Generation and phenotypic analysis of mice lacking all urea transporters

PubMed Central

Jiang, Tao; Li, Yingjie; Layton, Anita T.; Wang, Weiling; Sun, Yi; Li, Min; Zhou, Hong; Yang, Baoxue

2017-01-01

Urea transporters (UT) are a family of transmembrane urea-selective channel proteins expressed in multiple tissues and play an important role in the urine concentrating mechanism of the mammalian kidney. UT inhibitors have been identified to have diuretic activity and might be developed as novel diuretics. To determine if functional deficiency of all UTs in all tissues causes physiological abnormality, we established a novel mouse model in which all UTs were knocked out by deleting an 87 kb of DNA fragment containing most parts of Slc14a1 and Slc14a2 genes. Western blot analysis and immunofluorescence confirmed that there is no expression of urea transporter in all-UT-knockout mice. Daily urine output was nearly 3.5-fold higher, with significantly lower urine osmolality, in all-UT-knockout-mice than that in wild-type mice, and urine osmolality was significantly lower. All-UT-knockout mice were not able to increase urinary urea concentration and osmolality after water deprivation, acute urea loading or high protein intake. A computational model that simulated UT knockout mouse models identified the individual contribution of each UT in urine concentrating mechanism. Knocking out all UTs also decreased the blood pressure and promoted the maturation of the male reproductive system. These results revealed that functional deficiency of all UTs caused urea selective urine concentrating defect with little physiological abnormality in extrarenal organs. PMID:27914708

Modulation of kidney urea transporter UT-A3 activity by alpha2,6-sialylation

PubMed Central

Qian, Xiaoqian; Sands, Jeff M.; Song, Xiang; Chen, Guangping

2016-01-01

Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 kDa and 65 kDa. Using sugar specific-binding lectins, the UT-A3 glycosylation profile was examined. The 45 kDa form was pulled down by lectin Con A and GNL, indicating an immature glycan with a high amount of mannose (Man); whereas the 65 kDa form is a mature glycan composed of acetylglucosamine (GlcNAc), poly-N-acetyllactosame (poly-LacNAc) that was pulled down by WGA and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2, 6-sialylation. Activation of PKC by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important in kidney urea reabsorption and the urinary concentrating mechanism. PMID:26972907

Small-Molecule Inhibitors of Urea Transporters

PubMed Central

Verkman, Alan S.; Esteva-Font, Cristina; Cil, Onur; Anderson, Marc O.; Li, Fei; Li, Min; Lei, Tianluo; Ren, Huiwen; Yang, Baoxue

2015-01-01

Urea transporter (UT) proteins, which include isoforms of UT-A in kidney tubule epithelia and UT-B in vasa recta endothelia and erythrocytes, facilitate urinary concentrating function. Inhibitors of urea transporter function have potential clinical applications as sodium-sparing diuretics, or ‘urearetics,’ in edema from different etiologies, such as congestive heart failure and cirrhosis, as well as in syndrome of inappropriate antidiuretic hormone (SIADH). High-throughput screening of drug-like small molecules has identified UT-A and UT-B inhibitors with nanomolar potency. Inhibitors have been identified with different UT-A versus UT-B selectivity profiles and putative binding sites on UT proteins. Studies in rodent models support the utility of UT inhibitors in reducing urinary concentration, though testing in clinically relevant animal models of edema has not yet been done. PMID:25298345

Localization and regulation of a facilitative urea transporter in the kidney of the red-eared slider turtle (Trachemys scripta elegans).

PubMed

Uchiyama, Minoru; Kikuchi, Ryosuke; Konno, Norifumi; Wakasugi, Tatsuya; Matsuda, Kouhei

2009-01-01

Urea is the major excretory end product of nitrogen metabolism in most chelonian reptiles. In the present study, we report the isolation of a 1632 base pair cDNA from turtle kidney with one open reading frame putatively encoding a 403-residue protein, the turtle urea transporter (turtle UT). The first cloned reptilian UT has high homology with UTs (facilitated urea transporters) cloned from vertebrates, and most closely resembles the UT-A subfamily. Injection of turtle UT cRNA into Xenopus oocytes induced a 6-fold increase in [(14)C]urea uptake that was inhibited by phloretin. The turtle UT mRNA expression and tissue distribution were examined by RT-PCR with total RNA from various tissues. Expression of turtle UT mRNA was restricted to the kidney, and no signal was detected in the other tissues, such as brain, heart, alimentary tract and urinary bladder. An approximately 58 kDa protein band was detected in membrane fractions of the kidney by western blot using an affinity-purified antibody that recognized turtle UT expressed in Xenopus oocytes. In an immunohistochemical study using the anti-turtle UT antibody, UT-immunopositive cells were observed along the distal tubule but not in the collecting duct. In turtles under dry conditions, plasma osmolality and urea concentration increased, and using semi-quantitative RT-PCR the UT mRNA expression level in the kidney was found to increase 2-fold compared with control. The present results, taken together, suggest that the turtle UT probably contributes to urea transport in the distal tubule segments of the kidney in response to hyperosmotic stress under dry conditions.

Regulation of renal urea transport by vasopressin.

PubMed

Sands, Jeff M; Blount, Mitsi A; Klein, Janet D

2011-01-01

Terrestrial life would be miserable without the ability to concentrate urine. Production of concentrated urine requires complex interactions among the nephron segments and vasculature in the kidney medulla. In addition to water channels (aquaporins) and sodium transporters, urea transporters are critically important to the theories proposed to explain the physiologic processes occurring when urine is concentrated. Vasopressin (anti-diuretic hormone) is the key hormone regulating the production of concentrated urine. Vasopressin rapidly increases water and urea transport in the terminal inner medullary collecting duct (IMCD). Vasopressin rapidly increases urea permeability in the IMCD through increases in phosphorylation and apical plasma-membrane accumulation of the urea transporter A1 (UT-A1). Vasopressin acts through two cAMP-dependent signaling pathways in the IMCD: protein kinase A and exchange protein activated by cAMP Epac. Protein kinase A phosphorylates UT-A1 at serines 486 and 499. In summary, vasopressin regulates urea transport acutely by increasing UT-A1 phosphorylation and the apical plasma-membrane accumulation of UT-A1 through two cAMP-dependent pathways.

Ammonia excretion and urea handling by fish gills: present understanding and future research challenges.

PubMed

Wilkie, Michael Patrick

2002-08-01

In fresh water fishes, ammonia is excreted across the branchial epithelium via passive NH(3) diffusion. This NH(3) is subsequently trapped as NH(4)(+) in an acidic unstirred boundary layer lying next to the gill, which maintains the blood-to-gill water NH(3) partial pressure gradient. Whole animal, in situ, ultrastructural and molecular approaches suggest that boundary layer acidification results from the hydration of CO(2) in the expired gill water, and to a lesser extent H(+) excretion mediated by apical H(+)-ATPases. Boundary layer acidification is insignificant in highly buffered sea water, where ammonia excretion proceeds via NH(3) diffusion, as well as passive NH(4)(+) diffusion due to the greater ionic permeability of marine fish gills. Although Na(+)/H(+) exchangers (NHE) have been isolated in marine fish gills, possible Na(+)/NH(4)(+) exchange via these proteins awaits evaluation using modern electrophysiological and molecular techniques. Although urea excretion (J(Urea)) was thought to be via passive diffusion, it is now clear that branchial urea handling requires specialized urea transporters. Four urea transporters have been cloned in fishes, including the shark kidney urea transporter (shUT), which is a facilitated urea transporter similar to the mammalian renal UT-A2 transporter. Another urea transporter, characterized but not yet cloned, is the basolateral, Na(+) dependent urea antiporter of the dogfish gill, which is essential for urea retention in ureosmotic elasmobranchs. In ureotelic teleosts such as the Lake Magadi tilapia and the gulf toadfish, the cloned mtUT and tUT are facilitated urea transporters involved in J(Urea). A basolateral urea transporter recently cloned from the gill of the Japanese eel (eUT) may actually be important for urea retention during salt water acclimation. A multi-faceted approach, incorporating whole animal, histological, biochemical, pharmacological, and molecular techniques is required to learn more about the location, mechanism of action, and functional significance of urea transporters in fishes. Copyright 2002 Wiley-Liss, Inc.

Thienoquinolins exert diuresis by strongly inhibiting UT-A urea transporters

PubMed Central

Ren, Huiwen; Wang, Yanhua; Xing, Yongning; Ran, Jianhua; Liu, Ming; Lei, Tianluo; Zhou, Hong; Li, Runtao; Sands, Jeff M.

2014-01-01

Urea transporters (UT) play an important role in the urine concentration mechanism by mediating intrarenal urea recycling, suggesting that UT inhibitors could have therapeutic use as a novel class of diuretic. Recently, we found a thienoquinolin UT inhibitor, PU-14, that exhibited diuretic activity. The purpose of this study was to identify more potent UT inhibitors that strongly inhibit UT-A isoforms in the inner medullary collecting duct (IMCD). Efficient thienoquinolin UT inhibitors were identified by structure-activity relationship analysis. Urea transport inhibition activity was assayed in perfused rat terminal IMCDs. Diuretic activity of the compound was determined in rats and mice using metabolic cages. The results show that the compound PU-48 exhibited potent UT-A inhibition activity. The inhibition was 69.5% with an IC50 of 0.32 μM. PU-48 significantly inhibited urea transport in perfused rat terminal IMCDs. PU-48 caused significant diuresis in UT-B null mice, which indicates that UT-A is the target of PU-48. The diuresis caused by PU-48 did not change blood Na+, K+, or Cl− levels or nonurea solute excretion in rats and mice. No toxicity was detected in cells or animals treated with PU-48. The results indicate that thienoquinolin UT inhibitors induce a diuresis by inhibiting UT-A in the IMCD. This suggests that they may have the potential to be developed as a novel class of diuretics with fewer side effects than classical diuretics. PMID:25298523

Thienoquinolins exert diuresis by strongly inhibiting UT-A urea transporters.

