primary production are orders of magnitude too fast for oxygen to be masked by Earth's geological buffers, and can only be effectively matched by respiration at non-negligible O2 concentrations. These results suggest that oxygenic photosynthesis arose shortly before the rise of oxygen, not hundreds of millions of years before it.

Timescales of Oxygenation Following the Evolution of Oxygenic Photosynthesis.

PubMed

Ward, Lewis M; Kirschvink, Joseph L; Fischer, Woodward W

2016-03-01

Among the most important bioenergetic innovations in the history of life was the invention of oxygenic photosynthesis-autotrophic growth by splitting water with sunlight-by Cyanobacteria. It is widely accepted that the invention of oxygenic photosynthesis ultimately resulted in the rise of oxygen by ca. 2.35 Gya, but it is debated whether this occurred more or less immediately as a proximal result of the evolution of oxygenic Cyanobacteria or whether they originated several hundred million to more than one billion years earlier in Earth history. The latter hypothesis involves a prolonged period during which oxygen production rates were insufficient to oxidize the atmosphere, potentially due to redox buffering by reduced species such as higher concentrations of ferrous iron in seawater. To examine the characteristic timescales for environmental oxygenation following the evolution of oxygenic photosynthesis, we applied a simple mathematical approach that captures many of the salient features of the major biogeochemical fluxes and reservoirs present in Archean and early Paleoproterozoic surface environments. Calculations illustrate that oxygenation would have overwhelmed redox buffers within ~100 kyr following the emergence of oxygenic photosynthesis, a geologically short amount of time unless rates of primary production were far lower than commonly expected. Fundamentally, this result arises because of the multiscale nature of the carbon and oxygen cycles: rates of gross primary production are orders of magnitude too fast for oxygen to be masked by Earth's geological buffers, and can only be effectively matched by respiration at non-negligible O2 concentrations. These results suggest that oxygenic photosynthesis arose shortly before the rise of oxygen, not hundreds of millions of years before it.

Lessons from (patho)physiological tissue stiffness and their implications for drug screening, drug delivery and regenerative medicine.

PubMed

Chen, Wen Li Kelly; Simmons, Craig A

2011-04-30

Diseased tissues are noted for their compromised mechanical properties, which contribute to organ failure; regeneration entails restoration of tissue structure and thereby functions. Thus, the physical signature of a tissue is closely associated with its biological function. In this review, we consider a mechanics-centric view of disease and regeneration by drawing parallels between in vivo tissue-level observations and corroborative cellular evidence in vitro to demonstrate the importance of the mechanical stiffness of the extracellular matrix in these processes. This is not intended to devalue the importance of biochemical signaling; in fact, as we discuss, many mechanical stiffness-driven processes not only require cooperation with biochemical cues, but they ultimately converge at common signaling cascades to influence cell and tissue function in an integrative manner. The study of how physical and biochemical signals collectively modulate cell function not only brings forth a more holistic understanding of cell (patho)biology, but it also creates opportunities to control material properties to improve culture platforms for research and drug screening and aid in the rationale design of biomaterials for molecular therapy and tissue engineering applications. Copyright © 2011 Elsevier B.V. All rights reserved.

The WAVE2 complex regulates actin cytoskeletal reorganization and CRAC-mediated calcium entry during T cell activation.

PubMed

Nolz, Jeffrey C; Gomez, Timothy S; Zhu, Peimin; Li, Shuixing; Medeiros, Ricardo B; Shimizu, Yoji; Burkhardt, Janis K; Freedman, Bruce D; Billadeau, Daniel D

2006-01-10

The engagement of the T cell receptor results in actin cytoskeletal reorganization at the immune synapse (IS) and the triggering of biochemical signaling cascades leading to gene regulation and, ultimately, cellular activation. Recent studies have identified the WAVE family of proteins as critical mediators of Rac1-induced actin reorganization in other cell types. However, whether these proteins participate in actin reorganization at the IS or signaling pathways in T cells has not been investigated. By using a combination of biochemical, genetic, and cell biology approaches, we provide evidence that WAVE2 is recruited to the IS, is biochemically modified, and is required for actin reorganization and beta-integrin-mediated adhesion after TCR crosslinking. Moreover, we show that WAVE2 regulates calcium entry at a point distal to PLCgamma1 activation and IP(3)-mediated store release. These data reveal a role for WAVE2 in regulating multiple pathways leading to T cell activation. In particular, this work shows that WAVE2 is a key component of the actin regulatory machinery in T cells and that it also participates in linking intracellular calcium store depletion to calcium release-activated calcium (CRAC) channel activation.

Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

NASA Astrophysics Data System (ADS)

Philben, Michael; Holmquist, James; MacDonald, Glen; Duan, Dandan; Kaiser, Karl; Benner, Ronald

2015-06-01

The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from ~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an increasing contribution of vascular plants to the vegetation.

Characterization of stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, 1998-99

USGS Publications Warehouse

Rodriguez, Jose M.

2000-01-01

Stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, were characterized from June 1998 to July 1999 by measuring the flow rate at two outfalls, delineating the drainage areas for each outfall, and calculating the volume of the stormwater discharges. Stormwater-discharge samples were collected and analyzed to determine the quality of the discharges. Constituent loads and loads per area were estimated for each drainage area. The studied drainage subareas covered approximately 46 percent of the total area of the Las Flores Industrial Park. Industrial groups represented in the study areas include manufacturers of textile, electronics, paper, fabricated metal, plastic, and chemical products. The concentrations of oil and grease (1 to 6 milligrams per liter), biochemical oxygen demand (4.7 to 16 milligrams per liter), total organic carbon (5.8 to 36 milligrams per liter), total suspended solids (28 to 100 milligrams per liter), and total phosphorous (0.11 to 0.78 milligrams per liter) from all the samples collected were less than the U.S. Environmental Protection Agency stormwater benchmark concentrations. Concentrations of chemical oxygen demand (15.8 to 157 milligrams per liter) and nitrate and nitrite (0.06 to 1.75 milligrams per liter) exceeded benchmark concentrations at one of the studied drainage areas. Total Kjeldahl nitrogen concentrations (1.00 to 3.20 milligrams per liter) exceeded the benchmark concentrations at the two studied drainage areas. Maximum concentrations for oil and grease, biochemical oxygen demand, chemical oxygen demand, total organic carbon, total Kjeldahl nitrogen, nitrate plus nitrite, and total phosphorous were detected in an area where electronics, plastics, and chemical products are currently manufactured. The maximum concentration of total suspended solids was detected at an area where textile, paper, plastic, chemical, and fabricated metal products are manufactured.

Development and Evaluation of an Online CO2 Evolution Test and a Multicomponent Biodegradation Test System

PubMed Central

Strotmann, Uwe; Reuschenbach, Peter; Schwarz, Helmut; Pagga, Udo

2004-01-01

Well-established biodegradation tests use biogenously evolved carbon dioxide (CO2) as an analytical parameter to determine the ultimate biodegradability of substances. A newly developed analytical technique based on the continuous online measurement of conductivity showed its suitability over other techniques. It could be demonstrated that the method met all criteria of established biodegradation tests, gave continuous biodegradation curves, and was more reliable than other tests. In parallel experiments, only small variations in the biodegradation pattern occurred. When comparing the new online CO2 method with existing CO2 evolution tests, growth rates and lag periods were similar and only the final degree of biodegradation of aniline was slightly lower. A further test development was the unification and parallel measurement of all three important summary parameters for biodegradation—i.e., CO2 evolution, determination of the biochemical oxygen demand (BOD), and removal of dissolved organic carbon (DOC)—in a multicomponent biodegradation test system (MCBTS). The practicability of this test method was demonstrated with aniline. This test system had advantages for poorly water-soluble and highly volatile compounds and allowed the determination of the carbon fraction integrated into biomass (heterotrophic yield). The integrated online measurements of CO2 and BOD systems produced continuous degradation curves, which better met the stringent criteria of ready biodegradability (60% biodegradation in a 10-day window). Furthermore the data could be used to calculate maximal growth rates for the modeling of biodegradation processes. PMID:15294794

Molecular Pathways: Inflammation-associated nitric-oxide production as a cancer-supporting redox mechanism and a potential therapeutic target

PubMed Central

Grimm, Elizabeth A.; Sikora, Andrew G.; Ekmekcioglu, Suhendan

2013-01-01

It is widely accepted that many cancers express features of inflammation, driven by both microenvironmental cells and factors, and the intrinsic production of inflammation-associated mediators from malignant cells themselves. Inflammation results in intracellular oxidative stress, with the ultimate biochemical oxidants composed of reactive nitrogens and oxygens. Although the role of inflammation in carcinogensis is well accepted, we now present data that inflammatory processes are also active in the maintenance phase of many aggressive forms of cancer. The oxidative stress of inflammation is proposed to drive a continuous process of DNA adducts and crosslinks, as well as posttranslational modifications to lipids and proteins that we argue support growth and survival. In this Perspective we introduce data on the emerging science of inflammation-driven posttranslational modifications on proteins responsible for driving growth, angiogenesis, immunosuppression, and inhibition of apoptosis. Examples include data from human melanoma, breast, head and neck, lung, and colon cancers. Fortunately, numerous anti-oxidant agents are clinically available, and we further propose that the pharmacological attenuation of these inflammatory processes, particularly the reactive nitrogen species, will restore the cancer cells to an apoptosis-permissive and growth inhibitory state. Our mouse model data using an arginine antagonist that prevents enzymatic production of nitric oxide, directly supports this view. We contend that selected antioxidants be considered as part of the cancer treatment approach, as they are likely to provide a novel and mechanistically justified addition for therapeutic benefit. PMID:23868870

40 CFR 412.2 - General definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

....23. (c) Fecal coliform means the bacterial count (Parameter 1) at 40 CFR 136.3 in Table 1A, which... with approved methods of analysis in Table 1B at 40 CFR 136.3 are defined as follows: (1) Ammonia (as N) means ammonia reported as nitrogen. (2) BOD5 means 5-day biochemical oxygen demand. (3) Nitrate (as N...

[Biochemical evaluation of metabolic disorders in the tissues of the locomotor system in patients with occupational diseases caused by physical stress].

PubMed

Shatskaia, N N; Tarasova, A A; Fedorova, V I; Shardakova, E F; Selezneva, A I; Fedosova, N F

1991-01-01

A group of patients with occupational disease and female sewing-machine operators were medically examined with a broad set of biochemical techniques aimed at the detection of metabolic disorders in the locomotor system tissues. Noninflammatory dystrophic changes were found. The muscular component was dominating in comparison with the osseous one in the genesis of the degenerative dystrophic processes, which manifested in the clinical course. Laboratory manifestations were revealed related to the lowered energy supply and oxygenation of the skeleton muscles in patients with neuromuscular and osteo-muscular++ syndromes. The metabolic disorders were diagnosed at the early stages of myalgia.

Biochemical Basis of Sestrin Physiological Activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Allison; Cho, Chun-Seok; Namkoong, Sim

Excessive accumulation of reactive oxygen species (ROS) and chronic activation of mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) are well-characterized promoters of aging and age-associated degenerative pathologies. Sestrins, a family of highly conserved stress-inducible proteins, are important negative regulators of both ROS and mTORC1 signaling pathways; however, the mechanistic basis of how Sestrins suppress these pathways remains elusive. In the past couple of years, breakthrough discoveries about Sestrin signaling and its molecular nature have markedly increased our biochemical understanding of Sestrin function. These discoveries have also uncovered new potential therapeutic strategies that may eventually enable us to attenuate agingmore » and age-associated diseases.« less

26 CFR 1.43-2 - Qualified enhanced oil recovery project.

Code of Federal Regulations, 2012 CFR

2012-04-01

... combustion. The combustion of oil or fuel in the reservoir sustained by injection of air, oxygen-enriched air... meaning of section 638(1)); (3) The first injection of liquids, gases, or other matter for the project (as... amount of crude oil that ultimately will be recovered. (c) First injection of liquids, gases, or other...

26 CFR 1.43-2 - Qualified enhanced oil recovery project.

Code of Federal Regulations, 2013 CFR

2013-04-01

... combustion. The combustion of oil or fuel in the reservoir sustained by injection of air, oxygen-enriched air... meaning of section 638(1)); (3) The first injection of liquids, gases, or other matter for the project (as... amount of crude oil that ultimately will be recovered. (c) First injection of liquids, gases, or other...

Using carbon emissions, oxygen consumption, and energy retention estimates to calculate dietary energy partitioning and estimate forage intake by beef steers

USDA-ARS?s Scientific Manuscript database

Take home Message: Estimating ME intake by grazing cattle seems possible using respiration gas exchange estimates. Introduction: We hypothesized that carbon dioxide, methane, and oxigen exchange estimates in breath clouds could be used as biomarkers to ultimately estimate dry matter intake in grazi...

Characteristics of water quality and streamflow, Passaic River basin above Little Falls, New Jersey

USGS Publications Warehouse

Anderson, Peter W.; Faust, Samuel Denton

1973-01-01

The findings of a problem-oriented river-system investigation of the water-quality and streamflow characteristics of the Passaic River above Little Falls, N.J. (drainage area 762 sq mi) are described. Information on streamflow duration, time-of-travel measurements, and analyses of chemical, biochemical, and physical water quality are summarized. This information is used to define relations between water quality, streamflow, geology, and environmental development in the basin's hydrologic system. The existence, nature, and magnitude of long-term trends in stream quality--as measured by dissolved solids, chloride, dissolved oxygen, biochemical oxygen demand, ammonia, nitrate, and turbidity--and in streamflow toward either improvement or deterioration are appraised at selected sites within the river system. The quality of streams in the upper Passaic River basin in northeastern New Jersey is shown to be deteriorating with time. For example, biochemical oxygen demand, an indirect measure of organic matter in a stream, is increasing at most stream-quality sampling sites. Similarly, the dissolved-solids content, a measure of inorganic matter, also is increasing. These observations suggest that the Passaic River system is being used more and more as a medium for the disposal of industrial and municipal waste waters. Dissolved oxygen, an essential ingredient for the natural purification of streams receiving waste discharges, is undersaturated (that is, below theoretical solubility levels) at all sampling sites and is decreasing with time at most sites. This is another indication of the general deterioration of stream quality in the upper basin. It also indicates that the ability of the river system to receive, transport, and assimilate wastes, although exceeded now only for short periods during the summer months, may be exceeded more continually in the future if present trends hold. Decreasing ratios of ammonia to nitrate in a downstream direction on the main stem Passaic River suggests that nitrification (the biochemical conversion of ammonia to nitrate) as well as microbiological decomposition of organic matter (waste waters) is contributing to the continued and increasing undersaturation of dissolved oxygen in the river system. Passaic River streams are grouped into five general regions of isochemical quality on the basis of predominant constituents and dissolved-solids content during low flows. The predominant cations in all but one region are calcium and magnesium (exceeding 50 percent of total cations) ; in that region, where man's activities probably have altered the natural stream waters, the percentage of sodium and potassium equals that of calcium and magnesium. In two of the five regions, the predominant anion is bicarbonate; a combination of sulfate, chloride, and nitrate is predominant in the other three regions. Dissolved-solids content during low flows generally ranges from 100 to 600 milligrams per liter. Several time-of-travel measurements within the basin are reported. These data provide reasonable estimates of the time required for soluble contaminants to pass through particular parts of the river system. For example, the peak concentration of a contaminant injected into the river system at Chatham during extreme low flow would be expected to travel to Little Falls, about 31 miles, in about 13 days; but at medium flow, in about 5 days.

Therapeutic effect of forearm low level light treatment on blood flow, oxygenation, and oxygen consumption

NASA Astrophysics Data System (ADS)

Wang, Pengbo; Sun, Jiajing; Meng, Lingkang; Li, Zebin; Li, Ting

2018-02-01

Low level light/laser therapy (LLLT) is considered as a novel, non-invasive, and potential therapy in a variety of psychological and physical conditions, due to its effective intricate photobiomodulation. The mechanism of LLLT is that when cells are stimulated by photons, mitochondria produce a large quantity of ATP, which accelerates biochemical responses in the cell. It is of great significance to gain a clear insight into the change or interplay of various physiological parameters. In this study, we used functional near-infrared spectroscopy (fNIRS) and venous-occlusion plethysmography to measure the LLLT-induced changes in blood flow, oxygenation, and oxygen consumption in human forearms in vivo. Six healthy human participants (4 males and 2 females) were administered with 810-nm light emitted by LED array in ten minutes and blood flow, oxygenation and oxygen consumption were detected in the entire experiment. We found that LLLT induced an increase of blood flow and oxygen consumption on the treated site. Meanwhile, LLLT took a good role in promoting oxygenation of regional tissue, which was indicated by a significant increase of oxygenated hemoglobin concentration (Δ[HbO2]), a nearly invariable deoxygenated hemoglobin concentration (Δ[Hb]) and a increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO2] - Δ[Hb]). These results not only demonstrate enormous potential of LLLT, but help to figure out mechanisms of photobiomodulation.

Potential Role of Carotenoids as Antioxidants in Human Health and Disease

PubMed Central

Fiedor, Joanna; Burda, Květoslava

2014-01-01

Carotenoids constitute a ubiquitous group of isoprenoid pigments. They are very efficient physical quenchers of singlet oxygen and scavengers of other reactive oxygen species. Carotenoids can also act as chemical quenchers undergoing irreversible oxygenation. The molecular mechanisms underlying these reactions are still not fully understood, especially in the context of the anti- and pro-oxidant activity of carotenoids, which, although not synthesized by humans and animals, are also present in their blood and tissues, contributing to a number of biochemical processes. The antioxidant potential of carotenoids is of particular significance to human health, due to the fact that losing antioxidant-reactive oxygen species balance results in “oxidative stress”, a critical factor of the pathogenic processes of various chronic disorders. Data coming from epidemiological studies and clinical trials strongly support the observation that adequate carotenoid supplementation may significantly reduce the risk of several disorders mediated by reactive oxygen species. Here, we would like to highlight the beneficial (protective) effects of dietary carotenoid intake in exemplary widespread modern civilization diseases, i.e., cancer, cardiovascular or photosensitivity disorders, in the context of carotenoids’ unique antioxidative properties. PMID:24473231

Simulated digestion of Vitis vinifera seed powder: polyphenolic content and antioxidant properties.

PubMed

Janisch, Kerstin M; Olschläger, Carolin; Treutter, Dieter; Elstner, Erich F

2006-06-28

There is increasing evidence that reactive oxygen species arising from several enzymatic reactions are mediators of inflammatory events. Plant preparations have the potential for scavenging such reactive oxygen species. Flavans and procyanidins are bioavailable and stable during the process of cooking. This study used conditions that mimicked digestion of Vitis vinifera seed powder in the stomach (acidic preparation) and small intestine (neutral preparation). The flavonoids of these two preparations were released during simulated digestion and were determined with HPLC analysis. Biochemical model reactions relevant for the formation of reactive oxygen species in vivo at inflammatory sites were used to determine the antioxidant properties of the two preparations. The inhibition of the indicator reaction for the formation of reactive oxygen species represents a potential mechanism of the physiological activity of the corresponding preparation. The results of this work show clearly that the polyphenols released during the simulated digestion of the two preparations have good scavenging potential against superoxide radicals, hydroxyl radicals, and singlet oxygen. They protect low-density lipoprotein against copper-induced oxidation due to the copper-chelating properties and their chain-breaking abilities in lipid peroxidation.

Exhaustive Exercise-induced Oxidative Stress Alteration of Erythrocyte Oxygen Release Capacity.

PubMed

Xiong, Yanlian; Xiong, Yanlei; Wang, Yueming; Zhao, Yajin; Li, Yaojin; Ren, Yang; Wang, Ruofeng; Zhao, Mingzi; Hao, Yitong; Liu, Haibei; Wang, Xiang

2018-05-24

The aim of the present study is to explore the effect of exhaustive running exercise (ERE) in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control (C), moderate running exercise (MRE) and exhaustive running exercise groups. The thermodynamics and kinetics properties of the erythrocyte oxygen release process of different groups were tested. We also determined the degree of band-3 oxidative and phosphorylation, anion transport activity and carbonic anhydrase isoform II(CAII) activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in TBARS and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II(CAII) activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamics and kinetics properties of RBCs oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive running induced alterations in erythrocytes oxygen release thermodynamics and kinetics properties.

Void space inside the developing seed of Brassica napus and the modelling of its function

PubMed Central

Verboven, Pieter; Herremans, Els; Borisjuk, Ljudmilla; Helfen, Lukas; Ho, Quang Tri; Tschiersch, Henning; Fuchs, Johannes; Nicolaï, Bart M; Rolletschek, Hardy

2013-01-01

The developing seed essentially relies on external oxygen to fuel aerobic respiration, but it is currently unknown how oxygen diffuses into and within the seed, which structural pathways are used and what finally limits gas exchange. By applying synchrotron X-ray computed tomography to developing oilseed rape seeds we uncovered void spaces, and analysed their three-dimensional assembly. Both the testa and the hypocotyl are well endowed with void space, but in the cotyledons, spaces were small and poorly inter-connected. In silico modelling revealed a three orders of magnitude range in oxygen diffusivity from tissue to tissue, and identified major barriers to gas exchange. The oxygen pool stored in the voids is consumed about once per minute. The function of the void space was related to the tissue-specific distribution of storage oils, storage protein and starch, as well as oxygen, water, sugars, amino acids and the level of respiratory activity, analysed using a combination of magnetic resonance imaging, specific oxygen sensors, laser micro-dissection, biochemical and histological methods. We conclude that the size and inter-connectivity of void spaces are major determinants of gas exchange potential, and locally affect the respiratory activity of a developing seed. PMID:23692271

Fabrication of nanocapsule carriers from multilayer-coated vaterite calcium carbonate nanoparticles.

PubMed

Biswas, Aniket; Nagaraja, Ashvin T; McShane, Michael J

2014-12-10

Nanosized luminescent sensors were prepared as reagents for optical sensing and imaging of oxygen using ratiometric emission properties of a two-dye system. Polymeric capsules were fabricated utilizing poly(vinylsulfonic acid) (PVSA)-stabilized vaterite CaCO3 nanoparticles (CCNPs) as sacrificial templates. The buffer and polymeric surfactant requirements of the layer-by-layer (LbL) process were evaluated toward deposition of multilayer coatings and, ultimately, formation of hollow capsules using these interesting materials. CCNPs were found to be more stable in alkaline NaHCO3 buffer after repeated cycles of washing under sonication and resuspension. An intermediate PVSA concentration was required to maximize the loading of oxygen-sensitive porphyrin and oxygen-insensitive fluorescent nanoparticles in the CCNPs while maintaining minimal nanoparticle size. The CCNPs were then coated with polyelectrolyte multilayers and subsequent removal of the CaCO3 core yielded nanocapsules containing dye and fluorescent nanoparticles. The resulting nanocapsules with encapsulated luminophores functioned effectively as oxygen sensors with a quenching response of 89.28 ± 2.59%, and O2 (S = 1/2) = 20.91 μM of dissolved oxygen.

Combined pulse-oximeter-NIRS system for biotissue diagnostics

NASA Astrophysics Data System (ADS)

Hovhannisyan, Vladimir A.

2005-08-01

Multi-wavelength (670, 805, 848 and 905 nm), multi-detector device for non-invasive measurement of biochemical components concentration in human or animal tissues, combining the methods of conventional pulse-oximetry and near infrared spectroscopy, is developed. The portable and clinically applicable system allows to measure heart pulse rate, oxygen saturation of arterial hemoglobin (pulse-oximetry method) and local absolute concentration of oxyhemoglobin, deoxyhemoglobin and oxidized cytochrome aa3 or other IR absorbed compounds (NIRS method). The system can be applied in monitoring of oxygen availability and utilization by the brain in neonatal and adults, neuro- traumatology, intensive care medicine, transplantation and plastic surgery, in sport, high-altitude and aviation medicine.

Calculation of weighted averages approach for the estimation of ping tolerance values

USGS Publications Warehouse

Silalom, S.; Carter, J.L.; Chantaramongkol, P.

2010-01-01

A biotic index was created and proposed as a tool to assess water quality in the Upper Mae Ping sub-watersheds. The Ping biotic index was calculated by utilizing Ping tolerance values. This paper presents the calculation of Ping tolerance values of the collected macroinvertebrates. Ping tolerance values were estimated by a weighted averages approach based on the abundance of macroinvertebrates and six chemical constituents that include conductivity, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen and orthophosphate. Ping tolerance values range from 0 to 10. Macroinvertebrates assigned a 0 are very sensitive to organic pollution while macroinvertebrates assigned 10 are highly tolerant to pollution.

Techniques for estimating the quantity and quality of storm runoff from urban watersheds of Jefferson County, Kentucky

USGS Publications Warehouse

Evaldi, R.D.; Moore, B.L.

1994-01-01

Linear regression models are presented for estimating storm-runoff volumes, and mean con- centrations and loads of selected constituents in storm runoff from urban watersheds of Jefferson County, Kentucky. Constituents modeled include dissolved oxygen, biochemical and chemical oxygen demand, total and suspended solids, volatile residue, nitrogen, phosphorus and phosphate, calcium, magnesium, barium, copper, iron, lead, and zinc. Model estimations are a function of drainage area, percentage of impervious area, climatological data, and land uses. Estimation models are based on runoff volumes, and concen- trations and loads of constituents in runoff measured at 6 stormwater outfalls and 25 streams in Jefferson County.

Effect of dissolved oxygen on two bacterial pathogens examined using ATR-FTIR spectroscopy, microelectrophoresis, and potentiometric titration.

PubMed

Castro, Felipe D; Sedman, Jacqueline; Ismail, Ashraf A; Asadishad, Bahareh; Tufenkji, Nathalie

2010-06-01

The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest. Titration of bacterial cells is used to identify the major proton-active functional groups and the overall concentration of these cell surface ligands at the cell membrane. Analysis of titration data shows notable differences between strains and conditions, confirming the appropriateness of this tool for an overall charge characterization. ATR-FTIR spectroscopy of whole cells is used to further characterize the bacterial biochemical composition and macromolecular structures that might be involved in the development of the net surficial charge of the organisms examined. The evaluation of the integrated intensities of HPO(2)(-) and carbohydrate absorption bands in the IR spectra reveals clear differences between growth protocols. Taken together, the three techniques seem to indicate that the dissolved oxygen tension during cell growth or acclimation can noticeably influence the expression of cell surface molecules and the measurable cell surface charge, though in a strain-dependent fashion.

Effects of wastewater effluent on the South Platte River from Littleton to Denver

USGS Publications Warehouse

Spahr, N.E.; Blakely, S.R.

1985-01-01

The U.S. Geological Survey 's one-dimensional steady-state water quality model was used to investigate the effects of the effluent from the Bi-City WWTP (Wastewater Treatment Plant) on the South Platte River. The Bi-City WWTP is operated by the Cities of Littleton and Englewood. The model was calibrated from a 14.5 mile reach for 5-day carbonaceous biochemical oxygen demand, organic, ammonia, nitrite and nitrate using data collected during September 1983. Model verification was completed using data collected during October 1982 and January 1984 for all constituents except nitrite nitrogen. Nitrite nitrogen could not be verified for the cold temperature conditions of January of 1984. Measured benthic sediment oxygen demand used in model ranged from 1.01 to 2.77 grams per square meter per day. Model simulations were made for an estimated 7-day, 10-year discharge of 18 cubic feet per second, upstream from the outfall of the WWTP. Two groups of simulations were made for both warm and cold temperature conditions. In the first group of simulation variations were made in effluent 5-day carbonaceous biochemical oxygen demand concentrations and flow rates. The second group of simulations varied the amount of nitrogen discharged as ammonia and nitrate. The extent of the mixing zone downstream of the WWTP outfall was determined by injecting Rhodamine WT dye into the effluent. The mixing zone was found to extend 0.8 miles during low-flow conditions. (USGS)

Simulation of flow and water quality of the Arroyo Colorado, Texas, 1989-99

USGS Publications Warehouse

Raines, Timothy H.; Miranda, Roger M.

2002-01-01

A model parameter set for use with the Hydrological Simulation Program—FORTRAN watershed model was developed to simulate flow and water quality for selected properties and constituents for the Arroyo Colorado from the city of Mission to the Laguna Madre, Texas. The model simulates flow, selected water-quality properties, and constituent concentrations. The model can be used to estimate a total maximum daily load for selected properties and constituents in the Arroyo Colorado. The model was calibrated and tested for flow with data measured during 1989–99 at three streamflow-gaging stations. The errors for total flow volume ranged from -0.1 to 29.0 percent, and the errors for total storm volume ranged from -15.6 to 8.4 percent. The model was calibrated and tested for water quality for seven properties and constituents with 1989–99 data. The model was calibrated sequentially for suspended sediment, water temperature, biochemical oxygen demand, dissolved oxygen, nitrate nitrogen, ammonia nitrogen, and orthophosphate. The simulated concentrations of the selected properties and constituents generally matched the measured concentrations available for the calibration and testing periods. The model was used to simulate total point- and nonpoint-source loads for selected properties and constituents for 1989–99 for urban, natural, and agricultural land-use types. About one-third to one-half of the biochemical oxygen demand and nutrient loads are from urban point and nonpoint sources, although only 13 percent of the total land use in the basin is urban.

Life style and biochemical adaptation in Antarctic fishes

NASA Astrophysics Data System (ADS)

di Prisco, Guido

2000-12-01

Respiration and metabolism are under investigation in Antarctic fish, in an effort to understand the interplay between ecology and biochemical and physiological processes. Fish of the dominant suborder Notothenioidei are red-blooded, except Channichthyidae (the most phyletically derived family), whose genomes retain transcriptionally inactive DNA sequences closely related to the α-globin gene of red-blooded notothenioids and have lost the β-globin locus. Our structure/function studies on 38 of the 80 red-blooded species are aimed at correlating sequence, multiplicity and oxygen binding with ecological constraints and at obtaining phylogenetic information on evolution. For comparative purposes, this work has been extended to non-Antarctic notothenioids. All sluggish bottom dwellers have a single major hemoglobin (Hb) and often a minor, functionally similar one. Three species of the family Nototheniidae have different life styles. They have uniquely specialised oxygen-transport systems, adjusted to the mode of life of each species. Artedidraconidae have a single Hb, lacking oxygen-binding cooperativity, similar to the ancestral hemoproteins of primitive organisms. The amino acid sequences are currently used in the molecular modelling approach. The study of several enzymes with key roles in metabolism (e.g. glucose-6-phosphate dehydrogenase, L-glutamate dehydrogenase, phosphorylase b, carbonic anhydrase) indicate that some aspects of the molecular structure (e.g. molecular mass, number of subunits, amino acid sequence, temperature of irreversible heat inactivation) have been conserved during development of cold adaptation. However, high catalytic efficiency, possibly due to subtle molecular changes, is observed at low temperature.

Rapid integrated water quality evaluation of Mahisagar river using benthic macroinvertebrates.

PubMed

Bhadrecha, M H; Khatri, Nitasha; Tyagi, Sanjiv

2016-04-01

The water quality of Mahisagar river, near Galteshwar in Kheda district of Gujarat, India, was assessed through a rapid integrated technique by physicochemical parameters as well as benthic macroinvertebrates. Physicochemical parameters retrieved were pH, color, conductivity, total solids, total suspended solids, total dissolved solids, chlorides, total hardness, calcium hardness, magnesium hardness, alkalinity, turbidity, ammoniacal nitrogen, chemical oxygen demand, biochemical oxygen demand, dissolved oxygen, sulfates, and nitrates. The biological indices calculated were BMWP (Bio Monitoring Working Party) score or saprobic score and sequential comparison index or diversity score. In total, 37 families were encountered along the studied river stretch. The findings indicate that the water quality of Mahisagar river at sampled locations is “slightly polluted.” Moreover, the results of physicochemical analysis are also in consonance with the biological water quality criteria developed by Central Pollution Control Board.

HEMOXCell, a New Oxygen Carrier Usable as an Additive for Mesenchymal Stem Cell Culture in Platelet Lysate-Supplemented Media.

PubMed

Le Pape, Fiona; Cosnuau-Kemmat, Lucie; Richard, Gaëlle; Dubrana, Frédéric; Férec, Claude; Zal, Franck; Leize, Elisabeth; Delépine, Pascal

2017-04-01

Human mesenchymal stem cells (MSCs) are promising candidates for therapeutic applications such as tissue engineering. However, one of the main challenges is to improve oxygen supply to hypoxic areas to reduce oxygen gradient formation while preserving MSC differentiation potential and viability. For this purpose, a marine hemoglobin, HEMOXCell, was evaluated as an oxygen carrier for culturing human bone marrow MSCs in vitro for future three-dimensional culture applications. Impact of HEMOXCell on cell growth and viability was assessed in human platelet lysate (hPL)-supplemented media. Maintenance of MSC features, such as multipotency and expression of MSC specific markers, was further investigated by biochemical assays and flow cytometry analysis. Our experimental results highlight its oxygenator potential and indicate that an optimal concentration of 0.025 g/L HEMOXCell induces a 25%-increase of the cell growth rate, preserves MSC phenotype, and maintains MSC differentiation properties; a two-fold higher concentration induces cell detachment without altering cell viability. Our data suggest the potential interest of HEMOXCell as a natural oxygen carrier for tissue engineering applications to oxygenate hypoxic areas and to maintain cell viability, functions and "stemness." These features will be further tested within three-dimensional scaffolds. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Hollow spheres of iron carbide nanoparticles encased in graphitic layers as oxygen reduction catalysts.

PubMed

Hu, Yang; Jensen, Jens Oluf; Zhang, Wei; Cleemann, Lars N; Xing, Wei; Bjerrum, Niels J; Li, Qingfeng

2014-04-01

Nonprecious metal catalysts for the oxygen reduction reaction are the ultimate materials and the foremost subject for low-temperature fuel cells. A novel type of catalysts prepared by high-pressure pyrolysis is reported. The catalyst is featured by hollow spherical morphologies consisting of uniform iron carbide (Fe3 C) nanoparticles encased by graphitic layers, with little surface nitrogen or metallic functionalities. In acidic media the outer graphitic layers stabilize the carbide nanoparticles without depriving them of their catalytic activity towards the oxygen reduction reaction (ORR). As a result the catalyst is highly active and stable in both acid and alkaline electrolytes. The synthetic approach, the carbide-based catalyst, the structure of the catalysts, and the proposed mechanism open new avenues for the development of ORR catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling☆

PubMed Central

Riethmüller, Michaela; Burger, Nils; Bauer, Georg

2015-01-01

Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2.) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. PMID:26225731

Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling.

PubMed

Riethmüller, Michaela; Burger, Nils; Bauer, Georg

2015-12-01

Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2(.)) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) for prediction of breast cancer chemotherapy response: a pilot study.

PubMed

Jiang, Lan; Weatherall, Paul T; McColl, Roderick W; Tripathy, Debu; Mason, Ralph P

2013-05-01

To determine whether a simple noninvasive method of assessing tumor oxygenation is feasible in the clinical setting and can provide useful, potentially predictive information. Tumor microcirculation and oxygenation play critical roles in tumor growth and responsiveness to cytotoxic treatment and may provide prognostic indicators for cancer therapy. Deoxyhemoglobin is paramagnetic and can serve as an endogenous contrast agent causing signal loss in echo planar magnetic resonance imaging (MRI) (blood oxygenation level-dependent [BOLD]-MRI). We used BOLD-MRI to provide early evaluation of response to neoadjuvant chemotherapy in patients with locally advanced breast cancer. MRI was performed on 11 patients with biopsy-proven malignancy. MRI exams were scheduled before, during, and after chemotherapy. The BOLD study applied a 6-minute oxygen breathing challenge. Seven patients successfully completed the exams. Before chemotherapy, BOLD contrast enhancement was observed in all tumors, but the patients, who ultimately had complete pathological response, exhibited a significantly higher BOLD response to oxygen breathing. We have successfully implemented an oxygen-breathing challenge BOLD contrast technique as part of the standard breast MRI exam in patients with locally advanced breast cancer. The preliminary observation that a large BOLD response correlated with better treatment response suggests a predictive capability for BOLD MRI. Copyright © 2012 Wiley Periodicals, Inc.

Carbon Dioxide Reduction Post-Processing Sub-System Development

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Greenwood, Zachary; Barton, Katherine

2012-01-01

The state-of-the-art Carbon Dioxide (CO2) Reduction Assembly (CRA) on the International Space Station (ISS) facilitates the recovery of oxygen from metabolic CO2. The CRA utilizes the Sabatier process to produce water with methane as a byproduct. The methane is currently vented overboard as a waste product. Because the CRA relies on hydrogen for oxygen recovery, the loss of methane ultimately results in a loss of oxygen. For missions beyond low earth orbit, it will prove essential to maximize oxygen recovery. For this purpose, NASA is exploring an integrated post-processor system to recover hydrogen from CRA methane. The post-processor, called a Plasma Pyrolysis Assembly (PPA) partially pyrolyzes methane to recover hydrogen with acetylene as a byproduct. In-flight operation of post-processor will require a Methane Purification Assembly (MePA) and an Acetylene Separation Assembly (ASepA). Recent efforts have focused on the design, fabrication, and testing of these components. The results and conclusions of these efforts will be discussed as well as future plans.

Controllable positive exchange bias via redox-driven oxygen migration

DOE PAGES

Gilbert, Dustin A.; Olamit, Justin; Dumas, Randy K.; ...

2016-03-21

We report that ionic transport in metal/oxide heterostructures offers a highly effective means to tailor material properties via modification of the interfacial characteristics. However, direct observation of ionic motion under buried interfaces and demonstration of its correlation with physical properties has been challenging. Using the strong oxygen affinity of gadolinium, we design a model system of Gd xFe 1-x/NiCoO bilayer films, where the oxygen migration is observed and manifested in a controlled positive exchange bias over a relatively small cooling field range. The exchange bias characteristics are shown to be the result of an interfacial layer of elemental nickel andmore » cobalt, a few nanometres in thickness, whose moments are larger than expected from uncompensated NiCoO moments. This interface layer is attributed to a redox-driven oxygen migration from NiCoO to the gadolinium, during growth or soon after. Ultimately, these results demonstrate an effective path to tailoring the interfacial characteristics and interlayer exchange coupling in metal/oxide heterostructures.« less

Study of acute biochemical effects of thallium toxicity in mouse urine by NMR spectroscopy.

PubMed

Tyagi, Ritu; Rana, Poonam; Khan, Ahmad Raza; Bhatnagar, Deepak; Devi, M Memita; Chaturvedi, Shubhra; Tripathi, Rajendra P; Khushu, Subash

2011-10-01

Thallium (Tl) is a toxic heavy metal and its exposure to the human body causes physiological and biochemical changes due to its interference with potassium-dependent biological reactions. A high-resolution (1)H NMR spectroscopy based metabonomic approach has been applied for investigating acute biochemical effects caused by thallium sulfate (Tl(2)SO(4)). Male strain A mice were divided in three groups and received three doses of Tl(2)SO(4) (5, 10 and 20 mg kg(-1) b.w., i.p.). Urine samples collected at 3, 24, 72 and 96 h post-dose time points were analyzed by (1)H NMR spectroscopy. NMR spectral data were processed and analyzed using principal components analysis to represent biochemical variations induced by Tl(2)SO(4). Results showed Tl-exposed mice urine to have distinct metabonomic phenotypes and revealed dose- and time-dependent clustering of treated groups. The metabolic signature of urine analysis from Tl(2)SO(4)-treated animals exhibited an increase in the levels of creatinine, taurine, hippurate and β-hydroxybutyrate along with a decrease in energy metabolites trimethylamine and choline. These findings revealed Tl-induced disturbed gut flora, membrane metabolite, energy and protein metabolism, representing physiological dysfunction of vital organs. The present study indicates the great potential of NMR-based metabonomics in mapping metabolic response for toxicology, which could ultimately lead to identification of potential markers for Tl toxicity. Copyright © 2011 John Wiley & Sons, Ltd.

Clinical importance of achieving biochemical control with medical therapy in adult patients with acromegaly

PubMed Central

Christofides, Elena A

2016-01-01

In acromegaly, achieving biochemical control (growth hormone [GH] level <1.0 ng/mL and age- and sex-normalized levels of insulin-like growth factor 1 [IGF-1]) through timely diagnosis and appropriate treatment provides an opportunity to improve patient outcomes. Diagnosis of acromegaly is challenging because it is rooted in observing subtle clinical manifestations, and it is typical for acromegaly to evolve for up to 10 years before it is recognized. This results in chronic exposure to elevated levels of GH and IGF-1 and delay in patients receiving appropriate treatment, which consequently increases mortality risk. In this review, the clinical impact of elevated GH and IGF-1 levels, the effectiveness of current therapies, and the potential role of novel treatments for acromegaly will be discussed. Clinical burden of acromegaly and benefits associated with management of GH and IGF-1 levels will be reviewed. Major treatment paradigms in acromegaly include surgery, medical therapy, and radiotherapy. With medical therapies, such as somatostatin analogs, dopamine agonists, and GH receptor antagonists, a substantial proportion of patients achieve reduced GH and normalized IGF-1 levels. In addition, signs and symptoms, quality of life, and comorbidities have also been reported to improve to varying degrees in patients who achieve biochemical control. Currently, there are several innovative therapies in development to improve patient outcomes, patient use, and access. Timely biochemical control of acromegaly ensures that the patient can ultimately improve morbidity and mortality from this disease and its extensive consequences. PMID:27471378

Acetylcholine Esterase Activity and Behavioral Response in Hypoxia Induced Neonatal Rats: Effect of Glucose, Oxygen and Epinephrine Supplementation

ERIC Educational Resources Information Center

Chathu, Finla; Krishnakumar, Amee; Paulose, Cheramadathikudyil S.

2008-01-01

Brain damage due to an episode of hypoxia remains a major problem in infants causing deficit in motor and sensory function. Hypoxia leads to neuronal functional failure, cerebral palsy and neuro-developmental delay with characteristic biochemical and molecular alterations resulting in permanent or transitory neurological sequelae or even death.…

The Environmental Assessment and Management (TEAM) Guide: Idaho Supplement

DTIC Science & Technology

2010-02-01

rsons u nder common control ). Pollutant-emitting activities shall be considered as part of the same industrial grouping if they belong to the same...area ASTM American Society for Testing and Materials AWWA American Water Works Association BACT best available control technology BOD...biochemical oxygen demand BTEX benzene, toluene, elthylbenzene, xylene CAR control area responsible party CAS Chemical Abstract Service CEM continuous

Hydrologic and water-quality data for the East River Basin in northeastern Wisconsin

USGS Publications Warehouse

Hughes, P.E.

1993-01-01

Mean concentrations for 5-day biochemical oxygen demand, total-phosphorus concentration, fecal-coliform counts, and fecal-streptococcus counts were higher at Bower Creek than any of the other sites monitored during 1985-86. Mean chlorophyll a concentrations were highest at the East River sites at Monroe Street in Green Bay and at Allouez Avenue bridge at Allouez.

