The role of external and internal mass transfer in the process of Cu2+ removal by natural mineral sorbents.

PubMed

Sljivić, M; Smiciklas, I; Plećas, I; Pejanović, S

2011-07-01

The kinetics of Cu2+ sorption on to zeolite, clay and diatomite was investigated as a function of initial metal concentrations. For consideration of the mass transfer phenomena, single resistance models based on both film and intraparticle diffusion were tested and compared. The obtained results suggested that the rate-limiting step in Cu2+ sorption strongly depended on the sorbent type, as well as on initial cation concentration. The decrease in external mass transfer coefficients with the increase in initial metal concentrations was in excellent agreement with expressions based on Sherwood and Schmidt dimensionless numbers. The internal diffusivities through zeolite particles were in the range 1.0 x 10(-11) to 1.0 x 10(-13) m2/min, depending on the Cu2+ concentration and the applied theoretical model.

The Effect of Age and Weight on Vancomycin Serum Trough Concentrations in Pediatric Patients

PubMed Central

Madigan, Theresa; Sieve, Ronald M.; Graner, Kevin K.; Banerjee, Ritu

2013-01-01

Background Vancomycin treatment failure has been associated with low serum vancomycin trough concentrations, prompting recommendations to increase the daily doses in adults and children. Despite more aggressive vancomycin dosing, there continues to be significant variability in vancomycin trough concentrations in pediatric patients. Methods To determine if vancomycin trough concentrations in pediatric patients differ by age and weight, we reviewed records of hospitalized patients who received vancomycin between 2008 and 2012. Patients were divided into groups that received vancomycin 40 mg/kg/day (2008 to 2009) or 60 mg/kg/day (2010 to 2012). Vancomycin trough concentrations were compared between groups and within the 60-mg/kg/day group, stratified by patient age and weight. Results After increasing the vancomycin dose from 40 mg/kg/day to 60 mg/kg/day, initial trough concentrations increased significantly in patients younger than 2 and greater than 6 years of age, but not in patients between the ages of 2 and 5 years. In the 60-mg/kg/day group, only 16.7% of patients between 2 and 5 years of age had initial trough concentrations in the therapeutic range (10 mcg/mL to 20 mcg/mL). Initial trough concentrations were therapeutic in a greater proportion of patients ages 6 years to 12 years (38.7%) and 13 years to 18 years (63.0%). Patients between the ages of 13 and 18 had the highest proportion of supratherapeutic initial vancomycin trough concentrations (14.8%). Patients weighing > 50 kg had significantly higher trough concentrations than patients ≤ 50 kg (17.1 mcg/mL vs. 9.3 mcg/mL; p<0.001). Conclusion Although increasing the vancomycin dose from 40 mg/kg/day to 60 mg/kg/day led to a significant increase in vancomycin trough concentrations, a large proportion of patients receiving 60 mg/kg/day of vancomycin had trough concentrations outside of the therapeutic range. Specifically, patients younger than 6 years tend to have low trough concentrations, while adolescents and children > 50 kg are more likely to have elevated trough concentrations. Vancomycin dosing strategies in pediatric patients should consider age and weight as well as renal function and indication. PMID:23864541

Adsorption of cesium on cement mortar from aqueous solutions.

PubMed

Volchek, Konstantin; Miah, Muhammed Yusuf; Kuang, Wenxing; DeMaleki, Zack; Tezel, F Handan

2011-10-30

The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L(-1) and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L(-1) while the respective surface concentration on coupons varied from 0.0395 to 22.34 μg cm(-2). Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol(-1) suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Effect of pathogen concentrations on removal of Cryptosporidium and Giardia by conventional drinking water treatment.

PubMed

Assavasilavasukul, Prapakorn; Lau, Boris L T; Harrington, Gregory W; Hoffman, Rebecca M; Borchardt, Mark A

2008-05-01

The presence of waterborne enteric pathogens in municipal water supplies contributes risk to public health. To evaluate the removal of these pathogens in drinking water treatment processes, previous researchers have spiked raw waters with up to 10(6) pathogens/L in order to reliably detect the pathogens in treated water. These spike doses are 6-8 orders of magnitude higher than pathogen concentrations routinely observed in practice. In the present study, experiments were conducted with different sampling methods (i.e., grab versus continuous sampling) and initial pathogen concentrations ranging from 10(1) to 10(6) pathogens/L. Results showed that Cryptosporidium oocyst and Giardia cyst removal across conventional treatment were dependent on initial pathogen concentrations, with lower pathogen removals observed when lower initial pathogen spike doses were used. In addition, higher raw water turbidity appeared to result in higher log removal for both Cryptosporidium oocysts and Giardia cysts.

Alternative Sodium Recovery Technology—High Hydroxide Leaching: FY10 Status Report

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

Mahoney, Lenna A.; Neiner, Doinita; Peterson, Reid A.

2011-02-04

Boehmite leaching tests were carried out at NaOH concentrations of 10 M and 12 M, temperatures of 85°C and 60°C, and a range of initial aluminate concentrations. These data, and data obtained during earlier 100°C tests using 1 M and 5 M NaOH, were used to establish the dependence of the boehmite dissolution rate on hydroxide concentration, temperature, and initial aluminate concentration. A semi-empirical kinetic model for boehmite leaching was fitted to the data and used to calculate the NaOH additions required for leaching at different hydroxide concentrations. The optimal NaOH concentration for boehmite leaching at 85°C was estimated, basedmore » on minimizing the amount of Na that had to be added in NaOH to produce a given boehmite conversion.« less

Changes in oral ethanol self-administration patterns resulting from ethanol concentration manipulations.

PubMed

Slawecki, C J; Samson, H H

1997-09-01

A variety of initiation procedures have been used to develop oral ethanol consumption. Using the sucrose-substitution procedure, oral self-administration of ethanol-water solutions with ethanol concentrations as high as 40% can be initiated in food- and fluid-sated rats. An important question for these models is the relationship between ethanol concentration and self-administration patterns after initiation. This study examined the differential patterns of ethanol self-administration maintained by a range of ethanol solutions (10 to 30%) over a 5-week period, compared with rats maintained on 10% ethanol for 5 weeks. In 43 male Long Evans rats, the sucrose-substitution procedure was used to initiate responding maintained by 10% ethanol on a Fixed Ratio 4 schedule of reinforcement. The ethanol concentration presented was then increased to 30% in stepwise fashion and then returned to 10% [Ethanol Concentration Manipulation (ECM) group, n = 32], or 10% ethanol was maintained as the reinforcer for 5 weeks [Control (Con) group, n = 11]. Significant increases in ethanol intake and decreases in responding were associated with increased ethanol concentration. Although no overall differences in total session responding were observed in either group between week 1 and week 5 (10E vs. 10E), examination of changes in initial low responders of the ECM group revealed significant increases in responding that were not observed in the initial low responders of the Con group. Significant increases in momentary response rates were observed on both the ECM and Con groups, independent of the ethanol concentration presented. Increases in response rate in the ECM group were the result of increases in initial low rate and high rate responders; however, the increased response rates in the Con group were the result of increases only in the initial low rate responders. These data suggest that the ECM procedure can aid in the initiation of ethanol self-administration and may be particularly useful in rats of heterogeneous stock.

An analysis of nitrification during the aerobic digestion of secondary sludges.

PubMed

Bhargava, D S; Datar, M T

1989-01-01

Investigations were undertaken to study the occurrence and progress of nitrification during aerobic digestion of activated sludge in a wide range of initial concentrations of total solids (1000 to 80 000 mg litre(-1), initial pH range of 4.5 to 10.4 and digestion temperature range of 5 degrees to 60 degrees C. Batch aerobic digestion studies on activated sludge grown on wastewater (enriched with organic solids from human excretal material) indicate that almost complete elimination of the 'biodegradable' matter of the activated sludge was one of the essential prerequisites to initiate nitrification. Favourable ranges of temperature and pH for nitrification were observed to be 25 degrees to 30 degrees C and 6.0 to 8.3, respectively. With all favourable conditions, a minimum period of about 2 days was necessary for population build-up of genera Nitrosomonas and Nitrobacter, and to initiate nitrification. Nitrate formation invariably lagged behind nitrite formation, but under certain conditions both phases of nitrification were observed to progress hand in hand.

Nitrate release from waste rock dumps in the Elk Valley, British Columbia, Canada.

PubMed

Mahmood, Fazilatun N; Barbour, S Lee; Kennedy, C; Hendry, M Jim

2017-12-15

The origin, distribution and leaching of nitrate (NO 3 - ) from coal waste rock dumps in the Elk Valley, British Columbia, Canada were defined using chemical and NO 3 - isotope analyses (δ 15 N- and δ 18 O-NO 3 - ) of solids samples of pre- and post-blast waste rock and from thick (up to 180m) unsaturated waste rock dump profiles constructed between 1982 and 2012 as well as water samples collected from a rock drain located at the base of one dump and effluent from humidity cell (HC) and leach pad (LP) tests on waste rock. δ 15 N- and δ 18 O-NO 3 - values and NO 3 - concentrations of waste rock and rock drain waters confirmed the source of NO 3 - in the waste rock to be explosives and that limited to no denitrification occurs in the dump. The average mass of N released during blasting was estimated to be about 3-6% of the N in the explosives. NO 3 - concentrations in the fresh-blast waste rock and recently placed waste rock used for the HC and LP experiments were highly variable, ranging from below detection to 241mg/kg. The mean and median concentrations of these samples ranged from 10-30mg/kg. In this range of concentrations, the initial aqueous concentration of fresh-blasted waste rock could range from approximately 200-600mg NO 3 - -N/L. Flushing of NO 3 - from the HCs, LPs and a deep field profile was simulated using a scale dependent leaching efficiency (f) where f ranged from 5-15% for HCs, to 35-80% for the LPs, to 80-90% for the field profile. Our findings show aqueous phase NO 3 - from blasting residuals is present at highly variable initial concentrations in waste rock and the majority of this NO 3 - (>75%) should be flushed by recharging water during displacement of the first stored water volume. Copyright © 2017 Elsevier B.V. All rights reserved.

Persistence and distribution of 4-nonylphenol in water, sediment, macrophytes, and wall material of littoral enclosures

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

Heinis, L.J.; Tunell, R.; Liber, K.

1994-12-31

Eighteen enclosures (5 m x 10 m) were constructed in the littoral zone of a 2-ha pond near Duluth, MN. Each enclosure consisted of 5 m of natural shoreline and three walls of an inert plastic. The enclosures had an average surface area of 31.9 m{sup 2} , an average depth of 0.6 m and an average water volume of 33.1 m{sup 3}. The enclosure waters were treated with the alkyl phenol ethoxylate precursor and degradation product 4-nonylphenol. Application was accomplished by sub-surface injection over a 20-day period with a 2 day frequency. Nominal aqueous concentrations were 0, 3, 30,more » 100 and 300 {mu}g/L. Concentrations of 4-nonylphenol were monitored during and after application in the water, sediment, macrophytes, and enclosure wall material. Average maximum water concentrations ranged from 96.5% of nominal to 62.0% of nominal and average minimum water concentrations ranged from 33.3% of nominal to 29.5% of nominal during the application period. Water concentrations decreased exponentially after application ended. Sediment concentrations during the application period were constant from 8 to 20 d and peak concentrations occurred 48 d after application began. Macrophyte concentrations peaked 21 d after initial application with a steady decline through 76 d. Enclosure wall material concentrations reached a peak 3 h before the final application. A gradual decline occurred until 34 d after initial application followed by a more rapid dissipation.« less

[Adsorption characteristics of acetone and butanone onto honeycomb ZSM-5 molecular sieve].

PubMed

Du, Juan; Luan, Zhi-Qiang; Xie, Qiang; Ye, Ping-Wei; Li, Kai; Wang, Xi-Qin

2013-12-01

Adsorption capacity of acetone and acetone-butanone mixture onto honeycomb ZSM-5 molecular sieve was measured in this paper, and the influences of relative humidity, initial adsorbate concentration and airflow velocity on the adsorption process were investigated. Besides, adsorption performance parameters were calculated by Wheeler's equation. The results showed that relative humidity had no obvious influence on the acetone adsorption performance, which suggests that this material has good hydrophobic ability; in the low concentration range, the dynamic saturated adsorption capacity of acetone increased with the increase of initial concentration, but in the occasion of high concentration of acetone gas (more than 9 mg x L(-1)), the dynamic saturated adsorption capacity maintained at a certain level and did not vary with the increase of initial concentration; the increase of air flow velocity resulted in significant increase of acetone adsorption rate constant, at the same time the critical layer thickness of the adsorbent bed also increased significantly. In the cases of acetone-butanone mixture, the adsorption capacity of butanone onto ZSM-5 was clearly higher than that of acetone.

Xanthan production on polyurethane foam and its enhancement by air pressure pulsation.

PubMed

Zhang, Zhi-guo; Chen, Hong-zhang

2010-12-01

In this study, we evaluated the feasibility of solid-state fermentation (SSF) on polyurethane foam (PUF) for xanthan production. The effects of air pressure pulsation (APP) on biomass accumulation and final xanthan concentration were also studied. Under suitable conditions (15% inoculum, 0.5-cm (side length) PUF cubes, 15 mL medium per gram cubes and 4.5 cm bed depth), the broth was dispersed on the PUF as a film. When the initial glucose concentration in the media was low (20 and 40 g L⁻¹), there was no significant difference between the final xanthan concentration in static SSF and submerged fermentation (SMF). When high initial glucose concentrations (60 and 80 g L⁻¹) were used, the final gum concentrations in SSF were much higher than those in SMF. When the APP technique was applied in xanthan production with a medium containing a high glucose concentration (80 g L⁻¹), the oxygen consumption rate of Xanthomonas campestris was significantly enhanced at the later stages of fermentation, and both the biomass and xanthan concentration were improved. The results indicated that SSF on PUF is suitable for xanthan preparation, especially when the initial glucose concentration ranged from 60 to 80 g L⁻¹. Those results also demonstrated that APP technology can be used to enhance xanthan yields.

Effect of Sodium Chloride and pH on Enterotoxin C Production

PubMed Central

Genigeorgis, Constantin; Foda, Mohamed S.; Mantis, Antony; Sadler, Walter W.

1971-01-01

Growth and production of enterotoxin C by Staphylococcus aureus strain 137 in 3% + 3% protein hydrolysate powder N-Z Amine NAK broths with 0 to 12% NaCl and an initial pH of 4.00 to 9.83 were studied during an 8-day incubation period at 37 C. Growth was initiated at pH values as low as 4.00 and as high as 9.83 at 0% salt level as long as the inoculum contained at least 108 cells per ml. Rate of growth decreased as the NaCl concentration was increased gradually to 12%. Enterotoxin C was produced in broths inoculated with 108 cells per ml and above and having initial pH ranges of 4.00 to 9.83, 4.40 to 9.43, 4.50 to 8.55 and respective NaCl concentrations of 0, 4, and 8%. In the presence of 10% NaCl, the pH range supporting enterotoxin C production was 5.45 to 7.30 for an inoculum level of 108 cells per ml and 6.38 to 7.30 for 3.6 × 106 cells per ml. In repeated experiments in which the inoculum contained 108 cells per ml, we failed to demonstrate enterotoxin C production in broths with 12% NaCl and a pH range of 4.50 to 8.55 and concentrated up to 14 times. The effect of NaCl on enterotoxin C production followed the same pattern as its effect on enterotoxin B production. As the concentration of NaCl increased from 0 to 10%, yields of enterotoxin B and C decreased to undetectable amounts. PMID:5574320

Parameters and kinetics of olive mill wastewater dephenolization by immobilized Rhodotorula glutinis cells.

PubMed

Bozkoyunlu, Gaye; Takaç, Serpil

2014-01-01

Olive mill wastewater (OMW) with total phenol (TP) concentration range of 300-1200 mg/L was treated with alginate-immobilized Rhodotorula glutinis cells in batch system. The effects of pellet properties (diameter, alginate concentration and cell loading (CL)) and operational parameters (initial TP concentration, agitation rate and reusability of pellets) on dephenolization of OMW were studied. Up to 87% dephenolization was obtained after 120 h biodegradations. The utilization number of pellets increased with the addition of calcium ions into the biodegradation medium. The overall effectiveness factors calculated for different conditions showed that diffusional limitations arising from pellet size and pellet composition could be neglected. Mass transfer limitations appeared to be more effective at high substrate concentrations and low agitation rates. The parameters of logistic model for growth kinetics of R. glutinis in OMW were estimated at different initial phenol concentrations of OMW by curve-fitting of experimental data with the model.

Metabolic and respiratory status of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii).

PubMed

Innis, Charles J; Tlusty, Michael; Merigo, Constance; Weber, E Scott

2007-08-01

"Cold-stunning" of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This study investigated initial and convalescent venous blood gas, acid-base, and critical plasma biochemical data for 26 naturally cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) from Cape Cod, MA, USA. Samples were analyzed for pH, pCO(2), pO(2), bicarbonate, plasma osmolality, sodium, potassium, chloride, ionized calcium, ionized magnesium, glucose, lactate, and blood urea nitrogen using a clinical point-of-care analyzer. Data were corrected for the patient's body temperature using both species-specific and more general correction methods. In general, venous blood gas, acid-base, and plasma biochemical data obtained for surviving cold-stunned Kemp's ridley sea turtles were consistent with previously documented data for sea turtles exposed to a wide range of temperatures and physiologic stressors. Data indicated that turtles were initially affected by metabolic and respiratory acidosis. Initial pH-corrected ionized calcium concentrations were lower than convalescent concentrations, and initial pH-corrected ionized magnesium concentrations were higher than convalescent concentrations.

A comparative study of the biosorption of iron(III)-cyanide complex anions to Rhizopus arrhizus and Chlorella vulgaris

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

Aksu, Z.; Calik, A.

1999-03-01

In this study a comparative biosorption of iron(III)-cyanide complex anions from aqueous solutions to Rhizopus arrhizus and Chlorella vulgaris was investigated. The iron(III)-cyanide complex ion-binding capacities of the biosorbents were shown as a function of initial pH, initial iron(III)-cyanide complex ion, and biosorbent concentrations. The results indicated that a significant reduction of iron(III)-cyanide complex ions was achieved at pH 13, a highly alkaline condition for both the biosorbents. The maximum loading capacities of the biosorbents were found to be 612.2 mg/g for R.arrhizus at 1,996.2 mg/L initial iron(III)-cyanide complex ion concentration and 387.0 mg/g for C. vulgaris at 845.4 mg/Lmore » initial iron(III)-cyanide complex ion concentration at this pH. The Freundlich, Langmuir, and Redlich-Peterson adsorption models were fitted to the equilibrium data at pH 3, 7, and 13. The equilibrium data of the biosorbents could be best fitted by all the adsorption models over the entire concentration range at pH 13.« less

Neutronics calculations on the impact of burnable poisons to safety and non-proliferation aspects of inert matrix fuel

NASA Astrophysics Data System (ADS)

Pistner, C.; Liebert, W.; Fujara, F.

2006-06-01

Inert matrix fuels (IMF) with plutonium may play a significant role to dispose of stockpiles of separated plutonium from military or civilian origin. For reasons of reactivity control of such fuels, burnable poisons (BP) will have to be used. The impact of different possible BP candidates (B, Eu, Er and Gd) on the achievable burnup as well as on safety and non-proliferation aspects of IMF are analyzed. To this end, cell burnup calculations have been performed and burnup dependent reactivity coefficients (boron worth, fuel temperature and moderator void coefficient) were calculated. All BP candidates were analyzed for one initial BP concentration and a range of different initial plutonium-concentrations (0.4-1.0 g cm-3) for reactor-grade plutonium isotopic composition as well as for weapon-grade plutonium. For the two most promising BP candidates (Er and Gd), a range of different BP concentrations was investigated to study the impact of BP concentration on fuel burnup. A set of reference fuels was identified to compare the performance of uranium-fuels, MOX and IMF with respect to (1) the fraction of initial plutonium being burned, (2) the remaining absolute plutonium concentration in the spent fuel and (3) the shift in the isotopic composition of the remaining plutonium leading to differences in the heat and neutron rate produced. In the case of IMF, the remaining Pu in spent fuel is unattractive for a would be proliferator. This underlines the attractiveness of an IMF approach for disposal of Pu from a non-proliferation perspective.

Does Initial Leaf Chemistry Affect the Contribution of Insects, Fungi, and Bacteria to Leaf Breakdown in a Lowland Tropical Stream?

NASA Astrophysics Data System (ADS)

Ardon, M.; Pringle, C. M.

2005-05-01

We examined effects of initial leaf chemistry of six common riparian species on the relative contribution of fungi, bacteria, and invertebrates to leaf breakdown in a lowland stream in Costa Rica. We hypothesized that fungi and bacteria would contribute more to the breakdown of species with low concentrations of secondary (tannins and phenolics) and structural (cellulose and lignin) compounds, while invertebrates would be more important in the processing of species with high concentrations of secondary and structural compounds. We incubated single species leaf bags of six common riparian species, representing a range in secondary and structural compounds, in a third-order stream at La Selva Biological Station, Costa Rica. We measured leaf chemistry during the breakdown process. We determined fungal biomass using ergosterol methods, bacteria using DAPI counts, and invertebrate biomass using length-weight regressions. We then used biomass estimates for each group to determine their contribution to the overall breakdown process. Breakdown rates ranged from very fast (Trema integerima, k = 0.23 day-1) to slow (Zygia longifolia , k = 0.011 day-1). While analyses are still under way, preliminary results support our initial hypothesis that fungi contribute more to the break down of leaves from tree species with low concentrations of secondary and structural compounds.

Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs.

PubMed

Yi, G F; Gaines, A M; Ratliff, B W; Srichana, P; Allee, G L; Perryman, K R; Knight, C D

2006-07-01

Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P < 0.05) and improved G:F (linear; P < 0.002). The pooled data of Exp. 1 (SAA study) and Exp. 2 indicated that increasing TID SAA from 0.63 to 0.90% increased ADG (quadratic; P < 0.01) and improved G:F (quadratic; P < 0.01). Various methods of analyzing the growth response surface indicated that the optimal TID Lys concentration ranged from 1.28 to 1.32% for ADG (Exp. 1), and the optimal TID SAA concentration ranged from 0.73 to 0.77% for ADG and 0.80 to 0.83% for G:F (pooled Exp. 1 and 2), respectively. In Exp. 3, increasing TID SAA concentrations from 0.50 to 0.68% resulted in a linear improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity.

Assembly and testing of a 1.8 by 3.7 meter Fresnel lens solar concentrator

NASA Technical Reports Server (NTRS)

Robertson, J. E.

1977-01-01

A project was initiated to establish a technical data base on line focusing acrylic Fresnel lenses for use in a solar collector system that could generate temperatures in the range of 200 C to 370 C. The effort was originally directed toward electric power generation in the 100 to 10,000 kWe range using a distributed collector approach. However, as the program progressed, it centered on the development of a concentrator/collector subsystem concept that could meet the general requirement of thermal delivery within the 200 C to 370 C range. The expanded list of possible applications includes commercial heating/cooling and industrial process heat as well as electric power generation.

Equilibrium and kinetic modelling of Cd(II) biosorption by algae Gelidium and agar extraction algal waste.

PubMed

Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

2006-01-01

In this study an industrial algal waste from agar extraction has been used as an inexpensive and effective biosorbent for cadmium (II) removal from aqueous solutions. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction. Equilibrium data follow both Langmuir and Redlich-Peterson models. The parameters of Langmuir equilibrium model are q(max)=18.0 mgg(-1), b=0.19 mgl(-1) and q(max)=9.7 mgg(-1), b=0.16 mgl(-1), respectively for Gelidium and the algal waste. Kinetic experiments were conducted at initial Cd(II) concentrations in the range 6-91 mgl(-1). Data were fitted to pseudo-first- and second-order Lagergren models. For an initial Cd(II) concentration of 91 mgl(-1) the parameters of the pseudo-first-order Lagergren model are k(1,ads)=0.17 and 0.87 min(-1); q(eq)=16.3 and 8.7 mgg(-1), respectively, for Gelidium and algal waste. Kinetic constants vary with the initial metal concentration. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model. The model successfully predicts Cd(II) concentration profiles and provides significant insights on the biosorbents performance. The homogeneous diffusivity, D(h), is in the range 0.5-2.2 x10(-8) and 2.1-10.4 x10(-8)cm(2)s(-1), respectively, for Gelidium and algal waste.

Effect of tetrastarch (hydroxyethyl starch 130/0.4) on plasma creatinine concentration in cats: a retrospective analysis (2010-2015).

PubMed

Yozova, Ivayla D; Howard, Judith; Adamik, Katja N

2017-10-01

Objectives The objective was to determine survival and changes in creatinine concentrations after administration of 6% tetrastarch (hydroxyethyl starch [HES] 130/0.4) vs crystalloids in critically ill cats. Methods The medical records were reviewed for cats admitted to the intensive care unit with at least two plasma creatinine measurements and initial concentrations not exceeding the upper reference interval. Cats were excluded if they had received HES prior to admission or if they had received fluid therapy for <24 h between initial and subsequent measurements. Changes in creatinine concentrations were evaluated as the percentage change from initial values to the maximum subsequent measurements. Cats receiving only crystalloids were assigned to the crystalloid group; cats receiving only HES or HES and crystalloids were assigned to the HES group. Results Ninety-three cats were included in the study (62 in the crystalloid group, 31 in the HES group). The total median cumulative HES dose was 94 ml/kg (range 26-422 ml/kg) and 24 ml/kg/day (range 16-42 ml/kg/day). No difference was detected between the groups for age, sex, body weight or mortality. The HES group had a significantly longer length of hospitalisation ( P = 0.012), lower albumin concentrations ( P <0.001), higher Acute Patient Physiologic and Laboratory Evaluation scores ( P = 0.037) and higher incidence of systemic inflammatory response syndrome ( P = 0.009) and sepsis ( P = 0.013). There was no significant difference in initial, maximum or maximum change in creatinine concentrations between the groups. Moreover, there was no significant difference in maximum change in creatinine concentrations in the subgroups of cats with systemic inflammatory response syndrome or sepsis. Conclusions and relevance In this population of cats, the administration of HES did not result in a significantly greater increase in creatinine from values measured on admission or higher mortality compared with administration of crystalloids. Further prospective studies are needed to assess both safety and efficacy of HES in cats before recommendations can be made.

Anti-Biofilm Performance of Three Natural Products against Initial Bacterial Attachment

PubMed Central

Salta, Maria; Wharton, Julian A.; Dennington, Simon P.; Stoodley, Paul; Stokes, Keith R.

2013-01-01

Marine bacteria contribute significantly towards the fouling consortium, both directly (modern foul release coatings fail to prevent “slime” attachment) and indirectly (biofilms often excrete chemical cues that attract macrofouling settlement). This study assessed the natural product anti-biofilm performance of an extract of the seaweed, Chondrus crispus, and two isolated compounds from terrestrial sources, (+)-usnic acid and juglone, against two marine biofilm forming bacteria, Cobetia marina and Marinobacter hydrocarbonoclasticus. Bioassays were developed using quantitative imaging and fluorescent labelling to test the natural products over a range of concentrations against initial bacterial attachment. All natural products affected bacterial attachment; however, juglone demonstrated the best anti-biofilm performance against both bacterial species at a concentration range between 5–20 ppm. In addition, for the first time, a dose-dependent inhibition (hormetic) response was observed for natural products against marine biofilm forming bacteria. PMID:24192819

Notes on initial disturbance fields for the transition problem

NASA Technical Reports Server (NTRS)

Bushnell, Dennis

1990-01-01

Initial disturbance fields are categorized and discussed with respect to modes of disturbance and the variants which occur for each test technique. Attention is focused on four fluctuation modes included under the category of stream turbulence: vorticity fluctuations, entropy disturbances or temperature spottiness, noise, and concentration fluctuations. The mechanisms by which particulate matter can affect transition are discussed, along with electrostatic discharges with frequencies in the range from 200 KHz to 30 MHz which is within the critical disturbance-frequency range for many high-speed flows. Acoustic radiation from own vehicle, roughness, and Brownian motion are also covered.

A simple LC-MS/MS method using HILIC chromatography for the determination of fosfomycin in plasma and urine: application to a pilot pharmacokinetic study in humans.

PubMed

Parker, Suzanne L; Lipman, Jeffrey; Roberts, Jason A; Wallis, Steven C

2015-02-01

A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, using hydrophilic interaction liquid chromatography (HILIC) chromatography for the analysis of fosfomycin in human plasma and urine, has been developed and validated. The plasma method uses a simple protein precipitation using a low volume sample (10 μL) and is suitable for the concentration range of 1 to 2000 μg/mL. The urine method involves a simple dilution of 10 μL of sample and is suitable for a concentration range of 0.1 to 10 mg/mL. The plasma and urine results, reported, respectively, are for recovery (68, 72%), inter-assay precision (≤9.1%, ≤8.1%) and accuracy (range -7.2 to 3.3%, -1.9 to 1.6%), LLOQ precision (4.7%, 3.1%) and accuracy (1.7% and 1.2%), and includes investigations into the linearity, stability and matrix effects. The method was used in a pilot pharmacokinetic study of a critically ill patient receiving i.v. fosfomycin, which measured a maximum and minimum plasma concentration of 222 μg/mL and 172 μg/mL, respectively, after the initial dose, and a maximum and minimum plasma concentration of 868 μg/mL and 591μg/mL, respectively, after the fifth dose. The urine concentration was 2.03 mg/mL after the initial dose and 0.29 mg/mL after the fifth dose. Copyright © 2014 Elsevier B.V. All rights reserved.

Tricyclic Antidepressants

NASA Astrophysics Data System (ADS)

Schmidt, Gary J.

The use of tricyclic antidepressant drugs is becoming increasingly prevalent for the treatment of depressed patients. It has been suggested that, analogous to many other drug substances, the tricyclic drugs exhibit clinical effectiveness within a defined therapeutic concentration range (1-10). Very recently, both Dito (11) and Orsulak and Schildkraut (12) have summarized the usefulness of measuring serum concentrations of these drugs. These authors suggest that knowledge of the plasma concentrations of these drugs aid the physician in determining patient compliance and initiating the best possible drug treatment.

Vancomycin AUC/MIC and Corresponding Troughs in a Pediatric Population

PubMed Central

Lardieri, Allison B.; Heil, Emily L.; Morgan, Jill A.

2017-01-01

OBJECTIVES Adult guidelines suggest an area under the curve/minimum inhibitory concentration (AUC/MIC) > 400 corresponds to a vancomycin trough serum concentration of 15 to 20 mg/L for methicillin-resistant Staphylococcus aureus infections, but obtaining these troughs in children are difficult. The primary objective of this study was to assess the likelihood that 15 mg/kg of vancomycin every 6 hours in a child achieves an AUC/MIC > 400. METHODS This retrospective chart review included pediatric patients >2 months to <18 years with a positive S aureus blood culture and documented MIC who received at least two doses of vancomycin with corresponding trough. Patients were divided into two groups: group 1 initially receiving ≥15 mg/kg every 6 hours, and group 2 initially receiving any other dosing ranges or intervals. AUCs were calculated four times using three pharmacokinetic methods. RESULTS A total of 36 patients with 99 vancomycin trough serum concentrations were assessed. Baseline characteristics were similar between groups. For troughs in group 1 (n = 55), the probability of achieving an AUC/MIC > 400 ranged from 16.4% to 90.9% with a median trough concentration of 11.4 mg/L, while in group 2 (n = 44) the probability of achieving AUC/MIC > 400 ranged from 15.9% to 54.5% with mean trough concentration of 9.2 mg/L. The AUC/MICs were not similar between the different pharmacokinetic methods used; however, a trapezoidal equation (Method A) yielded the highest correlation coefficient (r2 = 0.59). When dosing every 6 hours, an AUC/MIC of 400 correlated to a trough serum concentration of 11 mg/L. CONCLUSIONS The probability of achieving an AUC/MIC > 400 using only a trough serum concentration and an MIC with patients receiving 15 mg/kg every 6 hours is variable based on the method used to calculate the AUC. An AUC/MIC of 400 in children correlated to a trough concentration of 11 mg/L using a trapezoidal Method to calculate AUC. PMID:28337080

Vancomycin AUC/MIC and Corresponding Troughs in a Pediatric Population.

PubMed

Kishk, Omayma A; Lardieri, Allison B; Heil, Emily L; Morgan, Jill A

2017-01-01

Adult guidelines suggest an area under the curve/minimum inhibitory concentration (AUC/MIC) > 400 corresponds to a vancomycin trough serum concentration of 15 to 20 mg/L for methicillin-resistant Staphylococcus aureus infections, but obtaining these troughs in children are difficult. The primary objective of this study was to assess the likelihood that 15 mg/kg of vancomycin every 6 hours in a child achieves an AUC/MIC > 400. This retrospective chart review included pediatric patients >2 months to <18 years with a positive S aureus blood culture and documented MIC who received at least two doses of vancomycin with corresponding trough. Patients were divided into two groups: group 1 initially receiving ≥15 mg/kg every 6 hours, and group 2 initially receiving any other dosing ranges or intervals. AUCs were calculated four times using three pharmacokinetic methods. A total of 36 patients with 99 vancomycin trough serum concentrations were assessed. Baseline characteristics were similar between groups. For troughs in group 1 (n = 55), the probability of achieving an AUC/MIC > 400 ranged from 16.4% to 90.9% with a median trough concentration of 11.4 mg/L, while in group 2 (n = 44) the probability of achieving AUC/MIC > 400 ranged from 15.9% to 54.5% with mean trough concentration of 9.2 mg/L. The AUC/MICs were not similar between the different pharmacokinetic methods used; however, a trapezoidal equation (Method A) yielded the highest correlation coefficient (r 2 = 0.59). When dosing every 6 hours, an AUC/MIC of 400 correlated to a trough serum concentration of 11 mg/L. The probability of achieving an AUC/MIC > 400 using only a trough serum concentration and an MIC with patients receiving 15 mg/kg every 6 hours is variable based on the method used to calculate the AUC. An AUC/MIC of 400 in children correlated to a trough concentration of 11 mg/L using a trapezoidal Method to calculate AUC.

Equilibrium and kinetic modelling of chromium(III) sorption by animal bones.

PubMed

Chojnacka, Katarzyna

2005-04-01

The paper discusses sorption of Cr(III) ions from aqueous solutions by animal bones. Animal bones were found to be an efficient sorbent with the maximum experimentally determined sorption capacity in the range 29-194 mg g(-1) that depended on pH and temperature. The maximum experimentally determined sorption capacity was obtained at 50 degrees C, pH 5. Batch kinetics and equilibrium experiments were performed in order to investigate the influence of contact time, initial concentration of sorbate and sorbent, temperature and pH. It was found that sorption capacity increased with increase of Cr(III) concentration, temperature and initial pH of metal solution. Mathematical models describing kinetics and statics of sorption were proposed. It was found that process kinetics followed the pseudo-second-order pattern. The influence of sorbent concentration was described with Langmuir-type equation and the influence of sorbate concentration was described with empirical dependence. The models were positively verified.

Applying Dispersive Changes to Lagrangian Particles in Groundwater Transport Models

USGS Publications Warehouse

Konikow, Leonard F.

2010-01-01

Method-of-characteristics groundwater transport models require that changes in concentrations computed within an Eulerian framework to account for dispersion be transferred to moving particles used to simulate advective transport. A new algorithm was developed to accomplish this transfer between nodal values and advecting particles more precisely and realistically compared to currently used methods. The new method scales the changes and adjustments of particle concentrations relative to limiting bounds of concentration values determined from the population of adjacent nodal values. The method precludes unrealistic undershoot or overshoot for concentrations of individual particles. In the new method, if dispersion causes cell concentrations to decrease during a time step, those particles in the cell having the highest concentration will decrease the most, and those with the lowest concentration will decrease the least. The converse is true if dispersion is causing concentrations to increase. Furthermore, if the initial concentration on a particle is outside the range of the adjacent nodal values, it will automatically be adjusted in the direction of the acceptable range of values. The new method is inherently mass conservative. ?? US Government 2010.

Applying dispersive changes to Lagrangian particles in groundwater transport models

USGS Publications Warehouse

Konikow, Leonard F.

2010-01-01

Method-of-characteristics groundwater transport models require that changes in concentrations computed within an Eulerian framework to account for dispersion be transferred to moving particles used to simulate advective transport. A new algorithm was developed to accomplish this transfer between nodal values and advecting particles more precisely and realistically compared to currently used methods. The new method scales the changes and adjustments of particle concentrations relative to limiting bounds of concentration values determined from the population of adjacent nodal values. The method precludes unrealistic undershoot or overshoot for concentrations of individual particles. In the new method, if dispersion causes cell concentrations to decrease during a time step, those particles in the cell having the highest concentration will decrease the most, and those with the lowest concentration will decrease the least. The converse is true if dispersion is causing concentrations to increase. Furthermore, if the initial concentration on a particle is outside the range of the adjacent nodal values, it will automatically be adjusted in the direction of the acceptable range of values. The new method is inherently mass conservative.

Uptake and biotransformation of 2,4,6-trinitrotoluene (TNT) by microplantlet suspension culture of the marine red macroalga Portieria hornemannii.

PubMed

Cruz-Uribe, Octavio; Rorrer, Gregory L

2006-02-20

Microplantlets of the marine red macroalga Portieria hornemannii efficiently removed the explosive compound 2,4,6-trinitrotoluene (TNT) from seawater. Photosynthetic, axenic microplantlets (1.2 g FW/L) were challenged with enriched seawater medium containing dissolved TNT at concentrations of 1.0, 10, and 50 mg/L. At 22 degrees C and initial TNT concentrations of 10 mg/L or less, TNT removal from seawater was 100% within 72 h, and the first-order rate constant for TNT removal ranged from 0.025 to 0.037 L/gFW h under both illuminated conditions (153 microE/m(2)s, 14:10 LD photoperiod) and dark conditions. Two immediate products of TNT biotransformation, 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dintrotoluene, were identified in the liquid culture medium, with a maximum material balance recovery of 29 mole%. Only trace levels of these products and residual TNT were found within the fresh cell biomass. Removal of TNT by P. hornemannii microplantlets at initial concentrations of 1.0 or 10 mg/L did not affect the respiration rate. At an initial TNT concentration of 10 mg/L, net photosynthesis decreased towards zero, commensurate with the removal of dissolved TNT from seawater, whereas at an initial TNT concentration of 1.0 mg/L, the net photosynthesis rate was not affected. Copyright 2005 Wiley Periodicals, Inc.

Dechlorination of trichloroethylene formed from 1,1,2,2-tetrachloroethane by dehydrochlorination in Portland cement slurry including Fe(II).

PubMed

Jung, Bahngmi; Batchelor, Bill

2008-03-01

Transformation of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) by Fe(II) in 10% cement slurries was characterized using a batch reactor system. 1,1,2,2-TeCA was completely converted to trichloroethylene (TCE) within 1h in all experiments, even in controls with cement that did not include Fe(II). Therefore, complete degradation of 1,1,2,2-TeCA depends on the behavior of TCE. The half-life of TCE was observed to be 15d when concentrations of Fe(II) and 1,1,2,2-TeCA were 98mM and 0.245mM, respectively. The kinetics of TCE removal was observed to be dependent on Fe(II) dose, pH and initial substrate concentration. Pseudo-first-order rate constants linearly increased with Fe(II) dose up to 198mM when initial target concentration was 0.245mM. Pseudo-first-order kinetics generally described the degradation reactions of TCE at a specific initial concentration, but a modified Langmuir-Hinshelwood model was necessary to describe the degradation kinetics of TCE over a wide range of initial concentrations. A surface reaction of TCE on active solids, which were formed from Fe(II) and products of cement hydration appears to control observed TCE degradation kinetics.

Decay model for biocide treatment of unballasted vessels: application for the Laurentian Great Lakes.

PubMed

Sano, Larissa L; Bartell, Steven M; Landrum, Peter F

2005-10-01

A biocide decay model was developed to assess the potential efficacy and environmental impacts associated with using glutaraldehyde to treat unballasted overseas vessels trading on the Laurentian Great Lakes. The results of Monte Carlo simulations indicate that effective glutaraldehyde concentrations can be maintained for the duration of a vessel's oceanic transit (approximately 9-12 days): During this transit, glutaraldehyde concentrations were predicted to decrease by approximately 10% from initial treatment levels (e.g., 500 mgL(-1)). In terms of environmental impacts, mean glutaraldehyde concentrations released at Duluth-Superior Harbor, MN were predicted to be 100-fold lower than initial treatment concentrations, and ranged from 3.2 mgL(-1) (2 SD: 2.74) in April to 0.7 mgL(-1) (2 SD: 1.28) in August. Sensitivity analyses indicated that the re-ballasting dilution factor was the major variable governing final glutaraldehyde concentrations; however, lake surface temperatures became increasingly important during the warmer summer months.

A novel public health threat - high lead solder in stainless steel rainwater tanks in Tasmania.

PubMed

Lodo, Kerryn; Dalgleish, Cameron; Patel, Mahomed; Veitch, Mark

2018-02-01

We identified two water tanks in Tasmania with water lead concentrations exceeding the Australian Drinking Water Guidelines (ADWG) limit; they had been constructed with stainless steel and high-lead solder from a single manufacturer. An investigation was initiated to identify all tanks constructed by this manufacturer and prevent further exposure to contaminated water. To identify water tanks we used sales accounts, blood and water lead results from laboratories, and media. We analysed blood and water lead concentration results from laboratories and conducted a nested cohort study of blood lead concentrations in children aged <18 years. We identifed 144 tanks constructed from stainless steel and high lead solder. Median water lead concentrations were significantly higher in the stainless steel tanks (121µg/L) than in the galvanised tanks (1µg/L). Blood lead concentrations ranged from 1 to 26µg/dL (median 5µg/dL); of these, 77% (n=50) were below the then-recommended health-related concentration of 10µg/dL. Concentrations in the 15 people (23%) above this limit ranged from 10-26µg/dL, with a median of 14µg/dL. The median blood lead concentration in the nested cohort of children was initially 8.5µg/dL, dropping to 4.5µg/dL after follow-up. Lead concentrations in the water tanks constructed from stainless steel and high-lead solder were up to 200 times above the recommended ADWG limits. Implications for public health: This investigation highlights the public health risk posed by use of non-compliant materials in constructing water tanks. © 2017 Department of Health and Human Services Tasmania.

Development and Optimization of HPLC Analysis of Metronidazole, Diloxanide, Spiramycin and Cliquinol in Pharmaceutical Dosage Forms Using Experimental Design.

PubMed

Elkhoudary, Mahmoud M; Abdel Salam, Randa A; Hadad, Ghada M

2016-11-01

A new simple, sensitive, rapid and accurate gradient reversed-phase high-performance liquid chromatography with photodiode array detector (RP-HPLC-DAD) was developed and validated for simultaneous analysis of Metronidazole (MNZ), Spiramycin (SPY), Diloxanidefuroate (DIX) and Cliquinol (CLQ) using statistical experimental design. Initially, a resolution V fractional factorial design was used in order to screen five independent factors: the column temperature (°C), pH, phosphate buffer concentration (mM), flow rate (ml/min) and the initial fraction of mobile phase B (%). pH, flow rate and initial fraction of mobile phase B were identified as significant, using analysis of variance. The optimum conditions of separation determined with the aid of central composite design were: (1) initial mobile phase concentration: phosphate buffer/methanol (50/50, v/v), (2) phosphate buffer concentration (50 mM), (3) pH (4.72), (4) column temperature 30°C and (5) mobile phase flow rate (0.8 ml min -1 ). Excellent linearity was observed for all of the standard calibration curves, and the correlation coefficients were above 0.9999. Limits of detection for all of the analyzed compounds ranged between 0.02 and 0.11 μg ml -1 ; limits of quantitation ranged between 0.06 and 0.33 μg ml -1 The proposed method showed good prediction ability. The optimized method was validated according to ICH guidelines. Three commercially available tablets were analyzed showing good % recovery and %RSD. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[Evaluation of the influence of humidity and temperature on the drug stability by initial average rate experiment].

PubMed

He, Ning; Sun, Hechun; Dai, Miaomiao

2014-05-01

To evaluate the influence of temperature and humidity on the drug stability by initial average rate experiment, and to obtained the kinetic parameters. The effect of concentration error, drug degradation extent, humidity and temperature numbers, humidity and temperature range, and average humidity and temperature on the accuracy and precision of kinetic parameters in the initial average rate experiment was explored. The stability of vitamin C, as a solid state model, was investigated by an initial average rate experiment. Under the same experimental conditions, the kinetic parameters obtained from this proposed method were comparable to those from classical isothermal experiment at constant humidity. The estimates were more accurate and precise by controlling the extent of drug degradation, changing humidity and temperature range, or by setting the average temperature closer to room temperature. Compared with isothermal experiments at constant humidity, our proposed method saves time, labor, and materials.

Indoor transient SOA formation from ozone + α-pinene reactions: Impacts of air exchange and initial product concentrations, and comparison to limonene ozonolysis

NASA Astrophysics Data System (ADS)

Youssefi, Somayeh; Waring, Michael S.

2015-07-01

The ozonolysis of reactive organic gases (ROG), e.g. terpenes, generates secondary organic aerosol (SOA) indoors. The SOA formation strength of such reactions is parameterized by the aerosol mass fraction (AMF), a.k.a. SOA yield, which is the mass ratio of generated SOA to oxidized ROG. AMFs vary in magnitude both among and for individual ROGs. Here, we quantified dynamic SOA formation from the ozonolysis of α-pinene with 'transient AMFs,' which describe SOA formation due to pulse emission of a ROG in an indoor space with air exchange, as is common when consumer products are intermittently used in ventilated buildings. We performed 19 experiments at low, moderate, and high (0.30, 0.52, and 0.94 h-1, respectively) air exchange rates (AER) at varying concentrations of initial reactants. Transient AMFs as a function of peak SOA concentrations ranged from 0.071 to 0.25, and they tended to increase as the AER and product of the initial reactant concentrations increased. Compared to our similar research on limonene ozonolysis (Youssefi and Waring, 2014), for which formation strength was driven by secondary ozone reactions, the AER impact for α-pinene was opposite in direction and weaker, while the initial reactant product impact was in the same direction but stronger for α-pinene than for limonene. Linear fits of AMFs for α-pinene ozonolysis as a function of the AER and initial reactant concentrations are provided so that future indoor models can predict SOA formation strength.

Atmospheric Concentrations of New Persistent Organic Pollutants and Emerging Chemicals of Concern in the Group of Latin America and Caribbean (GRULAC) Region.

PubMed

Rauert, Cassandra; Harner, Tom; Schuster, Jasmin K; Eng, Anita; Fillmann, Gilberto; Castillo, Luisa Eugenia; Fentanes, Oscar; Villa Ibarra, Martín; Miglioranza, Karina S B; Moreno Rivadeneira, Isabel; Pozo, Karla; Aristizábal Zuluaga, Beatriz Helena

2018-06-15

A special initiative was run by the Global Atmospheric Passive Sampling (GAPS) Network to provide atmospheric data on a range of emerging chemicals of concern and candidate and new persistent organic pollutants in the Group of Latin America and Caribbean (GRULAC) region. Regional-scale data for a range of flame retardants (FRs) including polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs), and a range of alternative FRs (novel FRs) are reported over 2 years of sampling with low detection frequencies of the novel FRs. Atmospheric concentrations of the OPEs were an order of magnitude higher than all other FRs, with similar profiles at all sites. Regional-scale background concentrations of the poly- and perfluoroalkyl substances (PFAS), including the neutral PFAS (n-PFAS) and perfluoroalkyl acids (PFAAs), and the volatile methyl siloxanes (VMS) are also reported. Ethyl perfluorooctane sulfonamide (EtFOSA) was detected at highly elevated concentrations in Brazil and Colombia, in line with the use of the pesticide sulfluramid in this region. Similar concentrations of the perfluoroalkyl sulfonates (PFAS) were detected throughout the GRULAC region regardless of location type, and the VMS concentrations in air increased with the population density of sampling locations. This is the first report of atmospheric concentrations of the PFAAs and VMS from this region.

Concentration dependence of biotransformation in fish liver S9: Optimizing substrate concentrations to estimate hepatic clearance for bioaccumulation assessment.

PubMed

Lo, Justin C; Allard, Gayatri N; Otton, S Victoria; Campbell, David A; Gobas, Frank A P C

2015-12-01

In vitro bioassays to estimate biotransformation rate constants of contaminants in fish are currently being investigated to improve bioaccumulation assessments of hydrophobic contaminants. The present study investigates the relationship between chemical substrate concentration and in vitro biotransformation rate of 4 environmental contaminants (9-methylanthracene, pyrene, chrysene, and benzo[a]pyrene) in rainbow trout (Oncorhynchus mykiss) liver S9 fractions and methods to determine maximum first-order biotransformation rate constants. Substrate depletion experiments using a series of initial substrate concentrations showed that in vitro biotransformation rates exhibit strong concentration dependence, consistent with a Michaelis-Menten kinetic model. The results indicate that depletion rate constants measured at initial substrate concentrations of 1 μM (a current convention) could underestimate the in vitro biotransformation potential and may cause bioconcentration factors to be overestimated if in vitro biotransformation rates are used to assess bioconcentration factors in fish. Depletion rate constants measured using thin-film sorbent dosing experiments were not statistically different from the maximum depletion rate constants derived using a series of solvent delivery-based depletion experiments for 3 of the 4 test chemicals. Multiple solvent delivery-based depletion experiments at a range of initial concentrations are recommended for determining the concentration dependence of in vitro biotransformation rates in fish liver fractions, whereas a single sorbent phase dosing experiment may be able to provide reasonable approximations of maximum depletion rates of very hydrophobic substances. © 2015 SETAC.

Fate of the pyrethroid insecticide deltamethrin in small ponds: a mass balance study

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

Muir, D.C.G.; Rawn, G.P.; Grift, N.P.

The fate and distribution of /sup 14/C-radiolabeled deltamethrin (1(R)(la(S),3a)-cyano-(3-phenoxyphenyl)methyl 3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate) were monitored for 306 days, following a single application at 10 g/ha to two small outdoor ponds (17 m/sup 2/ surface area). Initial concentrations of the insecticide in filtered water ranged from 1.28 to 2.50 ..mu..g/L. Deltamethrin ((/sup 14/C)cyclopropyl acid or benzyl alcohol labeled) rapidly partitioned into suspended solids, plants, sediment, and air, with a half-life of 2-4 h in water. Duckweed (Lemna sp.) and a submerged pondweed (Potamogeton berchtoldi) accumulated deltamethrin concentrations ranging from 253 to 1021 ng/g, respectively, at 24 h posttreatment. Sediments were the major sink formore » radioactivity at 306 days posttreatment, and intact deltamethrin was present at concentrations ranging from 3 to 5 ng/g. Deltamethrin levels in air above the water ranged from 10-100 ng/m/sup 3/ during a 48-h monitoring period following application. Fathead minnows (Pimephales promelas) accumulated levels of extractable radioactivity 248-907-fold higher than concentrations in water 24 h posttreatment, but no fish mortality was observed.« less

Evaluation of serum biochemical marker concentrations and survival time in dogs with protein-losing enteropathy.

PubMed

Equilino, Mirjam; Théodoloz, Vincent; Gorgas, Daniela; Doherr, Marcus G; Heilmann, Romy M; Suchodolski, Jan S; Steiner, Jörg M; Burgener Dvm, Iwan A

2015-01-01

To evaluate serum concentrations of biochemical markers and survival time in dogs with protein-losing enteropathy (PLE). Prospective study. 29 dogs with PLE and 18 dogs with food-responsive diarrhea (FRD). Data regarding serum concentrations of various biochemical markers at the initial evaluation were available for 18 of the 29 dogs with PLE and compared with findings for dogs with FRD. Correlations between biochemical marker concentrations and survival time (interval between time of initial evaluation and death or euthanasia) for dogs with PLE were evaluated. Serum C-reactive protein concentration was high in 13 of 18 dogs with PLE and in 2 of 18 dogs with FRD. Serum concentration of canine pancreatic lipase immunoreactivity was high in 3 dogs with PLE but within the reference interval in all dogs with FRD. Serum α1-proteinase inhibitor concentration was less than the lower reference limit in 9 dogs with PLE and 1 dog with FRD. Compared with findings in dogs with FRD, values of those 3 variables in dogs with PLE were significantly different. Serum calprotectin (measured by radioimmunoassay and ELISA) and S100A12 concentrations were high but did not differ significantly between groups. Seventeen of the 29 dogs with PLE were euthanized owing to this disease; median survival time was 67 days (range, 2 to 2,551 days). Serum C-reactive protein, canine pancreatic lipase immunoreactivity, and α1-proteinase inhibitor concentrations differed significantly between dogs with PLE and FRD. Most initial biomarker concentrations were not predictive of survival time in dogs with PLE.

Methods to validate the accuracy of an indirect calorimeter in the in-vitro setting.

PubMed

Oshima, Taku; Ragusa, Marco; Graf, Séverine; Dupertuis, Yves Marc; Heidegger, Claudia-Paula; Pichard, Claude

2017-12-01

The international ICALIC initiative aims at developing a new indirect calorimeter according to the needs of the clinicians and researchers in the field of clinical nutrition and metabolism. The project initially focuses on validating the calorimeter for use in mechanically ventilated acutely ill adult patient. However, standard methods to validate the accuracy of calorimeters have not yet been established. This paper describes the procedures for the in-vitro tests to validate the accuracy of the new indirect calorimeter, and defines the ranges for the parameters to be evaluated in each test to optimize the validation for clinical and research calorimetry measurements. Two in-vitro tests have been defined to validate the accuracy of the gas analyzers and the overall function of the new calorimeter. 1) Gas composition analysis allows validating the accuracy of O 2 and CO 2 analyzers. Reference gas of known O 2 (or CO 2 ) concentration is diluted by pure nitrogen gas to achieve predefined O 2 (or CO 2 ) concentration, to be measured by the indirect calorimeter. O 2 and CO 2 concentrations to be tested were determined according to their expected ranges of concentrations during calorimetry measurements. 2) Gas exchange simulator analysis validates O 2 consumption (VO 2 ) and CO 2 production (VCO 2 ) measurements. CO 2 gas injection into artificial breath gas provided by the mechanical ventilator simulates VCO 2 . Resulting dilution of O 2 concentration in the expiratory air is analyzed by the calorimeter as VO 2 . CO 2 gas of identical concentration to the fraction of inspired O 2 (FiO 2 ) is used to simulate identical VO 2 and VCO 2 . Indirect calorimetry results from publications were analyzed to determine the VO 2 and VCO 2 values to be tested for the validation. O 2 concentration in respiratory air is highest at inspiration, and can decrease to 15% during expiration. CO 2 concentration can be as high as 5% in expired air. To validate analyzers for measurements of FiO 2 up to 70%, ranges of O 2 and CO 2 concentrations to be tested were defined as 15-70% and 0.5-5.0%, respectively. The mean VO 2 in 426 adult mechanically ventilated patients was 270 ml/min, with 2 standard deviation (SD) ranges of 150-391 ml/min. Thus, VO 2 and VCO 2 to be simulated for the validation were defined as 150, 250, and 400 ml/min. The procedures for the in-vitro tests of the new indirect calorimeter and the ranges for the parameters to be evaluated in each test have been defined to optimize the validation of accuracy for clinical and research indirect calorimetry measurements. The combined methods will be used to validate the accuracy of the new indirect calorimeter developed by the ICALIC initiative, and should become the standard method to validate the accuracy of any future indirect calorimeters. Copyright © 2017 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

Solute partitioning under continuous cooling conditions as a cooling rate indicator. [in lunar rocks

NASA Technical Reports Server (NTRS)

Onorato, P. I. K.; Hopper, R. W.; Yinnon, H.; Uhlmann, D. R.; Taylor, L. A.; Garrison, J. R.; Hunter, R.

1981-01-01

A model of solute partitioning in a finite body under conditions of continuous cooling is developed for the determination of cooling rates from concentration profile data, and applied to the partitioning of zirconium between ilmenite and ulvospinel in the Apollo 15 Elbow Crater rocks. Partitioning in a layered composite solid is described numerically in terms of concentration profiles and diffusion coefficients which are functions of time and temperature, respectively; a program based on the model can be used to calculate concentration profiles for various assumed cooling rates given the diffusion coefficients in the two phases and the equilibrium partitioning ratio over a range of temperatures. In the case of the Elbow Rock gabbros, the cooling rates are calculated from measured concentration ratios 10 microns from the interphase boundaries under the assumptions of uniform and equilibrium initial conditions at various starting temperatures. It is shown that the specimens could not have had uniform concentrations profiles at the previously suggested initial temperature of 1350 K. It is concluded that even under conditions where the initial temperature, grain sizes and solute diffusion coefficients are not well characterized, the model can be used to estimate the cooling rate of a grain assemblage to within an order of magnitude.

Decomposition of 2,4,6-trinitrotoluene (TNT) by gamma irradiation.

PubMed

Lee, Byungjin; Lee, Myunjoo

2005-12-01

The purpose of this study was to evaluate the potential of gamma irradiation to decompose 2,4,6-trinitrotoluene (TNT) in an aqueous solution; the concentration range of the TNT solution was 0.11-0.44 mmol/L. The decomposition rate of TNT by gamma irradiation was pseudo-first-order kinetic over the applied initial concentrations. The dose constant was strongly dependent on the initial concentration of TNT. Increasing the concentration of dissolved oxygen in the solution was more effective on the decomposition of TNT as well as its mineralization. The required irradiation dose to remove 90% of initial TNT (0.44 mmol/L) was 58, 41, 32, 28, and 25 kGy at the dissolved oxygen concentration of 0.025, 0.149, 0.3, 0.538, and 0.822 mmol/L, respectively. However, TOC still remained as 30% of the initial TOC (3.19 mmol/L) when 200 kGy irradiation dose was applied to the TNT solution (0.44 mmol/L) containing dissolved oxygen of 0.822 mmol/L. The removal of the TNT was more efficient at a pH below 3 and at a pH above 11 than at neutral pH (pH 5-9). The required irradiation dose to remove over 99% of the initial TNT (0.44 mmol/L) was 39, 76, and 10 kGy at pH 2, 7, and 13, respectively. The dose constant was increased 1.6-fold and over 15.6-fold at pH 2 and 13, respectively, compared to that at pH 7. When an irradiation dose of 200 kGy was applied, the removal efficiencies of the TOC (initial concentration 3.19 mmol/L) were 91, 46, and 53% at pH 2, 7, and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of TNT, and glyoxalic acid and oxalic acid were detected as organic byproducts.

Cometabolic biodegradation of trichloroethylene in microcosms

USGS Publications Warehouse

Kane, Allen C.; Wilson, Timothy P.; Fischer, Jeffrey M.

1997-01-01

Laboratory microcosms were used to determine the concentrations of oxygen (O2) and methane (CH4) that optimize trichloroethylene (TCE) biodegradation in sediment and ground-water samples from a TCE-contaminated aquifer at Picatinny Arsenal, Morris County, New Jersey. The mechanism for degradation is the cometabolic activity of methanotrophic bacteria. The laboratory data will be used to support a field study designed to demonstrate the effectiveness of combining air sparging with cometabolic degradation of TCE for the purpose of aquifer remediation. Microcosms were constructed in autoclaved 250-mL (milliliter) amber glass bottles with valves for repeated headspace sampling. Equal volumes (25 mL) of sediment and ground water, collected from a depth of 40 feet, were added. TCE was added to attain initial aqueous concentrations equal to the field level of 1,400 mu g/L (micrograms per liter). Nine microcosms were constructed with initial headspace O2 concentrations of 5%, 10%, or 14% and CH4 concentrations of 0.5%, 3%, or 5%, with nitrogen making up the balance. Sterile controls, controls without CH4, and controls without sediment were also constructed. A 4-mL gas sample was removed periodically and TCE, O2 , CH4 , and carbon dioxide (CO2) concentrations were measured by using gas chromatography. As biodegradation proceeded, the decrease in O2, CH4 , and TCE concentrations and the production of CO2 were monitored. An initial acclimation period of at least 100 days was observed in those microcosms in which significant microbial activity occurred, as determined from decreases in O2 and CH4 concentrations and an increase in CO2 content. Degradation of TCE occurred with O2 concentrations of 2.7 to 8.7% and CH4 concentrations of 0.5 to 3.5%. Microcosms that initially contained 10% O2 and 3% CH4 showed the greatest microbial activity and the greatest amount of TCE degradation. The greatest rates of TCE degradation occurred when O2 and CH4 headspace concentrations reached levels of 7.7 to 8.7% and 1.7 to 2.7%, respectively, which correspond to aqueous concentrations of 2.9 to 3.5 mg/L and 0.4 to 0.6 mg/L, respectively. Over these ranges, TCE degradation rates ranged from 15 to 20 mu g of TCE per kilogram of sediment per day. Analysis of the control microcosms indicated that these TCE degradation rates are much greater than those attributable to experimental variation. The results indicate that the microbial community of the sediment is capable of TCE degradation and that significant rates of degradation can be achieved with obtainable O2 and CH4 concentrations.

The effect of processing parameters and solid concentration on the mechanical and microstructural properties of freeze-casted macroporous hydroxyapatite scaffolds.

PubMed

Farhangdoust, S; Zamanian, A; Yasaei, M; Khorami, M

2013-01-01

The design and fabrication of macroporous hydroxyapatite scaffolds, which could overcome current bone tissue engineering limitations, have been considered in recent years. In the current study, controlled unidirectional freeze-casting at different cooling rates was investigated. In the first step, different slurries with initial hydroxyapatite concentrations of 7-37.5 vol.% were prepared. In the next step, different cooling rates from 2 to 14 °C/min were applied to synthesize the porous scaffold. Additionally, a sintering temperature of 1350 °C was chosen as an optimum temperature. Finally, the phase composition (by XRD), microstructure (by SEM), mechanical characteristics, and the porosity of sintered samples were assessed. The porosity of the sintered samples was in a range of 45-87% and the compressive strengths varied from 0.4 MPa to 60 MPa. The mechanical strength of the scaffolds increased as a function of initial concentration, cooling rate, and sintering temperature. With regards to mechanical strength and pore size, the samples with the initial concentration and the cooling rate of 15 vol.% and 5 °C/min, respectively, showed better results. Copyright © 2012 Elsevier B.V. All rights reserved.

A differential absorption lidar instrument for the measurment of carbon dioxide and methane in the lower troposphere (Conference Presentation)

NASA Astrophysics Data System (ADS)

Budinov, Daniel; Clements, Robert; Rae, Cameron F.; Moncrieff, John B.; Jack, James W.

2016-12-01

Developments in the remote detection of trace gases in the atmosphere using Differential Absorption Lidar have been driven largely by improvements in two key technologies: lasers and detectors. We have designed and built a narrow linewidth pulsed laser source with a well-controlled output wavelength and sufficient pulse energy to measure the concentration profile of CO2 and CH4 to a range in excess of 4km. We describe here the initial measurements of concentration profiles recorded with this instrument. The system is built around a custom-designed Newtonian telescope with a 40cm diameter primary mirror. Laser sources and detectors attach directly to the side of the telescope allowing for flexible customization with a range of additional equipment. The instrument features an all-solid-state laser source based on an optical parametric oscillator (OPO) pumped by an YLF based diode-laser pumped solid-state laser and seeded by a tuned DFB seed. This provides a range of available wavelengths suitable for DIAL within the 1.5-1.6 μm spectral region. The output of the OPO is beam expanded and transmitted coaxially from the receiver telescope. A gas cell within the laser source controls the seed wavelength and allows the wavelength to be tuned to match a specific absorption feature of the selected gas species. The source can be rapidly tuned between the on-line and off-line wavelengths to make a DIAL measurement of either CO2 or CH4 The receiver is based on an InGaAs avalanche photodetector. Whilst photodiode detectors are a low-cost solution their limited sensitivity restricts the maximum range over which a signal can be detected. The receiver signal is digitised for subsequent processing to produce a sightline concentration profile. The instrument is mounted on a robust gimballed mount providing full directional movement within the upper hemisphere. Both static pointing and angular scan modes are available. Accurate angular position is available giving the sightline vector and supporting the interpretation of the concentration profile. Initial measurements have been made in the planetary boundary layer above the City of Edinburgh and these will be presented and discussed. Earlier measurements demonstrated that the signal from atmospheric scatter could be detected at ranges in excess of 6km. The later measurements have shown scatter signals at greater ranges, but with increasing noise at the longer ranges. This is expected as the signal decreases with the inverse of the range whereas the noise remains effectively constant. Range resolved concentration profiles for sightline vectors lying within an angular sector have been used to create a 3D map of concentration for that volume. This will be presented and discussed.

Microbial Successions and Metabolite Changes during Fermentation of Salted Shrimp (Saeu-Jeot) with Different Salt Concentrations

PubMed Central

Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

2014-01-01

To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot. PMID:24587230

Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

USGS Publications Warehouse

Stohlgren, Thomas J.

1988-01-01

The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p < 0.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

Investigation of hexavalent chromium sorption in serpentine sediments

NASA Astrophysics Data System (ADS)

Mpouras, Thanasis; Chrysochoou, Maria; Dermatas, Dimitris

2017-02-01

In this study the removal of hexavalent chromium (Cr6 +) by serpentine sediments was investigated in order to delineate Cr6 + sorption behavior in aquifers with ultramafic geologic background. Batch experiments were conducted in order to determine the influence of several parameters on Cr6 + removal, including the pH of the sediment solution, mineralogy, sediment's particle size and Cr6 + initial concentration. The results showed that Cr6 + removal was due to both adsorption and reduction phenomena. Reduction was attributed to the presence of a magnetic fraction in the sediment, mostly related to magnetite, which contributed almost 50% of the total removal in the pH range 3-7. Adsorption behavior was dominated by the finer sediment fraction (d < 0.075 mm). The amount of Cr6 + adsorbed was constant in the pH range 3-7, while it decreased sharply in the range 7-8.5. Cr6 + adsorption was found to increase and decrease proportionally with increasing initial Cr6 + concentration of and particle size, respectively. The linear Langmuir and Freundlich adsorption isotherms were used to describe the experimental data, with Freundlich providing a better fit to determine distribution factors for transport modeling.

Mathematical modeling of the ethanol fermentation of cashew apple juice by a flocculent yeast: the effect of initial substrate concentration and temperature.

PubMed

Pinheiro, Álvaro Daniel Teles; da Silva Pereira, Andréa; Barros, Emanuel Meneses; Antonini, Sandra Regina Ceccato; Cartaxo, Samuel Jorge Marques; Rocha, Maria Valderez Ponte; Gonçalves, Luciana Rocha B

2017-08-01

In this work, the effect of initial sugar concentration and temperature on the production of ethanol by Saccharomyces cerevisiae CCA008, a flocculent yeast, using cashew apple juice in a 1L-bioreactor was studied. The experimental results were used to develop a kinetic model relating biomass, ethanol production and total reducing sugar consumption. Monod, Andrews, Levenspiel and Ghose and Tyagi models were investigated to represent the specific growth rate without inhibition, with inhibition by substrate and with inhibition by product, respectively. Model validation was performed using a new set of experimental data obtained at 34 °C and using 100 g L -1 of initial substrate concentration. The model proposed by Ghose and Tyagi was able to accurately describe the dynamics of ethanol production by S. cerevisiae CCA008 growing on cashew apple juice, containing an initial reducing sugar concentration ranging from 70 to 170 g L -1 and temperature, from 26 to 42 °C. The model optimization was also accomplished based on the following parameters: percentage volume of ethanol per volume of solution (%V ethanol /V solution ), efficiency and reaction productivity. The optimal operational conditions were determined using response surface graphs constructed with simulated data, reaching an efficiency and a productivity of 93.5% and 5.45 g L -1  h -1 , respectively.

Short-term tests with a pilot sewage plant and biofilm reactors for the biological degradation of the pharmaceutical compounds clofibric acid, ibuprofen, and diclofenac.

PubMed

Zwiener, C; Frimmel, F H

2003-06-20

The biodegradation of three active compounds of pharmaceuticals clofibric acid, ibuprofen, and diclofenac was investigated in short-term tests with a pilot sewage plant (PSP) and biofilm reactors (BFR, oxic and anoxic) as model systems for municipal sewage treatment. The PSP was characterized with respect to mixing behavior, the BFR with respect to biofilm content and sorption of the pharmaceutical compounds. The short-term experiments were carried out for 55 h in the PSP and for 48 h in the BFR. The concentration of the pharmaceuticals was in the microgram per liter range in presence of readily biodegradable substances in the milligram per liter range. Therefore, a too short time period and too low concentration to promote adaption of the microorganisms were applied. Under the operating conditions applied the biodegradation of the lipid lowering agent clofibric acid and the analgesic agents ibuprofen and diclofenac in the oxic BFR resembled that in the PSP. Clofibric acid and diclofenac were not eliminated and reached a level of approximately 95% of their initial concentration, whereas the concentration of ibuprofen was decreased to approximately 40% in the PSP and to approximately 35% in the oxic BFR. Both systems showed, therefore, an inherent ability for ibuprofen biodegradation. Elimination in the anoxic BFR resulted in a decrease of the concentration of all three substances to values between 60 and 80% of their initial concentration. In contrast to the PSP acetone revealed as inhibitor in the BFR. In both systems acetone was not degraded in the short-term tests.

Unitary Responses in Frog Olfactory Epithelium to Sterically Related Molecules at Low Concentrations

PubMed Central

Getchell, Thomas V.

1974-01-01

Responses of receptor cells in the frog's olfactory epithelium were recorded using platinum-black metal-filled microelectrodes. Spontaneous activity varied over a wide range from 0.07 to 1.8 spikes/s. Mean interspike intervals ranged from 13.7 to 0.5 s. Excitatory responses to six sterically related compounds at low concentrations were investigated. Stimuli were delivered in an aqueous medium. Thresholds for impulse initiation varied from greater than 1 mM down to the nanomolar concentration range. Thresholds of different olfactory receptors to the same stimulus could vary by several log units. Thresholds of the same receptor cell to different stimuli could be within the same order of magnitude, or could vary by as much as 5 log units. Based upon quantitative measures of stimulus-evoked excitatory responses it appeared that some receptors did not discriminate among sterically related molecules, whereas other receptors clearly discriminated between stimuli which evoke similar odor sensations. PMID:4211101

Adsorption of Cu(II) Ions in Aqueous Solutions by HCl Activated Carbon of Oil Palm

NASA Astrophysics Data System (ADS)

Muslim, A.; Syamsuddin, Y.; Salamun, A.; Abubakar; Ramadhan, D.; Peiono, D.

2017-06-01

Activated carbon was prepared from oil palm empty fruit bunch (OPEFB) by pyrolysis at 873.15 K in a furnace and chemical activation using 0.01 M HCl. Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and BET (Brunauer, Emmett and Teller) surface area analyses were taken into account to investigate the chemical functional group, to characterise the surface morphology and to determine total surface area the OPEFB AC, respectively. Experiments in batch mode were conducted to investigate Cu(II) adsorption capacity by the OPEFB AC whereas the system consisted of 1 g the OPEFB AC in 100 mL Cu(II) aqueous solution with initial concentration in the range of 10-70 mg/L, magnetic stirring at 75 rpm, room temperature of 300.15 K (± 2 K), at 1 atm and neutral pH over contact time in the range of 0-150 min. As the result, Cu(II) adsorption capacity increased exponentially over contact time and initial concentration. The Cu(II) adsorption kinetics followed the pseudo second order kinetics with the correlation coefficients (R 2), kinetics rate constant and equilibrium adsorption capacity being 0.98, 4.81 mg/g and 0.15/min, respectively for initial Cu(II) concentration being 58.71 mg/L. In addition, Cu(II) adsorption isotherm followed the Langmuir equation with the R2 value, the mono-layer and over-all adsorption capacity being 0.99, 5.92 mg/g and 0.17 L/mg, respectively.

Optimization of photocatalytic degradation of methyl blue using silver ion doped titanium dioxide by combination of experimental design and response surface approach.

PubMed

Sahoo, C; Gupta, A K

2012-05-15

Photocatalytic degradation of methyl blue (MYB) was studied using Ag(+) doped TiO(2) under UV irradiation in a batch reactor. Catalytic dose, initial concentration of dye and pH of the reaction mixture were found to influence the degradation process most. The degradation was found to be effective in the range catalytic dose (0.5-1.5g/L), initial dye concentration (25-100ppm) and pH of reaction mixture (5-9). Using the three factors three levels Box-Behnken design of experiment technique 15 sets of experiments were designed considering the effective ranges of the influential parameters. The results of the experiments were fitted to two quadratic polynomial models developed using response surface methodology (RSM), representing functional relationship between the decolorization and mineralization of MYB and the experimental parameters. Design Expert software version 8.0.6.1 was used to optimize the effects of the experimental parameters on the responses. The optimum values of the parameters were dose of Ag(+) doped TiO(2) 0.99g/L, initial concentration of MYB 57.68ppm and pH of reaction mixture 7.76. Under the optimal condition the predicted decolorization and mineralization rate of MYB were 95.97% and 80.33%, respectively. Regression analysis with R(2) values >0.99 showed goodness of fit of the experimental results with predicted values. Copyright © 2012 Elsevier B.V. All rights reserved.

Adsorption of arsenic from aqueous solution using magnetic graphene oxide

NASA Astrophysics Data System (ADS)

Sherlala, A. I. A.; Raman, A. A.; Bello, M. M.

2017-06-01

A binary of graphene oxide (GO) and iron oxide (IO) was prepared and used for the removal of arsenic from aqueous solution. The synthesized compound was characterized using XRD analysis. The prepared composite was used for the adsorption of arsenic from aqueous solution. Central Composite Design was used to design the adsorption experiments and to investigate the effects of operational parameters (initial concentration of arsenic, adsorbent dosage, pH and time) on the adsorption capacity and efficiency. The adsorbent shows a high adsorption capacity for the arsenic. The adsorption efficiency ranges between 33.2 % and 99.95 %. The most significant factors affecting the adsorption capacity were found to be the initial concentration of arsenic and the adsorbent dosage. The initial pH of the solution slightly affects the adsorption capacity, with the maximum adsorption capacity occurring around pH 6 - 7. Thus, the developed adsorbent has a potential for effective removal of arsenic from aqueous solution.

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

Cozzi, A; Cora Berry, C; Michael Bronikowski, M

The decontaminated salt solution waste stream from the Modular Caustic Side Solvent Extraction Unit and the Salt Waste Processing Facility is anticipated to contain entrained extraction solvent. The decontaminated salt solution is scheduled to be processed through Tank 50 into the Saltstone Production Facility. This study, among others, has been undertaken because the solvent concentration in the decontaminated salt solution may cause flammability issues within the Saltstone Disposal Facility that may need to be addressed prior to operation. Previous work at the Savannah River National Laboratory determined the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS withmore » Isopar{reg_sign} L concentrations ranging from 50 to 200 {micro}g/g in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the Isopar{reg_sign} L release data can be treated as a percentage of initial concentration in the concentration range studied. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release is larger than at lower temperatures. In this study, saltstone was prepared using a simulated decontaminated salt solution containing Isopar{reg_sign} L concentrations of 50 {micro}L/L (30 {micro}g/g) and 100 {micro}L/L (61 {micro}g/g) and cured at 55 C. The headspace of each sample was purged and the Isopar{reg_sign} L was trapped on a coconut shell carbon tube. The amount of Isopar{reg_sign} L captured was determined using NIOSH Method 1501. The percentage of Isopar{reg_sign} L released after 20 days was 1.4 - 3.7% for saltstone containing 50 {micro}L/L concentration and 2.1 - 4.3% for saltstone containing 100 {micro}L/L concentration. Given the measurement uncertainties in this work there is no clearly discernible relationship between percentage release and initial Isopar{reg_sign} L concentration.« less

Quantifying time-varying cellular secretions with local linear models.

PubMed

Byers, Jeff M; Christodoulides, Joseph A; Delehanty, James B; Raghu, Deepa; Raphael, Marc P

2017-07-01

Extracellular protein concentrations and gradients initiate a wide range of cellular responses, such as cell motility, growth, proliferation and death. Understanding inter-cellular communication requires spatio-temporal knowledge of these secreted factors and their causal relationship with cell phenotype. Techniques which can detect cellular secretions in real time are becoming more common but generalizable data analysis methodologies which can quantify concentration from these measurements are still lacking. Here we introduce a probabilistic approach in which local-linear models and the law of mass action are applied to obtain time-varying secreted concentrations from affinity-based biosensor data. We first highlight the general features of this approach using simulated data which contains both static and time-varying concentration profiles. Next we apply the technique to determine concentration of secreted antibodies from 9E10 hybridoma cells as detected using nanoplasmonic biosensors. A broad range of time-dependent concentrations was observed: from steady-state secretions of 230 pM near the cell surface to large transients which reached as high as 56 nM over several minutes and then dissipated.

Parameter optimization of electrolytic process of obtaining sodium hypochlorite for disinfection of water

NASA Astrophysics Data System (ADS)

Bogoslovskii, S. Yu; Kuznetsov, N. N.; Boldyrev, V. S.

2017-11-01

Electrochlorination parameters were optimized in flowing and non-flowing modes for a cell with a volume of 1 l. At a current density of 0.1 A/cm2 in the range of flow rates from 0.8 to 6.0 l/h with a temperature of the initial solution below 20°C the outlet temperature is maintained close to the optimal 40°C. The pH of the solution during electrolysis increases to 8.8 ÷ 9.4. There was studied a process in which a solution with a temperature of 7-8°C and a concentration of sodium chloride of 25 and 35 g/l in non-flowing cell was used. The dependence of the concentration of active chlorine on the electrolysis time varies with the concentration of the initial solution of sodium chloride. In case of chloride concentration of 25 g/l virtually linear relationship makes it easy to choose the time of electrolysis with the aim of obtaining the needed concentration of the product.

Survivability of Salmonella cells in popcorn after microwave oven and conventional cooking.

PubMed

Anaya, I; Aguirrezabal, A; Ventura, M; Comellas, L; Agut, M

2008-01-01

The survivability of Salmonella cells in popcorn preparation was determined for two distinct cooking methods. The first method used a standard microwave oven. The second method used conventional cooking in a pan. Prior to thermal processing in independent experiments, 12 suspensions in a range between 1x10(3) and 8x10(6) colony-forming units (CFU) per gram of Salmonella cells were inoculated in both raw microwave popcorn and conventional corn kernels. The influence of the initial concentration of Salmonella cells in the raw products and the lethal effects on Salmonella by thermal treatments for cooking were studied. Survival of Salmonella cells was determined in the thermally processed material by pre-enrichment and enrichment in selective medium, in accordance with the legislation for expanded cereals and cereals in flakes. Viable experimental contaminants were recovered from the conventionally cooked popcorn with initial inoculation concentrations of 9x10(4)cells/g or greater. Salmonella cell viability was significantly reduced after microwave oven treatment, with recoveries only from initial concentrations of 2x10(6)cells/g or superior.

Denitrification using a monopolar electrocoagulation/flotation (ECF) process.

PubMed

Emamjomeh, Mohammad M; Sivakumar, Muttucumaru

2009-01-01

Nitrate levels are limited due to health concerns in potable water. Nitrate is a common contaminant in water supplies, and especially prevalent in surface water supplies and shallow wells. Nitrate is a stable and highly soluble ion with low potential for precipitation or adsorption. These properties make it difficult to remove using conventional water treatment methods. A laboratory batch electrocoagulation/flotation (ECF) reactor was designed to investigate the effects of different parameters such as electrolysis time, electrolyte pH, initial nitrate concentration, and current rate on the nitrate removal efficiency. The optimum nitrate removal was observed at a pH range of between 9 and 11. It appeared that the nitrate removal rate was 93% when the initial nitrate concentration and electrolysis time respectively were 100 mg L(-1)-NO(3)(-) and 40 min. The results showed a linear relationship between the electrolysis time for total nitrate removal and the initial nitrate concentration. It is concluded that the electrocoagulation technology for denitrification can be an effective preliminary process when the ammonia byproduct must be effectively removed by the treatment facilities.

Value of point-of-care ketones in assessing dehydration and acidosis in children with gastroenteritis.

PubMed

Levy, Jason A; Waltzman, Mark; Monuteaux, Michael C; Bachur, Richard G

2013-11-01

Children with gastroenteritis often develop dehydration with metabolic acidosis. Serum ketones are frequently elevated in this population. The goal was to determine the relationship between initial serum ketone concentration and both the degree of dehydration and the magnitude of acidosis. This was a secondary analysis of a prospective trial of crystalloid administration for rapid rehydration. Children 6 months to 6 years of age with gastroenteritis and dehydration were enrolled. A point-of-care serum ketone (beta-hydroxybutyrate) concentration was obtained at the time of study enrollment. The relationship between initial serum ketone concentration and a prospectively assigned and previously validated clinical dehydration score, and serum bicarbonate concentration, was analyzed. A total of 188 patients were enrolled. The median serum ketone concentration was elevated at 3.1 mmol/L (interquartile range [IQR] = 1.2 to 4.6 mmol/L), and the median dehydration score was consistent with moderate dehydration. A significant positive relationship was found between serum ketone concentration and the clinical dehydration score (Spearman's rho = 0.22, p = 0.003). Patients with moderate dehydration had a higher median serum ketone concentration than those with mild dehydration (3.6 mmol/L vs. 1.4 mmol/L, p = 0.007). Additionally, the serum ketone concentration was inversely correlated with serum bicarbonate concentration (ρ = -0.26, p < 0.001). Children with gastroenteritis and dehydration have elevated serum ketone concentrations that correlate with both degree of dehydration and magnitude of metabolic acidosis. Point-of-care serum ketone measurement may be a useful tool to inform management decisions at the point of triage or in the initial evaluation of children with gastroenteritis and dehydration. © 2013 by the Society for Academic Emergency Medicine.

Dissolution of Uranium Oxides Under Alkaline Oxidizing Conditions

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

Smith, Steven C.; Peper, Shane M.; Douglas, Matthew

2009-11-01

Bench scale experiments were conducted to determine the dissolution characteristics of uranium oxide powders (UO2, U3O8, and UO3) in aqueous peroxide-carbonate solutions. Experimental parameters included H2O2 concentration, carbonate counter cation (NH4+, Na+, K+, and Rb+), and pH. Results indicate the dissolution rate of UO2 in 1 M (NH4)2CO3 increases linearly with peroxide concentration ranging from 0.05 – 2 M. The three uranium oxide powders exhibited different dissolution patterns however, UO3 exhibited prompt complete dissolution. Carbonate counter cation affected the dissolution kinetics. There is minimal impact of solution pH, over the range 8.8 to 10.6, on initial dissolution rate.

Changes in Postfermentation Quality during the Distribution Process of Anchovy ( Engraulis japonicus) Fish Sauce.