PubMed

Ren, Huiwen; Wang, Yanhua; Xing, Yongning; Ran, Jianhua; Liu, Ming; Lei, Tianluo; Zhou, Hong; Li, Runtao; Sands, Jeff M; Yang, Baoxue

2014-12-15

Urea transporters (UT) play an important role in the urine concentration mechanism by mediating intrarenal urea recycling, suggesting that UT inhibitors could have therapeutic use as a novel class of diuretic. Recently, we found a thienoquinolin UT inhibitor, PU-14, that exhibited diuretic activity. The purpose of this study was to identify more potent UT inhibitors that strongly inhibit UT-A isoforms in the inner medullary collecting duct (IMCD). Efficient thienoquinolin UT inhibitors were identified by structure-activity relationship analysis. Urea transport inhibition activity was assayed in perfused rat terminal IMCDs. Diuretic activity of the compound was determined in rats and mice using metabolic cages. The results show that the compound PU-48 exhibited potent UT-A inhibition activity. The inhibition was 69.5% with an IC50 of 0.32 μM. PU-48 significantly inhibited urea transport in perfused rat terminal IMCDs. PU-48 caused significant diuresis in UT-B null mice, which indicates that UT-A is the target of PU-48. The diuresis caused by PU-48 did not change blood Na(+), K(+), or Cl(-) levels or nonurea solute excretion in rats and mice. No toxicity was detected in cells or animals treated with PU-48. The results indicate that thienoquinolin UT inhibitors induce a diuresis by inhibiting UT-A in the IMCD. This suggests that they may have the potential to be developed as a novel class of diuretics with fewer side effects than classical diuretics. Copyright © 2014 the American Physiological Society.

Modulation of kidney urea transporter UT-A3 activity by alpha2,6-sialylation.

PubMed

Qian, Xiaoqian; Sands, Jeff M; Song, Xiang; Chen, Guangping

2016-07-01

Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however, the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 and 65 kDa. Using sugar-specific binding lectins, the UT-A3 glycosylation profile was examined. The 45-kDa form was pulled down by lectin concanavalin A (Con A) and Galant husnivalis lectin (GNL), indicating an immature glycan with a high amount of mannose (Man), whereas the 65-kDa form is a mature glycan composed of acetylglucosamine (GlcNAc) and poly-N-acetyllactosame (poly-LacNAc) that was pulled down by wheat germ agglutinin (WGA) and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2,6-sialylation. Activation of protein kinase C (PKC) by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. The PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important role in kidney urea reabsorption and the urinary concentrating mechanism.

Regulation of Renal Urea Transport by Vasopressin

PubMed Central

Sands, Jeff M.; Blount, Mitsi A.; Klein, Janet D.

2011-01-01

Terrestrial life would be miserable without the ability to concentrate urine. Production of concentrated urine requires complex interactions among the nephron segments and vasculature in the kidney medulla. In addition to water channels (aquaporins) and sodium transporters, urea transporters are critically important to the theories proposed to explain the physiologic processes occurring when urine is concentrated. Vasopressin (anti-diuretic hormone) is the key hormone regulating the production of concentrated urine. Vasopressin rapidly increases water and urea transport in the terminal inner medullary collecting duct (IMCD). Vasopressin rapidly increases urea permeability in the IMCD through increases in phosphorylation and apical plasma-membrane accumulation of the urea transporter A1 (UT-A1). Vasopressin acts through two cAMP-dependent signaling pathways in the IMCD: protein kinase A and exchange protein activated by cAMP Epac. Protein kinase A phosphorylates UT-A1 at serines 486 and 499. In summary, vasopressin regulates urea transport acutely by increasing UT-A1 phosphorylation and the apical plasma-membrane accumulation of UT-A1 through two cAMP-dependent pathways. PMID:21686211

Structure and permeation mechanism of a mammalian urea transporter

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

Levin, Elena J.; Cao, Yu; Enkavi, Giray

2012-09-17

As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urinary space and the hyperosmotic interstitium. Here we report the first X-ray crystal structure of a mammalian UT, UT-B, at a resolution of 2.36 {angstrom}. UT-B is a homotrimer and each protomer contains a urea conduction pore with a narrow selectivity filter. Structural analyses and molecular dynamics simulations showed that the selectivity filter has twomore » urea binding sites separated by an approximately 5.0 kcal/mol energy barrier. Functional studies showed that the rate of urea conduction in UT-B is increased by hypoosmotic stress, and that the site of osmoregulation coincides with the location of the energy barrier.« less

Structure and permeation mechanism of a mammalian urea transporter

PubMed Central

Levin, Elena J.; Cao, Yu; Enkavi, Giray; Quick, Matthias; Pan, Yaping; Tajkhorshid, Emad; Zhou, Ming

2012-01-01

As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urinary space and the hyperosmotic interstitium. Here we report the first X-ray crystal structure of a mammalian UT, UT-B, at a resolution of 2.36 Å. UT-B is a homotrimer and each protomer contains a urea conduction pore with a narrow selectivity filter. Structural analyses and molecular dynamics simulations showed that the selectivity filter has two urea binding sites separated by an approximately 5.0 kcal/mol energy barrier. Functional studies showed that the rate of urea conduction in UT-B is increased by hypoosmotic stress, and that the site of osmoregulation coincides with the location of the energy barrier. PMID:22733730

Developing Hypothetical Inhibition Mechanism of Novel Urea Transporter B Inhibitor

NASA Astrophysics Data System (ADS)

Li, Min; Tou, Weng Ieong; Zhou, Hong; Li, Fei; Ren, Huiwen; Chen, Calvin Yu-Chian; Yang, Baoxue

2014-07-01

Urea transporter B (UT-B) is a membrane channel protein that specifically transports urea. UT-B null mouse exhibited urea selective urine concentrating ability deficiency, which suggests the potential clinical applications of the UT-B inhibitors as novel diuretics. Primary high-throughput virtual screening (HTVS) of 50000 small-molecular drug-like compounds identified 2319 hit compounds. These 2319 compounds were screened by high-throughput screening using an erythrocyte osmotic lysis assay. Based on the pharmacological data, putative UT-B binding sites were identified by structure-based drug design and validated by ligand-based and QSAR model. Additionally, UT-B structural and functional characteristics under inhibitors treated and untreated conditions were simulated by molecular dynamics (MD). As the result, we identified four classes of compounds with UT-B inhibitory activity and predicted a human UT-B model, based on which computative binding sites were identified and validated. A novel potential mechanism of UT-B inhibitory activity was discovered by comparing UT-B from different species. Results suggest residue PHE198 in rat and mouse UT-B might block the inhibitor migration pathway. Inhibitory mechanisms of UT-B inhibitors and the functions of key residues in UT-B were proposed. The binding site analysis provides a structural basis for lead identification and optimization of UT-B inhibitors.

Renal Phenotype of UT-A Urea Transporter Knockout Mice

PubMed Central

Fenton, Robert A.; Flynn, Anneliese; Shodeinde, Adetola; Smith, Craig P.; Schnermann, Jurgen; Knepper, Mark A.

2006-01-01

The urea transporters UT-A1 and UT-A3 mediate rapid transepithelial urea transport across the inner medullary collecting duct (IMCD). In a previous study, using a new mouse model in which both UT-A1 and UT-A3 were genetically deleted from the IMCD (UT-A1/3−/− mice), we investigated the role of these transporters in the function of the renal inner medulla. Here we report a series of studies investigating more generally the renal phenotype of UT-A1/3−/− mice. Pathological screening revealed abnormalities in both the testis (increased size) and kidney (decreased size and vascular congestion) of UT-A1/3−/− mice. Total urinary nitrate and nitrite excretion rates in UT-A1/3−/− mice were more than double those in wildtype mice. Total renal blood flow was not different between UT-A1/3−/− and wildtype mice, but underwent a greater percentage decrease in response to NG-Nitro-L-arginine Methyl Ester Hydrochloride (L-NAME) infusion. Whole kidney glomerular filtration rate was not different in UT-A1/3−/− mice compared to controls and underwent a similar increase in response to a greater dietary protein intake. Fractional urea excretion was markedly elevated in UT-A1/3−/− mice on a 40% protein diet, reaching 102.4 ± 8.8% of the filtered load, suggesting that there may be active urea secretion along the renal tubule. Although there was a marked urinary concentrating defect in UT-A1/3−/− mice, there was no decrease in aquaporin-2 or -3 expression. Furthermore, although urea accumulation in the inner medulla was markedly attenuated, there was no decrease in NaCl concentration in tissue from outer medulla or 2 levels of the inner medulla. PMID:15829709

Urea transporter UT-B deletion induces DNA damage and apoptosis in mouse bladder urothelium.