Using Yeast to Easily Determine Mitochondrial Functionality with 1-(4,5-Dimethylthiazol-2-yl)-3,5-Diphenyltetrazolium Bromide (MTT) Assay

ERIC Educational Resources Information Center

Sanchez, Norma Silvia; Konigsberg, Mina

2006-01-01

Mitochondrial respiration is an important topic in biochemical courses, but at the same time it is a very arduous and challenging subject for the students to comprehend. In teaching laboratories, experiments are also difficult to perform because mitochondrial isolation as well as oxygen consumption determinations require expensive equipment,…

Missouri River, Natural Resources Bibliography.

DTIC Science & Technology

1997-07-01

Missouri River. South Dakota Cons. Dig. 19- Canadian Society of Petroleum Geologists 23. 9:205-19. Missouri River Bibliography 91 1669. SIMPSON PW...Invertebrates of southwestern North Dakota: Report Number 1, Missouri River main stem, aquatic molluscs . Geology Department, 1958-1962. U.S. Public Health... Bioaccumulation 1404, 1559, 1561 Bottom Features 151 Bank Protection 496, 1320, 1840, Bioassays 337 Bottom Sampling 1164 1869 Biochemical Oxygen

[Molecular mechanisms of protein biosynthesis initiation--biochemical and biomedical implications of a new model of translation enhanced by the RNA hypoxia response element (rHRE)].

PubMed

Master, Adam; Nauman, Alicja

2014-01-01

Translation initiation is a key rate-limiting step in cellular protein synthesis. A cap-dependent initiation is the most effective mechanism of the translation. However, some physiological (mitosis) and pathological (oxidative stress) processes may switch the classic mechanism to an alternative one that is regulated by an mRNA element such as IRES, uORF, IRE, CPE, DICE, AURE or CITE. A recently discovered mechanism of RNA hypoxia response element (rHRE)-dependent translation initiation, may change the view of oxygen-regulated translation and give a new insight into unexplained biochemical processes. Hypoxia is one of the better-known factors that may trigger an alternative mechanism of the translation initiation. Temporal events of oxygen deficiency within tissues and organs may activate processes such as angiogenesis, myogenesis, regeneration, wound healing, and may promote an adaptive response in cardiovascular and neurodegenerative diseases. On the other hand, growth of solid tumors may be accompanied by cyclic hypoxia, allowing for synthesis of proteins required for further progression of cancer cells. This paper provides a review of current knowledge on translational control in the context of alternative models of translation initiation.

Biochemical properties and yields of diverse bacterial laccase-like multicopper oxidases expressed in Escherichia coli

PubMed Central

Ihssen, Julian; Reiss, Renate; Luchsinger, Ronny; Thöny-Meyer, Linda; Richter, Michael

2015-01-01

Laccases are multi-copper oxidases that oxidize a broad range of substrates at the expense of molecular oxygen, without any need for co-factor regeneration. These enzymes bear high potential for the sustainable synthesis of fine chemicals and the modification of (bio)polymers. Here we describe cloning and expression of five novel bacterial laccase-like multi copper oxidases (LMCOs) of diverse origin which were identified by homology searches in online databases. Activity yields under different expression conditions and temperature stabilities were compared to three previously described enzymes from Bacillus subtilis, Bacillus pumilus and Bacillus clausii. In almost all cases, a switch to oxygen-limited growth conditions after induction increased volumetric activity considerably. For proteins with predicted signal peptides for secretion, recombinant expression with and without signal sequence was investigated. Bacillus CotA-type LMCOs outperformed enzymes from Streptomyces and Gram-negative bacteria with respect to activity yields in Escherichia coli and application relevant biochemical properties. The novel Bacillus coagulans LMCO combined high activity yields in E. coli with unprecedented activity at strong alkaline pH and high storage stability, making it a promising candidate for further development. PMID:26068013

An Overview of Seasonal Changes in Oxidative Stress and Antioxidant Defence Parameters in Some Invertebrate and Vertebrate Species.

PubMed

Chainy, Gagan Bihari Nityananda; Paital, Biswaranjan; Dandapat, Jagneswar

2016-01-01

Antioxidant defence system, a highly conserved biochemical mechanism, protects organisms from harmful effects of reactive oxygen species (ROS), a by-product of metabolism. Both invertebrates and vertebrates are unable to modify environmental physical factors such as photoperiod, temperature, salinity, humidity, oxygen content, and food availability as per their requirement. Therefore, they have evolved mechanisms to modulate their metabolic pathways to cope their physiology with changing environmental challenges for survival. Antioxidant defences are one of such biochemical mechanisms. At low concentration, ROS regulates several physiological processes, whereas at higher concentration they are toxic to organisms because they impair cellular functions by oxidizing biomolecules. Seasonal changes in antioxidant defences make species able to maintain their correct ROS titre to take various physiological functions such as hibernation, aestivation, migration, and reproduction against changing environmental physical parameters. In this paper, we have compiled information available in the literature on seasonal variation in antioxidant defence system in various species of invertebrates and vertebrates. The primary objective was to understand the relationship between varied biological phenomena seen in different animal species and conserved antioxidant defence system with respect to seasons.

An Overview of Seasonal Changes in Oxidative Stress and Antioxidant Defence Parameters in Some Invertebrate and Vertebrate Species

PubMed Central

Chainy, Gagan Bihari Nityananda; Paital, Biswaranjan; Dandapat, Jagneswar

2016-01-01

Antioxidant defence system, a highly conserved biochemical mechanism, protects organisms from harmful effects of reactive oxygen species (ROS), a by-product of metabolism. Both invertebrates and vertebrates are unable to modify environmental physical factors such as photoperiod, temperature, salinity, humidity, oxygen content, and food availability as per their requirement. Therefore, they have evolved mechanisms to modulate their metabolic pathways to cope their physiology with changing environmental challenges for survival. Antioxidant defences are one of such biochemical mechanisms. At low concentration, ROS regulates several physiological processes, whereas at higher concentration they are toxic to organisms because they impair cellular functions by oxidizing biomolecules. Seasonal changes in antioxidant defences make species able to maintain their correct ROS titre to take various physiological functions such as hibernation, aestivation, migration, and reproduction against changing environmental physical parameters. In this paper, we have compiled information available in the literature on seasonal variation in antioxidant defence system in various species of invertebrates and vertebrates. The primary objective was to understand the relationship between varied biological phenomena seen in different animal species and conserved antioxidant defence system with respect to seasons. PMID:27127682

Biochemical methane potential tests of different autoclaved and microwaved lignocellulosic organic fractions of municipal solid waste.

PubMed

Pecorini, Isabella; Baldi, Francesco; Carnevale, Ennio Antonio; Corti, Andrea

2016-10-01

The aim of this research was to enhance the anaerobic biodegradability and methane production of two synthetic Organic Fractions of Municipal Solid Waste with different lignocellulosic contents by assessing microwave and autoclave pre-treatments. Biochemical Methane Potential assays were performed for 21days. Changes in the soluble fractions of the organic matter (measured by soluble chemical oxygen demand, carbohydrates and proteins), the first order hydrolysis constant kh and the cumulated methane production at 21days were used to evaluate the efficiency of microwaving and autoclaving pretreatments on substrates solubilization and anaerobic digestion. Microwave treatment led to a methane production increase of 8.5% for both the tested organic fractions while autoclave treatment had an increase ranging from 1.0% to 4.4%. Results showed an increase of the soluble fraction after pre-treatments for both the synthetic organic fractions. Soluble chemical oxygen demand observed significant increases for pretreated substrates (up to 219.8%). In this regard, the mediocre results of methane's production led to the conclusion that autoclaving and microwaving resulted in the hydrolysis of a significant fraction of non-biodegradable organic substances recalcitrant to anaerobic digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Operating Parameters on Measurements of Biochemical Oxygen Demand Using a Mediatorless Microbial Fuel Cell Biosensor.

PubMed

Hsieh, Min-Chi; Cheng, Chiu-Yu; Liu, Man-Hai; Chung, Ying-Chien

2015-12-28

The conventional Biochemical Oxygen Demand (BOD) method takes five days to analyze samples. A microbial fuel cell (MFC) may be an alternate tool for rapid BOD determination in water. However, a MFC biosensor for continuous BOD measurements of water samples is still unavailable. In this study, a MFC biosensor inoculated with known mixed cultures was used to determine the BOD concentration. Effects of important parameters on establishing a calibration curve between the BOD concentration and output signal from the MFC were evaluated. The results indicate monosaccharides were good fuel, and methionine, phenylalanine, and ethanol were poor fuels for electricity generation by the MFC. Ions in the influent did not significantly affect the MFC performance. CN(-) in the influent could alleviate the effect of antagonistic electron acceptors on the MFC performance. The regression equation for BOD concentration and current density of the biosensor was y = 0.0145x + 0.3317. It was adopted to measure accurately and continuously the BOD concentration in actual water samples at an acceptable error margin. These results clearly show the developed MFC biosensor has great potential as an alternative BOD sensing device for online measurements of wastewater BOD.

Potential Role of Selenoenzymes and Antioxidant Metabolism in relation to Autism Etiology and Pathology

PubMed Central

Raymond, Laura J.; Deth, Richard C.; Ralston, Nicholas V. C.

2014-01-01

Autism and autism spectrum disorders (ASDs) are behaviorally defined, but the biochemical pathogenesis of the underlying disease process remains uncharacterized. Studies indicate that antioxidant status is diminished in autistic subjects, suggesting its pathology is associated with augmented production of oxidative species and/or compromised antioxidant metabolism. This suggests ASD may result from defects in the metabolism of cellular antioxidants which maintain intracellular redox status by quenching reactive oxygen species (ROS). Selenium-dependent enzymes (selenoenzymes) are important in maintaining intercellular reducing conditions, particularly in the brain. Selenoenzymes are a family of ~25 genetically unique proteins, several of which have roles in preventing and reversing oxidative damage in brain and endocrine tissues. Since the brain's high rate of oxygen consumption is accompanied by high ROS production, selenoenzyme activities are particularly important in this tissue. Because selenoenzymes can be irreversibly inhibited by many electrophiles, exposure to these organic and inorganic agents can diminish selenoenzyme-dependent antioxidant functions. This can impair brain development, particularly via the adverse influence of oxidative stress on epigenetic regulation. Here we review the physiological roles of selenoproteins in relation to potential biochemical mechanisms of ASD etiology and pathology. PMID:24734177

Predicting influent biochemical oxygen demand: Balancing energy demand and risk management.

PubMed

Zhu, Jun-Jie; Kang, Lulu; Anderson, Paul R

2018-01-01

Ready access to comprehensive influent information can help water reclamation plant (WRP) operators implement better real-time process controls, provide operational reliability and reduce energy consumption. The five-day biochemical oxygen demand (BOD 5 ), a critical parameter for WRP process control, is expensive and difficult to measure using hard-sensors. An alternative approach based on a soft-sensor methodology shows promise, but can be problematic when used to predict high BOD 5 values. Underestimating high BOD 5 concentrations for process control could result in an insufficient amount of aeration, increasing the risk of an effluent violation. To address this issue, we tested a hierarchical hybrid soft-sensor approach involving multiple linear regression, artificial neural networks (ANN), and compromise programming. While this hybrid approach results in a slight decrease in overall prediction accuracy relative to the approach based on ANN only, the underestimation percentage is substantially lower (37% vs. 61%) for predictions of carbonaceous BOD 5 (CBOD 5 ) concentrations higher than the long-term average value. The hybrid approach is also flexible and can be adjusted depending on the relative importance between energy savings and managing the risk of an effluent violation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein and DNA Modifications: Evolutionary Imprints of Bacterial Biochemical Diversification and Geochemistry on the Provenance of Eukaryotic Epigenetics

PubMed Central

Aravind, L.; Burroughs, A. Maxwell; Zhang, Dapeng; Iyer, Lakshminarayan M.

2014-01-01

Epigenetic information, which plays a major role in eukaryotic biology, is transmitted by covalent modifications of nuclear proteins (e.g., histones) and DNA, along with poorly understood processes involving cytoplasmic/secreted proteins and RNAs. The origin of eukaryotes was accompanied by emergence of a highly developed biochemical apparatus for encoding, resetting, and reading covalent epigenetic marks in proteins such as histones and tubulins. The provenance of this apparatus remained unclear until recently. Developments in comparative genomics show that key components of eukaryotic epigenetics emerged as part of the extensive biochemical innovation of secondary metabolism and intergenomic/interorganismal conflict systems in prokaryotes, particularly bacteria. These supplied not only enzymatic components for encoding and removing epigenetic modifications, but also readers of some of these marks. Diversification of these prokaryotic systems and subsequently eukaryotic epigenetics appear to have been considerably influenced by the great oxygenation event in the Earth’s history. PMID:24984775

Protein and DNA modifications: evolutionary imprints of bacterial biochemical diversification and geochemistry on the provenance of eukaryotic epigenetics.

PubMed

Aravind, L; Burroughs, A Maxwell; Zhang, Dapeng; Iyer, Lakshminarayan M

2014-07-01

Epigenetic information, which plays a major role in eukaryotic biology, is transmitted by covalent modifications of nuclear proteins (e.g., histones) and DNA, along with poorly understood processes involving cytoplasmic/secreted proteins and RNAs. The origin of eukaryotes was accompanied by emergence of a highly developed biochemical apparatus for encoding, resetting, and reading covalent epigenetic marks in proteins such as histones and tubulins. The provenance of this apparatus remained unclear until recently. Developments in comparative genomics show that key components of eukaryotic epigenetics emerged as part of the extensive biochemical innovation of secondary metabolism and intergenomic/interorganismal conflict systems in prokaryotes, particularly bacteria. These supplied not only enzymatic components for encoding and removing epigenetic modifications, but also readers of some of these marks. Diversification of these prokaryotic systems and subsequently eukaryotic epigenetics appear to have been considerably influenced by the great oxygenation event in the Earth's history. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Berkeley extreme-ultraviolet airglow rocket spectrometer - BEARS

NASA Technical Reports Server (NTRS)

Cotton, D. M.; Chakrabarti, S.

1992-01-01

The Berkeley EUV airglow rocket spectrometer (BEARS) instrument is described. The instrument was designed in particular to measure the dominant lines of atomic oxygen in the FUV and EUV dayglow at 1356, 1304, 1027, and 989 A, which is the ultimate source of airglow emissions. The optical and mechanical design of the instrument, the detector, electronics, calibration, flight operations, and results are examined.

Comparative TEA for Indirect Liquefaction Pathways to Distillate-Range Fuels via Oxygenated Intermediates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Eric; Snowden-Swan, Lesley J.; Talmadge, Michael

This paper presents a comparative techno-economic analysis of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates (derived either via thermochemical or biochemical conversion steps). The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass-to-syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates, followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. We show that the emerging pathways via oxygenated intermediatesmore » have the potential to be cost competitive with the conventional Fischer-Tropsch process. The evaluated pathways and the benchmark process generally exhibit similar fuel yields and carbon conversion efficiencies. The resulting minimum fuel selling prices are comparable to the benchmark at approximately $3.60 per gallon-gasoline equivalent, with potential for two new pathways to be more economically competitive. Additionally, the coproduct values can play an important role in the economics of the processes with oxygenated intermediates derived via syngas fermentation. Major cost drivers for the integrated processes are tied to achievable fuel yields and conversion efficiency of the intermediate steps, i.e., the production of oxygenates/alcohols from syngas and the conversion of oxygenates/alcohols to hydrocarbon fuels.« less

Blood gas and serum biochemical RIs for healthy newborn Murrah buffaloes (Bubalus bubalis).

PubMed

Santana, André M; Silva, Daniela G; Clemente, Virna; Pizauro, Lucas J L; Bernardes, Priscila A; Santana, Clarissa H; Eckersall, Peter D; Fagliari, José J

2018-03-01

There is a lack of published work on RIs for newborn buffaloes. Establishing blood gas and serum biochemical RIs for newborn buffaloes is important for monitoring health. This study establishes blood gas and serum biochemical RIs of newborn buffaloes. Twenty-eight newborn buffaloes, 10-30 days old, were selected. Thirty blood biochemical variables were analyzed. The Anderson-Darling test was used to assess the normality of the distribution. The Dixon test and the Tukey test were used to identify outliers. The RI and 90% CI were determined using standard and robust methods and the Box-Cox transformation. A total of 30 RIs for healthy buffalo calves have been reported in this study. RIs for blood gas variables were reported for pH, partial pressure of oxygen (pO 2 ), partial pressure of carbon dioxide (pCO 2 ), saturation of O 2 (SO 2 ), bicarbonate (cHCO 3 - ), base excess (BE), total carbon dioxide (ctCO 2 ), and anion gap (AG). RIs for serum biochemical variables were reported for glucose (GLU), direct bilirubin (DB), total bilirubin (TB), AST, ALP, GGT, CK, LDH, creatinine (CREA), urea, cholesterol (CHOL), triglycerides (TG), Ca, P, Mg, Na, K, iCa, Cl, iron, total protein (TP), and albumin (ALB). This is the first reported study covering complete serum chemistry and blood gas RIs for healthy 1-month-old Murrah buffaloes. © 2018 American Society for Veterinary Clinical Pathology.

Characterization of oxidative phosphorylation enzymes in Euglena gracilis and its white mutant strain W(gm)ZOflL.

PubMed

Krnáčová, Katarína; Rýdlová, Ivana; Vinarčíková, Michaela; Krajčovič, Juraj; Vesteg, Matej; Horváth, Anton

2015-03-12

The enzymes involved in Euglena oxidative phosphorylation (OXPHOS) were characterized in this study. We have demonstrated that Euglena gracilis strain Z and its stable bleached non-photosynthetic mutant strain WgmZOflL both possess fully functional OXPHOS apparatus as well as pathways requiring terminal alternative oxidase(s) and alternative mitochondrial NADH-dehydrogenase(s). Light (or dark) and plastid (non)functionality seem to have little effect on oxygen consumption, the activities of the enzymes involved in OXPHOS and the action of respiration inhibitors in Euglena. This study also demonstrates biochemical properties of complex III (cytochrome c reductase) in Euglena. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Lego bricks and the octet rule: Molecular models for biochemical pathways with plastic, interlocking toy bricks.

PubMed

Lin, Henry J; Lehoang, Jennifer; Kwan, Isabel; Baghaee, Anita; Prasad, Priya; Ha-Chen, Stephanie J; Moss, Tanesha; Woods, Jeremy D

2018-01-01

The 8 studs on a 2 × 4 Lego brick conveniently represent the outer shell of electrons for carbon, nitrogen, and oxygen atoms. We used Lego bricks to model these atoms, which are then joined together to form molecules by following the Lewis octet rule. A variety of small biological molecules can be modeled in this way, such as most amino acids, fatty acids, glucose, and various intermediate metabolites. Model building with these familiar toys can be a helpful, hands-on exercise for learning-or re-learning-biochemical pathways. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):54-57, 2018. © 2017 The International Union of Biochemistry and Molecular Biology.

Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry

NASA Astrophysics Data System (ADS)

Pogue, Brian W.; Paulsen, Keith D.; O'Hara, Julia A.; Hoopes, P. Jack; Swartz, Harold

2000-03-01

Photodynamic theory of tumors uses optical excitation of a sensitizing drug within tissue to produce large deposits of singlet oxygen, which are thought to ultimately cause the tumor destruction. Predicting dose deposition of singlet oxygen in vivo is challenging because measurement of this species in vivo is not easily achieved. But it is possible to follow the concentration of oxygen in vivo, and so measuring the oxygen concentration transients during PDT may provide a viable method of estimating the delivered dose of singlet oxygen. However modeling the microscopic heterogeneity of the oxygen distribution within a tumor is non-trivial, and predicting the microscopic dose deposition requires further study, but this study present the framework and initial calibration needed or modeling oxygen transport in complex geometries. Computational modeling with finite elements provides a versatile structure within which oxygen diffusion and consumption can be modeled within realistic tissue geometries. This study develops the basic tools required to simulate a tumor region, and examines the role of (i) oxygen supply and consumption rates, (ii) inter- capillary spacing, (iii) photosensitizer distribution, and (iv) differences between simulated tumors and those derived directly from histology. The result of these calculations indicate that realistic tumor tissue capillary networks can be simulated using the finite element method, without excessive computational burden for 2D regions near 1 mm2, and 3D regions near 0.1mm3. These simulations can provide fundamental information about tissue and ways to implement appropriate oxygen measurements. These calculations suggest that photodynamic therapy produces the majority of singlet oxygen in and near the blood vessels, because these are the sites of highest oxygen tension. These calculations support the concept that tumor vascular regions are the major targets for PDT dose deposition.

Characterizing autism spectrum disorders by key biochemical pathways.

PubMed

Subramanian, Megha; Timmerman, Christina K; Schwartz, Joshua L; Pham, Daniel L; Meffert, Mollie K

2015-01-01

The genetic and phenotypic heterogeneity of autism spectrum disorders (ASD) presents a substantial challenge for diagnosis, classification, research, and treatment. Investigations into the underlying molecular etiology of ASD have often yielded mixed and at times opposing findings. Defining the molecular and biochemical underpinnings of heterogeneity in ASD is crucial to our understanding of the pathophysiological development of the disorder, and has the potential to assist in diagnosis and the rational design of clinical trials. In this review, we propose that genetically diverse forms of ASD may be usefully parsed into entities resulting from converse patterns of growth regulation at the molecular level, which lead to the correlates of general synaptic and neural overgrowth or undergrowth. Abnormal brain growth during development is a characteristic feature that has been observed both in children with autism and in mouse models of autism. We review evidence from syndromic and non-syndromic ASD to suggest that entities currently classified as autism may fundamentally differ by underlying pro- or anti-growth abnormalities in key biochemical pathways, giving rise to either excessive or reduced synaptic connectivity in affected brain regions. We posit that this classification strategy has the potential not only to aid research efforts, but also to ultimately facilitate early diagnosis and direct appropriate therapeutic interventions.

Characterizing autism spectrum disorders by key biochemical pathways

PubMed Central

Subramanian, Megha; Timmerman, Christina K.; Schwartz, Joshua L.; Pham, Daniel L.; Meffert, Mollie K.

2015-01-01

The genetic and phenotypic heterogeneity of autism spectrum disorders (ASD) presents a substantial challenge for diagnosis, classification, research, and treatment. Investigations into the underlying molecular etiology of ASD have often yielded mixed and at times opposing findings. Defining the molecular and biochemical underpinnings of heterogeneity in ASD is crucial to our understanding of the pathophysiological development of the disorder, and has the potential to assist in diagnosis and the rational design of clinical trials. In this review, we propose that genetically diverse forms of ASD may be usefully parsed into entities resulting from converse patterns of growth regulation at the molecular level, which lead to the correlates of general synaptic and neural overgrowth or undergrowth. Abnormal brain growth during development is a characteristic feature that has been observed both in children with autism and in mouse models of autism. We review evidence from syndromic and non-syndromic ASD to suggest that entities currently classified as autism may fundamentally differ by underlying pro- or anti-growth abnormalities in key biochemical pathways, giving rise to either excessive or reduced synaptic connectivity in affected brain regions. We posit that this classification strategy has the potential not only to aid research efforts, but also to ultimately facilitate early diagnosis and direct appropriate therapeutic interventions. PMID:26483618

Biochemical responses to dietary α-linolenic acid restriction proceed differently among brain regions in mice.

PubMed

Miyazawa, Daisuke; Yasui, Yuko; Yamada, Kazuyo; Ohara, Naoki; Okuyama, Harumi

2011-08-01

Previously, we noted that the dietary restriction of α-linolenic acid (ALA, n-3) for 4 weeks after weaning brought about significant decreases in the BDNF content and p38 MAPK activity in the striatum of mice, but not in the other regions of the brain, compared with an ALA- and linoleic acid (LNA, n-6)-adequate diet. In this study, we examined whether a prolonged dietary manipulation induces biochemical changes in other regions of the brain as well. Mice were fed a safflower oil (SAF) diet (ALA-restricted, LNA-adequate) or a perilla oil (PER) diet (containing adequate amounts of ALA and LNA) for 8 weeks from weaning. The docosahexaenoic acid (DHA, 22:6n-3) contents and p38 MAPK activities in the cerebral cortex, striatum and hippocampus were significantly lower in the SAF group. The BDNF contents and protein kinase C (PKC) activities in the cerebral cortex as well as in the striatum, but not in the hippocampus, were significantly lower in the SAF group. These data indicate that the biochemical changes induced by the dietary restriction of ALA have a time lag in the striatum and cortex, suggesting that the signal is transmitted through decreased p38 MAPK activity and BDNF content and ultimately decreased PKC activity.

The WAVE2 Complex Regulates Actin Cytoskeletal Reorganization and CRAC-Mediated Calcium Entry during T Cell Activation

PubMed Central

Nolz, Jeffrey C.; Gomez, Timothy S.; Zhu, Peimin; Li, Shuixing; Medeiros, Ricardo B.; Shimizu, Yoji; Burkhardt, Janis K.; Freedman, Bruce D.; Billadeau, Daniel D.

2007-01-01

Summary Background The engagement of the T cell receptor results in actin cytoskeletal reorganization at the immune synapse (IS) and the triggering of biochemical signaling cascades leading to gene regulation and, ultimately, cellular activation. Recent studies have identified the WAVE family of proteins as critical mediators of Rac1-induced actin reorganization in other cell types. However, whether these proteins participate in actin reorganization at the IS or signaling pathways in T cells has not been investigated. Results By using a combination of biochemical, genetic, and cell biology approaches, we provide evidence that WAVE2 is recruited to the IS, is biochemically modified, and is required for actin reorganization and β-integrin-mediated adhesion after TCR crosslinking. Moreover, we show that WAVE2 regulates calcium entry at a point distal to PLCγ1 activation and IP3-mediated store release. Conclusions These data reveal a role for WAVE2 in regulating multiple pathways leading to T cell activation. In particular, this work shows that WAVE2 is a key component of the actin regulatory machinery in T cells and that it also participates in linking intracellular calcium store depletion to calcium release-activated calcium (CRAC) channel activation. PMID:16401421

Biochemical methane potential (BMP) of agro-food wastes from the Cider Region (Spain).

PubMed

Nieto, P P; Hidalgo, D; Irusta, R; Kraut, D

2012-01-01

An inventory of agro-food industry organic waste streams with a high potential for biogas transformation was studied in a logistically viable area (Cider Region, Asturias, Spain). Three industries were selected as the most viable ones: livestock, dairy and beverage. The potential for methane production from six wastes (beverage waste, BW; milled apple waste, MA; milk waste, MK; yogurt waste, YG; fats and oils from dairy wastewater treatment, F&O and cattle manure, CM) at five different substrate:inoculum ratios (0.25, 0.50, 0.75, 1.00 and 1.50) was evaluated in laboratory batch assays. Obtained methane yields ranged from 202-549 mL STP CH(4)·g VS waste(-1), and the methane content in biogas ranged from 58-76%. The ultimate practical biochemical methane potentials were slightly affected by the substrate:inoculum ratio. The estimation of the regional fluxes of waste and methane potentials suggests anaerobic digestion as a sustainable solution for the valorization of the organic wastes generated in this Region.

Biochemical and molecular aspects of mammalian susceptibility to aflatoxin B{sub 1} carcinogenicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massey, T.E.; Stewart, R.K.; Daniels, J.M.

Aflatoxin B{sub 1} (AFB{sub 1}) is a fungal toxin that has been implicated as a causative agent in human hepatic and extrahepatic carcinogenesis. In this review, the mechanisms involved in AFB{sub 1} toxicity are delineated, in order to describe the features that make a specific cell, tissue, or species susceptible to the mycotoxin. Important considerations include: (i) different mechanisms for bioactivation of AFB{sub 1} to its ultimate carcinogenic epoxide metabolite; (ii) the balance between bioactivation to and detoxification of the epoxide; (iii) the interaction of AFB{sub 1} epoxide with DNA and the mutational events leading to neoplastic transformation; (iv) themore » role of cytotoxicity in AFB{sub 1} carcinogenesis; (v) the significance of nonepoxide metabolites in toxicity; and (vi) the contribution of mycotoxin-unrelated disease processes. Although considerable controversy remains about the importance of specific events, a great deal has been learned about biochemical and molecular actions of AFB{sub 1}. 157 refs., 4 figs., 1 tab.« less

Impact of urban and industrial effluents on the coastal marine environment in Oran, Algeria.

PubMed

Tayeb, A; Chellali, M R; Hamou, A; Debbah, S

2015-09-15

In Algeria most of the urban waste water is dumped without treatment into the Sea. It is tremendously important to assess the consequences of organic matter rich sewage on marine ecosystem. In this study we investigated the effects of industrial and urban sewage on the dissolved oxygen (O2), chemical oxygen demand (COD), biochemical oxygen demands (BOD5), pH, salinity, electrical conductivity (EC), Metal element (Hg, Pb, Cu, Ni, Cr, Cd), petroleum hydrocarbons (HC), oil and grease (OG) in Bay of Oran, Algeria. A ten-year follow-up research showed that the concentrations of oil and grease released into the bionetwork are of higher ecological impact and this needs to be given the desired consideration. Information on bathing water quality revealed that the most beaches in Oran are under the national environmental standard limit. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of selected methods of remote sensing for detecting carbonaceous water pollution

NASA Technical Reports Server (NTRS)

Davis, E. M.; Fosbury, W. J.

1973-01-01

A reach of the Houston Ship Channel was investigated during three separate overflights correlated with ground truth sampling on the Channel. Samples were analyzed for such conventional parameters as biochemical oxygen demand, chemical oxygen demand, total organic carbon, total inorganic carbon, turbidity, chlorophyll, pH, temperature, dissolved oxygen, and light penetration. Infrared analyses conducted on each sample included reflectance ATR analysis, carbon tetrachloride extraction of organics and subsequent scanning, and KBr evaporate analysis of CCl4 extract concentrate. Imagery which was correlated with field and laboratory data developed from ground truth sampling included that obtained from aerial KA62 hardware, RC-8 metric camera systems, and the RS-14 infrared scanner. The images were subjected to analysis by three film density gradient interpretation units. Data were then analyzed for correlations between imagery interpretation as derived from the three instruments and laboratory infrared signatures and other pertinent field and laboratory analyses.

Microbial mats and the early evolution of life

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1990-01-01

Microbial mats have descended from perhaps the oldest and most widespread biological communities known. Mats harbor microbes that are crucial for studies of bacterial phylogeny and physiology. They illustrate how several oxygen-sensitive biochemical processes have adapted to oxygen, and they show how life adapted to dry land long before the rise of plants. The search for the earliest grazing protists and metazoa in stromatolites is aided by observations of mats: in them, organic compounds characteristic of ancient photosynthetic protists can be identified. Recent mat studies suggest that the 13C/12C increase observed over geological time in stromatolitic organic matter was driven at least in part by a long-term decline in atmospheric carbon dioxide levels.

Blood biochemical and cellular changes during a decompression procedure involving eight hours of oxygen prebreathing

NASA Technical Reports Server (NTRS)

Jauchem, J. R.

1989-01-01

Chemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 8 h of oxygen prebreathing. The exposure was designed to simulate space-flight extravehicular activity (EVA) for 6 h. Several statistically significant changes in blood parameters were observed following the exposure: increases in calcium, magnesium, osmolality, low-density lipoprotein cholesterol, monocytes, and prothrombin time, and decreases in chloride, creatine phosphokinase and eosinophils. The changes, however, were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression profile used in this study is not likely to result in blood changes that would pose a threat to astronauts during EVA.

Earth history. Low mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals.

PubMed

Planavsky, Noah J; Reinhard, Christopher T; Wang, Xiangli; Thomson, Danielle; McGoldrick, Peter; Rainbird, Robert H; Johnson, Thomas; Fischer, Woodward W; Lyons, Timothy W

2014-10-31

The oxygenation of Earth's surface fundamentally altered global biogeochemical cycles and ultimately paved the way for the rise of metazoans at the end of the Proterozoic. However, current estimates for atmospheric oxygen (O2) levels during the billion years leading up to this time vary widely. On the basis of chromium (Cr) isotope data from a suite of Proterozoic sediments from China, Australia, and North America, interpreted in the context of data from similar depositional environments from Phanerozoic time, we find evidence for inhibited oxidation of Cr at Earth's surface in the mid-Proterozoic (1.8 to 0.8 billion years ago). These data suggest that atmospheric O2 levels were at most 0.1% of present atmospheric levels. Direct evidence for such low O2 concentrations in the Proterozoic helps explain the late emergence and diversification of metazoans. Copyright © 2014, American Association for the Advancement of Science.

Ultrasonic pretreatment effects on the co-pyrolysis of municipal solid waste and paper sludge through orthogonal test.

PubMed

Fang, Shiwen; Gu, Wenlu; Chen, Lin; Yu, Zhaosheng; Dai, Minquan; Lin, Yan; Liao, Yanfen; Ma, Xiaoqian

2018-06-01

In this study, the influences of ultrasonic pretreatment factors (frequency, power, treatment time) on blends of municipal solid waste (MSW) and paper sludge (PS) with additive (MgO) was explored, through orthogonal experiments design. The optimum operating condition wanted to be acquired. However, for the ultimate (H/C) and ash analysis after pretreatment, solid residue mass and oxygenates compounds contents in products, the influences of factors were in different results. With adding PS unceasingly, the contents of hydrocarbon compounds decreased. And the ultrasonic pretreatment had the obvious influence with high PS percentage. Longer treatment time resulted to the lower content of oxygenates compounds. After adding MgO, the residue mass reduced, which meant MgO had the catalytic action, and the oxygenates compounds content reduced only with 100 kHz, which had the sonochemical effect. Copyright © 2018 Elsevier Ltd. All rights reserved.

AC impedance study of degradation of porous nickel battery electrodes

NASA Technical Reports Server (NTRS)

Lenhart, Stephen J.; Macdonald, D. D.; Pound, B. G.

1987-01-01

AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

40 CFR Appendix B to Subpart E of... - Federal Guidelines-User Charges for Operation and Maintenance of Publicly Owned Treatment Works

Code of Federal Regulations, 2010 CFR

2010-07-01

... characteristics; i.e., levels of biochemical oxygen demand, suspended solids, etc. Each class is then assigned its... works. Factors such as strength, volume, and delivery flow rate characteristics shall be considered and... user charges can be developed on a volume basis in accordance with the model below: Cu = CT/VT(Vu) (2...

Environmental Review for the CV-22 Beddown at Yokota Air Base, Japan

DTIC Science & Technology

2015-02-24

3-7 (U) Figure 3-5. Low-Frequency Noise Effects Thresholds Developed by the Okinawa...Strike Hazard (U) Bgs below ground surface (U) BMPs Best Management Practices (U) BOD Biochemical Oxygen Demand (U) BOE Board of Education. (U) BWC...Noise Equivalent Level (U) CO carbon monoxide (U) CONUS Continental United States (U) CTIT Turbine Inlet Temperature , in degrees Celsius (U) CVW-5

Selected soil enzyme activities in an oak-hickory forest following long-term prescribed burning

Treesearch

M. R. Bayan; F. Eivazi

1993-01-01

The biochemical reactions within the soil are mediated by soil flora and fauna, and are catalyzed by enzymes. Therefore, enzymes play a significant role in nutrient cycling. Enzymes are specific for the type of chemical reactions in which they participate. Arylsulfatase is the enzyme that catalyzes the hydrolysis of an arylsulfate anion by fission of the oxygen-sulfur...

Statistical, graphical, and trend summaries of selected water-quality and streamflow data from the Trinity River near Crockett, Texas, 1964-85

USGS Publications Warehouse

Goss, Richard L.

1987-01-01

As part of the statistical summaries, trend tests were conducted. Several small uptrends were detected for total nitrogen, total organic nitrogen, total ammonia nitrogen, total nitrite nitrogen, total nitrate nitrogen, total organic plus ammonia nitrogen, total nitrite plus nitrate nitrogen, and total phosphorus. Small downtrends were detected for biochemical oxygen demand and dissolved magnesium.

Paraquat toxicity. (Latest citations from the Life Sciences Collection database). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The bibliography contains citations concerning the toxic effects of the herbicide paraquat on humans and animals. Topics include clinical and pathological findings, biochemical mechanisms, effects of oxygen, pulmonary effects of exposure, and effects on freshwater and marine organisms. The contamination of marijuana plants with paraquat is also considered. (Contains 250 citations and includes a subject term index and title list.)

Time-dependent morphological and biochemical changes following cutaneous thermal burn injury and their modulation by copper nicotinate complex: an animal model.

PubMed

Nassar, Muammar A Y; Eldien, Heba M Saad; Tawab, Hanem S Abdel; Saleem, Tahia H; Omar, Hossam M; Nassar, Ahmed Y; Hussein, Mahmoud Rezk Abdelwahed

2012-10-01

Thermal tissue injury is partly mediated by reactive oxygen metabolites. Oxygen free radicals are contributory to local tissue damage following thermal injury and accordingly an interventional therapy using antioxidants may be beneficial. Copper nicotinate complex can scavenge reactive oxygen species (i.e., has antioxidant activity). To examine time-related morphological and biochemical changes following skin thermal injury and their modulation by copper nicotinate complex. An animal model composed of 80 albino rats was established. Ten rats (nonburn group) served as a control group. Seventy rats (burn group) were anesthetized, given a 10% total body surface area, full-thickness burn. Ten rats (from the postburn group) were sacrificed after 24 h (without treatment, i.e., untreated-burn group). The remaining rats were divided into three subgroups (20 rats, each) and were treated topically either with soft paraffin, moist exposed burn ointment (MEBO, a standard therapeutic treatment for burns), or copper nicotinate complex. Five animals from each subgroup were sacrificed every week over a period of 4 weeks. The morphological and biochemical changes were evaluated and compared among the different groups. High levels of the plasma and skin nitiric oxide (marker of oxidative stress) were observed in the untreated-burn group. These levels were significantly low following the application of copper nicotinate complex. Low levels of plasma and skin superoxide dismutase (marker of oxidative stress) and plasma ceruloplasmin were observed in the untreated-burn group. These levels were significantly high following copper nicotinate complex treatment. The total and differential leukocyte counts were low following the onset of the thermal injury. They gradually returned to normal levels over a 4-week period following the application of MEBO or copper nicotinate complex. Compared to untreated-burn group, postburn-healing changes (resolution of the inflammatory reaction, reepithelization of the epidermis, angiogenesis, deposition of collagen fibers, and recovery of the subcellualr organelles) were significantly accelerated following the application of either MEBO or copper nicotinate complex. Application of copper nicotinate complex was associated with improved healing of the thermal burns of the skin. The underlying molecular changes underlying these effects await further investigations.

Isotope excursions and shifting oxidation states recorded in the Paleoproterozoic Franceville Basin

NASA Astrophysics Data System (ADS)

Wang, V.; Junium, C. K.; Lu, Z.; Préat, A.

2014-12-01

Geochemical studies of Paleoproterozoic rocks have revealed that the initial rise of oxygen was protracted and that Earth's surface environments fluctuated between oxic and anoxic states over hundreds of millions of years. Marine sediments of the 2.1 Gyr-old Franceville Basin of west central Africa are only lightly metamorphosed, and their geochemistry may thus reveal unique insights into the environmental and metabolic conditions during the history of rising oxygen levels. In the Franceville Basin stratigraphic variation totaling 10‰ in δ13Ccarb was previously documented. This contribution builds on this work and characterizes changes in C, N, and S cycles using stable isotope values. The results from systematic analysis of several biologically mediated redox proxies preserved in carbonates from the Franceville Basin will be presented, including δ34S values of pyrite and δ13C and δ15N values of bulk organic carbon and kerogens. Consistent with independent reports of an excursion in δ13Corg in the Franceville Basin and elsewhere, we find ~20‰ stratigraphic variation in δ13C of bulk organic carbon. Initial results for δ15N of bulk organic matter range from -6 to 6 ‰, a wider distribution of values than previously reported for the Franceville Basin and more negative than values reported for the similarly aged Onega Basin in Fennoscandia. I/Ca ratios range from near zero to near Phanerozoic levels and are consistent with the presence of iodate. Chromium reducible sulfide has been extracted from all but one sample, confirming the presence of pyrite. δ34S of pyrite as well as δ13C and δ15N of kerogen will also be presented. The biochemically diverse array of proxy analyses presented here have varying thresholds of sensitivity to oxygen levels and hence will allow detailed reconstruction of the redox history of basin waters. As minimum O2 thresholds are often needed for certain biochemical processes, the resulting data will also have implications for key steps in the evolution of biochemical pathways.

Island morphology statistics and growth mechanism for oxidation of the Al(111) surface with thermal O2 and NO

NASA Astrophysics Data System (ADS)

Sexton, J. Z.; Kummel, A. C.

2004-10-01

Scanning tunneling microscopy (STM) was employed to study the mechanism for the oxidation of Al(111) with thermal O2 and NO in the 20%-40% monolayer coverage regime. Experiments show that the islands formed upon exposure to thermal O2 and NO have dramatically different shapes, which are ultimately dictated by the dynamics of the gas surface interaction. The circumference-to-area ratio and other island morphology statistics are used to quantify the average difference in the two island types. Ultrahigh-vacuum STM was employed to make the following observations: (1) Oxygen islands on the Al(111) surface, formed upon exposure to thermal oxygen, are elongated and noncompact. (2) Mixed O/N islands on the Al(111) surface, formed upon exposure to thermal nitric oxide (NO), are round and compact. (3) STM movies acquired during thermal O2 exposure indicate that a complex mechanism involving chemisorption initiated rearrangement of preexisting oxygen islands leads to the asymmetric and elongated island shapes. The overall mechanism for the oxidation of the Al(111) surface can be summarized in three regimes. Low coverage is dominated by widely isolated small oxygen features (<3 O atoms) where normal dissociative chemisorption and oxygen abstraction mechanisms are present. At 20%-40% monolayer coverage, additional oxygen chemisorption induces rearrangement of preexisting islands to form free-energy minimum island shapes. At greater than ˜40% monolayer coverage, the apparent surface oxygen coverage asymptotes corresponding to the conversion of the 2D islands to 3D Al2O3 surface crystallites. The rearrangement of oxygen islands on the surface to form the observed islands indicates that there is a short-range oxygen-oxygen attractive potential and a long-range oxygen-oxygen repulsive potential.

