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1

Starvation Ketoacidosis: A Cause of Severe Anion Gap Metabolic Acidosis in Pregnancy  

PubMed Central

Pregnancy is a diabetogenic state characterized by relative insulin resistance, enhanced lipolysis, elevated free fatty acids and increased ketogenesis. In this setting, short period of starvation can precipitate ketoacidosis. This sequence of events is recognized as “accelerated starvation.” Metabolic acidosis during pregnancy may have adverse impact on fetal neural development including impaired intelligence and fetal demise. Short periods of starvation during pregnancy may present as severe anion gap metabolic acidosis (AGMA). We present a 41-year-old female in her 32nd week of pregnancy, admitted with severe AGMA with pH 7.16, anion gap 31, and bicarbonate of 5?mg/dL with normal lactate levels. She was intubated and accepted to medical intensive care unit. Urine and serum acetone were positive. Evaluation for all causes of AGMA was negative. The diagnosis of starvation ketoacidosis was established in absence of other causes of AGMA. Intravenous fluids, dextrose, thiamine, and folic acid were administered with resolution of acidosis, early extubation, and subsequent normal delivery of a healthy baby at full term. Rapid reversal of acidosis and favorable outcome are achieved with early administration of dextrose containing fluids. PMID:24963418

Venkatram, Sindhaghatta; Diaz-Fuentes, Gilda

2014-01-01

2

Metabolic alkalosis from unsuspected ingestion: use of urine pH and anion gap.  

PubMed

Underlying causes of metabolic alkalosis may be evident from history, evaluation of effective circulatory volume, and measurement of urine chloride concentration. However, identification of causes may be difficult for certain conditions associated with clandestine behaviors, such as surreptitious vomiting, use of drugs or herbal supplements with mineralocorticoid activity, abuse of laxatives or diuretics, and long-term use of alkalis. In these circumstances, clinicians often are bewildered by unexplained metabolic alkalosis from an incomplete history or persistent deception by the patient, leading to misdiagnosis and poor outcome. We present a case of severe metabolic alkalosis and hypokalemia with a borderline urine chloride concentration in an alcoholic patient treated with a thiazide. The cause of the patient's metabolic alkalosis eventually was linked to surreptitious ingestion of baking soda. This case highlights the necessity of a high index of suspicion for the diverse clandestine behaviors that can cause metabolic alkalosis and the usefulness of urine pH and anion gap in its differential diagnosis. PMID:22265393

Yi, Joo-Hark; Han, Sang-Woong; Song, June-Seok; Kim, Ho-Jung

2012-04-01

3

High anion gap refractory metabolic acidosis as a critical presentation of endosulfan poisoning  

PubMed Central

Organochloride insecticides are chlorinated cyclic hydrocarbons. One of such insecticides is endosulfan (6,7,8,9,10-10 hexachloro 1,5,5a,6,9,9a-hexahydro-6-methano-2,4,3-hexadithioxanthiep in 3-oxide) and it has been widely used in agriculture since 1960. The uncontrolled use of these compounds in developing countries has resulted in the deaths of animals and humans. Characteristic clinical signs following acute exposure are indicative of CNS disturbances or overstimulation. Mortality and morbidity rates are high and there is no specific antidote. We present an uncommon presentation of endosulfan poisoning in a 32-year-old male with high anion gap severe refractory metabolic acidosis. The patient was treated with continuous renal replacement therapy and was salvaged. Till date, there is no case report from India for endosulfan poisoning with severe metabolic acidosis and hypotension. Through this case report, we emphasize the role of continuous renal replacement therapy as a rescue therapy for endosulfan poisoning with severe refractory metabolic acidosis and hypotension, even though it is a non dialyzable poison. PMID:21845009

Sharma, Raj Kumar; Kaul, Anupama; Gupta, Anurag; Bhadauria, Dharmendra; Prasad, Narayan; Jain, Apoorva; Gurjar, M.; Rao, Bhaskar P.

2011-01-01

4

The serum anion gap is altered in early kidney disease and associates with mortality  

PubMed Central

It is well known that uremia causes an increase in the serum anion gap; however, whether changes in the anion gap occur earlier in the course of chronic kidney disease is not known. Here we investigated whether different measures of the anion gap, as a marker of kidney function, are associated with mortality. To do this we analyzed the available laboratory data of 11,957 adults in the National Health and Nutrition Examination Survey 1999–2004 to calculate anion gap using the traditional method, or one that was albumin-adjusted, as well as a full anion gap reflecting other electrolytes. A significant elevation in the traditional anion gap was seen only with an estimated glomerular filtration rate (eGFR) less than 45 mL/min/1.73m2, whereas increases in the albumin-adjusted and full anion gap were found with eGFRs less than 60 or 90mL/min/1.73m2, respectively. Higher levels of each anion gap were associated with an increased risk of all-cause mortality after adjustment for age, gender, race/ethnicity, and eGFR. After adjustment for additional covariates including body-mass index and comorbidities, higher levels of the albumin-adjusted and full anion gap were associated with mortality (relative hazard for highest compared to the lowest quartile were 1.62 and 1.64, respectively). Thus, higher levels of anion gap are present in individuals with less advanced kidney disease than previously recognized, and are associated with increased risk of mortality. Further study is needed to identify the unmeasured anions and to determine their physiologic significance. PMID:22622500

Abramowitz, Matthew K.; Hostetter, Thomas H.; Melamed, Michal L.

2012-01-01

5

Metformin-induced lactic acidosis with emphasis on the anion gap  

PubMed Central

The presence of an anion gap in a diabetic patient, especially if associated with evidence of compromised renal function, should prompt clinicians to consider metformin as a contributing factor. This consideration is especially important in patients with severe anion gaps associated with lactic acidosis out of proportion to the patient's clinical presentation. PMID:25552792

Blough, Britton; Moreland, Amber

2015-01-01

6

Metformin-induced lactic acidosis with emphasis on the anion gap.  

PubMed

The presence of an anion gap in a diabetic patient, especially if associated with evidence of compromised renal function, should prompt clinicians to consider metformin as a contributing factor. This consideration is especially important in patients with severe anion gaps associated with lactic acidosis out of proportion to the patient's clinical presentation. PMID:25552792

Blough, Britton; Moreland, Amber; Mora, Adan

2015-01-01

7

Near-fatal persistent anion- and osmolal-gap acidosis due to massive gamma-butyrolactone/ethanol intoxication.  

PubMed

We report a case of an ethanol and massive gamma-butyrolactone (GBL) intoxication, the precursor of the recreational drug gamma-hydroxybutyric acid (GHB), resulting in life-threatening metabolic acidosis (pH 6.5) with a highly increased anion- and osmolal gap. Rapid analysis using gas chromatography revealed a GHB plasma concentration of 4400?mg/L, far above the upper limit concentration of 1000?mg/L found in adult fatalities attributed to GBL. Full recovery was established following supportive treatment including haemodialysis. This is the first report of a combined ethanol/GBL intoxication as a cause of high serum anion- and osmolal-gap metabolic acidosis. PMID:25205856

Heytens, Luc; Neels, Hugo; Van Regenmortel, Niels; van den Brink, Wim; Henckes, Manu; Schouwers, Sofie; Dockx, Greet; Crunelle, Cleo L

2014-09-01

8

Mammalian Metabolism of ?-Carotene: Gaps in Knowledge  

PubMed Central

?-carotene is the most abundant provitamin A carotenoid in human diet and tissues. It exerts a number of beneficial functions in mammals, including humans, owing to its ability to generate vitamin A as well as to emerging crucial signaling functions of its metabolites. Even though ?-carotene is generally considered a safer form of vitamin A due to its highly regulated intestinal absorption, detrimental effects have also been ascribed to its intake, at least under specific circumstances. A better understanding of the metabolism of ?-carotene is still needed to unequivocally discriminate the conditions under which it may exert beneficial or detrimental effects on human health and thus to enable the formulation of dietary recommendations adequate for different groups of individuals and populations worldwide. Here we provide a general overview of the metabolism of this vitamin A precursor in mammals with the aim of identifying the gaps in knowledge that call for immediate attention. We highlight the main questions that remain to be answered in regards to the cleavage, uptake, extracellular and intracellular transport of ?-carotene as well as the interactions between the metabolism of ?-carotene and that of other macronutrients such as lipids. PMID:24288025

Shete, Varsha; Quadro, Loredana

2013-01-01

9

Influence of Anionic Salts on Bone Metabolism in Periparturient Dairy Goats and Sheep  

Microsoft Academic Search

The purpose of the present study was to investigate the influence of diets supplemented with anionic salts on bone metabolism of dairy goats and sheep. Twelve Saanen goats and 12 Ostfrisean milk sheep (fourth lac- tation) were divided into 2 groups each (sheep control (SC), goat control (GC); sheep anionic salts (SA), goat anionic salts (GA)). Each group was fed

A. Liesegang

2008-01-01

10

Lower serum bicarbonate and a higher anion gap are associated with lower cardiorespiratory fitness in young adults  

PubMed Central

Lower levels of serum bicarbonate and a higher anion gap have been associated with insulin resistance and hypertension in the general population. Whether these associations extend to other cardiovascular disease risk factors is unknown. To clarify this, we examined the association of serum bicarbonate and anion gap with cardiorespiratory fitness in 2714 adults aged 20–49 years in the 1999–2004 National Health and Nutrition Examination Survey. The mean serum bicarbonate was 24.6 mEq/L and the mean anion gap was 10.26 mEq/L, with fitness determined by submaximal exercise testing. After multivariable adjustment, gender, length of fasting, soft drink consumption, systolic blood pressure, serum phosphate, and hemoglobin were independently associated with both the serum bicarbonate and the anion gap. Low fitness was most prevalent among those in the lowest quartile of serum bicarbonate or highest quartile of anion gap. After multivariable adjustment, a one standard deviation higher serum bicarbonate or anion gap was associated with an odds ratio for low fitness of 0.80 (95% CI 0.70–0.91) and 1.30 (95% CI 1.15–1.48), respectively. The association of bicarbonate with fitness may be mediated by differences in lean body mass. Thus, lower levels of serum bicarbonate and higher levels of anion gap are associated with lower cardiorespiratory fitness in adults aged 20–49 years in the general population. PMID:22297677

Abramowitz, Matthew K.; Hostetter, Thomas H.; Melamed, Michal L.

2012-01-01

11

Anion Gap Toxicity in Alloxan Induced Type 2 Diabetic Rats Treated with Antidiabetic Noncytotoxic Bioactive Compounds of Ethanolic Extract of Moringa oleifera.  

PubMed

Moringa oleifera (MO) is used for a number of therapeutic purposes. This raises the question of safety and possible toxicity. The objective of the study was to ascertain the safety and possible metabolic toxicity in comparison with metformin, a known drug associated with acidosis. Animals confirmed with diabetes were grouped into 2 groups. The control group only received oral dose of PBS while the test group was treated with ethanolic extract of MO orally twice daily for 5-6 days. Data showed that the extract significantly lowered glucose level to normal values and did not cause any significant cytotoxicity compared to the control group (P = 0.0698); there was no gain in weight between the MO treated and the control groups (P > 0.8115). However, data showed that treatment with an ethanolic extract of MO caused a decrease in bicarbonate (P < 0.0001), and more than twofold increase in anion gap (P < 0.0001); metformin treatment also decreased bicarbonate (P < 0.0001) and resulted in a threefold increase in anion gap (P < 0.0001). Conclusively, these data show that while MO appears to have antidiabetic and noncytotoxic properties, it is associated with statistically significant anion gap acidosis in alloxan induced type 2 diabetic rats. PMID:25548560

Omabe, Maxwell; Nwudele, Chibueze; Omabe, Kenneth Nwobini; Okorocha, Albert Egwu

2014-01-01

12

Anion Gap Toxicity in Alloxan Induced Type 2 Diabetic Rats Treated with Antidiabetic Noncytotoxic Bioactive Compounds of Ethanolic Extract of Moringa oleifera  

PubMed Central

Moringa oleifera (MO) is used for a number of therapeutic purposes. This raises the question of safety and possible toxicity. The objective of the study was to ascertain the safety and possible metabolic toxicity in comparison with metformin, a known drug associated with acidosis. Animals confirmed with diabetes were grouped into 2 groups. The control group only received oral dose of PBS while the test group was treated with ethanolic extract of MO orally twice daily for 5-6 days. Data showed that the extract significantly lowered glucose level to normal values and did not cause any significant cytotoxicity compared to the control group (P = 0.0698); there was no gain in weight between the MO treated and the control groups (P > 0.8115). However, data showed that treatment with an ethanolic extract of MO caused a decrease in bicarbonate (P < 0.0001), and more than twofold increase in anion gap (P < 0.0001); metformin treatment also decreased bicarbonate (P < 0.0001) and resulted in a threefold increase in anion gap (P < 0.0001). Conclusively, these data show that while MO appears to have antidiabetic and noncytotoxic properties, it is associated with statistically significant anion gap acidosis in alloxan induced type 2 diabetic rats.

2014-01-01

13

Paying Attention to Dietary Cation-Anion Balance Can Mean More Milk and Fewer Metabolic Problems  

Microsoft Academic Search

Charles C. Stallings, Professor and Extension Dairy Scientist, Virginia Tech Dietary cation-anion difference (DCAD) or balance can be used to alter the metabolic status of both dry and lactating cows. Research demonstrates that dry cows can benefit from a mild systemic acidosis at calv - ing, resulting in improved bone calcium mobilization. Lactating cows benefit from a mild systemic alkalosis

Mark A. McCann; Alma C. Hobbs

14

Influence of anionic salts on bone metabolism in periparturient dairy goats and sheep.  

PubMed

The purpose of the present study was to investigate the influence of diets supplemented with anionic salts on bone metabolism of dairy goats and sheep. Twelve Saanen goats and 12 Ostfrisean milk sheep (fourth lactation) were divided into 2 groups each [sheep control (SC), goat control (GC); sheep anionic salts (SA), goat anionic salts (GA)]. Each group was fed a different diet in the last 10 d of gestation. Groups SC and GC received a normal diet according to the requirements of goats and sheep in this stage of gestation. Groups SA and GA received supplemental anionic salts. The dietary cation-anion difference (DCAD) was +524 (SC) and +515 (GC) vs. -163 (SA) and -164 (GA) mEq/kg of dry matter. Blood and urine samples were collected daily until parturition. Serum Ca, P, Mg, serum crosslaps (CTX), osteocalcin, 1,25-dihydroxy-vitamin D (VITD), urinary pH, and urinary Ca concentrations were analyzed. Bone mineral density and bone mineral content were measured with peripheral quantitative computer tomography. The bone resorption marker CTX showed significant differences between the animals supplemented with anionic salts and the control animals in goats, but not in sheep. The goats receiving anionic salts had greater CTX concentrations throughout the administration of the salts. In sheep, a difference was only observed on the day of parturition. Similar observations were made in VITD concentrations, although a significant difference between the goat groups was only observed 3 d prepartum. The bone formation marker osteocalcin was lower prepartum in the animals supplemented with anionic salts. The urinary pH was lower in the SA and GA animals, whereas urinary Ca concentrations were greater. Bone mineral content and bone mineral density decreased in all groups around parturition. In conclusion, this experiment showed that the addition of anionic salts in goats led to greater bone resorption rates while on this feeding regimen. It can be concluded that the anionic salts induced a mild metabolic acidosis with all its effects on calcium metabolism. These effects were not evident in milk sheep. PMID:18487668

Liesegang, A

2008-06-01

15

Anion exchange and volume regulation during metabolic blockade of renal cortical slices.  

PubMed Central

1. The development of swelling of rat and guinea-pig renal cortical slices was studied after metabolic blockade (hypoxia plus glycolytic blockade with iodo-acetic acid) and/or exposure to 'isotonic' high potassium, no sodium solution. 2. Swelling was greater after exposure to oxygenated high potassium solution than after metabolic blockade in physiologic Krebs-Henseleit solution. Swelling was reduced after metabolic blockade in high potassium solution compared to incubation in oxygenated high potassium solution. Increasing periods of transient metabolic blockade in Krebs-Henseleit solution progressively blunted swelling when slices were subsequently incubated in oxygenated high potassium solution. 3. Metabolic blockade in Krebs-Henseleit solution resulted in marked reductions in potassium and increases in sodium. Incubation in high potassium solution resulted in marked increases in potassium and similar low levels of sodium regardless of associated interventions. Metabolic blockade in both media resulted in significantly greater increases in renal cortical chloride than in monovalent cations (potassium plus sodium). Incubation in oxygenated high potassium solution was associated with similar increases in renal cortical chloride and total monovalent cations. 4. Renal cortical losses of solids and protein and increases in renal cortical inulin space were greater after metabolic blockade than after incubation under oxygenated conditions regardless of the incubation media. 5. These data support the conclusion that during metabolic blockade there is a significant replacement of larger intracellular anions by extracellular chloride. The loss of osmotically active intracellular anions limits the increase in renal cortical volume during metabolic inhibition and exposure to high potassium solution. PMID:536917

Pine, M B; Rhodes, D; Thorp, K; Tsai, Y

1979-01-01

16

Metabolic Acidosis and Strong Ion Gap in Critically Ill Patients with Acute Kidney Injury  

PubMed Central

Purpose. To determine the influence of physicochemical parameters on survival in metabolic acidosis (MA) and acute kidney injury (AKI) patients. Materials and Methods. Seventy-eight MA patients were collected and assigned to AKI or non-AKI group. We analyzed the physiochemical parameters on survival at 24?h, 72?h, 1 week, 1 month, and 3 months after AKI. Results. Mortality rate was higher in the AKI group. AKI group had higher anion gap (AG), strong ion gap (SIG), and apparent strong ion difference (SIDa) values than non-AKI group. SIG value was higher in the AKI survivors than nonsurvivors and this value was correlated serum creatinine, phosphate, albumin, and chloride levels. SIG and serum albumin are negatively correlated with Acute Physiology and Chronic Health Evaluation IV scores. AG was associated with mortality at 1 and 3 months post-AKI, whereas SIG value was associated with mortality at 24?h, 72?h, 1 week, 1 month, and 3 months post-AKI. Conclusions. Whether high or low SIG values correlate with mortality in MA patients with AKI depends on its correlation with serum creatinine, chloride, albumin, and phosphate (P) levels. AG predicts short-term mortality and SIG value predicts both short- and long-term mortality among MA patients with AKI. PMID:25162029

Zheng, Cai-Mei; Liu, Wen-Chih; Zheng, Jing-Quan; Liao, Min-Tser; Ma, Wen-Ya; Lu, Chien-Lin; Lu, Kuo-Cheng

2014-01-01

17

Regulation of AE1 anion exchanger and H+ATPase in rat cortex by acute metabolic acidosis and alkalosis  

Microsoft Academic Search

Regulation of AE1 anion exchanger and H+-ATPase in rat cortex by acute metabolic acidosis and alkalosis. The cortical collecting duct (CCD) mediates net secretion or reabsorption of protons according to systemic acid\\/base status. Using indirect immunofluorescence, we examined the localization and abundance of the vacuolar H+-ATPase and the AE1 anion exchanger in intercalated cells (IC) of rat kidney connecting segment

Ivan Saboli?; Dennis Brown; Stephen L Gluck; Seth L Alper

1997-01-01

18

Band-gap-confinement and image-state-recapture effects in the survival of anions scattered from metal surfaces  

SciTech Connect

The resonant charge transfer process in the collision of hydrogen anions with metal surfaces is described within a single-active-electron wave-packet propagation method. The ion-survival probability is found to be strongly enhanced at two different surface-specific perpendicular velocities of the ion. It is shown that, while the low-velocity enhancement is induced from a dynamical confinement of the ion level inside the band gap, the high-velocity enhancement is due to electron recapture from transiently populated image states. Results are presented for Li(110), Cu(111), and Pd(111) surfaces.

Schmitz, Andrew; Shaw, John; Chakraborty, Himadri S. [Center for Innovation and Entrepreneurship, Department of Chemistry and Physics, Northwest Missouri State University, Maryville, Missouri 64468 (United States); Thumm, Uwe [Department of Physics and Astronomy, Kansas State University, Manhattan, Kansas 66502 (United States)

2010-04-15

19

Manipulation of dietary cation-anion difference on nutritionally related production diseases, productivity, and metabolic responses of dairy cows.  

PubMed

Dietary cation-anion difference has been defined as milliequivalents of (Na+K)-(Cl+S) per kilogram of DM and has a direct impact on blood acid-base metabolism. As this difference decreases, one or more of the following blood parameters change: increased H+, decreased HCO3-, and decreased pH. These changes are accompanied by reduced urinary HCO3- excretion and pH as compensatory mechanisms. Although other minerals have an impact on acid-base metabolism, the four minerals used in dietary cation-anion difference have the greatest effect. Manipulation of acid-base balance can be used to manipulate other biological functions to benefit health and productivity of cows. Low cation-anion difference prepartum can mitigate hypocalcemia peripartum via increased urinary Ca, blood-ionized Ca, and responsiveness to Ca homeostatic hormones. These changes reduced the incidence of paresis and increased productivity by reducing the severity and length of hypocalcemia in all cows (periparturient), regardless of the occurrence of paresis. Reduced cation-anion differences prepartum have been related to a reduced severity of udder edema, likely related to increased renal loss of water and unchanged water intake. However, the effects on acid-base balance cannot be ruled out because of effects on biochemical and transport processes. Elevated cation-anion difference in lactation has been shown to increase DMI and production and to mitigate the effects of heat stress. Because production and heat stress are acidogenic, elevated cation-anion difference improves blood-buffering capacity to cope with H+. In heat stress, elevated water intake with elevated cation-anion difference cannot be ignored. Other diseases related to metabolic acid, such as laminitis and ketoacidosis, may be influenced by elevated cation-anion difference in lactation; however, research in these areas has not been forthcoming. PMID:8046083

Block, E

1994-05-01

20

Manipulation of Dietary Cation-Anion Difference on Nutritionally Related Production Diseases, Productivity, and Metabolic Responses of Dairy Cows1  

Microsoft Academic Search

ABSTRACT Dietary cation-anion difference has been defined as milliequivalents of (Na + K) - (Cl + S) per kilogram,of DM and has a direct impact on blood acid-base metabolism. As this difference decreases, one,or more,of the following,blood parameters change: increased H+, decreased HCO;, and decreased pH. These,changes,are,accompanied,by reduced urinary HCO; excretion and pH as compensatory,mechanisms.,Although other minerals have an impact

Elliot Block

1994-01-01

21

Metabolic costs of changing the cation-anion difference in the diet of juvenile African catfish Clarias gariepinus (Burchell)  

Microsoft Academic Search

The influence of dietary cation-anion difference (CAD, Na K - Cl, mEq kg1) on energy metabolism and nitrogen losses in juvenile African catfish Clarias gariepinus (Burchell) was examined in fish exposed to different dietary CAD levels (-146, 116, 497, 713 and 828 mEq kg1 diet). The experiment was conducted in open circuit balance respiration chambers over a 3-week period. Five

Y. Dersjant-Li; J. A. J. Verreth; P. A. T. Tijssen; R. Booms; M. W. A. Verstegen; E. A. Huisman

2000-01-01

22

The relationship between dietary cation-anion difference and nitrogen metabolism in lactating dairy cows.  

E-print Network

??Positive dietary cation-anion difference (DCAD) enhances blood bicarbonate concentrations in lactating cows, improving blood buffering which may improve animal health and performance. The objectives of… (more)

Wildman, Christopher Dwayne

2005-01-01

23

Linkage of organic anion transporter-1 to metabolic pathways through integrated "omics"-driven network and functional analysis.  

PubMed

The main kidney transporter of many commonly prescribed drugs (e.g. penicillins, diuretics, antivirals, methotrexate, and non-steroidal anti-inflammatory drugs) is organic anion transporter-1 (OAT1), originally identified as NKT (Lopez-Nieto, C. E., You, G., Bush, K. T., Barros, E. J., Beier, D. R., and Nigam, S. K. (1997) J. Biol. Chem. 272, 6471-6478). Targeted metabolomics in knockouts have shown that OAT1 mediates the secretion or reabsorption of many important metabolites, including intermediates in carbohydrate, fatty acid, and amino acid metabolism. This observation raises the possibility that OAT1 helps regulate broader metabolic activities. We therefore examined the potential roles of OAT1 in metabolic pathways using Recon 1, a functionally tested genome-scale reconstruction of human metabolism. A computational approach was used to analyze in vivo metabolomic as well as transcriptomic data from wild-type and OAT1 knock-out animals, resulting in the implication of several metabolic pathways, including the citric acid cycle, polyamine, and fatty acid metabolism. Validation by in vitro and ex vivo analysis using Xenopus oocyte, cell culture, and kidney tissue assays demonstrated interactions between OAT1 and key intermediates in these metabolic pathways, including previously unknown substrates, such as polyamines (e.g. spermine and spermidine). A genome-scale metabolic network reconstruction generated some experimentally supported predictions for metabolic pathways linked to OAT1-related transport. The data support the possibility that the SLC22 and other families of transporters, known to be expressed in many tissues and primarily known for drug and toxin clearance, are integral to a number of endogenous pathways and may be involved in a larger remote sensing and signaling system (Ahn, S. Y., and Nigam, S. K. (2009) Mol. Pharmacol. 76, 481-490, and Wu, W., Dnyanmote, A. V., and Nigam, S. K. (2011) Mol. Pharmacol. 79, 795-805). Drugs may alter metabolism by competing for OAT1 binding of metabolites. PMID:21757732

Ahn, Sun-Young; Jamshidi, Neema; Mo, Monica L; Wu, Wei; Eraly, Satish A; Dnyanmote, Ankur; Bush, Kevin T; Gallegos, Tom F; Sweet, Douglas H; Palsson, Bernhard Ø; Nigam, Sanjay K

2011-09-01

24

Mineral metabolism in plasma, urine and bone of periparturient cows fed anionic diets with different calcium and phosphorous contents.  

PubMed

The objective of this experiment was to evaluate the influences of Ca and P contents in an anionic diet on the mineral metabolism in plasma, urine and bone in periparturient diary cows. Fifteen multiparous Holstein-Friesian cows were divided into 3 dietary groups (5 cows/group) by dietary Ca and P contents and dietary cation-anion balance [(Na + K) - (Cl + S) mEq/kg DM]; diet 1 [low Ca (0.46%), low P (0.24%), cationic (+195.8 mEq/kg DM)]; diet 2 [low Ca (0.46%), low P (0.24%), anionic (-32.4 mEq/kg DM)]; and diet 3 [high Ca (0.93%), high P (0.60%), anionic (-41.0 mEq/kg DM)]. Cows were fed one of these 3 diets from approximately 4 weeks before the expected calving date to 5 days after calving. There was no outbreak of milk fever in any cows fed these 3 diets; however, plasma Ca levels at 1 and 2 days after calving tended to be higher in the cows fed diet 3 than those in the cows fed diets 1 or 2. Fractional urinary excretion of Ca in the cows fed diet 2 or 3 was higher than that in the cows fed diet 1. Fractional urinary excretion and plasma level of Pi were higher during the periparturient period in the cows fed diet 3 than those in the cows fed diets 1 or 2. There were no significant differences in plasma parathyroid hormone levels among the 3 groups. In the spongy substance of ilium at 5 days after calving, the Ca and Mg contents bone volume and trabecular thickness were the lowest, but not significant, in the cows fed diet 2. These data suggest that sufficient Ca and P contents in an anionic diet may be effective in maintaining plasma Ca and Pi levels of periparturient cows and further in preventing of potential bone damage brought about by increased urinary mineral excretion following the feeding of an anionic diet. PMID:8996701

Won, J H; Oishi, N; Kawamura, T; Sugiwaka, T; Fukuda, S; Sato, R; Naito, Y

1996-12-01

25

Likelihood-based gene annotations for gap filling and quality assessment in genome-scale metabolic models.  

PubMed

Genome-scale metabolic models provide a powerful means to harness information from genomes to deepen biological insights. With exponentially increasing sequencing capacity, there is an enormous need for automated reconstruction techniques that can provide more accurate models in a short time frame. Current methods for automated metabolic network reconstruction rely on gene and reaction annotations to build draft metabolic networks and algorithms to fill gaps in these networks. However, automated reconstruction is hampered by database inconsistencies, incorrect annotations, and gap filling largely without considering genomic information. Here we develop an approach for applying genomic information to predict alternative functions for genes and estimate their likelihoods from sequence homology. We show that computed likelihood values were significantly higher for annotations found in manually curated metabolic networks than those that were not. We then apply these alternative functional predictions to estimate reaction likelihoods, which are used in a new gap filling approach called likelihood-based gap filling to predict more genomically consistent solutions. To validate the likelihood-based gap filling approach, we applied it to models where essential pathways were removed, finding that likelihood-based gap filling identified more biologically relevant solutions than parsimony-based gap filling approaches. We also demonstrate that models gap filled using likelihood-based gap filling provide greater coverage and genomic consistency with metabolic gene functions compared to parsimony-based approaches. Interestingly, despite these findings, we found that likelihoods did not significantly affect consistency of gap filled models with Biolog and knockout lethality data. This indicates that the phenotype data alone cannot necessarily be used to discriminate between alternative solutions for gap filling and therefore, that the use of other information is necessary to obtain a more accurate network. All described workflows are implemented as part of the DOE Systems Biology Knowledgebase (KBase) and are publicly available via API or command-line web interface. PMID:25329157

Benedict, Matthew N; Mundy, Michael B; Henry, Christopher S; Chia, Nicholas; Price, Nathan D

2014-10-01

26

Acid-base status, renal function, water, and macromineral metabolism of dry cows fed diets differing in cation-anion difference.  

PubMed

Dietary cation-anion difference was defined as the summation of the milliequivalents of Na and K minus the sum of the milliequivalents of Cl and S per kilogram of DM. Twelve Holstein cows were used in a crossover experiment to compare the effects of changing the cation-anion difference of a diet based on haylage. Two cation-anion differences, 481.8 and 327.2 meq/kg, were compared. Increased dietary cation-anion difference had no significant effects on BW or intake and digestibility of DM, ADF, NDF, and N. The diet with a cation-anion difference of 481 meq/kg of DM increased apparent absorption of water and urine volume. Fecal excretion of Na and absorption and urinary excretion of S were increased by a cation-anion difference of 327 meq/kg of DM. Although blood concentrations were unaffected, lower dietary cation-anion difference reduced concentrations of H+ and HCO3- in urine and total urinary excretion of HCO3-. Plasma volume, packed cell volume, glomerular filtration rate, and effective renal plasma flow were unaffected by diet. Small changes in dietary cation-anion differences, even within the positive range, affected acid-base status and water metabolism of dry pregnant cows without affecting renal function or blood volume. PMID:7782516

Delaquis, A M; Block, E

1995-03-01

27

Bridging the gap between gene expression and metabolic phenotype via kinetic models  

PubMed Central

Background Despite the close association between gene expression and metabolism, experimental evidence shows that gene expression levels alone cannot predict metabolic phenotypes, indicating a knowledge gap in our understanding of how these processes are connected. Here, we present a method that integrates transcriptome, fluxome, and metabolome data using kinetic models to create a mechanistic link between gene expression and metabolism. Results We developed a modeling framework to construct kinetic models that connect the transcriptional and metabolic responses of a cell to exogenous perturbations. The framework allowed us to avoid extensive experimental characterization, literature mining, and optimization problems by estimating most model parameters directly from fluxome and transcriptome data. We applied the framework to investigate how gene expression changes led to observed phenotypic alterations of Saccharomyces cerevisiae treated with weak organic acids (i.e., acetate, benzoate, propionate, or sorbate) and the histidine synthesis inhibitor 3-aminotriazole under steady-state conditions. We found that the transcriptional response led to alterations in yeast metabolism that mimicked measured metabolic fluxes and concentration changes. Further analyses generated mechanistic insights of how S. cerevisiae responds to these stresses. In particular, these results suggest that S. cerevisiae uses different regulation strategies for responding to these insults: regulation of two reactions accounted for most of the tolerance to the four weak organic acids, whereas the response to 3-aminotriazole was distributed among multiple reactions. Moreover, we observed that the magnitude of the gene expression changes was not directly correlated with their effect on the ability of S. cerevisiae to grow under these treatments. In addition, we identified another potential mechanism of action of 3-aminotriazole associated with the depletion of tetrahydrofolate. Conclusions Our simulation results show that the modeling framework provided an accurate mechanistic link between gene expression and cellular metabolism. The proposed method allowed us to integrate transcriptome, fluxome, and metabolome data to determine and interpret important features of the physiological response of yeast to stresses. Importantly, given its flexibility and robustness, our approach can be applied to investigate the transcriptional-metabolic response in other cellular systems of medical and industrial relevance. PMID:23875723

2013-01-01

28

Cell metabolic changes of porphyrins and superoxide anions by anthracene and benzo(a)pyrene.  

PubMed

The aim of this work was to evaluate the induction of protoporphyrins IX (PpIX) activity and superoxide anions (SO) in human leukocytes exposed to anthracene (ANT) and benzo(a)pyrene (B(a)P). The leukocyte LC(50)s for both hydrocarbons and the PpIX accumulation and SO overproduction were measured. The LC(50)s were 0.35 and 3.23?M for ANT and B(a)P, respectively. A linear relationship (r=0.97, p<0.01) between PpIX and ANT concentration was obtained. The induced accumulation of PpIX was proportional (r=0.63, p<0.01) to B(a)P concentration. SO overproduction showed a linear relationship (r=0.83, p<0.05) with ANT concentrations. The linear regression analysis of the effect of B(a)P on the superoxide anion overproduction showed a good coefficient (r=0.97, p<0.01), showed that ANT and B(a)P exposure induces PpIX accumulation, probably by disruption of the haem biosynthesis. ANT and B(a)P induce SO overproduction, perhaps through a process of redox cycling. PMID:21791370

Uribe-Hernández, Raúl; Pérez-Zapata, Aura J; Vega-Barrita, María L; Ramón-Gallegos, Eva; Amezcua-Allieri, Myriam A

2008-09-01

29

Effects of altering dietary cation-anion difference on calcium and energy metabolism in peripartum cows.  

PubMed

Our objective was to determine the effects of varying dietary cation-anion differences (DCAD: meq[(Na + K) - (Cl + S)]/100 g of dry matter) in prepartum diets on Ca, energy, and endocrine status prepartum and postpartum. Holstein cows (n = 21) and heifers (n = 34) were fed diets with varying amounts of CaCl2, CaSO4, and MgSO4 to achieve a DCAD of +15 (control), 0, or -15 meq/100 g of dry matter for the last 24 d before expected calving. Dietary Ca concentration was increased (by CaCO3 supplementation) with decreasing DCAD. Plasma ionized Ca concentrations prepartum and at calving in both cows and heifers increased with reduced DCAD in the diet. At calving, plasma ionized Ca concentration was 3.67, 3.85, and 4.35 for cows and 4.44, 4.57, and 4.62 mg/dl for heifers fed diets containing +15, 0, and -15 DCAD, respectively. All heifers had normal concentrations of plasma ionized Ca (>4 mg/dl) at calving. Also at calving, plasma concentrations ofparathyroid hormone and calcitriol were less in cows and heifers fed diets containing reduced DCAD, but the plasma concentration of hydroxyproline was not affected by diet. Prepartum dry matter intake, energy balance, and body weight gains were lower and concentration of liver triglyceride was higher for heifers but not cows fed the -15 DCAD diet. Also, nonesterified fatty acids the last week prepartum were positively correlated with liver triglyceride for heifers but not cows. Feeding of anionic salts plus CaCO3 to reduce DCAD to -15 and increase Ca in prepartum diets prevents hypocalcemia at calving in cows, but decreases prepartum dry matter intake and increases the concentration of liver triglyceride in heifers. That heifers maintained calcium homeostasis at calving regardless of diet but ate less when fed the -15 DCAD diet suggests that they should not be fed anionic salts before calving. PMID:11003243

Moore, S J; VandeHaar, M J; Sharma, B K; Pilbeam, T E; Beede, D K; Bucholtz, H F; Liesman, J S; Horst, R L; Goff, J P

2000-09-01

30

The impact of dietary cation anion difference (DCAD) on the acid-base balance and calcium metabolism of non-lactating, non-pregnant dairy cows fed equal amounts of different anionic salts.  

PubMed

We evaluated the impact of the dietary cation-anion difference (DCAD) on the influence of anionic salts (AS) on the metabolism of dairy cows using a study-design that included control of feed intake. Ten mature, non-lactating, non-pregnant, Holstein-Friesian-crossbreed cows received 2000 mEq of either one of the seven anionic salts tested, two combinations of the anionic salts or water as control via a rumen cannula. Salts and controls were assigned in a 10x10 Latin square design. Whole blood, serum and urine samples were taken during treatment (TP) and washout period. Samples of whole blood were tested for pH, base-excess and bicarbonate concentrations. In urine, pH and net acid-base excretion (NABE) were analysed. Calcium was measured in serum and urine. According to the different batches of hay, five groups of DCAD were created regarding cluster analysis. Changes in urine and blood parameters were statistically analysed for each DCAD group separately. The different DCAD had an impact on the amount of change in acid-base balance (ABB) and calcium metabolism and for how long these changes lasted. In the DCAD group receiving the highest amount of AS (239 mEq/kg dry matter with AS), changes of ABB were only noticeable in urine and these changes only differed from day zero in the first week of TP (P<0.05). In the other four groups changes of ABB were also visible in blood parameters, but only on a few days of TP did the deviations differ significantly (P<0.05) from day zero. Changes of ABB parameters in urine samples were more pronounced than those in blood and differed clearly from day zero (P<0.05). Parallel to the changes of ABB, calcium concentrations in these samples were significantly increased (P<0.001) in all DCAD groups. Except for the highest DCAD group, ionized calcium concentrations changed over time (P<0.020). However, the differences were very small and only differed from day zero on a few TP days. We conclude that the DCAD of a dairy cow's diet has an important impact on the effect of AS on ABB and calcium metabolism with respect to the duration and amount of change. The target regions of DCAD should be clearly below 100 mEq/kg dry matter to ensure the desired effect on ABB and calcium metabolism. Extremely negative DCAD should be avoided to minimize the risk of clinical acidosis induced by AS. PMID:17451620

Gelfert, Carl-Christian; Leonie Loeffler, S; Frömer, Sven; Engel, Maike; Hartmann, Helmut; Männer, Klaus; Baumgartner, Walter; Staufenbiel, Rudolf

2007-08-01

31

Dietary cation-anion difference, acid-base status, mineral metabolism, renal function, and milk production of lactating cows.  

PubMed

Three switchback experiments were conducted with 12 cows in early lactation, 12 cows in midlactation, and 12 cows in late lactation. Each experiment compared two dietary cation-anion differences. Increasing dietary cation-anion difference increased DMI and milk production in early and midlactation. These effects were not observed in late lactation. Production of milk protein and lactose and concentration of lactose were increased by the higher dietary cation-anion difference in early lactation. Higher dietary cation-anion difference reduced milk fat concentration in midlactation because of the higher milk production. In late lactation, none of the milk components were affected by dietary cation-anion difference. In early and midlactation, apparent absorption of water and urine volume were increased by a higher dietary cation-anion difference; these effects were not caused by higher intake of Na or by higher glomerular filtration rate. Intake, balance, and concentration of S in plasma were increased by the lower cation-anion difference at all stages of lactation. Excretion of HCO3- in urine was reduced by a lower dietary cation-anion difference at all stages of lactation, but secretion of protons in milk was reduced in late lactation only. Increasing dietary cation-anion difference does affect acid-base parameters in urine at all stages of lactation, but DMI and milk production of cows were affected in early and midlactation only. PMID:8598410

Delaquis, A M; Block, E

1995-10-01

32

Organic anion-transporting polypeptide 1a4 (Oatp1a4) is important for secondary bile acid metabolism  

PubMed Central

Organic anion transporting polypeptides (human: OATPs; rodent: Oatps) were thought to have important functions in bile acid (BA) transport. Oatp1a1, 1a4, and 1b2 are the three major Oatp1 family members in rodent liver. Our previous studies have characterized the BA homeostasis in Oatp1a1-null and Oatp1b2-null mice. The present study investigated the physiological role of Oatp1a4 in BA homeostasis by using Oatp1a4-null mice. Oatp1a4 expression is female-predominant in livers of mice, and thereby it was expected that female Oatp1a4-null mice will have more prominent changes than males. Interestingly, the present study demonstrated that female Oatp1a4-null mice had no significant alterations in BA concentrations in serum or liver, though they had increased mRNA of hepatic BA efflux transporters (Mrp4 and Ost?/?) and ileal BA transporters (Asbt and Ost?/?). In contrast, male Oatp1a4-null mice showed significantly altered BA homeostasis, including increased concentrations of deoxycholic acid (DCA) in serum, liver and intestinal contents. After feeding a DCA-supplemented diet, male but not female Oatp1a4-null mice had higher concentrations of DCA in serum and livers than their WT controls. This suggested that Oatp1a4 is important for intestinal absorption of secondary BAs in male mice. Furthermore, loss of Oatp1a4 function did not decrease BA accumulation in serum or livers of bile-ductligated mice, suggesting that Oatp1a4 is not likely a BA uptake transporter. In summary, the present study for the first time demonstrates that Oatp1a4 does not appear to mediate the hepatic uptake of BAs, but plays an important male-predominant role in secondary BA metabolism in mice. PMID:23747753

Zhang, Youcai; Csanaky, Iván L.; Selwyn, Felcy Pavithra; Lehman-McKeeman, Lois D.; Klaassen, Curtis D.

2013-01-01

33

Organic anion-transporting polypeptide 1a4 (Oatp1a4) is important for secondary bile acid metabolism.  

PubMed

Organic anion transporting polypeptides (human: OATPs; rodent: Oatps) were thought to have important functions in bile acid (BA) transport. Oatp1a1, 1a4, and 1b2 are the three major Oatp1 family members in rodent liver. Our previous studies have characterized the BA homeostasis in Oatp1a1-null and Oatp1b2-null mice. The present study investigated the physiological role of Oatp1a4 in BA homeostasis by using Oatp1a4-null mice. Oatp1a4 expression is female-predominant in livers of mice, and thereby it was expected that female Oatp1a4-null mice will have more prominent changes than males. Interestingly, the present study demonstrated that female Oatp1a4-null mice had no significant alterations in BA concentrations in serum or liver, though they had increased mRNA of hepatic BA efflux transporters (Mrp4 and Ost?/?) and ileal BA transporters (Asbt and Ost?/?). In contrast, male Oatp1a4-null mice showed significantly altered BA homeostasis, including increased concentrations of deoxycholic acid (DCA) in serum, liver and intestinal contents. After feeding a DCA-supplemented diet, male but not female Oatp1a4-null mice had higher concentrations of DCA in serum and livers than their WT controls. This suggested that Oatp1a4 is important for intestinal absorption of secondary BAs in male mice. Furthermore, loss of Oatp1a4 function did not decrease BA accumulation in serum or livers of bile-duct-ligated mice, suggesting that Oatp1a4 is not likely a BA uptake transporter. In summary, the present study for the first time demonstrates that Oatp1a4 does not appear to mediate the hepatic uptake of BAs, but plays an important male-predominant role in secondary BA metabolism in mice. PMID:23747753

Zhang, Youcai; Csanaky, Iván L; Selwyn, Felcy Pavithra; Lehman-McKeeman, Lois D; Klaassen, Curtis D

2013-08-01

34

Solving gap metabolites and blocked reactions in genome-scale models: application to the metabolic network of Blattabacterium cuenoti  

PubMed Central

Background Metabolic reconstruction is the computational-based process that aims to elucidate the network of metabolites interconnected through reactions catalyzed by activities assigned to one or more genes. Reconstructed models may contain inconsistencies that appear as gap metabolites and blocked reactions. Although automatic methods for solving this problem have been previously developed, there are many situations where manual curation is still needed. Results We introduce a general definition of gap metabolite that allows its detection in a straightforward manner. Moreover, a method for the detection of Unconnected Modules, defined as isolated sets of blocked reactions connected through gap metabolites, is proposed. The method has been successfully applied to the curation of iCG238, the genome-scale metabolic model for the bacterium Blattabacterium cuenoti, obligate endosymbiont of cockroaches. Conclusion We found the proposed approach to be a valuable tool for the curation of genome-scale metabolic models. The outcome of its application to the genome-scale model B. cuenoti iCG238 is a more accurate model version named as B. cuenoti iMP240. PMID:24176055

2013-01-01

35

Spectroscopy of the low-lying states of the group III-V diatomics, AlP, GaP, InP, and GaAs via anion photodetachment spectroscopy  

NASA Astrophysics Data System (ADS)

The low-lying electronic states of AlP, GaP, InP, and GaAs have been probed using anion photoelectron spectroscopy and zero electronic kinetic energy spectroscopy. We observe transitions from the anion 2Sigma+ and low-lying 2Pi states to the triplet (3Sigma- and 3Pi states) and singlet (1Pi, 1Sigma+, and 1Delta states) manifolds of the neutral species. The spectra of the triplet manifolds are particularly complex, with overlapping spin-orbit and vibrational progressions. Spin-orbit splittings, term energies, and vibrational frequencies are reported and compared to previous electronic structure calculations on the anions and neutrals, as well as to those parameters determined previously for the isovalent homonuclear diatomics Si2, Ge2, and Sn2.

Gomez, Harry; Taylor, Travis R.; Zhao, Yuexing; Neumark, Daniel M.

2002-11-01

36

METABOLIC RESPONSES OF TRANSITION HOLSTEIN COWS FED ANIONIC SALTS AND SUPPLEMENTED AT CALVING WITH CALCIUM AND ENERGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), and glucose in transition cows fed anionic salts prepartum and provided with calcium and energy supplements at calving. The study was conducted on a Fl...

37

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability  

PubMed Central

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function. PMID:20698033

Yang, Yoon Mee; Han, Chang Yeob; Kim, Yoon Jun; Kim, Sang Geon

2010-01-01

38

Effects of Altering Dietary Cation-Anion Difference on Calcium and Energy Metabolism in Peripartum Cows1  

Microsoft Academic Search

Our objective was to determine the effects of varying dietary cation-anion differences (DCAD: meq((Na + K) ? (Cl + S))\\/100 g of dry matter) in prepartum diets on Ca, energy, and endocrine status prepartum and postpartum. Holstein cows (n = 21) and heifers (n = 34) were fed diets with varying amounts of CaCl2, CaSO4, and MgSO4 to achieve a

S. J. Moore; M. J. VandeHaar; B. K. Sharma; T. E. Pilbeam; D. K. Beede; H. F. Bucholtz; J. S. Liesman; R. L. Horst; J. P. Goff

2000-01-01

39

Effects of dietary cation–anion difference on calcium, nitrogen metabolism and relative blood traits of dry Holstein cows  

Microsoft Academic Search

Three multiparous nonpregnant dry Holstein cows were designated in a 3×3 Latin square experiment to investigate the effects of dietary DCAD level on Ca, N metabolism, and relative blood traits. DCAD levels of the three experimental diets were 224 (HDCAD), 151 (MDCAD), and ?265 (LDCAD) mequiv.\\/kg DM respectively. The results indicated that deposition efficiencies of absorbed Ca and digestible N

F. C. Li; H. F. Liu; Z. H. Wang

2008-01-01

40

The barley anion channel, HvALMT1, has multiple roles in guard cell physiology and grain metabolism.  