PubMed

Joung, Byung Chun; Min, Jin Gi

2018-06-01

In the present study, we evaluated the changes in quality that can occur during the distribution of nonheated anchovy ( Engraulis japonicus) fish sauce after packaging. The pH values of all samples ranged from 5.5 to 5.8, and there were no significant differences ( P > 0.05) in pH among the samples during storage regardless of storage temperature or salt concentration. The initial total volatile base nitrogen concentration in all samples after bottling was 115 to 121 mg/100 mL, but this concentration increased gradually with storage time. After 1 year of storage, total volatile base nitrogen concentration had increased to approximately 170% of the initial concentration (166 to 194 mg/100 mL). Amino nitrogen increased slightly during storage but was significantly lower than the increase in amino nitrogen during general anchovy fish sauce fermentation with anchovy flesh. Most of the free amino acids increased slightly during the storage period regardless of storage temperature or salt concentration, but tyrosine and histidine increased and then decreased during the storage period. The histamine concentration of the anchovy fish sauce at a salt concentration of 20% was 43.3 mg/100 mL initially, but after 1 year the histamine concentration was 89.7 mg/100 mL in samples stored at 10°C, 102.6 mg/100 mL in samples stored at 25°C, and 116.8 mg/100 mL in samples stored at 35°C . Changes in putrescine and cadaverine concentrations were similar to those in histamine; concentrations increased about twofold from the initial concentrations after 1 year of storage. However, the rate of increase in putrescine from 4 months after storage was very high, and cadaverine slightly decreased by 12 months of storage. High scores for umami and aroma sensory characteristics were given to samples stored at 10°C, but samples stored 35°C were given high scores for rancid. Despite the overall low scores for aroma and umami for samples stored at 35°C, the quality of the anchovy fish sauce as a fermented food was considered acceptable.

Groundwater-quality data in 12 GAMA study units: Results from the 2006–10 initial sampling period and the 2008–13 trend sampling period, California GAMA Priority Basin Project

USGS Publications Warehouse

Mathany, Timothy M.

2017-03-09

The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey in cooperation with the California State Water Resources Control Board. From 2004 through 2012, the GAMA-PBP collected samples and assessed the quality of groundwater resources that supply public drinking water in 35 study units across the State. Selected sites in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. Twelve of the study units, initially sampled during 2006–11 (initial sampling period) and sampled a second time during 2008–13 (trend sampling period) to assess temporal trends, are the subject of this report.The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 12 study units. In these study units, 550 sampling sites were selected by using a spatially distributed, randomized, grid-based method to provide spatially unbiased representation of the areas assessed (grid sites, also called “status sites”). After the initial sampling period, 76 of the previously sampled status sites (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend sites”). The 12 study units sampled both during the initial sampling and during the trend sampling period were distributed among 6 hydrogeologic provinces: Coastal (Northern and Southern), Transverse Ranges and Selected Peninsular Ranges, Klamath, Modoc Plateau and Cascades, and Sierra Nevada Hydrogeologic Provinces. For the purposes of this trend report, the six hydrogeologic provinces were grouped into two hydrogeologic regions based on location: Coastal and Mountain.The groundwater samples were analyzed for a number of synthetic organic constituents (volatile organic compounds, pesticides, and pesticide degradates), constituents of special interest (perchlorate and 1,2,3-trichloropropane), and natural inorganic constituents (nutrients, major and minor ions, and trace elements). Isotopic tracers (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water) also were measured to help identify processes affecting groundwater quality and the sources and ages of the sampled groundwater. More than 200 constituents and water-quality indicators were measured during the trend sampling period.Quality-control samples (blanks, replicates, matrix-spikes, and surrogate compounds) were collected at about one-third of the trend sites, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. On the basis of detections in laboratory and field blank samples collected by GAMA-PBP study units, including the 12 study units presented here, reporting levels for some groundwater results were adjusted in this report. Differences between replicate samples were mostly within acceptable ranges, indicating low variability in analytical results. Matrix-spike recoveries were largely within the acceptable range (70 to 130 percent).This study did not attempt to evaluate the quality of water delivered to consumers. After withdrawal, groundwater used for drinking water typically is treated, disinfected, and blended with other waters to achieve acceptable water quality. The comparison benchmarks used in this report apply to treated water that is served to the consumer, not to untreated groundwater. To provide some context for the results, however, concentrations of constituents measured in these groundwater samples were compared with benchmarks established by the U.S. Environmental Protection Agency and the State of California. Comparisons between data collected for this study and benchmarks for drinking water are for illustrative purposes only and are not indicative of compliance or non-compliance with those benchmarks.Most organic constituents that were detected in groundwater samples from the trend sites were found at concentrations less than health-based benchmarks. One volatile organic compound—perchloroethene—was detected at a concentration greater than the health-based benchmark in samples from one trend site during the initial and trend sampling periods. Chloroform was detected in at least 10 percent of the samples at trend sites in both sampling periods. Methyl tert-butyl ether was detected in samples from more than 10 percent of the trend sites during the initial sampling period. No pesticide or pesticide degradate was detected in greater than 10 percent of the samples from trend sites or at concentrations greater than their health-based benchmarks during either sampling period. Nutrients were not detected at concentrations greater than their health-based benchmarks during either sampling period.Most detections of major ions and trace elements in samples from trend sites were less than health-based benchmarks during both sampling periods. Arsenic and boron each were detected at concentrations greater than the health-based benchmark in samples from four trend sites during the initial and trend sampling periods. Molybdenum was detected in samples from four trend sites at concentrations greater than the health-based benchmark during both sampling periods. Samples from two of these trend sites had similar molybdenum concentrations, and two had substantially different concentrations during the initial and trend sampling periods. Uranium was detected at a concentration greater than the health-based benchmark only at two trend sites.

An Eulerian model for scavenging of pollutants by raindrops

NASA Astrophysics Data System (ADS)

Kumar, Sudarshan

An Eulerian model for simulating the coupled processes of gas-phase depletion and aqueousphase accumulation of the pollutant species during a rain event has been formulated. The model is capable of taking into account any realistic vertical profile of pollutant species concentrations and time-dependent initial aqueous-phase concentrations at the cloud base. The model considers the processes of single species absorption and dissociation in the aqueous phase. The coupled partial differential equations constituting the model are discretized into a set of ordinary differential equations by using the Galerkin method with chapeau functions as the basis functions. These equations are solved to obtain the pollutant concentrations of the gas phase and raindrops as well as the pH of raindrops as a function of time and distance below cloud-base. Simulations are performed for scavenging of gaseous HNO 3, H 2O 2, SO 2, formaldehyde and NH 3. For the case of highly soluble HNO 3 and H 2O 2, raindrops are far from equilibrium with the gas phase and their capacity for absorption of these gases is undiminished even as they reach ground level. The gas-phase concentrations for these species decrease exponentially with time and the washout is determined primarily by the rain intensity and mass-transfer coefficient of the gaseous species to the raindrops. The pollutant species concentrations in raindrops are an almost linear function of the distance below the cloud base. For the simulation conditions considered in this study, the half-life periods of these gases for removal from the atmosphere range from 15 to 40 min. For SO 2 and formaldehyde, the aqueous-phase concentrations approach equilibrium as the drops fall to ground level and the gas-phase concentrations show large gradients in the vertical. Half-life periods for SO 2 range from 1.3 to 13 h depending on the initial raindrop pH and rain intensity. For formaldehyde, the half-life ranges from 19 to 63 min. Solubility of NH 3 is a strong function of the raindrop pH. As NH 3 is absorbed, the raindrop pH increases and NH 3 solubility decreases. For pre-acidified drops (pH = 4.6), ammonia solubility is very high and the drops are far from equilibrium with the gas phase throughout the falling period. The half-life for ammonia ranges from 11 min to over 3 h in our simulations.

Kinetics of atrazine, deisopropylatrazine, and deethylatrazine soil biodecomposers.

PubMed

la Cecilia, Daniele; Maggi, Federico

2016-12-01

Twenty-two experimental sets were used to determine the biodecomposition parameters of atrazine (ATZ), deisopropylatrazine (DIATZ), and deethylatrazine (DEATZ) by inverse solution of Michaelis-Menten-Monod kinetic equations. The averaged maximum specific growth rate (μ), Michaelis-Menten half-saturation concentration (K), and biomass yield (Y) ranged between 2.00 × 10 -7 and 4.62 × 10 -5  1/s, 3.43 × 10 -6 and 1.39 × 10 1  mol/L, and 1.20 × 10 2 and 2.98 × 10 5  mg-wet-Bio/mol-Subs, respectively. Parameters grouped by reaction pathway appeared clustered by aerobic and anaerobic catabolic breakdown, and were poorly correlated between each other (R ranging from -0.27 to 0.63, p ≥ 0.05). The tested bacterial strains decomposed ATZ, DIATZ, and DEATZ relatively rapidly in laboratory conditions, with an half-life (t 1/2 ) ranging between 3 and 6 days. Numerical modeling showed that ATZ, DIATZ, and DEATZ half-lives were particularly sensitive to their initial concentration and the initial microbial biomass concentration. This study suggests that these bacterial strains can effectively be used or enhanced for bioremediation of agricultural soils where atrazine has been applied as long as these bacteria already coexist in or can integrate with the local soil microbial population at a given location. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phytoremediation for the Containment and Treatment of Energetic and Propellant Material Releases on Testing and Training Ranges

DTIC Science & Technology

2011-06-01

20  Figure 5. Removal of TNT from hydroponic solution by Panicum vigratum Alamo after spiking solution to give an initial...Removal of TNT from hydroponic solution by Paspalum notatum (bahiagrass) Pensacola after spiking solution to give an initial concentration of 2, 5, 10, 25...in 0.5x Hoagland hydroponic solution and were placed in a controlled environmental growth chamber at 50% RH, 28°C with a 16:8h light:dark photoperiod

Mineralocorticoid before glucocorticoid deficiency in a dog with primary hypoadrenocorticism and hypothyroidism.

PubMed

McGonigle, Kathryn M; Randolph, John F; Center, Sharon A; Goldstein, Richard E

2013-01-01

A dog with an unexpected presentation of primary hypoadrenocorticism was evaluated for clinical signs and electrolyte abnormalities characteristic of Addison's disease. Although the initial adrenocorticotropic hormone (ACTH) stimulation test documented serum cortisol concentrations within the reference range, subsequent assessments confirmed hypoaldosteronism. Mineralocorticoid replacement promptly normalized electrolytes and transiently improved clinical illness. Six weeks after initial ACTH stimulation testing, the dog became glucocorticoid deficient. Concurrent primary hypothyroidism was also documented. Hypoaldosteronism preceding hypocortisolemia is a unique presentation of canine Addison's disease.

Marine sediment sample preparation for analysis for low concentrations of fine detrital gold

USGS Publications Warehouse

Clifton, H. Edward; Hubert, Arthur; Phillips, R. Lawrence

1967-01-01

Analyses by atomic absorption for detrital gold in more than 2,000 beach, offshore, marine-terrace, and alluvial sands from southern Oregon have shown that the values determined from raw or unconcentrated sediment containing small amounts of gold are neither reproducible nor representative of the initial sample. This difficulty results from a 'particle sparsity effect', whereby the analysis for gold in a given sample depends more upon the occurrence of random flakes of gold in the analyzed portion than upon the actual gold content of the sample. The particle sparsity effect can largely be eliminated by preparing a gold concentrate prior to analysis. A combination of sieve, gravimetric, and magnetic separation produces a satisfactory concentrate that yields accurate and reproducible analyses. In concentrates of nearly every marine and beach sand studied, the gold occurs in the nonmagnetic fraction smaller than 0.124 mm and with a specific gravity greater than 3.3. The grain size of gold in stream sediments is somewhat more variable. Analysis of concentrates provides a means of greatly increasing the sensitivity of the analytical technique in relation to the initial sample. Gold rarely exceeds 1 part per million in even the richest black sand analyzed; to establish the distribution of gold (and platinum) in marine sediments and its relationship to source and environmental factors, one commonly needs to know their content to the part per billion range. Analysis of a concentrate and recalculation to the value in the initial sample permits this degree of sensitivity.

Pharmacokinetics and clinical application of intravenous valproate in Thai epileptic children.

PubMed

Visudtibhan, Anannit; Bhudhisawadi, Kasama; Vaewpanich, Jarin; Chulavatnatol, Suvatna; Kaojareon, Sming

2011-03-01

Roles of intravenous administration of valproate in status epilepticus and serial seizures are documented in adults and children. Pharmacokinetic parameters are necessary to predict the optimum therapeutic level after administration. A cross-sectional study to determine the pharmacokinetic parameters and safety of intravenous valproate for future application was conducted in Thai children from January to December 2008. There were eleven children, age-range 1-15 years (mean age 9.5 years) enrolled. Valproate of 15-20 mg/kg was administrated intravenously at the rate of 3 mg/kg/min, followed by 6 mg/kg every 6 h. Valproate level was determined prior to the initial dose and at ½, 1, 2, 4, 5, and 6 h postdose. Complete blood count, serum ammonia, and liver function tests were collected prior to the initial dose and at 6 h. Median loading dose was 19 mg/kg (range 15-20.5 mg/kg). Median maximum concentration at 30 min after infusion was 98.8 mcg/mL (range 67-161 mcg/mL). Median volume of distribution was 0.20 L/kg (range 0.15-0.53 L/kg). Median half-life was 9.5 h (range 4.4-24.2 h). Median clearance was 0.02 L/h/kg (range 0.01-0.05 L/h/kg). Six hours after initial dose, eight children did not have recurrent seizure. One child had brief seizure at 20 min after initial dose. Seizure recurred in two children at 4th and 5th hour. Asymptomatic transient elevation of serum ammonia was observed in two children. Volume of distribution of 0.20 L/kg could be applied for initial intravenous administration with a favorable efficacy. Copyright © 2010 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Evaluation of Nickel and Chromium Ion Release During Fixed Orthodontic Treatment Using Inductively Coupled Plasma-Mass Spectrometer: An In Vivo Study

PubMed Central

Nayak, Rabindra S; Khanna, Bharti; Pasha, Azam; Vinay, K; Narayan, Anjali; Chaitra, K

2015-01-01

Background: Fixed orthodontic appliances with the use of stainless steel brackets and archwires made of nitinol have a corrosive potential in the oral environment. Nickel and chromium ions released from these appliances act as allergens apart from being cytotoxic, mutagenic and carcinogenic in smaller quantities in the range of nanograms. This study was done to evaluate the release of nickel and chromium ions from orthodontic appliances in the oral cavity using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Materials and Methods: Saliva samples from 30 orthodontic patients undergoing treatment with 0.022″ MBT mechanotherapy were collected prior to commencement of treatment, after initial aligning wires and after 10-12 months of treatment. Salivary nickel and chromium ion concentration was measured in parts per billion (ppb) using ICP-MS. Results: Mean, standard deviation and range were computed for the concentrations of ions obtained. Results analyzed using ANOVA indicated a statistically significant increase of 10.35 ppb in nickel ion concentration and 33.53 ppb in chromium ion concentration after initial alignment. The ionic concentration at the end of 10-12 months of treatment showed a statistically significant increase in of 17.92 ppb for chromium and a statistically insignificant decrease in nickel ion concentration by 1.58 ppb. Pearson’s correlation coefficient showed a positive correlation for an increase in nickel concentration after aligning, but not at the end of 10-12 months. A positive correlation was seen for an increase in chromium ion concentration at both time intervals. Conclusion: Nickel and chromium ion concentration in saliva even though below the recommended daily allowance should not be ignored in light of the new knowledge regarding effects of these ions at the molecular level and the allergic potential. Careful and detailed medical history of allergy is essential. Nickel free alternatives should form an essential part of an orthodontist’s inventory. PMID:26464533

Evaluation of Nickel and Chromium Ion Release During Fixed Orthodontic Treatment Using Inductively Coupled Plasma-Mass Spectrometer: An In Vivo Study.

PubMed

Nayak, Rabindra S; Khanna, Bharti; Pasha, Azam; Vinay, K; Narayan, Anjali; Chaitra, K

2015-08-01

Fixed orthodontic appliances with the use of stainless steel brackets and archwires made of nitinol have a corrosive potential in the oral environment. Nickel and chromium ions released from these appliances act as allergens apart from being cytotoxic, mutagenic and carcinogenic in smaller quantities in the range of nanograms. This study was done to evaluate the release of nickel and chromium ions from orthodontic appliances in the oral cavity using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Saliva samples from 30 orthodontic patients undergoing treatment with 0.022″ MBT mechanotherapy were collected prior to commencement of treatment, after initial aligning wires and after 10-12 months of treatment. Salivary nickel and chromium ion concentration was measured in parts per billion (ppb) using ICP-MS. Mean, standard deviation and range were computed for the concentrations of ions obtained. Results analyzed using ANOVA indicated a statistically significant increase of 10.35 ppb in nickel ion concentration and 33.53 ppb in chromium ion concentration after initial alignment. The ionic concentration at the end of 10-12 months of treatment showed a statistically significant increase in of 17.92 ppb for chromium and a statistically insignificant decrease in nickel ion concentration by 1.58 ppb. Pearson's correlation coefficient showed a positive correlation for an increase in nickel concentration after aligning, but not at the end of 10-12 months. A positive correlation was seen for an increase in chromium ion concentration at both time intervals. Nickel and chromium ion concentration in saliva even though below the recommended daily allowance should not be ignored in light of the new knowledge regarding effects of these ions at the molecular level and the allergic potential. Careful and detailed medical history of allergy is essential. Nickel free alternatives should form an essential part of an orthodontist's inventory.

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

Ford, JP; Thapaliya, N; Kelly, MJ

Fatty acids (FAs) derived via thermal hydrolysis of food-grade lard and canola oil were deoxygenated in the liquid phase using a commercially available 5 wt % Pd/C catalyst. Online quadrupole mass spectrometry and gas chromatography were used to monitor the effluent gases from the semi-batch stirred autoclave reactors. Stearic, oleic, and palmitic acids were employed as model compounds. A catalyst lifetime exceeding 2200 turnovers for oleic acid deoxygenation was demonstrated at 300 degrees C and 15 atm under 10% H-2. The initial decarboxylation rate of palmitic acid under 5% H-2 decreases sharply with increasing initial concentration; in contrast, the initialmore » decarbonylation rate increases linearly, indicative of first-order kinetics. Scale-up of diesel-range hydrocarbon production was investigated by increasing the reactor vessel size, initial FA concentration, and FA/catalyst mass ratio. Lower CO2 selectivity and batch productivity were observed at the larger scales (600 and 5000 mL), primarily because of the higher initial FA concentration (67 wt %) employed. Because unsaturated FAs must be hydrogenated before deoxygenation can proceed at an appreciable rate, the additional batch time required for FA hydrogenation reduces the batch productivity for unsaturated feedstocks. Low-temperature hydrogenation of unsaturated feedstocks (using Pd/C or another less-expensive catalyst) prior to deoxygenation is recommended.« less

The utilization of a non-invasive fluorescence imaging system to follow clinical dermatological MAL-PDT

NASA Astrophysics Data System (ADS)

Tyrrell, Jessica; Campbell, Sandra; Curnow, Alison

2009-06-01

This study employed a commercially available, non-invasive, fluorescence imaging system (Dyaderm, Biocam, Germany), to measure protoporphyrin IX (PpIX) concentration at several different stages during clinical dermatological methyl aminolevulinate photodynamic therapy (MAL-PDT). We validated the system prior to use to ensure that the PpIX changes witnessed were accurate and not due to environmental or user induced artifacts. The system was then employed to acquire color (morphological) and fluorescent (physiological) images simultaneously during dermatological PDT. Clinical data was collected from a range of licensed dermatological conditions (actinic keratosis, Bowen's disease and superficial basal cell carcinoma) during initial and subsequent PDT treatment cycles. The initial clinical data indicated that each type of licensed lesion considered responded in a similar manner following the application of Metvix (Galderma, U.K.) and the subsequent light irradiation (Aktilite, Galderma, U.K.). Images acquired three hours after Metvix application showed a significant increase in PpIX concentration within the lesion (P < 0.05), whilst PpIX levels in the surrounding normal tissue remained unaltered. After irradiation, the PpIX concentration was significantly decreased and returned to a level similar to the initial concentration originally observed. Lesions that received subsequent treatment cycles accumulated significantly less PpIX (P < 0.05) prior to irradiation.

Integrated electrokinetics-adsorption remediation of saline-sodic soils: effects of voltage gradient and contaminant concentration on soil electrical conductivity.

PubMed

Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Lukman, Salihu; Bukhari, Alaadin

2013-01-01

In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD) was used for the experimental design and response surface methodology (RSM) was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whose R (2) ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors.

Levels, distribution and air-soil exchange fluxes of polychlorinated biphenyls (PCBs) in the environment of Punjab Province, Pakistan.

PubMed

Syed, Jabir Hussain; Malik, Riffat Naseem; Li, Jun; Zhang, Gan; Jones, Kevin C

2013-11-01

An initial survey of the concentrations of polychlorinated biphenyl (PCB) compounds in air and soils across industrial and agricultural areas of Punjab Province, Pakistan, was conducted from January to March 2011. The total concentration of all PCBs (31 PCBs) ranged from 34 to 389pgm(-3) in air and from 7 to 45ngg(-1) dry weight in soils, where both ranges were similar to the average ranges in other areas of the world. PCBs were elevated across industrial regions near urban and industrial sources. Consistently low air concentrations of PCBs at the agricultural sites suggest that they are less widespread or uniformly distributed in the Pakistani atmosphere. The calculated air and soil fugacity fraction values indicated that soils are a potential secondary source of PCBs in agricultural areas, whereas they are in equilibrium or atmospheric deposition in industrial and urban areas. TEQ concentrations of dioxin-like PCBs for soil samples met the Canadian standard. However, local authorities should address the human health threats from urban and industrial soils in Punjab Province, Pakistan. Copyright © 2013 Elsevier Inc. All rights reserved.

Passive Measurements of Thoron and its Progeny in some Dwellings in Ireland

NASA Astrophysics Data System (ADS)

Choncubhair, Órlaith Ní; Laughlin, James Mc; Tokonami, Shinji

2008-08-01

In this paper, an account is given of the development, calibration and field use of a passive alpha track detector sensitive to thoron as well as to radon. No database of thoron and thoron progeny concentrations in dwellings in Ireland exists and, as a result, the level of exposure of the Irish population to thoron and its progeny is unknown. As an initial or pilot stage in establishing such a data base measurements of thoron and thoron progeny concentrations (the latter expressed in Equilibrium Equivalent Thoron Concentration (EETC)) were made in 40 randomly chosen Irish dwellings. The EETC measurements were made using a passive thoron progeny deposition rate monitor designed and supplied by NIRS (Japan). In addition standard unmodified SSI passive radon detectors were used to measure radon in these dwellings. The measured thoron concentrations ranged from below the level of detection to 154 Bq/m3 while the radon gas ranged from 15 to 179 Bq/m3. The thoron progeny EETC values for these dwellings ranged from 0.03 to 7.7 Bq/m3. An account is also given of the dosimetric implications of these measurements.

Establishment of reference values for various coagulation tests in healthy Florida manatees (Trichechus manatus latirostris) and evaluation of coagulation in debilitated manatees during rehabilitation.

PubMed

Gerlach, Trevor J; Bandt, Carsten; Conner, Bobbi; Ball, Ray L

2015-11-01

To establish reference ranges for coagulation parameters in healthy Florida manatees (Trichechus manatus latirostris) and compare results with those for debilitated manatees undergoing treatment at a rehabilitation facility. Prospective study. 29 healthy manatees and 45 debilitated manatees with various diseases. Manatees considered healthy on the basis of results of physical examination, CBC, and serum biochemical analysis underwent coagulation testing including measurement of prothrombin time, partial thromboplastin time, D-dimer concentration, platelet count, and fibrinogen concentration to establish reference ranges. For comparison, a group of manatees undergoing rehabilitation was also tested, and the results were compared. Thromboelastography was also performed on some animals. Values for D-dimer concentration were significantly higher in debilitated versus healthy animals. There was no significant difference for prothrombin time, partial thromboplastin time, platelet count, or fibrinogen concentration between groups. Thromboelastography was performed on 8 healthy animals. Reference ranges were established for various tests of coagulation that may assist clinicians during the initial evaluation and rehabilitation of Florida manatees. Future research to evaluate the effect of specific disease processes on the coagulation cascade is recommended.

An investigation of the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in authentic urine samples.

PubMed

Skopp, Gisela; Pötsch, Lucia

2004-01-01

Preanalytical stability of a drug and its major metabolites is an important consideration in pharmacokinetic studies or whenever the analyte pattern is used to estimate drug habits. Firstly, the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH, THCCOOglu) in authentic urine samples was investigated. Random urine samples of cannabis users (n = 38) were stored at -20, 4, and 20 degrees C up to 15 days and up to 5 days at 40 degrees C, and alterations of the analyte pattern during storage were followed by liquid chromatography-tandem mass spectrometry. Secondly, the influence of pH (range 5.0-8.0) on the stability of the analytes was studied using spiked urine to elucidate the results obtained from authentic samples. In authentic urine samples, the initial pH ranged from 5.1 to 8.8. The glucuronide was found to be highly labile at a storage temperature of 4 degrees C and above. Initially, 18 urine samples tested positive for THCCOOH. After 2 days storage at 20 degrees C, THCCOOH was detectable in a further 4 samples, and 7 more samples tested positive for THCCOOH (5-81 ng/mL) after 15 days. Depending on time and temperature, the glucuronide concentration decreased, resulting in an increase of THCCOOH concentration. However, a loss in mean total THCCOOH concentration was found, which was significantly higher in deteriorated samples than in samples without signs of deterioration after 15 days of storage at 20 degrees C. In the drug-free urine sample separately spiked with THCCOOglu or THCCOOH, the investigations on the stability of the target analytes at various pH values revealed that THCCOOH was stable at pH 5.0. At higher pH values, its concentration slightly decreased with time, and about 69% of the initial THCCOOH concentration was still present at pH 8.0 on day 5. THCCOOglu concentrations rapidly decreased with increasing pH value. For example, only 72% of the initial THCCOOglu concentration could be detected at pH 5.0 on day 1. Degradation of the glucuronide resulted in formation of THCCOOH, which was observed even at pH 5.0. In light of the present findings, advanced forensic interpretations based on the presence of THCCOOH or the pattern of THCCOOH and THCCOOglu in stored urine samples seems questionable.

U.S. National PM2.5 Chemical Speciation Monitoring Networks – CSN and IMPROVE: Description of Networks

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) initiated the national PM2.5 Chemical Speciation Monitoring Network (CSN) in 2000 to support evaluation of long-term trends and to better quantify the impact of sources on particulate matter (PM) concentrations in the size range belo...

Uptake of Nickel by Synthetic Mackinawite

EPA Science Inventory

The uptake of aqueous Ni(II) by synthetic mackinawite (FeS) was examined in anaerobic batch experiments at near-neutral pH (5.2 to 8.4). Initial molar ratios of Ni(II) to FeS ranged from 0.008 to 0.83 and maximum Ni concentrations in mackinawite, expressed as the cation mol fract...

Malachite Green Adsorption by Spent Coffee Grounds

NASA Astrophysics Data System (ADS)

Syamimie Atirah Mat, Siti; Zati Hanani Syed Zuber, Sharifah; Rahim, Siti Kartini Enche Ab; Sohaimi, Khairunissa Syairah Ahmad; Halim, Noor Amirah Abdul; Fauziah Zainudin, Nor; Aida Yusoff, Nor; Munirah Rohaizad, Nor; Hidayah Ishak, Noor; Anuar, Adilah; Sarip, Mohd Sharizan Md

2018-03-01

In this work, the ability of spent coffee grounds (SCG) as a low-cost adsorbent to remove malachite green (MG) from aqueous solutions was studied. Batch adsorption tests were carried out to observe the effect of various experimental parameters such as contact time, initial concentration of malachite green and adsorbent dosage on the removal of dye. The results obtained show that the percentage of dye removal will decreased with the increased of initial concentration of dye in the range of 50 mg/L to 250 mg/L. Besides, percentage removal of dye was also found to be increased as the contact time increased until it reached equilibrium condition. The results also showed that the adsorbent dosage in range of 0.2 g to 1.0 g is proportional to the percentage removal of malachite green dye. Study on the kinetic adsorption and isotherm adsorption has also been investigated. The adsorption isotherm data were described by Langmuir isotherm with high-correlation coefficients while the experimental data showed the pseudo-second-order kinetics model was the best model for the adsorption of MG by SCG with the coefficients of correlation R2 > 0.9978.

The effects of inpatient hybrid closed-loop therapy initiated within 1 week of type 1 diabetes diagnosis.

PubMed

Buckingham, Bruce A; Beck, Roy W; Ruedy, Katrina J; Cheng, Peiyao; Kollman, Craig; Weinzimer, Stuart A; DiMeglio, Linda A; Bremer, Andrew A; Slover, Robert; Cantwell, Martin

2013-05-01

This article describes our experience with inpatient hybrid closed-loop control (HCLC) initiated shortly after the diagnosis of type 1 diabetes in a randomized trial designed to assess the effectiveness of inpatient HCLC followed by outpatient sensor-augmented pump (SAP) therapy on the preservation of β-cell function. Forty-eight individuals with newly diagnosed type 1 diabetes and positive pancreatic autoantibodies (7.8-37.7 years old) received inpatient HCLC therapy for up to 93 h, initiated within 7 days of diagnosis. On initiation of HCLC, mean glucose concentration was 240±100 mg/dL. During the first day of HCLC, median of the participant's mean glucose concentrations fell rapidly to 146 mg/dL, a level of control that was sustained on Days 2 and 3 (138 mg/dL and 139 mg/dL, respectively). By Day 3, the median percentage of glucose values >250 and <60 mg/dL was <1%. During the first 2 weeks of SAP treatment at home, the median participant mean glucose level was 126 mg/dL (interquartile range, 117, 137 mg/dL), and the median percentage of values between 71 and 180 mg/dL was 85% (interquartile range, 80%, 90%). Inpatient HCLC followed by outpatient SAP therapy can provide a safe and effective means to rapidly reverse glucose toxicity and establish near-normal glycemic control in patients with newly diagnosed type 1 diabetes.

The Effect of the Concentration of Oxidant, Cr(VI), on the Iron Oxidation in Saline Water

NASA Astrophysics Data System (ADS)

Ahn, H.; Jo, H. Y.; Ryu, J. H.; Koh, Y. K.

2014-12-01

Deep geological disposal is currently considered as the most appropriate method to isolate high level radioactive wastes (HLRWs) from the ecosystem. If groundwater seeps into underground disposal facilities, water molecules can be dissociated to radicals or peroxides, which can oxidize metal canisters and HLRWs. The oxidized radionuclides with a high solubility can be dissolved in the groundwater. Some dissolved radionuclides can act as oxidants. The continuous radiolysis of water molecules, which results from continuous seepage of groundwater, can enable the continuous production of the radioactive oxidants, resulting in an increase in concentration of oxidants. In this study, the effect of oxidant concentration on iron oxidation in the presence of salt was evaluated. Zero valent iron (ZVI) particles were reacted with Cr(VI) solutions with initial Cr(VI) concentrations ranged from 50 to 300 mg/L in reactors. The initial pH and NaCl concentration were fixed at 3 and 0.5 M, respectively. An increase in the initial Cr(VI) concentration caused an increase in the rate and extend of H2 gas production. The decrement of Cr(VI) was increased as the initial Cr(VI) concentration was increased. The penetration of H+ ions in the presence Cl- ions through the passive film on the ZVI particles caused the reaction between H+ ions and ZVI particles, producing H2 gas and Fe2+ ions. The passive film was damaged during the reaction due to the eruption of H2 gas or peptization by Cl- ions. The Fe2+ ions were reacted with Cr(VI) ions in the solution, producing Fe(III)-Cr(III) (oxy)hydroxides on the passive film of ZVI particles or in the solution as colloidal particles. The Fe(III)-Cr(III) (oxy)hydroxides tends to be precipitated as colloidal particles at a high Cr(VI) concentration and precipitated on the passive film at a low Cr(VI) concentration. The passive film was repaired or thickened by additional formation of Fe(III)-Cr(III) (oxy)hydroxides at a lower Cr(VI) concentration.

Initial effects of Stagecoach Reservoir on discharge, water-quality characteristics, and suspended-sediment loads in the Yampa River, northwestern Colorado

USGS Publications Warehouse

Tobin, R.L.

1996-01-01

The construction and filling of Stagecoach Reservoir on the Yampa River during 1988-91 were done to enhance water management and to use local water resources. To assess the initial effects of the reservoir on the hydrology of the upper Yampa River, physical, chemical, and biological data were collected at a site upstream (YR-1) during water years 1989-92 and a site downstream (YR-2) from the reservoir during water years 1985-92 and at two sites in the reservoir during 1990-92. Annual suspended-sediment loads were determined for the Yampa River for water years 1985-92, and sediment retention in Stagecoach Reservoir was estimated. The initial filling of the 33,275-acre-foot reservoir proceeded slower than expected because inflow from the Yampa River was about 50 to 73 percent of average during water years 1989-91. Secchi-disk measurements in Stagecoach Reservoir ranged from 2.5 to 18 feet. Algal growth and sediment transport during stormy weather decreased water clarity, and possible algal grazing by zooplankton and sediment deposition improved water clarity. Water temperature in the reservoir ranged from 0 to 22 degrees Celsius, and thermal stratification was maintained during summer. Values of pH ranged from 7.2 in the hypolimnion to 8.9 in the epilimnion. Changes in pH were related to photosynthesis and respiration. Concentrations of dissolved oxygen in the reservoir ranged from 0 milligram per liter in the hypolimnion to 13 milligrams per liter in the epilimnion. Average 5-day biochemical-oxygen-demand rates ranged from 0.33 to 0.46 milligram per liter per day. Oxygen production from photosynthesis was greatest in the epilimnion; oxygen depletion from respiration was characteristic in the hypolimnion. Near or above average inflow might decrease the incidence of anaerobic conditions. Specific conductance in the reservoir ranged from 414 to 520 microsiemens per centimeter at 25 degrees Celsius, depending on the specific conductance of inflow from the Yampa River. The water was a very hard, calcium bicarbonate type. Nitrogen input to the reservoir was mostly as organic nitrogen that ranged in concentration from less than 0.18 to about 1.0 milligram per liter. Concentrations of dissolved phosphorus in the inflow of the Yampa River ranged from less than 0.01 to 0.06 milligram per liter. Decomposition of organic material and release of nutrients from sediments under reducing conditions were probable causes for dissolved-ammonia concentrations near the reservoir bottom to increase to maximum values of 0.9 to 1.6 milligrams per liter as nitrogen during thermal stratification in summer. Dissolved phosphorus also increased in the same conditions to a range of 0.32 to 0.35 milligram per liter. Except for concentrations of total recoverable manganese that ranged from 210 to 440 micrograms per liter near the reservoir bottom, most concentrations of 20 trace constituents were measured at or near analytical detection limits. A total of 119 phytoplankton from 7 phyla was identified in Stagecoach Reservoir during 1990-92. Cyanophyta (blue-green algae) accounted for most of the cell counts. Cyanophyta blooms of Aphanizomenon and Aphanocapsa developed during 1990-92, and photosynthesis caused concentrations of dissolved oxygen to exceed 150-percent saturation in the epilimnion. Diversity index values for phytoplankton ranged from 0.05 to 3.06. Values of diversity index during the summer of 1992 indicated that the community diversity of algae could be greatest in spring and least in fall. All colony counts of fecal coliform bacteria in the reservoir during 1990-92 were less than criteria limits set by the State of Colorado. During water years 1985-88 (preconstruction period), at a site on the Yampa River downstream from the proposed damsite, and water years 1989-92 (post-construction period), at a site upstream from the dam, annual loads of suspended sediment ranged from 2,480 to 22,650 tons. The average annual suspended-sediment load for th

On the role of ice-nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems

NASA Astrophysics Data System (ADS)

Ladino, Luis A.; Korolev, Alexei; Heckman, Ivan; Wolde, Mengistu; Fridlind, Ann M.; Ackerman, Andrew S.

2017-02-01

Over the decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particle concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system.

On the role of ice-nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems

PubMed Central

Ladino, Luis A.; Korolev, Alexei; Heckman, Ivan; Wolde, Mengistu; Fridlind, Ann M.; Ackerman, Andrew S.

2018-01-01

Over decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particles concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in-situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system. PMID:29551842

Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

NASA Astrophysics Data System (ADS)

Dasbiswas, K.; Alster, E.; Safran, S. A.

2016-06-01

Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development.

Activation of pollen tube callose synthase by detergents. Evidence for different mechanisms of action.

PubMed Central

Li, H; Bacic, A; Read, S M

1997-01-01

In pollen tubes of Nicotiana alata, a membrane-bound, Ca(2+)-independent callose synthase (CalS) is responsible for the biosynthesis of the (1,3)-beta-glucan backbone of callose, the main cell wall component. Digitonin increases CalS activity 3- to 4-fold over a wide range of concentrations, increasing the maximum initial velocity without altering the Michaelis constant for UDP-glucose. The CalS activity that requires digitonin for assay (the latent CalS activity) is not inhibited by the membrane-impermeant, active site-directed reagent UDP-pyridoxal when the reaction is conducted in the absence of digitonin. This is consistent with digitonin increasing CalS activity by the permeabilization of membrane vesicles. A second group of detergents, including 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate (CHAPS), Zwittergent 3-16, and 1-alpha-lysolecithin, activate pollen tube CalS 10- to 15-fold, but only over a narrow range of concentrations just below their respective critical micellar concentrations. This activation could not be attributed to any particular chemical feature of these detergents. CHAPS increases maximum initial velocity and decreases the Michaelis constant for UDP-glucose and activates CalS even in the presence of permeabilizing concentrations of digitonin. Inhibition studies with UDP-pyridoxal indicate that activation by CHAPS occurs by recruitment of previously inactive CalS molecules to the pool of active enzyme. The activation of pollen tube CalS by these detergents therefore resembles activation of the enzyme by trypsin. PMID:9276948

Impact of heavy metals on hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. Coli.

PubMed

Sharma, Preeti; Melkania, Uma

2018-05-01

In the present study, the effect of heavy metals (lead, mercury, copper, and chromium) on the hydrogen production from the organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. Heavy metals were applied at concentration range of 0.5, 1, 2, 5, 10, 20, 50 and 100 mg/L. The results revealed that lead, mercury, and chromium negatively affected hydrogen production for the range of concentrations applied. Application of copper slightly enhanced hydrogen production at low concentration and resulted in the hydrogen yield of 36.0 mLH 2 /gCarbo initial with 10 mg/L copper supplementation as compared to 24.2 mLH 2 /gCarbo initial in control. However, the higher concentration of copper (>10 mg/L) declined hydrogen production. Hydrogen production inhibition potential of heavy metals can be arranged in the following increasing order: Cu 2+  < Cr 6+  < Pb 2+  < Hg 2+ . COD removal rate and volatile fatty acid generation efficiencies were also significantly affected by heavy metal addition. Thus, the present study reveals that the presence of heavy metals in the feedstock is detrimental for the hydrogen production. Therefore, it is essential to remove the toxic heavy metals prior to anaerobic digestion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of zinc ions on nutrient removal and growth of Lemna aequinoctialis from anaerobically digested swine wastewater.

PubMed

Zhou, Qi; Lin, Yan; Li, Xiang; Yang, Chunping; Han, Zhenfeng; Zeng, Guangming; Lu, Li; He, Shanying

2018-02-01

The effect of Zn 2+ on ammonium and phosphorous removal and duckweed growth was evaluated for treatment of anaerobically digested swine wastewater (ADSW) at various initial Zn 2+ concentrations ranging from 1.0 to 15mg/L. Lemna aequinoctialis taken from a local pond was selected for the treatment, and its fresh weight and contents of proteins, photosynthetic pigments, and vitamin E were examined. Results showed that the optimal Zn 2+ concentration was 5.0mg/L for NH 3 -N and TP removal, the duckweed growth, and the accumulation of proteins in the duckweed. A maximum content of photosynthetic pigments increased with the increase of initial Zn 2+ concentration, and it arrived earlier for a higher concentration of Zn 2+ . Vitamin E content in the duckweed reached 4.5mg/kg at 15mg/L Zn 2+ in 12-day cultivation, which showed the potential for producing and harvesting a high value-added product of vitamin E by culturing duckweed in ADSW. Copyright © 2017 Elsevier Ltd. All rights reserved.

iron phase control during pressure leaching at elevated temperature

NASA Astrophysics Data System (ADS)

Fleuriault, Camille

Iron is a common contaminant encountered in most metal recovery operations, and particularly hydrometallurgical processes. For example, the Hematite Process uses autoclaves to precipitate iron oxide out of the leaching solution, while other metals are solubilized for further hydrometallurgical processing. In some cases, Basic Iron Sulfate (BIS) forms in place of hematite. The presence of BIS is unwanted in the autoclave discharge because it diminishes recovery and causes environmental matters. The focus of this master thesis is on the various iron phases forming during the pressure oxidation of sulfates. Artificial leaching solutions were produced from CuSO4, FeSO4 and H2SO4 in an attempt to recreate the matrix composition and conditions used for copper sulfides autoclaving. The following factors were investigated in order to determine which conditions hinder the formation of BIS: initial free acidity (5 -- 98 g/L), initial copper concentration (12.7 -- 63.5 g/L), initial iron concentration (16.7 -- 30.7 g/L) and initial iron oxidation state. There were three solid species formed in the autoclave: hematite, BIS and hydronium jarosite. The results show that free acid is the main factor influencing the composition of the residue. At an initial concentration of 22.3 g/L iron and no copper added, the upper limit for iron oxide formation is 41 g/L H2SO4. The increase of BIS content in the residue is not gradual and occurs over a change of a few grams per liter around the aforementioned limit. Increasing copper sulfate concentration in the solution hinders the formation of BIS. At 63.5g/L copper, the upper free acidity limit is increased to 61g/L. This effect seems to be related to the buffering action of copper sulfate, decreasing the overall acid concentration and thus extending the stability range of hematite. The effect of varying iron concentration on the precipitate chemistry is unclear. At high iron levels, the only noticeable effect was the inhibition of jarosite. The results were reported within a Cu-Fe-S ternary system and modeled. The modeling confirmed the experimental observations with the exception that increasing iron concentrations seem to promote BIS stability.

Uptake of perfluorinated compounds by plants grown in nutrient solution.

PubMed

García-Valcárcel, A I; Molero, E; Escorial, M C; Chueca, M C; Tadeo, J L

2014-02-15

The uptake rates of three perfluorinated carboxylates and three perfluorinated sufonates by a grass (B diandrus) grown in nutrient solution at two different perfluorinated compounds (PFCs) concentrations were assessed. Grass can be ingested by grazing animals causing the PFCs to enter the food chain, which is a pathway of human exposure to these compounds. A rapid and miniaturized method was developed to determine PFCs in plants, based on a matrix solid-phase dispersion (MSPD) extraction procedure followed by quantitation by HPLC-MS/MS with an MQL in the range from 1 to 9 ng/g. An increase of PFCs levels in plant was observed along the exposure time. Differences in uptake for studied perfluorinated carboxylates were found, showing a decrease with carbon chain length (from 3027 to 1,167 ng/g at the end of assay), whereas no significant differences in absorption were obtained between perfluorinated sulfonates (about 1,700 ng/g). Initially, higher PFC transfer factors (ratio between concentration in plant and concentration in initial nutrient solution) were obtained for plants growing in the nutrient solution at the highest PFC concentration, but these factors became similar with time to plants exposed to the lowest concentration. © 2013 Elsevier B.V. All rights reserved.

Biosorption of lead by citrobacter freundii immobilized on hazelnut shells

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

Bueyuekguengoer, H.; Wilk, M.; Schubert, H.

1996-12-31

Biosorption of lead from aqueous solutions by living and immobilized cell of C. freundii was examined as a function of metal concentration in a batch laboratory bioreactor. Lead concentrations were analyzed using Atomic Absorption Spectrophotometer (AAS). X-ray Energy Dispersion (EDX) analyses were made in order to determine the accumulation of lead on the cells and shell surfaces. Before and after the experiments the biomaterials and adsorbents were examined by Scanning Electron Microscopy (SEM). Biosorption was detected over a range of initial lead concentrations from 25{times}10{sup -3} to 200{times}10{sup -3} kg/m{sup 3}. 15 refs., 4 figs.

Monitoring of Low-Level Virus in Natural Waters

PubMed Central

Sorber, Charles A.; Sagik, Bernard P.; Malina, Joseph F.

1971-01-01

The insoluble polyelectrolyte technique for concentrating virus is extended to extremely low virus levels. The effectiveness of this method employing a coliphage T2 model is a constant 20% over a range of virus levels from 103 to 10−4 plaque-forming units/ml. The efficiency of the method is dependent upon pH control during the concentration phase. Although the study was initiated to develop a method for quantitating the effectiveness of water and wastewater treatment methods for the removal of viruses from waters at low concentrations, the potential of the technique for efficient monitoring of natural waters is apparent. PMID:4940873

Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process.

PubMed

Arrizon, Javier; Gschaedler, Anne

2002-11-01

In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g x L(-1). In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g x L(-1)) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.

Injection-salting of pre rigor fillets of Atlantic salmon (Salmo salar).

PubMed

Birkeland, Sveinung; Akse, Leif; Joensen, Sjurdur; Tobiassen, Torbjørn; Skåra, Torstein

2007-01-01

The effects of temperature (-1, 4, and 10 degrees C), brine concentration (12% and 25% NaCl), injection volumes, and needle densities were investigated on fillet weight gain (%), salt content (%), fillet contraction (%), and muscle gaping in pre rigor brine-injected fillets of Atlantic salmon (Salmo salar). Increased brine concentration (12% to 25%) significantly increased the initial (< 5 min after injection) and final contraction (24 h after injection) of pre rigor fillets. Increased brine concentration significantly reduced weight gain and increased salt content but had no significant effect on muscle gaping. The temperatures tested did not significantly affect weight gain, fillet contraction, or gaping score. Significant regressions (P < 0.01) between the injection volume and weight gain (range: 2.5% to 15.5%) and salt content (range: 1.7% to 6.5%) were observed for injections of pre rigor fillets. Double injections significantly increased the weight gain and salt content compared to single injections. Initial fillet contraction measured 30 min after brine injection increased significantly (P < 0.01) with increasing brine injection volume but no significant difference in the fillet contraction was observed 12 h after brine injection (range: 7.9% to 8.9%). Brine-injected post rigor control fillets obtained higher weight gain, higher salt content, more muscle gaping, and significantly lower fillet contraction compared to the pre rigor injected fillets. Injection-salting is an applicable technology as a means to obtain satisfactory salt contents and homogenously distribute the salt into the muscle of pre rigor fillets of Atlantic salmon before further processing steps such as drying and smoking.

Volatile Concentrations in Pyroclastic Obsidian: Two Case Studies

NASA Astrophysics Data System (ADS)

Wearn, K. M.; Cashman, K. V.; Wallace, P. J.

2002-12-01

Pyroclastic obsidian is abundant in fall deposits associated with Mt. Mazama's Cleetwood eruption and South Sister's Rock Mesa eruption. Measured concentrations of H2Ototal and CO2 in >300 obsidian samples from these two eruptions provide important information about both the style of degassing (open- vs. closed-system) and changes in eruptive conditions through the course of both eruptions. Obsidian clasts preserve a range of total H2O contents, with samples from lower stratigraphic levels displaying a wider range of water concentrations than those from the uppermost tephra layer sampled. All samples from the Cleetwood section contain <=1 wt% water, with those from the top of that deposit containing <0.4 wt%. Obsidian from the basal ash layer of the subsequent climactic eruption contains 0.1 - 0.8 wt% water. Obsidian fragments from the Rock Mesa eruption show a broader range in H2Ototal contents (from 0.1 to >3 wt%) than those from the Cleetwood eruption. At Rock Mesa, maximum total water contents generally decrease with increased stratigraphic height. However, this decrease is not strictly monotonic: fluctuations in maximum total water contents correspond to stratigraphic unit boundaries. In addition, the Rock Mesa event produced abundant obsidian with very low H2Ototal concentrations throughout the eruption. Dissolved molecular CO2 levels are below the detection limit in all of the Cleetwood and Mazama samples. This is not surprising, given the low initial CO2 measured in Cleetwood and Mazama melt inclusions by Bacon et al. (1992). CO2 concentrations in the Rock Mesa clasts range from <5 ppm to ~44 ppm, and are positively correlated with H2Ototal concentrations. Fluorine concentrations in Cleetwood and Mazama climactic obsidian clasts vary between ~510 and ~695 ppm, with climactic samples averaging slightly lower concentrations than Cleetwood samples. Fluorine concentrations in Rock Mesa obsidians are uniformly low (~300 to ~510 ppm). Chlorine contents of Cleetwood and Mazama climactic samples range from ~1400 ppm to ~1610 ppm. The Rock Mesa samples all contain less chlorine (~510 to ~1120 ppm) than the Cleetwood and climactic samples, and in the Rock Mesa obsidian, chlorine and total water are positively correlated. Stratigraphic variations in the volatile contents of pyroclastic obsidian support previous work suggesting that obsidian forms along the margins of the volcanic conduit and is eroded from the conduit walls by fragmenting magma. Both the Cleetwood and the Rock Mesa deposits indicate initial evacuation of shallow vanguard magma followed by a rapid increase in fragmentation depth. Both deposits also show a gradual decrease in the fragmentation depth through time, consistent with subsequent effusive activity in both cases. More puzzling is the apparent closed-system degassing trend defined by the H2O-CO2-Cl relations in the Rock Mesa obsidian samples, despite the loss of volatiles required for obsidian formation. This suggests that volatile data may also provide information on the relative time scales of volatile exsolution and loss and obsidian formation.

Encapsulation of ascorbyl palmitate in chitosan nanoparticles by oil-in-water emulsion and ionic gelation processes.

PubMed

Yoksan, Rangrong; Jirawutthiwongchai, Jatesuda; Arpo, Kridsada

2010-03-01

The encapsulation of ascorbyl palmitate (AP) in chitosan particles was carried out by droplet formation via an oil-in-water emulsion, followed by droplet solidification via ionic gelation using sodium triphosphate pentabasic (TPP) as a cross-linking agent. The success of AP encapsulation was confirmed by FT-IR, UV-vis spectrophotometry, TGA, and XRD techniques. The obtained AP-loaded chitosan particles were spherical in shape with an average diameter of 30-100nm as observed by SEM and TEM. Loading capacity (LC) and encapsulation efficiency (EE) of AP in the nanoparticles were about 8-20% and 39-77%, respectively, when the initial AP concentration was in the range of 25-150% (w/w) of chitosan. Augmentation of the initial AP concentration led to an increase of LC and a reduction of EE. The amount of AP released from the nanoparticles in ethanol and tris buffer (pH approximately 8.0) increased with increasing LC and decreasing TPP concentration.

Ozone-initiated disinfection kinetics of Escherichia coli in water.

PubMed

Zuma, Favourite; Lin, Johnson; Jonnalagadda, Sreekanth B

2009-01-01

The effect of ozonation on the rate of disinfection of Escherichia coli was investigated as a function of ozone concentration, ozonation duration and flow rates. Ozone was generated in situ using Corona discharge method using compressed oxygen stream and depending on the oxygen flux the ozone concentrations ranged from 0.91-4.72 mg/L. The rate of disinfection of all the three microbes followed pseudo-first-order kinetics with respect to the microbe count and first order with respect to ozone concentration. The influence of pH and temperature the aqueous systems on the rate of ozone initiated disinfection of the microbe was investigated. The inactivation was faster at lower pH than at basic pH. Molecular ozone is found more effective in disinfection than hydroxyl radicals. Two reported mechanisms for antimicrobial activity of ozone in water systems from the literature are discussed. Based on the experimental findings a probable rate law and mechanism are proposed. Ozonation of natural waters significantly decreased the BOD levels of the control and microbe contaminated waters.

Interactions of tissue and fertilizer nitrogen on decomposition dynamics of lignin-rich conifer litter

USGS Publications Warehouse

Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

2012-01-01

High tissue nitrogen (N) accelerates decomposition of high-quality leaf litter in the early phases of mass loss, but the influence of initial tissue N variation on the decomposition of lignin-rich litter is less resolved. Because environmental changes such as atmospheric N deposition and elevated CO2 can alter tissue N levels within species more rapidly than they alter the species composition of ecosystems, it is important to consider how within-species variation in tissue N may shape litter decomposition and associated N dynamics. Douglas-fir (Pseudotsuga menziesii ) is a widespread lignin-rich conifer that dominates forests of high carbon (C) storage across western North America, and displays wide variation in tissue and litter N that reflects landscape variation in soil N. We collected eight unique Douglas-fir litter sources that spanned a two-fold range in initial N concentrations (0.67–1.31%) with a narrow range of lignin (29–35%), and examined relationships between initial litter chemistry, decomposition, and N dynamics in both ambient and N fertilized plots at four sites over 3 yr. High initial litter N slowed decomposition rates in both early (0.67 yr) and late (3 yr) stages in unfertilized plots. Applications of N fertilizer to litters accelerated early-stage decomposition, but slowed late-stage decomposition, and most strongly affected low-N litters, which equalized decomposition rates across litters regardless of initial N concentrations. Decomposition of N-fertilized litters correlated positively with initial litter manganese (Mn) concentrations, with litter Mn variation reflecting faster turnover of canopy foliage in high N sites, producing younger litterfall with high N and low Mn. Although both internal and external N inhibited decomposition at 3 yr, most litters exhibited net N immobilization, with strongest immobilization in low-N litter and in N-fertilized plots. Our observation for lignin-rich litter that high initial N can slow decomposition yet accelerate N release differs from findings where litter quality variation across species promotes coupled C and N release during decomposition. We suggest reevaluation of ecosystem models and projected global change effects to account for a potential decoupling of ecosystem C and N feedbacks through litter decomposition in lignin-rich conifer forests.

Adsorption characteristics of selected pharmaceuticals and an endocrine disrupting compound-Naproxen, carbamazepine and nonylphenol-on activated carbon.

PubMed

Yu, Zirui; Peldszus, Sigrid; Huck, Peter M

2008-06-01

The adsorption of two representative pharmaceutically active compounds (PhACs) (naproxen and carbamazepine) and one endocrine disrupting compound (nonylphenol) were evaluated on two types of activated carbon. When determining their isotherms at environmentally relevant concentration levels, it was found that at this low concentration range (10-800 ng/L), removals of the target compounds were contrary to expectations based on their hydrophobicity. Nonylphenol (log K(ow) 5.8) was most poorly adsorbed, whereas carbamazepine (log K(ow) 2.45) was most adsorbable. Nonylphenol Freundlich isotherms at this very low concentration range had a much higher 1/n compared to isotherms at much higher concentrations. This indicates that extrapolation from an isotherm obtained at a high concentration range to predict the adsorption of nonylphenol at a concentration well below the range of the original isotherm, leads to a substantial overestimation of its removals. Comparison of isotherms for the target compounds to those for other conventional micropollutants suggested that naproxen and carbamazepine could be effectively removed by applying the same dosage utilized to remove odorous compounds (geosmin and MIB) at very low concentrations. The impact of competitive adsorption by background natural organic matter (NOM) on the adsorption of the target compounds was quantified by using the ideal adsorbed solution theory (IAST) in combination with the equivalent background compound (EBC) approach. The fulfilment of the requirements for applying the simplified IAST-EBC model, which leads to the conclusion that the percentage removal of the target compounds at a given carbon dosage is independent of the initial contaminant concentration, was confirmed for the situation examined in the paper. On this basis it is suggested that the estimated minimum carbon usage rates (CURs) to achieve 90% removal of these emerging contaminants would be valid at concentrations of less than 500 ng/L in natural water.

Hospital protocols for targeted glycemic control: Development, implementation, and models for cost justification.

PubMed

Magee, Michelle F

2007-05-15

Evolving elements of best practices for providing targeted glycemic control in the hospital setting, clinical performance measurement, basal-bolus plus correction-dose insulin regimens, components of standardized subcutaneous (s.c.) insulin order sets, and strategies for implementation and cost justification of glycemic control initiatives are discussed. Best practices for targeted glycemic control should address accurate documentation of hyperglycemia, initial patient assessment, management plan, target blood glucose range, blood glucose monitoring frequency, maintenance of glycemic control, criteria for glucose management consultations, and standardized insulin order sets and protocols. Establishing clinical performance measures, including desirable processes and outcomes, can help ensure the success of targeted hospital glycemic control initiatives. The basal-bolus plus correction-dose regimen for insulin administration will be used to mimic the normal physiologic pattern of endogenous insulin secretion. Standardized insulin order sets and protocols are being used to minimize the risk of error in insulin therapy. Components of standardized s.c. insulin order sets include specification of the hyperglycemia diagnosis, finger stick blood glucose monitoring frequency and timing, target blood glucose concentration range, cutoff values for excessively high or low blood glucose concentrations that warrant alerting the physician, basal and prandial or nutritional (i.e., bolus) insulin, correction doses, hypoglycemia treatment, and perioperative or procedural dosage adjustments. The endorsement of hospital administrators and key physician and nursing leaders is needed for glycemic control initiatives. Initiatives may be cost justified on the basis of the billings for clinical diabetes management services and/or the return- on-investment accrued to reductions in hospital length of stay, readmissions, and accurate documentation and coding of unrecognized or uncontrolled diabetes, and diabetes complications. Standardized insulin order sets and protocols may minimize risk of insulin errors. The endorsement of these protocols by administrators, physicians, nurses, and pharmacists is also needed for success.

Shock-tube thermochemistry tables for high-temperature gases. Volume 5: Carbon dioxide

NASA Technical Reports Server (NTRS)

Menard, W. A.; Horton, T. E.

1971-01-01

Equilibrium thermodynamic properties and species concentrations for carbon dioxide are tabulated for moving, standing, and reflected shock waves. Initial pressures range from 6.665 to 6665 N/sq m (0.05 to 50.0 torr), and temperatures from 2,000 to over 80,000K. In this study, 20 molecular and atomic species were considered.

Mercury in water and biomass of microbial communities in hot springs of Yellowstone National Park, USA

USGS Publications Warehouse

King, S.A.; Behnke, S.; Slack, K.; Krabbenhoft, D.P.; Nordstrom, D. Kirk; Burr, M.D.; Striegl, Robert G.

2006-01-01

Ultra-clean sampling methods and approaches typically used in pristine environments were applied to quantify concentrations of Hg species in water and microbial biomass from hot springs of Yellowstone National Park, features that are geologically enriched with Hg. Microbial populations of chemically-diverse hot springs were also characterized using modern methods in molecular biology as the initial step toward ongoing work linking Hg speciation with microbial processes. Molecular methods (amplification of environmental DNA using 16S rDNA primers, cloning, denatured gradient gel electrophoresis (DGGE) screening of clone libraries, and sequencing of representative clones) were used to examine the dominant members of microbial communities in hot springs. Total Hg (THg), monomethylated Hg (MeHg), pH, temperature, and other parameters influential to Hg speciation and microbial ecology are reported for hot springs water and associated microbial mats. Several hot springs indicate the presence of MeHg in microbial mats with concentrations ranging from 1 to 10 ng g-1 (dry weight). Concentrations of THg in mats ranged from 4.9 to 120,000 ng g-1 (dry weight). Combined data from surveys of geothermal water, lakes, and streams show that aqueous THg concentrations range from l to 600 ng L-1. Species and concentrations of THg in mats and water vary significantly between hot springs, as do the microorganisms found at each site. ?? 2006.

Degradation of sulfamethazine by gamma irradiation in the presence of hydrogen peroxide.

PubMed

Liu, Yuankun; Wang, Jianlong

2013-04-15

The gamma irradiation-induced degradation of sulfamethazine (SMT) in aqueous solution in the presence of hydrogen peroxide (H2O2) was investigated. The initial SMT concentration was 20mg/L and it was irradiated in the presence of extra H2O2 with initial concentration of 0, 10 and 30 mg/L. The results showed that gamma irradiation was effective for removing SMT in aqueous solution and its degradation conformed to the pseudo first-order kinetics under the applied conditions. When initial H2O2 concentration was in the range of 0-30 mg/L, higher concentration of H2O2 was more effective for the decomposition and mineralization of SMT. However, the removal of total organic carbon (TOC) was not as effective as that of SMT. Total nitrogen (TN) was not removed even at absorbed dose of 5 kGy, which was highest dose applied in this study. Major decomposition products of SMT, including degradation intermediates, organic acids and some inorganic ions were detected by high performance liquid chromatography (HPLC) and ion chromatography (IC). Sulfate (SO4(2-)), formic acid (HCOOH), acetic acid (CH3COOH), 4-aminophenol, 4-nitrophenol were identified in the irradiated solutions. Possible pathways for SMT decomposition by gamma irradiation in aqueous solution were proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

Geochemical characterization of water, sediment, and biota affected by mercury contamination and acidic drainage from historical gold mining, Greenhorn Creek, Nevada County, California, 1999-2001

USGS Publications Warehouse

Alpers, Charles N.; Hunerlach, Michael P.; May, Jason T.; Hothem, Roger L.; Taylor, Howard E.; Antweiler, Ronald C.; De Wild, John F.; Lawler, David A.

2005-01-01

In 1999, the U.S. Geological Survey (USGS) initiated studies of mercury and methylmercury occurrence, transformation, and transport in the Bear River and Yuba River watersheds of the northwestern Sierra Nevada. Because these watersheds were affected by large-scale, historical gold extraction using mercury amalgamation beginning in the 1850s, they were selected for a pilot study of mercury transport by the USGS and other cooperating agencies. This report presents data on methylmercury (MeHg) and total mercury (THg) concentrations in water, bed sediment, invertebrates, and frogs collected at 40 stations during 1999-2001 in the Greenhorn Creek drainage, a major tributary to Bear River. Results document several mercury contamination ?hot spots? that represent potential targets for ongoing and future remediation efforts at abandoned mine sites in the study area. Water-quality samples were collected one or more times at each of 29 stations. The concentrations of total mercury in 45 unfiltered water samples ranged from 0.80 to 153,000 nanograms per liter (ng/L); the median was 9.6 ng/L. Total mercury concentrations in filtered water (41 samples) ranged from less than 0.3 to 8,000 ng/L; the median was 2.7 ng/L. Concentrations of methylmercury in the unfiltered water (40 samples) ranged from less than 0.04 to 9.1 ng/L; the median was 0.07 ng/L. Methylmercury in filtered water (13 samples) ranged from less than 0.04 to 0.27 ng/L; the median was 0.04 ng/L. Acidic drainage with pH values as low as 3.4 was encountered in some of the mined areas. Elevated concentrations of aluminum, cadmium, copper, iron, manganese, nickel, and zinc were found at several stations, especially in the more acidic water samples. Total mercury concentrations in sediment were determined by laboratory and field methods. Total mercury concentrations (determined by laboratory methods) in ten samples from eight stations ranged from about 0.0044 to 12 ?g/g (microgram per gram, equivalent to parts per million). Methylmercury concentrations in these samples ranged from less than 0.00011 to 0.0095 ?g/g. A field panning method was used to determine the concentration of liquid elemental mercury in 22 samples from 14 stations. Measured quantities of elemental mercury recovered by panning ranged from a trace amount estimated at 100 milligrams per kilogram (equivalent to parts per million) to 45,000 milligrams per kilogram (equivalent to 4.5 per cent, by weight). In total, 194 invertebrate samples were collected at 31 stations; 78 of the samples were analyzed for concentrations of THg and MeHg and used to calculate MeHg to THg ratios. A total of 69 frog samples were collected at 19 stations, and all were analyzed only for THg. Ranges of MeHg concentrations (?g/g, wet weight) in invertebrate samples and number of samples (n) were 0.0012-0.048 for banana slugs (Arionidae, n = 27), 0.027-0.39 for dobsonflies (Corydalidae, n = 14), 0.029-0.50 for predaceous diving beetles (Dytiscidae, n = 31), 0.026-0.52 for predaceous stoneflies (Perlidae, n = 18), 0.011-1.6 for dragonflies (Odonata, n = 46), and 0.061-0.55 for water striders (Gerridae, n = 56). The ratio of MeHg to THg in invertebrates was greater than 50 percent for 74 of 78 samples. The data from this reconnaissance sampling effort have been used by land-management agencies in selecting abandoned mine sites for remediation. The Forest Service has remediated the Sailor Flat site, and the Bureau of Land Management has initiated plans to remediate the Boston Mine drainage tunnel.

Northern peatland initiation lagged abrupt increases in deglacial atmospheric CH4.

PubMed

Reyes, Alberto V; Cooke, Colin A

2011-03-22

Peatlands are a key component of the global carbon cycle. Chronologies of peatland initiation are typically based on compiled basal peat radiocarbon (14C) dates and frequency histograms of binned calibrated age ranges. However, such compilations are problematic because poor quality 14C dates are commonly included and because frequency histograms of binned age ranges introduce chronological artefacts that bias the record of peatland initiation. Using a published compilation of 274 basal 14C dates from Alaska as a case study, we show that nearly half the 14C dates are inappropriate for reconstructing peatland initiation, and that the temporal structure of peatland initiation is sensitive to sampling biases and treatment of calibrated 14C dates. We present revised chronologies of peatland initiation for Alaska and the circumpolar Arctic based on summed probability distributions of calibrated 14C dates. These revised chronologies reveal that northern peatland initiation lagged abrupt increases in atmospheric CH4 concentration at the start of the Bølling-Allerød interstadial (Termination 1A) and the end of the Younger Dryas chronozone (Termination 1B), suggesting that northern peatlands were not the primary drivers of the rapid increases in atmospheric CH4. Our results demonstrate that subtle methodological changes in the synthesis of basal 14C ages lead to substantially different interpretations of temporal trends in peatland initiation, with direct implications for the role of peatlands in the global carbon cycle.

Potential impact of initialization on decadal predictions as assessed for CMIP5 models

NASA Astrophysics Data System (ADS)

Branstator, Grant; Teng, Haiyan

2012-06-01

To investigate the potential for initialization to improve decadal range predictions, we quantify the initial value predictability of upper 300 m temperature in the two northern ocean basins for 12 models from Coupled Model Intercomparison Project phase 5 (CMIP5), and we contrast it with the forced predictability in Representative Concentration Pathways (RCP) 4.5 climate change projections. We use a recently introduced method that produces predictability estimates from long control runs. Many initial states are considered, and we find on average 1) initialization has the potential to improve skill in the first 5 years in the North Pacific and the first 9 years in the North Atlantic, and 2) the impact from initialization becomes secondary compared to the impact of RCP4.5 forcing after 6 1/2 and 8 years in the two basins, respectively. Model-to-model and spatial variations in these limits are, however, substantial.

Reconnaissance investigations of potential ground-water and sediment contamination at three former underground storage tank locations, Fort Jackson, South Carolina, 1994

USGS Publications Warehouse

Robertson, J.F.; Nagle, Douglas D.; Rhodes, Liesl C.

1994-01-01

Investigations to provide initial qualitative delineation of petroleum hydrocarbon contamination at three former underground storage tank locations at Fort Jackson, South Carolina, were made during March 1994. Ground-water and sediment samples were collected using direct-push technology and analyzed on-site with a gas chromatograph, which provided real-time, semi-quantitative data. In addition, ground-water and sediment samples were collected at selected sites for laboratory analyses to provide a confirmation of the on-site data. These analyses provided qualitative data on the lateral distri- bution of petroleum hydrocarbons. Petroleum hydrocarbons were detected by on-site analysis in ground-water samples from nine locations at Site 1062, suggesting the presence of a contaminant plume. Concentrations ranged from less than the minimum detection limit to 4,511 mg/L (micrograms per liter) for benzene, 15,594 mg/L for toluene, 16,501 mg/L for ethylbenzene, and 19,391 mg/L for total xylenes. Concentrations of Total Petroleum Hydrocarbons-Gasoline Range Organics ranged from 323 mg/L to 3,364 mg/L; Total Petroleum Hydrocarbons-Diesel Range Organics were not detected. Three samples from this site were analyzed for benzene, toluene, ethylbenzene, and total xylenes at a laboratory and results showed concentrations ranging from less than the minimum detection limit to 1,070 mg/L for benzene, 7,930 mg/L for toluene, 6,890 mg/L for ethylbenzene, and 1,524 mg/L for total xylenes. Petroleum hydro- carbons were detected by on-site analysis in only one sample at Site 2438. A concentration of 131,000 micrograms per kilogram Total Petroleum Hydrocarbons-Diesel Range Organics was detected in sample number GP-2-4-13.5. Petroleum hydrocarbons were detected by on-site analysis in only one ground-water sample from Site 2444. A concentration of 3,145 mg/L Total Petroleum Hydrocarbons-Gasoline Range Organics was detected at sampling location GP-3-2.

Management of early renal anaemia: diagnostic work-up, iron therapy, epoetin therapy.

PubMed

Van Wyck, D B

2000-01-01

Effective management of early anaemia in the course of chronic renal insufficiency requires the following: (i) implementing an efficient diagnostic strategy to exclude common contributing factors; (ii) initiating epoetin therapy for the majority of patients; for and (iii) ensuring adequate iron supply erythropoiesis. Diagnostic inquiry is warranted whenever the haemoglobin concentration is below the normal range adjusted for age and gender. The most efficient diagnostic approach is to assume erythropoietin deficiency, exclude iron deficiency, and pursue further diagnostic tests only when red-cell indices are abnormal or when leukopenia or thrombocytopenia are also present. Macrocytosis should prompt an inquiry into alcoholism, B12 deficiency, or folate deficiency. Microcytosis suggests iron deficiency or thalassaemia. Associated cytopenias raise the possibility of alcohol toxicity, pernicious anaemia, malignancy, or myelodysplastic syndrome. Epoetin therapy is warranted whenever the haemoglobin concentration has fallen below 10.0 g/dl. To initiate therapy prior to dialysis, epoetin should be administered at an average dose of 100 IU/kg/week (80-120 IU/kg/week, 50-150 IU/kg/ week) by subcutaneous injection. Haemoglobin concentration should be monitored every 2 weeks and the epoetin dose adjusted by increments or decrements of 25% to maintain a rate of rise of haemoglobin concentration of 0.2-0.6 g/dl (0.3 0.6 g/dl/week, 0.2-0.5 g/dl/week). When the target range is achieved, the dose of epoetin should be continually adjusted to maintain a stable haemoglobin concentration. Transferrin saturation and ferritin concentration should be monitored monthly, and sufficient iron provided to maintain transferrin saturation above 20%. The lower the haemoglobin concentration, the greater the likelihood that future intravenous iron will be required. Oral iron supplements should be avoided, since they are costly, ineffective, and troublesome to patients. Finally, a blunted therapeutic response to epoetin therapy provides important diagnostic information and gnostic inquiry.

The Effect of Initial Cell Concentration on Xylose Fermentation by Pichia stipitis

NASA Astrophysics Data System (ADS)

Agbogbo, Frank K.; Coward-Kelly, Guillermo; Torry-Smith, Mads; Wenger, Kevin; Jeffries, Thomas W.

Xylose was fermented using Pichia stipitis CBS 6054 at different initial cell concentrations. A high initial cell concentration increased the rate of xylose utilization, ethanol formation, and the ethanol yield. The highest ethanol concentration of 41.0 g/L and a yield of 0.38 g/g was obtained using an initial cell concentration of 6.5 g/L. Even though more xylitol was produced when the initial cell concentrations were high, cell density had no effect on the final ethanol yield. A two-parameter mathematical model was used to predict the cell population dynamics at the different initial cell concentrations. The model parameters, a and b correlate with the initial cell concentrations used with an R 2 of 0.99.

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

Dai, X.; Antal, M.J. Jr.

Macadamia nut shell charcoal was heated in an inert environment to temperatures above 1000 K (carbonized), reacted with oxygen (Po{sub 2} = 2.68--11.3 kPa) at temperatures between 525 and 586 K (oxygenated), and heated again in an inert environment to temperatures above 1000 K (activated) to produce an activated carbon. Carbons produced by this process possess surface areas and iodine numbers in the range of 400--550. Overall yields of these carbons (based on the dry, raw macadamia nut shell feed) ranged from 24 to 30 wt %. Under the conditions employed in this work, the rates of chemisorption and gasificationmore » were not mass transfer limited. Initially, the gasification reaction was first-order with respect to oxygen concentration but became independent of oxygen concentration as the surface sites of the carbon became saturated with oxygen.« less

The Study of Compact Plasma Source of SXR of Vacuum Spark Type with Capillary Concentrator and It's Application

NASA Astrophysics Data System (ADS)

Kantsyrev, V. L.; Kopytok, K. I.; Shlyaptseva, A. S.

1994-03-01

The results are presented dealing with the working out and study of the plasma source of soft X-ray (SXR) of the new type. Experimental set up included compact low-inductance vacuum spark (LIVS) with initial energy supply equal up to 2.5 kJ and glass-capillary concentrator (GCC) of SXR. The characteristics of SXR of vacuum spark and properties of SXR were studied using diagnostic complex. The coefficient of conversion of initial energy supply into SXR (η) amounted to 0.01 in range 1.2nm. Value η had peak dependence on atomic number of anode Za. The spectra were recorded belonging to Ne-like, F-like ions of Fe, Cu ions and He-like, H-like ions of Al, Ti, Fe. Glass capillary concentrator consists of about several hundreds glass capillaries Flux density of SXR in focusing spot was up to 105-106 Wt/cm, density of energy is up to 20-30 mJ/cm2 at diameter of SXR focusing spot equal to about 2-3mm in the range 0.7-1.0 nm. The plasma source of the new type is intended for X-ray microscopy, study of influence of SXR on the surface of solid state. It allows to carry out experiments making only on electron synchrotronic sources of SXR.

Time-dependent efficiency measurements of polymer solar cells with dye additives: unexpected initial increase of efficiency

NASA Astrophysics Data System (ADS)

Bandaccari, Kyle J.; Chesmore, Grace E.; Bugaj, Mitchel; Valverde, Parisa Tajalli-Tehrani; Barber, Richard P.; McNelis, Brian J.

2018-04-01

We report the effects of the addition of two azo-dye additives on the time-dependent efficiency of polymer solar cells. Although the maximum efficiencies of devices containing different amounts of dye do not vary greatly over the selected concentration range, the time dependence results reveal a surprising initial increase in efficiency in some samples. We observe this effect to be correlated with a leakage current, although a specific mechanism is not yet identified. We also present the measured lifetimes of these solar cells, and find that variations in dye concentrations produce a small effect at most. Characterization of the bulk heterojunction layer (active layer) morphology using atomic-force microscope (AFM) imaging reveals reordering patterns which suggest that the primary effects of the dyes arise via structural, not absorptive, characteristics.

Ampicillin Nanoparticles Production via Supercritical CO2 Gas Antisolvent Process.

PubMed

Esfandiari, Nadia; Ghoreishi, Seyyed M

2015-12-01

The micronization of ampicillin via supercritical gas antisolvent (GAS) process was studied. The particle size distribution was significantly controlled with effective GAS variables such as initial solute concentration, temperature, pressure, and antisolvent addition rate. The effect of each variable in three levels was investigated. The precipitated particles were analyzed with scanning electron microscopy (SEM) and Zetasizer Nano ZS. The results indicated that decreasing the temperature and initial solute concentration while increasing the antisolvent rate and pressure led to a decrease in ampicillin particle size. The mean particle size of ampicillin was obtained in the range of 220-430 nm by varying the GAS effective variables. The purity of GAS-synthesized ampicillin nanoparticles was analyzed in contrast to unprocessed ampicillin by FTIR and HPLC. The results indicated that the structure of the ampicillin nanoparticles remained unchanged during the GAS process.

A simple method for determination of carmine in food samples based on cloud point extraction and spectrophotometric detection.

PubMed

Heydari, Rouhollah; Hosseini, Mohammad; Zarabi, Sanaz

2015-01-01

In this paper, a simple and cost effective method was developed for extraction and pre-concentration of carmine in food samples by using cloud point extraction (CPE) prior to its spectrophotometric determination. Carmine was extracted from aqueous solution using Triton X-100 as extracting solvent. The effects of main parameters such as solution pH, surfactant and salt concentrations, incubation time and temperature were investigated and optimized. Calibration graph was linear in the range of 0.04-5.0 μg mL(-1) of carmine in the initial solution with regression coefficient of 0.9995. The limit of detection (LOD) and limit of quantification were 0.012 and 0.04 μg mL(-1), respectively. Relative standard deviation (RSD) at low concentration level (0.05 μg mL(-1)) of carmine was 4.8% (n=7). Recovery values in different concentration levels were in the range of 93.7-105.8%. The obtained results demonstrate the proposed method can be applied satisfactory to determine the carmine in food samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Preliminary screening oxidative degradation methyl orange using ozone/ persulfate

NASA Astrophysics Data System (ADS)

Aqilah Razali, Nur; Zulzikrami Azner Abidin, Che; An, Ong Soon; Ridwan, Fahmi Muhammad; Haqi Ibrahim, Abdul; Nasuha Sabri, Siti; Huan Kow, Su

2018-03-01

The present study focusing on the performances of advanced oxidation process by using ozonation method towards Methyl Orange based on the efficiency of colour removal and Chemical Oxygen Demand (COD) removal. Factorial design with response surface methodology (RSM) was used to evaluate the interaction between operational conditions, such as pH, initial concentration, contact time and persulfate dosage to obtain the optimum range conditions using a semi-batch reactor. The range of independent variables investigated were pH (3-11), initial concentration (100-500mg/L), contact time (10-50min) and persulfate dosage (20-100mM) while the response variables were colour removal and COD removal of Methyl Orange. The experimental results and statistical analysis showed all the parameters were significant. Thus, from this findings, optimization of operational conditions that had been suggested from the ozone/persulfate RSM analysis were (pH 3, 100 mg/L, 50min, 60mM) that would be produced 99% Colour Removal and 80% COD Removal and help in promoting an efficient ozonation process. The effect list data that showed the most contributed effects to increase the percentages of colour removal were pH and persulfate dosage whereas the contact time and initial concentration had the highest positive effects on the COD removal. Other than that, the interaction between pH, contact time and persulfate dosage were found to be the most influencing interaction. Therefore the least influencing interaction was interaction between persulfate dosage and pH. In this study, the correlation coefficient value R2 for colour removal and COD removal of Methyl Orange were R2= 0.9976 and R2= 0.9924 which suggested a good fit of the first-order regression model with the experimental data.

Modeling the cell-type dependence of diffusion-limited intracellular ice nucleation and growth during both vitrification and slow freezing

NASA Astrophysics Data System (ADS)

Yang, Geer; Zhang, Aili; Xu, Lisa X.; He, Xiaoming

2009-06-01

In this study, a set of models for predicting the diffusion-limited ice nucleation and growth inside biological cells were established. Both the heterogeneous and homogeneous nucleation mechanisms were considered in the models. Molecular mobility including viscosity and mutual diffusion coefficient of aqueous cryoprotectant (i.e., glycerol here) solutions was estimated using models derived from the free volume theory for glass transition, which makes it possible to predict the two most important physical properties (i.e., viscosity and mutual diffusion coefficient) over wide ranges of temperature and concentration as encountered in cryopreservation. After being verified using experimental data, the models were used to predict the critical cooling rate (defined as the cooling rate required so that the crystallized volume is less than 0.1% of the cell volume) as a function of the initial glycerol concentration in a number of cell types with different sizes. For slowing freezing, it was found that the required critical cooling rate is cell-type dependent with influences from cell size and the ice nucleation and water transport parameters. In general, the critical cooling rate does not change significantly with the initial glycerol concentration used and tends to be higher for smaller cells. For vitrification, the required critical cooling rate does change significantly with the initial glycerol concentration used and tends to decrease with the decrease in cell size. However, the required critical cooling rate can be similar for cells with very different sizes. It was further found that the thermodynamic and kinetic parameters for intracellular ice formation associated with different cells rather than the cell size per se significantly affect the critical cooling rates required for vitrification. For all cell types, it was found that homogeneous nucleation dominates at ultrafast cooling rates and/or high glycerol concentrations, whereas heterogeneous nucleation becomes important only during slow freezing with a low initial glycerol concentration (<1.5-2M), particularly for large cells such as mouse oocytes.

Effective method of continuous rocuronium administration based on effect-site concentrations using a pharmacokinetic/pharmacodynamic model during propofol-remifentanil anesthesia.

PubMed

Moriyama, Takahiro; Matsunaga, Akira; Nagata, Osamu; Enohata, Kei; Kamikawaji, Tomomi; Uchino, Erika; Kanmura, Yuichi

2015-08-01

Rocuronium bromide (Rb) is a rapid onset, intermediate-acting neuromuscular blocking agent that is suitable for continuous administration. The appropriate rate of rocuronium administration is, however, difficult to determine due to large interindividual differences in sensitivity to rocuronium. The aim of this study was to clarify whether the simulated rocuronium concentration at the time of recovery to %T1 > 0 % after the initial administration of rocuronium is a good indicator of optimal effect-site concentrations during continuous rocuronium administration. Twenty-one patients were anesthetized with propofol. After induction, Rb 0.6 mg/kg was administered intravenously, and nerve stimulation using the single stimulation mode was conducted every 15 s. When %T1 recovered to >0 % after the initial administration of Rb, the effect-site concentration of rocuronium, calculated by pharmacokinetic simulation with Wierda's set of parameters, was recorded and defined as the recovery concentration (Rb r.c.). The administration rate of rocuronium was adjusted to maintain the Rb r.c. during surgery. Rb administration was discontinued just before the end of surgery, and the recovery time until %T1 > 25 % was recorded. Plasma Rb concentrations were measured at 1 and 3 h after the initiation of continuous Rb administration. The mean Rb r.c. was 1.56 ± 0.35 μg/ml, with minimum and maximum values of 1.09 and 2.08 μg/ml, respectively. The %T1 did not increase above 10 % in any of the patients during continuous administration of Rb, and the recovery period to %T1 > 25 % ranged from 9 to 29 min. The effect-site concentrations of Rb calculated with Wierda's parameters significantly correlated with plasma concentrations (P < 0.01) at both 1 and 3 h after the initial administration of Rb. The results suggest that our method may be one of the most reliable protocols for the continuous administration of Rb described to date for maintaining suitable muscle relaxation during surgery without excessively prolonged effects.

Feasibility and preliminary safety of nitric oxide releasing solution as a treatment for bovine mastitis.

PubMed

Regev, Gilly; Martins, James; Sheridan, Michael P; Leemhuis, Jonathan; Thompson, James; Miller, Christopher

2018-06-01

Nitric oxide-releasing solution (NORS) is a liquid formulation that releases nitric oxide, a broad spectrum antimicrobial, single electron nitroxide radical. This solution was investigated as a potential antimicrobial treatment for bovine mastitis (BM). Three experiments were performed: a) NORS' effect on Staphylococcus aureus and Escherichia coli in an in vitro model; b) NORS' effect on milk obtained from dairy cows showing symptoms of clinical mastitis; and c) the consequences of administering NORS to healthy milking cattle using a dose-escalating in vivo study. Metabolite concentrations were estimated in their blood for methaemoglobin and nitrite; also, milk nitrite concentration and somatic cell count (SCC) were measured to study possible mammary gland inflammation following treatment. NORS lowered the bacterial concentration in all infected samples, in a time- and milk-diluted dependant fashion. Blood methemoglobin concentrations following treatment were all within the normal range for cattle. However, blood and milk nitrite concentrations increased initially but, during the next 24 h, returned to normal range, as did SCC, without any clinical signs of mammary gland inflammation. NORS, if shown to be effective, could be an alternative treatment for mastitis with a shorter clearance time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Study of the adsorption of Cd and Zn onto an activated carbon: Influence of pH, cation concentration, and adsorbent concentration

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

Seco, A.; Marzal, P.; Gabaldon, C.

1999-06-01

The single adsorption of Cd and Zn from aqueous solutions has been investigated on Scharlau Ca 346 granular activated carbon in a wide range of experimental conditions: pH, metal concentration, and carbon concentration. The results showed the efficiency of the activated carbon as sorbent for both metals. Metal removals increase on raising the pH and carbon concentration, and decrease on raising the initial metal concentration. The adsorption processes have been modeled using the surface complex formation (SCF) Triple Layer Model (TLM). The adsorbent TLM parameters were determined. Modeling has been performed assuming a single surface bidentate species or an overallmore » surface species with fractional stoichiometry. The bidentate stoichiometry successfully predicted cadmium and zinc removals in all the experimental conditions. The Freundlich isotherm has been also checked.« less

Adiponectin, adipocyte fatty acid binding protein, and epidermal fatty acid binding protein: proteins newly identified in human breast milk.