PubMed

Dong, Zixun; Ran, Jianhua; Zhou, Hong; Chen, Jihui; Lei, Tianluo; Wang, Weiling; Sun, Yi; Lin, Guiting; Bankir, Lise; Yang, Baoxue

2013-01-01

Previous studies found that urea transporter UT-B is abundantly expressed in bladder urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder urothelium using UT-B knockout mouse model and T24 cell line. Urea and NO measurement, mRNA expression micro-array analysis, light and transmission electron microscopy, apoptosis assays, DNA damage and repair determination, and intracellular signaling examination were performed in UT-B null bladders vs wild-type bladders and in vitro T24 epithelial cells. UT-B was highly expressed in mouse bladder urothelium. The genes, Dcaf11, MCM2-4, Uch-L1, Bnip3 and 45 S pre rRNA, related to DNA damage and apoptosis were significantly regulated in UT-B null urothelium. DNA damage and apoptosis highly occurred in UT-B null urothelium. Urea and NO levels were significantly higher in UT-B null urothelium than that in wild-type, which may affect L-arginine metabolism and the intracellular signals related to DNA damage and apoptosis. These findings were consistent with the in vitro study in T24 cells that, after urea loading, exhibited cell cycle delay and apoptosis. UT-B may play an important role in protecting bladder urothelium by balancing intracellular urea concentration. Disruption of UT-B function induces DNA damage and apoptosis in bladder, which can result in bladder disorders.

Urea Transporter UT-B Deletion Induces DNA Damage and Apoptosis in Mouse Bladder Urothelium

PubMed Central

Zhou, Hong; Chen, Jihui; Lei, Tianluo; Wang, Weiling; Sun, Yi; Lin, Guiting; Bankir, Lise; Yang, Baoxue

2013-01-01

Background Previous studies found that urea transporter UT-B is abundantly expressed in bladder urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder urothelium using UT-B knockout mouse model and T24 cell line. Methodology/Principal Findings Urea and NO measurement, mRNA expression micro-array analysis, light and transmission electron microscopy, apoptosis assays, DNA damage and repair determination, and intracellular signaling examination were performed in UT-B null bladders vs wild-type bladders and in vitro T24 epithelial cells. UT-B was highly expressed in mouse bladder urothelium. The genes, Dcaf11, MCM2-4, Uch-L1, Bnip3 and 45 S pre rRNA, related to DNA damage and apoptosis were significantly regulated in UT-B null urothelium. DNA damage and apoptosis highly occurred in UT-B null urothelium. Urea and NO levels were significantly higher in UT-B null urothelium than that in wild-type, which may affect L-arginine metabolism and the intracellular signals related to DNA damage and apoptosis. These findings were consistent with the in vitro study in T24 cells that, after urea loading, exhibited cell cycle delay and apoptosis. Conclusions/Significance UT-B may play an important role in protecting bladder urothelium by balancing intracellular urea concentration. Disruption of UT-B function induces DNA damage and apoptosis in bladder, which can result in bladder disorders. PMID:24204711

Serosal-to-mucosal urea flux across the isolated ruminal epithelium is mediated via urea transporter-B and aquaporins when Holstein calves are abruptly changed to a moderately fermentable diet.

PubMed

Walpole, M E; Schurmann, B L; Górka, P; Penner, G B; Loewen, M E; Mutsvangwa, T

2015-02-01

Urea transport (UT-B) proteins are known to facilitate urea movement across the ruminal epithelium; however, other mechanisms may be involved as well because inhibiting UT-B does not completely abolish urea transport. Of the aquaporins (AQP), which are a family of membrane-spanning proteins that are predominantly involved in the movement of water, AQP-3, AQP-7, and AQP-10 are also permeable to urea, but it is not clear if they contribute to urea transport across the ruminal epithelium. The objectives of this study were to determine (1) the functional roles of AQP and UT-B in the serosal-to-mucosal urea flux (Jsm-urea) across rumen epithelium; and (2) whether functional adaptation occurs in response to increased diet fermentability. Twenty-five Holstein steer calves (n=5) were assigned to a control diet (CON; 91.5% hay and 8.5% vitamin and mineral supplement) or a medium grain diet (MGD; 41.5% barley grain, 50% hay, and 8.5% vitamin and mineral) that was fed for 3, 7, 14, or 21 d. Calves were killed and ruminal epithelium was collected for mounting in Ussing chambers under short-circuit conditions and for analysis of mRNA abundance of UT-B and AQP-3, AQP-7, and AQP-10. To mimic physiologic conditions, the mucosal buffer (pH 6.2) contained no urea, whereas the serosal buffer (pH 7.4) contained 1 mM urea. The fluxes of (14)C-urea (Jsm-urea; 26 kBq/10 mL) and (3)H-mannitol (Jsm-mannitol; 37 kBq/10 mL) were measured, with Jsm-mannitol being used as an indicator of paracellular or hydrophilic movement. Serosal addition of phloretin (1 mM) was used to inhibit UT-B-mediated urea transport, whereas NiCl2 (1 mM) was used to inhibit AQP-mediated urea transport. Across treatments, the addition of phloretin or NiCl2 reduced the Jsm-urea from 116.5 to 54.0 and 89.5 nmol/(cm(2) × h), respectively. When both inhibitors were added simultaneously, Jsm-urea was further reduced to 36.8 nmol/(cm(2) × h). Phloretin-sensitive and NiCl2-sensitive Jsm-urea were not affected by diet. The Jsm-urea tended to increase linearly as the duration of adaptation to MGD increased, with the lowest Jsm-urea being observed in animals fed CON [107.7 nmol/(cm(2) × h)] and the highest for those fed the MGD for 21 d [144.2 nmol/(cm(2) × h)]. Phloretin-insensitive Jsm-urea tended to increase linearly as the duration of adaptation to MGD increased, whereas NiCl2-insensitive Jsm-urea tended to be affected by diet. Gene transcript abundance for AQP-3 and UT-B in ruminal epithelium increased linearly as the duration of MGD adaptation increased. For AQP-7 and AQP-10, gene transcript abundance in animals that were fed the MGD was greater compared with that of CON animals. These results demonstrate that both AQP and UT-B play significant functional roles in urea transport, and they may play a role in urea transport during dietary adaptation to fermentable carbohydrates. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Salt-sparing diuretic action of a water-soluble urea analog inhibitor of urea transporters UT-A and UT-B in rats

PubMed Central

Cil, Onur; Esteva-Font, Cristina; Tas, Sadik Taskin; Su, Tao; Lee, Sujin; Anderson, Marc O.; Ertunc, Mert; Verkman, A. S.

2015-01-01

Inhibitors of kidney urea transporter (UT) proteins have potential use as salt-sparing diuretics (‘urearetics’) with a different mechanism of action than diuretics that target salt transporters. To study UT inhibition in rats, we screened about 10,000 drugs, natural products and urea analogs for inhibition of rat UT-A1. Drug and natural product screening found nicotine, sanguinarine and an indolcarbonylchromenone with IC50 of 10–20 μM. Urea analog screening found methylacetamide and dimethylthiourea (DMTU). DMTU fully and reversibly inhibited rat UT-A1 and UT-B by a noncompetitive mechanism with IC50 of 2–3 mM. Homology modeling and docking computations suggested DMTU binding sites on rat UT-A1. Following a single intraperitoneal injection of 500 mg/kg DMTU, peak plasma concentration was 9 mM with t1/2 of about 10 hours, and a urine concentration of 20–40 mM. Rats chronically treated with DMTU had a sustained, reversible reduction in urine osmolality from 1800 to 600 mOsm, a 3-fold increase in urine output, and mild hypokalemia. DMTU did not impair urinary concentrating function in rats on a low protein diet. Compared to furosemide-treated rats, the DMTU-treated rats had greater diuresis and reduced urinary salt loss. In a model of Syndrome of Inappropriate Antidiuretic Hormone secretion, DMTU treatment prevented hyponatremia and water retention produced by water-loading in dDAVP-treated rats. Thus, our results establish a rat model of UT inhibition and demonstrate the diuretic efficacy of UT inhibition. PMID:25993324

Salt-sparing diuretic action of a water-soluble urea analog inhibitor of urea transporters UT-A and UT-B in rats.

PubMed

Cil, Onur; Esteva-Font, Cristina; Tas, Sadik Taskin; Su, Tao; Lee, Sujin; Anderson, Marc O; Ertunc, Mert; Verkman, Alan S

2015-08-01

Inhibitors of kidney urea transporter (UT) proteins have potential use as salt-sparing diuretics ('urearetics') with a different mechanism of action than diuretics that target salt transporters. To study UT inhibition in rats, we screened about 10,000 drugs, natural products and urea analogs for inhibition of rat UT-A1. Drug and natural product screening found nicotine, sanguinarine and an indolcarbonylchromenone with IC50 of 10-20 μM. Urea analog screening found methylacetamide and dimethylthiourea (DMTU). DMTU fully and reversibly inhibited rat UT-A1 and UT-B by a noncompetitive mechanism with IC50 of 2-3 mM. Homology modeling and docking computations suggested DMTU binding sites on rat UT-A1. Following a single intraperitoneal injection of 500 mg/kg DMTU, peak plasma concentration was 9 mM with t1/2 of about 10 h, and a urine concentration of 20-40 mM. Rats chronically treated with DMTU had a sustained, reversible reduction in urine osmolality from 1800 to 600 mOsm, a 3-fold increase in urine output, and mild hypokalemia. DMTU did not impair urinary concentrating function in rats on a low protein diet. Compared to furosemide-treated rats, the DMTU-treated rats had greater diuresis and reduced urinary salt loss. In a model of syndrome of inappropriate antidiuretic hormone secretion, DMTU treatment prevented hyponatremia and water retention produced by water-loading in dDAVP-treated rats. Thus, our results establish a rat model of UT inhibition and demonstrate the diuretic efficacy of UT inhibition.