PubMed

The barley (Hordeum vulgare) gene HvALMT1 encodes an anion channel in guard cells and in certain root tissues indicating that it may perform multiple roles. The protein localizes to the plasma membrane and facilitates malate efflux from cells when constitutively expressed in barley plants and Xenopus oocytes. This study investigated the function of HvALMT1 further by identifying its tissue-specific expression and by generating and characterizing RNAi lines with reduced HvALMT1 expression. We show that transgenic plants with 18-30% of wild-type HvALMT1 expression had impaired guard cell function. They maintained higher stomatal conductance in low light intensity and lost water more rapidly from excised leaves than the null segregant control plants. Tissue-specific expression of HvALMT1 was investigated in developing grain and during germination using transgenic barley lines expressing the green fluorescent protein (GFP) with the HvALMT1 promoter. We found that HvALMT1 is expressed in the nucellar projection, the aleurone layer and the scutellum of developing barley grain. Malate release measured from isolated aleurone layers prepared from imbibed grain was significantly lower in the RNAi barley plants compared with control plants. These data provide molecular and physiological evidence that HvALMT1 functions in guard cells, in grain development and during germination. We propose that HvALMT1 releases malate and perhaps other anions from guard cells to promote stomatal closure. The likely roles of HvALMT1 during seed development and grain germination are also discussed. PMID:24853664

Xu, Muyun; Gruber, Benjamin D; Delhaize, Emmanuel; White, Rosemary G; James, Richard A; You, Jiangfeng; Yang, Zhenming; Ryan, Peter R

2015-01-01

41

Bridging the gap: Membrane contact sites in signaling, metabolism, and organelle dynamics  

PubMed Central

Regions of close apposition between two organelles, often referred to as membrane contact sites (MCSs), mostly form between the endoplasmic reticulum and a second organelle, although contacts between mitochondria and other organelles have also begun to be characterized. Although these contact sites have been noted since cells first began to be visualized with electron microscopy, the functions of most of these domains long remained unclear. The last few years have witnessed a dramatic increase in our understanding of MCSs, revealing the critical roles they play in intracellular signaling, metabolism, the trafficking of metabolites, and organelle inheritance, division, and transport. PMID:24958771

2014-01-01

42

Effects of anionic salts supplementation on blood pH and mineral status, energy metabolism, reproduction and production in transition dairy cows.  

PubMed

The objectives of this study were to determine the effects of a pre-partum diet with lower than recommended (DCAD=-82 mEq/kg of dietary DM) amounts of anionic salts on metabolism, health, reproductive performance and milk production in dairy cows. Sixty Holstein multiparous cows were enrolled 21 days prior to expected calving date. The animals were randomly assigned to receive one of two rations: 30 cows received anionic ration [-82 mEq (NA+K-Cl-S)/kg of DM] for 21 d to parturition and the other group (n=30) were fed a usual dry period ration (+192 mEq/kg of DM). Serum samples obtained at days -21, +3 and +21 relative to calving were analyzed for beta-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFA), glucose, calcium (Ca), inorganic phosphorus, magnesium, chloride, sodium, potassium, cholesterol, urea, creatinine, total protein, albumin, and aspartate aminotransferase (AST). Urine pH declined from 8.4 at 21 d before calving (pre-treatment) to 6.2 at day 7 pre-partum in the treatment group. Repeated-measure mixed model analysis indicated that the concentrations of Ca were significantly increased and creatinine, and AST were significantly decreased by lowering DCAD. The concentrations of BHBA, NEFA and glucose were not affected by treatment. The incidence of milk fever and culling were 5 and 11 times higher in the control group in comparison with the treatment group, respectively. The intervals from calving to first breeding and to pregnancy were not influenced by treatment. There was no group effect on average daily milk yield or fat percentage. PMID:20153494

Seifi, Hesam A; Mohri, Mehrdad; Farzaneh, Nima; Nemati, Hadi; Nejhad, Shima Vahidi

2010-08-01

43

Dysfunction of Organic Anion Transporting Polypeptide 1a1 Alters Intestinal Bacteria and Bile Acid Metabolism in Mice  

PubMed Central

Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

Zhang, Youcai; Limaye, Pallavi B.; Lehman-McKeeman, Lois D.; Klaassen, Curtis D.

2012-01-01

44

Aspirin and probenecid inhibit organic anion transporter 3-mediated renal uptake of cilostazol and probenecid induces metabolism of cilostazol in the rat.  

PubMed

This study aimed to evaluate the transporter-mediated renal excretion mechanism for cilostazol and to characterize the mechanism of drug-drug interaction (DDI) between cilostazol and aspirin or probenecid. Concentrations of cilostazol and its metabolites OPC-13015 [6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-2(1H)-quinolinone] and OPC-13213 [3,4-dihydro-6-[4-[1-(trans-4-hydroxycyclohexyl)-1H-tetrazol-5-yl]butoxy]-2-(1H)-quinolinone] in rat biologic or cell samples were measured by liquid chromatography-tandem mass spectrometry. Coadministration with probenecid, benzylpenicillin, or aspirin decreased the cumulative urinary excretion of cilostazol and renal clearance. Concentrations of cilostazol and OPC-13213 in plasma decreased, and the concentration of OPC-13015 increased in the presence of probenecid. By contrast, rat plasma cilostazol, in combination with benzylpenicillin or aspirin, sharply increased, and concentrations of OPC-13015 and OPC-13213 did not change. In urine, OPC-13015 was below the level of detection. The cumulative urinary excretion of OPC-13213 decreased in the presence of probenecid, benzylpenicillin, or aspirin. Cilostazol was distributed in the kidney and liver, with tissue to plasma partition coefficient (Kp) values of 8.4 ml/g and 16.3 ml/g, respectively. Probenecid and aspirin reduced cilostazol distribution in the kidney. Probenecid did not affect cilostazol metabolism in the kidney but increased cilostazol metabolism in the liver, and aspirin had no effect on cilostazol metabolism. Benzylpenicillin, aspirin, and cyclo-trans-4-l-hydroxyprolyl-l-serine (JBP485) reduced cilostazol uptake in kidney slices and human organic anion transporter 3 (hOAT3)-human embryonic kidney 293 (HEK293) cells, whereas p-aminohippuric acid did not. Compared with the vector, hOAT3-HEK293 cells accumulated more cilostazol, whereas hOAT1-HEK293 cells did not. OAT3 and Oat3 play a major role in cilostazol renal excretion, whereas OAT1 and Oat1 do not. Oat3 and Cyp3a are both targets of the DDI between cilostazol and probenecid. Aspirin inhibits OAT3-mediated uptake of cilostazol and does not influence cilostazol metabolism. PMID:24692216

Wang, Chong; Wang, Changyuan; Liu, Qi; Meng, Qiang; Cang, Jian; Sun, Huijun; Peng, Jinyong; Ma, Xiaochi; Huo, Xiaokui; Liu, Kexin

2014-06-01

45

Metabolism  

MedlinePLUS

Metabolism refers to all the physical and chemical processes in the body that convert or use energy, ... Tortora GJ, Derrickson BH. Metabolism. In: Tortora GJ, Derrickson BH. Principles of Anatomy and Physiology . 14th ed. Hoboken, NJ: John H Wiley and Sons; 2013: ...

46

Comparison of the impact of different anionic salts on the acid–base status and calcium metabolism in non-lactating, non-pregnant dairy cows  

Microsoft Academic Search

Eleven mature, non-lactating, non-pregnant, Holstein–Friesian crossbred cows were given, via a ruminal cannula, 2000mEq of one of three chloride salts, four sulfate salts, two combinations of anionic salts (AS), sodium chloride (as neutral salt), or water as control. The salts and controls were assigned in an 11×11 Latin square and the cows were randomly distributed.All of the AS induced a

C.-C. Gelfert; L. M. Loeffler; S. Frömer; M. Engel; K. Männer; R. Staufenbiel

2010-01-01

47

(-)-Epicatechin prevents alterations in the metabolism of superoxide anion and nitric oxide in the hearts of l-NAME-treated rats.  

PubMed

The aim of this work was to evaluate the effects of (-)-epicatechin administration in the heart of a rat model with reduced NO production that follows a short-term treatment with l-NAME. Sprague-Dawley rats were treated for 4 d with l-NAME in the absence or presence of (-)-epicatechin in the diet. The redox status in cardiac tissue was improved by (-)-epicatechin administration. l-NAME treatment induced a decrease in NO synthase activity (-62%, p < 0.05) and an increase in NADPH-dependent superoxide anion production (+300%, p < 0.05) that were totally prevented by (-)-epicatechin administration. These effects of (-)-epicatechin were associated with a higher endothelial NO synthase phosphorylation at an activation site and a reduced expression of the regulatory subunit, p47(phox), suggesting the involvement of posttranslational mechanisms in (-)-epicatechin action. Thus, the (-)-epicatechin treatment would restore NO steady state levels in vivo through effects on both, its synthesis and degradation via the reaction with superoxide anion. The fact that (-)-epicatechin is commonly present in human diet makes this compound a reasonable explanation for the positive cardiovascular effects of a high consumption of fruits and vegetables. PMID:25361437

Piotrkowski, Barbara; Calabró, Valeria; Galleano, Mónica; Fraga, César G

2015-01-24

48

Profound metabolic acidosis and oxoprolinuria in an adult  

Microsoft Academic Search

Introduction  Profound metabolic acidosis in critically ill adults sometimes remains unexplained despite extensive evaluation.\\u000a \\u000a \\u000a \\u000a Case Report  A 58-year-old female presented in a confused state to the emergency department; she had been confused for several days. Laboratory\\u000a evaluation revealed a high anion gap metabolic acidosis and modestly elevated acetaminophen level. Lactic acid was only modestly\\u000a elevated. There was no evidence of ketoacids, salicylate,

Michael J. Hodgman; James F. Horn; Christine M. Stork; Jeanna M. Marraffa; Michael G. Holland; Richard Cantor; Patti M. Carmel

2007-01-01

49

Filling Knowledge Gaps in Biological Networks: integrating global approaches to understand H2 metabolism in Chlamydomonas reinhardtii - Final Report  

SciTech Connect

The green alga Chlamydomonas reinhardtii (Chlamydomonas) has numerous genes encoding enzymes that function in fermentative pathways. Among these genes, are the [FeFe]-hydrogenases, pyruvate formate lyase, pyruvate ferredoxin oxidoreductase, acetate kinase, and phosphotransacetylase. We have systematically undertaken a series of targeted mutagenesis approaches to disrupt each of these key genes and �¢����omics�¢���� techniques to characterize alterations in metabolic flux. Funds from DE-FG02-07ER64423 were specifically leveraged to generate mutants with disruptions in the genes encoding the [FeFe]-hydrogenases HYDA1 and HYDA2, pyruvate formate lyase (PFL1), and in bifunctional alcohol/aldehyde alcohol dehydrogenase (ADH1). Additionally funds were used to conduct global transcript profiling experiments of wildtype Chlamydomonas cells, as well as of the hydEF-1 mutant, which is unable to make H2 due to a lesion in the [FeFe]-hydrogenase biosynthetic pathway. In the wildtype cells, formate, acetate and ethanol are the dominant fermentation products with traces of CO2 and H2 also being produced. In the hydEF-1 mutant, succinate production is increased to offset the loss of protons as a terminal electron acceptor. In the pfl-1 mutant, lactate offsets the loss of formate production, and in the adh1-1 mutant glycerol is made instead of ethanol. To further probe the system, we generated a double mutant (pfl1-1 adh1) that is unable to synthesize both formate and ethanol. This strain, like the pfl1 mutants, secreted lactate, but also exhibited a significant increase in the levels of extracellular glycerol, acetate, and intracellular reduced sugars, and a decline in dark, fermentative H2 production. Whereas wild-type Chlamydomonas fermentation primarily produces formate and ethanol, the double mutant performs a complete rerouting of the glycolytic carbon to lactate and glycerol. Lastly, transcriptome data have been analysed for both the wildtype and hydEF-1, that correlate with our observed fermentative metabolites. Intriguingly, over half of the most differentially regulated genes are of unknown function.

Posewitz, Matthew C

2011-06-30

50

Factors influencing the formation of the carbon dioxide radical anion (.CO2-) spin adduct of PBN in the rat liver metabolism of halocarbons.  

PubMed

Spin trapping techniques have been used to detect free radicals generated from the in vitro metabolism by rat liver microsomes of carbon tetrachloride (CCl4) and bromotrichloromethane (BrCCl3) under conditions of varying oxygen tension and pH. Dispersions of rat liver microsomes incubated with 12CCl4, 13CCl4 or Br12CCl3, alpha-phenyl-tert-butyl nitrone (PBN) and NADPH/NADH in a phosphate buffer varying in pH from 6.6 to 8.0 under varying oxygen tensions produced various amounts of four different PBN adducts: PBN-CCl3, PBN-L, PBN-OL and PBN-CO2- where L is a carbon-centered lipid type radical and LO is an oxygen-centered lipid type radical. The relative amount of PBN-CO2- increases with the absence of oxygen. With the use of 31P-NMR in vivo spectroscopy it was possible to detect a pH change from 7.4 to 6.8 in the livers of rats treated with CCl4 or BrCCl3. These results suggest that halocarbon metabolism in biological systems may depend on both oxygen tension as well as pH. PMID:2854105

Janzen, E G; Towner, R A; Brauer, M

1988-01-01

51

Quantum Chemical Approach to Estimating the Thermodynamics of Metabolic Reactions  

NASA Astrophysics Data System (ADS)

Thermodynamics plays an increasingly important role in modeling and engineering metabolism. We present the first nonempirical computational method for estimating standard Gibbs reaction energies of metabolic reactions based on quantum chemistry, which can help fill in the gaps in the existing thermodynamic data. When applied to a test set of reactions from core metabolism, the quantum chemical approach is comparable in accuracy to group contribution methods for isomerization and group transfer reactions and for reactions not including multiply charged anions. The errors in standard Gibbs reaction energy estimates are correlated with the charges of the participating molecules. The quantum chemical approach is amenable to systematic improvements and holds potential for providing thermodynamic data for all of metabolism.

Jinich, Adrian; Rappoport, Dmitrij; Dunn, Ian; Sanchez-Lengeling, Benjamin; Olivares-Amaya, Roberto; Noor, Elad; Even, Arren Bar; Aspuru-Guzik, Alán

2014-11-01

52

Quantum chemical approach to estimating the thermodynamics of metabolic reactions.  

PubMed

Thermodynamics plays an increasingly important role in modeling and engineering metabolism. We present the first nonempirical computational method for estimating standard Gibbs reaction energies of metabolic reactions based on quantum chemistry, which can help fill in the gaps in the existing thermodynamic data. When applied to a test set of reactions from core metabolism, the quantum chemical approach is comparable in accuracy to group contribution methods for isomerization and group transfer reactions and for reactions not including multiply charged anions. The errors in standard Gibbs reaction energy estimates are correlated with the charges of the participating molecules. The quantum chemical approach is amenable to systematic improvements and holds potential for providing thermodynamic data for all of metabolism. PMID:25387603

Jinich, Adrian; Rappoport, Dmitrij; Dunn, Ian; Sanchez-Lengeling, Benjamin; Olivares-Amaya, Roberto; Noor, Elad; Even, Arren Bar; Aspuru-Guzik, Alán

2014-01-01

53

Anion exchange membrane  

DOEpatents

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07

54

Anion-controlled foldamers.  

PubMed

This tutorial review provides a summary of anion-mediated folding of linear and cyclic oligomers as well as anion-responsive behaviours of related polymeric architectures. Anions have emerged as a significant focus of the supramolecular community and here we review their impact on directing the secondary structures of synthetic oligomers and polymers while modulating physical properties e.g. molecular recognition. Oligomers and polymers responsive to anionic guests are typically constructed with hydrogen bond donors complementary to the target anions. Anion binding within the cavities leads to folding and helical wrapping of linear and cyclic oligomers as well as control over macromolecular properties of polymers. This review covers the impact of anion binding on guiding the secondary structures of single-stranded folded oligomers (foldamers) and cyclic oligomers (macrocycles), and on modulating the physical properties of select polymer architectures. PMID:20730154

Juwarker, Hemraj; Jeong, Kyu-Sung

2010-10-01

55

A Case of Chronic Ethylene Glycol Intoxication Presenting without Classic Metabolic Derangements  

PubMed Central

Acute ethylene glycol ingestion classically presents with high anion gap acidosis, elevated osmolar gap, altered mental status, and acute renal failure. However, chronic ingestion of ethylene glycol is a challenging diagnosis that can present as acute kidney injury with subtle physical findings and without the classic metabolic derangements. We present a case of chronic ethylene glycol ingestion in a patient who presented with acute kidney injury and repeated denials of an exposure history. Kidney biopsy was critical to the elucidation of the cause of his worsening renal function. PMID:25215251

Toth-Manikowski, Stephanie M.; Menn-Josephy, Hanni

2014-01-01

56

Hemolytic Anemia and Metabolic Acidosis: Think about Glutathione Synthetase Deficiency.  

PubMed

Glutathione synthetase deficiency (GSSD) is a rare disorder of glutathione metabolism with varying clinical severity. Patients may present with hemolytic anemia alone or together with acidosis and central nervous system impairment. Diagnosis is made by clinical presentation and detection of elevated concentrations of 5-oxoproline in urine and low glutathione synthetase activity in erythrocytes or cultured skin fibroblasts. The prognosis seems to depend on early diagnosis and treatment. We report a 4 months old Tunisian male infant who presented with severe metabolic acidosis with high anion gap and hemolytic anemia. High level of 5-oxoproline was detected in her urine and diagnosis of GSSD was made. Treatment consists of the correction of acidosis, blood transfusion, and supplementation with antioxidants. He died of severe metabolic acidosis and sepsis at the age of 15 months. PMID:25166299

Ameur, Salma Ben; Aloulou, Hajer; Nasrallah, Fehmi; Kamoun, Thouraya; Kaabachi, Naziha; Hachicha, Mongia

2015-02-01

57

Anion solvation in alcohols  

SciTech Connect

Anion solvation is measured in alcohols using pump-probe pulse radiolysis and the activation energy of solvation is determined. Solvation of an anion appears to be different than excited state solvation. The continuum dielectric model does not appear to explain the results.

Jonah, C.D.; Xujia, Zhang; Lin, Yi

1996-03-01

58

Ethyl anion preferred conformation  

NASA Astrophysics Data System (ADS)

Ab initio architecture and torsional barrier for ethyl anion, C2H -5 are analyzed using natural bond orbital methodology. The B3LYP/6-311++G(3df,2p) 2-kcal/mol torsional barrier between the preferred staggered and higher-energy eclipsed conformer is calculated to be one-third lower than for ethane. This decrease is largely attributed to reduced hyperconjugative stabilization of the equilibrium anion conformer compared to that for ethane. Proton removal is also predicted to cause opening of the ethane central CCH angle by 7°, attributed to decreased steric repulsion and to increased hyperconjugative stabilization accompanying angle widening in the ion.

Goodman, Lionel; Sauers, Ronald R.

59

Abnormalities of colonic mucin secretion and metabolic changes after internal urinary diversion for bladder exstrophy. A prospective study.  

PubMed

Ten patients with different types of internal urinary diversion for bladder exstrophy were studied prospectively in order to assess metabolic abnormalities and morphological, histochemical and lectin binding changes in the colorectal mucosa. The histochemical and/or lectin binding changes which were found in the majority of patients were identical to those observed in premalignant and malignant conditions of the colon. In some cases they were detectable 3 years after the initial examination but were completely absent from the colorectal mucosa of normal subjects. Metabolic disturbances (metabolic acidosis, increased anion gap, hyperchloraemia) were observed in a substantial number of asymptomatic patients. These findings stress the need for regular endoscopic, histological and metabolic follow-up in these patients and for life-long treatment with bicarbonate or citrate. PMID:2039917

Marcheggiano, A; Iannoni, C; Latella, G; Frieri, G; Diosi, D; De Dominicis, C; Laurenti, C; Caprilli, R

1991-05-01

60

Gap Junctions  

PubMed Central

Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

2013-01-01

61

Metabolic acidosis mimicking diabetic ketoacidosis after use of calorie-free mineral water.  

PubMed

A previously healthy boy was admitted with fever, tachycardia, dyspnea, and was vomiting. A blood test showed a severe metabolic acidosis with pH 7.08 and an anion gap of 36 mmol/L. His urine had an odor of acetone. The serum glucose was 5.6 mmol/L, and no glucosuria was found. Diabetic ketoacidosis could therefore be eliminated. Lactate level was normal. Tests for the most common metabolic diseases were negative. Because of herpes stomatitis, the boy had lost appetite and only been drinking Diet Coke and water the last days. Diet Coke or Coca-Cola Light is sweetened with a blend containing cyclamates, aspartame, and acesulfame potassium, all free of calories. The etiology of the metabolic acidosis appeared to be a catabolic situation exaggerated by fasting with no intake of calories. The elevated anion gap was due to a severe starvation ketoacidosis, mimicking a diabetic ketoacidosis. Pediatricians should recommend carbohydrate/calorie-containing fluids for rehydration of children with acute fever, diarrhea, or illness. PMID:22457081

Dahl, Gry T; Woldseth, Berit; Lindemann, Rolf

2012-09-01

62

Effect of anionic salts in prepartum diets based on alfalfa.  

PubMed

This study compared prepartum diets based on grass, alfalfa, or alfalfa and anionic salts to investigate their effect on Ca metabolism, acid-base status, endocrine response, disease incidence, and lactational performance of periparturient dairy cows. Forty-five nonlactating Holstein cows in their last 3 wk of gestation were fed a control diet based on grass hay with a dietary cation-anion difference [expressed as milli-equivalents of ((Na + K) - (Cl + S))/100 g of dietary dry matter] of +30 or diets based on alfalfa with a dietary cation-anion difference of either +35 or -7. Cows fed the diet with the dietary cation-anion difference of -7 had the lowest urine pH prepartum and had the highest concentrations of ionized Ca in blood and total Ca in serum at parturition. Increases in 1,25-(OH)2 vitamin D per unit decrease in total Ca in serum were greatest for cows fed the diet with a dietary cation-anion difference of -7. Also, cows fed this same diet consumed the most dry matter postpartum. Incidences of health disorders were 13% (10 of 75), 12% (9 of 75), and 5% (4 of 75) for cows fed the diets with dietary cation-anion differences of +30, +35, and -7, respectively. Results indicate that alfalfa, when supplemented with anionic salts, is a viable forage for prepartum dairy cows. PMID:9406079

Joyce, P W; Sanchez, W K; Goff, J P

1997-11-01

63

Formation of interstellar anions  

NASA Astrophysics Data System (ADS)

Formation of interstellar anions: M.L. Senent. The recent detection of negative charged species in the ISM1 has instigated enthusiasm for anions in the astrophysical community2. Many of these species are new and entail characterization. How they are formed in astrophysical sources is a question of major relevance. The anion presence in ISM was first predicted theoretically on the basis of electron affinities and on the negative linear chain molecular stabilities. Although very early, they were considered in astrochemical models3-4, their discovery is so recent because their abundances seem to be relatively low. These have to be understood in terms of molecular stabilities, reaction probabilities and radiative and collisional excitations. Then, we present our theoretical work on even carbon chains type Cn and CnH (n=2,4,6) focused to the understanding of anion abundances. We use highly correlated ab initio methods. We performed spectroscopic studies of various isomers that can play important roles as intermediates5-8. In previous papers9-10, we compared C2H and C2H- collisional rates responsible for observed line intensities. Actually, we study hydrogen attachment (Cn +H ? CnH and Cn- +H ? CnH-) and associative detachment processes (Cn- +H ? CnH +e-) for 2, 4 and 6 carbon atom chains11. [1] M.C.McCarthy, C.A.Gottlieb, H.Gupta, P.Thaddeus, Astrophys.J, 652, L141 (2006) [2] V.M.Bierbaum, J.Cernicharo, R.Bachiller, eds., 2011, pp 383-389. [3] A. Dalgarno, R.A. Mc Cray, Astrophys.J,, 181, 95 (1973) [4] E. Herbst E., Nature, 289, 656 (1981); [5] H.Massó, M.L.Senent, P.Rosmus, M.Hochlaf, J.Chem.Phys., 124, 234304 (2006) [6] M.L.Senent, M.Hochlaf, Astrophys. J. , 708, 1452(2010) [7] H.Massó, M.L.Senent, J.Phys.Chem.A, 113, 12404 (2009) [8] D. Hammoutene, M.Hochlaf, M.L.Senent, submitted. [9] A. Spielfiedel, N. Feautrier, F. Najar, D. ben Abdallah, F. Dayou, M.L. Senent, F. Lique, Mon.Not.R.Astron.Soc., 421, 1891 (2012) [10] F.Dumouchel, A, Spielfieldel , M.L.Senent, N.Feautrier, Chem. Phys. Lett., 533, 6 (2012) [11] M.L.Senent, M.Hochlaf, submitted

Senent, Maria Luisa

2012-05-01

64

Anion exchange behavior of nobelium  

Microsoft Academic Search

The anion exchange behavior of 255No produced by the 248Cm(12C,5n) reaction has been investigated in 11.5M HCl, 4M HCl and 8M HNO3 to deduce the behavior of 'primordial 257No' produced via 248Cm(18O,5n)261Rf 257No before anion exchange separation in the 261Rf experiment. It was found that 255No is mostly eluted from the anion exchange column with these solutions. The contribution of

A. Toyoshima; K. Tsukada; H. Haba; M. Asai; S. Goto; K. Akiyama; I. Nishinaka; S. Ichikawa; Y. Nagame; A. Shinohara

2003-01-01

65

Anion permselective membrane  

NASA Technical Reports Server (NTRS)

The synthesis and fabrication of polymeric anion permselective membranes for redox systems are discussed. Variations of the prime candidate anion membrane formulation to achieve better resistance and/or lower permeability were explored. Processing parameters were evaluated to lower cost and fabricate larger sizes. The processing techniques to produce more membranes per batch were successfully integrated with the fabrication of larger membranes. Membranes of about 107 cm x 51 cm were made in excellent yield. Several measurements were made on the larger sample membranes. Among the data developed were water transport and transference numbers for these prime candidate membranes at 20 C. Other work done on this system included characterization of a number of specimens of candidate membranes which had been returned after service lives of up to sixteen months. Work with new polymer constituents, with new N.P.'s, catalysts and backing fabrics is discussed. Some work was also done to evaluate other proportions of the ingredients of the prime candidate system. The adoption of a flow selectivity test at elevated temperature was explored.

Hodgdon, R. B.; Waite, W. A.

1982-01-01

66

Relative Acidifying Activity of Anionic Salts Commonly Used to Prevent Milk Fever  

Microsoft Academic Search

High cation diets can cause milk fever in dairy cows as they induce a metabolic alkalosis reducing the abil- ity of the cow to maintain calcium homeostasis at the onset of lactation. Adding anions to the diet can offset the effect of the high cation forages by inducing a mild metabolic acidosis, restoring the ability to maintain calcium homeostasis. The

J. P. Goff; R. Ruiz; R. L. Horst

2004-01-01

67

Diffuse large B-cell lymphoma: A metabolic disorder?  

PubMed Central

Patient Male, 81 Final Diagnosis: Non-Hodgkin lymphoma Symptoms: General weakness • hypoglycemia • metabolic acidosis Medication: — Clinical Procedure: — Specialty: Hematology Objective: Challenging differential diagnosis Background: B cell lymphoma constitutes 80–85% of cases of Non Hodgkin’s lymphoma in the Untied States. Metabolic complications may arise from the disease itself or through its end organ involvement. Case Report: We describe a case of a diffuse large B cell lymphoma diagnosed by abdominal computed tomography after it initially presented as hypoglycemia not correctable by dextrose infusion that instead resulted in increased anion gap metabolic acidosis with elevated lactate levels. Conclusions: The case illustrates how lymphomas can present unusually with hypoglycemia and lactic acidosis, the latter being an ominous sign that can occur without liver involvement. In this regard, the case demonstrates the metabolic sequelae of lymphoma that should raise suspicion for an underlying process. This has implications for diagnosis, treatment, and patient survival. Attention should be paid especially in the primary care setting in order to minimize delays in diagnosis. PMID:24349605

Tanios, Georges; Aranguren, Ines M.; Goldstein, Jack S.; Patel, Chirag B.

2013-01-01

68

Organic Anion Transporting Polypeptides  

PubMed Central

Organic anion transporting polypeptides or OATPs are central transporters in the disposition of drugs and other xenobiotics. In addition, they mediate transport of a wide variety of endogenous substrates. The critical role of OATPs in drug disposition has spurred research both in academia and in the pharmaceutical industry. Translational aspects with clinical questions are the focus in academia, while the pharmaceutical industry tries to define and understand the role these transporters play in pharmacotherapy. The present overview summarizes our knowledge on the interaction of food constituents with OATPs, and on the OATP transport mechanisms. Further, it gives an update on the available information on the structure-function relationship of the OATPs, and finally, covers the transcriptional and posttranscriptional regulation of OATPs. PMID:24745984

Stieger, Bruno; Hagenbuch, Bruno

2013-01-01

69

Anion Transport with Halogen Bonds.  

PubMed

This review covers the application of halogen bonds to transport anions across lipid bilayer membranes. The introduction provides a brief description of biological and synthetic transport systems. Emphasis is on examples that explore interactions beyond the coordination with lone pairs or hydrogen bonds for the recognition of cations and anions, particularly cation-? and anion-? interactions, and on structural motifs that are relevant for transport studies with halogen bonds. Section 2 summarizes the use of macrocyclic scaffolds to achieve transport with halogen bonds, focusing on cyclic arrays of halogen-bond donors of different strengths on top of calixarene scaffolds. This section also introduces methods to study anion binding in solution and anion transport in fluorogenic vesicles. In Sect. 3, transport studies with monomeric halogen bond-donors are summarized. This includes the smallest possible organic anion transporter, trifluoroiodomethane, a gas that can be bubbled through a suspension of vesicles to turn on transport. Anion transport with a gas nicely illustrates the power of halogen bonds for anion transport. Like hydrogen bonds, they are directional and strong, but compared to hydrogen-bond donors, halogen-bond donors are more lipophilic. Section 3 also offers a concise introduction to the measurement of ion selectivity in fluorogenic vesicles and conductance experiments in planar bilayer membranes. Section 4 introduces the formal unrolling of cyclic scaffolds into linear scaffolds that can span lipid bilayers. As privileged transmembrane scaffolds, the importance of hydrophobically matching fluorescent p-oligophenyl rods is fully confirmed. The first formal synthetic ion channel that operates by cooperative multiion hopping along transmembrane halogen-bonding cascades is described. Compared to homologs for anion-? interactions, transport with halogen bonds is clearly more powerful. PMID:24696354

Jentzsch, Andreas Vargas; Matile, Stefan

2014-04-01

70

Anion transporters and biological systems.  

PubMed

In this Account, we discuss the development of new lipid bilayer anion transporters based on the structure of anionophoric natural products (the prodigiosins) and purely synthetic supramolecular systems. We have studied the interaction of these compounds with human cancer cell lines, and, in general, the most active anion transporter compounds possess the greatest anti-cancer properties. Initially, we describe the anion transport properties of synthetic molecules that are based on the structure of the family of natural products known as the prodiginines. Obatoclax, for example, is a prodiginine derivative with an indole ring that is currently in clinical trials for use as an anti-cancer drug. The anion transport properties of the compounds were correlated with their toxicity toward small cell human lung cancer GLC4 cells. We studied related compounds with enamine moieties, tambjamines, that serve as active transporters. These molecules and others in this series could depolarize acidic compartments within GLC4 cells and trigger apoptosis. In a study of the variation of lipophilicity of a series of these compounds, we observed that, as log P increases, the anion transport efficiency reaches a peak and then decreases. In addition, we discuss the anion transport properties of series of synthetic supramolecular anion receptor species. We synthesized trisureas and thioureas based on the tren backbone, and found that the thiourea compounds effectively transport anions. Fluorination of the pendant phenyl groups in this series of compounds greatly enhances the transport properties. Similar to our earlier results, the most active anion transporters reduced the viability of human cancer cell lines by depolarizing acidic compartments in GLC4 cells and triggering apoptosis. In an attempt to produce simpler transporters that obey Lipinski's Rule of Five, we synthesized simpler systems containing a single urea or thiourea group. Once again the thiourea systems, and in particular a thiourea with a pendant indole group, transported anions efficiently. A series of related compounds containing a pendant trifluoromethyl group showed enhanced transport and significant anticancer properties. Researchers still need to determine of the exact mechanism of how these compounds depolarize acidic organelles within cancer cells. However, this work shows that these transporters based upon both natural products and purely synthetic supramolecular systems transport anions, depolarize acidic compartments within cancer cells and trigger apoptosis. PMID:23551251

Gale, Philip A; Pérez-Tomás, Ricardo; Quesada, Roberto

2013-12-17

71

Effect of Anionic Salts in Prepartum Diets Based on Alfalfa1  

Microsoft Academic Search

This study compared prepartum diets based on grass, alfalfa, or alfalfa and anionic salts to inves- tigate their effect on Ca metabolism, acid-base status, endocrine response, disease incidence, and lactational performance of periparturient dairy cows. Forty-five nonlactating Holstein cows in their last 3 wk of gesta- tion were fed a control diet based on grass hay with a dietary cation-anion

P. W. Joyce; W. K. Sanchez; J. P. Goff

1997-01-01

72

computational group theory with GAP 1 GAP in Sage  

E-print Network

computational group theory with GAP 1 GAP in Sage the GAP system combinatorics and list 2013 1 / 44 #12;computational group theory with GAP 1 GAP in Sage the GAP system combinatorics and list explicitly in Sage via 1 the class Gap, do help(gap); or 2 opening a Terminal Session with GAP, type gap

Verschelde, Jan

73

Anion exchange polymer electrolytes  

DOEpatents

Solid anion exchange polymer electrolytes and compositions comprising chemical compounds comprising a polymeric core, a spacer A, and a guanidine base, wherein said chemical compound is uniformly dispersed in a suitable solvent and has the structure: ##STR00001## wherein: i) A is a spacer having the structure O, S, SO.sub.2, --NH--, --N(CH.sub.2).sub.n, wherein n=1-10, --(CH.sub.2).sub.n--CH.sub.3--, wherein n=1-10, SO.sub.2-Ph, CO-Ph, ##STR00002## wherein R.sub.5, R.sub.6, R.sub.7 and R.sub.8 each are independently --H, --NH.sub.2, F, Cl, Br, CN, or a C.sub.1-C.sub.6 alkyl group, or any combination of thereof; ii) R.sub.9, R.sub.10, R.sub.11, R.sub.12, or R.sub.13 each independently are --H, --CH.sub.3, --NH.sub.2, --NO, --CH.sub.nCH.sub.3 where n=1-6, HC.dbd.O--, NH.sub.2C.dbd.O--, --CH.sub.nCOOH where n=1-6, --(CH.sub.2).sub.n--C(NH.sub.2)--COOH where n=1-6, --CH--(COOH)--CH.sub.2--COOH, --CH.sub.2--CH(O--CH.sub.2CH.sub.3).sub.2, --(C.dbd.S)--NH.sub.2, --(C.dbd.NH)--N--(CH.sub.2).sub.nCH.sub.3, where n=0-6, --NH--(C.dbd.S)--SH, --CH.sub.2--(C.dbd.O)--O--C(CH.sub.3).sub.3, --O--(CH.sub.2).sub.n--CH--(NH.sub.2)--COOH, where n=1-6, --(CH.sub.2).sub.n--CH.dbd.CH wherein n=1-6, --(CH.sub.2).sub.n--CH--CN wherein n=1-6, an aromatic group such as a phenyl, benzyl, phenoxy, methylbenzyl, nitrogen-substituted benzyl or phenyl groups, a halide, or halide-substituted methyl groups; and iii) wherein the composition is suitable for use in a membrane electrode assembly.

Kim, Yu Seung; Kim, Dae Sik; Lee, Kwan-Soo

2013-07-23

74

Organic anion uptake by hepatocytes.  

PubMed

Many of the compounds taken up by the liver are organic anions that circulate tightly bound to protein carriers such as albumin. The fenestrated sinusoidal endothelium of the liver permits these compounds to have access to hepatocytes. Studies to characterize hepatic uptake of organic anions through kinetic analyses, suggested that it was carrier-mediated. Attempts to identify specific transporters by biochemical approaches were largely unsuccessful and were replaced by studies that utilized expression cloning. These studies led to identification of the organic anion transport proteins (oatps), a family of 12 transmembrane domain glycoproteins that have broad and often overlapping substrate specificities. The oatps mediate Na(+)-independent organic anion uptake. Other studies identified a seven transmembrane domain glycoprotein, Na(+)/taurocholate transporting protein (ntcp) as mediating Na(+)-dependent uptake of bile acids as well as other organic anions. Although mutations or deficiencies of specific members of the oatp family have been associated with transport abnormalities, there have been no such reports for ntcp, and its physiologic role remains to be determined, although expression of ntcp in vitro recapitulates the characteristics of Na(+)-dependent bile acid transport that is seen in vivo. Both ntcp and oatps traffic between the cell surface and intracellular vesicular pools. These vesicles move through the cell on microtubules, using the microtubule based motors dynein and kinesins. Factors that regulate this motility are under study and may provide a unique mechanism that can alter the plasma membrane content of these transporters and consequently their accessibility to circulating ligands. PMID:25428858

Wolkoff, Allan W

2014-10-01

75

Neutral and anionic superhalogen hydroxides  

NASA Astrophysics Data System (ADS)

The properties of superhalogen M(OH)k+1- anions and their M(OH) k+1 neutral parents (where M = Li, Na, K, Be, Mg, Ca, B, Al, Ga) were investigated at the ab initio CCSD(T)/6-311++G(3df,3pd)//MP2/6-311++G(d,p) level of theory. All the M(OH)k+1- anions and some of their M(OH) k+1 neutral parents ( k is the maximal formal valence of M) were found to be thermodynamically stable against the fragmentations (OH, OH -, O 2 or H 2O loss). The vertical electron detachment energies (VDE) of the M(OH)k+1- anions were calculated with the OVGF method and using the 6-311++G(3df,3pd) basis sets. The VDE values calculated for the anions studied exceed 4 eV in all cases, whereas the largest values of the electron binding energies were found for the Al(OH)4- (6.07 eV) and Ga(OH)4- anions (6.21 eV). Finally, formation of most of the species considered was predicted to be spontaneous due to the lack of kinetic barriers for these processes and their thermodynamic favorability.

?wierszcz, Iwona; Anusiewicz, Iwona

2011-05-01

76

Predicting timothy mineral concentrations, dietary cation-anion difference, and grass tetany index by near-infrared reflectance spectroscopy  

Microsoft Academic Search

The mineral concentration of forage grasses plays a significant role in 2 metabolic disorders in dairy cattle production, namely, hypocalcemia (milk fever) and hy- pomagnesemia (grass tetany). Risks of occurrence of these 2 metabolic disorders can be evaluated by deter- mining the dietary cation-anion difference (DCAD) and the grass tetany (GT) index of forages and specific ra- tions. The objective

G. F. Tremblay; Z. Nie; G. Bélanger; S. Pelletier; G. Allard

2009-01-01

77

Anionic synthesis of telechelic polyacetylene  

Microsoft Academic Search

Poly(phenyl vinyl sulfoxide) which is a soluble precursor to polyacetylene can be prepared using the ‘living’ anionic synthesis method. The thermal labile sulfoxide moieties can be readily converted to acetylenic units upon heating. In this report, a series of monodisperse end-functionalized soluble precursors were prepared. Details on the synthesis and characterization procedures were described. The end groups were either Li,

Louis M Leung; Wei-Dong He

2001-01-01

78

Anion separation with metal-organic frameworks  

SciTech Connect

The application of metal-organic frameworks (MOFs) to anion separations with a special emphasis on anion selectivity is reviewed. The coordination frameworks are classified on the basis of the main interactions to the included anion, from weak and non-specific van der Waals forces to more specific interactions such as coordination to Lewis acid metal centers or hydrogen bonding. The importance of anion solvation phenomena to the observed anion selectivities is highlighted, and strategies for reversing the Hofmeister bias that favors large, less hydrophilic anions, and for obtaining peak selectivities based on shape recognition are delineated. Functionalization of the anion-binding sites in MOFs with strong and directional hydrogen-bonding groups that are complementary to the included anion, combined with organizational rigidity of the coordination framework, appears to be the most promising approach for achieving non-Hofmeister selectivity.

Custelcean, Radu [ORNL; Moyer, Bruce A [ORNL

2007-01-01

79

Ion exchange polymers for anion separations  

DOEpatents

Anion exchange resins including at least two positively charged sites and a ell-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

Jarvinen, Gordon D. (Los Alamos, NM); Marsh, S. Fredric (Los Alamos, NM); Bartsch, Richard A. (Lubbock, TX)

1997-01-01

80

Ion exchange polymers for anion separations  

DOEpatents

Anion exchange resins including at least two positively charged sites and a well-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

Jarvinen, G.D.; Marsh, S.F.; Bartsch, R.A.

1997-09-23

81

Nitrite anion stimulates ischemic arteriogenesis involving NO metabolism.  

PubMed

Nitric oxide (NO) is a potential regulator of ischemic vascular remodeling, and as such therapies augmenting its bioavailability may be useful for the treatment of ischemic tissue diseases. Here we examine the effect of administering the NO prodrug sodium nitrite on arteriogenesis activity during established tissue ischemia. Chronic hindlimb ischemia was induced by permanent unilateral femoral artery and vein ligation. Five days postligation; animals were randomized to control PBS or sodium nitrite (165 ?g/kg) therapy twice daily. In situ vascular remodeling was measured longitudinally using SPY angiography and Microfil vascular casting. Delayed sodium nitrite therapy rapidly increased ischemic limb arterial vessel diameter and branching in a NO-dependent manner. SPY imaging angiography over time showed that nitrite therapy enhanced ischemic gracillis collateral vessel formation from the profunda femoris to the saphenous artery. Immunofluorescent staining of smooth muscle cell actin also confirmed that sodium nitrite therapy increased arteriogenesis in a NO-dependent manner. The NO prodrug sodium nitrite significantly increases arteriogenesis and reperfusion of established severe chronic tissue ischemia. PMID:22610173

Bir, Shyamal C; Pattillo, Christopher B; Pardue, Sibile; Kolluru, Gopi K; Docherty, John; Goyette, Dave; Dvorsky, Peter; Kevil, Christopher G

2012-07-15

82

A REVIEW ON ACID BASE STATUS IN DAIRY COWS: IMPLICATIONS OF DIETARY CATION-ANION BALANCE  

Microsoft Academic Search

The acid base status of a dairy cow is maintained within a narrow range. The key mechanisms involving blood, cells and lungs, perform this function. Although other minerals have an impact on acid base metabolism, the minerals used in dietary cation-anion balance (DCAB) namely sodium (Na), potassium (K) and chloride (Cl) have the greatest effect. Hence, acid base status implicates

D. Afzaal; M. Nisa; M. A. Khan; M. Sarwar

2004-01-01

83

Competition between monovalent and divalent anions for calcined and uncalcined hydrotalcite: anion exchange and adsorption sites  

Microsoft Academic Search

Hydrotalcite compounds are well-known anion exchangers. Their anionic exchange capacity (A.E.C.) increases with thermal treatment together with their specific surface area and porosity. In the presence of mono- and divalent anions such as Cl?, SO42? and CrO42?, calcined hydrotalcite behaves not only as an anion exchanger but also as an oxide adsorbent. In the case of divalent anions, the adsorbed

L. Châtelet; J. Y. Bottero; J. Yvon; A. Bouchelaghem

1996-01-01

84

Polymerization of anionic wormlike micelles.  

PubMed

Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles. PMID:16430253

Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

2006-01-31

85

Aza compounds as anion receptors  

SciTech Connect

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Qing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

1998-01-06

86

Aza compounds as anion receptors  

DOEpatents

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

Lee, H.S.; Yang, X.Q.; McBreen, J.

1998-01-06

87

Metabolic Syndrome  

MedlinePLUS

... is a signal that someone could be on the road to serious health problems. Diagnosing metabolic syndrome helps ... like heart disease or type 2 diabetes down the road. What Exactly Is Metabolic Syndrome? Metabolic syndrome is ...

88

NATIONAL GAP ANALYSIS PROGRAM  

EPA Science Inventory

GAP Analysis is a rapid conservation evaluation method for assessing the current status of biodiversity at large spatial scales. GAP Analysis provides a systematic approach for evaluating the protection afforded biodiversity in given areas. It uses Geographic Information System (...

89

Prediction of urinary and blood pH in non-lactating dairy cows fed anionic diets  

Microsoft Academic Search

Anionic diets are fed to non-lactating pre-parturient cows to lower the dietary cation–anion difference index (DCAD), thereby limiting their risk of contracting milk fever, and other associated metabolic diseases, in early lactation. Data from 21 studies (86 dietary treatments) with dry dairy cows, published in referred scientific journals, were identified for meta-analysis to predict urinary and blood pH (pHu and

M Spanghero

2004-01-01

90

Functionalized anion exchange stationary phase for separation of anionic compounds.  

PubMed

Synthesis of the multilayered stationary phases containing quaternary ammonium functional groups on the silica support was described. Bonded phases were characterized by elemental analysis, solid state (13)C NMR spectroscopy and chromatographic methods. The surface of silica support was coated with different number of polymeric layers formed by condensation polymerization of primary amine (methylamine) with diepoxide (1,4-butanedioldiglycidyl ether). A series of stationary phases with different number of polymerized layers were tested. Separation of an inorganic anions sample (F(-), Cl(-), NO2(-), Br(-), NO3(-)) and nucleotides was performed. PMID:24913867

Bocian, Szymon; Studzi?ska, Sylwia; Buszewski, Bogus?aw

2014-09-01

91

Raman gap solitons  

PubMed

We show that an intense pump pulse, detuned far from the Bragg resonance of a nonlinear periodic structure, can excite a gap soliton at a wavelength within the band gap that corresponds to the Raman shift of the medium. This Raman gap soliton is a stable, long-lived, quasistationary excitation that exists within the grating even after the pump pulse has passed. We find both stationary solitons as well as slow Raman gap solitons with velocities as low as 1% of the speed of light. The predicted phenomena should be observable in fiber Bragg gratings and other nonlinear photonic band gap structures. PMID:11019152

Winful; Perlin

2000-04-17

92

Diffusive anion exchange in polypyrrole films  

SciTech Connect

Anion-exchange experiments performed on electrochemically prepared thin films of polypyrrole/ClO/sub 4//sup -/ demonstrate that the anions are not tightly bound to the polymer matrix. Auger electron spectroscopy reveals that ClO/sub 4//sup -/ can be replaced by a number of different anions. In addition, certain anions will not replace ClO/sub 4//sup -/ while others will induce only partial replacement. The relevance of entropic and steric factors is discussed in relationship to the exchange process.

Curtin, L.S.; Komplin, G.C.; Pietro, W.J.

1988-01-14

93

Metal-cation-based anion exchange membranes.  

PubMed

Here we present the first metal-cation-based anion exchange membranes (AEMs), which were synthesized by copolymerization and cross-linking of a norbornene monomer functionalized with a water-soluble bis(terpyridine)ruthenium(II) complex and dicyclopentadiene. Each ruthenium complex has two associated counteranions, unlike most ammonium- and phosphonium-based membranes with single cation-anion pairs. The resulting AEMs show anion conductivities and mechanical properties comparable to those of traditional quaternary-ammonium-based AEMs as well as good alkaline stability and methanol tolerance. These results suggest that metal-cation-based polymers hold promise as a new class of materials for anion-conducting applications. PMID:22385221

Zha, Yongping; Disabb-Miller, Melanie L; Johnson, Zachary D; Hickner, Michael A; Tew, Gregory N

2012-03-14

94

Anion polarizability functions in alkali halide crystals  

NASA Astrophysics Data System (ADS)

Anion polarizabilities in alkali halide crystals are analysed as a function of interionic separation R . The anion polarizability is treated as a function of the anion and cation radii, with its partial derivatives approximated by those with respect to R for fixed cation and anion, respectively. With pressure derivatives of the ionic radii deduced from the crystal compressibility, assuming transferability among crystals, the polarizability derivatives with respect to ionic radius yield pressure derivatives of the polarizability that agree with experiment to within a factor of two. These results offer a useful means of predicting the pressure dependence of dielectric data.

Batana, A.; Bruno, J.; Munn, R. W.

95

The gap gene network  

PubMed Central

Gap genes are involved in segment determination during the early development of the fruit fly Drosophila melanogaster as well as in other insects. This review attempts to synthesize the current knowledge of the gap gene network through a comprehensive survey of the experimental literature. I focus on genetic and molecular evidence, which provides us with an almost-complete picture of the regulatory interactions responsible for trunk gap gene expression. I discuss the regulatory mechanisms involved, and highlight the remaining ambiguities and gaps in the evidence. This is followed by a brief discussion of molecular regulatory mechanisms for transcriptional regulation, as well as precision and size-regulation provided by the system. Finally, I discuss evidence on the evolution of gap gene expression from species other than Drosophila. My survey concludes that studies of the gap gene system continue to reveal interesting and important new insights into the role of gene regulatory networks in development and evolution. PMID:20927566

2010-01-01

96

GapZappers  

NSDL National Science Digital Library

In this online Flash activity students use their knowledge of addition of fractions and equivalent forms to navigate 15 levels of play. Each level progresses in difficulty and includes gaps measured in meters that students must fill in using fractional pieces to enable the lizard to move on in the field of play. Once the gap is filled, check the gap and the lizard will move on showing the fractional equation that solved the problem.