PubMed

Bronsky, Jirí; Karpísek, Michal; Bronská, Eva; Pechová, Marta; Jancíková, Barbora; Kotolová, Hana; Stejskal, David; Prusa, Richard; Nevoral, Jirí

2006-09-01

Breastfeeding may protect children from developing metabolic syndrome and other diseases later in life. We investigated novel proteins in human breast milk that might play a role in this process. We used ELISA to measure adiponectin, adipocyte and epidermal fatty acid binding proteins (AFABP, EFABP), and leptin concentrations in human breast milk obtained from 59 mothers 48 h after initiation of lactation. Using a questionnaire and medical records, we collected information about the mothers and newborns. Mean (SE) adiponectin concentrations in breast milk were 13.7 (0.8), range 3.9-30.4 microg/L; AFABP concentrations 26.7 (4.4), range 1.2-137.0 microg/L; EFABP concentrations 18.1 (1.4), range 0.8-47.0 microg/L; and leptin concentrations 0.50 (0.05), range 0-1.37 microg/L. We found a significant correlation between AFABP and EFABP concentrations (r = 0.593, P <0.0001). Maternal EFABP concentrations were significantly higher in mothers who delivered boys than in those who delivered girls [21.7 (2.3) vs 15.4 (1.7) microg/L, P = 0.028] and correlated with newborn birth weight (r = 0.266, P = 0.045). Maternal leptin correlated with body weight before pregnancy (r = 0.272, P = 0.043) and at delivery (r = 0.370, P = 0.005), body mass index before pregnancy (r = 0.397, P = 0.003) and at delivery (r = 0.498, P <0.0001), body weight gain during pregnancy (r = 0.267, P = 0.047), and newborn gestational age (r = 0.266, P = 0.048). Leptin was significantly lower in mothers who delivered preterm vs term babies [0.30 (0.09) vs 0.60 (0.05) ug/L, P = 0.026]. Concentrations of adiponectin, AFABP, and EFABP in human breast milk are related to nutritional variables of mothers and newborns and thus may play a role in the protective effects of breastfeeding.

EC-QCL mid-IR transmission spectroscopy for monitoring dynamic changes of protein secondary structure in aqueous solution on the example of β-aggregation in alcohol-denaturated α-chymotrypsin.

PubMed

Alcaráz, Mirta R; Schwaighofer, Andreas; Goicoechea, Héctor; Lendl, Bernhard

2016-06-01

In this work, a novel EC-QCL-based setup for mid-IR transmission measurements in the amide I region is introduced for monitoring dynamic changes in secondary structure of proteins. For this purpose, α-chymotrypsin (aCT) acts as a model protein, which gradually forms intermolecular β-sheet aggregates after adopting a non-native α-helical structure induced by exposure to 50 % TFE. In order to showcase the versatility of the presented setup, the effects of varying pH values and protein concentration on the rate of β-aggregation were studied. The influence of the pH value on the initial reaction rate was studied in the range of pH 5.8-8.2. Results indicate an increased aggregation rate at elevated pH values. Furthermore, the widely accessible concentration range of the laser-based IR transmission setup was utilized to investigate β-aggregation across a concentration range of 5-60 mg mL(-1). For concentrations lower than 20 mg mL(-1), the aggregation rate appears to be independent of concentration. At higher values, the reaction rate increases linearly with protein concentration. Extended MCR-ALS was employed to obtain pure spectral and concentration profiles of the temporal transition between α-helices and intermolecular β-sheets. Comparison of the global solutions obtained by the modelled data with results acquired by the laser-based IR transmission setup at different conditions shows excellent agreement. This demonstrates the potential and versatility of the EC-QCL-based IR transmission setup to monitor dynamic changes of protein secondary structure in aqueous solution at varying conditions and across a wide concentration range. Graphical abstract EC-QCL IR spectroscopy for monitoring protein conformation change.

Fuel alcohol biosynthesis by Zymomonas anaerobia: optimization studies

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

Kosaric, N.; Ong, S.L.; Duvnjak, Z.

1982-03-01

The optimum operating conditions for growth and ethanol production of Zymomonas anaerobia ATCC 29501 were established. The optimum pH range and temperature were found to be 5.0-6.0 and 35 degrees C, respectively. Based on the results obtained from the temperature optimization study, an Arrhenius-type temperature relationship for the specific growth rate was developed. The growth and ethanol production of this microbe also have been optimized in terms of concentrations of glucose, essential nutrients, and minerals. With optimum medium and operating conditions, an ethanol concentration of 96 g/L was obtained in 23 hours. Both growth and ethanol yield coefficients in dependencemore » on initial glucose concentrations were determined. (Refs. 16).« less

Optimization of biogenic methane production from coal

DOE PAGES

Fuertez, John; Nguyen, Van; McLennan, John D.; ...

2017-09-29

Given continuously increasing global energy needs, diversified efforts have been made to find and exploit new natural gas resources. These include coalbed methane (CBM), which represents an important global, unconventional source of natural gas. Efforts have been underway for some time to more effectively generate methane in-situ in coal plays by introduction of nutrients and/or microbial consortia. However, much is still to be learned about the limitations and environmental conditions that support microbial growth and are conducive to biogenic methane production from coal. Here we evaluated environmental conditions that led to increased methane production from subbituminous coal by introducing amore » foreign methanogenic consortium that included Methanobacterium sp. Furthermore, we used a central composite design (CCD) to explore a broad range of operational conditions, examine the effects of the important environmental factors, such as temperature, pH and salt concentration, and query a feasible region of operation to maximize methane production from coal. An anticipated detrimental effect of NaCl concentration on methane production was observed for the consortium assessed. The range of feasible operational conditions comprised initial pH values between 4.2 and 6.8, temperatures between 23 °C and 37 °C, and NaCl concentrations between 3.7 mg/cm 3 and 9.0 mg/cm 3. Coal biogasification was optimal for this consortium at an initial pH value of 5.5, at 30 °C, and at a NaCl concentration 3.7 mg/cm 3 (i.e., 145,165 ppm, which is 25.6 sft 3/ton).« less

Optimization of biogenic methane production from coal

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

Fuertez, John; Nguyen, Van; McLennan, John D.

Given continuously increasing global energy needs, diversified efforts have been made to find and exploit new natural gas resources. These include coalbed methane (CBM), which represents an important global, unconventional source of natural gas. Efforts have been underway for some time to more effectively generate methane in-situ in coal plays by introduction of nutrients and/or microbial consortia. However, much is still to be learned about the limitations and environmental conditions that support microbial growth and are conducive to biogenic methane production from coal. Here we evaluated environmental conditions that led to increased methane production from subbituminous coal by introducing amore » foreign methanogenic consortium that included Methanobacterium sp. Furthermore, we used a central composite design (CCD) to explore a broad range of operational conditions, examine the effects of the important environmental factors, such as temperature, pH and salt concentration, and query a feasible region of operation to maximize methane production from coal. An anticipated detrimental effect of NaCl concentration on methane production was observed for the consortium assessed. The range of feasible operational conditions comprised initial pH values between 4.2 and 6.8, temperatures between 23 °C and 37 °C, and NaCl concentrations between 3.7 mg/cm 3 and 9.0 mg/cm 3. Coal biogasification was optimal for this consortium at an initial pH value of 5.5, at 30 °C, and at a NaCl concentration 3.7 mg/cm 3 (i.e., 145,165 ppm, which is 25.6 sft 3/ton).« less

Simultaneous selenate reduction and denitrification by a consortium of enriched mine site bacteria.

PubMed

Subedi, Gaurav; Taylor, Jon; Hatam, Ido; Baldwin, Susan A

2017-09-01

Increasing selenium concentrations in aquatic environments downstream of mine sites is of great concern due to selenium's bioaccumulation propensity and teratogenic toxicity. Removal of selenium from mine influenced water is complicated by the presence of nitrate, which is also elevated in mine influenced water due to the use of explosives in mining. In many biological treatment processes, nitrate as a thermodynamically more preferable electron acceptor inhibits selenate reduction. Here we report on an enrichment of a bacterial assemblage from a mine impacted natural marsh sediment that was capable of simultaneous selenate reduction and denitrification. Selenate reduction followed first order kinetics with respect to the concentration of total dissolved selenium. The kinetic rate constant was independent of initial nitrate concentration over the range 3-143 mg L -1 -NO 3 - -N. The initial concentration of selenate inhibited selenate reduction kinetics over the range 1-24 mg-Se L -1 . Dominant taxa that grew in selenate only medium were classified in the genera Pseudomonas, Lysinibacillus and Thauera. When nitrate was introduced in addition to selenate, previously rare taxa that became dominant were relatives of Exiguobacterium, Tissierella and Clostridium. Open reading frames (ORFs) associated with dissimilatory denitrification were identified for Pseudomonas, Thauera and Clostridium. In addition, ORFs were found that were homologous with known selenate reductase subunits (SerA and SerB). These findings suggest that native mine site bacteria can be used for removing selenate and nitrate from mine wastewater. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Vitamin blood concentration and vitamin supplementation in bottlenose dolphins (Tursiops truncatus) in European facilities.

PubMed

Gimmel, Angela Emilia Ricarda; Baumgartner, Katrin; Liesegang, Annette

2016-09-05

As fish eaters bottlenose dolphins (Tursiops truncatus) in human care need to receive daily vitamin supplementation, because whole thawed fish lacks certain vitamins. However, the exact concentration of supplementation has not been established and is a matter of discussion. To ensure adequate vitamin supplementation in pets, vitamin blood concentrations are measured. This is not a common practice in dolphins. The objective of the present study was to collect information about vitamin supplementation in bottlenose dolphins and on vitamin blood concentrations of healthy animals in European facilities. In addition, these results were compared with blood levels of wild animals. Conclusions on how to provide bottlenose dolphins in human care with an effective vitamin supplementation will then be drawn. Initially, fish-handling techniques and vitamin supplementation were evaluated by questionnaire, which was sent to 25 European facilities that house bottlenose dolphins. Secondly, blood samples from 57 dolphins living in 10 facilities were taken and sent by mail to a reference laboratory. They were analysed for retinol, thiamine pyrophosphate, cobalamin, calcidiol and tocopherol. The blood concentrations were then correlated with vitamin supplementation, fish handling techniques and pre-existing blood concentrations of free-ranging dolphins. Finally, the data was subjected to a standard analysis of variance techniques (ANOVA) and a linear model analysis. Fish was mainly thawed in a refrigerator. Further, the 95 % confidence interval for retinol blood concentrations was 0.048 to 0.059 mg/l and for tocopherol 17.95 to 20.76 mg/l. These concentrations were 27 and 53 %, respectively, higher than those found in free-ranging animals. In contrast, calcidiol concentrations (143.9-174.7 ng/ml) of the dolphins in human care were lower than in blood found for free-ranging animals. Regarding thiamine pyrophosphate and cobalamin, concentrations ranged between 0.42 and 0.55 mg/l and 175.55 and 275.22 pg/ml respectively. No reference concentrations for free-ranging Tursiops truncatus were found. These findings suggest an over-supplementation of retinol (vitamin A) and tocopherol (vitamin E) in bottlenose dolphins (Tursiops truncatus) housed in human care. Therefore, vitamin A supplementation should not exceed 50,000 IU per animal per day and vitamin E supplementation should be around 100 IU per kg fed fish per day.

A two-phase flow model for submarine granular flows: With an application to collapse of deeply-submerged granular columns

NASA Astrophysics Data System (ADS)

Lee, Cheng-Hsien; Huang, Zhenhua

2018-05-01

The collapse process of a submerged granular column is strongly affected by its initial packing. Previous models for particle response time, which is used to quantify the drag force between the solid and liquid phases in rheology-based two-phase flow models, have difficulty in simulating the collapse process of granular columns with different initial concentrations (initial packing conditions). This study introduces a new model for particle response time, which enables us to satisfactorily model the drag force between the two phases for a wide range of volume concentration. The present model can give satisfactory results for both loose and dense packing conditions. The numerical results have shown that (i) the initial packing affects the occurrence of contractancy/diltancy behavior during the collapse process, (ii) the general buoyancy and drag force are strongly affected by the initial packing through contractancy and diltancy, and (iii) the general buoyancy and drag force can destabilize the granular material in loose packing condition but stabilize the granular material in dense packing condition. The results have shown that the collapse process of a densely-packed granular column is more sensitive to particle response time than that of a loosely-packed granular column.

Influence of timing and dose of thyroid hormone replacement on mental, psychomotor, and behavioral development in children with congenital hypothyroidism.

PubMed

Bongers-Schokking, Jacoba J; de Muinck Keizer-Schrama, Sabine M P F

2005-12-01

To evaluate the influence of initial and postinitial treatment factors on cognitive, psychomotor, and psychological outcome in schoolchildren with congenital hypothyroidism (CH). We studied 45 patients (19 with severe CH and 26 with mild CH) and 37 control children by correlating initial and postinitial treatment factors (free thyroxine and thyroid-stimulating hormone [TSH] concentrations, and the percentage of overtreatment and undertreatment periods) with the results of neuropsychological tests and behavior (as reported on the Teacher Report Form [TRF]). The global IQ of the children with CH was comparable to that of the controls; visuomotor and verbal scores were lower, and total TRF scores were higher. Ethnic group, previous development, and overtreatment predicted IQ and verbal scores, with higher scores seen for the overtreated patients than for the control children and those patients who had not been overtreated. As initial treatment was less satisfactory, total TRF scores were higher. Our study suggests that initial and postinitial suboptimal treatment of CH leads to abnormalities in IQ and specific fields. Overtreatment may advance cognitive development in 5-1/2- to 7-year-olds. Suboptimal initial treatment may lead to behavioral problems. We recommend that TSH concentrations be maintained within the normal range in patients with CH.

Thyroid hormone concentrations in captive and free-ranging West Indian manatees (Trichechus manatus).

PubMed

Ortiz, R M; MacKenzie, D S; Worthy, G A

2000-12-01

Because thyroid hormones play a critical role in the regulation of metabolism, the low metabolic rates reported for manatees suggest that thyroid hormone concentrations in these animals may also be reduced. However, thyroid hormone concentrations have yet to be examined in manatees. The effects of captivity, diet and water salinity on plasma total triiodothyronine (tT(3)), total thyroxine (tT(4)) and free thyroxine (fT(4)) concentrations were assessed in adult West Indian manatees (Trichechus manatus). Free-ranging manatees exhibited significantly greater tT(4) and fT(4) concentrations than captive adults, regardless of diet, indicating that some aspect of a captive existence results in reduced T(4) concentrations. To determine whether this reduction might be related to feeding, captive adults fed on a mixed vegetable diet were switched to a strictly sea grass diet, resulting in decreased food consumption and a decrease in body mass. However, tT(4) and fT(4) concentrations were significantly elevated over initial values for 19 days. This may indicate that during periods of reduced food consumption manatees activate thyroid-hormone-promoted lipolysis to meet water and energetic requirements. Alterations in water salinity for captive animals did not induce significant changes in thyroid hormone concentrations. In spite of lower metabolic rates, thyroid hormone concentrations in captive manatees were comparable with those for other terrestrial and marine mammals, suggesting that the low metabolic rate in manatees is not attributable to reduced circulating thyroid hormone concentrations.

Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites.

PubMed

Ogunyinka, A; Palin, W M; Shortall, A C; Marquis, P M

2007-07-01

The effect of photoinitiator and co-initiator chemistry on the setting reaction and degree of conversion of dental resin-based composites (RBCs) has rarely been determined explicitly. This work examines the effect of type and concentration of photoinitiator and co-initiator on the rate of change of light transmission throughout polymerisation and degree of conversion of model RBC formulations. Bisphenol-A diglycidyl ether dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (6:4 molar ratio) resins filled with silanized glass filler (74wt.%) and containing various photoinitiators (camphorquinone; CQ, 1-phenyl-1,2-propanedione; PPD, benzil; BZ), co-initiator types (N,N-dimethyl-p-amino benzoic acid ethyl ester; DABE, N,N-cyanoethyl methylaniline; CEMA, N,N-diethanol-p-toluidine; DEPT) and concentration (0.0-0.3% DABE) were polymerised using a halogen or LED light curing-unit (LCU) for 10, 20 and 40s. The setting reaction was monitored in real-time by measuring the light transmittance through the curing specimen and bulk degree of conversion (DC) evaluated using Fourier transform infra-red spectroscopy. Specimens containing CQ and PPD cured with the halogen LCU did not have a significant effect on DC or changes in light transmission, although a significant increase in DC was observed for CQ compared with PPD specimens cured with the LED LCU. DABE and CEMA were more effective co-initiators than DEPT. Although DC was not limited by co-initiator concentration, the absence of a co-initiator resulted in marked differences in light transmission and decreased DC throughout 40s irradiation with each LCU type. The spectral range emitted from different types of LCU and absorption characteristics of the photoinitiator chemistry of light-activated resin-based composites play a critical role in the efficiency of polymerisation.

Factors affecting shear thickening behavior of a concentrated injectable suspension of levodopa.

PubMed

Allahham, Ayman; Stewart, Peter; Marriott, Jennifer; Mainwaring, David

2005-11-01

Previous clinical studies on a subcutaneous injectable suspension of levodopa showed poor injectability into human tissue. When this formulation was rheologically characterised, a clinical shear thickening interval was observed at increased shear rates. The formulation parameters that contributed to this rheological behavior were systematically evaluated with the aim of removing this flow limitation while maintaining the concentration of 60% levodopa to retain the clinical applicability. The three suspension parameters examined were: levodopa volume fraction, concentration of the HPMC suspending vehicle, and particle size distribution. Shear thickening increased with the drug concentration and the critical shear rate was inversely dependent on the drug concentration. Increasing the vehicle concentration retarded the shear thickening but increased the overall suspension viscosity. There was an increase in shear thickening with increased average particle diameter. Combinations of micronized and non-micronized particles were used to prepare bimodal particle size distributions. The rheology of these bimodal distributions resulted in removal of shear thickening. This allowed the preparation of 60% levodopa formulations that showed a range of flow characteristics spanning near Newtonian flow or shear thinning at initial injectable viscosities of about 0.6 Pa.s and final viscosities in the range of 0.1 Pa.s, alleviating the shear thickening limitation of these levodopa formulations.

Comparison of 4-chloro-2-nitrophenol adsorption on single-walled and multi-walled carbon nanotubes

PubMed Central

2012-01-01

The adsorption characteristics of 4-chloro-2-nitrophenol (4C2NP) onto single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) from aqueous solution were investigated with respect to the changes in the contact time, pH of solution, carbon nanotubes dosage and initial 4C2NP concentration. Experimental results showed that the adsorption efficiency of 4C2NP by carbon nanotubes (both of SWCNTs and MWCNTs) increased with increasing the initial 4C2NP concentration. The maximum adsorption took place in the pH range of 2–6. The linear correlation coefficients of different isotherm models were obtained. Results revealed that the Langmuir isotherm fitted the experimental data better than the others and based on the Langmuir model equation, maximum adsorption capacity of 4C2NP onto SWCNTs and MWCNTs were 1.44 and 4.42 mg/g, respectively. The observed changes in the standard Gibbs free energy, standard enthalpy and standard entropy showed that the adsorption of 4C2NP onto SWCNTs and MWCNTs is spontaneous and exothermic in the temperature range of 298–328 K. PMID:23369489

Kinetics and Thermodynamics of Reserpine Adsorption onto Strong Acidic Cationic Exchange Fiber

PubMed Central

Guo, Zhanjing; Liu, Xiongmin; Huang, Hongmiao

2015-01-01

The kinetics and thermodynamics of the adsorption process of reserpine adsorbed onto the strong acidic cationic exchange fiber (SACEF) were studied by batch adsorption experiments. The adsorption capacity strongly depended on pH values, and the optimum reserpine adsorption onto the SACEF occurred at pH = 5 of reserpine solution. With the increase of temperature and initial concentration, the adsorption capacity increased. The equilibrium was attained within 20 mins. The adsorption process could be better described by the pseudo-second-order model and the Freundlich isotherm model. The calculated activation energy Ea was 4.35 kJ/mol. And the thermodynamic parameters were: 4.97<ΔH<7.44 kJ/mol, -15.29<ΔG<-11.87 kJ/mol and 41.97<ΔS<47.35 J/mol·K. The thermodynamic parameters demonstrated that the adsorption was an endothermic, spontaneous and feasible process of physisorption within the temperature range between 283 K and 323 K and the initial concentration range between 100 mg/L and 300 mg/L. All the results showed that the SACEF had a good adsorption performance for the adsorption of reserpine from alcoholic solution. PMID:26422265

Photo-catalytic decolourisation of toxic dye with N-doped titania: a case study with Acid Blue 25.

PubMed

Chakrabortty, Dhruba; Gupta, Susmita Sen

2013-05-01

Dyes are one of the hazardous water pollutants. Toxic Acid Blue 25, an anthraquinonic dye, has been decolourised by photo-catalysing it with nitrogen doped titania in aqueous medium. The photo catalyst was prepared from 15% TiCl3 and 25% aqueous NH3 solution as precursor. XRD and TEM revealed the formation of well crystalline anatase phase having particle size in the nano-range. BET surface area of the sample was higher than that of pure anatase TiO2. DRS showed higher absorption of radiation in visible range compared to pure anatase TiO2. XPS revealed the presence of nitrogen in N-Ti-O environment. The experimental parameters, namely, photocatalyst dose, initial dye concentration as well as solution pH influence the decolourisation process. At pH 3.0, the N-TiO2 could decolourise almost 100% Acid Blue 25 within one hour. The influence of N-TiO2 dose, initial concentration of Acid Blue 25 and solution pH on adsorption-desorption equilibrium is also studied. The adsorption process follows Lagergren first order kinetics while the modified Langmuir-Hinselwood model is suitably fitted for photocatalytic decolourisation of Acid Blue 25.

Evidence for presence of nonesterified fatty acids as potential gustatory signaling molecules in humans.

PubMed

Kulkarni, Bhushan; Mattes, Richard

2013-02-01

Gustatory fatty acid signaling termed "fatty acid taste" is initiated when nonesterified fatty acids (NEFA) bind to putative fat receptors on taste receptor cells. However, the source and quantity of NEFA in the oral cavity of humans are unresolved. Dietary fat is comprised predominantly of triacylglycerol, and human lingual lipase is of questionable functionality. The objective of this study was to characterize the species of NEFA in saliva and quantify their individual concentrations during oral processing of high-fat foods. Participants chewed fixed amounts of almonds, coconut, walnuts, almond butter, and olive oil (stimuli that vary in physical state and fatty acid composition) for 1 min at the rate of 1 bite/s and expectorated. The salivary NEFA from the expectorant were quantitatively and qualitatively analyzed by gas chromatography-mass spectrometry. Palmitic, oleic, linoleic, and stearic acids were the 4 predominant salivary NEFA, reflecting their concentrations in the foods tested. Their significantly increased concentrations ranged from 20 to 60 µM. Previous animal electrophysiological studies suggest that these NEFA concentrations are sufficient to depolarize taste receptor cells. These data indicate NEFA concentrations likely to be sufficient to initiate gustatory signaling are present in the human oral cavity when masticating high-fat foods.

Primaquine in Plasma and Methemoglobinemia in Patients with Malaria Due to Plasmodium vivax in the Brazilian Amazon Basin.

PubMed

Vieira, José Luiz; Ferreira, Michelle E S; Ferreira, Michelle V D; Gomes, Margarete M

2017-05-01

AbstractPrimaquine is the only licensed drug available for the elimination of Plasmodium vivax hypnozoites. Methemoglobinemia is currently reported in the course of treatment. There is evidence that metabolites of primaquine formed by the cytochrome pathway are responsible for methemoglobin formation; a genetic polymorphism of cytochrome isoforms; and a potential influence of gender in the activities of these enzymes requiring the establishment of dose × response curves profiles in different population groups. Concentrations of primaquine in plasma and methemoglobin levels were investigated in 54 patients with malaria due to P. vivax during the course of the standard regimen of chloroquine with primaquine (0.25 mg/kg/day for 14 days). All study subjects lived in an endemic area of the Brazilian Amazon Basin. The blood samples were collected before initiation of treatment and 3 hours (range 2-4 hours) after the administration of antimalarial drugs on days 2, 7, and 14. Plasma primaquine concentrations were similar in both genders (males: range = 164-191 ng/mL, females: range = 193-212 ng/mL). Methemoglobin levels ranged from 3.3% to 5.9% in males and from 3.1% to 6.5% in females. There were no significant correlations between the plasma primaquine concentrations or total dose and methemoglobin levels, suggesting that unidentified metabolites rather than parent drug were likely responsible for changes in methemoglobin levels. There was no significant influence of gender on primaquine concentrations in plasma or methemoglobin levels.

Specific Conductance and Dissolved-Solids Characteristics for the Green River and Muddy Creek, Wyoming, Water Years 1999-2008

USGS Publications Warehouse

Clark, Melanie L.; Davidson, Seth L.

2009-01-01

Southwestern Wyoming is an area of diverse scenery, wildlife, and natural resources that is actively undergoing energy development. The U.S. Department of the Interior's Wyoming Landscape Conservation Initiative is a long-term science-based effort to assess and enhance aquatic and terrestrial habitats at a landscape scale, while facilitating responsible energy development through local collaboration and partnerships. Water-quality monitoring has been conducted by the U.S. Geological Survey on the Green River near Green River, Wyoming, and Muddy Creek near Baggs, Wyoming. This monitoring, which is being conducted in cooperation with State and other Federal agencies and as part of the Wyoming Landscape Conservation Initiative, is in response to concerns about potentially increased dissolved solids in the Colorado River Basin as a result of energy development. Because of the need to provide real-time dissolved-solids concentrations for the Green River and Muddy Creek on the World Wide Web, the U.S. Geological Survey developed regression equations to estimate dissolved-solids concentrations on the basis of continuous specific conductance using relations between measured specific conductance and dissolved-solids concentrations. Specific conductance and dissolved-solids concentrations were less varied and generally lower for the Green River than for Muddy Creek. The median dissolved-solids concentration for the site on the Green River was 318 milligrams per liter, and the median concentration for the site on Muddy Creek was 943 milligrams per liter. Dissolved-solids concentrations ranged from 187 to 594 milligrams per liter in samples collected from the Green River during water years 1999-2008. Dissolved-solids concentrations ranged from 293 to 2,485 milligrams per liter in samples collected from Muddy Creek during water years 2006-08. The differences in dissolved-solids concentrations in samples collected from the Green River compared to samples collected from Muddy Creek reflect the different basin characteristics. Relations between specific conductance and dissolved-solids concentrations were statistically significant for the Green River (p-value less than 0.001) and Muddy Creek (p-value less than 0.001); therefore, specific conductance can be used to estimate dissolved-solids concentrations. Using continuous specific conductance values to estimate dissolved solids in real-time on the World Wide Web increases the amount and improves the timeliness of data available to water managers for assessing dissolved-solids concentrations in the Colorado River Basin.

Model predictions of realgar precipitation by reaction of As(III) with synthetic mackinawite under anoxic conditions

USGS Publications Warehouse

Gallegos, T.J.; Han, Y.-S.; Hayes, K.F.

2008-01-01

This study investigates the removal of As(III) from solution using mackinawite, a nanoparticulate reduced iron sulfide. Mackinawite suspensions (0.1-40 g/L) effectively lower initial concentrations of 1.3 ?? 10 -5 M As(III) from pH 5-10, with maximum removal occurring under acidic conditions. Based on Eh measurements, it was found that the redox state of the system depended on the mackinawite solids concentration and pH. Higher initial mackinawite concentrations and alkaline pH resulted in a more reducing redox condition. Given this, the pH edge data were modeled thermodynamically using pe (-log[e-]) as a fitting parameter and linear pe-pH relationships within the range of measured Eh values as a function of pH and mackinawite concentration. The model predicts removal of As(III) from solution by precipitation of realgar with the formation of secondary oxidation products, greigite or a mixed-valence iron oxide phase, depending on pH. This study demonstrates that mackinawite is an effective sequestration agent for As(III) and highlights the importance of incorporating redox into models describing the As-Fe-S-H2O system. ?? 2008 American Chemical Society.

Remediation of lead-contaminated soils

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

Peters, R.W.; Shem, L.

1992-01-01

Excavation and transport of soil contaminated with heavy metals has generally been the standard remediation technique for treatment of heavy-metal-contaminated soils. This approach is not a permanent solution; moreover, off-site shipment and disposal of contaminated soil involves high expense, liability, and appropriate regulatory approval. Recently, a number of other techniques have been investigated for treating such contaminated sites, including flotation, solidification/stabilization, vitrification, and chemical extraction. This paper reports the results of a laboratory investigation determining the efficiency of using chelating agents to extract lead from contaminated soils. Lead concentrations in the soils ranged from 500 to 10,000 mg/kg. Ethylenediaminetetraacetic acidmore » (EDTA) and nitrilotriacetic acid (NTA) were examined for their potential extractive capabilities. Concentrations of the chelating agents ranged from 0.01 to 0.10 M. The pH of the suspensions in which the extractions were performed ranged from 4 to 12. Results showed that the removal of lead using NTA and water was ph-dependent, whereas the removal of lead using EDTA was ph-insensitive. Maximum removals of lead were 68.7%,19.1%, and 7.3% using EDTA, NTA, and water, respectively (as compared with initial lead concentrations).« less

Remediation of lead-contaminated soils

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

Peters, R.W.; Shem, L.

1992-09-01

Excavation and transport of soil contaminated with heavy metals has generally been the standard remediation technique for treatment of heavy-metal-contaminated soils. This approach is not a permanent solution; moreover, off-site shipment and disposal of contaminated soil involves high expense, liability, and appropriate regulatory approval. Recently, a number of other techniques have been investigated for treating such contaminated sites, including flotation, solidification/stabilization, vitrification, and chemical extraction. This paper reports the results of a laboratory investigation determining the efficiency of using chelating agents to extract lead from contaminated soils. Lead concentrations in the soils ranged from 500 to 10,000 mg/kg. Ethylenediaminetetraacetic acidmore » (EDTA) and nitrilotriacetic acid (NTA) were examined for their potential extractive capabilities. Concentrations of the chelating agents ranged from 0.01 to 0.10 M. The pH of the suspensions in which the extractions were performed ranged from 4 to 12. Results showed that the removal of lead using NTA and water was ph-dependent, whereas the removal of lead using EDTA was ph-insensitive. Maximum removals of lead were 68.7%,19.1%, and 7.3% using EDTA, NTA, and water, respectively (as compared with initial lead concentrations).« less

Detonability of H/sub 2/-air-diluent mixtures

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

Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.

1987-06-01

This report describes the Heated Detonation Tube (HDT). Detonation cell width and velocity results are presented for H/sub 2/-air mixtures, undiluted and diluted with CO/sub 2/ and H/sub 2/O for a range of H/sub 2/ concentration, initial temperature and pressure. The results show that the addition of either CO/sub 2/ or H/sub 2/O significantly increases the detonation cell width and hence reduces the detonability of the mixture. The results also show that the detonation cell width is reduced (detonability is increased) for increased initial temperature and/or pressure.

Comparison of measured ozone in southeastern Virginia with computer predictions from a photochemical model

NASA Technical Reports Server (NTRS)

Wakelyn, N. T.; Gregory, G. L.

1980-01-01

Data for one day of the 1977 southeastern Virginia urban plume study are compared with computer predictions from a traveling air parcel model using a contemporary photochemical mechanism with a minimal description of nonmethane hydrocarbon (NMHC) constitution and chemistry. With measured initial NOx and O3 concentrations and a current separate estimate of urban source loading input to the model, and for a variation of initial NMHC over a reasonable range, an ozone increase over the day is predicted from the photochemical simulation which is consistent with the flight path averaged airborne data.

Novel kinetic spectrophotometric method for estimation of certain biologically active phenolic sympathomimetic drugs in their bulk powders and different pharmaceutical formulations

NASA Astrophysics Data System (ADS)

Omar, Mahmoud A.; Badr El-Din, Khalid M.; Salem, Hesham; Abdelmageed, Osama H.

2018-03-01

A simple, selective and sensitive kinetic spectrophotometric method was described for estimation of four phenolic sympathomimetic drugs namely; terbutaline sulfate, fenoterol hydrobromide, isoxsuprine hydrochloride and etilefrine hydrochloride. This method is depended on the oxidation of the phenolic drugs with Folin-Ciocalteu reagent in presence of sodium carbonate. The rate of color development at 747-760 nm was measured spectrophotometrically. The experimental parameters controlling the color development were fully studied and optimized. The reaction mechanism for color development was proposed. The calibration graphs for both the initial rate and fixed time methods were constructed, where linear correlations were found in the general concentration ranges of 3.65 × 10- 6-2.19 × 10- 5 mol L- 1 and 2-24.0 μg mL- 1 with correlation coefficients in the following range 0.9992-0.9999, 0.9991-0.9998 respectively. The limits of detection and quantitation for the initial rate and fixed time methods were found to be in general concentration range 0.109-0.273, 0.363-0.910 and 0.210-0.483, 0.700-1.611 μg mL- 1 respectively. The developed method was validated according to ICH and USP 30 -NF 25 guidelines. The suggested method was successfully implemented to the estimation of these drugs in their commercial pharmaceutical formulations and the recovery percentages obtained were ranged from 97.63% ± 1.37 to 100.17% ± 0.95 and 97.29% ± 0.74 to 100.14 ± 0.81 for initial rate and fixed time methods respectively. The data obtained from the analysis of dosage forms were compared with those obtained by reported methods. Statistical analysis of these results indicated no significant variation in the accuracy and precision of both the proposed and reported methods.

Influence of reabsorption and reemission on stimulated Raman scattering of polymethine dyes in multiple scattering media

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

Yashchuk, V P; Komyshan, A O; Smaliuk, A P

2013-12-31

It is shown that reabsorption of the luminescence radiation in the range of its overlapping with the absorption spectrum and the following reemission to a long-wavelength range may noticeably affect the process of stimulated Raman scattering (SRS) in polymethine dyes in multiple scattering media (MSM). This is related to the fact that SRS in such media occurs jointly with the random lasing (RL), which favors SRS and makes up with it a united nonlinear process. Reemission into the long-wavelength spectrum range amplified in MSM causes the RL spectrum to shift to longer wavelengths and initiates the long-wavelength band of RL,more » in which a main part of the lasing energy is concentrated. This weakens or completely stops the SRS if the band is beyond the range of possible spectral localisation of Stokes lines. This process depends on the efficiency of light scattering, dye concentration, temperature and pump intensity; hence, there exist optimal values of these parameters for obtaining SRS in MSM. (nonlinear optical phenomena)« less

Nutrient removal and lipid production by Coelastrella sp. in anaerobically and aerobically treated swine wastewater.

PubMed

Luo, Le; He, Huijun; Yang, Chunping; Wen, Shan; Zeng, Guangming; Wu, Mengjie; Zhou, Zili; Lou, Wei

2016-09-01

Coelastrella sp. QY01, a microalgae species isolated from a local pond, was identified and used for the treatment of anaerobically and aerobically treated swine wastewater (AnATSW). Microalgal growth characteristics, nutrient removal and lipid accumulation of QY01 cultivated in the initial concentration of AnATSW ranged from 63 to 319mg NH3-N/L were examined. The specific growth rate of QY01 cultivated in cultures ranged from 0.269 to 0.325day(-1) with a biomass productivity from 42.77 to 57.46mgL(-1)day(-1). Removal rates for NH3-N, TP and inorganic carbon in AnATSW at the various nutrient concentrations ranged from 90% to 100%, from 90% to 100% and from 74% to 78%, respectively. The lipid content of QY01 ranged from 22.4% to 24.8%. The lipid productivity was positive correlation with the biomass productivity. 40% AnATSW was optimal for QY01 cultivation, in which nutrient removal and productivity of biomass and lipid were maximized. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of a commercial glyphosate formulation on adsorption of Cd(II) and Pb(II) ions on paddy soil.

PubMed

Divisekara, T; Navaratne, A N; Abeysekara, A S K

2018-05-01

Use of glyphosate as a weedicide on rice cultivation has been a controversial issue in Sri Lanka, due to the hypothesis that the metal complexes of commercial glyphosate is one of the causative factors of Chronic Kidney Disease of unknown aetiology (CKDu) prevalent in some parts of Sri Lanka. The effect of commercial glyphosate on the adsorption and desorption of Cd(II) and Pb(II) ions on selective paddy soil studied using batch experiments, over a wide concentration range, indicates that the Langmuir adsorption isotherm model is obeyed at low initial metal ion concentrations while the Freundlich adsorption isotherm model obeys at high metal ion concentrations in the presence and absence of glyphosate. For all cases, adsorption of both Cd(II) and Pb(II) ions obeys pseudo second order kinetics, suggesting that initial adsorption is a chemisorption process. In the presence of glyphosate formulation, the extent of adsorption of Cd(II) and Pb(II) ions on soil is decreased, while their desorption is increased at high concentrations of glyphosate. Low concentrations of glyphosate formulation do not significantly affect the desorption of metal ions from soil. Reduction of adsorption leads to enhance the concentration of Cd(II) and Pb(II) ions in the aqueous phase when in contact with soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biodegradation of PAHs in Soil: Influence of Initial PAHs Concentration

NASA Astrophysics Data System (ADS)

Kamil, N. A. F. M.; Talib, S. A.

2016-07-01

Most studies on biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) evaluate the effect of initial PAHs concentration in liquid medium. There are limited studies on evaluation in solid medium such as contaminated soil. This study investigated the potential of the bacteria, Corynebacterium urealyticum isolated from municipal sludge in degrading phenanthrene contaminated soil in different phenanthrene concentration. Batch experiments were conducted over 20 days in reactors containing artificially contaminated phenanthrene soil at different concentration inoculated with a bacterial culture. This study established the optimum condition for phenanthrene degradation by the bacteria under nonindigenous condition at 500 mg/kg of initial phenanthrene concentration. High initial concentration required longer duration for biodegradation process compared to low initial concentration. The bacteria can survive for three days for all initial phenanthrene concentrations.

Optimization of NO oxidation by H2O2 thermal decomposition at moderate temperatures.

PubMed

Zhao, Hai-Qian; Wang, Zhong-Hua; Gao, Xing-Cun; Liu, Cheng-Hao; Qi, Han-Bing

2018-01-01

H2O2 was adopted to oxidize NO in simulated flue gas at 100-500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300-500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.

Optimization of NO oxidation by H2O2 thermal decomposition at moderate temperatures

PubMed Central

Wang, Zhong-hua; Gao, Xing-cun; Liu, Cheng-hao; Qi, Han-bing

2018-01-01

H2O2 was adopted to oxidize NO in simulated flue gas at 100–500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300–500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption. PMID:29668672

Occurrence and effects of tire wear particles in the environment--a critical review and an initial risk assessment.

PubMed

Wik, Anna; Dave, Göran

2009-01-01

This review summarizes the existing knowledge on the occurrence of tire wear particles in the environment, and their ecotoxicological effects. A meta-analysis on tire components in the environment revealed that tire wear particles are present in all environmental compartments, including air, water, soils/sediments, and biota. The maximum Predicted Environmental Concentrations (PECs) of tire wear particles in surface waters range from 0.03 to 56 mg l(-1) and the maximum PECs in sediments range from 0.3 to 155 g kg(-1) d.w. The results from our previous long-term studies with Ceriodaphnia dubia and Pseudokirchneriella subcapitata were used to derive Predicted No Effect Concentrations (PNECs). The upper ranges for PEC/PNEC ratios in water and sediment were >1, meaning that tire wear particles present potential risks for aquatic organisms. We suggest that management should be directed towards development and production of more environmentally friendly tires and improved road runoff treatment.

Response of the Mimeae to some Physical and Chemical Agents1

PubMed Central

Snodgrass, Charlotte J.; Koburger, J. A.

1968-01-01

Isolates of Mima polymorpha and Herellea vaginicola obtained from retail food products were investigated for their ability to hydrolyze proteins, starch, and lipids as well as for their ability to initiate growth under varying conditions of pH, sodium chloride concentration, and temperature. None of the isolates hydrolyzed starch and a few hydrolyzed proteins, whereas most were actively lipolytic. Members of each genus grew over the range 6 to 42 C; in general, H. vaginicola was more tolerant to high concentrations of sodium chloride and to acid conditions than was M. polymorpha. PMID:5726150

Effect of racing on the serum concentrations of cardiac troponin I and creatine kinase myocardial band in racing camels (Camelus dromedarius).

PubMed

Tharwat, Mohamed; Al-Sobayil, Fahd; Buczinski, Sébastien

2013-06-01

This study was designed to investigate the effect of racing on the serum concentrations of cardiac troponin I (cTnI) and creatine kinase myocardial (CK-MB) in healthy racing camels (Camelus dromedarius). Twenty-three racing camels scheduled for a 5 km race were investigated in this study. From each camel, 3 blood samples were collected: 24 h before racing (T0), within 2 h after the race (T1) and 24 h post-race (T2). Following the 5 km race, 91.3 % of the racing camels had increases in serum cTnI concentrations, while concentrations remained unchanged in 8.7 %. The cTnI concentration (median 0.06 ng/mL; range, 0.03-0.15 ng/mL) was significantly higher (P < 0.001) than the pre-race values (median 0.04 ng/mL; range, 0.01-0.07 ng/mL). Twenty-four hours post-race, the cTnI concentrations had returned very nearly to their pre-race values (median 0.04 ng/mL; range, 0.00-0.09 ng/mL) and were not significantly different (P = 0.35) from the pre-race values. Following the 5 km race, increases in CK-MB mass were seen in 17.4 % of the camels, with no changes in 4.3 % and decreases in 78.3 %. The CK-MB mass (median 0.41 ng/mL; range, 0.19-0.60 ng/mL) did not differ significantly (P = 0.84) when compared to the pre-race values (median 0.42 ng/mL; range, 0.32-0.55 ng/mL). Twenty-four hours post-race, the CK-MB mass concentrations (median 0.41 ng/mL; range, 0.15-0.55 ng/mL) did not differ significantly (P > 0.05) compared to pre-race or immediate post-race values. Resting cTnI concentrations in the racing camels were initially low, but increased above the baseline level in most of the camels immediately after racing, and returned to pre-race values within the 24-h post-race period. CK-MB is a less sensitive biomarker for myocardial activity as compared with cTnI. These findings could be of importance when evaluating racing camels with suspected cardiac disease after recent hard exercise.

Quantum cascade laser photoacoustic detection of nitrous oxide released from soils for biofuel production

NASA Astrophysics Data System (ADS)

Couto, F. M.; Sthel, M. S.; Castro, M. P. P.; da Silva, M. G.; Rocha, M. V.; Tavares, J. R.; Veiga, C. F. M.; Vargas, H.

2014-12-01

In order to investigate the generation of greenhouse gases in sugarcane ethanol production chain, a comparative study of N2O emission in artificially fertilized soils and soils free from fertilizers was carried out. Photoacoustic spectroscopy using quantum cascade laser with an emission ranging from 7.71 to 7.88 µm and differential photoacoustic cell were applied to detect nitrous oxide (N2O), an important greenhouse gas emitted from soils cultivated with sugar cane. Owing to calibrate the experimental setup, an initial N2O concentration was diluted with pure nitrogen and detection limit of 50 ppbv was achieved. The proposed methodology was selective and sensitive enough to detect N2O from no fertilized and artificially fertilized soils. The measured N2O concentration ranged from ppmv to ppbv.

Dynamical patterns and regime shifts in the nonlinear model of soil microorganisms growth

NASA Astrophysics Data System (ADS)

Zaitseva, Maria; Vladimirov, Artem; Winter, Anna-Marie; Vasilyeva, Nadezda

2017-04-01

Dynamical model of soil microorganisms growth and turnover is formulated as a system of nonlinear partial differential equations of reaction-diffusion type. We consider spatial distributions of concentrations of several substrates and microorganisms. Biochemical reactions are modelled by chemical kinetic equations. Transport is modelled by simple linear diffusion for all chemical substances, while for microorganisms we use different transport functions, e.g. some of them can actively move along gradient of substrate concentration, while others cannot move. We solve our model in two dimensions, starting from uniform state with small initial perturbations for various parameters and find parameter range, where small initial perturbations grow and evolve. We search for bifurcation points and critical regime shifts in our model and analyze time-space profile and phase portraits of these solutions approaching critical regime shifts in the system, exploring possibility to detect such shifts in advance. This work is supported by NordForsk, project #81513.

Application of Fenton oxidation to cosmetic wastewaters treatment.

PubMed

Bautista, P; Mohedano, A F; Gilarranz, M A; Casas, J A; Rodriguez, J J

2007-05-08

The removal of organic matter (TOC and COD) from a cosmetic wastewater by Fenton oxidation treatment has been evaluated. The operating conditions (temperature as well as ferrous ion and hydrogen peroxide dosage) have been optimized. Working at an initial pH equal to 3.0, a Fe(2+) concentration of 200 mg/L and a H(2)O(2) concentration to COD initial weight ratio corresponding to the theoretical stoichiometric value (2.12), a TOC conversion higher than 45% at 25 degrees C and 60% at 50 degrees C was achieved. Application of the Fenton oxidation process allows to reach the COD regional limit for industrial wastewaters discharges to the municipal sewer system. A simple kinetic analysis based on TOC was carried out. A second-order equation describes well the overall kinetics of the process within a wide TOC conversion range covering up to the 80-90% of the maximum achievable conversion.

Northern peatland initiation lagged abrupt increases in deglacial atmospheric CH4

PubMed Central

Reyes, Alberto V.; Cooke, Colin A.

2011-01-01

Peatlands are a key component of the global carbon cycle. Chronologies of peatland initiation are typically based on compiled basal peat radiocarbon (14C) dates and frequency histograms of binned calibrated age ranges. However, such compilations are problematic because poor quality 14C dates are commonly included and because frequency histograms of binned age ranges introduce chronological artefacts that bias the record of peatland initiation. Using a published compilation of 274 basal 14C dates from Alaska as a case study, we show that nearly half the 14C dates are inappropriate for reconstructing peatland initiation, and that the temporal structure of peatland initiation is sensitive to sampling biases and treatment of calibrated 14C dates. We present revised chronologies of peatland initiation for Alaska and the circumpolar Arctic based on summed probability distributions of calibrated 14C dates. These revised chronologies reveal that northern peatland initiation lagged abrupt increases in atmospheric CH4 concentration at the start of the Bølling–Allerød interstadial (Termination 1A) and the end of the Younger Dryas chronozone (Termination 1B), suggesting that northern peatlands were not the primary drivers of the rapid increases in atmospheric CH4. Our results demonstrate that subtle methodological changes in the synthesis of basal 14C ages lead to substantially different interpretations of temporal trends in peatland initiation, with direct implications for the role of peatlands in the global carbon cycle. PMID:21368146

Acute salicylate poisoning: risk factors for severe outcome.

PubMed

Shively, Rachel M; Hoffman, Robert S; Manini, Alex F

2017-03-01

Salicylate poisoning remains a significant public health threat with more than 20,000 exposures reported annually in the United States. We aimed to establish early predictors of severe in-hospital outcomes in Emergency Department patients presenting with acute salicylate poisoning. This was a secondary data analysis of adult salicylate overdoses from a prospective cohort study of acute drug overdoses at two urban university teaching hospitals from 2009 to 2013. Patients were included based on confirmed salicylate ingestion and enrolled consecutively. Demographics, clinical parameters, treatment and disposition were collected from the medical record. Severe outcome was defined as a composite occurrence of acidemia (pH <7.3 or bicarbonate <16 mEq/L), hemodialysis, and/or death. Out of 1997 overdoses screened, 48 patients met inclusion/exclusion criteria. Patient characteristics were 43.8% male, median age 32 (range 18-87), mean initial salicylate concentration 28.1 mg/dL (SD 26.6), and 20.8% classified as severe outcome. Univariate analysis indicated that age, respiratory rate, lactate, coma, and the presence of co-ingestions were significantly associated with severe outcome, while initial salicylate concentration alone had no association. However, when adjusted for salicylate concentration, only age (OR 1.13; 95% CI 1.02-1.26) and respiratory rate (OR 1.29; 95% CI 1.02-1.63) were independent predictors. Additionally, lactate showed excellent test characteristics to predict severe outcome, with an optimal cutpoint of 2.25 mmol/L (78% sensitivity, 67% specificity). In adult Emergency Department patients with acute salicylate poisoning, independent predictors of severe outcome were older age and increased respiratory rate, as well as initial serum lactate, while initial salicylate concentration alone was not predictive.

Tuning the electrocaloric effect by varying Sr concentration in ferroelectric Ba1 -xSrxTiO3

NASA Astrophysics Data System (ADS)

Lisenkov, S.; Ponomareva, I.

2018-05-01

The electrocaloric effect is investigated systematically in Ba1 -xSrxTiO3 ferroelectrics using a semiclassical direct computational approach. The data are reported for the technologically important range of Sr concentrations of 0.0-0.6, electric fields up to 1000 kV/cm, and temperatures ranging from 5 to 600 K. A detailed comparison of computational data with experimental data from the literature reveals semiquantitative agreement and suggests the origin of discrepancies. The electrocaloric change in temperature Δ T shows strong dependence on Sr concentration which offers a way to tune electrocaloric response. In particular, the maximum electrocaloric Δ T is found to decrease with the increase in Sr concentration, whereas the location of the maximum shifts towards lower temperatures following the Curie point of the ferroelectric. Surprisingly, the width of the peak in the dependence of Δ T on the initial temperature is independent of the Sr concentration but shows a strong dependence on the applied electric field. Computational data are used to propose a compositionally graded ferroelectric Ba0.70Sr0.30TiO3/Ba0.55Sr0.45TiO3/Ba0.50Sr0.50TiO3/Ba0.45Sr0.55TiO3 whose Δ T shows almost no temperature dependence in the technologically important range of temperatures and electric fields. Such a desirable feature could potentially lead to the enhancement of relative cooling power.

Microbial community dynamics and methane, carbon dioxide, oxygen, and nitrous oxide concentrations in upland forest and riparian soils across a seasonal gradient of fully saturated soils to completely dried soils

NASA Astrophysics Data System (ADS)

Jones, R. T.; McGlynn, B. L.; McDermott, T.; Dore, J. E.

2015-12-01

Gas concentrations (CH4, CO2, N2O, and O2), soil properties (soil water content and pH), and microbial community composition were measured from soils at 32 sites across the Stringer Creek Watershed in the Tenderfoot Creek Experimental Forest 7 times between June 3, 2013 and September 20, 2013. Soils were fully saturated during the initial sampling period and dried down over the course of the summer. Soils and gas were sampled from 5cm and 20cm at each site and also at 50cm at eight riparian sites. In total, 496 individual soil samples were collected. Soil moisture ranged from 3.7% to fully saturated; soil pH ranged from 3.60 to 6.68. Methane concentrations in soils ranged from 0.426 ppm to 218 ppm; Carbon dioxide concentrations ranged from 550 ppm to 42,990 ppm; Nitrous oxide concentrations ranged from 0.220 ppm to 2.111 ppm; Oxygen concentrations ranged from 10.2% to 21.5%. Soil microbial communities were characterized by DNA sequences covering the V4 region of the 16S rRNA gene. DNA sequences were generated (~30,000,000 sequences) from the 496 soil samples using the Illumina MiSeq platform. Operational Taxonomic Units were generated using USEARCH, and representative sequences were taxonomically classified according the Ribosomal Database Project's taxonomy scheme. Analysis of similarity revealed that microbial communities found within a landscape type (high upland forest, low upland forest, riparian) were more similar than among landscape types (R = 0.600; p<0.001). Similarly, communities from unique site x depths were similar across the 7 collection periods (R = 0.646; p<0.001) despite changes in soil moisture. Euclidean distances of soil properties and gas concentrations were compared to Bray-Curtis community dissimilarity matrices using Mantel tests to determine how community structure co-varies with the soil environment and gas concentrations. All variables measured significantly co-varied with microbial community membership (pH: R = 0.712, p < 0.001; CO2: R = 0.578, p < 0.001; O2: R = 0.517, p < 0.001; Soil moisture: R = 0.408, p < 0.001; N2O: R = 0.218, p = 0.003; CH4: R = 0.195, p = 0.008). Despite the rather low co-variation between methane concentrations and microbial community composition, relative abundances of methanotrophic and methanogenic lineages did co-vary strongly with methane concentrations.

Evaluation of Emerging Contaminants of Concern at the South District Wastewater Treatment Plant Based on Seasonal Events, Miami-Dade County, Florida, 2004

USGS Publications Warehouse

Lietz, Arthur C.; Meyer, Michael T.

2006-01-01

The Comprehensive Everglades Restoration Plan has identified highly treated wastewater as a possible water source for the restoration of natural water flows and hydroperiods in selected coastal areas, including the Biscayne Bay coastal wetlands. One potential source of reclaimed wastewater for the Biscayne Bay coastal wetlands is the effluent from the South District Wastewater Treatment Plant in southern Miami-Dade County. The U.S. Geological Survey, in cooperation with the Comprehensive Everglades Restoration Plan Wastewater Reuse Technology Pilot Project Delivery Team, initiated a study to assess the presence of emerging contaminants of concern in the South District Wastewater Treatment Plant influent and effluent using current wastewater-treatment methods. As part of the study, 24-hour composite and discrete samples were collected at six locations (influent at plants 1 and 2, effluent pump, reuse train, chlorine dioxide unit, and ultraviolet pilot unit) at the plant during: (1) a dry-season, low-flow event on March 2-3, 2004, with an average inflow rate of 83.7 million gallons per day; (2) a wet-season, average-flow event on July 20-21, 2004, with an average inflow rate of 89.7 million gallons per day; and (3) high-rate disinfection tests on October 5 and 20, 2004, with average flow rates of 84.1 and 119.6 million gallons per day, respectively. During these four sampling events, 26, 27, 29, and 35 constituents were detected, respectively. The following transformations in concentration were determined in the waste stream: -100 to 180 percent at the effluent pump and -100 to 85 percent at the reuse train on March 2-3, 2004, and -100 to 1,609 percent at the effluent pump and -100 to 832 percent at the reuse train on July 20-21, 2004; -100 to -37 percent at the effluent pump, -100 to -62 percent at the reuse train, -100 to -56 percent at the chlorine dioxide unit, and -100 to -40 percent at the ultraviolet pilot unit on October 5, 2004; and -100 to -4 percent at the effluent pump, -100 to 17 percent at the reuse train, -100 to -40 percent at the chlorine dioxide unit, and -100 to -14 percent at the ultraviolet pilot unit on October 20, 2004. Samples were tested for detection of household and industrial (organic) wastewater compounds, pharmaceutical compounds, antibiotic compounds, and hormones in influent. Two 'known' endocrine disrupting compounds?17 beta-estradiol (E2) and diethoxynonylphenol? and four 'suspected' endocrine-disrupting compounds?1,4-dichlorobenzene, benzophenone, tris(2-chloroethyl) phosphate, and tris(dichloroisopropyl) phosphate?were detected during these sampling events. Phenanthrene and indole showed the greatest concentration ranges and highest concentrations for the organic wastewater compounds. Acetaminophen showed the greatest concentration range and highest concentration, and warfarin showed the smallest concentration range for the pharmaceutical compounds. Sulfamethoxazole (a sulfonamide) showed the greatest concentration range and highest concentration, and sulfathiozole (also a sulfonamide) showed the smallest concentration range for the antibiotic compounds. Two hormones, 17 beta-estradiol (E2) and estrone (E1), were detected in influent. Samples were also tested for detection of organic wastewater compounds, pharmaceutical compounds, antibiotic compounds, and hormones in effluent. Indole showed the greatest concentration range and highest concentration, and triphenyl phosphate showed the smallest concentration range for the organic wastewater compounds. Dehydronifedipine showed the greatest concentration range and highest concentration, and warfarin had the smallest concentration range for the pharmaceutical compounds. Anhydro-erythromycin (a macrolide degradation product) showed the greatest concentration range, and sulfadiazine (a sulfonamide) and tetracycline showed the lowest concentration ranges for the antibiotic compounds. One hormone, 17 beta-estradiol (E2), was det

Pharmacology of 13-cis-retinoic acid in humans.

PubMed

Kerr, I G; Lippman, M E; Jenkins, J; Myers, C E

1982-05-01

Vitamin A and its analogs (retinoids) have shown great promise for the chemoprevention of cancer as well as being a possible new class of chemotherapeutic agents. A Phase I and II trial of 13-cis-retinoic acid in advanced cancers was initiated, and the clinical pharmacology of the drug was studied. All patients received p.o. 13-cis-retinoic acid starting at 0.5 mg/kg/day, escalating over 4 weeks to a maximum dose of 8 mg/kg/day in divided doses. Although there was a linear correlation of plasma concentration with dose escalation, large inter-individual variations in peak plasma concentrations were noted. At the maximum drug dose, the mean peak plasma concentration was 4 X 10(-6) M. There was little drug accumulation on this schedule, as trough concentrations between p.o. doses often dropped below 1 X 10(-6) M. The drug was metabolized extensively to a metabolite, the concentrations of which exceeding parent 13-cis-retinoic acid concentrations with chronic dosing. Retinol concentrations were below the normal range.

Investigation of hydrate formation in the system H2-CH4-H2O at a pressure up to 250 MPa.

PubMed

Skiba, Sergei S; Larionov, Eduard G; Manakov, Andrey Y; Kolesov, Boris A; Kosyakov, Viktor I

2007-09-27

Phase equilibria in the system H2-CH4-H2O are investigated by means of differential thermal analysis within hydrogen concentration range 0-70 mol % and at a pressure up to 250 MPa. All the experiments were carried out under the conditions of gas excess. With an increase in hydrogen concentration in the initial gas mixture, decomposition temperature of the formed hydrates decreased. X-ray diffraction patterns and Raman spectra of the quenched hydrate samples obtained at a pressure of 20 MPA from a gas mixture containing 40 mol % hydrogen were recorded. It turned out that the hydrate has cubic structure I under these conditions. The Raman spectra showed that hydrogen molecules are not detected in the hydrate within the sensitivity of the method, that is, almost pure methane hydrate is formed. The general view of the phase diagram of the investigated system is proposed. A thermodynamic model was proposed to explain a decrease in hydrate decomposition temperature in the system with an increase in the concentration of hydrogen in the initial mixture.

Atmospheric bromoform at Cape Point, South Africa: an initial fixed-point data set on the African continent

NASA Astrophysics Data System (ADS)

Kuyper, Brett; Palmer, Carl J.; Labuschagne, Casper; Reason, Chris J. C.

2018-04-01

Bromoform mixing ratios in marine air were measured at Cape Point Global Atmospheric Watch Station, South Africa. This represents the first such bromoform data set recorded at this location. Manual daily measurements were made during a month-long field campaign (austral spring 2011) using a gas chromatograph-electron capture detector (GC-ECD) with a custom-built front end thermal desorption trap. The measured concentrations ranged between 4.4 and 64.6 (± 22.2 %) ppt with a mean of 24.8 ± 14.8 ppt. The highest mixing ratios recorded here occurred at, or shortly after, low tide. The diurnal cycle exhibited a morning and evening maximum with lower concentrations throughout the rest of the day. Initial analysis of the data presented indicates that the local kelp beds were the dominant source of the bromoform reported. A concentration-weighted trajectory analysis of the bromoform measurements suggests that two offshore source areas may exist. These source areas appear to be centred on the Agulhas retroflection and extend from St Helena Bay to the southwest.

Investigation of Room Temperature Mössbauer Spectroscopy and Initial Permeability Properties of Al3+ Substituted Cobalt Ferrites

NASA Astrophysics Data System (ADS)

Pandit, Rabia; Kaur, Pawanpreet; Sharma, K. K.; Hashim, Mohd.; Kumar, Ravi

In the present work, Al3+ substituted cobalt ferrites (CoFe2‑xAlxO4, x=0.2, 0.4, 0.6, 0.8) have been synthesized via standard solid-state reaction technique. The incorporation of Al3+ ions in cobalt ferrite has been shown to play an important role in modifying the magnetic properties. The room temperature (300K) 57Fe Mössbauer spectra reveals that the studied samples show two characteristic ferromagnetic zeeman sextets at A and B-sites at lower Al3+ ion concentration (i.e., up to x=0.4). However, a paramagnetic relaxation has been noted for higher Al3+ substitution (for x=0.6 and 0.8) samples. The dependence of the Mössbauer parameters such as isomer shift, quadrupole splitting, line width and magnetic hyperfine field on Al3+ ion concentration has also been noted. The variations in initial permeability over a wide frequency range (125kHz to 30MHz) at 300K have been recorded. The fairly constant values of initial permeability and the low values of the relative loss factor of the order of 10‑4 to 10‑5 over the wide frequency range are the important findings of the present work. The observed low values of relative loss factor at high frequencies suggest that the studied ferrites are promising materials to be used in microwave applications.

Comparison of intracellular drug retention, DNA damage and cytotoxicity of derivatives of doxorubicin and daunorubicin in a human colon adenocarcinoma cell line (LoVo).

PubMed

Belvedere, G; Suarato, A; Geroni, C; Giuliani, F C; D'Incalci, M

1989-11-01

Formation of DNA single strand breaks (SSB) was assayed by alkaline elution in LoVo cells treated with doxorubicin, daunorubicin and six derivatives of these drugs modified either in the chromophore or the sugar. Seven compounds showed a biphasic relationship (initial increase and then a decrease) for the formation of DNA-SSB over the concentration range 0.05-10 micrograms/ml. At a drug concentration in the range causing an increase of DNA damage very fast repair of DNA-SSB was observed for 4'-deoxydoxorubicin and 4-demethoxydaunorubicin; the kinetics of DNA-SSB investigated after drug removal at a drug concentration reducing DNA-SSB showed a time dependent increase of DNA damage for both drugs although with different patterns. 4'-Deoxydoxorubicin reduced the effect of radiations on the rate of elution of DNA in a way resembling the formation of DNA interstrand cross links (ISC) at concentrations at which DNA-SSB were reduced. DNA-ISC were not produced by chemical reactions occurring during sample processing for alkaline elution and this derivative was not metabolized by LoVo cells. The IC50 of the anthracyclines were on a several log range, though for most of the derivatives the cytotoxicity curve showed a plateau at growth inhibition of about 15-30% at increasing intracellular drug levels. A relationship between DNA damage and cytotoxicity was observed only in a very small range of DNA-SSB. It is likely that the different effects of these anthracyclines on the formation of DNA-SSB depend on a qualitatively different interaction between drug-DNA and topoisomerase II when the drug concentration is raised.

Sulfur content of hybrid poplar cuttings fumigated with sulfur dioxide

Treesearch

Keith F. Jensen

1975-01-01

Hybrid poplar cuttings were fumigated with sulfur dioxide ranging in concentration from 0.1 to 5 ppm for periods of 5 to 80 hours. At the end of the fumigation periods, the cuttings were harvested and the sulfur and chlorophyll contents of the leaves were measured. At 0.1 ppm and 0.25 ppm the sulfur content initially increased, but decreased as fumigation continued. At...

Distributed sensor for water and pH measurements using fiber optics and swellable polymeric systems

NASA Astrophysics Data System (ADS)

Michie, W. C.; Culshaw, B.; McKenzie, I.; Konstantakis, M.; Graham, N. B.; Moran, C.; Santos, F.; Bergqvist, E.; Carlstrom, B.

1995-01-01

We report on the design, construction and test of a generic form of sensor for making distributed measurements of a range of chemical parameters. The technique combines optical time-domain reflectometry with chemically sensitive water-swellable polymers (hydrogels). Initial experiments have concentrated on demonstrating a distributed water detector; however, gels have been developed that enable this sensor to be

Accumulation and depletion of liver copper stores in dairy cows challenged with a Cu-deficient diet and oral and injectable forms of Cu supplementation.

PubMed

Balemi, S C; Grace, N D; West, D M; Smith, S L; Knowles, S O

2010-06-01

To quantify the capacity of the liver to respond to a Cu-deficient diet and various forms of Cu supplementation in dairy cows with high Cu status. Sixty non-pregnant, non lactating mixed-age Friesian dairy cows were fed baled silage for 116 days, containing 5.8 mg Cu/kg dry matter (DM), that provided an inadequate Cu intake. They were either unsupplemented (Control); or treated thrice weekly orally with solutions containing the equivalent of 150 mg Cu/day as copper sulphate pentahydrate (CS), copper amino chelate (CAC), or copper glycinate (CG); 16 g Cu as CuO wire particles, administered in an intra-ruminal bolus on Day 0; or 100 mg Cu as calcium copper edetate, administered by S/C injection on Days 0 and 58. On Days -5, 14, 28, 58, 86 and 116, liver biopsies and blood samples were obtained for determination of Cu. Mean initial concentrations of Cu in liver for all groups was 827 (SE 42) micromol/kg fresh tissue. In control cows, this decreased to 552 micromol/kg on Day 116, and averaged 670 micromol/kg over the length of the trial. Oral forms of Cu supplementation increased overall mean concentrations in liver to 960 (SE 79), 1,050 (SE 81) and 1,100 (SE 84) micromol/kg for CS, CAC and CG, respectively, but there was no difference between form of supplement. Mean concentrations were significantly increased by bolus treatment, but not by injection. Concentrations of Cu in serum in all groups decreased from 12.1 (SE 0.3) to 10.4 (SE 0.6) micromol/L by Day 116, with no differences due to treatments. The initial concentration of Cu in liver significantly affected the rate of accumulation of Cu among cows supplemented orally. In cows with an initial concentration <1,100 micromol/kg, the average increase was 4.1 micromol/kg fresh tissue/day, whereas rates were variable, even negative, when initial concentrations were >1,100 micromol/kg. Release of Cu over 116 days in cows given the bolus was calculated to be equivalent to an oral intake of CS of 106 mg Cu/day. In dairy cows with a high Cu status fed a Cu-deficient diet, responses to supplementation with two chelated forms of Cu administrated orally were similar to those due to CS. Copper as CuO was about 77% as effective as oral supplementation with chemically similar inorganic Cu. Initial concentrations of Cu in liver influenced the rate of accumulation following oral supplementation. Changes in concentrations of Cu in liver were readily observed following oral supplementation over a wide range of initial concentrations, whereas these changes could not be detected in serum. The liver is thus a good index of the Cu status of dairy cows.

Dissipation and runoff transport of metazachlor herbicide in rapeseed cultivated and uncultivated plots in field conditions.

PubMed

Mantzos, Nikolaos; Hela, Dimitra; Karakitsou, Anastasia; Antonopoulou, Maria; Konstantinou, Ioannis

2016-10-01

The environmental fate of metazachlor herbicide was investigated under field conditions in rapeseed cultivated and uncultivated plots, over a period of 225 days. The cultivation was carried out in silty clay soil plots with two surface slopes, 1 and 5 %. The herbicide was detectable in soil up to 170 days after application (DAA), while the dissipation rate was best described by first-order kinetics and its half-life ranged between 10.92 and 12.68 days. The herbicide was detected in the soil layer of 10-20 cm from 5 to 48 DAA, and its vertical movement can be described by the continuous stirred tank reactor (CSTR) in series model. Relatively low amounts of metazachlor (less than 0.31 % of the initial applied active ingredient) were transferred by runoff water. More than 80 % of the total losses were transferred at the first runoff event (12 DAA), with herbicide concentrations in runoff water ranging between 70.14 and 79.67 μg L -1 . Minor amounts of the herbicide (less than 0.07 % of the initial applied active ingredient) were transferred by the sediment, with a maximum concentration of 0.57 μg g -1 (12 DAA), in plots with 5 % inclination. Finally, in rapeseed plants, metazachlor was detected only in the first sampling (28 DAA) at concentrations slightly higher than the limit of quantification; when in seeds, no residues of the herbicide were detected.

Polymer brush covalently attached to OH-functionalized mica surface via surface-initiated ATRP: control of grafting density and polymer chain length.

PubMed

Lego, Béatrice; François, Marion; Skene, W G; Giasson, Suzanne

2009-05-05

The controlled grafting density of poly(tert-butyl acrylate) was studied on OH-activated mica substrates via surface-initiated atom-transfer radical polymerization (ATRP). By properly adjusting parameters such as the immobilization reaction time and the concentration of an ATRP initiator, a wide range of initiator surface coverages and hence polymer densities on mica were possible. The covalently immobilized initiator successfully promoted the polymerization of tert-butyl acrylate on mica surfaces. The resulting polymer layer thickness was measured by AFM using a step-height method. Linear relationships of the polymer thickness with respect to the molecular weight of the free polymer and with respect to the monomer conversion were observed, suggesting that ATRP is well controlled and relatively densely end-grafted layers were obtained. The polymer grafting density controlled by adjusting the initiator surface coverage was confirmed by the polymer layer swelling capacity and film thickness measurements.

Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for semivolatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and alkylated PAH homolog groups in sediment

USGS Publications Warehouse

Burkhardt, M.R.; Zaugg, S.D.; Burbank, T.L.; Olson, M.C.; Iverson, J.L.

2005-01-01

Polycyclic aromatic hydrocarbons (PAH) are recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This paper describes a method to determine the distribution of PAH and alkylated homolog groups in sediment samples. Pressurized liquid extraction (PLE), coupled with solid-phase extraction (SPE) cleanup, was developed to decrease sample preparation time, to reduce solvent consumption, and to minimize background interferences for full-scan GC-MS analysis. Recoveries from spiked Ottawa sand, environmental stream sediment, and commercially available topsoil, fortified at 1.5-15 ??g per compound, averaged 94.6 ?? 7.8%, 90.7 ?? 5.8% and 92.8 ?? 12.8%, respectively. Initial method detection limits for single-component compounds ranged from 20 to 302 ??g/kg, based on 25 g samples. Results from 28 environmental sediment samples, excluding homologs, show 35 of 41 compounds (85.4%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, 2,6-dimethylnaphthalene, was detected in 23 of the 28 (82%) environmental samples with a concentration ranging from 15 to 907 ??g/kg. The results from the 28 environmental sediment samples for the homolog series showed that 27 of 28 (96%) samples had at least one homolog series present at concentrations ranging from 20 to 89,000 ??g/kg. The most frequently detected homolog series, C2-alkylated naphthalene, was detected in 26 of the 28 (93%) environmental samples with a concentration ranging from 25 to 3900 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction also are compared. ?? 2005 Elsevier B.V. All rights reserved.

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

Kaur, Ramneek; Tripathi, S. K., E-mail: surya@pu.ac.in, E-mail: surya-tr@yahoo.com

This paper reports the synthesis and electrical characterization of CdSe-PMMA nanocomposite. CdSe-PMMA nanocomposite has been prepared by ex-situ technique through chemical route. The influence of three different Ag doping concentrations on the electrical properties has been studied in the temperature range ∼ 303-353 K. Transmission electron micrograph reveals the spherical morphology of the CdSe nanoparticles and their proper dispersion in the PMMA matrix. The electrical conduction of the polymer nanocomposites is through thermally activated process with single activation energy. With Ag doping, initially the activation energy increases upto 0.2 % Ag doping concentration but with further increase in Ag concentration, itmore » decreases. This behavior has been discussed on the basis of randomly oriented grain boundaries and defect states. Thus, the results indicate that the transport properties of the polymer nanocomposites can be tailored by controlled doping concentration.« less

Mineral profiling of ostrich (Struthio camelus) seminal plasma and its relationship with semen traits and collection day.

PubMed

Smith, A M J; Bonato, M; Dzama, K; Malecki, I A; Cloete, S W P

2018-06-01

Successful assisted reproduction techniques, with specific focus on in vitro semen storage for artificial insemination, are dependent on certain key elements which includes the biochemical profiling of semen. The objective of this study was to complete an ostrich seminal plasma (SP) evaluation by inductively coupled plasma mass spectrometry (ICP-MS) among seven males at different daily intervals (day 1, 3, 7, 11, 15, 19, 21, 23, 25, 26, 27, 28) for a period of 28 days during spring (August to September) for mineral profiling. The effect of collection day and male on sperm concentration, semen volume and seminal plasma volume, was explored as well as the relationships amongst these specific sperm traits and SP minerals. Variation amongst SP mineral concentrations, accounted for by the fixed effects of sperm concentration, semen volume, seminal plasma volume, collection day and male, ranged from 18% to 77%. Male had the largest effect on variation in SP minerals, namely: phosphorus (P), potassium (K), calcium (Ca), sodium (Na), boron (B), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), barium (Ba), arsenic (As) and selenium (Se). Sperm concentration instigated fluctuations of P, magnesium (Mg), B, zinc (Zn), Fe, aluminium (Al), Se, manganese (Mn) and lead (Pb). Semen volume had an effect on Na, K, B, Pb and Ba while seminal plasma volume only influenced variation in Na. There were fluctuations among collection days of specific micro minerals, Ni and Mo, with initial Ni concentrations being relatively greater and Mo at lesser concentrations. Semen volume, seminal plasma volume and sperm concentration varied amongst males. Sperm concentrations during the initial collection days, 1 and 3, were less than that for days 7 to 28. Significant variation of SP minerals and sperm characteristics among ejaculates and males suggest an association of these specific elements with sperm function and are, therefore, considered to be of potential importance to success of assisted reproduction technology for the ostrich. The relationship amongst sperm concentration and collection day confirms the need to conduct an initial period of collection to stabilise a greater sperm concentration to optimise sperm numbers for artificial insemination purposes. Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of initial cell concentration on xylose fermentation by Pichia stipitis

Treesearch

Frank K. Agbogbo; Guillermo Coward-Kelly; Mads Torry-Smith; Kevin Wenger; Thomas W. Jeffries

2007-01-01

Xylose was fermented using Pichia stipitis CBS 6054 at different initial cell concentrations. A high initial cell concentration increased the rate of xylose utilization, ethanol formation, and the ethanol yield. The highest ethanol concentration of 41.0 g/L and a yield of 0.38 g/g was obtained using an initial cell concentration of 6.5 g/L. Even though more xylitol was...

Methyl mercury toxicity in plant cultures: modification of resistance and demethylation by light and/or 2,4-dichlorophenoxyacetic acid

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

Czuba, M.

1987-04-01

Cultures of Daucus carota, Ca-68-10, and Lactuca sativa, Le-67, were grown at increasing methyl mercury (MeHg) concentrations ranging from initial doses of 0.05 to 5.0 micrograms/ml per day for 4 days with or without 0.15 microgram/ml 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence or absence of light. The presence of 2,4-D interacted with light synergistically in the expression of MeHg toxicity within the whole range of concentrations. Demethylation patterns increased or decreased depending on the species, the 2,4-D concentration in the medium, and methyl mercury concentration used in the treatment. Lettuce was more sensitive to this interaction than carrot. In lettuce,more » the presence of 2,4-D in the light lowered the concentration of total Hg (or MeHg) required to reduce growth by 50%, about 13 times relative to that in the dark (i.e., it sensitized the cells). In the absence of 2,4-D the pattern was reversed. In carrot the pattern was similar but less pronounced. This suggests that, in these cell populations, MeHg toxicity is partly a hormone-mediated and light-sensitive event.« less

A novel inter-fibre light coupling sensor probe using plastic optical fibre for ethanol concentration monitoring at initial production rate

NASA Astrophysics Data System (ADS)

Memon, Sanober F.; Lewis, Elfed; Pembroke, J. Tony; Chowdhry, Bhawani S.

2017-04-01

A novel, low cost and highly sensitive optical fibre probe sensor for concentration measurement of ethanol solvent (C2H5OH) corresponding to bio-ethanol production rate by an algae is reported. The principle of operation of the sensor is based on inter-fibre light coupling through an evanescent field interaction to couple the light between two multimode fibres mounted parallel to each other at a minimum possible separation i.e. < 1mm. The sensor was fabricated using a low cost 1000um plastic optical fibre (POF) and was characterized for real time measurement in the broadband spectrum including visible and near infra-red. The wavelength dependency of this sensor design was also investigated by post processing analysis of real time data and hence the optimum wavelength range determined. The proposed sensor has shown significant response in the range of 0.005 - 0.1 %v/v (%volume/volume or volume concentration) which depicts the high sensitivity for monitoring very minute changes in concentration corresponding refractive index changes of the solution. Numerically, sensor has shown the sensitivity of 21945 intensity counts/%v/v or 109.7 counts per every 0.0050 %v/v.

Groundwater quality of the Gulf Coast aquifer system, Houston, Texas, 2007-08

USGS Publications Warehouse

Oden, Jeannette H.; Oden, Timothy D.; Szabo, Zoltan

2010-01-01

In the summers of 2007 and 2008, the U.S. Geological Survey (USGS), in cooperation with the City of Houston, Texas, completed an initial reconnaissance-level survey of naturally occurring contaminants (arsenic, other selected trace elements, and radionuclides) in water from municipal supply wells in the Houston area. The purpose of this reconnaissance-level survey was to characterize source-water quality prior to drinking water treatment. Water-quality samples were collected from 28 municipal supply wells in the Houston area completed in the Evangeline aquifer, Chicot aquifer, or both. This initial survey is part of ongoing research to determine concentrations, spatial extent, and associated geochemical conditions that might be conducive for mobility and transport of these constituents in the Gulf Coast aquifer system in the Houston area. Samples were analyzed for major ions (calcium, magnesium, potassium, sodium, bromide, chloride, fluoride, silica, and sulfate), selected chemically related properties (residue on evaporation [dissolved solids] and chemical oxygen demand), dissolved organic carbon, arsenic species (arsenate [As(V)], arsenite [As(III)], dimethylarsinate [DMA], and monomethylarsonate [MMA]), other trace elements (aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, lead, lithium, manganese, molybdenum, nickel, selenium, silver, strontium, thallium, vanadium, and zinc), and selected radionuclides (gross alpha- and beta-particle activity [at 72 hours and 30 days], carbon-14, radium isotopes [radium-226 and radium-228], radon-222, tritium, and uranium). Field measurements were made of selected physicochemical (relating to both physical and chemical) properties (oxidation-reduction potential, turbidity, dissolved oxygen concentration, pH, specific conductance, water temperature, and alkalinity) and unfiltered sulfides. Dissolved organic carbon and chemical oxygen demand are presented but not discussed in the report. Physicochemical properties, major ions, and trace elements varied considerably. The pH ranged from 7.2 to 8.1 (median 7.6); specific conductance ranged from 314 to 856 microsiemens per centimeter at 25 degrees Celsius, with a median of 517 microsiemens per centimeter; and alkalinity ranged from 126 to 324 milligrams per liter as calcium carbonate (median 167 milligrams per liter). The range in oxidation-reduction potential was large, from -212 to 244 millivolts, with a median of -84.6 millivolts. The largest ranges in concentration for filtered major ion constituents were obtained for cations sodium and calcium and for anions chloride and bicarbonate (bicarbonate was calculated from the measured alkalinity). Filtered arsenic was detected in all 28 samples, ranging from 0.58 to 15.3 micrograms per liter (median 2.5 micrograms per liter), and exceeded the maximum contaminant level established by the U.S. Environmental Protection Agency of 10 micrograms per liter in 2 of the 28 samples. As(III) was the most frequently detected arsenic specie. As(III) concentrations ranged from less than 0.6 to 14.9 micrograms arsenic per liter. The range in concentrations for the arsenic species As(V) was from less than 0.8 to 3.3 micrograms arsenic per liter. Barium, boron, lithium, and strontium were detected in quantifiable (equal to or greater than the laboratory reporting level) concentrations in all samples and molybdenum in all but one sample. Filtered iron, manganese, nickel, and vanadium were each detected in at least 18 of the 28 samples. All other selected trace elements were each detected in 16 or fewer samples. Radionuclides were detected in most samples. The gross alpha-particle activities at 30 days and 72 hours ranged from R-0.94 to 15.5 and R-1.1 to 17.2 picocuries per liter, respectively ('R' indicates nondetected result less than the sample-specific critical level). The combined radium (radium-226 plus radium-228) concentrations ranged from an estimat

Surface Complexation Modeling of Fluoride Adsorption by Soil and the Role of Dissolved Aluminum on Adsorption

NASA Astrophysics Data System (ADS)

Padhi, S.; Tokunaga, T.

2017-12-01

Adsorption of fluoride (F) on soil can control the mobility of F and subsequent contamination of groundwater. Hence, accurate evaluation of adsorption equilibrium is a prerequisite for understanding transport and fate of F in the subsurface. While there have been studies for the adsorption behavior of F with respect to single mineral constituents based on surface complexation models (SCM), F adsorption to natural soil in the presence of complexing agents needs much investigation. We evaluated the adsorption processes of F on a natural granitic soil from Tsukuba, Japan, as a function of initial F concentration, ionic strength, and initial pH. A SCM was developed to model F adsorption behavior. Four possible surface complexation reactions were postulated with and without including dissolved aluminum (Al) and Al-F complex sorption. Decrease in F adsorption with the increase in initial pH was observed in between the initial pH range of 4 to 9, and a decrease in the rate of the reduction of adsorbed F with respect to the increase in the initial pH was observed in the initial pH range of 5 to 7. Ionic strength variation in the range of 0 to 100mM had insignificant effect on F removal. Changes in solution pH were observed by comparing the solution before and after F adsorption experiments. At acidic pH, the solution pH increased, whereas at alkaline pH, the solution pH decreased after equilibrium. The SCM including dissolved Al and the adsorption of Al-F complex can simulate the experimental results quite successfully. Also, including dissolved Al and the adsorption of Al-F complex to the model explained the change in solution pH after F adsorption.

Use of egg yolk antibody (IgY) as an immunoanalytical tool in the detection of Indian cobra (Naja naja naja) venom in biological samples of forensic origin.

PubMed

Brunda, G; Sashidhar, R B; Sarin, R K

2006-08-01

An immunoglobulin Y (IgY) based indirect double antibody sandwich enzyme linked immunosorbent assay (ELISA) was developed for the detection of Indian cobra (Naja naja naja) venom in the biological samples of forensic origin. Polyclonal antibodies were raised and purified from chick egg yolk and rabbit serum. The cobra venom was sandwiched between immobilized affinity purified IgY and the rabbit IgG. The detection concentration of cobra venom was in the range of 0.1 to 300ng. The calibration plot was based on linear regression analysis (y=0.2581x+0.4375, r(2)=0.9886). The limit of detection of the assay was found to be 0.1ng. The coefficient of variation (CV) of different concentrations of working range in inter (n=6) and intra-assay (n=6) was observed to be less than 10%. The recovery of venom was found to be in the range of 80-99%, when different concentrations (0.002, 0.1, 0.2, 1, and 2microg) of cobra venom were spiked to pooled normal human serum (ml(-1)). No cross reactivity was observed with krait and viper venom in the immunoassay system in the concentration range of 0.1-1000ng. The method was initially, validated by analyzing specimens (autopsy) of experimental rats injected with cobra venom (1.2mgkg(-1) body mass). Further, human specimens (autopsy and biopsy) of snake bite victims of forensic origin were also analyzed. The methodology developed may find diagnostic application in forensic laboratories.

The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity.