Forskolin stimulation promotes urea transporter UT-A1 ubiquitination, endocytosis, and degradation in MDCK cells

PubMed Central

Su, Hua; Carter, Conner B.; Laur, Oskar; Sands, Jeff M.

2012-01-01

The adenylyl cyclase stimulator forskolin (FSK) stimulates UT-A1 phosphorylation, membrane trafficking, and urea transport activity. Here, we found that FSK stimulation induces UT-A1 ubiquitination in UT-A1 Madin-Darby canine kidney (MDCK) cells. This suggests that phosphorylation by FSK also triggers the protein degradation machinery for UT-A1. UT-A1-MDCK cells were treated with 100 μg/ml cycloheximide to inhibit protein synthesis, with or without 10 μM FSK. Total UT-A1 protein abundance was significantly reduced after FSK treatment, concomitantly ubiquitinated UT-A1 was increased. We then specifically investigated the effect of FSK on UT-A1 expressed on the cell plasma membrane. FSK treatment accelerated UT-A1 removal from the cell plasma membrane by increasing UT-A1 endocytosis as judged by biotinylation/MesNa treatment and confocal microscopy. We further found that inhibition of the clathrin-mediated endocytic pathway, but not the caveolin-mediated endocytic pathway, significantly blocks FSK-stimulated UT-A1 endocytosis. The PKA inhibitor H89 and the proteasome inhibitors MG132 and lactacystin reduced FSK-induced membrane UT-A1 reduction. Our study shows that FSK activates the UT-A1 urea transporter and the activation/phosphorylation subsequently triggers the downregulation of UT-A1, which represents an important mechanism for the cell to return to the basal conditions after vasopressin stimulation. PMID:22914781

Movement of NH3 through the human urea transporter B: a new gas channel

PubMed Central

Musa-Aziz, Raif; Enkavi, Giray; Mahinthichaichan, P.; Tajkhorshid, Emad; Boron, Walter F.

2013-01-01

Aquaporins and Rh proteins can function as gas (CO2 and NH3) channels. The present study explores the urea, H2O, CO2, and NH3 permeability of the human urea transporter B (UT-B) (SLC14A1), expressed in Xenopus oocytes. We monitored urea uptake using [14C]urea and measured osmotic water permeability (Pf) using video microscopy. To obtain a semiquantitative measure of gas permeability, we used microelectrodes to record the maximum transient change in surface pH (ΔpHS) caused by exposing oocytes to 5% CO2/33 mM HCO3− (pHS increase) or 0.5 mM NH3/NH4+ (pHS decrease). UT-B expression increased oocyte permeability to urea by >20-fold, and Pf by 8-fold vs. H2O-injected control oocytes. UT-B expression had no effect on the CO2-induced ΔpHS but doubled the NH3-induced ΔpHS. Phloretin reduced UT-B-dependent urea uptake (Jurea*) by 45%, Pf* by 50%, and (−ΔpHS*)NH3 by 70%. p-Chloromercuribenzene sulfonate reduced Jurea* by 25%, Pf* by 30%, and (ΔpHS*)NH3 by 100%. Molecular dynamics (MD) simulations of membrane-embedded models of UT-B identified the monomeric UT-B pores as the main conduction pathway for both H2O and NH3 and characterized the energetics associated with permeation of these species through the channel. Mutating each of two conserved threonines lining the monomeric urea pores reduced H2O and NH3 permeability. Our data confirm that UT-B has significant H2O permeability and for the first time demonstrate significant NH3 permeability. Thus the UTs become the third family of gas channels. Inhibitor and mutagenesis studies and results of MD simulations suggest that NH3 and H2O pass through the three monomeric urea channels in UT-B. PMID:23552862

Urea transporter proteins as targets for small-molecule diuretics.

PubMed

Esteva-Font, Cristina; Anderson, Marc O; Verkman, Alan S

2015-02-01

Conventional diuretics such as furosemide and thiazides target salt transporters in kidney tubules, but urea transporters (UTs) have emerged as alternative targets. UTs are a family of transmembrane channels expressed in a variety of mammalian tissues, in particular the kidney. UT knockout mice and humans with UT mutations exhibit reduced maximal urinary osmolality, demonstrating that UTs are necessary for the concentration of urine. Small-molecule screening has identified potent and selective inhibitors of UT-A, the UT protein expressed in renal tubule epithelial cells, and UT-B, the UT protein expressed in vasa recta endothelial cells. Data from UT knockout mice and from rodents administered UT inhibitors support the diuretic action of UT inhibition. The kidney-specific expression of UT-A1, together with high selectivity of the small-molecule inhibitors, means that off-target effects of such small-molecule drugs should be minimal. This Review summarizes the structure, expression and function of UTs, and looks at the evidence supporting the validity of UTs as targets for the development of salt-sparing diuretics with a unique mechanism of action. UT-targeted inhibitors may be useful alone or in combination with conventional diuretics for therapy of various oedemas and hyponatraemias, potentially including those refractory to treatment with current diuretics.

Antigenic and functional properties of the human red blood cell urea transporter hUT-B1.

PubMed

Lucien, Nicole; Sidoux-Walter, Frédéric; Roudier, Nathalie; Ripoche, Pierre; Huet, Martine; Trinh-Trang-Tan, Marie-Marcelle; Cartron, Jean-Pierre; Bailly, Pascal

2002-09-13

The Kidd (JK) blood group locus encodes the urea transporter hUT-B1, which is expressed on human red blood cells and other tissues. The common JK*A/JK*B blood group polymorphism is caused by a single nucleotide transition G838A changing Asp-280 to Asn-280 on the polypeptide, and transfection of erythroleukemic K562 cells with hUT-B1 cDNAs carrying either the G838 or the A838 nucleotide substitutions resulted in the isolation of stable clones that expressed the Jk(a) or Jk(b) antigens, respectively, thus providing the first direct demonstration that the hUT-B1 gene encodes the Kidd blood group antigens. In addition, immunochemical analysis of red blood cells demonstrated that hUT-B1 also exhibits ABO determinants attached to the single N-linked sugar chain at Asn-211. Moreover, immunoadsorption studies, using inside-out and right-side-out red cell membrane vesicles as competing antigen, demonstrated that the C- and N-terminal ends of hUT-B1 are oriented intracellularly. Mutagenesis and functional studies by expression in Xenopus oocytes revealed that both cysteines Cys-25 and Cys-30 (but not alone) are essential for plasma membrane addressing. Conversely, the transport function was not affected by the JK*A/JK*B polymorphism, C-terminal deletion (residues 360-389), or mutation of the extracellular N-glycosylation consensus site and remains poorly para-chloromercuribenzene sulfonate (pCMBS)-sensitive. However, transport studies by stopped flow light scattering using Jk-K562 transfectants demonstrated that the hUT-B1-mediated urea transport is pCMBS-sensitive in an erythroid context, as reported previously for the transporter of human red blood cells. Mutagenesis analysis also indicated that Cys-151 and Cys-236, at least alone, are not involved in pCMBS inhibition. Altogether, these antigenic, topologic, and functional properties might have implications into the physiology of hUT-B1 and other members of the urea transporter family.

Physiological and molecular ontogeny of branchial and extra-branchial urea excretion in posthatch rainbow trout (Oncorhynchus mykiss).

PubMed

Zimmer, Alex M; Wood, Chris M

2016-02-01

All teleost fish produce ammonia as a metabolic waste product. In embryos, ammonia excretion is limited by the chorion, and fish must detoxify ammonia by synthesizing urea via the ornithine urea cycle (OUC). Although urea is produced by embryos and larvae, urea excretion (J(urea)) is typically low until yolk sac absorption, increasing thereafter. The aim of this study was to determine the physiological and molecular characteristics of J(urea) by posthatch rainbow trout (Oncorhynchus mykiss). Following hatch, whole body urea concentration decreased over time, while J(urea) increased following yolk sac absorption. From 12 to 40 days posthatch (dph), extra-branchial routes of excretion accounted for the majority of J(urea), while the gills became the dominant site for J(urea) only after 55 dph. This represents the most delayed branchial ontogeny of any process studied to date. Urea transporter (UT) gene expression in the gills and skin increased over development, consistent with increases in branchial and extra-branchial J(urea). Following exposure to 25 mmol/l urea, the accumulation and subsequent elimination of exogenous urea was much greater at 55 dph than 12 dph, consistent with increased UT expression. Notably, UT gene expression in the gills of 55 dph larvae increased in response to high urea. In summary, there is a clear increase in urea transport capacity over posthatch development, despite a decrease in OUC activity. Copyright © 2016 the American Physiological Society.

Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression

PubMed Central

Grether-Beck, Susanne; Felsner, Ingo; Brenden, Heidi; Kohne, Zippora; Majora, Marc; Marini, Alessandra; Jaenicke, Thomas; Rodriguez-Martin, Marina; Trullas, Carles; Hupe, Melanie; Elias, Peter M.; Krutmann, Jean

2012-01-01

Urea is an endogenous metabolite, known to enhance stratum corneum hydration. Yet, topical urea anecdotally also improves permeability barrier function, and it appears to exhibit antimicrobial activity. Hence, we hypothesized that urea is not merely a passive metabolite, but a small-molecule regulator of epidermal structure and function. In 21 human volunteers, topical urea improved barrier function in parallel with enhanced antimicrobial peptide (LL-37 and β-defensin-2) expression. Urea both stimulates expression of, and is transported into keratinocytes by two urea transporters, UT-A1 and UT-A2, and by aquaporin 3, 7 and 9. Inhibitors of these urea transporters block the downstream biological effects of urea, which include increased mRNA and protein levels for: (i) transglutaminase-1, involucrin, loricrin and filaggrin; (ii) epidermal lipid synthetic enzymes, and (iii) cathelicidin/LL-37 and β-defensin-2. Finally, we explored the potential clinical utility of urea, showing that topical urea applications normalized both barrier function and antimicrobial peptide expression in a murine model of atopic dermatitis (AD). Together, these results show that urea is a small-molecule regulator of epidermal permeability barrier function and antimicrobial peptide expression after transporter uptake, followed by gene regulatory activity in normal epidermis, with potential therapeutic applications in diseased skin. PMID:22418868

Modulation of sheep ruminal urea transport by ammonia and pH.

PubMed

Lu, Zhongyan; Stumpff, Friederike; Deiner, Carolin; Rosendahl, Julia; Braun, Hannah; Abdoun, Khalid; Aschenbach, Jörg R; Martens, Holger

2014-09-01

Ruminal fermentation products such as short-chain fatty acids (SCFA) and CO2 acutely stimulate urea transport across the ruminal epithelium in vivo, whereas ammonia has inhibitory effects. Uptake and signaling pathways remain obscure. The ruminal expression of SLC14a1 (UT-B) was studied using polymerase chain reaction (PCR). The functional short-term effects of ammonia on cytosolic pH (pHi) and ruminal urea transport across native epithelia were investigated using pH-sensitive microelectrodes and via flux measurements in Ussing chambers. Two variants (UT-B1 and UT-B2) could be fully sequenced from ovine ruminal cDNA. Functionally, transport was passive and modulated by luminal pH in the presence of SCFA and CO2, rising in response to luminal acidification to a peak value at pH 5.8 and dropping with further acidification, resulting in a bell-shaped curve. Presence of ammonia reduced the amplitude, but not the shape of the relationship between urea flux and pH, so that urea flux remained maximal at pH 5.8. Effects of ammonia were concentration dependent, with saturation at 5 mmol/l. Clamping the transepithelial potential altered the inhibitory potential of ammonia on urea flux. Ammonia depolarized the apical membrane and acidified pHi, suggesting that, at physiological pH (< 7), uptake of NH4 (+) into the cytosol may be a key signaling event regulating ruminal urea transport. We conclude that transport of urea across the ruminal epithelium involves proteins subject to rapid modulation by manipulations that alter pHi and the cytosolic concentration of NH4 (+). Implications for epithelial and ruminal homeostasis are discussed. Copyright © 2014 the American Physiological Society.

Diuresis and reduced urinary osmolality in rats produced by small-molecule UT-A-selective urea transport inhibitors.

PubMed

Esteva-Font, Cristina; Cil, Onur; Phuan, Puay-Wah; Su, Tao; Lee, Sujin; Anderson, Marc O; Verkman, A S

2014-09-01

Urea transport (UT) proteins of the UT-A class are expressed in epithelial cells in kidney tubules, where they are required for the formation of a concentrated urine by countercurrent multiplication. Here, using a recently developed high-throughput assay to identify UT-A inhibitors, a screen of 50,000 synthetic small molecules identified UT-A inhibitors of aryl-thiazole, γ-sultambenzosulfonamide, aminocarbonitrile butene, and 4-isoxazolamide chemical classes. Structure-activity analysis identified compounds that inhibited UT-A selectively by a noncompetitive mechanism with IC50 down to ∼1 μM. Molecular modeling identified putative inhibitor binding sites on rat UT-A. To test compound efficacy in rats, formulations and administration procedures were established to give therapeutic inhibitor concentrations in blood and urine. We found that intravenous administration of an indole thiazole or a γ-sultambenzosulfonamide at 20 mg/kg increased urine output by 3-5-fold and reduced urine osmolality by ∼2-fold compared to vehicle control rats, even under conditions of maximum antidiuresis produced by 1-deamino-8-D-arginine vasopressin (DDAVP). The diuresis was reversible and showed urea > salt excretion. The results provide proof of concept for the diuretic action of UT-A-selective inhibitors. UT-A inhibitors are first in their class salt-sparing diuretics with potential clinical indications in volume-overload edemas and high-vasopressin-associated hyponatremias. © FASEB.

Metformin, an AMPK activator, stimulates the phosphorylation of aquaporin 2 and urea transporter A1 in inner medullary collecting ducts.

PubMed

Klein, Janet D; Wang, Yanhua; Blount, Mitsi A; Molina, Patrick A; LaRocque, Lauren M; Ruiz, Joseph A; Sands, Jeff M

2016-05-15

Nephrogenic diabetes insipidus (NDI) is characterized by production of very large quantities of dilute urine due to an inability of the kidney to respond to vasopressin. Congenital NDI results from mutations in the type 2 vasopressin receptor (V2R) in ∼90% of families. These patients do not have mutations in aquaporin-2 (AQP2) or urea transporter UT-A1 (UT-A1). We tested adenosine monophosphate kinase (AMPK) since it is known to phosphorylate another vasopressin-sensitive transporter, NKCC2 (Na-K-2Cl cotransporter). We found AMPK expressed in rat inner medulla (IM). AMPK directly phosphorylated AQP2 and UT-A1 in vitro. Metformin, an AMPK activator, increased phosphorylation of both AQP2 and UT-A1 in rat inner medullary collecting ducts (IMCDs). Metformin increased the apical plasma membrane accumulation of AQP2, but not UT-A1, in rat IM. Metformin increased both osmotic water permeability and urea permeability in perfused rat terminal IMCDs. These findings suggest that metformin increases osmotic water permeability by increasing AQP2 accumulation in the apical plasma membrane but increases urea permeability by activating UT-A1 already present in the membrane. Lastly, metformin increased urine osmolality in mice lacking a V2R, a mouse model of congenital NDI. We conclude that AMPK activation by metformin mimics many of the mechanisms by which vasopressin increases urine-concentrating ability. These findings suggest that metformin may be a novel therapeutic option for congenital NDI due to V2R mutations. Copyright © 2016 the American Physiological Society.

Metformin, an AMPK activator, stimulates the phosphorylation of aquaporin 2 and urea transporter A1 in inner medullary collecting ducts

PubMed Central

Wang, Yanhua; Blount, Mitsi A.; Molina, Patrick A.; LaRocque, Lauren M.; Ruiz, Joseph A.

2016-01-01

Nephrogenic diabetes insipidus (NDI) is characterized by production of very large quantities of dilute urine due to an inability of the kidney to respond to vasopressin. Congenital NDI results from mutations in the type 2 vasopressin receptor (V2R) in ∼90% of families. These patients do not have mutations in aquaporin-2 (AQP2) or urea transporter UT-A1 (UT-A1). We tested adenosine monophosphate kinase (AMPK) since it is known to phosphorylate another vasopressin-sensitive transporter, NKCC2 (Na-K-2Cl cotransporter). We found AMPK expressed in rat inner medulla (IM). AMPK directly phosphorylated AQP2 and UT-A1 in vitro. Metformin, an AMPK activator, increased phosphorylation of both AQP2 and UT-A1 in rat inner medullary collecting ducts (IMCDs). Metformin increased the apical plasma membrane accumulation of AQP2, but not UT-A1, in rat IM. Metformin increased both osmotic water permeability and urea permeability in perfused rat terminal IMCDs. These findings suggest that metformin increases osmotic water permeability by increasing AQP2 accumulation in the apical plasma membrane but increases urea permeability by activating UT-A1 already present in the membrane. Lastly, metformin increased urine osmolality in mice lacking a V2R, a mouse model of congenital NDI. We conclude that AMPK activation by metformin mimics many of the mechanisms by which vasopressin increases urine-concentrating ability. These findings suggest that metformin may be a novel therapeutic option for congenital NDI due to V2R mutations. PMID:26962099

Physiological and molecular ontogeny of branchial and extra-branchial urea excretion in posthatch rainbow trout (Oncorhynchus mykiss)

PubMed Central

Wood, Chris M.

2015-01-01

All teleost fish produce ammonia as a metabolic waste product. In embryos, ammonia excretion is limited by the chorion, and fish must detoxify ammonia by synthesizing urea via the ornithine urea cycle (OUC). Although urea is produced by embryos and larvae, urea excretion (Jurea) is typically low until yolk sac absorption, increasing thereafter. The aim of this study was to determine the physiological and molecular characteristics of Jurea by posthatch rainbow trout (Oncorhynchus mykiss). Following hatch, whole body urea concentration decreased over time, while Jurea increased following yolk sac absorption. From 12 to 40 days posthatch (dph), extra-branchial routes of excretion accounted for the majority of Jurea, while the gills became the dominant site for Jurea only after 55 dph. This represents the most delayed branchial ontogeny of any process studied to date. Urea transporter (UT) gene expression in the gills and skin increased over development, consistent with increases in branchial and extra-branchial Jurea. Following exposure to 25 mmol/l urea, the accumulation and subsequent elimination of exogenous urea was much greater at 55 dph than 12 dph, consistent with increased UT expression. Notably, UT gene expression in the gills of 55 dph larvae increased in response to high urea. In summary, there is a clear increase in urea transport capacity over posthatch development, despite a decrease in OUC activity. PMID:26608657

The UT-A Urea Transporter Promoter, UT-Aα, Targets Principal Cells of the Renal Inner Medullary Collecting Duct

PubMed Central

Fenton, Robert A.; Shodeinde, Adetola; Knepper, Mark A.