King, Colleen

2013-01-01

97

Photodissociation of nitromethane cluster anions  

SciTech Connect

Three types of anionic fragments are observed in the photodissociation of nitromethane cluster anions, (CH{sub 3}NO{sub 2}){sub n}{sup -}, n=1-6, at 355 nm: NO{sub 2}{sup -}(CH{sub 3}NO{sub 2}){sub k}, (CH{sub 3}NO{sub 2}){sub k}{sup -}, and OH{sup -} (kanion core, CH{sub 3}NO{sub 2}{sup -}, solvated by n-1 neutral nitromethane molecules. The NO{sub 2}{sup -}(CH{sub 3}NO{sub 2}){sub k} and OH{sup -} fragments formed from these clusters are described as core-dissociation products, while the (CH{sub 3}NO{sub 2}){sub k}{sup -} fragments are attributed to energy transfer from excited CH{sub 3}NO{sub 2}{sup -} into the solvent network or a core-dissociation--recombination (caging) mechanism. As with other cluster families, the fraction of caged photofragments shows an overall increase with increasing cluster size. The low-lying A{sup 2}A{sup '} and/or B{sup 2}A{sup '} electronic states of CH{sub 3}NO{sub 2}{sup -} are believed responsible for photoabsorption leading to dissociation to NO{sub 2}{sup -} based fragments, while the C{sup 2}A{sup ''} state is a candidate for the OH{sup -} pathway. Compared to neutral nitromethane, the photodissociation of CH{sub 3}NO{sub 2}{sup -} requires lower energy photons because the photochemically active electron occupies a high energy {pi}{sup *} orbital (which is vacant in the neutral). Although the electronic states in the photodissociation of CH{sub 3}NO{sub 2} and CH{sub 3}NO{sub 2}{sup -} are different, the major fragments, CH{sub 3}+NO{sub 2} and CH{sub 3}+NO{sub 2}{sup -}, respectively, both form via C-N bond cleavage.

Goebbert, Daniel J.; Khuseynov, Dmitry; Sanov, Andrei [Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 84721-0041 (United States)

2010-08-28

98

Covalent Polymers Containing Discrete Heterocyclic Anion Receptors  

PubMed Central

This chapter covers recent advances in the development of polymeric materials containing discrete heterocyclic anion receptors, and focuses on advances in anion binding and chemosensor chemistry. The development of polymers specific for anionic species is a relatively new and flourishing area of materials chemistry. The incorporation of heterocyclic receptors capable of complexing anions through non-covalent interactions (e.g., hydrogen bonding and electrostatic interactions) provides a route to not only sensitive but also selective polymer materials. Furthermore, these systems have been utilized in the development of polymers capable of extracting anionic species from aqueous environments. These latter materials may lead to advances in water purification and treatment of diseases resulting from surplus ions. PMID:20871791

Rambo, Brett M.; Silver, Eric S.; Bielawski, Christopher W.; Sessler, Jonathan L.

2010-01-01

99

Anion channels: master switches of stress responses.  

PubMed

During stress, plant cells activate anion channels and trigger the release of anions across the plasma membrane. Recently, two new gene families have been identified that encode major groups of anion channels. The SLAC/SLAH channels are characterized by slow voltage-dependent activation (S-type), whereas ALMT genes encode rapid-activating channels (R-type). Both S- and R-type channels are stimulated in guard cells by the stress hormone ABA, which leads to stomatal closure. Besides their role in ABA-dependent stomatal movement, anion channels are also activated by biotic stress factors such as microbe-associated molecular patterns (MAMPs). Given that anion channels occur throughout the plant kingdom, they are likely to serve a general function as master switches of stress responses. PMID:22381565

Roelfsema, M Rob G; Hedrich, Rainer; Geiger, Dietmar

2012-04-01

100

Cumulenic and heterocumulenic anions: potential interstellar species?  

NASA Astrophysics Data System (ADS)

A recent theoretical investigation by Terzieva & Herbst of linear carbon chains, Cn where n>=6, in the interstellar medium has shown that these species can undergo efficient radiative association to form the corresponding anions. An experimental study by Barckholtz, Snow & Bierbaum of these anions has demonstrated that they do not react efficiently with molecular hydrogen, leading to the possibility of detectable abundances of cumulene-type anions in dense interstellar and circumstellar environments. Here we present a series of electronic structure calculations which examine possible anionic candidates for detection in these media, namely the anion analogues of the previously identified interstellar cumulenes CnH and Cn-1CH2 and heterocumulenes CnO (where n=2-10). The extraordinary electron affinities calculated for these molecules suggest that efficient radiative electron attachment could occur, and the large dipole moments of these simple (generally) linear molecules point to the possibility of detection by radio astronomy.

Blanksby, Stephen J.; McAnoy, Andrew M.; Dua, Suresh; Bowie, John H.

2001-11-01

101

2-(3,5-Dinitrophenyl)-1,3-dithiane carbanion: a benzylic anion with a low energy triplet state.  

PubMed

Calculations at the DFT level predict that benzyl anions with strong ?-electron-withdrawing groups in the meta position(s) have low energy diradical or triplet electronic states. Specifically, the 2-(3,5-dinitrophenyl)-1,3-dithiane carbanion is predicted to have nearly degenerate singlet and triplet states at the (U)B3LYP level as a free anion. Its lithium ion pair is predicted to be a ground-state triplet with a substantial (26 kcal/mol) singlet-triplet energy gap. Experiments on this anion using chemical trapping, NMR, and the Evans method strongly suggest that this anion is either a triplet or a ground-state singlet with a very low energy triplet state. PMID:21870822

Perrotta, Raffaele R; Winter, Arthur H; Coldren, William H; Falvey, Daniel E

2011-10-01

102

Anion stripping as a general method to create cationic porous framework with mobile anions.  

PubMed

Metal-organic frameworks (MOFs) with cationic frameworks and mobile anions have many applications from sensing, anion exchange and separation, to fast ion conductivity. Despite recent progress, the vast majority of MOFs have neutral frameworks. A common mechanism for the formation of neutral frameworks is the attachment of anionic species such as F(-) or OH(-) to the framework metal sites, neutralizing an otherwise cationic scaffolding. Here, we report a general method capable of converting such neutral frameworks directly into cationic ones with concurrent generation of mobile anions. Our method is based on the differential affinity between distinct metal ions with framework anionic species. Specifically, Al(3+) is used to strip F(-) anions away from framework Cr(3+) sites, leading to cationic frameworks with mobile Cl(-) anions. The subsequent anion exchange with OH(-) further leads to a porous network with mobile OH(-) anions. New materials prepared by anion stripping can undergo ion exchange with anionic organic dyes and also exhibit much improved ionic conductivity compared to the original unmodified MOFs. PMID:24836691

Mao, Chengyu; Kudla, Ryan A; Zuo, Fan; Zhao, Xiang; Mueller, Leonard J; Bu, Xianhui; Feng, Pingyun

2014-05-28

103

Metabolic Syndrome  

MedlinePLUS

... to occur together. You must have at least three metabolic risk factors to be diagnosed with metabolic syndrome. A large ... syndrome may overtake smoking as the leading risk factor for heart disease. It is possible to prevent or ... Metabolic Syndrome Clinical Trials Clinical trials are ...

104

Gap year volunteer tourism  

Microsoft Academic Search

The valorisation of cross-cultural understanding and promotion of an ethic of global citizenship are at the forefront of the recent development and proliferation of international ‘gap year’ travel programs and policies. Governments and industry alike promote gap year travel uncritically as a guaranteed pathway to the development of inclusive ideologies associated with global citizenship. In this paper we examine how

Stephen Wearing; John Neil

105

Bridging a Cultural Gap  

ERIC Educational Resources Information Center

There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

Leviatan, Talma

2008-01-01

106

Hole localization, migration, and the formation of peroxide anion in perovskite SrTiO3  

NASA Astrophysics Data System (ADS)

Hybrid density functional calculations are carried out to investigate the behavior of holes in SrTiO3. As in many other oxides, it is shown that a hole tend to localize on one oxygen forming an O- anion with a concomitant lattice distortion; therefore a hole polaron. The calculated emission energy from the recombination of the localized hole and a conduction-band electron is about 2.5 eV, in good agreement with experiments. Therefore the localization of the hole or self-trapping is likely to be responsible for the green photoluminescence at low temperature, which was previously attributed to an unknown defect state. Compared to an electron, the calculated hole polaron mobility is three orders of magnitude lower at room temperature. In addition, two O- anions can bind strongly to form an O22- peroxide anion. No electronic states associated with the O22- peroxide anion are located inside the band gap or close to the band edges, indicating that it is electronically inactive. We suggest that in addition to the oxygen vacancy, the formation of the O22- peroxide anion can be an alternative to compensate acceptor doping in SrTiO3.

Chen, Hungru; Umezawa, Naoto

2014-07-01

107

Anaerobic Metabolism 1 ANAEROBIC METABOLISM  

E-print Network

to aerobic metabolsm. This said, it is not uncommon to hear microbiologists talk about anaerobic respiration it for respiration. However, in many animals anaerobic metabolism may occur even when there are large amounts of O2Anaerobic Metabolism 1 ANAEROBIC METABOLISM 1 Introduction About the Next Three Sets of Class Notes

Prestwich, Ken

108

Timothy Hay with a Low Dietary Cation-Anion Difference Improves Calcium Homeostasis in Periparturient Holstein Cows  

Microsoft Academic Search

The current study was undertaken to evaluate the effects of feeding timothy (Phleum pratense L.) hay dif- fering in dietary cation-anion difference (DCAD) on the capability of cows to maintain calcium homeostasis around parturition. We hypothesized that feeding low- DCAD timothy hay during the prepartum period would induce a mild metabolic acidosis prepartum and im- prove calcium homeostasis postpartum with

G. B. Penner; G. F. Tremblay; T. Dow; M. Oba

2008-01-01

109

Can gap junctions deliver?  

PubMed

In vivo delivery of small interfering RNAs (siRNAs) to target cells via the extracellular space has been hampered by dilution effects and immune responses. Gap junction-mediated transfer between cells avoids the extracellular space and its associated limitations. Because of these advantages cell based delivery via gap junctions has emerged as a viable alternative for siRNA or miRNA delivery. Here we discuss the advantages and disadvantages of extracellular delivery and cell to cell delivery via gap junction channels composed of connexins. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics. PMID:21986484

Brink, Peter R; Valiunas, Virginijus; Gordon, Chris; Rosen, Michael R; Cohen, Ira S

2012-08-01

110

The Voltage-dependent Anion Channel in Endoplasmic\\/Sarcoplasmic Reticulum: Characterization, Modulation and Possible Function  

Microsoft Academic Search

In recent years, it has been recognized that there is a metabolic coupling between the cytosol, ER\\/SR and mitochondria. In this cross-talk, mitochondrial Ca2+ homeostasis and ATP production and supply play a major role. The primary transporter of adenine nucleotides, Ca2+and other metabolites into and out of mitochondria is the voltage-dependent anion channel (VDAC) located at the outer mitochondrial membrane,

V. Shoshan-Barmatz; A. Israelson

2005-01-01

111

Nucleotide interactions of the human voltage-dependent anion channel.  

PubMed

The voltage-dependent anion channel (VDAC) mediates and gates the flux of metabolites and ions across the outer mitochondrial membrane and is a key player in cellular metabolism and apoptosis. Here we characterized the binding of nucleotides to human VDAC1 (hVDAC1) on a single-residue level using NMR spectroscopy and site-directed mutagenesis. We find that hVDAC1 possesses one major binding region for ATP, UTP, and GTP that partially overlaps with a previously determined NADH binding site. This nucleotide binding region is formed by the N-terminal ?-helix, the linker connecting the helix to the first ?-strand and adjacent barrel residues. hVDAC1 preferentially binds the charged forms of ATP, providing support for a mechanism of metabolite transport in which direct binding to the charged form exerts selectivity while at the same time permeation of the Mg(2+)-complexed ATP form is possible. PMID:24668813

Villinger, Saskia; Giller, Karin; Bayrhuber, Monika; Lange, Adam; Griesinger, Christian; Becker, Stefan; Zweckstetter, Markus

2014-05-01

112

Generation gaps in engineering?  

E-print Network

There is much enthusiastic debate on the topic of generation gaps in the workplace today; what the generational differences are, how to address the apparent challenges, and if the generations themselves are even real. ...

Kim, David J. (David Jinwoo)

2008-01-01

113

California: Emigrant Gap  

Atmospheric Science Data Center

article title:  Emigrant Gap Fire, California     View Larger Image ... smoke plumes from wildfires burning throughout Northern California on August 13, 2001. The overview image represents an area of 336 ...

2014-05-15

114

Fiber optic gap gauge  

DOEpatents

A lightweight, small size, high sensitivity gauge for indirectly measuring displacement or absolute gap width by measuring axial strain in an orthogonal direction to the displacement/gap width. The gap gauge includes a preferably titanium base having a central tension bar with springs connecting opposite ends of the tension bar to a pair of end connector bars, and an elongated bow spring connected to the end connector bars with a middle section bowed away from the base to define a gap. The bow spring is capable of producing an axial strain in the base proportional to a displacement of the middle section in a direction orthogonal to the base. And a strain sensor, such as a Fabry-Perot interferometer strain sensor, is connected to measure the axial strain in the base, so that the displacement of the middle section may be indirectly determined from the measurement of the axial strain in the base.

Wood, Billy E. (Livermore, CA); Groves, Scott E. (Brentwood, CA); Larsen, Greg J. (Brentwood, CA); Sanchez, Roberto J. (Pleasanton, CA)

2006-11-14

115

SOUTHWEST REGIONAL GAP LAND COVER  

EPA Science Inventory

The Gap Analysis Program is a national inter-agency program that maps the distribution of plant communities and selected animal species and compares these distributions with land stewardship to identify gaps in biodiversity protection. GAP uses remote satellite imag...

116

[Acid-base homeostasis: metabolic acidosis and metabolic alkalosis].  

PubMed

Acid-base homeostasis ensured by the kidneys, which maintain the equilibrium between proton generation by cellular metabolism and proton excretion in urine. This requirement is lifesaving because of the protons' ability to bind to anionic proteins in the extracellular space, modifying their structure and functions. The kidneys also regenerate bicarbonates. The kidney is not the sole organ in charge of maintaining blood pH in a very narrow range; lungs are also involved since they allow a large amount of volatile acid generated by cellular respiration to be eliminated. PMID:24993393

Dussol, Bertrand

2014-07-01

117

Metabolic myopathies  

NASA Technical Reports Server (NTRS)

Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. Cardiac and systemic metabolic dysfunction may coexist. Symptoms are often intermittent and provoked by exercise or changes in supply of lipid and carbohydrate fuels. Specific disorders of lipid and carbohydrate metabolism in muscle are reviewed. Evaluation often requires provocative exercise testing. These tests may include ischemic forearm exercise, aerobic cycle exercise, and 31P magnetic resonance spectroscopy with exercise.

Martin, A.; Haller, R. G.; Barohn, R.; Blomqvist, C. G. (Principal Investigator)

1994-01-01

118

Metabolic ecology.  

PubMed

Ecological theory that is grounded in metabolic currencies and constraints offers the potential to link ecological outcomes to biophysical processes across multiple scales of organization. The metabolic theory of ecology (MTE) has emphasized the potential for metabolism to serve as a unified theory of ecology, while focusing primarily on the size and temperature dependence of whole-organism metabolic rates. Generalizing metabolic ecology requires extending beyond prediction and application of standardized metabolic rates to theory focused on how energy moves through ecological systems. A bibliometric and network analysis of recent metabolic ecology literature reveals a research network characterized by major clusters focused on MTE, foraging theory, bioenergetics, trophic status, and generalized patterns and predictions. This generalized research network, which we refer to as metabolic ecology, can be considered to include the scaling, temperature and stoichiometric models forming the core of MTE, as well as bioenergetic equations, foraging theory, life-history allocation models, consumer-resource equations, food web theory and energy-based macroecology models that are frequently employed in ecological literature. We conclude with six points we believe to be important to the advancement and integration of metabolic ecology, including nomination of a second fundamental equation, complementary to the first fundamental equation offered by the MTE. PMID:24028511

Humphries, Murray M; McCann, Kevin S

2014-01-01

119

There Are GAPS and There Are GAPS  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Guanine nucleotide-binding proteins (G proteins) transduce a very large number of cellular regulatory signals. Several recent papers have shown that the larger heterotrimeric G proteins are regulated by a class of molecules known as the RGS proteins (regulators of G protein-signaling family) that are analogous to the GAPs (GTPase activating proteins), which regulate small monomeric G proteins. Iyengar summarizes this evidence and discusses the mechanism of action of the RGS proteins.

Ravi Iyengar (Mount Sinai School of Medicine; Department of Pharmacology)

1997-01-03

120

Metabolic Syndrome  

MedlinePLUS

Having three or more risk factors is a sign that the body is resistant to insulin, an important hormone produced by the pancreas. ... diagnosed with the metabolic syndrome if you have three or more risk factors (see table below). FAcT SHeeT the metabolic syndrome ...

121

Sevelamer hydrochloride exacerbates metabolic acidosis in hemodialysis patients, depending on the dosage.  

PubMed

Sevelamer hydrochloride, as a phosphate binder that contains neither aluminum nor calcium, is expected to improve the prognosis of dialysis patients. However, sevelamer hydrochloride has been reported to lower the serum bicarbonate level. In the present study, we performed a retrospective study on the potential influences of sevelamer hydrochloride on metabolic acidosis in hemodialysis patients. The subjects were 72 patients who underwent hemodialysis at our hospital. Thirty-six patients taking sevelamer hydrochloride and 36 patients matched for sex, diabetes mellitus, age and duration of dialysis who were not taking sevelamer hydrochloride were studied. We assigned the 36 patients who had been taking sevelamer hydrochloride to the 'sevelamer group', and the 36 patients not taking sevelamer hydrochloride were the control group. Statistical significance was evaluated by a t-test and Pearson's correlation coefficient. In the sevelamer group, the mean levels of bicarbonate, base excess and pH decreased significantly after administration, compared with the values before administration, but in the control group, aggravation of acidosis was not seen. The levels of bicarbonate, base excess and pH after the medication of sevelamer hydrochloride were found to be significantly and negatively correlated with the daily dose of sevelamer hydrochloride. The levels were also found to be significantly and negatively correlated with the cumulative dose of sevelamer hydrochloride; however, the value of the mean levels of chlorine and the anion gap did not increase with sevelamer hydrochloride. Sevelamer hydrochloride caused metabolic acidosis in a dose-dependent manner in hemodialysis patients without hyperchloremia. PMID:17381531

Oka, Yoshinari; Miyazaki, Masashi; Takatsu, Shigeko; Kunitomo, Kei-ichi; Uno, Futoshi; Maruyama, Masanobu; Matsuda, Hiroaki

2007-04-01

122

Studies of anions sorption on natural zeolites.  

PubMed

This work presents results of FT-IR spectroscopic studies of anions-chromate, phosphate and arsenate - sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA(+)) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions. It was proven that aforementioned anions' sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si-O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO4(2-), AsO4(3-) and PO4(3-) ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method. PMID:25002191

Barczyk, K; Mozgawa, W; Król, M

2014-12-10

123

Uncertainties in Gapped Graphene  

E-print Network

Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.

Eylee Jung; Kwang S. Kim; DaeKil Park

2011-07-27

124

Further studies on the clinical features and clinicopathological findings of a syndrome of metabolic acidosis with minimal dehydration in neonatal calves.  

PubMed Central

A syndrome of metabolic acidosis of unknown etiology was diagnosed in twelve beef calves 7 to 31 days old. Principal clinical signs were unconsciousness or depression concomitant with weakness and ataxia. Other signs included weak or absent suckle and menace reflexes, succussable nontympanic fluid sounds in the anterior abdomen, and a slow, deep thoracic and abdominal pattern of respiration. The variation in clinical signs between calves was highly correlated (r = 0.87, P less than 0.001) with their acid-base (base deficit) status. Abnormal laboratory findings included reduced venous blood pH, pCO2 and bicarbonate ion concentration as well as hyperchloremia, elevated blood urea nitrogen, increased anion gap and neutrophilic leukocytosis with a left shift. Sodium bicarbonate solution administered intravenously effectively raised blood pH and improved demeanor, ambulation and appetite. All calves did well following a return to a normal acid-base status. PMID:3024795

Kasari, T R; Naylor, J M

1986-01-01

125

Effect of dietary potassium and anionic salts on acid-base and mineral status in periparturient cows.  

PubMed

Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage-based pre-calving diet with varying native K content affects the mineral and acid-base status in transition cows. Twenty-four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay-based diet low in K (18 g K/kg DM), and 12, a hay-based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre-partum to day 5 post-partum. Urine samples were taken on days 7 and 2 pre-partum and on day 2 post-partum. The anionic salt did not alter feed intake during the pre-partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre-partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre-partum urinary base-acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid-base excretion. Although serum Ca during the post-partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation-anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake. PMID:23796109

Rérat, M; Schlegel, P

2014-06-01

126

ANNUAL REPORT. SUPRAMOLECULAR CHEMISTRY OF SELECTIVE ANION RECOGNITION FOR ANIONS OF ENVIRONMENTAL RELEVANCE  

EPA Science Inventory

This project involves the design and synthesis of receptors for anions of environmental importance, including emphasis on high level and low activity waste. Polyammonium macrocycles as receptors and nitrate as target anion were the focus of the first phase of this project. A seco...

127

Removal of anionic reactive dyes from water using anion exchange membranes as adsorbers  

Microsoft Academic Search

Two commercial anion exchange membranes, strong basic (SB6407) and weak basic (DE81), were evaluated for the removal of anionic reactive dyes, Cibacron blue 3GA (three sulfonic acid groups per dye molecule) and Cibacron red 3BA (four sulfonic acid groups per dye molecule), from water in this study. The adsorption isotherm results show that the Langmuir maximum adsorption capacities of Cibacron

Chia-Hung Liu; Jeng-Shiou Wu; Hsin-Chieh Chiu; Shing-Yi Suen; Khim Hoong Chu

2007-01-01

128

Closing the Health Gap  

NSDL National Science Digital Library

The US Department of Health and Human Services (HHS) and ABC Radio Networks are working together to help African-Americans gain access to the best possible information regarding health issues. HHS reports that life expectancies for African-Americans lag five years behind expectancies for White Americans. The new Website Closing the Health Gap has links to information on health conditions such as diabetes and cancer as well as consumer health resources that relate to African-Americans' particular needs. Each page offers links, publications, and any news related to the subject, all in an effort to close "the health gap."

2001-01-01

129

Experimental study of the hydrothermal reactivity of organic acids and acid anions: II. Acetic acid, acetate, and valeric acid  

NASA Astrophysics Data System (ADS)

Organic acids and acid anions occur in substantial concentrations in many aqueous geologic fluids and are thought to take part in a variety of geochemical processes ranging from the transport of metals in ore-forming fluids to the formation of natural gas to serving as a metabolic energy source for microbes in subsurface habitats. The widespread occurrence of organic acids and their potential role in diverse geologic processes has led to numerous experimental studies of their thermal stability, yet there remain substantial gaps in our knowledge of the factors that control the rates and reaction pathways for the decomposition of these compounds under geologic conditions. In order to address some of these uncertainties, a series of laboratory experiments were conducted to examine the behavior of organic acids and acid anions under hydrothermal conditions in the presence of minerals. Reported here are results of experiments where aqueous solutions of acetic acid, sodium acetate, or valeric acid ( n-pentanoic acid) were heated at 325°C, 350 bars in the presence of the mineral assemblages hematite + magnetite + pyrite, pyrite + pyrrhotite + magnetite, and hematite + magnetite. The results indicate that aqueous acetic acid and acetate decompose by a combination of two reaction pathways: decarboxylation and oxidation. Both reactions are promoted by minerals, with hematite catalyzing the oxidation reaction while magnetite catalyzes decarboxylation. The oxidation reaction is much faster, so that oxidation dominates the decomposition of acetic acid and acetate when hematite is present. In contrast to previous reports that acetate decomposed more slowly than acetic acid, we found that acetate decomposed at slightly faster rates than the acid in the presence of minerals. Although longer-chain monocarboxylic acids are generally thought to decompose by decarboxylation, valeric acid appeared to decompose primarily by "deformylation" to 1-butene plus formic acid. Subsequent decomposition of 1-butene and formic acid generated a variety of short-chain (?C 4) hydrocarbons and moncarboxylic acids as well as CO 2. Valeric acid decomposition proceeded more rapidly (by a factor of 2) in the presence of hematite-magnetite-pyrite than with the other mineral assemblages, with the greater reaction rate apparently attributable to the effects of fluid chemistry. Valeric acid was observed to decompose at a substantially faster rate than acetic acid under similar conditions. The results suggest that decomposition of aqueous monocarboxylic acids may make a significant contribution to the conversion of petroleum to light hydrocarbons in natural gas and thermal fluids.

McCollom, Thomas M.; Seewald, Jeffrey S.

2003-10-01

130

Anion-? interactions of hexaaryl[3]radialenes.  

PubMed

Coordination polymers and discrete metallo-supramolecular assemblies of hexaaryl[3]radialene compounds exhibit intriguing structures with short anion to ?-centroid distances in the solid-state. Furthermore, these [3]radialene compounds display useful photophysical and electrochemical properties that make them ideal as potential platforms for anion receptors. In this study, hexafluoro[3]radialene was optimized to the MP2/aug-cc-pVTZ level of theory, and its complexes with halide anions were optimized to HF/6-31G++(d,p), MP2/6-31G++(d,p), M06-2X/6-31G++(d,p), and M06-2X/6-311G++(d,p) levels of theory. Hexafluoro[3]radialene was shown to have properties (large positive Qzz and areas of positive electrostatic surface potential) comparable to other compounds that show anion-? interactions. The interaction energies of complexes of hexafluoro[3]radialene with halide anions were calculated and found to be favorable and equivalent to those of fluorinated aromatic compounds. A series of synthetically accessible hexaaryl[3]radialenes were optimized to HF/6-31G++(d,p) theory and their complexes with halides optimized to the M06-2X/6-31G++(d,p) level of theory. The calculated properties of the electron-deficient hexaaryl[3]radialenes also show large positive Qzz quadrupole moments and two areas of positive potential; at the [3]radialene core and the acidic aryl hydrogen atoms. The interaction energies of the complexes of hexaaryl[3]radialenes and halide anions were found to follow the trend F(-) > Cl(-) ? Br(-) and correlate with the electron-deficient nature of the [3]radialene. Close contacts were observed between the anion and the radialene core and the aryl hydrogen atoms, suggesting a combination of anion-? and hydrogen bonding is important. Mass spectrometry was used to experimentally observe the complexes of a number of hexaaryl[3]radialenes with F(-), Cl(-), and Br(-) predicted computationally. Anion-[3]radialene complexes were successfully detected, and the stability of the complexes in tandem MS/MS experiments was found to support the computational results. PMID:22747096

Evans, Jack D; Hollis, Courtney A; Hack, Sandra; Gentleman, Alexander S; Hoffmann, Peter; Buntine, Mark A; Sumby, Christopher J

2012-08-01

131

Plasmodium falciparum Regulatory Subunit of cAMP-Dependent PKA and Anion Channel Conductance  

PubMed Central

Malaria symptoms occur during Plasmodium falciparum development into red blood cells. During this process, the parasites make substantial modifications to the host cell in order to facilitate nutrient uptake and aid in parasite metabolism. One significant alteration that is required for parasite development is the establishment of an anion channel, as part of the establishment of New Permeation Pathways (NPPs) in the red blood cell plasma membrane, and we have shown previously that one channel can be activated in uninfected cells by exogenous protein kinase A. Here, we present evidence that in P. falciparum-infected red blood cells, a cAMP pathway modulates anion conductance of the erythrocyte membrane. In patch-clamp experiments on infected erythrocytes, addition of recombinant PfPKA-R to the pipette in vitro, or overexpression of PfPKA-R in transgenic parasites lead to down-regulation of anion conductance. Moreover, this overexpressing PfPKA-R strain has a growth defect that can be restored by increasing the levels of intracellular cAMP. Our data demonstrate that the anion channel is indeed regulated by a cAMP-dependent pathway in P. falciparum-infected red blood cells. The discovery of a parasite regulatory pathway responsible for modulating anion channel activity in the membranes of P. falciparum-infected red blood cells represents an important insight into how parasites modify host cell permeation pathways. These findings may also provide an avenue for the development of new intervention strategies targeting this important anion channel and its regulation. PMID:18248092

Merckx, Anaïs; Nivez, Marie-Paule; Bouyer, Guillaume; Alano, Pietro; Langsley, Gordon; Deitsch, Kirk; Thomas, Serge; Doerig, Christian; Egée, Stéphane

2008-01-01

132

Electron impact induced anion production in acetylene.  

PubMed

A detailed experimental investigation of electron induced anion production in acetylene, C2H2, in the energy range between 1 and 90 eV is presented. The anions are formed by two processes in this energy range: dissociative electron attachment (DEA) and dipolar dissociation (DD). DEA in C2H2 is found to lead to the formation of H(-) and C2(-)/C2H(-) through excitation of resonances in the electron energy range 1-15 eV. These anionic fragments are formed with super thermal kinetic energy and reveal no anisotropy in the angular distributions. DD in C2H2 leads to the formation of H(-), C(-)/CH(-) and C2(-)/C2H(-) with threshold energies of 15.7, 20.0 and 16.5 eV respectively. The measured anion yields have been used to calculate anion production rates for H(-), C(-)/CH(-) and C2(-)/C2H(-) in Titan's ionosphere. PMID:24343432

Szyma?ska, Ewelina; ?adež, Iztok; Krishnakumar, E; Mason, Nigel J

2014-02-28

133

Interactions of dietary cation-anion balance and phosphorus: effects on growth and serum inorganic phosphorus in dairy calves.  

PubMed

Thirty-six male and female Holstein and Jersey calves were assigned at weaning to a randomized complete block design in a 2 x 3 factorial arrangement to evaluate the influence of two dietary cation-anion balances (-14 and +39 meq(Na + K)-(Cl + S) per 100 g diet DM) and three amounts of dietary P (.22, .29, and .37%) on performance and P metabolism from 9 to 19 wk of age. Feed intake, average daily gain, and serum inorganic P were higher on the anionic diets and increased with increasing dietary P. Body weights were higher on the .37% P diets by wk 3 and on the anionic diets by wk 6. The interaction of dietary P and cation-anion balance was responsible for significant differences in calf performance; the anionic diet exhibited marked improvement over the cationic diet at the lowest P concentration. Results indicate that the availability of P for young dairy calves may be higher with anionic than cationic diets. PMID:3235736

Beighle, D E; Tucker, W B; Hemken, R W

1988-12-01

134

Bridging the Gap between Fluxomics and Industrial Biotechnology  

PubMed Central

Metabolic flux analysis is a vital tool used to determine the ultimate output of cellular metabolism and thus detect biotechnologically relevant bottlenecks in productivity. 13C-based metabolic flux analysis (13C-MFA) and flux balance analysis (FBA) have many potential applications in biotechnology. However, noteworthy hurdles in fluxomics study are still present. First, several technical difficulties in both 13C-MFA and FBA severely limit the scope of fluxomics findings and the applicability of obtained metabolic information. Second, the complexity of metabolic regulation poses a great challenge for precise prediction and analysis of metabolic networks, as there are gaps between fluxomics results and other omics studies. Third, despite identified metabolic bottlenecks or sources of host stress from product synthesis, it remains difficult to overcome inherent metabolic robustness or to efficiently import and express nonnative pathways. Fourth, product yields often decrease as the number of enzymatic steps increases. Such decrease in yield may not be caused by rate-limiting enzymes, but rather is accumulated through each enzymatic reaction. Fifth, a high-throughput fluxomics tool hasnot been developed for characterizing nonmodel microorganisms and maximizing their application in industrial biotechnology. Refining fluxomics tools and understanding these obstacles will improve our ability to engineer highlyefficient metabolic pathways in microbial hosts. PMID:21274256

Feng, Xueyang; Page, Lawrence; Rubens, Jacob; Chircus, Lauren; Colletti, Peter; Pakrasi, Himadri B.; Tang, Yinjie J.

2010-01-01

135

Crossing the Gap  

ERIC Educational Resources Information Center

In a nation where education is funded largely by local property taxes, schools in wealthy communities have plenty of funds to spend on programs that get their kids ready for college. Schools in poor communities scrimp and save to get the job done--or hope that funding from the state will help fill in the gap. This article describes how students…

Lockette, Tim

2009-01-01

136

Bridging the Gender Gap  

E-print Network

Bridging the Gender Gap: Growing the Next Generation of Women in Computing A sobering fact: the U need to ensure our research and development teams are diverse enough to anticipate, respond, and serve Develop: This radically new software development environment lets you write code for your phone on your

Chaudhuri, Surajit

137

Closing the Performance Gap.  

ERIC Educational Resources Information Center

Describes how the principal of a K-2, 400-student suburban elementary school near Flint, Michigan, worked with her staff and superintendent to develop and implement a strategic plan to close the student achievement gap. Reports significant improvement in reading and math scores after 1 year. (PKP)

Riggins, Cheryl G.

2002-01-01

138

Temperature Dependent Hybridization Gaps  

NASA Astrophysics Data System (ADS)

A number of heavy-fermion/mixed-valent materials show hybridization gaps either at the Fermi-energy or close to the Fermi-energy. In the former case, a heavy-fermion semiconducting state ensues and in the later case, the system remains metallic at low temperatures. In either case, the electronic structure is extremely temperature-dependent. It has been observed that the gap closes and the heavy quasiparticle bands disappear at high temperatures. The magnitude of the gaps scale with effective quasiparticle masses. A phenomenological model is presented that exhibits a temperature-dependence which is consistent with the above behavior. The model is based on a periodic array of Anderson impurities in which the electron correlations are represented by the coupling to bosons with an Einstein spectra. The model can be solved via systematic approximation. The solution describes the temperature- dependence of coherent and incoherent structures in the electronic excitation spectra. The predicted hybridization gaps for the metallic case are compared with data from photoemission experiments on UPd2Al3.

Riseborough, Peter

2011-03-01

139

Bridging the Gap.  

ERIC Educational Resources Information Center

Presents a critique of existing methodology used in curriculum updates in academic institutions, suggesting that an integrated approach is more realistic and meaningful to study and to bridging the gap between academic curriculum and industry's needs. Specifically recommends that curriculum-related and job-related data be analyzed simultaneously.…

Mansour, Ali H.; And Others

1986-01-01

140

An anionic surfactant for EOR applications  

NASA Astrophysics Data System (ADS)

This work is to investigate the new anionic surfactants for the Enhanced Oil Recovery (EOR) application. Sulfonated anionic surfactant was produced by attaching SO3 to an ethoxylated alcohol to increase the performance of the surfactant. Methallyl chloride and ethoxylated alcohol was reacted followed by the reaction with sodium bisulfite to produce anionic sulfonated surfactant in 80.3 % yield. The sulfonation reaction parameters such as reactants mole ratio, reaction temperature and catalyst amount were optimized. The generation and stability of foam from the synthesized surfactant is also tested and results are reported. The synthesized novel surfactant was further investigated for the effect on the CO2 mobility in porous media and the findings are presented here. This in house developed surfactant has a great potential for CO2- EOR applications.

Sagir, Muhammad; Tan, Isa M.; Mushtaq, Muhammad

2014-10-01

141

Metabolism Roundup  

NSDL National Science Digital Library

Laboratory rats with large amounts of type II muscle fiber, maintained health for a longer period of time. In addition, those fed artificial sweetener tended to slow down their metabolism and show weight gain.

Science Update (AAAS; )

2008-02-29

142

Metabolic Syndrome  

MedlinePLUS

... to manage your condition. Medications can also treat risk factors such as high blood pressure or high blood glucose. If you think you have risk factors for the metabolic syndrome, talk with your doctor. ...

143

Metabolic acidosis  

MedlinePLUS

Arterial blood gas Serum electrolytes Urine pH Arterial blood gas analysis and a serum electrolytes test (such as a basic metabolic panel) will confirm acidosis is present and determine whether it is ...

144

Metabolic Engineering  

Microsoft Academic Search

\\u000a \\u000a The metabolic engineering of primary metabolism provides an enormous potential to improve the value of plant-based raw materials\\u000a for food and industrial applications. This chapter focuses on the current progress in the manipulation of carbohydrate and\\u000a lipid biosynthesis in transgenic starch and oilseed crops, respectively. In most approaches, the manipulation of the biosynthetic\\u000a routes revealed limitations and bottlenecks in the

Lars M. Voll; Frederik Börnke

145

Templating irreversible covalent macrocyclization by using anions.  

PubMed

Inorganic anions were used as templates in the reaction between a diamine and an activated diacid to form macrocyclic amides. The reaction conditions were found to perform the macrocyclization sufficiently slow to observe a template effect. A number of analytical methods were used to clarify the reaction mechanisms and to show that the structure of the intermediate plays a decisive role in determining the product distribution. For the macrocyclization under kinetic control, it was shown that the amount of a template, the conformational rigidity of building blocks, and the anion affinities of reaction components and intermediates are important parameters that one should take into consideration to achieve high yields. PMID:23364908

Kataev, Evgeny A; Kolesnikov, Grigory V; Arnold, Rene; Lavrov, Herman V; Khrustalev, Victor N

2013-03-11

146

Photoelectron spectroscopy and theoretical studies of anion-? interactions: binding strength and anion specificity.  

PubMed

Proposed in theory and then their existence confirmed, anion-? interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, anion-? interaction strengths that are free from complications of condensed-phase environments have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic, was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl(-), Br(-), I(-), linear thiocyanate SCN(-), trigonal planar nitrate NO3(-), pyramidic iodate IO3(-), and tetrahedral sulfate SO4(2-)). The binding energies of the resultant gaseous 1?:?1 complexes (1·Cl(-), 1·Br(-), 1·I(-), 1·SCN(-), 1·NO3(-), 1·IO3(-) and 1·SO4(2-)) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion-specific effects. The binding strengths of Cl(-), NO3(-), IO3(-) with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal mol(-1), but only about 40% of that between 1 and SO4(2-). Quantum chemical calculations reveal that all the anions reside in the center of the cavity of 1 with an anion-? binding motif in the complexes' optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and charge distribution analyses further support anion-? binding formation. The calculated binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work illustrates that size-selective photoelectron spectroscopy combined with theoretical calculations represents a powerful technique to probe anion-? interactions and has potential to provide quantitative guest-host molecular binding strengths and unravel fundamental insights in specific anion recognitions. PMID:25515705

Zhang, Jian; Zhou, Bin; Sun, Zhen-Rong; Wang, Xue-Bin

2015-02-01

147

GAP-REACH  

PubMed Central

Growing awareness of health and health care disparities highlights the importance of including information about race, ethnicity, and culture (REC) in health research. Reporting of REC factors in research publications, however, is notoriously imprecise and unsystematic. This article describes the development of a checklist to assess the comprehensiveness and the applicability of REC factor reporting in psychiatric research publications. The 16-itemGAP-REACH© checklist was developed through a rigorous process of expert consensus, empirical content analysis in a sample of publications (N = 1205), and interrater reliability (IRR) assessment (N = 30). The items assess each section in the conventional structure of a health research article. Data from the assessment may be considered on an item-by-item basis or as a total score ranging from 0% to 100%. The final checklist has excellent IRR (? = 0.91). The GAP-REACH may be used by multiple research stakeholders to assess the scope of REC reporting in a research article. PMID:24080673

Lewis-Fernández, Roberto; Raggio, Greer A.; Gorritz, Magdaliz; Duan, Naihua; Marcus, Sue; Cabassa, Leopoldo J.; Humensky, Jennifer; Becker, Anne E.; Alarcón, Renato D.; Oquendo, María A.; Hansen, Helena; Like, Robert C.; Weiss, Mitchell; Desai, Prakash N.; Jacobsen, Frederick M.; Foulks, Edward F.; Primm, Annelle; Lu, Francis; Kopelowicz, Alex; Hinton, Ladson; Hinton, Devon E.

2015-01-01

148

Photonic Band Gap  

NSDL National Science Digital Library

Created by Boyang Liu and Professor Seng-Tiong Ho at Northwestern University, and presented by the NanoEd Resource Portal, this site covers the concept of the photonic band gap. Here, visitors will find a basic description of the concept, ideas of how to incorporate it into classroom activities, and a user's manual to walk students step-by-step through the concept. There is also a link to an interactive simulation (the link is labeled Open Visualization), which allows students to adjust the wavelength and color of the light source, particle size, and incident angle to view changes to the photonic band gap. This is a thorough and useful resource for any nanotechnology classroom.

Ho, Seng-Tiong

149

Photoelectron spectroscopic studies of 5-halouracil anions  

NASA Astrophysics Data System (ADS)

The parent negative ions of 5-chlorouracil, UCl- and 5-fluorouracil, UF- have been studied using anion photoelectron spectroscopy in order to investigate the electrophilic properties of their corresponding neutral halouracils. The vertical detachment energies (VDE) of these anions and the adiabatic electron affinities (EA) of their neutral molecular counterparts are reported. These results are in good agreement with the results of previously published theoretical calculations. The VDE values for both UCl- and UF- and the EA values for their neutral molecular counterparts are much greater than the corresponding values for both anionic and neutral forms of canonical uracil and thymine. These results are consistent with the observation that DNA is more sensitive to radiation damage when thymine is replaced by halouracil. While we also attempted to prepare the parent anion of 5-bromouracil, UBr-, we did not observe it, the mass spectrum exhibiting only Br- fragments, i.e., 5-bromouracil apparently underwent dissociative electron attachment. This observation is consistent with a previous assessment, suggesting that 5-bromouracil is the best radio-sensitizer among these three halo-nucleobases.

Radisic, Dunja; Ko, Yeon Jae; Nilles, John M.; Stokes, Sarah T.; Sevilla, Michael D.; Rak, Janusz; Bowen, Kit H.

2011-01-01

150

Anion-Conducting Polymer, Composition, and Membrane  

DOEpatents

Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

2008-10-21

151

Photoelectron spectroscopic studies of 5-halouracil anions  

SciTech Connect

The parent negative ions of 5-chlorouracil, UCl{sup -} and 5-fluorouracil, UF{sup -} have been studied using anion photoelectron spectroscopy in order to investigate the electrophilic properties of their corresponding neutral halouracils. The vertical detachment energies (VDE) of these anions and the adiabatic electron affinities (EA) of their neutral molecular counterparts are reported. These results are in good agreement with the results of previously published theoretical calculations. The VDE values for both UCl{sup -} and UF{sup -} and the EA values for their neutral molecular counterparts are much greater than the corresponding values for both anionic and neutral forms of canonical uracil and thymine. These results are consistent with the observation that DNA is more sensitive to radiation damage when thymine is replaced by halouracil. While we also attempted to prepare the parent anion of 5-bromouracil, UBr{sup -}, we did not observe it, the mass spectrum exhibiting only Br{sup -} fragments, i.e., 5-bromouracil apparently underwent dissociative electron attachment. This observation is consistent with a previous assessment, suggesting that 5-bromouracil is the best radio-sensitizer among these three halo-nucleobases.

Radisic, Dunja; Ko, Yeon Jae; Nilles, John M.; Stokes, Sarah T.; Bowen, Kit H. [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Sevilla, Michael D. [Department of Chemistry, Oakland University, Rochester, Michigan 48309 (United States); Rak, Janusz [Department of Chemistry, University of Gdansk, 80-952 Gdansk (Poland)

2011-01-07

152

Anion-conducting polymer, composition, and membrane  

DOEpatents

Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

2011-11-22

153

Anion-conducting polymer, composition, and membrane  

DOEpatents

Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

2010-12-07

154

SIMULATING METABOLISM OF XENOBIOTIC CHEMICALS AS A PREDICTOR OF TOXICITY  

EPA Science Inventory

EPA is faced with long lists of chemicals that need to be assessed for hazard. A major gap in evaluating chemical risk is accounting for metabolic activation resulting in increased toxicity. The goals of this project are to develop a capability to forecast the metabolism of xenob...

155

SUPRAMOLECULAR CHEMISTRY OF SELECTIVE ANION RECOGNITION FOR ANIONS OF ENVIRONMENTAL RELEVANCE  

EPA Science Inventory

The supramolecular chemistry of selective anion recognition by synthetic polyammonium macrocycles will be explored in a comprehensive, long term program designed to provide new solutions to problems critical to the environmental initiative of DOE. Highly shape- and charge selecti...

156

Temperature Dependence of the Mitochondrial Inner Membrane Anion Channel  

E-print Network

(reviewed in Ref. 1). In view of the variety of anions transported and the fact that, under physiological of the potassium ionophore valinomycin to mitochon- dria suspended in potassium salts of the test anion (1

Abraham, Nader G.

157

Synthesis of Anion Exchange Polystyrene Membranes for the Electrolysis of  

E-print Network

Synthesis of Anion Exchange Polystyrene Membranes for the Electrolysis of Sodium Chloride Sonny composite membrane for the electrolysis of sodium chloride to produce sodium hydroxide by selective re: anion exchange membrane, membrane electrolysis, polystyrene Introduction Electrodialysis is a mass

Singh, Jayant K.

158

Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance  

SciTech Connect

The major thrust of this project, led by the University of Kansas (Prof. Kristin Bowman-James), entails an exploration of the basic determinants of anion recognition and their application to the design, synthesis, and testing of novel sulfate extractants. A key scientific inspiration for the work comes from the need, codified in simple-to-appreciate terms by the Oak Ridge National Laboratory component of the team (viz. Dr. Bruce Moyer), for chemical entities that can help in the extractive removal of species that have low solubilities in borosilicate glass. Among such species, sulfate anion, has been identified as particularly insidious. Its presence interferes with the vitrification process, thus rendering the remediation of tank waste from, e.g., the Hanford site far more difficult and expensive. The availability of effective extractants, that would allow for the separation of separating sulfate from the major competing anions in the waste, especially nitrate, could allow for pre-vitrification removal of sulfate via liquid-liquid extraction. The efforts at The University of Texas, the subject of this report, have thus concentrated on the development of new sulfate receptors. These systems are designed to increase our basic understanding of anion recognition events and set the stage for the development of viable sulfate anion extractants. In conjunction with the Oak Ridge National Laboratory (ORNL) members of the research team, several of these new receptors were studied as putative extractants, with two of the systems being shown to act as promising synergists for anion exchange.

Jonathan L. Sessler

2007-09-21

159

Detection of Perchlorate Anion on Functionalized Silver Colloids Using Surface-Enhanced Raman Scattering  

SciTech Connect

Perchlorate anion interferes with the uptake of iodide by the human thyroid gland and consequently disrupts the regulation of metabolism. Chronic exposure to high levels of perchlorate may lead to the formation of thyroid gland tumors. Although the Environmental Protection Agency (EPA) has not set a maximum contaminant level (MCL) for perchlorate, a draft drinking water range of 4-18 ppb based on 2 liter daily consumption of water has been established. The current EPA approved method for detecting perchlorate uses ion chromatography which has a detection limit of ~1ppb and involves lengthy analytical time in the laboratory. A unique combination of the surface-enhanced Raman scattering (SERS) effect and the bifunctional anion exchange resin’s high selectivity may provide an alternative way to detect perchlorate at such low concentrations and with high specificity. SERS, which uses laser excitation of adsorbed perchlorate anions on silver nanoparticles, has been shown to detect perchlorate anions at concentrations as low as 50 ppb. Normal micro-Raman analysis of perchlorate sorbed onto the resin beads has detected an even lower concentration of 10 ppb. In an effort to integrate these two effects, silver nanoparticles were coated with N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride, a functional group similar to that found on the resin bead, and subsequently inserted into different perchlorate concentration environments. This method has resulted in perchlorate detection down to ~10 ppb and a more consistent detection of perchlorate anion at ~50 ppb than that of earlier methods. As suggested by the direct insertion of functionalized silver colloids into perchlorate samples, this technique may potentially allow for the development of a probe using on-site Raman spectrometry to detect significantly low concentrations of perchlorate in situ rather than in the laboratory.