PubMed

Heggers, John P; Cottingham, John; Gusman, Jean; Reagor, Lee; McCoy, Lana; Carino, Edith; Cox, Robert; Zhao, Jian-Gang; Reagor, Lana

2002-06-01

Recent testimonials report grapefruit-seed extract, or GSE (Citricidal) to be effective against more than 800 bacterial and viral strains, 100 strains of fungus, and a large number of single and multicelled parasites. This study investigated GSE for antibacterial activity at varying time intervals and concentration levels and tissue toxicity at varying concentrations in an effort to determine if a concentration existed that was both microbicidal and nontoxic and in what period of time. Gram-negative and gram-positive isolates were introduced into graduated dilutions of GSE (twofold concentrations ranging from 1:1, through 1:512) for determination of bacterial activity. In vitro assays with human skin fibroblast cells were also performed at the same dilutions to determine toxicity. These tests indicated that from the 1:1 through the 1:128 concentrations, GSE remained toxic as well as bactericidal. However, test results indicated that at the 1:512 dilution, GSE remained bactericidal, but completely nontoxic. The initial data shows GSE to have antimicrobial properties against a wide range of gram-negative and gram-positive organisms at dilutions found to be safe. With the aid of scanning transmission electron microscopy (STEM), the mechanism of GSE's antibacterial activity was revealed. It was evident that GSE disrupts the bacterial membrane and liberates the cytoplasmic contents within 15 minutes after contact even at more dilute concentrations.

Aerobic biodegradation of amphoteric amine-oxide-based surfactants: Effect of molecular structure, initial surfactant concentration and pH.

PubMed

Ríos, Francisco; Lechuga, Manuela; Fernández-Serrano, Mercedes; Fernández-Arteaga, Alejandro

2017-03-01

The present study was designed to provide information regarding the effect of the molecular structure of amphoteric amine-oxide-based surfactants and the initial surfactant concentration on their ultimate biodegradation. Moreover, given this parameter's pH-dependence, the effect of pH was also investigated. Three amine-oxide-based surfactants with structural differences in their hydrophobic alkyl chain were tested: Lauramine oxide (AO-R 12 ), Myristamine oxide (AO-R 14 ) and Cocamidopropylamine oxide (AO-Cocoamido). We studied the ultimate biodegradation using the Modified OECD Screening Test at initial surfactant concentrations ranged from 5 to 75 mg L -1 and at pH levels from 5 to 7.4. The results demonstrate that at pH 7.4, amine-oxide-based surfactants are readily biodegradable. In this study, we concluded that ω-oxidation can be assumed to be the main biodegradation pathway of amine-oxides and that differences in the biodegradability between them can be explained by the presence of an amide group in the alkyl chain of AO-Cocoamido; the CN fission of the amide group slows down their mineralization process. In addition, the increase in the concentration of the surfactant from 5 to 75 mg L -1 resulted in an increase in the final biodegradation of AO-R 12 and AO-R 14 . However, in the case of AO-Cocoamido, a clear relationship between the concentration and biodegradation cannot be stated. Conversely, the biodegradability of AO-R 12 and AO-R 14 was considerably lower in an acid condition than at a pH of 7.4, whereas AO-Cocoamido reached similar percentages in acid conditions and at a neutral pH. However, microorganisms required more time to acclimate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polymerization Behavior and Polymer Properties of Eosin-Mediated Surface Modification Reactions.

PubMed

Avens, Heather J; Randle, Thomas James; Bowman, Christopher N

2008-10-17

Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40 wt% acrylamide with MDEA which yielded four to eight fold thicker films (maximum polymer thickness increased from 180 nm to 1420 nm) and generated visible films from 5-fold lower eosin surface densities (2.8 vs. 14 eosins/µm(2)) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities.

Polymerization Behavior and Polymer Properties of Eosin-Mediated Surface Modification Reactions

PubMed Central

Avens, Heather J.; Randle, Thomas James; Bowman, Christopher N.

2008-01-01

Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40 wt% acrylamide with MDEA which yielded four to eight fold thicker films (maximum polymer thickness increased from 180 nm to 1420 nm) and generated visible films from 5-fold lower eosin surface densities (2.8 vs. 14 eosins/µm2) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities. PMID:19838291

Equilibrium and thermodynamic analysis of zinc ions adsorption by olive oil mill solid residues.

PubMed

Hawari, A; Rawajfih, Z; Nsour, N

2009-09-15

This work investigated the equilibrium batch dynamics of using olive oil mill solid residues as an adsorbent for zinc removal from aqueous solutions. It was found that a sorbent concentration of 4 g L(-1) achieved the best removal percentage and the best sorbent capacity. Adsorption equilibrium was reached in 60 min for an initial zinc concentration of 0.25 mmol/L and 180 min for an initial zinc concentration of 1-3 mmol/L. A particle size of olive mill residue ranging from 0.85 to 1.18 mm was used in the study. It was found that the maximum adsorption capacity of zinc was at a pH value of 5.0. It was found that q(max) for zinc ions, was 5.63, 6.46, and 7.11 mg g(-1) at temperature values of 298, 308, and 328 K, respectively. The data pertaining to the sorption dependence upon metal ion concentration could be fitted to a Langmuir isotherm model. The second-order kinetic model provided the best correlation of the data. The change in entropy (DeltaS degrees ) and heat of adsorption (DeltaH degrees ) for zinc ions adsorption on olive mill solid residues were estimated as -1419 kJ kg(-1)K(-1) and 4.7 kJ kg(-1), respectively. The examined low-cost adsorbent could offer an effective way to decrease zinc ions concentration in wastewater.

Design and Initial Characterization of the SC-200 Proteomics Standard Mixture

PubMed Central

Bauman, Andrew; Higdon, Roger; Rapson, Sean; Loiue, Brenton; Hogan, Jason; Stacy, Robin; Napuli, Alberto; Guo, Wenjin; van Voorhis, Wesley; Roach, Jared; Lu, Vincent; Landorf, Elizabeth; Stewart, Elizabeth; Kolker, Natali; Collart, Frank; Myler, Peter; van Belle, Gerald

2011-01-01

Abstract High-throughput (HTP) proteomics studies generate large amounts of data. Interpretation of these data requires effective approaches to distinguish noise from biological signal, particularly as instrument and computational capacity increase and studies become more complex. Resolving this issue requires validated and reproducible methods and models, which in turn requires complex experimental and computational standards. The absence of appropriate standards and data sets for validating experimental and computational workflows hinders the development of HTP proteomics methods. Most protein standards are simple mixtures of proteins or peptides, or undercharacterized reference standards in which the identity and concentration of the constituent proteins is unknown. The Seattle Children's 200 (SC-200) proposed proteomics standard mixture is the next step toward developing realistic, fully characterized HTP proteomics standards. The SC-200 exhibits a unique modular design to extend its functionality, and consists of 200 proteins of known identities and molar concentrations from 6 microbial genomes, distributed into 10 molar concentration tiers spanning a 1,000-fold range. We describe the SC-200's design, potential uses, and initial characterization. We identified 84% of SC-200 proteins with an LTQ-Orbitrap and 65% with an LTQ-Velos (false discovery rate = 1% for both). There were obvious trends in success rate, sequence coverage, and spectral counts with protein concentration; however, protein identification, sequence coverage, and spectral counts vary greatly within concentration levels. PMID:21250827

Design and initial characterization of the SC-200 proteomics standard mixture.

PubMed

Bauman, Andrew; Higdon, Roger; Rapson, Sean; Loiue, Brenton; Hogan, Jason; Stacy, Robin; Napuli, Alberto; Guo, Wenjin; van Voorhis, Wesley; Roach, Jared; Lu, Vincent; Landorf, Elizabeth; Stewart, Elizabeth; Kolker, Natali; Collart, Frank; Myler, Peter; van Belle, Gerald; Kolker, Eugene

2011-01-01

High-throughput (HTP) proteomics studies generate large amounts of data. Interpretation of these data requires effective approaches to distinguish noise from biological signal, particularly as instrument and computational capacity increase and studies become more complex. Resolving this issue requires validated and reproducible methods and models, which in turn requires complex experimental and computational standards. The absence of appropriate standards and data sets for validating experimental and computational workflows hinders the development of HTP proteomics methods. Most protein standards are simple mixtures of proteins or peptides, or undercharacterized reference standards in which the identity and concentration of the constituent proteins is unknown. The Seattle Children's 200 (SC-200) proposed proteomics standard mixture is the next step toward developing realistic, fully characterized HTP proteomics standards. The SC-200 exhibits a unique modular design to extend its functionality, and consists of 200 proteins of known identities and molar concentrations from 6 microbial genomes, distributed into 10 molar concentration tiers spanning a 1,000-fold range. We describe the SC-200's design, potential uses, and initial characterization. We identified 84% of SC-200 proteins with an LTQ-Orbitrap and 65% with an LTQ-Velos (false discovery rate = 1% for both). There were obvious trends in success rate, sequence coverage, and spectral counts with protein concentration; however, protein identification, sequence coverage, and spectral counts vary greatly within concentration levels.

Mixed metal oxide nanoparticles inhibit growth of Mycobacterium tuberculosis into THP-1 cells.

PubMed

Jafari, A R; Mosavi, T; Mosavari, N; Majid, A; Movahedzade, F; Tebyaniyan, M; Kamalzadeh, M; Dehgan, M; Jafari, S; Arastoo, S

2016-12-01

Humans have been in a constant battle with tuberculosis (TB). Currently, overuse of antibiotics has resulted in the spread of multidrug-resistant Mycobacterium tuberculosis (MDR), leading to antibiotic ineffectiveness at controlling the spread of TB infection in host cells and especially macrophages. Additionally, the Mycobacterium tuberculosis (Mtb) has developed methods to evade the immune system and survive. With the discovery of nanoparticle (NP)-based drugs, it is necessary to research their anti-mycobacterial properties and bactericidal mechanisms. In this study, we synthesized mixed metal oxide NPs and tested their ability to inhibit Mtb growth into macrophages and investigated the cytotoxic effects of NPs in THP-1 cells. Silver (Ag) NPs and zinc oxide (ZnO) NPs were synthesized by chemical reduction and chemical deposition in aqueous solution, and the diffraction light scattering, scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible light-absorption spectra were used to identify NP properties. Ag and ZnO NPs were mixed together at a ratio of 8 ZnO /2 Ag and diluted into Löwenstein-Jensen medium followed by the addition of bacteria and incubation for 28days at 37°C. The toxicity of NPs to THP-1 cells was assessed by MTT test, and macrophages were infected with Mtb for 4h at 37°C under 5% CO 2 . Nano-sized particles were estimated at ∼30-80nm, and the initial concentration of Ag NPs and ZnO NPs were estimated at ∼20ppm and ∼60ppm. The minimal inhibitory concentration ratio of 8 ZnO /2 Ag NPs against Mtb was detected at ∼1/32 of the initial concentration. Ag NPs in the range of concentrations exhibited no anti-Mtb effects, whereas ZnO NPs showed potent antibacterial activity at ∼1/128 of the initial concentration. ZnO NPs at all concentrations showed cytotoxic activity, whereas 100% of THP-1 cells remained viable in the presence of Ag NPs at ∼1/32 and ∼1/64 of the initial concentrations. However, at ratios of 8 ZnO /2 Ag , ∼39.94% of the cells at ∼1/16 of the initial concentration remained viable, with 100% of THP-1 cells at ∼1/32 of the initial concentration remaining viable. Although Ag NPs exhibited low cytotoxicity, they were unable to inhibit Mtb growth in vitro. ZnO NPs exhibited strong anti-Mtb activity and inhibited bacterial growth, but exhibited high cytotoxicity to human macrophage cells. By mixing Ag and ZnO NPs at a ratio of 8 ZnO /2 Ag , we acquired a mixture that exhibited potent antibacterial activity against Mtb and no cytotoxic effects on THP-1 cells, resulting in inhibition of both in vitro and ex vivo Mtb growth Figs. 1-3, Tables 1-3. Copyright © 2016.

Characterization and modeling of sediment settling, consolidation, and suspension to optimize coastal Louisiana restoration

NASA Astrophysics Data System (ADS)

Sha, X.; Xu, K.; Bentley, S. J.; Robichaux, P. A.

2018-04-01

Many research efforts have been undertaken over many decades in the field of Louisiana coastal restoration, but long-term experiments for sediment suspension and consolidation in diversion-receiving basins are still limited, despite significance of this topic to ongoing restoration strategies. Sediment samples were collected from two active diversions on the Mississippi River: West Bay, a semi-enclosed bay located on the Mississippi River Delta and fed by the West Bay Diversion, and from Big Mar pond, a receiving basin of the Caernarvon freshwater diversion from the lower Mississippi River, Louisiana, USA. A dual-core Gust Erosion Microcosm System was used to measure time-series (0.5, 1, 2, 3, 4, 5, and 6-months after initial settling) erodibility at seven shear stress regimes (0.01-0.60 Pa) using experimental cores prepared with two initial sediment concentrations (60 and 120 kg m-3). A 230-cm tall settling column with nine sampling ports was used to measure the consolidation rates for initial sediment concentrations ranging from fluid mud (10 kg m-3) to dredge effluent (120 kg m-3), in combination with two levels of salinity (1 and 5). The erodibility of West Bay sediment decreased with increasing time of consolidation. The critical shear stress for resuspension increased from 0.2 Pa after 2 months to 0.45 Pa after 4 months of consolidation. The consolidation rates were inversely and exponentially related to initial sediment concentrations. Consolidation tests in salinity of 1 generally settled faster than that in salinity of 5, and consolidation tests with low sediment concentration tests generally settled faster than high-concentration tests. An exponential coefficient was added in the Sanford (2008) model to better predict the consolidation profile of both rapid early settling and slow self-weight consolidation processes. Our study suggests that enclosed basin, low salinity, relatively low sediment concentration and minimized disturbance for 4 months all favor of mud deposition and retention, and these factors should be considered in the design of coastal restoration projects such as dredging effluent placements and sediment diversions.

Enhanced decolorization of methyl orange in aqueous solution using iron-carbon micro-electrolysis activation of sodium persulfate.

PubMed

Li, Peng; Liu, Zhipeng; Wang, Xuegang; Guo, Yadan; Wang, Lizhang

2017-08-01

Reactivity of sodium persulfate (PS) in the decolorization of methyl orange (MO) in aqueous solution using an iron-carbon micro-electrolysis (ICE) method was investigated. The effects of sodium persulfate doses, pH, Fe-to-C mass ratios, initial MO concentration as well as the reaction temperature were comprehensively studied in batch experiments. The ICE-PS coupled process was more suitable for wide ranges of pH, initial MO concentration and reaction temperature, accompanied by the reduction of Fe compared ICE. The MO removal efficiency improved substantially by ICE-PS technique, 76.03% for ICE and 91.27% for ICE-PS at experimental conditions of pH 3.0, Fe-to-C mass ratio 3:1, PS addition 10 mM and initial MO concentration 0.61 mM. Furthermore, the biodegradability index (BI) dramatically increased from 0.26 to 0.65. The binary hydroxyl and sulfate radicals that non-selectively degrade MO to the derivatives with small molecules are ascribed to ICE-PS method as detected by the UV-vis spectra. The PS activation resource was Fe 2+ through the hydroxyl radical quenching reaction by the additive tert-butanol (TBA). This study provides an in-depth theoretical understanding of the development and wide commercial application of the ICE technology to refractory industrial dye wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Degradation kinetics and mechanism of trace nitrobenzene by granular activated carbon enhanced microwave/hydrogen peroxide system.

PubMed

Tan, Dina; Zeng, Honghu; Liu, Jie; Yu, Xiaozhang; Liang, Yanpeng; Lu, Lanjing

2013-07-01

The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H202) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H202 process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H202 dosage 10 mg/L, pH 6.85 and temperature (60 +/- 5)degrees C), the degradation rate of NB was 0.05214 min-1when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0-12.0. At H202 dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H202 process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation.

Gibberellin inhibitors improve embryogenic tissue initiation in conifers.

PubMed

Pullman, Gerald S; Mein, J; Johnson, S; Zhang, Y

2005-02-01

Somatic embryogenesis (SE), the most promising technology to multiply high-value coniferous trees from advanced breeding and genetic engineering programs, is expected to play an important role in increasing productivity, sustainability, and uniformity of future forests in the United States. For commercial use, SE technology must work with a variety of genetically diverse trees. Initiation in loblolly pine (LP; Pinus taeda L.), our main focus species, is often recalcitrant for desirable genotypes. Initiation of LP, slash pine (SP; Pinus elliottii), Douglas-fir (DF; Pseudotsuga menziesii), and Norway spruce (NS; Picea abies) were improved through the use of paclobutrazol, a gibberellin synthesis inhibitor. Paclobutrazol was effective at concentrations ranging from 0.25 mg/l to 3.0 mg/l (0.85-10.2 microM) and optimal in LP at 1.0 mg/l. Using control media (no paclobutrazol) and 0.33-1.0 mg/l paclobutrazol, initiation percentages in LP, SP, DF, and NS were improved from 37.7% to 44.2% (across experiments), 19.3% to 28.5%, 16.9% to 23.7%, and 38.8% to 48.5%, respectively. Other gibberellin inhibitors such as flurprimidol, chlormequat-Cl, and daminozide also caused statistically significant increases in LP initiation when added to the medium at concentrations of 0.34, 10.0, and 1.0 microM, respectively. No detrimental effects on subsequent embryo development were observed when 29 new initiations from medium without GA inhibitor and 28 new initiations from medium containing paclobutrazol were tracked through culture capture, liquid culture establishment, cotyledonary embryo development, and germination.

Shock wave and modeling study of the thermal decomposition reactions of pentafluoroethane and 2-H-heptafluoropropane.

PubMed

Cobos, C J; Sölter, L; Tellbach, E; Troe, J

2014-06-07

The thermal decomposition reactions of CF3CF2H and CF3CFHCF3 have been studied in shock waves by monitoring the appearance of CF2 radicals. Temperatures in the range 1400-2000 K and Ar bath gas concentrations in the range (2-10) × 10(-5) mol cm(-3) were employed. It is shown that the reactions are initiated by C-C bond fission and not by HF elimination. Differing conclusions in the literature about the primary decomposition products, such as deduced from experiments at very low pressures, are attributed to unimolecular falloff effects. By increasing the initial reactant concentrations in Ar from 60 to 1000 ppm, a retardation of CF2 formation was observed while the final CF2 yields remained close to two CF2 per C2F5H or three CF2 per C3F7H decomposed. This is explained by secondary bimolecular reactions which lead to comparably stable transient species like CF3H, releasing CF2 at a slower rate. Quantum-chemical calculations and kinetic modeling help to identify the reaction pathways and provide estimates of rate constants for a series of primary and secondary reactions in the decomposition mechanism.

Hydroxide ion-mediated synthesis of monodisperse dopamine-melanin nanospheres.

PubMed

Cho, Soojeong; Kim, Shin-Hyun

2015-11-15

Dopamine-melanin nanospheres are promising materials for photoprotection, structural coloration, and thermoregulation due to their unusual optical and chemical properties. Here, we report the experimental parameters which influence size of dopamine-melanin nanospheres and uniformity. Dopamine precursors are oxidatively polymerized in basic aqueous medium. Therefore, concentration of hydroxide ions significantly influences reaction rate and size of nanospheres. To investigate the effect of hydroxide ions, we adjust three different parameters which affect pH of medium: concentration of sodium hydroxide and dopamine hydrochloride, and reaction temperature. At constant temperature, concentration of hydroxide ions is linearly proportional to initial reaction rates which determine the number of nuclei for nanosphere growth. Temperature alters not only initial reaction rate but also diffusivity of molecules, leading to deviation from the relation between the reaction rate and the number of nuclei. The diameter of dopamine-melanin nanospheres can be readily controlled in a range of 80-490nm through adjusting concentration of dopamine precursor, while maintaining uniform-size distribution and dispersion stability. The synthesized nanospheres are analyzed to confirm the chemical structure, which is composed of approximately 6 indole units. Moreover, surface and chemical properties of the nanospheres are characterized to provide valuable information for surface modification and application. Copyright © 2015 Elsevier Inc. All rights reserved.

[Effect of nano-selenium on the activities of glutathione peroxidase and type-I deiodinase in the liver of weanling pigs].

PubMed

Zhang, Hongmei; Xia, Meisheng; Hu, Caihong

2007-02-01

To study the effects of nano elemental selenium (Nano-Se) or sodium selenite (Na2SeO3) on the activities of glutathione peroxidase (GSH-Px) and Type-I deiodinase in the liver. A total of 234 weanling pigs (Duroc x Landrace x Yorkshire) at an average initial body weight of 8.3 kg were allocated to 13 treatments. The thirteen dietary treatments were basal diet only (containing 0.04 mg/kg Se), basal diet + 0.1, 0.2, 0.3, 0.4, 0.5, 1.0 mg/kg Se as Na2SeO3 or Nano-Se, respectively. The results were as follows: Supplementation with 1.0 mg/ kg Se as Na2SeO3 reduced (P < 0.05) growth performance and GSH-Px activities as compared with the addition of a concentration range of 0.20-0.40 mg/kg Se. When Nano-Se was added to the diet, the growth and GSH-Px activities remained steady at the peak value as at a concentration of 1.0 mg/kg Se; There were no difference in the activities of GSH-Px between the treatments of Nano-Se and Na2SeO3 when added concentration of Se was 0.10-0.40 mg/kg. The pigs had higher (P < 0.05) activities of GSH-Px at a concentration range of 0.50 and 1.0 mg/kg as Nano-Se than Na2SeO3; Supplentation with Se increased the activity of Type- I deiodinase in liver, however, the increased extent was affected by neither Se sources nor added concentration of Se. The results implicated that for the best concentration range of Weinberg curve, Nano-Se is wider than Na2SeO3.

Fault orientations in extensional and conjugate strike-slip environments and their implications

USGS Publications Warehouse

Thatcher, W.; Hill, D.P.

1991-01-01

Seismically active conjugate strike-slip faults in California and Japan typically have mutually orthogonal right- and left-lateral fault planes. Normal-fault dips at earthquake nucleation depths are concentrated between 40?? and 50??. The observed orientations and their strong clustering are surprising, because conventional faulting theory suggests fault initiation with conjugate 60?? and 120?? intersecting planes and 60?? normal-fault dip or fault reactivation with a broad range of permitted orientations. The observations place new constraints on the mechanics of fault initiation, rotation, and evolutionary development. We speculate that the data could be explained by fault rotation into the observed orientations and deactivation for greater rotation or by formation of localized shear zones beneath the brittle-ductile transition in Earth's crust. Initiation as weak frictional faults seems unlikely. -Authors

Strategies of Nitrosomonas europaea 19718 to counter low dissolved oxygen and high nitrite concentrations.

PubMed

Yu, Ran; Chandran, Kartik

2010-03-04

Nitrosomonas europaea is a widely studied chemolithoautotrophic ammonia oxidizing bacterium. While significant work exists on the ammonia oxidation pathway of N. europaea, its responses to factors such as dissolved oxygen limitation or sufficiency or exposure to high nitrite concentrations, particularly at the functional gene transcription level are relatively sparse. The principal goal of this study was to investigate responses at the whole-cell activity and gene transcript levels in N. europaea 19718 batch cultures, which were cultivated at different dissolved oxygen and nitrite concentrations. Transcription of genes coding for principal metabolic pathways including ammonia oxidation (amoA), hydroxylamine oxidation (hao), nitrite reduction (nirK) and nitric oxide reduction (norB) were quantitatively measured during batch growth, at a range of DO concentrations (0.5, 1.5 and 3.0 mg O2/L). Measurements were also conducted during growth at 1.5 mg O2/L in the presence of 280 mg-N/L of externally added nitrite. Several wide ranging responses to DO limitation and nitrite toxicity were observed in N. europaea batch cultures. In contrast to our initial hypothesis, exponential phase mRNA concentrations of both amoA and hao increased with decreasing DO concentrations, suggesting a mechanism to metabolize ammonia and hydroxylamine more effectively under DO limitation. Batch growth in the presence of 280 mg nitrite-N/L resulted in elevated exponential phase nirK and norB mRNA concentrations, potentially to promote utilization of nitrite as an electron acceptor and to detoxify nitrite. This response was in keeping with our initial hypothesis and congruent with similar responses in heterotrophic denitrifying bacteria. Stationary phase responses were distinct from exponential phase responses in most cases, suggesting a strong impact of ammonia availability and metabolism on responses to DO limitation and nitrite toxicity. In general, whole-cell responses to DO limitation or nitrite toxicity, such as sOUR or nitrite reduction to nitric oxide (NO) did not parallel the corresponding mRNA (nirK) profiles, suggesting differences between the gene transcription and enzyme translation or activity levels. The results of this study show that N. europaea possesses specific mechanisms to cope with growth under low DO concentrations and high nitrite concentrations. These mechanisms are additionally influenced by the physiological growth state of N. europaea cultures and are possibly geared to enable more efficient substrate utilization or nitrite detoxification.

Distribution of mercury in the environment at Almaden, Spain

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

Hildebrand, S.G.; Huckabee, J.W.; Diaz, F.S.

1980-10-01

An ecological survey of the concentration and distribution of mercury in terrestrial and aquatic systems near the mercury mine at Almaden, Spain, was initiated in 1974. Field studies were completed in 1977, and chemical analyses were completed in 1979. Sample collection at Almaden followed a trophic-level approach in which certain compartments were sampled at a given instant in time (fall 1974, fall 1975, spring 1976, fall 1976, spring 1977). Mean total mercury concentration in terrestrial plants (8 taxa combined) ranged from >100 ..mu..g/g within 0.5 km of the mine to 1 ..mu..g/g 20 km distant from the mine. Different plantmore » species had different affinities for mercury, but moss species usually had higher total mercury concentration than vascular plants. Woody plants were lower in mercury concentration than forbs. Total mercury concentration in muscle, brain, kidney, and liver tissue from mice was highest at a station near the stream receiving liquid effluent from the mine (mean total mercury at this station ranging from 0.18 ..mu..g/g in muscle to 4.74 ..mu..g/g in kidney). Approximately 15 to 30% of total mercury in mouse tissue was in the methylated form. Total mercury concentration in muscle tissue from house sparrows varied inversely with distance from the mine, with highest concentrations exceeding 0.1 ..mu..g/g. Approximately 1 to 4% of total mercury in sparrow muscle was in the methylated form.« less

Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe by solid-liquid-coexisting annealing of a-GeSn/c-Si structures

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

Sadoh, Taizoh, E-mail: sadoh@ed.kyushu-u.ac.jp; Chikita, Hironori; Miyao, Masanobu

2015-09-07

Ultra-low temperature (≤300 °C) growth of Ge-rich SiGe on Si substrates is strongly desired to realize advanced electronic and optical devices, which can be merged onto Si large-scale integrated circuits (LSI). To achieve this, annealing characteristics of a-GeSn/c-Si structures are investigated under wide ranges of the initial Sn concentrations (0%–26%) and annealing conditions (300–1000 °C, 1 s–48 h). Epitaxial growth triggered by SiGe mixing is observed after annealing, where the annealing temperatures necessary for epitaxial growth significantly decrease with increasing initial Sn concentration and/or annealing time. As a result, Ge-rich (∼80%) SiGe layers with Sn concentrations of ∼2% are realized by ultra-low temperature annealingmore » (300 °C, 48 h) for a sample with the initial Sn concentration of 26%. The annealing temperature (300 °C) is in the solid-liquid coexisting temperature region of the phase diagram for Ge-Sn system. From detailed analysis of crystallization characteristics and composition profiles in grown layers, it is suggested that SiGe mixing is generated by a liquid-phase reaction even at ultra-low temperatures far below the melting temperature of a-GeSn. This ultra-low-temperature growth technique of Ge-rich SiGe on Si substrates is expected to be useful to realize next-generation LSI, where various multi-functional devices are integrated on Si substrates.« less

Solutions of the chemical kinetic equations for initially inhomogeneous mixtures.

NASA Technical Reports Server (NTRS)

Hilst, G. R.

1973-01-01

Following the recent discussions by O'Brien (1971) and Donaldson and Hilst (1972) of the effects of inhomogeneous mixing and turbulent diffusion on simple chemical reaction rates, the present report provides a more extensive analysis of when inhomogeneous mixing has a significant effect on chemical reaction rates. The analysis is then extended to the development of an approximate chemical sub-model which provides much improved predictions of chemical reaction rates over a wide range of inhomogeneities and pathological distributions of the concentrations of the reacting chemical species. In particular, the development of an approximate representation of the third-order correlations of the joint concentration fluctuations permits closure of the chemical sub-model at the level of the second-order moments of these fluctuations and the mean concentrations.

Techno-economic analysis of different pretreatment processes for lignocellulosic-based bioethanol production.

PubMed

da Silva, André Rodrigues Gurgel; Torres Ortega, Carlo Edgar; Rong, Ben-Guang

2016-10-01

In this work, a method based on process synthesis, simulation and evaluation has been used to setup and study the industrial scale lignocellulosic bioethanol productions processes. Scenarios for pretreatment processes of diluted acid, liquid hot water and ammonia fiber explosion were studied. Pretreatment reactor temperature, catalyst loading and water content as well as solids loading in the hydrolysis reactor were evaluated regarding its effects on the process energy consumption and bioethanol concentration. The best scenarios for maximizing ethanol concentration and minimizing total annual costs (TAC) were selected and their minimum ethanol selling price was calculated. Ethanol concentration in the range of 2-8% (wt.) was investigated after the pretreatment. The best scenarios maximizing the ethanol concentration and minimizing TAC obtained a reduction of 19.6% and 30.2% respectively in the final ethanol selling price with respect to the initial base case. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measurement of atmospheric ammonia at a dairy using differential optical absorption spectroscopy in the mid-ultraviolet

NASA Astrophysics Data System (ADS)

Mount, George H.; Rumburg, Brian; Havig, Jeff; Lamb, Brian; Westberg, Hal; Yonge, David; Johnson, Kristen; Kincaid, Ronald

Ammonia is the most abundant basic gas in the atmosphere, and after N 2 and N 2O is the most abundant nitrogen-containing specie (Seinfeld and Pandis, 1998. Atmospheric Chemistry and Physics: from air pollution to climate changes. Wiley, New York). Typical concentrations of ammonia in the boundary layer range from <1 part per billion by volume (ppbv) in the free continental troposphere to parts per million (ppmv) levels over animal waste lagoons and near animal stalls. Agricultural activities are the dominant global source of ammonia emissions and a major environmental concern. In the US, ≈85% of ammonia emissions come from livestock operations (EPA Trends, 1998. www.epa.gov/ttn/chief/trends98/chapter2.pdf). Dairy farms constitute a large fraction of the livestock inventory. Current estimates of ammonia emissions to the atmosphere are characterized by a high degree of uncertainty, and so it is very important to obtain better estimates of ammonia emissions. We are working at the Washington State University research dairy to quantify ammonia emissions and investigate the effects of various mitigation strategies on those emissions. We describe here a new instrument utilizing the differential optical absorption spectroscopy (DOAS) technique to measure ammonia in the mid-ultraviolet with a detectability limit of about 1 ppb. DOAS avoids many of the problems that have thwarted past ammonia concentration measurements. Initial results show concentrations in the barn/concrete yard areas in the tens of parts per million range, over the slurry lagoons of hundreds of parts per billion to low parts per million, and low parts per million levels after initial slurry applications onto pastureland. Future papers will report on emission fluxes from the various parts of the dairy and the results of mitigation strategies; we show here initial data results. For a recent review of ammonia volatilization from dairy farms, see Bussink and Oenema (Nutrient Cycling in Agroecosystems 51(1998) 19).

Transdermal gelation of methacrylated macromers with near-infrared light and gold nanorods

NASA Astrophysics Data System (ADS)

Gramlich, William M.; Holloway, Julianne L.; Rai, Reena; Burdick, Jason A.

2014-01-01

Injectable hydrogels provide locally controlled tissue bulking and a means to deliver drugs and cells to the body. The formation of hydrogels in vivo may involve the delivery of two solutions that spontaneously crosslink when mixed, with pH or temperature changes, or with light (e.g., visible or ultraviolet). With these approaches, control over the kinetics of gelation, introduction of the initiation trigger (e.g., limited penetration of ultraviolet light through tissues), or alteration of the material physical properties (e.g., mechanics) may be difficult to achieve. To overcome these limitations, we used the interaction of near-infrared (NIR) light with gold nanorods (AuNRs) to generate heat through the photothermal effect. NIR light penetrates tissues to a greater extent than other wavelengths and provides a means to indirectly initiate radical polymerization. Specifically, this heating coupled with a thermal initiator (VA-044) produced radicals that polymerized methacrylated hyaluronic acid (MeHA) and generated hydrogels. A range of VA-044 concentrations changed the gelation time, yielding a system stable at 37 ° C for 22 min that gels quickly (˜3 min) when heated to 55 ° C. With a constant irradiation time (10 min) and laser power (0.3 W), different VA-044 and AuNR concentrations tuned the compressive modulus of the hydrogel. By changing the NIR irradiation time we attained a wide range of moduli at a set solution composition. In vivo mouse studies confirmed that NIR laser irradiation through tissue could gel an injected precursor solution transdermally.

Concentrations of metals in feathers and blood of nestling Black-Crowned Night-Herons (Nycticorax nycticorax) in Chesapeake and Delaware Bays

USGS Publications Warehouse

Golden, N.H.; Rattner, B.A.; McGowan, P.C.; Parsons, K.C.; Ottinger, M.A.

2003-01-01

Over the past decade, destruction and degradation of wetland habitat has contributed to the decline of wading bird colonies on the Atlantic Coast. In 1998, an initial assessment of the possible contribution of metal pollution to declining heron populations in Chesapeake and Delaware Bays was conducted. Study sites included two heronries in industrialized locations (Pea Patch Island, DE and Baltimore Harbor, MD), and a reference site (Holland Island) remotely located in the southern Chesapeake Bay. Concentrations of 19 metals, metalloids, and trace elements were examined in blood and breast feathers of 14-16 day old nestling black-crowned night-herons. Metal concentrations in blood were low and showed few site differences, though mercury was elevated at Pea Patch Island as compared to other sites. In feathers, metal concentrations appeared to be in the low to moderate range at all sites, though limited data exist for interpreting pollutant concentrations in feathers of nestling wading birds. Where differences were detected, concentrations at Pea Patch Island were consistently greater than those at Baltimore Harbor and Holland Island. Feathers collected at Pea Patch Island had significantly greater concentrations of aluminum, barium, iron, lead, magnesium, and manganese, but were generally found to be within the range of concentrations detected in other nestling birds, where that information was available. Based on these results, metal pollution does not appear to be an immediate threat to BCNH colonies at these two locations, though future monitoring of some elements (Pb, Mn, and Al) may be warranted.

Validating the Effectiveness of Switching the Vancomycin TDM Analysis Software Based on the Predictive Accuracy.

PubMed

Imai, Shungo; Yamada, Takehiro; Ishiguro, Nobuhisa; Miyamoto, Takenori; Kagami, Keisuke; Tomiyama, Naoki; Niinuma, Yusuke; Nagasaki, Daisuke; Suzuki, Koji; Yamagami, Akira; Kasashi, Kumiko; Kobayashi, Masaki; Iseki, Ken

2017-01-01

Based on the predictive performance in our previous study, we switched the therapeutic drug monitoring (TDM) analysis software for dose setting of vancomycin (VCM) from "Vancomycin MEEK TDM analysis software Ver2.0" (MEEK) to "SHIONOGI-VCM-TDM ver.2009" (VCM-TDM) in January 2015. In the present study, our aim was to validate the effectiveness of the changing VCM TDM analysis software in initial dose setting of VCM. The enrolled patients were divided into two groups, each having 162 patients in total, who received VCM with the initial dose set using MEEK (MEEK group) or VCM-TDM (VCM-TDM group). We compared the rates of attaining the therapeutic range (trough value; 10-20 μg/mL) of serum VCM concentration between the groups. Multivariate logistic regression analysis was performed to confirm that changing the VCM TDM analysis software was an independent factor related to attaining the therapeutic range. Switching the VCM TDM analysis software from MEEK to VCM-TDM improved the rate of attaining the therapeutic range by 21.6% (MEEK group: 42.6% vs. VCM-TDM group: 64.2%, p<0.01). Patient age ≥65 years, concomitant medication (furosemide) and the TDM analysis software used VCM-TDM were considered to be independent factors for attaining the therapeutic range. These results demonstrated the effectiveness of switching the VCM TDM analysis software from MEEK to VCM-TDM for initial dose setting of VCM.

The Nevada Rural Ozone Initiative: Field measurements of surface ozone in rural settings

NASA Astrophysics Data System (ADS)

Fine, R.; Gustin, M. S.; Weiss-Penzias, P. S.; Jaffe, D. A.; Peterson, C.

2011-12-01

The Nevada Rural Ozone Initiative (NVROI) focuses on measuring ozone and other parameters at rural sites across Nevada. The project was prompted by observations of elevated ozone concentrations at Great Basin National Park (GBNP), a remote location at the eastern boundary of the state. Past CASTNET data collected at GBNP demonstrated that the area will be out of attainment if the new ozone NAAQS are established at any values between 60 and 70 ppb. To examine the ozone sources we have augmented the CASTNET data at GBNP with measurements at additional sites. NVROI field sites are situated between 1390 and 2080 meters above sea level along transects consistent with the prevailing wind directions across the state. Data collection began in July 2011. Measurements indicate significant variability in the diel pattern of ozone concentrations between field sites suggesting that site specific physicochemical characteristics, free tropospheric inputs, and regional transport of air pollutants all influence observed values at these background sites. Ancillary gas, particulate matter, and meteorological parameters will be coupled with trajectory analyses to investigate the influence of local, regional, and long range sources on background ozone concentrations.

Nickel(II) biosorption from aqueous solutions by shrimp head biomass.

PubMed

Hernández-Estévez, Alejandro; Cristiani-Urbina, Eliseo

2014-11-01

The present study evaluates the capacity of shrimp (Farfantepenaeus aztecus) head to remove toxic Ni(II) ions from aqueous solutions. Relevant parameters that could affect the biosorption process, such as shrimp head pretreatment, solution pH level, contact time and initial Ni(II) concentration, were studied in batch systems. An increase in Ni(II) biosorption capacity and a reduction in the time required to reach Ni(II) biosorption equilibrium was manifested by shrimp head biomass pretreated by boiling in 0.5 N NaOH for 15 min; this biomass was thereafter denominated APSH. The optimum biosorption level of Ni(II) ions onto APSH was observed at pH 7.0. Biosorption increased significantly with rising initial Ni(II) concentration. In terms of biosorption dynamics, the pseudo-second-order kinetic model described Ni(II) biosorption onto APSH best. The equilibrium data adequately fitted the Langmuir isotherm model within the studied Ni(II) ion concentration range. According to this isotherm model, the maximum Ni(II) biosorption capacity of APSH was 104.22 mg/g. Results indicate that APSH could be used as a low-cost, environmentally friendly, and promising biosorbent with high biosorption capacity to remove Ni(II) from aqueous solutions.

An acetone breath analyzer using cavity ringdown spectroscopy: an initial test with human subjects under various situations

NASA Astrophysics Data System (ADS)

Wang, Chuji; Surampudi, Anand B.

2008-10-01

We have developed a portable breath acetone analyzer using cavity ringdown spectroscopy (CRDS). The instrument was initially tested by measuring the absorbance of breath gases at a single wavelength (266 nm) from 32 human subjects under various conditions. A background subtraction method, implemented to obtain absorbance differences, from which an upper limit of breath acetone concentration was obtained, is described. The upper limits of breath acetone concentration in the four Type 1 diabetes (T1D) subjects, tested after a 14 h overnight fast, range from 0.80 to 3.97 parts per million by volume (ppmv), higher than the mean acetone concentration (0.49 ppmv) in non-diabetic healthy breath reported in the literature. The preliminary results show that the instrument can tell distinctive differences between the breath from individuals who are healthy and those with T1D. On-line monitoring of breath gases in healthy people post-exercise, post-meals and post-alcohol-consumption was also conducted. This exploratory study demonstrates the first CRDS-based acetone breath analyzer and its potential application for point-of-care, non-invasive, diabetic monitoring.

Cytochemical Organization of the Retino-Suprachiasmatic System.

DTIC Science & Technology

1992-08-03

cytoplasmic Ca2+ concentrations with periods ranging from 7 to 20 seconds. This periodic oscillation could be initiated by in vitro application of glutamate...Neurons and glia respond to neurotransmitter application with a variety of Ca2+ responses; both may play a role in the function of the SCN, and their...Can a single cell show a circadian rhythm, or are a greater number needed. Several mathematical models of clock function (e.g.Pavlidis) suggest that

Deposition Ice Nuclei Concentration at Different Temperatures and Supersaturations

NASA Astrophysics Data System (ADS)

López, M. L.; Avila, E.

2013-05-01

Ice formation is one of the main processes involved in the initiation of precipitation. Some aerosols serve to nucleate ice in clouds. They are called ice nuclei (IN) and they are generally solid particles, insoluble in water. At temperatures warmer than about -36°C the only means for initiation of the ice phase in the atmosphere involves IN, and temperature and supersaturation required to activate IN are considered as key information for the understanding of primary ice formation in clouds. The objective of this work is to quantify the IN concentration at ground level in Córdoba City, Argentina, under the deposition mode, that is to say that ice deposits on the IN directly from the vapor phase. It happens when the environment is supersaturated with respect to ice and subsaturated with respect to liquid water. Ice nuclei concentrations were measured in a cloud chamber placed in a cold room with temperature control down to -35°C. The operating temperature was varied between -15°C and -30°C. Ice supersaturation was ranged between 2 and 20 %. In order to quantify the number of ice particles produced in each experiment, a dish containing a supercooled solution of cane sugar, water and glycerol was placed on the floor of the cloud chamber. The activated IN grew at the expense of vapor until ice crystals were formed and these then fell down onto the sugar solution. Once there, these crystals could grow enough to be counted easily with a naked eye after a period of about three minutes, when they reach around 2 mm in diameter. In order to compare the present results with previously reported results, the data were grouped in three different ranges of supersaturation: the data with supersaturations between 2 and 8 %, the data with supersaturations between 8 and 14% and the data with supersaturations between 14 and 20 %. In the same way, in order to analize the behavior of IN concentration with supersaturation, the data were grouped for three different temperatures, the data with temperatures between -15°C and -20°C, the data with temperatures between -20°C and -25°C and the data with temperatures between -25°C and -30°C. The results confirm that for each temperature range, the concentration of IN increases at higher supersaturation, and show the tendency of the IN concentration to increase with increasing ice supersaturation. Based on previous parameterizations, a combination of IN concentration in relation with temperature and ice supersaturation is proposed in this work. As far as we know, this is among the first work to measure and parameterize the concentration of deposition ice nuclei in the Southern Hemisphere.

Ultracentrifugation in the Concentration and Detection of Enteroviruses

PubMed Central

Cliver, Dean O.; Yeatman, John

1965-01-01

Ultracentrifugation has been evaluated as a method of concentrating enteroviruses from suspensions whose initial titers ranged from 1.7 × 108 to 1.6 × 10-2 plaque-forming units (PFU) per ml. A technique employing a “trap” of 0.1 ml of 2% gelatin solution at the point at which the pellet forms in tubes for the number 30 and number 50 rotors of the Spinco model L preparative ultracentrifuge has been tested and found to have a number of advantages. Qualitative studies have been performed to determine the sensitivity of the ultracentrifuge technique in detecting the presence of enteroviruses in very dilute suspensions. There was found to be at least a 50% probability of detecting virus present initially at levels as low as 0.12 PFU per ml by means of the number 50 rotor. The input level for similar results with the number 30 rotor was found to be 0.025 PFU per ml. PMID:14325278

Ammonia nitrogen removal from aqueous solution by local agricultural wastes

NASA Astrophysics Data System (ADS)

Azreen, I.; Lija, Y.; Zahrim, A. Y.

2017-06-01

Excess ammonia nitrogen in the waterways causes serious distortion to environment such as eutrophication and toxicity to aquatic organisms. Ammonia nitrogen removal from synthetic solution was investigated by using 40 local agricultural wastes as potential low cost adsorbent. Some of the adsorbent were able to remove ammonia nitrogen with adsorption capacity ranging from 0.58 mg/g to 3.58 mg/g. The highest adsorption capacity was recorded by Langsat peels with 3.58 mg/g followed by Jackfruit seeds and Moringa peels with 3.37 mg/g and 2.64 mg/g respectively. This experimental results show that the agricultural wastes can be utilized as biosorbent for ammonia nitrogen removal. The effect of initial ammonia nitrogen concentration, pH and stirring rate on the adsorption process were studied in batch experiment. The adsorption capacity reached maximum value at pH 7 with initial concentration of 500 mg/L and the removal rate decreased as stirring rate was applied.

Bioremediation of 60Co from simulated spent decontamination solutions.

PubMed

Rashmi, K; Sowjanya, T Naga; Mohan, P Maruthi; Balaji, V; Venkateswaran, G

2004-07-26

Bioremediation of 60Co from simulated spent decontamination solutions by utilizing different biomass of (Neurospora crassa, Trichoderma viridae, Mucor recemosus, Rhizopus chinensis, Penicillium citrinum, Aspergillus niger and, Aspergillus flavus) fungi is reported. Various fungal species were screened to evaluate their potential for removing cobalt from very low concentrations (0.03-0.16 microM) in presence of a high background of iron (9.33 mM) and nickel (0.93 mM) complexed with EDTA (10.3 mM). The different fungal isolates employed in this study showed a pickup of cobalt in the range 8-500 ng/g of dry biomass. The [Fe]/[Co] and [Ni]/[Co] ratios in the solutions before and after exposure to the fungi were also determined. At micromolar level the cobalt pickup by many fungi especially the mutants of N. crassa is seen to be proportional to the initial cobalt concentration taken in the solution. However, R. chinensis exhibits a low but iron concentration dependent cobalt pickup. Prior saturating the fungi with excess of iron during their growth showed the presence of selective cobalt pickup sites. The existence of cobalt specific sorption sites is shown by a model experiment with R. chinensis wherein at a constant cobalt concentration (0.034 microM) and varying iron concentrations so as to yield [Fe/Co]initial ratios in solution of 10, 100, 1000 and 287000 have all yielded a definite Co pickup capacity in the range 8-47 ng/g. The presence of Cr(III)EDTA (3 mM) in solution along with complexed Fe and Ni has not influenced the cobalt removal. The significant feature of this study is that even when cobalt is present in trace level (sub-micromolar) in a matrix of high concentration (millimolar levels) of iron, nickel and chromium, a situation typically encountered in spent decontamination solutions arising from stainless steel based primary systems of nuclear reactors, a number of fungi studied in this work showed a good sensitivity for cobalt pickup. Copyright 2004 Elsevier B.V.

Reclamation of cadmium-contaminated soil using dissolved organic matter solution originating from wine-processing waste sludge.

PubMed

Liu, Cheng-Chung; Chen, Guan-Bu

2013-01-15

Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, serious loss of nutrients from soil is a major drawback of the washing. Distillery sludge can be used to prepare a dissolved organic matter (DOM) solution by extracting its organic constituents with alkaline solutions. This study employed DOM solutions to remediate Cd-contaminated soil (with concentrations up to 21.5 mg kg(-1)) and determine the factors affecting removal of Cd, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with pH 3.0 and 1250 mg L(-1) DOM solution, about 80% and 81% of Cd were removed from the topsoil at 27 °C and subsoil at 40 °C, respectively. To summarize the changes in fertility during DOM washing with various pH solutions: the increase in organic matter content ranged from 7.7% to 23.7%; cation exchange capacity (CEC) ranged from 4.6% to 13.9%; available ammonium (NNH(4)) content ranged from 39.4% to 2175%; and available phosphorus content ranged from 34.5% to 182%. Exchangeable K, Ca, and Mg remained in the topsoil after DOM washing, with concentrations of 1.1, 2.4, and 1.5 times higher than those treated with HCl solution at the same pH, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Haptoglobin concentrations in free-range and temporarily captive juvenile steller sea lions.

PubMed

Thomton, Jamie D; Mellish, Jo-Ann E

2007-04-01

Haptoglobin (Hp) is an acute-phase protein synthesized in the liver that circulates at elevated concentrations in response to tissue damage caused by inflammation, infection, and trauma. As part of a larger study, sera Hp concentrations were measured in temporarily captive (n = 21) and free-range (n = 38) western stock juvenile Steller sea lions (Eumetopias jubatus) sampled from 2003 to 2006. Baseline Hp concentration at time of capture was 133.3 +/- 17.4 mg/dl. Temporarily captive animals exhibited a 3.2-fold increase in Hp concentrations during the first 4 wk of captivity, followed by a return to entry levels by week 5. Haptoglobin levels were not influenced by age, season, or parasite load. There was a significant positive correlation between Hp concentrations and white blood cell count (P < 0.001) and globulin levels (P < 0.001) and a negative correlation to red blood cell count and hematocrit (P < 0.001 for both). There was no correlation between Hp levels and platelet count (P = 0.095) or hemoglobin (P = 0.457). Routine blubber biopsies collected under gas anesthesia did not produce a measurable Hp response. One animal with a large abscess had an Hp spike of 1,006.0 mg/dl that returned to entry levels after treatment. In conclusion, serum Hp levels correlate to the stable clinical health status observed during captivity, with moderate Hp response during capture and initial acclimation to captivity and acute response to inflammation and infection.

Trace element concentrations in liver of 16 species of cetaceans stranded on Pacific Islands from 1997 through 2013

PubMed Central

Hansen, Angela M. K.; Bryan, Colleen E.; West, Kristi; Jensen, Brenda A.

2016-01-01

The impacts of anthropogenic contaminants on marine ecosystems are a concern worldwide. Anthropogenic activities can enrich trace elements in marine biota to concentrations that may negatively impact organism health. Exposure to elevated concentrations of trace elements is considered a contributing factor in marine mammal population declines. Hawai'i is an increasingly important geographic location for global monitoring, yet trace element concentrations have not been quantified in Hawaiian cetaceans, and there is little trace element data for Pacific cetaceans. This study measured trace elements (Cr, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Hg, and Pb) in liver of 16 species of cetaceans that stranded on U.S. Pacific Islands from 1997–2013, using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) (n = 31), and direct mercury analysis atomic absorption spectrometry (DMA-AAS) (n = 43). Concentration ranges (µg/g wet mass fraction) for non-essential trace elements such as Cd (0.0031–58.93) and Hg (0.0062–1571.75) were much greater than essential trace elements such as Mn (0.590–17.31) and Zn (14.72–245.38). Differences were found among age classes in Cu, Zn, Hg, and Se concentrations. The highest concentrations of Se, Cd, Sn, Hg, and Pb were found in one adult female false killer whale (Pseudorca crassidens) at concentrations that are known to affect health in marine mammals. The results of this study establish initial trace element concentration ranges for Pacific cetaceans in the Hawaiian Islands region, provide insights into contaminant exposure of these marine mammals, and contribute to a greater understanding of anthropogenic impacts in the Pacific Ocean. PMID:26283019

Trace Element Concentrations in Liver of 16 Species of Cetaceans Stranded on Pacific Islands from 1997 through 2013.

PubMed

Hansen, Angela M K; Bryan, Colleen E; West, Kristi; Jensen, Brenda A

2016-01-01

The impacts of anthropogenic contaminants on marine ecosystems are a concern worldwide. Anthropogenic activities can enrich trace elements in marine biota to concentrations that may negatively impact organism health. Exposure to elevated concentrations of trace elements is considered a contributing factor in marine mammal population declines. Hawai'i is an increasingly important geographic location for global monitoring, yet trace element concentrations have not been quantified in Hawaiian cetaceans, and there is little trace element data for Pacific cetaceans. This study measured trace elements (Cr, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Hg, and Pb) in liver of 16 species of cetaceans that stranded on U.S. Pacific Islands from 1997 to 2013, using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) (n = 31), and direct mercury analysis atomic absorption spectrometry (DMA-AAS) (n = 43). Concentration ranges (μg/g wet mass fraction) for non-essential trace elements, such as Cd (0.0031-58.93) and Hg (0.0062-1571.75) were much greater than essential trace elements, such as Mn (0.590-17.31) and Zn (14.72-245.38). Differences were found among age classes in Cu, Zn, Hg, and Se concentrations. The highest concentrations of Se, Cd, Sn, Hg, and Pb were found in one adult female false killer whale (Pseudorca crassidens) at concentrations that are known to affect health in marine mammals. The results of this study establish initial trace element concentration ranges for Pacific cetaceans in the Hawaiian Islands region, provide insights into contaminant exposure of these marine mammals, and contribute to a greater understanding of anthropogenic impacts in the Pacific Ocean.

Fate and bioaccumulation of isoproturon in outdoor aquatic microcosms.

PubMed

Merlin, Gerard; Vuillod, Maryline; Lissolo, Thierry; Clement, Bernard

2002-06-01

To gain information concerning the ecotoxicity of isoproturon (IPU) on aquatic ecosystems, six experimental ponds of 5 m3 each were studied. All the experiments were conducted during the summer over two years. Three different types of ecosystems were tested in 1994 and one type of ecosystem was selected and repeated in 1995 with three replicates. In each case, the initial concentration of IPU contamination was set at 10 microg/L. The IPU concentration was determined in the water column and in different species (mainly plants) of the microcosms. A first-order kinetic decrease in IPU concentration was observed in 1994, with half-life ranging from 15 to 35 d, depending on the microcosms. This relatively fast decrease was also confirmed in 1995, but it reached a constant value after two months. A high variability of the IPU concentration was observed in exposed plants, with bioconcentration factors ranging from 100 to 1,200 with large coefficients of variation. The observed plant bioconcentration factors are higher than those predicted by usual numerical models, probably due to the specific binding of IPU on one protein of the photosynthetic apparatus. Our data show that bioconcentration does not occur in mollusks but is important in photosynthetic organisms. Plant bioconcentration and microbial biodegradation are the main processes involved in the IPU decay in our outdoor aquatic microcosms.

Differentiating high priority pathway-based toxicity from non ...

EPA Pesticide Factsheets

The ToxCast chemical screening approach enables the rapid assessment of large numbers of chemicals for biological effects, primarily at the molecular level. Adverse outcome pathways (AOPs) offer a means to link biomolecular effects with potential adverse outcomes at the level of the individual or population, thus enhancing the utility of the ToxCast effort for hazard assessment. Thus, efforts are underway to develop AOPs relevant to the pathway perturbations detected in ToxCast assays. However, activity (?‘hits’) determined for chemical-assay pairs may reflect target-specific activity relevant to a molecular initiating event of an AOP, or more generalized cell stress and cytotoxicity-mediated effects. Previous work identified a ?‘cytotoxic burst’ phenomenon wherein large numbers of assays begin to respond at or near concentrations that elicit cytotoxicity. The concentration range at which the “burst” occurs is definable, statistically. Consequently, in order to focus AOP development on the ToxCast assay targetswhich are most sensitive and relevant to pathway-specific effects, we conducted a meta-analysis to identify which assays were frequently responding at concentrations well below the cytotoxic burst. Assays were ranked by the fraction of chemical hits below the burst concentration range compared to the number of chemicals tested, resulting in a preliminary list of potentially important, target-specific assays. After eliminating cytotoxicity a

Application of High-Throughput In Vitro Assays for Risk-Based ...

EPA Pesticide Factsheets

Multiple drivers shape the types of human-health assessments performed on chemicals by U.S. EPA resulting in chemical assessments are “fit-for-purpose” ranging from prioritization for further testing to full risk assessments. Layered on top of the diverse assessment needs are the resource intensive nature of traditional toxicological studies used to test chemicals and the lack of toxicity information on many chemicals. To address these challenges, the Agency initiated the ToxCast program to screen thousands of chemicals across hundreds of high-throughput screening assays in concentrations-response format. One of the findings of the project has been that the majority of chemicals interact with multiple biological targets within a narrow concentration range and the extent of interactions increases rapidly near the concentration causing cytotoxicity. This means that application of high-throughput in vitro assays to chemical assessments will need to identify both the relative selectivity at chemicals interact with biological targets and the concentration at which these interactions perturb signaling pathways. The integrated analyses will be used to both define a point-of-departure for comparison with human exposure estimates and identify which chemicals may benefit from further studies in a mode-of-action or adverse outcome pathway framework. The application of new technologies in a risk-based, tiered manner provides flexibility in matching throughput and cos

20150325 - Application of High-Throughput In Vitro Assays for ...

EPA Pesticide Factsheets

Multiple drivers shape the types of human-health assessments performed on chemicals by U.S. EPA resulting in chemical assessments are “fit-for-purpose” ranging from prioritization for further testing to full risk assessments. Layered on top of the diverse assessment needs are the resource intensive nature of traditional toxicological studies used to test chemicals and the lack of toxicity information on many chemicals. To address these challenges, the Agency initiated the ToxCast program to screen thousands of chemicals across hundreds of high-throughput screening assays in concentrations-response format. One of the findings of the project has been that the majority of chemicals interact with multiple biological targets within a narrow concentration range and the extent of interactions increases rapidly near the concentration causing cytotoxicity. This means that application of high-throughput in vitro assays to chemical assessments will need to identify both the relative selectivity at chemicals interact with biological targets and the concentration at which these interactions perturb signaling pathways. The integrated analyses will be used to both define a point-of-departure for comparison with human exposure estimates and identify which chemicals may benefit from further studies in a mode-of-action or adverse outcome pathway framework. The application of new technologies in a risk-based, tiered manner provides flexibility in matching throughput and cos

Consequence of reputation in the Sznajd consensus model

NASA Astrophysics Data System (ADS)

Crokidakis, Nuno; Forgerini, Fabricio L.

2010-07-01

In this work we study a modified version of the Sznajd sociophysics model. In particular we introduce reputation, a mechanism that limits the capacity of persuasion of the agents. The reputation is introduced as a score which is time-dependent, and its introduction avoid dictatorship (all spins parallel) for a wide range of parameters. The relaxation time follows a log-normal-like distribution. In addition, we show that the usual phase transition also occurs, as in the standard model, and it depends on the initial concentration of individuals following an opinion, occurring at a initial density of up spins greater than 1/2. The transition point is determined by means of a finite-size scaling analysis.

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

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H 2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H 2 production, as well as the anode microbial community structure were investigated. The five compoundsmore » were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H 2 yield varied from 0.26 to 0.42 g H 2-COD/g COD removed in the anode, and the bioanode volume-normalized H 2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H 2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H 2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H 2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

Biotransformation of furanic and phenolic compounds with hydrogen gas production in a microbial electrolysis cell

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2015-10-27

In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H 2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H 2 production, as well as the anode microbial community structure were investigated. The five compoundsmore » were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H 2 yield varied from 0.26 to 0.42 g H 2-COD/g COD removed in the anode, and the bioanode volume-normalized H 2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H 2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H 2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H 2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

Biotransformation of Furanic and Phenolic Compounds with Hydrogen Gas Production in a Microbial Electrolysis Cell.

PubMed

Zeng, Xiaofei; Borole, Abhijeet P; Pavlostathis, Spyros G

2015-11-17

Furanic and phenolic compounds are problematic byproducts resulting from the breakdown of lignocellulosic biomass during biofuel production. The capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the substrate in the bioanode was assessed. The rate and extent of biotransformation of the five compounds and efficiency of H2 production, as well as the structure of the anode microbial community, were investigated. The five compounds were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode Coulombic efficiency was 44-69%, which is comparable to that of wastewater-fed MECs. The H2 yield varied from 0.26 to 0.42 g H2-COD/g COD removed in the anode, and the bioanode volume-normalized H2 production rate was 0.07-0.1 L/L-d. The biotransformation of the five compounds took place via fermentation followed by exoelectrogenesis. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H2 production were inhibited at an initial substrate concentration of 1200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The MEC H2 production demonstrated in this study is an alternative to the currently used process of reforming natural gas to supply H2 needed to upgrade bio-oils to stable hydrocarbon fuels.

Concentration-related metabolic rate and behavioral thermoregulatory adaptations to serial administrations of nitrous oxide in rats

PubMed Central

2018-01-01

Background Initial administration of ≥60% nitrous oxide (N2O) to rats evokes hypothermia, but after repeated administrations the gas instead evokes hyperthermia. This sign reversal is driven mainly by increased heat production. To determine whether rats will behaviorally oppose or assist the development of hyperthermia, we previously performed thermal gradient testing. Inhalation of N2O at ≥60% causes rats to select cooler ambient temperatures both during initial administrations and during subsequent administrations in which the hyperthermic state exists. Thus, an available behavioral response opposes (but does not completely prevent) the acquired hyperthermia that develops over repeated high-concentration N2O administrations. However, recreational and clinical uses of N2O span a wide range of concentrations. Therefore, we sought to determine the thermoregulatory adaptations to chronic N2O administration over a wide range of concentrations. Methods This study had two phases. In the first phase we adapted rats to twelve 3-h N2O administrations at either 0%, 15%, 30%, 45%, 60% or 75% N2O (n = 12 per group); outcomes were core temperature (via telemetry) and heat production (via respirometry). In the second phase, we used a thermal gradient (range 8°C—38°C) to assess each adapted group’s thermal preference, core temperature and locomotion on a single occasion during N2O inhalation at the assigned concentration. Results In phase 1, repeated N2O administrations led to dose related hyperthermic and hypermetabolic states during inhalation of ≥45% N2O compared to controls (≥ 30% N2O compared to baseline). In phase 2, rats in these groups selected cooler ambient temperatures during N2O inhalation but still developed some hyperthermia. However, a concentration-related increase of locomotion was evident in the gradient, and theoretical calculations and regression analyses both suggest that locomotion contributed to the residual hyperthermia. Conclusions Acquired N2O hyperthermia in rats is remarkably robust, and occurs even despite the availability of ambient temperatures that might fully counter the hyperthermia. Increased locomotion in the gradient may contribute to hyperthermia. Our data are consistent with an allostatic dis-coordination of autonomic and behavioral thermoregulatory mechanisms during drug administration. Our results have implications for research on N2O abuse as well as research on the role of allostasis in drug addiction. PMID:29672605

Microfluidic solvent extraction of poly(vinyl alcohol) droplets: effect of polymer structure on particle and capsule formation.

PubMed

Sharratt, W N; Brooker, A; Robles, E S J; Cabral, J T

2018-04-26

We investigate the formation of poly(vinyl alcohol) microparticles by the selective extraction of aqueous polymer solution droplets, templated by microfluidics and subsequently immersed in a non-solvent bath. The role of polymer molecular mass (18-105 kg mol-1), degree of hydrolysis (88-99%) and thus solubility, and initial solution concentration (0.01-10% w/w) are quantified. Monodisperse droplets with radii ranging from 50 to 500 μm were produced at a flow-focusing junction with carrier phase hexadecane and extracted into ethyl acetate. Solvent exchange and extraction result in droplet shrinkage, demixing, coarsening and phase-inversion, yielding polymer microparticles with well-defined dimensions and internal microstructure. Polymer concentration, varied from below the overlap concentration c* to above the concentrated crossover c**, as estimated by viscosity measurements, was found to have the largest impact on the final particle size and extraction timescale, while polymer mass and hydrolysis played a secondary role. These results are consistent with the observation that the average polymer concentration upon solidification greatly exceeds c**, and that the internal microparticle porosity is largely unchanged. However, reducing the initial polymer concentration to well below c* (approximately 100×) and increasing droplet size yields thin-walled (100's of nm) capsules which controllably crumple upon extraction. The symmetry of the process can be readily broken by imposing extraction conditions at an impermeable surface, yielding large, buckled, cavity morphologies. Based on these results, we establish robust design criteria for polymer capsules and particles, demonstrated here for poly(vinyl alcohol), with well-defined shape, dimensions and internal microstructure.

Practice patterns in neonatal hyperbilirubinemia.

PubMed

Gartner, L M; Herrarias, C T; Sebring, R H

1998-01-01

To determine practice patterns of office-based pediatricians and neonatologists in the treatment of neonatal hyperbilirubinemia in healthy, term newborns during 1992, before the publication of the practice guideline for treatment of neonatal jaundice by the American Academy of Pediatrics (AAP). The survey was undertaken to inform the AAP's Subcommittee on Hyperbilirubinemia on current practices and to aid it in its preparation of the guidelines. It was also anticipated that this survey would serve as a basis for comparison for a second survey to be performed several years after the publication of the practice guidelines. A self-administered questionnaire describing a single case of a jaundiced, breastfed 36-hour-old healthy, full-term infant with a total serum bilirubin concentration of 11.0 mg/dL (188 microM/L) was sent to a random sample of 600 office-based pediatricians and 606 neonatologists who were members of the AAP. The final response rate was 74%. Respondents were asked to answer questions regarding treatment of the case based on their actual practices. Ranges of total serum bilirubin concentration were provided as possible answers to questions on initiation of phototherapy and exchange transfusion, and interruption of breastfeeding. Respondents were also queried about frequency of serum bilirubin testing, locations of phototherapy administration, and factors influencing their therapeutic decisions. Four hundred forty-two office-based pediatricians and 444 neonatologists completed the survey. There was a tendency for neonatologists to initiate both phototherapy and exchange transfusions at lower serum bilirubin concentrations than office-based general pediatricians. At a serum bilirubin of 13 to 19 mg/dL (222 to 325 microM/L), 54% of office-based pediatricians stated they would initiate phototherapy whereas 76% of neonatologists would do so. Forty percent of office-based practitioners said they would perform exchange transfusions at serum bilirubin levels of 20 to 25 mg/dL (342 to 428 microM/L), whereas 60% of neonatologists said they would. Only a small percentage of both office-based practitioners (13%) and neonatologists (16%) indicated they would interrupt breastfeeding at 8 to 13 mg/dL (137 to 222 microM/L); but with each incremental level of serum bilirubin, an increasing proportion of neonatologists would interrupt breastfeeding. Little correlation was found between treatment practices and demographic characteristics except for years in practice; physicians with the fewest years in practice (5 years or less) differed significantly from all other groups of physicians in initiating exchange transfusions at higher serum bilirubin concentrations. The results of this survey indicated a wide range of variation of opinion among both groups of physicians, most likely a reflection of the uncertainty and controversy surrounding these issues. The data may also reflect a possible wide range of "acceptable practice" as opposed to a narrow treatment standard. Office-based practitioners more closely approximated the new 1994 recommendations than neonatologists.

Cost/performance of solar reflective surfaces for parabolic dish concentrators

NASA Technical Reports Server (NTRS)

Bouquet, F.

1980-01-01

Materials for highly reflective surfaces for use in parabolic dish solar concentrators are discussed. Some important factors concerning performance of the mirrors are summarized, and typical costs are treated briefly. Capital investment cost/performance ratios for various materials are computed specifically for the double curvature parabolic concentrators using a mathematical model. The results are given in terms of initial investment cost for reflective surfaces per thermal kilowatt delivered to the receiver cavity for various operating temperatures from 400 to 1400 C. Although second surface glass mirrors are emphasized, first surface, chemically brightened and anodized aluminum surfaces as well as second surface, metallized polymeric films are treated. Conventional glass mirrors have the lowest cost/performance ratios, followed closely by aluminum reflectors. Ranges in the data due to uncertainties in cost and mirror reflectance factors are given.

In Situ Measurements of Aerosol Mass Concentration and Spectral Absorption at Three Location in and Around Mexico City

NASA Astrophysics Data System (ADS)

Chaudhry, Z.; Martins, V.; Li, Z.

2006-12-01

As a result of population growth and increasing industrialization, air pollution in heavily populated urban areas is one of the central environmental problems of the century. As a part of the MILAGRO (Megacity Initiative: Local and Global Research Observations) study, Nuclepore filters were collected in two size ranges (PM10 and PM2.5) at 12 hour intervals at three location in Mexico during March, 2006. Sampling stations were located at the Instituto Mexicano del Petroleo (T0), at the Rancho La Bisnago in the State of Hidalgo (T2) and along the Gulf Coast in Tampico (Tam). Each filter was analyzed for mass concentration, aerosol scattering and absorption efficiencies. Mass concentrations at T0 ranged from 47 to 179 μg/m3 for PM10 with an average concentration of 96 μg/m3, and from 20 to 93 μg/m3 for PM2.5 with an average concentration of 41 μg/m3. Mass concentrations at T2 ranged from 12 to 154 μg/m3 for PM10 with an average concentration of 51 μg/m3, and from 7 to 50 μg/m3 for PM2.5 with an average concentration of 25 μg/m3. Mass concentrations at Tam ranged from 34 to 80 μg/m3 for PM10 with an average concentration of 52 μg/m3, and from 8 to 23 μg/m3 for PM2.5 with an average concentration of 13 μg/m3. While some of the extreme values are likely linked to local emissions, regional air pollution episodes also played important roles. Each of the sampling stations experienced a unique atmospheric condition. The site at T0 was influenced by urban air pollution and dust storms, the site at T2 was significantly less affected by air pollution but more affected by regional dust storms and local dust devils while Tam was influenced by air pollution, dust storms and the natural marine environment. The spectral mass absorption efficiency was measured from 350 to 2500 nm and shows large differences between the absorption properties of soil dust, black carbon, and organic aerosols. The strong spectral differences observed can be related to differences in refractive indices from the several collected species and particle size effects.

In vitro combined effect of co-amoxiclav concentrations achievable in serum after a 2000/125 mg oral dose, and polymorphonuclear neutrophils against strains of Streptococcus pneumoniae exhibiting decreased susceptibility to amoxicillin.

PubMed

Amores, Raquel; Alou, Luis; Giménez, María José; Sevillano, David; Gómez-Lus, María Luisa; Aguilar, Lorenzo; Prieto, José

2004-07-01

The in vitro effect that the presence of components of non-specific immunity (serum plus polymorphonuclear neutrophils) has on the bactericidal activity of co-amoxiclav was explored against Streptococcus pneumoniae strains exhibiting an amoxicillin MIC > or =4 mg/L. Eight penicillin-resistant clinical isolates non-susceptible to co-amoxiclav with MICs of 4 (two strains), 8 (four strains) and 16 mg/L (two strains) were used. Values of MBC were identical to MIC values in all cases. Time-kill curves were performed with co-amoxiclav concentrations achievable in serum after a single oral dose administration of the new 2000/125 mg sustained-release formulation. Results were expressed as percentage of reduction of initial inocula after 3 h incubation. Control curves showed growth with no reduction of initial inocula. Against strains with MIC of 4 and 8 mg/L, the results obtained with the antibiotic alone or with the presence of factors of non-specific immunity were similar, with a weak combined effect due to the intrinsic activity of co-amoxiclav (reductions of initial inocula ranging from 70 to 99.16%). Against strains with MIC of 16 mg/L, the addition of PMN in the presence of serum increased the reduction of bacterial load provided by the aminopenicillin, even at sub-inhibitory concentrations (25.8% versus 51.1% at 0.5 x MIC concentration--8/0.5 mg/L). This combined activity against strains with an amoxicillin MIC of 16 mg/L which decreased the bacterial load may be important in preventing bacterial proliferation within the host and the transmission of resistant clones to others.

Continuous ethanol production from cheese whey fermentation by Candida pseudotropicalis

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

Ghaly, A.E.; El-Taweel, A.A.

1997-12-01

Three pilot-scale continuous mix reactors of 5-L volume each were used to study the effects of retention time (18--42 hours) and initial substrate concentration (50--150 g/L) on the cell yield, lactose consumption, and maximum ethanol concentration during continuous fermentation of cheese whey using the yeast Candida pseudotropicalis. A microaeration rate of 480 mL/min and a nutrient supplement (yeast extract) concentration of 0.1% vol/vol were used. The results indicated that the dissolved oxygen concentration, temperature, cell concentration, lactose utilization rate, and ethanol concentration were affected by hydraulic retention time and initial substrate concentration. The highest cell concentration of 5.46 g/L andmore » the highest ethanol concentration of 57.96 g/L (with a maximum ethanol yield of 99.6% from the theoretical yield) were achieved at the 42-hour hydraulic retention time and the 150 g/L initial substrate concentration, whereas the highest cell yield was observed at the 50 g/L initial substrate concentration and the 36-hour hydraulic retention time. Lactose utilizations of 98, 91, and 83% were obtained with 50, 100, and 150 g/L initial substrate concentrations at the 42-hour hydraulic retention time. A pH control system was found unnecessary.« less

Seasonal differences of corticosterone metabolite concentrations and parasite burden in northern bald ibis (Geronticus eremita): The role of affiliative interactions

PubMed Central

Wascher, Claudia A. F.; Loretto, Matthias-Claudio; Palme, Rupert; Stoewe, Mareike; Kotrschal, Kurt; Frigerio, Didone

2018-01-01

The reproductive season is energetically costly as revealed by elevated glucocorticoid concentrations, constrained immune functions and an increased risk of infections. Social allies and affiliative interactions may buffer physiological stress responses and thereby alleviate associated effects. In the present study, we investigated the seasonal differences of immune reactive corticosterone metabolite concentrations, endoparasite burden (nematode eggs and coccidian oocysts) and affiliative interactions in northern bald ibis (Geronticus eremita), a critically endangered bird. In total, 43 individually marked focal animals from a free-ranging colony were investigated. The analyses included a description of initiated and received affiliative interactions, pair bond status as well as seasonal patterns of hormone and endoparasite levels. During the reproductive season, droppings contained parasite eggs more often and corticosterone metabolite levels were higher as compared to the period after reproduction. The excretion rate of endoparasite products was lower in paired individuals than in unpaired ones, but paired animals exhibited higher corticosterone metabolite concentrations than unpaired individuals. Furthermore, paired individuals initiated affiliative behaviour more frequently than unpaired ones. This suggests that the reproductive season influences the excretion patterns of endoparasite products and corticosterone metabolites and that affiliative interactions between pair partners may positively affect endoparasite burden during periods of elevated glucocorticoid levels. Being embedded in a pair bond may have a positive impact on individual immune system and parasite resistance. PMID:29364951

Dechlorination kinetics of TCE at toxic TCE concentrations: Assessment of different models.

PubMed

Haest, P J; Springael, D; Smolders, E

2010-01-01

The reductive dechlorination of trichloroethene (TCE) in a TCE source zone can be self-inhibited by TCE toxicity. A study was set up to examine the toxicity of TCE in terms of species specific degradation kinetics and microbial growth and to evaluate models that describe this self-inhibition. A batch experiment was performed using the TCE dechlorinating KB-1 culture at initial TCE concentrations ranging from 0.04mM to saturation (8.4mM). Biodegradation activity was highest at 0.3mM TCE and no activity was found at concentrations from 4 to 8mM. Species specific TCE and cis-DCE (cis-dichloroethene) degradation rates and Dehalococcoides numbers were modeled with Monod kinetics combined with either Haldane inhibition or a log-logistic dose-response inhibition on these rates. The log-logistic toxicity model appeared the most appropriate model and predicts that the species specific degradation activities are reduced by a factor 2 at about 1mM TCE, respectively cis-DCE. However, the model showed that the inhibitive effects on the time for TCE to ethene degradation are a complex function of degradation kinetics and the initial cell densities of the dechlorinating species. Our analysis suggests that the self-inhibition on biodegradation cannot be predicted by a single concentration threshold without information on the cell densities.

Biodegradation of di-n-butyl phthalate by bacterial consortium LV-1 enriched from river sludge

PubMed Central

Li, Fangfang; Ruan, Xinling; Song, Jian; Lv, Lv; Chai, Liyuan; Yang, Zhihui; Luo, Lin

2017-01-01

A stable bacterial consortium (LV-1) capable of degrading di-n-butyl phthalate (DBP) was enriched from river sludge. Community analysis revealed that the main families of LV-1 are Brucellaceae (62.78%) and Sinobacteraceae (14.83%), and the main genera of LV-1 are Brucella spp. (62.78%) and Sinobacter spp. (14.83%). The optimal pH and temperature for LV-1 to degrade DBP were pH 6.0 and 30°C, respectively. Inoculum size influenced the degradation ratio when the incubation time was < 24 h. The initial concentration of DBP also influenced the degradation rates of DBP by LV-1, and the degradation rates ranged from 69.0–775.0 mg/l/d in the first 24 h. Degradation of DBP was best fitted by first-order kinetics when the initial concentration was < 300 mg/l. In addition, Cd2+, Cr6+, and Zn2+ inhibited DBP degradation by LV-1 at all considered concentrations, but low concentrations of Pb2+, Cu2+, and Mn2+ enhanced DBP degradation. The main intermediates (mono-ethyl phthalate [MEP], mono-butyl phthalate [MBP], and phthalic acid [PA]) were identified in the DBP degradation process, thus a new biochemical pathway of DBP degradation is proposed. Furthermore, LV-1 also degraded other phthalates with shorter ester chains (DMP, DEP, and PA). PMID:28542471

Synthesis and Properties of Rigid-Rod Benzobisazole Polymers Containing Benzothiazole Pendent Groups

DTIC Science & Technology

1990-11-16

crystalline phase. Poly-p- benzamides containing bulky methyl, nitro or bromo groups affects intermolecular forces to such a large extent that lyotropic...phosphate/m- cresol . Initial attempts in our laboratory involved pendent phenylation via the synthesis of a series of phenylated terphenyl diacids and...range 2.5-9.3 dL/g and exhibited partial solubility (ə%) in m- cresol /strong acid mixtures. Concentrated solutions (>5-) could not be obtained in any

Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

NASA Astrophysics Data System (ADS)

Coleman, Beverly K.; Lunden, Melissa M.; Destaillats, Hugo; Nazaroff, William W.

We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting similar behavior to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established, reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particle sizer (SMPS, 10-400 nm) in every experiment and with an optical particle counter (OPC, 0.1-2.0 μm) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM 1.1) ranged from 10 to >300 μg m -3 and yields ranged from 5% to 37%. Steady-state nucleation rates and SOA mass formation rates were ˜10 cm -3 s -1 and ˜10 μg m -3 min -1, respectively.

Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

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

Coleman, Beverly; Coleman, Beverly K.; Lunden, Melissa M.

2008-01-01

We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting behavior similar to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particlemore » sizer (SMPS, 10 to 400 nm) in every experiment and with an optical particle counter (OPC, 0.1 to 2.0 ?m) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM1.1) ranged from 10 to> 300 mu g m-3 and yields ranged from 5percent to 37percent. Steady-state nucleation rates and SOA mass formation rates were on the order of 10 cm-3 s-1 and 10 mu g m-3 min-1, respectively.« less

High temperature pyrolysis of vinylacetylene

NASA Astrophysics Data System (ADS)

Braun-Unkhoff, M.; Kurz, A.; Frank, P.

1990-07-01

The thermal decomposition of vinylacetylene has been studied behind reflected shock waves in the temperature range 1350-1870 K at total pressures between 1.7 and 7.4 bar. Initial concentrations of the hydrogen in argon ranged between 1 to 300 ppm. The following species were measured: H-atoms by ARAS, C2H2, C4H2 and C4H4 by molecular vuv-absorption. The combination of very low initial concentrations with a sensitive detection technique allowed to perform the experiments under conditions where only very few elementary reaction steps determine the progress of reaction. It was found that C4H4 decomposes simultaneously into different product channels: C4H4→C2H2+C2H2 k1a=3.4ṡ1013 exp(-38820/T) s-1 C4H4+Ar→C4H3+H+Ar k1b=1.1ṡ1020exp(-49990/T) cm3 mol-1 s-1 C4H4→C4H2+H2 k1c=1.3ṡ1015exp(-47670/T) s-1. From variation of the total pressure it has been deduced that reaction pathways R1a and R1c proceed with rates not far from the high-pressure limiting values and that reaction R1b proceeds close to the low-pressure limiting rate constant values.

Sorption of Cr(VI), Cu(II) and Pb(II) by growing and non-growing cells of a bacterial consortium.

PubMed

Sannasi, P; Kader, J; Ismail, B S; Salmijah, S

2006-03-01

This paper reports the sorption of three metallic ions, namely Cr(VI), Cu(II) and Pb(II) in aqueous solution by a consortium culture (CC) comprising an acclimatised mixed bacterial culture collected from point and non-point sources. Metal sorption capability of growing and non-growing cells at initial pH of between 3 and 8 in the 1-100mg/L concentration range were studied based on Q(max) and K(f) values of the Langmuir and linearised Freundlich isotherm models, respectively. Maximal metal loading was generally observed to be dependent on the initial pH. Growing cells displayed significant maximal loading (Q(max)) for Pb(II) (238.09 mg/g) and Cu(II) (178.87 mg/g) at pH 6 and at pH 7 for Cr(VI) (90.91 mg/g) compared to non-growing cells (p < 0.05). At the pH range of 6-8, growing cells showed higher loading capacity compared to non-growing cells i.e. 38-52% for Cr, 17-28% for Cu and 3-17% for Pb. At lower metal concentrations and at more acidic pH (3-4) however, non-growing cells had higher metal loading capacity than growing cells. The metal sorption capacity for both populations were as follows: Pb(II) > Cu(II) > Cr(VI).

Cefazolin pharmacokinetics in cats under surgical conditions.

PubMed

Albarellos, Gabriela A; Montoya, Laura; Passini, Sabrina M; Lupi, Martín P; Lorenzini, Paula M; Landoni, María F

2017-10-01

Objectives The aim of this study was to determine the plasma pharmacokinetic profile, tissue concentrations and urine elimination of cefazolin in cats under surgical conditions after a single intravenous dose of 20 mg/kg. Methods Intravenous cefazolin (20 mg/kg) was administered to nine young mixed-breed cats 30 mins before they underwent surgical procedures (ovariectomy or orchiectomy). After antibiotic administration, samples from blood, some tissues and urine were taken. Cefazolin concentrations were determined in all biological matrices and pharmacokinetic parameters were estimated. Results Initial plasma concentrations were high (C p(0) , 134.80 ± 40.54 µg/ml), with fast and moderately wide distribution (distribution half-life [t ½(d) ] 0.16 ± 0.15 h; volume of distribution at steady state [V (d[ss]) ] 0.29 ± 0.10 l/kg) and rapid elimination (body clearance [Cl B ], 0.21 ± 0.06 l/h/kg; elimination half-life [t ½ ], 1.18 ± 0.27 h; mean residence time 1.42 ± 0.36 h). Thirty to 60 mins after intravenous administration, cefazolin tissue concentrations ranged from 9.24 µg/ml (subcutaneous tissue) to 26.44 µg/ml (ovary). The tissue/plasma concentration ratio ranged from 0.18 (muscle) to 0.58 (ovary). Cefazolin urine concentrations were high with 84.2% of the administered dose being eliminated in the first 6 h postadministration. Conclusions and relevance Cefazolin plasma concentrations remained above a minimum inhibitory concentration of ⩽2 µg/ml up to 4 h in all the studied cats. This suggests that a single intravenous dose of 20 mg/kg cefazolin would be adequate for perioperative prophylactic use in cats.

Design and performance of limestone drains to increase pH and remove metals from acidic mine drainage, Chapter 2

USGS Publications Warehouse

Cravotta,, Charles A.; Watzlaf, George R.

2002-01-01

Data on the construction characteristics and the composition of influent and effluent at 13 underground, limestone-filled drains in Pennsylvania and Maryland are reported to evaluate the design and performance of limestone drains for the attenuation of acidity and dissolved metals in acidic mine drainage. On the basis of the initial mass of limestone, dimensions of the drains, and average flow rates, the initial porosity and average detention time for each drain were computed. Calculated porosity ranged from 0.12 to 0.50 with corresponding detention times at average flow from 1.3 to 33 h. The effectiveness of treatment was dependent on influent chemistry, detention time, and limestone purity. At two sites where influent contained elevated dissolved Al (>5 mg/liter), drain performance declined rapidly; elsewhere the drains consistently produced near-neutral effluent, even when influent contained small concentrations of dissolved Fe^+ (<5 mg/liter). Rates of limestone dissolution computed on the basis of average long-term Ca ion flux normalized by initial mass and purity of limestone at each of the drains ranged from 0.008 to 0.079 year-1. Data for alkalinity concentration and flux during 11-day closed-container tests using an initial mass of 4kg crushed limestone and a solution volume of 2.3 liter yielded dissolution rate constants that were comparable to these long-term field rates. An analytical method is proposed using closed-container test data to evaluate long-term performance (longevity) or to estimate the mass of limestone needed for a limestone treatment. This method condisers flow rate, influent alkalinity, steady-state alkalinity of effluent, and desired effluent alkalinity or detention time at a future time(s) and aplies first-order rate laws for limestone dissolution (continuous) and production of alkalinity (bounded).