Integrated Application of Multivariate Statistical Methods to Source Apportionment of Watercourses in the Liao River Basin, Northeast China

PubMed Central

Chen, Jiabo; Li, Fayun; Fan, Zhiping; Wang, Yanjie

2016-01-01

Source apportionment of river water pollution is critical in water resource management and aquatic conservation. Comprehensive application of various GIS-based multivariate statistical methods was performed to analyze datasets (2009–2011) on water quality in the Liao River system (China). Cluster analysis (CA) classified the 12 months of the year into three groups (May–October, February–April and November–January) and the 66 sampling sites into three groups (groups A, B and C) based on similarities in water quality characteristics. Discriminant analysis (DA) determined that temperature, dissolved oxygen (DO), pH, chemical oxygen demand (CODMn), 5-day biochemical oxygen demand (BOD5), NH4+–N, total phosphorus (TP) and volatile phenols were significant variables affecting temporal variations, with 81.2% correct assignments. Principal component analysis (PCA) and positive matrix factorization (PMF) identified eight potential pollution factors for each part of the data structure, explaining more than 61% of the total variance. Oxygen-consuming organics from cropland and woodland runoff were the main latent pollution factor for group A. For group B, the main pollutants were oxygen-consuming organics, oil, nutrients and fecal matter. For group C, the evaluated pollutants primarily included oxygen-consuming organics, oil and toxic organics. PMID:27775679

Hypoxic Regulation of Functional Extracellular Matrix Elaboration by Nucleus Pulposus Cells in Long-Term Agarose Culture

PubMed Central

Gorth, Deborah J; Lothstein, Katherine E; Chiaro, Joseph A; Farrell, Megan J; Dodge, George R; Elliott, Dawn M; Malhotra, Neil R; Mauck, Robert L; Smith, Lachlan J

2015-01-01

Degeneration of the intervertebral discs is strongly implicated as a cause of low back pain. Since current treatments for discogenic low back pain show poor long-term efficacy, a number of new, biological strategies are being pursued. For such therapies to succeed, it is critical that they be validated in conditions that mimic the unique biochemical microenvironment of the nucleus pulposus (NP), which include low oxygen tension. Therefore, the objective of this study was to investigate the effects of oxygen tension on NP cell functional extracellular matrix elaboration in 3D culture. Bovine NP cells were encapsulated in agarose constructs and cultured for 14 or 42 days in either 20% or 2% oxygen in defined media containing transforming growth factor beta-3. At each time point, extracellular matrix composition, biomechanics and mRNA expression of key phenotypic markers were evaluated. Results showed that while bulk mechanics and composition were largely independent of oxygen level, low oxygen promoted improved restoration of the NP phenotype, higher mRNA expression of extracellular matrix and NP specific markers, and more uniform matrix elaboration. These findings indicate that culture under physiological oxygen levels is an important consideration for successful development of cell and growth factor-based regenerative strategies for the disc. PMID:25640328

Acute oxygen therapy: a review of prescribing and delivery practices

PubMed Central

Cousins, Joyce L; Wark, Peter AB; McDonald, Vanessa M

2016-01-01

Oxygen is a commonly used drug in the clinical setting and like other drugs its use must be considered carefully. This is particularly true for those patients who are at risk of type II respiratory failure in whom the risk of hypercapnia is well established. In recent times, several international bodies have advocated for the prescription of oxygen therapy in an attempt to reduce this risk in vulnerable patient groups. Despite this guidance, published data have demonstrated that there has been poor uptake of these recommendations. Multiple interventions have been tested to improve concordance, and while some of these interventions show promise, the sustainability of these interventions are less convincing. In this review, we summarize data that have been published on the prevalence of oxygen prescription and the accurate and appropriate administration of this drug therapy. We also identify strategies that have shown promise in facilitating changes to oxygen prescription and delivery practice. There is a clear need to investigate the barriers, facilitators, and attitudes of clinicians in relation to the prescription of oxygen therapy in acute care. Interventions based on these findings then need to be designed and tested to facilitate the application of evidence-based guidelines to support sustained changes in practice, and ultimately improve patient care. PMID:27307722

Characterization of the Effects of Hyperbaric Oxygen on the Biochemical and Optical Properties of the Bovine Lens.

PubMed

Lim, Julie C; Vaghefi, Ehsan; Li, Bo; Nye-Wood, Mitchell G; Donaldson, Paul J

2016-04-01

To assess the morphologic, biochemical, and optical properties of bovine lenses treated with hyperbaric oxygen. Lenses were exposed to hyperbaric nitrogen (HBN) or hyperbaric oxygen (HBO) for 5 or 15 hours, lens transparency was assessed using bright field microscopy and lens morphology was visualized using confocal microscopy. Lenses were dissected into the outer cortex, inner cortex, and core, and glutathione (GSH) and malondialdehyde (MDA) measured. Gel electrophoresis and Western blotting were used to detect high molecular weight aggregates (HMW) and glutathione mixed protein disulfides (PSSG). T2-weighted MRI was used to measure lens geometry and map the water/protein ratio to allow gradient refractive index (GRIN) profiles to be calculated. Optical modeling software calculated the change in lens optical power, and an anatomically correct model of the light pathway of the bovine eye was used to determine the effects of HBN and HBO on focal length and overall image quality. Lenses were transparent and lens morphology similar between HBN- and HBO-treated lenses. At 5- and 15-hour HBO exposure, GSH and GSSG were depleted and MDA increased in the core. Glutathione mixed protein disulfides were detected in the outer and inner cortex only with no appearance of HMW. Optical changes were detectable only with 15-hour HBO treatment with a decrease in the refractive index of the core, slightly reduced lens thickness, and an increase in optimal focal length, consistent with a hyperopic shift. This system may serve as a model to study changes that occur with advanced aging rather than nuclear cataract formation per se.

Algal Biomass as an Indicator for Biochemical Oxygen Demand in the San Joaquin River, California.

NASA Astrophysics Data System (ADS)

Volkmar, E. C.; Dalhgren, R. A.

2005-12-01

Episodes of hypoxia (DO < 2 mg/L) occur in the lower San Joaquin River (SJR), California, and are typically most acute in the late summer and fall. The oxygen deficit can stress and kill aquatic organisms, and often inhibits the upstream migration of fall-run Chinook salmon. Hypoxia is most pronounced downstream from the Stockton Deep Water Ship Channel, which has been dredged from a depth of 2-3 m to about 11 m to allow ocean-going ships to reach the Port of Stockton. To protect aquatic organisms and facilitate the upstream migration of fall-run Chinook salmon, the minimum water quality standard for DO is 6 mg/L during September through November, and 5 mg/L for the remainder of the year. A five year study examined components contributing to biochemical oxygen demand (BOD): ammonia, algal biomass, non-algal particulate organic matter, and dissolved organic carbon. BOD shows a significant increase in loading rates as the SJR flows downstream, which parallels the load of algal biomass due to instream growth. BOD loading rates from tributaries accounts for 28% in a wet year and 39% in a dry year. Regression analysis revealed that chlorophyll-a + pheophyton-a was the only significant (p<0.05) predictor for BOD (r2 = 0.71). Less than 20% of the BOD was found in the dissolved fraction (<0.45 μm). The average BOD decomposition rate of the SJR and tributaries is 0.0841 d-1. We conclude that algal biomass is the primary contributor to BOD loads in the San Joaquin River.

Three-dimensional three-phase model for simulation of hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification in an oxidation ditch.

PubMed

Lei, Li; Ni, Jinren

2014-04-15

A three-dimensional three-phase fluid model, supplemented by laboratory data, was developed to simulate the hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification processes in an oxidation ditch. The model provided detailed phase information on the liquid flow field, gas hold-up distribution and sludge sedimentation. The three-phase model described water-gas, water-sludge and gas-sludge interactions. Activated sludge was taken to be in a pseudo-solid phase, comprising an initially separated solid phase that was transported and later underwent biological reactions with the surrounding liquidmedia. Floc parameters were modified to improve the sludge viscosity, sludge density, oxygen mass transfer rate, and carbon substrate uptake due to adsorption onto the activated sludge. The validation test results were in very satisfactory agreement with laboratory data on the behavior of activated sludge in an oxidation ditch. By coupling species transport and biological process models, reasonable predictions are made of: (1) the biochemical kinetics of dissolved oxygen, chemical oxygen demand (COD) and nitrogen variation, and (2) the physical kinematics of sludge sedimentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

The response of the tidepool sculpin, Oligocottus maculosus, to hypoxia in laboratory, mesocosm and field environments.

PubMed

Sloman, Katherine A; Mandic, Milica; Todgham, Anne E; Fangue, Nann A; Subrt, Peter; Richards, Jeffrey G

2008-03-01

Animals living in the intertidal zone experience regular, predictable fluctuations in physical parameters including temperature, oxygen and salinity and rely on behavioural, physiological and biochemical mechanisms to cope with environmental variation. In the present study, behavioural strategies induced by aquatic hypoxia (e.g. emergence) were performed at similar oxygen tensions across laboratory, mesocosm and field environments; the number of individuals performing these behaviours at any one time was similar in mesocosms and the field. The use of aquatic surface respiration (ASR) was more plastic than emergence behaviour, occurring at a lower oxygen tension in juveniles than adults and being influenced by the addition of alarm substance. Oxygen uptake was lower in air than in water in adults but, in contrast, oxygen uptake was not influenced by the respiratory medium in juveniles. In the laboratory, 72 h of forced emergence did not affect whole body concentrations of lactate but when ASR and emergence were prevented within mesocosm environments there was a significant elevation of lactate. The present study highlights the benefits of transcending traditional laboratory/field boundaries allowing the responses of laboratory-held animals to environmental fluctuation to be integrated with how these animals perform in their natural environment.

Effect of sleep-wake reversal and sleep deprivation on the circadian rhythm of oxygen toxicity seizure susceptibility.

NASA Technical Reports Server (NTRS)

Dexter, J. D.; Hof, D. G.; Mengel, C. E.

1972-01-01

Albino Sprague-Dawley rats were exposed in a previously O2 flushed, CO2 free chamber. The exposure began with attainment of 60 psi (gauge) and the end point was the first generalized oxygen toxicity seizure. Animals were exposed to reversal diurnal conditions since weanlings until their sleep-wake cycles had completely reversed, and then divided into four groups of 20 based on the time of day exposed. The time of exposure to oxygen at high pressure prior to seizure was now significantly longer in the group exposed from 1900 to 2000 hr and a reversal of the circadian rhythm of oxygen toxicity seizure susceptibility was noted. Animals maintained on normal diurnal conditions were deprived of sleep on the day of exposure for the 12 hours prior to exposure at 1900 hr, while controls were allowed to sleep. There was no significant differences in the time prior to seizure between the deprived animals and the controls with an n = 40. Thus the inherent threshold in susceptibility to high-pressure oxygen seizures seems not to be a function of sleep itself, but of some biochemical/physiologic event which manifests a circadian rhythm.

In Vivo Mitochondrial Oxygen Tension Measured by a Delayed Fluorescence Lifetime Technique

PubMed Central

Mik, Egbert G.; Johannes, Tanja; Zuurbier, Coert J.; Heinen, Andre; Houben-Weerts, Judith H. P. M.; Balestra, Gianmarco M.; Stap, Jan; Beek, Johan F.; Ince, Can

2008-01-01

Mitochondrial oxygen tension (mitoPO2) is a key parameter for cellular function, which is considered to be affected under various pathophysiological circumstances. Although many techniques for assessing in vivo oxygenation are available, no technique for measuring mitoPO2 in vivo exists. Here we report in vivo measurement of mitoPO2 and the recovery of mitoPO2 histograms in rat liver by a novel optical technique under normal and pathological circumstances. The technique is based on oxygen-dependent quenching of the delayed fluorescence lifetime of protoporphyrin IX. Application of 5-aminolevulinic acid enhanced mitochondrial protoporphyrin IX levels and induced oxygen-dependent delayed fluorescence in various tissues, without affecting mitochondrial respiration. Using fluorescence microscopy, we demonstrate in isolated hepatocytes that the signal is of mitochondrial origin. The delayed fluorescence lifetime was calibrated in isolated hepatocytes and isolated perfused livers. Ultimately, the technique was applied to measure mitoPO2 in rat liver in vivo. The results demonstrate mitoPO2 values of ∼30–40 mmHg. mitoPO2 was highly sensitive to small changes in inspired oxygen concentration around atmospheric oxygen level. Ischemia-reperfusion interventions showed altered mitoPO2 distribution, which flattened overall compared to baseline conditions. The reported technology is scalable from microscopic to macroscopic applications, and its reliance on an endogenous compound greatly enhances its potential field of applications. PMID:18641065

Oxygen Release Induced Chemomechanical Breakdown of Layered Cathode Materials

DOE PAGES

Mu, Linqin; Lin, Ruoqian; Xu, Rong; ...

2018-04-18

Chemical and mechanical properties interplay on the nanometric scale and collectively govern the functionalities of battery materials. Understanding the relationship between the two can inform the design of battery materials with optimal chemomechanical properties for long-life lithium batteries. Herein, we report a mechanism of nanoscale mechanical breakdown in layered oxide cathode materials, originating from oxygen release at high states of charge under thermal abuse conditions. Here, we observe that the mechanical breakdown of charged Li 1-xNi 0.4Mn 0.4Co 0.2O 2 materials proceeds via a two-step pathway involving intergranular and intragranular crack formation. Owing to the oxygen release, sporadic phase transformationsmore » from the layered structure to the spinel and/or rocksalt structures introduce local stress, which initiates microcracks along grain boundaries and ultimately leads to the detachment of primary particles; i.e., intergranular crack formation. Furthermore, intragranular cracks (pores and exfoliations) form, likely due to the accumulation of oxygen vacancies and continuous phase transformations at the surfaces of primary particles. Finally, finite element modeling confirms our experimental observation that the crack formation is attributable to formation of oxygen vacancies, oxygen release, and phase transformations. This study is designed to directly observe the chemomechanical behavior of layered oxide cathode materials and provides a chemical basis for strengthening primary and secondary particles by stabilizing the oxygen anions in the lattice.« less

Oxygen Release Induced Chemomechanical Breakdown of Layered Cathode Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Linqin; Lin, Ruoqian; Xu, Rong

Chemical and mechanical properties interplay on the nanometric scale and collectively govern the functionalities of battery materials. Understanding the relationship between the two can inform the design of battery materials with optimal chemomechanical properties for long-life lithium batteries. Herein, we report a mechanism of nanoscale mechanical breakdown in layered oxide cathode materials, originating from oxygen release at high states of charge under thermal abuse conditions. Here, we observe that the mechanical breakdown of charged Li 1-xNi 0.4Mn 0.4Co 0.2O 2 materials proceeds via a two-step pathway involving intergranular and intragranular crack formation. Owing to the oxygen release, sporadic phase transformationsmore » from the layered structure to the spinel and/or rocksalt structures introduce local stress, which initiates microcracks along grain boundaries and ultimately leads to the detachment of primary particles; i.e., intergranular crack formation. Furthermore, intragranular cracks (pores and exfoliations) form, likely due to the accumulation of oxygen vacancies and continuous phase transformations at the surfaces of primary particles. Finally, finite element modeling confirms our experimental observation that the crack formation is attributable to formation of oxygen vacancies, oxygen release, and phase transformations. This study is designed to directly observe the chemomechanical behavior of layered oxide cathode materials and provides a chemical basis for strengthening primary and secondary particles by stabilizing the oxygen anions in the lattice.« less

Optically based quantification of absolute cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution in rodents

NASA Astrophysics Data System (ADS)

Yaseen, Mohammad A.; Srinivasan, Vivek J.; Sakadžić, Sava; Vinogradov, Sergei A.; Boas, David A.

2010-02-01

Measuring oxygen delivery in brain tissue is important for identifying the pathophysiological changes associated with brain injury and various diseases such as cancer, stroke, and Alzheimer's disease. We have developed a multi-modal imaging system for minimally invasive measurement of cerebral oxygenation and blood flow in small animals with high spatial resolution. The system allows for simultaneous measurement of blood flow using Fourier-domain optical coherence tomography, and oxygen partial pressure (pO2) using either confocal or multiphoton phosphorescence lifetime imaging with exogenous porphyrin-based dyes sensitive to dissolved oxygen. Here we present the changes in pO2 and blood flow in superficial cortical vessels of Sprague Dawley rats in response to conditions such as hypoxia, hyperoxia, and functional stimulation. pO2 measurements display considerable heterogeneity over distances that cannot be resolved with more widely used oxygen-monitoring techniques such as BOLD-fMRI. Large increases in blood flow are observed in response to functional stimulation and hypoxia. Our system allows for quantification of cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution, providing a better understanding of metabolic dynamics during functional stimulation and under various neuropathologies. Ultimately, better insight into the underlying mechanisms of neuropathologies will facilitate the development of improved therapeutic strategies to minimize damage to brain tissue.

Metabolomic Analyses of Plasma Reveals New Insights into Asphyxia and Resuscitation in Pigs

PubMed Central

Solberg, Rønnaug; Enot, David; Deigner, Hans-Peter; Koal, Therese; Scholl-Bürgi, Sabine; Saugstad, Ola D.; Keller, Matthias

2010-01-01

Background Currently, a limited range of biochemical tests for hypoxia are in clinical use. Early diagnostic and functional biomarkers that mirror cellular metabolism and recovery during resuscitation are lacking. We hypothesized that the quantification of metabolites after hypoxia and resuscitation would enable the detection of markers of hypoxia as well as markers enabling the monitoring and evaluation of resuscitation strategies. Methods and Findings Hypoxemia of different durations was induced in newborn piglets before randomization for resuscitation with 21% or 100% oxygen for 15 min or prolonged hyperoxia. Metabolites were measured in plasma taken before and after hypoxia as well as after resuscitation. Lactate, pH and base deficit did not correlate with the duration of hypoxia. In contrast to these, we detected the ratios of alanine to branched chained amino acids (Ala/BCAA; R2.adj = 0.58, q-value<0.001) and of glycine to BCAA (Gly/BCAA; R2.adj = 0.45, q-value<0.005), which were highly correlated with the duration of hypoxia. Combinations of metabolites and ratios increased the correlation to R2adjust = 0.92. Reoxygenation with 100% oxygen delayed cellular metabolic recovery. Reoxygenation with different concentrations of oxygen reduced lactate levels to a similar extent. In contrast, metabolites of the Krebs cycle (which is directly linked to mitochondrial function) including alpha keto-glutarate, succinate and fumarate were significantly reduced at different rates depending on the resuscitation, showing a delay in recovery in the 100% reoxygenation groups. Additional metabolites showing different responses to reoxygenation include oxysterols and acylcarnitines (n = 8–11, q<0.001). Conclusions This study provides a novel strategy and set of biomarkers. It provides biochemical in vivo data that resuscitation with 100% oxygen delays cellular recovery. In addition, the oxysterol increase raises concerns about the safety of 100% O2 resuscitation. Our biomarkers can be used in a broad clinical setting for evaluation or the prediction of damage in conditions associated with low tissue oxygenation in both infancy and adulthood. These findings have to be validated in human trials. PMID:20231903

Metabolomic analyses of plasma reveals new insights into asphyxia and resuscitation in pigs.

PubMed

Solberg, Rønnaug; Enot, David; Deigner, Hans-Peter; Koal, Therese; Scholl-Bürgi, Sabine; Saugstad, Ola D; Keller, Matthias

2010-03-09

Currently, a limited range of biochemical tests for hypoxia are in clinical use. Early diagnostic and functional biomarkers that mirror cellular metabolism and recovery during resuscitation are lacking. We hypothesized that the quantification of metabolites after hypoxia and resuscitation would enable the detection of markers of hypoxia as well as markers enabling the monitoring and evaluation of resuscitation strategies. Hypoxemia of different durations was induced in newborn piglets before randomization for resuscitation with 21% or 100% oxygen for 15 min or prolonged hyperoxia. Metabolites were measured in plasma taken before and after hypoxia as well as after resuscitation. Lactate, pH and base deficit did not correlate with the duration of hypoxia. In contrast to these, we detected the ratios of alanine to branched chained amino acids (Ala/BCAA; R(2).adj = 0.58, q-value<0.001) and of glycine to BCAA (Gly/BCAA; R(2).adj = 0.45, q-value<0.005), which were highly correlated with the duration of hypoxia. Combinations of metabolites and ratios increased the correlation to R(2)adjust = 0.92. Reoxygenation with 100% oxygen delayed cellular metabolic recovery. Reoxygenation with different concentrations of oxygen reduced lactate levels to a similar extent. In contrast, metabolites of the Krebs cycle (which is directly linked to mitochondrial function) including alpha keto-glutarate, succinate and fumarate were significantly reduced at different rates depending on the resuscitation, showing a delay in recovery in the 100% reoxygenation groups. Additional metabolites showing different responses to reoxygenation include oxysterols and acylcarnitines (n = 8-11, q<0.001). This study provides a novel strategy and set of biomarkers. It provides biochemical in vivo data that resuscitation with 100% oxygen delays cellular recovery. In addition, the oxysterol increase raises concerns about the safety of 100% O(2) resuscitation. Our biomarkers can be used in a broad clinical setting for evaluation or the prediction of damage in conditions associated with low tissue oxygenation in both infancy and adulthood. These findings have to be validated in human trials.

Cancer: Mitochondrial Origins.

PubMed

Stefano, George B; Kream, Richard M

2015-12-01

The primacy of glucose derived from photosynthesis as an existential source of chemical energy across plant and animal phyla is universally accepted as a core principle in the biological sciences. In mammalian cells, initial processing of glucose to triose phosphate intermediates takes place within the cytosolic glycolytic pathway and terminates with temporal transport of reducing equivalents derived from pyruvate metabolism by membrane-associated respiratory complexes in the mitochondrial matrix. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionary fashioned chemiosmotic production of ATP as a high-efficiency biological process. The mechanistic bases of carcinogenesis have demonstrated profound alteration of normative mitochondrial function, notably dysregulated respiratory processes. Accordingly, the classic Warburg effect functionally links aerobic glycolysis, aberrant production and release of lactate, and metabolic down-regulation of mitochondrial oxidative processes with the carcinogenetic phenotype. We surmise, however, that aerobic fermentation by cancer cells may also represent a developmental re-emergence of an evolutionarily conserved early phenotype, which was "sidelined" with the emergence of mitochondrial oxidative phosphorylation as a primary mechanism for ATP production in normal cells. Regardless of state-dependent physiological status in mixed populations of cancer cells, it has been established that mitochondria are functionally linked to the initiation of cancer and its progression. Biochemical, molecular, and physiological differences in cancer cell mitochondria, notably mtDNA heteroplasmy and allele-specific expression of selected nuclear genes, may represent major focal points for novel targeting and elimination of cancer cells in metastatic disease afflicting human populations. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial targeted therapies has not been forthcoming.

Characterisation of the initial degradation stage of Scots pine (Pinus sylvestris L.) sapwood after attack by brown-rot fungus Coniophora puteana.

PubMed

Irbe, Ilze; Andersone, Ingeborga; Andersons, Bruno; Noldt, Guna; Dizhbite, Tatiana; Kurnosova, Nina; Nuopponen, Mari; Stewart, Derek

2011-07-01

In our study, early period degradation (10 days) of Scots pine (Pinus sylvestris L.) sapwood by the brown-rot fungus Coniophora puteana (Schum.: Fr.) Karst. (BAM Ebw.15) was followed at the wood chemical composition and ultrastructure-level, and highlighted the generation of reactive oxygen species (ROS). An advanced decay period of 50 days was chosen for comparison of the degradation dynamics. Scanning UV microspectrophotometry (UMSP) analyses of lignin distribution in wood cells revealed that the linkages of lignin and polysaccharides were already disrupted in the early period of fungal attack. An increase in the lignin absorption A(280) value from 0.24 (control) to 0.44 in decayed wood was attributed to its oxidative modification which has been proposed to be generated by Fenton reaction derived ROS. The wood weight loss in the initial degradation period was 2%, whilst cellulose and lignin content decreased by 6.7% and 1%, respectively. Lignin methoxyl (-OCH3) content decreased from 15.1% (control) to 14.2% in decayed wood. Diffuse reflectance Fourier-transform infrared (DRIFT) spectroscopy corroborated the moderate loss in the hemicellulose and lignin degradation accompanying degradation. Electron paramagnetic resonance spectra and spin trapping confirmed the generation of ROS, such as hydroxyl radicals (HO∙), in the early wood degradation period. Our results showed that irreversible changes in wood structure started immediately after wood colonisation by fungal hyphae and the results generated here will assist in the understanding of the biochemical mechanisms of wood biodegradation by brown-rot fungi with the ultimate aim of developing novel wood protection methods.

Role of CFTR in oxidative stress and suicidal death of renal cells during cisplatin-induced nephrotoxicity

PubMed Central

Rubera, I; Duranton, C; Melis, N; Cougnon, M; Mograbi, B; Tauc, M

2013-01-01

The clinical use of the antineoplastic drug cisplatin is limited by its deleterious nephrotoxic side effect. Cisplatin-induced nephrotoxicity is associated with an increase in oxidative stress, leading ultimately to renal cell death and irreversible kidney dysfunction. Oxidative stress could be modified by the cystic fibrosis transmembrane conductance regulator protein (CFTR), a Cl− channel not only involved in chloride secretion but as well in glutathione (GSH) transport. Thus, we tested whether the inhibition of CFTR could protect against cisplatin-induced nephrotoxicity. Using a renal proximal cell line, we show that the specific inhibitor of CFTR, CFTRinh-172, prevents cisplatin-induced cell death and apoptosis by modulating the intracellular reactive oxygen species balance and the intracellular GSH concentration. This CFTRinh-172-mediated protective effect occurs without affecting cellular cisplatin uptake or the formation of platinum-DNA adducts. The protective effect of CFTRinh-172 in cisplatin-induced nephrotoxicity was also investigated in a rat model. Five days after receiving a single cisplatin injection (5 mg/kg), rats exhibited renal failure, as evidenced by the alteration of biochemical and functional parameters. Pretreatment of rats with CFTRinh-172 (1 mg/kg) prior to cisplatin injection significantly prevented these deleterious cisplatin-induced nephrotoxic effects. Finally, we demonstrate that CFTRinh-172 does not impair cisplatin-induced cell death in the cisplatin-sensitive A549 cancer cell line. In conclusion, the use of a specific inhibitor of CFTR may represent a novel therapeutic approach in the prevention of nephrotoxic side effects during cisplatin treatment without affecting its antitumor efficacy. PMID:24091660

Responses of Noccaea caerulescens and Lupinus albus in trace elements-contaminated soils.

PubMed

Martínez-Alcalá, Isabel; Hernández, Luis E; Esteban, Elvira; Walker, David J; Bernal, M Pilar

2013-05-01

Plants exposed to trace elements can suffer from oxidative stress, which is characterised by the accumulation of reactive oxygen species, alteration in the cellular antioxidant defence system and ultimately lipid peroxidation. We assessed the most-appropriate stress indexes to describe the response of two plant species, with different strategies for coping with trace elements (TEs), to particular contaminants. Noccaea caerulescens, a hyperaccumulator, and Lupinus albus, an excluder, were grown in three soils of differing pH: an acidic soil, a neutral soil (both contaminated mainly by Cu, Zn and As) and a control soil. Then, plant stress indicators were measured. As expected, N. caerulescens accumulated higher levels of Zn and Cd in shoots than L. albus, this effect being stronger in the acid soil, reflecting greater TE solubility in this soil. However, the shoot concentrations of Mn were higher in L. albus than in N. caerulescens, while the As concentration was similar in the two species. In L. albus, the phenolic content and lipid peroxidation were related with the Cu concentration, whereas the Zn and Cd concentrations in N. caerulescens were more closely related to glutathione content and lipid peroxidation. Interestingly, phytochelatins were only found in L. albus grown in polluted soils. Hence, the two species differed with respect to the TEs which provoked stress and the biochemical indicators of the stress, there being a close relationship between the accumulation of TEs and their associated stress indicators in the different plant organs. Crown Copyright © 2013. Published by Elsevier Masson SAS. All rights reserved.

Drugs of abuse and addiction: A slippery slope toward liver injury.

PubMed

Roy, Dijendra Nath; Goswami, Ritobrata

2016-08-05

Substances of abuse induce alteration in neurobehavioral symptoms, which can lead to simultaneous exacerbation of liver injury. The biochemical changes of liver are significantly observed in the abused group of people using illicit drugs or drugs that are abused. A huge amount of work has been carried out by scientists for validation experiments using animal models to assess hepatotoxicity in cases of drugs of abuse. The risk of hepatotoxicity from these psychostimulants has been determined by different research groups. Hepatotoxicity of these drugs has been recently highlighted and isolated case reports always have been documented in relation to misuse of the drugs. These drugs induce liver toxicity on acute or chronic dose dependent process, which ultimately lead to liver damage, acute fatty infiltration, cholestatic jaundice, liver granulomas, hepatitis, liver cirrhosis etc. Considering the importance of drug-induced hepatotoxicity as a major cause of liver damage, this review emphasizes on various drugs of abuse and addiction which induce hepatotoxicity along with their mechanism of liver damage in clinical aspect as well as in vitro and in vivo approach. However, the mechanisms of drug-induced hepatotoxicity is dependent on reactive metabolite formation via metabolism, modification of covalent bonding between cellular components with drug and its metabolites, reactive oxygen species generation inside and outside of hepatocytes, activation of signal transduction pathways that alter cell death or survival mechanism, and cellular mitochondrial damage, which leads to alteration in ATP generation have been notified here. Moreover, how the cytokines are modulated by these drugs has been mentioned here. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Appraisal of storm-water quality near Salem, Oregon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, T.L.

Stormwater runoff for the period December 1979 to May 1981, at 13 sites in the vicinity of Salem, Oregon, was sampled and analyzed for water quality. Constituent concentrations for urban storm water were relatively small when compared to samples from Portland and Medford, Oregon and to samples from Denver, Colorado. The data indicated that levels of suspended sediment, ultimate CBOD (carbonaceous biochemical oxygen demand), and total lead increased with increased urbanization. Because of small chemical concentrations and winter high flow and low temperature conditions in the Willamette River, Salem storm water probably has little effect on biological or on mostmore » chemical conditions in the Willamette River. An analysis of data from a stormwater detention pond indicated that the facility was about 47% efficient in reducing suspended sediment loads. Precipitation samples collected at one site for a year were found to be acidic, with a median pH of 4.6. Median total lead concentration was 8 micrograms/L (ug/L) in precipitation, whereas the median total lead concentration in runoff from the 12 basins ranged from 8 to 110 ug/L. The median dissolved ammonia concentration in precipitation was larger than the median dissolved ammonia concentration at all 13 sites. In contrast, the median total Kjeldahl nitrogen concentration in precipitation samples was about half the median for streamwater concentrations. Median ratios of sulfate to chloride and nitrate to chloride in precipitation were much higher than ratios expected for sea water, suggesting anthropogenic sources for sulfate and nitrate. 24 refs., 6 figs., 7 tabs.« less

Responses to flooding of plant water relations and leaf gas exchange in tropical tolerant trees of a black-water wetland.

PubMed

Herrera, A

2013-01-01

This review summarizes the research on physiological responses to flooding of trees in the seasonal black-water wetland of the Mapire River in Venezuela. Inter-annual variability was found during 8 years of sampling, in spite of which a general picture emerged of increased stomatal conductance (gs) and photosynthetic rate (PN) during the flooded period to values as high as or higher than in plants in drained wet soil. Models explaining the initial inhibitory responses and the acclimation to flooding are proposed. In the inhibitory phase of flooding, hypoxia generated by flooding causes a decrease in root water absorption and stomatal closure. An increase with flooding in xylem water potential (ψ) suggests that flooding does not cause water deficit. The PN decreases due to changes in relative stomatal and non-stomatal limitations to photosynthesis; an increase in the latter is due to reduced chlorophyll and total soluble protein content. Total non-structural carbohydrates (TNC) accumulate in leaves but their content begins to decrease during the acclimatized phase at full flooding, coinciding with the resumption of high gs and PN. The reversal of the diminution in gs is associated, in some but not all species, to the growth of adventitious roots. The occurrence of morpho-anatomical and biochemical adaptations which improve oxygen supply would cause the acclimation, including increased water absorption by the roots, increased rubisco and chlorophyll contents and ultimately increased PN. Therefore, trees would perform as if flooding did not signify a stress to their physiology.

Rhabdomyolysis in a recreational swimmer.

PubMed

Stella, J J; Shariff, A H

2012-02-01

Rhabdomyolysis is a clinical and biochemical syndrome resulting from skeletal muscle injury, which may ultimately lead to acute renal failure (ARF) and death. Exertional rhabdomyolysis refers to skeletal muscle injury that is usually induced by strenuous eccentric exercises in a hot and humid environment. It is usually seen in marathoners and military personnel. We present the case of a 32-year-old Malaysian man who had rhabdomyolysis and myoglobinuria without ARF after two episodes of unaccustomed swimming. He was treated conservatively, and recovered uneventfully. A brief discussion on the pathophysiology of rhabdomyolysis, the principles of management and recuperation is included.

Resolving the intermediate and deep advective flows in the Indian Ocean by using temperature, salinity, oxygen and phosphate data: the interplay of biogeochemical and geophysical tracers

NASA Astrophysics Data System (ADS)

Metzl, N.; Moore, B.; Poisson, A.

1990-10-01

For computing large-scale advective flow in the Indian ocean (including the Indian-Antarctic sector), we use a box-model approach and perturbed inverse method. The top 400 meters is not considered in this study, in view of the dominant seasonal dynamics. We use 1244 hydrographic stations, to estimate mean values for temperature, salinity, oxygen and phosphate concentratons. Fifty perturbed inversions of steady-state tracers conservations and thermal-wind equations are done using box-averages standard deviations and a 25% perturbation on the thermal-wind coefficients. The mean solutions represent the large-scale advective flow and carbon-decomposition rates in which we are interested. Solutions with only advective processes are first considered. The broad features of the circulation in the Indian Ocean are resolved in the intermediate levels, but in deeper layers, an input from North Atlantic Deep Water (NADW) is not apparent. Inspection of oxygen and phosphate residuals reveals a biochemical signal. Therefore, we introduce in the oxygen and phosphate budgets a linear parameterization (Redfield ratios) for the organic-decomposition processes. The structure of the residuals for oxygen and phosphate is changed in that the biochemical signal vanishes. The advective solutions are nearly the same in intermediate waters; however, in deep layers the new solution shows an inflow of 11 (±8) Sv of NADW south of Africa. The calculated total organic decomposition of 0.93 (±0.25) 10 15g C year -1 is about one fifth of the estimated world ocean amount, but total residuals of oxygen and phosphate lead to an unexplained 0.5 10 15g C year -1 missing carbon sink. The new solution does contain unrealistic elements (e.g. large deep flow between Indonesia and Australia). Finally, to investigate this last result, we add one advective constraint at the Indonesia-Australia boundary. This addition changes the circulation in the northeastern part of the Indian Ocean. The circumpolar flow between 400 m and 27.65 (σo) remains unchanged at 20°E and at 80°E; however, at 130°E the constraint increases the advective flow by 20%. Total organic-carbon-decomposition rates are not affected by the additional inflow from Indonesia.

Biochemical response of hybrid black poplar tissue culture (Populus × canadensis) on water stress.

PubMed

Popović, B M; Štajner, D; Ždero-Pavlović, R; Tari, I; Csiszár, J; Gallé, Á; Poór, P; Galović, V; Trudić, B; Orlović, S

2017-05-01

In this study, poplar tissue culture (hybrid black poplar, M1 genotype) was subjected to water stress influenced by polyethyleneglycol 6000 (100 and 200 mOsm PEG 6000). The aim of the research was to investigate the biochemical response of poplar tissue culture on water deficit regime. Antioxidant status was analyzed including antioxidant enzymes, superoxide-dismutase (SOD), catalase (CAT), guiacol-peroxidase (GPx), glutathione-peroxidase (GSH-Px), glutathione-reductase, reduced glutathione, total phenol content, Ferric reducing antioxidant power and DPPH radical antioxidant power. Polyphenol oxidase and phenylalanine-ammonium-lyase were determined as enzymatic markers of polyphenol metabolism. Among oxidative stress parameters lipid peroxidation, carbonyl-proteins, hydrogen-peroxide, reactive oxygen species, nitric-oxide and peroxynitrite were determined. Proline, proline-dehydrogenase and glycinebetaine were measured also as parameters of water stress. Cell viability is finally determined as a biological indicator of osmotic stress. It was found that water stress induced reactive oxygen and nitrogen species and lipid peroxidation in leaves of hybrid black poplar and reduced cell viability. Antioxidant enzymes including SOD, GPx, CAT and GSH-Px were induced but total phenol content and antioxidant capacity were reduced by PEG 6000 mediated osmotic stress. The highest biochemical response and adaptive reaction was the increase of proline and GB especially by 200 mOsm PEG. While long term molecular analysis will be necessary to fully address the poplar potentials for water stress adaptation, our results on hybrid black poplar suggest that glycine-betaine, proline and PDH enzyme might be the most important markers of poplar on water stress and that future efforts should be focused on these markers and strategies to enhance their concentration in poplar.

Effect of azoxystrobin fungicide on the physiological and biochemical indices and ginsenoside contents of ginseng leaves.

PubMed

Liang, Shuang; Xu, Xuanwei; Lu, Zhongbin

2018-04-01

The impact of fungicide azoxystrobin, applied as foliar spray, on the physiological and biochemical indices and ginsenoside contents of ginseng was studied in ginseng ( Panax ginseng Mey. cv. "Ermaya") under natural environmental conditions. Different concentrations of 25% azoxystrobin SC (150 g a.i./ha and 225 g a.i./ha) on ginseng plants were sprayed three times, and the changes in physiological and biochemical indices and ginsenoside contents of ginseng leaves were tested. Physiological and biochemical indices were measured using a spectrophotometer (Shimadzu UV-2450). Every index was determined three times per replication. Extracts of ginsenosides were analyzed by HPLC (Shimadzu LC20-AB) utilizing a GL-Wondasil C 18 column. Chlorophyll and soluble protein contents were significantly ( p  = 0.05) increased compared with the control by the application of azoxystrobin. Additionally, activities of superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, and ginsenoside contents in azoxystrobin-treated plants were improved, and malondialdehyde content and O 2 - contents were reduced effectively. Azoxystrobin treatments to ginseng plants at all growth stages suggested that the azoxystrobin-induced delay of senescence was due to an enhanced antioxidant enzyme activity protecting the plants from harmful active oxygen species. When the dose of azoxystrobin was 225 g a.i./ha, the effect was more significant. This work suggested that azoxystrobin played a role in delaying senescence by changing physiological and biochemical indices and improving ginsenoside contents in ginseng leaves.

Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve.

PubMed

Collins, Julie-Ann; Rudenski, Aram; Gibson, John; Howard, Luke; O'Driscoll, Ronan

2015-09-01

The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content), saturation (S O2 ) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin-oxygen dissociation curve, a graphical representation of the relationship between oxygen satur-ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the S O2 in blood from patients with normal pH and S O2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (S pO2 ) is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (S aO2 ) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S pO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

Mechanical properties of Ti-6Al-4V specimens produced by shaped metal deposition

PubMed Central

Baufeld, Bernd; van der Biest, Omer

2009-01-01

Shaped metal deposition is a novel technique to build near net-shape components layer by layer by tungsten inert gas welding. Especially for complex shapes and small quantities, this technique can significantly lower the production cost of components by reducing the buy-to-fly ratio and lead time for production, diminishing final machining and preventing scrap. Tensile testing of Ti-6Al-4V components fabricated by shaped metal deposition shows that the mechanical properties are competitive to material fabricated by conventional techniques. The ultimate tensile strength is between 936 and 1014 MPa, depending on the orientation and location. Tensile testing vertical to the deposition layers reveals ductility between 14 and 21%, whereas testing parallel to the layers gives a ductility between 6 and 11%. Ultimate tensile strength and ductility are inversely related. Heat treatment within the α+β phase field does not change the mechanical properties, but heat treatment within the β phase field increases the ultimate tensile strength and decreases the ductility. The differences in ultimate tensile strength and ductility can be related to the α lath size and orientation of the elongated, prior β grains. The micro-hardness and Young’s modulus are similar to conventional Ti-6Al-4V with low oxygen content. PMID:27877271

Effects of Mitochondrial Antioxidant SkQ1 on Biochemical and Behavioral Parameters in a Parkinsonism Model in Mice.

PubMed

Pavshintsev, V V; Podshivalova, L S; Frolova, O Y; Belopolskaya, M V; Averina, O A; Kushnir, E A; Marmiy, N V; Lovat, M L

2017-12-01

According to one hypothesis, Parkinson's disease pathogenesis is largely caused by dopamine catabolism that is catalyzed on mitochondrial membranes by monoamine oxidase. Reactive oxygen species are formed as a byproduct of these reactions, which can lead to mitochondrial damage followed by cell degeneration and death. In this study, we investigated the effects of administration of the mitochondrial antioxidant SkQ1 on biochemical, immunohistochemical, and behavioral parameters in a Parkinson-like condition caused by protoxin MPTP injections in C57BL/6 mice. SkQ1 administration increased dopamine quantity and decreased signs of sensory-motor deficiency as well as destruction of dopaminergic neurons in the substantia nigra and ventral tegmental area in mice with the Parkinson-like condition.

Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry

NASA Astrophysics Data System (ADS)

Hickey, M.; Kyriacou, P. A.

2007-10-01

Splanchnic ischaemia can ultimately lead to cellular hypoxia and necrosis, and may well contribute to the development of multiple organ failures and increased mortality. Therefore, it is of utmost importance to monitor abdominal organ blood oxygen saturation (SpO2). Pulse oximetry has been widely accepted as a reliable method for monitoring oxygen saturation of arterial blood. Animal studies have also shown it to be effective in the monitoring of blood oxygen saturation in the splanchnic region. However, commercially available pulse oximeter probes are not suitable for the continuous assessment of SpO2 in the splanchnic region. Therefore, there is a need for a new sensor technology that will allow the continuous measurement of SpO2 in the splanchnic area pre-operatively, operatively and post-operatively. For this purpose, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. The accuracy in the estimation of SpO2 in pulse oximetry depends on the quality and amplitude of the photoplethysmographic (PPG) signal and for this reason an experimental procedure was carried out to examine the effect of the source-detector separation distance on the acquired PPG signals, and to ultimately select an optimal separation for the final design of the fibre-optic probe. PPG signals were obtained from the finger for different separation distances between the emitting and detecting fibres. Good quality PPG signals with large amplitudes and high signal-to-noise ratio were detected in the range of 3mm to 6mm. At separation distances between 1mm and 2mm, PPG signals were erratic with no resemblance to a conventional PPG signal. At separation distances greater than 6mm, the amplitudes of PPG signals were very small and not appropriate for processing. This investigation indicates the suitability of optical fibres as a new pulse oximetry sensor for estimating blood oxygen saturation (SpO2) in the splanchnic region.

Effects of hypoxia and reoxygenation on the expression levels of the urokinase-type plasminogen activator, its inhibitor plasminogen activator inhibitor type-1 and the urokinase-type plasminogen activator receptor in human head and neck tumour cells.