Tio, J.; Wang, W.; Gu, B.

2005-01-01

160

Stable and highly persistent quinoxaline-centered metalloorganic radical anions: preparation, structural, spectroscopic, and computational investigations.  

PubMed

Coordination of diazines such as quinoxaline to transition metals stabilizes radical anions generated by chemical or electrochemical cathodic reduction. However, even though various sorts of radical anionic diazines have been subjected to spectroscopic investigations in the recent past, reports combining structural, solid-state electron paramagnetic resonance (EPR) and computational investigations of kinetically stable species are still missing. In this study, four radical anions derived from tricarbonylmanganese- and tricarbonylrhenium-bound quinoxaline chelates, embedded within a triple-decker architecture, have been prepared from neutral substrates by chemical reduction over alkaline metals (K, Rb); the electronic structure of the latter metalloorganic paramagnetic salts was investigated by the means of structural X-ray diffraction analysis, electrochemistry, solution and crystal EPR spectroscopy, and density functional theory (DFT). Unprecedented structures of three manganese-bound and one rhenium-bound quinoxaline-derived paramagnetic salts were obtained from solutions of the corresponding radical anions crystallized in the presence of cryptand 222. It is inferred from a comparative study of the structures of anionic and neutral quinoxaline complexes that reduction does not have any significant impact over the coordination mode of the metal centers and over the overall geometry of the triple-decker architecture. The most notable changes in the radical-anionic metalloorganic species, as compared to the neutral parent molecules, comprise a slight hapticity shift of the metal-bound benzyl moiety and a weak intraannular distortion of the quinoxalyl core. Single-crystal EPR experiments carried out with the rhenium and manganese compounds produced the respective anisotropic g tensor, which was found in each case to be essentially located at the quinoxalyl fragment. Computations, carried out using DFT methods (B3LYP-LANL2DZ and Becke-Perdew-TZP), corroborated the features suggested by structural analysis. Single-point calculation using the B3LYP functional and various basis sets [LANL2DZ, 6-31G(d), 6-311+G(d), and 6-311+G(2d,p)] provided us with values of anisotropic g tensors and hyperfine coupling constants consistent with those determined experimentally. It is inferred from this study that the two metal centers bound to the nitrogen atoms of the quinoxalyl core contribute in the lowering of the HOMO-LUMO gap in the neutral species. The triple-decker arrangement, which combines chelation of the metal, steric protection, and encapsulation of the central quinoxalyl core, is a stabilizing factor that provides a long-lived character to the radical-anionic species. PMID:19053841

Choua, Sylvie; Djukic, Jean-Pierre; Dalléry, Jérôme; Bieber, André; Welter, Richard; Gisselbrecht, Jean-Paul; Turek, Philippe; Ricard, Louis

2009-01-01

161

Effect of Dietary Cation-Anion Difference and Dietary Crude Protein on Milk Yield, AcidBase Chemistry, and Rumen Fermentation  

Microsoft Academic Search

Eight primiparous lactating Holstein cows (47 ± 10 d in milk) fitted with ruminal cannulae were used to determine the effect of dietary cation-anion difference (DCAD) and dietary crude protein (CP) concentration onmilkyieldandcomposition,acid-basechemistry,and measures of N metabolism in lactating dairy cows. Treatments were arranged as a 2 × 2 factorial in a randomized complete block design to provide 15 or

C. D. Wildman; J. W. West; J. K. Bernard

2007-01-01

162

Mind the gap  

E-print Network

In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

M. S. Bhagwat; A. Krassnigg; P. Maris; C. D. Roberts

2006-12-06

163

Miscibility Gap Systems  

NASA Technical Reports Server (NTRS)

Immiscible droplets embedded in a host fluid in which a temperature gradient exists migrate toward the hot end of the host fluid because of the temperature dependence of the interfacial energy of the droplet. This thermocapillary migration effect was exploited in the design of a controllable heat valve which is the thermal analog of the electronic vacuum triode. Studies have also been made of test cells that could use thermocapillary migration to facilitate the study of condensation and dissolution kinetics in miscibility-gap solutions.

Schmid, L. A.

1985-01-01

164

Closing the stop gap  

E-print Network

Light stops are a hallmark of the most natural realizations of weak-scale supersymmetry. While stops have been extensively searched for, there remain open gaps around and below the top mass, due to similarities of stop and top signals with current statistics. We propose a new fast-track avenue to improve light stop searches for R-parity conserving supersymmetry, by comparing top cross section measurements to the theoretical prediction. Stop masses below ~ 180 GeV can now be ruled out for a light neutralino. The possibility of a stop signal contaminating the top mass measurement is also briefly addressed.

Michal Czakon; Alexander Mitov; Michele Papucci; Joshua T. Ruderman; Andreas Weiler

2014-07-03

165

Metabolic analysis.  

PubMed

Analysis of the metabolome with coverage of all of the possibly detectable components in the sample, rather than analysis of each individual metabolite at a given time, can be accomplished by metabolic analysis. Targeted and/or nontargeted approaches are applied as needed for particular experiments. Monitoring hundreds or more metabolites at a given time requires high-throughput and high-end techniques that enable screening for relative changes in, rather than absolute concentrations of, compounds within a wide dynamic range. Most of the analytical techniques useful for these purposes use GC or HPLC/UPLC separation modules coupled to a fast and accurate mass spectrometer. GC separations require chemical modification (derivatization) before analysis, and work efficiently for the small molecules. HPLC separations are better suited for the analysis of labile and nonvolatile polar and nonpolar compounds in their native form. Direct infusion and NMR-based techniques are mostly used for fingerprinting and snap phenotyping, where applicable. Discovery and validation of metabolic biomarkers are exciting and promising opportunities offered by metabolic analysis applied to biological and biomedical experiments. We have demonstrated that GC-TOF-MS, HPLC/UPLC-RP-MS and HILIC-LC-MS techniques used for metabolic analysis offer sufficient metabolome mapping providing researchers with confident data for subsequent multivariate analysis and data mining. PMID:19488710

Tolstikov, Vladimir V

2009-01-01

166

Metabolic Syndrome  

MedlinePLUS

... Web version Metabolic Syndrome Overview What is insulin resistance? Your body changes most of the food you eat into glucose (a form of sugar). Insulin is a hormone produced by the pancreas that allows ... as insulin resistance. If you have insulin resistance, your body will ...

167

Mitochondrial voltage-dependent anion channel gene family in Drosophila melanogaster: Complex patterns of evolution, genomic organization, and developmental expression  

Microsoft Academic Search

Voltage-dependent anion channels (VDACs), also known as mitochondrial porins, are a family of small pore-forming proteins of the mitochondrial outer membrane found in all eukaryotes. VDACs play important roles in the regulated flux of metabolites between the cytosolic and mitochondrial compartments, energy metabolism, and apoptosis. Annotation of the genome sequence of Drosophila melanogaster revealed three genes (CG17137, CG31722-A, and CG31722-B)

Brett H. Graham; William J. Craigen

2005-01-01

168

Closing gaps: linking elements that control stomatal movement.  

PubMed

Stomata are an attractive experimental system in plant biology, because the responses of guard cells to environmental signals can be directly linked to changes in the aperture of stomatal pores. In this review, the mechanics of stomatal movement are discussed in relation to ion transport in guard cells. Emphasis is placed on the ion pumps, transporters, and channels in the plasma membrane, as well as in the vacuolar membrane. The biophysical properties of transport proteins for H(+), K(+), Ca(2+), and anions are discussed and related to their function in guard cells during stomatal movements. Guard cell signaling pathways for ABA, CO2, ozone, microbe-associated molecular patterns (MAMPs) and blue light are presented. Special attention is given to the regulation of the slow anion channel (SLAC) and SLAC homolog (SLAH)-type anion channels by the ABA signalosome. Over the last decade, several knowledge gaps in the regulation of ion transport in guard cells have been closed. The current state of knowledge is an excellent starting point for tackling important open questions concerning stress tolerance in plants. PMID:24800691

Kollist, Hannes; Nuhkat, Maris; Roelfsema, M Rob G

2014-07-01

169

Anion photoelectron spectroscopy of radicals and clusters  

SciTech Connect

Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying {sup 2}{Sigma} and {sup 2}{Pi} states of C{sub 2n}H (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C{sub 2}H and C{sub 4}H. Other radicals studied include NCN and I{sub 3}. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I{sub 3} revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

Travis, Taylor R.

1999-12-16

170

Aza crown ether compounds as anion receptors  

DOEpatents

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI{sup +} ion in alkali metal batteries. 3 figs.

Lee, H.S.; Yang, X.O.; McBreen, J.

1998-08-04

171

Aza crown ether compounds as anion receptors  

DOEpatents

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

1998-08-04

172

Deuterium anions in inertial electrostatic confinement devices  

Microsoft Academic Search

A magnetic deflection-energy analyzer and Faraday trap diagnostic have been used to make measurements of divergent deuterium anion flow in the inertial electrostatic confinement experiment at the University of Wisconsin-Madison (UW-IEC) [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, I. E. Radel, and A.

D. R. Boris; E. Alderson; G. Becerra; D. C. Donovan; B. Egle; G. A. Emmert; L. Garrison; G. L. Kulcinski; J. F. Santarius; C. Schuff; S. J. Zenobia

2009-01-01

173

Models of environmental effects on anion polarizability  

NASA Astrophysics Data System (ADS)

This paper deals with three different approaches to the representation of environmental effects on anion polarizability in cubic crystals of the stoichiometry MX, where M is an alkali metal and X is a halogen. Ab initio embedded cluster calculations of the variation in anion polarizability with pressure in a fixed crystal type are presented and compared with experiment. The results are then used in a scaled ab initio model used to predict further values for the pressure dependence of the in-crystal anion polarizability. This scaled model is compared with a fully empirical 'universal' model due to Batana et al. based on polarizability change with ionic radius [1997, Molec. Phys. , 92, 1029]. The assumptions of the two models differ substantially and the central purpose of this paper is to contrast these differences and highlight their consequences for prediction. Although the empirical model typically overestimates the experimental pressure derivatives, and the ab initio calculations somewhat underestimate them, it is shown that the assumption of incompressible cations in the scaled ab initio -derived model has a firmer physical basis than the empirical picture in which all ions are compressible.

Wilson, M.; Madden, P. A.; Jemmer, P.; Fowler, P. W.; Batana, A.; Bruno, J.; Munn, R. W.; Monard, M. C.

174

Safe 5-nitrotetrazolate anion transfer reagents.  

PubMed

Silver 5-nitrotetrazolate (1) and copper(ii) 5-nitrotetrazolate 5-nitrotetrazole dihydrate (2) are useful reagents for the synthesis of 5-nitrotetrazole (NT) salts. Both compounds were synthesized and characterized by vibrational spectroscopy (IR and Raman) and differential scanning calorimetry (DSC). In addition, their sensitivity towards friction, shock and electrostatic discharge was tested by standard BAM methods. The extremely high sensitivity of both materials makes the transfer of the NT(-) anion using and hazardous and not suitable for up-scaling. In order to diminish the hazards involved with the transfer of the energetic anion and to render the synthesis of NT salts suitable for an industrial scale the two compounds were stabilized by coordination with a chelating ligand and silver(ethylendiamine) 5-nitrotetrazolate and bis(ethylendiamine)copper(ii) 5-nitrotetrazolate were synthesized in high yields. Both the stabilized NT(-) anion transfer reagents were characterized by analytical and spectroscopic methods. In addition, the crystal structure of the ethylendiamine copper complex was determined: orthorombic, Pbca; a = 7.5200(1), b = 14.0124(2), c = 14.7740(2) A; V = 1556.78(4) A(3). Furthermore, we synthesized triaminocopper(ii) 5-nitrotetrazolate, which has potential as a more environmentally-friendly primary explosive. Lastly, the synthetic potential of the ethylediamine adducts and to form energetic salts of NT was investigated. PMID:19240919

Klapötke, Thomas M; Sabaté, Carles Miró

2009-03-14

175

Hydrogen sulfide anion regulates redox signaling via electrophile sulfhydration  

PubMed Central

An emerging aspect of redox signaling is the pathway mediated by electrophilic byproducts, such as nitrated cyclic nucleotide (for example, 8-nitroguanosine 3?,5?-cyclic monophosphate (8-nitro-cGMP)) and nitro or keto derivatives of unsaturated fatty acids, generated via reactions of inflammation-related enzymes, reactive oxygen species, nitric oxide and secondary products. Here we report that enzymatically generated hydrogen sulfide anion (HS?) regulates the metabolism and signaling actions of various electrophiles. HS? reacts with electrophiles, best represented by 8-nitro-cGMP, via direct sulfhydration and modulates cellular redox signaling. The relevance of this reaction is reinforced by the significant 8-nitro-cGMP formation in mouse cardiac tissue after myocardial infarction that is modulated by alterations in HS? biosynthesis. Cardiac HS?, in turn, suppresses electrophile-mediated H-Ras activation and cardiac cell senescence, contributing to the beneficial effects of HS? on myocardial infarction–associated heart failure. Thus, this study reveals HS?-induced electrophile sulfhydration as a unique mechanism for regulating electrophile-mediated redox signaling. PMID:22772154

Nishida, Motohiro; Sawa, Tomohiro; Kitajima, Naoyuki; Ono, Katsuhiko; Inoue, Hirofumi; Ihara, Hideshi; Motohashi, Hozumi; Yamamoto, Masayuki; Suematsu, Makoto; Kurose, Hitoshi; van der Vliet, Albert; Freeman, Bruce A; Shibata, Takahiro; Uchida, Koji; Kumagai, Yoshito; Akaike, Takaaki

2014-01-01

176

Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies  

NASA Astrophysics Data System (ADS)

We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)-, measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP/6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the ?* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue.

Chomicz, Lidia; Rak, Janusz; Paneth, Piotr; Sevilla, Michael; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H.

2011-09-01

177

Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies  

PubMed Central

We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)?, measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP/6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the ?* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue. PMID:21950856

Chomicz, Lidia; Rak, Janusz; Paneth, Piotr; Sevilla, Michael; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H.

2011-01-01

178

Filling the launch gap  

NASA Astrophysics Data System (ADS)

Vehicles proposed to fill the gap in the U.S. space program's space transport needs for the next decade resulting from the January Challenger disaster, are discussed. Prior to the accident, the Air Force planned to purchase a Complementary Expendable Launch Vehicle system consisting of 10 single-use Titan-34D7 rockets. Another heavy lift booster now considered is the Phoenix H. Commercial launch vehicle systems projected to be available in the necessary time frame include the 215,000-pound thrust 4000-pound LEO payload capacity NASA Delta, the 11,300-pound LEO payload capacity Atlas Centaur the first ICBM, and the all-solid propellant expendable 2000-pound LEO payload Conestoga rocket. Also considered is the man-rated fully reusable Phoenix vertical take-off and vertical-landing launch vehicle.

Hoeser, S.

1986-05-01

179

An Innovative Anion Regulation Strategy for Energy Bands of Semiconductors: A Case from Bi2O3 to Bi2O(OH)2SO4  

NASA Astrophysics Data System (ADS)

How to develop a new, efficient photo catalyst is still a big challenge to us. A suitable band gap is the key for light absorption of semiconductor. Herein, an innovative anion intercalation strategy is, for the first time, developed to regulate the energy band of semiconductor. Typically, we introduce a layered sulfate compound (Bi2O(OH)2SO4) as a new photo catalyst, which has not been known before. Both partial density of states (PDOS) and total density of states (TDOS) have demonstrated that compared with Bi2O3 (2.85 eV), the band gap of Bi2O(OH)2SO4 has been widened to 4.18 eV by the intercalation of sulfate anion. Moreover, the band gap width of oxyacid salt compound is mainly predominated by the number of the outmost electrons (NOE) of central atom of anion. This study suggests that new photo catalysts can be developed by grouping anions with the existing oxides or sulfides.

Tian, Hao; Teng, Fei; Xu, Juan; Lou, Sunqi; Li, Na; Zhao, Yunxuan; Chen, Mindong

2015-01-01

180

An Innovative Anion Regulation Strategy for Energy Bands of Semiconductors: A Case from Bi2O3 to Bi2O(OH)2SO4  

PubMed Central

How to develop a new, efficient photo catalyst is still a big challenge to us. A suitable band gap is the key for light absorption of semiconductor. Herein, an innovative anion intercalation strategy is, for the first time, developed to regulate the energy band of semiconductor. Typically, we introduce a layered sulfate compound (Bi2O(OH)2SO4) as a new photo catalyst, which has not been known before. Both partial density of states (PDOS) and total density of states (TDOS) have demonstrated that compared with Bi2O3 (2.85?eV), the band gap of Bi2O(OH)2SO4 has been widened to 4.18?eV by the intercalation of sulfate anion. Moreover, the band gap width of oxyacid salt compound is mainly predominated by the number of the outmost electrons (NOE) of central atom of anion. This study suggests that new photo catalysts can be developed by grouping anions with the existing oxides or sulfides. PMID:25597769

Tian, Hao; Teng, Fei; Xu, Juan; Lou, Sunqi; Li, Na; Zhao, Yunxuan; Chen, Mindong

2015-01-01

181

An Innovative Anion Regulation Strategy for Energy Bands of Semiconductors: A Case from Bi2O3 to Bi2O(OH)2SO4.  

PubMed

How to develop a new, efficient photo catalyst is still a big challenge to us. A suitable band gap is the key for light absorption of semiconductor. Herein, an innovative anion intercalation strategy is, for the first time, developed to regulate the energy band of semiconductor. Typically, we introduce a layered sulfate compound (Bi2O(OH)2SO4) as a new photo catalyst, which has not been known before. Both partial density of states (PDOS) and total density of states (TDOS) have demonstrated that compared with Bi2O3 (2.85?eV), the band gap of Bi2O(OH)2SO4 has been widened to 4.18?eV by the intercalation of sulfate anion. Moreover, the band gap width of oxyacid salt compound is mainly predominated by the number of the outmost electrons (NOE) of central atom of anion. This study suggests that new photo catalysts can be developed by grouping anions with the existing oxides or sulfides. PMID:25597769

Tian, Hao; Teng, Fei; Xu, Juan; Lou, Sunqi; Li, Na; Zhao, Yunxuan; Chen, Mindong

2015-01-01

182

Cellular Metabolism  

NSDL National Science Digital Library

This is a lesson about the evidence for life on other planets. Learners will play a game to examine processes in cellular metabolism and explore both direct and indirect evidence for fingerprints of life. Includes teacher notes, learning objectives, and assessment of prior knowledge and preconceptions. This is Lesson 2 in Exploring Deep-Subsurface Life. Earth Analogues for Possible Life on Mars: Lessons and Activities.

2012-12-06

183

Metabolic Downregulation  

PubMed Central

Background and Purpose The search for effective neuroprotectants remains frustrating, particularly with regard to specific pharmaceuticals. However, laboratory studies have consistently shown remarkable neuroprotection with 2 nonpharmacological strategies—therapeutic hypothermia and ischemic preconditioning. Recent studies have shown that the mechanism of protection underlying both of these treatments is correlated to downregulation of cellular and tissue metabolism. Thus, understanding the mechanisms underlying such robust protective effects could lead to appropriate translation at the clinical level. In fact, hypothermia is already being used at many centers to improve neurological outcome from cardiac arrest. Methods A systematic review of both topics is presented in terms of underlying pathophysiological mechanisms and application at the clinical level. Results Although the mechanisms of protection for both therapeutic strategies are multifold, both share features of downregulating metabolism. Both therapeutic strategies are robust neuroprotectants, but translating them to the clinical arena is challenging, though not impossible, and clinical studies have shown or suggest benefits of both treatments. Conclusions The strategy of metabolic downregulation should be further explored to identify effective neuroprotectants that can be easily applied clinically. PMID:18658035

Yenari, Midori; Kitagawa, Kazuo; Lyden, Patrick; Perez-Pinzon, Miguel

2008-01-01

184

Gap and stripline combined monitor  

DOEpatents

A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility is disclosed. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length. 4 figs.

Yin, Y.

1986-08-19

185

Observation of polychromatic gap solitons  

E-print Network

theoretically and observe experimentally poly- chromatic gap solitons generated by supercontinuum light-induced broadening and color separation to the simultaneous spatio-spectral localization of supercontinuum light

186

Cell Metabolism Postprandial Hepatic Lipid Metabolism  

E-print Network

Cell Metabolism Article Postprandial Hepatic Lipid Metabolism Requires Signaling through Akt2 in the absence of Akt2. These data show that insulin signaling through Akt2 promotes anabolic lipid metabolism. Sabatini,2,3,4,5 and Morris J. Birnbaum1,* 1The Institute of Diabetes, Obesity, and Metabolism, University

Sabatini, David M.

187

Confocal imaging of organic anion transport in intact rat choroid plexus.  

PubMed

We used confocal microscopy and quantitative image analysis to follow the movement of the fluorescent organic anion fluorescein (FL) from bath to cell and cell to blood vessel in intact rat lateral choroid plexus. FL accumulation in epithelial cells and underlying vessels was rapid, concentrative, and reduced by other organic anions. At steady state, cell fluorescence exceeded bath fluorescence by a factor of 3-5, and vessel fluorescence exceeded cell fluorescence by a factor of approximately 2. In cells, FL distributed between diffuse and punctate compartments. Cell and vessel accumulation of FL decreased when metabolism was inhibited by KCN, when bath Na(+) was reduced from 130 to 26 mM, and when the Na(+) gradient was collapsed with ouabain. Cell and vessel accumulation increased by >50% when 1-10 microM glutarate was added to the bath. Finally, transport of FL and carboxyfluorescein (generated intracellularly from carboxyfluorescein diacetate) from cell to blood vessel was greatly diminished when medium K(+) concentration ([K(+)]) was increased 10-fold. These results 1) validate a new approach to the study of choroid plexus function, and 2) indicate a two-step mechanism for transepithelial organic anion transport: indirect coupling of uptake to Na(+) at the apical membrane and electrical potential-driven efflux at the basolateral membrane. PMID:11934698

Breen, Christopher M; Sykes, Destiny B; Fricker, Gert; Miller, David S

2002-05-01

188

Anion binding behavior of heterocycle-strapped calix[4]pyrroles.  

PubMed

A comparative study of the halide and benzoate anion binding properties of a series of phenyl, pyrrole, and furan-strapped calix[4]pyrroles has been carried out. These receptors, which have previously been shown to bind the chloride anion (Yoon et al., Angew. Chem., Int. Ed. 47(27):5038-5042, 2008), were found to bind bromide and benzoate anion (studied as the corresponding tetrabutyl-ammonium salts) with near equal affinity in acetonitrile, albeit less well than chloride, as determined from ITC measurements or NMR spectroscopic titrations. This stands in marked contrast to the parent octamethylcalix[4]pyrrole, where the carboxylate anion affinities are substantially higher than those for bromide anion under identical conditions. This finding is rationalized in terms of tighter binding cavity present in the strapped systems. For all three anions for which quantitative data could be obtained (i.e., Cl(-), Br(-), PhCO(2) (-)), the pyrrole-strapped system displayed the highest affinity, although the relative enhancement was found to depend on the anion in question. In the specific case of fluoride anion binding to the pyrrole-strapped receptor, two modes of interaction are inferred, with the first consisting of binding to the calix[4]pyrrole via NH-anion hydrogen bonds, followed by a process that involves deprotonation of the strapped pyrrolic NH proton. A single crystal X-ray diffraction analysis provides support for the first of these modes and further reveals the presence of a methanol molecule bound to the fluoride anion. PMID:21218134

Gross, Dustin E; Yoon, Dae-Wi; Lynch, Vincent M; Lee, Chang-Hee; Sessler, Jonathan L

2010-02-01

189

Bimolecular Nucleophilic Substitution of an Anion by an Anion. A Theoretical Study of Phenylboronic Acids as a Source of Phenyl Anions.  

E-print Network

Acids as a Source of Phenyl Anions. Nathan Knotts and Rainer Glaser* Department of Chemistry, University of Missouri­Columbia, Columbia, MO 65211 Phenylboronic acid, 1, is a source of reactive phenyl anions of phenylboronic acid with strong nucleophiles, such as hydroxide ion, leads to the formation of B(OH)4

Glaser, Rainer

190

Sodium Bicarbonate Therapy in Patients with Metabolic Acidosis  

PubMed Central

Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated. PMID:25405229

Adeva-Andany, María M.; Fernández-Fernández, Carlos; Mouriño-Bayolo, David; Castro-Quintela, Elvira; Domínguez-Montero, Alberto

2014-01-01

191

Sodium bicarbonate therapy in patients with metabolic acidosis.  

PubMed

Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated. PMID:25405229

Adeva-Andany, María M; Fernández-Fernández, Carlos; Mouriño-Bayolo, David; Castro-Quintela, Elvira; Domínguez-Montero, Alberto

2014-01-01

192

Structural evolution of small ruthenium cluster anions  

NASA Astrophysics Data System (ADS)

The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru8--Ru12- have simple cubic structures, Ru13--Ru16- form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru17-, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru18--Ru20-. Our calculations also predict simple cubic structures for the smaller clusters Ru4--Ru7-, which were not accessible to electron diffraction measurements.

Waldt, Eugen; Hehn, Anna-Sophia; Ahlrichs, Reinhart; Kappes, Manfred M.; Schooss, Detlef

2015-01-01

193

Probes for anionic cell surface detection  

DOEpatents

Embodiments of the present invention are generally directed to compositions comprising a class of molecular probes for detecting the presence of anionic cell surfaces. Embodiments include compositions that are enriched for these compositions and preparations, particularly preparations suitable for use as laboratory/clinical reagents and diagnostic indicators, either alone or as part of a kit. An embodiment of the invention provides for a highly selective agent useful in the discernment and identification of dead or dying cells, such as apoptotic cells, in a relatively calcium-free environment. An embodiment of the invention provides a selective agent for the identification of bacteria in a mixed population of bacterial cells and nonbacterial cells.

Smith, Bradley D.

2013-03-05

194

[Metabolic surgery].  

PubMed

The prevalence of obesity and diabetes mellitus type 2 is constantly rising worldwide and is one of the most threatening global health and health economic problems. Whereas bariatric surgery is well established in the treatment of morbid obesity, the surgical treatment options for type 2 diabetes mellitus alone are still under discussion (metabolic surgery). Bariatric procedures differ considering weight loss and influencing associated comorbidities. Detailed knowledge of available surgical treatment options for morbid obesity, the risks and requirements of laparoscopic skills, effectiveness and, as far as already known, mechanisms of action are crucial for appropriate implementation. PMID:22695815

Jurowich, C; Germer, C T; Seyfried, F; Thalheimer, A

2012-06-01

195

Novel Gapped Quantum Wire  

NASA Astrophysics Data System (ADS)

High quality state of the art quantum wires (QWRs) can be fabricated by the novel cleaved edge overgrowth technique, proposed by (Pfeiffer et al., 1990). Transverse quantization in these QWRs leads to a succession of nested energy bands. With the lowest two successive energy levels occupied, gapped phases are possible including, e.g, an intersubband charge density wave (ICDW) and a Cooper phase with strong superconducting fluctuations (Starykh et al., 2000). Due to the possibility of density reorganization, in which it becomes favorable for the two lowest subbands to match their densities, the ICDW is usually the most likely state. Recently, by exploiting the valley degeneracy in AlAs, a single QWR has been fabricated with two degenerate nonoverlapping bands separated in k space by half an Umklapp vector (Moser et al. 2004). For low densities this structure is able to access a multiple subband regime that is not subject to the density reorganizing ICDW, leaving the Cooper phase to flourish. Using Abelian bosonization, we explore the relevant interaction terms for this system, including Umklapp assisted Cooper scattering, and discuss the phase diagram.

Datta, Trinanjan

2005-03-01

196

Novel Gapped Quantum Wire  

NASA Astrophysics Data System (ADS)

High quality state of the art quantum wires (QWRs) can be fabricated by the novel Cleaved Edge Overgrowth (CEO) technique, proposed by (Pfeiffer et al, 1990). Transverse quantization in these QWRs leads to a succession of nested energy bands. With the lowest two successive energy levels occupied, gapped phases are possible including, e.g., an intersubband charge density wave (ICDW) and a Cooper phase with strong superconducting fluctuations (Starykh et al, 2000). Due to the possibility of density reorganization, in which it becomes favorable for the two lowest subbands to match their densities, the ICDW is usually the most likely state. Recently, by exploiting the valley degeneracy in AlAs, a single QWR has been fabricated with two degenerate nonoverlapping bands separated in k space by half an Umklapp vector (Moser et al 2004). For low densities the structure is able to access a multiple subband regime that is not subject to the density reorganizing ICDW, leaving a Cooper phase to flourish. Using Abelian bosonization, we explore the relevant interaction terms for this system, including Umklapp assisted Cooper scattering and discuss the phase diagram.

Datta, Trinanjan

2005-04-01

197

Research and Applications: Gap Analysis  

NSDL National Science Digital Library

The US Geological Survey's Gap Analysis Program (GAP) is a cooperative project that attempts to map land cover and vertebrate species distribution in order to enhance conservation land management activities. Visitors can view data about protected areas and species as well as read USGS publications on this program.

198

The chemistry of molecular anions in circumstellar sources  

NASA Astrophysics Data System (ADS)

The detection of negatively charged molecules in the interstellar and circumstellar medium in the past four years has been one of the most impacting surprises in the area of molecular astrophysics. It has motivated the interest of astronomers, physicists, and chemists on the study of the spectroscopy, chemical kinetics, and prevalence of molecular anions in the different astronomical regions. Up to six different molecular anions have been discovered in space to date, the last one being the small ion CN-, which has been observed in the envelope of the carbon star IRC +10216 and which contrary to the other larger anions is not formed by electron attachment to CN, but through reactions of large carbon anions with nitrogen atoms. Here we briefly review the current status of our knowledge of the chemistry of molecular anions in space, with particular emphasis on the circumstellar source IRC +10216, which to date is the astronomical source harboring the largest variety of anions.

Agúndez, Marcelino; Cernicharo, José; Guélin, Michel

2015-01-01

199

Process for removing sulfate anions from waste water  

DOEpatents

A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

Nilsen, David N. (Lebanon, OR); Galvan, Gloria J. (Albany, OR); Hundley, Gary L. (Corvallis, OR); Wright, John B. (Albany, OR)

1997-01-01

200

Gap ecology in Florida scrub: Species occurrence, diversity and gap properties  

Microsoft Academic Search

Questions: Studies of gap effects have been conducted mainly in forests. We studied gap ecology in a pyrogenic Ceratiola ericoides (Florida rosemary) dominated shrubland and asked: How do gap size and the frequency of large gaps change across the fire chronosequence? Do larger gaps differ from smaller gaps in vegetation structure or species diversity? Are effects of gaps independent of,

Eric S. Menges; Alaä Craddock; Jessica Salo; Robin Zinthefer; Carl W. Weekley

2008-01-01

201

Energy gaps in ?-graphdiyne nanoribbons  

SciTech Connect

?-graphdiyne is a novel predicted Dirac cone material, which is similar to graphene. But the absence of a band gap significantly limits its practical applications. In order to extend this limitation, an opening of energy gap is needed. To this end, we resort to the nanoribbon structure of ?-graphdiyne. This is a conventional proposal to open up the energy gaps in nanomaterials. The results show that both the armchair and the zigzag ?-graphdiyne nanoribbons do generate energy gaps, which are width-dependent. In addition, the underlying mechanism of this opening is explored. The former is ascribed to the combination of quantum confinement and edges' effect, while the latter arises from the edge magnetic ordering. These novel nanoribbons with opening energy gaps would be potentially used in electronic devices.

Niu, X. N.; Yang, D. Z.; Si, M. S., E-mail: sims@lzu.edu.cn; Xue, D. S., E-mail: xueds@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

2014-04-14

202

PROGRESS REPORT. SUPRAMOLECULAR CHEMISTRY OF SELECTIVE ANION RECOGNITION FOR ANIONS OF ENVIRONMENTAL RELEVANCE  

EPA Science Inventory

This project involves the design and synthesis of receptors for oxoanions of environmental importance and specifically those found in high level waste tanks. Polyammonium macrocycles as receptors and nitrate as anion were the focus of the first phase of this project. A second pha...

203

Charge regulation enables anionic hydroxypropyl guar-borate adsorption onto anionic and cationic polystyrene latex.  

PubMed

Reported are adsorption isotherms for guar and hydroxypropyl guar (HPG), with and without the presence of borate ions, onto surfactant free anionic polystyrene latex. Guar and HPG formed adsorbed monolayers on the hydrophobic latex. The presence of borate ions converted the nonionic guar and HPG into an anionic polyelectrolyte. However, there was no measurable influence of bound borate ions on the adsorption of guar or HPG onto anionic, hydrophobic latex. To underscore the unusual behavior of HPG-borate, a sample of HPG was oxidized to introduce carboxyl groups, and the adsorption of the carboxylated HPG onto anionic polystyrene was measured. Unlike HPG-borate, oxidized HPG did not adsorb onto negative polystyrene latex at neutral pH because of electrostatic repulsion. To explain the adsorption of negative HPG-borate onto negative latex, we proposed that as HPG-borate segments approach the latex surface, the negative electrostatic potential near the latex surface induces the detachment of the labile borate groups from HPG. PMID:21030034

Zhang, Liang; Pelton, Robert; Ketelson, Howard; Meadows, David

2011-01-15

204

GAP Analysis Bulletin Number 15  

USGS Publications Warehouse

The Mission of the Gap Analysis Program (GAP) is to promote conservation by providing broad geographic information on biological diversity to resource managers, planners, and policy makers who can use the information to make informed decisions. As part of the National Biological Information Infrastructure (NBII) ?a collaborative program to provide increased access to data and information on the nation?s biological resources--GAP data and analytical tools have been used in hundreds of applications: from basic research to comprehensive state wildlife plans; from educational projects in schools to ecoregional assessments of biodiversity. The challenge: keeping common species common means protecting them BEFORE they become threatened. To do this on a state or regional basis requires key information such as land cover descriptions, predicted distribution maps for native animals, and an assessment of the level of protection currently given to those plants and animals. GAP works cooperatively with Federal, state, and local natural resource professionals and academics to provide this kind of information. GAP activities focus on the creation of state and regional databases and maps that depict patterns of land management, land cover, and biodiversity. These data can be used to identify ?gaps? in conservation--instances where an animal or plant community is not adequately represented on the existing network of conservation lands. GAP is administered through the U.S. Geological Survey. Through building partnerships among disparate groups, GAP hopes to foster the kind of collaboration that is needed to address conservation issues on a broad scale. For more information, contact: John Mosesso National GAP Director 703-648-4079 Kevin Gergely National GAP Operations Manager 208-885-3565

Maxwell, Jill, (Edited By); Gergely, Kevin; Aycrigg, Jocelyn; Canonico, Gabrielle; Davidson, Anne; Coffey, Nicole

2008-01-01

205

An intracellular anion channel critical for pigmentation.  

PubMed

Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and pigmentation deficits, impaired retinal development, and increased susceptibility to skin and eye cancers. The most common form of albinism is caused by mutations in oculocutaneous albinism II (OCA2), a melanosome-specific transmembrane protein with unknown function. Here we used direct patch-clamp of skin and eye melanosomes to identify a novel chloride-selective anion conductance mediated by OCA2 and required for melanin production. Expression of OCA2 increases organelle pH, suggesting that the chloride channel might regulate melanin synthesis by modulating melanosome pH. Thus, a melanosomal anion channel that requires OCA2 is essential for skin and eye pigmentation. PMID:25513726

Bellono, Nicholas W; Escobar, Iliana E; Lefkovith, Ariel J; Marks, Michael S; Oancea, Elena

2014-01-01

206

Deuterium anions in inertial electrostatic confinement devices.  

PubMed

A magnetic deflection-energy analyzer and Faraday trap diagnostic have been used to make measurements of divergent deuterium anion flow in the inertial electrostatic confinement experiment at the University of Wisconsin-Madison (UW-IEC) [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, I. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)], a device to confine high-energy light ions in a spherically symmetric electrostatic potential well. Deuterium anion current densities as high as 8.5 microA/cm2 have been measured at the wall of the UW-IEC device, 40 cm from the surface of the device cathode with a detector assembly of admittance area 0.7 cm2. Energy spectra obtained using a magnetic deflection-energy analyzer diagnostic indicate the presence of D2(-), and D- ions produced through thermal electron attachment near the device cathode, as well as D- ions produced via charge-transfer processes between the anode and cathode of the device. PMID:19905231

Boris, D R; Alderson, E; Becerra, G; Donovan, D C; Egle, B; Emmert, G A; Garrison, L; Kulcinski, G L; Santarius, J F; Schuff, C; Zenobia, S J

2009-09-01

207

Anionic derivatives of uracil: fragmentation and reactivity.  

PubMed

Uracil is an essential biomolecule for terrestrial life, yet its prebiotic formation mechanisms have proven elusive for decades. Meteorites have been shown to contain uracil and the interstellar abundance of aromatic species and nitrogen-containing molecules is well established, providing support for uracil's presence in the interstellar medium (ISM). The ion chemistry of uracil may provide clues to its prebiotic synthesis and role in the origin of life. The fragmentation of biomolecules provides valuable insights into their formation. Previous research focused primarily on the fragmentation and reactivity of cations derived from uracil. In this study, we explore deprotonated uracil-5-carboxylic acid and its anionic fragments to elucidate novel reagents of uracil formation and to characterize the reactivity of uracil's anionic derivatives. The structures of these fragments are identified through theoretical calculations, further fragmentation, experimental acidity bracketing, and reactivity with several detected and potential interstellar species (SO2, OCS, CS2, NO, N2O, CO, NH3, O2, and C2H4). Fragmentation is achieved through collision induced dissociation (CID) in a commercial ion trap mass spectrometer, and all reaction rate constants are measured using a modification of this instrument. Experimental data are supported by theoretical calculations at the B3LYP/6-311++G(d,p) level of theory. Lastly, the astrochemical implications of the observed fragmentation and reaction processes are discussed. PMID:25036757

Cole, Callie A; Wang, Zhe-Chen; Snow, Theodore P; Bierbaum, Veronica M

2014-09-01

208

Aluminum Zintl anion moieties within sodium aluminum clusters  

SciTech Connect

Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup ?}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany)] [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States)] [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)

2014-02-07

209

Nonvalence correlation-bound anion states of spherical fullerenes.  

PubMed

We present a one-electron model Hamiltonian for characterizing nonvalence correlation-bound anion states of fullerene molecules. These states are the finite system analogs of image potential states of metallic surfaces. The model potential accounts for both atomic and charge-flow polarization and is used to characterize the nonvalence correlation-bound anion states of the C60, (C60)2, C240, and C60@C240 fullerene systems. Although C60 is found to have a single (s-type) nonvalence correlation-bound anion state, the larger fullerenes are demonstrated to have multiple nonvalence correlation-bound anion states. PMID:24978808

Voora, Vamsee K; Jordan, Kenneth D

2014-08-13

210

Recognition of Chiral Carboxylic Anions by Artificial Receptors  

PubMed Central

Many carboxylic molecules, ranging from drugs to flavors and fragrances, contain chiral centers. As a consequence, research has been carried out in order to design and synthesize artificial receptors for carboxylic anions. Many problems have to be solved for binding anions. The results obtained in the binding of carboxylic anions by guanidine, secondary ammonium and metal-center have been selected. The last part of this review focuses on chiral recognition of carboxylic anions by organic and metal-based chiral receptors. PMID:20957098

Dieng, Pape Sylla; Sirlin, Claude

2010-01-01

211

Purification Or Organic Acids Using Anion Exchange Chromatography.  

DOEpatents

Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams.

Ponnampalam; Elankovan (Okemos, MI)

2001-09-04

212

Mind the Gap  

NASA Astrophysics Data System (ADS)

Astronomers have been able to study planet-forming discs around young Sun-like stars in unsurpassed detail, clearly revealing the motion and distribution of the gas in the inner parts of the disc. This result, which possibly implies the presence of giant planets, was made possible by the combination of a very clever method enabled by ESO's Very Large Telescope. Uncovering the disc ESO PR Photo 27a/08 Planet-forming Disc Planets could be home to other forms of life, so the study of exoplanets ranks very high in contemporary astronomy. More than 300 planets are already known to orbit stars other than the Sun, and these new worlds show an amazing diversity in their characteristics. But astronomers don't just look at systems where planets have already formed - they can also get great insights by studying the discs around young stars where planets may currently be forming. "This is like going 4.6 billion years back in time to watch how the planets of our own Solar System formed," says Klaus Pontoppidan from Caltech, who led the research. Pontoppidan and colleagues have analysed three young analogues of our Sun that are each surrounded by a disc of gas and dust from which planets could form. These three discs are just a few million years old and were known to have gaps or holes in them, indicating regions where the dust has been cleared and the possible presence of young planets. The new results not only confirm that gas is present in the gaps in the dust, but also enable astronomers to measure how the gas is distributed in the disc and how the disc is oriented. In regions where the dust appears to have been cleared out, molecular gas is still highly abundant. This can either mean that the dust has clumped together to form planetary embryos, or that a planet has already formed and is in the process of clearing the gas in the disc. For one of the stars, SR 21, a likely explanation is the presence of a massive giant planet orbiting at less than 3.5 times the distance between the Earth and the Sun, while for the second star, HD 135344B, a possible planet could be orbiting at 10 to 20 times the Earth-Sun distance. The observations of the third star, TW Hydrae, may also require the presence of one or two planets. "Our observations with the CRIRES instrument on ESO's Very Large Telescope clearly reveal that the discs around these three young, Sun-like stars are all very different and will most likely result in very different planetary systems," concludes Pontoppidan. "Nature certainly does not like to repeat herself" [1]. "These kinds of observations complement the future work of the ALMA observatory, which will be imaging these discs in great detail and on a larger scale," adds Ewine van Dishoeck, from Leiden Observatory, who works with Pontoppidan. To study the gaps in dust discs that are the size of the Solar System around stars that are located up to 400 light-years away is a daunting challenge that requires a clever solution and the best possible instruments [2]. "Traditional imaging cannot hope to see details on the scale of planetary distances for objects located so far away," explains van Dishoeck. "Interferometry can do better but won't allow us to follow the motion of the gas." Astronomers used a technique known as 'spectro-astrometric imaging' to give them a window into the inner regions of the discs where Earth-like planets may be forming. They were able not only to measure distances as small as one-tenth the Earth-Sun distance, but to measure the velocity of the gas at the same time [3]. "The particular configuration of the instrument and the use of adaptive optics allows astronomers to carry out observations with this technique in a very user-friendly way: as a consequence, spectro-astrometric imaging with CRIRES can now be routinely performed," says team member Alain Smette, from ESO [4].

2008-09-01

213

Production of bulk chemicals via novel metabolic pathways in microorganisms.  

PubMed

Metabolic engineering has been playing important roles in developing high performance microorganisms capable of producing various chemicals and materials from renewable biomass in a sustainable manner. Synthetic and systems biology are also contributing significantly to the creation of novel pathways and the whole cell-wide optimization of metabolic performance, respectively. In order to expand the spectrum of chemicals that can be produced biotechnologically, it is necessary to broaden the metabolic capacities of microorganisms. Expanding the metabolic pathways for biosynthesizing the target chemicals requires not only the enumeration of a series of known enzymes, but also the identification of biochemical gaps whose corresponding enzymes might not actually exist in nature; this issue is the focus of this paper. First, pathway prediction tools, effectively combining reactions that lead to the production of a target chemical, are analyzed in terms of logics representing chemical information, and designing and ranking the proposed metabolic pathways. Then, several approaches for potentially filling in the gaps of the novel metabolic pathway are suggested along with relevant examples, including the use of promiscuous enzymes that flexibly utilize different substrates, design of novel enzymes for non-natural reactions, and exploration of hypothetical proteins. Finally, strain optimization by systems metabolic engineering in the context of novel metabolic pathways constructed is briefly described. It is hoped that this review paper will provide logical ways of efficiently utilizing 'big' biological data to design and develop novel metabolic pathways for the production of various bulk chemicals that are currently produced from fossil resources. PMID:23280013

Shin, Jae Ho; Kim, Hyun Uk; Kim, Dong In; Lee, Sang Yup

2013-11-01

214

Postsynaptic Deregulation in GAP-43 Heterozygous Mouse Barrel Cortex  

PubMed Central

Formation of whisker-related barrels in primary somatosensory cortex (S1) requires communication between presynaptic thalamocortical afferents (TCAs) and postsynaptic cortical neurons. GAP-43 is crucially involved in targeting TCAs to postsynaptic S1 neurons but its influence on the interactions between these 2 elements has not been explored. Here, we tested the hypothesis that reduced early expression of presynaptic GAP-43 (GAP-43 heterozygous [HZ] mice) alters postsynaptic differentiation of barrel cells. We found a transient increase in cytochrome oxidase staining between P6 and P14 in HZ animals, indicative of increased metabolic activity in barrel cortex during this time. Golgi impregnation and microtubule-associated protein 2 immunohistochemistry showed anomalous dendritic patterning in GAP-43 HZ cortex at P5, with altered dendritic length and branching and abnormal retention of dendrites that extend into developing septa. This deficiency was no longer apparent at P7, suggesting partial recovery of dendritic pruning processes. Finally, we showed early defects in synaptogenesis from P4 to P5 with increased colocalization of NR1 and GluR1 staining in HZ mice. By P7, this colocalization had normalized to wild type levels. Taken together, our findings suggest abnormal postsynaptic differentiation in GAP-43 HZ cortex during early barrel development, followed by adaptive compensation and partial phenotypic rescue. PMID:19915093

Kelly, Emily A.; Tremblay, Marie-Ève; McCasland, James S.

2010-01-01

215

Electronic materials with a wide band gap: recent developments  

PubMed Central

The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap E g = 0.66?eV) after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (E g = 1.12?eV). This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider E g were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and ?-Ga2O3, offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity. PMID:25295170

Klimm, Detlef

2014-01-01

216

Exploiting Metabolic Differences in Glioma Therapy  

PubMed Central

Brain function depends upon complex metabolic interactions amongst only a few different cell types, with as-trocytes providing critical support for neurons. Astrocyte functions include buffering the extracellular space, providing substrates to neurons, interchanging glutamate and glutamine for synaptic transmission with neurons, and facilitating access to blood vessels. Whereas neurons possess highly oxidative metabolism and easily succumb to ischemia, astrocytes rely more on glycolysis and metabolism associated with synthesis of critical intermediates, hence are less susceptible to lack of oxygen. Astrocytoma and higher grade glioma cells demonstrate both basic metabolic mechanisms of astrocytes as well as tumors in general, e.g. they show a high glycolytic rate, lactate extrusion, ability to proliferate even under hypoxia, and opportunistic use of mechanisms to enhance metabolism and blood vessel generation, and suppression of cell death pathways. There may be differences in metabolism between neurons, normal astrocytes and astrocytoma cells, providing therapeutic opportunities against astrocytomas, including a wide range of enzyme and transporter differences, regulation of hypoxia-inducible factor (HIF), glutamate uptake transporters and glutamine utilization, differential sensitivities of monocarboxylate transporters, presence of glycogen, high interlinking with gap junctions, use of NADPH for lipid synthesis, utilizing differential regulation of synthetic enzymes (e.g. isocitrate dehydrogenase, pyruvate carboxylase, pyruvate dehydrogenase, lactate dehydrogenase, malate-aspartate NADH shuttle) and different glucose uptake mechanisms. These unique metabolic susceptibilities may augment conventional therapeutic attacks based on cell division differences and surface receptors alone, and are starting to be implemented in clinical trials. PMID:22339075

Galeffi, Francesca; Turner, Dennis A.

2013-01-01

217

Exploiting metabolic differences in glioma therapy.  