Hydrogen speciation in synthetic quartz

USGS Publications Warehouse

Aines, R.D.; Kirby, S.H.; Rossman, G.R.

1984-01-01

The dominant hydrogen impurity in synthetic quartz is molecular H2O. H-OH groups also occur, but there is no direct evidence for the hydrolysis of Si-O-Si bonds to yield Si-OH HO-Si groups. Molecular H2O concentrations in the synthetic quartz crystals studied range from less than 10 to 3,300 ppm (H/Si), and decrease smoothly by up to an order of magnitude with distance away from the seed. OH- concentrations range from 96 to 715 ppm, and rise smoothly with distance away from the seed by up to a factor of three. The observed OH- is probably all associated with cationic impurities, as in natural quartz. Molecular H2O is the dominant initial hydrogen impurity in weak quartz. The hydrolytic weakening of quartz may be caused by the transformation H2O + Si-O-Si ??? 2SiOH, but this may be a transitory change with the SiOH groups recombining to form H2O, and the average SiOH concentration remaining very low. Synthetic quartz is strengthened when the H2O is accumulated into fluid inclusions and cannot react with the quartz framework. ?? 1984 Springer-Verlag.

Uranium removal from aqueous solution by coir pith: equilibrium and kinetic studies.

PubMed

Parab, Harshala; Joshi, Shreeram; Shenoy, Niyoti; Verma, Rakesh; Lali, Arvind; Sudersanan, M

2005-07-01

Basic aspects of uranium adsorption by coir pith have been investigated by batch equilibration. The influence of different experimental parameters such as final solution pH, adsorbent dosage, sorption time, temperature and various concentrations of uranium on uptake were evaluated. Maximum uranium adsorption was observed in the pH range 4.0-6.0. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium. The equilibrium data fitted well to both the equilibrium models in the studied concentration range of uranium (200-800 mg/l) and temperatures (305-336 K). The coir pith exhibited the highest uptake capacity for uranium at 317 K, at the final solution pH value of 4.3 and at the initial uranium concentration of 800 mg/l. The kinetics of the adsorption process followed a second-order adsorption. The adsorbent used proved to be suitable for removal of uranium from aqueous solutions. 0.2 N HCl was effective in uranium desorption. The results indicated that the naturally abundant coir pith of otherwise nuisance value exhibited considerable potential for application in removal of uranium from aqueous solution.

Modeling of ultrasonic degradation of non-volatile organic compounds by Langmuir-type kinetics.

PubMed

Chiha, Mahdi; Merouani, Slimane; Hamdaoui, Oualid; Baup, Stéphane; Gondrexon, Nicolas; Pétrier, Christian

2010-06-01

Sonochemical degradation of phenol (Ph), 4-isopropylphenol (4-IPP) and Rhodamine B (RhB) in aqueous solutions was investigated for a large range of initial concentrations in order to analyze the reaction kinetics. The initial rates of substrate degradation and H(2)O(2) formation as a function of initial concentrations were determined. The obtained results show that the degradation rate increases with increasing initial substrate concentration up to a plateau and that the sonolytic destruction occurs mainly through reactions with hydroxyl radicals in the interfacial region of cavitation bubbles. The rate of H(2)O(2) formation decreases with increasing substrate concentration and reaches a minimum, followed by almost constant production rate for higher substrate concentrations. Sonolytic degradation data were analyzed by the models of Okitsu et al. [K. Okitsu, K. Iwasaki, Y. Yobiko, H. Bandow, R. Nishimura, Y. Maeda, Sonochemical degradation of azo dyes in aqueous solution: a new heterogeneous kinetics model taking into account the local concentration OH radicals and azo dyes, Ultrason. Sonochem. 12 (2005) 255-262.] and Seprone et al. [N. Serpone, R. Terzian, H. Hidaka, E. Pelizzetti, Ultrasonic induced dehalogenation and oxidation of 2-, 3-, and 4-chlorophenol in air-equilibrated aqueous media. Similarities with irradiated semiconductor particulates, J. Phys. Chem. 98 (1994) 2634-2640.] developed on the basis of a Langmuir-type mechanism. The five linearized forms of the Okitsu et al.'s equation as well as the non-linear curve fitting analysis method were discussed. Results show that it is not appropriate to use the coefficient of determination of the linear regression method for comparing the best-fitting. Among the five linear expressions of the Okitsu et al.'s kinetic model, form-2 expression very well represent the degradation data for Ph and 4-IPP. Non-linear curve fitting analysis method was found to be the more appropriate method to determine the model parameters. An excellent representation of the experimental results of sonolytic destruction of RhB was obtained using the Serpone et al.'s model. The Serpone et al.'s model gives a worse fit for the sonolytic degradation data of Ph and 4-IPP. These results indicate that Ph and 4-IPP undergo degradation predominantly at the bubble/solution interface, whereas RhB undergoes degradation at both bubble/solution interface and in the bulk solution. (c) 2010 Elsevier B.V. All rights reserved.

Application of Titration-Based Screening for the Rapid Pilot Testing of High-Throughput Assays.

PubMed

Zhang, Ji-Hu; Kang, Zhao B; Ardayfio, Ophelia; Ho, Pei-i; Smith, Thomas; Wallace, Iain; Bowes, Scott; Hill, W Adam; Auld, Douglas S

2014-06-01

Pilot testing of an assay intended for high-throughput screening (HTS) with small compound sets is a necessary but often time-consuming step in the validation of an assay protocol. When the initial testing concentration is less than optimal, this can involve iterative testing at different concentrations to further evaluate the pilot outcome, which can be even more time-consuming. Quantitative HTS (qHTS) enables flexible and rapid collection of assay performance statistics, hits at different concentrations, and concentration-response curves in a single experiment. Here we describe the qHTS process for pilot testing in which eight-point concentration-response curves are produced using an interplate asymmetric dilution protocol in which the first four concentrations are used to represent the range of typical HTS screening concentrations and the last four concentrations are added for robust curve fitting to determine potency/efficacy values. We also describe how these data can be analyzed to predict the frequency of false-positives, false-negatives, hit rates, and confirmation rates for the HTS process as a function of screening concentration. By taking into account the compound pharmacology, this pilot-testing paradigm enables rapid assessment of the assay performance and choosing the optimal concentration for the large-scale HTS in one experiment. © 2013 Society for Laboratory Automation and Screening.

Temperature Rise and Allowable Carbon Emissions for the RCP2.6 Scenario

NASA Astrophysics Data System (ADS)

Tachiiri, K.; Hargreaves, J. C.; Annan, J. D.; Huntingford, C.; Kawamiya, M.

2012-12-01

Climate research centres are running Earth System Models (ESMs) forced by Representative Concentration Pathway (RCP) scenarios. While these GCM studies increase process based knowledge, the number of simulations is small, making it difficult to interpret the resulting distribution of responses in a probabilistic way. We use a probabilistic framework to estimate the range of future temperature change and allowable emissions for a low mitigation CO2 concentration pathway RCP 2.6. Uncertainty is initially estimated by allowing modelled equilibrium climate sensitivity, aerosol forcing and intrinsic physical and biogeochemical processes to vary within widely accepted ranges. Results are then further constrained by extensive use of contemporary measurements. Despite this, the resulting range of temperatures for RCP 2.6 remains large. The predicted peak global temperature increase, reached around 2100, from pre-industrial is 0.8 - 1.9 K and 1.0 - 1.9 K (95% range) for the unconstrained and the constrained cases, respectively. Allowable emissions at the time of peak emission period is projected as 6.0 - 10.8 PgC yr-1 and 7.4 - 10.2 PgC yr-1 for each case. After year 2100, negative net emissions are required with a probability of some 84 %, and related uncertainty in cumulative emissions is large.

Fluid Mechanical Properties of Silkworm Fibroin Solutions

NASA Astrophysics Data System (ADS)

Matsumoto, Akira

2005-11-01

The aqueous solution behavior of silk fibroin is of interest due to the assembly and processing of this protein related to the spinning of protein fibers that exhibit remarkable mechanical properties. To gain insight into the origins of this functional feature, it is desired to determine how the protein behaves under a range of solution conditions. Pure fibroin at different concentrations in water was studied for surface tension, as a measure of surfactancy. In addition, shear induced changes on these solutions in terms of structure and morphology was also determined. Fibroin solutions exhibited shear rate-sensitive viscosity changes and precipitated at a critical shear rate where a dramatic increase of 75-150% of the initial value was observed along with a decrease in viscosity. In surface tension measurements, critical micelle concentrations were in the range of 3-4% w/v. The influence of additional factors, such as sericin protein, divalent and monovalent cations, and pH on the solution behavior in relation to structural and morphological features will also be described.

Drying paint: from micro-scale dynamics to mechanical instabilities

NASA Astrophysics Data System (ADS)

Goehring, Lucas; Li, Joaquim; Kiatkirakajorn, Pree-Cha

2017-04-01

Charged colloidal dispersions make up the basis of a broad range of industrial and commercial products, from paints to coatings and additives in cosmetics. During drying, an initially liquid dispersion of such particles is slowly concentrated into a solid, displaying a range of mechanical instabilities in response to highly variable internal pressures. Here we summarize the current appreciation of this process by pairing an advection-diffusion model of particle motion with a Poisson-Boltzmann cell model of inter-particle interactions, to predict the concentration gradients in a drying colloidal film. We then test these predictions with osmotic compression experiments on colloidal silica, and small-angle X-ray scattering experiments on silica dispersions drying in Hele-Shaw cells. Finally, we use the details of the microscopic physics at play in these dispersions to explore how two macroscopic mechanical instabilities-shear-banding and fracture-can be controlled. This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications.'

Microbial ranking of porous packaging materials (exposure chamber method), ASTM method: collaborative study.

PubMed

Placencia, A M; Peeler, J T

1999-01-01

A collaborative study involving 11 laboratories was conducted to measure the microbial barrier effectiveness of porous medical packaging. Two randomly cut samples from each of 6 commercially available porous materials and one positive and one negative control were tested by one operator in each of 11 laboratories. Microbial barrier effectiveness was measured in terms of logarithm reduction value (LRV), which reflects the log10 microbial penetration of the material being tested. The logarithm of the final concentration is subtracted from that of the initial concentration to obtain the LRV. Thus the higher the LRV, the better the barrier. Repeatability standard deviations ranged from 6.42 to 16.40; reproducibility standard deviations ranged from 15.50 to 22.70. Materials B(53), C(50), D(CT), and E(45MF) differ significantly from the positive control. The microbial ranking of porous packaging materials (exposure chamber method), ASTM method, has been adopted First Action by AOAC INTERNATIONAL.

WIND MEASUREMENTS WITH HIGH-ENERGY DOPPLER LIDAR

NASA Technical Reports Server (NTRS)

Koch, Grady J.; Kavaya, Michael J.; Barnes, Bruce W.; Beyon, Jeffrey Y.; Petros, Mulugeta; Jirong, Yu; Amzajerdian, Farzin; Slingh, Upendra N.

2006-01-01

Coherent lidars at 2-micron wavelengths from holmium or thulium solid-state lasers have been in use to measure wind for applications in meteorology, aircraft wake vortex tracking, and turbulence detection [1,2,3] These field-deployed lidars, however, have generally been of a pulse energy of a few millijoules, limiting their range capability or restricting operation to regions of high aerosol concentration such as the atmospheric boundary layer. Technology improvements in the form of high-energy pulsed lasers, low noise detectors, and high optical quality telescopes are being evaluated to make wind measurements to long ranges or low aerosol concentrations. This research is aimed at developing lidar technology for satellite-based observation of wind on a global scale. The VALIDAR project was initiated to demonstrate a high pulse energy coherent Doppler lidar. VALIDAR gets its name from the concept of validation lidar, in that it can serve as a calibration and validation source for future airborne and spaceborne lidar missions. VALIDAR is housed within a mobile trailer for field measurements.

Parameters affecting the inhibition of Candida albicans GDH 2023 and GRI 2773 blastospore viability by purified synthetic salivary histidine-rich polypeptides.

PubMed

Santarpia, R P; Cho, M I; Pollock, J J

1990-08-01

Purified synthetic salivary histidine-rich polypeptides, HRPs 2, 3, 4, 5, and 6, were observed to inhibit Candida albicans blastospore viability at yeast cell concentrations ranging from 10(2) to greater than 10(6) colony forming units per ml. Among the HRPs, HRP-4 was the best inhibitor with significant killing activity noted at a peptide concentration of 0.5 microgram per ml. Antifungal potency under growth conditions was observed to be dependent upon pH. In contrast, killing did not vary throughout the pH range tested under non-growth conditions. Electron microscopy results demonstrated HRP damage at pH 5 which appeared to be initiated at the membrane. At pH 7.4, micrographs revealed clear evidence of intracellular destruction suggesting more extensive damage at neutral as compared to acidic pH. These results suggest that within the changing realm of the oral cavity, the HRPs would be expected to be potent killers of C. albicans.

A comparative study of accumulation rates derived by He and Th isotope analysis of marine sediments

NASA Astrophysics Data System (ADS)

Marcantonio, Franco; Kumar, Niraj; Stute, Martin; Anderson, Robert F.; Seidl, Michele A.; Schlosser, Peter; Mix, Alan

1995-07-01

We present a detailed down-core analysis of helium isotope ratios and concentrations for bulk sediments from the central Equatorial Pacific that span the last two glacial-interglacial cycles. Measured 3He/4He ratios range from 1.0 × 10 -5 to 2.1 × 10 -4, or 7.4 to 149 times the atmospheric ratio. The 3He from interplanetary dust particles (IDPs) constitutes virtually all of the 3He measured within the sediment. Because carbonate accumulation rates are high in the Equatorial Pacific, the measured 3He concentrations are lower than have been measured elsewhere, and range from 4.7 × 10 -13 to 3.0 × 10 -12 cm 3STP · g -1. If the cosmic dust 3He-flux is constant with time, sediment mass accumulation rates can be determined from the 3He concentration in sediments. The excess 230Th technique is an entirely independent method for calculating sediment mass accumulation rates because its source is in-situ decay of 234U in seawater. To first order, initial excess 230Th activities correlate with 3He concentrations within this core. Based on the 230Th results, we estimate the 3He-flux to the Earth's surface as (9.6 ± 2.0) × 10 -16 cm 3STP · cm -2 · a -1. If this flux has remained constant over extended periods of time, it can be used to determine sediment accumulation rates beyond the 230Th range (300,000 yr).

Effect of benzene, toluene, ethylbenzene, and p-xylene (BTEX) mixture on biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) by pure culture UC1.

PubMed

Pruden, Amy; Suidan, Makram

2004-08-01

The effect of a BTEX mixture on the biodegradation of methyl tert-butyl ether (MTBE) and its degradation intermediate, tert-butyl alcohol (TBA) was investigated in the pure bacterial culture UC1, which has been identified to be a strain of the known MTBE-degrader PM1 based on greater than 99% 16S rDNA similarity. Several degradation studies were carried out on UC1 at three initial concentration levels of MTBE or TBA: 6-7; 15-17; and 40-45 mg/l, both with and without BTEX present cumulatively at about half of the MTBE or TBA molar mass in the system. The BTEX mixture was observed not to affect either the rate or the degradation lag period of MTBE or TBA degradation, except that the TBA degradation rate actually increased when BTEX was present initially in the highest concentration studies. When serving as the sole substrate, the MTBE degradation rate ranged from 48 +/- 1.2 to 200 +/- 7.0 mg(MTBE)/g(dw) h, and the TBA degradation rate from 140 +/- 18 to 530 +/- 70 mg(TBA)/g(dw) h. When present with BTEX, MTBE and TBA rates ranged from 46 +/- 2.2 to 210 +/- 14 and 170 +/- 28 to 780 +/- 43 mg(TBA)/g(dw) h, respectively. In studies where varying concentrations of TBA were present with 5 mg/l MTBE, both compounds were degraded simultaneously with no obvious preference for either substrate. In the highest concentration study of TBA with 5 mg/l MTBE, BTEX was also observed to increase the ultimate rate of TBA degradation. In addition to exploring the affect of BTEX, this study also provides general insight into the metabolism of MTBE and TBA by pure culture UC1.

Kinetic model of excess activated sludge thermohydrolysis.

PubMed

Imbierowicz, Mirosław; Chacuk, Andrzej

2012-11-01

Thermal hydrolysis of excess activated sludge suspensions was carried at temperatures ranging from 423 K to 523 K and under pressure 0.2-4.0 MPa. Changes of total organic carbon (TOC) concentration in a solid and liquid phase were measured during these studies. At the temperature 423 K, after 2 h of the process, TOC concentration in the reaction mixture decreased by 15-18% of the initial value. At 473 K total organic carbon removal from activated sludge suspension increased to 30%. It was also found that the solubilisation of particulate organic matter strongly depended on the process temperature. At 423 K the transfer of TOC from solid particles into liquid phase after 1 h of the process reached 25% of the initial value, however, at the temperature of 523 K the conversion degree of 'solid' TOC attained 50% just after 15 min of the process. In the article a lumped kinetic model of the process of activated sludge thermohydrolysis has been proposed. It was assumed that during heating of the activated sludge suspension to a temperature in the range of 423-523 K two parallel reactions occurred. One, connected with thermal destruction of activated sludge particles, caused solubilisation of organic carbon and an increase of dissolved organic carbon concentration in the liquid phase (hydrolysate). The parallel reaction led to a new kind of unsolvable solid phase, which was further decomposed into gaseous products (CO(2)). The collected experimental data were used to identify unknown parameters of the model, i.e. activation energies and pre-exponential factors of elementary reactions. The mathematical model of activated sludge thermohydrolysis appropriately describes the kinetics of reactions occurring in the studied system. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simultaneous removal of SO2 and NOx from flue gas by wet scrubbing using a urea solution.

PubMed

Li, Ge; Wang, Baodong; Xu, Wayne Qiang; Li, Yonglong; Han, Yifan; Sun, Qi

2018-03-27

Nitrogen oxides (NO x ) and sulfur dioxide (SO 2 ) are major air pollutants, so simultaneously removing them from gases emitted during fossil fuel combustion in stationary systems is important. Wet denitrification using urea is used for a wide range of systems. Additives have strong effects on wet denitrification using urea, and different mechanisms are involved and different effects found using different additives. In this study, the effects of different additives, initial urea concentrations, reaction temperatures, initial pH values, gas flow rates, and reaction times on the simultaneous desulfurization and denitrification efficiencies achieved using wet denitrification using urea were studied in single factor experiment. The optimum reaction conditions for desulfurization and denitrification were found. Desulfurization and denitrification efficiencies of 97.5% and 96.3%, respectively, were achieved at a KMnO 4 concentration 5 mmol/L, a reaction temperature of 70°C, initial urea solution pH 8, a urea concentration of 9%, and a gas flow rate of 40 L/h. The concentrations of the desulfurization and denitrification reaction products in the solution were determined. NO x was mainly transformed into N 2 , and the [Formula: see text] and [Formula: see text] concentrations in the solution became very low. The reactions involved in SO 2 and NO x removal using urea were analyzed from the thermodynamic viewpoint. Increasing the temperature was not conducive to the reactions but increased the rate constant, so an optimum temperature was determined. The simultaneous desulfurization and denitrification kinetics were calculated. The urea consumption and [Formula: see text], [Formula: see text], and [Formula: see text] generation reactions were all zero order. The [Formula: see text] generation rate was greater than the [Formula: see text] generation rate. The simultaneous desulfurization and denitrification process and mechanism were studied. The results provide reference data for performing flue gas desulfurization and denitrification in factories.

The influence of initial atomized droplet size on residual particle size from pressurized metered dose inhalers.

PubMed

Sheth, Poonam; Stein, Stephen W; Myrdal, Paul B

2013-10-15

Pressurized metered dose inhalers (pMDIs) are widely used for the treatment of diseases of the lung, including asthma and chronic obstructive pulmonary disease. The mass median aerodynamic diameter of the residual particles (MMADR) delivered from a pMDI plays a key role in determining the amount and location of drug deposition in the lung and thereby the efficacy of the inhaler. The mass median diameter of the initial droplets (MMDI), upon atomization of a formulation, is a significant factor influencing the final particle size. The purpose of this study was to evaluate the extent that MMDI and initial droplet geometric standard deviation (GSD) influence the residual aerodynamic particle size distribution (APSDR) of solution and suspension formulations. From 48 solution pMDI configurations with varying ethanol concentrations, valve sizes and actuator orifice diameters, it was experimentally found that the effective MMDI ranged from 7.8 to 13.3 μm. Subsequently, computational methods were utilized to determine the influence of MMDI on MMADR, by modulating the MMDI for solution and suspension pMDIs. For solution HFA-134a formulations of 0.5% drug in 10% ethanol, varying the MMDI from 7.5 to 13.5 μm increased the MMADR from 1.4 to 2.5 μm. For a suspension formulation with a representative particle size distribution of micronized drug (MMAD=2.5 μm, GSD=1.8), the same increase in MMDI resulted in an increase in the MMADR from 2.7 to only 3.3 μm. Hence, the same increase in MMDI resulted in a 79% increase in MMADR for the solution formulation compared to only a 22% increase for the suspension formulation. Similar trends were obtained for a range of drug concentrations and input micronized drug sizes. Thus, APSDR is more sensitive to changes in MMDI for solution formulations than suspension formulations; however, there are situations in which hypothetically small micronized drug in suspension (e.g. 500 nm MMAD) could resemble trends observed for solution formulations. Furthermore, the relationship between APSDR and drug concentration and MMDI is predictable for solution pMDIs, but this is not as straightforward for suspension formulations. In addition, the MMADR was relatively insensitive to changes in initial droplet GSD (from 1.6 to 2.0) and the solution and suspension pMDI residual particle GSDs were essentially identical to the initial droplet GSDs. Copyright © 2013 Elsevier B.V. All rights reserved.

Postmortem distribution of guaifenesin concentrations reveals a lack of potential for redistribution.

PubMed

McIntyre, Iain M; Navarrete, Aylmer; Mena, Othon

2014-12-01

Therapeutic (or non-toxic) postmortem guaifenesin blood and liver concentrations have not been previously described. Peripheral blood guaifenesin concentrations were compared to central blood and liver concentrations in eight medical examiner cases. Specimens were initially screened for alcohol and simple volatiles, drugs of abuse, alkaline, and acid/neutral drugs. Guaifenesin, when detected by the acid/neutral drug screen, was subsequently confirmed and quantified by a high performance liquid chromatography procedure. Data suggest that postmortem guaifenesin peripheral blood concentrations may be considered non-toxic to at least 5.4mg/L with liver concentrations to at least 7.0mg/kg. Overall, guaifenesin concentrations ranged from 1.9 to 40mg/L in peripheral blood, 2.2-150mg/L in central blood, and 2.6-36mg/kg in liver. The median guaifenesin central blood to peripheral blood ratio was 1.1 (N=8). Similarly, liver to peripheral blood ratios showed a median value of 0.9L/kg (N=5). Given that a liver to peripheral blood ratio less than 5L/kg is consistent with little to no propensity for postmortem redistribution, these data suggest that guaifenesin is not prone to substantial postmortem redistribution. Published by Elsevier Ireland Ltd.

Formulation of wax oxybenzone microparticles using a factorial approach.

PubMed

Gomaa, Y A; Darwish, I A; Boraei, N A; El-Khordagui, L K

2010-01-01

Oxybenzone wax microparticles (MPs) were prepared by the hydrophobic congealable disperse phase method. The formulation of oxybenzone-loaded MPs was optimized using a 2⁴ experimental design. Factorial analysis indicated that the main MP characteristics were influenced by initial drug loading, emulsification speed, emulsifier concentration and hydrophilic-lipophilic balance. MPs were spherical with 50.5–88.1 μm size range, 17.8–38.9 drug content in mg/100 mg MPs and 33.1–87.2% oxybenzone release in 1 h. A wide range of sunscreen delivery systems suitable for different formulation purposes were generated which may contribute to the advanced formulation of sunscreen products with improved performance.

Anomalous transport in cellular flows: The role of initial conditions and aging

NASA Astrophysics Data System (ADS)

Pöschke, Patrick; Sokolov, Igor M.; Nepomnyashchy, Alexander A.; Zaks, Michael A.

2016-09-01

We consider the diffusion-advection problem in two simple cellular flow models (often invoked as examples of subdiffusive tracer motion) and concentrate on the intermediate time range, in which the tracer motion indeed may show subdiffusion. We perform extensive numerical simulations of the systems under different initial conditions and show that the pure intermediate-time subdiffusion regime is only evident when the particles start at the border between different cells, i.e., at the separatrix, and is less pronounced or absent for other initial conditions. The motion moreover shows quite peculiar aging properties, which are also mirrored in the behavior of the time-averaged mean squared displacement for single trajectories. This kind of behavior is due to the complex motion of tracers trapped inside the cell and is absent in classical models based on continuous-time random walks with no dynamics in the trapped state.

Association between outcome and changes in plasma lactate concentration during presurgical treatment in dogs with gastric dilatation-volvulus: 64 cases (2002-2008).

PubMed

Zacher, Laurie A; Berg, John; Shaw, Scott P; Kudej, Raymond K

2010-04-15

To determine whether changes in presurgical plasma lactate concentration (before and after initial fluid resuscitation and gastric decompression) were associated with short-term outcome for dogs with gastric dilatation-volvulus (GDV). Retrospective case series. 64 dogs. Medical records were reviewed, and signalment, history, resuscitative treatments, serial presurgical lactate concentrations, surgical findings, and short-term outcome were obtained for dogs with confirmed GDV. 36 of 40 (90%) dogs with an initial lactate concentration 9.0 mmol/L). Within HIL dogs, there was no difference in mean +/- SD initial lactate concentration between survivors and nonsurvivors (10.6 +/- 2.3 mmol/L vs 11.2 +/- 2.3 mmol/L, respectively); however, there were significant differences in post-treatment lactate concentration, absolute change in lactate concentration, and percentage change in lactate concentration following resuscitative treatment. By use of optimal cutoff values within HIL dogs, survival rates for dogs with final lactate concentration > 6.4 mmol/L (23%), absolute change in lactate concentration 4 mmol/L (86%), or percentage change in lactate concentration > 42.5% (100%). Calculating changes in plasma lactate concentration following initial treatment in dogs with GDV may assist in determining prognosis and identifying patients that require more aggressive treatment.

Surface contamination artificially elevates initial sweat mineral concentrations

USDA-ARS?s Scientific Manuscript database

During exercise in the heat, sweat is initially concentrated in minerals, but serial sweat samples appear more dilute. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. PURPOSE: To simultaneously sample mineral concentrations in transdermal fluid (T...

Inhomogeneous growth of fluctuations of concentration of inertial particles in channel turbulence

NASA Astrophysics Data System (ADS)

Fouxon, Itzhak; Schmidt, Lukas; Ditlevsen, Peter; van Reeuwijk, Maarten; Holzner, Markus

2018-06-01

We study the growth of concentration fluctuations of weakly inertial particles in the turbulent channel flow starting with a smooth initial distribution. The steady-state concentration is singular and multifractal so the growth describes the increasingly rugged structure of the distribution. We demonstrate that inhomogeneity influences the growth of concentration fluctuations profoundly. For homogeneous turbulence the growth is exponential and is fully determined by Kolmogorov scale eddies.We derive lognormality of the statistics in this case. The growth exponents of the moments are proportional to the sum of Lyapunov exponents, which is quadratic in the small inertia of the particles. In contrast, for inhomogeneous turbulence the growth is linear in inertia. It involves correlations of inertial range and viscous scale eddies that turn the growth into a stretched exponential law with exponent three halves. We demonstrate using direct numerical simulations that the resulting growth rate can differ by orders of magnitude over channel height. This strong variation might have relevance in the planetary boundary layer.

Gas1 extends the range of Hedgehog action by facilitating its signaling

PubMed Central

Martinelli, David C.; Fan, Chen-Ming

2007-01-01

Cellular signaling initiated by Hedgehog binding to Patched1 has profound importance in mammalian embryogenesis, genetic disease, and cancer. Hedgehog acts as a morphogen to specify distinctive cell fates using different concentration thresholds, but our knowledge of how the concentration gradient is interpreted into the activity gradient is incomplete. The membrane protein Growth Arrest-Specific Gene 1 (GAS1) was thought to be a negative regulator of the Hedgehog concentration gradient. Here, we report unexpected genetic evidence that Gas1 positively regulates Hedgehog signaling in multiple developmental contexts, an effect particularly noticeable at regions where Hedgehog acts at low concentration. Using a combination of in vitro cell culture and in ovo electroporation assays, we demonstrate that GAS1 acts cooperatively with Patched1 for Hedgehog binding and enhances signaling activity in a cell-autonomous manner. Our data support a model in which GAS1 helps transform the Hedgehog protein gradient into the observed activity gradient. We propose that Gas1 is an evolutionarily novel, vertebrate-specific Hedgehog pathway regulator. PMID:17504940

Growth Recovery of Lemna gibba and Lemna minor Following a 7-Day Exposure to the Herbicide Diuron.

PubMed

Burns, Mitchell; Hanson, Mark L; Prosser, Ryan S; Crossan, Angus N; Kennedy, Ivan R

2015-08-01

In agricultural catchments, aquatic ecosystems can experience a pulse exposure to pesticides. Following such exposure, non-target organisms that are not extirpated may recover. This paper investigates the potential of two duckweed species (Lemna minor and Lemna gibba) to recover from a 7-day exposure to different concentrations (0.4-208 µg L(-1)) of the herbicide diuron. There was significant inhibition in the growth and biomass after the initial 7-day exposure (e.g. frond number EC50=59.2 and 52.2 µg L(-1) for L. minor and L. gibba, respectively). Following transfer to clean media, recovery (the highest concentration yielding no significant difference in the effect endpoint from the control) was observed for all effects endpoints at concentrations ranging 60-111 µg L(-1) for L. minor and 60-208 µg L(-1) for L. gibba. These results suggest that recovery is possible for primary producers at environmentally relevant concentrations considered significant in ecological risk assessment.

Treatment of chromium contaminated soil using bioremediation

NASA Astrophysics Data System (ADS)

Purwanti, Ipung Fitri; Putri, Tesya Paramita; Kurniawan, Setyo Budi

2017-11-01

Chromium contamination in soil occurs due to the disposal of chromium industrial wastewater or sludge that excess the quality standard. Chromium concentration in soil is ranged between 1 to 300 mg/kg while the maximum health standard is 2.5 mg/kg. Bioremediation is one of technology that could be used for remediating heavy metal contamination in soil. Bacteria have an ability to remove heavy metal from soil. One bacteria species that capable to remove chromium from soil is Bacillus subtilis. The aim of this research was to know the chromium removal percentage in contaminated soil by Bacillus subtilis. Artificial chromium contaminated soil was used by mixing 425gram sand and chromium trichloride solution. Concentration of chromium added into the spiked soil were 50, 75, and 100 mg/L. During 14 days, pH, soil temperature and soil moisture were tested. Initial and final number of bacterial colony and chromium concentration analysed. The result showed that the highest percentage of chromium removal was 11% at a chromium concentration of 75 mg/L

Dietary Management of Hyperthyroidism in a Dog.

PubMed

Looney, Andrea; Wakshlag, Joseph

An 8 yr old female spayed golden retriever presented for a routine exam during which ventral cervical soft tissue masses were identified. History included weight loss, increased activity and appetite, gagging, and occasional diarrhea. Exam findings included a body condition score of 4/9 and palpable ventral cervical nodules. A serum thyroxine (T4) value was 8.0 ug/dL (normal = 0.8-3.5ug/dL). Doppler systolic blood pressure readings ranged from 200-210 mmHg (normal systolic blood pressure <150 mmHg). The diagnosis was hyperthyroidism due to active thyroid masses. Due to financial constraints, the owner elected conservative management. Initial treatment with methimazole resulted in a decreased T4 value of 5.0 ug/dL at approximately 4 mo after initiation of treatment. A commercially available iodine-restricted feline diet was fed and this resulted in further reduction in serum T4 levels, improved sleeping cycles, reduced anxiety, and reduced systolic blood pressure. A temporary suspension of iodine-restricted feline diet for 2 mo resulted in increases in serum T4 concentrations, which, subsequently, decreased with re-introduction of the diet. Roughly 10 mo after initiation of the therapeutic diet and 16 mo after intial diagnosis, the dog remains relatively normal clinically despite active growing cervical masses with T4 concentration of 2.3 ug/dL.

Evaluation of predictors for the diagnosis of hyperthyroidism in cats.

PubMed

Wakeling, Jennifer; Elliott, Jonathan; Syme, Harriet

2011-01-01

In humans, subclinical hyperthyroidism is diagnosed when serum thyroid hormone concentrations are within the reference range but thyroid stimulating hormone (TSH) concentration is subnormal. In a previous study, a higher prevalence of thyroid nodular disease was found in euthyroid geriatric cats with undetectable TSH (<0.03 ng/mL) compared to those with detectable TSH concentrations, suggesting subclinical hyperthyroidism might also exist in cats. Euthyroid cats with undetectable TSH concentrations have subclinical hyperthyroidism and may subsequently develop overt signs of hyperthyroidism. One-hundred four client-owned cats. In this prospective cohort study, euthyroid geriatric (≥ 9 years) cats were recruited during routine health checks. Plasma biochemistry was performed at baseline and every 6 months thereafter. Total thyroxine and TSH concentrations were determined annually. Short-term follow-up data (within 14 months of recruitment) were used to detect variables at entry that were predictive of the diagnosis of hyperthyroidism, using univariable analysis followed by multivariable logistic regression analysis. Log rank analysis was used to test the association of initial TSH concentration with diagnosis of hyperthyroidism during the total available follow-up. Median (range) follow-up was 26 (0-54) months and annual incidence of hyperthyroidism during the study was 7.4%. Cats that became hyperthyroid within 14 months had higher ALKP activity (P = 0.02) and higher prevalence of goiter (P = .03) at baseline than controls. Cats with undetectable TSH at baseline (29/104; 28%) were significantly (P < .001) more likely to be diagnosed with hyperthyroidism. However, not all cats with undetectable TSH became hyperthyroid during the study. Copyright © 2011 by the American College of Veterinary Internal Medicine.

Rapid measurement of perchlorate in polar ice cores down to sub-ng L(-1) levels without pre-concentration.

PubMed

Peterson, Kari; Cole-Dai, Jihong; Brandis, Derek; Cox, Thomas; Splett, Scott

2015-10-01

An ion chromatography-electrospray ionization-tandem mass spectrometry (IC-ESI-MS/MS) method has been developed for rapid and accurate measurement of perchlorate in polar snow and ice core samples in which perchlorate concentrations are expected to be as low as 0.1 ng L(-1). Separation of perchlorate from major inorganic species in snow is achieved with an ion chromatography system interfaced to an AB SCIEX triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. Under optimized conditions, the limit of detection and lower limit of quantification without pre-concentration have been determined to be 0.1 and 0.3 ng L(-1), respectively, with a linear dynamic range of 0.3-10.0 ng L(-1) in routine measurement. These represent improvements over previously reported methods using similar analytical techniques. The improved method allows fast, accurate, and reproducible perchlorate quantification down to the sub-ng L(-1) level and will facilitate perchlorate measurement in the study of natural perchlorate production with polar ice cores in which perchlorate concentrations are anticipated to vary in the low and sub-ng L(-1) range. Initial measurements of perchlorate in ice core samples from central Greenland show that typical perchlorate concentrations in snow dated prior to the Industrial Revolution are about 0.8 ng L(-1), while perchlorate concentrations are significantly higher in recent (post-1980) snow, suggesting that anthropogenic sources are a significant contributor to perchlorate in the current environment.

CPTC and NIST-sponsored Yeast Reference Material Now Publicly Available | Office of Cancer Clinical Proteomics Research

Cancer.gov

The yeast protein extract (RM8323) developed by National Institute of Standards and Technology (NIST) under the auspices of NCI's CPTC initiative is currently available to the public at https://www-s.nist.gov/srmors/view_detail.cfm?srm=8323. The yeast proteome offers researchers a unique biological reference material. RM8323 is the most extensively characterized complex biological proteome and the only one associated with several large-scale studies to estimate protein abundance across a wide concentration range.

Optical, microphysical, mass and geometrical properties of aged volcanic particles observed over Athens, Greece, during the Eyjafjallajökull eruption in April 2010 through synergy of Raman lidar and sunphotometer measurements

NASA Astrophysics Data System (ADS)

Kokkalis, P.; Papayannis, A.; Amiridis, V.; Mamouri, R. E.; Veselovskii, I.; Kolgotin, A.; Tsaknakis, G.; Kristiansen, N. I.; Stohl, A.; Mona, L.

2013-09-01

Vertical profiles of the optical (extinction and backscatter coefficients, lidar ratio and Ångström exponent), microphysical (mean effective radius, mean refractive index, mean number concentration) and geometrical properties as well as the mass concentration of volcanic particles from the Eyjafjallajökull eruption were retrieved at selected heights over Athens, Greece, using multi-wavelength Raman lidar measurements performed during the period 21-24 April 2010. Aerosol Robotic Network (AERONET) particulate columnar measurements along with inversion schemes were initialized together with lidar observations to deliver the aforementioned products. The well-known FLEXPART (FLEXible PARTicle dispersion model) model used for volcanic dispersion simulations is initiated as well in order to estimate the horizontal and vertical distribution of volcanic particles. Compared with the lidar measurements within the planetary boundary layer over Athens, FLEXPART proved to be a useful tool for determining the state of mixing of ash with other, locally emitted aerosol types. The major findings presented in our work concern the identification of volcanic particles layers in the form of filaments after 7-day transport from the volcanic source (approximately 4000 km away from our site) from the surface and up to 10 km according to the lidar measurements. Mean hourly averaged lidar signals indicated that the layer thickness of volcanic particles ranged between 1.5 and 2.2 km. The corresponding aerosol optical depth was found to vary from 0.01 to 0.18 at 355 nm and from 0.02 up to 0.17 at 532 nm. Furthermore, the corresponding lidar ratios (S) ranged between 60 and 80 sr at 355 nm and 44 and 88 sr at 532 nm. The mean effective radius of the volcanic particles estimated by applying inversion scheme to the lidar data found to vary within the range 0.13-0.38 μm and the refractive index ranged from 1.39+0.009i to 1.48+0.006i. This high variability is most probably attributed to the mixing of aged volcanic particles with other aerosol types of local origin. Finally, the LIRIC (LIdar/Radiometer Inversion Code) lidar/sunphotometric combined inversion algorithm has been applied in order to retrieve particle concentrations. These have been compared with FLEXPART simulations of the vertical distribution of ash showing good agreement concerning not only the geometrical properties of the volcanic particles layers but also the particles mass concentration.

Copper in the intake and discharge zones of the Surry and Salem Nuclear Power Stations

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

Harrison, F.L.; Bishop, D.J.; Rice, D.W. Jr.

Copper concentrations were measured in the soluble and particulate fractions of water samples and bedload sediments collected in intake and discharge areas of the Surry and Salem Nuclear Power Stations during normal operations. Additional samples of water and suspended particles were collected during startup of Unit 2 at the Salem Power Station. In water samples collected from Surry, total copper ranged from 6.5 to 24.7 and labile copper from 0.5 to 2.9 ..mu..g/L; in those from Salem, total copper ranged from 6.7 to 10.6 and labile from 0.9 to 3.8 ..mu..g/L. At both sites the highest total copper concentration wasmore » measured in January 1979 during a period of high runoff. In general, differences between influent and effluent waters were small; the maximum was 4.2 ..mu..g Cu/L. Copper concentration in the water during startup of Unit 2 of Salem was high initially (>2500 ..mu..g Cu/L) but was almost entirely in the particulate fraction; labile copper was only 0.6 ..mu..g/L. The apparent complexing capacity (ACC) of the waters from Surry ranged from 6 to 40 and those from Salem from 5 to 60 ..mu..g Cu/L. Ranges in dissolved organic carbon were smaller, 2.9 to 5.1 and 2.2 to 5.0 mg C/L for Surry and Salem, respectively, and showed no relationship with ACC. Ultrafiltration of discharge waters indicated that, in most samples, the largest fraction of copper in the untreated water was in the >10,000 <100,000 molecular weight fraction; in waters treated to destroy dissolved organic carbon, it was generally in the >100,000 molecular weight fraction.Copper concentrations in intact bedload sediments from the intake area of Surry ranged from 2.3 to 26 and of Salem from 36 to 74 ..mu..g/g dry weight; those in the discharge area of Surry ranged from 13 to 30 and of Salem from 3 to 67. We noted considerable spatial heterogeneity both at the intake and discharge areas, and higher copper concentrations in the <62-..mu..m fraction than in intact sediments.« less

Synthesis and characterization of alginate beads encapsulated zinc oxide nanoparticles for bacteria disinfection in water.

PubMed

Motshekga, Sarah Constance; Sinha Ray, Suprakas; Maity, Arjun

2018-02-15

The use of polymer nanocomposites as novel materials for water remediation has emerged as a promising alternative for disinfection of bacteria contaminated water. Sodium alginate, a natural biopolymer has been investigated in this study by encapsulating antimicrobial zinc oxide nanoparticles supported bentonite. The confirmation of the alginate nanocomposites was done by use of TEM, SEM-EDS and XRD. The antimicrobial activity of the alginate nanocomposites was investigated by batch studies using surface water and synthetic bacteria contaminated water containing Staphylococcus aureus. The effect of nanocomposite amount and initial bacteria concentration has been studied. The inactivation results indicated that the nanocomposite effectively inactivated bacteria in both the synthetic and surface water. With an amount of 0.5 g of the nanocomposites, no bacteria was observed in the water after 70 min of contact time with initial bacteria concentration of 200 cfu/ml for synthetic water and within a min, no bacteria was observed in the water for surface water. It is worth noting that 200 cfu/ml is the bacteria concentration range in which environmental water is likely to contain. Therefore, the results of this study have indicated that the alginate nanocomposites can be deemed as a potential antimicrobial agent for water disinfection. Copyright © 2017 Elsevier Inc. All rights reserved.

Adsorption of Cd2+ ions on plant mediated SnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Haq, Sirajul; Rehman, Wajid; Waseem, Muhammad; Shahid, Muhammad; Mahfooz-ur-Rehman; Hussain Shah, Khizar; Nawaz, Mohsan

2016-10-01

Plant mediated SnO2 nanoparticles were synthesized by using SnCl4.5H2O as a precursor material. The nanoparticles were then characterized for BET surface area measurements, energy dispersive x-rays (EDX), scanning electron microscopy (SEM), UV-vis diffuse reflectance (DRS) spectra and x-rays diffraction (XRD) analysis. The successful synthesis of SnO2 nanoparticles was confirmed by EDX analysis. The particle sizes were in the range 19-27 nm whereas the crystallite size computed from XRD measurement was found to be 19.9 nm. Batch adsorption technique was employed for the removal of Cd2+ ions from aqueous solution. The sorption studies of Cd2+ ions were performed at pHs 4 and 6. The equilibrium concentration of Cd2+ ions was determined by atomic absorption spectrometer (flame mode). The uptake of Cd2+ ions was affected by initial concentration, pH and temperature of the electrolytic solution. It was observed that the adsorption of Cd2+ ions enhanced with increase in the initial concentration of Cd2+ ions whereas a decrease in the percent adsorption was detected. From the thermodynamic parameters, the adsorption process was found spontaneous and endothermic in nature. The n values confirmed 2:1 exchange mechanism between surface protons and Cd2+ ions.

Use of a small molecule as an initiator for interchain staudinger reaction: A new ATP sensing platform using product fluorescence.

PubMed

Yu, Huan; Zheng, Jing; Yang, Sheng; Asiri, Abdullah M; Alamry, Khalid A; Sun, Mingtai; Zhang, Kui; Wang, Suhua; Yang, Ronghua

2018-02-01

We demonstrated that a small molecule induced interchain Staudinger reaction can be employed for highly selective detection of adenosine triphosphate (ATP), an important energy-storage biomolecule. A designed ATP split aptamer (A1) was first functionalized with a weakly fluorescent coumarin derivative due to an azide group (azido-coumarin). The second DNA strand (A2) was covalently linked with triphenylphosphine, which could selectively and efficiently reduce azido to amino group through the Staudinger reaction. The A2 was then hybridized with a half of another designed longer DNA strand (T1). The second half of T1 was a split aptamer and selectively recognized ATP with A1 to form a sandwich structure. The specific interaction between ATP and the aptamers drew the two functionalized DNA strands (A1 and A2) together to initiate the interchain Staudinger reduction at fmol-nmol concentration level, hence produced fluorescent 7-aminocoumarin which could be used as an indicator for the presence of trace ATP. The reaction process had a concentration dependent manner with ATP in a large concentration range. Such a strategy of interchain Staudinger reaction can be extended to construct biosensors for other small functional molecules on the basis of judiciously designed aptamers. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of microalgal treatments on pesticides in water.

PubMed

Hultberg, Malin; Bodin, Hristina; Ardal, Embla; Asp, Håkan

2016-01-01

The effect of the microalgae Chlorella vulgaris on a wide range of different pesticides in water was studied. Treatments included short-term exposure (1 h) to living and dead microalgal biomass and long-term exposure (4 days) to actively growing microalgae. The initial pesticide concentration was 63.5 ± 3.9 µg L(-1). There was no significant overall reduction of pesticides after short-term exposure. A significant reduction of the total amount of pesticides was achieved after the long-term exposure to growing microalgae (final concentration 29.7 ± 1.0 µg L(-1)) compared with the long-term control (37.0 ± 1.2 µg L(-1)). The concentrations of 10 pesticides out of 38 tested were significantly lowered in the long-term algal treatment. A high impact of abiotic factors such as sunlight and aeration for pesticide reduction was observed when the initial control (63.5 ± 3.9 µg L(-1)) and the long-term control (37.0 ± 1.2 µg L(-1)) were compared. The results suggest that water treatment using microalgae, natural inhabitants of polluted surface waters, could be further explored not only for removal of inorganic nutrients but also for removal of organic pollutants in water.

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

Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.

The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analysing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analysed period corresponds to the wet seasonmore » (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D≤50 µm in order to capture the processes leading up to the precipitation formation. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40% for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km ₋1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (>20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision–coalescence process. The overall shape of the droplet size distribution (DSD) does not appear to be predominantly determined by updraught strength, especially beyond the 20 µm range. The aerosol conditions play a major role in that case. However, the updraughts modulate the DSD concentrations and are responsible for the vertical transport of water in the cloud. The larger droplets found in background clouds are associated with weak water vapour competition and a bimodal distribution of droplet sizes in the lower levels of the cloud, which enables an earlier initiation of the collision–coalescence process. This study shows that the pollution produced by Manaus significantly affects warm-phase microphysical properties of the surrounding clouds by changing the initial DSD formation. The corresponding effects on ice-phase processes and precipitation formation will be the focus of future endeavours.« less

Accelerated removal of high concentration p-chloronitrobenzene using bioelectrocatalysis process and its microbial communities analysis.

PubMed

Peng, Xinhong; Pan, Xianhui; Wang, Xin; Li, Dongyang; Huang, Pengfei; Qiu, Guanhua; Shan, Ke; Chu, Xizhang

2018-02-01

p-Chloronitrobenzene (p-CNB) is a persistent refractory and toxic pollutant with a concentration up to 200 mg/L in industrial wastewater. Here, a super-fast removal rate was found at 0.2-0.8 V of external voltage over a p-CNB concentration of 40-120 mg/L when a bioelectrochemical technology is used comparing to the natural biodegradation and electrochemical methods. The reduction kinetics (k) was fitted well according to pseudo-first order model with respect to the different initial concentration, indicating a 1.12-fold decrease from 1.80 to 0.85 h -1 within the experimental range. Meanwhile, the highest k was provided at 0.5 V with the characteristic of energy saving. It was revealed that the functional bacterial (Propionimicrobium, Desulfovibrio, Halanaerobium, Desulfobacterales) was selectively enriched under electro-stimulation, which possibly processed Cl-substituted nitro-aromatics reduction. The possible degradation pathway was also proposed. This work provides the beneficial choice on the rapid treatment of high-concentration p-CNB wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Contaminant degradation by irradiated semiconducting silver chloride particles: kinetics and modelling.

PubMed

Ma, Tian; Garg, Shikha; Miller, Christopher J; Waite, T David

2015-05-15

The kinetics and mechanism of light-mediated formic acid (HCOO(-)) degradation in the presence of semiconducting silver chloride particles are investigated in this study. Our experimental results show that visible-light irradiation of AgCl(s) results in generation of holes and electrons with the photo-generated holes and its initial oxidation product carbonate radical, oxidizing HCOO(-) to form CO2. The HCOO(-) degradation rate increases with increase in silver concentration due to increase in rate of photo-generation of holes while the increase in chloride concentration decreases the degradation rate of HCOO(-) as a result of the scavenging of holes by Cl(-), thereby resulting in decreased holes and carbonate radical concentration. The results obtained indicate that a variety of other solution conditions including dioxygen concentration, bicarbonate concentration and pH influence the availability of holes and hence the HCOO(-) degradation rate in a manner consistent with our understanding of key processes. Based on our experimental results, we have developed a kinetic model capable of predicting AgCl(s)-mediated HCOO(-) photo-degradation over a wide range of conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

NASA Technical Reports Server (NTRS)

Davis, Craig R.; Waldman, Frank A.

1993-01-01

The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries.

Removal of cadmium from aqueous solutions using industrial coal fly ash-nZVI.

PubMed

Ma, Lixia; Wei, Qi; Chen, Yueqin; Song, Qiuyang; Sun, Conghui; Wang, Zhiqiang; Wu, Guanghong

2018-02-01

Batch experiments were conducted to test the effects of various solution properties, such as pH, temperature, initial concentration and anoxic and aerobic atmosphere, on Cd removal by nanoscale zerovalent iron (nZVI) supported on industrial coal fly ash. Cd (II) could be removed by adsorption on fly ash-nZVI in a very short time (5 min) with high removal rates (greater than 99.9%) over a wide range of concentration (5-100 mg l -1 ). Cd (II) was physically adsorbed on the surface of fly ash-nZVI. The preparation of fly ash-nZVI can incorporate the use of waste media, making the overall adsorbent more removal efficient and low cost.

Removal of cadmium from aqueous solutions using industrial coal fly ash-nZVI

PubMed Central

Ma, Lixia; Wei, Qi; Chen, Yueqin; Song, Qiuyang; Sun, Conghui; Wang, Zhiqiang

2018-01-01

Batch experiments were conducted to test the effects of various solution properties, such as pH, temperature, initial concentration and anoxic and aerobic atmosphere, on Cd removal by nanoscale zerovalent iron (nZVI) supported on industrial coal fly ash. Cd (II) could be removed by adsorption on fly ash-nZVI in a very short time (5 min) with high removal rates (greater than 99.9%) over a wide range of concentration (5–100 mg l−1). Cd (II) was physically adsorbed on the surface of fly ash-nZVI. The preparation of fly ash-nZVI can incorporate the use of waste media, making the overall adsorbent more removal efficient and low cost. PMID:29515830

Effects of acetic acid, ethanol, and SO(2) on the removal of volatile acidity from acidic wines by two Saccharomyces cerevisiae commercial strains.

PubMed

Vilela-Moura, Alice; Schuller, Dorit; Mendes-Faia, Arlete; Côrte-Real, Manuela

2010-07-01

Herein, we report the influence of different combinations of initial concentration of acetic acid and ethanol on the removal of acetic acid from acidic wines by two commercial Saccharomyces cerevisiae strains S26 and S29. Both strains reduced the volatile acidity of an acidic wine (1.0 gl(-1) acetic acid and 11% (v/v) ethanol) by 78% and 48%, respectively. Acetic acid removal by strains S26 and S29 was associated with a decrease in ethanol concentration of 0.7 and 1.2% (v/v), respectively. Strain S26 revealed better removal efficiency due to its higher tolerance to stress factors imposed by acidic wines. Sulfur dioxide (SO(2)) in the concentration range 95-170 mg l(-1)inhibits the ability of both strains to reduce the volatile acidity of the acidic wine used under our experimental conditions. Therefore, deacidification should be carried out either in wines stabilized by filtration or in wines with SO(2)concentrations up to 70 mg l(-1). Deacidification of wines with the better performing strain S26 was associated with changes in the concentration of volatile compounds. The most pronounced increase was observed for isoamyl acetate (banana) and ethyl hexanoate (apple, pineapple), with an 18- and 25-fold increment, respectively, to values above the detection threshold. The acetaldehyde concentration of the deacidified wine was 2.3 times higher, and may have a detrimental effect on the wine aroma. Moreover, deacidification led to increased fatty acids concentration, but still within the range of values described for spontaneous fermentations, and with apparently no negative impact on the organoleptical properties.

Evaluating the Relationship between Vancomycin Trough Concentration and 24-Hour Area under the Concentration-Time Curve in Neonates.

PubMed

Tseng, Sheng-Hsuan; Lim, Chuan Poh; Chen, Qi; Tang, Cheng Cai; Kong, Sing Teang; Ho, Paul Chi-Lui

2018-04-01

Bacterial sepsis is a major cause of morbidity and mortality in neonates, especially those involving methicillin-resistant Staphylococcus aureus (MRSA). Guidelines by the Infectious Diseases Society of America recommend the vancomycin 24-h area under the concentration-time curve to MIC ratio (AUC 24 /MIC) of >400 as the best predictor of successful treatment against MRSA infections when the MIC is ≤1 mg/liter. The relationship between steady-state vancomycin trough concentrations and AUC 24 values (mg·h/liter) has not been studied in an Asian neonatal population. We conducted a retrospective chart review in Singapore hospitals and collected patient characteristics and therapeutic drug monitoring data from neonates on vancomycin therapy over a 5-year period. A one-compartment population pharmacokinetic model was built from the collected data, internally validated, and then used to assess the relationship between steady-state trough concentrations and AUC 24 A Monte Carlo simulation sensitivity analysis was also conducted. A total of 76 neonates with 429 vancomycin concentrations were included for analysis. Median (interquartile range) was 30 weeks (28 to 36 weeks) for postmenstrual age (PMA) and 1,043 g (811 to 1,919 g) for weight at the initiation of treatment. Vancomycin clearance was predicted by weight, PMA, and serum creatinine. For MRSA isolates with a vancomycin MIC of ≤1, our major finding was that the minimum steady-state trough concentration range predictive of achieving an AUC 24 /MIC of >400 was 8 to 8.9 mg/liter. Steady-state troughs within 15 to 20 mg/liter are unlikely to be necessary to achieve an AUC 24 /MIC of >400, whereas troughs within 10 to 14.9 mg/liter may be more appropriate. Copyright © 2018 American Society for Microbiology.

Comparison between electrocoagulation and chemical precipitation for metals removal from acidic soil leachate.

PubMed

Meunier, Nathalie; Drogui, Patrick; Montané, Camille; Hausler, Robert; Mercier, Guy; Blais, Jean-François

2006-09-01

This paper provides a quantitative comparison between electrocoagulation and chemical precipitation based on heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) removal from acidic soil leachate (ASL) at the laboratory pilot scale. Chemical precipitation was evaluated using either calcium hydroxide or sodium hydroxide, whereas electrocoagulation was evaluated via an electrolytic cell using mild steel electrodes. Chemical precipitation was as effective as electrocoagulation in removing metals from ASL having low contamination levels (30 mg Pbl(-1) and 18 mg Znl(-1)). For ASL enriched with different metals (each concentration of metals was initially adjusted to 100 mg l(-1)), the residual Cr, Cu, Pb and Zn concentrations at the end of the experiments were below the acceptable level recommended for discharge in sewage urban works (more than 99.8% of metal was removed) using either electrocoagulation or chemical precipitation. Cd was more effectively removed by electrochemical treatment, whereas Ni was easily removed by chemical treatment. The cost for energy, chemicals and disposal of metallic residue of electrocoagulation process ranged from USD 8.83 to 13.95 tds(-1), which was up to five times lower than that recorded using chemical precipitation. Highly effective electrocoagulation was observed as the ASL was specifically enriched with high concentration of Pb (250-2000 mg Pbl(-1)). More than 99.5% of Pb was removed regardless of the initial Pb concentration imposed in ASL and, in all cases, the residual Pb concentrations (0.0-1.44 mg l(-1)) were below the limiting value (2.0 mg l(-1)) for effluent discharge in sewage works.

Treatment of petroleum drill cuttings using bioaugmentation and biostimulation supplemented with phytoremediation.

PubMed

Kogbara, Reginald B; Ogar, Innocent; Okparanma, Reuben N; Ayotamuno, Josiah M

2016-07-28

This study sought to compare the effectiveness of bioaugmentation and biostimulation, as well as the combination of both techniques, supplemented with phytoremediation, in the decontamination of petroleum drill cuttings. Drill cuttings with relatively low concentration of total petroleum hydrocarbons (TPH) and metals were mixed with soil in the ratio 5:1 and treated with three different combinations of the bioremediation options. Option A entailed bioaugmentation supplemented with phytoremediation. Option B had the combination of biostimulation and bioaugmentation supplemented with phytoremediation. While biostimulation supplemented with phytoremediation was deployed in option C. Option O containing the drill cuttings-soil mixture without treatment served as untreated control. Fertilizer application, tillage and watering were used for biostimulation treatment, while spent mushroom substrate (Pleurotus ostreatus) and elephant grass (Pennisetum purpureum) were employed for bioaugmentation and phytoremediation treatment, respectively. The drill cuttings-soil mixtures were monitored for TPH, organic carbon, total nitrogen, pH, metal concentrations, and fungal counts, over time. After 56 days of treatment, there was a decline in the initial TPH concentration of 4,114 mg kg(-1) by 5.5%, 68.3%, 75.6% and 48% in options O, A, B and C, respectively. Generally, higher TPH loss resulted from the phytoremediation treatment stage. The treated options also showed slight reductions in metal concentrations ranging from 0% to 16% of the initial low concentrations. The results highlight the effectiveness of bioaugmentation supplemented with phytoremediation. The combination of bioaugmentation and biostimulation supplemented with phytoremediation, however, may prove better in decontaminating petroleum drill cuttings to environmentally benign levels.

Cinetica de oxidacion de polimeros conductores: poli-3,4- etilendioxitiofeno

NASA Astrophysics Data System (ADS)

Caballero Romero, Maria

Films of poly-3,4-ethylenedioxythiophene (PEDOT) perchlorate used as electrodes in liquid electrolytes incorporate anions and solvent during oxidation for charge and osmotic balance: the film swells. During reduction the film shrinks, closes its structure trapping counterions getting then rising conformational packed states by expulsion of counterions and solvent. Here by potential step from the same reduced initial state to the same oxidized final state the rate coefficient, the activation energy and reaction orders related to the counterion concentration in solution and to the concentration of active centers in the polymer film, were attained following the usual methodology used for chemical and electrochemical kinetics. Now the full methodology was repeated using different reduced-shrunk or reduced-conformational compacted initial states every time. Those initial states were attained by reduction of the oxidized film at rising cathodic potentials for the same reduction time each. Rising reduced and conformational compacted states give slower subsequent oxidation rates by potential step to the same anodic potential every time. The activation energy, the reaction coefficient and reaction orders change for rising conformational compacted initial states. Decreasing rate constants and increasing activation energies are obtained for the PEDOT oxidation from increasing conformational compacted initial states. The experimental activation energy presents two linear ranges as a function of the initial reduced-compacted state. Using as initial states for the oxidation open structures attained by reduction at low cathodic potentials, activation energies attained were constant: namely the chemical activation energy. Using as initial states for the oxidation deeper reduced, closed and packed conformational structures, the activation energy includes two components: the constant chemical energy plus the conformational energy required to relax the conformational structure generating free volume which allows the entrance of the balancing counterions required for the reaction. The conformational energy increases linearly as a function of the reduction-compaction potential. The kinetic magnitudes include conformational and structural information. The Chemical Kinetics becomes Structural (or conformational) Chemical Kinetics.

Influence of Algae Age and Population on the Response to TiO₂ Nanoparticles.

PubMed

Metzler, David M; Erdem, Ayca; Huang, Chin Pao

2018-03-25

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO₂ NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3-4.2 × 10⁶ cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO₂ NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae.

Influence of Algae Age and Population on the Response to TiO2 Nanoparticles

PubMed Central

Metzler, David M.; Erdem, Ayca; Huang, Chin Pao

2018-01-01

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO2 NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3−4.2 × 106 cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO2 NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae. PMID:29587381

Field and Laboratory Responses of Male Leaf Roller Moths, Choristoneura rosaceana and Pandemis pyrusana, to Pheromone Concentrations in an Attracticide Paste Formulation

PubMed Central

Curkovic, Tomislav; Brunner, Jay F.; Landolt, Peter J.

2009-01-01

Male leafroller moths, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) and Pandemis pyrusana (Kearfott), were evaluated for responses to a paste formulation loaded with a range of concentrations of the two species' pheromone blends and evaluated in a laboratory wind tunnel and in the field. Response criteria were flight, flight towards the pheromone source, and contact with the pheromone source for the wind tunnel assays, and capture of moths in traps for the field tests. In the wind tunnel and field, responses of males of both species to the paste generally increased as the pheromone concentration in the paste was increased. There was little response by either species to paste with less than 0.16% pheromone. The relationship between pheromone concentration and response for P. pyrusana was linear and for C. rosaceana was sinusoidal over the range of pheromone concentrations tested. These patterns were seen both in the wind tunnel and in the field. Initial release rates from the paste of (Z)-11-tetradecenyl acetate, the main component of the pheromone blends of both species was 3.6–3.8 ng/h. Inhibitory thresholds for responses were not reached for either species, using pheromone concentrations as high as 16%, in either the wind tunnel or the field. For both species, response of males to rubber septa with one mg pheromone loads was similar to the response to the paste with pheromone at concentrations greater than 3–4%. For C. rosaceana, rates of contact with the paste in the wind tunnel were statistically similar to rates of contact in response to conspecific females, with paste pheromone concentrations above 1.6%. Response rates for males of P. pyrusana were significantly lower to the paste than to conspecific females at all paste pheromone concentrations tested. Overall, the optimum pheromone concentration in the paste for moth attraction to contact was 3.2 % for C. rosaceana and 8% for P. pyrusana. PMID:19619030

Ethanol inhibition kinetics of Kluyveromyces marxianus grown on Jerusalem artichoke juice

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

Bajpai, P.; Margaritis, A.

1982-12-01

The kinetics of ethanol inhibition on cell growth and ethanol production by Kluyveromyces marxianus UCD (FST) 55-82 were studied during batch growth. The liquid medium contained 10% (weight/volume) inulin-type sugars derived from an extract of Jerusalem artichoke (Helianthus tuberosus) tubers, supplemented with small amounts of Tween 80, oleic acid, and corn steep liquor. Initial ethanol concentrations ranging from 0 to 80 g/liter in the liquid medium were used to study the inhibitory effect of ethanol on the following parameters: maximum specific growth rate (mu max), cell and ethanol yields, and sugar utilization. It was found that as the initial ethanolmore » concentration increased from 0 to 80 g/liter, and maximum specific growth rate of K. marxianus cells decreased from 0.42 to 0.09/hour, whereas the ethanol and cell yields and sugar utilization remained almost constant. A simple kinetic model was used to correlate the mu max results and the rates of cell and ethanol production, and the appropriate constants were evaluated. (Refs. 22).« less

Catalase purification from rat liver with iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) cryogel discs.

PubMed

Göktürk, Ilgım; Perçin, Işık; Denizli, Adil

2016-08-17

In this study, iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) (PHEMAGA/Fe(3+)) cryogel discs were prepared. The PHEMAGA/Fe(3+) cryogel discs were characterized by elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, swelling tests, and surface area measurements. The PHEMAGA/Fe(3+) cryogel discs had large pores ranging from 10 to 100 µm with a swelling degree of 9.36 g H2O/g cryogel. Effects of pH, temperature, initial catalase concentration, and flow rate on adsorption capacity of the PHEMAGA/Fe(3+) cryogel discs were investigated. Maximum catalase adsorption capacity (62.6 mg/g) was obtained at pH 7.0, 25°C, and 3 mg/ml initial catalase concentration. The PHEMAGA/Fe(3+) cryogel discs were also tested for the purification of catalase from rat liver. After tissue homogenization, purification of catalase was performed using the PHEMAGA/Fe(3+) cryogel discs and catalase was obtained with a yield of 54.34 and 16.67 purification fold.

Toxic hexavalent chromium reduction by Bacillus pumilis, Cellulosimicrobium cellulans and Exiguobacterium

NASA Astrophysics Data System (ADS)

Rehman, Fatima; Faisal, Muhammad

2015-05-01

Three bacterial strains Bacillus pumilis, Cellulosimicrobium cellulans and Exiguobacterium were investigated when grown in Luria-Bertani (LB) medium at 500 μg/mL Cr(VI). The hexavalent chromium reduction was measured by growing the strains in DeLeo and Ehrlich (1994) medium at 200 and 400 μg/mL K2CrO4. The optimal Cr (VI) reduction by strains B. pumilis, Exigubacterium and C. cellulans was 51%, 39%, and 41%, respectively, at an initial K2CrO4 concentration of 200 μg/mL at pH 3 and temperature 37°C. At an initial chromate concentration of 400 μg/mL, the Cr(VI) reduction by strains B. pumilis, Exigubacterium and C. cellulans was 24%, 19%, and 18%, respectively at pH 3 at 37°C after 24 h. These strains have ability to reduce toxic hexavalent chromium to the less mobile trivalent chromium at a wide range of different environmental conditions and can be useful for the treatment of contaminated wastewater and soils.

Real-time measurement of size-resolved elemental composition ratio for flame synthesized composite nanoparticle aggregates using a tandem SMPS-ICP-OES

PubMed Central

Reed, Nathan; Fang, Jiaxi; Chavalmane, Sanmathi; Biswas, Pratim

2017-01-01

Composite nanoparticles find application in catalysis, drug delivery, and energy storage and require increasingly fine control of their physical properties and composition. While composite nanoparticles have been widely synthesized and characterized, little work has systematically correlated the initial concentration of precursors and the final composition of flame synthesized composite nanoparticles. This relationship is explored in a diffusion flame aerosol reactor by coupling a scanning mobility particle sizer (SMPS) with an inductively coupled plasma optical emission spectrometer (ICP-OES). A framework for studying the relationship between the initial precursor concentrations of different elements and the final nanoparticle composition is explored. The size-resolved elemental composition was measured by directly injecting size-selected fractions of aggregated magnetite and silicon dioxide composite nanoparticles into the ICP-OES plasma. This work showed a correlation between precursor molar ratio and the measured elemental ratio in the mobility size range of 50 to 140 nm. Building on previous work studying size resolved elemental composition of engineered nanoparticles, the analysis is extended to flame synthesized composite nanoparticle aggregates in this work. PMID:28435179

Real-time measurement of size-resolved elemental composition ratio for flame synthesized composite nanoparticle aggregates using a tandem SMPS-ICP-OES.

PubMed

Reed, Nathan; Fang, Jiaxi; Chavalmane, Sanmathi; Biswas, Pratim

2017-01-01

Composite nanoparticles find application in catalysis, drug delivery, and energy storage and require increasingly fine control of their physical properties and composition. While composite nanoparticles have been widely synthesized and characterized, little work has systematically correlated the initial concentration of precursors and the final composition of flame synthesized composite nanoparticles. This relationship is explored in a diffusion flame aerosol reactor by coupling a scanning mobility particle sizer (SMPS) with an inductively coupled plasma optical emission spectrometer (ICP-OES). A framework for studying the relationship between the initial precursor concentrations of different elements and the final nanoparticle composition is explored. The size-resolved elemental composition was measured by directly injecting size-selected fractions of aggregated magnetite and silicon dioxide composite nanoparticles into the ICP-OES plasma. This work showed a correlation between precursor molar ratio and the measured elemental ratio in the mobility size range of 50 to 140 nm. Building on previous work studying size resolved elemental composition of engineered nanoparticles, the analysis is extended to flame synthesized composite nanoparticle aggregates in this work.

Purging of a tank-mounted multilayer insulation system by gas diffusion

NASA Technical Reports Server (NTRS)

Sumner, I. E.

1978-01-01

The investigation was conducted on a multilayer insulation (MLI) system mounted on a spherical liquid hydrogen propellant tank. The MLI consisted of two blankets of insulation each containing 15 double-aluminized Mylar radiation shields separated by double silk net spacers. The gaseous nitrogen initially contained within the MLI system and vacuum chamber was purged with gaseous helium introduced both underneath the MLI and into the vacuum chamber. The MLI panels were assumed to be purged primarily by means of gas diffusion. Overall, test results indicated that nitrogen concentrations well below 1 percent could be achieved everywhere within the MLI system. Typical times to achieve 1 percent nitrogen concentration within the MLI panels ranged from 69 minutes at the top of the tank to 158 minutes at the bottom of the tank. Four space-hold thermal performance tests indicated no significant thermal degradation of the MLI system had occurred due to the purge tests conducted. The final measured heat input attributed to the MLI was 7.23 watts as compared to 7.18 watts for the initial baseline thermal performance test.

Can electrocoagulation process be an appropriate technology for phosphorus removal from municipal wastewater?

PubMed

Nguyen, D Duc; Ngo, H Hao; Guo, W; Nguyen, T Thanh; Chang, Soon W; Jang, A; Yoon, Yong S

2016-09-01

This paper evaluated a novel pilot scale electrocoagulation (EC) system for improving total phosphorus (TP) removal from municipal wastewater. This EC system was operated in continuous and batch operating mode under differing conditions (e.g. flow rate, initial concentration, electrolysis time, conductivity, voltage) to evaluate correlative phosphorus and electrical energy consumption. The results demonstrated that the EC system could effectively remove phosphorus to meet current stringent discharge standards of less than 0.2mg/L within 2 to 5min. This target was achieved in all ranges of initial TP concentrations studied. It was also found that an increase in conductivity of solution, voltages, or electrolysis time, correlated with improved TP removal efficiency and reduced specific energy consumption. Based on these results, some key economic considerations, such as operating costs, cost-effectiveness, product manufacturing feasibility, facility design and retrofitting, and program implementation are also discussed. This EC process can conclusively be highly efficient in a relatively simple, easily managed, and cost-effective for wastewater treatment system. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Cashew Apple Juice for the Production of Fuel Ethanol

NASA Astrophysics Data System (ADS)

Pinheiro, Álvaro Daniel Teles; Rocha, Maria Valderez Ponte; Macedo, Gorete R.; Gonçalves, Luciana R. B.

A commercial strain of Saccharomyces cerevisiae was used for the production of ethanol by fermentation of cashew apple juice. Growth kinetics and ethanol productivity were calculated for batch fermentation with different initial sugar (glucose + fructose) concentrations. Maximal ethanol, cell, and glycerol concentrations were obtained when 103.1 g L-1 of initial sugar concentration was used. Cell yield (Yx/s) was calculated as 0.24 (g microorganism)/(g glucose + fructose) using cashew apple juice medium with 41.3 g L-1 of initial sugar concentration. Glucose was exhausted first, followed by fructose. Furthermore, the initial concentration of sugars did not influence ethanol selectivity. These results indicate that cashew apple juice is a suitable substrate for yeast growth and ethanol production.

Evaluation of cashew apple juice for the production of fuel ethanol.

PubMed

Pinheiro, Alvaro Daniel Teles; Rocha, Maria Valderez Ponte; Macedo, Gorete R; Gonçalves, Luciana R B

2008-03-01

A commercial strain of Saccharomyces cerevisiae was used for the production of ethanol by fermentation of cashew apple juice. Growth kinetics and ethanol productivity were calculated for batch fermentation with different initial sugar (glucose + fructose) concentrations. Maximal ethanol, cell, and glycerol concentrations were obtained when 103.1 g L(-1) of initial sugar concentration was used. Cell yield (Y (X/S)) was calculated as 0.24 (g microorganism)/(g glucose + fructose) using cashew apple juice medium with 41.3 g L(-1) of initial sugar concentration. Glucose was exhausted first, followed by fructose. Furthermore, the initial concentration of sugars did not influence ethanol selectivity. These results indicate that cashew apple juice is a suitable substrate for yeast growth and ethanol production.

Quantitative and predictive model of kinetic regulation by E. coli TPP riboswitches

PubMed Central

Guedich, Sondés; Puffer-Enders, Barbara; Baltzinger, Mireille; Hoffmann, Guillaume; Da Veiga, Cyrielle; Jossinet, Fabrice; Thore, Stéphane; Bec, Guillaume; Ennifar, Eric; Burnouf, Dominique; Dumas, Philippe

2016-01-01

ABSTRACT Riboswitches are non-coding elements upstream or downstream of mRNAs that, upon binding of a specific ligand, regulate transcription and/or translation initiation in bacteria, or alternative splicing in plants and fungi. We have studied thiamine pyrophosphate (TPP) riboswitches regulating translation of thiM operon and transcription and translation of thiC operon in E. coli, and that of THIC in the plant A. thaliana. For all, we ascertained an induced-fit mechanism involving initial binding of the TPP followed by a conformational change leading to a higher-affinity complex. The experimental values obtained for all kinetic and thermodynamic parameters of TPP binding imply that the regulation by A. thaliana riboswitch is governed by mass-action law, whereas it is of kinetic nature for the two bacterial riboswitches. Kinetic regulation requires that the RNA polymerase pauses after synthesis of each riboswitch aptamer to leave time for TPP binding, but only when its concentration is sufficient. A quantitative model of regulation highlighted how the pausing time has to be linked to the kinetic rates of initial TPP binding to obtain an ON/OFF switch in the correct concentration range of TPP. We verified the existence of these pauses and the model prediction on their duration. Our analysis also led to quantitative estimates of the respective efficiency of kinetic and thermodynamic regulations, which shows that kinetically regulated riboswitches react more sharply to concentration variation of their ligand than thermodynamically regulated riboswitches. This rationalizes the interest of kinetic regulation and confirms empirical observations that were obtained by numerical simulations. PMID:26932506

Quantitative and predictive model of kinetic regulation by E. coli TPP riboswitches.

PubMed

Guedich, Sondés; Puffer-Enders, Barbara; Baltzinger, Mireille; Hoffmann, Guillaume; Da Veiga, Cyrielle; Jossinet, Fabrice; Thore, Stéphane; Bec, Guillaume; Ennifar, Eric; Burnouf, Dominique; Dumas, Philippe

2016-01-01

Riboswitches are non-coding elements upstream or downstream of mRNAs that, upon binding of a specific ligand, regulate transcription and/or translation initiation in bacteria, or alternative splicing in plants and fungi. We have studied thiamine pyrophosphate (TPP) riboswitches regulating translation of thiM operon and transcription and translation of thiC operon in E. coli, and that of THIC in the plant A. thaliana. For all, we ascertained an induced-fit mechanism involving initial binding of the TPP followed by a conformational change leading to a higher-affinity complex. The experimental values obtained for all kinetic and thermodynamic parameters of TPP binding imply that the regulation by A. thaliana riboswitch is governed by mass-action law, whereas it is of kinetic nature for the two bacterial riboswitches. Kinetic regulation requires that the RNA polymerase pauses after synthesis of each riboswitch aptamer to leave time for TPP binding, but only when its concentration is sufficient. A quantitative model of regulation highlighted how the pausing time has to be linked to the kinetic rates of initial TPP binding to obtain an ON/OFF switch in the correct concentration range of TPP. We verified the existence of these pauses and the model prediction on their duration. Our analysis also led to quantitative estimates of the respective efficiency of kinetic and thermodynamic regulations, which shows that kinetically regulated riboswitches react more sharply to concentration variation of their ligand than thermodynamically regulated riboswitches. This rationalizes the interest of kinetic regulation and confirms empirical observations that were obtained by numerical simulations.

Cellular glutathione level does not predict ovarian cancer cells' resistance after initial or repeated exposure to cisplatin.

PubMed

Nikounezhad, Nastaran; Nakhjavani, Maryam; Shirazi, Farshad H

2017-05-01

Cisplatin resistance development is a major obstacle in ovarian cancer treatment. One of the most important mechanisms underlying cisplatin resistance is drug detoxification by glutathione. In the present study, the importance of initial or repeated exposure to cisplatin in glutathione dependent resistance was investigated. To this purpose, some cisplatin sensitive and resistant variants of human ovarian cancer cell lines providing an appropriate range of cisplatin sensitivity were selected. Clonogenic survival assay was performed to evaluate cisplatin resistance and intracellular contents of reduced (GSH) and oxidized (GSSG) glutathione were analyzed using an HPLC method. Our results indicated that the intracellular GSH and GSSG concentrations were nearly equal in A2780 and A2780CP cells, while the A2780CP cells showed 14 times more resistance than the A2780 cells after initial exposure to cisplatin. A2780-R1 and A2780-R3 cells which have been repeatedly exposed to cisplatin also showed no significant difference in glutathione content, even though A2780-R3 was about two times more resistant than A2780-R1. Moreover, intracellular GSH/GSSG ratio decreased in the resistant cells, reflecting a shift towards a more oxidizing intracellular environment indicative of oxidative stress. As a conclusion, it seems that although the intracellular glutathione concentration increases after repeated exposure to cisplatin, there is no clear correlation between the intracellular GSH content in ovarian cancer cells and their resistance to cisplatin neither after initial nor after repeated exposure to this drug.

Equilibrium and kinetic modelling of cadmium (II) biosorption by Dried Biomass Aphanothece sp. from aqueous phase

NASA Astrophysics Data System (ADS)

Awalina; Harimawan, A.; Haryani, G. S.; Setiadi, T.

2017-05-01

The Biosorption of cadmium (II) ions on dried biomass of Aphanothece sp.which previously grown in a photobioreactor system with atmospheric carbon dioxide fed input, was studied in a batch system with respect to initial pH, biomass concentration, contact time, and temperature. The biomass exhibited the highest cadmium (II) uptake capacity at 30ºC, initial pH of 8.0±0.2 in 60 minute and initial cadmium (II) ion concentration of 7.76 mg/L. Maximum biosorption capacities were 16.47 mg/g, 54.95 mg/g and 119.05 mg/g at range of initial cadmium (II) 0.96-3.63 mg/L, 1.99-8.10 mg/L and 6.48-54.38 mg/L, respectively. Uptake kinetics follows the pseudo-second order model while equilibrium is best described by Langmuir isotherm model. Isotherms have been used to determine thermodynamic parameter process (free energy change, enthalpy change and entropy change). FTIR analysis of microalgae biomass revealed the presence of amino acids, carboxyl, hydroxyl, sulfhydryl and carbonyl groups, which are responsible for biosorption of metal ions. During repeated sorption/desorption cycles, the ratio of Cd (II) desorption to biosorption decreased from 81% (at first cycle) to only 27% (at the third cycle). Nevertheless, due to its higher biosorption capability than other adsorbent, Aphanothece sp appears to be a good biosorbent for removing metal Cd (II) ions from aqueous phase.

Direct Measurement of Initial 230TH/ 232TH Ratios in Central Texas Speleothems for More Accurate Age Determination

NASA Astrophysics Data System (ADS)

Wortham, B. E.; Banner, J. L.; James, E.; Loewy, S. L.

2013-12-01

Speleothems, calcite deposits in caves, preserve a record of climate in their growth rate, isotope ratios and trace element concentrations. These variables must be tied to precise ages to produce pre-instrumental records of climate. The 238U-234U- 230Th disequilibrium method of dating can yield precise ages if the amount of 230Th from the decay of radiogenic 238U can be constrained. 230Th in a speleothem calcite growth layer has two potential sources - 1) decay of radioactive 238U since the time of growth of the calcite layer; and 2) initial detrital 230Th, incorporated along with detrital 232Th, into the calcite layer at the time it grew. Although the calcite lattice does not typically incorporate Th, samples can contain impurities with relatively high Th contents. Initial 230Th/232Th is commonly estimated by assuming a source with bulk-Earth U/Th values in a state of secular equilibrium in the 238U-decay chain. The uncertainty in this 230Th/232Th estimate is also assumed, typically at +/-100%. Both assumptions contribute to uncertainty in ages determined for young speleothems. If the amount of initial detrital 230Th can be better quantified for samples or sites, then U-series ages will have smaller uncertainties and more precisely define the time series of climate proxies. This study determined the initial 230Th/232Th of modern calcite to provide more precise dates for central Texas speleothems. Calcite was grown on glass-plate substrates placed under active drips in central Texas caves. The 230Th/232Th of this modern calcite was determined using thermal ionization mass spectrometry. Results show that: 1) initial 230Th/232Th ratios can be accurately determined in these young samples and 2) measuring 230Th/232Th reduces the uncertainties in previously-determined ages on stalagmites from under the same drips. For example, measured initial 230Th/232Th in calcite collected on substrates from different locations in the cave at Westcave Preserve are 15.3 × 0.67 ppm, 14.6 × 0.83 ppm, 5.8 × 0.56 ppm, and 5.9 × 0.60 ppm, which are higher and more precise than the value commonly assumed for initial 230Th/232Th, 4.4 × 4.4 ppm. Soil sampled above Westcave, a potential source of detrital Th incorporated into speleothems, also has a high calculated 230Th/232Th. We calculate soil 230Th/232Th from measured U and Th concentrations of soil leachates (using DI water and ammonium acetate). Calculated 230Th/232Th for Westcave soils range from 0.39 to 28.4 ppm, which encompasses the range of initial 230Th/232Th values found in the modern calcite. Soil leachates from Natural Bridge Caverns and Inner Space Cavern were analyzed by the same method, yielding calculated 230Th/232Th ranging from 1.5 to 12.6 ppm (Natural Bridge), and from 1.43 to 272 ppm (Inner Space). Soil and calcite data indicate that the commonly assumed initial 230Th/232Th is not always applicable and that initial 230Th/232Th can be estimated more accurately by measuring Th isotope ratios in modern calcite and soils to determine speleothem U-series ages.

Fabrication of graphene/Fe3O4@polythiophene nanocomposite and its application in the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples.

PubMed

Mehdinia, Ali; Khodaee, Nader; Jabbari, Ali

2015-04-08

Polythiophene (PT) was used as a surface modifier of graphene/Fe3O4 (G/Fe3O4) composite to increase merit of it, and also overcome some limitations and disadvantages of using G/Fe3O4 alone as solid phase extraction (SPE) sorbent. An in-situ chemical polymerization method was employed to prepare G/Fe3O4@PT nanocomposites. Application of this newly designed material in the magnetic SPE (MSPE) of polycyclic aromatic hydrocarbons (PAHs), as model analytes, in the environmental water samples was investigated. The characterization of the hybrid material was performed using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform-infrared (FT-IR) spectroscopy and vibrating sample magnetometry. Seven important parameters, affecting the extraction efficiency of PAHs, including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent, initial sample volume and salt content of the sample were evaluated. The optimum extraction conditions were obtained as: 4 min for extraction time, 20 mg for sorbent amount, 100mL for initial sample volume, toluene as desorption solvent, 0.6 mL for desorption solvent volume, 6 min for desorption time and 30% (w/v) for NaCl concentration. Good performance data were obtained at the optimized conditions. Detection limits were in the range of 0.009-0.020 μg L(-1) in the real matrix. The calibration curves were linear over the concentration ranges from 0.03 to 80 μg L(-1) with correlation coefficients (R(2)) between 0.995 and 0.998 for all the analytes. Relative standard deviations were ranged from 4.3 to 6.3%. Appropriate recovery values, in the range of 83-107%, were also obtained for the real sample analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Roles of Long and Short Replication Initiation Proteins in the Fate of IncP-1 Plasmids

PubMed Central

Yano, Hirokazu; Deckert, Gail E.; Rogers, Linda M.