PubMed

Sprague, Lisa D; Tomaso, Herbert; Mengele, Karin; Schilling, Daniela; Bayer, Christine; Stadler, Peter; Schmitt, Manfred; Molls, Michael

2007-05-01

One aim during oncological radiation therapy is to induce reoxygenation in hypoxic tumours in order to enhance radiosensitivity and ultimately increase cell death. In squamous cell carcinomas of the head and neck (SCCHN), hypoxia is considered a pivotal physiological modulator for malignant progression, whereby the plasminogen activation system is involved in overlapping functions such as the shaping of the extracellular matrix, cell proliferation and signal transduction. Since little is known about reoxygenation and the plasminogen activation system in SCCHN, three human SCCHN cell lines (BHY, FaDu, and CAL27) and a non-transformed control cell line (VH7) were exposed to hypoxic (<0.5% O2) conditions for up to 72 h and subsequently reoxygenated for 24 h at normoxic conditions. The mRNA expression of the urokinase-type plasminogen activator (uPA), the plasminogen activator inhibitor type-1 (PAI-1) and the urokinase-type plasminogen activator receptor (uPAR) was assessed by means of real-time semi-quantitative RT-PCR, and the protein expression was determined by immunoenzymometric quantification (ELISA). Both hypoxia and reoxygenation induced statistically significant changes in uPA, PAI-1 and uPAR mRNA and protein levels in the various cell lines investigated, showing that oxygen tension is a strong modulator of the plasminogen activation system in vitro. However, no uniform correlation pattern was found between the mRNA and protein levels analysed over all three time-points (24, 48, and 72 h) and oxygen treatment variants (N, H, R) nor according to oxygen treatment conditions over all three time-points. Changes in oxygen tension could therefore be modulating the fragile balance between the various components of the plasminogen activation system in SSCHN ultimately leading to an increased tumour matrix disruption, alterations in cell invasiveness, and the dissemination of tumour cells to distant organs.

Effect of propofol on hypoxia re-oxygenation induced neuronal cell damage in vitro*.

PubMed

Huang, Y; Zitta, K; Bein, B; Scholz, J; Steinfath, M; Albrecht, M

2013-01-01

Propofol may protect neuronal cells from hypoxia re-oxygenation injury, possibly via an antioxidant actions under hypoxic conditions. This study investigated the molecular effects of propofol on hypoxia-induced cell damage using a neuronal cell line. Cultured human IMR-32 cells were exposed to propofol (30 μm) and biochemical and molecular approaches were used to assess cellular effects. Propofol significantly reduced hypoxia-mediated increases in lactate dehydrogenase, a marker of cell damage (mean (SD) for normoxia: 0.39 (0.07) a.u.; hypoxia: 0.78 (0.21) a.u.; hypoxia+propofol: 0.44 (0.17) a.u.; normoxia vs hypoxia, p<0.05; hypoxia vs hypoxia+propofol, p<0.05), reactive oxygen species and hydrogen peroxide. Propofol also diminished the morphological signs of cell damage. Increased amounts of catalase, which degrades hydrogen peroxide, were detected under hypoxic conditions. Propofol decreased the amount of catalase produced, but increased its enzymatic activity. Propofol protects neuronal cells from hypoxia re-oxygenation injury, possibly via a combined direct antioxidant effect along with induced cellular antioxidant mechanisms. Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

Use of dissolved oxygen modeling results in the management of river quality

USGS Publications Warehouse

Rickert, D.A.

1984-01-01

In 1973, the U.S. Geological Survey initiated a study of the Willamette River, Oregon, to determine the major causes of dissolved oxygen (DO) depletion, and whether advanced treatment of municipal wastewaters was needed to achieve the DO standards. The study showed that rates of carbonaceous decay were low (kr = 0.03-0.06/day) and that point-source loadings of carbonaceous biochemical oxygen demand (BOD) accounted for less than one-third of the satisfied oxygen demand. Nitrification of industrially discharged ammonia was the dominant cause of DO depletion. The study led to the calibration and verification of a steady-state DO model which was used to examine selected scenarios of BOD loading, ammonia loading, and flow augmentation. In 1976, the modeling projections for the Willamette River were presented to resource managers. A review in 1981 indicated that the State of Oregon had instituted an effluent standard on the major discharger of ammonia, rescinded an order for all municipal wastewaters to receive advanced secondary treatment by 1980, and more fully acknowledged the need for flow augmentation during summer to attain the DO standards.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Wabash River, Huntington County, Indiana

USGS Publications Warehouse

Crawford, Charles G.; Wilber, William G.; Peters, James G.

1980-01-01

A digital model calibrated to conditions in the Wabash River in Huntington County, Ind., was used to predict alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditons, summer and winter low flows. The major point-source waste load affecting the Wabash River in Huntington County is the Huntington wastewater-treatment facility. The most significnt factor potentially affecting the dissolved-oxygen concentration during summer low flows is nitrification. However, nitrification should not be a limiting factor on the allowable nitrogenous and carbonaceous waste loads for the Huntington wastewater-treatment facility during summer low flows if the ammonia-nitrogen toxicity standard for Indiana streams is met. The disolved-oxygen standard for Indiana stream, an average of 5.0 milligrams per liter, should be met during summer and winter low flows if the National Pollution Discharge Elimination System 's 5-day, carbonaceous biochemical-oxygen demands of a monthly average concentration of 30 milligrams per liter and a maximum weekly average of 45 milligrams per liter are not exceeded. 

Characterization of water quality and simulation of temperature, nutrients, biochemical oxygen demand, and dissolved oxygen in the Wateree River, South Carolina, 1996-98

USGS Publications Warehouse

Feaster, Toby D.; Conrads, Paul

2000-01-01

In May 1996, the U.S. Geological Survey entered into a cooperative agreement with the Kershaw County Water and Sewer Authority to characterize and simulate the water quality in the Wateree River, South Carolina. Longitudinal profiling of dissolved-oxygen concentrations during the spring and summer of 1996 revealed dissolved-oxygen minimums occurring upstream from the point-source discharges. The mean dissolved-oxygen decrease upstream from the effluent discharges was 2.0 milligrams per liter, and the decrease downstream from the effluent discharges was 0.2 milligram per liter. Several theories were investigated to obtain an improved understanding of the dissolved-oxygen dynamics in the upper Wateree River. Data suggest that the dissolved-oxygen concentration decrease is associated with elevated levels of oxygen-consuming nutrients and metals that are flowing into the Wateree River from Lake Wateree. Analysis of long-term streamflow and water-quality data collected at two U.S. Geological Survey gaging stations suggests that no strong correlation exists between streamflow and dissolved-oxygen concentrations in the Wateree River. However, a strong negative correlation does exist between dissolved-oxygen concentrations and water temperature. Analysis of data from six South Carolina Department of Health and Environmental Control monitoring stations for 1980.95 revealed decreasing trends in ammonia nitrogen at all stations where data were available and decreasing trends in 5-day biochemical oxygen demand at three river stations. The influence of various hydrologic and point-source loading conditions on dissolved-oxygen concentrations in the Wateree River were determined by using results from water-quality simulations by the Branched Lagrangian Transport Model. The effects of five tributaries and four point-source discharges were included in the model. Data collected during two synoptic water-quality samplings on June 23.25 and August 11.13, 1997, were used to calibrate and validate the Branched Lagrangian Transport Model. The data include dye-tracer concentrations collected at six locations, stream-reaeration data collected at four locations, and water-quality and water-temperature data collected at nine locations. Hydraulic data for the Branched Lagrangian Transport Model were simulated by using the U.S. Geological Survey BRANCH one-dimensional, unsteady-flow model. Data that were used to calibrate and validate the BRANCH model included time-series of water-level and streamflow data at three locations. The domain of the hydraulic model and the transport model was a 57.3- and 43.5-mile reach of the river, respectively. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to changes in the boundary concentration inputs of water temperature and dissolved oxygen followed by sensitivity to the change in streamflow. A 35-percent increase in streamflow resulted in a negative normalized sensitivity index, indicating a decrease in dissolved-oxygen concentrations. The simulated dissolved-oxygen concentrations showed no significant sensitivity to changes in model input rate kinetics. To demonstrate the utility of the Branched Lagrangian Transport Model of the Wateree River, the model was used to simulate several hydrologic and water-quality scenarios to evaluate the effects on simulated dissolved-oxygen concentrations. The first scenario compared the 24-hour mean dissolved-oxygen concentrations for August 13, 1997, as simulated during the model validation, with simulations using two different streamflow patterns. The mean streamflow for August 13, 1997, was 2,000 cubic feet per second. Simulations were run using mean streamflows of 1,000 and 1,400 cubic feet per second while keeping the water-quality boundary conditions the same as were used during the validation simulations. When compared t

Simulation of Liquid Level, Temperature and Pressure Inside a 2000 Liter Liquid Hydrogen Tank During Truck Transportation

NASA Astrophysics Data System (ADS)

Takeda, Minoru; Nara, Hiroyuki; Maekawa, Kazuma; Fujikawa, Shizuichi; Matsuno, Yu; Kuroda, Tsuneo; Kumakura, Hiroaki

Hydrogen is an ultimate energy source because only water is produced after the chemical reaction of hydrogen and oxygen. In the near future, a large amount of hydrogen, produced using sustainable/renewable energy, is expected to be consumed. Since liquid hydrogen (LH2) has the advantage of high storage efficiency, it is expected to be the ultimate medium for the worldwide storage and transportation of large amounts of hydrogen. To make a simulation model of the sloshing of LH2 inside a 2000 liter tank, simulation analyses of LH2 surface oscillation, temperature and pressure inside the tank during a truck transportation have been carried out using a multipurpose software ANSYS CFX. Numerical results are discussed in comparison with experimental results.

Plasma Pyrolysis Assembly Regeneration Evaluation

NASA Technical Reports Server (NTRS)

Medlen, Amber; Abney, Morgan B.; Miller, Lee A.

2011-01-01

In April 2010 the Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS). This technology requires hydrogen to recover oxygen from carbon dioxide. This results in the production of water and methane. Water is electrolyzed to provide oxygen to the crew. Methane is vented to space resulting in a loss of valuable hydrogen and unreduced carbon dioxide. This is not critical for ISS because of the water resupply from Earth. However, in order to have enough oxygen for long-term missions, it will be necessary to recover the hydrogen to maximize oxygen recovery. Thus, the Plasma Pyrolysis Assembly (PPA) was designed to recover hydrogen from methane. During operation, the PPA produces small amounts of carbon that can ultimately reduce performance by forming on the walls and windows of the reactor chamber. The carbon must be removed, although mechanical methods are highly inefficient, thus chemical methods are of greater interest. The purpose of this effort was to determine the feasibility of chemically removing the carbon from the walls and windows of a PPA reactor using a pure carbon dioxide stream.

A Comprehensive X-Ray Absorption Model for Atomic Oxygen

NASA Technical Reports Server (NTRS)

Gorczyca, T. W.; Bautista, M. A.; Hasoglu, M. F.; Garcia, J.; Gatuzz, E.; Kaastra, J. S.; Kallman, T. R.; Manson, S. T.; Mendoza, C.; Raassen, A. J. J.;

Synthesis, crystal structure and physico-chemical properties of the new quaternary oxide Sr 5BiNi 2O 9.6

NASA Astrophysics Data System (ADS)

Novitskaya, Mariya; Makhnach, Leonid; Ivashkevich, Ludmila; Pankov, Vladimir; Klein, Holger; Rageau, Amélie; David, Jérémy; Gemmi, Mauro; Hadermann, Joke; Strobel, Pierre

2011-12-01

A new black quaternary oxide Sr 5BiNi 2O 9.6 was synthesized by solid state reaction at 1200 °C. Its structure was solved by electron crystallography and X-ray powder refinement, yielding a tetragonal structure with space group I4/ mmm, a=5.3637 (2) Å, c=17.5541(5) Å, Z=4. The structure can be described as a stacking of (Bi,Sr)-O rocksalt slabs and SrNiO 3- δ perovskite slabs. The initial nickel valence is close to +3.1. Thermogravimetry and high-temperature oxygen coulometry showed that this compound has variable oxygen content as a function of temperature and oxygen pressure, and ultimately decomposes when heated in low oxygen pressure above 800 °C. It is a metallic conductor with n-type conduction. Its thermoelectric power was determined and found to be -20 and -38 μV/K at 300 and 650 °C, respectively. Magnetic measurements confirm the nickel valence close to +3 and show evidence of magnetic ordering at 20 K.

Lego Bricks and the Octet Rule: Molecular Models for Biochemical Pathways with Plastic, Interlocking Toy Bricks

ERIC Educational Resources Information Center

Lin, Henry J.; Lehoang, Jennifer; Kwan, Isabel; Baghaee, Anita; Prasad, Priya; Ha-Chen, Stephanie J.; Moss, Tanesha; Woods, Jeremy D.

2018-01-01

The 8 studs on a 2 × 4 Lego brick conveniently represent the outer shell of electrons for carbon, nitrogen, and oxygen atoms. We used Lego bricks to model these atoms, which are then joined together to form molecules by following the Lewis octet rule. A variety of small biological molecules can be modeled in this way, such as most amino acids,…

Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species Production in Nickel Hyperaccumulator Alyssum murale*

PubMed Central

Agrawal, Bhavana; Czymmek, Kirk J.; Sparks, Donald L.; Bais, Harsh P.

2013-01-01

Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation. PMID:23322782

Transient Influx of nickel in root mitochondria modulates organic acid and reactive oxygen species production in nickel hyperaccumulator Alyssum murale.

PubMed

Agrawal, Bhavana; Czymmek, Kirk J; Sparks, Donald L; Bais, Harsh P

2013-03-08

Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation.

Biochemical responses of filamentous algae in different aquatic ecosystems in South East Turkey and associated water quality parameters.

PubMed

Çelekli, Abuzer; Arslanargun, Hamdullah; Soysal, Çiğdem; Gültekin, Emine; Bozkurt, Hüseyin

2016-11-01

To the best of our knowledge, any study about biochemical response of filamentous algae in the complex freshwater ecosystems has not been found in the literature. This study was designed to explore biochemical response of filamentous algae in different water bodies from May 2013 to October 2014, using multivariate approach in the South East of Turkey. Environmental variables were measured in situ: water temperature, oxygen concentration, saturation, conductivity, salinity, pH, redox potential, and total dissolved solid. Chemical variables of aqueous samples and biochemical compounds of filamentous algae were also measured. It was found that geographic position and anthropogenic activities had strong effect on physico-chemical variables of water bodies. Variation in environmental conditions caused change in algal biomass composition due to the different response of filamentous species, also indicated by FTIR analysis. Biochemical responses not only changed from species to species, but also varied for the same species at different sampling time and sampling stations. Multivariate analyses showed that heavy metals, nutrients, and water hardness were found as the important variables governing the temporal and spatial succession and biochemical compounds. Nutrients, especially nitrate, could stimulate pigment and total protein production, whereas high metal content had adverse effects. Amount of malondialdehyde (MDA), H2O2, total thiol groups, total phenolic compounds, proline, total carbohydrate, and metal bioaccumulation by filamentous algae could be closely related with heavy metals in the ecosystems. Significant increase in MDA, H2O2, total thiol group, total phenolic compounds, and proline productions by filamentous algae and chlorosis phenomenon seemed to be an important strategy for alleviating environmental factors-induced oxidative stress as biomarkers. Copyright © 2016 Elsevier Inc. All rights reserved.

The optimization air separation plants for combined cycle MHD-power plant applications

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Springmann, H.; Greenberg, R.

1980-01-01

Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

The Complex Relationship of Extracorporeal Membrane Oxygenation and Acute Kidney Injury: Causation or Association?

PubMed

Kilburn, Daniel J; Shekar, Kiran; Fraser, John F

2016-01-01

Extracorporeal membrane oxygenation (ECMO) is a modified cardiopulmonary bypass (CPB) circuit capable of providing prolonged cardiorespiratory support. Recent advancement in ECMO technology has resulted in increased utilisation and clinical application. It can be used as a bridge-to-recovery, bridge-to-bridge, bridge-to-transplant, or bridge-to-decision. ECMO can restitute physiology in critically ill patients, which may minimise the risk of progressive multiorgan dysfunction. Alternatively, iatrogenic complications of ECMO clearly contribute to worse outcomes. These factors affect the risk : benefit ratio of ECMO which ultimately influence commencement/timing of ECMO. The complex interplay of pre-ECMO, ECMO, and post-ECMO pathophysiological processes are responsible for the substantial increased incidence of ECMO-associated acute kidney injury (EAKI). The development of EAKI significantly contributes to morbidity and mortality; however, there is a lack of evidence defining a potential benefit or causative link between ECMO and AKI. This area warrants investigation as further research will delineate the mechanisms involved and subsequent strategies to minimise the risk of EAKI. This review summarizes the current literature of ECMO and AKI, considers the possible benefits and risks of ECMO on renal function, outlines the related pathophysiology, highlights relevant investigative tools, and ultimately suggests an approach for future research into this under investigated area of critical care.

Field and laboratory studies reveal interacting effects of stream oxygenation and warming on aquatic ectotherms.

PubMed

Verberk, Wilco C E P; Durance, Isabelle; Vaughan, Ian P; Ormerod, Steve J

2016-05-01

Aquatic ecological responses to climatic warming are complicated by interactions between thermal effects and other environmental stressors such as organic pollution and hypoxia. Laboratory experiments have demonstrated how oxygen limitation can set heat tolerance for some aquatic ectotherms, but only at unrealistic lethal temperatures and without field data to assess whether oxygen shortages might also underlie sublethal warming effects. Here, we test whether oxygen availability affects both lethal and nonlethal impacts of warming on two widespread Eurasian mayflies, Ephemera danica, Müller 1764 and Serratella ignita (Poda 1761). Mayfly nymphs are often a dominant component of the invertebrate assemblage in streams, and play a vital role in aquatic and riparian food webs. In the laboratory, lethal impacts of warming were assessed under three oxygen conditions. In the field, effects of oxygen availability on nonlethal impacts of warming were assessed from mayfly occurrence in 42 293 UK stream samples where water temperature and biochemical oxygen demand were measured. Oxygen limitation affected both lethal and sublethal impacts of warming in each species. Hypoxia lowered lethal limits by 5.5 °C (±2.13) and 8.2 °C (±0.62) for E. danica and S. ignita respectively. Field data confirmed the importance of oxygen limitation in warmer waters; poor oxygenation drastically reduced site occupancy, and reductions were especially pronounced under warm water conditions. Consequently, poor oxygenation lowered optimal stream temperatures for both species. The broad concordance shown here between laboratory results and extensive field data suggests that oxygen limitation not only impairs survival at thermal extremes but also restricts species abundance in the field at temperatures well below upper lethal limits. Stream oxygenation could thus control the vulnerability of aquatic ectotherms to global warming. Improving water oxygenation and reducing pollution can provide key facets of climate change adaptation for running waters. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Evaluation of the adhesion on the nano-scaled polymeric film systems.

PubMed

Park, Tae Sung; Park, Ik Keun; Yoshida, Sanichiro

2017-04-01

We applied scanning acoustic microscopy known as the V(z) curve technique to photoresist thin-film systems for the evaluation of the adhesive strength at the film-substrate interface. Through the measurement of the SAW (Surface Acoustic Wave) velocity, the V(z) curve analysis allows us to quantify the stiffness of the film-substrate interface. In addition, we conducted a nano-scratch test to quantify the ultimate strength of the adhesion through the evaluation of the critical load. To vary the adhesive conditions, we prepared thin-film specimens with three different types of pre-coating surface treatments, i.e., oxygen-plasma bombardment, HMDS (Hexametyldisilazane) treatment and untreated. The magnitudes of the quantified stiffness and ultimate strength are found consistent with each other for all the specimens tested, indicating that the pre-coating surface treatment can strengthen both the stiffness and ultimate strength of the adhesion. The results of this study demonstrate the usefulness of the V(Z) analysis as a nondestructive method to evaluate the adhesion strength of nano-structured thin-film systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97

USGS Publications Warehouse

Feaster, Toby D.; Conrads, Paul; Guimaraes, Wladmir B.; Sanders, Curtis L.; Bales, Jerad D.

2003-01-01

Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3) fully loaded (in accordance with South Carolina Department of Health and Environmental Control National Discharge Elimination System permits). Results indicate that the 24-hour mean and minimum dissolved-oxygen concentrations for August 24, 1996, changed from the no-load condition within a range of - 0.33 to 0.02 milligram per liter and - 0.48 to 0.00 milligram per liter, respectively. Fully permitted loading conditions changed the 24-hour mean and minimum dissolved-oxygen concentrations from - 0.88 to 0.04 milligram per liter and - 1.04 to 0.00 milligram per liter, respectively. A second scenario included the addition of a point-source discharge of 25 million gallons per day to the August 1996 calibration conditions. The discharge was added at S.C. Highway 5 or at a location near Culp Island (about 4 miles downstream from S.C. Highway 5) and had no significant effect on the daily mean and minimum dissolved-oxygen concentration. A third scenario evaluated the phosphorus loading into Fishing Creek Reservoir; four loading conditions of phosphorus into Catawba River were simulated. The four conditions included fully permitted and actual loading conditions, removal of all point sources from the Catawba River, and removal of all point and nonpoint sources from Sugar Creek. Removing the point-source inputs on the Catawba River and the point and nonpoint sources in Sugar Creek reduced the organic phosphorus and orthophosphate loadings to Fishing Creek Reservoir by 78 and 85 percent, respectively.

The Development of Combined Raman Spectroscopy-Optical Coherence Tomography and Application for Skin Cancer Diagnosis

NASA Astrophysics Data System (ADS)

Patil, Chetan

2009-11-01

Optical spectroscopy and imaging have shown promise for performing rapid, non-invasive disease detection and diagnosis in vivo. Independently, Raman Spectroscopy (RS) has demonstrated the ability to perform diagnosis of epithelial cancers such the cervix with excellent overall classification accuracy due to the inherent biochemical specificity of the technique, however relating features of tissue morphology with techniques such as Raman mapping is clinically impractical due to the weak nature of the scattering phenomena resulting in prohibitively long acquisition times. Optical Coherence Tomography (OCT), on the other hand, has demonstrated the ability to perform real-time, high-resolution, cross-sectional imaging of the microstructural characteristics of disease, but typically lacks molecularly specific information that can assist in classifying pathological lesions. We present the development of a combined Raman Spectroscopy-OCT (RS-OCT) instrument capable of compensating for the limitations of each technique individually and performing both biochemical and microstructural evaluation of tissues. We will include the design and development of benchtop RS-OCT implementations based on independent 785 nm Raman and 1310 nm time-domain OCT system backbones, as well as with a 785nm Raman / 850nm spectral-domain OCT setup employing an integrated detection arm. These systems motivated the ultimate design of a clinical RS-OCT system for application in dermatology. In order to aid in the development of our Raman spectral processing and classification methods, we conducted a simultaneous pilot study in which RS alone was used to measure basal and squamous cell carcinomas. We will present the initial results from our clinical experiences with the combined RS-OCT device, and include a discussion of spectral classification and the ultimate potential of combined RS-OCT for skin cancer diagnosis.

Potential role of the glycolytic oscillator in acute hypoxia in tumors

NASA Astrophysics Data System (ADS)

Che Fru, Leonard; Adamson, Erin B.; Campos, David D.; Fain, Sean B.; Jacques, Steven L.; van der Kogel, Albert J.; Nickel, Kwang P.; Song, Chihwa; Kimple, Randall J.; Kissick, Michael W.

2015-12-01

Tumor acute hypoxia has a dynamic component that is also, at least partially, coherent. Using blood oxygen level dependent magnetic resonance imaging, we observed coherent oscillations in hemoglobin saturation dynamics in cell line xenograft models of head and neck squamous cell carcinoma. We posit a well-established biochemical nonlinear oscillatory mechanism called the glycolytic oscillator as a potential cause of the coherent oscillations in tumors. These data suggest that metabolic changes within individual tumor cells may affect the local tumor microenvironment including oxygen availability and therefore radiosensitivity. These individual cells can synchronize the oscillations in patches of similar intermediate glucose levels. These alterations have potentially important implications for radiation therapy and are a potential target for optimizing the cancer response to radiation.

Development of anaerobic digestion methods for palm oil mill effluent (POME) treatment.

PubMed

Poh, P E; Chong, M F

2009-01-01

Palm oil mill effluent (POME) is a highly polluting wastewater that pollutes the environment if discharged directly due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentration. Anaerobic digestion has been widely used for POME treatment with large emphasis placed on capturing the methane gas released as a product of this biodegradation treatment method. The anaerobic digestion method is recognized as a clean development mechanism (CDM) under the Kyoto protocol. Certified emission reduction (CER) can be obtained by using methane gas as a renewable energy. This review aims to discuss the various anaerobic treatments of POME and factors that influence the operation of anaerobic treatment. The POME treatment at both mesophilic and thermophilic temperature ranges are also analyzed.

Reactive oxygen species-activated nanomaterials as theranostic agents.

PubMed

Kim, Kye S; Lee, Dongwon; Song, Chul Gyu; Kang, Peter M

2015-01-01

Reactive oxygen species (ROS) are generated from the endogenous oxidative metabolism or from exogenous pro-oxidant exposure. Oxidative stress occurs when there is excessive production of ROS, outweighing the antioxidant defense mechanisms which may lead to disease states. Hydrogen peroxide (H2O2) is one of the most abundant and stable forms of ROS, implicated in inflammation, cellular dysfunction and apoptosis, which ultimately lead to tissue and organ damage. This review is an overview of the role of ROS in different diseases. We will also examine ROS-activated nanomaterials with emphasis on hydrogen peroxide, and their potential medical implications. Further development of the biocompatible, stimuli-activated agent responding to disease causing oxidative stress, may lead to a promising clinical use.

An Investigation of the Reverse Water Gas Shift Process and Operating Alternatives

NASA Technical Reports Server (NTRS)

Whitlow, Jonathan E.

2002-01-01

The Reverse Water Gas Shift (RWGS) process can produce water and ultimately oxygen through electrolysis. This technology is being investigated for possible use in the exploration of Mars as well as a potential process to aid in the regeneration of oxygen from carbon dioxide. The initial part of this report summarizes the results obtained from operation of the RWGS process at Kennedy Space Center during May and June of this year. It has been demonstrated that close to complete conversion can be achieved with the RWGS process under certain operating conditions. The report also presents results obtained through simulation for an alternative staged configuration for RWGS which eliminates the recycle compressor. This configuration looks promising and hence seems worthy of experimental investigation.

Sediment oxygen demand in the Saddle River and Salem River watersheds, New Jersey, July-August 2008

USGS Publications Warehouse

Heckathorn, Heather A.; Gibs, Jacob

2010-01-01

Many factors, such as river depth and velocity, biochemical oxygen demand, and algal productivity, as well as sediment oxygen demand, can affect the concentration of dissolved oxygen in the water column. Measurements of sediment oxygen demand, in conjunction with those of other water-column water-quality constituents, are useful for quantifying the mechanisms that affect in-stream dissolved-oxygen concentrations. Sediment-oxygen-demand rates are also needed to develop and calibrate a water-quality model being developed for the Saddle River and Salem River Basins in New Jersey to predict dissolved-oxygen concentrations. This report documents the methods used to measure sediment oxygen demand in the Saddle River and Salem River watersheds along with the rates of sediment oxygen demand that were obtained during this investigation. In July and August 2008, sediment oxygen demand was measured in situ in the Saddle River and Salem River watersheds. In the Saddle River Basin, sediment oxygen demand was measured twice at two sites and once at a third location; in the Salem River Basin, sediment oxygen demand was measured three times at two sites and once at a third location. In situ measurements of sediment oxygen demand in the Saddle River and Salem River watersheds ranged from 0.8 to 1.4 g/m2d (grams per square meter per day) and from 0.6 to 7.1 g/m2d at 20 degrees Celsius, respectively. Except at one site in this study, rates of sediment oxygen demand generally were low. The highest rate of sediment oxygen demand measured during this investigation, 7.1 g/m2d, which occurred at Courses Landing in the Salem River Basin, may be attributable to the consumption of oxygen by a large amount of organic matter (54 grams per kilogram as organic carbon) in the streambed sediments or to potential error during data collection. In general, sediment oxygen demand increased with the concentration of organic carbon in the streambed sediments. Repeated measurements made 6 to 7 days apart at the same site locations resulted in similar values.

High Precision Continuous and Real-Time Measurement of Atmospheric Oxygen Using Cavity Ring-Down Spectroscopy

NASA Astrophysics Data System (ADS)

Kim-Hak, David; Leuenberger, Markus; Berhanu, Tesfaye; Nyfeler, Peter; Hoffnagle, John; Sun, Minghua

2017-04-01

Oxygen (O2) is a major and vital component of the Earth atmosphere representing about 21% of its composition. It is consumed or produced through biochemical processes such as combustion, respiration, and photosynthesis and can be used as a top-down constraint on the carbon cycle. The observed variations of oxygen in the atmosphere are relatively small, in the order of a few ppm's. This presents the main technical challenge for the measurement since a very high level of precision on a large background is required. Only few analytical methods including mass spectrometry, fuel, ultraviolet[1] and paramagnetic cells are capable of achieving it. Here we present new developments of a high-precision gas analyzer that utilizes the technique of Cavity Ring-Down Spectroscopy to measure oxygen concentration and its oxygen isotope ratio 18O/16O. Its compact and ruggedness design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous monitoring of atmospheric oxygen level. Measurements have a 1-σ 5-minute averaging precision of 1-2 ppm for O2 over a dynamic range of 0-50%. We will present comparative test results of this instrument against the incumbent technologies such as the mass spectrometer and the paramagnetic cell. In addition, we will demonstrate its long-term stability from a field deployment in Switzerland.

Cisplatin toxicity reduced in human cultured renal tubular cells by oxygen pretreatment.

PubMed

Kaeidi, Ayat; Rasoulian, Bahram; Hajializadeh, Zahra; Pourkhodadad, Soheila; Rezaei, Maryam

2013-01-01

Cisplatin is an effective and widely used chemotherapy agent and its side effects, particularly nephrotoxicity, limit its usage and related platinum-based drugs. Cisplatin nephrotoxicity is mainly due to extremely increase in reactive oxygen species (ROS) generation leading to kidney tubular cell death. Preconditioning with oxidative stress has been demonstrated to stimulate the cellular adaptation to subsequent severe oxidative stress. Short term oxygen pre-exposure as a mild oxidative stress may enhance some endogenous defense mechanisms, so its effect on Cisplatin induced cell death was investigated in present research. We studied the effects of hyperoxic environment pre-exposure on Cisplatin toxicity in an in-vitro model of cultured human embryonic tubular epithelial cells (AD293). Viability of AD293 cells, as evaluated by MTT-assay, was affected by Cisplatin in a time (1-4 h) dependent model. Biochemical markers of cell apoptosis were evaluated using immunoblotting. Pretreatment with nearly pure oxygen (≥90%) for 2 h significantly reduced the level of cell damage. Activated caspase 3 and Bax/Bcl-2 ratio were significantly increased in Cisplatin-treated cells. Oxygen pretreatment inhibited caspase 3 activation and decreased Bax/Bcl-2 ratio. Oxygen pre-treatment itself not showed any cytotoxicity in exposure times up to 3 h. Our data indicate that hyperoxic preconditioning reduces Cisplatin toxicity in cultured human tubular epithelial cells. The exact mechanism of protection is unclear, though enhancement of some endogenous defense mechanisms and subsequently scavenging of free oxygen radicals may play an important role.

Atomic Oxygen Lamp Cleaning Facility Fabricated and Tested

NASA Technical Reports Server (NTRS)

Sechkar, Edward A.; Stueber, Thomas J.

1999-01-01

NASA Lewis Research Center's Atomic Oxygen Lamp Cleaning Facility was designed to produce an atomic oxygen plasma within a metal halide lamp to remove carbon-based contamination. It is believed that these contaminants contribute to the high failure rate realized during the production of these lamps. The facility is designed to evacuate a metal halide lamp and produce a radio frequency generated atomic oxygen plasma within it. Oxygen gas, with a purity of 0.9999 percent and in the pressure range of 150 to 250 mtorr, is used in the lamp for plasma generation while the lamp is being cleaned. After cleaning is complete, the lamp can be backfilled with 0.9999-percent pure nitrogen and torch sealed. The facility comprises various vacuum components connected to a radiation-shielded box that encloses the bulb during operation. Radiofrequency power is applied to the two parallel plates of a capacitor, which are on either side of the lamp. The vacuum pump used, a Leybold Trivac Type D4B, has a pumping speed of 4-m3/hr, has an ultimate pressure of <8x10-4, and is specially adapted for pure oxygen service. The electronic power supply, matching network, and controller (500-W, 13.56-MHz) used to supply the radiofrequency power were purchased from RF Power Products Inc. Initial test results revealed that this facility could remove the carbon-based contamination from within bulbs.

Anoxygenic photosynthesis modulated Proterozoic oxygen and sustained Earth's middle age

PubMed Central

Johnston, D. T.; Wolfe-Simon, F.; Pearson, A.; Knoll, A. H.

2009-01-01

Molecular oxygen (O2) began to accumulate in the atmosphere and surface ocean ca. 2,400 million years ago (Ma), but the persistent oxygenation of water masses throughout the oceans developed much later, perhaps beginning as recently as 580–550 Ma. For much of the intervening interval, moderately oxic surface waters lay above an oxygen minimum zone (OMZ) that tended toward euxinia (anoxic and sulfidic). Here we illustrate how contributions to primary production by anoxygenic photoautotrophs (including physiologically versatile cyanobacteria) influenced biogeochemical cycling during Earth's middle age, helping to perpetuate our planet's intermediate redox state by tempering O2 production. Specifically, the ability to generate organic matter (OM) using sulfide as an electron donor enabled a positive biogeochemical feedback that sustained euxinia in the OMZ. On a geologic time scale, pyrite precipitation and burial governed a second feedback that moderated sulfide availability and water column oxygenation. Thus, we argue that the proportional contribution of anoxygenic photosynthesis to overall primary production would have influenced oceanic redox and the Proterozoic O2 budget. Later Neoproterozoic collapse of widespread euxinia and a concomitant return to ferruginous (anoxic and Fe2+ rich) subsurface waters set in motion Earth's transition from its prokaryote-dominated middle age, removing a physiological barrier to eukaryotic diversification (sulfide) and establishing, for the first time in Earth's history, complete dominance of oxygenic photosynthesis in the oceans. This paved the way for the further oxygenation of the oceans and atmosphere and, ultimately, the evolution of complex multicellular organisms. PMID:19805080

Anoxygenic photosynthesis modulated Proterozoic oxygen and sustained Earth's middle age.

PubMed

Johnston, D T; Wolfe-Simon, F; Pearson, A; Knoll, A H

2009-10-06

Molecular oxygen (O(2)) began to accumulate in the atmosphere and surface ocean ca. 2,400 million years ago (Ma), but the persistent oxygenation of water masses throughout the oceans developed much later, perhaps beginning as recently as 580-550 Ma. For much of the intervening interval, moderately oxic surface waters lay above an oxygen minimum zone (OMZ) that tended toward euxinia (anoxic and sulfidic). Here we illustrate how contributions to primary production by anoxygenic photoautotrophs (including physiologically versatile cyanobacteria) influenced biogeochemical cycling during Earth's middle age, helping to perpetuate our planet's intermediate redox state by tempering O(2) production. Specifically, the ability to generate organic matter (OM) using sulfide as an electron donor enabled a positive biogeochemical feedback that sustained euxinia in the OMZ. On a geologic time scale, pyrite precipitation and burial governed a second feedback that moderated sulfide availability and water column oxygenation. Thus, we argue that the proportional contribution of anoxygenic photosynthesis to overall primary production would have influenced oceanic redox and the Proterozoic O(2) budget. Later Neoproterozoic collapse of widespread euxinia and a concomitant return to ferruginous (anoxic and Fe(2+) rich) subsurface waters set in motion Earth's transition from its prokaryote-dominated middle age, removing a physiological barrier to eukaryotic diversification (sulfide) and establishing, for the first time in Earth's history, complete dominance of oxygenic photosynthesis in the oceans. This paved the way for the further oxygenation of the oceans and atmosphere and, ultimately, the evolution of complex multicellular organisms.

Does chewing coca leaves influence physiology at high altitude?

PubMed

Casikar, V; Mujica, E; Mongelli, M; Aliaga, J; Lopez, N; Smith, C; Bartholomew, F

2010-07-01

Andean Indians have used coca leaves (Erythroxylon coca and related species) for centuries to enhance physical performance. The benefits and disadvantages of using coca leaf have been a subject of many political debates. The aim of this study was to investigate the effects of chewing coca leaves on biochemical and physiological parameters. Cutaneous microdialysis catheters were used to estimate systemic biochemical changes. We subjected 10 healthy adult males (local residents) in Cajamarca (Peru, altitude 2700 m) to a standardised exercise routine on a stationary cycle ergometer. The blood pressure, oxygen saturation (digital), pulse, VO2 max and ECG (Holter monitor) were recorded before the exercise. Cutaneous microdialysis catheters were introduced in the forearm. The subjects were given to chew 8 g of coca leaves with a small amount of lime. They were then placed on the cycle ergometer for 20 min. Blood pressure, oxygen saturation, pulse, ECG and VO2 max were recorded. Pyruvate, glucose, lactate, glycerol and glutamate levels were estimated. Oxygen saturation, blood pressure, and pulse rate did not show any significant changes between the two groups. Glucose levels showed hyperglycaemic response. Glycerol, Lactate and Pyruvate increased. Glutamate remained unchanged. Similar changes were not seen in the controls. These results suggest that coca leaves have blocked the glycolytic pathway of glucose oxidation resulting in accumulation of glucose and pyruvate. The energy requirement for exercise is being met with beta-oxidation of fatty acids. The glycerol released was also getting accumulated since its pathway for oxidation was blocked. These experimental findings suggest that chewing coca leaves is beneficial during exercise and that the effects are felt over a prolonged period of sustained physical activity.

Demonstrate a Low Biochemical Oxygen Demand Aircraft Deicing Fluid

DTIC Science & Technology

2013-03-01

Technologies International, LTD for collection and recycling of fluids. Spent fluid, diluted with any water, slush or snow removed from the aircraft or...Resistance Unmated only – some failures Voltage Withstand Testing Unmated only – some failures Plastic Windows Crazing Effect Pass The testing did result...At Joint Base McGuire-Dix-Lakehurst, however, waste PG is currently collected with a vacuum truck and recycled . Factors such as the market demand

Demonstrate a Low Biochemical Oxygen Demand Aircraft Deicing Fluid

DTIC Science & Technology

2013-03-04

Technologies International, LTD for collection and recycling of fluids. Spent fluid, diluted with any water, slush or snow removed from the aircraft or...Resistance Unmated only – some failures Voltage Withstand Testing Unmated only – some failures Plastic Windows Crazing Effect Pass The testing did result...At Joint Base McGuire-Dix-Lakehurst, however, waste PG is currently collected with a vacuum truck and recycled . Factors such as the market demand

Photographic Processing Interpretation Facility Wastewater Conceptual Treatment Design.

DTIC Science & Technology

1983-03-01

Total Chromium (Cr) - - - ɘ.05 - Copper (Cu) - - - ɘ.05 - Iron (Fe) - - - - - Manganese (Mn) - - - ɘ.03 - Mercury (Hg) - - - ɘ.004 - Potassium (K...8.3 - Silver (Ag) 2.2 7.0 17 0.15 2.2 Sodium (Na) - - - 8.2 - Zinc (Zn) - - - 0.12 - Biochemical Oxygen " Demand (BOD_) - - - 40 - Sulfate (SO...nonconventional pollutants include boron, dissolved sol i halides, iron, ammonia, nitrogen, phenols, sulfate and TOC. ,P,, 99 percent of the 11,000

Aerobic Denitrification as an Innovative Method for In-Situ Biological Remediation of Contaminated Subsurface Sites

DTIC Science & Technology

1989-01-01

presumed subsurface conditon; * more rapid mineralization of organics and secondary metabolites ; * decrease in the biochemical oxygen demand and the...additon of nitrate would result in the more rapid mineralization of organic carbon and secondary metabolites . This was illustrated in this study with...and water. The list is far from complete. Many denitrifying species, such as those from the genera Moraxella and Achromobacter , are commonly found in

Integration of oxygen signaling at the consensus HRE.

PubMed

Wenger, Roland H; Stiehl, Daniel P; Camenisch, Gieri

2005-10-18

The hypoxia-inducible factor 1 (HIF-1) was initially identified as a transcription factor that regulated erythropoietin gene expression in response to a decrease in oxygen availability in kidney tissue. Subsequently, a family of oxygen-dependent protein hydroxylases was found to regulate the abundance and activity of three oxygen-sensitive HIFalpha subunits, which, as part of the HIF heterodimer, regulated the transcription of at least 70 different effector genes. In addition to responding to a decrease in tissue oxygenation, HIF is proactively induced, even under normoxic conditions, in response to stimuli that lead to cell growth, ultimately leading to higher oxygen consumption. The growing cell thus profits from an anticipatory increase in HIF-dependent target gene expression. Growth stimuli-activated signaling pathways that influence the abundance and activity of HIFs include pathways in which kinases are activated and pathways in which reactive oxygen species are liberated. These pathways signal to the HIF protein hydroxylases, as well as to HIF itself, by means of covalent or redox modifications and protein-protein interactions. The final point of integration of all of these pathways is the hypoxia-response element (HRE) of effector genes. Here, we provide comprehensive compilations of the known growth stimuli that promote increases in HIF abundance, of protein-protein interactions involving HIF, and of the known HIF effector genes. The consensus HRE derived from a comparison of the HREs of these HIF effectors will be useful for identification of novel HIF target genes, design of oxygen-regulated gene therapy, and prediction of effects of future drugs targeting the HIF system.

Atomic Oxygen Durability Evaluation of a UV Curable Ceramer Protective Coating

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Karniotis, Christina A.; Dworak, David; Soucek, Mark

2004-01-01

The exposure of most silicones to atomic oxygen in low Earth orbit (LEO) results in the oxidative loss of methyl groups with a gradual conversion to oxides of silicon. Typically there is surface shrinkage of oxidized silicone protective coatings which leads to cracking of the partially oxidized brittle surface. Such cracks widen and branch crack with continued atomic oxygen exposure ultimately allowing atomic oxygen to reach any hydrocarbon polymers under the silicone coating. A need exists for a paintable silicone coating that is free from such surface cracking and can be effectively used for protection of polymers and composites in LEO. A new type of silicone based protective coating holding such potential was evaluated for atomic oxygen durability in an RF atomic oxygen plasma exposure facility. The coating consisted of a UV curable inorganic/organic hybrid coating, known as a ceramer, which was fabricated using a methyl substituted polysiloxane binder and nanophase silicon-oxo-clusters derived from sol-gel precursors. The polysiloxane was functionalized with a cycloaliphatic epoxide in order to be cured at ambient temperature via a cationic UV induced curing mechanism. Alkoxy silane groups were also grafted onto the polysiloxane chain, through hydrosilation, in order to form a network with the incorporated silicon-oxo-clusters. The prepared polymer was characterized by H-1 and Si-29 NMR, FT-IR, and electrospray ionization mass spectroscopy. The paper will present the results of atomic oxygen protection ability of thin ceramer coatings on Kapton H as evaluated over a range of atomic oxygen fluence levels.