PubMed

Brain function depends upon complex metabolic interactions amongst only a few different cell types, with astrocytes providing critical support for neurons. Astrocyte functions include buffering the extracellular space, providing substrates to neurons, interchanging glutamate and glutamine for synaptic transmission with neurons, and facilitating access to blood vessels. Whereas neurons possess highly oxidative metabolism and easily succumb to ischemia, astrocytes rely more on glycolysis and metabolism associated with synthesis of critical intermediates, hence are less susceptible to lack of oxygen. Astrocytoma and higher grade glioma cells demonstrate both basic metabolic mechanisms of astrocytes as well as tumors in general, e.g. they show a high glycolytic rate, lactate extrusion, ability to proliferate even under hypoxia, and opportunistic use of mechanisms to enhance metabolism and blood vessel generation, and suppression of cell death pathways. There may be differences in metabolism between neurons, normal astrocytes and astrocytoma cells, providing therapeutic opportunities against astrocytomas, including a wide range of enzyme and transporter differences, regulation of hypoxia-inducible factor (HIF), glutamate uptake transporters and glutamine utilization, differential sensitivities of monocarboxylate transporters, presence of glycogen, high interlinking with gap junctions, use of NADPH for lipid synthesis, utilizing differential regulation of synthetic enzymes (e.g. isocitrate dehydrogenase, pyruvate carboxylase, pyruvate dehydrogenase, lactate dehydrogenase, malate-aspartate NADH shuttle) and different glucose uptake mechanisms. These unique metabolic susceptibilities may augment conventional therapeutic attacks based on cell division differences and surface receptors alone, and are starting to be implemented in clinical trials. PMID:22339075

Galeffi, Francesca; Turner, Dennis A

2012-12-01

218

Electronic characterization of defects in narrow gap semiconductors  

NASA Technical Reports Server (NTRS)

We use a Green's function technique to calculate the position of deep defects in narrow gap semiconductors. We consider substitutional (including antisite), vacancy, and interstitial (self and foreign) deep defects. We also use perturbation theory to look at the effect of nonparabolic bands on shallow defect energies and find nonparabolicity can increase the binding by 10 percent or so. We consider mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS). For substitutional and interstitial defects we look at the situation with and without relaxation. For substitutional impurities in MCT, MZT, and MZS, we consider x (the concentration of Cd or Zn) in the range 0.1 less than x less than 0.3 and also consider appropriate x so E(sub g) = 0.1 eV for each of the three compounds. We consider several cation site s-like deep levels and anion site p-like levels. For E(sub g) = 0.1 eV, we also consider the effects of relaxation. Similar comments apply to the interstitial deep levels whereas no relaxation is considered for the ideal vacancy model. Relaxation effects can be greater for the interstitial than the substitutional cases. Specific results are given in figures and tables and comparison to experiment is made in a limited number of cases. We find, for example, that I, Se, S, Rn, and N are possible cation site, s-like deep levels in MCT and Zn and Mg are for anion site, p-like levels (both levels for substitutional cases). The corresponding cation and anion site levels for interstitial deep defects are (Au, Ag, Hg, Cd, Cu, Zn) and (N, Ar, O, F). For the substitutional cases we have some examples of relaxation moving the levels into the band gap, whereas for the interstitial case we have examples where relaxation moves it out of the band gap. Future work involves calculating the effects of charge state interaction and seeing the effect of relaxation on vacancy levels.

Patterson, James D.

1994-01-01

219

Synthetic ion transporters that work with anion-? interactions, halogen bonds, and anion-macrodipole interactions.  

PubMed

The transport of ions and molecules across lipid bilayer membranes connects cells and cellular compartments with their environment. This biological process is central to a host of functions including signal transduction in neurons and the olfactory and gustatory sensing systems, the translocation of biosynthetic intermediates and products, and the uptake of nutrients, drugs, and probes. Biological transport systems are highly regulated and selectively respond to a broad range of physical and chemical stimulation. A large percentage of today's drugs and many antimicrobial or antifungal agents take advantage of these systems. Other biological transport systems are highly toxic, such as the anthrax toxin or melittin from bee venom. For more than three decades, organic and supramolecular chemists have been interested in developing new transport systems. Over time, curiosity about the basic design has evolved toward developing of responsive systems with applications in materials sciences and medicine. Our early contributions to this field focused on the introduction of new structural motifs with emphasis on rigid-rod scaffolds, artificial ?-barrels, or ?-stacks. Using these scaffolds, we have constructed selective systems that respond to voltage, pH, ligands, inhibitors, or light (multifunctional photosystems). We have described sensing applications that cover the three primary principles of sensor development: immunosensors that use aptamers, biosensors (an "artificial" tongue), and differential sensors (an "artificial" nose). In this Account, we focus on our recent interest in applying synthetic transport systems as analytical tools to identify the functional relevance of less common noncovalent interactions, anion-? interactions, halogen bonds, and anion-macrodipole interactions. Anion-? interactions, the poorly explored counterpart of cation-? interactions, occur in aromatic systems with a positive quadrupole moment, such as TNT or hexafluorobenzene. To observe these elusive interactions in action, we synthesized naphthalenediimide transporters of increasing ?-acidity up to an unprecedented quadrupole moment of +39 Buckinghams and characterized these systems in comparison with tandem mass spectrometry and computational simulations. With ?-acidic calixarenes and calixpyrroles, we have validated our results on anion-? interactions and initiated our studies of halogen bonds. Halogen bonds originate from the ?-hole that appears on top of electron-deficient iodines, bromines, and chlorines. Halogen-bond donors are ideal for anion transport because they are as strong and at least as directional as hydrogen-bond donors, but also hydrophobic. The discovery of the smallest possible organic anion transporter, trifluoroiodomethane, illustrates the power of halogen-bond donors. This molecule contains a single carbon atom and is a gas with a boiling point of -22 °C. Anion-macrodipole interactions, finally, differ significantly from anion-? interactions and halogen bonds because they are important in nature and cannot be studied with small molecules. We have used anion-transporting peptide/urea nanotubes to examine these interactions in synthetic transport systems. To facilitate the understanding of the described results, we also include an in-depth discussion of the meaning of Hill coefficients. The use of synthetic transport systems to catch less common noncovalent interactions at work is important because it helps to expand the collection of interactions available to create functional systems. Progress in this direction furthers fundamental knowledge and invites many different applications. For illustration, we briefly discuss how this knowledge could apply to the development of new catalysts. PMID:23547885

Vargas Jentzsch, Andreas; Hennig, Andreas; Mareda, Jiri; Matile, Stefan

2013-12-17

220

Organic anion transporting polypeptide mediates organic anion/HCO3- exchange.  

PubMed

Organic anion transporting polypeptide (oatp) is an integral membrane protein cloned from rat liver that mediates Na+-independent transport of organic anions such as sulfobromophthalein and taurocholic acid. Previous studies in rat hepatocytes suggested that organic anion uptake is associated with base exchange. To better characterize the mechanism of oatp-mediated organic anion uptake, we examined transport of taurocholate in a HeLa cell line stably transfected with oatp under the regulation of a zinc-inducible promoter (Shi, X., Bai, S., Ford, A. C., Burk, R. D., Jacquemin, E., Hagenbuch, B., Meier, P. J., and Wolkoff, A. W. (1995) J. Biol. Chem. 270, 25591-25595). Whereas noninduced transfected cells showed virtually no uptake of [3H]taurocholate, taurocholate uptake by induced cells was Na+-independent and saturable (Km = 19.4 +/- 3.3 microM; Vmax = 62.2 +/- 1.4 pmol/min/mg protein; n = 3). To test whether organic anion transport is coupled to HCO3- extrusion, we compared the rates of taurocholate-dependent HCO3- efflux from alkali-loaded noninduced and induced cells. Monolayers grown on glass coverslips were loaded with the pH-sensitive dye 2', 7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; intracellular pH (pHi) was measured by excitation ratio fluorometry. Noninduced and induced cells were alkalinized to an equivalent pHi ( approximately 7.7) by transient exposure to a 50 mM HCO3-, Cl--free solution. In the absence of extracellular Cl- and taurocholate, isohydric reduction of superfusate HCO3- concentration from 50 to 25 mM resulted in an insignificant change in pHi over time (dpHi/dt) in both groups. Addition of 25 microM taurocholate to the superfusate led to a rapid fall in pHi in induced (-0.037 +/- 0.011 pH units/min to pHi of 7.41 +/- 0.14) but not in noninduced (0.003 +/- 0.006 pH units/min to pHi of 7.61 +/- 0.08) cells (p < 0.03). These data indicate that oatp-mediated taurocholate transport is Na+-independent, saturable, and accompanied by HCO3- exchange. We conclude that organic anion/base exchange is an important, potentially regulatable component of oatp function. PMID:9334206

Satlin, L M; Amin, V; Wolkoff, A W

1997-10-17

221

Living anionic polymerization using a microfluidic reactor.  

PubMed

Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 degrees C) and high monomer concentration (42%, by volume). The reactions were safely maintained at a controlled temperature at all points in the reactor. Conducting these reactions in a batch reactor results in uncontrolled heat generation with potentially dangerous rises in pressure. Moreover, the microfluidic nature of these devices allows for flexible 2D designing of the flow channel. Four flow designs were examined (straight, periodically pinched, obtuse zigzag, and acute zigzag channels). The ability to use the channel pattern to increase the level of mixing throughout the reactor was evaluated. When moderately high molecular mass polymers with increased viscosity were made, the patterned channels produced polymers with narrower PDI, indicating that passive mixing arising from the channel design is improving the reaction conditions. PMID:19107294

Iida, Kazunori; Chastek, Thomas Q; Beers, Kathryn L; Cavicchi, Kevin A; Chun, Jaehun; Fasolka, Michael J

2009-01-21

222

Poly(phenylene)-based anion exchange membrane  

DOEpatents

A poly(phenylene) compound of copolymers that can be prepared with either random or multiblock structures where a first polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 2 pendant phenyl groups and 4 pendant tolyl groups and the second polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 6 pendant phenyl groups. The second polymer has chemical groups attached to some of the pendant phenyl groups selected from CH.sub.3, CH.sub.2Br, and CH.sub.2N(CH.sub.3).sub.3Br groups. When at least one group is CH.sub.2N(CH.sub.3).sub.3Br, the material functions as an anion exchange membrane.

Hibbs, Michael (Albuquerque, NM); Cornelius, Christopher J. (Albuquerque, NM); Fujimoto, Cy H. (Albuquerque, NM)

2011-02-15

223

Plenary 1 – Gaps in Oncology  

Cancer.gov

The first plenary of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study Original Version provides background for the curriculum and identifies gaps in current and desired comprehensive cancer care.

224

Gap solitons in microstructured metamaterials  

Microsoft Academic Search

This paper shows that envelope gap solitons can be supported in lossless metamaterials exhibiting a cubic dielectric nonlinearity when the carrier frequency is tuned inside the stop band separating left-handed and right-handed propagative spectral regions.

S. Longhi

2005-01-01

225

Extended negative dietary cation-anion difference feeding does not negatively affect postpartum performance of multiparous dairy cows.  

PubMed

Low postpartum blood calcium remains one of the largest constraints to postpartum feed intake, milk yield, and energy balance in transitioning dairy cows. Supplemental dietary anions decrease the dietary cation-anion difference (DCAD) and reduce the risk for postpartum hypocalcemia. Prepartum management strategies aiming to minimize social stress and diet changes have resulted in a need to explore the effects of extended exposure to a negative DCAD (>21 d) diet. Holstein and Holstein-cross dairy cows (n=60) were assigned to 1 of 3 treatments 42 d before expected calving to evaluate effects of supplying anions for 21 or 42 d during the dry period on energy status, postpartum production, and Ca homeostasis. Treatments included (1) a control diet (CON; DCAD=12 mEq/100 g of DM), (2) a 21-d negative DCAD diet (21-ND; DCAD=12 and -16 mEq/100 g of DM), and (3) a 42-d negative DCAD diet (42-ND; DCAD=-16 mEq/100 g of DM). Cows fed CON were fed positive DCAD prepartum for 42 d. Cows fed 21-ND received the positive DCAD (12 mEq/100 g of DM) diet for the first 21 d of the dry period and the anionic diet (-16 mEq/100 g of DM) from d 22 until calving. Cows fed 42-ND received the anionic diet for the entire dry period. Control and anionic diets were formulated by using 2 isonitrogenous protein mixes: (1) 97.5% soybean meal and (2) 52.8% BioChlor (Church & Dwight Co. Inc.), 45.8% soybean meal. Supplementing anions induced a mild metabolic acidosis, reducing urine pH for 21-ND and 42-ND compared with CON. Prepartum DMI was not different among treatments. Postpartum DMI was higher for 21-ND compared with CON (20.8 vs. 18.1±1.1 kg/d), and 42-ND had similar DMI compared with 21-ND. During the first 56 d of lactation 21-ND had greater average milk production compared with CON (44.8 vs. 39.2±2.1 kg/d). Average milk production by 42-ND was similar to 21-ND. Postpartum total blood Ca concentration was greater for 42-ND. Cows fed anionic diets prepartum tended to have lower lipid accumulation in the liver after calving compared with CON. These data suggest low-DCAD diets fed for 21 or 42 d during the dry period can have positive effects on postpartum DMI, Ca homeostasis, and milk production. PMID:23831094

Weich, W; Block, E; Litherland, N B

2013-09-01

226

Anion binding by biotin[6]uril in water.  

PubMed

In this contribution we show that the newly discovered 6 + 6 biotin-formaldehyde macrocycle Biotin[6]uril binds a variety of anionic guest molecules in water. We discuss how and why the anions are bound based on data obtained using NMR spectroscopy, mass spectrometry, isothermal titration calorimetry (ITC), computational calculations and single crystal X-ray crystallography. PMID:25407665

Lisbjerg, Micke; Nielsen, Bjarne E; Milhøj, Birgitte O; Sauer, Stephan P A; Pittelkow, Michael

2015-01-14

227

Hydration of Oxo Anions A Combined Computational and Experimental Structure  

E-print Network

Hydration of Oxo Anions A Combined Computational and Experimental Structure and Dynamics Study of Chemistry and Biotechnology Uppsala Doctoral Thesis Swedish University of Agricultural Sciences Uppsala 2014/Repro, Uppsala 2014 #12;Hydration of Oxo Anions. -A Combined Computational and Experimental Structure

228

8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE PROCESS. THE ANION EXCHANGE PROCESS PURIFIED AND CONCENTRATED PLUTONIUM-BEARING NITRIC ACID SOLUTIONS TO MAKE THEM ACCEPTABLE AS FEED FOR CONVERSION TO METAL. (6/20/60) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO

229

Eight electrode optical readout gap  

DOEpatents

A protective device for a plurality of electrical circuits includes a plurality of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

Boettcher, G.E.; Crain, R.W.

1984-01-01

230

Pneumatic gap sensor and method  

SciTech Connect

This patent describes in a casting system which including an apparatus for monitoring the gap between a casting nozzle and a casting surface of a substrate during casting of molten material, wherein the molten material is provided through a channel of the casting nozzle for casting onto the casting surface of the substrate for solidification. It comprises: a pneumatic gap mounted at least partially within a cavity in the casting nozzle adjacent the channel and having a sensor face located within the gap between the nozzle and the casting surface of the substrate, means for supply gas under predetermined pressure to the inlet orifice; and means for measuring the pressure of the gas within the sensor chamber during casting procedures, whereby relative changes in the gap can be determined by corresponding changes in the measured pressure. This patent also describes a method for monitoring the gap between a casting nozzle and a casting surface of a substrate for continuous casting of molten material. It comprises: providing a casting nozzle with a channel for directing the flow of molten material, locating the nozzle and the casting surface is proximity with one another and having a predetermined gap there-between, and dressing the sensor face to correspond in conformation to the casting surface and to adjust the predetermined distance as desired; providing a molten material to the nozzle for casting onto and casting surface; supplying gas at a predetermined pressure to the inlet orifice of the sensor during casting procedures.

Bagdal, K.T.; King, E.L.; Follstaedt, D.W.

1992-03-03

231

Selectivity Control in Synergistic Liquid-Liquid Anion Exchange of Univalent Anions via Structure-Specific Cooperativity between Quaternary Ammonium Cations and Anion Receptors  

SciTech Connect

Two anion receptors enhance liquid-liquid anion exchange when added to quaternary alkylammonium chloride anion exchangers, but with a striking dependence upon the structure of the alkylammonium cation. Two anion receptors were investigated, meso-octamethylcalix[4]pyrrole (C4P) and the bisthiourea tweezer 1,1'-(propane-1,3-diyl)bis(3-(4-sec-butylphenyl)thiourea (BTU). C4P has the unique ability in its cone anion-binding conformation to accept an appropriately sized electropositive species in the resulting cup formed by its four electron-rich pyrrole groups, while BTU is not expected to be predisposed for a specific host-guest interaction with the quaternary ammonium cations. It was therefore hypothesized that synergism between C4P and methyltri(C8,10)alkylammonium chloride (Aliquat 336) would be uniquely pronounced owing to insertion of the methyl group of the Aliquat cation into the C4P cup, and we present herein data supporting this expectation. While synergism is comparatively weak for both exchangers with the BTU receptor, synergism between C4P and Aliquat 336 is indeed so strong that anion exchange prefers chloride over more extractable nitrate and trifluoroacetate, effectively overcoming the ubiquitous Hofmeister bias. A thermochemical analysis of synergistic anion exchange has been provided for the first time, unraveling the observed selectivity behavior and resulting in the estimation of binding constants for C4P with the ion pairs of A336+ with Cl , Br , OAcF3 , NO3 , and I . The uniquely strong positive cooperativity between A336 and C4P underscores the advantage of a supramolecular approach in the design of synergistic anion exchange systems.

Borman, Christopher J [ORNL; Bonnesen, Peter V [ORNL; Moyer, Bruce A [ORNL

2012-01-01

232

Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance  

SciTech Connect

The major thrust of this project led by the University of Kansas (Prof. Kristin Bowman-Jones) entails the exploration of the principles of recognition and separation of sulfate by the design, synthesis, and testing of novel sulfate extractants. A key science need for the cleanup of tank wastes at Hanford has been identified in developing methods to separate those bulk waste components that have low solubilities in borosilicate glass. Sulfate has been identified as a particularly difficult and expensive problem in that its concentration in the waste is relatively high, its solubility in glass is especially low, and it interferes with the performance of both vitrification equipment and the glass waste form. The new extractants will be synthesized by the University of Kansas and the University of Texas, Austin. Oak Ridge National Laboratory (ORNL) is subjecting the new extractants to experiments that will determine their properties and effectiveness in separating sulfate from the major competing anions in the waste, especially nitrate. Such experiments will entail primarily liquid-liquid extraction. Current efforts focus on exciting new systems in which the anion receptors act as synergists for anion exchange.

Moyer, Bruce a.; Bostick, Debra A.; Fowler, Christopher J.; Kang, Hyun-Ah; Ruas, Alexandre; Delmau, Laetitia H.; Haverlock, Tamara J.; Llinares, Jose M.; Hossain, Alamgir; Kang, S. O.; Bowman-James, Kristin; Shriver, James A.; Marquez, Manuel; Sessler, Jonathan L.

2005-09-22

233

Metabolic arthropathies.  

PubMed

In this article, recent advances in the understanding of some of the metabolic arthropathies are reviewed. Among hemoglobinopathies, sickle-cell disease is frequently the source of rheumatic syndromes, as emphasized in recent epidemiologic studies. Avascular necrosis is one of the most common features and may be disabling, leading to total joint replacement of the hip or knee. Joint effusions more rarely are observed and have been associated with subchondral bone infarctions. The clinical and radiologic presentations of the arthropathy of hemochromatosis have been extensively reviewed. Screening for the disease appears important, because it is the only way to prevent progressive worsening of organ involvement and arthropathy in particular. The rheumatic involvement in type IIa and type III hyperlipoproteinemias recently was confirmed in a case-control study. Magnetic resonance imaging appears to be useful in assessing the extent and activity of bone marrow involvement in Gaucher's disease. Replacement therapy is developing. Dialysis-associated amyloidosis remains the target of active research, which recently led to the identification of several newly recognized components, including alpha 2-macroglobulin and hyaluronan. The main component of this amyloid, beta 2-microglobulin, has been shown to be modified by advanced glycosylation products, and these changes appear to confer inflammatory properties on the molecule. PMID:8068518

Timsit, M A; Bardin, T

1994-07-01

234

p53 and metabolism  

Microsoft Academic Search

Although metabolic alterations have been observed in cancer for almost a century, only recently have the mechanisms underlying these changes been identified and the importance of metabolic transformation realized. p53 has been shown to respond to metabolic changes and to influence metabolic pathways through several mechanisms. The contributions of these activities to tumour suppression are complex and potentially rather surprising:

Karen H. Vousden; Kevin M. Ryan

2009-01-01

235

Explaining the gender wealth gap.  

PubMed

To assess and explain the United States' gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family's best financial reporters. We find large gender wealth gaps between currently married men and women, and between never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. After controlling for the full model, we find that a gender wealth gap remains between married men and women that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

Ruel, Erin; Hauser, Robert M

2013-08-01

236

Explaining the Gender Wealth Gap  

PubMed Central

To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

Ruel, Erin; Hauser, Robert M.

2013-01-01

237

Origins of Electronic Band Gap Reduction in Cr /N Codoped TiO2  

NASA Astrophysics Data System (ADS)

Recent studies indicated that noncompensated cation-anion codoping of wide-band-gap oxide semiconductors such as anatase TiO2 significantly reduces the optical band gap and thus strongly enhances the absorption of visible light [W. Zhu et al., Phys. Rev. Lett. 103, 226401 (2009), 10.1103/PhysRevLett.103.226401]. We used soft x-ray spectroscopy to fully determine the location and nature of the impurity levels responsible for the extraordinarily large (˜1 eV) band gap reduction of noncompensated codoped rutile TiO2. It is shown that Cr /N codoping strongly enhances the substitutional N content, compared to single element doping. The band gap reduction is due to the formation of Cr 3d3 levels in the lower half of the gap while the conduction band minimum is comprised of localized Cr 3d and delocalized N 2p states. Band gap reduction and carrier delocalization are critical elements for efficient light-to-current conversion in oxide semiconductors. These findings thus raise the prospect of using codoped oxide semiconductors with specifically engineered electronic properties in a variety of photovoltaic and photocatalytic applications.

Parks Cheney, C.; Vilmercati, P.; Martin, E. W.; Chiodi, M.; Gavioli, L.; Regmi, M.; Eres, G.; Callcott, T. A.; Weitering, H. H.; Mannella, N.

2014-01-01

238

Lyotropic anions. Na channel gating and Ca electrode response  

PubMed Central

The effects of external anions on gating of Na channels of frog skeletal muscle were studied under voltage clamp. Anions reversibly shift the voltage dependence of peak sodium permeability and of steady state sodium inactivation towards more negative potentials in the sequence: methanesulfonate less than or equal to Cl- less than or equal to acetate less than Br- less than or equal to NO-3 less than or equal to SO2-4 less than benzenesulfonate less than SCN- less than ClO-4; approximately the lyotropic sequence. Voltage shifts are graded with mole fraction in mixtures and are roughly additive to calcium shifts. The peak PNa is not greatly affected. Except for SO2-4, these anions did not change the Ca++ activity of the solutions as measured with the dye murexide. Shifts of gating can be explained as the electrostatic effect of anion adsorption to the Na channel or to nearby lipid. Such adsorption is expected to follow the lyotropic series. Anions also interfere significantly with the response of a Ca-sensitive membrane electrode following the same sequence of effectiveness as the shifts of gating. The lyotropic anions decrease the Ca++ sensitivity and cause anomalously negative responses of the Ca electrode because these anions are somewhat permeant in the hydrophobic detector membrane. PMID:6302198

1983-01-01

239

Microsolvation of small anions by aromatic molecules: An exploratory study  

NASA Astrophysics Data System (ADS)

This work was motivated by the experimental finding that the O2-/benzene interaction energy is unexpectedly large. To further explore the interactions of small anions with aromatic molecules, anion photoelectron spectroscopy was utilized to measure interaction strengths of the seed anions, O2- and NO-, complexed with several aromatic molecules, including benzene, naphthalene, pyridine, and pyrimidine. As in the case of O2-(benzene), the anion(aromatic)1 binding energies for the other complexes studied were also higher than one might have anticipated. In addition, the interaction energy of O2- complexed with a given aromatic molecule was, in every case studied, higher (by a factor of ˜1.5) than that of NO- complexed with the same aromatic. While the dependence of interaction strengths on solvent dipole moments and/or polarizabilities implied a substantial electrostatic component to the binding in these complexes, differences in the binding of O2- and NO- with these aromatic molecules showed that there is a distinct covalent aspect to the interaction as well. A significant portion of this interaction was attributed to the fact that O2- and NO- are both open-shell anions that are interacting with closed-shell aromatic molecules. In the accompanying paper [J. Chem. Phys. 116, 9672 (2002)] calculations on O2-(benzene)1 by Jalbout and Adamowicz shed additional light on the nature of small anion-aromatic molecule interactions. Last, results are also presented comparing the interaction energies of several multisolvent, anion-molecule complexes.

Le Barbu, K.; Schiedt, J.; Weinkauf, R.; Schlag, E. W.; Nilles, J. M.; Xu, S.-J.; Thomas, O. C.; Bowen, K. H.

2002-06-01

240

Mechanisms of anion conduction by coupled glutamate transporters.  

PubMed

Excitatory amino acid transporters (EAATs) are essential for terminating glutamatergic synaptic transmission. They are not only coupled glutamate/Na(+)/H(+)/K(+) transporters but also function as anion-selective channels. EAAT anion channels regulate neuronal excitability, and gain-of-function mutations in these proteins result in ataxia and epilepsy. We have combined molecular dynamics simulations with fluorescence spectroscopy of the prokaryotic homolog GltPh and patch-clamp recordings of mammalian EAATs to determine how these transporters conduct anions. Whereas outward- and inward-facing GltPh conformations are nonconductive, lateral movement of the glutamate transport domain from intermediate transporter conformations results in formation of an anion-selective conduction pathway. Fluorescence quenching of inserted tryptophan residues indicated the entry of anions into this pathway, and mutations of homologous pore-forming residues had analogous effects on GltPh simulations and EAAT2/EAAT4 measurements of single-channel currents and anion/cation selectivities. These findings provide a mechanistic framework of how neurotransmitter transporters can operate as anion-selective and ligand-gated ion channels. PMID:25635461

Machtens, Jan-Philipp; Kortzak, Daniel; Lansche, Christine; Leinenweber, Ariane; Kilian, Petra; Begemann, Birgit; Zachariae, Ulrich; Ewers, David; de Groot, Bert L; Briones, Rodolfo; Fahlke, Christoph

2015-01-29

241

Assessing the impact of anion-? effects on phenylalanine ion structures using IRMPD spectroscopy.  

PubMed

The gas-phase structures of two halide-bound phenylalanine anions (PheX(-), X = Cl(-) or Br(-)) and five fluorinated derivatives have been identified using infrared multiple photon dissociation (IRMPD) spectroscopy. The addition of electron-withdrawing groups to the aromatic ring creates a ?-acidic system that additionally stabilizes the halide above the ring face. Detailed ion structures were determined by comparing the IRMPD spectra with harmonic and anharmonic infrared spectra computed using B3LYP/6-311++G(d,p) as well as with 298 K enthalpies and Gibbs energies determined by the MP2(full)/6-311++G(2d,2p)//B3LYP/6-311++G(d,p) and MP2(full)/aug-cc-pVTZ//B3LYP/6-311++G(d,p) methods. PheX(-) structures were found to be dependent on both the nature of the anion and the extent of ring fluorination. Canonical isomers were established to be the dominant structures in every case, but halide addition significantly narrowed the energy gap with zwitterionic potential energy surfaces. This enabled zwitterions to appear as minor contributors to the gas-phase populations of Phe35F2Cl(-) and PheF5Br(-). PMID:25294414

Burt, Michael; Wilson, Kathleen; Marta, Rick; Hasan, Moaraj; Scott Hopkins, W; McMahon, Terry

2014-11-28

242

Anion and amine uptake and uncoupling in submitochondrial particles.  

PubMed

1. Unlike chloroplasts, submitochondrial particles are not uncoupled by nigericin + KCl or NH4Cl. Also the uncoupling effect of lipophilic anions is largely independent of the addition of weak bases. 2. Low concentrations of permeant anions cause a shift of the steady-state energy level rather than a cycle of energy utilization. The degree of inhibition of ATP synthesis by tetraphenylboron is larger than required for the uptake of the anion. 3. Lipophilic anions such as bromthymolblue, bromcresolpurple, and 8-anilino-1-napthalene sulphonate cause a pH-independent, 50% uncoupling in submitochondrial particles at concentrations of 3, 30 and 30 muM, respectively. The passive interaction of bromthymolblue and bromcresolpurple appears as a pH-dependent distribution between two pHases. ATP causes a pH-independent slight shift in the anion distribution, with negligible anion accumulation. 4. Addition of amines to energized submitochondrial particles results in two types of effects; uptake of amines and uncoupling. While in chloroplasts amine uptake and uncoupling are closely associated, this is not the case in submitochondrial particles. The uncoupling effect is observed only with lipophilic and not with hydrophilic amines, and the degree of uncoupling increases with the lipophilicity of the amines. The amine uptake, on the other hand, is accompanied by negligible uncoupling. 5. While the uptake of amines is dependent on the presence of non-permeant anions, such as Cl-, the uncoupling effect is independent of Cl-. Furthermore the amine uncoupling is markedly enhanced by lipophilic anions. 6. The view is discussed that the uncoupling effect of lipophilic anions and lipophilic amines in submitochondrial particles is due to a catalytic energy dissipation rather than to a stoichiometry energy utilization. The molecular mechanism of uncoupling presumably involves a cycling of charges after a perturbation of the membrane structure. PMID:2477

Azzone, G F; Gutweniger, H; Viola, E; Strinna, E; Massari, S; Colonna, R

1976-02-01

243

ABORT GAP CLEANING IN RHIC.  

SciTech Connect

During the RHIC Au-run in 2001 the 200 MHz storage cavity system was used for the first time. The rebucketing procedure caused significant beam debunching in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam could account for approximately 30%-40% of the total beam intensity. Some of it will be in the abort gap. In order to minimize the risk of magnet quenching due to uncontrolled beam losses at the time of a beam dump, a combination of a fast transverse kicker and copper collimators were used to clean the abort gap. This report gives an overview of the gap cleaning procedure and the achieved performance.

DREES,A.; AHRENS,L.; III FLILLER,R.; GASSNER,D.; MCINTYRE,G.T.; MICHNOFF,R.; TRBOJEVIC,D.

2002-06-03

244

Brain responses to filled gaps.  

PubMed

An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine the time course and spatial distribution of brain responses to ungrammatically filled gaps. The results indicate that the earliest brain response to the violation is an early left anterior negativity (eLAN). This ERP indexes an early phase of pure syntactic structure building, temporally preceding ERPs that reflect semantic integration and argument structure satisfaction. The finding is interpreted as evidence that gap-filling is mediated by structurally predicted empty categories, rather than directly by argument structure operations. PMID:16970985

Hestvik, Arild; Maxfield, Nathan; Schwartz, Richard G; Shafer, Valerie

2007-03-01

245

Genome-scale models of bacterial metabolism: reconstruction and applications  

PubMed Central

Genome-scale metabolic models bridge the gap between genome-derived biochemical information and metabolic phenotypes in a principled manner, providing a solid interpretative framework for experimental data related to metabolic states, and enabling simple in silico experiments with whole-cell metabolism. Models have been reconstructed for almost 20 bacterial species, so far mainly through expert curation efforts integrating information from the literature with genome annotation. A wide variety of computational methods exploiting metabolic models have been developed and applied to bacteria, yielding valuable insights into bacterial metabolism and evolution, and providing a sound basis for computer-assisted design in metabolic engineering. Recent advances in computational systems biology and high-throughput experimental technologies pave the way for the systematic reconstruction of metabolic models from genomes of new species, and a corresponding expansion of the scope of their applications. In this review, we provide an introduction to the key ideas of metabolic modeling, survey the methods, and resources that enable model reconstruction and refinement, and chart applications to the investigation of global properties of metabolic systems, the interpretation of experimental results, and the re-engineering of their biochemical capabilities. PMID:19067749

Durot, Maxime; Bourguignon, Pierre-Yves; Schachter, Vincent

2009-01-01

246

Suspension gaps identification based on cluster analysis  

Microsoft Academic Search

Too large suspension gaps will affect the service performance of the vehicle seriously. Therefore it is necessary to identify the suspension gap accurately. The traditional suspension gaps identification technology works in harsh environment and the detecting process not only can not achieve automation but also with lower identification precision. The flexible four-link mechanical model of wheel assembly and suspension gap

Yumei Liu; Xuehai Li; Su Jian; Xiaolai Jiang; Xiaoning Cao

2009-01-01

247

Theoretical study of the superoxide anion assisted firefly oxyluciferin formation  

NASA Astrophysics Data System (ADS)

This a theoretical Letter based on density functional theory, on the role of superoxide anion in firefly chemiluminescence in DMSO. We have found that this anion can attack luciferin radical molecules, thus forming a luciferin-like trianion. This latter molecule transfers an oxygen atom, which results in the formation of oxyluciferyl radical dianion and carbon dioxide molecules. Oxyluciferin is finally formed after an electron transfer from oxyluciferyl radical dianion to tert-BuOrad radical molecules. Thus, we have found evidence that firefly oxyluciferin can be formed in a energetically favorable superoxide anion-assisted reaction, without the need for the formation of firefly dioxetanone.

Pinto da Silva, Luís; Esteves da Silva, Joaquim C. G.

2013-12-01

248

Anionic peroxidase production by Arnebia euchroma callus.  

PubMed

Arnebia euchroma callus, obtained from the root cell culture of an Iranian native specimen, has gained a doubling time of 63 H after regular subculturing on Linsmaier-Skoog (LS) medium containing sugar (50 g/L), 2,4-dichlorophenoxyacetic acid (10(-6) M), and kinetin (10(-5) M) under darkness at 25°C. Despite the observed somaclonal variations, peroxidase production by the A. euchroma calli has been stable over 4 years under the aforementioned conditions. Isoelectric focusing experiments revealed that the partially purified A. euchroma peroxidases (AePoxs) are mainly anionic with pI values of about 5.5 and 6.6. AePox reaches its optimal activity at 55°C and pH 7.5. Results of the various kinetic studies suggest that AePox belongs to the type III plant peroxidases with no activity for the oxidation of 3-indoleacetic acid, but seems to play a role in the lignin biosynthesis and H(2) O(2) regulation during the proliferation of the A. euchroma cells on LS medium. Comparing the biochemical properties of AePox with horseradish peroxidase and in view of the ease of solid cell culture, the A. euchroma callus could be considered as a source of plant peroxidase for some biotechnological applications. PMID:22172108

Farhadi, Sahar; Haghbeen, Kamahldin; Marefatjo, Mohammad-Javad; Hoor, Marjan Ghiyami; Zahiri, Hossein Shahbani; Rahimi, Karim

2011-01-01

249

Ionic Block Copolymers for Anion Exchange Membranes  

NASA Astrophysics Data System (ADS)

Anion exchange membrane (AEM) fuel cells have regained interest because it allows the use of non-noble metal catalysts. Until now, most of the studies on AEM were based on random polyelectrolytes. In this work, Poly(vinylbenzyltrimethylammonium bromide)-b- (methylbutylene) ([PVBTMA][Br]-b-PMB) was studied by SAXS, TEM and dielectric spectroscopy to understand the fundamental structure-conductivity relationship of ion transport mechanisms within well-ordered block copolymers. The ionic conductivity and the formation of order structure were dependent on the casting solvent. Higher ion exchange capacity (IEC) of the membranes showed higher conductivity at as IEC values below 1.8mmol/g, as above this, the ionic conductivity decreases due to more water uptake leading to dilution of charge density. The humidity dependence of morphology exhibited the shifting of d-spacing to higher value and the alteration in higher characteristic peak of SAXS plot as the humidity increase from the dry to wet state. This phenomenon can be further explained by a newly developed polymer brush theory. Three ionic conduction pathways with different conduction mechanism within the membranes can be confirmed by broadband electric spectroscopy.

Tsai, Tsung-Han; Herbst, Dan; Giffin, Guinevere A.; di Noto, Vito; Witten, Tom; Coughlin, E. Bryan

2013-03-01

250

Distortions of ?-coordinated arenes with anionic character.  

PubMed

A qualitative analysis of the distortions that operate on the ? system of bridging arenes with anionic character is presented and substantiated by computational studies at the density functional B3LYP and CASSCF levels. The observed effects of bonding to two metal atoms and of the negative charge are an expansion of the arene ring due to the partial occupation of ?* orbitals, an elongation or compression distortion accompanied by a loss of the equivalence of carbon-carbon bonds due to a Jahn-Teller distortion of the arene dianions, and a ring puckering due to a second-order Jahn-Teller distortion that may appear independently of the existence of the first-order effect. The workings of the orbital mixing produced by these distortions have been revealed in a straightforward way by a pseudosymmetry analysis of the HOMOs of the distorted conformations. The systems studied include Li(I) and Y(III) adducts of benzene, as well as trimethylsilyl-substituted derivatives in the former case. An analysis of the structural data of a variety of purported di- and tetraanionic arene ligands coordinated to transition metals in several bridging modes has reproduced the main geometrical trends found in the computational study for the benzene and trimethylsilyl-substituted benzene dianions, allowing a classification of the variety of structural motifs found in the literature. PMID:25236369

Falceto, Andrés; Casanova, David; Alemany, Pere; Alvarez, Santiago

2014-11-01

251

Transport activity of chimaeric AE2-AE3 chloride/bicarbonate anion exchange proteins.  

PubMed

Chloride/bicarbonate anion exchangers (AEs), found in the plasma membrane of most mammalian cells, are involved in pH regulation and bicarbonate metabolism. Although AE2 and AE3 are highly similar in sequence, AE2-transport activity was 10-fold higher than AE3 (41 versus 4 mM x min(-1) respectively), when expressed by transient transfection of HEK-293 cells. AE2-AE3 chimaeras were constructed to define the region responsible for differences in transport activity. The level of AE2 expression was approx. 30% higher than that of AE3. Processing to the cell surface, studied by chemical labelling and confocal microscopy, showed that AE2 is processed to the cell surface approx. 8-fold more efficiently than AE3. The efficiency of cell-surface processing was dependent on the cytoplasmic domain, since the AE2 domain conferred efficient processing upon the AE3 membrane domain, with a predominant role for amino acids 322-677 of AE2. AE2 that was expressed in HEK-293 cells was glycosylated, but little of AE3 was. However, AE2 expressed in the presence of the glycosylation inhibitor, tunicamycin, was not glycosylated, yet retained 85 +/- 8% of anion-transport activity. Therefore glycosylation has little, if any, role in the cell-surface processing or activity of AE2 or AE3. We conclude that the low anion-transport activity of AE3 in HEK-293 cells is due to low level processing to the plasma membrane, possibly owing to protein interactions with the AE3 cytoplasmic domain. PMID:12578559

Fujinaga, Jocelyne; Loiselle, Frederick B; Casey, Joseph R

2003-05-01

252

Folk Belief Theory, the Rigor Gap, and the Achievement Gap  

ERIC Educational Resources Information Center

Folk belief theory is suggested as a primary cause for the persistence of the achievement gap. In this research-supported theory, culturally specified folk beliefs about learning and teaching prompt educators to direct more rigorous curriculum to high-advantage students but not to low-advantage students, resulting in impoverished pedagogy in…

Torff, Bruce

2014-01-01

253

Stacked insulator induction accelerator gaps  

SciTech Connect

Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

1997-05-01

254

In vivo tissue-wide synchronization of mitochondrial metabolic oscillations  

PubMed Central

Summary Little is known about the spatio-temporal coordination of mitochondrial metabolism in multicellular organisms in situ. Using intravital microscopy in live animals, we here report that mitochondrial metabolism undergoes rapid and periodic oscillations under basal conditions. Notably, mitochondria in vivo behave as a network of functionally coupled oscillators, which maintain a high level of coordination throughout the tissue via the activity of gap junctions. These findings reveal a unique aspect of the relationship between tissue architecture and self-organization of mitochondrial metabolism in vivo. PMID:25373899

Porat-Shliom, Natalie; Chen, Yun; Tora, Muhibullah; Shitara, Akiko; Masedunskas, Andrius; Weigert, Roberto

2014-01-01

255

Band gap engineering in BiNbO{sub 4} for visible-light photocatalysis  

SciTech Connect

We have investigated the electronic structure of anionic mono- (S, N, and C) and co-doping (N-N, C-N, S-C, and S-N) on BiNbO{sub 4} for the visible-light photocatalysis. The maximum band gap reduction of pure BiNbO{sub 4} is possible with the (C-S) co-doping and minimum with N mono-doping. The calculated binding energies show that the co-doped systems are more stable than their mono-doped counterparts. Our optical absorption curves indicate that the mono- (C) and co-anionic doped (N-N and C-S) BiNbO{sub 4} systems are promising materials for visible light photocatalysis.

Wang, B. C. [Department of Materials Science and Engineering, Royal Institute of Technology (KTH), S-100 44 Stockholm (Sweden); Nisar, J.; Pathak, B. [Department of Physics and Astronomy, Box 530, Uppsala University, S-751 21 Uppsala (Sweden); Kang, T. W. [QSRC, Department of Physics, Dongguk University, Seoul 100-715 (Korea, Republic of); Ahuja, R. [Department of Materials Science and Engineering, Royal Institute of Technology (KTH), S-100 44 Stockholm (Sweden); Department of Physics and Astronomy, Box 530, Uppsala University, S-751 21 Uppsala (Sweden)

2012-04-30

256

STRUCTURAL REQUIREMENTS OF ORGANIC ANION TRANSPORTING POLYPEPTIDE MEDIATED TRANSPORT  

E-print Network

The organic anion transporting polypeptides (human: OATP; other: Oatp) form a mammalian transporter superfamily that mediates the transport of structurally unrelated compounds across the cell membrane. Members in this superfamily participate...

Weaver, Yi Miao

2010-04-12

257

Synthesis and Characterization of Polyamine Bicycles for Anion Binding  

E-print Network

them from undesirable interactions. Only after detosylation to retrieve the secondary amines are the anion binding properties investigated. Through our research, we have discovered that when protected (tosylated), the m-xylyl azacryptand [1...

Morehouse, Paula Kay

2007-10-09

258

Nitrate Anion Exchange in Pu-238 Aqueous Scrap Recovery Operations  

SciTech Connect

Strong base, nitrate anion exchange (IX) is crucial to the purification of {sup 238}Pu solution feedstocks with gross levels of impurities. This paper discusses the work involved in bench scale experiments to optimize the nitrate anion exchange process. In particular, results are presented of experiments conducted to (a) demonstrate that high levels of impurities can be separated from {sup 238}Pu solutions via nitrate anion exchange and, (b) work out chemical pretreatment methodology to adjust and maintain {sup 238}Pu in the IV oxidation state to optimize the Pu(IV)-hexanitrato anionic complex sorption to Reillex-HPQ resin. Additional experiments performed to determine the best chemical treatment methodology to enhance recovery of sorbed Pu from the resin, and VIS-NIR absorption studies to determine the steady state equilibrium of Pu(IV), Pu(III), and Pu(VI) in nitric acid are discussed.

Pansoy-Hjelvik, M.E.; Silver, G.L.; Reimus, M.A.H.; Ramsey, K.B.

1999-01-31

259

DETERMINATION OF TRACE ANIONS IN WATER BY MULTIDIMENSIONAL ION CHROMATOGRAPHY  

EPA Science Inventory

Selenate, selenite, and arsenate ions were separated from the major anions chloride, nitrate, and sulfate in drinking water, surface water, and groundwater sources by collecting a selected portion of the ion chromatogram, after suppression, on a concentrator column and reinjectin...

260

Spectroscopic Characterization of the Isolated SF6 -Anions: Observation of  

E-print Network

of the significant internal excitation of a relatively complex molecular framework. Both these perfluorinated anions, in part, controlled by electron attachment.1 These two perfluorinated molecules are of fundamental

Lineberger, W. Carl

261

Temporary Anion States of Polyatomic Hydrocarbons KENNETH D. JORDAN'  

E-print Network

Temporary Anion States of Polyatomic Hydrocarbons KENNETH D. JORDAN' OSpemnenr Of C%sITIkby. M k I. A biographyand photograph of Kenneth D. Jordan appear In previous paper in this issue. far outweighsthat

Simons, Jack

262

Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF ? mediators  

SciTech Connect

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 ?M). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO{sub 3} 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO{sub 3}. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O{sub 2}{sup ?}). At high doses it provokes the secretion of TNF? and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O{sub 2}{sup ?} may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O{sub 2}{sup ?} may be blocked, prevailing damage to DNA by the TNF? route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium?related diseases. -- Highlights: ? Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ? At low doses uranyl nitrate induces generation of superoxide anion. ? At high doses uranyl nitrate provokes secretion of TNF?. ? Uranyl nitrate induces apoptosis through all the range of doses tested.

Orona, N.S. [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina)] [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142 (1122), Buenos Aires (Argentina)

2012-06-15

263

GAP JUNCTION FUNCTION AND CANCER  

EPA Science Inventory

Gap Junctions (GJs) provide cell-to-cell communication (GJIC) of essential metabolites and ions. Js allow tissues to average responses, clear waste products, and minimize the effects of xenobiotics by dilution and allowing steady-state catabolism. any chemicals can adversely affe...

264

Large gap magnetic suspension system  

NASA Technical Reports Server (NTRS)

The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

Abdelsalam, Moustafa K.; Eyssa, Y. M.

1991-01-01

265

GAP: Generic Aspects for PHP  

Microsoft Academic Search

In this paper, we explore how aspect-oriented programming can be implemented for the PHP programming language. We start with an overview of existing implementations, identifying their strengths and weaknesses. We then introduce GAP, our implementation of aspect-oriented programming for PHP that uses dynamic weaving, supports aspect genericity, and provides a framework to implement custom pointcut languages on top of it.

Sebastian Bergmann; Günter Kniesel

2006-01-01

266

Multiple input electrode gap controller  

DOEpatents

A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

Hysinger, Christopher L. (Austin, TX); Beaman, Joseph J. (Austin, TX); Melgaard, David K. (Albuquerque, NE); Williamson, Rodney L. (Albuquerque, NE)

1999-01-01

267

Brain Responses to Filled Gaps  

ERIC Educational Resources Information Center

An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine…

Hestvik, Arild; Maxfield, Nathan; Schwartz, Richard G.; Shafer, Valerie

2007-01-01

268

Closing the Teacher Quality Gap  

ERIC Educational Resources Information Center

Schools and districts rarely have a fair distribution of teacher talent. Poor children and black children are less likely to be taught by the strongest teachers and more likely to be taught by the weakest. Several districts have implemented programs to reduce the teacher quality gap. Hamilton County, Tennessee, launched an initiative that included…

Haycock, Kati; Crawford, Candace

2008-01-01

269

Amphibian cathelicidin fills the evolutionary gap of cathelicidin in vertebrate.  

PubMed

Cathelicidins comprise a family of antimicrobial peptides (AMPs) sharing a highly conserved cathelin domain, and play a central role in the innate defense against infection in most of vertebrates. But so far it has not yet been found in amphibians although a large number of other groups of AMPs have been identified. In the current work, the first amphibian cathelicidin (cathelicidin-AL) has been characterized from the frog skin of Amolops loloensis. Cathelicidin-AL (RRSRRGRGGGRRGGSGGRGGRGGGGRSGAGSSIAGVGSRGGGGGRHYA) is a cationic peptide containing 48 amino acid residues (aa) with 12 basic aa and no acidic aa. The chemical synthesized peptide efficiently killed bacteria and some fungal species including clinically isolated drug-resistance microorganisms. The cDNA encoding cathelicidin-AL precursor was cloned from the skin cDNA library of A. loloensis. As other cathelicidins, the precursor of cathelicidin-AL also contains highly conserved anionic cathelin domain of cysteine proteinase inhibitor followed by the AMP fragment at C-terminus. Phylogenetic analysis revealed that as connecting link, the amphibian cathelicidin predates reptilia but postdates fish cathelicidin. The peptide purification combined with gene cloning results confirms the presence of cathelicidin in amphibians and filled the evolutionary gap of cathelicidin in vertebrate, considering amphibians' special niche as the animals bridging the evolutionary land-water gap. PMID:22009138

Hao, Xue; Yang, Hailong; Wei, Ling; Yang, Shilong; Zhu, Wenjuan; Ma, Dongying; Yu, Haining; Lai, Ren

2012-08-01

270

Solidphase reagents for the determination of anionic surfactants in water  

Microsoft Academic Search

Sorption-spectrometric methods for the determination of anionic surfactants (A Surf) in natural and waste water using silica gel (SG) loaded with ion-pair associates of high molecular weight quaternary ammonium salts (QAS) and anionic dyes were developed. For this purpose, the interaction of Methyl Orange (MO), sodium picrate (Picr) and fluorescein (Fl) with didecylaminoethyl-b- tridecylammonium iodide (I) and N-methyl-N,N,NA,NA,NA- pentadecylethyldiammonium diiodide

O. A. Zaporozhets; O. Yu. Nadzhafova; S. A. Dolenko; T. Ye Keda; V. V. Sukhan

1998-01-01

271

Anion Separation by Selective Crystallization of Metal-Organic-Frameworks  

Microsoft Academic Search

A novel approach for the separation of anions from aqueous mixtures was demonstrated, which involves their selective crystallization with metal-organic frameworks (MOFs) containing urea functional groups. Self-assembly of Zn{sup 2+} with the N,N-bis(m-pyridyl)urea (BPU) linker results in the formation of one-dimensional MOFs including various anions for charge balance, which interact to different extents with the zinc nodes and the urea

Radu Custelcean; Radu; Bruce A. Moyer

2006-01-01

272

Gas-Grain Models for Interstellar Anion Chemistry  

NASA Technical Reports Server (NTRS)

Long-chain hydrocarbon anions C(sub n) H(-) (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with n(sub H2) approx > / cubic cm). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C6H(-) anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C6O, C7O, HC6O, and HC7O, the abundances of which depend on the assumed branching ratios for associative electron detachment

Cordiner, M. A.; Charnely, S. B.