2006-01-01

The urea transporters, UT-A1 and UT-A3, two members of the UT-A gene family, are localized to the terminal portion of the inner medullary collecting duct (IMCD). In this manuscript, we demonstrate that 4.2-kb of the 5′-flanking region of the UT-A gene (UT-Aα promoter) is sufficient to drive the IMCD-specific expression of a heterologous reporter gene, β-galactosidase (β-Gal), in transgenic mice. RT-PCR, immunoblotting and immunohistochemistry demonstrate that within the kidney, transgene expression is confined to the terminal portion of the IMCD. Co-localization studies with aquaporin 2 show that expression is localized to the principal cells of the IMCD2 and IMCD3 regions. Utilizing β-Gal activity assays, we further show that within the kidney, the β-Gal transgene can be regulated by both water restriction and glucocorticoids, similar to the regulation of the endogenous UT-A gene. These results demonstrate that 4.2-kb of the UT-Aα promoter is sufficient to drive expression of a heterologous reporter gene in a tissue-specific and cell-specific fashion in transgenic mice PMID:16091580

Urea-Aromatic Stacking and Concerted Urea Transport: Conserved Mechanisms in Urea Transporters Revealed by Molecular Dynamics.

PubMed

Padhi, Siladitya; Priyakumar, U Deva

2016-10-11

Urea transporters are membrane proteins that selectively allow urea molecules to pass through. It is not clear how these transporters allow rapid conduction of urea, a polar molecule, in spite of the presence of a hydrophobic constriction lined by aromatic rings. The current study elucidates the mechanism that is responsible for this rapid conduction by performing free energy calculations on the transporter dvUT with a cumulative sampling time of about 1.3 μs. A parallel arrangement of aromatic rings in the pore enables stacking of urea with these rings, which, in turn, lowers the energy barrier for urea transport. Such interaction of the rings with urea is proposed to be a conserved mechanism across all urea-conducting proteins. The free energy landscape for the permeation of multiple urea molecules reveals an interplay between interurea interaction and the solvation state of the urea molecules. This is for the first time that multiple molecule permeation through any small molecule transporter has been modeled.

Glycogen Synthase Kinase-3 Modulates Hyperosmotic-Induced Urea Transporter A1 Relocation in the Inner Medullary Collecting Duct Cells.

PubMed

Li, Yong-Xia; Huang, Yun; Liu, Song; Mao, Yan; Yuan, Cheng-Yan; Yang, Xiao; Yao, Li-Jun

2016-01-01

Glycogen synthase kinase 3 (GSK3) regulates urine concentration by mediating the vasopressin-induced aquaporin 2 expression and water permeability, although it is unknown whether GSK3 also mediates the accumulation of the urea transporter A1 (UT-A1). The aim of this study is to investigate the effect of GSK3 on UT-A1 distribution. Mouse inner medullary collecting duct 3 cells were transfected with UT-A1-GFP construct. The stable transfected cells were cultured under hypertonic conditions, treated with GSK3 inhibitor lithium chloride, GSK3 activator, lysosome or proteasome inhibitor. The expression levels of UT-A1, GSK3, and phospho-GSK3 were analyzed using western blot. The interaction between UT-A1 and the Golgi apparatus was examined using confocal immunofluorescence microscope. The UT-A1 trafficking was examined using the biotinylation of surface membranes. UT-A1 dissociated away from the Golgi apparatus and translocated to the plasma membrane under hypertonic-NaCl and NaCl plus urea stimulation. This movement was accompanied by the increased phosphorylation of GSK3 and its localization on the cellular membrane. Moreover, these results were duplicated by treating the cells with the GSK3 inhibitor, and by contrast, were partially reversed by the GSK3 activator. Treating cells with a lysosome or proteasome inhibitor failed to attenuate the effects of hypertonic stimulus, indicating that the loss of UT-A1 from the Golgi was not due to degradation. Our results suggest that GSK3 may in part modulate the hypertonic-induced intracellular UT-A1 redistribution and its accumulation on the plasma membrane, which may constitute another mechanism by which GSK3 modulates urine concentration. © 2016 S. Karger AG, Basel.

Role of protein kinase C-α in hypertonicity-stimulated urea permeability in mouse inner medullary collecting ducts.

PubMed

Wang, Yanhua; Klein, Janet D; Froehlich, Otto; Sands, Jeff M

2013-01-15

The kidney's ability to concentrate urine is vitally important to our quality of life. In the hypertonic environment of the kidney, urea transporters must be regulated to optimize function. We previously showed that hypertonicity increases urea permeability and that the protein kinase C (PKC) blockers chelerythrine and rottlerin decreased hypertonicity-stimulated urea permeability in rat inner medullary collecting ducts (IMCDs). Because PKCα knockout (PKCα(-/-)) mice have a urine-concentrating defect, we tested the effect of hypertonicity on urea permeability in isolated perfused mouse IMCDs. Increasing the osmolality of perfusate and bath from 290 to 690 mosmol/kgH(2)O did not change urea permeability in PKCα(-/-) mice but significantly increased urea permeability in wild-type mice. To determine whether the response to protein kinase A was also missing in IMCDs of PKCα(-/-) mice, tubules were treated with vasopressin and subsequently with the PKC stimulator phorbol dibutyrate (PDBu). Vasopressin stimulated urea permeability in PKCα(-/-) mice. Like vasopressin, forskolin stimulated urea permeability in PKCα(-/-) mice. We previously showed that, in rats, vasopressin and PDBu have additive stimulatory effects on urea permeability. In contrast, in PKCα(-/-) mice, PDBu did not further increase vasopressin-stimulated urea permeability. Western blot analysis showed that expression of the UT-A1 urea transporter in IMCDs was increased in response to vasopressin in wild-type mice as well as PKCα(-/-) mice. Hypertonicity increased UT-A1 phosphorylation in wild-type mice but not in PKCα(-/-) mice. We conclude that PKCα mediates hypertonicity-stimulated urea transport but is not necessary for vasopressin stimulation of urea permeability in mouse IMCDs.

Chronic kidney disease, uremic milieu, and its effects on gut bacterial microbiota dysbiosis.

PubMed

Chaves, Lee D; McSkimming, Daniel I; Bryniarski, Mark A; Honan, Amanda M; Abyad, Sham; Thomas, Shruthi A; Wells, Steven; Buck, Michael J; Sun, Yijun; Genco, Robert J; Quigg, Richard J; Yacoub, Rabi

2018-04-25

Several lines of evidence suggest that gut bacterial microbiota is altered in patients with chronic kidney disease (CKD), though the mechanism of which this dysbiosis takes place is not well understood. Recent studies delineated changes in gut microbiota in both CKD patients and experimental animal models using microarray chips. We present 16S ribosomal RNA gene sequencing of both stool pellets and small bowel contents of C57Bl/6J mice that underwent a remnant kidney model, and establish that changes in microbiota take place in the early gastrointestinal track. Increased intestinal urea concertation has been hypothesized as a leading contributor for dysbiotic changes in CKD. We show that urea transporters UT-A and UT-B mRNA are both expressed throughout the whole gastrointestinal track. The noted increase in intestinal urea concentration appears to be independent of urea transporters' expression. Urea supplementation in drinking water resulted in alteration in bacterial gut microbiota that is quite different than that seen in CKD. This indicates that increased intestinal urea concentration might not fully explain the CKD associated dysbiosis.

Role of rumen butyrate in regulation of nitrogen utilization and urea nitrogen kinetics in growing sheep

USDA-ARS?s Scientific Manuscript database

Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling based on increased expression of urea transporter (UT-B) in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concent...

Role of protein kinase C-α in hypertonicity-stimulated urea permeability in mouse inner medullary collecting ducts

PubMed Central

Klein, Janet D.; Froehlich, Otto; Sands, Jeff M.