Developmental control of hypoxia during bud burst in grapevine.

PubMed

Meitha, Karlia; Agudelo-Romero, Patricia; Signorelli, Santiago; Gibbs, Daniel J; Considine, John A; Foyer, Christine H; Considine, Michael J

2018-05-01

Dormant or quiescent buds of woody perennials are often dense and in the case of grapevine (Vitis vinifera L.) have a low tissue oxygen status. The precise timing of the decision to resume growth is difficult to predict, but once committed, the increase in tissue oxygen status is rapid and developmentally regulated. Here, we show that more than a third of the grapevine homologues of widely conserved hypoxia-responsive genes and nearly a fifth of all grapevine genes possessing a plant hypoxia-responsive promoter element were differentially regulated during bud burst, in apparent harmony with resumption of meristem identity and cell-cycle gene regulation. We then investigated the molecular and biochemical properties of the grapevine ERF-VII homologues, which in other species are oxygen labile and function in transcriptional regulation of hypoxia-responsive genes. Each of the 3 VvERF-VIIs were substrates for oxygen-dependent proteolysis in vitro, as a function of the N-terminal cysteine. Collectively, these data support an important developmental function of oxygen-dependent signalling in determining the timing and effective coordination bud burst in grapevine. In addition, novel regulators, including GASA-, TCP-, MYB3R-, PLT-, and WUS-like transcription factors, were identified as hallmarks of the orderly and functional resumption of growth following quiescence in buds. © 2018 John Wiley & Sons Ltd.

Evolutionary significance of osmoregulatory mechanisms in cyanobacteria

NASA Technical Reports Server (NTRS)

Yopp, J. H.; Pavlicek, J. H.; Sibley, M. H.

1986-01-01

Physiological processes of all life forms on this planet are intrinsically related to their intracellular water potential. The overall goal was the elucidation of the mechanism(s) whereby the first oxygenic phtoautotrophs (the cyanobacteria) adjust their water potential to that of a changing external water potential (that is, osmoregulate). Osmoregulation is achieved by intracellular adjustment of inorganic and/or organic solutes (osmolytes) involving specific biochemical mechanisms. Structural and biochemical evolution within the cyanobacteria is believed completed (and fixed in present day forms) by the end of the Precambrain eon. Therefore, research using cyanobacteria of all three structural types (unicellular, filamentous, and branched), each grown in the photoautotrophic (PA), photoheterotrophic (PG), and chemotrophic (CH) modes of nutrition, should provide insight into the origin and evolution of the photosynthetically related osmoregulatory mechanisms of eukaryotic organisms. The chloroplasts of these organisms are phylogenetically related to the cyanobacteria.

Propellant Feed System Leak Detection: Lessons Learned From the Linear Aerospike SR-71 Experiment (LASRE)

NASA Technical Reports Server (NTRS)

Hass, Neal; Mizukami, Masashi; Neal, Bradford A.; St. John, Clinton; Beil, Robert J.; Griffin, Timothy P.

1999-01-01

This paper presents pertinent results and assessment of propellant feed system leak detection as applied to the Linear Aerospike SR-71 Experiment (LASRE) program flown at the NASA Dryden Flight Research Center, Edwards, California. The LASRE was a flight test of an aerospike rocket engine using liquid oxygen and high-pressure gaseous hydrogen as propellants. The flight safety of the crew and the experiment demanded proven technologies and techniques that could detect leaks and assess the integrity of hazardous propellant feed systems. Point source detection and systematic detection were used. Point source detection was adequate for catching gross leakage from components of the propellant feed systems, but insufficient for clearing LASRE to levels of acceptability. Systematic detection, which used high-resolution instrumentation to evaluate the health of the system within a closed volume, provided a better means for assessing leak hazards. Oxygen sensors detected a leak rate of approximately 0.04 cubic inches per second of liquid oxygen. Pressure sensor data revealed speculated cryogenic boiloff through the fittings of the oxygen system, but location of the source(s) was indeterminable. Ultimately, LASRE was cancelled because leak detection techniques were unable to verify that oxygen levels could be maintained below flammability limits.

S-nitrosylation of GAD65 is implicated in decreased GAD activity and oxygen-induced seizures.

PubMed

Gasier, Heath G; Demchenko, Ivan T; Tatro, Lynn G; Piantadosi, Claude A

2017-07-13

Breathing oxygen at partial pressures ≥2.5 atmospheres absolute, which can occur in diving and hyperbaric oxygen (HBO 2 ) therapy, can rapidly become toxic to the central nervous system (CNS). This neurotoxicity culminates in generalized EEG epileptiform discharges, tonic-clonic convulsions and ultimately death. Increased production of neuronal nitric oxide (NO) has been implicated in eliciting hyperoxic seizures by altering the equilibrium between glutamatergic and GABAergic synaptic transmission. Inhibition of glutamic acid decarboxylase (GAD) activity in HBO 2 promotes this imbalance; however, the mechanisms by which this occurs is unknown. Therefore, we conducted a series of experiments using mice, a species that is highly susceptible to CNS oxygen toxicity, to explore the possibility that NO modulates GABA metabolism. Mice were exposed to 100% oxygen at 4 ATA for various durations, and brain GAD and GABA transaminase (GABA-T) activity, as well as S-nitrosylation of GAD65 and GAD67 were determined. HBO 2 inhibited GAD activity by 50% and this was negatively correlated with S-nitrosylation of GAD65, whereas GABA-T activity and S-nitrosylation of GAD67 were unaltered. These results suggest a new mechanism by which NO alters GABA metabolism, leading to neuroexcitation and seizures in HBO 2 . Published by Elsevier B.V.

Evolutionary ecology during the rise of dioxygen in the Earth's atmosphere.

PubMed

Sleep, Norman H; Bird, Dennis K

2008-08-27

Pre-photosynthetic niches were meagre with a productivity of much less than 10(-4) of modern photosynthesis. Serpentinization, arc volcanism and ridge-axis volcanism reliably provided H(2). Methanogens and acetogens reacted CO(2) with H(2) to obtain energy and make organic matter. These skills pre-adapted a bacterium for anoxygenic photosynthesis, probably starting with H(2) in lieu of an oxygen 'acceptor'. Use of ferrous iron and sulphide followed as abundant oxygen acceptors, allowing productivity to approach modern levels. The 'photobacterium' proliferated rooting much of the bacterial tree. Land photosynthetic microbes faced a dearth of oxygen acceptors and nutrients. A consortium of photosynthetic and soil bacteria aided weathering and access to ferrous iron. Biologically enhanced weathering led to the formation of shales and, ultimately, to granitic rocks. Already oxidized iron-poor sedimentary rocks and low-iron granites provided scant oxygen acceptors, as did freshwater in their drainages. Cyanobacteria evolved dioxygen production that relieved them of these vicissitudes. They did not immediately dominate the planet. Eventually, anoxygenic and oxygenic photosynthesis oxidized much of the Earth's crust and supplied sulphate to the ocean. Anoxygenic photosynthesis remained important until there was enough O(2) in downwelling seawater to quantitatively oxidize massive sulphides at mid-ocean ridge axes.

Two distinct arsenite-resistant variants of Leishmania amazonensis take different routes to achieve resistance as revealed by comparative transcriptomics.

PubMed

Lin, Yi-Chun; Hsu, Ju-Yu; Shu, Jui-Hsu; Chi, Yi; Chiang, Su-Chi; Lee, Sho Tone

2008-11-01

Genome-wide search for the genes involved in arsenite resistance in two distinct variants A and A' of Leishmania amazonensis revealed that the two variants used two different mechanisms to achieve resistance, even though these two variants were derived from the same clone and selected against arsenite under the same conditions. In variant A, the variant with DNA amplification, the biochemical pathways for detoxification of oxidative stress, the energy generation system to support the biochemical and physiological needs of the variant for DNA and protein synthesis and the arsenite translocating system to dispose arsenite are among the primary biochemical events that are upregulated under the arsenite stress to gain resistance. In variant A', the variant without DNA amplification, the upregulation of aquaglyceroporin (AQP) gene and the high level of resistance to arsenate point to the direction that the resistance gained by the variant is due to arsenate which is probably oxidized from arsenite in the arsenite solution used for selection and the maintenance of the cell culture. As a result of the AQP upregulation for arsenite disposal, a different set of biochemical pathways for detoxification of oxidative stress, energy generation and cellular signaling are upregulated to sustain the growth of the variant to gain resistance to arsenate. From current evidences, reactive oxygen species (ROS) overproduced by the parasite soon after exposure to arsenite appear to play an instrumental role in both variants to initiate the subsequent biochemical events that allow the same clone of L. amazonensis to take two totally different routes to diverge into two different variants.

Effects of carprofen on renal function and results of serum biochemical and hematologic analyses in anesthetized dogs that had low blood pressure during anesthesia.

PubMed

Boström, Ingrid M; Nyman, Görel C; Lord, Peter E; Häggström, Jens; Jones, Bernt E V; Bohlin, Henrik P

2002-05-01

To investigate effects of IV administered carprofen on indices of renal function and results of serum biochemical and hematologic analyses in dogs anesthetized with acepromazine-thiopentone-isoflurane that had low blood pressure during anesthesia. 6 healthy Beagles. A randomized crossover study was conducted, using the following treatments: saline (0.9% NaCl solution)-saline, saline-carprofen, and carprofen-saline. Saline (0.08 ml/kg) and carprofen (4 mg/kg) were administered IV. The first treatment was administered 30 minutes before induction of anesthesia and immediately before administration of acepromazine (0.1 mg/kg, IM). Anesthesia was induced with thiopentone (25 mg/ml, IV) and maintained with inspired isoflurane (2% in oxygen). The second treatment was administered 30 minutes after onset of inhalation anesthesia. Blood gases, circulation, and ventilation were monitored. Renal function was assessed by glomerular filtration rate (GFR), using scintigraphy, serum biochemical analyses, and urinalysis. Hematologic analysis was performed. Statistical analysis was conducted, using ANOVA or Friedman ANOVA. Values did not differ significantly among the 3 treatments. For all treatments, sedation and anesthesia caused changes in results of serum biochemical and hematologic analyses, a decrease in mean arterial blood pressure to 65 mm Hg, an increase of 115 pmol/L in angiotensin II concentration, and an increase of 100 seconds in time required to reach maximum activity counts during scintigraphy. Carprofen administered IV before or during anesthesia did not cause detectable significant adverse effects on renal function or results of serum biochemical and hematologic analyses in healthy Beagles with low blood pressure during anesthesia.

Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste.

PubMed

Dubber, Donata; Gray, Nicholas F

2010-10-01

Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modeling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD=49.2+3.00*TOC) and BOD5 (BOD5=23.7+1.68*TOC) in influent wastewaters but only for COD (COD=7.25+2.99*TOC) in final effluents.

Phytoremediation Potential of Duckweed (Lemna minor L.) On Steel Wastewater.

PubMed

Saha, Priyanka; Banerjee, Angela; Sarkar, Supriya

2015-01-01

An eco-friendly and cost effective technique- phytoremediation was used to remediate contaminants from waste water. This study demonstrated that phytoremediation ability of duckweed (Lemna minor L.) to remove chloride, sulphate from Biological Oxygen Treatment (BOT) waste water of coke oven plant. The BOT water quality was assessed by analyzing physico-biochemical characters--pH, Biological oxygen demand (BOD), Chemical oxygen demand (COD), total dissolved solids (TDS) and elemental concentration. It was observed that an increase in pH value indicated an improvement of water quality. The experimental results showed that, duckweed effectively removed 30% chloride, 16% sulphate and 14% TDS from BOT waste water, which suggested its ability in phytoremediation for removal of chloride and sulphate from BOT waste water. A maximum increase of 30% relative growth rate of duckweed was achieved after 21 days of experiment. Thus, it was concluded that duckweed, an aquatic plant, can be considered for treatment of the effluent discharged from the coke oven plant.

Monitoring and evaluation of the water quality of Budeasa Reservoir-Arges River, Romania.

PubMed

Ion, Antoanela; Vladescu, Luminita; Badea, Irinel Adriana; Comanescu, Laura

2016-09-01

The purpose of this study was to monitor and record the specific characteristics and properties of the Arges River water in the Budeasa Reservoir (the principal water resources of municipal tap water of the big Romanian city Pitesti and surrounding area) for a period of 5 years (2005-2009). The monitored physical and chemical parameters were turbidity, pH, electrical conductivity, chemical oxygen demand, 5 days biochemical oxygen demand, free dissolved oxygen, nitrite, nitrate, ammonia nitrogen, chloride, total dissolved iron ions, sulfate, manganese, phosphate, total alkalinity, and total hardness. The results were discussed in correlation with the precipitation values during the study. Monthly and annual values of each parameter determined in the period January 2005-December 2009 were used as a basis for the classification of Budeasa Reservoir water, according to the European legislation, as well as for assessing its quality as a drinking water supply. Principal component analysis and Pearson correlation coefficients were used as statistical procedures in order to evaluate the data obtained during this study.

Biological modulation of planetary atmospheres: The early Earth scenario

NASA Technical Reports Server (NTRS)

Schidlowski, M.

1985-01-01

The establishment and subsequent evolution of life on Earth had a profound impact on the chemical regime at the planet's surface and its atmosphere. A thermodynamic gradient was imposed on near-surface environments that served as the driving force for a number on important geochemical transformations. An example is the redox imbalance between the modern atmosphere and the material of the Earth's crust. Current photochemical models predict extremely low partial pressures of oxygen in the Earth's prebiological atmosphere. There is widespread consensus that any large-scale oxygenation of the primitive atmosphere was contingent on the advent of biological (autotrophic) carbon fixation. It is suggested that photoautotrophy existed both as a biochemical process and as a geochemical agent since at least 3.8 Ga ago. Combining the stoichiometry of the photosynthesis reaction with a carbon isotope mass balance and current concepts for the evolution of the stationary sedimentary mass as a funion of time, it is possible to quantify, the accumulation of oxygen and its photosynthetic oxidation equivalents through Earth history.

An integrated optical oxygen sensor fabricated using rapid-prototyping techniques.

PubMed

Chang-Yen, David A; Gale, Bruce K

2003-11-01

This paper details the design and fabrication of an integrated optical biochemical sensor using a select oxygen-sensitive fluorescent dye, tris(2,2'-bipyridyl) dichlororuthenium(ii) hexahydrate, combined with polymeric waveguides that are fabricated on a glass substrate. The sensor uses evanescent interaction of light confined within the waveguide with the dye that is immobilized on an SU-8 waveguide surface. Adhesion of the dye to the integrated waveguide surface is accomplished using a unique process of spin-coating/electrostatic layer-by-layer formation. The SU-8 waveguide was chemically modified to allow the deposition process. Exposure of the dye molecules to the analyte and subsequent chemical interaction is achieved by directly coupling the fluid channel to the integrated waveguide. The completed sensor was linear in the dissolved oxygen across a wide range of interest and had a sensitivity of 0.6 ppm. A unique fabrication aspect of this sensor is the inherent simplicity of the design, and the resulting rapidity of fabrication, while maintaining a high degree of functionality and flexibility.

Augmented reality experimentation on oxygen gas generation from hydrogen peroxide and bleach reaction.

PubMed

Gan, Hong Seng; Tee, Nicholas Yee Kwang; Bin Mamtaz, Mohammad Raziun; Xiao, Kevin; Cheong, Brandon Huey-Ping; Liew, Oi Wah; Ng, Tuck Wah

2018-05-01

The appreciation and understanding of gas generation through processes is vital in biochemical education. In this work, an augmented reality tool is reported to depict the redox reaction between hydrogen peroxide and sodium hypochlorite solutions, two ubiquitous oxidizing agents, to create oxygen, a combustible gas. As it operates out of smartphones or tablets, students are able to conduct the exercise collaboratively, respond in a manner similar to an actual physical experiment, and able to depict the oxygen volume changes in relation to the volume of hydrogen peroxide of different concentrations used. The tool offers to help students acquire bench skills by limiting handing risks and to mitigate possible student anxiety on handling chemical materials and implements in the laboratory. The feedback received from Year 11 and 12 high school student participants in an outreach exercise indicate the overall effectiveness of this tool. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):245-252, 2018. © 2018 The International Union of Biochemistry and Molecular Biology.

Cocaine-induced neuroadaptations in glutamate transmission

PubMed Central

Schmidt, Heath D.; Pierce, R. Christopher

2017-01-01

A growing body of evidence indicates that repeated exposure to cocaine leads to profound changes in glutamate transmission in limbic nuclei, particularly the nucleus accumbens. This review focuses on preclinical studies of cocaine-induced behavioral plasticity, including behavioral sensitization, self-administration, and the reinstatement of cocaine seeking. Behavioral, pharmacological, neurochemical, electrophysiological, biochemical, and molecular biological changes associated with cocaine-induced plasticity in glutamate systems are reviewed. The ultimate goal of these lines of research is to identify novel targets for the development of therapies for cocaine craving and addiction. Therefore, we also outline the progress and prospects of glutamate modulators for the treatment of cocaine addiction. PMID:20201846

Drone inflight mixing of biochemical samples.

PubMed

Katariya, Mayur; Chung, Dwayne Chung Kim; Minife, Tristan; Gupta, Harshit; Zahidi, Alifa Afiah Ahmad; Liew, Oi Wah; Ng, Tuck Wah

2018-03-15

Autonomous systems for sample transport to the laboratory for analysis can be improved in terms of timeliness, cost and error mitigation in the pre-analytical testing phase. Drones have been reported for outdoor sample transport but incorporating devices on them to attain homogenous mixing of reagents during flight to enhance sample processing timeliness is limited by payload issues. It is shown here that flipping maneuvers conducted with quadcopters are able to facilitate complete and gentle mixing. This capability incorporated during automated sample transport serves to address an important factor contributing to pre-analytical variability which ultimately impacts on test result reliability. Copyright © 2018 Elsevier Inc. All rights reserved.

Structure and specificity of FEN-1 from Methanopyrus kandleri

DOE PAGES

Shah, Santosh; Dunten, Pete; Stiteler, Amanda; ...

2014-11-18

DNA repair is fundamental to genome stability and is found in all three domains of life. However, many archaeal species, such as Methanopyrus kandleri, contain only a subset of the eukaryotic nucleotide excision repair (NER) homologues, and those present often contain significant differences compared to their eukaryotic homologues. To clarify the role of the NER XPG-like protein Mk0566 from M. kandleri, its biochemical activity and three dimensional structure were investigated. Ultimately, we found both to be more similar to human FEN-1 than human XPG, suggesting a biological role in replication and long-patch base excision repair rather than in NER.

The adsorption and dissociation of oxygen on Ag (111) supported χ3 borophene

NASA Astrophysics Data System (ADS)

Luo, W. W.; Liu, G.; Wang, X.; Lei, X. L.; Ouyang, C. Y.; Liu, S. Q.

2018-05-01

The superstructure of χ3 borophene on Ag (111) has recently been synthesized in experiment. In this work, we investigate its structural, electronic properties and the oxidation mechanism through first-principles calculations. We find the superstructure of χ3 borophene on Ag (111) maintain the planar characteristics, like its free-standing form, owing to the weakly interaction between adsorbate and substrate. Moreover, oxygen molecule can be spontaneously adsorbed on its superstructure in a manner of chemical adsorption. Importantly, the energy barrier of ∼0.35 eV for oxygen dissociation indicates its relative stability in ambient conditions compared with the active silicene. Furthermore, the mobility of O2-dissociation-induced O atom is poor at room temperature, implying the difficult migration of O atom on borophene surface. On the other hand, due to the strong Bsbnd O bonding, desorption of O2-dissociation-induced O atoms on superstructure of χ3 borophene becomes impossible, ultimately leading to form the boron oxides.

Chemical strain engineering of magnetism in PrVO3 thin films

NASA Astrophysics Data System (ADS)

Prellier, Wilfrid; Copie, Olivier; Varignon, Julien; Rotella, Helene; Steciuk, Gwladys; Boullay, Philippe; Pautrat, Alain; David, Adrian; Mercey, Bernard; Ghosez, Philippe

Transition metal oxides having a perovskite structure present a wide range of functional properties ranging from insulator-to-metal, ferroelectricity, colossal magnetoresistance, high-temperature superconductivity and multiferroicity. Such systems are generally characterized by strong electronic correlations, complex phase diagrams and competing ground states. In addition, small perturbation induced by external stimuli (electric or magnetic field, temperature, strain, pressure..) may change structure, and ultimately modify the physical properties. Here, we synthetize an orthorhombic perovskite praseodymium vanadate (PrVO3), which is grown on strontium titanate substrate. We show that the control of the content of oxygen vacancies, the so-called chemical strain, can indeed result in unexpected properties. We further demonstrate that the Néel temperature can be tuned using the same substrate in agreement with first-principles calculations, and demonstrate that monitoring the concentration of oxygen vacancies through the oxygen partial pressure or the growth temperature can produce a substantial macroscopic tensile strain of a few percents.

Temporal and Spatial Variability of the Martian Hot Oxygen Corona

NASA Astrophysics Data System (ADS)

Deighan, J.; Jain, S.; Chaffin, M.; Chaufray, J. Y.; Schneider, N. M.; Clarke, J. T.; Mayyasi, M.; Lillis, R. J.; Eparvier, F. G.; Thiemann, E.; Chamberlin, P. C.

2017-12-01

The dominant loss mechanism of oxygen from Mars to space in the current epoch is thought to be photochemical escape of hot oxygen produced by dissociative recombination of O2+. This ion is ultimately sourced from CO2+, which is the primary product of photoionization. The escaping hot oxygen population is accompanied by a gravitationally bound hot oxygen corona produced by the same mechanism. The MAVEN spacecraft has been at Mars since November 2014, with multiple seasons suitable for the IUVS instrument to observe the dayside hot oxygen corona via fluorescence of the O I 130.4 nm triplet. This provides the opportunity to examine temporal variations associated with changes in the photoionizing solar EUV radiation which produces CO2+ and O2+ ions. We present results based on two seasons: LS = 270 in Mars Year 32 during the maximum of Solar Cycle 24 and LS = 210 in Mars Year 33 late in the declining phase of the same Solar Cycle. The data in both seasons contain multiple solar rotations. We compare the oxygen corona density to the EUV solar flux measured by MAVEN/EUVM and ionization frequencies calculated therefrom. The peak brightness of ionospheric CO2+ UVD emission from IUVS limb scans is also used as a direct indicator of the photoionization frequency. As expected, the result is a strong correlation between solar EUV input, observed ionization frequency, and the density of the hot oxygen corona. In addition, a new observation strategy was employed during the MY 33 season to view the Martian corona near the sub-solar point with anti-parallel lines of sight from opposing hemispheres. These observations reveal a significant hemispherical asymmetry in brightness, providing a constraint on the large scale spatial variability of the dayside oxygen corona.

High-Throughput Phenotyping of Maize Leaf Physiological and Biochemical Traits Using Hyperspectral Reflectance1[OPEN

PubMed Central

Yendrek, Craig R.; Tomaz, Tiago; Montes, Christopher M.; Cao, Youyuan; Morse, Alison M.; Brown, Patrick J.; McIntyre, Lauren M.; Leakey, Andrew D.B.

2017-01-01

High-throughput, noninvasive field phenotyping has revealed genetic variation in crop morphological, developmental, and agronomic traits, but rapid measurements of the underlying physiological and biochemical traits are needed to fully understand genetic variation in plant-environment interactions. This study tested the application of leaf hyperspectral reflectance (λ = 500–2,400 nm) as a high-throughput phenotyping approach for rapid and accurate assessment of leaf photosynthetic and biochemical traits in maize (Zea mays). Leaf traits were measured with standard wet-laboratory and gas-exchange approaches alongside measurements of leaf reflectance. Partial least-squares regression was used to develop a measure of leaf chlorophyll content, nitrogen content, sucrose content, specific leaf area, maximum rate of phosphoenolpyruvate carboxylation, [CO2]-saturated rate of photosynthesis, and leaf oxygen radical absorbance capacity from leaf reflectance spectra. Partial least-squares regression models accurately predicted five out of seven traits and were more accurate than previously used simple spectral indices for leaf chlorophyll, nitrogen content, and specific leaf area. Correlations among leaf traits and statistical inferences about differences among genotypes and treatments were similar for measured and modeled data. The hyperspectral reflectance approach to phenotyping was dramatically faster than traditional measurements, enabling over 1,000 rows to be phenotyped during midday hours over just 2 to 4 d, and offers a nondestructive method to accurately assess physiological and biochemical trait responses to environmental stress. PMID:28049858

Biophysical stimulation for in vitro engineering of functional cardiac tissues.

PubMed

Korolj, Anastasia; Wang, Erika Yan; Civitarese, Robert A; Radisic, Milica

2017-07-01

Engineering functional cardiac tissues remains an ongoing significant challenge due to the complexity of the native environment. However, our growing understanding of key parameters of the in vivo cardiac microenvironment and our ability to replicate those parameters in vitro are resulting in the development of increasingly sophisticated models of engineered cardiac tissues (ECT). This review examines some of the most relevant parameters that may be applied in culture leading to higher fidelity cardiac tissue models. These include the biochemical composition of culture media and cardiac lineage specification, co-culture conditions, electrical and mechanical stimulation, and the application of hydrogels, various biomaterials, and scaffolds. The review will also summarize some of the recent functional human tissue models that have been developed for in vivo and in vitro applications. Ultimately, the creation of sophisticated ECT that replicate native structure and function will be instrumental in advancing cell-based therapeutics and in providing advanced models for drug discovery and testing. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Ultrastructural changes during spermatogenesis, biochemical and hormonal evidences of testicular toxicity caused by TBT in freshwater prawn Macrobrachium rosenbergii (De Man, 1879).

PubMed

Revathi, Peranandam; Iyapparaj, Palanisamy; Vasanthi, Lourduraj Arockia; Munuswamy, Natesan; Krishnan, Muthukalingan

2014-10-01

The present investigation documents the impact of tributyltin (TBT) on the ultrastructural variation of spermatogenesis in freshwater prawn Macrobrachium rosenbergii. The environmentally realistic concentration of TBT can cause damages to the endocrine and reproductive physiology of crustaceans. In this context, three concentrations viz. 10, 100, and 1000 ng/L were selected and exposed to prawns for 90 days. The TBT exposed prawn exhibited decrease the reproductive activity as evidenced by sperm count and sperm length compared to control. Histopathological results revealed the retarded testicular development, abnormal structure of seminiferous tubule, decrease in the concentration of spermatozoa, diminution of seminiferous tubule membrane, abundance of spermatocytes and vacuolation in testis of treated prawns. Ultrastructural study also confirmed the impairment of spermatogenesis in treated prawns. Furthermore, radioimmunoassay (RIA) clearly documented the reduction of testosterone level in TBT exposed groups. Thus, TBT substantially reduced the level of male sex hormone as well as biochemical constituents which ultimately led to impairment of spermatogenesis in the freshwater male prawn M. rosenbergii. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

Biochemical identification of residues that discriminate between 3,4-dihydroxyphenylalanine decarboxylase and 3,4-dihydroxyphenylacetaldehyde synthase-mediated reactions.

PubMed

Liang, Jing; Han, Qian; Ding, Haizhen; Li, Jianyong

2017-12-01

In available insect genomes, there are several L-3,4-dihydroxyphenylalanine (L-dopa) decarboxylase (DDC)-like or aromatic amino acid decarboxylase (AAAD) sequences. This contrasts to those of mammals whose genomes contain only one DDC. Our previous experiments established that two DDC-like proteins from Drosophila actually mediate a complicated decarboxylation-oxidative deamination process of dopa in the presence of oxygen, leading to the formation of 3,4-dihydroxyphenylacetaldehyde (DHPA), CO 2 , NH 3, and H 2 O 2 . This contrasts to the typical DDC-catalyzed reaction, which produces CO 2 and dopamine. These DDC-like proteins were arbitrarily named DHPA synthases based on their critical role in insect soft cuticle formation. Establishment of reactions catalyzed by these AAAD-like proteins solved a puzzle that perplexed researchers for years, but to tell a true DHPA synthase from a DDC in the insect AAAD family remains problematic due to high sequence similarity. In this study, we performed extensive structural and biochemical comparisons between DHPA synthase and DDC. These comparisons identified several target residues potentially dictating DDC-catalyzed and DHPA synthase-catalyzed reactions, respectively. Comparison of DHPA synthase homology models with crystal structures of typical DDC proteins, particularly residues in the active sites, provided further insights for the roles these identified target residues play. Subsequent site-directed mutagenesis of the tentative target residues and activity evaluations of their corresponding mutants determined that active site His192 and Asn192 are essential signature residues for DDC- and DHPA synthase-catalyzed reactions, respectively. Oxygen is required in DHPA synthase-mediated process and this oxidizing agent is reduced to H 2 O 2 in the process. Biochemical assessment established that H 2 O 2 , formed in DHPA synthase-mediated process, can be reused as oxidizing agent and this active oxygen species is reduced to H 2 O; thereby avoiding oxidative stress by H 2 O 2 . Results of our structural and functional analyses provide a reasonable explanation of mechanisms involved in DHPA synthase-mediated reactions. Based on the key active site residue Asn192, identified in Drosophila DHPA synthase, we were able to distinguish all available insect DHPA synthases from DDC sequences primarily. Copyright © 2017. Published by Elsevier Ltd.

Effects of land use on water quality and transport of selected constituents in streams in Mecklenburg County, North Carolina, 1994–98

USGS Publications Warehouse

Ferrell, Gloria M.

2001-01-01

Transport rates for total solids, total nitrogen, total phosphorus, biochemical oxygen demand, chromium, copper, lead, nickel, and zinc during 1994–98 were computed for six stormwater-monitoring sites in Mecklenburg County, North Carolina. These six stormwater-monitoring sites were operated by the Mecklenburg County Department of Environmental Protection, in cooperation with the City of Charlotte, and are located near the mouths of major streams. Constituent transport at the six study sites generally was dominated by nonpoint sources, except for nitrogen and phosphorus at two sites located downstream from the outfalls of major municipal wastewater-treatment plants.To relate land use to constituent transport, regression equations to predict constituent yield were developed by using water-quality data from a previous study of nine stormwater-monitoring sites on small streams in Mecklenburg County. The drainage basins of these nine stormwater sites have relatively homogeneous land-use characteristics compared to the six study sites. Mean annual construction activity, based on building permit files, was estimated for all stormwater-monitoring sites and included as an explanatory variable in the regression equations. These regression equations were used to predict constituent yield for the six study sites. Predicted yields generally were in agreement with computed yields. In addition, yields were predicted by using regression equations derived from a national urban water-quality database. Yields predicted from the regional regression equations generally were about an order of magnitude lower than computed yields.Regression analysis indicated that construction activity was a major contributor to transport of the constituents evaluated in this study except for total nitrogen and biochemical oxygen demand. Transport of total nitrogen and biochemical oxygen demand was dominated by point-source contributions. The two study basins that had the largest amounts of construction activity also had the highest total solids yields (1,300 and 1,500 tons per square mile per year). The highest total phosphorus yields (3.2 and 1.7 tons per square mile per year) attributable to nonpoint sources also occurred in these basins. Concentrations of chromium, copper, lead, nickel, and zinc were positively correlated with total solids concentrations at most of the study sites (Pearson product-moment correlation >0.50). The site having the highest median concentrations of chromium, copper, and nickel also was the site having the highest computed yield for total solids.

Gene cloning and in vivo characterization of a dibenzothiophene dioxygenase from Xanthobacter polyaromaticivorans.

PubMed

Hirano, Shin-Ichi; Haruki, Mitsuru; Takano, Kazufumi; Imanaka, Tadayuki; Morikawa, Masaaki; Kanaya, Shigenori

2006-02-01

Xanthobacter polyaromaticivorans sp. nov. 127W is a bacterial strain that is capable of degrading a wide range of cyclic aromatic compounds such as dibenzothiophene, biphenyl, naphthalene, anthracene, and phenanthrene even under extremely low oxygen [dissolved oxygen (DO)< or = 0.2 ppm] conditions (Hirano et al., Biosci Biotechnol Biochem 68:557-564, 2004). A major protein fraction carrying dibenzothiophene degradation activity was purified. Based on its partial amino acid sequences, dbdCa gene encoding alpha subunit terminal oxygenase (DbdCa) and its flanking region were cloned and sequenced. A phylogenetic analysis based on the amino acid sequence demonstrates that DbdCa is a member of a terminal oxygenase component of group IV ring-hydroxylating dioxygenases for biphenyls and monocyclic aromatic hydrocarbons, rather than group III dioxygenases for polycyclic aromatic hydrocarbons. Gene disruption in dbdCa abolished almost of the degradation activity against biphenyl, dibenzothiophene, and anthracene. The gene disruption also impaired degradation activity of the strain under extremely low oxygen conditions (DO< or = 0.2 ppm). These results indicate that Dbd from 127W represents a group IV dioxygenase that is functional even under extremely low oxygen conditions.

NIR spectroscopic investigation of m. vastus lateralis in patients with mitochondrial myopathies as detected by respirometric investigation of mitochondrial function in skinned fibers

NASA Astrophysics Data System (ADS)

Gellerich, Frank N.; Mueller, Tobias; Nioka, Shoko; Hertel, Katrin; Schulte-Mattler, Wilhelm J.; Zierz, Stephan; Chance, Britton

1998-01-01

Noninvasive measurement of changes in oxygenation of human skeletal muscle can be done with a dual-wavelength near infrared (NIR) spectrophotometer. This allows a noninvasive investigation of muscle mitochondria. An exercise protocol was developed to study the load dependent changes in oxygenation of m. vastus lateralis of myopathic patients. On a bicycle ergometer exercise was done periodically. One period consisted of 1.5 min exercise followed by 3 min rest. Work load in the first period was 20 W, and was increased by 10 W for each subsequent period until maximal work load was reached. In 12 healthy volunteers we observed oxygenation of muscle during periods of low work load (warm-up effect). During periods of high work load the muscle deoxygenated. The work load at transition from oxygenation to deoxygenation (deoxygenation threshold) in controls was 75 W. In 3 patients with myopathies, in addition to NIR- spectroscopy, function of mitochondria of specimen of m. vastus lateralis was investigated biochemically. Muscle fibers were skinned with saponin and investigated with high resolution respirometry and multiple substrate-inhibitor- titration. Mitochondrial function was impaired in patients who had abnormal findings in NIR spectroscopy.

NIR spectroscopic investigation of m. vastus lateralis in patients with mitochondrial myopathies as detected by respirometric investigation of mitochondrial function in skinned fibers

NASA Astrophysics Data System (ADS)

Gellerich, Frank N.; Mueller, Tobias; Nioka, Shoko; Hertel, Katrin; Schulte-Mattler, Wilhelm J.; Zierz, Stephan; Chance, Britton

1997-12-01

Noninvasive measurement of changes in oxygenation of human skeletal muscle can be done with a dual-wavelength near infrared (NIR) spectrophotometer. This allows a noninvasive investigation of muscle mitochondria. An exercise protocol was developed to study the load dependent changes in oxygenation of m. vastus lateralis of myopathic patients. On a bicycle ergometer exercise was done periodically. One period consisted of 1.5 min exercise followed by 3 min rest. Work load in the first period was 20 W, and was increased by 10 W for each subsequent period until maximal work load was reached. In 12 healthy volunteers we observed oxygenation of muscle during periods of low work load (warm-up effect). During periods of high work load the muscle deoxygenated. The work load at transition from oxygenation to deoxygenation (deoxygenation threshold) in controls was 75 W. In 3 patients with myopathies, in addition to NIR- spectroscopy, function of mitochondria of specimen of m. vastus lateralis was investigated biochemically. Muscle fibers were skinned with saponin and investigated with high resolution respirometry and multiple substrate-inhibitor- titration. Mitochondrial function was impaired in patients who had abnormal findings in NIR spectroscopy.

Effect of hemodialysis on factors influencing oxygen transport.

PubMed

Hirszel, P; Maher, J F; Tempel, G E; Mengel, C E

1975-06-01

Ten patients underwent 4 study hemodialyses, one with standard dialysis conditions, one with an isophosphate dialysate, one with simultaneous ammonium chloride loading, and other, after pretreatment, with sodium bicarbonate. Measurement of hemoglobin oxygen affinity (P-50), erythrocyte 2,3-DPG, blood-gasses, and serum chemistries revealed biochemically effective hemodialyses and slight changes in oxygen transport parameters. The P-50 (in vivo) values decreased slightly but significantly (p greater than 0.05) with dialysis. When corrected to pH 7.4, eliminating the Bohr effect, P-50 increased (p greater than 0.05). With unmodified dialysis elevated values of 2,3-DPG (in comparison to normal) decreased, a change that did not correlate with delta-p-50, delta-serum phosphate, or delta-serum creatinine. With standard and isophosphate dialyses Po-2 decreased significantly. The decrease correlated with delta-hydrogen ion concentration and did not occur with dialyses designed to maintain pH constant. Thus, hemodialysis influences many factors that affect oxygen transport in different and counterbalancing directions. These changes are not totally explained by alterations in 2,3-DPG, pH or serum phosphate. Maintenance of acidosis or hyperphosphatemia during dialysis is not recommended.

The quality of surface waters in Texas

USGS Publications Warehouse

Rawson, Jack

1974-01-01

The discharge-weighted average concentrations of dissolved solids, chloride, and ,sulfate for many of the principal streams in Texas are less than 500 mg/l (millijgraljls per liter), 250 mg/l, and 250 mg/l, respectively. At 65 of 131 sites on streams that were sampled at least 10 times, the biochemical oxygen demand of at least half the samples exceeded 3.0 mg/l. At 20 of the sites, the dissolved-oxygen content of at least half the samples was less than 5.0 mg/l. The higher concentrations of minor elements usually were detected in waters from urban areas, indicating a relation to man's activities. Small amounts of some pesticides are widely distributed in low concentrations. The higher concentrations usually were detected in waters from urban areas.

Effects of residential wastewater treatment systems on ground-water quality in west-central Jefferson County, Colorado

USGS Publications Warehouse

Hall, Dennis C.; Hillier, D.E.; Nickum, Edward; Dorrance, W.G.

1981-01-01

The use of residential wastewater-treatment systems in Evergreen Meadows, Marshdale, and Herzman Mesa, Colo., has degraded ground-water quality to some extent in each community. Age of community; average lot size; slope of land surface; composition, permeability, and thickness of surficial material; density, size , and orientation of fractures; maintenance of wastewater-treatment systems; and presence of animals are factors possibly contributing to the degradation of ground-water quality. When compared with effluent from aeration-treatment tanks, effluent fom septic-treatment tanks is characterized by greater biochemical oxygen demand and greater concentrations of detergents. When compared with effluent from septic-treatment tanks, effluent from aeration-treatment tanks is characterized by greater concentrations of dissolved oxygen, nitrite, nitrate, sulfate, and dissolved solids. (USGS)

Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from CO2 Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Muscatello, Anthony

2015-01-01

Oxygen recovery from respiratory CO2 is an important aspect of human spaceflight. Methods exist to sequester the CO2, but production of oxygen needs further development. The current ISS Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction is the only real alternative to the Sabatier reaction, but in the last reaction in the cycle (Boudouard) the resulting carbon buildup will eventually foul the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling, find a use for this waste product, and increase efficiency, we propose testing various self-cleaning catalyst designs in an existing MSFC Boudouard reaction test bed and to determine which one is the most reliable in conversion and lack of fouling. Challenges include mechanical reliability of the cleaning method and maintaining high conversion efficiency with lower catalyst surface area. The above chemical reactions are well understood, but planned implementations are novel (TRL 2) and haven't been investigated at any level.

Study on a practical robotic follower to support home oxygen therapy patients--questionnaire-based concept evaluation by the patients-.

PubMed

Endo, Gen; Iemura, Yu; Fukushima, Edwardo F; Hirose, Shigeo; Iribe, Masatsugu; Ikeda, Ryota; Onishi, Kohei; Maeda, Naoto; Takubo, Toshio; Ohira, Mineko

2013-06-01

Home oxygen therapy (HOT) is a medical treatment for the patients suffering from severe lung diseases. Although walking outdoors is recommended for the patients to maintain physical strength, the patients always have to carry a portable oxygen supplier which is not sufficiently light weight for this purpose. Our ultimate goal is to develop a mobile robot to carry an oxygen tank and follow a patient in an urban outdoor environment. We have proposed a mobile robot with a tether interface to detect the relative position of the foregoing patient. In this paper, we report the questionnaire-based evaluation about the two developed prototypes by the HOT patients. We conduct maneuvering experiments, and then obtained questionnaire-based evaluations from the 20 patients. The results show that the basic following performance is sufficient and the pulling force of the tether is sufficiently small for the patients. Moreover, the patients prefer the small-sized prototype for compactness and light weight to the middle-sized prototype which can carry larger payload. We also obtained detailed requests to improve the robots. Finally the results show the general concept of the robot is favorably received by the patients.

A unique mode of tissue oxygenation and the adaptive radiation of teleost fishes.

PubMed

Randall, D J; Rummer, J L; Wilson, J M; Wang, S; Brauner, C J

2014-04-15

Teleost fishes constitute 95% of extant aquatic vertebrates, and we suggest that this is related in part to their unique mode of tissue oxygenation. We propose the following sequence of events in the evolution of their oxygen delivery system. First, loss of plasma-accessible carbonic anhydrase (CA) in the gill and venous circulations slowed the Jacobs-Stewart cycle and the transfer of acid between the plasma and the red blood cells (RBCs). This ameliorated the effects of a generalised acidosis (associated with an increased capacity for burst swimming) on haemoglobin (Hb)-O2 binding. Because RBC pH was uncoupled from plasma pH, the importance of Hb as a buffer was reduced. The decrease in buffering was mediated by a reduction in the number of histidine residues on the Hb molecule and resulted in enhanced coupling of O2 and CO2 transfer through the RBCs. In the absence of plasma CA, nearly all plasma bicarbonate ultimately dehydrated to CO2 occurred via the RBCs, and chloride/bicarbonate exchange was the rate-limiting step in CO2 excretion. This pattern of CO2 excretion across the gills resulted in disequilibrium states for CO2 hydration/dehydration reactions and thus elevated arterial and venous plasma bicarbonate levels. Plasma-accessible CA embedded in arterial endothelia was retained, which eliminated the localized bicarbonate disequilibrium forming CO2 that then moved into the RBCs. Consequently, RBC pH decreased which, in conjunction with pH-sensitive Bohr/Root Hbs, elevated arterial oxygen tensions and thus enhanced tissue oxygenation. Counter-current arrangement of capillaries (retia) at the eye and later the swim bladder evolved along with the gas gland at the swim bladder. Both arrangements enhanced and magnified CO2 and acid production and, therefore, oxygen secretion to those specialised tissues. The evolution of β-adrenergically stimulated RBC Na(+)/H(+) exchange protected gill O2 uptake during stress and further augmented plasma disequilibrium states for CO2 hydration/dehydration. Finally, RBC organophosphates (e.g. NTP) could be reduced during hypoxia to further increase Hb-O2 affinity without compromising tissue O2 delivery because high-affinity Hbs could still adequately deliver O2 to the tissues via Bohr/Root shifts. We suggest that the evolution of this unique mode of tissue O2 transfer evolved in the Triassic/Jurassic Period, when O2 levels were low, ultimately giving rise to the most extensive adaptive radiation of extant vertebrates, the teleost fishes.