2012-01-01

Broad-host-range IncP-1 plasmids generally encode two replication initiation proteins, TrfA1 and TrfA2. TrfA2 is produced from an internal translational start site within trfA1. While TrfA1 was previously shown to be essential for replication in Pseudomonas aeruginosa, its role in other bacteria within its broad host range has not been established. To address the role of TrfA1 and TrfA2 in other hosts, efficiency of transformation, plasmid copy number (PCN), and plasmid stability were first compared between a mini-IncP-1β plasmid and its trfA1 frameshift variant in four phylogenetically distant hosts: Escherichia coli, Pseudomonas putida, Sphingobium japonicum, and Cupriavidus necator. TrfA2 was sufficient for replication in these hosts, but the presence of TrfA1 enhanced transformation efficiency and PCN. However, TrfA1 did not contribute to, and even negatively affected, long-term plasmid persistence. When trfA genes were cloned under a constitutive promoter in the chromosomes of the four hosts, strains expressing either both TrfA1 and TrfA2 or TrfA1 alone, again, generally elicited a higher PCN of an IncP1-β replicon than strains expressing TrfA2 alone. When a single species of TrfA was produced at different concentrations in E. coli cells, TrfA1 maintained a 3- to 4-fold higher PCN than TrfA2 at the same TrfA concentrations, indicating that replication mediated by TrfA1 is more efficient than that by TrfA2. These results suggest that the broad-host-range properties of IncP-1 plasmids are essentially conferred by TrfA2 and the intact replication origin alone but that TrfA1 is nonetheless important to efficiently establish plasmid replication upon transfer into a broad range of hosts. PMID:22228734

Retrospective evaluation of the effects of administration of tetrastarch (hydroxyethyl starch 130/0.4) on plasma creatinine concentration in dogs (2010-2013): 201 dogs.

PubMed

Yozova, Ivayla D; Howard, Judith; Adamik, Katja-Nicole

2016-07-01

To determine changes in creatinine concentrations following the administration of 6% tetrastarch (hydroxyethyl starch [HES] 130/0.4) compared to crystalloids (CRYSs) in critically ill dogs. Retrospective case series (2010-2013). University teaching hospital. Two hundred and one dogs admitted to the intensive care unit with initial plasma creatinine concentrations not exceeding laboratory reference intervals (52-117 μmol/L [0.6-1.3 mg/dL]) and receiving either CRYSs alone (CRYS group, n = 115) or HES with or without CRYSs (HES group, n = 86) for at least 24 hours. None. Creatinine concentrations at admission to the intensive care unit (T0), and 2-13 days (T1) and 2-12 weeks (T2) after initiation of fluid therapy were analyzed. Creatinine concentrations were analyzed as absolute values and as the maximum percentage change from T0 to T1 (T1max%) and from T0 to T2 (T2max%), respectively. Creatinine concentrations were available for 192 dogs during T1 and 37 dogs during T2. The median cumulative dose of HES was 86 mL/kg (range, 12-336 mL/kg). No difference was detected between the groups for age, gender, body weight, and length of hospitalization. Outcome was significantly different between the HES (66% survived) and the CRYS (87% survived) groups (P = 0.014). No significant difference was detected between groups for creatinine concentrations at T0, T1, T2, T1max%, or T2max%. No significant difference was detected between the groups for T1max% creatinine in dogs subclassified as having systemic inflammatory response syndrome or sepsis. HES administration in this canine population did not result in increased creatinine concentrations compared to administration of CRYSs. Further studies are needed to establish the safety of HES in critically ill dogs. © Veterinary Emergency and Critical Care Society 2016.

Preferrential Concentration of Particles in Protoplanetary Nebula Turbulence

NASA Technical Reports Server (NTRS)

Hartlep, Thomas; Cuzzi, Jeffrey N.

2015-01-01

Preferential concentration in turbulence is a process that causes inertial particles to cluster in regions of high strain (in-between high vorticity regions), with specifics depending on their stopping time or Stokes number. This process is thought to be of importance in various problems including cloud droplet formation and aerosol transport in the atmosphere, sprays, and also in the formation of asteroids and comets in protoplanetary nebulae. In protoplanetary nebulae, the initial accretion of primitive bodies from freely-floating particles remains a problematic subject. Traditional growth-by-sticking models encounter a formidable "meter-size barrier" [1] in turbulent nebulae. One scenario that can lead directly from independent nebula particulates to large objects, avoiding the problematic m-km size range, involves formation of dense clumps of aerodynamically selected, typically mm-size particles in protoplanetary turbulence. There is evidence that at least the ordinary chondrite parent bodies were initially composed entirely of a homogeneous mix of such particles generally known as "chondrules" [2]. Thus, while it is arcane, turbulent preferential concentration acting directly on chondrule size particles are worthy of deeper study. Here, we present the statistical determination of particle multiplier distributions from numerical simulations of particle-laden isotopic turbulence, and a cascade model for modeling turbulent concentration at lengthscales and Reynolds numbers not accessible by numerical simulations. We find that the multiplier distributions are scale dependent at the very largest scales but have scale-invariant properties under a particular variable normalization at smaller scales.

Off-pump coronary bypass surgery adversely affects alveolar gas exchange.

PubMed

Gasparović, Hrvoje; Unić, Daniel; Sutlić, Zeljko; Husedzinović, Ino; Biocina, Bojan; Rudez, Igor; Nikić, Nada; Jelić, Ivan

2008-03-01

While the introduction of off-pump myocardial revascularization (OPCAB) has initially shown promise in reducing respiratory complications inherent to conventional coronary surgery, it has failed to eradicate them. Our study focused on quantifying the lactate release from the lungs and the dysfunction at the level of the alveolar-capillary membrane precipitated by OPCAB at different time points after the insult. Furthermore, we aimed to determine the impact of pulmonary lactate production on systemic lactic acid concentrations. The study was conducted in a prospective observational fashion. Forty consecutive patients undergoing OPCAB were analyzed. The mean patient age was 60 +/- 10 years. The mean EUROScore was 3.8 +/- 2.9. The alveolar-arterial O2 gradient increased from 19 [range 9 to 30] to 26 [range 20 to 34] kPa (P < 0.001) and remained elevated up to 6 hours after surgery. It rapidly declined again by 18 hours postoperatively. The observed increase in the pulmonary lactate release (PLR) from a baseline value of 0.022 [range -0.074 to 0.066] to 0.089 [range 0.016 to 0.209] mmol/min/m2 at six hours postoperatively did not reach statistical significance (P = 0.105). The systemic arterial lactate (Ls) concentration increased from 0.94 [range 0.78 to 1.06] to 1.39 [range 0.97 to 2.81] mmol/L (P < 0.001). The venoarterial pCO2 difference showed no significant change in comparison to baseline values. The mortality in the studied group was 2.5% (1/40). The pulmonary lactate production showed a statistically significant correlation with the systemic lactate concentration (R = 0.46; P = 0.003). Pulmonary injury following off pump myocardial revascularization was evidenced by a prompt increase in the alveolar-arterial oxygen gradient. The alveolar-arterial O2 gradient correlated with the duration of mechanical ventilation.

Effects of chronic copper exposure on development and survival in the southern leopard frog (Lithobates [Rana] sphenocephalus).

PubMed

Lance, Stacey L; Erickson, Matthew R; Flynn, R Wesley; Mills, Gary L; Tuberville, Tracey D; Scott, David E

2012-07-01

Exposure to environmental contaminants contributes to the global decline of amphibian populations. The impacts of organic contaminants on amphibians are well documented. However, substantially less is known concerning the potential effects of metals on amphibian populations. Copper (Cu) is an essential element, but it can be toxic at concentrations only slightly higher than the normal physiological range. The present study examines the effects of chronic Cu exposure on embryos and larvae of southern leopard frogs, Lithobates (Rana) sphenocephalus. Groups of eggs from multiple clutches were collected from two wetlands and exposed to a range of Cu concentrations (0-150 µg/L) until they reached the free-swimming stage, and then individual larvae were reared to metamorphosis. Higher Cu concentrations significantly reduced embryo survival to the free-swimming stage but did not further reduce survival to metamorphosis. Larval period was affected by Cu treatment, but the clutch from which larvae originated (i.e., parentage) explained a higher proportion of the variation. Embryo survival to hatching varied significantly among clutches, ranging from 42.9 to 79.2%. Measurable levels of Cu were found in larvae with body burdens up to 595 µg Cu/g dry mass in the 100 µg/L treatment, and larval Cu body burdens were higher than in metamorphs. The present study also demonstrated that higher initial egg density ameliorated embryo mortality at higher Cu levels and should be accounted for in future studies. Copyright © 2012 SETAC.

Effects of removing Good Hope Mill Dam on selected physical, chemical, and biological characteristics of Conodoguinet Creek, Cumberland County, Pennsylvania

USGS Publications Warehouse

Chaplin, Jeffrey J.; Brightbill, Robin A.; Bilger, Michael D.

2005-01-01

The implications of dam removal on channel characteris-tics, water quality, benthic invertebrates, and fish are not well understood because of the small number of removals that have been studied. Comprehensive studies that document the effects of dam removal are just beginning to be published, but most research has focused on larger dams or on the response of a sin-gle variable (such as benthic invertebrates). This report, pre-pared in cooperation with the Conodoguinet Creek Watershed Association, provides an evaluation of how channel morphol-ogy, bed-particle-size distribution, water quality, benthic inver-tebrates, fish, and aquatic habitat responded after removal of Good Hope Mill Dam (a small 'run of the river' dam) from Conodoguinet Creek in Cumberland County, Pa. Good Hope Mill Dam was a 6-foot high, 220-foot wide concrete structure demolished and removed over a 3-day period beginning with the initial breach on November 2, 2001, at 10:00 a.m. eastern standard time. To isolate the effects of dam removal, data were collected before and after dam removal at five monitoring stations and over selected reaches upstream, within, and downstream of the impoundment. Stations 1, 2, and 5 were at free-flowing control locations 4.9 miles upstream, 2.5 miles upstream, and 5 miles downstream of the dam, respec-tively. Stations 3 and 4 were located where the largest responses were anticipated, 115 feet upstream and 126 feet downstream of the dam, respectively Good Hope Mill Dam was not an effective barrier to sedi-ment transport. Less than 3 inches of sediment in the silt/clay-size range (less than 0.062 millimeters) coated bedrock within the 7,160-foot (1.4-mile) impoundment. The bedrock within the impoundment was not incised during or after dam removal, and the limited sediment supply resulted in no measurable change in the thalweg elevation downstream of the dam. The cross-sec-tional areas at stations 3 and 4, measured 17 days and 23 months after dam removal, were within 3 percent of the area measured before removal. Some of the impounded silt/clay at station 3 and other sed-iment in the work area downstream of the dam were initially entrained over the 3-day removal period and deposited on sub-strate at station 4. Remaining silt/clay at station 3 and deposits at station 4 were transported downstream by the flows mea-sured over the 23 months after removal (daily mean flow ranged from 38 to 5,180 cubic feet per second). The median bed-parti-cle size at station 3 increased by approximately 32 millimeters in the 23-month period after removal. Bed-particle-size distri-bution at station 4 became finer when silt/clay was initially deposited but coarsened as high flows flushed it downstream; median bed-particle size was 77.7 millimeters before removal compared to 31.3 millimeters 17 days after removal and 99 mil-limeters 23 months after removal. Good Hope Mill Dam had either no effect on water-quality characteristics or the effect was so small it was masked by sea-sonal and periodic variability. Measurements of daily mean temperature, dissolved-oxygen concentration, pH, and specific conductance on a short time scale (every 15 minutes) indicate the daily range of temperature was suppressed under impounded conditions and daily extremes of temperature, dis-solved-oxygen concentration, pH, and specific conductance at station 2 were out of phase by approximately 12 hours with station 3. Once the dam was removed, the pattern at station 3 shifted and converged with the pattern at station 2. The offset before removal may be related to a lag time resulting from a decrease in velocity through the impoundment. Total nitrogen and suspended-sediment concentrations increased upon the initial dam breach but were within the range of concentrations measured from March 2001 through April 2002 over varying flow conditions at station 1. Total nitrogen concentration at station 4 was 4.66 milligrams per liter upon the initial breach of the dam,

Water-Quality Data for Selected National Park Units within the Southern Colorado Plateau Network, Arizona, Utah, Colorado, and New Mexico, Water Years 2005 and 2006

USGS Publications Warehouse

Macy, Jamie P.; Monroe, Stephen A.

2006-01-01

The National Park Service initiated a Level 1 Water-Quality Inventory program to provide water-quality data to park managers so informed natural resource management decisions could be made. Level 1 water-quality data were collected by the U.S. Geological Survey Arizona Water Science Center at 57 sites in 13 National Park units located in the Southern Colorado Plateau Inventory and Monitoring network in water years 2005 and 2006. These data describe the current water-quality at selected sites within the park units and provide information for monitoring future trends. Water samples were collected three times at each type of site including wells, springs, seeps, tinajas, rivers, a lake, and an irrigation ditch. Field measurements were taken at each site and they included pH, specific conductance, temperature, barometric pressure, dissolved oxygen, alkalinity, turbidity, and discharge rates where applicable. Water samples collected were sent to the U.S. Geological Survey National Water Quality Laboratory and analyzed for major ions, trace elements, and nutrients. The National Water Quality Laboratory also analyzed selected samples for mercury and petroleum hydrocarbons. Additional samples at selected sites were collected and analyzed for cyanide, radiochemistry, and suspended sediment by U.S. Geological Survey contract labs. Fecal-indicator bacteria (Escherichia coli) were sampled for at selected sites as another indicator of water quality. Quality control for this study was achieved through proper training of field personnel, use of standard U.S. Geological Survey field and laboratory protocols, collection of sample blanks and replicates, and a thorough review of the water-quality analyses. Measured field pH ranged from 6.0 to 8.8, within normal range for springs and rivers, at most sites. Concentrations of dissolved solids ranged from 48 to 8,680 mg/L and the majority of samples had concentrations of dissolved solids below 900 mg/L. Trace-element concentrations at most sites were at or near the laboratory reporting levels. The highest overall trace-element concentrations were found at U.S. Highway 160 Spring near Park Entrance to Mesa Verde National Park. Concentrations of uranium in samples at all sites ranged from below the detection limit to 55.7 ?g/L. Water samples from selected sites were analyzed for total petroleum hydrocarbons and concentrations of total petroleum hydrocarbons were at or above the laboratory detection limit in samples at six National Park units. Ten sites were sampled for Escherichia coli and positive counts were found at 9 out of the ten sites, the highest colony counts were found at Chinle Creek at Chinle, AZ in Canyon de Chelly National Monument. Measured concentrations of dissolved ammonia, nitrite, and nitrate were at or near laboratory reporting levels at most sites; nitrate concentrations ranged from below the reporting limit (0.047 mg/L) to 9.77 mg/L. Samples that were analyzed for mercury had concentrations below or at the laboratory reporting level. Concentrations of cyanide were less than the laboratory reporting level for all samples except two, Spruce Tree House Spring in Mesa Verde National Park and Pine Tree Canyon Tinaja in Canyon de Chelly National Monument, which had average concentrations of .042 and .011 ?g/L respectively. Gross alpha/beta radioactivity counts were below the U.S. Environmental Protection Agency maximum contaminant level except for samples from Casa Chiquita Well Middle at Chaco Culture National Historical Park which averaged 35 pCi/L. Suspended-sediment concentrations were variable and ranged from 10 to 150,000 mg/L.

Sol concentration effect on ZnO nanofibers photocatalytic activity synthesized by sol-gel dip coating method

NASA Astrophysics Data System (ADS)

Toubane, M.; Tala-Ighil, R.; Bensouici, F.; Bououdina, M.; Souier, M.; Liu, S.; Cai, W.; Iratni, A.

2017-03-01

ZnO thin films were deposited onto glass substrate by sol-gel dip coating method. The initial sol concentrations were varied from 0.2 to 0.5 M. Zinc acetate dihydrate, ethanol and Diethanolamine (DEA) were used as staring material, solvent and stabilizer respectively. The evolution of structural, optical properties and methylene blue (MB) photodegradation of the as-deposited films on sol concentration was investigated. Rietveld refinements of x-ray patterns reveal that all the as-prepared thin films have a Zincite-type structure with grain orientation along to c-axis. The strongest sol concentration is favorable for the highest crystallization quality. However, the high preferred orientation factor (POF) occurs for 0.3 M sol concentration. The field emission scanning electron microscopy observations reveals nanofibrous morphology with different lengths. The nanofibers density increases with increasing sols concentrations until forming a flower-like morphology. The EDS analysis confirms the high purity of the as-deposited ZnO films. It is found that all films present good transparency greater than 95% in the visible range; the optical band gap is slightly reduced with the increase in sol concentration. The photocatalytic degradation is enhanced by 90% with the sol concentration. The K app rate reaction increased with increasing sol concentration. The films stability is found to slightly decrease after the third cycle, especially for 0.5 M sol concentration.

Co-composting of two-phase olive-mill pomace and poultry manure with tomato harvest stalks.

PubMed

Sülük, Kemal; Tosun, İsmail; Ekinci, Kamil

2017-04-01

In this study, two-phase olive-mill pomace with poultry manure and chopped tomato harvest stalks were composted at different initial carbon/nitrogen (C/N) ratios with fixed free air space of 35%. Composting experiment was carried out in the 15 aerobic reactors made of stainless steel and was monitored for 28 days. During the composting process, temperature, moisture content, organic matter (OM), pH, electrical conductivity, oxygen and carbon dioxide concentrations, total carbon, total nitrogen, ammonium nitrogen ([Formula: see text]), nitrate nitrogen ([Formula: see text]), and total phosphorus were monitored. Compost mass and volume changes were determined at the beginning, during remixings, and at the end of composting. While the stabilization period took less time for the mixtures containing a high amount of poultry manure, the mixtures having the high portion of two-phase olive-mill pomace took a longer time due to the structure of olive stone and its lignin content. Dry matter loss (range: 18.1-34.0%.) in the mixtures increased with an increase in the share of poultry manure and tomato stalks in the initial mixture. OM loss (range: 21.7-46.1%) for tomato stalks (measured separately) during composting increased due to an increase in the ratio of poultry manure in the initial mixtures.

Effect of infusion pump fill-stroke flow interruption on response to sodium nitroprusside in surgical patients.

PubMed

Mann, H J; Fuhs, D W; Cerra, F B

1988-03-01

The influence of the piston-cassette pump fill stroke on the pharmacodynamic response to sodium nitroprusside was evaluated prospectively in 10 adult patients in the surgical intensive-care unit. Simultaneous analog recordings of blood pressure and fill stroke were made over three complete pump fill cycles in each patient. Sodium nitroprusside flow rates and concentrations were recorded throughout the data-collection period. Analysis was based on the maximum pressure obtained during the two-minute baseline period before a fill stroke (Pmax baseline), the pressure at the initiation of the fill stroke (P initial), and the maximum pressure obtained during the two-minute period after the fill stroke (Pmax postfill). The maximum systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) during the baseline and post-fill-stroke periods were significantly different. The mean (+/- S.D.) variability in pressure between the time periods Pmax baseline and Pmax postfill was 3.9 +/- 5.8 mm Hg for SBP (range, -8 to +16), 3.5 +/- 5.7 mm Hg for DBP (range, -7 to +13), and 3.6 +/- 5.6 mm Hg for MBP (range, -7 to +14). The likelihood of a pharmacodynamic change was inconsistent both between and within patients. Within patients the difference between cycles for the variability between time periods ranged from a minimum of 2 mm Hg to a maximum of 16 mm Hg for SBP, 2 mm Hg to 17 mm Hg for DBP, and 1 mm Hg to 17 mm Hg for MBP. The variability within the baseline period (Pmax baseline - P initial) in SBP was significantly greater than the variability between the time periods, while the differences for DBP and MBP were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

A survey of emerging contaminants in the estuarine receiving environment around Auckland, New Zealand.

PubMed

Stewart, Michael; Olsen, Greg; Hickey, Christopher W; Ferreira, Bianca; Jelić, Aleksandra; Petrović, Mira; Barcelo, Damia

2014-01-15

Increasing urbanisation in the future will put mounting stresses on the receiving environments around those urban centres due to increased sedimentation and contaminant runoff. Emerging contaminants (ECs) are an extensive array of chemicals and many are not under regulatory action. Within New Zealand likely future pressures from ECs will be in both urban centres and rural areas due to intensive agriculture, although at present there is a lack of information on the state of the environment in both sectors. This study was initiated to gauge the distribution of ECs in the urban environment by measuring concentrations of flame retardants, plasticisers, alkylphenols, herbicides and pesticides, steroid oestrogens, pharmaceuticals and heavy metals in sediment from 13 estuarine sites around Auckland, New Zealand's biggest city. Total polybrominated diphenyl ether (PBDE) flame retardant concentrations ((7)ΣPBDE) ranged from 0.55 to 573 ng/g (dw). The phthalate plasticiser di(2-ethylhexyl)phthalate (DEHP) was measured at up to 11,500 ng/g from one site. Nonylphenol (NP) was found at up to 32,000 ng/g at one site adjacent to the city's major wastewater treatment plant (WWTP). However, median concentrations of NP were 153 ng/g, suggesting this site was not representative of the region. Nonylphenol mono- and di-ethoxylates (NPEO1,2) had highest concentrations (1600 ng/g) at a marina. Highest glyphosate concentrations (up to 950 ng/g) were observed at residential sites. Steroid oestrogens were detected at extremely low concentrations (maximum 2.2 ng/g), while all other pesticides or herbicides were not detected at any sites. Multi-residue analysis of 46 pharmaceuticals showed presence of 21 compounds at one or more sites, with average concentrations ranging from 0.16 to 7.66 ng/g. Generally, environmental concentrations of ECs were similar to those reported world-wide. However, comparisons for pharmaceuticals were problematic, due to very few studies on pharmaceutical concentrations in estuarine sediments, with most focussed on sewage and stream water phases. © 2013.

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

Meharg, A.A.; Shore, R.F.; Broadgate, K.

The toxicity and accumulation of arsenate was determined in the earthworm Lumbricus terrestris in soil from different layers of a forest profile. Toxicity increased fourfold between 2 and 10 d. Edaphic factors (pH, soil organic matter, and depth in soil profile) also affected toxicity with a three fold decrease in the concentration that causes 50% mortality with increasing depth in soil. In a 4-d exposure study, there was no evidence of arsenic bioconcentration in earthworm tissue, although bioaccumulation was occurring. There was a considerable difference in tissue residues between living and dead earthworms, with dead worms having higher concentrations. Thismore » difference was dependent on both soil arsenate concentration and on soil type. Over a wide range of soil arsenate concentrations, earthworm arsenic residues are homeostatically maintained in living worms, but this homeostasis breaks down during death. Alternatively, equilibration with soil residues may occur via accumulation after death. In long-term accumulation studies in soils dosed with a sublethal arsenate concentration, bioconcentration of arsenate did not occur until day 12, after which earthworm concentrations rose steadily above the soil concentration, with residues in worms three fold higher than soil concentrations by the termination of the study. This bioconcentration only occurred in depurated worms over the time period of the study. Initially, depurated worms had lower arsenic concentrations than undepurated until tissue concentrations were equivalent to the soil concentration. Once tissue concentration was greater than soil concentration, depurated worms had higher arsenic residues than undepurated.« less

Glycine's radiolytic destruction in ices: first in situ laboratory measurements for Mars.

PubMed

Gerakines, Perry A; Hudson, Reggie L

2013-07-01

We report new laboratory studies of the radiation-induced destruction of glycine-containing ices for a range of temperatures and compositions that allow extrapolation to martian conditions. In situ infrared spectroscopy was used to study glycine decay rates as a function of temperature (from 15 to 280 K) and initial glycine concentrations in six mixtures whose compositions ranged from dry glycine to H2O+glycine (300:1). Results are presented in several systems of units, with cautions concerning their use. The half-life of glycine under the surface of Mars is estimated as an extrapolation of this data set to martian conditions, and trends in decay rates are described as are applications to Mars' near-surface chemistry.

Evaluation of on-line concentration coupled to liquid chromatography tandem mass spectrometry for the quantification of neonicotinoids and fipronil in surface water and tap water.

PubMed

Montiel-León, Juan Manuel; Duy, Sung Vo; Munoz, Gabriel; Amyot, Marc; Sauvé, Sébastien

2018-04-01

A study was initiated to investigate a fast and reliable method for the determination of selected systemic insecticides in water matrixes and to evaluate potential sources of bias in their analysis. Acetamiprid, clothianidin, desnitro-imidacloprid, dinotefuran, fipronil, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam were amenable to analysis via on-line sample enrichment hyphenated to ultra-high-performance liquid chromatography tandem mass spectrometry. The selection of on-line solid-phase extraction parameters was dictated by a multicriterion desirability approach. A 2-mL on-line injection volume with a 1500 μL min -1 loading flow rate met the objectives sought in terms of chromatographic requirements, extraction efficiency, sensitivity, and precision. A total analysis time of 8 min per sample was obtained with method limits of detection in the range of 0.1-5 ng L -1 for the scope of targeted analytes. Automation at the sample concentration step yielded intraday and interday precisions in the range of 1-23 and 2-26%, respectively. Factors that could affect the whole method accuracy were further evaluated in matrix-specific experiments. The impact of the initial filtration step on analyte recovery was evaluated in ultra-pure water, tap water, and surface water. Out of the nine membranes tested, glass fiber filters and polyester filters appeared as the most appropriate materials. Sample storage stability was also investigated across the three matrix types; the targeted analytes displayed suitable stability during 28 days at either 4 °C or - 20 °C, with little deviations (± 10%) with respect to the initial T 0 concentration. Method applicability was demonstrated in a range of tap water and surface water samples from the province of Québec, Canada. Results from the present survey indicated a predominance of thiamethoxam (< 0.5-10 and 3-61 ng L -1 in tap water and river water, respectively), clothianidin (< 0.5-6 and 2-88 ng L -1 in tap water and river water, respectively), and imidacloprid (< 0.1-1 and 0.8-38 ng L -1 in tap water and river water, respectively) among the targeted analytes. Graphical abstract ᅟ Development of solid-phase extraction coupled on-line to UHPLC-MS/MS for the rapid screening of systemic insecticides in water.

Isotopic and trace element variations in the Ruby Batholith, Alaska, and the nature of the deep crust beneath the Ruby and Angayucham Terranes

USGS Publications Warehouse

Arth, Joseph G.; Zmuda, Clara C.; Foley, Nora K.; Criss, Robert E.; Patton, W.W.; Miller, T.P.

1989-01-01

Thirty-six samples from plutons of the Ruby batholith of central Alaska were collected and analyzed for 22 trace elements, and many were analyzed for the isotopic compositions of Sr, Nd, O, and Pb in order to delimit the processes that produced the diversity of granodioritic to granitic compositions, to deduce the nature of the source of magmas at about 110 Ma, and to characterize the deep crust beneath the Ruby and Angayucham terranes. Plutons of the batholith show a substantial range in initial 87Sr/86Sr (SIR) of 0.7055–0.7235 and a general decrease from southwest to northeast. Initial 143Nd/144Nd (NIR) have a range of 0.51150–0.51232 and generally increase from southwest to northeast. The δ18O values for most whole rocks have a range of +8.4 to +11.8 and an average of +10.3‰. Rb, Cs, U, and Th show large ranges of concentration, generally increase as SiO2 increases, and are higher in southwest than in northeast plutons. Sr, Ba, Zr, Hf, Ta, Sc, Cr, Co, and Zr show large ranges of concentration and generally decrease as SiO2 increases. Rare earth elements (REE) show fractionated patterns and negative Eu anomalies. REE concentrations and anomalies are larger in the southwest than in the northeast plutons. Uniformity of SIR and NIR in Sithylemenkat and Jim River plutons suggests a strong role for fractional crystallization or melting of uniform magma sources at depth. Isotopic variability in Melozitna, Ray Mountains, Hot Springs, and Kanuti plutons suggests complex magmatic processes such as magma mixing and assimilation, probably combined with fractional crystallization, or melting of a complex source at depth. The large variations in SIR and NIR in the batholith require a variation in source materials at depth. The southwestern plutons probably had dominantly siliceous sources composed of metamorphosed Proterozoic and Paleozoic upper crustal rocks. The northeastern plutons probably had Paleozoic sources that were mixtures of siliceous and intermediate to mafic crustal rocks. The inferred sources could well have been the higher-metamorphic-grade lithologic equivalents of the exposed Proterozoic(?) to Paleozoic schists, orthogneisses, and metavolcanic rocks of Ruby terrane, the silicic portions of which are quite radiogenic. The deeper crustal sources that gave rise to most of the batholithic magmas are inferred to be similar under both the Ruby metamorphic terrane and the Angayucham ophiolitic terrane.

Enzyme immobilization on ultrafine cellulose fibers via poly(acrylic acid) electrolyte grafts.

PubMed

Chen, Hong; Hsieh, You-Lo

2005-05-20

Ultrafine cellulose fiber (diameter 200-400 nm) surfaces were grafted with polyacrylic acid (PAA) via either ceric ion initiated polymerization or methacrylation of cellulose with methacrylate chloride (MACl) and subsequent free-radical polymerization of acrylic acid. PAA grafts by ceric ion initiated polymerization increased with increasing reaction time (2-24 h), monomer (0.3-2.4 M), and initiator (1-10 mM) concentrations, and spanned a broad range from 5.5-850%. PAA grafts on the methacrylated cellulose fibers also increased with increasing molar ratios of MACl to cellulosic hydroxyl groups (MACl/OH, 2-6.4) and monomer acrylic acid (AA) to initiator potassium persulfate (KPS) ratios ([AA]/[KPS], 1.5-6), and were in a much narrower range between 12.8% and 29.4%. The adsorption of lipase (at 1 mg/ml lipase and pH 7) and the activity of adsorbed lipase (pH 8.5, 30 degrees C), in both cases decreased with increasing PAA grafts. The highest adsorption and activity of the lipase on the ceric ion initiated grafted fibers were 1.28 g/g PAA and 4.3 U/mg lipase, respectively, at the lowest grafting level of 5.5% PAA, whereas they were 0.33 g/g PAA and 7.1 U/mg lipase, respectively, at 12.8% PAA grafts on the methacrylated and grafted fibers. The properties of the grafted fibers and the absorption behavior and activity of lipase suggest that the PAA grafts are gel-like by ceric-initiated reaction and brush-like by methacrylation and polymerization. The adsorbed lipase on the ceric ion-initiated grafted surface possessed greatly improved organic solvent stability over the crude lipase. The adsorbed lipases exhibited 0.5 and 0.3 of the initial activity in the second and third assay cycles, respectively. (c) 2004 Wiley Periodicals, Inc.

Enhanced Furfural Yields from Xylose Dehydration in the gamma-Valerolactone/Water Solvent System at Elevated Temperatures.

PubMed

Sener, Canan; Motagamwala, Ali Hussain; Alonso, David Martin; Dumesic, James

2018-05-18

High yields of furfural (>90%) were achieved from xylose dehydration in a sustainable solvent system composed of -valerolactone (GVL), a biomass derived solvent, and water. It is identified that high reaction temperatures (e.g., 498 K) are required to achieve high furfural yield. Additionally, it is shown that the furfural yield at these temperatures is independent of the initial xylose concentration, and high furfural yield is obtained for industrially relevant xylose concentrations (10 wt%). A reaction kinetics model is developed to describe the experimental data obtained with solvent system composed of 80 wt% GVL and 20 wt% water across the range of reaction conditions studied (473 - 523 K, 1-10 mM acid catalyst, 66 - 660 mM xylose concentration). The kinetic model demonstrates that furfural loss due to bimolecular condensation of xylose and furfural is minimized at elevated temperature, whereas carbon loss due to xylose degradation increases with increasing temperature. Accordingly, the optimal temperature range for xylose dehydration to furfural in the GVL/H2O solvent system is identified to be from 480 to 500 K. Under these reaction conditions, furfural yield of 93% is achieved at 97% xylan conversion from lignocellulosic biomass (maple wood). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Developing and applying metamodels of high resolution ...

EPA Pesticide Factsheets

As defined by Wikipedia (https://en.wikipedia.org/wiki/Metamodeling), “(a) metamodel or surrogate model is a model of a model, and metamodeling is the process of generating such metamodels.” The goals of metamodeling include, but are not limited to (1) developing functional or statistical relationships between a model’s input and output variables for model analysis, interpretation, or information consumption by users’ clients; (2) quantifying a model’s sensitivity to alternative or uncertain forcing functions, initial conditions, or parameters; and (3) characterizing the model’s response or state space. Using five existing models developed by US Environmental Protection Agency, we generate a metamodeling database of the expected environmental and biological concentrations of 644 organic chemicals released into nine US rivers from wastewater treatment works (WTWs) assuming multiple loading rates and sizes of populations serviced. The chemicals of interest have log n-octanol/water partition coefficients ( ) ranging from 3 to 14, and the rivers of concern have mean annual discharges ranging from 1.09 to 3240 m3/s. Log linear regression models are derived to predict mean annual dissolved and total water concentrations and total sediment concentrations of chemicals of concern based on their , Henry’s Law Constant, and WTW loading rate and on the mean annual discharges of the receiving rivers. Metamodels are also derived to predict mean annual chemical

An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

PubMed Central

Starliper, Clifford E.; Ketola, Henry G.; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc A.; Dittman, Dawn E.

2014-01-01

Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02–0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate. PMID:25685547

An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

USGS Publications Warehouse

Starliper, Clifford E.; Ketola, H. George; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc; Dittman, Dawn E.

2015-01-01

Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02–0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate.

An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

USGS Publications Warehouse

Starliper, Clifford E.; Ketolab, Henry G.; Noyes, Andrew D.; Schill, William B.; Henson, Fred G.; Chalupnicki, Marc A.; Dittman, Dawn E.

2015-01-01

Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments for captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine if selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBC’s (0.02 to 0.04%) were obtained with three different sources of cinnamon oil. MBC’s for three sources of oregano and lemongrass oils ranged from 0.14 to 0.30% and 0.10 to 0.65%, respectively, and for two thyme oils were 2.11 and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBC’s to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBC’s for all but one isolate

Modelling compressible dense and dilute two-phase flows

NASA Astrophysics Data System (ADS)

Saurel, Richard; Chinnayya, Ashwin; Carmouze, Quentin

2017-06-01

Many two-phase flow situations, from engineering science to astrophysics, deal with transition from dense (high concentration of the condensed phase) to dilute concentration (low concentration of the same phase), covering the entire range of volume fractions. Some models are now well accepted at the two limits, but none are able to cover accurately the entire range, in particular regarding waves propagation. In the present work, an alternative to the Baer and Nunziato (BN) model [Baer, M. R. and Nunziato, J. W., "A two-phase mixture theory for the deflagration-to-detonation transition (DDT) in reactive granular materials," Int. J. Multiphase Flow 12(6), 861 (1986)], initially designed for dense flows, is built. The corresponding model is hyperbolic and thermodynamically consistent. Contrarily to the BN model that involves 6 wave speeds, the new formulation involves 4 waves only, in agreement with the Marble model [Marble, F. E., "Dynamics of a gas containing small solid particles," Combustion and Propulsion (5th AGARD Colloquium) (Pergamon Press, 1963), Vol. 175] based on pressureless Euler equations for the dispersed phase, a well-accepted model for low particle volume concentrations. In the new model, the presence of pressure in the momentum equation of the particles and consideration of volume fractions in the two phases render the model valid for large particle concentrations. A symmetric version of the new model is derived as well for liquids containing gas bubbles. This model version involves 4 characteristic wave speeds as well, but with different velocities. Last, the two sub-models with 4 waves are combined in a unique formulation, valid for the full range of volume fractions. It involves the same 6 wave speeds as the BN model, but at a given point of space, 4 waves only emerge, depending on the local volume fractions. The non-linear pressure waves propagate only in the phase with dominant volume fraction. The new model is tested numerically on various test problems ranging from separated phases in a shock tube to shock-particle cloud interaction. Its predictions are compared to BN and Marble models as well as against experimental data showing clear improvements.

A novel additive for the reduction of acid gases and NO(x) in municipal waste incinerator flue gas.

PubMed

Hall, William J; Williams, Paul T

2006-08-01

The reduction of SO2, HCl, and NO(x) concentrations using calcium magnesium acetate (CMA) as a novel sorbent in a simulated municipal waste incinerator flue gas was investigated. The reduction of individual SO2, HCl, and NO(x) concentrations was tested at 850 degrees C and it was found that CMA could reduce the SO2 concentration by 74%, HCl concentration by 64%, or NO(x) concentration by 94%. It was observed that individual SO2 or HCl capture increased with increasing initial oxygen concentration in the reacting gas or increasing sorbent input. NO(x) reduction decreased with increasing initial oxygen concentration in the reacting gas. The simultaneous reduction of SO2, HCl, and NO(x) concentrations by CMA was also investigated. It was found that CMA could simultaneously capture 60% SO2 and 61% HCl and reduce NO(x) concentrations by 26%, when the initial oxygen concentration in the reacting gas was 4%. During the simultaneous reduction of SO2, HCl, and NO(x), it was noted that as the initial oxygen concentration in the reacting gas increased, the efficiency of SO2 capture increased too, but the efficiency of HCl capture and the efficiency of NO(x) destruction decreased.

Radionuclide sorption in Yucca Mountain tuffs with J-13 well water: Neptunium, uranium, and plutonium. Yucca Mountain site characterization program milestone 3338

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

Triay, I.R.; Cotter, C.R.; Kraus, S.M.

1996-08-01

We studied the retardation of actinides (neptunium, uranium, and plutonium) by sorption as a function of radionuclide concentration in water from Well J-13 and of tuffs from Yucca Mountain. Three major tuff types were examined: devitrified, vitric, and zeolitic. To identify the sorbing minerals in the tuffs, we conducted batch sorption experiments with pure mineral separates. These experiments were performed with water from Well J-13 (a sodium bicarbonate groundwater) under oxidizing conditions in the pH range from 7 to 8.5. The results indicate that all actinides studied sorb strongly to synthetic hematite and also that Np(V) and U(VI) do notmore » sorb appreciably to devitrified or vitric tuffs, albite, or quartz. The sorption of neptunium onto clinoptilolite-rich tuffs and pure clinoptilolite can be fitted with a sorption distribution coefficient in the concentration range from 1 X 10{sup -7} to 3 X 10{sup -5} M. The sorption of uranium onto clinoptilolite-rich tuffs and pure clinoptilolite is not linear in the concentration range from 8 X 10{sup -8} to 1 X 10{sup -4} M, and it can be fitted with nonlinear isotherm models (such as the Langmuir or the Freundlich Isotherms). The sorption of neptunium and uranium onto clinoptilolite in J-13 well water increases with decreasing pH in the range from 7 to 8.5. The sorption of plutonium (initially in the Pu(V) oxidation state) onto tuffs and pure mineral separates in J-13 well water at pH 7 is significant. Plutonium sorption decreases as a function of tuff type in the order: zeolitic > vitric > devitrified; and as a function of mineralogy in the order: hematite > clinoptilolite > albite > quartz.« less

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant, USA.

PubMed

Fox, P; Narayanaswamy, K; Genz, A; Drewes, J E

2001-01-01

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant (NWWRP) were evaluated by sampling a network of groundwater monitoring wells located within the reclaimed water plume. The Mesa Northwest Water Reclamation Plant has used soil aquifer treatment (SAT) since it began operation in 1990 and the recovery of reclaimed water from the impacted groundwater has been minimal. Groundwater samples obtained represent travel times from several days to greater than five years. Samples were analyzed for a wide range of organic and inorganic constituents. Sulfate was used as a tracer to estimate travel times and define reclaimed water plume movement. Dissolved organic carbon concentrations were reduced to approximately 1 mg/L after 12 to 24 months of soil aquifer treatment with an applied DOC concentration from the NWWRP of 5 to 7 mg/L. The specific ultraviolet absorbance (SUVA) increased during initial soil aquifer treatment on a time-scale of days and then decreased as longer term soil aquifer treatment removed UV absorbing compounds. The trihalomethane formation potential (THMFP) was a function of the dissolved organic carbon concentration and ranged from 50 to 65 micrograms THMFP/mg DOC. Analysis of trace organics revealed that the majority of trace organics were removed as DOC was removed with the exception of organic iodine. The majority of nitrogen was applied as nitrate-nitrogen and the reclaimed water plume had lower nitrate-nitrogen concentrations as compared to the background groundwater. The average dissolved organic carbon concentrations in the reclaimed water plume were less than 50% of the drinking water dissolved organic concentrations from which the reclaimed water originated.

Exogenous thyrotoxicosis in dogs attributable to consumption of all-meat commercial dog food or treats containing excessive thyroid hormone: 14 cases (2008-2013).

PubMed

Broome, Michael R; Peterson, Mark E; Kemppainen, Robert J; Parker, Valerie J; Richter, Keith P

2015-01-01

To describe findings in dogs with exogenous thyrotoxicosis attributable to consumption of commercially available dog foods or treats containing high concentrations of thyroid hormone. Retrospective and prospective case series. 14 dogs. Medical records were retrospectively searched to identify dogs with exogenous thyrotoxicosis attributable to dietary intake. One case was found, and subsequent cases were identified prospectively. Serum thyroid hormone concentrations were evaluated before and after feeding meat-based products suspected to contain excessive thyroid hormone was discontinued. Scintigraphy was performed to evaluate thyroid tissue in 13 of 14 dogs before and 1 of 13 dogs after discontinuation of suspect foods or treats. Seven samples of 5 commercially available products fed to 6 affected dogs were analyzed for thyroxine concentration; results were subjectively compared with findings for 10 other commercial foods and 6 beef muscle or liver samples. Total serum thyroxine concentrations were high (median, 8.8 μg/dL; range, 4.65 to 17.4 μg/dL) in all dogs at initial evaluation; scintigraphy revealed subjectively decreased thyroid gland radionuclide in 13 of 13 dogs examined. At ≥ 4 weeks after feeding of suspect food or treats was discontinued, total thyroxine concentrations were within the reference range for all dogs and signs associated with thyrotoxicosis, if present, had resolved. Analysis of tested food or treat samples revealed a median thyroxine concentration for suspect products of 1.52 μg of thyroxine/g, whereas that of unrelated commercial foods was 0.38 μg of thyroxine/g. Results indicated that thyrotoxicosis can occur secondary to consumption of meat-based products presumably contaminated by thyroid tissue, and can be reversed by identification and elimination of suspect products from the diet.

Dietary hyperthyroidism in dogs.

PubMed

Köhler, B; Stengel, C; Neiger, R

2012-03-01

Evaluation of dogs with elevated plasma thyroxine concentration fed raw food before and after changing the diet. Between 2006 and 2011 all dogs presented with an elevated plasma thyroxine concentration and a dietary history of feeding raw food were included. Thyroxine (reference interval: 19·3 to 51·5 nmol/L) and in many cases also thyroid-stimulating hormone concentrations (reference interval: <0·30 ng/mL) were measured initially and after changing the diet. Twelve dogs were presented with a median age of five years. The median plasma thyroxine concentration was 156·1 (range of 79·7 to 391·9) nmol/L; in six dogs, thyroid-stimulating hormone concentration was measured and was <0·03 ng/mL in five dogs and 0·05 ng/mL in one dog. Six dogs showed clinical signs such as weight loss, aggressiveness, tachycardia, panting and restlessness while six dogs had no clinical signs. After changing the diet eight dogs were examined: thyroxine concentration normalised in all dogs and clinical signs resolved. Dietary hyperthyroidism can be seen in dogs on a raw meat diet or fed fresh or dried gullets. Increased plasma thyroxine concentration in a dog, either with or without signs of hyperthyroidism, should prompt the veterinarian to obtain a thorough dietary history. © 2012 British Small Animal Veterinary Association.

Stripes instability of an oscillating non-Brownian iso-dense suspension of spheres

NASA Astrophysics Data System (ADS)

Roht, Y. L.; Ippolito, I.; Hulin, J. P.; Salin, D.; Gauthier, G.

2018-03-01

We analyze experimentally the behavior of a non-Brownian, iso-dense suspension of spheres submitted to periodic square wave oscillations of the flow in a Hele-Shaw cell of gap H. We do observe an instability of the initially homogeneous concentration in the form of concentration variation stripes transverse to the flow. The wavelength of these regular spatial structures scales roughly as the gap of the cell and is independent of the particle concentration and of the period of oscillation. This instability requires large enough particle volume fractions φ≥ 0.25 and a gap large enough compared to the sphere diameter (H/d ≥ 8) . Mapping the domain of the existence of this instability in the space of the control parameters shows that it occurs only in a limited range of amplitudes of the fluid displacement. The analysis of the concentration distribution across the gap supports a scenario of particle migration towards the wall followed by an instability due to a particle concentration gradient with a larger concentration at the walls. In order to account for the main features of this stripes instability, we use the theory of longitudinal instability due to normal stresses difference and recent observations of a dependence of the first normal stresses difference on the particle concentration.

Using Community-Based Participatory Research to Explore Backyard Gardening Practices and Soil Lead Concentrations in Urban Neighborhoods.

PubMed

Johnson, Sheri; Cardona, Dalila; Davis, Jeremy; Gramling, Benjamin; Hamilton, Chelsea; Hoffmann, Ray; Ruis, Sabrina; Soldat, Doug; Ventura, Steve; Yan, Ke

2016-01-01

Lead exposure is a serious health threat for children. Soil is an important exposure pathway, primarily through ingestion and inhalation. Urban agriculture is increasing. Potential environmental health risks associated with residential gardening may not be well known to community residents. A community-based participatory research (CBPR) approach was implemented to explore the relationship between urban residential vegetable gardening and lead exposure in children. The primary objectives were to characterize local backyard vegetable gardening practices, measure residential and commercial soil lead concentrations and spatial distributions, and identify priorities for individual and collective action. Participants were recruited in two stages. In phase 1, adult gardeners participated in structured interviews. In phase 2, a multistage representative sampling approach was implemented to recruit adult gardeners for interviews and soil testing. Twenty adults participated in gardening practice interviews. Adults perceive many benefits from backyard gardening and initially expressed few concerns about lead exposure risk. Results indicate that children are actively involved in backyard gardening. Total soil lead concentrations from 17 residential properties ranged from 7 to 3,234 mg kg-1(median, 187; mean, 432). Commercial soils had lead concentrations that ranged from 6 to 13 mg kg(-1) (median, 6.5; mean, 7.6). Nonparametric Mann-Whitney comparisons indicated a significant difference in lead concentration between commercial soil and residential soil (p<0.0001). Advocacy for resources needed to eliminate dangerous levels of lead from the environment, especially in communities where divestment has occurred, is enhanced through CBPR. Increasing access to soil testing is an important action step.

Estimations of the lethal and exposure doses for representative methanol symptoms in humans.

PubMed

Moon, Chan-Seok

2017-01-01

The aim of this review was to estimate the lethal and exposure doses of a representative symptom (blindness) of methanol exposure in humans by reviewing data from previous articles. Available articles published from 1970 to 2016 that investigated the dose-response relationship for methanol exposure (i.e., the exposure concentration and the biological markers/clinical symptoms) were evaluated; the MEDLINE and RISS (Korean search engine) databases were searched. The available data from these articles were carefully selected to estimate the range and median of a lethal human dose. The regression equation and correlation coefficient (between the exposure level and urinary methanol concentration as a biological exposure marker) were assumed from the previous data. The lethal human dose of pure methanol was estimated at 15.8-474 g/person as a range and as 56.2 g/person as the median. The dose-response relationship between methanol vapor in ambient air and urinary methanol concentrations was thought to be correlated. An oral intake of 3.16-11.85 g/person of pure methanol could cause blindness. The lethal dose from respiratory intake was reported to be 4000-13,000 mg/l. The initial concentration of optic neuritis and blindness were shown to be 228.5 and 1103 mg/l, respectively, for a 12-h exposure. The concentration of biological exposure indices and clinical symptoms for methanol exposure might have a dose-response relationship according to previous articles. Even a low dose of pure methanol through oral or respiratory exposure might be lethal or result in blindness as a clinical symptom.

Effect of immobilized biosorbents on the heavy metals (Cu2+) biosorption with variations of temperature and initial concentration of waste

NASA Astrophysics Data System (ADS)

Siwi, W. P.; Rinanti, A.; Silalahi, M. D. S.; Hadisoebroto, R.; Fachrul, M. F.

2018-01-01

The aims of research is to studying the efficiency of copper removal by combining immobilized microalgae with optimizations of temperature and initial Copper concentration. The research was conducted in batch culture with temperature variations of 25°C, 30°C, and 35°C, as well as initial Cu2+ concentrations (mg/l) of 3, 5, 10, 15 and 20 using monoculture of S. cerevisiae, Chlorella sp., and mixed culture of them both as immobilized biosorbents. The optimum adsorption of 83.4% obtained in temperature of 30°C with an initial waste concentration of 17.62 mg/l, initial biomass concentration of 200 mg, pH of 4, and 120 minutes detention time by the immobilized mixed culture biosorbent. The cell morphology examined using Scanning Electron Microscope (SEM) has proved that the biosorbent surface was damaged after being in contact with copper (waste), implying that heavy metals (molecules) attach to different functional cell surfaces and change the biosorbent surface. The adsorption process of this research follows Langmuir Isotherm with the R2 value close to 1. The immobilized mixed culture biosorbent is capable of optimally removing copper at temperature of 30°C and initial Cu2+ concentration of 17.62 mg/l.

Can we reduce the number of fish in the OECD acute toxicity test?

PubMed

Rufli, Hans; Springer, Timothy A

2011-04-01

OECD (Organisation for Economic Co-operation and Development) Guideline 203, Fish Acute Toxicity Test, states that the test should be performed using at least five concentrations in a geometric series with a separation factor not exceeding 2.2, with at least seven fish per concentration. However, the efficiency of this design can be questioned, because it often results in only one concentration that causes partial mortality (mortality >0% and <100%). We performed Monte Carlo computer simulations to assess whether more efficient designs could allow reductions in fish use. Simulations indicated that testing with six fish per concentration could yield 50% lethal concentration (LC50) estimates of quality similar to those obtained using seven fish. Experts attending a workshop organized to consider this finding and to identify the best methods for reducing fish use concluded that significant reductions could best be achieved by modifying the test paradigm. They suggested initiating testing using a 96-h fish embryo test instead of juvenile fish to cover the range from the upper threshold concentration (the lowest 50% effective concentration [EC50] in existing algae and daphnia studies) to the highest concentration with no mortality. This would be followed by a confirmatory limit test with juvenile fish at the highest concentration with no mortality or by a full test with juvenile fish, if a point estimate of the LC50 is required. Copyright © 2011 SETAC.

Evaluation of various glyphosate concentrations on DNA damage in human Raji cells and its impact on cytotoxicity.

PubMed

Townsend, Michelle; Peck, Connor; Meng, Wei; Heaton, Matthew; Robison, Richard; O'Neill, Kim

2017-04-01

Glyphosate is a highly used active compound in agriculturally based pesticides. The literature regarding the toxicity of glyphosate to human cells has been highly inconsistent. We studied the resulting DNA damage and cytotoxicity of various glyphosate concentrations on human cells to evaluate DNA damaging potential. Utilizing human Raji cells, DNA damage was quantified using the comet assay, while cytotoxicity was further analyzed using MTT viability assays. Several glyphosate concentrations were assessed, ranging from 15 mM to 0.1 μM. We found that glyphosate treatment is lethal to Raji cells at concentrations above 10 mM, yet has no cytotoxic effects at concentrations at or below 100 μM. Treatment concentrations of 1 mM and 5 mM induce statistically significant DNA damage to Raji cells following 30-60 min of treatment, however, cells show a slow recovery from initial damage and cell viability is unaffected after 2 h. At these same concentrations, cells treated with additional compound did not recover and maintained high levels of DNA damage. While the cytotoxicity of glyphosate appears to be minimal for physiologically relevant concentrations, the compound has a definitive cytotoxic nature in human cells at high concentrations. Our data also suggests a mammalian metabolic pathway for the degradation of glyphosate may be present. Copyright © 2017 Elsevier Inc. All rights reserved.

Gd-DTPA Adsorption on Chitosan/Magnetite Nanocomposites

NASA Astrophysics Data System (ADS)

Pylypchuk, Ie. V.; Kołodyńska, D.; Kozioł, M.; Gorbyk, P. P.

2016-03-01

The synthesis of the chitosan/magnetite nanocomposites is presented. Composites were prepared by co-precipitation of iron(II) and iron(III) salts by aqueous ammonia in the 0.1 % chitosan solution. It was shown that magnetite synthesis in the chitosan medium does not affect the magnetite crystal structure. The thermal analysis data showed 4.6 % of mass concentration of chitosan in the hybrid chitosan/magnetite composite. In the concentration range of initial Gd-DTPA solution up to 0.4 mmol/L, addition of chitosan to magnetite increases the adsorption capacity and affinity to Gd-DTPA complex. The Langmuir and Freundlich adsorption models were applied to describe adsorption processes. Nanocomposites were characterized by scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and specific surface area determination (ASAP) methods.

Evaluation of the source area of rooftop scalar measurements in London, UK using wind tunnel and modelling approaches.

NASA Astrophysics Data System (ADS)

Brocklehurst, Aidan; Boon, Alex; Barlow, Janet; Hayden, Paul; Robins, Alan

2014-05-01

The source area of an instrument is an estimate of the area of ground over which the measurement is generated. Quantification of the source area of a measurement site provides crucial context for analysis and interpretation of the data. A range of computational models exists to calculate the source area of an instrument, but these are usually based on assumptions which do not hold for instruments positioned very close to the surface, particularly those surrounded by heterogeneous terrain i.e. urban areas. Although positioning instrumentation at higher elevation (i.e. on masts) is ideal in urban areas, this can be costly in terms of installation and maintenance costs and logistically difficult to position instruments in the ideal geographical location. Therefore, in many studies, experimentalists turn to rooftops to position instrumentation. Experimental validations of source area models for these situations are very limited. In this study, a controlled tracer gas experiment was conducted in a wind tunnel based on a 1:200 scale model of a measurement site used in previous experimental work in central London. The detector was set at the location of the rooftop site as the tracer was released at a range of locations within the surrounding streets and rooftops. Concentration measurements are presented for a range of wind angles, with the spread of concentration measurements indicative of the source area distribution. Clear evidence of wind channeling by streets is seen with the shape of the source area strongly influenced by buildings upwind of the measurement point. The results of the wind tunnel study are compared to scalar concentration source areas generated by modelling approaches based on meteorological data from the central London experimental site and used in the interpretation of continuous carbon dioxide (CO2) concentration data. Initial conclusions will be drawn as to how to apply scalar concentration source area models to rooftop measurement sites and suggestions for their improvement to incorporate effects such as channeling.

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

Mainali, M; Ngwa, W; Cifter, G

Purpose: The purpose of this research is to investigate the feasibility of using targeted cerium oxide nanoparticles (CONP) during APBI to protect healthy cells. Methods: In one approach, CONP are assumed to be incorporated in a micrometer-thick polymer film on the surface of routinely used mammosite balloon applicators for sustained in-situ release of the CONP. In case two, CONPs are administered directly into the lumpectomy cavity. The concentration of H{sub 2}O{sub 2} produced by ionizing radiation was estimated from previously published work using short range linear extrapolation. The assessment of CONPs concentration required to absorb corresponding H{sub 2}O{sub 2} tomore » protect healthy tissue was calculated. Fick’s Second law of diffusion was employed to determine the initial concentration of CONP needed to achieve the minimum concentration for radioprotection at distance 1 cm and 2 cm from the lumpectomy cavity during APBI. The study was carried out for different nanoparticle sizes. Results: The initial concentration of CONPs required to get desired radioprotection concentration at 1 cm and 2 cm after 7 days was found to be 0.4089 mg per Kg and 59.7605 g per Kg respectively for 2 nm size nanoparticles. Using concentrations of 5 mg per kg of CONP that have been shown to be used to confer radioprotection (for about 7.97 Gy) in experiments it was observed that 4.5631, 8.5286, 10.9247, 22.0408, 43.6796 and 65.5618 number of days are required to achieve radioprotection at 1 cm for CONP of sizes 2 nm, 3.8 nm, 5 nm, 10 nm, 20 nm, 30 nm, respectively. Conclusion: Our preliminary results show that smaller size (2 nm and 3.8 nm) CONP would be suitable as radio protectant during APBI because they took a reasonable number of days, i.e. less than 10 days to reach tissues of 1 cm or 2 cm thickness.« less

Biohydrogen production and wastewater treatment from organic wastewater by anaerobic fermentation with UASB

NASA Astrophysics Data System (ADS)

Wang, Lu; Li, Yong-feng; Wang, Yi-xuan; Yang, Chuan-ping

2010-11-01

In order to discuss the ability of H2-production and wastewater treatment, an up-flow anaerobic sludge bed (UASB) using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the biomass of inoculants was 22.5 g SSṡL-1 and the influent concentration, hydraulic retention time (HRT) and initial pH were within the ranges of 4000˜6000 mg CODṡL-1, 8 h and 5-5.5, respectively, and the biohydrogen producing reactor could work effectively. The maximum hydrogen production rate is 5.98 Lṡd-1. Simultaneously, the concentration of ethanol and acetic acid is around 80% of the aqueous terminal production in the system, which presents the typical ethanol type fermentation. pH is at the range of 4˜4.5 during the whole performing process, however, the removal rate of COD is just about 20%. Therefore, it's still needs further research to successfully achieve the biohydrogen production and wastewater treatment, simultaneously.

Analysis of polar and non-polar VOCs from ambient and source matrices: Development of a new canister autosampler which meets TO-15 QA/QC criteria

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

Burnett, M.L.W.; Neal, D.; Uchtman, R.

1997-12-31

Approximately 108 of the Hazardous Air Pollutants (HAPs) specified in the 1990 Clean Air Act Amendments are classified as volatile organic compounds (VOCs). Of the 108 VOCs, nearly 35% are oxygenated or polar compounds. While more than one sample introduction technique exists for the analysis of these air toxics, SUMMA{reg_sign} canister sampling is suitable for the most complete range of analytes. A broad concentration range of polar and non-polar species can be analyzed from canisters. A new canister autosampler, the Tekmar AUTOCan{trademark} Elite autosampler, has been developed which incorporates the autosampler and concentrator into a single unit. Analysis of polarmore » and non-polar VOCs has been performed. This paper demonstrates adherence to the technical acceptance objectives outlined in the TO-15 methodology including initial calibration, daily calibration, blank analysis, method detection limits and laboratory control samples. The analytical system consists of a Tekmar AUTOCan{trademark} Elite autosampler interfaced to a Hewlett Packard{reg_sign} 5890/5972 MSD.« less

The Influence of the Severity of Chronic Virus-Related Liver Disease on Propofol Requirements during Propofol-Remifentanil Anesthesia

PubMed Central

Wu, Jian; Huang, Su-Qin; Chen, Qing-Lian

2013-01-01

Purpose The purpose of this study was to investigate the influence of chronic virus-related liver disease severity on propofol requirements. Materials and Methods In this study, 48 male patients with chronic hepatitis B infection were divided into three groups according to Child-Turcotte-Pugh classification of liver function (groups A, B, and C with mild, moderate and severe liver disease, respectively). After intubation, propofol concentration was adjusted by ±0.3 µg/mL increments to maintain bispectral index in the range of 40-60. Target propofol concentrations at anesthesia initiation, pre-intubation and pre-incision were recorded. Results The initial concentration used in group C was significantly lower than that used in group A or B (p<0.05), whereas no difference was observed between groups A and B. At pre-intubation, the actual required concentration of propofol increased significantly (3.2 µg/mL) in group A (p<0.05), which lead to significant differences between the groups (p<0.05). At pre-incision, the requirements for propofol decreased significantly in both groups A and B (3.0 µg/mL and 2.7 µg/mL, respectively) compared with those at pre-intubation (p<0.05), and were significantly different for all three groups (p<0.05), with group C demonstrating the lowest requirement (2.2 µg/mL). The required concentrations of propofol at pre-incision were similar to those at induction. Conclusion In this study, propofol requirements administered by target-controlled infusion to maintain similar depths of hypnosis were shown to depend on the severity of chronic virus-related liver dysfunction. In other words, patients with the most severe liver dysfunction required the least amount of propofol. PMID:23225825

Changes of the serum antibiotic levels during open heart surgery (ceftazidim, ciprofloxacin, clindamycin).

PubMed

Lonský, V; Dominik, J; Mand'ák, J; Pozlerová, E; Hejzlar, M; Lonská, V; Marsíková, M; Kubícek, J; Snítilová, M

2000-01-01

Wound, mediastinal and intracardiac infections are still very serious complications of open-heart surgery. The incidence of it is still in the range of 0.4%-5%. The aims of our study were to assess the adequacy of regimen using ceftazidim (CTZ), ciprofloxacin (CPF) and clindamycin (CLIN) as prophylactic antibiotics and to verify whether cardiopulmonary bypass (CPB) can modify the time of antibiotic serum concentrations. That is why the serum levels of them were measured during open heart procedures. The prospective study comprised 75 consequent coronary patients randomized in to three groups receiving 1 g of CTZ or 400 mg of CPF or 900 mg of CLIN i.v. with anesthesia induction. Routine coronary surgery with left internal mammary artery harvesting, moderate body hypothermic (30 degrees C) CPB with crystaloid cardioplegia was performed. Serum antibiotic levels were determined before application, with skin incision, prior CPB induction, after cardioplegia infusion, every 20 minutes of CPB, prior end of CPB, in time of chest closure. Conventional cylinder-plate microbiological assay was used for antibiotic level measurement. All serum antibiotic concentrations showed a sharp decrease immediately after starting CPB and lasted until CPB ended. After initiating of CPB after cardioplegia administration serum concentrations of CTZ (105 min after initial dose) decreased by, on average 55%, CPF (97 min) by 42% and CLIN (116 min) by 78%. CPB can modify the time course of antibiotic serum concentrations. The serum levels of CTZ at the end of the longest procedures were found to be below the MICs for some of the suspected pathogens. We recommend to use higher antibiotic doses for prophylaxis and to administer the second dose with protamin sulphate to obtain maximum concentration in newly formed blood clots.

Effects of pH and Temperature on the Stability of Fumonisins in Maize Products.

PubMed

Bryła, Marcin; Waśkiewicz, Agnieszka; Szymczyk, Krystyna; Jędrzejczak, Renata

2017-03-01

This paper is a study of the stability of fumonisins in dough based on maize flour prepared in a phosphate buffer with a pH of 3.5, 5.5 or 7.5 and baked at a temperature within the range of 100-250 °C. Buffers with various pH values were tested, since it is well-known that pH may significantly influence interactions of fumonisins with other substances. A standard analytical procedure was used to determine the concentration of free fumonisins. Hydrolysis in an alkaline medium was then applied to reveal the hidden forms, while the total fumonisins concentations was determined in another measurement. The total concentration of fumonisins was statistically higher in pH = 3.5 and pH = 5.5 than the concentration of free fumonisins; no similar difference was found at pH = 7.5. The applied phosphate buffer pH 7.5 may enhance solubility of fumonisins, which would increase extraction efficiency of free analytes, thereby decreasing the difference between concentrations of total and free fumonisins. Hydrolysed B₁ fumonisin (HFB₁) and partially hydrolysed B₁ fumonisin (isomers a and b: PHFB 1a and PHFB 1b , respectively) were the main investigated substances. For baking temperatures below 220 °C, fumonisins were slightly more stable for pH = 5.5 than for pH = 3.5 and pH = 7.5. In both of these latter cases, the concentration of partially hydrolysed fumonisins grew initially (up to 200 °C) with an increase in the baking temperature, and then dropped. Similar behaviour was observed for free HFB₁, which may suggest the following fumonisin degradation mechanism: initially, the tricarballylic acid (TCA) groups are removed from the molecules, and next, the HFB₁ molecules disintegrate.

Effects of pH and Temperature on the Stability of Fumonisins in Maize Products

PubMed Central

Bryła, Marcin; Waśkiewicz, Agnieszka; Szymczyk, Krystyna; Jędrzejczak, Renata

2017-01-01

This paper is a study of the stability of fumonisins in dough based on maize flour prepared in a phosphate buffer with a pH of 3.5, 5.5 or 7.5 and baked at a temperature within the range of 100–250 °C. Buffers with various pH values were tested, since it is well-known that pH may significantly influence interactions of fumonisins with other substances. A standard analytical procedure was used to determine the concentration of free fumonisins. Hydrolysis in an alkaline medium was then applied to reveal the hidden forms, while the total fumonisins concentations was determined in another measurement. The total concentration of fumonisins was statistically higher in pH = 3.5 and pH = 5.5 than the concentration of free fumonisins; no similar difference was found at pH = 7.5. The applied phosphate buffer pH 7.5 may enhance solubility of fumonisins, which would increase extraction efficiency of free analytes, thereby decreasing the difference between concentrations of total and free fumonisins. Hydrolysed B1 fumonisin (HFB1) and partially hydrolysed B1 fumonisin (isomers a and b: PHFB1a and PHFB1b, respectively) were the main investigated substances. For baking temperatures below 220 °C, fumonisins were slightly more stable for pH = 5.5 than for pH = 3.5 and pH = 7.5. In both of these latter cases, the concentration of partially hydrolysed fumonisins grew initially (up to 200 °C) with an increase in the baking temperature, and then dropped. Similar behaviour was observed for free HFB1, which may suggest the following fumonisin degradation mechanism: initially, the tricarballylic acid (TCA) groups are removed from the molecules, and next, the HFB1 molecules disintegrate. PMID:28257053

Growth-incompetent monomers of human calcitonin lead to a noncanonical direct relationship between peptide concentration and aggregation lag time.

PubMed

Kamgar-Parsi, Kian; Hong, Liu; Naito, Akira; Brooks, Charles L; Ramamoorthy, Ayyalusamy

2017-09-08

The role of the peptide hormone calcitonin in skeletal protection has led to its use as a therapeutic for osteoporosis. However, calcitonin aggregation into amyloid fibrils limits its therapeutic efficacy, necessitating a modification of calcitonin's aggregation kinetics. Here, we report a direct relationship between human calcitonin (hCT) concentration and aggregation lag time. This kinetic trend was contrary to the conventional understanding of amyloid aggregation and persisted over a range of aggregation conditions, as confirmed by thioflavin-T kinetics assays, CD spectroscopy, and transmission EM. Dynamic light scattering, 1 H NMR experiments, and seeded thioflavin-T assay results indicated that differences in initial peptide species contribute to this trend more than variations in the primary nucleus formation rate. On the basis of kinetics modeling results, we propose a mechanism whereby a structural conversion of hCT monomers is needed before incorporation into the fibril. Our kinetic mechanism recapitulates the experimentally observed relationship between peptide concentration and lag time and represents a novel mechanism in amyloid aggregation. Interestingly, hCT at low pH and salmon calcitonin (sCT) exhibited the canonical inverse relationship between concentration and lag time. Comparative studies of hCT and sCT with molecular dynamics simulations and CD indicated an increased α-helical structure in sCT and low-pH hCT monomers compared with neutral-pH hCT, suggesting that α-helical monomers represent a growth-competent species, whereas unstructured random coil monomers represent a growth-incompetent species. Our finding that initial monomer concentration is positively correlated with lag time in hCT aggregation could help inform future efforts for improving therapeutic applications of CT. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Comparison of salting-out and sugaring-out liquid-liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content.

PubMed

Tu, Xijuan; Sun, Fanyi; Wu, Siyuan; Liu, Weiyi; Gao, Zhaosheng; Huang, Shaokang; Chen, Wenbin

2018-01-15

Homogeneous liquid-liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid-liquid extraction (SALLE) and sugaring-out assisted liquid-liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO 4 in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO 4 SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO 4 showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly. Copyright © 2017 Elsevier B.V. All rights reserved.

Bio sorption of strontium from aqueous solution by New Strain Bacillus sp. GTG-83

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

Tajer Mohammad Ghazvini, P.; Ghorbanzadeh Mashkani, S.; Ghafourian, H.

Attempt was made to isolate bacterial strains capable of removing Sr biologically. In this study we collected ten different water samples from naturally radioactive spring Neydasht in Iran and bacterial strains samples isolated. Initial screening of a total of 50 bacterial isolates resulted in selection of one strain. The strain showed maximum adsorption capacity with 55 mg Sr/g dry wt. It was tentatively identified as Bacillus sp. according to morphological and biochemical properties and called strain GTG-83. Studies indicated that Bacillus sp. GTG-83 was able to grow aerobically in the presence of 50 mM SrCl{sub 2} but showed severe growthmore » inhibition at levels above that concentration. The bio-sorption capacity of Bacillus sp. GTG-83 strongly depends on solution pH, and the maximum Sr sorption capacity of Bacillus sp. GTG-83 were obtained at pH 10 independent of the absence or the presence of increasing concentrations of salt (MgCl{sub 2}). Sr-salt bio-sorption studies were also performed at this pH values. Equilibrium uptakes of Sr increased with increasing Sr concentrations up to 250 mg/l for Bacillus sp. GTG-83. Maximum bio-sorption of Sr was obtained at temperatures in the range of 30-35 deg. C. Bacillus sp. GTG-83 bio-sorbed 97 mg Sr/g dry wt at 100 mg/l initial Sr concentration without salt medium (MgCl{sub 2}). When salt concentration (MgCl{sub 2}) increased to 15% (w/v), these values dropped to 23.6 mg Sr/g dry wt at the same conditions. Uptake of Sr within 5 min of incubation was relatively rapid and the absorption continued slowly thereafter. (authors)« less

Different removal behaviours of multiple trace antibiotics in municipal wastewater chlorination.

PubMed

Li, Bing; Zhang, Tong

2013-06-01

The chlorination behaviours of 12 antibiotics belonging to six classes at environmentally relevant concentrations were systematically examined under typical conditions relevant to municipal wastewater chlorination. Cefotaxime, cefalexin, ampicillin and tetracycline were completely removed under all three initial free chlorine dosages (5 mg/L, 10 mg/L, and 15 mg/L). The removal efficiencies of sulphamethoxazole, sulphadiazine, roxithromycin, anhydro-erythromycin, ofloxacin, and trimethoprim were closely correlated to the residual free chlorine concentration, and no further significant mass removal was observed after the residual free chlorine concentration decreased to less than ≈ 0.75 mg/L. Ammonia plays a critical role during chlorination because of its competition with antibiotics for free chlorine to form combined chlorine, which reacts slowly with these antibiotics. Except for norfloxacin and ciprofloxacin, the removal behaviours of the 10 other target antibiotics under ammonia nitrogen concentrations ranging from 2 to 15 mg/L were characterised by a rapid initial removal rate upon contact with free chlorine during the first 5 s-1 min (depending on the specific antibiotic and ammonia nitrogen concentration) and then a much slower removal rate. Free chlorine was responsible for the reaction with antibiotics during the rapid stage (first 5 s-1 min), whereas combined chlorine reacted with antibiotics in the subsequent slow stage. Combined chlorine can remove norfloxacin and ciprofloxacin at a relatively faster rate. The presence of suspended solids at 30 mg/L slightly decreased the antibiotic removal rate. The kinetic rate constants decreased by 2.1-13.9%, while the half-lives increased by 2.0-15.0% compared to those of a 0 mg/L suspended solid for the target antibiotics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Atomic Resonance Radiation Energetics Investigation as a Diagnostic Method for Non-Equilibrium Hypervelocity Flows

NASA Technical Reports Server (NTRS)

Meyer, Scott A.; Bershader, Daniel; Sharma, Surendra P.; Deiwert, George S.

1996-01-01

Absorption measurements with a tunable vacuum ultraviolet light source have been proposed as a concentration diagnostic for atomic oxygen, and the viability of this technique is assessed in light of recent measurements. The instrumentation, as well as initial calibration measurements, have been reported previously. We report here additional calibration measurements performed to study the resonance broadening line shape for atomic oxygen. The application of this diagnostic is evaluated by considering the range of suitable test conditions and requirements, and by identifying issues that remain to be addressed.

Detailed mechanism of benzene oxidation

NASA Technical Reports Server (NTRS)

Bittker, David A.

1987-01-01

A detailed quantitative mechanism for the oxidation of benzene in both argon and nitrogen diluted systems is presented. Computed ignition delay time for argon diluted mixtures are in satisfactory agreement with experimental results for a wide range of initial conditions. An experimental temperature versus time profile for a nitrogen diluted oxidation was accurately matched and several concentration profiles were matched qualitatively. Application of sensitivity analysis has given approximate rate constant expressions for the two dominant heat release reactions, the oxidation of C6H5 and C5H5 radicals by molecular oxygen.

Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening.

PubMed

Böttcher, Christine; Burbidge, Crista A; Boss, Paul K; Davies, Christopher

2013-12-23

Fruit development is controlled by plant hormones, but the role of hormone interactions during fruit ripening is poorly understood. Interactions between ethylene and the auxin indole-3-acetic acid (IAA) are likely to be crucial during the ripening process, since both hormones have been shown to be implicated in the control of ripening in a range of different fruit species. Grapevine (Vitis vinifera L.) homologues of the TRYPTOPHAN AMINOTRANSFERASE RELATED (TAR) and YUCCA families, functioning in the only characterized pathway of auxin biosynthesis, were identified and the expression of several TAR genes was shown to be induced by the pre-ripening application of the ethylene-releasing compound Ethrel. The induction of TAR expression was accompanied by increased IAA and IAA-Asp concentrations, indicative of an upregulation of auxin biosynthesis and conjugation. Exposure of ex planta, pre-ripening berries to the ethylene biosynthesis inhibitor aminoethoxyvinylglycine resulted in decreased IAA and IAA-Asp concentrations. The delayed initiation of ripening observed in Ethrel-treated berries might therefore represent an indirect ethylene effect mediated by increased auxin concentrations. During berry development, the expression of three TAR genes and one YUCCA gene was upregulated at the time of ripening initiation and/or during ripening. This increase in auxin biosynthesis gene expression was preceded by high expression levels of the ethylene biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase and 1-aminocyclopropane-1-carboxylate oxidase. In grape berries, members of both gene families involved in the two-step pathway of auxin biosynthesis are expressed, suggesting that IAA is produced through the combined action of TAR and YUCCA proteins in developing berries. The induction of TAR expression by Ethrel applications and the developmental expression patterns of auxin and ethylene biosynthesis genes indicate that elevated concentrations of ethylene prior to the initiation of ripening might lead to an increased production of IAA, suggesting a complex involvement of this auxin and its conjugates in grape berry ripening.

Peracetic acid disinfection: a feasible alternative to wastewater chlorination.

PubMed

Rossi, S; Antonelli, M; Mezzanotte, V; Nurizzo, C

2007-04-01

The paper summarizes the results of a bench-scale study to evaluate the feasibility of using peracetic acid (PAA) as a substitute for sodium hypochlorite both for discharge into surface water and for agricultural reuse. Trials were carried out with increasing doses (1, 2, 3, 5, 10, and 15 mg/L) and contact times (6, 12, 18, 36, 42, and 54 minutes) to study disinfectant decay and bacterial removal and regrowth, using fecal coliform and Escherichia coli (E. coli) as process efficiency indicators. Peracetic acid decay kinetics was evaluated in tap water and wastewater; in both cases, PAA decays according to first-order kinetics with respect to time, and a correlation was found between PAA oxidative initial consumption and wastewater characteristics. The PAA disinfection efficiency was correlated with operating parameters (active concentration and contact time), testing different kinetic models. Two data groups displaying a different behavior on the basis of initial active concentration ranges (1 to 2 mg/L and 5 to 15 mg/L, respectively) can be outlined. Both groups had a "tailing-off" inactivation curve with respect to time, but the second one showed a greater inactivation rate. Moreover, the effect of contact time was greater at the lower doses. Hom's model, used separately for the two data groups, was found to best fit experimental data, and the disinfectant active concentration appears to be the main factor affecting log-survival ratios. Moreover, the S-model better explains the initial resistance of E. coli, especially at low active concentrations (< 2 mg/L) and short contact times (< 12 minutes). Microbial counts, performed by both traditional methods and flow cytometry, immediately and 5 hours after sample collection (both with or without residual PAA inactivation), showed that no appreciable regrowth took place after 5 hours, neither for coliform group bacteria, nor for total heterotrophic bacteria.

Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening

PubMed Central

2013-01-01

Background Fruit development is controlled by plant hormones, but the role of hormone interactions during fruit ripening is poorly understood. Interactions between ethylene and the auxin indole-3-acetic acid (IAA) are likely to be crucial during the ripening process, since both hormones have been shown to be implicated in the control of ripening in a range of different fruit species. Results Grapevine (Vitis vinifera L.) homologues of the TRYPTOPHAN AMINOTRANSFERASE RELATED (TAR) and YUCCA families, functioning in the only characterized pathway of auxin biosynthesis, were identified and the expression of several TAR genes was shown to be induced by the pre-ripening application of the ethylene-releasing compound Ethrel. The induction of TAR expression was accompanied by increased IAA and IAA-Asp concentrations, indicative of an upregulation of auxin biosynthesis and conjugation. Exposure of ex planta, pre-ripening berries to the ethylene biosynthesis inhibitor aminoethoxyvinylglycine resulted in decreased IAA and IAA-Asp concentrations. The delayed initiation of ripening observed in Ethrel-treated berries might therefore represent an indirect ethylene effect mediated by increased auxin concentrations. During berry development, the expression of three TAR genes and one YUCCA gene was upregulated at the time of ripening initiation and/or during ripening. This increase in auxin biosynthesis gene expression was preceded by high expression levels of the ethylene biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase and 1-aminocyclopropane-1-carboxylate oxidase. Conclusions In grape berries, members of both gene families involved in the two-step pathway of auxin biosynthesis are expressed, suggesting that IAA is produced through the combined action of TAR and YUCCA proteins in developing berries. The induction of TAR expression by Ethrel applications and the developmental expression patterns of auxin and ethylene biosynthesis genes indicate that elevated concentrations of ethylene prior to the initiation of ripening might lead to an increased production of IAA, suggesting a complex involvement of this auxin and its conjugates in grape berry ripening. PMID:24364881

Effect of initiator concentration to low-density polyethylene production in a tubular reactor

NASA Astrophysics Data System (ADS)

Azmi, A.; Aziz, N.

2016-11-01

Low-density polyethylene (LDPE) is one of the most widely used polymers in the world, which is produced in high-capacity tubular and autoclave reactors. As the LDPE industry turn into more competitive and its market profit margins become tighter, manufacturers have to develop solutions to debottleneck the reactor output while abiding to the stringent product specification. A single polyolefin plant producing ten to forty grades of LDPE with various melt flow index (MFI), therefore understanding the reaction mechanism, the operating conditions as well as the dynamic behavior of tubular reactor is essential before any improvement can take place. In the present work, a steady state mathematical model representing a tubular reactor for the production of LDPE is simulated using MATLAB R2015a®. The model developed is a function of feed inlet, reactor jacket, single initiator injector and outlet stream. Analysis on the effect of initiator concentration (CI) shows sudden declining trend of initiator's concentration which indicates that all of the initiators are exhausted after polymerization reaction and no further reaction occur from this point onwards. Furthermore, the results demonstrate that the concentration of initiator gives significant impact on reactor temperature's profile and monomer conversion rate, since higher initiator concentration promotes greater polymerization rate, and therefore leads to higher monomer conversion throughput.

Equilibrium Gold Nanoclusters Quenched with Biodegradable Polymers

PubMed Central

Murthy, Avinash K.; Stover, Robert J.; Borwankar, Ameya U.; Nie, Golay D.; Gourisankar, Sai; Truskett, Thomas M.; Sokolov, Konstantin V.; Johnston, Keith P.

2013-01-01

Although sub-100 nm nanoclusters of metal nanoparticles are of interest in many fields including biomedical imaging, sensors and catalysis, it has been challenging to control their morphologies and chemical properties. Herein, a new concept is presented to assemble equilibrium Au nanoclusters of controlled size by tuning the colloidal interactions with a polymeric stabilizer, PLA(1k)-b-PEG(10k)-b-PLA(1k). The nanoclusters form upon mixing a dispersion of ~5 nm Au nanospheres with a polymer solution followed by partial solvent evaporation. A weakly adsorbed polymer quenches the equilibrium nanocluster size and provides steric stabilization. Nanocluster size is tuned from ~20 nm to ~40 nm by experimentally varying the final Au nanoparticle concentration and the polymer/Au ratio, along with the charge on the initial Au nanoparticle surface. Upon biodegradation of the quencher, the nanoclusters reversibly and fully dissociate to individual ~5 nm primary particles. Equilibrium cluster size is predicted semi-quantitatively with a free energy model that balances short-ranged depletion and van der Waals attractions with longer-ranged electrostatic repulsion, as a function of the Au and polymer concentrations. The close spacings of the Au nanoparticles in the clusters produce strong NIR extinction over a broad range of wavelengths from 650 to 900 nm, which is of practical interest in biomedical imaging. PMID:23230905

Electro-hydrodynamic generation of monodisperse nanoparticles in the sub-10 nm size range from strongly electrolytic salt solutions: governing parameters of scaling laws

NASA Astrophysics Data System (ADS)

Maißer, Anne; Attoui, Michel B.; Gañán-Calvo, Alfonso M.; Szymanski, Wladyslaw W.

2013-01-01

A charge reduced electro-hydrodynamic atomization (EHDA) device has been used to generate airborne salt clusters in the sub 10 nm size range. The focus of this study on that specific sub-micron range of electrospray droplets with relatively high electrical conductivities and permittivities aims to address the still existing controversy on the scaling laws of electrosprayed droplet diameters. In this study different concentrations of sodium chloride and potassium chloride—both show strong electrolytic behavior—have been electrosprayed from solutions in pure water, or from aqueous ammonium acetate buffer liquids of varying concentrations. The dry residue salt cluster diameter generated by the EHDA process have been measured using a differential mobility analyzer. The initial droplet diameter has been determined indirectly from the measured particle size following the steps of Chen et al. (J Aerosol Sci 26:963-977, 1995). Results have been compared to existing scaling laws valid for direct droplet measurements. They can be interpreted concisely on the basis of a realistic hypothesis on possible electrochemical effects taking place and affecting the droplet and thus nanoparticle formation in EHDA. The hypothesis developed in this work and the comparison with the experimental results are shown and discussed in the manuscript.

Acetaminophen degradation by electro-Fenton and photoelectro-Fenton using a double cathode electrochemical cell.

PubMed

de Luna, Mark Daniel G; Veciana, Mersabel L; Su, Chia-Chi; Lu, Ming-Chun

2012-05-30

Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box-Behnken design was used to determine the effects of initial Fe(2+) and H(2)O(2) concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe(2+) concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

Significance of groundwater flux on contaminant concentration and mass discharge in the nonaqueous phase liquid (NAPL) contaminated zone.