2013-01-01

The kidney's ability to concentrate urine is vitally important to our quality of life. In the hypertonic environment of the kidney, urea transporters must be regulated to optimize function. We previously showed that hypertonicity increases urea permeability and that the protein kinase C (PKC) blockers chelerythrine and rottlerin decreased hypertonicity-stimulated urea permeability in rat inner medullary collecting ducts (IMCDs). Because PKCα knockout (PKCα−/−) mice have a urine-concentrating defect, we tested the effect of hypertonicity on urea permeability in isolated perfused mouse IMCDs. Increasing the osmolality of perfusate and bath from 290 to 690 mosmol/kgH2O did not change urea permeability in PKCα−/− mice but significantly increased urea permeability in wild-type mice. To determine whether the response to protein kinase A was also missing in IMCDs of PKCα−/− mice, tubules were treated with vasopressin and subsequently with the PKC stimulator phorbol dibutyrate (PDBu). Vasopressin stimulated urea permeability in PKCα−/− mice. Like vasopressin, forskolin stimulated urea permeability in PKCα−/− mice. We previously showed that, in rats, vasopressin and PDBu have additive stimulatory effects on urea permeability. In contrast, in PKCα−/− mice, PDBu did not further increase vasopressin-stimulated urea permeability. Western blot analysis showed that expression of the UT-A1 urea transporter in IMCDs was increased in response to vasopressin in wild-type mice as well as PKCα−/− mice. Hypertonicity increased UT-A1 phosphorylation in wild-type mice but not in PKCα−/− mice. We conclude that PKCα mediates hypertonicity-stimulated urea transport but is not necessary for vasopressin stimulation of urea permeability in mouse IMCDs. PMID:23097465

RNA-Seq analysis of glycosylation related gene expression in STZ-induced diabetic rat kidney

USDA-ARS?s Scientific Manuscript database

The UT-A1 urea transporter is crucial to the kidney’s ability to generate the concentrated urine. Native UT-A1 from kidney inner medulla (IM) is a heavily glycosylated protein with two glycosylation forms of 97 and 117 kDa. In diabetes, protein abundance, particularly the 117 kD isoform, is si...

Body fluid osmolytes and urea and ammonia flux in the colon of two chondrichthyan fishes, the ratfish, Hydrolagus colliei, and spiny dogfish, Squalus acanthias.

PubMed

Anderson, W Gary; Nawata, C Michele; Wood, Chris M; Piercey-Normore, Michele D; Weihrauch, Dirk

2012-01-01

The present study has examined the role of the colon in regulating ammonia and urea nitrogen balance in two species of chondrichthyans, the ratfish, Hydrolagus colliei (a holocephalan) and the spiny dogfish, Squalus acanthias (an elasmobranch). Stripped colonic tissue from both the dogfish and ratfish was mounted in an Ussing chamber and in both species bi-directional urea flux was found to be negligible. Urea uptake by the mucosa and serosa of the isolated colonic epithelium through accumulation of (14)C-urea was determined to be 2.8 and 6.2 fold greater in the mucosa of the dogfish compared to the serosa of the dogfish and the mucosa of the ratfish respectively. Furthermore, there was no difference between serosal and mucosal accumulation of (14)C-urea in the ratfish. Through the addition of 2mM NH(4)Cl to the mucosal side of each preparation the potential for ammonia flux was also examined. This was again found to be negligible in both species suggesting that the colon is an extremely tight epithelium to the movement of both urea and ammonia. Plasma, chyme and bile fluid samples were also taken from the agastric ratfish and were compared with solute concentrations of equivalent body fluids in the dogfish. Finally molecular analysis revealed expression of 3 isoforms of the urea transport protein (UT) and an ammonia transport protein (Rhbg) in the gill, intestine, kidney and colon of the ratfish. Partial nucleotide sequences of the UT-1, 2 and 3 isoforms in the ratfish had 95, 95 and 92% identity to the equivalent UT isoforms recently identified in another holocephalan, the elephantfish, Callorhinchus milii. Finally, the nucleotide sequence of the Rhbg identified in the ratfish had 73% identity to the Rhbg protein recently identified in the little skate, Leucoraja erinacea. Copyright © 2011 Elsevier Inc. All rights reserved.

Chronic use of chloroquine disrupts the urine concentration mechanism by lowering cAMP levels in the inner medulla

PubMed Central

von Bergen, Tobias N.

2012-01-01

Chloroquine, a widely used anti-malaria drug, has gained popularity for the treatment of rheumatoid arthritis, systemic lupus erythematosus (SLE), and human immunodeficiency virus (HIV). Unfortunately, chloroquine may also negatively impact renal function for patients whose fluid and electrolyte homeostasis is already compromised by diseases. Chronic administration of chloroquine also results in polyuria, which may be explained by suppression of the antidiuretic response of vasopressin. Several of the transporters responsible for concentrating urine are vasopressin-sensitive including the urea transporters UT-A1 and UT-A3, the water channel aquaporin-2 (AQP2), and the Na+-K+-2Cl− cotransporter (NKCC2). To examine the effect of chloroquine on these transporters, Sprague-Dawley rats received daily subcutaneous injections of 80 mg·kg−1·day−1 of chloroquine for 4 days. Twenty-four hour urine output was twofold higher, and urine osmolality was decreased by twofold in chloroquine-treated rats compared with controls. Urine analysis of treated rats detected the presence chloroquine as well as decreased urine urea and cAMP levels compared with control rats. Western blot analysis showed a downregulation of AQP2 and NKCC2 transporters; however, UT-A1 and UT-A3 abundances were unaffected by chloroquine treatment. Immunohistochemistry showed a marked reduction of UT-A1 and AQP2 in the apical membrane in inner medullary collecting ducts of chloroquine-treated rats. In conclusion, chloroquine-induced polyuria likely occurs as a result of lowered cAMP production. These findings suggest that chronic chloroquine treatment would exacerbate the already compromised fluid homeostasis observed in diseases like chronic kidney disease. PMID:22791344

New insights into urea and glucose handling by the kidney, and the urine concentrating mechanism.

PubMed

Bankir, Lise; Yang, Baoxue

2012-06-01

The mechanism by which urine is concentrated in the mammalian kidney remains incompletely understood. Urea is the dominant urinary osmole in most mammals and may be concentrated a 100-fold above its plasma level in humans and even more in rodents. Several facilitated urea transporters have been cloned. The phenotypes of mice with deletion of the transporters expressed in the kidney have challenged two previously well-accepted paradigms regarding urea and sodium handling in the renal medulla but have provided no alternative explanation for the accumulation of solutes that occurs in the inner medulla. In this review, we present evidence supporting the existence of an active urea secretion in the pars recta of the proximal tubule and explain how it changes our views regarding intrarenal urea handling and UT-A2 function. The transporter responsible for this secretion could be SGLT1, a sodium-glucose cotransporter that also transports urea. Glucagon may have a role in the regulation of this secretion. Further, we describe a possible transfer of osmotic energy from the outer to the inner medulla via an intrarenal Cori cycle converting glucose to lactate and back. Finally, we propose that an active urea transporter, expressed in the urothelium, may continuously reclaim urea that diffuses out of the ureter and bladder. These hypotheses are all based on published findings. They may not all be confirmed later on, but we hope they will stimulate further research in new directions.

Urea transporters and sweat response to uremia.

PubMed

Keller, Raymond W; Bailey, James L; Wang, Yanhua; Klein, Janet D; Sands, Jeff M

2016-06-01

In humans, urea is excreted in sweat, largely through the eccrine sweat gland. The urea concentration in human sweat is elevated when compared to blood urea nitrogen. The sweat urea nitrogen (UN) of patients with end-stage kidney disease (ESRD) is increased when compared with healthy humans. The ability to produce sweat is maintained in the overwhelming majority of ESRD patients. A comprehensive literature review found no reports of sweat UN neither in healthy rodents nor in rodent models of chronic kidney disease (CKD). Therefore, this study measured sweat UN concentrations in healthy and uremic rats. Uninephrectomy followed by renal artery ligation was used to remove 5/6 of renal function. Rats were then fed a high-protein diet to induce uremia. Pilocarpine was used to induce sweating. Sweat droplets were collected under oil. Sweat UN was measured with a urease assay. Serum UN was measured using a fluorescent ortho-pthalaldehyde reaction. Immunohistochemistry (IHC) was accomplished with a horseradish peroxidase and diaminobenzidine technique. Sweat UN in uremic rats was elevated greater than two times compared to healthy pair-fed controls (220 ± 17 and 91 ± 15 mmol/L, respectively). Post hoc analysis showed a significant difference between male and female uremic sweat UN (279 ± 38 and 177 ± 11 mmol/L, respectively.) IHC shows, for the first time, the presence of the urea transporters UT-B and UT-A2 in both healthy and uremic rat cutaneous structures. Future studies will use this model to elucidate how rat sweat UN and other solute excretion is altered by commonly prescribed diuretics. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Urea and urine concentrating ability in mice lacking AQP1 and AQP3.

PubMed

Zhao, Dan; Bankir, Lise; Qian, Liman; Yang, Dayu; Yang, Baoxue

2006-08-01

Aquaporin-1 (AQP1) and aquaporin-3 (AQP3) water channels expressed in the kidney play a critical role in the urine concentrating mechanism. Mice with AQP1 or AQP3 deletion have a urinary concentrating defect. To better characterize this defect, we studied the influence of an acute urea load (300 mumol ip) in conscious AQP1-null, AQP3-null, and wild-type mice. Urine was collected and assayed every 2 h, from 2 h before (baseline) to 8 h after the urea load. Mice of all genotypes excreted the urea load in approximately 4 h with the same time course. Interestingly, despite their low baseline, the AQP3-null mice raised their urine osmolality and urea concentration progressively after the urea load to values almost equal to those in wild-type mice at 8 h. In contrast, urine non-urea solute concentration did not change. Urine volume fell in the last 4 h to about one-fourth of basal values. AQP1-null mice increased their urine flow rate much more than AQP3-null mice and showed no change in urine osmolality and urea concentration. The urea load strongly upregulated urea transporter UT-A3 expression in all three genotypes. These observations show that the lack of AQP3 does not interfere with the ability of the kidney to concentrate urea but impairs its ability to concentrate other solutes. This solute-selective response could result from the capacity of AQP3 to transport not only water but also urea. The results suggest a novel role for AQP3 in non-urea solute concentration in the urine.