Unearthing the secrets of mitochondrial ROS and glutathione in bioenergetics.

PubMed

Mailloux, Ryan J; McBride, Skye L; Harper, Mary-Ellen

2013-12-01

During the cellular oxidation of fuels, electrons are used to power the proton pumps of the mitochondrial electron transport chain (ETC) and ultimately drive ATP synthesis and the reduction of molecular oxygen to water. During these oxidative processes, some electrons can 'spin off' during fuel oxidation and electron transport to univalently reduce O2, forming reactive oxygen species (ROS). In excess, ROS can be detrimental; however, at low concentrations oxyradicals are essential signaling molecules. Mitochondria thus use a battery of systems to finely control types and levels of ROS, including antioxidants. Several antioxidant systems depend on glutathione. Here, we review mitochondrial ROS homeostatic systems, including emerging knowledge about roles of glutathione in redox balance and the control of protein function by post-translational modification. Copyright © 2013 Elsevier Ltd. All rights reserved.

Venovenous Extracorporeal Membrane Oxygenation in an Adult Patient With Prader-Willi Syndrome: A Nutrition Case Report.

PubMed

Pelekhaty, Stacy; Menaker, Jay

2018-03-12

Prader-Willi Syndrome (PWS) is a genetic condition that results in a constellation of symptoms and typically results in hyperphagia and obesity in adulthood. Critically ill adults with PWS present a unique challenge to the nutrition professional, particularly when they require support modalities such as extracorporeal membrane oxygenation (ECMO). The purpose of this case study is to review the nutrition care of a critically ill adult patient with PWS who required venovenous ECMO. The patient was successfully managed with a hypocaloric, high-protein approach, which did not result in the diagnosis of malnutrition during his hospitalization. The patient was ultimately transitioned off extracorporeal life support and discharged to a rehabilitation facility. © 2018 American Society for Parenteral and Enteral Nutrition.

Prevalence of Helicobacter Pylori in Gastric Fluid in the Surgical Patient

DTIC Science & Technology

1998-01-01

of five percent. This percentage closely matches the oxygen level found in the stomach’s mucous layer . It has an electropositive internal milieu which...amounts of urease which cleaves urea into ammonia and carbon dioxide. The presence of urease is one of the biochemical markers used to help identify...in acidic gastric juice where small amounts of urea are present. Helicobacter pylorl produces urease which breaks down the urea and produces ammonia

Temperature Responses of C4 Photosynthesis: Biochemical Analysis of Rubisco, Phosphoenolpyruvate Carboxylase, and Carbonic Anhydrase in Setaria viridis.

PubMed

Boyd, Ryan A; Gandin, Anthony; Cousins, Asaph B

2015-11-01

The photosynthetic assimilation of CO2 in C4 plants is potentially limited by the enzymatic rates of Rubisco, phosphoenolpyruvate carboxylase (PEPc), and carbonic anhydrase (CA). Therefore, the activity and kinetic properties of these enzymes are needed to accurately parameterize C4 biochemical models of leaf CO2 exchange in response to changes in CO2 availability and temperature. There are currently no published temperature responses of both Rubisco carboxylation and oxygenation kinetics from a C4 plant, nor are there known measurements of the temperature dependency of the PEPc Michaelis-Menten constant for its substrate HCO3 (-), and there is little information on the temperature response of plant CA activity. Here, we used membrane inlet mass spectrometry to measure the temperature responses of Rubisco carboxylation and oxygenation kinetics, PEPc carboxylation kinetics, and the activity and first-order rate constant for the CA hydration reaction from 10°C to 40°C using crude leaf extracts from the C4 plant Setaria viridis. The temperature dependencies of Rubisco, PEPc, and CA kinetic parameters are provided. These findings describe a new method for the investigation of PEPc kinetics, suggest an HCO3 (-) limitation imposed by CA, and show similarities between the Rubisco temperature responses of previously measured C3 species and the C4 plant S. viridis. © 2015 American Society of Plant Biologists. All Rights Reserved.

Estimates of Nitrogen, Phosphorus, Biochemical Oxygen Demand, and Fecal Coliforms Entering the Environment Due to Inadequate Sanitation Treatment Technologies in 108 Low and Middle Income Countries.

PubMed

Fuhrmeister, Erica R; Schwab, Kellogg J; Julian, Timothy R

2015-10-06

Understanding the excretion and treatment of human waste (feces and urine) in low and middle income countries (LMICs) is necessary to design appropriate waste management strategies. However, excretion and treatment are often difficult to quantify due to decentralization of excreta management. We address this gap by developing a mechanistic, stochastic model to characterize phosphorus, nitrogen, biochemical oxygen demand (BOD), and fecal coliform pollution from human excreta for 108 LMICs. The model estimates excretion and treatment given three scenarios: (1) use of existing sanitation systems, (2) use of World Health Organization-defined "improved sanitation", and (3) use of best available technologies. Our model estimates that more than 10(9) kg/yr each of phosphorus, nitrogen and BOD are produced. Of this, 22(19-27)%, 11(7-15)%, 17(10-23)%, and 35 (23-47)% (mean and 95% range) BOD, nitrogen, phosphorus, and fecal coliforms, respectively, are removed by existing sanitation systems. Our model estimates that upgrading to "improved sanitation" increases mean removal slightly to between 17 and 53%. Under the best available technology scenario, only approximately 60-80% of pollutants are treated. To reduce impact of nutrient and microbial pollution on human and environmental health, improvements in both access to adequate sanitation and sanitation treatment efficiency are needed.

Analytical applications of microbial fuel cells. Part I: Biochemical oxygen demand.

PubMed

Abrevaya, Ximena C; Sacco, Natalia J; Bonetto, Maria C; Hilding-Ohlsson, Astrid; Cortón, Eduardo

2015-01-15

Microbial fuel cells (MFCs) are bio-electrochemical devices, where usually the anode (but sometimes the cathode, or both) contains microorganisms able to generate and sustain an electrochemical gradient which is used typically to generate electrical power. In the more studied set-up, the anode contains heterotrophic bacteria in anaerobic conditions, capable to oxidize organic molecules releasing protons and electrons, as well as other by-products. Released protons could reach the cathode (through a membrane or not) whereas electrons travel across an external circuit originating an easily measurable direct current flow. MFCs have been proposed fundamentally as electric power producing devices or more recently as hydrogen producing devices. Here we will review the still incipient development of analytical uses of MFCs or related devices or set-ups, in the light of a non-restrictive MFC definition, as promising tools to asset water quality or other measurable parameters. An introduction to biological based analytical methods, including bioassays and biosensors, as well as MFCs design and operating principles, will also be included. Besides, the use of MFCs as biochemical oxygen demand sensors (perhaps the main analytical application of MFCs) is discussed. In a companion review (Part 2), other new analytical applications are reviewed used for toxicity sensors, metabolic sensors, life detectors, and other proposed applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of multivariate linear regression and artificial neural networks in prediction of water quality parameters

PubMed Central

2014-01-01

This paper examined the efficiency of multivariate linear regression (MLR) and artificial neural network (ANN) models in prediction of two major water quality parameters in a wastewater treatment plant. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) as well as indirect indicators of organic matters are representative parameters for sewer water quality. Performance of the ANN models was evaluated using coefficient of correlation (r), root mean square error (RMSE) and bias values. The computed values of BOD and COD by model, ANN method and regression analysis were in close agreement with their respective measured values. Results showed that the ANN performance model was better than the MLR model. Comparative indices of the optimized ANN with input values of temperature (T), pH, total suspended solid (TSS) and total suspended (TS) for prediction of BOD was RMSE = 25.1 mg/L, r = 0.83 and for prediction of COD was RMSE = 49.4 mg/L, r = 0.81. It was found that the ANN model could be employed successfully in estimating the BOD and COD in the inlet of wastewater biochemical treatment plants. Moreover, sensitive examination results showed that pH parameter have more effect on BOD and COD predicting to another parameters. Also, both implemented models have predicted BOD better than COD. PMID:24456676

A reagent-free tubular biofilm reactor for on-line determination of biochemical oxygen demand.

PubMed

Liu, Changyu; Zhao, Huijun; Gao, Shan; Jia, Jianbo; Zhao, Limin; Yong, Daming; Dong, Shaojun

2013-07-15

We reported a reagent-free tubular biofilm reactor (BFR) based analytical system for rapid online biochemical oxygen demand (BOD) determination. The BFR was cultivated using microbial seeds from activated sludge. It only needs tap water to operate and does not require any chemical reagent. The analytical performance of this reagent-free BFR system was found to be equal to or better than the BFR system operated using phosphate buffer saline (PBS) and high purity deionized water. The system can readily achieve a limit of detection of 0.25 mg O2 L(-1), possessing superior reproducibility, and long-term operational and storage stability. More importantly, we confirmed for the first time that the BFR system is capable of tolerating common toxicants found in wastewaters, such as 3,5-dichlorophenol and Zn(II), Cr(VI), Cd(II), Cu(II), Pb(II), Mn(II) and Ni(II), enabling the method to be applied to a wide range of wastewaters. The sloughing and clogging are the important attributes affecting the operational stability, hence, the reliability of most online wastewater monitoring systems, which can be effectively avoided, benefiting from the tubular geometry of the reactor and high flow rate conditions. These advantages, coupled with simplicity in device, convenience in operation and minimal maintenance, make such a reagent-free BFR analytical system promising for practical BOD online determination. Copyright © 2013 Elsevier B.V. All rights reserved.

Divergent hypoxia tolerance in adult males and females of the plainfin midshipman (Porichthys notatus).

PubMed

LeMoine, Christophe M R; Bucking, Carol; Craig, Paul M; Walsh, Patrick J

2014-01-01

In the summer, the plainfin midshipman (Poricththys notatus) migrates to reproduce in the nearshore environment, where oxygen levels are influenced by the tidal cycles. Parental males establish nests under rocks in the intertidal zone, where they reside until the eggs they guard are fully developed. In contrast, females and sneaker males leave the nests shortly after spawning. We examined the physiological resistance and metabolic response of parental male and female adult midshipman to hypoxia to test whether they exhibited sex-specific differences reflecting their reproductive strategies. Further, we assessed whether metabolic enzymes and metabolites were differentially enriched in tissues of parental males and females to explain the differences observed in their hypoxia tolerance. While parental males and females exhibited similar depression of their oxygen consumption in response to graded hypoxia, parental males could withstand significantly longer exposures to severe hypoxic stress. At the biochemical level, parental males showed higher hepatic glycogen reserves and higher glycolytic enzyme capacities in gills and skeletal muscles than females. Although some of these enzymatic variations could be explained by differences in body size, we also observed a significant effect of sex on some of these factors. These results suggest that parental male midshipman may benefit from sexual dimorphism at the whole-organismal (larger body size) and biochemical (enzyme activities) levels, conferring on them a higher glycolytic potential to sustain the extensive hypoxia bouts they experience in nature.

A spectrophotometric biochemical oxygen demand determination method using 2,6-dichlorophenolindophenol as the redox color indicator and the eukaryote Saccharomyces cerevisiae.

PubMed

Nakamura, Hideaki; Kobayashi, Shun; Hirata, Yu; Suzuki, Kyota; Mogi, Yotaro; Karube, Isao

2007-10-15

A method to determine the spectrophotometric biochemical oxygen demand (BOD(sp)) was studied with high sensitivity and reproducibility by employing 2,6-dichlorophenolindophenol (DCIP) as a redox color indicator, the yeast Saccharomyces cerevisiae, and a temperature-controlling system providing a three-consecutive-stir unit. The absorbance of DCIP decreased due to the metabolism of organic substances in aqueous samples by S. cerevisiae. Under optimum conditions, a calibration curve for glucose glutamic acid concentration between 1.1 and 22mg O(2) L(-1) (r=0.988, six points, n=3) was obtained when the incubation mixture was incubated for 10min at 30 degrees C. The reproducibility of the optical responses in the calibration curve was 1.77% (average of relative standard deviations; RSD(av)). Subsequently, the characterization of this method was studied. The optical responses to pure organic substances and the influence of chloride ions, artificial seawater, and heavy metal ions on the sensor response were investigated before use with real samples. Measurements of real samples using river water were performed and compared with those obtained using the BOD(5) method. Finally, stable responses were obtained for 36 days when the yeast cell suspension was stored at 4 degrees C (response reduction, 89%; RSD(av) value for 9 testing days, 8.4%).

Oxygen toxicity.

PubMed

Stogner, S W; Payne, D K

1992-12-01

The objective of this article is to provide an overview of the biochemistry of oxygen metabolism, including the formation of free radicals and the role of endogenous antioxidants. Pathophysiologic correlates underlying the clinical manifestations of oxygen toxicity are reviewed and management strategies are outlined. References from basic science and clinical journals were selected from the authors' files and from a search of a computerized database of the biomedical literature. Articles selected for review included both historical and current literature concerning the biochemistry and pathophysiology of oxygen toxicity in animals and humans. The benefits of oxygen therapy have been known for many years; however, its potential toxicity has not been recognized until the last two decades. The lungs, the eyes, and, under certain conditions, the central nervous system are the organs most affected by prolonged exposure to hyperoxic environments. Free radical formation during cellular metabolism under hyperoxic conditions is recognized as the biochemical basis of oxygen injury to cells and organs. Endogenous antioxidants are a primary means of detoxifying reactive oxygen species and preventing hyperoxia-induced cellular damage. When this defense fails or is overwhelmed by the excessive production of hyperoxia-induced free-radical species, distinctive morphologic changes occur at the cellular level. The amount of hyperoxia required to cause cellular damage and the time course of these changes vary from species to species and from individual to individual within the same species. Age, nutritional status, presence of underlying diseases, and certain drugs may influence the development of oxygen toxicity. There is currently no reliably effective drug for preventing or delaying the development of oxygen toxicity in humans. Use of the lowest effective oxygen concentration, the avoidance of certain drugs, and attention to nutritional and metabolic factors remain the best means currently available to avoid or minimize oxygen toxicity. Research is continuing into more effective ways to prevent, diagnose, and treat this disorder.

Discovery, Biosynthesis and Stress-Related Accumulation of Dolabradiene-Derived Defenses in Maize1[OPEN

PubMed Central

Mafu, Sibongile; Addison, J. Bennett; Wang, Qiang; Hughes, Chambers C.; Betsiashvili, Mariam

2018-01-01

Terpenoids are a major component of maize (Zea mays) chemical defenses that mediate responses to herbivores, pathogens, and other environmental challenges. Here, we describe the biosynthesis and elicited production of a class of maize diterpenoids, named dolabralexins. Dolabralexin biosynthesis involves the sequential activity of two diterpene synthases, ENT-COPALYL DIPHOSPHATE SYNTHASE (ZmAN2) and KAURENE SYNTHASE-LIKE4 (ZmKSL4). Together, ZmAN2 and ZmKSL4 form the diterpene hydrocarbon dolabradiene. In addition, we biochemically characterized a cytochrome P450 monooxygenase, ZmCYP71Z16, which catalyzes the oxygenation of dolabradiene to yield the epoxides 15,16-epoxydolabrene (epoxydolabrene) and 3β-hydroxy-15,16-epoxydolabrene (epoxydolabranol). The absence of dolabradiene and epoxydolabranol in Zman2 mutants under elicited conditions confirmed the in vivo biosynthetic requirement of ZmAN2. Combined mass spectrometry and NMR experiments demonstrated that much of the epoxydolabranol is further converted into 3β,15,16-trihydroxydolabrene (trihydroxydolabrene). Metabolite profiling of field-grown maize root tissues indicated that dolabralexin biosynthesis is widespread across common maize cultivars, with trihydroxydolabrene as the predominant diterpenoid. Oxidative stress induced dolabralexin accumulation and transcript expression of ZmAN2 and ZmKSL4 in root tissues, and metabolite and transcript accumulation were up-regulated in response to elicitation with the fungal pathogens Fusarium verticillioides and Fusarium graminearum. Consistently, epoxydolabranol significantly inhibited the growth of both pathogens in vitro at 10 µg mL−1, while trihydroxydolabrene-mediated inhibition was specific to F. verticillioides. These findings suggest that dolabralexins have defense-related roles in maize stress interactions and expand the known chemical space of diterpenoid defenses as genetic targets for understanding and ultimately improving maize resilience. PMID:29475898

Comprehensive insights into the response of Alexandrium tamarense to algicidal component secreted by a marine bacterium.

PubMed

Lei, Xueqian; Li, Dong; Li, Yi; Chen, Zhangran; Chen, Yao; Cai, Guanjing; Yang, Xujun; Zheng, Wei; Zheng, Tianling

2015-01-01

Harmful algal blooms occur throughout the world, threatening human health, and destroying marine ecosystems. Alexandrium tamarense is a globally distributed and notoriously toxic dinoflagellate that is responsible for most paralytic shellfish poisoning incidents. The culture supernatant of the marine algicidal bacterium BS02 showed potent algicidal effects on A. tamarense ATGD98-006. In this study, we investigated the effects of this supernatant on A. tamarense at physiological and biochemical levels to elucidate the mechanism involved in the inhibition of algal growth by the supernatant of the strain BS02. Reactive oxygen species (ROS) levels increased following exposure to the BS02 supernatant, indicating that the algal cells had suffered from oxidative damage. The levels of cellular pigments, including chlorophyll a and carotenoids, were significantly decreased, which indicated that the accumulation of ROS destroyed pigment synthesis. The decline of the maximum photochemical quantum yield (Fv/Fm) and relative electron transport rate (rETR) suggested that the photosynthesis systems of algal cells were attacked by the BS02 supernatant. To eliminate the ROS, the activities of antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT), increased significantly within a short period of time. Real-time PCR revealed changes in the transcript abundances of two target photosynthesis-related genes (psbA and psbD) and two target respiration-related genes (cob and cox). The transcription of the respiration-related genes was significantly inhibited by the treatments, which indicated that the respiratory system was disturbed. Our results demonstrate that the BS02 supernatant can affect the photosynthesis process and might block the PS II electron transport chain, leading to the production of excessive ROS. The increased ROS can further destroy membrane integrity and pigments, ultimately inducing algal cell death.

Comprehensive insights into the response of Alexandrium tamarense to algicidal component secreted by a marine bacterium

PubMed Central

Lei, Xueqian; Li, Dong; Li, Yi; Chen, Zhangran; Chen, Yao; Cai, Guanjing; Yang, Xujun; Zheng, Wei; Zheng, Tianling

2015-01-01

Harmful algal blooms occur throughout the world, threatening human health, and destroying marine ecosystems. Alexandrium tamarense is a globally distributed and notoriously toxic dinoflagellate that is responsible for most paralytic shellfish poisoning incidents. The culture supernatant of the marine algicidal bacterium BS02 showed potent algicidal effects on A. tamarense ATGD98-006. In this study, we investigated the effects of this supernatant on A. tamarense at physiological and biochemical levels to elucidate the mechanism involved in the inhibition of algal growth by the supernatant of the strain BS02. Reactive oxygen species (ROS) levels increased following exposure to the BS02 supernatant, indicating that the algal cells had suffered from oxidative damage. The levels of cellular pigments, including chlorophyll a and carotenoids, were significantly decreased, which indicated that the accumulation of ROS destroyed pigment synthesis. The decline of the maximum photochemical quantum yield (Fv/Fm) and relative electron transport rate (rETR) suggested that the photosynthesis systems of algal cells were attacked by the BS02 supernatant. To eliminate the ROS, the activities of antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT), increased significantly within a short period of time. Real-time PCR revealed changes in the transcript abundances of two target photosynthesis-related genes (psbA and psbD) and two target respiration-related genes (cob and cox). The transcription of the respiration-related genes was significantly inhibited by the treatments, which indicated that the respiratory system was disturbed. Our results demonstrate that the BS02 supernatant can affect the photosynthesis process and might block the PS II electron transport chain, leading to the production of excessive ROS. The increased ROS can further destroy membrane integrity and pigments, ultimately inducing algal cell death. PMID:25667582

Curcumin ameliorates dopaminergic neuronal oxidative damage via activation of the Akt/Nrf2 pathway.

PubMed

Cui, Qunli; Li, Xin; Zhu, Hongcan

2016-02-01

Parkinson's disease (PD) is an age-related complex neurodegenerative disease that affects ≤ 80% of dopaminergic neurons in the substantia nigra pars compacta (SNpc). It has previously been suggested that mitochondrial dysfunction, oxidative stress and oxidative damage underlie the pathogenesis of PD. Curcumin, which is a major active polyphenol component extracted from the rhizomes of Curcuma longa (Zingiberaceae), has been reported to exert neuroprotective effects on an experimental model of PD. The present study conducted a series of in vivo experiments, in order to investigate the effects of curcumin on behavioral deficits, oxidative damage and related mechanisms. The results demonstrated that curcumin was able to significantly alleviate motor dysfunction and increase suppressed tyrosine hydroxylase (TH) activity in the SNpc of rotenone (ROT)-injured rats. Biochemical measurements indicated that rats pretreated with curcumin exhibited increased glutathione (GSH) levels, and reduced reactive oxygen species activity and malondialdehyde content. Mechanistic studies demonstrated that curcumin significantly restored the expression levels of heme oxygenase-1 and quinone oxidoreductase 1, thus ameliorating ROT-induced damage in vivo, via the phosphorylation of Akt and nuclear factor erythroid 2-related factor 2 (Nrf2). Further studies indicated that the Akt/Nrf2 signaling pathway was associated with the protective role of curcumin in ROT-treated rats. Inhibiting the Akt/Nrf2 pathway using a lentiviral vector containing Nrf2-specific short hairpin RNA, or the phosphoinositide 3-kinase inhibitor LY294002, markedly reduced the expression levels of TH and GSH, ultimately attenuating the neuroprotective effects of curcumin against oxidative damage. These results indicated that curcumin was able to significantly ameliorate ROT-induced dopaminergic neuronal oxidative damage in the SNpc of rats via activation of the Akt/Nrf2 signaling pathway.

Low-temperature thermal pre-treatment of municipal wastewater sludge: Process optimization and effects on solubilization and anaerobic degradation.

PubMed

Nazari, Laleh; Yuan, Zhongshun; Santoro, Domenico; Sarathy, Siva; Ho, Dang; Batstone, Damien; Xu, Chunbao Charles; Ray, Madhumita B

2017-04-15

The present study examines the relationship between the degree of solubilization and biodegradability of wastewater sludge in anaerobic digestion as a result of low-temperature thermal pre-treatment. The main effect of thermal pre-treatment is the disintegration of cell membranes and thus solubilization of organic compounds. There is an established correlation between chemical oxygen demand (COD) solubilization and temperature of thermal pre-treatment, but results of thermal pre-treatment in terms of biodegradability are not well understood. Aiming to determine the impact of low temperature treatments on biogas production, the thermal pre-treatment process was first optimized based on an experimental design study on waste activated sludge in batch mode. The optimum temperature, reaction time and pH of the process were determined to be 80 °C, 5 h and pH 10, respectively. All three factors had a strong individual effect (p < 0.001), with a significant interaction effect for temp. pH 2 (p = 0.002). Thermal pre-treatments, carried out on seven different municipal wastewater sludges at the above optimum operating conditions, produced increased COD solubilization of 18.3 ± 7.5% and VSS reduction of 27.7 ± 12.3% compared to the untreated sludges. The solubilization of proteins was significantly higher than carbohydrates. Methane produced in biochemical methane potential (BMP) tests, indicated initial higher rates (p = 0.0013) for the thermally treated samples (k hyd up to 5 times higher), although the ultimate methane yields were not significantly affected by the treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insights into the importance for designing curcumin-inspired anticancer agents by a prooxidant strategy: The case of diarylpentanoids.

PubMed

Dai, Fang; Liu, Guo-Yun; Li, Yan; Yan, Wen-Jing; Wang, Qi; Yang, Jie; Lu, Dong-Liang; Ding, De-Jun; Lin, Dong; Zhou, Bo

2015-08-01

Developing anticancer agents by a prooxidant strategy has attracted increasing attention in recent years, although it is not conventional in medicinal chemistry and is completely opposite to antioxidant therapy. In this work, a panel of diarylpentanoids as the curcumin mono-carbonyl analogs were designed and synthesized, and their cytotoxic and proapoptotic mechanisms against human lung cancer A549 cells were investigated at the frontiers of chemistry and biology. It was found that compared with curcumin, the compounds (A1, B1, and C1) bearing two ortho substituents on the aromatic rings, especially A1, exhibit significantly increased cytotoxic and proapoptotic activities through a Michael acceptor unit-dependent prooxidant-mediated mechanism. The prooxidative ability is governed not only by their electrophilicity but also by their geometry, cellular uptake and metabolic stability, and TrxR-inhibitory activity. Mechanistic investigation reveals that the compound A1 could effectively and irreversibly modify the TrxR by virtue of the above optimal biochemical parameters, and convert this antioxidant enzyme into a reactive oxygen species (ROS) promoter, resulting in a burst of the intracellular ROS including H2O2 and O2(-)•. The ROS generation is associated with falling apart in the redox buffering system, and subsequently induces increases in Ca(2+) influx and oxidative stress, collapse of mitochondrial membrane potential, and activation of caspase-9 and caspase-3, ultimately leading to cell apoptosis. This work highlights the feasibility in designing curcumin-inspired anticancer agents by a prooxidant strategy, and gives us useful information on how to design them. Copyright © 2015 Elsevier Inc. All rights reserved.

Are All-Solid-State Lithium-Ion Batteries Really Safe?-Verification by Differential Scanning Calorimetry with an All-Inclusive Microcell.

PubMed

Inoue, Takao; Mukai, Kazuhiko

2017-01-18

Although all-solid-state lithium-ion batteries (ALIBs) have been believed as the ultimate safe battery, their true character has been an enigma so far. In this paper, we developed an all-inclusive-microcell (AIM) for differential scanning calorimetry (DSC) analysis to clarify the degree of safety (DOS) of ALIBs. Here AIM possesses all the battery components to work as a battery by itself, and DOS is determined by the total heat generation ratio (ΔH) of ALIB compared with the conventional LIB. When DOS = 100%, the safety of ALIB is exactly the same as that of LIB; when DOS = 0%, ALIB reaches the ultimate safety. We investigated two types of LIB-AIM and three types of ALIB-AIM. Surprisingly, all the ALIBs exhibit one or two exothermic peaks above 250 °C with 20-30% of DOS. The exothermic peak is attributed to the reaction between the released oxygen from the positive electrode and the Li metal in the negative electrode. Hence, ALIBs are found to be flammable as in the case of LIBs. We also attempted to improve the safety of ALIBs and succeeded in decreasing the DOS down to ∼16% by incorporating Ketjenblack into the positive electrode as an oxygen scavenger. Based on ΔH as a function of voltage window, a safety map for LIBs and ALIBs is proposed.

Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons.

PubMed

Meckenstock, Rainer U; Boll, Matthias; Mouttaki, Housna; Koelschbach, Janina S; Cunha Tarouco, Paola; Weyrauch, Philip; Dong, Xiyang; Himmelberg, Anne M

2016-01-01

Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers. © 2016 S. Karger AG, Basel.

Physiological and lavage fluid cytological and biochemical endpoints of toxicity in the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehnert, B.E.

1992-01-01

Exposure of the respiratory tract to toxic materials can result in a variety of physiologic disturbances that can serve as endpoints of toxicity. In addition to a brief review of commonly assessed physiologic endpoints, attention is given in the first component of this report to the use of both nose breathing and mouth'' breathing rats in toxicity studies that involve measurements of ventilatory functional changes in response to test atmospheres. Additionally, the usefulness of maximum oxygen consumption, or VO[sub 2max], as a physiologic endpoint of toxicity that uses exercising rats after exposure to test atmospheres is described, along with anmore » introduction to post-exposure exercise as an important behavioral activity that can markedly impact on the severity of acute lung injury caused by pneumoedematogenic materials. The second component of this report focuses on bronchoalveolar lavage and cytological and biochemical endpoints that can be assessed in investigations of the toxicities of test materials. As will be shown herein, some of the biochemical endpoints of toxicity, especially, can sensitively detect subtle injury to the lower respiratory tract that may escape detection by changes in some other conventional endpoints of toxicity, including lung gravimetric increases and histopathological alterations.« less

Physiological and lavage fluid cytological and biochemical endpoints of toxicity in the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehnert, B.E.

1992-12-31

Exposure of the respiratory tract to toxic materials can result in a variety of physiologic disturbances that can serve as endpoints of toxicity. In addition to a brief review of commonly assessed physiologic endpoints, attention is given in the first component of this report to the use of both nose breathing and ``mouth`` breathing rats in toxicity studies that involve measurements of ventilatory functional changes in response to test atmospheres. Additionally, the usefulness of maximum oxygen consumption, or VO{sub 2max}, as a physiologic endpoint of toxicity that uses exercising rats after exposure to test atmospheres is described, along with anmore » introduction to post-exposure exercise as an important behavioral activity that can markedly impact on the severity of acute lung injury caused by pneumoedematogenic materials. The second component of this report focuses on bronchoalveolar lavage and cytological and biochemical endpoints that can be assessed in investigations of the toxicities of test materials. As will be shown herein, some of the biochemical endpoints of toxicity, especially, can sensitively detect subtle injury to the lower respiratory tract that may escape detection by changes in some other conventional endpoints of toxicity, including lung gravimetric increases and histopathological alterations.« less

Thermodynamic model of Mars Oxygen ISRU Experiment (MOXIE)

NASA Astrophysics Data System (ADS)

Meyen, Forrest E.; Hecht, Michael H.; Hoffman, Jeffrey A.; MOXIE Team

2016-12-01

As humankind expands its footprint in the solar system, it is increasingly important to make use of the resources already in our solar system to make these missions economically feasible and sustainable. In-Situ Resource Utilization (ISRU), the science of using resources at a destination to support exploration missions, unlocks potential destinations by significantly reducing the amount of resources that need to be launched from Earth. Carbon dioxide is an example of an in-situ resource that comprises 96% of the Martian atmosphere and can be used as a source of oxygen for propellant and life support systems. The Mars Oxygen ISRU Experiment (MOXIE) is a payload being developed for NASA's upcoming Mars 2020 rover. MOXIE will produce oxygen from the Martian atmosphere using solid oxide electrolysis (SOXE). MOXIE is on the order of magnitude of a 1% scale model of an oxygen processing plant that might enable a human expedition to Mars in the 2030s through the production of the oxygen needed for the propellant of a Mars ascent vehicle. MOXIE is essentially an energy conversion system that draws energy from the Mars 2020 rover's radioisotope thermoelectric generator and ultimately converts it to stored energy in oxygen and carbon monoxide molecules. A thermodynamic model of this novel system is used to understand this process in order to derive operating parameters for the experiment. This paper specifically describes the model of the SOXE component. Assumptions and idealizations are addressed, including 1D and 2D simplifications. Operating points are discussed as well as impacts of flow rates and production.

The effect of laparotomy on hydroxyl radicals, singlet oxygen and antioxidants measured by EPR method in the tails of rats.

PubMed

Fricova, Jitka; Stopka, Pavel; Krizova, Jana; Yamamotova, Anna; Rokyta, Richard

2009-01-01

The aim of the study was to demonstrate that direct measurement of hydroxyl radicals and singlet oxygen in the tail of living rats is possible. The basic level of hydroxyl radicals and singlet oxygen were measured and the effects of antioxidants on their levels were studied in the tail of living anaesthetized rats after acute postoperative pain. Laparotomy was performed as the source of acute abdominal pain. After closure of the abdominal cavity, the animals began to awaken within 30-60 minutes. They were left to recover for 2-3 hours; then they were reanesthetized and the effect of antioxidants was measured on the numbers of hydroxyl radicals and singlet oxygen via blood in the tail. The laparotomy was preformed under general anesthesia (Xylazin and Ketamin) using Wistar rats. After recovery and several hours of consciousness they were reanaesthetized and free radicals and singlet oxygen were measured. An antioxidant mixture (vitamins A, C, D and Selenium) was administered intramuscularly prior to the laparotomy. All measurements were done on the tail of anaesthetized animals. In this particular article, the effect of antioxidants is only reported for hydroxyl radicals. After laparotomy, which represented both somatic and visceral pain, hydroxyl radicals and singlet oxygen were increased. Antioxidant application prior to laparotomy decreased the numbers of hydroxyl radicals. Results are in agreement with our previous finding regarding the increase in hydroxyl free radicals and singlet oxygen following nociceptive stimulation, in this case a combination of both somatic and visceral pain. The administered antioxidants mitigated the increase. This is further confirmation that direct measurement of free radicals and singlet oxygen represents a very useful method for the biochemical evaluation of pain and nociception.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Cedar Creek, Dekalb and Allen counties, Indiana

USGS Publications Warehouse

Wilber, William G.; Peters, J.G.; Ayers, M.A.; Crawford, Charles G.

1979-01-01

A digital model calibrated to conditions in Cedar Creek was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that the dissolved-oxygen concentration of the Auburn wastewater effluent and nitrification are the most significant factors affecting the dissolved-oxygen concentration in Cedar Creek during summer low flows. The observed dissolved-oxygen concentration of the Auburn wastewater effluent was low and averaged 30 percent of saturation. Projected nitrogenous biochemical-oxygen demand loads, from the Indiana State Board of Health, for the Auburn and Waterloo wastewater-treatment facilities will result in violations of the current instream dissolved-oxygen standard (5 mg/l), even with an effluent dissolved-oxygen concentration of 80 percent saturation. Natural streamflow for Cedar Creek upstream from the confluence of Willow and Little Cedar Creeks is small compared with the waste discharge, so benefits of dilution for Waterloo and Auburn are minimal. The model also indicates that, during winter low flows, ammonia toxicity, rather than dissolved oxygen, is the limiting water-quality criterion in the reach of Cedar Creek downstream from the wastewater-treatment facility at Auburn and the confluence of Garrett ditch. Ammonia-nitrogen concentrations predicted for 1978 through 2000 downstream from the Waterloo wastewater-treatment facility do not exceed Indiana water-quality standards for streams. Calculations of the stream 's assimilative capacity indicate that future waste discharge in the Cedar Creek basin will be limited to the reaches between the Auburn wastewater-treatment facility and County Road 68. (Kosco-USGS)

Cerebral Effect of Intratracheal Aerosolized Surfactant Versus Bolus Therapy in Preterm Lambs.

PubMed

Rey-Santano, Carmen; Mielgo, Victoria E; López-de-Heredia-y-Goya, Jon; Murgia, Xabier; Valls-i-Soler, Adolfo

2016-04-01

Aerosolization has been proposed as a useful alternative to rapid intratracheal instillation for the delivery of exogenous surfactant in neonatal respiratory distress syndrome. However, there is a lack of information regarding the likely safety of this new therapeutic approach for the neonatal brain. We aimed to compare the cerebral effects of aerosolized versus bolus surfactant administration in premature lambs with respiratory distress syndrome. Prospective randomized study. BioCruces Institute Animal Research Facility. Fourteen intensively monitored and mechanically ventilated preterm lambs. Preterm lambs were randomly assigned to receive intratracheal aerosolized surfactant or bolus surfactant. Brain hemodynamics (cerebral and regional cerebral blood flow) and cerebral oxygen metabolism (cerebral oxygen delivery, cerebral metabolic rate of oxygen, and oxygen extraction fraction) were measured every 30 minutes for 6 hours. We also performed cerebral biochemical and histological analysis. In preterm lambs with respiratory distress syndrome, cerebral blood flow, regional cerebral blood flow, cerebral oxygen delivery, and cerebral metabolic rate of oxygen increased significantly in the bolus surfactant group during the first 5 minutes, without changes in cerebral oxygen extraction fraction. By 60 minutes, all parameters had decreased in both groups, cerebral blood flow and regional cerebral blood flow (in inner and cerebellum brainstem regions) remaining higher in the bolus surfactant than in the aerosolized surfactant group. Overall, the impact of aerosol surfactant was not significantly different to that of bolus surfactant in terms of cerebral necrosis, edema, inflammation, hemorrhage, infarct, apoptosis, or oxidative stress. In preterm lambs with severe respiratory distress syndrome, aerosol surfactant administration seems to be as safe as bolus administration, showing more stable cerebral hemodynamics and cerebral oxygen metabolism to the same dose of surfactant administered as a standard bolus.

Interplay between oxygen and Fe-S cluster biogenesis: insights from the Suf pathway.

PubMed

Boyd, Eric S; Thomas, Khaleh M; Dai, Yuyuan; Boyd, Jeff M; Outten, F Wayne

2014-09-23

Iron-sulfur (Fe-S) cluster metalloproteins conduct essential functions in nearly all contemporary forms of life. The nearly ubiquitous presence of Fe-S clusters and the fundamental requirement for Fe-S clusters in both aerobic and anaerobic Archaea, Bacteria, and Eukarya suggest that these clusters were likely integrated into central metabolic pathways early in the evolution of life prior to the widespread oxidation of Earth's atmosphere. Intriguingly, Fe-S cluster-dependent metabolism is sensitive to disruption by oxygen because of the decreased bioavailability of ferric iron as well as direct oxidation of sulfur trafficking intermediates and Fe-S clusters by reactive oxygen species. This fact, coupled with the ubiquity of Fe-S clusters in aerobic organisms, suggests that organisms evolved with mechanisms that facilitate the biogenesis and use of these essential cofactors in the presence of oxygen, which gradually began to accumulate around 2.5 billion years ago as oxygenic photosynthesis proliferated and reduced minerals that buffered against oxidation were depleted. This review highlights the most ancient of the Fe-S cluster biogenesis pathways, the Suf system, which likely was present in early anaerobic forms of life. Herein, we use the evolution of the Suf pathway to assess the relationships between the biochemical functions and physiological roles of Suf proteins, with an emphasis on the selective pressure of oxygen toxicity. Our analysis suggests that diversification into oxygen-containing environments disrupted iron and sulfur metabolism and was a main driving force in the acquisition of accessory Suf proteins (such as SufD, SufE, and SufS) by the core SufB-SufC scaffold complex. This analysis provides a new framework for the study of Fe-S cluster biogenesis pathways and Fe-S cluster-containing metalloenzymes and their complicated patterns of divergence in response to oxygen.

Myocardial perfusion and oxidative stress after 21% vs. 100% oxygen ventilation and uninterrupted chest compressions in severely asphyxiated piglets.

PubMed

Solevåg, Anne Lee; Schmölzer, Georg M; O'Reilly, Megan; Lu, Min; Lee, Tze-Fun; Hornberger, Lisa K; Nakstad, Britt; Cheung, Po-Yin

2016-09-01

Despite the minimal evidence, neonatal resuscitation guidelines recommend using 100% oxygen when chest compressions (CC) are needed. Uninterrupted CC in adult cardiopulmonary resuscitation (CPR) may improve CPR hemodynamics. We aimed to examine 21% oxygen (air) vs. 100% oxygen in 3:1 CC:ventilation (C:V) CPR or continuous CC with asynchronous ventilation (CCaV) in asphyxiated newborn piglets following cardiac arrest. Piglets (1-3 days old) were progressively asphyxiated until cardiac arrest and randomized to 4 experimental groups (n=8 each): air and 3:1 C:V CPR, 100% oxygen and 3:1 C:V CPR, air and CCaV, or 100% oxygen and CCaV. Time to return of spontaneous circulation (ROSC), mortality, and clinical and biochemical parameters were compared between groups. We used echocardiography to measure left ventricular (LV) stroke volume at baseline, at 30min and 4h after ROSC. Left common carotid artery blood pressure was measured continuously. Time to ROSC (heart rate ≥100min(-1)) ranged from 75 to 592s and mortality 50-75%, with no differences between groups. Resuscitation with air was associated with higher LV stroke volume after ROSC and less myocardial oxidative stress compared to 100% oxygen groups. CCaV was associated with lower mean arterial blood pressure after ROSC and higher myocardial lactate than those of 3:1 C:V CPR. In neonatal asphyxia-induced cardiac arrest, using air during CC may reduce myocardial oxidative stress and improve cardiac function compared to 100% oxygen. Although overall recovery may be similar, CCaV may impair tissue perfusion compared to 3:1 C:V CPR. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Up-regulation of A1M/α1-microglobulin in skin by heme and reactive oxygen species gives protection from oxidative damage.

PubMed

Olsson, Magnus G; Allhorn, Maria; Larsson, Jörgen; Cederlund, Martin; Lundqvist, Katarina; Schmidtchen, Artur; Sørensen, Ole E; Mörgelin, Matthias; Akerström, Bo

2011-01-01

During bleeding the skin is subjected to oxidative insults from free heme and radicals, generated from extracellular hemoglobin. The lipocalin α(1)-microglobulin (A1M) was recently shown to have reductase properties, reducing heme-proteins and other substrates, and to scavenge heme and radicals. We investigated the expression and localization of A1M in skin and the possible role of A1M in the protection of skin tissue from damage induced by heme and reactive oxygen species. Skin explants, keratinocyte cultures and purified collagen I were exposed to heme, reactive oxygen species, and/or A1M and investigated by biochemical methods and electron microscopy. The results demonstrate that A1M is localized ubiquitously in the dermal and epidermal layers, and that the A1M-gene is expressed in keratinocytes and up-regulated after exposure to heme and reactive oxygen species. A1M inhibited the heme- and reactive oxygen species-induced ultrastructural damage, up-regulation of antioxidation and cell cycle regulatory genes, and protein carbonyl formation in skin and keratinocytes. Finally, A1M bound to purified collagen I (K(d) = 0.96×10(-6) M) and could inhibit and repair the destruction of collagen fibrils by heme and reactive oxygen species. The results suggest that A1M may have a physiological role in protection of skin cells and matrix against oxidative damage following bleeding.

Computational modelling of oxygenation processes in enzymes and biomimetic model complexes.