PubMed

Zhu, Jianting; Sun, Dongmin

2016-09-01

Groundwater flowing through residual nonaqueous phase liquid (NAPL) source zone will cause NAPL dissolution and generate large contaminant plume. The use of contaminant mass discharge (CMD) measurements in addition to NAPL aqueous phase concentration to characterize site conditions and assess remediation performance is becoming popular. In this study, we developed new and generic numerical models to investigate the significance of groundwater flux temporal variations on the NAPL source dynamics. The developed models can accommodate any temporal variations of groundwater flux in the source zone. We examined the various features of groundwater flux using a few selected functional forms of linear increase/decrease, gradual smooth increase/decrease, and periodic fluctuations with a general trend. Groundwater flux temporal variations have more pronounced effects on the contaminant mass discharge dynamics than the aqueous concentration. If the groundwater flux initially increases, then the reduction in contaminant mass discharge (CMDR) vs. NAPL mass reduction (MR) relationship is mainly downward concave. If the groundwater flux initially decreases, then CMDR vs. MR relationship is mainly upward convex. If the groundwater flux variations are periodic, the CMDR vs. MR relationship tends to also have periodic variations ranging from upward convex to downward concave. Eventually, however, the CMDR vs. MR relationship approaches 1:1 when majority of the NAPL mass becomes depleted. Copyright © 2016 Elsevier B.V. All rights reserved.

Immunoassay and antibody microarray analysis of the HUPO Plasma Proteome Project reference specimens: Systematic variation between sample types and calibration of mass spectrometry data

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

Haab, Brian B.; Geierstanger, Bernhard H.; Michailidis, George

2005-08-01

Four different immunoassay and antibody microarray methods performed at four different sites were used to measure the levels of a broad range of proteins (N = 323 assays; 39, 88, 168, and 28 assays at the respective sites; 237 unique analytes) in the human serum and plasma reference specimens distributed by the Plasma Proteome Project (PPP) of the HUPO. The methods provided a means to (1) assess the level of systematic variation in protein abundances associated with blood preparation methods (serum, citrate-anticoagulated-plasma, EDTA-anticoagulated-plasma, or heparin-anticoagulated-plasma) and (2) evaluate the dependence on concentration of MS-based protein identifications from data sets usingmore » the HUPO specimens. Some proteins, particularly cytokines, had highly variable concentrations between the different sample preparations, suggesting specific effects of certain anticoagulants on the stability or availability of these proteins. The linkage of antibody-based measurements from 66 different analytes with the combined MS/MS data from 18 different laboratories showed that protein detection and the quality of MS data increased with analyte concentration. The conclusions from these initial analyses are that the optimal blood preparation method is variable between analytes and that the discovery of blood proteins by MS can be extended to concentrations below the ng/mL range under certain circumstances. Continued developments in antibody-based methods will further advance the scientific goals of the PPP.« less

Sub-lethal effects of the neurotoxic pyrethroid insecticide Fastac 50EC on the general motor and locomotor activities of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

PubMed

Tooming, Ene; Merivee, Enno; Must, Anne; Sibul, Ivar; Williams, Ingrid

2014-06-01

Sub-lethal effects of pesticides on behavioural endpoints are poorly studied in carabids (Coleoptera: Carabidae) though changes in behaviour caused by chemical stress may affect populations of these non-targeted beneficial insects. General motor activity and locomotion are inherent in many behavioural patterns, and changes in these activities that result from xenobiotic influence mirror an integrated response of the insect to pesticides. Influence of pyrethroid insecticides over a wide range of sub-lethal doses on the motor activities of carabids still remains unclear. Video tracking of Platynus assimilis showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations ranged from 0.01 to 100 mg L(-1) caused initial short-term (< 2 h) locomotor hyperactivity followed by a long-term (>24 h) locomotor hypo-activity. In addition, significant short- and long-term concentration and time-dependent changes occurred in general motor activity patterns and rates. Conspicuous changes in motor activity of Platynus assimilis beetles treated at alpha-cypermethrin concentrations up to 75,000-fold lower than maximum field recommended concentration (MFRC) suggest that many, basic fitness-related behaviours might be severely injured as well. These changes may negatively affect carabid populations in agro-ecosystems. Long-term hypo-activity could directly contribute to decreased trap captures of carabids frequently observed after insecticide application in the field. © 2013 Society of Chemical Industry.

Design and Analysis of Compact DNA Strand Displacement Circuits for Analog Computation Using Autocatalytic Amplifiers.

PubMed

Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

2018-01-19

A main goal in DNA computing is to build DNA circuits to compute designated functions using a minimal number of DNA strands. Here, we propose a novel architecture to build compact DNA strand displacement circuits to compute a broad scope of functions in an analog fashion. A circuit by this architecture is composed of three autocatalytic amplifiers, and the amplifiers interact to perform computation. We show DNA circuits to compute functions sqrt(x), ln(x) and exp(x) for x in tunable ranges with simulation results. A key innovation in our architecture, inspired by Napier's use of logarithm transforms to compute square roots on a slide rule, is to make use of autocatalytic amplifiers to do logarithmic and exponential transforms in concentration and time. In particular, we convert from the input that is encoded by the initial concentration of the input DNA strand, to time, and then back again to the output encoded by the concentration of the output DNA strand at equilibrium. This combined use of strand-concentration and time encoding of computational values may have impact on other forms of molecular computation.

Screening of novel bacteria for the 2,3-butanediol production.

PubMed

Kallbach, Malee; Horn, Sonja; Kuenz, Anja; Prüße, Ulf

2017-02-01

Biotechnologically produced 2,3-butanediol (2,3-BDO) is a potential starting material for industrial bulk chemicals such as butadiene or methyl ethyl ketone which are currently produced from fossil feedstocks. So far, the highest 2,3-BDO concentrations have been obtained with risk group 2 microorganisms. In this study, three risk group 1 microorganisms are presented that are so far unknown for an efficient production of 2,3-BDO. The strains Bacillus atrophaeus NRS-213, Bacillus mojavensis B-14698, and Bacillus vallismortis B-14891 were evaluated regarding their ability to produce high 2,3-BDO concentrations with a broad range of different carbon sources. A maximum 2,3-BDO concentration of 60.4 g/L was reached with the strain B. vallismortis B-14891 with an initial glucose concentration of 200 g/L within 55 h in a batch cultivation. Besides glucose, B. vallismortis B-14891 converts 14 different substrates that can be obtained from residual biomass sources to 2,3-BDO. Therefore B. vallismortis B-14891 is a promising candidate for the large-scale production of 2,3-BDO with low-cost substrates.

Stability of florfenicol in drinking water.

PubMed

Hayes, John M; Eichman, Jonathan; Katz, Terry; Gilewicz, Rosalia

2003-01-01

Florfenicol, a broad-spectrum antibiotic, is being developed for veterinary application as an oral concentrate intended for dilution with drinking water. When a drug product is dosed via drinking water in a farm setting, a number of variables, including pH, chlorine content, hardness of the water used for dilution, and container material, may affect its stability, leading to a decrease in drug potency. The stability of florfenicol after dilution of Florfenicol Drinking Water Concentrate Oral Solution, 23 mg/mL, with drinking water was studied. A stability-indicating, validated liquid chromatographic method was used to evaluate florfenicol stability at 25 degrees C at 5, 10, and 24 h after dilution. The results indicate that florfenicol is stable under a range of simulated field conditions, including various pipe materials and conditions of hard or soft and chlorinated or nonchlorinated water at low or high pH. Significant degradation (> 10%) was observed only for isolated combinations in galvanized pipes. Analysis indicated that the florfenicol concentration in 8 of the 12 water samples stored in galvanized pipes remained above 90% of the initial concentration (100 mg/L) for 24 h after dilution.

Phosphate removal from aqueous solutions using raw and activated red mud and fly ash.

PubMed

Li, Yanzhong; Liu, Changjun; Luan, Zhaokun; Peng, Xianjia; Zhu, Chunlei; Chen, Zhaoyang; Zhang, Zhongguo; Fan, Jinghua; Jia, Zhiping

2006-09-01

The effect of acidification and heat treatment of raw red mud (RM) and fly ash (FA) on the sorption of phosphate was studied in parallel experiments. The result shows that a higher efficiency of phosphate removal was acquired by the activated samples than by the raw ones. The sample prepared by using the RM stirred with 0.25 M HCl for 2h (RM0.25), as well as another sample prepared by heating the RM at 700 degrees C for 2h (RM700), registered the maximum removal of phosphate (99% removal of phosphate). This occurred when they were used in the phosphate sorption studies conducted at pH 7.0 and 25 degrees C with the initial PO(4)(3-) concentration of 155 mg P/l. The FA samples treated in the same way described above can achieve 7.0 and 8.2 mg P/l phosphate removal for FA0.25 and FA700 respectively, corresponding to 45.2% and 52.9% removal. The activated materials performed higher phosphate removal over broader pH range compared with the raw ones. The influences of various factors, such as initial pH and initial phosphate concentration on the sorption capacity were also studied in batch equilibration technique. Solution pH significantly influenced the sorption. Each sample achieved the maximal removal of phosphate at pH 7.0. The amount of phosphate removal increased with the solute concentration. The Freundlich and Langmuir models were used to simulate the sorption equilibrium. The results indicate that the Langmuir model has a better correlation with the experimental data than the Freundlich model.

Effectiveness of early intensive therapy on β-cell preservation in type 1 diabetes.

PubMed

Buckingham, Bruce; Beck, Roy W; Ruedy, Katrina J; Cheng, Peiyao; Kollman, Craig; Weinzimer, Stuart A; DiMeglio, Linda A; Bremer, Andrew A; Slover, Robert; Tamborlane, William V

2013-12-01

To assess effectiveness of inpatient hybrid closed-loop control (HCLC) followed by outpatient sensor-augmented pump (SAP) therapy initiated within 7 days of diagnosis of type 1 diabetes on the preservation of β-cell function at 1 year. Sixty-eight individuals (mean age 13.3 ± 5.7 years; 35% female, 92% Caucasian) were randomized to HCLC followed by SAP therapy (intensive group; N = 48) or to the usual-care group treated with multiple daily injections or insulin pump therapy (N = 20). Primary outcome was C-peptide concentrations during mixed-meal tolerance tests at 12 months. Intensive-group participants initiated HCLC a median of 6 days after diagnosis for a median duration of 71.3 h, during which median participant mean glucose concentration was 140 mg/dL (interquartile range 134-153 mg/dL). During outpatient SAP, continuous glucose monitor (CGM) use decreased over time, and at 12 months, only 33% of intensive participants averaged sensor use ≥6 days/week. In the usual-care group, insulin pump and CGM use were initiated prior to 12 months by 15 and 5 participants, respectively. Mean HbA1c levels were similar in both groups throughout the study. At 12 months, the geometric mean (95% CI) of C-peptide area under the curve was 0.43 (0.34-0.52) pmol/mL in the intensive group and 0.52 (0.32-0.75) pmol/mL in the usual-care group (P = 0.49). Thirty-seven (79%) intensive and 16 (80%) usual-care participants had a peak C-peptide concentration ≥0.2 pmol/mL (P = 0.30). In new-onset type 1 diabetes, HCLC followed by SAP therapy did not provide benefit in preserving β-cell function compared with current standards of care.

Ice nucleation active bacteria in precipitation are genetically diverse and nucleate ice by employing different mechanisms.

PubMed

Failor, K C; Schmale, D G; Vinatzer, B A; Monteil, C L

2017-12-01

A growing body of circumstantial evidence suggests that ice nucleation active (Ice + ) bacteria contribute to the initiation of precipitation by heterologous freezing of super-cooled water in clouds. However, little is known about the concentration of Ice + bacteria in precipitation, their genetic and phenotypic diversity, and their relationship to air mass trajectories and precipitation chemistry. In this study, 23 precipitation events were collected over 15 months in Virginia, USA. Air mass trajectories and water chemistry were determined and 33 134 isolates were screened for ice nucleation activity (INA) at -8 °C. Of 1144 isolates that tested positive during initial screening, 593 had confirmed INA at -8 °C in repeated tests. Concentrations of Ice + strains in precipitation were found to range from 0 to 13 219 colony forming units per liter, with a mean of 384±147. Most Ice + bacteria were identified as members of known and unknown Ice + species in the Pseudomonadaceae, Enterobacteriaceae and Xanthomonadaceae families, which nucleate ice employing the well-characterized membrane-bound INA protein. Two Ice + strains, however, were identified as Lysinibacillus, a Gram-positive genus not previously known to include Ice + bacteria. INA of the Lysinibacillus strains is due to a nanometer-sized molecule that is heat resistant, lysozyme and proteinase resistant, and secreted. Ice + bacteria and the INA mechanisms they employ are thus more diverse than expected. We discuss to what extent the concentration of culturable Ice + bacteria in precipitation and the identification of a new heat-resistant biological INA mechanism support a role for Ice + bacteria in the initiation of precipitation.

Decolorization of basic dye solutions by electrocoagulation: an investigation of the effect of operational parameters.

PubMed

Daneshvar, N; Oladegaragoze, A; Djafarzadeh, N

2006-02-28

Electrocoagulation (EC) is one of the most effective techniques to remove color and organic pollutants from wastewater, which reduces the sludge generation. In this paper, electrocoagulation has been used for the removal of color from solutions containing C. I. Basic Red 46 (BR46) and C. I. Basic Blue 3 (BB3). These dyes are used in the wool and blanket factories for fiber dyeing. The effect of operational parameters such as current density, initial pH of the solution, time of electrolysis, initial dye concentration and solution conductivity were studied in an attempt to reach higher removal efficiency. The findings in this study shows that an increase in the current density up to 60-80 A m(-2) enhanced the color removal efficiency, the electrolysis time was 5 min and the range of pH was determined between 5.5 and 8.5 for two mentioned dye solutions. It was found that for, the initial concentration of dye in solutions should not be higher than 80 mg l(-1) in order to achieve a high color removal percentage. The optimum conductivity was found to be 8 mS cm(-1), which was adjusted using proper amount of NaCl with the dye concentration of 50 mg l(-1). Electrical energy consumption in the above conditions for the decolorization of the dye solutions containing BR46 and BB3 were 4.70 kWh(kgdye removed)(-1) and 7.57 kWh(kgdye removed)(-1), respectively. Also, during the EC process under the optimized conditions, the COD decreased by more than 75% and 99% in dye solutions containing BB3 and BR46, respectively.

Bilirubin glucuronidation revisited: proper assay conditions to estimate enzyme kinetics with recombinant UGT1A1.

PubMed

Zhou, Jin; Tracy, Timothy S; Remmel, Rory P

2010-11-01

Bilirubin, an end product of heme catabolism, is primarily eliminated via glucuronic acid conjugation by UGT1A1. Impaired bilirubin conjugation, caused by inhibition of UGT1A1, can result in clinical consequences, including jaundice and kernicterus. Thus, evaluation of the ability of new drug candidates to inhibit UGT1A1-catalyzed bilirubin glucuronidation in vitro has become common practice. However, the instability of bilirubin and its glucuronides presents substantial technical challenges to conduct in vitro bilirubin glucuronidation assays. Furthermore, because bilirubin can be diglucuronidated through a sequential reaction, establishment of initial rate conditions can be problematic. To address these issues, a robust high-performance liquid chromatography assay to measure both bilirubin mono- and diglucuronide conjugates was developed, and the incubation conditions for bilirubin glucuronidation by human embryonic kidney 293-expressed UGT1A1 were carefully characterized. Our results indicated that bilirubin glucuronidation should be assessed at very low protein concentrations (0.05 mg/ml protein) and over a short incubation time (5 min) to assure initial rate conditions. Under these conditions, bilirubin total glucuronide formation exhibited a hyperbolic (Michaelis-Menten) kinetic profile with a K(m) of ∼0.2 μM. In addition, under these initial rate conditions, the relative proportions between the total monoglucuronide and the diglucuronide product were constant across the range of bilirubin concentration evaluated (0.05-2 μM), with the monoglucuronide being the predominant species (∼70%). In conclusion, establishment of appropriate incubation conditions (i.e., very low protein concentrations and short incubation times) is necessary to properly characterize the kinetics of bilirubin glucuronidation in a recombinant UGT1A1 system.

Dietary fish oil alters the lysophospholipid metabolomic profile and decreases urinary 11-dehydro thromboxane B₂ concentration in healthy Beagles.

PubMed

Hall, Jean A; Brockman, Jeffrey A; Jewell, Dennis E

2011-12-15

Increased concentrations of dietary fish oil and antioxidants have been shown previously to change circulating concentrations of individual fatty acids (FAs) and vitamin E. The purpose of this study was to further investigate the effects of vitamins E and C, in combination with dietary fish oil, on selected blood and urinary biomarkers. Fifty adult Beagle dogs (mean age 5.3 years, range 1.4-14.2 years) were randomized into five dietary treatment groups for 90 days. All foods were complete and balanced and met the nutrient profiles of AAFCO for adult dogs. For 60 days before study initiation, dogs consumed a pretrial food that contained 74 IU/kg vitaminE and 0mg/kg vitaminC. The five experimental foods were confirmed by analytical methods to contain ≥ 640 IU/kg vitaminE and 130 mg/kg vitaminC (as fed). Experimental foods ranged from low levels of EPA and DHA (pretrial food and lowest experimental food had 0.01% EPA and no detectable DHA) to the highest experimental food with 0.25% EPA and 0.17% DHA. Serum was analyzed for FAs, vitamin E, and cholesterol concentrations; urine was analyzed for 11-dehydro thromboxane B(2) (TXB(2)). Serum was also used for metabolomic analysis. FA intake ranged from 0.02 g/day EPA and 0.02 g/day DHA to 0.58 g/day EPA and 0.39 g/day DHA. Increasing dietary concentrations of EPA and DHA resulted in increased serum concentrations of EPA and DHA in a dose-dependent fashion. Greater dietary vitamin E intake resulted in increased serum vitamin E concentrations (P<0.01). Higher serum cholesterol was also associated with higher serum vitamin E concentrations (P<0.01). In turn, changes in serum cholesterol concentration were associated with diet-induced changes in serum FA concentrations (all P<0.01). At the beginning of the dietary treatment period the most significant predictor of urine 11-dehydro TXB(2) concentration was age, followed by lean-body mass. After dietary treatment with different amounts of fish oil, age (increases 11-dehydro TXB(2)) was followed by EPA concentration as a significant negative predictor of urine 11-dehydro TXB(2) concentration (increasing serum concentrations of EPA decrease 11-dehydro TXB(2)), and then lean-body mass (decreases 11-dehydro TXB(2)). Serum docosahexaenoyl-glycerophosphocholine concentration was increased by feeding fish oil in a dose-response manner. In summary, serum vitamin E concentration is enhanced primarily by feeding vitamin E and secondarily by serum cholesterol concentration. When feeding diets enriched with fish oil, the major negative predictor of urinary 11-dehydro TXB(2) concentration is serum EPA concentration. Plasma lysophospholipids can be dynamically regulated by dietary fish oil supplementation. Copyright © 2011 Elsevier B.V. All rights reserved.

Competitive Adsorption and Oxidation Behavior of Heavy Metals on nZVI Coated with TEOS.

PubMed

Eglal, Mahmoud M; Ramamurthy, Amruthur S

2015-11-01

Zero valent iron nanoparticle (nanofer ZVI) is a powerful substance due to its coating with tetraethyl orthosilicate (TEOS). Tetraethyl orthosilicate imparts higher reactivity and decreases particle agglomeration. The competitive removal and displacement of multi-metals are influenced by time, pH, and initial concentration, the presence and properties of competing metals ion in the solution. For both the isotherm and kinetic studies performed for multi-metal removal experiments, compared to Pb II and Cd II, Cu II experienced a higher removal rate during the initial 5 minutes. After 120 minutes, all metals achieved removal efficiency in the range of 95 to 99%. The results of single and competitive kinetic tests for all three metals during the initial 5 minutes indicated that the presence of other metals generally reduce removal efficiency of metals. Both kinetic test and electron dispersive spectroscope (EDS) studies found that Cu II gets removed faster than the other metals. Pseudo-second order behavior was noted for the multi-metal removal systems.

Effect of precursor concentration and spray pyrolysis temperature upon hydroxyapatite particle size and density.

PubMed

Cho, Jung Sang; Lee, Jeong-Cheol; Rhee, Sang-Hoon

2016-02-01

In the synthesis of hydroxyapatite powders by spray pyrolysis, control of the particle size was investigated by varying the initial concentration of the precursor solution and the pyrolysis temperature. Calcium phosphate solutions (Ca/P ratio of 1.67) with a range of concentrations from 0.1 to 2.0 mol/L were prepared by dissolving calcium nitrate tetrahydrate and diammonium hydrogen phosphate in deionized water and subsequently adding nitric acid. Hydroxyapatite powders were then synthesized by spray pyrolysis at 900°C and at 1500°C, using these calcium phosphate precursor solutions, under the fixed carrier gas flow rate of 10 L/min. The particle size decreased as the precursor concentration decreased and the spray pyrolysis temperature increased. Sinterability tests conducted at 1100°C for 1 h showed that the smaller and denser the particles were, the higher the relative densities were of sintered hydroxyapatite disks formed from these particles. The practical implication of these results is that highly sinterable small and dense hydroxyapatite particles can be synthesized by means of spray pyrolysis using a low-concentration precursor solution and a high pyrolysis temperature under a fixed carrier gas flow rate. © 2015 Wiley Periodicals, Inc.

The mechanism of zinc uptake by cultured rat liver cells.

PubMed Central

Taylor, J A; Simons, T J

1994-01-01

1. The initial rate of 65Zn uptake into cultured rat hepatocytes has been measured over a range of Zn2+ concentrations from 3 x 10(-10) M to 5 x 10(-6) M. Histidine and albumin were used to buffer Zn2+ ions at concentrations below 1 x 10(-6) M. 2. The results suggest there are two mechanisms for Zn2+ uptake; a high-affinity, saturable pathway, with a maximum velocity (Vmax) of 20-30 pmol (mg protein)-1 min-1 and a Michaelis-Menten constant (Km) of about 2 x 10(-9) M Zn2+ (with histidine), and a low-affinity, linear pathway, that only makes a significant contribution to Zn2+ uptake at Zn2+ concentrations above 1 x 10(-6) M. 3. Transport via the high-affinity pathway is dependent on the concentration of Zn2+ ions and not on the concentrations of Zn(2+)-ligand complexes, suggesting that Zn2+ is the transported species. 4. The affinity of the saturable pathway for Zn2+ is slightly lower in the presence of albumin, with a Km of about 1.3 x 10(-8) M. The reason for this is uncertain. PMID:8014898

Wet oxidation of real coke wastewater containing high thiocyanate concentration.

PubMed

Oulego, Paula; Collado, Sergio; Garrido, Laura; Laca, Adriana; Rendueles, Manuel; Díaz, Mario

2014-01-01

Coke wastewaters, in particular those with high thiocyanate concentrations, represent an important environmental problem because of their very low biodegradability. In this work, the treatment by wet oxidation of real coke wastewaters containing concentrations of thiocyanate above 17 mM has been studied in a 1-L semi-batch reactor at temperatures between 453 and 493 K, with total oxygen pressures in the range of 2.0-8.0 MPa. A positive effect of the matrix of real coke wastewater was observed, resulting in faster thiocyanate degradation than was obtained with synthetic wastewaters. Besides, the effect of oxygen concentration and temperature on thiocyanate wet oxidation was more noticeable in real effluents than in synthetic wastewaters containing only thiocyanate. It was also observed that the degree of mineralization of the matrix organic compounds was higher when the initial thiocyanate concentration increased. Taking into account the experimental data, kinetic models were obtained, and a mechanism implying free radicals was proposed for thiocyanate oxidation in the matrix considered. In all cases, sulphate, carbonates and ammonium were identified as the main reaction products of thiocyanate wet oxidation. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Systematics of Light Lithophile Elements (Li, Be, B) in Lunar Picritic Glasses

NASA Astrophysics Data System (ADS)

Shearer, C. K.; Layne, G. D.; Papike, J. J.

1993-07-01

Lunar picritic glasses are thought to be the product of either partial melting of the deep lunar mantle followed by rapid ascent [1,2] or polybaric partial melting initiated in the deep lunar mantle [3]. The near primary compositions of these volcanic glasses provide us with a unique perspective for evaluating mare basaltic magmatism and the characteristics and evolution of the lunar mantle. Because of their obvious importance in deciphering the evolution of the Earth-Moon system, we have initiated an extensive trace element study of these picritic glasses using ion microprobe techniques. Here, we report the initial results of light lithophile element (LLE) analyses of these glasses. This is the first reported study of LLE in lunar basalts. The LLE have only recently received attention in terrestrial basaltic systems [4-6]. Their correlations with other more routinely analyzed trace elements (Li:Yb or V, Be:Nd, B:K) in a variety of terrestrial mantle environments have yielded several important insights into mantle magmatism [4-6]. Ion microprobe analyses of the glasses were conducted using a Cameca 4f ion microprobe operated on the UNM campus. The light lithophile elements were analyzed under the following conditions: 10-kV O- primary beam, 8-nA primary beam current, 10-15-micrometer beam diameter, sample voltage offset of -70 +- 25 V, and a 150-micrometer secondary ion image field with a 33-micrometer field aperature inserted. Counting times included background (2 seconds), 30Si (2 seconds), 7Li (2 seconds), 9Be (4 seconds), and 11B (8 seconds). Each analysis involved 30 to 40 counting cycles. These counting times resulted in precision for Li of better than 1.2% and for B and Be of better than 2.2%. Standards for Li, Be, and B in basaltic glass matrices were kindly provided by J. Ryan [4-6]. Calibration curves (LLE/30Si x wt% SiO2 vs. LLE concentration) were originally defined by a minimum of five standards for each element and are linear for the concentration ranges found in the picritic lunar glasses. Picritic glasses analyzed in the initial study were from the Apollo 12, 14, 15, and 17 sites. This suite of glasses ranged in TiO2 from 0.3 to 17 wt%. All glasses had been previously analyzed for major and trace elements (REE, Cr, V, Sr, Ba, Co, Zr) by electron microprobe and ion microprobe [2]. The LLE show a wide range of variability with Li ranging from 1.2 to 23.8 ppm, Be ranging from 0.06 to 3.09 ppm, and B ranging from 0.20 to 3.87 ppm. Traverses across individual glass beads suggest they are homogeneous with regard to LLE. Except for the A17 VLT glasses and the A15 yellow glasses, the individual glass groups [1] show very limited LLE variability. LLE content is positively correlated to TiO2 content. LLE concentrations also parallel the enrichment of other lithophile elements such as Ba, Zr, Sr, and the REE. Unlike terrestrial basalts [4-6], the concentration of LLE in the picritic glasses is negatively correlated with SiO2 and MgO. B/Be ranges from 0.40 to 4.6. Over 85% of the analyzed glasses have B/Be between 0.9 and 3.0, similar to the average B/Be value of 3 for MORB [6]. Li/B and Li/Be values range from 3.2 to 30.8 and 2.7 to 41.7, respectively. These LLE ratios are not correlated with TiO2, but appear to be characteristic of individual sampling sites and therefore reflect subtle differences in the sources of the picritic magmas. The LLE and LLE ratios also indicate a KREEP component had been incorporated into some of these picritic magmas. Shearer and Papike [2] suggested this incorporation occurs in the zone of melting and reflected overturning of the LMO cumulate pile. The initial data reported here suggest that the LLE may be useful in deciphering the mare basalt record. Further analyses of these glasses will allow a more detailed comparison of picritic glass sources with mare basalt sources and a better interpretation of the compositional relationships among picritic glasses. Acknowledgments: SIMS analyses were performed at the UNM/SNL Ion Microprobe Facility, a joint operation of the Institute of Meteoritics, UNM, and Sandia National Laboratories. This research was funded by NASA grant NAGW-3347. References: [1] Delano J. W. (1986) Proc. LPSC, 16th, in JGR, XX D201-D213. [2] Shearer C. K. and Papike J. J. (1993) GCA, in review. [3] Longhi J. (1992) GCA, 56, 2235-2252. [4] Ryan J. G. and Langmuir C. H. (1987) GCA, 51, 1727- 1741. [5] Ryan J. G. and Langmuir C. H. (1988) GCA, 52, 237-244. [6] Ryan J. G. and Langmuir C. H. (1993) GCA, 57, 1489-1498.

Long-term effects of the iron-based phosphate binder, sucroferric oxyhydroxide, in dialysis patients.

PubMed

Floege, Jürgen; Covic, Adrian C; Ketteler, Markus; Mann, Johannes F E; Rastogi, Anjay; Spinowitz, Bruce; Chong, Edward M F; Gaillard, Sylvain; Lisk, Laura J; Sprague, Stuart M

2015-06-01

Hyperphosphatemia necessitates the use of phosphate binders in most dialysis patients. Long-term efficacy and tolerability of the iron-based phosphate binder, sucroferric oxyhydroxide (previously known as PA21), was compared with that of sevelamer carbonate (sevelamer) in an open-label Phase III extension study. In the initial Phase III study, hemo- or peritoneal dialysis patients with hyperphosphatemia were randomized 2:1 to receive sucroferric oxyhydroxide 1.0-3.0 g/day (2-6 tablets/day; n = 710) or sevelamer 2.4-14.4 g/day (3-18 tablets/day; n = 349) for 24 weeks. Eligible patients could enter the 28-week extension study, continuing the same treatment and dose they were receiving at the end of the initial study. Overall, 644 patients were available for efficacy analysis (n = 384 sucroferric oxyhydroxide; n = 260 sevelamer). Serum phosphorus concentrations were maintained during the extension study. Mean ± standard deviation (SD) change in serum phosphorus concentrations from extension study baseline to Week 52 end point was 0.02 ± 0.52 mmol/L with sucroferric oxyhydroxide and 0.09 ± 0.58 mmol/L with sevelamer. Mean serum phosphorus concentrations remained within Kidney Disease Outcomes Quality Initiative target range (1.13-1.78 mmol/L) for both treatment groups. Mean (SD) daily tablet number over the 28-week extension study was lower for sucroferric oxyhydroxide (4.0 ± 1.5) versus sevelamer (10.1 ± 6.6). Patient adherence was 86.2% with sucroferric oxyhydroxide versus 76.9% with sevelamer. Mean serum ferritin concentrations increased over the extension study in both treatment groups, but transferrin saturation (TSAT), iron and hemoglobin concentrations were generally stable. Gastrointestinal-related adverse events were similar and occurred early with both treatments, but decreased over time. The serum phosphorus-lowering effect of sucroferric oxyhydroxide was maintained over 1 year and associated with a lower pill burden, compared with sevelamer. Sucroferric oxyhydroxide was generally well tolerated long-term and there was no evidence of iron accumulation. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA.

U-Th systematics and 230Th ages of carbonate chimneys at the Lost City Hydrothermal Field

NASA Astrophysics Data System (ADS)

Ludwig, Kristin A.; Shen, Chuan-Chou; Kelley, Deborah S.; Cheng, Hai; Edwards, R. Lawrence

2011-04-01

The Lost City Hydrothermal Field (LCHF) is a serpentinite-hosted vent field located 15 km west of the spreading axis of the Mid-Atlantic Ridge. In this study, uranium-thorium (U-Th) geochronological techniques have been used to examine the U-Th systematics of hydrothermal fluids and the 230Th ages of hydrothermally-precipitated carbonate chimneys at the LCHF. Fluid sample analyses indicate that endmember fluids likely contain only 0.0073 ng/g U or less compared to 3.28 ± 0.03 ng/g of U in ambient seawater. For fluid samples containing only 2-21% ambient seawater (1.1-11 mmol/kg Mg), Th concentration is 0.11-0.13 pg/g and surrounding seawater concentrations average 0.133 ± 0.016 pg/g. The 230Th/ 232Th atomic ratios of the vent fluids range from 1 (±10) × 10 -6 to 11 (±5) × 10 -6, are less than those of seawater, and indicate that the vent fluids may contribute a minor amount of non-radiogenic 230Th to the LCHF carbonate chimney deposits. Chimney 238U concentrations range from 1 to 10 μg/g and the average chimney corrected initial δ 234U is 147.2 ± 0.8, which is not significantly different from the ambient seawater value of 146.5 ± 0.6. Carbonate 232Th concentrations range broadly from 0.0038 ± 0.0003 to 125 ± 16 ng/g and 230Th/ 232Th atomic ratios vary from near seawater values of 43 (±8) × 10 -6 up to 530 (±25) × 10 -3. Chimney ages, corrected for initial 230Th, range from 17 ± 6 yrs to 120 ± 13 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all <4 kyrs old, indicating that mass wasting in this region is relatively recent. Comparison of results to prior age-dating investigations of submarine hydrothermal systems shows that the LCHF is the most long-lived hydrothermal system known to date. It is likely that seismic activity and active faulting within the Atlantis Massif and the Atlantis Fracture Zone, coupled with volumetric expansion of the underlying serpentinized host rocks play major roles in sustaining hydrothermal activity at this site. The longevity of venting at the LCHF may have implications for ecological succession of microorganisms within serpentinite-hosted vent environments.

Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

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

Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.

The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analyzing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analyzed period corresponds to the wet seasonmore » (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D ≤ 50 µm in order to capture the processes leading up to the precipitation formation. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40 % for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km –1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (> 20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision–coalescence process. The overall shape of the droplet size distribution (DSD) does not appear to be predominantly determined by updraught strength, especially beyond the 20 µm range. The aerosol conditions play a major role in that case. However, the updraughts modulate the DSD concentrations and are responsible for the vertical transport of water in the cloud. The larger droplets found in background clouds are associated with weak water vapour competition and a bimodal distribution of droplet sizes in the lower levels of the cloud, which enables an earlier initiation of the collision–coalescence process. This paper shows that the pollution produced by Manaus significantly affects warm-phase microphysical properties of the surrounding clouds by changing the initial DSD formation. The corresponding effects on ice-phase processes and precipitation formation will be the focus of future endeavors.« less

Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

DOE PAGES

Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.; ...

2016-06-09

The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analyzing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analyzed period corresponds to the wet seasonmore » (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D ≤ 50 µm in order to capture the processes leading up to the precipitation formation. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40 % for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km –1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (> 20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision–coalescence process. The overall shape of the droplet size distribution (DSD) does not appear to be predominantly determined by updraught strength, especially beyond the 20 µm range. The aerosol conditions play a major role in that case. However, the updraughts modulate the DSD concentrations and are responsible for the vertical transport of water in the cloud. The larger droplets found in background clouds are associated with weak water vapour competition and a bimodal distribution of droplet sizes in the lower levels of the cloud, which enables an earlier initiation of the collision–coalescence process. This paper shows that the pollution produced by Manaus significantly affects warm-phase microphysical properties of the surrounding clouds by changing the initial DSD formation. The corresponding effects on ice-phase processes and precipitation formation will be the focus of future endeavors.« less

Agronomic and environmental consequences of using liquid mineral concentrates on arable farms.

PubMed

Schils, René L M; Postma, Romke; van Rotterdam, Debby; Zwart, Kor B

2015-12-01

In regions with intensive livestock systems, the processing of manure into liquid mineral concentrates is seen as an option to increase the nutrient use efficiency of manures. The agricultural sector anticipates that these products may in future be regarded as regular mineral fertilisers. We assessed the agronomic suitability and impact on greenhouse gas (GHG) and ammonia emissions of using liquid mineral concentrates on arable farms. The phosphate requirements on arable farms were largely met by raw pig slurry, given its large regional availability. After the initial nutrient input by means of pig slurry, the nitrogen/phosphate ratio of the remaining nutrient crop requirements determined the additional amount of liquid mineral concentrates that can be used. For sandy soils, liquid mineral concentrates could supply 50% of the nitrogen requirement, whereas for clay soils the concentrates did not meet the required nitrogen/phosphate ratio. The total GHG emissions per kg of plant available nitrogen ranged from -65 to 33 kg CO2 -equivalents. It increased in the order digestates < mineral fertiliser < raw slurries. Liquid mineral concentrates had limited added value for arable farms. For an increased suitability it is necessary that liquid mineral concentrates do not contain phosphate and that the nitrogen availability is increased. In the manure-processing chain, anaerobic digestion had a dominant and beneficial effect on GHG emissions. © 2015 Society of Chemical Industry.

Population Pharmacokinetic Analysis and Model-Based Simulations of Aripiprazole for a 1-Day Initiation Regimen for the Long-Acting Antipsychotic Aripiprazole Lauroxil.

PubMed

Hard, Marjie L; Wehr, Angela Y; Sadler, Brian M; Mills, Richard J; von Moltke, Lisa

2018-06-11

BACKGROUND AND OBJECTIVES: Aripiprazole lauroxil (AL), a long-acting injectable antipsychotic for the treatment of schizophrenia, requires 21 days of oral aripiprazole supplementation upon initiation (21-day initiation regimen). An alternative 1-day initiation regimen utilizing a nano-crystalline milled dispersion of AL (AL NCD ) plus a single 30 mg oral aripiprazole dose achieved aripiprazole concentrations associated with therapeutic doses of aripiprazole in the same time frame as the 21-day initiation regimen when starting AL (441 or 882 mg). A population pharmacokinetic (PopPK) model was developed to describe aripiprazole pharmacokinetics following administration of AL NCD , AL and oral aripiprazole, and evaluate dosing scenarios likely to be encountered in clinical practice. In total, 12,768 plasma aripiprazole concentrations from 343 patients (from 4 clinical studies) were included in the PopPK analysis and used to construct the model. Concomitant administration of the 1-day initiation regimen with all approved AL dosing regimens (441, 662, or 882 mg monthly, 882 mg every 6 weeks, or 1064 mg every 2 months) is predicted to achieve aripiprazole concentrations associated with therapeutic doses of AL using the 21-day initiation regimen within 4 days, maintaining these concentrations until the next AL dose. Administration of the first AL injection 10 days after the 1-day initiation regimen resulted in median aripiprazole concentrations just before the second dose of AL ≥ 77% of that when coadministered on the same day. Coadministration of AL with a single AL NCD injection was predicted to be effective in rapidly re-establishing concentrations associated with therapeutic doses of AL following dose delay. Model-based simulations demonstrate that the 1-day initiation regimen is suitable for starting treatment with all AL doses, allowing a window of ≤ 10 days between initiation and AL administration. AL NCD may also be used to re-establish concentrations associated with therapeutic doses of AL in conjunction with a delayed AL dose.

Clinical and serological response of wild dogs (Lycaon pictus) to vaccination against canine distemper, canine parvovirus infection and rabies.

PubMed

van Heerden, J; Bingham, J; van Vuuren, M; Burroughs, R E J; Stylianides, E

2002-03-01

Wild dogs Lycaon pictuis (n = 8) were vaccinated 4 times against canine distemper (n = 8) (initially with inactivated and subsequently with live attenuated strains of canine distemper) and canine parvovirus infection (n = 8) over a period of 360 days. Four of the wild dogs were also vaccinated 3 times against rabies using a live oral vaccine and 4 with an inactivated parenteral vaccine. Commercially-available canine distemper, canine parvovirus and parenteral rabies vaccines, intended for use in domestic dogs, were used. None of the vaccinated dogs showed any untoward clinical signs. The inactivated canine distemper vaccine did not result in seroconversion whereas the attenuated live vaccine resulted in seroconversion in all wild dogs. Presumably protective concentrations of antibodies to canine distemper virus were present in all wild dogs for at least 451 days. Canine parvovirus haemagglutination inhibition titres were present in all wild dogs prior to the administration of vaccine and protective concentrations persisted for at least 451 days. Vaccination against parvovirus infection resulted in a temporary increase in canine parvovirus haemagglutination inhibition titres in most dogs. Administration of both inactivated parenteral and live oral rabies vaccine initially resulted in seroconversion in 7 of 8 dogs. These titres, however, dropped to very low concentrations within 100 days. Booster administrations resulted in increased antibody concentrations in all dogs. It was concluded that the vaccines were safe to use in healthy subadult wild dogs and that a vaccination protocol in free-ranging wild dogs should at least incorporate booster vaccinations against rabies 3-6 months after the first inoculation.

Ni(II) removal from aqueous solutions using cone biomass of Thuja orientalis.

PubMed

Malkoc, Emine

2006-09-21

The biomass of terrestrial-plant materials has high removal capacities for a number of heavy metal ions. The Ni(II) biosorption capacity of the cone biomass of Thuja orientalis was studied in the batch mode. The biosorption equilibrium level was determined as a function of contact time, pH, temperature, agitation speed at several initial metal ion and adsorbent concentrations. The removal of Ni(II) from aqueous solutions increased with adsorbent concentration, temperature and agitation speed of the solution were increased. The biosorption process was very fast; 90% of biosorption occurred within 3 min and equilibrium was reached at around 7 min. It is found that the biosorption of Ni(II) on the cone biomass was correlated well (R2 > 0.99) with the Langmuir equation as compared to Freundlich, BET Temkin and D-R isotherm equation under the concentration range studied. According to Langmuir isotherm, the monolayer saturation capacity (Q(o)) is 12.42 mg g(-1). The pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were applied to test the experimental data for initial Ni(II) and cone biomass concentrations. The pseudo-second-order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first-order and intraparticle diffusion kinetic models. The activation energy of biosorption (E(a)) was determined as 36.85 kJ mol(-1) using the Arrhenius equation. This study indicated that the cone biomass of T. orientalis can be used as an effective and environmentally friendly adsorbent for the treatment of Ni(II) containing aqueous solutions.

Aerobic TCE degradation by encapsulated toluene-oxidizing bacteria, Pseudomonas putida and Bacillus spp.

PubMed

Kim, Seungjin; Bae, Wookeun; Hwang, Jungmin; Park, Jaewoo

2010-01-01

The degradation rates of toluene and trichloroethylene (TCE) by Pseudomonas putida and Bacillus spp. that were encapsulated in polyethylene glycol (PEG) polymers were evaluated in comparison with the results of exposure to suspended cultures. PEG monomers were polymerized together with TCE-degrading microorganisms, such that the cells were encapsulated in and protected by the matrices of the PEG polymers. TCE concentrations were varied from 0.1 to 1.5 mg/L. In the suspended cultures of P. putida, the TCE removal rate decreased as the initial TCE concentration increased, revealing TCE toxicity or a limitation of reducing power, or both. When the cells were encapsulated, an initial lag period of about 10-20 h was observed for toluene degradation. Once acclimated, the encapsulated P. putida cultures were more tolerant to TCE at an experimental range of 0.6-1.0 mg/L and gave higher transfer efficiencies (mass TCE transformed/mass toluene utilized). When the TCE concentration was low (e.g., 0.1 mg/L) the removal of TCE per unit mass of cells (specific removal) was significantly lower, probably due to a diffusion limitation into the PEG pellet. Encapsulated Bacillus spp. were able to degrade TCE cometabolically. The encapsulated Bacillus spp. gave significantly higher values than did P. putida in the specific removal and the transfer efficiency, particularly at relatively high TCE concentration of approximately 1.0±0.5 mg/L. The transfer efficiency by encapsulated Bacillus spp. in this study was 0.27 mgTCE/mgToluene, which was one to two orders of magnitude greater than the reported values.

Incidence of Abnormal Liver Biochemical Tests in Hyperthyroidism

PubMed Central

Lin, Tiffany Y.; Shekar, Anshula O.; Li, Ning; Yeh, Michael W.; Saab, Sammy; Wilson, Mark; Leung, Angela M.

2017-01-01

Objective Abnormal serum liver function tests are common in patients with untreated thyrotoxicosis, even prior to the initiation of antithyroidal medications that may worsen their severity. There is a wide range of the incidence of these abnormalities in the published literature. The aim of this study was to assess the risks factors and threshold of thyrotoxicosis severity for developing an abnormal liver biochemical test upon the diagnosis of new thyrotoxicosis. Design Single-institution retrospective cohort study. Patients Patients ≥18 years old receiving medical care at a large, academic, urban U.S. medical center between 2002–2016. Measurements Inclusion criteria were a serum thyroid stimulating hormone [TSH] concentration < 0.3 mIU/L or ICD-9 code for thyrotoxicosis, with thyrotoxicosis confirmed by either a concurrent elevated serum triiodothyronine (T3) and/or thyroxine (T4) concentration [total or free] within 3 months), and an available liver biochemical test(s) within 6 months of thyrotoxicosis. The biochemical liver tests assessed were serum aspartate transaminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma-glutamyltransferase (GGT), total bilirubin, and conjugated bilirubin concentrations. Results In this cohort of 1,514 subjects, the overall incidence of any biochemical liver test abnormality within 6 months of thyrotoxicosis was 39%. An initial serum TSH concentration <0.02 mIU/L, male gender, and African-American race were significant predictors of an abnormal serum liver biochemical test within 6 months of the diagnosis of new-onset untreated thyrotoxicosis. Conclusions This study identifies risk factors for patients who develop an abnormal serum liver biochemical test result within 6 months of a diagnosis of untreated thyrotoxicosis. PMID:28199740

Boron removal and its concentration in aqueous solution through progressive freeze concentration.

PubMed

Wang, Li Pang

2017-09-01

This study explored the feasibility of progressive freeze concentration in boron removal and its concentration in aqueous solution. The influence of three key parameters in progressive freeze concentration on boron removal and concentration, namely, the advance speed of the ice front, the circumferential velocity of the stirrer, and the initial boron concentration, are investigated by conducting batch experiments. The results show that the effectiveness of boron removal increases with a lower advance speed of the ice front, a higher circumferential velocity of the stirrer, and a lower initial boron concentration. For a model boron solution with an initial concentration of 100 mg/L, the boron concentration in the ice phase after progressive freeze concentration is below 1 mg/L when the advance speed of the ice front is lower than 1 cm/h and the circumferential velocity of the stirrer is higher than 0.12 m/s. In addition, the concentration of boron in the liquid phase occurs simultaneously with progressive freeze concentration. Furthermore, the results also suggest that this method can be applied to the purification and concentration of not only organic molecules but also inorganic ions.

Explosive Leidenfrost droplets

NASA Astrophysics Data System (ADS)

Colinet, Pierre; Moreau, Florian; Dorbolo, Stéphane

2017-11-01

We show that Leidenfrost droplets made of an aqueous solution of surfactant undergo a violent explosion in a wide range of initial volumes and concentrations. This unexpected behavior turns out to be triggered by the formation of a gel-like shell, followed by a sharp temperature increase. Comparing a simple model of the radial surfactant distribution inside a spherical droplet with experiments allows highlighting the existence of a critical surface concentration for the shell to form. The temperature rise (attributed to boiling point elevation with surface concentration) is a key feature leading to the explosion, instead of the implosion (buckling) scenario reported by other authors. Indeed, under some conditions, this temperature increase is shown to be sufficient to trigger nucleation and growth of vapor bubbles in the highly superheated liquid bulk, stretching the surrounding elastic shell up to its rupture limit. The successive timescales characterizing this explosion sequence are also discussed. Funding sources: F.R.S. - FNRS (ODILE and DITRASOL projects, RD and SRA positions of P. Colinet and S. Dorbolo), BELSPO (IAP 7/38 MicroMAST project).

Nectar regulation in Euphorbia tithymaloides L., a hummingbird-pollinated Euphorbiaceae.

PubMed

Veiga Blanco, T; Galetto, L; Machado, I C

2013-09-01

Floral sexual phases can differ in nectar production and might be under selective pressure by pollinators. We studied Euphorbia tithymaloides, which has inflorescences that are initially female and then hermaphroditic. Volume and concentration of nectar were measured in both stages. Nectar production and the effect of extractions were determined using sets of bagged inflorescences; inflorescences in the hermaphroditic phase had higher values of nectar concentration, volume and sugar mass than inflorescences in the female phase. Nectar resorption was detected in senescent inflorescences. To test for homeostatic nectar regulation, artificial nectar was added and the response assessed after 24 h. The experiments showed that concentration and sugar mass are regulated within a narrow range, and the homeostatic points differ between the two sexual phases. These differences in nectar can be detected by hummingbirds, which prefer the female stage. Resorption and secretion seem to be part of a homeostatic mechanism by which nectar attributes are maintained to optimise sugar recovery. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pancreatic cholera syndrome: effect of a synthetic somatostatin analog on intestinal water and ion transport.

PubMed

Santangelo, W C; O'Dorisio, T M; Kim, J G; Severino, G; Krejs, G J

1985-09-01

The effect of a synthetic somatostatin analog was studied in a patient with severe secretory diarrhea due to pancreatic cholera syndrome. Basal intestinal perfusion studies indicated an absence of water and sodium absorption, and active chloride secretion in the small bowel. Intravenous administration of the somatostatin analog (1 microgram/kg.h) changed zero net water movement to absorption (122 mL/30 cm of the jejunum per hour). Chloride secretion changed to absorption (5.0 to 7.9 meq/30 cm.h), and plasma vasoactive intestinal polypeptide concentration was reduced from 330 to 45 pmol/L (normal, less than 51). When the analog was given subcutaneously, 100 micrograms twice daily, stool weight decreased, and plasma vasoactive intestinal polypeptide concentration fell toward the normal range (67 pmol/L). Plasma concentration of pancreatic polypeptide was initially elevated and dropped during intravenous infusion of somatostatin analog but returned to baseline on maintenance therapy with the analog delivered subcutaneously. The patient has not had further diarrhea during 9 months of therapy.

Transient phenomena in the pulse radiolysis of retinyl polyenes. 5. Association of radical cations with parent molecules

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

Bobrowski, K.; Das, P.K.

1986-02-27

At relatively high concentrations (1-10 mM) in O/sub 2/-saturated acetone, pulse radiolysis of all-trans-retinal, -retinoic acid, and -methyl retinoate gives rise to fast transient absorption processes that are best explained in terms of association of radical cations with parent polyenes to form dimers. From the concentration dependence of initial decay/formation kinetics, equilibrium constants (K) for monomer/dimer interconversion are measured to be 220-440 M/sup -1/ (in acetone). On going from acetone to 1,2-dichloroethane, K values for retinal and retinoic acid increase almost by an order of magnitude. For all trans-retinol and retinyl acetate, radical cation dimer formation appears to be negligiblemore » in the concentration range 1-10 mM of the polyene substrates (based on the lack of transient absorption changes seen with retinal and retinoic acid/ester). 24 references, 6 figures, 1 table.« less

Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth.

PubMed

Manoharan, V; Loganathan, P; Tillman, R W; Parfitt, R L

2007-02-01

A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF2(1+) and AlF(2+) complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future.

Stability and nuclear dynamics of the Bicoid morphogen gradient

PubMed Central

Gregor, Thomas; Wieschaus, Eric F.; McGregor, Alistair P.; Bialek, William; Tank, David W.

2008-01-01

Patterning in multicellular organisms results from spatial gradients in morphogen concentration, but the dynamics of these gradients remains largely unexplored. We characterize, through in vivo optical imaging, the development and stability of the Bicoid morphogen gradient in Drosophila embryos that express a Bicoid-eGFP fusion protein. The gradient is established rapidly (~1 hour after fertilization) with nuclear Bicoid concentration rising and falling during mitosis. Interphase levels result from a rapid equilibrium between Bicoid uptake and removal. Initial interphase concentration in nuclei in successive cycles is constant (±10%), demonstrating a form of gradient stability, but subsequently decays by approximately 30%. Both direct photobleaching measurements and indirect estimates of Bicoid-eGFP diffusion constants (D ≤ 1 μm2/s), provide a consistent picture of Bicoid transport on short (~min) time scales, but challenge traditional models of long range gradient formation. A new model is presented emphasizing the possible role of nuclear dynamics in shaping and scaling the gradient. PMID:17632061

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

PubMed

van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

2016-09-30

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of maternal exposure to phthalates and bisphenol A during pregnancy on gestational age.

PubMed

Weinberger, Barry; Vetrano, Anna M; Archer, Faith E; Marcella, Stephen W; Buckley, Brian; Wartenberg, Daniel; Robson, Mark G; Klim, Jammie; Azhar, Sana; Cavin, Sarah; Wang, Lu; Rich, David Q

2014-03-01

Phthalates and bisphenol A (BPA) are ubiquitous environmental toxicants, present in high concentrations in numerous consumer products. We hypothesized that maternal exposure to phthalates and BPA in pregnancy is associated with shortened gestation. Urinary phthalate and BPA metabolites from 72 pregnant women were measured at the last obstetric clinic visit prior to delivery. Using linear regression models, we estimated the change in gestational age associated with each interquartile range (IQR) increase in phthalate and BPA metabolite concentration. IQR increases in urinary mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and BPA concentrations were associated with 4.2 and 1.1 d decreases in gestation, respectively. When stratified by gender, these alterations were found only in male infants. We conclude that MEHHP and BPA (free + glucuronide) are associated with reductions in gestation, with effects observed only in males. Our findings are consistent with the idea that these agents induce gender-specific alterations in signaling via PPAR-γ transcription factor, androgen precursors and/or inflammatory mediators during the initiation of labor.

Removal of trivalent chromium from aqueous solution using aluminum oxide hydroxide.

PubMed

Bedemo, Agaje; Chandravanshi, Bhagwan Singh; Zewge, Feleke

2016-01-01

Water is second most essential for human being. Contamination of water makes it unsuitable for human consumption. Chromium ion is released to water bodies from various industries having high toxicity which affects the biota life in these waters. In this study aluminum oxide hydroxide was tested for its efficiency to remove trivalent chromium from aqueous solutions through batch mode experiments. Chromium concentrations in aqueous solutions and tannery waste water before and after adsorption experiments were determined using flame atomic absorption spectrometry. The effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(III) were studied. The study revealed that more than 99 % removal of Cr(III) was achieved over wide range of initial pH (3-10). The optimum conditions for the removal of Cr(III) were found to be at pH 4-6 with 40 g/L adsorbent dose at 60 min of contact time. The adsorption capacity was assessed using Langmuir and Freundlich isotherms. The equilibrium data at varying adsorbent dose obeyed the two isotherms. The adsorbent was found to be efficient for the removal of Cr(III) from tannery waste effluent.

[Analysis of antibiotic diffusion from agarose gel by spectrophotometry and laser interferometry methods].

PubMed

Arabski, Michał; Wasik, Sławomir; Piskulak, Patrycja; Góźdź, Natalia; Slezak, Andrzej; Kaca, Wiesław

2011-01-01

The aim of this study was to analysis of antibiotics (ampicilin, streptomycin, ciprofloxacin or colistin) release from agarose gel by spectrophotmetry and laser interferometry methods. The interferometric system consisted of a Mach-Zehnder interferometer with a He-Ne laser, TV-CCD camera, computerised data acquisition system and a gel system. The gel system under study consists of two cuvettes. We filled the lower cuvette with an aqueous 1% agarose solution with the antibiotics at initial concentration of antibiotics in the range of 0.12-2 mg/ml for spectrophotmetry analysis or 0.05-0.5 mg/ml for laser interferometry methods, while in the upper cuvette there was pure water. The diffusion was analysed from 120 to 2400 s with a time interval of deltat = 120 s by both methods. We observed that 0.25-1 mg/ml and 0,05 mg/ml are minimal initial concentrations detected by spectrophotometric and laser interferometry methods, respectively. Additionally, we observed differences in kinetic of antibiotic diffusion from gel measured by both methods. In conclusion, the laser interferometric method is a useful tool for studies of antibiotic release from agarose gel, especially for substances are not fully soluble in water, for example: colistin.

Stable isotope fractionation of selenium by natural microbial consortia

USGS Publications Warehouse

Ellis, A.S.; Johnson, T.M.; Herbel, M.J.; Bullen, T.D.

2003-01-01

The mobility and bioavailability of Se depend on its redox state, and reduction of Se oxyanions to less mobile, reduced species controls transport of this potentially toxic element in the environment. Stable isotope fractionation of Se is currently being developed as an indicator of Se immobilization through reduction. In this study, Se isotope fractionation resulting from reduction of Se(VI) and Se(IV) oxyanions by natural microbial consortia was measured in sediment slurry experiments under nearly natural conditions, with no substrate added. Experiments were conducted with a wide range of initial Se concentrations and with sediment and water from three locations with contrasting environmental settings. The products of Se(VI) and Se(IV) reduction were enriched in the lighter isotopes relative to the reactants. Shifts of -2.60/00 to -3.10/00 and -5.50/00 to -5.70/00, respectively, were observed in the 80Se/76Se ratio. These isotopic fractionations did not depend significantly on initial Se concentrations, which were varied from 22 μg/l to 8 mg/l, or on geochemical differences among the sediments. These results provide estimates of Se isotope fractionation in organic-rich wetland environments but may not be appropriate for substrate-poor aquifers and marine sediments.

Utilization of common ditch vegetation in the reduction of fipronil and its sulfone metabolite.

PubMed

Kröger, Robert; Moore, Matt T

2008-12-01

Fipronil, a phenylpyrazole insecticide, and its oxidative sulfone metabolite are two potential pollutants from treated rice and cotton production. A consequence of these pollutants occurring in surface runoff is degradation of downstream aquatic ecosystems. Utilization of primary intercept drainage ditches as management practices to reduce fipronil concentrations and loads has not been examined. This study used ditch mesocosms planted with monospecific stands of common emergent wetland vegetation to determine if certain plant species were more proficient in fipronil mitigation. Three replicates of four plant species were compared against a non-vegetated control to determine differences in water column outflow concentrations (microg L(-1)) and loads (microg). There were no significant differences between vegetated and control treatments in outflow concentrations (F = 0.35, P = 0.836) and loads (F = 0.35, P = 0.836). The range of fipronil reduction was 28-45% for both concentration and load. Unlike fipronil, fipronil sulfone concentrations and load increased by 96-328%. The increase in fipronil sulfone was hypothesized as a direct consequence of oxidation of fipronil within each mesocosm. The type of ditch vegetation had no effect on fipronil reduction. Future research needs to examine initial concentrations and hydraulic retention times to examine potential changes in reduction capacities.

Conceptual design of a self-deployable, high performance parabolic concentrator for advanced solar-dynamic power systems

NASA Astrophysics Data System (ADS)

Dehne, Hans J.

1991-05-01

NASA has initiated technology development programs to develop advanced solar dynamic power systems and components for space applications beyond 2000. Conceptual design work that was performed is described. The main efforts were the: (1) conceptual design of self-deploying, high-performance parabolic concentrator; and (2) materials selection for a lightweight, shape-stable concentrator. The deployment concept utilizes rigid gore-shaped reflective panels. The assembled concentrator takes an annular shape with a void in the center. This deployable concentrator concept is applicable to a range of solar dynamic power systems of 25 kW sub e to in excess of 75 kW sub e. The concept allows for a family of power system sizes all using the same packaging and deployment technique. The primary structural material selected for the concentrator is a polyethyl ethylketone/carbon fiber composite also referred to as APC-2 or Vitrex. This composite has a nearly neutral coefficient of thermal expansion which leads to shape stable characteristics under thermal gradient conditions. Substantial efforts were undertaken to produce a highly specular surface on the composite. The overall coefficient of thermal expansion of the composite laminate is near zero, but thermally induced stresses due to micro-movement of the fibers and matrix in relation to each other cause the surface to become nonspecular.

Microgravity Droplet Combustion in CO2 Enriched Environments at Elevated Pressures

NASA Technical Reports Server (NTRS)

Hicks, Michael C.; Nayagam, V.; Williams, F. A.

2007-01-01

Microgravity droplet combustion experiments were performed in elevated concentrations of CO2 at pressures of 1.0 atm, 3.0 atm, and 5.0 atm to examine the effects of a radiatively participating suppression agent in space applications. Methanol and n-heptane droplets, with an initial diameter of 2.0 mm supported on a quartz fiber, were used in these experiments. The ambient O2 concentration was held constant at 21% and the CO2 concentrations ranged from 0% to a maximum of 70%, by volume with the balance consisting of N2 . Results from the methanol tests showed slight decreases in burning rates with increased CO2 concentrations at all ambient pressures. The n-heptane tests show slight increases in burning rates with increasing CO2 concentrations at each pressure level. Instantaneous radiative heat flux was also measured using both a broadband radiometer (i.e., wavelengths from 0.6 microns to 40.0 microns) and a narrowband radiometer (i.e., centered at 5.6 microns with a filter width at half maximum of 1.5 microns). Radiative exchanges between the droplet and surrounding gases as well as the soot field produce departures from the classical quasisteady theory which would predict a decrease in burning rates with increasing CO2 concentrations in microgravity.

Conceptual design of a self-deployable, high performance parabolic concentrator for advanced solar-dynamic power systems

NASA Technical Reports Server (NTRS)

Dehne, Hans J.

1991-01-01

NASA has initiated technology development programs to develop advanced solar dynamic power systems and components for space applications beyond 2000. Conceptual design work that was performed is described. The main efforts were the: (1) conceptual design of self-deploying, high-performance parabolic concentrator; and (2) materials selection for a lightweight, shape-stable concentrator. The deployment concept utilizes rigid gore-shaped reflective panels. The assembled concentrator takes an annular shape with a void in the center. This deployable concentrator concept is applicable to a range of solar dynamic power systems of 25 kW sub e to in excess of 75 kW sub e. The concept allows for a family of power system sizes all using the same packaging and deployment technique. The primary structural material selected for the concentrator is a polyethyl ethylketone/carbon fiber composite also referred to as APC-2 or Vitrex. This composite has a nearly neutral coefficient of thermal expansion which leads to shape stable characteristics under thermal gradient conditions. Substantial efforts were undertaken to produce a highly specular surface on the composite. The overall coefficient of thermal expansion of the composite laminate is near zero, but thermally induced stresses due to micro-movement of the fibers and matrix in relation to each other cause the surface to become nonspecular.

An investigation using atomic force microscopy nanoindentation of dental enamel demineralization as a function of undissociated acid concentration and differential buffer capacity

NASA Astrophysics Data System (ADS)

Barbour, Michele E.; Shellis, R. Peter

2007-02-01

Acidic drinks and foodstuffs can demineralize dental hard tissues, leading to a pathological condition known as dental erosion, which is of increasing clinical concern. The first step in enamel dissolution is a demineralization of the outer few micrometres of tissue, which results in a softening of the structure. The primary determinant of dissolution rate is pH, but the concentration of undissociated acid, which is related to buffer capacity, also appears to be important. In this study, atomic force microscopy nanoindentation was used to measure the first initial demineralization (softening) induced within 1 min by exposure to solutions with a range of undissociated acid concentration and natural pH of 3.3 or with an undissociated acid concentration of 10 mmol l-1 and pH adjusted to 3.3. The results indicate that differential buffering capacity is a better determinant of softening than undissociated acid concentration. Under the conditions of these experiments, a buffer capacity of >3 mmol l-1 pH-1 does not have any further effect on dissolution rate. These results imply that differential buffering capacity should be used for preference over undissociated acid concentration or titratable acidity, which are more commonly employed in the literature.

Combustion of a Polymer (PMMA) Sphere in Microgravity

NASA Technical Reports Server (NTRS)

Yang, Jiann C.; Hamins, Anthony; Donnelly, Michelle K.

1999-01-01

A series of low gravity, aircraft-based, experiments was conducted to investigate the combustion of supported thermoplastic polymer spheres under varying ambient conditions. The three types of thermoplastic investigated were polymethylmethacrylate (PMMA), polypropylene (PP). and polystyrene (PS). Spheres with diameters ranging from 2 mm to 6.35 mm were tested. The total initial pressure varied from 0.05 MPa to 0. 15 MPa whereas the ambient oxygen concentration varied from 19 % to 30 % (by volume). The ignition system consisted of a pair of retractable energized coils. Two CCD cameras recorded the burning histories of the spheres. The video sequences revealed a number of dynamic events including bubbling and sputtering, as well as soot shell formation and break-up during combustion of the spheres at reduced gravity. The ejection of combusting material from the burning spheres represents a fire hazard that must be considered at reduced gravity. The ejection process was found to be sensitive to polymer type. All average burning rates were measured to increase with initial sphere diameter and oxygen concentration, whereas the initial pressure had little effect. The three thermoplastic types exhibited different burning characteristics. For the same initial conditions, the burning rate of PP was slower than PMMA, whereas the burning rate of PS was comparable to PMMA. The transient diameter of the burning thermoplastic exhibited two distinct periods: an initial period (enduring approximately half of the total burn duration) when the diameter remained approximately constant, and a final period when the square of the diameter linearly decreased with time. A simple homogeneous two-phase model was developed to understand the changing diameter of the burning sphere. Its value is based on a competition between diameter reduction due to mass loss from burning and sputtering, and diameter expansion due to the processes of swelling (density decrease with heating) and bubble growth. The model relies on empirical parameters for input, such as the burning rate and the duration of the initial and final burning periods.

Lead poisoning in dogs at the University of Pennsylvania Veterinary Hospital

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

Kowalczyk, D.F.

1976-03-01

Twenty-seven dogs with lead poisoning were admitted to the University of Pennsylvania Veterinary Hospital from July, 1963, to April, 1975. The major source of the lead was paint. A common history was ingestion of plaster or paint scrapings during room renovation. Most of the dogs were less than 1 year old and had clinical signs referable to the gastrointestinal or the nervous system, or both. The gastrointestinal signs, in order of frequency, were vomiting, anorexia, tender abdomen, diarrhea, and constipation. The neurologic signs, in order of frequency, were hysteria, convulsions, ataxia, blindness, and mydriasis. The finding of many nucleated erythrocytesmore » without severe anemia was nearly pathognomonic for lead poisoning. Of 14 affected dogs subjected to abdominal radiography, 9 had evidence of ingested radiopaque material. A mean blood lead concentration of 18.8 ..mu..g/100 ml, with a range of 0 to 50 ..mu..g/100 ml, was found for 26 dogs that were hospitalized for problems unrelated to lead poisoning. Of the 27 dogs with lead poisoning, 22 had their blood analyzed for lead. This group had blood lead values ranging from 40 to 530 ..mu..g/100 ml. Seven of the affected dogs were monitored throughout their period of treatment with calcium ethylene-diaminetetraacetate. The concentration of lead in the blood decreased quickly after the initiation and treatment but leveled off after 2 or 3 days. The initial rapid phase probably corresponded to the removal of weakly bound or extracellular lead, whereas the slow phase probably corresponded to strongly bound or intracellular lead. 22 references.« less

Effect of kaolin addition on the performance of controlled low-strength material using industrial waste incineration bottom ash.

PubMed

Naganathan, Sivakumar; Razak, Hashim Abdul; Hamid, Siti Nadzriah Abdul

2010-09-01

Incineration of industrial waste produces large quantities of bottom ash which are normally sent to secured landfill, but is not a sustainable solution. Use of bottom ash in engineering applications will contribute to sustainability and generate revenue. One way of using the industrial waste incineration bottom ash is in controlled low-strength material (CLSM). Use of bottom ash in CLSM has problems related to bleeding and excessive strength development and so an additive has to be used to control bleeding and strength development. The main objective of this research is to study the effect of kaolin addition on the performance of CLSM made using industrial waste incineration bottom ash. CLSM mixes were made with bottom ash, cement, and refined kaolin. Various tests were performed on the CLSM in fresh and hardened states including compressive strength, water absorption, California bearing ratio (CBR) and the tests for concentration of leachable substances on the bleed and leachate. The compressive strength of CLSM tested ranged from 0.11 to 9.86 MPa. CBR values ranged from 6 to 46, and water absorption values from 12 to 36%. It was shown that the addition of kaolin delayed the initial setting time of CLSM mixtures, reduced bleeding, lowered the compressive strength, and increased the values of water absorption, sorption, and initial surface absorption. The CLSM tested did not have corrosivity. It was shown that the hardened CLSM was non hazardous, and the addition of kaolin increased the concentration of heavy metals and salts in the bleed and leachate.

Warfarin and bosentan interaction in a patient with pulmonary hypertension secondary to bilateral pulmonary emboli.

PubMed

Spangler, Mikayla L; Saxena, Shailendra

2010-01-01

Bosentan is an endothelin-receptor antagonist that reportedly induces both cytochrome P450 (CYP) 3A4 and CYP2C9 enzymes, which are also involved in warfarin metabolism. We present a case report describing a probable drug interaction between warfarin and bosentan in a patient with pulmonary hypertension. A 52-year-old black female (weight, 77 kg) diagnosed with pulmonary hypertension secondary to bilateral pulmonary emboli had a stable international normalized ratio (INR; target range, 2-3) with a weekly warfarin dose of 52.5 mg for 2 months before the initiation of bosentan therapy. Other concurrent medications included telmisartan/ hydrochlorothiazide 40/12.5 mg once daily and a daily multivitamin (which contained no vitamin K). Three weeks after starting bosentan 62.5 mg BID, a therapeutic INR concentration was reached with a weekly warfarin dose 14% higher (an increase of 7.5 mg/wk) than her weekly warfarin dose before initiation of bosentan. After a brief discontinuation (7 days) and retitration of bosentan and warfarin, the final weekly warfarin dose (75 mg/wk) was 43% greater (an increase of 22.5 mg/wk) than the previously stable dose, which enabled the patient to reach her therapeutic INR goal range of 2 to 3. Bosentan has CYP3A4- and CYP2C9-inducing properties and is therefore likely to cause decreased concentrations of warfarin. We describe here a probable drug interaction between bosentan and warfarin that resulted in a 43% increase in warfarin dose to maintain the patient's therapeutic INR.

Cr(VI) removal from aqueous solution by thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1 in the presence of single and multiple heavy metals.

PubMed

Li, Han; Huang, Shaobin; Zhang, Yongqing

2016-09-01

Cr(VI) pollution is increasing continuously as a result of ongoing industrialization. In this study, we investigated the thermophilic denitrifying bacterium Chelatococcus daeguensis TAD1, isolated from the biofilm of a biotrickling filter used in nitrogen oxides (NOX) removal, with respect to its ability to remove Cr(VI) from an aqueous solution. TAD1 was capable of reducing Cr(VI) from an initial concentration of 10 mg/L to non-detectable levels over a pH range of 7-9 and at a temperature range of 30-50°C. TAD1 simultaneously removed both Cr(VI) and NO3 (-)-N at 50°C, when the pH was 7 and the initial Cr(VI) concentration was 15 mg/L. The reduction of Cr(VI) to Cr(III) correlated with the growth metabolic activity of TAD1. The presence of other heavy metals (Cu, Zn, and Ni) inhibited the ability of TAD1 to remove Cr(VI). The metals each individually inhibited Cr(VI) removal, and the extent of inhibition increased in a cooperative manner in the presence of a combination of the metals. The addition of biodegradable cellulose acetate microspheres (an adsorption material) weakened the toxicity of the heavy metals; in their presence, the Cr(VI) removal efficiency returned to a high level. The feasibility and applicability of simultaneous nitrate removal and Cr(VI) reduction by strain TAD1 is promising, and may be an effective biological method for the clean-up of wastewater.

Characteristics of flash initiations in a supercell cluster with tornadoes

NASA Astrophysics Data System (ADS)

Zheng, Dong; MacGorman, Donald R.

2016-01-01

Flash initiations within a supercell cluster during 10-11 May 2010 in Oklahoma were investigated based on observations from the Oklahoma Lightning Mapping Array and the Norman, Oklahoma, polarimetric radar (KOUN). The flash initiations at positions dominated by graupel, dry snow, small hail and crystals accounted for 44.3%, 44.1%, 8.0% and 3.0% of the total flashes, respectively. During the tornadic stage of the southern supercell in the cluster, flash initiations associated with graupel occupied the main body, the right flank and the forward flank of the supercell, while those associated with dry snow dominated the outskirts of the adjacent forward anvil, right anvil and rear anvil. The flash initiations associated with small hail were concentrated around the main updraft, particularly toward its front side. Highly dense flash initiations were located in the regions overlying the differential reflectivity (ZDR) arc and right anvil. The average initial height of the flashes decreased gradually from the rear to the front and from the right to the left flanks, while the height range over which initiations occurred reached a maximum at the front of the updraft. The flashes that were initiated in the adjacent forward anvils were largest on average, followed by those in the regions ahead of the updraft and near the ZDR arc. This study supports the concept of charge pockets and further deduces that the pockets in the right anvil are the most abundant and compact due to the frequent flash initiations, small-sized flashes and thin layers including flash initiations.

Titanium subhydride potassium perchlorate (TiH1.65/KClO4) burn rates from hybrid closed bomb-strand burner experiments.

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

Cooper, Marcia A.; Oliver, Michael S.

2012-08-01

A hybrid closed bomb-strand burner is used to measure the burning behavior of the titanium subhydride potassium perchlorate pyrotechnic with an equivalent hydrogen concentration of 1.65. This experimental facility allows for simultaneous measurement of the closed bomb pressure rise and pyrotechnic burn rate as detected by electrical break wires over a range of pressures. Strands were formed by pressing the pyrotechnic powders to bulk densities between 60% and 90% theoretical maximum density. The burn rate dependance on initial density and vessel pressure are measured. At all initial strand densities, the burn is observed to transition from conductive to convective burningmore » within the strand. The measured vessel pressure history is further analyzed following the closed bomb analysis methods developed for solid propellants.« less

Debris flows: behavior and hazard assessment

USGS Publications Warehouse

Iverson, Richard M.

2014-01-01

Debris flows are water-laden masses of soil and fragmented rock that rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form lobate deposits when they spill onto valley floors. Because they have volumetric sediment concentrations that exceed 40 percent, maximum speeds that surpass 10 m/s, and sizes that can range up to ~109 m3, debris flows can denude slopes, bury floodplains, and devastate people and property. Computational models can accurately represent the physics of debris-flow initiation, motion and deposition by simulating evolution of flow mass and momentum while accounting for interactions of debris' solid and fluid constituents. The use of physically based models for hazard forecasting can be limited by imprecise knowledge of initial and boundary conditions and material properties, however. Therefore, empirical methods continue to play an important role in debris-flow hazard assessment.

Coupling between fluid dynamics and energy addition in arcjet and microwave thrusters

NASA Technical Reports Server (NTRS)

Micci, M. M.

1986-01-01

A new approach to numerically solving the problem of the constricted electric arcjet is presented. An Euler Implicit finite difference scheme is used to solve the full compressible Navier Stokes equations in two dimensions. The boundary and initial conditions represent the constrictor section of the arcjet, and hydrogen is used as a propellant. The arc is modeled as a Gaussian distribution across the centerline of the constrictor. Temperature, pressure and velocity profiles for steady state converged solutions show both axial and radial changes in distributions resulting from their interaction with the arc energy source for specific input conditions. The temperature rise is largest at the centerline where there is a the greatest concentration arc energy. The solution does not converge for all initial inputs and the limitations in the range of obtainable solutions are discussed.

Groundwater quality and the relation between pH values and occurrence of trace elements and radionuclides in water samples collected from private wells in part of the Kickapoo Tribe of Oklahoma Jurisdictional Area, central Oklahoma, 2011

USGS Publications Warehouse

Becker, Carol J.

2013-01-01

From 1999 to 2007, the Indian Health Service reported that gross alpha-particle activities and concentrations of uranium exceeded the Maximum Contaminant Levels for public drinking-water supplies in water samples from six private wells and two test wells in a rural residential neighborhood in the Kickapoo Tribe of Oklahoma Jurisdictional Area, in central Oklahoma. Residents in this rural area use groundwater from Quaternary-aged terrace deposits and the Permian-aged Garber-Wellington aquifer for domestic purposes. Uranium and other trace elements, specifically arsenic, chromium, and selenium, occur naturally in rocks composing the Garber-Wellington aquifer and in low concentrations in groundwater throughout its extent. Previous studies have shown that pH values above 8.0 from cation-exchange processes in the aquifer cause selected metals such as arsenic, chromium, selenium, and uranium to desorb (if present) from mineral surfaces and become mobile in water. On the basis of this information, the U.S. Geological Survey, in cooperation with the Kickapoo Tribe of Oklahoma, conducted a study in 2011 to describe the occurrence of selected trace elements and radionuclides in groundwater and to determine if pH could be used as a surrogate for laboratory analysis to quickly and inexpensively identify wells that might contain high concentrations of uranium and other trace elements. The pH and specific conductance of groundwater from 59 private wells were measured in the field in an area of about 18 square miles in Lincoln and Pottawatomie Counties. Twenty of the 59 wells also were sampled for dissolved concentrations of major ions, trace elements, gross alpha-particle and gross beta-particle activities, uranium, radium-226, radium-228, and radon-222 gas. Arsenic concentrations exceeded the Maximum Contaminant Level of 10 micrograms per liter in one sample having a concentration of 24.7 micrograms per liter. Selenium concentrations exceeded the Maximum Contaminant Level of 50 micrograms per liter in one sample having a concentration of 147 micrograms per liter. Both samples had alkaline pH values, 8.0 and 8.4, respectively. Uranium concentrations ranged from 0.02 to 383 micrograms per liter with 5 of 20 samples exceeding the Maximum Contaminant Level of 30 micrograms per liter; the five wells with uranium concentrations exceeding 30 micrograms per liter had pH values ranging from 8.0 to 8.5. Concentrations of uranium and radon-222 and gross alpha-particle activity showed a positive relation to pH, with the highest concentrations and activity in samples having pH values of 8.0 or above. The groundwater samples contained dissolved oxygen and high concentrations of bicarbonate; these characteristics are also factors in increasing uranium solubility. Concentrations of radium-226 and radium-228 (combined) ranged from 0.03 to 1.7 picocuries per liter, with a median concentration of 0.45 picocuries per liter for all samples. Radon-222 concentrations ranged from 95 to 3,600 picocuries per liter with a median concentration of 261 picocuries per liter. Eight samples having pH values ranging from 8.0 to 8.7 exceeded the proposed Maximum Contaminant Level of 300 picocuries per liter for radon-222. Eight samples exceeded the 15 picocuries per liter Maximum Contaminant Level for gross alpha-particle activity at 72 hours (after sample collection) and at 30 days (after the initial count); those samples had pH values ranging from 8.0 to 8.5. Gross beta-particle activity increased in 15 of 21 samples during the interval from 72 hours to 30 days. The increase in gross beta-particle activity over time probably was caused by the ingrowth and decay of uranium daughter products that emit beta particles. Water-quality data collected for this study indicate that pH values above 8.0 are associated with potentially high concentrations of uranium and radon-222 and high gross alpha-particle activity in the study area. High pH values also are associated with potentially high concentrations of arsenic, chromium, and selenium in groundwater when these elements occur in the aquifer matrix along groundwater-flow paths.

Evaluation of efficacy of resin hemoperfusion in patients with acute 2,4-dinitrophenol poisoning by dynamic monitoring of plasma toxin concentration.

PubMed

Zhao, Xue-hong; Jiang, Jiu-kun; Lu, Yuan-qiang

2015-08-01

The intoxications caused by 2,4-dinitrophenol (2,4-DNP), even death, have been frequently reported in recent years. This study aims to investigate the dynamic changes of plasma toxin concentration and explore the clinical value of resin hemoperfusion (HP) in the treatment of patients with acute 2,4-DNP poisoning. We reported 16 cases of acute 2,4-DNP poisoning through occupational exposure due to ignoring the risk of poisoning. The blood samples were collected from the 14 survivors. According to the different treatments of resin HP, the survivors were divided into routine HP (n=5) and intensive HP (n=9) groups. Ultra high performance liquid chromatography/ tandem mass spectroscopy (UPLC-MS/MS) was used to detect the 2,4-DNP concentration in plasma in this study. The 14 survivors recovered very well after treatment. The initial plasma 2,4-DNP concentrations (C1) of survivors ranged from 0.25 to 41.88 µg/ml (mean (12.56±13.93) µg/ml). A positive correlation existed between initial plasma 2,4-DNP concentration (C1) and temperature. The elimination of 2,4-DNP was slow and persistent, and the total clearance rates of plasma toxin from the 1st to 3rd day (R3), the 3rd to 7th day (R3-7), and the 1st to 7th day (R7), were only (53.03±14.04)%, (55.25±10.50)%, and (78.29±10.22)%, respectively. The plasma toxin was cleared up to 25 d after poisoning in most of the patients. The R3, R3-7, and R7 in the intensive HP group were all apparently higher than those in the routine HP group, with statistical significance (P<0.05). Simultaneously, the elimination half-life (t1/2) of 2,4-DNP in the intensive HP group was apparently shorter than that in the routine HP group, with statistical significance (P<0.05). The clinicians should be aware of this slow and persistent process in the elimination of plasma 2,4-DNP. Higher initial plasma toxin concentration resulted in a more severe fever for the patient. According to the limited data, longer and more frequent resin HP may accelerate to eliminate the poison.

Long-term stability of dexamethasone and alizapride or ondansetron in sodium chloride 0.9% polyolefin bag at 5±3°C.

PubMed

Simar, J; Godet, M; Hecq, J-D; Closset, M; Gillet, P; Langhendries, C; Bihin, B; Jamart, J; Galanti, L

2017-01-01

The aim of the study was to investigate the long-term stability of dexamethasone 10mg associated with alizapride 100mg or ondansetron 8mg in 100mL of 0.9% sodium chloride solution stored at 5±3°C. Solutions of 0.9% sodium chloride 100mL in polyolefin bags (n=5) containing approximately dexamethasone (DEX) 10mg associated with alizapride (ALI) 100mg or ondansetron (OND) 8mg were prepared under aseptic conditions and stored about 30 days at 5±3°C. ALI, DEX and OND concentrations were measured by high-performance liquid chromatography (HPLC). Optic density measurement at different wavelengths, pH measurement and optic microscope observations were performed periodically during the storage. A forced degradation test with HCL 5M and NaOH 5M before and after heating at 100°C was also performed. Solutions were considered stable if the 95% one-sided lower confidence limit of the concentration remains superior to 90% of the initial concentration or 95% of the initial concentration when any signs of physical instability exist as recently recommend. The calibration was linear over the following range from 20 to 1.25mg/100mL for DEX, from 200 to 12.5mg/100mL for ALI and from 20 to 1.25mg/100mL for OND with a calculated correlation coefficient (r 2 ) of 0.998, 0.999 and 0.999, respectively. The inter- and intra-assay precision was below 10% for both mixtures. All formulations were physically stable during the storage. The lower confidence limit of the concentration for these solutions remains superior to 90% of the initial concentration at this date as recommended by the Food and Drug Administration (FDA) until 30 days. The HPLC method is specific and reproducible and can easily be adopted for monitoring the quality control in the production of DEX-ALI and DEX-OND bags. Solutions of DEX-ALI and DEX-OND were physically and chemically stable for 30 days in polyolefin bags stored at 5±3°C and could therefore be prepared in advance. Copyright © 2016 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado

NASA Astrophysics Data System (ADS)

Godt, Jonathan W.; Coe, Jeffrey A.

2007-02-01

On 28 July 1999, about 480 alpine debris flows were triggered by an afternoon thunderstorm along the Continental Divide in Clear Creek and Summit counties in the central Front Range of Colorado. The thunderstorm produced about 43 mm of rain in 4 h, 35 mm of which fell in the first 2 h. Several debris flows triggered by the storm impacted Interstate Highway 70, U.S. Highway 6, and the Arapahoe Basin ski area. We mapped the debris flows from color aerial photography and inspected many of them in the field. Three processes initiated debris flows. The first process initiated 11% of the debris flows and involved the mobilization of shallow landslides in thick, often well vegetated, colluvium. The second process, which was responsible for 79% of the flows, was the transport of material eroded from steep unvegetated hillslopes via a system of coalescing rills. The third, which has been termed the "firehose effect," initiated 10% of the debris flows and occurred where overland flow became concentrated in steep bedrock channels and scoured debris from talus deposits and the heads of debris fans. These three processes initiated high on steep hillsides (> 30°) in catchments with small contributing areas (< 8000 m 2), however, shallow landslides occurred on slopes that were significantly less steep than either overland flow process. Based on field observations and examination of soils mapping of the northern part of the study area, we identified a relation between the degree of soil development and the process type that generated debris flows. In general, areas with greater soil development were less likely to generate runoff and therefore less likely to generate debris flows by the firehose effect or by rilling. The character of the surficial cover and the spatially variable hydrologic response to intense rainfall, rather than a threshold of contributing area and topographic slope, appears to control the initiation process in the high alpine of the Front Range. Because debris flows initiated by rilling and the firehose effect tend to increase in volume as they travel downslope, these debris flows are potentially more hazardous than those initiated by shallow landslides, which tend to deposit material along their paths.

Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado

USGS Publications Warehouse

Godt, J.W.; Coe, J.A.

2007-01-01

On 28 July 1999, about 480 alpine debris flows were triggered by an afternoon thunderstorm along the Continental Divide in Clear Creek and Summit counties in the central Front Range of Colorado. The thunderstorm produced about 43??mm of rain in 4??h, 35??mm of which fell in the first 2??h. Several debris flows triggered by the storm impacted Interstate Highway 70, U.S. Highway 6, and the Arapahoe Basin ski area. We mapped the debris flows from color aerial photography and inspected many of them in the field. Three processes initiated debris flows. The first process initiated 11% of the debris flows and involved the mobilization of shallow landslides in thick, often well vegetated, colluvium. The second process, which was responsible for 79% of the flows, was the transport of material eroded from steep unvegetated hillslopes via a system of coalescing rills. The third, which has been termed the "firehose effect," initiated 10% of the debris flows and occurred where overland flow became concentrated in steep bedrock channels and scoured debris from talus deposits and the heads of debris fans. These three processes initiated high on steep hillsides (> 30??) in catchments with small contributing areas (< 8000??m2), however, shallow landslides occurred on slopes that were significantly less steep than either overland flow process. Based on field observations and examination of soils mapping of the northern part of the study area, we identified a relation between the degree of soil development and the process type that generated debris flows. In general, areas with greater soil development were less likely to generate runoff and therefore less likely to generate debris flows by the firehose effect or by rilling. The character of the surficial cover and the spatially variable hydrologic response to intense rainfall, rather than a threshold of contributing area and topographic slope, appears to control the initiation process in the high alpine of the Front Range. Because debris flows initiated by rilling and the firehose effect tend to increase in volume as they travel downslope, these debris flows are potentially more hazardous than those initiated by shallow landslides, which tend to deposit material along their paths. ?? 2006 Elsevier B.V. All rights reserved.

Effect of initial oil concentration and dispersant on crude oil biodegradation in contaminated seawater.

PubMed

Zahed, Mohammad Ali; Aziz, Hamidi Abdul; Isa, Mohamed Hasnain; Mohajeri, Leila

2010-04-01

The effects of initial oil concentration and the Corexit 9500 dispersant on the rate of bioremediation of petroleum hydrocarbons were investigated with a series of ex-situ seawater samples. With initial oil concentrations of 100, 500, 1,000 and 2,000 mg/L, removal of total petroleum hydrocarbons (TPHs) with dispersant were 67.3%, 62.5%, 56.5% and 44.7%, respectively, and were 64.2%, 55.7%, 48.8% and 37.6% without dispersant. The results clearly indicate that the presence of dispersant enhanced crude oil biodegradation. Lower concentrations of crude oil demonstrated more efficient hydrocarbon removal. Based on these findings, bioremediation is not recommended for crude oil concentrations of 2,000 mg/L or higher.

Inactivation of Mycobacterium avium with free chlorine.

PubMed

Luh, Jeanne; Mariñas, Benito J

2007-07-15

The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.

Stability of buffer-free freeze-dried formulations: A feasibility study of a monoclonal antibody at high protein concentrations.

PubMed

Garidel, Patrick; Pevestorf, Benjamin; Bahrenburg, Sven

2015-11-01

We studied the stability of freeze-dried therapeutic protein formulations over a range of initial concentrations (from 40 to 160 mg/mL) and employed a variety of formulation strategies (including buffer-free freeze dried formulations, or BF-FDF). Highly concentrated, buffer-free liquid formulations of therapeutic monoclonal antibodies (mAbs) have been shown to be a viable alternative to conventionally buffered preparations. We considered whether it is feasible to use the buffer-free strategy in freeze-dried formulations, as an answer to some of the known drawbacks of conventional buffers. We therefore conducted an accelerated stability study (24 weeks at 40 °C) to assess the feasibility of stabilizing freeze-dried formulations without "classical" buffer components. Factors monitored included pH stability, protein integrity, and protein aggregation. Because the protein solutions are inherently self-buffering, and the system's buffer capacity scales with protein concentration, we included highly concentrated buffer-free freeze-dried formulations in the study. The tested formulations ranged from "fully formulated" (containing both conventional buffer and disaccharide stabilizers) to "buffer-free" (including formulations with only disaccharide lyoprotectant stabilizers) to "excipient-free" (with neither added buffers nor stabilizers). We evaluated the impacts of varying concentrations, buffering schemes, pHs, and lyoprotectant additives. At the end of 24 weeks, no change in pH was observed in any of the buffer-free formulations. Unbuffered formulations were found to have shorter reconstitution times and lower opalescence than buffered formulations. Protein stability was assessed by visual inspection, sub-visible particle analysis, protein monomer content, charge variants analysis, and hydrophobic interaction chromatography. All of these measures found the stability of buffer-free formulations that included a disaccharide stabilizer comparable to buffer-based formulations, especially at protein concentrations up to and including 115 mg/mL. Copyright © 2015 Elsevier B.V. All rights reserved.

The influence of calcium supplementation on immobilised mixed microflora for biohydrogen production

NASA Astrophysics Data System (ADS)

Lutpi, Nabilah Aminah; Shian, Wong Yee; Izhar, Tengku Nuraiti Tengku; Zainol, Noor Ainee; Kiong, Yiek Wee

2017-04-01

This study is aim to study the effect of calcium as supplement in attached growth system towards the enhancement of the hydrogen production performance. The effects of calcium ion for thermophilic biohydrogen production were studied by using a mixed culture, from palm oil mill effluent sludge and granular activated carbon (GAC) as the support material. Batch experiments were carried out at 60°C by feeding the anaerobic sludge bacteria with sucrose-containing synthetic medium at an initial pH of 5.5 under anaerobic conditions. The repeated batch cultivation process was conducted by adding different concentration of calcium at range 0.025g/L to 0.15g/L. The results showed that the calcium at 0.1 g/L was the optimal concentration to enhance the fermentative hydrogen production under thermophilic (60°C) conditions.

Friction wear and auger analysis of iron implanted with 1.5-MeV nitrogen ions

NASA Technical Reports Server (NTRS)

Ferrante, J.; Jones, W. R., Jr.

1982-01-01

The effect of implantation of 1.5-MeV nitrogen ions on the friction and wear characteristics of pure iron sliding against steel was studied in a pin-on disk apparatus. An implantation dose of 5 x 10 to the 17th power ions/sq cm was used. Small reductions in initial and steady-state wear rates were observed for nitrogen-implanted iron riders as compared with unimplanted controls. Auger electron spectroscopy revealed a subsurface Gaussian nitrogen distribution with a maximum concentration of 15 at. % at a depth of 8 x 10 to the -7th m. A similar analysis within the wear scar of an implanted rider after 20 microns of wear yielded only background nitrogen concentration, thus giving no evidence for diffusion of nitrogen beyond the implanted range.

A Preliminary Study of Europium Uptake by Yeast Cells. The Case of Kluveromyces Marxianus

NASA Astrophysics Data System (ADS)

Anagnostopoulos, V.; Symeopoulos, B.

2008-08-01

The objective of the present work is an exploration of a cost effective recovery of lanthanides, either for minimizing the industrial processes losses, or for reasons related to Radioactive Waste Management. Specifically, the uptake of europium from aqueous solutions by Kluveromyces marxianus cells was studied. Moreover, this biotechnological approach turns out to be environmental friendly, considering that cells of Kluveromyces marxianus are readily available as wastes from food fermentation industries. Europium [152Eu+154Eu]-labelled solutions were used providing better accuracy and reproducibility of measurements, mainly in low concentration range. The effect of pH, contact time and europium initial concentration were investigated. Adsorption data were fitted to Langmuir and Freundlich sorption models and Scatchard plots were used to reveal the existence of at least two types of binding sites.

Study of poly(L-lactide) microparticles based on supercritical CO2.

PubMed

Chen, Ai-Zheng; Pu, Xi-Ming; Kang, Yun-Qing; Liao, Li; Yao, Ya-Dong; Yin, Guang-Fu

2007-12-01

Poly(L-lactide) (PLLA) microparticles were prepared in supercritical anti-solvent process. The effects of several key factors on surface morphology, and particle size and particle size distribution were investigated. These factors included initial drops size, saturation ratio of PLLA solution, pressure, temperature, concentration of the organic solution, the flow rate of the solution and molecular weight of PLLA. The results indicated that the saturation ratio of PLLA solution, concentration of the organic solution and flow rate of the solution played important roles on the properties of products. Various microparticles with the mean particle size ranging from 0.64 to 6.64 microm, could be prepared by adjusting the operational parameters. Fine microparticles were obtained in a process namely solution-enhanced dispersion by supercritical fluids (SEDS) process with dichloromethane/acetone mixture as solution.

Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for industrial and anthropogenic waste-indicator compounds in sediment

USGS Publications Warehouse

Burkhardt, M.R.; ReVello, R.C.; Smith, S.G.; Zaugg, S.D.

2005-01-01

A broad range of organic compounds is recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This method was developed to better determine the distribution of 61 compounds that are typically associated with industrial and household waste as well as some that are toxic and known (or suspected) for endocrine-disrupting potential extracted from environmental sediment samples. Pressurized liquid extraction (PLE) coupled with solid-phase extraction (SPE) was used to reduce sample preparation time, reduce solvent consumption to one-fifth of that required using dichloromethane-based Soxhlet extraction, and to minimize background interferences for full scan GC/MS analysis. Recoveries from spiked Ottawa sand, commercially available topsoil, and environmental stream sediment, fortified at 4-720 ??g per compound, averaged 76 ?? 13%. Initial method detection limits for single-component compounds ranged from 12.5 to 520 ??g/kg, based on 25 g samples. Results from 103 environmental sediment samples show that 36 out of 61 compounds (59%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, beta-sitosterol, a plant sterol, was detected in 87 of the 103 (84.5%) environmental samples with a concentration range 360-100,000 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction are also compared. ?? 2004 Published by Elsevier B.V.

Varying termiticide application rate and volume affect initial soil penetration

Treesearch

Christopher Peterson

2010-01-01

The initial soil penetration of Premise 75 and Termidor SC, containing imidacloprid and fipronil, respectively, were tested in laboratory columns of five different soils. Three combinations of application concentration and volume were used: double the recommended active ingredient concentration at one half the recommended volume (DR), the full concentration and volume...

Survey of minerals and fat-soluble vitamins in captive black and white ruffed lemurs (Varecia variegata).

PubMed

Crawford, Graham C; Puschner, Birgit; Dierenfeld, Ellen S; Dunker, Freeland

2009-12-01

Serum and whole blood samples from 64 clinically normal captive black and white ruffed lemurs (Varecia variegata), aged 6 mo to 32 yr, were analyzed to survey mineral and fat-soluble vitamin concentrations. All animals were fed a commercial primate food and a wide range of fruits and vegetables. Specific commercial diet information was available for 52 animals that were fed one of 10 different diets. Data analysis showed no differences in the analytes attributable to sex or access to natural ultraviolet light. Serum phosphorus (range: 1.4-3.1 mmol/L) was significantly higher and retinol (range: 0.38-1.23 micromol/L) was significantly lower in young animals (< or =4 yr). Iron (range: 17.2-77.0 micromol/L) and copper (range: 10.7-53.3 micromol/L) were much higher than concentrations reported in other free-ranging lemur species, and in some animals were at levels considered potentially toxic in domestic animals. Magnesium (range: 0.66-2.04 mmol/L), sodium (range: 111-201 mmol/L), and potassium (range: 2.0-6.8 mmol/L) ranged both lower and higher than concentrations considered adequate for a mammal, but were similar to concentrations reported in wild red ruffed lemurs (Varecia rubra), a closely related species. Selenium (range: 3.5-7.7 micromol/L) was within the range expected for a mammal, but higher than concentrations reported in wild V rubra. Zinc (range: 9.2-62.7 micromol/L) was similar to concentrations reported in V. rubra. Calcidiol (range: <12.5-144.8 nmol/L) and retinol (range: 0.38-2.95 micromol/L) were both lower and higher than concentrations reported in V. rubra. Lower serum calcidiol concentration correlated with lower commercial dietary vitamin D3. Alpha-tocopherol (range: 1.2-17.6 micromol/L) and y-tocopherol (range: 0.3-3.9 micromol/L) were within a range expected in a captive frugivorous primate but higher than concentrations found in wild V. rubra.

Power Scaling and Seasonal Evolution of Floe Areas in the Arctic East Siberian Sea

NASA Astrophysics Data System (ADS)

Barton, C. C.; Geise, G. R.; Tebbens, S. F.

2016-12-01

The size distribution of floes and its evolution during the Arctic summer season and a model of fragmentation that generates a power law scaling distribution of fragment sizes are the subject of this paper. This topic is of relevance to marine vessels that encounter floes, to the calculation of sea ice albedo, to the determination of Arctic heat exchange which is strongly influenced by ice concentrations and the amount of open water between floes, and to photosynthetic marine organisms which are dependent upon sunlight penetrating the spaces between floes. Floes are 2-3 m thick and initially range in area from one to millions of square meters. The cumulative number versus floe area distribution of seasonal sea floes from six satellite images of the Arctic Ocean during the summer breakup and melting is well fit by two scale-invariant power law scaling regimes for floe areas ranging from 30 m2 to 28,400,000 m2. Scaling exponents, B, for larger floe areas range from -0.6 to -1.0 with an average of -0.8. Scaling exponents, B, for smaller floe areas range from -0.3 to -0.6 with an average of -0.5. The inflection point between the two scaling regimes ranges from 283 x 102 m2 to 4850 x 102 m2 and generally moves from larger to smaller floe areas through the summer melting season. We observe that the two scaling regimes and the inflection between them are established during the initial breakup of sea ice solely by the process of fracture. The distributions of floe size regimes retain their scaling exponents as the floe pack evolves from larger to smaller floe areas from the initial breakup through the summer season, due to grinding, crushing, fracture, and melting. The scaling exponents for floe area distribution are in the same range as those reported in previous studies of Arctic floes and for the single scaling exponents found for crushed and ground geologic materials including streambed gravel, lunar debris, and artificially crushed quartz. A probabilistic fragmentation model that produces a power distribution of particle sizes has been developed and will be presented.

Coupling passive air sampling with emission estimates and chemical fate modeling for persistent organic pollutants (POPs): a feasibility study for Northern Europe.

PubMed

Gioia, Rosalinda; Sweetman, Andy J; Jones, Kevin C

2007-04-01

Passive air samplers (polyurethane foam disks) were deployed at 23 background locations along a broadly west-east transect in 8 northern European countries and analyzed for PCBs, PBDEs, PAHs, and a range of organochlorine pesticides (HCB, DDTs, and DDEs). PCBs and PAHs were highest at the center of the transect (Denmark) and lowest in northern Norway. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher DDE and DDT levels occurred in Eastern Europe and at several sites in Central Europe. PBDE levels were generally similar at all sites, but lower for some locations in Eastern Europe and Ireland. Emissions information for PCBs, HCB, and PBDEs was used as input for a multi-media chemical fate model, to generate predicted air concentrations and compare with these measured values. Different scenarios were highlighted by this exercise: (i) country and compound combinations where the national inventory gave predicted air concentrations in close agreement with those measured (e.g., PCBs in the UK); (ii) country and compound combinations where predicted concentrations were well below those measured, but where advection of emissions from elsewhere is likely to be important (e.g., PCBs in Norway); (iii) consistent underestimation of compound concentrations by the emissions modeling (i.e., HCB); and (iv) general overestimation of ambient concentrations (i.e., PBDEs). Air mass trajectory analysis showed the likely role of long-range atmospheric transport (LRAT) on national levels. In general, advection from the south and west of Europe appeared to contribute to ambient POPs levels for countries in the center and northeast of the transect. Guidelines are presented as to how countries that want to assess their POPs source inventories can do so with this relatively cheap initial screening approach.

Pharmacokinetics/pharmacodynamics of levofloxacin 750 mg once daily in young women with acute uncomplicated pyelonephritis.

PubMed

Nicolle, Lindsay; Duckworth, Heather; Sitar, Dan; Bryski, Lisa; Harding, Godfrey; Zhanel, George

2008-03-01

This pilot study was undertaken to characterise the pharmacokinetics, pharmacodynamics and potential clinical efficacy of levofloxacin 750 mg once daily for 5 days for treatment of women with acute uncomplicated pyelonephritis. Four women diagnosed with acute pyelonephritis were enrolled. Following pre-therapy specimen collection, an initial oral dose of 750 mg levofloxacin was administered. The mean pharmacokinetic parameters for the first dose were: maximum serum concentration (C(max)) 12.5+/-4.7 mg/L (range 5.6-16.0mg/L) (fC(max) 8.8+/-3.3, where f indicates the levofloxacin free or non-protein-bound fraction), area under the serum concentration-time curve (AUC) 85.4+/-14.1 mgh/L (range 66.2-96.8 mgh/L) (fAUC 59.8+/-9.9) and serum half-life (t(1/2)) 6.7+/-0.5h. Mean urine concentrations were 88.0+/-100mg/L at the 0-3 h collection, 307+/-143 mg/L at 3-6 h, 170+/-107 mg/L at 6-12 h and 85+/-8 mg/L at 12-24 h. Mean levofloxacin serum pharmacodynamics for infecting Escherichia coli were: C(max)/minimum inhibitory concentration (MIC) 323+/-185(fC(max)/MIC 226+/-129); and AUC/MIC 2339+/-830(fAUC/MIC 1647+/-579). Mean urine levofloxacin concentration/MIC ratios were: 900+/-1389 for 0-3 h, 12100+/-4950 for 3-6 h, 5922+/-3912 for 6-12 h and 2233+/-1037 for 12-24 h. Levofloxacin eradicated E. coli from the urine by 3-6 h after the first dose. Levofloxacin 750 mg once daily for 5 days has pharmacodynamics that support further evaluation of this regimen for treatment of women with acute uncomplicated pyelonephritis.

Transfer Behavior of the Weakly Acidic BCS Class II Drug Valsartan from the Stomach to the Small Intestine During Fasted and Fed States.

PubMed

Hamed, Rania; Alnadi, Sabreen Hasan

2018-05-07

The objective of this study was to investigate the transfer behavior of the weakly acidic BCS class II drug valsartan from the stomach to the small intestine during fasted and fed states. An in vitro transfer model previously introduced by Kostewicz et al. (J Pharm Pharmacol 56(1):43-51, 2004) based on a syringe pump and a USP paddle apparatus was used to determine the concentration profiles of valsartan in the small intestine. Donor phases of simulated gastric fluid during fasted (FaSSGF) and fed (FeSSGF) states were used to predisperse Diovan® tablets (160 mg valsartan). The initial concentrations of valsartan in FaSSGF and FeSSGF were 6.2 and 91.8%, respectively. Valsartan dispersions were then transferred to acceptor phases that simulate intestinal fluid and cover the physiological properties (pH, buffer capacity, and ionic strength) of the gastrointestinal fluid at a flow rate of 2 mL/min. The pH measurements were reported at time intervals corresponded to those of the transfer experiments to investigate the effect of percent dissolved of valsartan in the donor phase on lowering the pH of the acceptor phases. The f2 similarity test was used to compare the concentration profiles in the acceptor phases. In fasted state, the concentration of valsartan in the acceptor phases ranged between 33.1 and 89.4% after 240 min. Whereas in fed state, valsartan was fully dissolved in all acceptor phases within a range of 94.5-104.9% after 240 min. Therefore, the transfer model provides a useful screen for the concentrations of valsartan in the small intestine during fasted and fed states.

Attenuation of Congenital Portosystemic Shunt Reduces Inflammation in Dogs

PubMed Central

Tivers, Michael S.; Handel, Ian; Gow, Adam G.; Lipscomb, Victoria J.; Jalan, Rajiv; Mellanby, Richard J.

2015-01-01

Liver disease is a major cause of morbidity and mortality. One of the most significant complications in patients with liver disease is the development of neurological disturbances, termed hepatic encephalopathy. The pathogenesis of hepatic encephalopathy is incompletely understood, which has resulted in the development of a wide range of experimental models. Congenital portosystemic shunt is one of the most common congenital disorders diagnosed in client owned dogs. Our recent studies have demonstrated that the pathophysiology of canine hepatic encephalopathy is very similar to human hepatic encephalopathy, which provides strong support for the use of dogs with a congenital portosystemic shunt as a naturally occurring model of human hepatic encephalopathy. Specifically, we have demonstrated an important role for ammonia and inflammation in the development of hepatic encephalopathy in dogs with a congenital portosystemic shunt. Despite the apparent importance of inflammation in driving hepatic encephalopathy in dogs, it is unclear whether inflammation resolves following the successful treatment of liver disease. We hypothesized that haematological and biochemical evidence of inflammation, as gauged by neutrophil, lymphocyte and monocyte concentrations together with C-reactive protein concentrations, would decrease following successful treatment of congenital portosystemic shunts in dogs. One hundred and forty dogs with a congenital portosystemic shunt were enrolled into the study. We found that the proportion of dogs with a monocyte concentration above the reference range was significantly greater in dogs with hepatic encephalopathy at time of initial diagnosis. Importantly, neutrophil and monocyte concentrations significantly decreased following surgical congenital portosystemic shunt attenuation. We also found a significant decrease in C-reactive protein concentrations following surgical attenuation of congenital portosystemic shunts. Our study demonstrates that haematological and biochemical indices of inflammation reduce following successful treatment of the underlying liver disorder. PMID:25658922

Functionality based detection of airborne engineered nanoparticles in quasi real time: a new type of detector and a new metric.

PubMed

Neubauer, Nicole; Seipenbusch, Martin; Kasper, Gerhard

2013-08-01

A new type of detector which we call the Catalytic Activity Aerosol Monitor (CAAM) was investigated towards its capability to detect traces of commonly used industrial catalysts in ambient air in quasi real time. Its metric is defined as the catalytic activity concentration (CAC) expressed per volume of sampled workplace air. We thus propose a new metric which expresses the presence of nanoparticles in terms of their functionality - in this case a functionality of potential relevance for damaging effects - rather than their number, surface, or mass concentration in workplace air. The CAAM samples a few micrograms of known or anticipated airborne catalyst material onto a filter first and then initiates a chemical reaction which is specific to that catalyst. The concentration of specific gases is recorded using an IR sensor, thereby giving the desired catalytic activity. Due to a miniaturization effort, the laboratory prototype is compact and portable. Sensitivity and linearity of the CAAM response were investigated with catalytically active palladium and nickel nano-aerosols of known mass concentration and precisely adjustable primary particle size in the range of 3-30 nm. With the miniature IR sensor, the smallest detectable particle mass was found to be in the range of a few micrograms, giving estimated sampling times on the order of minutes for workplace aerosol concentrations typically reported in the literature. Tests were also performed in the presence of inert background aerosols of SiO2, TiO2, and Al2O3. It was found that the active material is detectable via its catalytic activity even when the particles are attached to a non-active background aerosol.

Effects of limonene on ruminal concentrations, fermentation, and lysine degradation in cattle.

PubMed

Samii, S Saed; Wallace, N; Nagaraja, T G; Engstrom, M A; Miesner, M D; Armendariz, C K; Titgemeyer, E C

2016-08-01

Previous in vitro data showed that was inhibited by limonene. We further evaluated effects of limonene on growth of in vitro as well as on ruminal concentrations of in vivo. With in vitro cultivation in anaerobic brain-heart infusion broth, limonene decreased growth of . Thymol also reduced growth of , but it was less effective than limonene. Tylosin effectively reduced growth of in vitro. Although the response over fermentation times and concentrations of antimicrobials differed somewhat between tylosin and limonene, the 2 antimicrobial agents yielded similar inhibitory effects on growth of at concentrations ranging from 6 to 24 mg/L. The effects of limonene on ruminal concentration in vivo were tested in 7 ruminally cannulated heifers (225 kg initial BW) used in a 7 × 4 Youden square design. Treatments included: 1) control, 2) limonene at 10 mg/kg diet DM, 3) limonene at 20 mg/kg diet DM, 4) limonene at 40 mg/kg diet DM, 5) limonene at 80 mg/kg diet DM, 6) CRINA-L (a blend of essential oil components) at 180 mg/kg diet DM, and 7) tylosin at 12 mg/kg diet DM. Each period included 11 d with 10 d washouts between periods. Samples of ruminal contents were collected before treatment initiation and after 4, 7, and 10 d of treatment for measuring by the most probable number method using selective culture medium. Limonene linearly decreased ( = 0.03) ruminal concentration, with the lowest concentration achieved with 40 mg of limonene/kg dietary DM. Limonene tended ( ≤ 0.07) to linearly reduce ruminal molar proportions of propionate and valerate while tending to linearly increase ( ≤ 0.10) those of butyrate and 2-methyl butyrate. Limonene did not affect ruminal NH concentrations or degradation rates of lysine. Neither CRINA-L ( = 0.52) nor tylosin ( = 0.19) affected ruminal concentrations. CRINA-L significantly decreased ruminal concentrations of NH and molar proportions of 3-methyl butyrate, whereas tylosin significantly decreased molar proportions of propionate while increasing those of butyrate and tending to increase those of acetate. Limonene supplementation reduced ruminal concentrations of suggesting that it may have the potential to reduce the prevalence of liver abscesses, although further research is needed to assess the effect of limonene in feedlot cattle.

Use of drinking water treatment solids for arsenate removal from desalination concentrate.

PubMed

Xu, Xuesong; Lin, Lu; Papelis, Charalambos; Myint, Maung; Cath, Tzahi Y; Xu, Pei

2015-05-01

Desalination of impaired water can be hindered by the limited options for concentrate disposal. Selective removal of specific contaminants using inexpensive adsorbents is an attractive option to address the challenges of concentrate management. In this study, two types of ferric-based drinking water treatment solids (DWTS) were examined for arsenate removal from reverse osmosis concentrate during continuous-flow once-through column experiments. Arsenate sorption was investigated under different operating conditions including pH, arsenate concentration, hydraulic retention time, loading rate, temperature, and moisture content of the DWTS. Arsenate removal by the DWTS was affected primarily by surface complexation, electrostatic interactions, and arsenate speciation. Results indicated that arsenate sorption was highly dependent on initial pH and initial arsenate concentration. Acidic conditions enhanced arsenate sorption as a result of weaker electrostatic repulsion between predominantly monovalent H2AsO4(-) and negatively charged particles in the DWTS. High initial arsenate concentration increased the driving force for arsenate sorption to the DWTS surface. Tests revealed that the potential risks associated with the use of DWTS include the leaching of organic contaminants and ammonia, which can be alleviated by using wet DWTS or discarding the initially treated effluent that contains high organic concentration. Copyright © 2015 Elsevier Inc. All rights reserved.

Screening and evaluation of polymers as flocculation aids for the treatment of aquacultural effluents

USGS Publications Warehouse

Ebeling, J.M.; Rishel, K.L.; Sibrell, P.L.

2005-01-01

As environmental regulations become more stringent, environmentally sound waste management and disposal are becoming increasingly more important in all aquaculture operations. One of the primary water quality parameters of concern is the suspended solids concentration in the discharged effluent. For example, EPA initially considered the establishment of numerical limitations for only one single pollutant: total suspended solids (TSS). For recirculation systems, the proposed TSS limitations would have applied to solids polishing or secondary solids removal technology. The new rules and regulations from EPA (August 23, 2004) require only qualitative TSS limits, in the form of solids control best management practices (BMP), allowing individual regional and site specific conditions to be addressed by existing state or regional programs through NPDES permits. In recirculation systems, microscreen filters are commonly used to remove the suspended solids from the process water. Further concentration of suspended solids from the backwash water of the microscreen filter could significantly reduce quantity of discharge water. And in some cases, the backwash water from microscreen filters needs to be further concentrated to minimize storage volume during over wintering for land disposal or other final disposal options. In addition, this may be required to meet local, state, and regional discharge water quality. The objective of this research was an initial screening of several commercially available polymers routinely used as coagulation-flocculation aids in the drinking and wastewater treatment industry and determination of their effectiveness for the treatment of aquaculture wastewater. Based on the results of the initial screening, a further evaluation of six polymers was conducted to estimate the optimum polymer dosage for flocculation of aquaculture microscreen effluent and overall solids removal efficiency. Results of these evaluations show TSS removal was close to 99% via settling, with final TSS values ranging from as low as 10-17 mg/L. Although not intended to be used for reactive phosphorus (RP) removal, RP was reduced by 92-95% by removing most of the TSS in the wastewater to approximately 1 mg/L-P. Dosage requirements were fairly uniform, requiring between 15 and 20 mg/L of polymer. Using these dosages, estimated costs range from $4.38 to $13.08 per metric tonne of feed. ?? 2005 Elsevier B.V. All rights reserved.

Variable frequency iteration MPPT for resonant power converters

DOEpatents

Zhang, Qian; Bataresh, Issa; Chen, Lin

2015-06-30

A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values.

Sodium Sulfate Separation from Aqueous Alkaline Solutions via Crystalline Urea-Functionalized Capsules: Thermodynamics and Kinetics of Crystallization

DOE PAGES

Custelcean, Radu; Sloop, Frederick V.; Rajbanshi, Arbin; ...

2014-12-04

We measured the thermodynamics and kinetics of crystallization of sodium sulfate with a tripodal tris-urea receptor (L1) from aqueous alkaline solutions in the 15 55 C temperature range, with the goal of identifying the optimal conditions for efficient and quick sulfate removal from nuclear wastes. The use of radiolabeled Na 2 35SO 4 provided a practical way to monitor the sulfate concentration in solution by liquid scintillation counting. Our results are consistent with a two-step crystallization mechanism, involving relatively quick dissolution of crystalline L1 followed by the rate-limiting crystallization of the Na 2SO 4(L1) 2(H 2O) 4 capsules. We foundmore » that temperature exerted relatively little influence over the equilibrium sulfate concentration, which ranged between 0.004 and 0.011 M. Moreover, this corresponds to 77 91% removal of sulfate from a solution containing 0.0475 M initial sulfate concentration, as found in a typical Hanford waste tank. The apparent pseudo-first-order rate constant for sulfate removal increased 20-fold from 15 to 55 C, corresponding to an activation energy of 14.1 kcal/mol. At the highest measured temperature of 55 C, 63% and 75% of sulfate was removed from solution within 8 h and 24 h, respectively.« less

Effects of temperature and glycerol and methanol-feeding profiles on the production of recombinant galactose oxidase in Pichia pastoris

PubMed Central

Anasontzis, George E; Salazar Penã, Margarita; Spadiut, Oliver; Brumer, Harry; Olsson, Lisbeth

2014-01-01

Optimization of protein production from methanol-induced Pichia pastoris cultures is necessary to ensure high productivity rates and high yields of recombinant proteins. We investigated the effects of temperature and different linear or exponential methanol-feeding rates on the production of recombinant Fusarium graminearum galactose oxidase (EC 1.1.3.9) in a P. pastoris Mut+ strain, under regulation of the AOX1 promoter. We found that low exponential methanol feeding led to 1.5-fold higher volumetric productivity compared to high exponential feeding rates. The duration of glycerol feeding did not affect the subsequent product yield, but longer glycerol feeding led to higher initial biomass concentration, which would reduce the oxygen demand and generate less heat during induction. A linear and a low exponential feeding profile led to productivities in the same range, but the latter was characterized by intense fluctuations in the titers of galactose oxidase and total protein. An exponential feeding profile that has been adapted to the apparent biomass concentration results in more stable cultures, but the concentration of recombinant protein is in the same range as when constant methanol feeding is employed. © 2014 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 30:728–735, 2014 PMID:24493559

Methamphetamine blood concentrations in human abusers: application to pharmacokinetic modeling.

PubMed

Melega, William P; Cho, Arthur K; Harvey, Dennis; Laćan, Goran

2007-04-01

Characterization of methamphetamine's (METH) dose-dependent effects on brain neurochemistry may represent a critical component for better understanding the range of resultant behavioral pathologies. Most human studies, however, have assessed only the effects of long term, high dose METH abuse (e.g., greater than 1000 mg/day) in individuals meeting DSM-IV criteria for METH dependence. Yet, for the majority of METH abusers, their patterns of METH exposure that consist of lower doses remain less well-characterized. In this study, blood samples were obtained from 105 individuals detained by police for possible criminal activity and testing positive for stimulants by EMIT assay. METH blood concentrations were subsequently quantified by GC-MS and were predominantly in the low micromolar range (0.1-11.1 microM), with median and mean values of 1.3 microM (0.19 mg/l) and 2 microM (0.3 mg/l), respectively. Pharmacokinetic calculations based on these measured values were used to estimate initial METH body burdens, the median value being 52 mg. Modeling a 52 mg dose for a 4 day-METH maintenance exposure pattern of 4 doses/day at 4 h intervals showed that blood concentrations remained between 1 and 4 microM during this period. Collectively, these data present evidence for a METH exposure pattern distinct from high dose-METH abuse and provide the rationale for assessing potential brain pathology associated with such lower dose-METH exposure.

Biphasic Elimination of Tenofovir Diphosphate and Nonlinear Pharmacokinetics of Zidovudine Triphosphate in a Microdosing Study

PubMed Central

Chen, Jianmeng; Flexner, Charles; Liberman, Rosa G.; Skipper, Paul L.; Louissaint, Nicolette; Tannenbaum, Steven R.; Hendrix, Craig; Fuchs, Edward

2012-01-01

Objective Phase 0 studies can provide initial pharmacokinetics (PK) data in humans and help to facilitate early drug development, but their predictive value for standard dosing is controversial. To evaluate the prediction of microdosing for active intracellular drug metabolites, we compared the PK profile of two antiretroviral drugs, zidovudine (ZDV) and tenofovir (TFV), in microdose and standard dosing regimens. Study Design We administered a microdose (100 μg) of 14C-labeled drug (ZDV or tenofovir disoproxil fumarate (TDF)) with or without a standard unlabelled dose (300 mg) to healthy volunteers. Both the parent drug in plasma and the active metabolite, ZDV-triphosphate (ZDV-TP) or TFV-diphosphate (TFV-DP) in PBMCs and CD4+ cells were measured by AMS. Results The intracellular ZDV-TP concentration increased less than proportionally over the dose range studied (100 μg to 300 mg), while the intracellular TFV-DP PK were linear over the same dose range. ZDV-TP concentrations were lower in CD4+ cells versus total peripheral blood mononuclear cells (PBMCs), while TFV-DP concentrations were not different in CD4+ cells and PBMCs. Conclusion Our data were consistent with a rate-limiting step in the intracellular phosphorylation of ZDV but not TFV. AMS shows promise for predicting the PK of active intracellular metabolites of nucleosides, but nonlinearity of PK may be seen with some drugs. PMID:23187888

Experimental co-digestion of corn stalk and vermicompost to improve biogas production

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

Chen Guangyin; Zheng Zheng, E-mail: zzhenghj@fudan.edu.c; Department of Environmental Science and Engineering, Fudan University, Shanghai 200433

2010-10-15

Anaerobic co-digestion of corn stalk and vermicompost (VC) as well as mono-digestion of corn stalk were investigated. Batch mono-digestion experiments were performed at 35 {+-} 1 {sup o}C and initial total solid loading (TSL) ranged from 1.2% to 6.0%. Batch co-digestion experiments were performed at 35 {+-} 1 {sup o}C and initial TSL of 6% with VC proportions ranged from 20% to 80% of total solid (TS). For mono-digestion of corn stalk, a maximum methane yield of 217.60 {+-} 13.87 mL/g TS{sub added} was obtained at initial TSL of 4.8%, and acidification was found at initial TSL of 6.0% withmore » the lowest pH value of 5.10 on day 4. Co-digestion improved the methane yields by 4.42-58.61% via enhancing volatile fatty acids (VFAs) concentration and pH value compared with mono-digestion of corn stalk. The maximum biogas yield of 410.30 {+-} 11.01 mL/g TS{sub added} and methane yield of 259.35 {+-} 13.85 mL/g TS{sub added} were obtained for 40% VC addition. Structure analysis by X-ray diffractometry (XRD) showed that the lowest crystallinity of 35.04 of digested corn stalk was obtained from co-digestion with 40% VC, which decreased 29.4% compared to 49.6 obtained from un-treated corn stalk. It is concluded that co-digestion with VC is beneficial for improving biodigestibility and methane yield from corn stalk.« less

Inverse modelling-based reconstruction of the Chernobyl source term available for long-range transport

NASA Astrophysics Data System (ADS)

Davoine, X.; Bocquet, M.

2007-03-01

The reconstruction of the Chernobyl accident source term has been previously carried out using core inventories, but also back and forth confrontations between model simulations and activity concentration or deposited activity measurements. The approach presented in this paper is based on inverse modelling techniques. It relies both on the activity concentration measurements and on the adjoint of a chemistry-transport model. The location of the release is assumed to be known, and one is looking for a source term available for long-range transport that depends both on time and altitude. The method relies on the maximum entropy on the mean principle and exploits source positivity. The inversion results are mainly sensitive to two tuning parameters, a mass scale and the scale of the prior errors in the inversion. To overcome this hardship, we resort to the statistical L-curve method to estimate balanced values for these two parameters. Once this is done, many of the retrieved features of the source are robust within a reasonable range of parameter values. Our results favour the acknowledged three-step scenario, with a strong initial release (26 to 27 April), followed by a weak emission period of four days (28 April-1 May) and again a release, longer but less intense than the initial one (2 May-6 May). The retrieved quantities of iodine-131, caesium-134 and caesium-137 that have been released are in good agreement with the latest reported estimations. Yet, a stronger apportionment of the total released activity is ascribed to the first period and less to the third one. Finer chronological details are obtained, such as a sequence of eruptive episodes in the first two days, likely related to the modulation of the boundary layer diurnal cycle. In addition, the first two-day release surges are found to have effectively reached an altitude up to the top of the domain (5000 m).

Quinine Pharmacokinetics and Pharmacodynamics in Children with Malaria Caused by Plasmodium falciparum

PubMed Central

Le Jouan, M.; Jullien, V.; Tetanye, E.; Tran, A.; Rey, E.; Tréluyer, J.-M.; Tod, M.; Pons, G.

2005-01-01

The aim of the present study was to assess the pharmacokinetics and the efficacy of a shorter than usual 5-day quinine treatment given orally to children in Cameroon with malaria caused by Plasmodium falciparum. Quinine (8.3 mg of base per kg of body weight every 8 h) was administered as a 2% formiate salt syrup for 5 days to 30 children (age range, 0.55 to 6.7 years) with uncomplicated falciparum malaria (initial parasitemia, 1.4 × 103 to 1.8 × 105/μl). Quinine concentrations in plasma samples (five to nine per patient) were measured by liquid chromatography on days 1 to 3. Parasitemia was counted on days 0, 1, 2, 3, 4, 7, and 14. Pharmacokinetic and pharmacodynamic data were analyzed by population approaches by using NONMEM and WinBugs, respectively. The kinetics of quinine were best described by a one-compartment model with time-varying protein binding. Clearance and the volume of distribution were positively correlated with body weight and increased over time. Parasitemia was undetectable from day 3 to 14 in all children. The time to a 4-log reduction of the initial level of parasitemia (Ter) was related to the average quinine concentration from 0 to 72 h (Cav) as Ter = Tmin [1 + (C50/Cav)s], where sigmoidicity (s) is equal to 2, Tmin is the time to eradication at infinite Cav, and C50 is the value of Cav for which Ter is twice Tmin. The C50 distribution was unimodal, and all C50 values were less than 8 mg/liter, while Cav ranged from 5.9 to 18.3 mg/liter. The median (10th to 90th percentile) Ter was 47 h (range, 39 to 76 h). The efficacy of a 5-day treatment course should be evaluated in a larger clinical trial. PMID:16127036

An initial investigation of multidimensional flow and transverse mixing characteristics of the Ohio River near Cincinnati, Ohio

USGS Publications Warehouse

Holtschlag, David J.

2009-01-01

Two-dimensional hydrodynamic and transport models were applied to a 34-mile reach of the Ohio River from Cincinnati, Ohio, upstream to Meldahl Dam near Neville, Ohio. The hydrodynamic model was based on the generalized finite-element hydrodynamic code RMA2 to simulate depth-averaged velocities and flow depths. The generalized water-quality transport code RMA4 was applied to simulate the transport of vertically mixed, water-soluble constituents that have a density similar to that of water. Boundary conditions for hydrodynamic simulations included water levels at the U.S. Geological Survey water-level gaging station near Cincinnati, Ohio, and flow estimates based on a gate rating at Meldahl Dam. Flows estimated on the basis of the gate rating were adjusted with limited flow-measurement data to more nearly reflect current conditions. An initial calibration of the hydrodynamic model was based on data from acoustic Doppler current profiler surveys and water-level information. These data provided flows, horizontal water velocities, water levels, and flow depths needed to estimate hydrodynamic parameters related to channel resistance to flow and eddy viscosity. Similarly, dye concentration measurements from two dye-injection sites on each side of the river were used to develop initial estimates of transport parameters describing mixing and dye-decay characteristics needed for the transport model. A nonlinear regression-based approach was used to estimate parameters in the hydrodynamic and transport models. Parameters describing channel resistance to flow (Manning’s “n”) were estimated in areas of deep and shallow flows as 0.0234, and 0.0275, respectively. The estimated RMA2 Peclet number, which is used to dynamically compute eddy-viscosity coefficients, was 38.3, which is in the range of 15 to 40 that is typically considered appropriate. Resulting hydrodynamic simulations explained 98.8 percent of the variability in depth-averaged flows, 90.0 percent of the variability in water levels, 93.5 percent of the variability in flow depths, and 92.5 percent of the variability in velocities. Estimates of the water-quality-transport-model parameters describing turbulent mixing characteristics converged to different values for the two dye-injection reaches. For the Big Indian Creek dye-injection study, an RMA4 Peclet number of 37.2 was estimated, which was within the recommended range of 15 to 40, and similar to the RMA2 Peclet number. The estimated dye-decay coefficient was 0.323. Simulated dye concentrations explained 90.2 percent of the variations in measured dye concentrations for the Big Indian Creek injection study. For the dye-injection reach starting downstream from Twelvemile Creek, however, an RMA4 Peclet number of 173 was estimated, which is far outside the recommended range. Simulated dye concentrations were similar to measured concentration distributions at the first four transects downstream from the dye-injection site that were considered vertically mixed. Farther downstream, however, simulated concentrations did not match the attenuation of maximum concentrations or cross-channel transport of dye that were measured. The difficulty of determining a consistent RMA4 Peclet was related to the two-dimension model assumption that velocity distributions are closely approximated by their depth-averaged values. Analysis of velocity data showed significant variations in velocity direction with depth in channel reaches with curvature. Channel irregularities (including curvatures, depth irregularities, and shoreline variations) apparently produce transverse currents that affect the distribution of constituents, but are not fully accounted for in a two-dimensional model. The two-dimensional flow model, using channel resistance to flow parameters of 0.0234 and 0.0275 for deep and shallow areas, respectively, and an RMA2 Peclet number of 38.3, and the RMA4 transport model with a Peclet number of 37.2, may have utility for emergency-planning purposes. Emergency-response efforts would be enhanced by continuous streamgaging records downstream from Meldahl Dam, real-time water-quality monitoring, and three-dimensional modeling. Decay coefficients are constituent specific.

Investigation of particle inertial migration in high particle concentration suspension flow by multi-electrodes sensing and Eulerian-Lagrangian simulation in a square microchannel

PubMed Central

Zhao, Tong; Liu, Kai; Takei, Masahiro

2016-01-01

The inertial migration of neutrally buoyant spherical particles in high particle concentration (αpi > 3%) suspension flow in a square microchannel was investigated by means of the multi-electrodes sensing method which broke through the limitation of conventional optical measurement techniques in the high particle concentration suspensions due to interference from the large particle numbers. Based on the measured particle concentrations near the wall and at the corner of the square microchannel, particle cross-sectional migration ratios are calculated to quantitatively estimate the migration degree. As a result, particle migration to four stable equilibrium positions near the centre of each face of the square microchannel is found only in the cases of low initial particle concentration up to 5.0 v/v%, while the migration phenomenon becomes partial as the initial particle concentration achieves 10.0 v/v% and disappears in the cases of the initial particle concentration αpi ≥ 15%. In order to clarify the influential mechanism of particle-particle interaction on particle migration, an Eulerian-Lagrangian numerical model was proposed by employing the Lennard-Jones potential as the inter-particle potential, while the inertial lift coefficient is calculated by a pre-processed semi-analytical simulation. Moreover, based on the experimental and simulation results, a dimensionless number named migration index was proposed to evaluate the influence of the initial particle concentration on the particle migration phenomenon. The migration index less than 0.1 is found to denote obvious particle inertial migration, while a larger migration index denotes the absence of it. This index is helpful for estimation of the maximum initial particle concentration for the design of inertial microfluidic devices. PMID:27158288

Actinobacteria consortium as an efficient biotechnological tool for mixed polluted soil reclamation: Experimental factorial design for bioremediation process optimization.

PubMed

Aparicio, Juan Daniel; Raimondo, Enzo Emanuel; Gil, Raúl Andrés; Benimeli, Claudia Susana; Polti, Marta Alejandra

2018-01-15

The objective of the present work was to establish optimal biological and physicochemical parameters in order to remove simultaneously lindane and Cr(VI) at high and/or low pollutants concentrations from the soil by an actinobacteria consortium formed by Streptomyces sp. M7, MC1, A5, and Amycolatopsis tucumanensis AB0. Also, the final aim was to treat real soils contaminated with Cr(VI) and/or lindane from the Northwest of Argentina employing the optimal biological and physicochemical conditions. In this sense, after determining the optimal inoculum concentration (2gkg -1 ), an experimental design model with four factors (temperature, moisture, initial concentration of Cr(VI) and lindane) was employed for predicting the system behavior during bioremediation process. According to response optimizer, the optimal moisture level was 30% for all bioremediation processes. However, the optimal temperature was different for each situation: for low initial concentrations of both pollutants, the optimal temperature was 25°C; for low initial concentrations of Cr(VI) and high initial concentrations of lindane, the optimal temperature was 30°C; and for high initial concentrations of Cr(VI), the optimal temperature was 35°C. In order to confirm the model adequacy and the validity of the optimization procedure, experiments were performed in six real contaminated soils samples. The defined actinobacteria consortium reduced the contaminants concentrations in five of the six samples, by working at laboratory scale and employing the optimal conditions obtained through the factorial design. Copyright © 2017 Elsevier B.V. All rights reserved.

49 CFR 40.95 - What are the adulterant cutoff concentrations for initial and confirmation tests?

Code of Federal Regulations, 2012 CFR

2012-10-01

... Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing... laboratory, you must use the cutoff concentrations for the initial and confirmation adulterant testing as...

49 CFR 40.95 - What are the adulterant cutoff concentrations for initial and confirmation tests?

Code of Federal Regulations, 2011 CFR

2011-10-01

... Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing... laboratory, you must use the cutoff concentrations for the initial and confirmation adulterant testing as...

49 CFR 40.95 - What are the adulterant cutoff concentrations for initial and confirmation tests?

Code of Federal Regulations, 2013 CFR

2013-10-01

... Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing... laboratory, you must use the cutoff concentrations for the initial and confirmation adulterant testing as...

49 CFR 40.95 - What are the adulterant cutoff concentrations for initial and confirmation tests?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing... laboratory, you must use the cutoff concentrations for the initial and confirmation adulterant testing as...

49 CFR 40.95 - What are the adulterant cutoff concentrations for initial and confirmation tests?

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing... laboratory, you must use the cutoff concentrations for the initial and confirmation adulterant testing as...

Postanesthetic recumbency associated with hyperkalemic periodic paralysis in a quarter horse.

PubMed

Robertson, S A; Green, S L; Carter, S W; Bolon, B N; Brown, M P; Shields, R P

1992-10-15

Anesthesia and surgery in a Quarter Horse affected with hyperkalemic periodic paralysis resulted in euthanasia after 7 days of postoperative recumbency. Initial recovery was uneventful after extensive sinus surgery, but within 2 hours, the horse had severe muscle weakness. Plasma electrolyte concentrations were within the normal range during the period of recumbency. There was no clinical or laboratory evidence of severe muscle damage. Despite treatment with acetazolamide, isoproterenol, and intensive nursing, the horse was unable to stand for more than a few seconds and developed severe decubital ulcers. Ultrastructural examination revealed nemaline rods and swollen mitochondria in disrupted myofibers.

Intra-arterial bolus of 125I labeled meglumine diatrizoate. Early extravascular distribution.

PubMed

Dean, P B; Kormano, M

1977-07-01

A mixture of 125I labeled meglumine diatrizoate and 131I labeled human serum albumin was injected into the lower abdominal aorta of 30 anesthetized, laparotomized male rats. Measurements of the activities in cardiac blood and in different tissues of the hindlimbs and tests were perfomed at six time intervals ranging from 5 seconds to 2 minutes after injection, the determine early uptake and distribution volumes of diatrizoate. Concentrations and distribution volumes were initially much greater than values obtained after intravenous injection, but these differences had considerably decreased or disappeared by 2 minutes.

Hydrogen separation membrane on a porous substrate

DOEpatents

Song, Sun-Ju [Orland Park, IL; Lee, Tae H [Naperville, IL; Chen, Ling [Woodridge, IL; Dorris, Stephen E [LaGrange Park, IL; Balachandran, Uthamalingam [Hinsdale, IL

2011-06-14

A hydrogen permeable membrane is disclosed. The membrane is prepared by forming a mixture of metal oxide powder and ceramic oxide powder and a pore former into an article. The article is dried at elevated temperatures and then sintered in a reducing atmosphere to provide a dense hydrogen permeable portion near the surface of the sintered mixture. The dense hydrogen permeable portion has a higher initial concentration of metal than the remainder of the sintered mixture and is present in the range of from about 20 to about 80 percent by volume of the dense hydrogen permeable portion.

Intense generation of respirable metal nanoparticles from a low-power soldering unit.

PubMed

Gómez, Virginia; Irusta, Silvia; Balas, Francisco; Santamaria, Jesus

2013-07-15

Evidence of intense nanoparticle generation from a low power (45W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10(6) particles/cm(3)) within the breathing range of the operator, with initial size distributions centered at 35-60nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals. Copyright © 2013 Elsevier B.V. All rights reserved.

Photocatalytic removal of doxycycline from aqueous solution using ZnO nano-particles: a comparison between UV-C and visible light.

PubMed

Pourmoslemi, Shabnam; Mohammadi, Ali; Kobarfard, Farzad; Amini, Mohsen

2016-10-01

Zinc oxide nano-particles were synthesized, characterized and used for photocatalytic degradation of doxycycline using UV-C and visible light. Effects of several operational factors including initial pH of antibiotic solution, initial antibiotic concentration and ZnO nano-particles loading amount were investigated. Comparing photocatalytic degradation and mineralization of doxycycline under UV-C and visible light showed successful application of the method under both light sources. However, reaction rate was higher under UV-C irradiation, which degraded doxycycline almost completely in 5 hours, and 68% mineralization was achieved. Synthesized ZnO nano-particles were successfully applied for photocatalytic degradation of doxycycline in a pharmaceutical wastewater sample. The process was fitted to the pseudo first order kinetic model with rate constants in the range of 6-22(×10 -3 ) mg L -1 min -1 with respect to initial concentration of doxycycline under UV-C irradiation. The Langmuir-Hinshelwood model was also employed for describing the photocatalytic reaction with surface reaction kinetic constant k c and equilibrium adsorption constant K LH values calculated as 0.12 mg L -1 min -1 and 2.2 L mg -1 , respectively. Degradation of doxycycline was followed by UV-visible spectroscopy and a validated stability indicating high-performance liquid chromatography method that was developed using stressed samples of doxycycline and could selectively determine doxycycline in the presence of its degradation products. Mass spectrometry was used for determining final degradation products.

Muscle paralyzing effect of the juice from the trunk of the banana tree.

PubMed

Singh, Y N; Dryden, W F

1985-01-01

The effect of an extract from the trunk of the banana tree (Musa sapientum) was investigated in isolated skeletal muscle preparations from the chick, mouse and frog using twitch tension and intracellular recording techniques. The extract produced, in the same concentration range and after an initial period of twitch augmentation, paralysis of skeletal muscle in both directly and indirectly stimulated preparations. It also had a dose-dependent stimulant effect on the muscle causing a contracture. The neuromuscular blockade was reversed by calcium, but only when added before complete paralysis of the muscle. On the other hand, neostigmine usually hastened the blockade and aggravated the contracture. The frequency of the miniature endplate potential in the mouse phrenic nerve-diaphragm preparation greatly increased initially, declining to an elevated plateau. Effects on quantal content of endplate potentials (e.p.p.s) were studied in the transected mouse phrenic nerve-hemidiaphragm using trains of e.p.p.s. In the presence of the extract, only a few e.p.p. trains could normally be evoked, probably due to nerve terminal block. When quantal content could be measured at low concentrations of the extract, an increase was usually obtained. Muscle action potentials in the frog sartorius muscle were decreased in amplitude until no further potentials could be generated. The results suggest that the nature of the block produced by the extract resembles that of a potent local anaesthetic with an initial atypical labilizing effect on cell calcium rather than a conventional curariform block.

Impact of asthma, exposure period, and filters on human responses during exposures to ozone and its initiated chemistry products.

PubMed

Fadeyi, M O; Tham, K W; Wu, W Y

2015-10-01

The impact of asthma, exposure period, and filter condition downstream of the mixing box of air-conditioning system on building occupants' perceptual response, work performance, and salivary α-amylase secretion during exposures to ozone and its initiated chemistry products is studied. The experiments were conducted in a field environmental chamber (FEC) (240 m(3)) simulating an office environment. Experiments were conducted during periods when the air-handling system operated with new or used pleated panel filters at constant recirculation (7/h) and ventilation (1/h) rates. Average ozone and secondary organic aerosols (ozone-initiated chemistry products) measured during non-asthmatic and asthmatic subjects' 3-h exposures in the FEC were in the ranges approximately 20-37 ppb and approximately 1.6-3 μg/m(3), respectively. Asthmatic subjects' perceived odor intensity and sensory (eye, nose, and throat) irritation ratings were generally lower than those of non-asthmatic subjects, possibly explaining why asthmatic subjects accept perceived air quality more than non-asthmatic subjects. However, asthmatic subjects' perceived physiological-like symptom ratings (flu, chest tightness, and headache) and concentrations of secreted salivary α-amylase were generally higher than those of non-asthmatic subjects. Asthmatic subjects had significantly lower accuracy than non-asthmatic subjects in a task that required higher concentration although they had higher work speed. Filter condition did not make any significant difference for subjects' responses. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Stepwise kinetic equilibrium models of quantitative polymerase chain reaction.

PubMed

Cobbs, Gary

2012-08-16

Numerous models for use in interpreting quantitative PCR (qPCR) data are present in recent literature. The most commonly used models assume the amplification in qPCR is exponential and fit an exponential model with a constant rate of increase to a select part of the curve. Kinetic theory may be used to model the annealing phase and does not assume constant efficiency of amplification. Mechanistic models describing the annealing phase with kinetic theory offer the most potential for accurate interpretation of qPCR data. Even so, they have not been thoroughly investigated and are rarely used for interpretation of qPCR data. New results for kinetic modeling of qPCR are presented. Two models are presented in which the efficiency of amplification is based on equilibrium solutions for the annealing phase of the qPCR process. Model 1 assumes annealing of complementary targets strands and annealing of target and primers are both reversible reactions and reach a dynamic equilibrium. Model 2 assumes all annealing reactions are nonreversible and equilibrium is static. Both models include the effect of primer concentration during the annealing phase. Analytic formulae are given for the equilibrium values of all single and double stranded molecules at the end of the annealing step. The equilibrium values are then used in a stepwise method to describe the whole qPCR process. Rate constants of kinetic models are the same for solutions that are identical except for possibly having different initial target concentrations. Analysis of qPCR curves from such solutions are thus analyzed by simultaneous non-linear curve fitting with the same rate constant values applying to all curves and each curve having a unique value for initial target concentration. The models were fit to two data sets for which the true initial target concentrations are known. Both models give better fit to observed qPCR data than other kinetic models present in the literature. They also give better estimates of initial target concentration. Model 1 was found to be slightly more robust than model 2 giving better estimates of initial target concentration when estimation of parameters was done for qPCR curves with very different initial target concentration. Both models may be used to estimate the initial absolute concentration of target sequence when a standard curve is not available. It is argued that the kinetic approach to modeling and interpreting quantitative PCR data has the potential to give more precise estimates of the true initial target concentrations than other methods currently used for analysis of qPCR data. The two models presented here give a unified model of the qPCR process in that they explain the shape of the qPCR curve for a wide variety of initial target concentrations.

Enhancing monellin production by Pichia pastoris at low cell induction concentration via effectively regulating methanol metabolism patterns and energy utilization efficiency

PubMed Central

Jia, Luqiang; Tu, Tingyong; Huai, Qiangqiang; Sun, Jiaowen; Chen, Shanshan; Li, Xin; Ding, Jian

2017-01-01

In heterologous protein productions by P. pastoris, methanol induction is generally initiated when cell concentration reaches very high density. The alternative strategy by initiating methanol induction at lower cells concentration was also reported to be effective in easing DO control, reducing toxic by-metabolites accumulation and increasing targeted proteins titers. However, the methanol/energy regulation mechanisms are seldom reported. We theoretically analyzed the methanol/energy metabolisms in protein expression process with the strategies of initiating induction at higher or lower cells concentrations, using monellin production as a prototype. When initiating induction at lower cells concentration and controlling induction temperature at 30°C, monellin concentration reached the highest levels of 2.62~2.71 g/L, which was 2.5~4.9 fold of those obtained with the strategy of initiating induction at higher cells concentration. With the desired induction strategy, 1) carbon metabolism ratio directing into the precursors synthesis route for monellin production reached the highest level of 65%, carbon metabolism ratios towards to precursors synthesis and ATP regeneration routes were regulated at relatively balanced levels; 2) monellin synthesis was completely cell growth associated, with the largest associated coefficient and higher specific growth rate; 3) theoretical NADH (energy) utilization efficiency η was the highest, and η stayed high levels (≥0.8) during most period (89%) within induction phase to supply sufficient energy in supporting monellin synthesis. PMID:28981536

Enhancing monellin production by Pichia pastoris at low cell induction concentration via effectively regulating methanol metabolism patterns and energy utilization efficiency.

PubMed

Jia, Luqiang; Tu, Tingyong; Huai, Qiangqiang; Sun, Jiaowen; Chen, Shanshan; Li, Xin; Shi, Zhongping; Ding, Jian

2017-01-01

In heterologous protein productions by P. pastoris, methanol induction is generally initiated when cell concentration reaches very high density. The alternative strategy by initiating methanol induction at lower cells concentration was also reported to be effective in easing DO control, reducing toxic by-metabolites accumulation and increasing targeted proteins titers. However, the methanol/energy regulation mechanisms are seldom reported. We theoretically analyzed the methanol/energy metabolisms in protein expression process with the strategies of initiating induction at higher or lower cells concentrations, using monellin production as a prototype. When initiating induction at lower cells concentration and controlling induction temperature at 30°C, monellin concentration reached the highest levels of 2.62~2.71 g/L, which was 2.5~4.9 fold of those obtained with the strategy of initiating induction at higher cells concentration. With the desired induction strategy, 1) carbon metabolism ratio directing into the precursors synthesis route for monellin production reached the highest level of 65%, carbon metabolism ratios towards to precursors synthesis and ATP regeneration routes were regulated at relatively balanced levels; 2) monellin synthesis was completely cell growth associated, with the largest associated coefficient and higher specific growth rate; 3) theoretical NADH (energy) utilization efficiency η was the highest, and η stayed high levels (≥0.8) during most period (89%) within induction phase to supply sufficient energy in supporting monellin synthesis.

Research in the design of high-performance reconfigurable systems

NASA Technical Reports Server (NTRS)

Slotnick, D. L.; Mcewan, S. D.; Spry, A. J.

1984-01-01

An initial design for the Bit Processor (BP) referred to in prior reports as the Processing Element or PE has been completed. Eight BP's, together with their supporting random-access memory, a 64 k x 9 ROM to perform addition, routing logic, and some additional logic, constitute the components of a single stage. An initial stage design is given. Stages may be combined to perform high-speed fixed or floating point arithmetic. Stages can be configured into a range of arithmetic modules that includes bit-serial one or two-dimensional arrays; one or two dimensional arrays fixed or floating point processors; and specialized uniprocessors, such as long-word arithmetic units. One to eight BP's represent a likely initial chip level. The Stage would then correspond to a first-level pluggable module. As both this project and VLSI CAD/CAM progress, however, it is expected that the chip level would migrate upward to the stage and, perhaps, ultimately the box level. The BP RAM, consisting of two banks, holds only operands and indices. Programs are at the box (high-level function) and system level. At the system level initial effort has been concentrated on specifying the tools needed to evaluate design alternatives.

Aluminum concentration and substrate temperature in chemical sprayed ZnO:Al thin solid films

NASA Astrophysics Data System (ADS)

Lozada, Erick Velázquez; Castañeda, L.; Aguilar, E. Austria

2018-02-01

The continuous interest in the synthesis and properties study of materials has permitted the development of semiconductor oxides. Zinc oxide (ZnO) with hexagonal wurzite structure is a wide band gap n-type semiconductor and interesting material over a wide range. Chemically sprayed aluminium-doped zinc oxide thin films (ZnO:Al) were deposited on soda-lime glass substrates starting from zinc pentanedionate and aluminium pentanedionate. The influence of both the dopant concentration in the starting solution and the substrate temperature on the composition, morphology, and transport properties of the ZnO:Al thin films were studied. The structure of all the ZnO:Al thin films was polycrystalline, and variation in the preferential growth with the aluminium content in the solution was observed: from an initial (002) growth in films with low Al content, switching to a predominance of (101) planes for heavily dopant regime. The crystallite size was found to decrease with doping concentration and range from 33 to 20 nm. First-order Raman scattering from ZnO:Al, all having the wurtzite structure. The assignments of the E2 mode in ZnO:Al differ from previous investigations. The film composition and the dopant concentration were determined by Auger Electron Spectroscopy (AES); these results showed that the films are almost stoichiometric ZnO. The optimum deposition conditions leading to conductive and transparent ZnO:Al thin films were also found. In this way a resistivity of 0.03 Ω-cm with a (002) preferential growth, were obtained in optimized ZnO:Al thin films.

Physiological Concentrations of Ascorbate Cannot Prevent the Potentially Damaging Reactions of Protein Radicals in Humans.

PubMed

Nauser, Thomas; Gebicki, Janusz M

2017-09-18

The principal initial biological targets of free radicals formed under conditions of oxidative stress are the proteins. The most common products of the interaction are carbon-centered alkyl radicals which react rapidly with oxygen to form peroxyl radicals and hydroperoxides. All these species are reactive, capable of propagating the free radical damage to enzymes, nucleic acids, lipids, and endogenous antioxidants, leading finally to the pathologies associated with oxidative stress. The best chance of preventing this chain of damage is in early repair of the protein radicals by antioxidants. Estimate of the effectiveness of the physiologically significant antioxidants requires knowledge of the antioxidant tissue concentrations and rate constants of their reaction with protein radicals. Previous studies by pulse radiolysis have shown that only ascorbate can repair the Trp and Tyr protein radicals before they form peroxyl radicals under physiological concentrations of oxygen. We have now extended this work to other protein C-centered radicals generated by hydroxyl radicals because these and many other free radicals formed under oxidative stress can produce secondary radicals on virtually any amino acid residue. Pulse radiolysis identified two classes of rate constants for reactions of protein radicals with ascorbate, a faster one in the range (9-60) × 10 7 M -1 s -1 and a slow one with a range of (0.5-2) × 10 7 M -1 s -1 . These results show that ascorbate can prevent further reactions of protein radicals only in the few human tissues where its concentration exceeds about 2.5 mM.

Growth of the facultative anaerobe Shewanella putrefaciens by elemental sulfur reduction

NASA Technical Reports Server (NTRS)

Moser, D. P.; Nealson, K. H.

1996-01-01

The growth of bacteria by dissimilatory elemental sulfur reduction is generally associated with obligate anaerobes and thermophiles in particular. Here we describe the sulfur-dependent growth of the facultatively anaerobic mesophile Shewanella putrefaciens. Six of nine representative S. putrefaciens isolates from a variety of environments proved able to grow by sulfur reduction, and strain MR-1 was chosen for further study. Growth was monitored in a minimal medium (usually with 0.05% Casamino Acids added as a growth stimulant) containing 30 mM lactate and limiting concentrations of elemental sulfur. When mechanisms were provided for the removal of the metabolic end product, H2S, measurable growth was obtained at sulfur concentrations of from 2 to 30 mM. Initial doubling times were ca. 1.5 h and substrate independent over the range of sulfur concentrations tested. In the cultures with the highest sulfur concentrations, cell numbers increased by greater than 400-fold after 48 h, reaching a maximum density of 6.8 x 10(8) cells ml-1. Yields were determined as total cell carbon and ranged from 1.7 to 5.9 g of C mol of S(0) consumed-1 in the presence of the amino acid supplement and from 0.9 to 3.4 g of C mol of S(0-1) in its absence. Several lines of evidence indicate that cell-to-sulfur contact is not required for growth. Approaches for the culture of sulfur-metabolizing bacteria and potential ecological implications of sulfur reduction in Shewanella-like heterotrophs are discussed.

Runoff of pharmaceuticals and personal care products following application of biosolids to an agricultural field.

PubMed

Topp, Edward; Monteiro, Sara C; Beck, Andrew; Coelho, Bonnie Ball; Boxall, Alistair B A; Duenk, Peter W; Kleywegt, Sonya; Lapen, David R; Payne, Michael; Sabourin, Lyne; Li, Hongxia; Metcalfe, Chris D

2008-06-15

Municipal biosolids are a source of nutrients for crop production. Beneficial Management Practices (BMPs) can be used to minimize the risk of contamination of adjacent water resources with chemical or microbial agents that are of public or environmental health concern. In this field study, we applied biosolids slurry at a commercial rate using either subsurface injection or broadcast application followed by incorporation. Precipitation was simulated at 1, 3, 7, 22, 36 and 266 days post-application on 2 m(2) microplots to evaluate surface runoff of 9 model pharmaceuticals and personal care products (PPCPs), atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, ibuprofen, acetaminophen, sulfamethoxazole and triclosan. In runoff from the injected plots, concentrations of the model PPCPs were generally below the limits of quantitation. In contrast, in the broadcast application treatment, the concentrations of atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, sulfamethoxazole and triclosan on the day following application ranged from 70-1477 ng L(-1) in runoff and generally declined thereafter with first order kinetics. The total mass of PPCPs mobilized in surface runoff per m(2) of the field ranged from 0.63 microg for atenolol to 21.1 microg for ibuprofen. For ibuprofen and acetaminophen, concentrations in runoff first decreased and then increased, suggesting that these drugs were initially chemically or physically sequestered in the biosolids slurry, and subsequently released in the soil. Carbamazepine and triclosan were detected at low concentrations in a runoff event 266 days after broadcast application. Overall, this study showed that injection of biosolids slurry below the soil surface could effectively eliminate surface runoff of PPCPs.

Microfluidics and numerical simulation as methods for standardization of zebrafish sperm cell activation

PubMed Central

Scherr, Thomas; Knapp, Gerald L.; Guitreau, Amy; Park, Daniel Sang-Won; Tiersch, Terrence; Nandakumar, Krishnaswamy

2017-01-01

Sperm cell activation plays a critical role in a range of biological and engineering processes, from fertilization to cryopreservation protocol evaluation. Across a range of species, ionic and osmotic effects have been discovered that lead to activation. Sperm cells of zebrafish (Danio rerio) initiate motility in a hypoosmotic environment. In this study, we employ a microfluidic mixer for the purpose of rapidly diluting the extracellular medium to initiate the onset of cell motility. The use of a microchannel offers a rapid and reproducible mixing profile throughout the device. This greatly reduces variability from trial to trial relative to the current methods of analysis. Coupling these experiments with numerical simulations, we were able to investigate the dynamics of intracellular osmolality as each cell moves along its path through the micromixer. Our results suggest that intracellular osmolality, and hence intracellular ion concentration, only slightly decreases, contrary to the common thought that larger changes in these parameters are required for activation. Utilizing this framework, microfluidics for controlled extracellular environments and associated numerical modeling, has practical applicability in standardizing high-throughput aquatic sperm activation, and more fundamentally, investigations of the intracellular environment leading to motility. PMID:26026298

Progenitor cells from different zones of human cartilage and their correlation with histopathological osteoarthritis progression.

PubMed

Mantripragada, Venkata P; Bova, Wesley A; Boehm, Cynthia; Piuzzi, Nicolas S; Obuchowski, Nancy A; Midura, Ronald J; Muschler, George F

2018-06-01

Cell-based therapies development for the treatment of osteoarthritis (OA) requires an understanding of the disease progression and attributes of the cells resident in cartilage. This study focused on quantitative assessment of the concentration and biological potential of stem and progenitor cells resident in different zones of cartilage displaying macroscopic Outerbridge grade 1-2 OA, and their correlation with OA progression based on established histologic scoring system. Lateral femoral condyles were collected from 15 patients with idiopathic OA and varus knees undergoing total knee arthroplasty. Superficial(C sp , top ∼ 500 µm) and deep cartilage(C dp ) was separated. Chondrogenic Connective Tissue Progenitors (CTP-C) were assayed by standardized Colony-Forming-Unit assay using automated image analysis (Colonyze TM ) based on ASTM standard F-2944-12. Cell concentration (cells/mg) was significantly greater in C sp (median: 7,000; range: 3,440-17,600) than C dp (median: 5,340; range: 3,393-9,660), p = 0.039. Prevalence (CTPs/million cells) was not different between C sp (median: 1,274; range: 0-3,898) and C dp (median:1,365; range:0-6,330), p = 0.42. In vitro performance of CTP-C progeny varied widely within and between patients, manifest by variation in colony size and morphology. Mean histopathological Mankin score was 4.7 (SD = 1.2), representing mild to moderate OA. Tidemark breach by blood vessels was associated with lower C sp cell concentration (p = 0.02). Matrix degradation was associated with lower C dp cell and CTP-C concentration (p = 0.015 and p = 0.095, respectively), independent of articular surface changes. These findings suggest that the initiation of OA may occur in either superficial or deep zones. The pathological changes affect CTP-Cs in C sp and C dp cartilage zones differently. The heterogeneity among the available CTP-Cs in C sp and C dp suggests performance-based selection to optimize cell-sourcing strategies for therapy. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1728-1738, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Aerosol formation by ozonolysis of α- and β-pinene with initial concentrations below 1 ppb

NASA Astrophysics Data System (ADS)

Saathoff, Harald; Naumann, Karl-Heinz; Möhler, Ottmar

2014-05-01

Secondary organic aerosols (SOA) from the oxidation of biogenic volatile organic compounds (BVOC) are a large fraction of the tropospheric aerosol especially over tropical continental regions. The dominant SOA forming compounds are monoterpenes of which pinene is the most abundant. The reactions of monoterpenes with OH radicals, NO3 radicals, and ozone yield secondary organic aerosol mass in highly variable yields. Despite the various studies on SOA formation the influence of temperature and precursor concentrations on SOA yields are still major uncertainties in tropospheric aerosol models. In previous studies we observed a negative temperature dependence of SOA yields for SOA from ozonolysis α-pinene and limonene (Saathoff et al., 2009). However, this study as well as most of the literature data for measured SOA yields is limited to terpene concentrations of several ppb and higher (e.g. Bernard et al., 2012), hence about an order of magnitude higher than terpene concentrations even near their sources. Monoterpene concentrations in and above tropical or boral forests reach values up to a few tenth of a ppb during daytime decreasing rapidly with altitude in the boundary layer (Kesselmeier et al. 2000; Boy et al., 2004). Therefore we investigated the yield of SOA material from the ozonolysis of α- and β-pinene under simulated tropospheric conditions in the large aerosol chamber AIDA on time scales of several hours and for terpene concentrations between 0.1 and 1 ppb. The temperatures investigated were 243, 274, and 296 K with relative humidities ranging from 25% to 41%. The organic aerosol was generated by controlled oxidation with an excess of ozone (220-930 ppb) and the aerosol yield is calculated from size distributions measured with differential mobility analysers (SMPS, TSI, 3071 & 3080N) in the size range between 2 and 820 nm. On the basis of the measured initial particle size distribution, particle number concentration (CPC, TSI, 3775, 3776, 3022), and trace gas evolution model calculations were done using the aerosol model COSIMA (Naumann, 2003; Saathoff et al., 2009) supplemented by an improved SOA module in combination with the master chemical mechanism (MCM 3.2). As previously reported for higher SOA concentrations the overall SOA yields from ozonolysis of α- and β-pinene increase significantly with decreasing temperature. However, compared to the yields extrapolated from experiments done with higher terpene concentrations the SOA yields at ambient like concentrations are surprisingly high. They reach values of up to 20% at 243 K for organic aerosol mass concentrations of about 0.5 µg m-3 even without additional seed aerosol. This paper discusses the temperature dependent SOA yields from the ozonolysis of α-pinene and β-pinene in comparison with data from literature. Bernard et al., (2012) J. Aerosol Sci. 43, 14-30. Boy et al., (2004) Atmos. Chem. Phys. 4, 657-678. Kesselmeier et al., (2000) Atmos. Environ. 34, 4063-4072 Naumann (2003) J. Aerosol Sci. 34 (10), 1371-1397. Saathoff et al., (2009) Atmos. Chem. Phys. 9 (5), 1551-1577.

Modeling of the adsorptive removal of arsenic(III) using plant biomass: a bioremedial approach

NASA Astrophysics Data System (ADS)

Roy, Palas; Dey, Uttiya; Chattoraj, Soumya; Mukhopadhyay, Debasis; Mondal, Naba Kumar

2017-06-01

In the present work, the possibility of using a non-conventional finely ground (250 μm) Azadirachta indica (neem) bark powder [AiBP] has been tested as a low-cost biosorbent for the removal of arsenic(III) from water. The removal of As(III) was studied by performing a series of biosorption experiments (batch and column). The biosorption behavior of As(III) for batch and column operations were examined in the concentration ranges of 50-500 µg L-1 and 500.0-2000.0 µg L-1, respectively. Under optimized batch conditions, the AiBP could remove up to 89.96 % of As(III) in water system. The artificial neural network (ANN) model was developed from batch experimental data sets which provided reasonable predictive performance ( R 2 = 0.961; 0.954) of As(III) biosorption. In batch operation, the initial As(III) concentration had the most significant impact on the biosorption process. For column operation, central composite design (CCD) was applied to investigate the influence on the breakthrough time for optimization of As(III) biosorption process and evaluation of interacting effects of different operating variables. The optimized result of CCD revealed that the AiBP was an effective and economically feasible biosorbent with maximum breakthrough time of 653.9 min, when the independent variables were retained at 2.0 g AiBP dose, 2000.0 µg L-1 initial As(III) concentrations, and 3.0 mL min-1 flow rate, at maximum desirability value of 0.969.

Support for the initial attachment, growth and differentiation of MG-63 cells: a comparison between nano-size hydroxyapatite and micro-size hydroxyapatite in composites

PubMed Central

Filová, Elena; Suchý, Tomáš; Sucharda, Zbyněk; Šupová, Monika; Žaloudková, Margit; Balík, Karel; Lisá, Věra; Šlouf, Miroslav; Bačáková, Lucie

2014-01-01

Hydroxyapatite (HA) is considered to be a bioactive material that favorably influences the adhesion, growth, and osteogenic differentiation of osteoblasts. To optimize the cell response on the hydroxyapatite composite, it is desirable to assess the optimum concentration and also the optimum particle size. The aim of our study was to prepare composite materials made of polydimethylsiloxane, polyamide, and nano-sized (N) or micro-sized (M) HA, with an HA content of 0%, 2%, 5%, 10%, 15%, 20%, 25% (v/v) (referred to as N0–N25 or M0–M25), and to evaluate them in vitro in cultures with human osteoblast-like MG-63 cells. For clinical applications, fast osseointegration of the implant into the bone is essential. We observed the greatest initial cell adhesion on composites M10 and N5. Nano-sized HA supported cell growth, especially during the first 3 days of culture. On composites with micro-size HA (2%–15%), MG-63 cells reached the highest densities on day 7. Samples M20 and M25, however, were toxic for MG-63 cells, although these composites supported the production of osteocalcin in these cells. On N2, a higher concentration of osteopontin was found in MG-63 cells. For biomedical applications, the concentration range of 5%–15% (v/v) nano-size or micro-size HA seems to be optimum. PMID:25125978

Disodium N,N-bis-(dithiocarboxy)ethanediamine: synthesis, performance, and mechanism of action toward trace ethylenediaminetetraacetic acid copper (II).

PubMed

Xiao, Xiao; Ye, Maoyou; Yan, Pingfang; Qiu, Yiqin; Sun, Shuiyu; Ren, Jie; Dai, Yongkang; Han, Dajian

2016-10-01

A new effective multi-dithiocarbamate heavy metal precipitant, disodium N,N-bis-(dithiocarboxy) ethanediamine (BDE), was synthesized by mixing ethanediamine with carbon disulfide under alkaline conditions, and it was utilized for removing trace ethylenediaminetetraacetic acid copper (II) (EDTA-Cu) from wastewater. Its structure was confirmed by ultraviolet spectra, Fourier transform infrared spectra, scanning electron microscopy, thermogravimetric analysis, and elemental analysis. The removal performance of EDTA-Cu by BDE was evaluated according to BDE dosage, initial concentration, pH, and reaction time through single-factor experiments. With the optimized conditions of a pH range of 3-9, dosage ratio of BDE/Cu of 1:1, PAM dosage of 1 mg/L, and reaction time of 4 min, the removal efficiency of Cu(2+) was more than 98 % from simulated wastewater containing EDTA-Cu with initial concentrations of 5-100 mg/L. Treatment of actual EDTA-Cu wastewater showed that BDE performed superior effectiveness, and the average residential concentration of Cu(2+) was 0.115 mg/L. Besides, the stability of chelated precipitate and the reaction mechanism of BDE and EDTA-Cu were also introduced. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the chelated precipitate was non-hazardous and stable in weak acid and alkaline conditions. The BDE reacts with EDTA-Cu at a stoichiometric ratio, and the removal of Cu(2+) was predominantly achieved through the replacement reaction of BDE and EDTA-Cu.

Biotransformation of gabapentin in surface water matrices under different redox conditions and the occurrence of one major TP in the aquatic environment.

PubMed

Henning, Nina; Kunkel, Uwe; Wick, Arne; Ternes, Thomas A

2018-06-15

Laboratory-scale incubation experiments in water/sediment systems were conducted to test the transformation behavior of the anticonvulsant gabapentin (GBP) under different environmental conditions (aerobic, anaerobic, with abiotic controls). GBP was transformed by biological processes as it was eliminated quickly under aerobic conditions (dissipation time 50% of initial concentration (DT 50 ): 2-7 days) whereas no decrease was observed under anaerobic conditions. Measurements via high resolution mass spectrometry (LC-Orbitrap-MS) revealed eight biological transformation products (TPs). Three of them were identified with reference standards (GBP-Lactam, TP186, TP213), while for the other five TPs tentative structures were proposed from information by MS 2 /MS 3 experiments. Furthermore, the quantitatively most relevant TP GBP-Lactam was formed via intramolecular amidation (up to 18% of initial GBP concentration). Incubation experiments with GBP-Lactam revealed a higher stability against biotic degradation (DT 50 : 12 days) in contrast to GBP, while it was stable under anaerobic and abiotic conditions. Besides GBP, GBP-Lactam was detected in surface water in the μg L -1 range. Finally, GBP and GBP-Lactam were found in potable water with concentrations up to 0.64 and 0.07 μg L -1 , respectively. According to the elevated environmental persistence of GBP-Lactam compared to GBP and its presumed enhanced toxicity, we recommend to involve GBP-Lactam into monitoring programs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradations of acetaminophen via a K2S2O8-doped TiO2 photocatalyst under visible light irradiation.

PubMed

Lin, Justin Chun-Te; de Luna, Mark Daniel G; Aranzamendez, Graziel L; Lu, Ming-Chun

2016-07-01

Acetaminophen (ACT) is a mild analgesic commonly used for relief of fever, headache and some minor pains. It had been detected in both fixed factory-discharged wastewaters, and diverse sources, e.g. surface waters during festival events. Degradation of such trace emergent pollutants by titanium dioxide (TiO2) photocatalysts is a common approach; however, the band gap that can be utilized in the UV range is limited. In order to extend downward the energy required to excite the photocatalytic material, doping with potassium peroxodisulfate (K2S2O8) by a sol-gel method was done in this work. The visible-light active photocatalyst was tested on the degradation of ACT under four parameters including: initial ACT concentration, catalyst dose, initial pH, and system temperature. Optimal conditions, which achieved 100% ACT degradation, were obtained by using 0.1 mM ACT initial concentration, catalyst dose of 1 g L(-1), initial pH of 9.0 and system temperature of 22 °C at the end of 9-h irradiation. Meanwhile, three types of degradation kinetic models (i.e. zero, pseudo first and second order) were tested. The feasible model followed a pseudo-first order model with the computed constant (kapp) of 7.29 × 10(-3) min(-1). The present study provides a better photocatalytic degradation route by K2S2O8-modified TiO2 in comparison with pristine TiO2, in wastewater treatment dealing with ACT and other persistent organic pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anodic oxidation of coke oven wastewater: Multiparameter optimization for simultaneous removal of cyanide, COD and phenol.

PubMed

Sasidharan Pillai, Indu M; Gupta, Ashok K

2016-07-01

Anodic oxidation of industrial wastewater from a coke oven plant having cyanide including thiocyanate (280 mg L(-1)), chemical oxygen demand (COD - 1520 mg L(-1)) and phenol (900 mg L(-1)) was carried out using a novel PbO2 anode. From univariate optimization study, low NaCl concentration, acidic pH, high current density and temperature were found beneficial for the oxidation. Multivariate optimization was performed with cyanide including thiocyanate, COD and phenol removal efficiencies as a function of changes in initial pH, NaCl concentration and current density using Box-Behnken experimental design. Optimization was performed for maximizing the removal efficiencies of these three parameters simultaneously. The optimum condition was obtained as initial pH 3.95, NaCl as 1 g L(-1) and current density of 6.7 mA cm(-2), for which the predicted removal efficiencies were 99.6%, 86.7% and 99.7% for cyanide including thiocyanate, COD and phenol respectively. It was in agreement with the values obtained experimentally as 99.1%, 85.2% and 99.7% respectively for these parameters. The optimum conditions with initial pH constrained to a range of 6-8 was initial pH 6, NaCl as 1.31 g L(-1) and current density as 6.7 mA cm(-2). The predicted removal efficiencies were 99%, 86.7% and 99.6% for the three parameters. The efficiencies obtained experimentally were in agreement at 99%, 87.8% and 99.6% respectively. The cost of operation for degradation at optimum conditions was calculated as 21.4 USD m(-3). Copyright © 2016 Elsevier Ltd. All rights reserved.