2012-01-01

273

Characterization of a Saturated and Flexible Aliphatic Polyol Anion Receptor  

SciTech Connect

Nature employs flexible molecules to bind anions in a variety of physiologically important processes whereas supramolecular chemists have been designing rigid substrates that minimize or eliminate intramolecular hydrogen bond interactions to carry out anion recogni-tion. Herein, the association of a flexible polyhydroxy alkane with chloride ion is described and the bound re-ceptor is characterized by infrared and photoelectron spectroscopy in the gas phase, computations, and its bind-ing constant as a function of temperature in acetonitrile.

Shokri, Alireza; Schmidt, Jacob C.; Wang, Xue B.; Kass, Steven R.

2012-10-17

274

Lactate metabolism in anoxic turtles: an integrative review.  

PubMed

Painted turtles can accumulate lactic acid to extremely high concentrations during long-term anoxic submergence, with plasma lactate exceeding 200 mmol l(-1). The aims of this review are twofold: (1) To summarize aspects of lactate metabolism in anoxic turtles that have not been reviewed previously and (2) To identify gaps in our knowledge of turtle lactate metabolism by comparing it with lactate metabolism during and after exercise in other vertebrates. The topics reviewed include analyses of lactate's fate during recovery, the effects of temperature on lactate accumulation and clearance, the interaction of activity and recovery metabolism, fuel utilization during recovery, stress hormone responses during and following anoxia, and cellular lactate transport mechanisms. An analysis of lactate metabolism in anoxic turtles in the context of the 'lactate shuttle' hypothesis is also presented. PMID:17940776

Warren, Daniel E; Jackson, Donald C

2008-02-01

275

Anionic Dicyanamide Frameworks as Possible Components of Multifunctional Materials  

SciTech Connect

The dicyanamide anion, [N(CN){sub 2}]{sup -} (hereafter abbreviated dca), has been shown to be a versatile building block for the assembly of coordination polymers which are components of molecular superconductors, magnets and conducting/magnetic hybrid materials. Significantly different anion topologies have been observed. We report the first study of the use of alkylammonium cations as templates for [M(dca){sub 3}]{sup -} (M = Mn and Ni) anionic networks, including a novel three-dimensional anionic structure in the (Bu{sub 3}NH){sub 4}[Mn{sub 3}(dca){sub 10}] salt. The molecular superconductors with the highest superconducting transition temperature, {kappa}-(ET){sub 2}[Cu(dca)X] [X = Cl, Br; ET, commonly abbreviated as BEDT-TTF, is bis(ethylenedithio)tetrathiafulvalene] contain chains of diamagnetic Cu(I) ions linked by dca anions. The successful introduction of magnetically active transition metals into the charge-compensating dca layer will also be discussed. Specifically, we have synthesized and characterized the (ET){sub 2}[Mn(dca){sub 3}] salt that contain a novel triangular, spin frustrated, anion lattice separated by conducting layers of ET radical cations.

Schlueter, J. A. [Argonne National Laboratory (ANL); Geiser, U. [Argonne National Laboratory (ANL); Manson, Jamie L [ORNL

2004-01-01

276

Volume-induced increase of anion permeability in human lymphocytes  

PubMed Central

Peripheral blood mononuclear cells (PBM) readjust their volumes after swelling in hypotonic media. This regulatory volume decrease (RVD) is associated with a loss of cellular K+ and is thought to be promoted by an increased permeability to this ion. In contrast, no change in volume was observed when K+ permeability of PBM in isotonic media was increased to comparable or higher levels using valinomycin. Moreover, valinomycin-induced 86Rb+ loss in K+-free medium was considerably slower than in K+-rich medium. These results suggest that anion conductance limits net salt loss in isotonic media. Direct measurements of relative conductance confirmed that in volume-static cells, anion conductance is lower than that of K+. In volume-regulating cells depolarization occurred presumably as a result of increased anion conductance. Accordingly, the efflux of 36Cl from PBM was markedly increased by hypotonic stress. Since both membrane potential and intracellular 36Cl concentration are reduced in hypotonically swollen cells, the increased efflux is probably due to a change in Cl- permeability. Anions and cations seem to move independently through the volume-induced pathways: the initial rate of 86Rb uptake in swollen cells was not affected by replacement of external Cl- by SO=4; conversely, 36Cl fluxes were unaffected by substitution of K+ by Na+. The data indicate that anion conductance is rate-determining in salt and water loss from PBM. An increase in anion conductance is suggested to be the critical step of RVD of human PBM. PMID:7175489

1982-01-01

277

Hemibonding of hydroxyl radical and halide anion in aqueous solution.  

PubMed

Molecular geometries and properties of the possible reaction products between the hydroxyl radical and the halide anions in aqueous solution were investigated. The formation of two-center three-electron bonding (hemibonding) between the hydroxyl radical and halide anions (Cl, Br, I) was examined by density functional theory (DFT) calculation with a range-separated hybrid (RSH) exchange-correlation functional. The long-range corrected hybrid functional (LC-?PBE), which have given quantitatively satisfactory results for odd electron systems and excited states, was examined by test calculations for dihalogen radical anions (X(2)(-); X = Cl, Br, I) and hydroxyl radical-water clusters. Equilibrium geometries with hemibonding between the hydroxyl radical and halide anions were located by including four hydrogen-bonded water molecules. Excitation energies and oscillator strengths of ?-?* transitions calculated by the time-dependent DFT method showed good agreement with observed values. Calculated values of the free energy of reaction on the formation of hydroxyl halide radical anion from the hydroxyl radical and halide anion were endothermic for chloride but exothermic for bromide and iodide, which is consistent with experimental values of equilibrium constants. PMID:22136588

Yamaguchi, Makoto

2011-12-29

278

Grain boundary mobility in anion doped MgO  

NASA Technical Reports Server (NTRS)

Certain anions OH(-), F(-) and Gl(-) are shown to enhance grain growth in MgO. The magnitude of their effect decreases in the order in which the anions are listed and depends on their location (solid-solution, second phase) in the MgO lattice. As most anions exhibit relatively high vapor pressures at sintering temperatures, they retard densification and invariably promote residual porosity. The role of anions on grain growth rates was studied in relation to their effect on pore mobility and pore removal; the atomic process controlling the actual rates was determined from observed kinetics in conjunction with the microstructural features. With respect to controlling mechanisms, the effects of all anions are not the same. OH(-) and F(-) control behavior through creation of a defect structure and a grain boundary liquid phase while Cl(-) promotes matter transport within pores by evaporation-condensation. Studies on an additional anion, S to the minus 2nd power gave results which were no different from undoped MgO, possibly because of evaporative losses during hot pressing. Hence, the effect of sulphur is negligible or undetermined.

Kapadia, C. M.; Leipold, M. H.

1973-01-01

279

Paying Attention to Dietary Cation-Anion Balance Can Mean More Milk and Fewer Metabolic Problems  

E-print Network

. Research demonstrates that dry cows can benefit from a mild systemic acidosis at calv- ing, resulting in improved bone calcium mobilization. Lactating cows benefit from a mild systemic alkalosis that buffers

Liskiewicz, Maciej

280

Palytoxin Induces Functional Changes of Anion Transport in Red Blood Cells: Metabolic Impact  

Microsoft Academic Search

Palytoxin (PTX) is classified as one of the most powerful marine biotoxins (of high molecular weight and no protein origin)\\u000a because it is able to interact strongly with important cellular structures influencing their function in different biological\\u000a processes. This study of the effects of PTX on red blood cells (RBC) extends the knowledge about its toxicity, which concerns\\u000a not only

Silvana FicarraAnnamaria; Annamaria Russo; Francesca Stefanizzi; Mario Mileto; Davide Barreca; Ersilia Bellocco; Giuseppina Laganà; Ugo Leuzzi; Bruno Giardina; Antonio Galtieri; Ester Tellone

2011-01-01

281

Gap Test Calibrations and Their Scaling  

NASA Astrophysics Data System (ADS)

Common tests for measuring the threshold for shock initiation are the NOL large scale gap test (LSGT) with a 50.8-mm diameter donor/gap and the expanded large scale gap test (ELSGT) with a 95.3-mm diameter donor/gap. Despite the same specifications for the explosive donor and polymethyl methacrylate (PMMA) gap in both tests, calibration of shock pressure in the gap versus distance from the donor scales by a factor of 1.75, not the 1.875 difference in their sizes. Recently reported model calculations suggest that the scaling discrepancy results from the viscoelastic properties of PMMA in combination with different methods for obtaining shock pressure. This is supported by the consistent scaling of these donors when calibrated in water-filled aquariums. Calibrations with water gaps will be provided and compared with PMMA gaps. Scaling for other donor systems will also be provided. Shock initiation data with water gaps will be reviewed.

Sandusky, Harold

2011-06-01

282

Air Gap Effects in LX-17  

SciTech Connect

Three experiments done over twenty years on gaps in LX-17 are reported. For the detonation front moving parallel to the gaps, jets of gas products were seen coming from the gaps at velocities greater than the detonation velocity. A case can be made that the jet velocity increased with gap thickness but the data is scattered. For the detonation front moving transverse to the gap, time delays were seen. The delays roughly increase with gap width, going from 0-70 ns at 'zero gap' to around 300 ns at 0.5-1 mm gap. Larger gaps of up to 6 mm width almost certainly stopped the detonation, but this was not proved. Real-time resolution of the parallel jets and determination of the actual re-detonation or failure in the transverse case needs to be done in future experiments.

Souers, P C; Ault, S; Avara, R; Bahl, K L; Boat, R; Cunningham, B; Gidding, D; Janzen, J; Kuklo, D; Lee, R; Lauderbach, L; Weingart, W C; Wu, B; Winer, K

2005-09-26

283

Metabolism of Bifidobacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genus Bifidobacterium possesses a unique fructose-6-phosphate phosphoketolase pathway employed to ferment carbohydrates. Much metabolic research on bifidobacteria has focused on oligosaccharide metabolism as these carbohydrate polymers are available in their otherwise nutrient-limited habitats....

284

Endocrine and Metabolic Disorders  

MedlinePLUS

Printer-Friendly Home » Health Status » Health Indicators Endocrine and Metabolic Disorders Endocrine disorders involve the body’s over- or under-production of certain hormones, while metabolic disorders affect the body’s ability to ...

285

The interaction of an anionic photoreactive probe with the anion transport system of the human red blood cell.  

PubMed

N-(4-azido-2-nitrophenyl)-2-aminoethyl[35S]sulfonate is employed as a photoreactive probe for the anion transport system in the human erythrocyte. In the dark and at 37 degrees C the probe penetrates the membrane via a pathway sensitive to specific inhibitors of anion permeability. It reversibly inhibits sulfate and chloride fluxes but the inhibition is reduced by higher concentrations of sulfate. Upon photolysis to produce a reactive nitrene (at 0 degrees C to minimize penetration), the probe inhibition of anion permeability. Under appropriate conditions the degree of inhibition after photoactivation (irreversible) is almost the same as that in the dark (reversible). The binding sites for the radioactive probe are largely found in proteins of 95 000 apparent molecular weight (band 3). After pronase treatment of the labelled cells, most of the probe is found in a 65 000 molecular weight segment derived from the 95 000 molecular weight protein. In this respect the photoreactive probe resembles another potent irreversible inhibitor of anion transport, 4, 4'-diisothiocyano-2, 2' stilbene disulfonate. In fact, most of the binding sites for each probe are common to both. Thus, in the dark, the azido derivative protects the anion system from inhibition by DIDS and substantially reduces the binding of DIDS to band 3 protein. Conversely, pretreatment with DIDS substantially reduces the binding of the photoreactive probe to the same protein. The fact that an apparent substrate for the anion permeation system competes for binding sites with a specific non-penetrating inhibitor of anion permeability suggests that the inhibitory and transport sites may be closely related and implicates the 95 000 molecular weight protein as the element of the anion transport system which contains the substrate binding site. PMID:999926

Cabantchik, Z I; Knauf, P A; Ostwald, T; Markus, H; Davidson, L; Breuer, W; Rothstein, A

1976-12-01

286

Gaps"  

ERIC Educational Resources Information Center

This study investigated the effect of daily quizzes on the performance of college students. Students in an introductory psychology course used their own wireless-enabled devices to take short Internet-based quizzes at the beginning of every class. The quiz items were drawn approximately equally from material covered in the readings and the…

What Works Clearinghouse, 2013

2013-01-01

287

Book Review METABOLISM: INTERFACE  

E-print Network

of the regulation of carbohydrate, lipid and amino acid metabolism. Current understanding of different formsBook Review 797 METABOLISM: INTERFACE BETWEEN INTEGRATIVE PHYSIOLOGY AND FUNCTIONAL GENOMICS Functional metabolism: regulation and adaptation Edited by Kenneth B. Storey Wiley Press (2004) pp. 616. ISBN

Storey, Kenneth B.

288

Humidity and Insect Metabolism  

Microsoft Academic Search

ENTOMOLOGISTS have suggested that certain insects may show a greater rate of metabolism in dry air than in moist at the same temperature. They believe that such increased metabolism should cause a greater production of metabolic water, to compensate for evaporation from the insect's body, and maintain a constant ratio of water to dry matter at different atmospheric humidities. This

Kenneth Mellanby

1936-01-01

289

Metabolic bone disease  

Microsoft Academic Search

Bone is a complex organ that is highly metabolically active, particularly in children. Normal metabolism is dependent upon the three main elements, matrix, mineral and cells that are integral components of bone. In addition, there are several humoral factors that also influence bone. Abnormalities in any of these components can give rise to metabolic bone disease. Abnormalities of mineralisation are

Jeremy Allgrove

2011-01-01

290

Electronic gap sensor and method  

DOEpatents

An apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces.

Williams, Robert S. (Fairfield, OH); King, Edward L. (Trenton, OH); Campbell, Steven L. (Middletown, OH)

1991-01-01

291

Electronic gap sensor and method  

DOEpatents

Disclosed are an apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. 5 figures.

Williams, R.S.; King, E.L.; Campbell, S.L.

1991-08-06

292

The role of dietary calcium concentration in the use of anionic salts to prevent parturient paresis in dairy cows.  

PubMed

The role of dietary calcium concentration during the feeding of anionic salts (AS) was reviewed. Hypocalcaemia is still the major cause of parturient paresis in dairy cows. Feeding AS is an established method for preventing severe hypocalcaemia by activating the calcium metabolism in the last two to three weeks before parturition by inducing a metabolic acidosis. In compensation for this acidosis, the organism increases the concentrations of ionised Ca [Ca2+] in the blood. This increase leads to an increasing excretion of calcium via the urine, which is ensued by an increased calcium absorption in the intestine. The ongoing metabolic acidosis changed the flux of Ca. The size of the Ca pool, however, remained unchanged. As the calcium metabolism is activated by AS, it seems necessary to increase the amount of calcium that is fed to the cows. Several studies examined the impact of different dietary calcium concentrations on the acid-base balance and the calcium metabolism in cows fed anionic salts. The study designs vary concerning the amounts of calcium fed and the use of pregnant or non-pregnant cows. Only one study combined the feeding of AS with a very low amount of calcium, which fell below the daily requirements of pregnant cows in the last three weeks before parturition. In this study, the calcium balance post partum was better in the cows that were administered AS and a high calcium diet. In the other studies, the amount of calcium in the different experimental groups and the difference between the amounts of calcium fed varied greatly. As far as it was monitored in the studies, the calcium concentration of the diet did not have a significant impact on the degree of acidosis induced by AS. In pregnant cows, no significant differences in the calcium concentration in serum or urine occurred before parturition. Some of the researchers found a lower incidence of parturient paresis when cows were fed a combination of AS and a higher amount of calcium, but some other researches did not. Interestingly, the parameters of bone metabolism did not change between experimental groups. According to what is currently known, the feeding of AS to transition cows should not be combined with a dietary calcium concentration that falls below the requirement of cows in this stage of lactation. On the other hand, there is no need to increase the Ca concentration. When AS are used the dietary calcium concentration should be between 9 g and 12 g/kg dry matter. Further research is needed to investigate the role of dietary calcium regarding the use of AS for improving Ca metabolism in dairy cows around parturition. PMID:18712261

Gelfert, Carl-Christian; Staufenbiel, Rudolf

2008-01-01

293

On the coexistence of localized and extended acceptor states in high gap semiconductors  

NASA Astrophysics Data System (ADS)

Holes introduced into high gap materials by acceptor doping are often self-localized at anion sites as small polarons bound to the doping elements. The related lattice distortion lowers the hole energy; the hole levels thus tend to be deep. Electronic structure calculations of small polarons have identified, for some dopings, that such localized states can coexist with extended ones that result from the same doping. Using a scaling formalism, proposed by Emin and Holstein, it is shown that this appears to be a general phenomenon if the polaron-forming short-range hole–lattice coupling is taken into account.

Schirmer, O. F.

2015-02-01

294

The role of catalyst precursor anions in coal gasification  

SciTech Connect

The aims of the proposed project are to enrich our understanding of the roles of various aqueous soluble catalyst precursor anions on the surface electrical properties of coal and to ascertain the influence of the surface charge on the adsorption, dispersion, and activities of calcium and potassium. These goals will be achieved by impregnating a North Dakota lignite (PSOC 1482) and its demineralized derivative with calcium or potassium catalyst precursors containing acetate (CH{sub 3}COO{sup {minus}}), chloride (Cl{sup {minus}}), nitrate (NO{sub 3}{sup {minus}}), sulfate (SO{sub 4}{sup 2{minus}}), and carbonate (CO{sub 3}{sup 2{minus}}) anions. Catalyst loading will be conducted under well-controlled conditions of solution pH and ionic strength. In the last quarter, the surface charge properties of the coal was determined as a function of acetate (CH{sub 3}COO{sup {minus}}), chloride (Cl{sup {minus}}), nitrate (NO{sup 3}{sup {minus}}), carbonate (CO{sub 3}{sup 2{minus}}) or sulfate (SO{sub 4}{sup 2{minus}})concentration using the respective potassium salts of these anions. In general, low anion concentrations (10{sup {minus}3} or 10{sup {minus}2} mol/L) had little effect on the zeta potentials of the coals. However, the surface charge densities of the coal become less negative at 10-1 mol/L of the nitrate, carbonate or sulfate anions. These trends suggest that the surface charge density of the coal is controlled by the adsorption of potassium ions (K{sup +}) onto the coal particles. The net negative charge on the coal panicles creates a repulsive force between the anions and the coal surface and prevents the anions from exerting any significant effect on the coal's electrokinetic properties.

Abotsi, G.M.K.

1992-08-28

295

Energy Gaps in Graphene Nanoribbons  

Microsoft Academic Search

Based on a first-principles approach, we present scaling rules for the band\\u000agaps of graphene nanoribbons (GNRs) as a function of their widths. The GNRs\\u000aconsidered have either armchair or zigzag shaped edges on both sides with\\u000ahydrogen passivation. Both varieties of ribbons are shown to have band gaps.\\u000aThis differs from the results of simple tight-binding calculations or solutions

Young-Woo Son; Marvin L. Cohen; Steven G. Louie

2006-01-01

296

Homolumo gap and matrix model  

SciTech Connect

We discuss a dynamical matrix model by which probability distribution is associated with Gaussian ensembles from random matrix theory. We interpret the matrix M as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show that a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest occupied eigenvalue and the lowest unoccupied eigenvalue.

Andric, I.; Jonke, L.; Jurman, D.; Nielsen, H. B. [Theoretical Physics Division, Rudjer Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia); Niels Bohr Institute, Copenhagen DK 2100 (Denmark)

2008-06-15

297

Prometheus and the Keeler gap  

NASA Astrophysics Data System (ADS)

Linblad resonances with Saturn’s satellites are located at many radii in the rings. While some cause density or bending waves, others hold gap edges from spreading, like the 2:1 resonance with Mimas located at the B-ring edge, the 7:6 resonance with Janus at the A-ring edge, and the 32:31 resonance with Prometheus at the inner edge of the Keeler gap. The latter is the case of study here.Theoretically, the inner edge of the Keeler gap should have 32 regular sinusoidal lobes, where either the maximum or the minimum radius is expected to be aligned with Prometheus and rotating with its mean motion. We show that such is not the case. Fit of occultation data shows the presence of the 32:31 resonance, however, the fit residuals is as high as the amplitude of the resonance amplitude (about 2 km). Analysis of the ISS data, shows irregularities overlapping the lobes (Tiscareno et al. 2005, DPS), that follow Keplerian motion. These irregularities may be due to clumps of particles with different eccentricities than the rest of the edge particles. This phenomenon may be caused by the resonance, as it has not been observed at other circular edges were no resonance is present at their location. The ISS data also shows that the lobe’s minimum/maximum is not perfectly aligned with the longitude of Prometheus, which may be due to libration about the centre of the resonance.

Tajeddine, Radwan; Nicholson, Phillip D.; Hedman, Matthew M.; French, Richard G.; Tiscareno, Matthew S.; Burns, Joseph A.

2014-11-01

298

Direct Band Gap Wurtzite Gallium Phosphide Nanowires  

PubMed Central

The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555–690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

2013-01-01

299

A Reluctance Actuator Gap Disturbance Testbed  

E-print Network

We have designed and built a Reluctance Actuator Gap Disturbance Testbed. The testbed emulates the short stroke and long stroke interaction of modern lithography stages. The testbed can be used to impart gap disturbance ...

Meléndez H., Roberto J

2014-01-01

300

30 CFR 57.6603 - Air gap.  

Code of Federal Regulations, 2013 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

2013-07-01

301

30 CFR 56.6603 - Air gap.  

Code of Federal Regulations, 2012 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

2012-07-01

302

30 CFR 57.6603 - Air gap.  

Code of Federal Regulations, 2014 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

2014-07-01

303

30 CFR 57.6603 - Air gap.  

Code of Federal Regulations, 2011 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

2011-07-01

304

30 CFR 56.6603 - Air gap.  

Code of Federal Regulations, 2014 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

2014-07-01

305

30 CFR 57.6603 - Air gap.  

Code of Federal Regulations, 2012 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

2012-07-01

306

30 CFR 56.6603 - Air gap.  

Code of Federal Regulations, 2011 CFR

...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

2011-07-01

307

Sustained metabolic scope.  

PubMed Central

Sustained metabolic rates (SusMR) are time-averaged metabolic rates that are measured in free-ranging animals maintaining constant body mass over periods long enough that metabolism is fueled by food intake rather than by transient depletion of energy reserves. Many authors have suggested that SusMR of various wild animal species are only a few times resting (basal or standard) metabolic rates (RMR). We test this conclusion by analyzing all 37 species (humans, 31 other endothermic vertebrates, and 5 ectothermic vertebrates) for which SusMR and RMR had both been measured. For all species, the ratio of SusMR to RMR, which we term sustained metabolic scope, is less than 7; most values fall between 1.5 and 5. Some of these values, such as those for Tour de France cyclists and breeding birds, are surely close to sustainable metabolic ceilings for the species studied. That is, metabolic rates higher than 7 times RMR apparently cannot be sustained indefinitely. These observations pose several questions: whether the proximate physiological causes of metabolic ceilings reside in the digestive tract's ability to process food or in each tissue's metabolic capacity; whether ceiling values are independent of the mode of energy expenditure; whether ceilings are set by single limiting physiological capacities or by coadjusted clusters of capacities (symmorphosis); what the ultimate evolutionary causes of metabolic ceilings are; and how metabolic ceilings may limit animals' reproductive effort, foraging behavior, and geographic distribution. PMID:2315323

Peterson, C C; Nagy, K A; Diamond, J

1990-01-01

308

PhotonicPhotonicPhotonicPhotonic Band GapBand GapBand GapBand Gap MaterialsMaterialsMaterialsMaterials  

E-print Network

. YablonovitchYablonovitch 1990: Computational Demonstration of PBG (band structure) K.M. Ho, C.T. Chan, C)Computational Demonstration of PBG (band structure) K.M. Ho, C.T. Chan, C.M.K.M. Ho, C.T. Chan, C.M. SoukoulisSoukoulis, PRLPhotonicPhotonicPhotonicPhotonic Band GapBand GapBand GapBand Gap Materials

John, Sajeev

309

Spark gap with low breakdown voltage jitter  

DOEpatents

Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

Rohwein, Gerald J. (Albuquerque, NM); Roose, Lars D. (Albuquerque, NM)

1996-01-01

310

Spark gap with low breakdown voltage jitter  

DOEpatents

Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed. 13 figs.

Rohwein, G.J.; Roose, L.D.

1996-04-23

311

Gap Year: Time off, with a Plan  

ERIC Educational Resources Information Center

A gap year allows people to step off the usual educational or career path and reassess their future. According to people who have taken a gap year, the time away can be well worth it. This article can help a person decide whether to take a gap year and how to make the most of his time off. It describes what a gap year is, including its pros and…

Torpey, Elka Maria

2009-01-01

312

Optimum band gap of a thermoelectric material  

Microsoft Academic Search

Transport properties of direct-gap semiconductors are calculated in order to find the best thermoelectrics. Previous calculations on semiconductors with indirect band gaps found that the best thermoelectrics had gaps equal to [ital nk][sub [ital B]T], where [ital n]=6[minus]10 and [ital T] is the operating temperature of the thermoelectric device. Here we report similar calculations on direct-gap materials. We find that

J. O. Sofo; G. D. Mahan

1994-01-01

313

REACTIVITY OF ANIONS IN INTERSTELLAR MEDIA: DETECTABILITY AND APPLICATIONS  

SciTech Connect

We propose a general rule to distinguish between detectable and undetectable astronomical anions. We believe that only few anions live long enough in the interstellar medium and thus can be detected. Our method is based on quantum mechanical calculations capable of describing accurately the evolution of electronic states during chemical processes. The still not fully understood reactivity at low temperatures is discussed considering non-adiabatic effects. The role of excited states has usually been neglected in previous works which basically focused on the ground electronic state for interpretations of experimental observations. Here, we deal with unsaturated carbon chains (e.g., C{sub n} H{sup -}), which show a high density of electronic states close to their corresponding ground electronic states, complex molecular dynamics, and non-adiabatic phenomena. Our general rule shows that it is not sufficient that anions exist in the gas phase (in the laboratory) to be present in media such as astrophysical media, since formation and decomposition reactions of these anions may allow the population of anionic electronic states to autodetach, forming neutrals. For C{sub n} H, reactivity depends strongly on n, where long and short chains behave differently. Formation of linear chains is relevant.

Senent, M. L. [Departamento de Quimica y Fisica Teoricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid E-28006 (Spain); Hochlaf, M., E-mail: senent@iem.cfmac.csic.es, E-mail: hochlaf@univ-mlv.fr [Laboratoire de Modelisation et Simulation Multi Echelle, Universite Paris-Est, MSME UMR 8208 CNRS, 5 boulevard Descartes, F-77454 Marne-la-Vallee (France)

2013-05-01

314

Reversible Intercalation of Fluoride-Anion Receptor Complexes in Graphite  

NASA Technical Reports Server (NTRS)

We have demonstrated a route to reversibly intercalate fluoride-anion receptor complexes in graphite via a nonaqueous electrochemical process. This approach may find application for a rechargeable lithium-fluoride dual-ion intercalating battery with high specific energy. The cell chemistry presented here uses graphite cathodes with LiF dissolved in a nonaqueous solvent through the aid of anion receptors. Cells have been demonstrated with reversible cathode specific capacity of approximately 80 mAh/g at discharge plateaus of upward of 4.8 V, with graphite staging of the intercalant observed via in situ synchrotron X-ray diffraction during charging. Electrochemical impedance spectroscopy and B-11 nuclear magnetic resonance studies suggest that cointercalation of the anion receptor with the fluoride occurs during charging, which likely limits the cathode specific capacity. The anion receptor type dictates the extent of graphite fluorination, and must be further optimized to realize high theoretical fluorination levels. To find these optimal anion receptors, we have designed an ab initio calculations-based scheme aimed at identifying receptors with favorable fluoride binding and release properties.

West, William C.; Whitacre, Jay F.; Leifer, Nicole; Greenbaum, Steve; Smart, Marshall; Bugga, Ratnakumar; Blanco, Mario; Narayanan, S. R.

2007-01-01

315

A versatile tripodal amide receptor for the encapsulation of anions or hydrated anions via formation of dimeric capsules.  

PubMed

A bowl-shaped tripodal receptor with an appropriately positioned amide functionality on the benzene platform and electron-withdrawing p-nitrophenyl terminals (L(1)) has been designed, synthesized, and studied for the anion binding properties. The single-crystal X-ray crystallographic analysis on crystals of L(1) with tetrabutylammonium salts of nitrate (1), acetate (2), fluoride (3), and chloride (4) obtained in moist dioxane medium showed encapsulation of two NO(3)(-), [(AcO)(2)(H(2)O)(4)](2-), [F(2)(H(2)O)(6)](2-), and [Cl(2)(H(2)O)(4)](2-) respectively as the anionic guests inside the staggered dimeric capsular assembly of L(1). The p-nitro substitution in the aryl terminals assisted the formation of dimeric capsular assembly of L(1) exclusively upon binding/encapsulating above different guests. Though L(1) demonstrates capsule formation upon anion or hydrated anion complexation for all of the anions studied here, its positional isomer with the o-nitro-substituted tripodal triamide receptor L(2) selectively formed the dimeric capsular assembly upon encapsulation of [F(2)(H(2)O)(6)](2-) and noncapsular aggregates in the cases of other anions such as Cl(-), NO(3)(-), and AcO(-). Interestingly, structural investigations upon anion exchange of the complexes revealed that both isomers have selectivity toward the formation of a [F(2)(H(2)O)(6)](2-) encapsulated dimeric capsule. In contrast, solution-state (1)H NMR titration studies of L(1) and L(2) in DMSO-d(6) with AcO(-) indicated 1:3 (host:guest) binding. PMID:20030371

Arunachalam, M; Ghosh, Pradyut

2010-02-01

316

Generation Gaps in Engineering? David J. Kim  

E-print Network

Generation Gaps in Engineering? by David J. Kim B.S., Computer Science and Engineering;3 Generation Gaps in Engineering? by David J. Kim Submitted to the System Design and Management Program on May in Engineering and Management ABSTRACT There is much enthusiastic debate on the topic of generation gaps

Gabrieli, John

317

Reducing the White-Nonwhite Achievement Gap.  

ERIC Educational Resources Information Center

It is well documented that there continues to be a gap between white and nonwhite student achievement. A study develops and tests a measure of white-nonwhite achievement gap reduction. The ultimate purpose is to use the measure as the dependent variable in a qualitative study of what works in reducing the gap. The strategy used in addressing this…

Ramey, Madelaine

318

Low band gap polymers for organic photovoltaics  

Microsoft Academic Search

Low band gap polymer materials and their application in organic photovoltaics (OPV) are reviewed. We detail the synthetic approaches to low band gap polymer materials starting from the early methodologies employing quinoid homopolymer structures to the current state of the art that relies on alternating copolymers of donor and acceptor groups where strategies for band gap design are possible. Current

Eva Bundgaard; Frederik C. Krebs

2007-01-01

319

Closing the Salary Gap Noreen Rossi  

E-print Network

anxiety and prevents women from negotiating in the first place is not knowing how the conversationClosing the Salary Gap Noreen Rossi Dawn Misra #12;Overview · Evidence of salary gap for women · What contributes to the gap? ­ Institutional barriers ­ Women's own practices · Sharing stories · Best

Finley Jr., Russell L.

320

Gapping in Farsi: A Crosslinguistic Investigation  

ERIC Educational Resources Information Center

This dissertation explores a longstanding challenge in work on gapping through the empirical lens of gapping in Farsi (the Tehrani variant of Modern Persian). While gapping has much in common with more uncontroversial elliptical constructions such as VPE and sluicing, it also differs from ellipsis in ways that accounts combining TP or CP…

Farudi, Annahita

2013-01-01

321

Subgroup Achievement and Gap Trends: Oklahoma, 2010  

ERIC Educational Resources Information Center

This paper profiles the student subgroup achievement and gap trends in Oklahoma for 2010. Oklahoma made progress in narrowing achievement gaps for most major subgroups on the End-of-Instruction (EOI) test in Algebra I. Trends in achievement gaps could not be determined for other grades in math, or for any grades in reading, because the state…

Center on Education Policy, 2010

2010-01-01

322

Autodetachment spectroscopy of a molecular anion using a diode laser  

SciTech Connect

Autodetachment spectroscopy, a technique for studying molecular anions, has been applied in the past using color-center lasers or visible dye lasers. In the present work, the technique has been extended to employ a relatively weak diode laser. Laser radiation drives an infrared vibrational-rotational transition in the molecular anion NH . The vibrationally excited anion autodetaches, and the resulting fast neutral is detected. The P{sub 1} (6.5,e{minus} > e) transition in the fundamental (1 < {minus}0) band of NH has been observed near 2806 cm{sup {minus}1} with a signal to noise ratio of 15:1 with a 30-s averaging time. The present experiment has fewer than 500 ions of a single quantum state in the apparatus at once, interacting with 5 microwatts of laser power. Future instrumental improvements can yield orders of magnitude improvement in sensitivity.

Marawar, R.W.; Cowles, D.C.; Keeler, R.E.; White, A.P.; Farley, J.W. [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Physics

1994-12-31

323

Photoelectron spectroscopic and computational study of hydrated pyrimidine anions.  

PubMed

The stabilization of the pyrimidine anion by the addition of water molecules is studied experimentally using photoelectron spectroscopy of mass-selected hydrated pyrimidine clusters and computationally using quantum-mechanical electronic structure theory. Although the pyrimidine molecular anion is not observed experimentally, the addition of a single water molecule is sufficient to impart a positive electron affinity. The sequential hydration data have been used to extrapolate to -0.22 eV for the electron affinity of neutral pyrimidine, which agrees very well with previous observations. These results for pyrimidine are consistent with previous studies of the hydrated cluster anions of uridine, cytidine, thymine, adenine, uracil, and naphthalene. This commonality suggests a universal effect of sequential hydration on the electron affinity of similar molecules. PMID:24937484

Kelly, John T; Xu, Shoujun; Graham, Jacob; Nilles, J Michael; Radisic, Dunja; Buonaugurio, Angela M; Bowen, Kit H; Hammer, Nathan I; Tschumper, Gregory S

2014-12-26

324

Analysis of anions in geological brines using ion chromatography  

SciTech Connect

Ion chromatographic procedures for the determination of the anions bromide, sulfate, nitrite, nitrate, phosphate, and iodide in brine samples have been developed and are described. The techniques have been applied to the analysis of natural brines, and geologic evaporites. Sample matrices varied over a range from 15,000 mg/L to 200,000 mg/L total halogens, nearly all of which is chloride. The analyzed anion concentrations ranged from less than 5 mg/L in the cases of nitrite, nitrate, and phosphate, to 20,000 mg/L in the case of sulfate. A technique for suppressing chloride and sulfate ions to facilitate the analysis of lower concentration anions is presented. Analysis times are typically less than 20 minutes for each procedure and the ion chromatographic results compare well with those obtained using more time consuming classical chemical analyses. 10 references, 14 figures.

Merrill, R.M.

1985-03-01

325

Anionic solid lipid nanoparticles supported on protamine/DNA complexes  

NASA Astrophysics Data System (ADS)

The objective of this study was to design novel anionic ternary nanoparticles for gene delivery. These ternary nanoparticles were equipped with protamine/DNA binary complexes (150-200 nm) as the support, and the anionic formation was achieved by absorption of anionic solid lipid nanoparticles (<=20 nm) onto the surface of the binary complexes. The small solid lipid nanoparticles (SLNs) were prepared by a modified film dispersion-ultrasonication method, and adsorption of the anionic SLNs onto the binary complexes was typically carried out in water via electrostatic interaction. The formulated ternary nanoparticles were found to be relatively uniform in size (257.7 ± 10.6 nm) with a 'bumpy' surface, and the surface charge inversion from 19.28 ± 1.14 mV to -17.16 ± 1.92 mV could be considered as evidence of the formation of the ternary nanoparticles. The fluorescence intensity measurements from three batches of the ternary nanoparticles gave a mean adsorption efficiency of 96.75 ± 1.13%. Circular dichroism spectra analysis showed that the protamine/DNA complexes had been coated by small SLNs, and that the anionic ternary nanoparticles formed did not disturb the construction of the binary complexes. SYBR Green I analysis suggested that the ternary nanoparticles could protect the DNA from nuclease degradation, and cell viability assay results showed that they exhibit lower cytotoxicity to A549 cells compared with the binary complexes and lipofectamine. The transfection efficiency of the ternary nanoparticles was better than that of naked DNA and the binary complexes, and almost equal to that of lipofectamine/DNA complexes, as revealed by inversion fluorescence microscope observation. These results indicated that the anionic ternary nanoparticles could facilitate gene transfer in cultured cells, and might alleviate the drawbacks of the conventional cationic vector/DNA complexes for gene delivery in vivo.

Ye, Jiesheng; Wang, Aihua; Liu, Chunxi; Chen, Zhijin; Zhang, Na

2008-07-01

326

EFFECTS OF SELECTED ANTI-TUMOR-PROMOTING CHEMICALS ON METABOLIC COOPERATION BETWEEN CHINESE HAMSTER V79 CELLS  

EPA Science Inventory

Many tumor-promoting chemicals inhibit gap junctional communication between cells. we investigated the possibility that antipromoting chemicals may act inversely and enhance gap junctional communication. he V79/metabolic cooperation assay is an in vitro test that measures pp junc...

327

Photoelectron spectroscopy of boron aluminum hydride cluster anions.  

PubMed

Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, BxAlyHz(-), were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms. PMID:24784280

Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H; Li, Xiang; Kiran, Boggavarapu; Kandalam, Anil K

2014-04-28

328

Time-dependent Anion Chemistry in the CSE IRC+10216  

NASA Astrophysics Data System (ADS)

Following the spectral characterization of C-chain anions, in the Harvard microwave laboratory, we have discovered 6 anions in the envelope of the C-rich star IRC+10216 and set limits to the abundance of two others. The anions we studied in this source range from CCH- to C8H- and from CN- to C5N- [1,2,3]. Anion abundances are low and the rotational lines weak, even in favorable cases. Two years ago, we have been able to map C6H- in IRC+10216, with the PdB interferometer, and to show that it is located, like the C6H radical, in a hollow shell. The angular resolution of the observations (5) and the S/N ratio were however insufficient to spatially differentiate the anion from the radical. Taking advantage of the recent installation of a wide-band correlator on PdBI, we have re-observed with a twice higher resolution the 83 GHz line of C6H- , as well as nearby lines of C5N-, C4H-, C2H- and of several C-chain molecules and radicals. Except for CCH-, all those species are detected and we are currently analyzing their distributions and abundances. Chemistry models, based on the electron radiative attachment theory developed by Herbst and collaborators, predict that anions and parent radicals peak at different radii in the expanding CSE[4]. Predicted radial shifts range from a few arcsec, for C6H-, to more than 10 (500 yr) for C4H- and CN-. We know, from previous single-dish observations, that the actual abundances of C4H- and CN- , relative to C4H and CN, differ by orders of magnitude from radiative attachment model predictions, while those of the long anions, C6H- and C8H agree well with predictions. The new interferometric observations, allied to single-dish data, allow us to measure the formation/destruction time of the different species and to set constraints on the rates of electron radiative attachment, rates which, so far, are only crudely evaluated through the statistical theory. The relatively high abundances of CN-, C3N - and C5N - , compared to CCH-, C4H - and C6H-, suggest that other routes, such as the reaction of N atoms with large C-chain anions, may proceed efficiently.

Guelin, M.; Agundez, M.; Cernicharo, J.; Gottlieb, C.; McCarthy, M.; Thaddeus, P.

2011-05-01

329

Photoelectron spectroscopy of boron aluminum hydride cluster anions  

SciTech Connect

Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, B{sub x}Al{sub y}H{sub z}{sup ?}, were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms.

Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H., E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Li, Xiang [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States)] [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States); Kiran, Boggavarapu, E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K. [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)] [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)

2014-04-28

330

A theoretical study of ternary indole-cation-anion complexes.  

PubMed

The simultaneous interactions of an anion and a cation with a ? system were investigated by MP2 and M06-2X theoretical calculations. Indole was chosen as a model ? system for its relevance in biological environments. Two different orientations of the anion, interacting with the N-H and with the C-H groups of indole, were considered. The four cations (Na(+), NH4(+), C(NH2)3(+) and N(CH3)4(+)) and the four anions (Cl(-), NO3(-), HCOO(-) and BF4(-)) included in the study are of biological interest. The total interaction energy of the ternary complexes was calculated and separated into its two- and three-body components and all of them are further divided into their electrostatic, exchange, repulsion, polarization and dispersion contributions using the local molecular orbital-energy decomposition analysis (LMO-EDA) methodology. The binding energy of the indole-cation-anion complexes depends on both ions, with the cation having the strongest effect. The intense cation-anion attraction determines the geometric and energetic features in all ternary complexes. These structures, with both ions on the same side of the ? system, show an anti-cooperative interaction. However, the interaction is not only determined by electrostatics, but also the polarization contribution is important. Specific interactions like the one established between the anion and the N-H group of indole or the proton transfer between an acidic cation and a basic anion play a significant role in the energetics and the structure of particular complexes. The presence of the polar solvent as modelled with the polarizable continuum model (PCM) does not seem to have a significant effect on the geometry of the ternary complexes, but drastically weakens the interaction energy. Also, the strength of the interaction is reduced at a faster rate when the anion is pushed away, compared to the results obtained in the gas phase. The combination of PCM with the addition of one water molecule indicates that the PCM method properly reproduces the main energetic and geometrical changes, even at the quantitative level, but the explicit hydration allows refining the solvent effect and detecting cases that do not follow the general trend. PMID:25296040

Carrazana-García, Jorge A; Cabaleiro-Lago, Enrique M; Campo-Cacharrón, Alba; Rodríguez-Otero, Jesús

2014-12-01

331

Hydrotalcite-like compounds obtained by anion exchange reactions  

Microsoft Academic Search

The synthesis of nickel aluminium hydroxypicrate, [Ni3Al(OH)8] (C6O7N3H2)·nH2O, and lithium aluminium hydroxypicrate, [Al2Li(OH)6] (C6O7N3H2)·nH2O by anion exchange is described. Picric acid and the corresponding hydroxycarbonates were used as starting materials. The new compounds were characterized by chemical analyses, electron microscopy, infrared spectroscopy and X-ray diffraction. The results obtained indicate that both are hydrotalcite-like compounds where the picrate anion lies between

M. A. Ulibarri; M. J. Hernandez; J. Cornejo

1991-01-01

332

Reactivity of hypotaurine and cysteine sulfinic acid toward carbonate radical anion and nitrogen dioxide as explored by the peroxidase activity of Cu,Zn superoxide dismutase and by pulse radiolysis.  

PubMed

Hypotaurine and cysteine sulfinic acid are known to be readily oxidized to the respective sulfonates, taurine and cysteic acid, by several oxidative agents that may be present in biological systems. In this work, the relevance of both the carbonate anion and nitrogen dioxide radicals in the oxidation of hypotaurine and cysteine sulfinic acid has been explored by the peroxidase activity of Cu,Zn superoxide dismutase (SOD) and by pulse radiolysis. The extent of sulfinate oxidation induced by the system SOD/H2O2 in the presence of bicarbonate (CO3(•-) generation), or nitrite ((•)NO2 generation) has been evaluated. Hypotaurine is efficiently oxidized by the carbonate radical anion generated by the peroxidase activity of Cu,Zn SOD. Pulse radiolysis studies have shown that the carbonate radical anion reacts with hypotaurine more rapidly (k = 1.1 × 10(9) M(-1)s(-1)) than nitrogen dioxide (k = 1.6 × 10(7) M(-1)s(-1)). Regarding cysteine sulfinic acid, it is less reactive with the carbonate radical anion (k = 5.5 × 10(7) M(-1)s(-1)) than hypotaurine. It has also been observed that the one-electron transfer oxidation of both sulfinates by the radicals is accompanied by the generation of transient sulfonyl radicals (RSO2(•)). Considering that the carbonate radical anion could be formed in vivo at high level from bicarbonate, this radical can be included in the oxidants capable of performing the last metabolic step of taurine biosynthesis. Moreover, the protective effect exerted by hypotaurine and cysteine sulfinate on the carbonate radical anion-mediated tyrosine dimerization indicates that both sulfinates have scavenging activity towards the carbonate radical anion. However, the formation of transient reactive intermediates during sulfinate oxidation by carbonate anion and nitrogen dioxide radical may at the same time promote oxidative reactions. PMID:25156684

Baseggio Conrado, A; D'Angelantonio, M; Torreggiani, A; Pecci, L; Fontana, M

2014-11-01

333

Gap Test Calibrations And Their Scalin  

NASA Astrophysics Data System (ADS)

Common tests for measuring the threshold for shock initiation are the NOL large scale gap test (LSGT) with a 50.8-mm diameter donor/gap and the expanded large scale gap test (ELSGT) with a 95.3-mm diameter donor/gap. Despite the same specifications for the explosive donor and polymethyl methacrylate (PMMA) gap in both tests, calibration of shock pressure in the gap versus distance from the donor scales by a factor of 1.75, not the 1.875 difference in their sizes. Recently reported model calculations suggest that the scaling discrepancy results from the viscoelastic properties of PMMA in combination with different methods for obtaining shock pressure. This is supported by the consistent scaling of these donors when calibrated in water-filled aquariums. Calibrations and their scaling are compared for other donors with PMMA gaps and for various donors in water.

Sandusky, Harold

2012-03-01

334

Metabolic Syndrome and Migraine  

PubMed Central

Migraine and metabolic syndrome are highly prevalent and costly conditions. The two conditions coexist, but it is unclear what relationship may exist between the two processes. Metabolic syndrome involves a number of findings, including insulin resistance, systemic hypertension, obesity, a proinflammatory state, and a prothrombotic state. Only one study addresses migraine in metabolic syndrome, finding significant differences in the presentation of metabolic syndrome in migraineurs. However, controversy exists regarding the contribution of each individual risk factor to migraine pathogenesis and prevalence. It is unclear what treatment implications, if any, exist as a result of the concomitant diagnosis of migraine and metabolic syndrome. The cornerstone of migraine and metabolic syndrome treatments is prevention, relying heavily on diet modification, sleep hygiene, medication use, and exercise. PMID:23181051

Sachdev, Amit; Marmura, Michael J.

2012-01-01

335

[Menopause and metabolic syndrome].  