PubMed

de Visser, Sam P; Quesne, Matthew G; Martin, Bodo; Comba, Peter; Ryde, Ulf

2014-01-11

With computational resources becoming more efficient and more powerful and at the same time cheaper, computational methods have become more and more popular for studies on biochemical and biomimetic systems. Although large efforts from the scientific community have gone into exploring the possibilities of computational methods for studies on large biochemical systems, such studies are not without pitfalls and often cannot be routinely done but require expert execution. In this review we summarize and highlight advances in computational methodology and its application to enzymatic and biomimetic model complexes. In particular, we emphasize on topical and state-of-the-art methodologies that are able to either reproduce experimental findings, e.g., spectroscopic parameters and rate constants, accurately or make predictions of short-lived intermediates and fast reaction processes in nature. Moreover, we give examples of processes where certain computational methods dramatically fail.

Ozone pretreatment of olive mill wastewaters (OMW) and its effect on OMW biochemical methane potential (BMP).

PubMed

Tsintavi, E; Pontillo, N; Dareioti, M A; Kornaros, M

2013-01-01

The possibility of coupling a physicochemical pretreatment (ozonation) with a biological treatment (anaerobic digestion) was investigated for the case of olive mill wastewaters (OMW). Batch ozonation experiments were performed in a glass bubble reactor. The parameters which were tested included the ozone concentration in the inlet gas stream, the reactor temperature and the composition of the liquid medium in terms of raw or fractionated OMW used. In the sequel, ozone-pretreated OMW samples were tested for their biochemical methane potential (BMP) under mesophilic conditions and these results were compared to the BMP of untreated OMW. The ozonation process alone resulted in a 57-76% decrease of total phenols and a 5-18% decrease of total carbohydrates contained in OMW, depending on the experimental conditions. Nevertheless, the ozone-pretreated OMW exhibited lower chemical oxygen demand removal and methane production during BMP testing compared to the untreated OMW.

Biochemical methane potential (BMP) of artichoke waste: the inoculum effect.

PubMed

Fabbri, Andrea; Serranti, Silvia; Bonifazi, Giuseppe

2014-03-01

The aim of this work was to investigate anaerobic digestibility of artichoke waste resulting from industrial transformation. A series of batch anaerobic digestion tests was performed in order to evaluate the biochemical methane potential of the matrix in respect of the process. A comparison of the different performances of the laboratory-scale reactors operating in mesophilic conditions and utilizing three different values of the inoculum/substrate ratio was carried out. The best performance was achieved with an inoculum/substrate ratio of 2. Artichoke-processing byproducts showed a classical organic waste decomposition behaviour: a fast start-up phase, an acclimation stage, and a final stabilization phase. Following this approach, artichoke waste reached chemical oxygen demand removal of about 90% in 40 days. The high methane yield (average 408.62 mL CH4 gvs (-1) voltatile solids), makes artichoke waste a good product to be utilized in anaerobic digestion plants for biogas production.

Influence of headspace flushing on methane production in Biochemical Methane Potential (BMP) tests.

PubMed

Koch, Konrad; Bajón Fernández, Yadira; Drewes, Jörg E

2015-06-01

The influence of headspace flushing on the specific methane (CH4) production of blank samples with just inoculum in Biochemical Methane Potential (BMP) tests was studied. The three most common ways were applied: flushing with nitrogen (N2) gas, flushing with a mixture of N2 and CO2 (80/20 v/v), and no flushing. The results revealed that removing the oxygen is crucial to avoid aerobic respiration, which caused both hindered activity of methanogens and loss of methane potential. Furthermore it was demonstrated that 20% of CO2 in the flush gas increased significantly the methane production by over 20% compared to the flushing with pure N2. In order to mimic the same headspace conditions as in full-scale treatment plants, using a flush gas with a similar CO2 concentration as the expected biogas is suggested. Copyright © 2015 Elsevier Ltd. All rights reserved.

Blood biochemical and cellular changes during decompression and simulated extravehicular activity

NASA Technical Reports Server (NTRS)

Jauchem, J. R.; Waligora, J. M.; Johnson, P. C. Jr

1990-01-01

Blood biochemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 6 h of oxygen prebreathing. The exposure was designed to simulate extravehicular activity for 6 h (subjects performed exercise while exposed to 29.6 kPa). There were no significant differences between blood samples from subjects who were susceptible (n = 11) versus those who were resistant (n = 27) to formation of venous gas emboli. Although several statistically significant (P less than 0.05) changes in blood parameters were observed following the exposure (increases in white blood cell count, prothrombin time, and total bilirubin, and decreases in triglycerides, very-low-density lipoprotein cholesterol, and blood urea nitrogen), the changes were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression schedule used in this study is not likely to result in blood changes that would pose a threat to astronauts during extravehicular activity.

[The biochemical carcinogenesis of selected heavy metals in bladder cancer].

PubMed

Rorbach-Dolata, Anna; Marchewka, Zofia; Piwowar, Agnieszka

2015-01-01

Bladder cancer takes the second place in the classification of morbidity of urinary system cancers. Many chemical factors take part in cancerogenesis. It is suggested that exposure to heavy metals such as arsenic, chromium, nickel and cadmium as well as its metabolites may trigger the bladder cancer through inducing excessive reactive oxygen species production and oxidative stress formation which are responsible for DNA damage. In patients with bladder cancer is observed the disorder of processes regulated by p-53, including apoptosis. There are many patients with bladder cancer with confirmed absence of retinoblastoma protein, which is responsible of holding on the process of coming up the cells with mutation into synthesis, where the replication process undergoes. It is mentioned that excessive expression of proto-oncogenes may also cause the bladder cancer. The article concerns biochemical effects of exposure to chosen heavy metals and their potential role in bladder cancer progression.

Consequences of Atomic Oxygen Interaction With Silicone and Silicone Contamination on Surfaces in Low Earth Orbit

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Rutledge, Sharon K.; Haytas, Christy A.

1999-01-01

The exposure of silicones to atomic oxygen in low Earth orbit causes oxidation of the surface, resulting in conversion of silicone to silica. This chemical conversion increases the elastic modulus of the surface and initiates the development of a tensile strain. Ultimately, with sufficient exposure, tensile strain leads to cracking of the surface enabling the underlying unexposed silicone to be converted to silica resulting in additional depth and extent of cracking. The use of silicone coatings for the protection of materials from atomic oxygen attack is limited because of the eventual exposure of underlying unprotected polymeric material due to deep tensile stress cracking of the oxidized silicone. The use of moderate to high volatility silicones in low Earth orbit has resulted in a silicone contamination arrival at surfaces which are simultaneously being bombarded with atomic oxygen, thus leading to conversion of the silicone contaminant to silica. As a result of these processes, a gradual accumulation of contamination occurs leading to deposits which at times have been up to several microns thick (as in the case of a Mir solar array after 10 years in space). The contamination species typically consist of silicon, oxygen and carbon. which in the synergistic environment of atomic oxygen and UV radiation leads to increased solar absorptance and reduced solar transmittance. A comparison of the results of atomic oxygen interaction with silicones and silicone contamination will be presented based on the LDEF, EOIM-111, Offeq-3 spacecraft and Mir solar array in-space results. The design of a contamination pin-hole camera space experiment which uses atomic oxygen to produce an image of the sources of silicone contamination will also be presented.

Electrons, life and the evolution of Earth's oxygen cycle.

PubMed

Falkowski, Paul G; Godfrey, Linda V

2008-08-27

The biogeochemical cycles of H, C, N, O and S are coupled via biologically catalysed electron transfer (redox) reactions. The metabolic processes responsible for maintaining these cycles evolved over the first ca 2.3 Ga of Earth's history in prokaryotes and, through a sequence of events, led to the production of oxygen via the photobiologically catalysed oxidation of water. However, geochemical evidence suggests that there was a delay of several hundred million years before oxygen accumulated in Earth's atmosphere related to changes in the burial efficiency of organic matter and fundamental alterations in the nitrogen cycle. In the latter case, the presence of free molecular oxygen allowed ammonium to be oxidized to nitrate and subsequently denitrified. The interaction between the oxygen and nitrogen cycles in particular led to a negative feedback, in which increased production of oxygen led to decreased fixed inorganic nitrogen in the oceans. This feedback, which is supported by isotopic analyses of fixed nitrogen in sedimentary rocks from the Late Archaean, continues to the present. However, once sufficient oxygen accumulated in Earth's atmosphere to allow nitrification to out-compete denitrification, a new stable electron 'market' emerged in which oxygenic photosynthesis and aerobic respiration ultimately spread via endosymbiotic events and massive lateral gene transfer to eukaryotic host cells, allowing the evolution of complex (i.e. animal) life forms. The resulting network of electron transfers led a gas composition of Earth's atmosphere that is far from thermodynamic equilibrium (i.e. it is an emergent property), yet is relatively stable on geological time scales. The early coevolution of the C, N and O cycles, and the resulting non-equilibrium gaseous by-products can be used as a guide to search for the presence of life on terrestrial planets outside of our Solar System.

A dissolved cobalt plume in the oxygen minimum zone of the eastern tropical South Pacific

NASA Astrophysics Data System (ADS)

Hawco, Nicholas J.; Ohnemus, Daniel C.; Resing, Joseph A.; Twining, Benjamin S.; Saito, Mak A.

2016-10-01

Cobalt is a nutrient to phytoplankton, but knowledge about its biogeochemical cycling is limited, especially in the Pacific Ocean. Here, we report sections of dissolved cobalt and labile dissolved cobalt from the US GEOTRACES GP16 transect in the South Pacific. The cobalt distribution is closely tied to the extent and intensity of the oxygen minimum zone in the eastern South Pacific with highest concentrations measured at the oxycline near the Peru margin. Below 200 m, remineralization and circulation produce an inverse relationship between cobalt and dissolved oxygen that extends throughout the basin. Within the oxygen minimum zone, elevated concentrations of labile cobalt are generated by input from coastal sources and reduced scavenging at low O2. As these high cobalt waters are upwelled and advected offshore, phytoplankton export returns cobalt to low-oxygen water masses underneath. West of the Peru upwelling region, dissolved cobalt is less than 10 pM in the euphotic zone and strongly bound by organic ligands. Because the cobalt nutricline within the South Pacific gyre is deeper than in oligotrophic regions in the North and South Atlantic, cobalt involved in sustaining phytoplankton productivity in the gyre is heavily recycled and ultimately arrives from lateral transport of upwelled waters from the eastern margin. In contrast to large coastal inputs, atmospheric deposition and hydrothermal vents along the East Pacific Rise appear to be minor sources of cobalt. Overall, these results demonstrate that oxygen biogeochemistry exerts a strong influence on cobalt cycling.

Lunar Resource Assessment: Strategies for Surface Exploration

NASA Technical Reports Server (NTRS)

Spudis, Paul D.

1992-01-01

Use of the indigenous resources of space to support long-term human presence is an essential element of the settlement of other planetary bodies. We are in a very early stage of understanding exactly how and under what circumstances space resources will become important. The materials and processes to recover them that we now think are critical may not ultimately be the raison d'etre for a resource utilization program. However, the need for strategic thinking proceeds in parallel with efforts to implement such plans and it is not too soon to begin thinking how we could and should use the abundant resources of materials and energy available from the Moon. The following commodities from the Moon are discussed: (1) bulk regolith, for shielding and construction on the lunar surface (ultimately for export to human-tended stations in Earth-Moon space), and (2) oxygen and hydrogen, for propellant and life support.

Ribose in the heart.

PubMed

Herrick, James; St Cyr, John

2008-01-01

Every cell needs energy, i.e., adenosine triphosphate (ATP), to carry out its function. Decreased oxygen levels, decreased blood flow, and other stressful conditions can drastically effect the intracellular concentrations of these energy compounds. Skeletal muscle, unlike the heart, can address this drop in ATP by employing the myokinase reaction, ultimately producing ATP with a subsequent elevation in adenosine monophosphate (AMP). Ribose, a naturally occurring 5-carbon monosaccharide, is a key component of RNA, DNA (which has deoxyribose), acetyl coenzyme A, and ATP. Each cell produces its own ribose, involved in the pentose phosphate pathway (PPP), to aid in ATP production. States of ischemia and/or hypoxia can severely lower levels of cellular energy compounds in the heart, with an associated compromise in cellular processes, ultimately reflected in altered function. Ribose appears to provide a solution to the problem in replenishing the depressed ATP levels and improving functional status of patients afflicted with cardiovascular diseases.

Relation of urban land-use and land-surface characteristics to quantity and quality of storm runoff in two basins in California

USGS Publications Warehouse

Sylvester, Marc A.; Brown, William M.

1978-01-01

Two basins (Castro Valley Creek, in Alameda County, and Strong Ranch Slough, in Sacramento County) in the San Francisco Bay and Sacramento-San Joaquin Delta region (Bay-Delta region) were sampled intensively (3-15 minute intervals) during three storms between October 1974 and April 1975. Both basins are primarily residential, but the Strong Ranch Slough basin is almost entirely urbanized and nearly flat, while the Castro Valley Creek basin possesses some rural areas and slopes greater than 70 percent in the headwaters. Water discharge and concentrations of suspended solids, chemical oxygen demand, 5-day biochemical oxygen demand, nitrite and nitrate, total Kjeldahl nitrogen, total orthophosphorus, and settleable matter were usually greater at the Castro Valley Creek basin than at the Strong Ranch Slough basin. Concentrations of these constituents and water discharge changed more rapidly at the Castro Valley Creek basin than at the Strong Ranch Slough basin. Of the four subbasins sampled (two in each basin), constituent concentrations in runoff from a residential subbasin were usually greatest. Quantity and quality of runoff were related to environmental characteristics such as slope, perviousness, residential development and maintenance, and channel conditions. Greater water discharge and concentrations of constituents in the Castro Valley Creek basin seem to be partly due to steeper slopes, less perviousness, and smaller residential lot sizes than are in the Strong Ranch Slough basin. Erosion of steep slopes disturbed by grazing and residential development, poorly maintained dwellings and lots, and a mostly earthen drainage channel in the Castro Valley Creek basin are probably responsible for the greater concentrations of suspended solids and settleable matter in runoff from this basin. In both basins, the highest observed concentrations of suspended solids, chemical oxygen demand, 5-day biochemical oxygen demand, settleable matter, total Kjeldahl nitrogen, and total orthophosphorus were observed at or near peak water discharges. Flow-weighted and arithmetic-mean concentrations of suspended solids in Castro Valley Creek exceed the arithmetic-mean concentration of suspended solids in medium-strength untreated sewage. These results indicate that control of urban storm runoff in the Bay-Delta region may be desirable to protect receiving water.

Arsenic Uptake, Toxicity, Detoxification, and Speciation in Plants: Physiological, Biochemical, and Molecular Aspects

PubMed Central

Abbas, Ghulam; Murtaza, Behzad; Bibi, Irshad; Shahid, Muhammad; Khan, Muhammad Imran; Amjad, Muhammad; Hussain, Munawar; Natasha

2018-01-01

Environmental contamination with arsenic (As) is a global environmental, agricultural and health issue due to the highly toxic and carcinogenic nature of As. Exposure of plants to As, even at very low concentration, can cause many morphological, physiological, and biochemical changes. The recent research on As in the soil-plant system indicates that As toxicity to plants varies with its speciation in plants (e.g., arsenite, As(III); arsenate, As(V)), with the type of plant species, and with other soil factors controlling As accumulation in plants. Various plant species have different mechanisms of As(III) or As(V) uptake, toxicity, and detoxification. This review briefly describes the sources and global extent of As contamination and As speciation in soil. We discuss different mechanisms responsible for As(III) and As(V) uptake, toxicity, and detoxification in plants, at physiological, biochemical, and molecular levels. This review highlights the importance of the As-induced generation of reactive oxygen species (ROS), as well as their damaging impacts on plants at biochemical, genetic, and molecular levels. The role of different enzymatic (superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (salicylic acid, proline, phytochelatins, glutathione, nitric oxide, and phosphorous) substances under As(III/V) stress have been delineated via conceptual models showing As translocation and toxicity pathways in plant species. Significantly, this review addresses the current, albeit partially understood, emerging aspects on (i) As-induced physiological, biochemical, and genotoxic mechanisms and responses in plants and (ii) the roles of different molecules in modulation of As-induced toxicities in plants. We also provide insight on some important research gaps that need to be filled to advance our scientific understanding in this area of research on As in soil-plant systems. PMID:29301332

Aspects on the Physiological and Biochemical Foundations of Neurocritical Care

PubMed Central

Nordström, Carl-Henrik; Koskinen, Lars-Owe; Olivecrona, Magnus

2017-01-01

Neurocritical care (NCC) is a branch of intensive care medicine characterized by specific physiological and biochemical monitoring techniques necessary for identifying cerebral adverse events and for evaluating specific therapies. Information is primarily obtained from physiological variables related to intracranial pressure (ICP) and cerebral blood flow (CBF) and from physiological and biochemical variables related to cerebral energy metabolism. Non-surgical therapies developed for treating increased ICP are based on knowledge regarding transport of water across the intact and injured blood–brain barrier (BBB) and the regulation of CBF. Brain volume is strictly controlled as the BBB permeability to crystalloids is very low restricting net transport of water across the capillary wall. Cerebral pressure autoregulation prevents changes in intracranial blood volume and intracapillary hydrostatic pressure at variations in arterial blood pressure. Information regarding cerebral oxidative metabolism is obtained from measurements of brain tissue oxygen tension (PbtO2) and biochemical data obtained from intracerebral microdialysis. As interstitial lactate/pyruvate (LP) ratio instantaneously reflects shifts in intracellular cytoplasmatic redox state, it is an important indicator of compromised cerebral oxidative metabolism. The combined information obtained from PbtO2, LP ratio, and the pattern of biochemical variables reveals whether impaired oxidative metabolism is due to insufficient perfusion (ischemia) or mitochondrial dysfunction. Intracerebral microdialysis and PbtO2 give information from a very small volume of tissue. Accordingly, clinical interpretation of the data must be based on information of the probe location in relation to focal brain damage. Attempts to evaluate global cerebral energy state from microdialysis of intraventricular fluid and from the LP ratio of the draining venous blood have recently been presented. To be of clinical relevance, the information from all monitoring techniques should be presented bedside online. Accordingly, in the future, the chemical variables obtained from microdialysis will probably be analyzed by biochemical sensors. PMID:28674514

Biochemical process of low level radioactive liquid simulation waste containing detergent

NASA Astrophysics Data System (ADS)

Kundari, Noor Anis; Putra, Sugili; Mukaromah, Umi

2015-12-01

Research of biochemical process of low level radioactive liquid waste containing detergent has been done. Thse organic liquid wastes are generated in nuclear facilities such as from laundry. The wastes that are cotegorized as hazard and poison materials are also radioactive. It must be treated properly by detoxification of the hazard and decontamination of the radionuclides to ensure that the disposal of the waste meets the requirement of standard quality of water. This research was intended to determine decontamination factor and separation efficiensies, its kinetics law, and to produce a supernatant that ensured the environmental quality standard. The radioactive element in the waste was thorium with activity of 5.10-5 Ci/m3. The radioactive liquid waste which were generated in simulation plant contains detergents that was further processed by aerobic biochemical process using SGB 103 bacteria in a batch reactor equipped with aerators. Two different concentration of samples were processed and analyzed for 212 hours and 183 hours respectively at a room temperature. The product of this process is a liquid phase called as supernatant and solid phase material called sludge. The chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solid (SS), and its alpha activity were analyzed. The results show that the decontamination factor and the separation efficiency of the lower concentration samples are higher compared to the samples with high concentration. Regarding the decontamination factor, the result for 212 hours processing of waste with detergent concentration of 1.496 g/L was 3.496 times, whereas at the detergent concentration of 0.748 g/L was 15.305 times for 183 hours processing. In case of the separation efficiency, the results for both samples were 71.396% and 93.465% respectively. The Bacterial growth kinetics equation follow Monod's model and the decreasing of COD and BOD were first order with the rate constant of 0.01 hour-1.

Biochemical process of low level radioactive liquid simulation waste containing detergent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kundari, Noor Anis, E-mail: nooranis@batan.go.id; Putra, Sugili; Mukaromah, Umi

Research of biochemical process of low level radioactive liquid waste containing detergent has been done. Thse organic liquid wastes are generated in nuclear facilities such as from laundry. The wastes that are cotegorized as hazard and poison materials are also radioactive. It must be treated properly by detoxification of the hazard and decontamination of the radionuclides to ensure that the disposal of the waste meets the requirement of standard quality of water. This research was intended to determine decontamination factor and separation efficiensies, its kinetics law, and to produce a supernatant that ensured the environmental quality standard. The radioactive elementmore » in the waste was thorium with activity of 5.10{sup −5} Ci/m{sup 3}. The radioactive liquid waste which were generated in simulation plant contains detergents that was further processed by aerobic biochemical process using SGB 103 bacteria in a batch reactor equipped with aerators. Two different concentration of samples were processed and analyzed for 212 hours and 183 hours respectively at a room temperature. The product of this process is a liquid phase called as supernatant and solid phase material called sludge. The chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solid (SS), and its alpha activity were analyzed. The results show that the decontamination factor and the separation efficiency of the lower concentration samples are higher compared to the samples with high concentration. Regarding the decontamination factor, the result for 212 hours processing of waste with detergent concentration of 1.496 g/L was 3.496 times, whereas at the detergent concentration of 0.748 g/L was 15.305 times for 183 hours processing. In case of the separation efficiency, the results for both samples were 71.396% and 93.465% respectively. The Bacterial growth kinetics equation follow Monod’s model and the decreasing of COD and BOD were first order with the rate constant of 0.01 hour{sup −1}.« less

Ionic Liquids Enabling Revolutionary Closed-Loop Life Support

NASA Technical Reports Server (NTRS)

Brown, Brittany R.; Abney, Morgan B.; Karr, Laurel; Stanley, Christine M.; Paley, Steve

2017-01-01

Minimizing resupply from Earth is essential for future long duration manned missions. The current oxygen recovery system aboard the International Space Station is capable of recovering approximately 50% of the oxygen from metabolic carbon dioxide. For long duration manned missions, a minimum of 75% oxygen recovery is targeted with a goal of greater than 90%. Theoretically, the Bosch process can recover 100% of oxygen, making it a promising technology for oxygen recovery for long duration missions. However, the Bosch process produces elemental carbon which ultimately fouls the catalyst. Once the catalyst performance is compromised, it must be replaced resulting in undesired resupply mass. Based on the performance of a Bosch system designed by NASA in the 1990's, a three year Martian mission would require approximately 1315 kg (2850 lbs) of catalyst resupply. It may be possible to eliminate catalyst resupply with a fully regenerable system using an Ionic Liquid (IL)-based Bosch system. In 2016, we reported the feasibility of using ILs to produce an iron catalyst on a copper substrate and to regenerate the iron catalyst by extracting the iron from the copper substrate and product carbon. Additionally, we described a basic system concept for an IL-based Bosch. Here we report the results of efforts to scale catalyst preparation, to scale catalyst regeneration, and to scale the carbon formation processing rate of a single reactor.

Ionic Liquids Enabling Revolutionary Closed-Loop Life Support

NASA Technical Reports Server (NTRS)

Brown, Brittany R.; Abney, Morgan B.; Karr, Laurel J.; Stanley, Christine M.; Donovan, Dave N.; Palsey, Mark S.

2017-01-01

Minimizing resupply from Earth is essential for future long duration manned missions. The current oxygen recovery system aboard the International Space Station is capable of recovering approximately 50% of the oxygen from metabolic carbon dioxide. For long duration manned missions, a minimum of 75% oxygen recovery is targeted with a goal of greater than 90%. Theoretically, the Bosch process can recover 100% of oxygen, making it a promising technology for oxygen recovery for long duration missions. However, the Bosch process produces elemental carbon which ultimately fouls the catalyst. Once the catalyst performance is compromised, it must be replaced resulting in undesired resupply mass. Based on the performance of a Bosch system designed by NASA in the 1990's, a three year Martian mission would require approximately 1315 kg (2850 lbs) of catalyst resupply. It may be possible to eliminate catalyst resupply with a fully regenerable system using an Ionic Liquid (IL)-based Bosch system. In 2016, we reported the feasibility of using ILs to produce an iron catalyst on a copper substrate and to regenerate the iron catalyst by extracting the iron from the copper substrate and product carbon. Additionally, we described a basic system concept for an IL-based Bosch. Here we report the results of efforts to scale catalyst preparation, catalyst regeneration, and to scale the carbon formation processing rate of a single reactor.

Molecular Probes: An Innovative Technology for Monitoring Membrane Processes

NASA Astrophysics Data System (ADS)

Santoro, Sergio

The ultimate objective of this study is to use molecular probes as an innovative and alternative technology contributing to the advance of membrane science by monitoring membrane processes in-situ, on-line and at sub-micron scale. An optical sensor for oxygen sensing was developed by the immobilization of tris (1,10-phenanthroline) ruthenium (II) (Ru(phen)3) in a dense polymeric membrane made of polystyrene (PS) or Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The emission of the probe was quenched by both the temperature and by the oxygen. Moreover, the oxygen sensitivity was affected by the oxygen permeability of the membrane. The evaluation of the oxygen concentration is prone to errors since the emission of a single probe depends on several parameters (i.e. optical path, source intensity). The correction of these artefacts was obtained by the immobilization of a second luminescent molecule non-sensitive to the oxygen, Coumarin. The potential of the luminescent ratiometric sensor for the non-invasive monitoring of oxygen in food packaging using polymeric films with different oxygen permeability was evaluated. Emphasis was given to the efficiency of the optical sensor for the on-line, in-situ and non invasive monitoring of the oxygen by comparing the experimental data with a model which takes into account the oxygen permeability of the packaging materials evaluated independently. A nano-thermometer based on silica nano-particles doped with Ru(phen)3 was developed. A systematic study shows how it is possible to control the properties of the nano-particles as well as their temperature sensitivity. The nano-thermometer was immobilized on a membrane surface by dip-coating providing information about the temperature on the membrane surface. Hydrophobic porous membrane made of Poly(vinylidene fluoride) was prepared via electrospinning and employed in a direct contact membrane distillation process. Using a designed membrane module and a membrane doped with Ru(phen)3 the on-line mapping of the temperature on the membrane's surface was evaluated. None None None None

High-Flow Nasal Cannula Oxygenation in Immunocompromised Patients With Acute Hypoxemic Respiratory Failure: A Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique Study.

PubMed

Lemiale, Virginie; Resche-Rigon, Matthieu; Mokart, Djamel; Pène, Frédéric; Argaud, Laurent; Mayaux, Julien; Guitton, Christophe; Rabbat, Antoine; Girault, Christophe; Kouatchet, Achille; Vincent, François; Bruneel, Fabrice; Nyunga, Martine; Seguin, Amélie; Klouche, Kada; Colin, Gwenahel; Kontar, Loay; Perez, Pierre; Meert, Anne-Pascale; Benoit, Dominique D; Papazian, Laurent; Demoule, Alexandre; Chevret, Sylvie; Azoulay, Elie

2017-03-01

In immunocompromised patients with acute respiratory failure, invasive mechanical ventilation remains associated with high mortality. Choosing the adequate oxygenation strategy is of the utmost importance in that setting. High-flow nasal oxygen has recently shown survival benefits in unselected patients with acute respiratory failure. The objective was to assess outcomes of immunocompromised patients with hypoxemic acute respiratory failure treated with high-flow nasal oxygen. We performed a post hoc analysis of a randomized controlled trial of noninvasive ventilation in critically ill immunocompromised patients with hypoxemic acute respiratory failure. Twenty-nine ICUs in France and Belgium. Critically ill immunocompromised patients with hypoxemic acute respiratory failure. A propensity score-based approach was used to assess the impact of high-flow nasal oxygen compared with standard oxygen on day 28 mortality. Among 374 patients included in the study, 353 met inclusion criteria. Underlying disease included mostly malignancies (n = 296; 84%). Acute respiratory failure etiologies were mostly pneumonia (n = 157; 44.4%) or opportunistic infection (n = 76; 21.5%). Noninvasive ventilation was administered to 180 patients (51%). Invasive mechanical ventilation was ultimately needed in 142 patients (40.2%). Day 28 mortality was 22.6% (80 deaths). Throughout the ICU stay, 127 patients (36%) received high-flow nasal oxygen whereas 226 patients received standard oxygen. Ninety patients in each group (high-flow nasal oxygen or standard oxygen) were matched according to the propensity score, including 91 of 180 (51%) who received noninvasive ventilation. High-flow nasal oxygen was neither associated with a lower intubation rate (hazard ratio, 0.42; 95% CI, 0.11-1.61; p = 0.2) nor day 28 mortality (hazard ratio, 0.80; 95% CI, 0.45-1.42; p = 0.45). In immunocompromised patients with hypoxemic acute respiratory failure, high-flow nasal oxygen when compared with standard oxygen did not reduce intubation or survival rates. However, these results could be due to low statistical power or unknown confounders associated with the subgroup analysis. A randomized trial is needed.

Modeling of Aircraft Deicing Fluid Induced Biochemical Oxygen Demand in Subsurface-Flow Constructed Treatment Wetlands

DTIC Science & Technology

2009-03-01

meters. The input and output control structures are modeled as sharp crested , rectangular weirs one meter in width. The elevation of the input weir is...manipulated by adjusting the width of both the input and output weirs and the crest height of the output weir . All of these adjustments were found to be...reduction of the weir crest height had an effect on the amount of storm water retained during low precipitation conditions, but not on the crest

Interplay between environmentally modulated feedback loops - hypoxia and circadian rhythms - two sides of the same coin?

PubMed

Depping, Reinhard; Oster, Henrik

2017-11-01

Sensing of environmental parameters is critically important for cells of metazoan organisms. Members of the superfamily of bHLH-PAS transcription factors, involved in oxygen sensing and circadian rhythm generation, are important players in such molecular pathways. The interplay between both networks includes a so far unknown factor, connecting PER2 (circadian clocks) to hypoxia sensing (HIF-1 α) to result in a more adapted state of homeostasis at the right time. © 2017 Federation of European Biochemical Societies.

Water-quality data from a sludge disposal test site, St. Petersburg, Florida, November 1973-July 1977

USGS Publications Warehouse

Fernandez, Mario

1978-01-01

From November 1973 to July 1977, water samples were collected from wells to identify background water-quality conditions and to determine the effects on ground-water quality by St. Petersburg 's sludge-disposal operation (sod farm). Specific conductance and pH were determined in the field. Samples were collected for laboratory determination of selected nitrogen and phosphorus species, sodium, potassium, calcium, magnesium, chloride, trace metals, chemical and biochemical oxygen demand, and coliforms. (Woodard-USGS)

AG-348 enhances pyruvate kinase activity in red blood cells from patients with pyruvate kinase deficiency

PubMed Central

Hixon, Jeff; Kosinski, Penelope A.; Cianchetta, Giovanni; Histen, Gavin; Chen, Yue; Hill, Collin; Gross, Stefan; Si, Yaguang; Johnson, Kendall; DeLaBarre, Byron; Luo, Zhiyong; Gu, Zhiwei; Yao, Gui; Tang, Huachun; Fang, Cheng; Xu, Yingxia; Lv, Xiaobing; Biller, Scott; Su, Shin-San Michael; Yang, Hua; Popovici-Muller, Janeta; Salituro, Francesco; Silverman, Lee; Dang, Lenny

2017-01-01

Pyruvate kinase (PK) deficiency is a rare genetic disease that causes chronic hemolytic anemia. There are currently no targeted therapies for PK deficiency. Here, we describe the identification and characterization of AG-348, an allosteric activator of PK that is currently in clinical trials for the treatment of PK deficiency. We demonstrate that AG-348 can increase the activity of wild-type and mutant PK enzymes in biochemical assays and in patient red blood cells treated ex vivo. These data illustrate the potential for AG-348 to restore the glycolytic pathway activity in patients with PK deficiency and ultimately lead to clinical benefit. PMID:28760888

Spatio-temporal variability of hydro-chemical characteristics of coastal waters of Gulf of Mannar Marine Biosphere Reserve (GoMMBR), South India

NASA Astrophysics Data System (ADS)

Kathiravan, K.; Natesan, Usha; Vishnunath, R.

2017-03-01

The intention of this study was to appraise the spatial and temporal variations in the physico-chemical parameters of coastal waters of Rameswaram Island, Gulf of Mannar Marine Biosphere Reserve, south India, using multivariate statistical techniques, such as cluster analysis, factor analysis and principal component analysis. Spatio-temporal variations among the physico-chemical parameters are observed in the coastal waters of Gulf of Mannar, especially during northeast and post monsoon seasons. It is inferred that the high loadings of pH, temperature, suspended particulate matter, salinity, dissolved oxygen, biochemical oxygen demand, chlorophyll a, nutrient species of nitrogen and phosphorus strongly determine the discrimination of coastal water quality. Results highlight the important role of monsoonal variations to determine the coastal water quality around Rameswaram Island.

Green Walls as an Approach in Grey Water Treatment

NASA Astrophysics Data System (ADS)

Rysulova, Martina; Kaposztasova, Daniela; Vranayova, Zuzana

2017-10-01

Grey water contributes significantly to waste water parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total phosphorus (Ptotal), total nitrogen (Ntotal), ammonium, boron, metals, salts, surfactants, synthetic chemicals, oils and greases, xenobiotic substances and microorganisms. Concentration of these pollutants and the water quality highlights the importance of treatment process in grey water systems. Treatment technologies operating under low energy and maintenance are usually preferred, since they are more cost effective for users. Treatment technologies based on natural processes represent an example of such technology including vegetated wall. Main aim of this paper is to introduce the proposal of vegetated wall managing grey water and brief characteristic of proposed system. Is expected that prepared experiment will establish the purifying ability and the potential of green wall application as an efficient treatment technology.

A combined electrocoagulation-sorption process applied to mixed industrial wastewater.

PubMed

Linares-Hernández, Ivonne; Barrera-Díaz, Carlos; Roa-Morales, Gabriela; Bilyeu, Bryan; Ureña-Núñez, Fernando

2007-06-01

The removal of organic pollutants from a highly complex industrial wastewater by a aluminium electrocoagulation process coupled with biosorption was evaluated. Under optimal conditions of pH 8 and 45.45 Am(-2) current density, the electrochemical method yields a very effective reduction of all organic pollutants, this reduction was enhanced when the biosorption treatment was applied as a polishing step. Treatment reduced chemical oxygen demand (COD) by 84%, biochemical oxygen demand (BOD(5)) by 78%, color by 97%, turbidity by 98% and fecal coliforms by 99%. The chemical species formed in aqueous solution were determined. The initial and final pollutant levels in the wastewater were monitored using UV-vis spectrometry and cyclic voltammetry. Finally, the morphology and elemental composition of the biosorbent was characterized with scanning electron microscopy (SEM) and energy dispersion spectra (EDS).

Mitochondrial role in cell aging

NASA Technical Reports Server (NTRS)

Miquel, J.; Fleming, J.; Economos, A. C.; Johnson, J. E., Jr.

1980-01-01

The experimental studies on the mitochondria of insect and mammalian cells are examined with a view to an analysis of intrinsic mitochondrial senescence, and its relation to the age-related changes in other cell organelles. The fine structural and biochemical data support the concept that the mitochondria of fixed postmitotic cells may be the site of intrinsic aging because of the attack by free radicals and lipid peroxides originating in the organelles as a by-product of oxygen reduction during respiration. Although the cells have numerous mechanisms for counteracting lipid peroxidation injury, there is a slippage in the antioxidant protection. Intrinsic mitochondrial aging could thus be considered as a specific manifestation of oxygen toxicity. It is proposed that free radical injury renders an increasing number of the mitochondria unable to divide, probably because of damage to the lipids of the inner membrane and to mitochondrial DNA.

Influence of vegetation and gravel mesh on the tertiary treatment of wastewater from a cosmetics industry.

PubMed

Vlyssides, Apostolos G; Mai, Sofia T H; Barampouti, Elli Maria P; Loukakis, Haralampos N

2009-07-01

To estimate the influence of gravel mesh (fine and coarse) and vegetation (Phragmites and Arundo) on the efficiency of a reed bed, a pilot plant was included after the wastewater treatment plant of a cosmetic industry treatment system according to a 22 factorial experimental design. The maximum biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total phosphorous (TP) reduction was observed in the reactor, where Phragmites and fine gravel were used. In the reactor with Phragmites and coarse gravel, the maximum total Kjeldahl nitrogen (TKN) and total suspended solids (TSS) reduction was observed. The maximum total solids reduction was measured in the reed bed, which was filled with Arundo and coarse gravel. Conclusively, the treatment of a cosmetic industry's wastewater by reed beds as a tertiary treatment method is quite effective.

Modeling, simulation, and control of an extraterrestrial oxygen production plant

NASA Technical Reports Server (NTRS)

Schooley, L.; Cellier, F.; Zeigler, B.; Doser, A.; Farrenkopf, G.

1991-01-01

The immediate objective is the development of a new methodology for simulation of process plants used to produce oxygen and/or other useful materials from local planetary resources. Computer communication, artificial intelligence, smart sensors, and distributed control algorithms are being developed and implemented so that the simulation or an actual plant can be controlled from a remote location. The ultimate result of this research will provide the capability for teleoperation of such process plants which may be located on Mars, Luna, an asteroid, or other objects in space. A very useful near-term result will be the creation of an interactive design tool, which can be used to create and optimize the process/plant design and the control strategy. This will also provide a vivid, graphic demonstration mechanism to convey the results of other researchers to the sponsor.

Linking microbial community structure to membrane biofouling associated with varying dissolved oxygen concentrations.

PubMed

Gao, Da-wen; Fu, Yuan; Tao, Yu; Li, Xin-xin; Xing, Min; Gao, Xiu-hong; Ren, Nan-qi

2011-05-01

In order to elucidate how dissolved oxygen (DO) concentration influenced the generation of extracellular polymeric substance (EPS) and soluble microbial products (SMP) in mixed liquor and biocake, 16S rDNA fingerprinting analyses were performed to investigate the variation of the microbial community in an aerobic membrane bioreactor (MBR). The function of microbial community structure was proved to be ultimately responsible for biofouling. Obvious microbial community succession from the subphylum of Betaproteobacteria to Deltaproteobacteria was observed in biocake. High concentration of EPS in biocake under the low DO concentration (0.5 mg L(-1)) caused severe biofouling. The correlation coefficient of membrane fouling rate with EPS content in biocake (0.9941-0.9964) was much higher than that in mixed liquor (0.6689-0.8004). Copyright © 2011 Elsevier Ltd. All rights reserved.

Flow-induced Vibration of SSME Main Injector Liquid-oxygen Posts

NASA Technical Reports Server (NTRS)

Chen, S. S.; Jendrzejczyk, J. A.; Wambsganss, M. W.

1985-01-01

The liquid-oxygen (LOX) posts are exposed to hot hydrogen flowing over the tubes on its way to the combustion chamber. Fatigue cracking of some LOX posts was observed after test firing of the SSMEs. A current design modification consists of attaching impingement shields to the LOX posts in the outer row. The modification improved the vibration/fatigue problem of the LOX posts, but resulted in an increased pressure drop that ultimately shortened the life expectancy of other components. A fundamental study of vibration of the LOX posts was initiated to understand the flow-induced vibration problem and to develop techniques to avoid detrimental vibrational effects with the overall objective of improving engine life. This effort, including an assessment of the problem, scoping calculation and experiment, and a work plan for an integrated theoretical/experimental study of the problem is summarized.

Concentration Effects of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Activity for Three Platinum Catalysts

DOE PAGES

Christ, J. M.; Neyerlin, K. C.; Richards, R.; ...

2014-10-04

A rotating disk electrode (RDE) along with cyclic voltammetry (CV) and linear sweep voltammetry (LSV), were used to investigate the impact of two model compounds representing degradation products of Nafion and 3M perfluorinated sulfonic acid membranes on the electrochemical surface area (ECA) and oxygen reduction reaction (ORR) activity of polycrystalline Pt, nano-structured thin film (NSTF) Pt (3M), and Pt/Vulcan carbon (Pt/Vu) (TKK) electrodes. ORR kinetic currents (measured at 0.9 V and transport corrected) were found to decrease linearly with the log of concentration for both model compounds on all Pt surfaces studied. Ultimately, model compound adsorption effects on ECA weremore » more abstruse due to competitive organic anion adsorption on Pt surfaces superimposing with the hydrogen underpotential deposition (HUPD) region.« less

Water Quality Characteristics of Sembrong Dam Reservoir, Johor, Malaysia

NASA Astrophysics Data System (ADS)

Mohd-Asharuddin, S.; Zayadi, N.; Rasit, W.; Othman, N.

2016-07-01

A study of water quality and heavy metal content in Sembrong Dam water was conducted from April - August 2015. A total of 12 water quality parameters and 6 heavy metals were measured and classified based on the Interim National Water Quality Standard of Malaysia (INWQS). The measured and analyzed parameter variables were divided into three main categories which include physical, chemical and heavy metal contents. Physical and chemical parameter variables were temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), turbidity, pH, nitrate, phosphate, ammonium, conductivity and salinity. The heavy metals measured were copper (Cu), lead (Pb), aluminium (Al), chromium (Cr), ferum (Fe) and zinc (Zn). According to INWQS, the water salinity, conductivity, BOD, TSS and nitrate level fall under Class I, while the Ph, DO and turbidity lie under Class IIA. Furthermore, values of COD and ammonium were classified under Class III. The result also indicates that the Sembrong Dam water are not polluted with heavy metals since all heavy metal readings recorded were falls far below Class I.

The quality of raw water for drinking water unit in Jakarta-Indonesia

NASA Astrophysics Data System (ADS)

Sidabutar, Noni Valeria; Hartono, Djoko M.; Soesilo, Tri Edhi Budhi; Hutapea, Reynold C.

2017-03-01

Water problems, i.e quality, quantity, continuity of clean water faced by the mostly urban area. Jakarta also faces similar issues, because the needs of society higher than the number of water fulfilled by the government. Moreover, Jakarta's water quality does not meet the standard set by the Government and heavily polluted by anthropogenic activities along its rivers. This research employs a quantitative research approach with the mix-method. It examines the raw water quality status for drinking water in West Tarum Canalin 2011-2015. The research results show water quality with this research, using water quality of with the water categorized as heavily-polluted category based on the Ministry of Environment's Decree No 115/2003 regarding the Guidelines for Determination of Water Quality Status. This present research also shown the water quality (parameters pH, temperature, Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD)) from Jatiluhur Dam to the intake drinking water unit. In thirteen points of sampling also, the results obtained the parameters DO, COD, and BOD are fluctuating and exceed the standard.