PubMed

The incidence of cardiovascular disease increases considerably after the menopause. One reason for the increased cardiovascular risk seems to be determined by metabolic syndrome, in which all components (visceral obesity, dyslipidemia, hypertension, and glucose metabolism disorder) are associated with higher incidence of coronary artery disease. After menopause, metabolic syndrome is more prevalent than in premenopausal women, and may plays an important role in the occurrence of myocardial infarction and other atherosclerotic and cardiovascular morbidities. Obesity, an essential component of the metabolic syndrome, is also associated with increased incidence of breast, endometrial, bowel, esophagus, and kidney cancer. The treatment of metabolic syndrome is based on the change in lifestyle and, when necessary, the use of medication directed to its components. In the presence of symptoms of the climacteric syndrome, hormonal therapy, when indicated, will also contribute to the improvement of the metabolic syndrome. PMID:24830585

Meirelles, Ricardo M R

2014-03-01

336

Selective anion exchange and tunable luminescent behaviors of metal-organic framework based supramolecular isomers.  

PubMed

Owing to the conformational (cis or trans) flexibility of a N-donor ligand, the combinations of the same and Cd(ClO4)2 under variable solvent templates afforded two supramolecular isomers based on two-dimensional metal-organic frameworks. Both compounds contain weakly coordinating ClO4(-) anions attached to the metal centers. Both frameworks showed facile anion exchange behaviors with various kinds of foreign anions. Moreover, both frameworks showed anion-driven structural dynamism and exhibited the preferential uptake of strongly coordinating anions over others. Anion-regulated modulation in luminescent behaviors was also observed in both cases. PMID:25492519

Manna, Biplab; Singh, Shweta; Karmakar, Avishek; Desai, Aamod V; Ghosh, Sujit K

2015-01-01

337

Tunable transport gap in phosphorene.  

PubMed

In this article, we experimentally demonstrate that the transport gap of phosphorene can be tuned monotonically from ?0.3 to ?1.0 eV when the flake thickness is scaled down from bulk to a single layer. As a consequence, the ON current, the OFF current, and the current ON/OFF ratios of phosphorene field effect transistors (FETs) were found to be significantly impacted by the layer thickness. The transport gap was determined from the transfer characteristics of phosphorene FETs using a robust technique that has not been reported before. The detailed mathematical model is also provided. By scaling the thickness of the gate oxide, we were also able to demonstrate enhanced ambipolar conduction in monolayer and few layer phosphorene FETs. The asymmetry of the electron and the hole current was found to be dependent on the layer thickness that can be explained by dynamic changes of the metal Fermi level with the energy band of phosphorene depending on the layer number. We also extracted the Schottky barrier heights for both the electron and the hole injection as a function of the layer thickness. Finally, we discuss the dependence of field effect hole mobility of phosphorene on temperature and carrier concentration. PMID:25111042

Das, Saptarshi; Zhang, Wei; Demarteau, Marcel; Hoffmann, Axel; Dubey, Madan; Roelofs, Andreas

2014-10-01

338

Cell Metabolism Perspective  

E-print Network

Cell Metabolism Perspective Mapping the Inner Workings of the Microbiome: Genomic-andMetagenomic-BasedStudyofMetabolism and Metabolic Interactions in the Human Microbiome Ohad Manor,1,4 Roie Levy,1,4 and Elhanan Borenstein1,2,3,* 1: elbo@uw.edu http://dx.doi.org/10.1016/j.cmet.2014.07.021 The human gut microbiome is a major

Borenstein, Elhanan

339

Overweight, Obesity, and Metabolic Syndrome in Adults and Children in South Korea: A Review of the Literature  

Microsoft Academic Search

Overweight, obesity, and metabolic syndrome are increasing in South Korea dramatically. This review of the literature summarizes published studies on the prevalence of overweight, obesity, and metabolic syndrome in South Korean adults and children; summarizes studies related to obesity management and prevention in South Korean adults and children; and identifies gaps in the literature for further research. A PubMed, CINAHL,

Myoungock Jang; Diane Berry

2011-01-01

340

Influences of anionic and cationic dopants on the morphology and optical properties of PbS nanostructures  

NASA Astrophysics Data System (ADS)

Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy (SEM) results show similar morphologies for the undoped and doped PbS nanostructures. X-ray diffraction (XRD) patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is demonstrated by X-ray photoelectron spectroscopy (XPS). Raman spectra of the synthesized samples confirm the XRD results and indicate five Raman active modes, which relate to the PbS cubic phase for all the nanostructures. Room temperature photoluminescence (PL) and UV—Vis spectrometers are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that emission and absorption peaks are in the infrared (IR) region of the electromagnetic spectrum for all PbS nanostructures. In addition, the optical studies of the doped PbS nanostructures reveal that the band gap of the Se-doped PbS is smaller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.

Ramin, Yousefi; Mohsen, Cheragizade; Farid, Jamali-Sheini; R. Mahmoudian, M.; Abdolhossein, Saaédi; Nay, Ming Huang

2014-10-01

341

Heterotypic gap junctions at glutamatergic mixed synapses are abundant in goldfish brain.  

PubMed

Gap junctions provide for direct intercellular electrical and metabolic coupling. The abundance of gap junctions at "large myelinated club ending (LMCE)" synapses on Mauthner cells (M-cells) of the teleost brain provided a convenient model to correlate anatomical and physiological properties of electrical synapses. There, presynaptic action potentials were found to evoke short-latency electrical "pre-potentials" immediately preceding their accompanying glutamate-induced depolarizations, making these the first unambiguously identified "mixed" (i.e., chemical plus electrical) synapses in the vertebrate CNS. We recently showed that gap junctions at these synapses exhibit asymmetric electrical resistance (i.e., electrical rectification), which we correlated with total molecular asymmetry of connexin composition in their apposing gap junction hemiplaques, with connexin35 (Cx35) restricted to axon terminal hemiplaques and connexin34.7 (Cx34.7) restricted to apposing M-cell plasma membranes. We now show that similarly heterotypic neuronal gap junctions are abundant throughout goldfish brain, with labeling exclusively for Cx35 in presynaptic hemiplaques and exclusively for Cx34.7 in postsynaptic hemiplaques. Moreover, the vast majority of these asymmetric gap junctions occur at glutamatergic axon terminals. The widespread distribution of heterotypic gap junctions at glutamatergic mixed synapses throughout goldfish brain and spinal cord implies that pre- vs. postsynaptic asymmetry at electrical synapses evolved early in the chordate lineage. We propose that the advantages of the molecular and functional asymmetry of connexins at electrical synapses that are so prominently expressed in the teleost CNS are unlikely to have been abandoned in higher vertebrates. However, to create asymmetric coupling in mammals, where most gap junctions are composed of connexin36 (Cx36) on both sides, would require some other mechanism, such as differential phosphorylation of connexins on opposite sides of the same gap junction or on asymmetric differences in the complement of their scaffolding and regulatory proteins. PMID:25451276

Rash, J E; Kamasawa, N; Vanderpool, K G; Yasumura, T; O'Brien, J; Nannapaneni, S; Pereda, A E; Nagy, J I

2015-01-29

342

Gaps in the GD-1 Star Stream  

NASA Astrophysics Data System (ADS)

GD-1 is a long, thin, Milky Way star stream that has readily visible density variations along its length. We quantify the locations, sizes, and statistical significance of the density structure, i.e., gaps, using a set of scaled filters. The shapes of the filters are based on the gaps that develop in simulations of dark matter sub-halos crossing a star stream. The high Galactic latitude 8.4 kpc long segment of GD-1 that we examine has 8 ± 3 gaps of 99% significance or greater, with the error estimated on the basis of tests of the gap-filtering technique. The cumulative distribution of gaps more than three times the width of the stream is in good agreement with predictions for dark matter sub-halo encounters with cold star streams. The number of gaps narrower than three times the width of the GD-1 stream falls well below the cold stream prediction which is taken into account for the gap creation rate integrated over all sizes. Simple warm stream simulations scaled to GD-1 show that the falloff in gaps is expected for sub-halos below a mass of 106 M ?. The GD-1 gaps requires 100 sub-halos >106 M ? within 30 kpc, the apocenter of GD-1 orbit. These results are consistent with LCDM sub-halo predictions but further improvements in stream signal-to-noise and gap modeling will be welcome.

Carlberg, R. G.; Grillmair, C. J.

2013-05-01

343

Anion Binding and Transport by Prodigiosin and Its Analogs  

NASA Astrophysics Data System (ADS)

The red-colored prodiginines, exemplified by prodigiosin 1, are secondary metabolites produced by a number of microorganisms, including the bacterium Serratia marcescens. These tripyrrole natural products and their synthetic analogs have received renewed attention over the past deacade, primarily because of their promising immunosuppressive and anticancer activities. One of the hallmarks of prodiginin chemistry is the ability of the monoprotonated ligand to bind anions, including the essential chloride and bicarbonate ions. The resulting lipophilic ion pair is then able to diffuse across the hydrophobic barrier presented by phospholipid bilayers. Thus, prodiginines have been found to be potent transmembrane anion transporters and HCl cotransporters. In this chapter, the author reviews what is known about the solid-state structure of prodiginins and their anion complexes, the solution conformation of prodiginines, and the biochemcal evidence for the ability to bind anions and to transport HCl across cell membranes. Recent progress in making synthetic models of prodiginines and recent results on the ability of prodigiosin to transport HCO 3 - across lipid membranes are discussed.

Davis, Jeffery T.

344

Size-regulable vesicles based on anion-? interactions.  

PubMed

Taking tetraoxacalix[2]arene[2]triazine as a functionalization platform, a series of new amphiphilic molecules were synthesized in 18 to 53?% yields by using a fragment coupling protocol. These amphiphilic molecules self-assembled into stable vesicles in a mixture of THF and water, with the surface of the vesicles engineered by electron-deficient cavities. Various anions are able to selectively influence the size of self-assembled vesicles, following the order of F(-) < ClO4(-) < SCN(-) < BF4(-) < Br(-) < Cl(-) < NO3(-), as revealed by DLS measurements. Such a sequence was independent with the hydration cost and in agreement with the binding strength of anions with tetraoxacalix[2]arene[2]triazine host molecule, indicating that the anion-? interaction most probably competed over other possible weak interactions and accounted for this interesting selectivity. In addition, the chloride permeation process across the membrane of the vesicles was also preliminarily studied by means of fluorescent experiments. This study, in addition to providing the potentiality of heteracalixaromatics as new models to construct functional vesicles, opens a new avenue to study the anion-? interactions in aqueous and also potentially in living systems. PMID:24824676

He, Qing; Han, Yuchun; Wang, Yilin; Huang, Zhi-Tang; Wang, De-Xian

2014-06-10

345

THE THERMODYNAMICS OF ANION EXCHANGE OF THE RARE EARTH ETHYLENEDIAMINETETRAACETATES  

Microsoft Academic Search

Distribution coefficients for the ion exchange reaction of the rare ; earth ethylenediaminetetraacetates in the system strongly basic anion exchange ; resin Amberlite IRA-400-aq. solution of di-Na-ethylenediaminetetraacetate were ; determined by column method with the use of radioactive tracers. From tuese ; data, partial molal free energy ( DELTA G\\/sup *\\/), enthalpy ( DELTA H\\/sup *\\/), ; entropy ( DELTA

Dybczynski

1963-01-01

346

The electronic structure of TEMPO, its cation and anion  

NASA Astrophysics Data System (ADS)

The electronic structure of TEMPO (2,2,6,6-tetramethyl-1-piperidinyl N-oxide), its cation and anion were studied experimentally using the following electron spectroscopy techniques: electron energy-loss spec-troscopy (EELS), measurement of elastic and vibrational excitation (VE) cross sections, HeI photoelectron (PE) spectroscopy and dissociative electron attachment (DEA) spectroscopy.

Regeta, Khrystyna; Jane?ková, Radmila; Kubala, Dušan; Fedor, Juraj; Allan, Michael

2014-04-01

347

Keggin anions promoted synthesis of zeolites and mesoporous materials  

Microsoft Academic Search

A rapid and convenient route to synthesize microporous (zeolites e.g. FAU, MFI and FER) and mesoporous (MCM-41 and MCM-48) materials employing Keggin anions as novel promoters has been reported. The catalytic use of these promoters not only reduces the syntheses time by 3 to 4 folds but also produces uniform and very small (nanosized) crystallites of the materials. Various Keggin

K. Mukhopadhyay; A. Ghosh; R. Kumar

2004-01-01

348

Transport and phase behavior in anion-conducting diblock copolymers  

NASA Astrophysics Data System (ADS)

Anion-exchange membranes can be used in various applications such as direct methanol fuel cells or devices for artificial photosynthesis. Consequently, these membranes have to conduct the anions efficiently, remain insoluble in water or methanol, and be impermeable to various gases. Block copolymers are good candidates to reach these aims. Their ability to self-assemble, particularly into bi-continuous phases, makes it possible to use one polycationic block that would conduct the anions, while a second neutral block can be designed as a structural block to insure the mechanical stability of the system. Our study focuses on the relationship between phase behavior and anion conductivity of diblock copolymers as a function of molecular weight, composition and cationic groups. We have chosen to use a model system made of styrene for the neutral block, and of chloromethylstyrene for the second block since it is easily cationizable with various functionalities, reacting easily with e.g. trimethylamine or n-butylimidazole. This model system is synthesized by nitroxide-mediated radical polymerization with molecular weights between 2 to 40 kg/mol and fractions of chloromethylstyrene in the range of 15-40 mol%. The results obtained from small-angle X-ray scattering showed lamellar morphologies for most systems. The temperature-dependence of the conductivity was assessed by performing measurements on membranes that were either immersed in water or in a controlled atmosphere at 98% of relative humidity.

Sudre, Guillaume; Inceoglu, Sebnem; Balsara, Nitash

2012-02-01

349

The Determination of Anionic Surfactants in Natural and Waste Waters.  

ERIC Educational Resources Information Center

Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

Crisp, P. T.; And Others

1983-01-01

350

Purification, characterization and catalytic activity of anionic zucchini peroxidase  

Microsoft Academic Search

The isolation and purification, by preparative electrofocusing, of the major anionic (ZPOA) and cationic (ZPOC) isoenzymes, collected from young zucchini squash, are reported. The Mr and sugar content are similar to those found previously for the major isoenzymes from the ripe fruits and in the range commonly observed for plant peroxidases. The amount of the two cationic enzymes was very

Luigi Casella; Michele Gullottit; Sonia Polit; Rosa Pia Ferrari; Enzo Laurenti; Augusto Marchesini

1993-01-01

351

Relationship Between Equilibrium Forms of Lysozyme Crystals and Precipitant Anions  

NASA Technical Reports Server (NTRS)

Molecular forces, such as electrostatic, hydrophobic, van der Waals and steric forces, are known to be important in determining protein interactions. These forces are affected by the solution conditions and changing the pH, temperature or the ionic strength of the solution can sharply affect protein interactions. Several investigations of protein crystallization have shown that this process is also strongly dependent on solution conditions. As the ionic strength of the solution is increased, the initially soluble protein may either crystallize or form an amorphous precipitate at high ionic strengths. Studies done on the model protein hen egg white lysozyme have shown that different crystal forms can be easily and reproducibly obtained, depending primarily on the anion used to desolubilize the protein. In this study we employ pyranine to probe the effect of various anions on the water structure. Additionally, lysozyme crystallization was carried out at these conditions and the crystal form was determined by X-ray crystallography. The goal of the study was to understand the physico-chemical basis for the effect of changing the anion concentration on the equilibrium form of lysozyme crystals. It will also verify the hypothesis that the anions, by altering the bulk water structure in the crystallizing solutions, alter the surface energy of the between the crystal faces and the solution and, consequently, the equilibrium form of the crystals.

Nadarajah, Arunan

1996-01-01

352

PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS  

EPA Science Inventory

Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

353

Stabilisation of titania pigment particles with anionic polymeric dispersants  

Microsoft Academic Search

The stabilisation of titania pigment in dry water-based paint films with anionic polymeric dispersants containing carboxylate groups was investigated. The results were compared to those obtained from rheological analysis of titania pigment suspensions. The polymeric dispersants chosen were polyacrylic acid and polyacrylamides copolymer modified with carboxylate groups. AFM and TEM were used to assess the distribution of the titania pigment

Saeed Farrokhpay; Gayle E. Morris; Daniel Fornasiero; Peter Self

2010-01-01

354

Attractor Metabolic Networks  

PubMed Central

Background The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core) while the rest of the catalytic processes are only intermittently active. This global metabolic structure was verified for Escherichia coli, Helicobacter pylori and Saccharomyces cerevisiae, and it seems to be a common key feature to all cellular organisms. In concordance with these observations, the cell can be considered a complex metabolic network which mainly integrates a large ensemble of self-organized multienzymatic complexes interconnected by substrate fluxes and regulatory signals, where multiple autonomous oscillatory and quasi-stationary catalytic patterns simultaneously emerge. The network adjusts the internal metabolic activities to the external change by means of flux plasticity and structural plasticity. Methodology/Principal Findings In order to research the systemic mechanisms involved in the regulation of the cellular enzymatic activity we have studied different catalytic activities of a dissipative metabolic network under different external stimuli. The emergent biochemical data have been analysed using statistical mechanic tools, studying some macroscopic properties such as the global information and the energy of the system. We have also obtained an equivalent Hopfield network using a Boltzmann machine. Our main result shows that the dissipative metabolic network can behave as an attractor metabolic network. Conclusions/Significance We have found that the systemic enzymatic activities are governed by attractors with capacity to store functional metabolic patterns which can be correctly recovered from specific input stimuli. The network attractors regulate the catalytic patterns, modify the efficiency in the connection between the multienzymatic complexes, and stably retain these modifications. Here for the first time, we have introduced the general concept of attractor metabolic network, in which this dynamic behavior is observed. PMID:23554883

De la Fuente, Ildefonso M.; Cortes, Jesus M.; Pelta, David A.; Veguillas, Juan

2013-01-01

355

Continuous layer gap plasmon resonators.  

PubMed

We demonstrate both theoretically and experimentally that a gold nanostrip supported by a thin dielectric (silicon dioxide) film and a gold underlay forms an efficient (Fabry-Perot) resonator for gap surface plasmons. Periodic nanostrip arrays are shown to exhibit strong and narrow resonances with nearly complete absorption and quality factors of ~15-20 in the near-infrared. Two-photon luminescence microscopy measurements reveal intensity enhancement factors of ~120 in the 400-nm-period array of 85-nm-wide gold strips atop a 23-nm-thick silica film at the resonance wavelength of ~770 nm. Excellent resonant characteristics, the simplicity of tuning the resonance wavelength by adjusting the nanostrip width and/or the dielectric film thickness and the ease of fabrication with (only) one lithography step required make the considered plasmonic configuration very attractive for a wide variety of applications, ranging from surface sensing to photovoltaics. PMID:21996871

Nielsen, Michael G; Gramotnev, Dmitri K; Pors, Anders; Albrektsen, Ole; Bozhevolnyi, Sergey I

2011-09-26

356

Activation of Estrogen Receptor-? by the Anion Nitrite  

PubMed Central

In this study, the ability of nitrite and nitrate to mimic the effects of estradiol on growth and gene expression was measured in the human breast cancer cell line MCF-7. Similar to estradiol, treatment of MCF-7 cells with either 1 ?mol/L nitrite or 1 ?mol/L nitrate resulted in ~4-fold increase in cell growth and 2.3-fold to 3-fold increase in progesterone receptor (PgR), pS2, and cathepsin D mRNAs that were blocked by the antiestrogen ICI 182,780. The anions also recruited estrogen receptor-? (ER?) to the pS2 promoter and activated exogenously expressed ER? when tested in transient cotransfection assays. To determine whether nitrite or nitrate was the active anion, diphenyleneiodonium was used to inhibit oxidation/reduction reactions in the cell. The ability of diphenyleneiodonium to block the effects of nitrate, but not nitrite, on the induction of PgR mRNA and the activation of exogenously expressed ER? suggests that nitrite is the active anion. Concentrations of nitrite, as low as 100 nmol/L, induced a significant increase in PgR mRNA, suggesting that physiologically and environmentally relevant doses of the anion activate ER?. Nitrite activated the chimeric receptor Gal-ER containing the DNA-binding domain of GAL-4 and the ligand-binding domain of ER? and blocked the binding of estradiol to the receptor, suggesting that the anion activates ER? through the ligand-binding domain. Mutational analysis identified the amino acids Cys381, His516, Lys520, Lys529, Asn532, and His547 as important for nitrite activation of the receptor. PMID:18483281

Veselik, David J.; Divekar, Shailaja; Dakshanamurthy, Sivanesan; Storchan, Geoffrey B.; Turner, Jasmine M.A.; Graham, Kelly L.; Huang, Li; Stoica, Adriana; Martin, Mary Beth

2013-01-01

357

Narrow gap electronegative capacitive discharges  

SciTech Connect

Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)] [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

2013-10-15

358

Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas.  

PubMed

Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate. PMID:25178589

Karagiannidis, Louise E; Haynes, Cally J E; Holder, Katie J; Kirby, Isabelle L; Moore, Stephen J; Wells, Neil J; Gale, Philip A

2014-10-18

359

Lithium Diisopropylamide-Mediated Ortholithiation and Anionic Fries Rearrangement of Aryl Carbamates: Role of  

E-print Network

Lithium Diisopropylamide-Mediated Ortholithiation and Anionic Fries Rearrangement of Aryl of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates are described, an LDA-lithium phenolate mixed dimer, and homoaggregated lithium phenolates. The highly insoluble

Collum, David B.

360

Effects of Hofmeister anions on the aggregation behavior of PEO-PPO-PEO triblock copolymers.  

PubMed

The effects of a series of Hofmeister anions on the phase behaviors of a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer were investigated with an automated melting point system. Well hydrated anions and poorly hydrated anions interacted with the polymer differently and further affected the phase transition of the polymer. Poorly hydrated anions worked through changing the interfacial tension at the polymer/aqueous interface and in enhancing the polymer hydration by ion binding. The phase transition of the polymer in the presence of well hydrated anions correlated directly to the hydration entropy of the anions. As a consequence, the polymer showed a two-step phase transition in solutions containing poorly hydrated anions while displayed a single-step phase transition in the presence of well hydrated anions. The mechanisms of how ions interact with the polymer and further modulate its phase behaviors were discussed. PMID:21688819

Deyerle, Branden A; Zhang, Yanjie

2011-08-01

361

ION CHROMATOGRAPHIC DETERMINATION OF SOLUBLE ANIONS PRESENT IN COAL FLY ASH LEACHATES (JOURNAL VERSION)  

EPA Science Inventory

The advent of ion chromatography has provided an extremely useful tool for the rapid, precise and sensitive determination of inorganic anions. This capability can be put to excellent use in the determination of soluble anions associated with coal fly ash....

362

National GAP Conference 2007-Discussion Groups Report  

USGS Publications Warehouse

We led two discussion groups during the 2007 National GAP Conference. These discussion groups provided information to help develop a survey of National Gap Analysis Program (GAP) data users. One group discussed technical issues, and the second group discussed the use of GAP data for decisionmaking. Themes emerging from the technical issues group included concerns about data quality, need for information on how to use data, and passive data distribution. The decisionmaking discussion included a wide range of topics including the need to understand presentation of information, the need to connect with and understand users of data, the revision of GAP's mission, and the adaptability of products and data. The decisionmaking group also raised concerns regarding technical issues. One conclusion is that a deep commitment to ongoing information transfer and support is a key component of success for the GAP program.

Ratz, Joan M.; Lamb, Berton Lee

2010-01-01

363

Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving  

PubMed Central

Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts. PMID:24138155

Martín-Tereso, J; ter Wijlen, H; van Laar, H; Verstegen, M W A

2014-01-01

364

Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving.  

PubMed

Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts. PMID:24138155

Martín-Tereso, J; ter Wijlen, H; van Laar, H; Verstegen, M W A

2014-08-01

365

The metabolic syndrome  

Microsoft Academic Search

This constellation of metabolic disturbances, all risk factors for cardiovascular disease, was first described in the 1920s by Kylin, a Swedish physician, as the clustering of hypertension, hyperglycaemia, and gout. 2 Later, in 1947, Vague drew attention to upper body adiposity (android or male-type obesity) as the obesity phenotype that was commonly associated with metabolic abnormalities associated with type 2

Robert H Eckel; Scott M Grundy; Paul Z Zimmet

2005-01-01

366

Oncogenic alterations of metabolism  

Microsoft Academic Search

Over seven decades ago, classical biochemical studies showed that tumors have altered metabolic profiles and display high rates of glucose uptake and glycolysis. Although these metabolic changes are not the fundamental defects that cause cancer, they might confer a common advantage on many different types of cancers, which allows the cells to survive and invade. Recent molecular studies have revealed

Chi V. Dang; Gregg L. Semenza

1999-01-01

367

METABOLIC PATHWAY REGULATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Research efforts in the past two decades have revealed the complex mechanisms employed by fungi to control gene activity. The tremendous expansion in our knowledge of the regulation of nitrogen metabolism and carbon metabolism, due largely to the powerful combination of genetics, biochemistry, and ...

368

METABOLISM OF CARBAMATE INSECTICIDES  

EPA Science Inventory

The results of studies conducted to determine the metabolic fate of carbamate insecticides and its toxicological significance are presented. Methomyl metabolism in rats was investigated in detail as was Croneton in the rat, cow, pig and chicken. Carbaryl and carbofuran were admin...

369

Metabolic bone disease  

Microsoft Academic Search

Metabolic bone dlseases are frequently seen in the geriatric population. The pain which often accompanies the disorder is\\u000a a major cause of morbidity, frequent visits to the physician, health resource utilization, and even mortality. Successful\\u000a prevention, detection and management of metabolic bone disease are essential components of optimal geriatric health care.

Jeffrey E. Escher; Steven Gambert; Bruce Rothschild

1987-01-01

370

Metabolic bone disease  

Microsoft Academic Search

Metabolic bone disease results from a complex variety of causes but can generally be divided into conditions that mainly cause osteoporosis and those that result principally in osteomalacia. Some conditions show a mixture of these two states. Investigation of metabolic bone disease should follow a logical progression and a diagnosis can usually be made if this sequence is adhered to.

Jeremy Allgrove

2007-01-01

371

Metabolic bone disease  

Microsoft Academic Search

Metabolic bone disease is most often diagnosed by a combination of radiological features, clinical signs and symptoms and biochemistry for serum calcium, phosphate and alkaline phosphatase. The most common metabolic bone disease is osteoporosis which affects elderly patients, particularly women and is a disease on the increase in the Western world. It is now recognized that osteoporosis can be of

A. J. Malcolm

2002-01-01

372

The pGAPS experiment: An engineering balloon flight of prototype GAPS  

NASA Astrophysics Data System (ADS)

The General Anti-Particle Spectrometer (GAPS) project is being carried out to search for primary cosmic-ray antiparticles especially for antideuterons produced by cold dark matter. GAPS plans to realize the science observation by Antarctic long duration balloon flights in the late 2010s. In preparation for the Antarctic science flights, an engineering balloon flight using a prototype of the GAPS instrument, "pGAPS", was successfully carried out in June 2012 in Japan to verify the basic performance of each GAPS subsystem. The outline of the pGAPS flight campaign is briefly reported.

Fuke, H.; Ong, R. A.; Aramaki, T.; Bando, N.; Boggs, S. E.; Doetinchem, P. v.; Gahbauer, F. H.; Hailey, C. J.; Koglin, J. E.; Madden, N.; Mognet, S. A. I.; Mori, K.; Okazaki, S.; Perez, K. M.; Yoshida, T.; Zweerink, J.

2014-05-01

373

Thiamin function, metabolism, uptake, and transport.  

PubMed

Vitamins are crucial components in the diet of animals and many other living organisms. One of these essential nutrients, thiamin, is known to be involved in several cell functions, including energy metabolism and the degradation of sugars and carbon skeletons. Other roles that are connected to this vitamin are neuronal communication, immune system activation, signaling and maintenance processes in cells and tissues, and cell-membrane dynamics. Because of the key functions of thiamin, uptake and transport through the body are crucial. Its uptake route is relatively complex, encompassing a variety of protein families, including the solute carrier anion transporters, the alkaline phosphatase transport system, and the human extraneuronal monoamine transporter family, some of which are multispecific proteins. There are two known structures of protein (subunits) involved in thiamin uptake in prokaryotes. Binding of thiamin to these proteins is strongly guided by electrostatic interactions. The lack of structural information about thiamin binding proteins for higher organisms remains a bottleneck for understanding the uptake process of thiamin in atomic detail. This review includes recent data on thiamin metabolism, related deficiencies and pathologies, and the latest findings on thiamin binding transporters. PMID:24460461

Manzetti, Sergio; Zhang, Jin; van der Spoel, David

2014-02-11

374

Chiral gap effect in curved space  

E-print Network

We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

Antonino Flachi; Kenji Fukushima

2014-06-25

375

Gap between active and passive solar heating  

SciTech Connect

The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

Balcomb, J.D.

1985-01-01

376

On the Psychology of Truth-Gaps  

NASA Astrophysics Data System (ADS)

Bonini et al. [2] present psychological data that they take to support an 'epistemic' account of how vague predicates are used in natural language. We argue that their data more strongly supports a 'gap' theory of vagueness, and that their arguments against gap theories are flawed. Additionally, we present more experimental evidence that supports gap theories, and argue for a semantic/pragmatic alternative that unifies super- and subvaluationary approaches to vagueness.

Alxatib, Sam; Pelletier, Jeff

377

Four-wave-mixing gap solitons  

SciTech Connect

We report an experimental demonstration of generating gap soliton trains in a four-wave-mixing (FWM) signal. Such spatial FWM surfacelike gap soliton trains are induced in a periodically modulated self-defocusing atomic medium by the cross-phase modulation, which can be reshaped under different experimental conditions, such as different atomic densities, nonlinear dispersions, and dressing fields. Controlling spatial gap solitons can have important applications in image memory, processing, and communication.

Zhang Yanpeng; Wang Zhiguo; Zheng Huaibin; Yuan Chenzhi; Li Changbiao; Lu Keqing [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, Xi'an Jiaotong University, Xi'an 710049 (China); Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

2010-11-15

378

Multiple anion binding by a zinc-containing tetratopic cyclen-resorcinarene  

Microsoft Academic Search

The synthesis and binding properties of a new tetratopic anion receptor are reported. The resorcinarene ligand bearing four\\u000a cyclen moieties is able to bind four Zn2+ ions and subsequently bind anions. NMR titrations show proton shifts during the binding of the first one or two anions. Isothermal\\u000a titration calorimetry (ITC) titrations show that two or more anions bind to one

Jing Wang; John D. Lamb; Lee D. Hansen; Roger G. Harrison

2010-01-01

379

DIABETES, OBESITY AND METABOLISM INSTITUTE  

E-print Network

DIABETES, OBESITY AND METABOLISM INSTITUTE AT NORTHWESTERN MEDICINE THE INSTITUTES AT NORTHWESTERN MEDICINE #12;THE INSTITUTES AT NORTHWESTERN MEDICINE DIABETES, OBESITY AND METABOLISM INSTITUTE AT NORTHWESTERN MEDICINE "As we launch the Diabetes, Obesity and Metabolism Institute at Northwestern Medicine, I

Engman, David M.

380

Large-gap magnetic suspension systems  

NASA Technical Reports Server (NTRS)

The classification of magnetic suspension devices into small-gap and large-gap categories is addressed. The relative problems of position sensing, control systems, power supplies, electromagnets, and magnetic field or force analysis are discussed. The similarity of all systems from a controls standpoint is qualified. Some applications where large-gap technology is being applied to systems with a physically small air-gap are mentioned. Finally, the applicability of some other suspension approaches, such as electrodynamic or superconducting are briefly addressed.

Britcher, Colin P.

1992-01-01

381

Valence Anions in Complexes of Adenine and 9-Methyladenine with Formic Acid: Stabilization by  

E-print Network

. The neutral and anionic complexes of adenine/9-methyladenine and formic acid were also studied computationally yield versus incident electron energy suggests that the resonance anions of nucleic acid bases (NBs) mayValence Anions in Complexes of Adenine and 9-Methyladenine with Formic Acid: Stabilization

Simons, Jack

382

Gap Junction Proteins in the Blood-Brain Barrier Control Nutrient-Dependent Reactivation of Drosophila Neural Stem Cells  

PubMed Central

Summary Neural stem cells in the adult brain exist primarily in a quiescent state but are reactivated in response to changing physiological conditions. How do stem cells sense and respond to metabolic changes? In the Drosophila CNS, quiescent neural stem cells are reactivated synchronously in response to a nutritional stimulus. Feeding triggers insulin production by blood-brain barrier glial cells, activating the insulin/insulin-like growth factor pathway in underlying neural stem cells and stimulating their growth and proliferation. Here we show that gap junctions in the blood-brain barrier glia mediate the influence of metabolic changes on stem cell behavior, enabling glia to respond to nutritional signals and reactivate quiescent stem cells. We propose that gap junctions in the blood-brain barrier are required to translate metabolic signals into synchronized calcium pulses and insulin secretion. PMID:25065772

Spéder, Pauline; Brand, Andrea H.

2014-01-01

383

Emission channeling studies on transition-metal doped GaN and ZnO: Cation versus anion substitution  

NASA Astrophysics Data System (ADS)

The magnetic and electric properties of impurities in semiconductors are strongly dependent on the lattice sites which they occupy. While the majority site can often be predicted based on chemical similarities with the host elements and is usually simple to confirm experimentally, minority sites are far more complicated to predict, detect and identify. We have carried out extensive ?- emission channeling studies on the lattice location of transition metal impurities in wide-gap dilute magnetic semiconductors, namely Co and Mn in GaN and ZnO, making use of radioactive 61Co and 56Mn implanted at the ISOLDE facility at CERN. In addition to the majority occupation of cation (Ga, Zn) sites, we located significant fractions (of the order of 20%) of the Co and Mn impurities in anion (N, O) sites, which are virtually unaffected by thermal annealing up to 900 °C. Here, we present the ?- emission channeling experiments on 61Co-implanted GaN. We discuss these results in the context of our recent reports of minority anion substitution in Mn-implanted GaN Pereira et al. (2012) [19] and Mn/Co-implanted ZnO Pereira et al. (2011) [20], particularly in terms of the advantages of the emission channeling technique in such cases of multi-site occupancy.

Pereira, L. M. C.; Wahl, U.; Correia, J. G.; Amorim, L. M.; Silva, D. J.; Decoster, S.; da Silva, M. R.; Temst, K.; Vantomme, A.

2014-08-01

384

Gap Assessment (FY 13 Update)  

SciTech Connect

To help guide its future data collection efforts, The DOE GTO funded a data gap analysis in FY2012 to identify high potential hydrothermal areas where critical data are needed. This analysis was updated in FY2013 and the resulting datasets are represented by this metadata. The original process was published in FY 2012 and is available here: https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2013/Esposito.pdf Though there are many types of data that can be used for hydrothermal exploration, five types of exploration data were targeted for this analysis. These data types were selected for their regional reconnaissance potential, and include many of the primary exploration techniques currently used by the geothermal industry. The data types include: 1. well data 2. geologic maps 3. fault maps 4. geochemistry data 5. geophysical data To determine data coverage, metadata for exploration data (including data type, data status, and coverage information) were collected and catalogued from nodes on the National Geothermal Data System (NGDS). It is the intention of this analysis that the data be updated from this source in a semi-automated fashion as new datasets are added to the NGDS nodes. In addition to this upload, an online tool was developed to allow all geothermal data providers to access this assessment and to directly add metadata themselves and view the results of the analysis via maps of data coverage in Geothermal Prospector (http://maps.nrel.gov/gt_prospector). A grid of the contiguous U.S. was created with 88,000 10-km by 10-km grid cells, and each cell was populated with the status of data availability corresponding to the five data types. Using these five data coverage maps and the USGS Resource Potential Map, sites were identified for future data collection efforts. These sites signify both that the USGS has indicated high favorability of occurrence of geothermal resources and that data gaps exist. The uploaded data are contained in two data files for each data category. The first file contains the grid and is in the SHP file format (shape file.) Each populated grid cell represents a 10k area within which data is known to exist. The second file is a CSV (comma separated value) file that contains all of the individual layers that intersected with the grid. This CSV can be joined with the map to retrieve a list of datasets that are available at any given site. The attributes in the CSV include: 1. grid_id : The id of the grid cell that the data intersects with 2. title: This represents the name of the WFS service that intersected with this grid cell 3. abstract: This represents the description of the WFS service that intersected with this grid cell 4. gap_type: This represents the category of data availability that these data fall within. As the current processing is pulling data from NGDS, this category universally represents data that are available in the NGDS and are ready for acquisition for analytic purposes. 5. proprietary_type: Whether the data are considered proprietary 6. service_type: The type of service 7. base_url: The service URL

Getman, Dan

2013-09-30

385

Direct band gap wurtzite GaP nanowires for LEDs and quantum devices  

NASA Astrophysics Data System (ADS)

Commercially available light-emitting diodes (LEDs) suffer from low-efficiency in the green region of the visible spectrum. In order to solve this issue III-V materials such as Gallium phosphide (GaP) can be investigated. GaP in the zinc blende (ZB) crystal structure has an indirect band gap, limiting the efficiency of the green emission. However, when the material is grown with wurtzite (WZ) crystal phase a direct band gap is predicted. Here, we show the fabrication and the characterization of wurtzite GaP nanowires, together with the demonstration of the direct band gap. The strong photoluminescence signal observed at 594 nm with a lifetime in the order of 1ns matches with the expectation for a direct band gap material. Furthermore, the emission wavelength can be tuned across a wide range of the visible spectrum (555-690 nm) by incorporating aluminum or arsenic in the WZ GaP nanowires.

Assali, S.; Kriegner, D.; Zardo, I.; Plissard, S.; Verheijen, M. A.; Stangl, J.; Haverkort, J. E. M.; Bakkers, E. P. A. M.

2014-09-01

386

A "light-on" colorimetric assay for anion detection using the inhibitory effect of anions on the catalytic activity of metal nanoparticles for the degradation of methyl orange.  

PubMed

In this communication, we studied the inhibitory effects of anions on the catalytic activity of metal nanoparticles for the degradation of methyl orange (MO). Some anions have great affinity with specific metal nanoparticles, thus resulting in the change of surface state and inhibition of catalytic activity, which can be observed with the naked eye or manifested in the UV spectrum of MO for anion detection. PMID:25317955

Lu, Lixia; Yang, Fan; Yang, Xiurong

2014-12-01

387

Testing metabolic theories.  

PubMed

Metabolism is the process by which individual organisms acquire energy and materials from their environment and use them for maintenance, differentiation, growth, and reproduction. There has been a recent push to build an individual-based metabolic underpinning into ecological theory-that is, a metabolic theory of ecology. However, the two main theories of individual metabolism that have been applied in ecology-Kooijman's dynamic energy budget (DEB) theory and the West, Brown, and Enquist (WBE) theory-have fundamentally different assumptions. Surprisingly, the core assumptions of these two theories have not been rigorously compared from an empirical perspective. Before we can build an understanding of ecology on the basis of individual metabolism, we must resolve the differences between these theories and thus set the appropriate foundation. Here we compare the DEB and WBE theories in detail as applied to ontogenetic growth and metabolic scaling, from which we identify circumstances where their predictions diverge most strongly. Promising experimental areas include manipulative studies of tissue regeneration, body shape, body condition, temperature, and oxygen. Much empirical work designed specifically with DEB and WBE theory in mind is required before any consensus can be reached on the appropriate theoretical basis for a metabolic theory of ecology. PMID:23070317

Kearney, Michael R; White, Craig R

2012-11-01

388

Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.  

PubMed

A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV). PMID:24884171

Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

2014-06-01

389

Differential distribution of synGAP?1 and synGAP? isoforms in rat neurons  

Microsoft Academic Search

The synaptic Ras-GTPase activating protein synGAP is a brain-specific protein of approximately 130 kDa and is a negative regulator of Ras. We previously reported 5 C-terminal isoforms of synGAP (?1, ?2, ?1\\/2, ?3\\/4 and ?) [Li et al., 2001, J. Biol. Chem. 276: 21417–21424]. In this study, we investigated the expression profiles of the two major isoforms, synGAP?1 and synGAP?, in

Il Soo Moon; Hiroyuki Sakagami; Jun Nakayama; Tatsuo Suzuki

2008-01-01

390

Personality and metabolic syndrome  

PubMed Central

The prevalence of metabolic syndrome has paralleled the sharp increase in obesity. Given its tremendous physical, emotional, and financial burden, it is of critical importance to identify who is most at risk and the potential points of intervention. Psychological traits, in addition to physiological and social risk factors, may contribute to metabolic syndrome. The objective of the present research is to test whether personality traits are associated with metabolic syndrome in a large community sample. Participants (N?=?5,662) from Sardinia, Italy, completed a comprehensive personality questionnaire, the NEO-PI-R, and were assessed on all components of metabolic syndrome (waist circumference, triglycerides, high-density lipoprotein cholesterol, blood pressure, and fasting glucose). Logistic regressions were used to predict metabolic syndrome from personality traits, controlling for age, sex, education, and current smoking status. Among adults over age 45 (n?=?2,419), Neuroticism and low Agreeableness were associated with metabolic syndrome, whereas high Conscientiousness was protective. Individuals who scored in the top 10% on Conscientiousness were approximately 40% less likely to have metabolic syndrome (OR?=?0.61, 95% CI?=?0.41–0.92), whereas those who scored in the lowest 10% on Agreeableness were 50% more likely to have it (OR?=?1.53, 95% CI?=?1.09–2.16). At the facet level, traits related to impulsivity and hostility were the most strongly associated with metabolic syndrome. The present research indicates that those with fewer psychological resources are more vulnerable to metabolic syndrome and suggests a psychological component to other established risk factors. PMID:20567927

Costa, Paul T.; Uda, Manuela; Ferrucci, Luigi; Schlessinger, David; Terracciano, Antonio

2010-01-01

391

Novel fragmentation pathways of anionic adducts of steroids formed by electrospray anion attachment involving regioselective attachment, regiospecific decompositions, charge-induced pathways, and ion-dipole complex intermediates.  

PubMed

The analysis of several bifunctional neutral steroids, 5-?-pregnane diol (5-?-pregnane-3?-20?diol), estradiol (3,17?-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3?-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3?-ol-20-one), and pregnenolone acetate (5-pregnen-3?-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion](-) adducts of these steroids revealed that fluoride adduct [M + F](-) precursors first lose HF to produce [M - H](-) and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d(4)-pregnenolone, are also discussed. PMID:22733166

Rannulu, Nalaka S; Cole, Richard B

2012-09-01

392

Novel Fragmentation Pathways of Anionic Adducts of Steroids Formed by Electrospray Anion Attachment Involving Regioselective Attachment, Regiospecific Decompositions, Charge-Induced Pathways, and Ion-Dipole Complex Intermediates  

NASA Astrophysics Data System (ADS)

The analysis of several bifunctional neutral steroids, 5-?-pregnane diol (5-?-pregnane-3?-20?diol), estradiol (3,17?-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3?-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3?-ol-20-one), and pregnenolone acetate (5-pregnen-3?-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion]- adducts of these steroids revealed that fluoride adduct [M + F]- precursors first lose HF to produce [M - H]- and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d4-pregnenolone, are also discussed.

Rannulu, Nalaka S.; Cole, Richard B.

2012-09-01

393

Gap junction proteins and their role in spinal cord injury  

PubMed Central

Gap junctions are specialized intercellular communication channels that are formed by two hexameric connexin hemichannels, one provided by each of the two adjacent cells. Gap junctions and hemichannels play an important role in regulating cellular metabolism, signaling, and functions in both normal and pathological conditions. Following spinal cord injury (SCI), there is damage and disturbance to the neuronal elements of the spinal cord including severing of axon tracts and rapid cell death. The initial mechanical disruption is followed by multiple secondary cascades that cause further tissue loss and dysfunction. Recent studies have implicated connexin proteins as playing a critical role in the secondary phase of SCI by propagating death signals through extensive glial networks. In this review, we bring together past and current studies to outline the distribution, changes and roles of various connexins found in neurons and glial cells, before and in response to SCI. We discuss the contribution of pathologically activated connexin proteins, in particular connexin 43, to functional recovery and neuropathic pain, as well as providing an update on potential connexin specific pharmacological agents to treat SCI. PMID:25610368

Tonkin, Ryan S.; Mao, Yilin; O’Carroll, Simon J.; Nicholson, Louise F. B.; Green, Colin R.; Gorrie, Catherine A.; Moalem-Taylor, Gila

2015-01-01

394

Anion inhibition studies of two ?-carbonic anhydrases from Lotus japonicus, LjCAA1 and LjCAA2.  

PubMed

The model organism for the investigation of symbiotic nitrogen fixation in legumes Lotus japonicus encodes two carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the ?-class, LjCAA1 and LjCAA2. Here we report the kinetic characterization and inhibition of these two CAs with inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, and phenylboronic/arsonic acids. LjCAA1 showed a high catalytic activity for the CO2 hydration reaction, with a k(cat) of 7.4?10(5) s(-1) and a k(cat)/K(m) of 9.6?10(7) M(-1) s(-1) and was inhibited in the low micromolar range by N,N-diethyldithiocarbamate, sulfamide, sulfamic acid, phenylboronic/arsonic acid (K(I)s of 4-62 ?M). LjCAA2 showed a moderate catalytic activity for the physiologic reaction, with a k(cat) of 4.0?10(5) s(-1) and a k(cat)/K(m) of 4.9?10(7) M(-1) s(-1). The same anions mentioned above for the inhibition of LjCAA1 showed the best activity against LjCAA2 (K(I)s of 7-29 ?M). Nitrate and nitrite, anions involved in nitrogen fixation, showed lower affinity for the two enzymes, with inhibition constants in the range of 3.7-7.0 mM. Halides and sulfate also behaved in a distinct manner towards the two enzymes investigated here. As LjCAA1/2 participate in the pH regulation processes and CO2 metabolism within the nitrogen-fixing nodules of the plant, our studies may shed some light regarding these complex biochemical processes. PMID:24769135

Vullo, Daniela; Flemetakis, Emmanouil; Scozzafava, Andrea; Capasso, Clemente; Supuran, Claudiu T

2014-07-01

395

Physiology of Iron Metabolism  

PubMed Central

Summary A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. ‘Ironomics’ certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism. PMID:25053935

Waldvogel-Abramowski, Sophie; Waeber, Gérard; Gassner, Christoph; Buser, Andreas; Frey, Beat M.; Favrat, Bernard; Tissot, Jean-Daniel

2014-01-01

396

A computerized metabolic map.  

PubMed

We have developed a computer representation of metabolic pathways that incorporates metabolic reactive spaces, species distinctions, and reversibility considerations. Furthermore, the distinction is made between pathway substrates and cosubstrates. Reactions are represented as entries in a database; the code was developed under dBASE III+. Two views onto the database have been developed: a spanning tree which performs a depth search and a stepwise navigational approach which offers reaction possibilities one at a time. In addition, metabolic pathways of any desired starting point are output as a Warnier diagram. PMID:2026661

Ochs, R S; Conrow, K

1991-02-01

397

Closing the Gender Gap: Act Now  

ERIC Educational Resources Information Center

Gender gaps are pervasive in all walks of economic life and imply large losses in terms of foregone productivity and living standards to the individuals concerned and the economy. This new OECD report focuses on how best to close these gender gaps under four broad headings: (1) Gender equality, social norms and public policies; and gender equality…

OECD Publishing (NJ3), 2012

2012-01-01

398

Ignalina NPP RBMK-1500 gas gap evaluation  

Microsoft Academic Search

This paper presents Ignalina NPP Unit 1 RBMK-1500 reactor core lifetime analysis. The closure of the gas gap between the pressure tubes and the graphite bricks is one of the criteria for the evaluation of the reactor core lifetime. The rate of closure of the approximately 1.5 mm gaps between the pressure tubes and the graphite is largely a function

J Augutis; E Uspuras; M Liaukonis

2001-01-01

399

Reusable Thermal Barrier for Insulation Gaps  

NASA Technical Reports Server (NTRS)

Filler composed of resilient, heat-resistant materials. Thermal barrier nestles snugly in gap between two tiles with minimal protrusion beyond faces of surrounding tiles. When removed from gap, barrier springs back to nearly original shape. Developed for filling spaces between tiles on Space Shuttle, also used in furnaces and kilns.

Saladee, C. E.

1985-01-01

400

The Classroom Dynamics of Information Gap Activities.  

ERIC Educational Resources Information Center

Discusses the term "information gap," which suggests that the primary reason for communication is that each person possesses knowledge that is unknown to others. The article summarizes theories behind peer interaction in language learning and describes the construction of Information Gap Activities (IGA) in the foreign-language classroom from…

Walz, Joel

1996-01-01

401

Photonic band gaps in dusty plasma crystals  

Microsoft Academic Search

A two-dimensional model for electromagnetic wave propagation in a dusty plasma crystal is solved using plane wave expansion techniques. We show that photonic band gaps, where propagation is forbidden, can occur for a range of Debye length scale sizes with respect to the dust particle size. We find that band gap features are dependent on the plasma sheath characteristics of

M. J. Keskinen; R. Fernsler

2000-01-01

402

Closing the Achievement Gap: Challenges and Opportunities  

ERIC Educational Resources Information Center

Closing the achievement gap between low- and high-achieving public school students is an important goal of public education. This article explores background information and research and discusses examples of best practices to close the achievement gap. Several plans have been proposed as ways to enhance the achievement of under-represented…

Robards, Shirley N.

2008-01-01

403

Magnetic properties of new Haldane gap materials  

NASA Astrophysics Data System (ADS)

High-field magnetization and susceptibility measurements have been performed on the linear-chain Heisenberg antiferromagnets Ni(dmpn) 2N 3(CIO 4) and catena-(?-N 3)?Ni(323-tet)](CIO 4). These compounds have an energy gap at low temperatures, and the values of energy gap, crystalline field constants are estimated from the high-field magnetization data.

Takeuchi, T.; Yosida, T.; Inoue, K.; Yamashita, M.; Kumada, T.; Kindo, K.; Merah, S.; Verdaguer, M.; Renard, J. P.

1995-02-01

404

Plasmonic band gap cavities on biharmonic gratings  

Microsoft Academic Search

In this paper, we have experimentally demonstrated the formation of plasmonic band gap cavities in infrared and visible wavelength range. The cavity structure is based on a biharmonic metallic grating with selective high dielectric loading. A uniform metallic grating structure enables strong surface plasmon polariton (SPP) excitation and a superimposed second harmonic component forms a band gap for the propagating

Askin Kocabas; S. Seckin Senlik; Atilla Aydinli

2008-01-01

405

Subgroup Achievement and Gap Trends: Idaho, 2010  

ERIC Educational Resources Information Center

This paper profiles the student subgroup achievement and gap trends in Idaho for 2010. Idaho showed improvement in reading and math in grade 8 at the basic, proficient, and advanced levels for Latino and white students, low income students, and boys and girls. The state has also made progress in narrowing achievement gaps between Latino and white…

Center on Education Policy, 2010

2010-01-01

406

Gas mixtures for spark gap closing switches  

DOEpatents

Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

Christophorou, L.G.; McCorkle, D.L.; Hunter, S.R.

1987-02-20

407

GAP-43 Gene Expression Regulates Information Storage  

ERIC Educational Resources Information Center

Previous reports have shown that overexpression of the growth- and plasticity-associated protein GAP-43 improves memory. However, the relation between the levels of this protein to memory enhancement remains unknown. Here, we studied this issue in transgenic mice (G-Phos) overexpressing native, chick GAP-43. These G-Phos mice could be divided at…

Holahan, Matthew R.; Honegger, Kyle S.; Tabatadze, Nino; Routtenberg, Aryeh

2007-01-01

408

The "Developing" Achievement Gap: Colombian Voucher Reform  

ERIC Educational Resources Information Center

The achievement gap in many developing countries is defined in terms of rich/poor and public/private. The prevailing explanation for the "developing" achievement gap is an underfunded, inefficient, and/or inadequately supplied public school sector. Via an analysis of a Colombian voucher experiment, this article examines the extent to…

Stern, Jonathan M. B.

2014-01-01

409

Is the Gender Gap in Unemployment Disappearing?  

NSF Publications Database

Is The Gender Gap In Unemployment Disappearing? This Issue Brief contrasts trends in the gender gap in unemployment among doctoral scientists and engineers with trends in the larger labor force and examines the question of whether marriage and children have different effects on unemployment among men and women. See Help for more information about viewing publications in different formats.

410

Energy gap in the aetiology of body weight gain and obesity: a challenging concept with a complex evaluation and pitfalls.  

PubMed

The concept of energy gap(s) is useful for understanding the consequence of a small daily, weekly, or monthly positive energy balance and the inconspicuous shift in weight gain ultimately leading to overweight and obesity. Energy gap is a dynamic concept: an initial positive energy gap incurred via an increase in energy intake (or a decrease in physical activity) is not constant, may fade out with time if the initial conditions are maintained, and depends on the 'efficiency' with which the readjustment of the energy imbalance gap occurs with time. The metabolic response to an energy imbalance gap and the magnitude of the energy gap(s) can be estimated by at least two methods, i.e. i) assessment by longitudinal overfeeding studies, imposing (by design) an initial positive energy imbalance gap; ii) retrospective assessment based on epidemiological surveys, whereby the accumulated endogenous energy storage per unit of time is calculated from the change in body weight and body composition. In order to illustrate the difficulty of accurately assessing an energy gap we have used, as an illustrative example, a recent epidemiological study which tracked changes in total energy intake (estimated by gross food availability) and body weight over 3 decades in the US, combined with total energy expenditure prediction from body weight using doubly labelled water data. At the population level, the study attempted to assess the cause of the energy gap purported to be entirely due to increased food intake. Based on an estimate of change in energy intake judged to be more reliable (i.e. in the same study population) and together with calculations of simple energetic indices, our analysis suggests that conclusions about the fundamental causes of obesity development in a population (excess intake vs. low physical activity or both) is clouded by a high level of uncertainty. PMID:24457473

Schutz, Yves; Byrne, Nuala M; Dulloo, Abdul; Hills, Andrew P

2014-01-01

411

Uranyl nitrate-exposed rat alveolar macrophages cell death: influence of superoxide anion and TNF ? mediators.  

PubMed

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5-200 ?M). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO? 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO?. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O??). At high doses it provokes the secretion of TNF? and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O?? may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O?? may be blocked, prevailing damage to DNA by the TNF? route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium-related diseases. PMID:22561334

Orona, N S; Tasat, D R

2012-06-15

412

Studies on the role of insect hemolymph polypeptides: Galleria mellonella anionic peptide 2 and lysozyme.  

PubMed

The lysozymes are well known antimicrobial polypeptides exhibiting antibacterial and antifungal activities. Their antibacterial potential is related to muramidase activity and non-enzymatic activity resembling the mode of action of cationic defense peptides. However, the mechanisms responsible for fungistatic and/or fungicidal activity of lysozyme are still not clear. In the present study, the anti-Candida albicans activity of Galleria mellonella lysozyme and anionic peptide 2 (AP2), defense factors constitutively present in the hemolymph, was examined. The lysozyme inhibited C. albicans growth in a dose-dependent manner. The decrease in the C. albicans survival rate caused by the lysozyme was accompanied by a considerable reduction of the fungus metabolic activity, as revealed by LIVE/DEAD staining. In contrast, although AP2 reduced C. albicans metabolic activity, it did not influence its survival rate. Our results suggest fungicidal action of G. mellonella lysozyme and fungistatic activity of AP2 toward C. albicans cells. In the presence of AP2, the anti-C. albicans activity of G. mellonella lysozyme increased. Moreover, when the fungus was incubated with both defense factors, true hyphae were observed besides pseudohyphae and yeast-like C. albicans cells. Atomic force microscopy analysis of the cells exposed to the lysozyme and/or AP2 revealed alterations in the cell surface topography and properties in comparison with the control cells. The results indicate synergistic action of G. mellonella AP2 and lysozyme toward C. albicans. The presence of both factors in the hemolymph of naive larvae suggests their important role in the early stages of immune response against fungi in G. mellonella. PMID:24472857

Sowa-Jasi?ek, Aneta; Zdybicka-Barabas, Agnieszka; St?czek, Sylwia; Wydrych, Jerzy; Mak, Pawe?; Jakubowicz, Teresa; Cytry?ska, Ma?gorzata

2014-03-01

413

Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth  

NASA Astrophysics Data System (ADS)

We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

2010-12-01

414

Self-assembly of silicotungstate anions on silver surfaces  

SciTech Connect

We report here the self assembly of {alpha}-dodecatungstosilicate anions, {alpha}-SiW{sub 12}O{sub 40}{sup 4-}, on Ag(111) surfaces from acidic aqueous solution. The ability of {alpha}-SiW{sub 12}O{sub 40}{sup 4-} to form self-assembled monolayers on Ag(111) offers great opportunity for generalization to other functionalized inorganic molecules on other surfaces. We find that the silicotungstate anions will also adhere to Cu surfaces, and we anticipate that they will bind to other oxophilic surfaces (e.g., Al, W, Ni) once the oxide layer is removed. Polyoxometalates function as superacids, ion exchangers, corrosion inhibitors, electron transfer reagents, catalysts, and photochemical oxidants. Since they can accommodate a wide range of organic, organometallic, and inorganic functional groups, we anticipate widespread exploration of these and other classes of inorganic molecules as self-assembled monolayers. 22 refs., 2 figs.

Ge, M.; Zhong, B.; Klemperer, W.G.; Gewirth, A.A. [Univ. of Illinois, Urbana, IL (United States)] [Univ. of Illinois, Urbana, IL (United States)

1996-06-19

415

Alanate anion, AlH4(-): photoelectron spectrum and computations.  

PubMed

The alanate anion, AlH4(-), was generated in the gas phase using a pulsed arc cluster ionization source. Its photoelectron spectrum was then measured with 193 nm photons. The spectrum consists of a broad feature, spanning electron binding energies from 3.8 eV to over 5.3 eV. This band reflects the photodetachment transitions between the ground state of the AlH4(-) anion and the ground state of its thermodynamically unstable neutral counterpart, AlH4. The vertical detachment energy (VDE) of AlH4(-) was measured to be 4.4 eV. Additionally, VDE values were also computed in a comprehensive theoretical study and compared both with the previously computed value and with our experimentally determined value. PMID:24512169

Graham, J D; Buytendyk, A M; Zhang, X; Collins, E L; Kiran, B; Gantefoer, G; Eichhorn, B W; Gutsev, G L; Behera, S; Jena, P; Bowen, K H

2014-09-18

416

Dissolution of cellulose in room temperature ionic liquids: anion dependence.  

PubMed

The dissolution of cellulosic biomass in room temperature ionic liquids (RTILs) is studied through free energy calculations of its monomer, viz., cellobiose, within a molecular dynamics simulation approach. The solvation free energy (SFE) of cellobiose in ionic liquids containing any of seven different anions has been calculated. The ranking of these liquids based on SFE compares well with experimental data on the solubility of cellulose. The dissolution is shown to be enthalpically dominated, which is correlated with the strength of intermolecular hydrogen bonding between cellobiose and the anions of the IL. Large entropic changes upon solvation in [CF3SO3](-) and [OAc](-) based ionic liquids have been explained in terms of the solvent-aided conformational flexibility of cellobiose. PMID:25535797

Payal, Rajdeep Singh; Bejagam, Karteek K; Mondal, Anirban; Balasubramanian, Sundaram

2015-01-29

417

Bias free gap creation in bilayer graphene.  

PubMed

For graphene to be utilized in the digital electronics industry the challenge is to create bandgaps of order 1 eV as simply as possible. The most successful methods for the creation of gaps in graphene are (a) confining the electrons in nanoribbons, which is technically difficult or (b) placing a potential difference across bilayer graphene, which is limited to gaps of around 300 meV for reasonably sized electric fields. Here we propose that electronic band gaps can be created without applying an external electric field, by using the electron-phonon interaction formed when bilayer graphene is sandwiched between highly polarisable ionic materials. We derive and solve self-consistent equations, finding that a large gap can be formed for intermediate electron-phonon coupling. The gap originates from the amplification of an intrinsic Coulomb interaction due to the proximity of carbon atoms in neighbouring planes. PMID:24824315

Davenport, A R; Hague, J P

2014-06-01

418

Narrow band gap amorphous silicon semiconductors  

DOEpatents

Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

Madan, A.; Mahan, A.H.

1985-01-10

419

Anion receptor compounds for non-aqueous electrolytes  

SciTech Connect

A new family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

2000-09-19

420

Collisional electron transfer to photoexcited acceptor radical anions  

NASA Astrophysics Data System (ADS)

In this article, we show that photoexcitation of radical anions facilitates electron transfer from sodium atoms in femtosecond encounters. Thus, excitation of 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) and fluorinated TCNQ (TCNQ-F4) anions to the second optically active state at 478 nm led to increases in the yields of dianions of about 20% and 10%, respectively. Photoexcitation with a nanosecond-long laser pulse was done a few microseconds before the ions entered the sodium collision cell so that none of the ions would be in any of the initially reached doublet-excited states. We suggest an explanation for the higher electron capture cross section based on the formation of long-lived quartet state anions. Excitation of TCNQ anions within the lowest-energy absorption band, where there are no accessible quartet states, led instead to a lower yield of dianions. There are at least three explanations for the lower dianion yields: (1) Depletion of the monoanion beam due to photodetachment after the absorption of minimum two photons; (2) Formation of short-lived vibrationally excited dianions that decay by electron autodetachment prior to identification; and (3) Lower electron capture cross sections of vibrationally excited monoanions. Similar losses in dianion signal can occur at 478 nm so the actual yield of dianions at this wavelength due to the population of quartet states is therefore greater than that observed. Our methodology devises a more efficient route for the production of molecular dianions, and at the same time it may provide information on long-lived electronic states.

Wyer, Jean Ann; Støchkel, Kristian; Nielsen, Steen Brøndsted

2012-02-01

421

Dynamics of Hydration of Alkylsulfonate Anions in Aqueous Solutions  

Microsoft Academic Search

The 17O-NMR spin-lattice relaxation times (T\\u000a 1) of water molecules in aqueous solutions of n-alkylsulfonate (C1 to C6) and arylsulfonic anions were determined as a function of concentration at 298 K. Values of the dynamic hydration number,\\u000a , were determined from the concentration dependence of T\\u000a 1. The ratios () of the rotational correlation times () of the water molecules around

Shoichi Okouchi; Pariya Thanatuksorn; Shiego Ikeda; Hisashi Uedaira

2011-01-01

422

Direct and mediated electron transfer catalyzed by anionic tobacco peroxidase  

Microsoft Academic Search

The properties of anionic tobacco peroxidase (TOP) adsorbed on graphite electrode have been studied in direct and mediated\\u000a electron transfer in a wall-jet flow injection system. The percentage of tobacco peroxidase molecules active in directelectron\\u000a transfer is about 83%, which is higher than that for horeradish peroxidase (40–50%). This observation is explained in terms\\u000a of the lower degree of glycosylation

Florentina-Daniela Munteanu; Lo Gorton; Annika Lindgren; Tautgirdas Ruzgas; Jenny Emnéus; Elisabeth Csöregi; Irina G. Gazaryan; Igor V. Ouporov; Elena A. Mareeva; L. Mark Lagrimini

2000-01-01

423

Interactions between anionic and neutral bromine and rare gas atoms  

SciTech Connect

High-quality, ab initio potential energy functions are obtained for the interaction of bromine atoms and anions with atoms of the six rare gases (Rg) from He to Rn. The potentials of the nonrelativistic {sup 2}{sigma}{sup +} and {sup 2}{pi} electronic states arising from the ground-state Br({sup 2}P)-Rg interactions are computed over a wide range of internuclear separations using a spin-restricted version of the coupled cluster method with single and double excitations and noniterative correction to triple excitations [RCCSD(T)] with an extrapolation to the complete basis set limit, from basis sets of d-aug-cc-pVQZ and d-aug-cc-pV5Z quality. These are compared with potentials derived previously from experimental measurements and ab initio calculations. The same approach is used also to refine the potentials of the Br{sup -}-Rg anions obtained previously [Buchachenko et al., J. Chem. Phys. 125, 064305 (2006)]. Spin-orbit coupling in the neutral species is included both ab initio and via an atomic approximation; deviations between two approaches that are large enough to affect the results significantly are observed only in the Br-Xe and Br-Rn systems. The resulting relativistic potentials are used to compute anion zero electron kinetic energy photoelectron spectra, differential scattering cross sections, and the transport coefficients of trace amounts of both anionic and neutral bromine in the rare gases. Comparison with available experimental data for all systems considered proves a very high precision of the present potentials.

Buchachenko, Alexei A.; Grinev, Timur A.; Wright, Timothy G.; Viehland, Larry A. [Department of Chemistry, Moscow State University, Moscow 119991 (Russian Federation); School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Division of Science, Chatham University, Pittsburgh, Pennsylvania 15232 (United States)

2008-02-14

424

Cation and anion contributions to gustatory quality of simple salts  

Microsoft Academic Search

Curves of mean percentages of the four gustatory quality responses as a function of concentration of solutions of LiCl, KCl,\\u000a lithium sulfate, and potassium sulfate were evaluated as to the relative contributions of the cation and anion to the quality.\\u000a It was concluded that chloride ion, and sulfate ion to a lesser degree, were responsible for the salty quality. In

Ernest Dzendolet; Herbert L. Meiselman

1967-01-01

425

Intermolecular proton transfer in anionic complexes of uracil with alcohols  

Microsoft Academic Search

A series of eighteen alcohols (ROH) has been designed with an enthalpy of deprotonation (HDP) in a range of 13.8-16.3 eV. The effects of excess electron attachment to the binary alcohol-uracil (ROHâ¦U) complexes have been studied at the density functional level with a B3LYP exchange-correlation functional and at the second order Møller-Plesset perturbation theory level. The photoelectron spectra of anionic

Maciej Haranczyk; Janusz Rak; Maciej S. Gutowski; Dunja Radisic; Sarah T. Stokes; Kit H. Bowen

2005-01-01

426

Partial charge transfer during anion adsorption. Methodological aspects  

NASA Astrophysics Data System (ADS)

Some problems of applying the Lippmann equation to ionic adsorption on solid electrodes are considered. The possibility of using a nonthermodynamic approach to certain thermodynamic problems (particularly, the role of elastic and plastic deformations of electrode surfaces in adsorption processes, the polarity of surface bonds during anion adsorption, and others) is discussed. The extremely thin electrode layer affected electrically and mechanically by adsorbate is considered to be free of dislocations because of volume discrepancy. The nearest structure-mechanical analogs of such layers are whiskers'-type crystals whose side surface could have point-, one- and two-dimensional defects, but not dislocations. Like whiskers, surface metal layers ought to possess an ultimate strength close to theoretical one (0.2 E) and a purely elastic deformation up to 0.04. The surface electrode layer (affected by adsorbate only) should be considered as an absolutely elastic body, whose plastic deformation is impossible. It means that the simple Lippmann equation and other equations containing terms of plastic deformation cannot be used in thermodynamics of the solid metal surface. Coefficients of the partial charge transfer and electrosorption valence of anions, as well as the role of electron tunneling in the formation of the contact electric resistance (CER) signal are considered. The relation between the charge transfer during adsorption of anions and the surface reconstruction of monocrystalline electrodes is analyzed. The beginning of the substantial charge transfer is proposed to be a trigger of the surface reconstruction process. The nature and adsorption of solvent molecules are shown to play a decisive role in the charge transfer during anion adsorption. The results are compared to the available literature data.

Marichev, V. A.

2005-03-01

427

Layered double hydroxides as anion- and cation-exchanging materials  

Microsoft Academic Search

Layered double hydroxides (LDH) have been principally known as anion-exchanging, clay-like materials for several decades, and continues to be the main driving force for current and future research. The chemical interactions of LDH, with transition metallocyanides, have been a popular topic of investigation for many years, partly due to the use of powder x-ray diffraction and infrared spectroscopy as the

Mickey Charles Richardson

2007-01-01

428

Bicarbonate permeability of the outwardly rectifying anion channel.  

PubMed

Single anion-selective channels have been studied in cultured human epithelial cells using the patch-clamp technique. Three cell types were used as models for different anion transport systems: (i) PANC-1, a cell line derived from the pancreatic duct, (ii) T84, a Cl-secreting colonic cell line, and (iii) primary cultures of sweat duct epithelium. Outwardly rectifying anion-selective channels were observed in all three preparations and were indistinguishable with respect to conductance, selectivity and gating. Striking similarities between HCO3- and Cl-secreting epithelia, and the high density of outward rectifiers in pancreatic cells prompted us to study HCO3 permeation through this channel. HCO3 permeability was significant when channels were bathed in symmetrical 150 mM HCO3 solutions, Cl-HCO3 mixtures, and under bi-ionic conditions with outwardly and inwardly directed HCO3 gradients. Permeability ratios (PHCO3/PCl) estimated from bi-ionic reversal potentials ranged from 0.50 to 0.64, although conductance ratios greater than 1.2 were observed with high extracellular pH. Chloride did not inhibit HCO3 permeation noticeably but rather had a small stimulatory effect when present on the opposite side of the membrane. The prevalence of outward rectifiers in PANC-1 and their permeability to bicarbonate suggests the channel may have a dual role in HCO3 secretion; to allow Cl recycling at the apical membrane and to mediate some of the HCO3 flux. Defective modulation of this channel in cystic fibrosis might provide a common basis for dysfunction in epithelia having very different anion transport properties (e.g., HCO3 secretion, Cl secretion and Cl absorption. PMID:2482894

Tabcharani, J A; Jensen, T J; Riordan, J R; Hanrahan, J W

1989-12-01

429

Ceramic membrane ultrafiltration of anionic and nonionic surfactant solutions  

Microsoft Academic Search

The ultrafiltration of two types of surfactants, sodium dodecyl sulfate (SDS, anionic) and Tergitol NP-9 (nonylphenol polyethylene glycol ether, nonionic), using a 20nm ZrO2 tubular membrane was investigated. The influence of crossflow velocity, temperature, pressure, and surfactant concentration on the permeate flux, close to and above the critical micelle concentration (CMC), is reported. Permeate flux and surfactant retention were measured

Eva Fernández; José Manuel Benito; Carmen Pazos; José Coca

2005-01-01

430

Gap Analysis - A Geographic Approach to Planning for Biological Diversity  

USGS Publications Warehouse

The 2008 issue of the Gap Analysis Bulletin is the sixteenth in a series of annual publications produced by the Gap Analysis Program. Gap Analysis Bulletin No. 16 features 16 articles on various aspects of gap analysis methods and results. Topics addressed include applications, land cover, and aquatic gap analysis. The Bulletin also includes a section on the current status of each GAP regional project. This issue also contains summaries for completed GAP state projects.

Maxwell, Jill, (Edited By); Gergely, Kevin; Aycrigg, Jocelyn; Davidson, Anne

2009-01-01

431

Phosphate Removal by Anion Binding on Functionalized Nanoporous Sorbents  

PubMed Central

Phosphate was captured from aqueous solutions by cationic metal-EDA complexes anchored inside mesoporous silica MCM-41 supports (Cu(II)-EDA-SAMMS and Fe(III)-EDA-SAMMS). Fe-EDA-SAMMS was more effective at capturing phosphate than the Cu-EDA-SAMMS and was further studied for matrix effects (e.g., pH, ionic strength, and competing anions) and sorption performance (e.g., capacity and rate). The adsorption of phosphate was highly pH dependent; it increased with increasing pH from 1.0 to 6.5, and decreased above pH 6.5. The adsorption was affected by high ionic strength (0.1 M of NaCl). In the presence of 1000-fold molar excess of chloride and nitrate anions, phosphate removal by Fe-EDA-SAMMS was not affected. Slight, moderate and large impacts were seen with bicarbonate, sulfate and citrate anions, respectively. The phosphate adsorption data on Fe-EDA-SAMMS agreed well with the Langmuir model with the estimated maximum capacity of 43.3 mg/g. The material displayed rapid sorption rate (99% of phosphate removal within 1 min) and lowering the phosphate content to ~ 10 µg/L of phosphorus, which is lower than the EPA’s established freshwater contaminant level for phosphorous (20 µg/L). PMID:20345133

Chouyyok, Wilaiwan; Wiacek, Robert J.; Pattamakomsan, Kanda; Sangvanich, Thanapon; Grudzien, Rafal M.; Fryxell, Glen E.; Yantasee, Wassana

2010-01-01

432

Determination of selected anions in water by ion chromatography  

USGS Publications Warehouse

Ion chromatography is a rapid, sensitive, precise, and accurate method for the determination of major anions in rainwater and surface waters. Simultaneous analyses of a single sample for bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate require approximately 20 minutes to obtain a chromatogram. Minimum detection limits range from 0.01 mg/L for fluoride to 0.20 mg/L for chloride and sulfate. Relative standard deviations were less than 9% for all anions except nitrite in Standard Reference Water Samples. Only one reference sample contained nitrite and its concentration was near the minimum level of detection. Similar precision was found for chloride, nitrate, and sulfate at concentrations less than 5 mg/L in rainfall samples. Precision for fluoride ranged from 12 to 22%, but is attributed to the low concentrations in these samples. The other anions were not detected. To determine accuracy of results, several samples were spiked with known concentrations of fluoride, chloride, nitrate, and sulfate; recoveries ranged from 96 to 103%. Known amounts of bromide and phosphate were added, separately, to several other waters, which contained bromide or phosphate. Recovery of added bromide and phosphate ranged from approximately 95 to 104%. No recovery data were obtained for nitrite. Chloride, nitrate, nitrite, orthophosphate, and sulfate, in several samples, were also determined independently by automated colorimetric procedures. An automated ion-selective electrode method was used to determine fluoride. Results are in agreement with results obtained by ion chromatography. (USGS).

Fishman, Marvin J.; Pyen, Grace

1979-01-01

433

Solubility and transport of cationic and anionic patterned nanoparticles  

NASA Astrophysics Data System (ADS)

We analyze bulk diffusion and transport through hydrophobic nanochannels of nanoparticles (NPs) with different hydrophobic-hydrophilic patterns achieved by coating a fraction of the NP sites with positive or negative charges via explicit solvent molecular dynamics simulations. Ten different charge pattern types including Janus charged-hydrophobic NPs are studied. The cationic NPs are more affected by the patterns and have higher diffusion constants and fluxes than their anionic NPs counterparts. The NP-water interaction dependence on surface pattern and field strength explains these observations. The NP-water Coulomb interaction of anionic NPs in the bulk, which are much stronger than the hydrophobic NP-water interactions, are stronger for NPs with higher localized charge, and stronger than in the cationic NPs counterparts. The diffusion and transport of anionic NPs such as proteins and protein charge ladders with the same total charge but different surface charge patterns are slowest for the highest localized charge pattern, which also adsorb strongest onto surfaces. Our model demonstrates the separation (by reverse osmosis, capillary electrophoresis, or chromatography) of cationic NPs, including proteins with equal net charge but different surface charge distributions.

Su, Jiaye; Olvera de La Cruz, Monica; Guo, Hongxia

2012-01-01

434

Lithium cation conducting TDI anion-based ionic liquids.  

PubMed

In this paper we present the synthesis route and electrochemical properties of new class of ionic liquids (ILs) obtained from lithium derivate TDI (4,5-dicyano-2-(trifluoromethyl)imidazolium) anion. ILs synthesized by us were EMImTDI, PMImTDI and BMImTDI, i.e. TDI anion with 1-alkyl-3-methylimidazolium cations, where alkyl meant ethyl, propyl and butyl groups. TDI anion contains fewer fluorine atoms than LiPF6 and thanks to C-F instead of P-F bond, they are less prone to emit fluorine or hydrogen fluoride due to the rise in temperature. Use of IL results in non-flammability, which is making such electrolyte even safer for both application and environment. The thermal stability of synthesized compounds was tested by DSC and TGA and no signal of decomposition was observed up to 250 °C. The LiTDI salt was added to ILs to form complete electrolytes. The structures of tailored ILs with lithium salt were confirmed by X-ray diffraction patterns. The electrolytes showed excellent properties regarding their ionic conductivity (over 3 mS cm(-1) at room temperature after lithium salt addition), lithium cation transference number (over 0.1), low viscosity and broad electrochemical stability window. The ionic conductivity and viscosity measurements of pure ILs are reported for reference. PMID:24803282

Niedzicki, Leszek; Karpierz, Ewelina; Zawadzki, Maciej; Dranka, Maciej; Kasprzyk, Marta; Zalewska, Aldona; Marcinek, Marek; Zachara, Janusz; Doma?ska, Urszula; Wieczorek, W?adys?aw

2014-06-21

435

Theoretical study of interactions between electron-deficient arenes and coinage metal anions.  

PubMed

The binding behavior of coinage metal anions with some electron-deficient arenes has been investigated by MP2 calculations, and the character of interactions in these complexes has been examined by NBO analysis. The results indicate that coinage metal anions can interact with electron-deficient arenes to form anion-?, strong ?-type and hydrogen-bonding complexes. The ?-type structure is the global minimum for triazine, trifluorotriazine, hexafluorobenzene and tricyanobenzene, and the hydrogen-bonding structure is the global minimum for trifluorobenzene. There exist some differences in the stability of anion-? complexes for coinage metal anions: the anion-? complexes of Au(-) are minima expect for triazine complex; the anion-? complexes of Ag(-) are minima expect for tricyanobenzene complex; and the anion-? complexes of Cu(-) are not minima expect for trifluorobenzene complex. The binding strength of anion-? and hydrogen-bonding complexes for Au(-) is larger than that for Ag(-) and Cu(-), but the binding strength of ? complex displays a different sequence: Cu(-) > Au(-) > Ag(-). The binding behavior of coinage metal anions is more similar to that of F(-) than that of Cl(-) and Br(-). The relaxed potential energy surface scans for some selected systems have been performed to help understand the interactions between coinage metal anions with electron-deficient arenes. PMID:25663520

Chen, Yishan; Wang, Fan

2015-03-01

436

Metabolism. Part III: Lipids.  

ERIC Educational Resources Information Center

Describes the metabolic processes of complex lipids, including saponification, activation and transport, and the beta-oxidation spiral. Discusses fatty acid degradation in regard to biochemical energy and ketone bodies. (TW)

Bodner, George M.

1986-01-01

437

Metabolism in cancer patients.  

PubMed

Today still only 50% of newly diagnosed cancers can be cured. While molecular mechanisms of cell proliferation are being studied intensively, comparably little research energy, however, has been spent on unravelling metabolic interactions of cancer and host tissues. Evidence is accumulating that systemic as well as local metabolic patterns have considerable impact on tumour growth, as well as on body composition and organ functions. This may lead to new treatments in oncology. Cancer development - and recurrence - may be inhibited by physical activity, as well as by avoiding obesity, the metabolic syndrome and insulin resistance. Antineoplastic treatments induce reductions in nutritional intake and require individually tailored nutritional support. New concepts are being considered to metabolically starve or reprogram cancer cells. During palliative treatment of progressive tumours, it should be good clinical practice to avoid or treat malnutrition and chronic inflammatory states. At late stages, the primary goal should be symptomatic relief and attention to subjective individual needs. PMID:20592393

Arends, Jann

2010-05-01

438

Metabolic Bone Diseases  

Microsoft Academic Search

\\u000a The current chapter provides an overview of the important imaging features observed in metabolic bone diseases [1, 2]. Common and uncommon imaging findings observed in insufficiency stress fractures are reviewed and illustrated.

BrunoVande Berg; Frederic Lecouvet; Paolo Simoni; Jacques Malghem

439

BMP (Basic Metabolic Panel)  

MedlinePLUS

... Pages On This Site Apart from the Related Tests noted above, there are no other related pages on this site. Elsewhere On The Web MedlinePlus Medical Encyclopedia: Basic metabolic panel » See all ...

440

Determination of the dissolved anion composition of ancient lakes from fossil ostracodes.  

USGS Publications Warehouse

The mineralogy of evaporite and other precipitated minerals has provided traditional sources of information about the major dissolved ion composition of ancient lakes. The paleocompositional resolving power of these methods is generally greatest in high-salinity lakes. Ostracodes live in dilute saline lakes where a species occurrence is determined by the relative proportions of the lake's major dissolved anions, so that each species describes specific areas on an anion trilinear diagram. The upper salinity tolerance of each species depends upon the types of major anions in solution and is therefore anion-specific. Knowledge about both anion and anion-salinity tolerances of an ostracode may ultimately provide a means of estimating absolute anion concentrations in paleolakes. Because ostracodes are common fossils in lake sediments, they provide an important new source of original paleocompositional information suitable for many geologic, climatic, geochemical, and paleontologic studies. -from Author

Forester, R.M.

1986-01-01

441

Process for separating and recovering an anionic dye from an aqueous solution  

DOEpatents

A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution.

Rogers, Robin (DeKalb, IL); Horwitz, E. Philip (Naperville, IL); Bond, Andrew H. (Tallahassee, FL)

1998-01-01

442

Voltage-dependant anion channels: Novel insights into isoform function through genetic models?  

PubMed Central

Voltage-dependant Anion Channels, also known as mitochondrial porins, are pore-forming proteins located in the mitochondrial outer membrane (MOM) that, in addition to forming complexes with other proteins that localize to the MOM, also function as the main conduit for transporting metabolites between the cytoplasm and mitochondria. VDACs are encoded by a multi-member gene family, and the number of isoforms and specific functions of VDACs varies between species. Translating the well-described in vitro characteristics of the VDAC isoforms into in vivo functions has been a challenge, with the generation of animal models of VDAC deficiency providing much of the available information about isoform-specific roles in biology. Here, we review the approaches used to create these insect and mammalian animal models, and the conclusions reached by studying the consequences of loss of function mutations on the genetic, physiologic, and biochemical properties of the resulting models. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism. PMID:22051019

Raghavan, Adithya; Sheiko, Tatiana; Graham, Brett H.; Craigen, William J.

2014-01-01

443

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN.  

PubMed

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions (O2?-) in mitochondria, either by chemical inhibition of complex I or by genetic silencing of O2?--dismutating mitochondrial Sod2. The O2?--dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of ?1(I), ?1(III), and ?2(I) collagen, the hallmarks of skin ageing. Enhanced O2?- led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated O2?--induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with O2?-, PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

2014-01-01

444

The Arabidopsis voltage-dependent anion channel 2 is required for plant growth  

PubMed Central

The voltage-dependent anion channels (VDACs), known as a major group of outer mitochondrial membrane proteins, are present in all eukaryotic species. In mammalian cells, they have been established as a key player in mitochondrial metabolism and apoptosis regulation. By contrast, little is known about the function of plant VDACs. Recently, we performed functional analysis of all VDAC gene members in Arabidopsis thaliana, and revealed that each AtVDAC member has a specialized function. Especially, in spite of similar subcellular localization and expression profiling of AtVDAC2 and AtVDAC4, both the T-DNA insertion knockout mutants of them, vdac2–2 and vdac4–2, showed severe growth retardation. These results suggest that AtVDAC2 and AtVDAC4 proteins clearly have distinct functions. Here, we introduced the AtVDAC2 gene into the vdac2–2 mutant, and demonstrated that the miniature phenotype of vdac2–2 plant is abolished by AtVDAC2 expression. PMID:22301963

Tateda, Chika; Kusano, Tomonobu; Takahashi, Yoshihiro

2012-01-01

445

N-glycosylation Dictates Proper Processing of Organic Anion Transporting Polypeptide 1B1  

PubMed Central

Organic anion transporting polypeptides (OATPs) have been extensively recognized as key determinants of absorption, distribution, metabolism and excretion (ADME) of various drugs, xenobiotics and toxins. Putative N-glycosylation sites located in the extracellular loops 2 and 5 is considered a common feature of all OATPs and some members have been demonstrated to be glycosylated proteins. However, experimental evidence is still lacking on how such a post-translational modification affect the transport activity of OATPs and which of the putative glycosylation sites are utilized in these transporter proteins. In the present study, we substituted asparagine residues that are possibly involved in N-glycosylation with glutamine residues and identified three glycosylation sites (Asn134, Asn503 and Asn516) within the structure of OATP1B1, an OATP member that is mainly expressed in the human liver. Our results showed that Asn134 and Asn516 are used for glycosylation under normal conditions; however, when Asn134 was mutagenized, an additional asparagine at position 503 is involved in the glycosylation process. Simultaneously replacement of all three asparagines with glutamines led to significantly reduced protein level as well as loss of transport activity. Further studies revealed that glycosylation affected stability of the transporter protein and the unglycosylated mutant was retained within endoplasmic reticulum. PMID:23285087

Huang, Jiujiu; Zhan, Kai; Huang, Hong; Hong, Mei

2012-01-01

446

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN  

PubMed Central

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions () in mitochondria, either by chemical inhibition of complex I or by genetic silencing of -dismutating mitochondrial Sod2. The -dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of ?1(I), ?1(III), and ?2(I) collagen, the hallmarks of skin ageing. Enhanced led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated -induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with , PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

2015-01-01

447

Metabolic Bone Disease  

Microsoft Academic Search

\\u000a Metabolic bone disease may result from genetic, endocrine, nutritional, or biochemical disorders, with variable and often\\u000a inconsistent imaging findings. For the radiologist, the cornerstone of “metabolic bone disease” has been osteoporosis, osteomalacia,\\u000a hyperparathyroidism, and Paget’s disease. Over the past three decades, the diagnosis and therapy of these diseases has changed,\\u000a influenced by biochemical discoveries, imaging advances, and epidemiology studies that

Murali Sundaram

448

Abdominal obesity and metabolic syndrome  

Microsoft Academic Search

Metabolic syndrome is associated with abdominal obesity, blood lipid disorders, inflammation, insulin resistance or full-blown diabetes, and increased risk of developing cardiovascular disease. Proposed criteria for identifying patients with metabolic syndrome have contributed greatly to preventive medicine, but the value of metabolic syndrome as a scientific concept remains controversial. The presence of metabolic syndrome alone cannot predict global cardiovascular disease

Jean-Pierre Després; Isabelle Lemieux

2006-01-01

449

Molecular Structures and Energetics of the (ZrO?)n and (HfO?)n (n = 1-4) Clusters and Their Anions  

SciTech Connect

The group IVB transition-metal dioxide clusters and their anions, (MO?)n and (MO?)n? (M = Zr, Hf; n = 1-4), are studied with coupled cluster (CCSD(T)) theory and density functional theory (DFT). Similar to the results for M = Ti, these oxide clusters have a number of low-lying isomeric structures, which can make it difficult to predict the ground electronic state especially for the anion. Electron affinities for the low-lying structures are calculated and compared with those for M = Ti. Electron affinities of these clusters depend strongly on the cluster structures. Anion photoelectron spectra are calculated for the monomer and dimer and demonstrate the possibility for structural identification at a spectral line width of ?0.05 eV. Electron excitation energies from the low-lying states to the singlet and triplet excited states are calculated self-consistently, as well as by the time-dependent DFT and equation-of-motion coupled cluster (EOM-CCSD) methods. The calculated excitation energies are compared to the band energies of bulk oxides, indicating that the excitation energy is not yet converged for n = 4 for these clusters. The excitation energies of the low-lying isomeric clusters are less than the bulk metal oxide band gaps and suggest that these clusters could be useful photocatalysts with a visible light source.

Li, Shenggang; Dixon, David A.

2010-02-25

450

Metabolic profiling reveals coordinated switches in primary carbohydrate metabolism in grape berry (Vitis vinifera L.), a non-climacteric fleshy fruit  

PubMed Central

Changes in carbohydrate metabolism during grape berry development play a central role in shaping the final composition of the fruit. The present work aimed to identify metabolic switches during grape development and to provide insights into the timing of developmental regulation of carbohydrate metabolism. Metabolites from central carbon metabolism were measured using high-pressure anion-exchange chromatography coupled to tandem mass spectrometry and enzymatic assays during the development of grape berries from either field-grown vines or fruiting cuttings grown in the greenhouse. Principal component analysis readily discriminated the various stages of berry development, with similar trajectories for field-grown and greenhouse samples. This showed that each stage of fruit development had a characteristic metabolic profile and provided compelling evidence that the fruit-bearing cuttings are a useful model system to investigate regulation of central carbon metabolism in grape berry. The metabolites measured showed tight coordination within their respective pathways, clustering into sugars and sugar-phosphate metabolism, glycolysis, and the tricarboxylic acid cycle. In addition, there was a pronounced shift in metabolism around veraison, characterized by rapidly increasing sugar levels and decreasing organic acids. In contrast, glycolytic intermediates and sugar phosphates declined before veraison but remained fairly stable post-veraison. In summary, these detailed and comprehensive metabolite analyses revealed the timing of important switches in primary carbohydrate metabolism, which could be related to transcriptional and developmental changes within the berry to achieve an integrated understanding of grape berry development. The results are discussed in a meta-analysis comparing metabolic changes in climacteric versus non-climacteric fleshy fruits. PMID:23364938

Gomès, Eric

2013-01-01

451

Ion-exchange properties of 4-vinylpyridine–divinylbenzene-based anion exchangers for ferric chloride complex anions  

Microsoft Academic Search

4-Vinylpyridine–divinylbenzene-based anion exchangers were synthesized by suspension polymerization. Diluent mixtures containing a range of cyclohexane to cyclohexanone ratio were employed to dilute monomers at the time of polymerization. The ion exchangers were characterized for porosity, ion exchange capacity and t1\\/2 for exchange of (FeCl4)? ions adsorbed on resins and those in the surrounding solution. A gradual increase of cyclohexane fraction

Muhammad Arif Malik; Rehana Mukhtar; S. A. R. Zaidi; Shafaat Ahmed; M. Afzal Awan

2002-01-01

452

Enhanced liquid-liquid anion exchange using macrocyclic anion receptors: effect of receptor structure on sulphate-nitrate exchange selectivity  

SciTech Connect

When certain macrocyclic anion receptors are added to a chloroform solution of the nitrate form of a lipophilic quaternary ammonium salt (methyltri-C8,10-ammonium nitrate, Aliquat 336N), the extraction of sulphate from an aqueous sodium nitrate solution via exchange with the organic-phase nitrate is significantly enhanced. Eight macrocycles were surveyed, including two derivatives of a tetraamide macrocycle, five derivatives of calix[4]pyrrole and -decafluorocalix[5]pyrrole. Under the hypothesis that the enhancement originates from sulphate binding by the anion receptors in the chloroform phase, it was possible to obtain reasonable fits to the sulphate distribution survey data based on the formation of 1:1 and 2:1 receptor:sulphate complexes in the chloroform phase. Apparent 1:1 sulphate-binding constants obtained from the model in this system fell in the range . Comparison of the results for the various anion receptors included in this study reveals that sulphate binding is sensitive to the nature of the substituents on the parent macrocycle scaffolds in a way that does not follow straightforwardly from simple chemical expectations, such as electron-withdrawing effects on hydrogen-bond donor strength.

Moyer, Bruce A [ORNL; Sloop Jr, Frederick {Fred} V [ORNL; Fowler, Christopher J [ORNL; Haverlock, Tamara [ORNL; Kang, Hyun Ah [ORNL; Delmau, Laetitia Helene [ORNL; Bau, Diadra [ORNL; Hossain, Alamgir [University of Kansas; Bowman-James, Kristin [University of Kansas; Shriver, James A. [University of Texas; Gross, Mr. Dustin E. [University of Texas, Austin; Bill, Nathan [University of Texas, Austin; Marquez, Manuel [University of Texas; Lynch, Vincent M. [University of Texas, Austin; Sessler, Jonathan L. [University of Texas

2010-01-01

453

Decreased gap junctional communication in neurobiotin microinjected lens epithelial cells after taxol treatment.  

PubMed

The aim of the study was to examine gap-junction-mediated intercellular communication after experimentally induced aggregations of microtubules in cultured bovine lens epithelial cells. Intercellular communication between lens cells appears to be crucial for normal lens homeostasis. However, investigations on the maintenance of direct ion and metabolite exchange via gap junctions and its quantified dependency of cytoskeletal microtubules have not been available under conditions leading to bundling of microtubules. Thus, metabolic coupling of neighboring lens epithelial cells was quantified following microinjections of neurobiotin into single cells under various conditions. In controls, intensive gap-junction-mediated intercellular communication could be documented by dye-spreading of microinjected neurobiotin. In contrast, taxol treatment for 1-3 days impaired, but did not completely block gap-junction-mediated intercellular communication. After depletion of taxol, a complete recovery of intercellular communication was achieved. In addition, confocal laser scanning microscopy and rapid-freeze deep-etch electron microscopy revealed a displacement of actin-filaments from the perinuclear cytoplasm, accompanied by an abnormal aggregation of microtubules after taxol treatment, including impeded translocation of connexin 43 from the cytoplasm into the plasma membrane. Incubation of cells with nocodazole destroyed the microtubule network, accompanied by a clear reduction of plasma-membrane-integrated connexin 43 and significant impairment of dye spreading. Thus, in lens epithelial cells intercellular communication at gap junctions made by connexin 43 depends on the integrity of the microtubule network through the translocation of connexins to the plasma membrane. PMID:15864639

Giessmann, Daniel; Theiss, Carsten; Breipohl, Winrich; Meller, Karl

2005-06-01

454

Linking genome-scale metabolic modeling and genome annotation  

PubMed Central

Summary Genome-scale metabolic network reconstructions, assembled from annotated genomes, serve as a platform for integrating data from heterogeneous sources and generating hypotheses for further experimental validation. Implementing constraint-based modeling techniques such as Flux Balance Analysis (FBA) on network reconstructions allow for interrogating metabolism at a systems-level, which aids in identifying and rectifying gaps in knowledge. With genome sequences for various organisms from prokaryotes to eukaryotes becoming increasingly available, a significant bottleneck lies in the structural and functional annotation of these sequences. Using topologically-based and biologically-inspired metabolic network refinement, we can better characterize enzymatic functions present in an organism and link annotation of these functions to candidate transcripts, both steps that can be experimentally validated. PMID:23417799

Blais, Edik M.; Chavali, Arvind K.; Papin, Jason A.

2014-01-01

455

Confined PBX 9501 gap reinitiation studies  

SciTech Connect

For explosive systems that exhibit gaps or cracks between their internal components (either by design or mechanical failure), measurable time delays exist for detonation waves crossing them. Reinitiation across such gaps is dependent on the type of explosive, gap width, gap morphology, confinement, and temperature effects. To examine this reinitiation effect, a series of tests has been conducted to measure the time delay across a prescribed gap within an 'infinitely' confined PBX 9501 system. Detonation breakout along the explosive surface is measured with a streak camera, and flow features are examined during reinitiation near the gap. Such tests allow for quantitative determination of the time delay corresponding to the time of initiation across a given gap oriented normal to the direction of the detonation wave. Measured time delays can be compared with numerical calculations, making it possible to validate initiation models as well as estimate detonation run-up distances. Understanding this reinitiation behavior is beneficial for the design and evaluation of explosive systems that require precision timing and performance.

Salyer, Terry R [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory; Lam, Kin [Los Alamos National Laboratory

2009-01-01

456

Control of membrane gaps by synaptotagmin-Ca2+ measured with a novel membrane distance ruler  

PubMed Central

Fast synchronous neurotransmitter release is triggered by calcium that activates synaptotagmin-1 (syt-1), resulting in fusion of synaptic vesicles with the presynaptic membrane. Syt-1 possesses two Ca2+-binding C2 domains that tether membranes via interactions with anionic phospholipids. It is capable of crosslinking membranes and has recently been speculated to trigger fusion by decreasing the gap between them. As quantitative information on membrane gaps is key to understanding general cellular mechanisms, including the role of syt-1, we developed a fluorescence-lifetime based inter-membrane distance ruler using membrane-anchored DNAs of various lengths as calibration standards. Wild-type and mutant data provide evidence that full-length syt-1 indeed regulates membrane gaps: without Ca2+, syt-1 maintains membranes at distances of ~7–8?nm. Activation with 100??M Ca2+ decreases the distance to ~5?nm by binding the C2 domains to opposing membranes, respectively. These values reveal that activated syt-1 adjusts membrane distances to the level that promotes SNARE complex assembly. PMID:25500905

Lin, Chao-Chen; Seikowski, Jan; Pérez-Lara, Angel; Jahn, Reinhard; Höbartner, Claudia; Walla, Peter Jomo

2014-01-01

457

MIRAGE: a functional genomics-based approach for metabolic network model reconstruction and its application to cyanobacteria networks.  

PubMed

Genome-scale metabolic network reconstructions are considered a key step in quantifying the genotype-phenotype relationship. We present a novel gap-filling approach, MetabolIc Reconstruction via functionAl GEnomics (MIRAGE), which identifies missing network reactions by integrating metabolic flux analysis and functional genomics data. MIRAGE's performance is demonstrated on the reconstruction of metabolic network models of E. coli and Synechocystis sp. and valida