Data bank of optical properties of biological tissue and blood in the visible and near infrared spectral region

NASA Astrophysics Data System (ADS)

Khairullina, Alphiya Y.; Bui, Lilia; Oleinik, Tatiana V.; Artishevsky, Nelli; Prigoun, Natalia; Sevkovsky, Jakov; Mokhort, Tatiana

1996-12-01

The data bank contains optical, ordinary biochemical and biophysical information on 120 venous blood samples of donors, healthy persons, patients with high pathology, 60 tissue samples. The optical parameters include diffuse reflection R((lambda) ) and transmission T((lambda) ) coefficients for optically thick layers, the absorption K((lambda) ) and extinction (epsilon) ((lambda) ) spectra, oxygenation degree CO2, parameter p determined by sizes and shapes of cells and their aggregates, refractive index of a disperse phase relative to surrounding media, and cooperative effects at high relative concentration. The peculiarities in absorption K((lambda) spectra are connected with different pathologies. It is shown from K((lambda) ) that the grade of pathology connected with the concentration of hemoglobin and mithohondrion together with oxygenation degree of blood and tissues, with the pathological hemoglobin's forms and its decomposition products of different levels. Parameter p is an important diagnostic parameter. We consider that it is necessary to include the oxygenation degree and erythrocyte's aggregation parameter to extend the range of common diagnostic parameters of blood by the first rota.

Monitoring and assessment of water quality of Tasik Cempaka, Bangi

NASA Astrophysics Data System (ADS)

Sabri, Nurul Ain Syahirah Mohamad; Abdullah, Md Pauzi; Mat, Sohif

2014-09-01

A study was carried out to determine the status of water quality of Tasik Cempaka which is a part of Sg. Air Itam, located near the Bangi industrial area. The study was carried out for eight months from May and to December 2013. Eight sampling stations were selected from upstream to downstream of Sg. Air Itam which represent the entire body of the lake water. There are 8 parameters measured and Water Quality Indices (WQI) was calculated and classified according to the National Water Quality Standard (NWQS). The physical and chemical parameters were temperature, pH, conductivity, dissolve oxygen (DO), total suspended solid (TSS), ammoniacal nitrogen (AN), chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Among parameters that are affected by pollution is AN, COD and BOD. Classification by WQI shows that the average for all sampling was 54 (dry) and 52 (wet). Both are of class III according to National Water Quality Standard (NWQS) indicating slightly polluted. This is mainly due to drainage from Bangi Golf Resort and Bangi-Putrajaya Hotel. Other factors are activities around Sg. Air Itam such as municipal activities, settlements and manufacturing industries.

Turtle anoxia tolerance: Biochemistry and gene regulation.

PubMed

Krivoruchko, Anastasia; Storey, Kenneth B

2015-06-01

While oxygen limitation can be extremely damaging for many animals, some vertebrates have perfected anaerobic survival. Freshwater turtles belonging to the Trachemys and Chrysemys genera, for example, can survive many weeks without oxygen, and as such are commonly used as model animals for vertebrate anoxia tolerance. In the present review we discuss the recent advances made in understanding the biochemical and molecular nature of natural anoxia tolerance of freshwater turtles. Research in recent years has shown that activation of several important pathways occurs in response to anoxia in turtles, including those that function in the stress response, cell cycle arrest, inhibition of gene expression and metabolism. These likely contribute to anoxia tolerance in turtle tissues by minimizing cell damage in response to anoxia, as well as facilitating metabolic rate depression. The research discussed in the present review contributes to the understanding of how freshwater turtles can survive without oxygen for prolonged periods of time. This could also improve understanding of the molecular nature of hypoxic/ischemic injuries in mammalian tissues and suggest potential ways to avoid these. Copyright © 2015 Elsevier B.V. All rights reserved.

Childhood polycythemias/erythrocytoses: classification, diagnosis, clinical presentation, and treatment.

PubMed

Cario, H

2005-03-01

Polycythemias or erythrocytoses in childhood and adolescence are very rare. Systematic data on the clinical presentation and laboratory evaluations as well as on treatment regimens are sparse. The diagnostic program in absolute erythrocytosis includes extensive clinical, hematological, biochemical, and molecular biological examinations which should be applied following a stepwise algorithm. Absolute erythrocytoses are usually subdivided into primary and secondary forms. Primary erythrocytosis is a condition in which the erythropoietic compartment is expanding independently of extrinsic influences or by responding inadequately to them. Primary erythrocytoses include primary familial and congenital polycythemia (PFCP) due to mutations of the erythropoietin (Epo) receptor gene and the myeloproliferative disorder polycythemia vera. Secondary erythrocytoses are driven by hormonal factors (predominantly by Epo) extrinsic to the erythroid compartment. The increased Epo secretion may represent either a physiologic response to tissue hypoxia, an abnormal autonomous Epo production, or a dysregulation of the oxygen-dependent Epo synthesis. Congenital secondary erythrocytoses are caused, e.g., by hemoglobin variants with increased oxygen affinity, by 2,3-bisphosphoglycerate deficiency, or by mutations in the von Hippel-Lindau gene associated with a disturbed oxygen-dependent regulation of Epo synthesis.

A Comprehensive Review on Water Quality Parameters Estimation Using Remote Sensing Techniques.

PubMed

Gholizadeh, Mohammad Haji; Melesse, Assefa M; Reddi, Lakshmi

2016-08-16

Remotely sensed data can reinforce the abilities of water resources researchers and decision makers to monitor waterbodies more effectively. Remote sensing techniques have been widely used to measure the qualitative parameters of waterbodies (i.e., suspended sediments, colored dissolved organic matter (CDOM), chlorophyll-a, and pollutants). A large number of different sensors on board various satellites and other platforms, such as airplanes, are currently used to measure the amount of radiation at different wavelengths reflected from the water's surface. In this review paper, various properties (spectral, spatial and temporal, etc.) of the more commonly employed spaceborne and airborne sensors are tabulated to be used as a sensor selection guide. Furthermore, this paper investigates the commonly used approaches and sensors employed in evaluating and quantifying the eleven water quality parameters. The parameters include: chlorophyll-a (chl-a), colored dissolved organic matters (CDOM), Secchi disk depth (SDD), turbidity, total suspended sediments (TSS), water temperature (WT), total phosphorus (TP), sea surface salinity (SSS), dissolved oxygen (DO), biochemical oxygen demand (BOD) and chemical oxygen demand (COD).

Role of novel delivery systems in developing topical antioxidants as therapeutics to combat photoageing.

PubMed

Kaur, Indu P; Kapila, Meenakshi; Agrawal, Rumjhum

2007-12-01

Ageing proceeds by highly complicated biochemical processes, in which the involvement of the reactive oxygen species (ROS) and free radicals has been implicated. Reactive oxygen species are dramatically enhanced by exposure to the ultraviolet radiation. Free radical scavengers and antioxidants can thus provide a long-term protection against these changes. Currently, dermaceutical and cosmetic industry is growing immensely with its main focus on packaging the active into a suitable/novel delivery system. This not only enhances the customer acceptance but offers better targeting to the upper skin layer, with faster onset, at a lower concentration of the active. Later also counter toxic or adverse effects observed with large doses especially when administered orally. Several of the antioxidant molecules are labile to degradation in the presence of oxygen, water and light, hence it becomes all the more appropriate to use a delivery system which will augment their stability and hence enhance the performance. In the present review, we focus on the pioneering research on novel delivery systems which can promote the therapeutic value of antioxidants for combating UV-induced photoageing.

Water quality management using statistical analysis and time-series prediction model

NASA Astrophysics Data System (ADS)

Parmar, Kulwinder Singh; Bhardwaj, Rashmi

2014-12-01

This paper deals with water quality management using statistical analysis and time-series prediction model. The monthly variation of water quality standards has been used to compare statistical mean, median, mode, standard deviation, kurtosis, skewness, coefficient of variation at Yamuna River. Model validated using R-squared, root mean square error, mean absolute percentage error, maximum absolute percentage error, mean absolute error, maximum absolute error, normalized Bayesian information criterion, Ljung-Box analysis, predicted value and confidence limits. Using auto regressive integrated moving average model, future water quality parameters values have been estimated. It is observed that predictive model is useful at 95 % confidence limits and curve is platykurtic for potential of hydrogen (pH), free ammonia, total Kjeldahl nitrogen, dissolved oxygen, water temperature (WT); leptokurtic for chemical oxygen demand, biochemical oxygen demand. Also, it is observed that predicted series is close to the original series which provides a perfect fit. All parameters except pH and WT cross the prescribed limits of the World Health Organization /United States Environmental Protection Agency, and thus water is not fit for drinking, agriculture and industrial use.

A unique iron-sulfur cluster is crucial for oxygen tolerance of a [NiFe]-hydrogenase.

PubMed

Goris, Tobias; Wait, Annemarie F; Saggu, Miguel; Fritsch, Johannes; Heidary, Nina; Stein, Matthias; Zebger, Ingo; Lendzian, Friedhelm; Armstrong, Fraser A; Friedrich, Bärbel; Lenz, Oliver

2011-05-01

Hydrogenases are essential for H(2) cycling in microbial metabolism and serve as valuable blueprints for H(2)-based biotechnological applications. However, most hydrogenases are extremely oxygen sensitive and prone to inactivation by even traces of O(2). The O(2)-tolerant membrane-bound [NiFe]-hydrogenase of Ralstonia eutropha H16 is one of the few examples that can perform H(2) uptake in the presence of ambient O(2). Here we show that O(2) tolerance is crucially related to a modification of the internal electron-transfer chain. The iron-sulfur cluster proximal to the active site is surrounded by six instead of four conserved coordinating cysteines. Removal of the two additional cysteines alters the electronic structure of the proximal iron-sulfur cluster and renders the catalytic activity sensitive to O(2) as shown by physiological, biochemical, spectroscopic and electrochemical studies. The data indicate that the mechanism of O(2) tolerance relies on the reductive removal of oxygenic species guided by the unique architecture of the electron relay rather than a restricted access of O(2) to the active site.

A Comprehensive Review on Water Quality Parameters Estimation Using Remote Sensing Techniques

PubMed Central

Gholizadeh, Mohammad Haji; Melesse, Assefa M.; Reddi, Lakshmi

2016-01-01

Remotely sensed data can reinforce the abilities of water resources researchers and decision makers to monitor waterbodies more effectively. Remote sensing techniques have been widely used to measure the qualitative parameters of waterbodies (i.e., suspended sediments, colored dissolved organic matter (CDOM), chlorophyll-a, and pollutants). A large number of different sensors on board various satellites and other platforms, such as airplanes, are currently used to measure the amount of radiation at different wavelengths reflected from the water’s surface. In this review paper, various properties (spectral, spatial and temporal, etc.) of the more commonly employed spaceborne and airborne sensors are tabulated to be used as a sensor selection guide. Furthermore, this paper investigates the commonly used approaches and sensors employed in evaluating and quantifying the eleven water quality parameters. The parameters include: chlorophyll-a (chl-a), colored dissolved organic matters (CDOM), Secchi disk depth (SDD), turbidity, total suspended sediments (TSS), water temperature (WT), total phosphorus (TP), sea surface salinity (SSS), dissolved oxygen (DO), biochemical oxygen demand (BOD) and chemical oxygen demand (COD). PMID:27537896

Comparative analysis of the electrostatic potentials of some structural analogues of 2,3,7,8-tetrachlorodibenzo-p-dioxin and of related aromatic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, J.S.; Evans, P.; Politzer, P.

1990-01-01

An ab initio STO-5G computational analysis of the electrostatic potentials of four structural analogs of the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and four related aromatic systems (benzo(a)pyrene, benz(a)anthracene and two isomeric benzoflavones) was carried out. The systems, to varying degrees, induce aryl hydrocarbon hydroxylase activity and are believed to interact with the same cytosolic receptor in initiating their biochemical responses. It was found that a high degree of activity appears to require negative potentials that are non-overlapping above all or most of the lateral regions, with an observed optimum range of magnitudes. In systems with central oxygens, it is required thatmore » the negative oxygen potentials be small and weak; however, oxygen negative regions in the molecule are not necessary for high activity. The observed differences between the potential patterns of the four aromatic systems and those of TCDD and its active analogs may reflect an inherent dissimilarity in the nature of their interactions with the cytosolic receptor.« less

Reconnaissance of water-quality characteristics of streams in the City of Charlotte and Mecklenburg County, North Carolina

USGS Publications Warehouse

Eddins, W.H.; Crawford, J.K.

1984-01-01

In 1979-81, water samples were collected from 119 sites on streams throughout the City of Charlotte and Mecklenburg County, North Carolina, and were analyzed for specific conductance, dissolved chloride, hardness, pH, total alkalinity, total phosphorus, trace elements, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, silver, and zinc and biological measures including dissolved oxygen, biochemical oxygen demand, fecal coliform bacteria, and fecal streptococcus bacteria. Sampling was conducted during both low flow (base flow) and high flow. Several water-quality measures including pH, total arsenic, total cadmium, total chromium, total copper, total iron, total lead, total manganese, total mercury, total silver, total zinc, dissolved oxygen, and fecal coliform bacteria at times exceeded North Carolina water-quality standards in various streams. Runoff from non-point sources appears to contribute more to the deterioration of streams in Charlotte and Mecklenburg County than point-source effluents. Urban and industrial areas contribute various trace elements. Residential and rural areas and municipal waste-water treatment plants contribute high amounts of phosphorus.

Measuring the retina optical properties using a structured illumination imaging system

NASA Astrophysics Data System (ADS)

Basiri, A.; Nguyen, T. A.; Ibrahim, M.; Nguyen, Q. D.; Ramella-Roman, Jessica C.

2011-03-01

Patients with diabetic retinopathy (DR) may experience a reduction in retinal oxygen saturation (SO2). Close monitoring with a fundus ophthalmoscope can help in the prediction of the progression of disease. In this paper we present a noninvasive instrument based on structured illumination aimed at measuring the retina optical properties including oxygen saturation. The instrument uses two wavelngths one in the NIR and one visible, a fast acquisition camera, and a splitter system that allows for contemporaneous collection of images at two different wavelengths. This scheme greatly reduces eye movement artifacts. Structured illumination was achieved in two different ways, firstly several binary illumination masks fabricated using laser micro-machining were used, a near-sinusoidal projection pattern is ultimately achieved at the image plane by appropriate positioning of the binary masks. Secondarily a sinusoidal pattern printed on a thin plastic sheet was positioned at image plane of a fundus ophthalmoscope. The system was calibrated using optical phantoms of known optical properties as well as an eye phantom that included a 150μm capillary vessel containing different concentrations of oxygenated and deoxygenated hemoglobin.

Uranium Stable Isotopes: A Proxy For Productivity Or Ocean Oxygenation?

NASA Astrophysics Data System (ADS)

Severmann, S.

2015-12-01

Uranium elemental abundances in sediments have traditionally been used to reconstruct primary productivity and carbon flux in the ocean. 238U/235U isotope compositions, in contrast, are currently understood to reflect the extent of bottom water anoxia in the ocean. A review of our current understanding of authigenic U enrichment mechanism into reducing sediments suggests that a revision of this interpretation is warranted. Specifically, the current interpretation of U isotope effects in suboxic vs. anoxic deposits has not taken into account the well-documented linear relationship with organic C burial rates. Although organic C rain rates (i.e., surface productivity) and bottom water oxygenation are clearly related, distinction between these two environmental controls is conceptually important as it relates to the mechanism of enhanced C burial and ultimately the strength of the biological pump. Here we will review new and existing data to test the hypothesis that the isotope composition of authigenic U in reducing sediments are best described by their relationship with parameters related to organic carbon delivery and burial, rather than bottom water oxygen concentration.

Hypoxic Niche-Mediated Regeneration of Hematopoiesis in the Engraftment Window Is Dominantly Affected by Oxygen Tension in the Milieu

PubMed Central

Moirangthem, Ranjita Devi; Singh, Shweta; Adsul, Ashwini; Jalnapurkar, Sapana; Limaye, Lalita

2015-01-01

The bone marrow (BM) microenvironment or the hematopoietic stem cell (HSC) niche is normally hypoxic, which maintains HSC quiescence. Paradoxically, transplanted HSCs rapidly proliferate in this niche. Pretransplant myelosuppression results in a substantial rise in oxygen levels in the marrow microenvironment due to reduced cellularity and consequent low oxygen consumption. Therefore, it may be construed that the rapid proliferation of the engrafted HSCs in the BM niche is facilitated by the transiently elevated oxygen tension in this milieu during the “engraftment window.” To determine whether oxygen tension dominantly affects the regeneration of hematopoiesis in the BM niche, we created an “oxygen-independent hypoxic niche” by treating BM-derived mesenchymal stromal cells (BMSCs) with a hypoxia-mimetic compound, cobalt chloride (CoCl2) and cocultured them with BM-derived HSC-enriched cells under normoxic conditions (HSCs; CoCl2-cocultures). Cocultures with untreated BMSCs incubated under normoxia (control- cocultures) or hypoxia (1% O2; hypoxic-cocultures) were used as comparators. Biochemical analyses showed that though, both CoCl2 and hypoxia evoked comparable signals in the BMSCs, the regeneration of hematopoiesis in their respective cocultures was radically different. The CoCl2-BMSCs supported robust hematopoiesis, while the hypoxic-BMSCs exerted strong inhibition. The hematopoiesis-supportive ability of CoCl2-BMSCs was abrogated if the CoCl2-cocultures were incubated under hypoxia, demonstrating that the prevalent oxygen tension in the milieu dominantly affects the outcome of the HSC-BM niche interactions. Our data suggest that pharmacologically delaying the reestablishment of hypoxia in the BM may boost post-transplant regeneration of hematopoiesis. PMID:26107807

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Sand Creek, Decatur County, Indiana

USGS Publications Warehouse

Wilber, William G.; Crawford, Charles G.; Peters, James G.

1979-01-01

A digital model calibrated to conditions in Sand Creek near Greensburg, Ind., was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The only point-source waste load affecting Sand Creek in the vicinity of Greensburg is the Greensburg wastewater-treatment facility. Non-point, unrecorded waste loads seemed to be significant during three water-quality surveys done by the Indiana State Board of Health. Natural streamflow in Sand Creek during the summer and annual 7-day, 10-year low flow is zero so no benefit from dilution is provided. Effluent ammonia-nitrogen concentrations from the Greensburg wastewater-treatment facility will not meet Indiana water-quality standards during summer and winter low flows. To meet the water-quality standard the wastewater-effluent would be limited to a maximum total ammonia-nitrogen concentration of 2.5 mg/l for summer months (June through August) and 4.0 mg/l for winter months (November through March). Model simulations indicate that benthic-oxygen demand, nitrification, and the dissolved-oxygen concentration of the wastewater effluent are the most significant factors affecting the in-stream dissolved-oxygen concentration during summer low flows. The model predicts that with a benthic-oxygen demand of 1.5 grams per square meter per day at 20C the stream has no additional waste-load assimilative capacity. Present carbonaceous biochemical-oxygen demand loads from the Greensburg wastewater-treatment facility will not result in violations of the in-stream dissolved-oxygen standard (5 mg/l) during winter low flows. (Kosco-USGS)

Developing a Customized Perfusion Bioreactor Prototype with Controlled Positional Variability in Oxygen Partial Pressure for Bone and Cartilage Tissue Engineering.

PubMed

Lee, Poh Soo; Eckert, Hagen; Hess, Ricarda; Gelinsky, Michael; Rancourt, Derrick; Krawetz, Roman; Cuniberti, Gianaurelio; Scharnweber, Dieter

2017-05-01

Skeletal development is a multistep process that involves the complex interplay of multiple cell types at different stages of development. Besides biochemical and physical cues, oxygen tension also plays a pivotal role in influencing cell fate during skeletal development. At physiological conditions, bone cells generally reside in a relatively oxygenated environment whereas chondrocytes reside in a hypoxic environment. However, it is technically challenging to achieve such defined, yet diverse oxygen distribution on traditional in vitro cultivation platforms. Instead, engineered osteochondral constructs are commonly cultivated in a homogeneous, stable environment. In this study, we describe a customized perfusion bioreactor having stable positional variability in oxygen tension at defined regions. Further, engineered collagen constructs were coaxed into adopting the shape and dimensions of defined cultivation platforms that were precasted in 1.5% agarose bedding. After cultivating murine embryonic stem cells that were embedded in collagen constructs for 50 days, mineralized constructs of specific dimensions and a stable structural integrity were achieved. The end-products, specifically constructs cultivated without chondroitin sulfate A (CSA), showed a significant increase in mechanical stiffness compared with their initial gel-like constructs. More importantly, the localization of osteochondral cell types was specific and corresponded to the oxygen tension gradient generated in the bioreactor. In addition, CSA in complementary with low oxygen tension was also found to be a potent inducer of chondrogenesis in this system. In summary, we have demonstrated a customized perfusion bioreactor prototype that is capable of generating a more dynamic, yet specific cultivation environment that could support propagation of multiple osteochondral lineages within a single engineered construct in vitro. Our system opens up new possibilities for in vitro research on human skeletal development.

Simulation of oil bioremediation in a tidally influenced beach: Spatiotemporal evolution of nutrient and dissolved oxygen

NASA Astrophysics Data System (ADS)

Geng, Xiaolong; Pan, Zhong; Boufadel, Michel C.; Ozgokmen, Tamay; Lee, Kenneth; Zhao, Lin

2016-04-01

Numerical experiments of oil bioremediation of tidally influenced beach were simulated using the model BIOMARUN. Nutrient and dissolved oxygen were assumed present in a solution applied on the exposed beach face, and the concentration of these amendments was tracked throughout the beach for up to 6 months. It was found that, in comparison to natural attenuation, bioremediation increased the removal efficiency by 76% and 65% for alkanes and aromatics, respectively. Increasing the nutrient concentration in the applied solution did not always enhance biodegradation as oxygen became limiting even when the beach was originally oxygen-rich. Therefore, replenishment of oxygen to oil-contaminated zone was also essential. Stimulation of oil biodegradation was more evident in the upper and midintertidal zone of the beach, and less in the lower intertidal zone. This was due to reduced nutrient and oxygen replenishment, as very little of the amendment solution reached that zone. It was found that under continual application, most of the oil biodegraded within 2 months, while it persisted for 6 months under natural conditions. While the difference in duration suggests minimal long-term effects, there are situations where the beach would need to be cleaned for major ecological functions, such as temporary nesting or feeding for migratory birds. Biochemical retention time map (BRTM) showed that the duration of solution application was dependent upon the stimulated oil biodegradation rate. By contrast, the application rate of the amendment solution was dependent upon the subsurface extent of the oil-contaminated zone. Delivery of nutrient and oxygen into coastal beach involved complex interaction among amendment solution, groundwater, and seawater. Therefore, approaches that ignore the hydrodynamics due to tide are unlikely to provide the optimal solutions for shoreline bioremediation.

Environmental Genomic Analysis of Stratified Microbial Communities and Climate Active Gases in the Subarctic Pacific Oxygen Minimum Zone

NASA Astrophysics Data System (ADS)

Wright, J.; Hallam, S.; Merzouk, A.; Tortell, P.

2008-12-01

Oxygen minimum zones (OMZs) are areas of low dissolved oxygen concentrations that play a major role in biogeochemical cycling within the world's oceans. They are major sinks for nitrogen and sources for the greenhouse gases carbon dioxide and nitrous oxide. Therefore, microbial mediated biological activity associated with these systems directly impacts ocean productivity and global climate balance. There is increasing evidence that ocean warming trends will decrease dissolved oxygen concentrations within the coastal and interior regions of the subarctic Pacific, causing an expansion of the hypoxic boundary layer. This expansion will have a direct effect on coastal benthic ecosystems and the productivity of marine fisheries due to habitat loss and changes in nutrient cycling. In order to understand the potential implications of these transitions, we are performing environmental genomic analyses of indigenous microbial communities found in coastal and open ocean OMZs in the subarctic Pacific Ocean in relation to dissolved gas and nutrient concentrations. In addition to identifying and describing the key microbial players and biochemical pathways contributing to carbon, nitrogen and sulfur metabolism within the subarctic Pacific Ocean, this work provides a solid comparative genomic foundation for understanding the biogeochemical processes at work in marine OMZs around the globe.

Forever young: Mechanisms of natural anoxia tolerance and potential links to longevity

PubMed Central

Krivoruchko, Anastasia

2010-01-01

While mammals cannot survive oxygen deprivation for more than a few minutes without sustaining severe organ damage, some animals have mastered anaerobic life. Freshwater turtles belonging to the Trachemys and Chrysemys genera are the champion facultative anaerobes of the vertebrate world, often surviving without oxygen for many weeks at a time. The physiological and biochemical mechanisms that underlie anoxia tolerance in turtles include profound metabolic rate depression, post-translational modification of proteins, strong antioxidant defenses, activation of specific stress-responsive transcription factors, and enhanced expression of cyto-protective proteins. Turtles are also known for their incredible longevity and display characteristics of “negligible senescence.” We propose that the robust stress-tolerance mechanisms that permit long term anaerobiosis by turtles may also support the longevity of these animals. Many of the mechanisms involved in natural anoxia tolerance, such as hypometabolism or the induction of various protective proteins/pathways, have been shown to play important roles in mammalian oxygen-related diseases and improved understanding of how cells survive without oxygen could aid in the understanding and treatment of various pathological conditions that involve hypoxia or oxidative stress. In the present review we discuss the recent advances made in understanding the molecular nature of anoxia tolerance in turtles and the potential links between this tolerance and longevity. PMID:20716943

Oxygen tension differentially regulates the functional properties of cartilaginous tissues engineered from infrapatellar fat pad derived MSCs and articular chondrocytes.

PubMed

Buckley, C T; Vinardell, T; Kelly, D J

2010-10-01

For current tissue engineering or regenerative medicine strategies, chondrocyte (CC)- or mesenchymal stem cell (MSC)-seeded constructs are typically cultured in normoxic conditions (20% oxygen). However, within the knee joint capsule a lower oxygen tension exists. The objective of this study was to investigate how CCs and infrapatellar fad pad derived MSCs will respond to a low oxygen (5%) environment in 3D agarose culture. Our hypothesis was that culture in a low oxygen environment (5%) will enhance the functional properties of cartilaginous tissues engineered using both cell sources. Cell-encapsulated agarose hydrogel constructs (seeded with CCs or infrapatellar fat pad (IFP) derived MSCs) were prepared and cultured in a chemically defined serum-free medium in the presence (CCs and MSCs) or absence (CCs only) of transforming growth factor-beta3 (TGF-β3) in normoxic (20%) or low oxygen (5%) conditions for 42 days. Constructs were assessed at days 0, 21 and 42 in terms of mechanical properties, biochemical content and histologically. Low oxygen tension (5%) was observed to promote extracellular matrix (ECM) production by CCs cultured in the absence of TGF-β3, but was inhibitory in the presence of TGF-β3. In contrast, a low oxygen tension enhanced chondrogenesis of IFP constructs in the presence of TGF-β3, leading to superior mechanical functionality compared to CCs cultured in identical conditions. Extrapolating the results of this study to the in vivo setting, it would appear that joint fat pad derived MSCs may possess a superior potential to generate a functional repair tissue in low oxygen tensions. However, in the context of in vitro cartilage tissue engineering, CCs maintained in normoxic conditions in the presence of TGF-β3 generate the most mechanically functional tissue. Copyright © 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Cerebral oxygenation and hemodynamic changes during infant cardiac surgery: measurements by near infrared spectroscopy

NASA Astrophysics Data System (ADS)

du Plessis, Adre J.; Volpe, Joseph J.

1996-10-01

Despite dramatic advances in the survival rate among infants undergoing cardiac surgery for congenital heart disease, the incidence of brain injury suffered by survivors remains unacceptably high. This is largely due to our limited understanding of the complex changes in cerebral oxygen utilization and supply occurring during the intraoperative period as a result of hypothermia, neuroactive drugs, and profound circulatory changes. Current techniques for monitoring the adequacy of cerebral oxygen supply and utilization during hypothermic cardiac surgery are inadequate to address this complex problem and consequently to identify the infant at risk for such brain injury. Furthermore, this inability to detect imminent hypoxic- ischemic brain injury is likely to become all the more conspicuous as new neuroprotective strategies, capable of salvaging 'insulated' neuronal tissue form cell death, enter the clinical arena. Near infrared spectroscopy is a relatively new, noninvasive, and portable technique capable of interrogating the oxygenation and hemodynamics of tissue in vivo. These characteristics of the technique have generated enormous interest among clinicians in the ability of near infrared spectroscopy to elucidate the mechanisms of intraoperative brain injury and ultimately to identify infants oat risk for such injury. This paper reviews the experience with this technique to date during infant cardiac surgery.

Hybrid configurations via percutaneous access for extracorporeal membrane oxygenation: a single-center experience.

PubMed

Biscotti, Mauer; Lee, Alison; Basner, Robert C; Agerstrand, Cara; Abrams, Darryl; Brodie, Daniel; Bacchetta, Matthew

2014-01-01

Use of extracorporeal membrane oxygenation (ECMO) in adults has surged in recent years. Typical configurations are venovenous (VV), which provides respiratory support, or venoarterial (VA), which provides both respiratory and circulatory support. In patients supported with VV ECMO who develop hemodynamic compromise, an arterial limb can be added (venovenous-arterial ECMO) to provide additional circulatory support. For patients on VA ECMO who develop concomitant respiratory failure in the setting of some residual cardiac function, an oxygenated reinfusion limb can be added to the internal jugular vein (venoarterial-venous ECMO) to improve oxygen delivery to the cerebral and coronary circulation. Such hybrid configurations can provide differential support for various forms of cardiopulmonary failure. We describe 21 patients who ultimately received a hybrid configuration at our institution between 2012 and 2013. Eight patients (38.1%) died during ECMO support, four patients (19.0%) died after decannulation but before hospital discharge, and nine patients (42.9%) survived to hospital discharge. Our modest survival rate is likely related to the complexity and severity of illness of these patients, and this relative success suggests that hybrid configurations can be effective. It serves patients well to maintain a flexible and adaptable approach to ECMO configurations for their variable cardiopulmonary needs.

Accelerating Quinoline Biodegradation and Oxidation with Endogenous Electron Donors.

PubMed

Bai, Qi; Yang, Lihui; Li, Rongjie; Chen, Bin; Zhang, Lili; Zhang, Yongming; Rittmann, Bruce E

2015-10-06

Quinoline, a recalcitrant heterocyclic compound, is biodegraded by a series of reactions that begin with mono-oxygenations, which require an intracellular electron donor. Photolysis of quinoline can generate readily biodegradable products, such as oxalate, whose bio-oxidation can generate endogenous electron donors that ought to accelerate quinoline biodegradation and, ultimately, mineralization. To test this hypothesis, we compared three protocols for the biodegradation of quinoline: direct biodegradation (B), biodegradation after photolysis of 1 h (P1h+B) or 2 h (P2h+B), and biodegradation by adding oxalate commensurate to the amount generated from photolysis of 1 h (O1+B) or 2 h (O2+B). The experimental results show that P1h+B and P2h+B accelerated quinoline biodegradation by 19% and 50%, respectively, compared to B. Protocols O1+B and O2+B also gave 19% and 50% increases, respectively. During quinoline biodegradation, its first intermediate, 2-hydroxyquinoline, accumulated gradually in parallel to quinoline loss but declined once quinoline was depleted. Mono-oxygenation of 2-hydroxyquinoline competed with mono-oxygenation of quinoline, but the inhibition was relieved when extra electrons donors were added from oxalate, whether formed by UV photolysis or added exogenously. Rapid oxalate oxidation stimulated both mono-oxygenations, which accelerated the overall quinoline oxidation that provided the bulk of the electron donor.

Drivers of Variability of Diel-Cycling and Episodic Hypoxia In ...

EPA Pesticide Factsheets

Eutrophication of coastal ecosystems is a longstanding environmental concern, exacerbated by population growth and associated nutrient pollution, and ultimately resulting in increased incidence of hypoxia. Shallow and highly productive estuaries and embayments are particularly susceptible to diel-cycling hypoxia, associated with day-night cycles of production and respiration, which can cause extreme excursions in dissolved oxygen (DO) concentrations from anoxia to super-saturation within a single day. Diel oxygen dynamics in these systems are complex, and may be influenced by wind forcing, vertical and horizontal mixing, variation in freshwater inflow, cloud cover, and temperature. To better understand the environmental drivers of periodic hypoxia, this study examined four northern Gulf of Mexico Estuaries (Weeks Bay, AL; Wolf Bay, AL; Fowl River, AL; and St. Louis Bay, MS). Dissolved oxygen varied strongly on a diel basis in all four systems, with periods of sustained low oxygen (>24 h) observed in both Weeks Bay and Wolf Bay. The duration and persistence of hypoxia further varied in response to changing salinity regimes and regional weather. These results underscore the dynamic nature of hypoxia in shallow estuarine systems, and highlight the importance of combining fixed site continuous monitoring data with spatial hydrographic surveys to accurately resolve DO dynamics. This abstract is submitted for presentation at the CERF conference held Nov 8-12 in Oregon

The New World Health Organization Recommendations on Perioperative Administration of Oxygen to Prevent Surgical Site Infections: A Dangerous Reductionist Approach?

PubMed

Wenk, Manuel; Van Aken, Hugo; Zarbock, Alexander

2017-08-01

In October 2016, the World Health Organization (WHO) published recommendations for preventing surgical site infections (SSIs). Among those measures is a recommendation to administer oxygen at an inspired fraction of 80% intra- and postoperatively for up to 6 hours. SSIs have been identified as a global health problem, and the WHO should be commended for their efforts. However, this recommendation focuses only on the patient's "wound," ignores other organ systems potentially affected by hyperoxia, and may ultimately worsen patient outcomes.The WHO advances a "strong recommendation" for the use of a high inspired oxygen fraction even though the quality of evidence is only moderate. However, achieving this goal by disregarding other potentially lethal complications seems inappropriate, particularly in light of the weak evidence underpinning the use of high fractions of oxygen to prevent SSI. Use of such a strategy thus should be intensely discussed by anesthesiologists and perioperative physicians.Normovolemia, normotension, normoglycemia, normothermia, and normoventilation can clearly be safely applied to most patients in most clinical scenarios. But the liberal application of hyperoxemia intraoperatively and up to 6 hours postoperatively, as suggested by the WHO, is questionable from the viewpoint of anesthesia and perioperative medicine, and its effects will be discussed in this article.

Enhanced oxygen permeability in membrane-bottomed concave microwells for the formation of pancreatic islet spheroids.

PubMed

Lee, GeonHui; Jun, Yesl; Jang, HeeYeong; Yoon, Junghyo; Lee, JaeSeo; Hong, MinHyung; Chung, Seok; Kim, Dong-Hwee; Lee, SangHoon

2018-01-01

Oxygen availability is a critical factor in regulating cell viability that ultimately contributes to the normal morphogenesis and functionality of human tissues. Among various cell culture platforms, construction of 3D multicellular spheroids based on microwell arrays has been extensively applied to reconstitute in vitro human tissue models due to its precise control of tissue culture conditions as well as simple fabrication processes. However, an adequate supply of oxygen into the spheroidal cellular aggregation still remains one of the main challenges to producing healthy in vitro spheroidal tissue models. Here, we present a novel design for controlling the oxygen distribution in concave microwell arrays. We show that oxygen permeability into the microwell is tightly regulated by varying the poly-dimethylsiloxane (PDMS) bottom thickness of the concave microwells. Moreover, we validate the enhanced performance of the engineered microwell arrays by culturing non-proliferated primary rat pancreatic islet spheroids on varying bottom thickness from 10 μm to 1050 μm. Morphological and functional analyses performed on the pancreatic islet spheroids grown for 14 days prove the long-term stability, enhanced viability, and increased hormone secretion under the sufficient oxygen delivery conditions. We expect our results could provide knowledge on oxygen distribution in 3-dimensional spheroidal cell structures and critical design concept for tissue engineering applications. In this study, we present a noble design to control the oxygen distribution in concave microwell arrays for the formation of highly functional pancreatic islet spheroids by engineering the bottom of the microwells. Our new platform significantly enhanced oxygen permeability that turned out to improve cell viability and spheroidal functionality compared to the conventional thick-bottomed 3-D culture system. Therefore, we believe that this could be a promising medical biotechnology platform to further develop high-throughput tissue screening system as well as in vivo-mimicking customised 3-D tissue culture systems. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Prognostic biomarkers in osteoarthritis

PubMed Central

Attur, Mukundan; Krasnokutsky-Samuels, Svetlana; Samuels, Jonathan; Abramson, Steven B.

2013-01-01

Purpose of review Identification of patients at risk for incident disease or disease progression in osteoarthritis remains challenging, as radiography is an insensitive reflection of molecular changes that presage cartilage and bone abnormalities. Thus there is a widely appreciated need for biochemical and imaging biomarkers. We describe recent developments with such biomarkers to identify osteoarthritis patients who are at risk for disease progression. Recent findings The biochemical markers currently under evaluation include anabolic, catabolic, and inflammatory molecules representing diverse biological pathways. A few promising cartilage and bone degradation and synthesis biomarkers are in various stages of development, awaiting further validation in larger populations. A number of studies have shown elevated expression levels of inflammatory biomarkers, both locally (synovial fluid) and systemically (serum and plasma). These chemical biomarkers are under evaluation in combination with imaging biomarkers to predict early onset and the burden of disease. Summary Prognostic biomarkers may be used in clinical knee osteoarthritis to identify subgroups in whom the disease progresses at different rates. This could facilitate our understanding of the pathogenesis and allow us to differentiate phenotypes within a heterogeneous knee osteoarthritis population. Ultimately, such findings may help facilitate the development of disease-modifying osteoarthritis drugs (DMOADs). PMID:23169101

Cell-Free Reconstitution of Multivesicular Body Formation and Receptor Sorting

PubMed Central

Sun, Wei; Vida, Thomas A.; Sirisaengtaksin, Natalie; Merrill, Samuel A.; Hanson, Phyllis I.; Bean, Andrew J.

2010-01-01

The number of surface membrane proteins and their residence time on the plasma membrane are critical determinants of cellular responses to cues that can control plasticity, growth and differentiation. After internalization, the ultimate fate of many plasma membrane proteins is dependent on whether they are sorted for internalization into the lumenal vesicles of multivesicular bodies (MVBs), an obligate step prior to lysosomal degradation. To help to elucidate the mechanisms underlying MVB sorting, we have developed a novel cell-free assay that reconstitutes the sorting of a prototypical membrane protein, the epidermal growth factor receptor, with which we have probed some of its molecular requirements. The sorting event measured is dependent on cytosol, ATP, time, temperature and an intact proton gradient. Depletion of Hrs inhibited biochemical and morphological measures of sorting that were rescued by inclusion of recombinant Hrs in the assay. Moreover, depletion of signal-transducing adaptor molecule (STAM), or addition of mutated ATPase-deficient Vps4, also inhibited sorting. This assay reconstitutes the maturation of late endosomes, including the formation of internal vesicles and the sorting of a membrane protein, and allows biochemical investigation of this process. PMID:20214752

Raman spectroscopic investigation of spinal cord injury in a rat model

NASA Astrophysics Data System (ADS)

Saxena, Tarun; Deng, Bin; Stelzner, Dennis; Hasenwinkel, Julie; Chaiken, Joseph

2011-02-01

Raman spectroscopy was used to study temporal molecular changes associated with spinal cord injury (SCI) in a rat model. Raman spectra of saline-perfused, injured, and healthy rat spinal cords were obtained and compared. Two injury models, a lateral hemisection and a moderate contusion were investigated. The net fluorescence and the Raman spectra showed clear differences between the injured and healthy spinal cords. Based on extensive histological and biochemical characterization of SCI available in the literature, these differences were hypothesized to be due to cell death, demyelination, and changes in the extracellular matrix composition, such as increased expression of proteoglycans and hyaluronic acid, at the site of injury where the glial scar forms. Further, analysis of difference spectra indicated the presence of carbonyl containing compounds, hypothesized to be products of lipid peroxidation and acid catalyzed hydrolysis of glycosaminoglycan moieties. These results compared well with in vitro experiments conducted on chondroitin sulfate sugars. Since the glial scar is thought to be a potent biochemical barrier to nerve regeneration, this observation suggests the possibility of using near infrared Raman spectroscopy to study injury progression and explore potential treatments ex vivo, and ultimately monitor potential remedial treatments within the spinal cord in vivo.

Regioselective Reactions for Programmable Resveratrol Oligomer Synthesis

PubMed Central

Snyder, Scott A.; Gollner, Andreas; Chiriac, Maria I.

2011-01-01

Although much attention has been devoted to resveratrol, a unique polyphenol produced by plants throughout the world and credited as potentially being responsible for the so-called “French paradox” given its broad spectrum activity, the hundreds of oligomeric materials derived from it have been largely ignored despite their similarly high biochemical potential. Challenges in achieving their isolation in quantity from natural sources, coupled with an inability to rationally prepare them in the laboratory, are the main culprits. Here we show that a programmable, controlled, and potentially scaleable synthesis of the resveratrol family is possible through a unique three-stage design. These efforts required novel tactics coupled with strategy- and reagent-guided functionalizations to differentiate two distinct cores possessing multiple sites with the same and/or similar reactivity, ultimately leading to five higher-order natural products. We anticipate that this work 1) demonstrates that challenging, positionally-selective functionalizations of complex materials are possible where biosynthetic studies have indicated otherwise, 2) provides materials and tools to finally unlock the full biochemical potential of the family, particularly from the standpoint of activity and drug-property optimization, and 3) affords an intellectual framework to potentially access other oligomeric families controllably. PMID:21697944

Advanced Biotelemetry Systems for Space Life Sciences: PH Telemetry

NASA Technical Reports Server (NTRS)

Hines, John W.; Somps, Chris; Ricks, Robert; Kim, Lynn; Connolly, John P. (Technical Monitor)

1995-01-01

The SENSORS 2000! (S2K!) program at NASA's Ames Research Center is currently developing a biotelemetry system for monitoring pH and temperature in unrestrained subjects. This activity is part of a broader scope effort to provide an Advanced Biotelemetry System (ABTS) for use in future space life sciences research. Many anticipated research endeavors will require biomedical and biochemical sensors and related instrumentation to make continuous inflight measurements in a variable-gravity environment. Since crew time is limited, automated data acquisition, data processing, data storage, and subject health monitoring are required. An automated biochemical and physiological data acquisition system based on non invasive or implantable biotelemetry technology will meet these requirements. The ABTS will ultimately acquire a variety of physiological measurands including temperature, biopotentials (e.g. ECG, EEG, EMG, EOG), blood pressure, flow and dimensions, as well as chemical and biological parameters including pH. Development activities are planned in evolutionary, leveraged steps. Near-term activities include 1) development of a dual channel pH/temperature telemetry system, and 2) development of a low bandwidth, 4-channel telemetry system, that measures temperature, heart rate, pressure, and pH. This abstract describes the pH/temperature telemeter.