Effect of protein supplementation on expression and distribution of urea transporter-B in lambs fed low-quality forage.

PubMed

Ludden, P A; Stohrer, R M; Austin, K J; Atkinson, R L; Belden, E L; Harlow, H J

2009-04-01

Two experiments were conducted to determine the effects of ruminal protein degradability, supplementation frequency, and increasing dietary protein on the expression and distribution of urea transporter-B (UT-B) in lambs fed low-quality forage (mature crested wheatgrass hay; 4.2 to 4.7% CP). In Exp. 1, 15 Dorset wether lambs (initial BW=45.8+/-1.3 kg) were blocked by initial BW and assigned to 1 of 3 treatments within a randomized complete block design for 28 d, with supplements fed to achieve 7, 10, or 13% total dietary CP. In Exp. 2, 13 Dorset wether lambs (initial BW=34+/-4 kg) were used in a completely randomized design and given 1 of 4 isonitrogenous supplements: 1) ruminally degradable protein (RDP) fed daily (n=3), 2) RDP fed on alternate days (n=3), 3) ruminally undegradable protein (RUP) fed on alternate days (n=3), or 4) a 50:50 mixture of RDP and RUP fed on alternate days (n=4) for 18 d. Alternate-day treatments were fed at twice that of daily supplementation. On the last day of both experiments, lambs were killed and samples taken for Western blot analyses for UT-B. Immunoblotting using a rabbit polyclonal antibody to UT-B confirmed the presence of distinct 32-kDa (consistent with a nonglycosylated UT-B protein) and 47-kDa (probable N-glycosylated form of UT-B) protein bands in all 9 tissues analyzed. In both experiments, the liver, dorsal rumen, reticulum, and ventral rumen displayed strong bands at 32 kDa and lighter bands at 47 kDa, whereas the cecum, large colon, spiral colon, and parotid salivary gland displayed slight 32-kDa bands and stronger, more visible bands at 47 kDa. Both protein bands were apparent in the kidney at similar visual intensities in Exp. 1, whereas the relative intensities of the 2 UT-B bands in the kidney were variable, and appeared somewhat reciprocal among animals in Exp. 2. Although the abundance of the 47-kDa UT-B band in the ventral rumen was greater (P=0.03) in lambs fed RDP daily in Exp. 2, no other treatment differences (P >or= 0.15 to 0.99) in the abundance of the 32- or 47-kDa UT-B proteins within tissues were observed in either experiment. Although protein supplementation strategy had little effect on UT-B expression in tissues other than the ventral rumen, differences in the degree of glycosylation of UT-B across tissues may provide insight into its regulation.

Effects of partial ruminal defaunation on urea-nitrogen recycling, nitrogen metabolism, and microbial nitrogen supply in growing lambs fed low or high dietary crude protein concentrations.

PubMed

Kiran, D; Mutsvangwa, T

2010-03-01

Urea-nitrogen recycling to the gastrointestinal tract (GIT), N metabolism, and urea transporter-B (UT-B) mRNA abundance in ruminal epithelium were evaluated in partially defaunated (PDFAUN) and faunated (FAUN) growing lambs fed 2 levels (10%, low, or 15%, high) of dietary CP (DM basis). Four Suffolk ram lambs (43.9 +/- 1.4 kg initial BW) were used in a 4 x 4 Latin square design with 27-d periods. Sunflower oil was fed (6%; DM basis) as an anti-protozoal agent. Nitrogen balance was measured from d 22 to 26, with concurrent measurement of urea-N kinetics using continuous intrajugular infusions of [(15)N(15)N]-urea. Feeding sunflower oil decreased (P < 0.01) total ruminal protozoa by 88%, and this was associated with a decrease (P < 0.01) in ruminal ammonia-N concentrations. Endogenous production of urea-N (UER; 26.1 vs. 34.6 g/d) and urea-N loss in urine (UUE; 10.1 vs. 15.7 g/d) were less (P < 0.01), and urea-N entering the GIT (GER; 16.0 vs. 18.9 g/d) tended to be less (P = 0.06) in PDFAUN as compared with FAUN lambs. However, as a proportion of UER, GER was greater (P < 0.01) and the proportion of recycled urea-N that was utilized for anabolism (i.e., UUA) tended to be greater (P = 0.09) in PDFAUN lambs. Partial defaunation increased (P < 0.01) microbial N supply. The UER, GER, and UUE were greater (P < 0.01) in lambs fed the high diet. However, as a proportion of UER, GER and its anabolic use were greater (P < 0.01) in lambs fed the low diet. The expression of UT-B mRNA in PDFAUN lambs was numerically greater (by 20%; P = 0.15) compared with FAUN lambs. In summary, results indicate that part of the mechanism for improved N utilization in defaunated ruminants is an increase in the proportion of endogenous urea-N output that is recycled to the GIT, thus potentially providing additional N for microbial growth.

Architecture of the human renal inner medulla and functional implications

PubMed Central

Wei, Guojun; Rosen, Seymour; Dantzler, William H.

2015-01-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. PMID:26290371

Extrinsic nerves are not involved in branchial 5-HT dynamics or pulsatile urea excretion in Gulf toadfish, Opsanus beta.

PubMed

Cartolano, Maria C; Amador, Molly H B; Tzaneva, Velislava; Milsom, William K; McDonald, M Danielle

2017-12-01

Gulf toadfish (Opsanus beta) can switch from continuously excreting ammonia as their primary nitrogenous waste to excreting predominantly urea in distinct pulses. Previous studies have shown that the neurotransmitter serotonin (5-HT) is involved in controlling this process, but it is unknown if 5-HT availability is under central nervous control or if the 5-HT signal originates from a peripheral source. Following up on a previous study, cranial nerves IX (glossopharyngeal) and X (vagus) were sectioned to further characterize their role in controlling pulsatile urea excretion and 5-HT release within the gill. In contrast to an earlier study, nerve sectioning did not result in a change in urea pulse frequency. Total urea excretion, average pulse size, total nitrogen excretion, and percent ureotely were reduced the first day post-surgery in nerve-sectioned fish but recovered by 72h post-surgery. Nerve sectioning also had no effect on toadfish urea transporter (tUT), 5-HT transporter (SERT), or 5-HT 2A receptor mRNA expression or 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) abundance in the gill, all of which were found consistently across the three gill arches except 5-HIAA, which was undetectable in the first gill arch. Our findings indicate that the central nervous system does not directly control pulsatile urea excretion or local changes in gill 5-HT and 5-HIAA abundance. Copyright © 2017 Elsevier Inc. All rights reserved.

Architecture of the human renal inner medulla and functional implications.

PubMed

Wei, Guojun; Rosen, Seymour; Dantzler, William H; Pannabecker, Thomas L

2015-10-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. Copyright © 2015 the American Physiological Society.

Structural, optical, thermal and mechanical properties of Urea tartaric acid single crystals.

PubMed

Vinothkumar, P; Rajeswari, K; Kumar, R Mohan; Bhaskaran, A

2015-06-15

Urea tartaric acid (UT) an organic nonlinear optical (NLO) material was synthesized from aqueous solution and the crystals were grown by the slow evaporation technique. The single crystal X-ray diffraction (XRD) analysis revealed that the UT crystal belongs to the orthorhombic system. The functional groups of UT have been identified by the Fourier transform infrared spectral studies. The optical transparent window in the visible and near the IR regions was investigated. The transmittance of UT has been used to calculate the refractive index (n) as a function of the wavelength. The nonlinear optical property of the grown crystal has been confirmed by the Kurtz powder second harmonic generation test. The birefringence of the crystal was determined using a tungsten halogen lamp source. The laser induced surface damage threshold for the grown crystal was measured using the Nd:YAG laser. The anisotropic in mechanical property of the grown crystals was studied using Vicker's microhardness tester at different planes. The etch pit density of UT crystals was investigated. The thermal behavior of UT was investigated using the TG-DTA and DSC studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Erythrocyte permeability to urea and water: comparative study in rodents, ruminants, carnivores, humans, and birds.

PubMed

Liu, Lifeng; Lei, Tianluo; Bankir, Lise; Zhao, Dan; Gai, Xiaodong; Zhao, Xuejian; Yang, Baoxue

2011-01-01

Mammalian erythrocytes exhibit high urea permeability (P (urea)) due to UT-B expression in their cytoplasmic membrane. This high P (urea) allows fast equilibration of urea in erythrocytes during their transit in the hyperosmotic renal medulla. It also allows more urea (in addition to that in plasma) to participate in counter-current exchange between ascending and descending vasa recta, thus improving the trapping of urea in the medulla and improving urine concentrating ability. To determine if P (urea) in erythrocytes is related to diet and urine concentrating ability, we measured P (urea) in erythrocytes from 11 different mammals and 5 birds using stopped-flow light scattering. Carnivores (dog, fox, cat) exhibited high P (urea) (in x10(-5) cm/s, 5.3 ± 0.6, 3.8 ± 0.5 and 2.8 ± 0.7, respectively). In contrast, herbivores (cow, donkey, sheep) showed much lower P (urea) (0.8 ± 0.2, 0.7 ± 0.2, 1.0 ± 0.1, respectively). Erythrocyte P (urea) in human (1.1 ± 0.2), and pig (1.5 ± 0.1), the two omnivores, was intermediate. Rodents and lagomorphs (mouse, rat, rabbit) had P (urea) intermediate between carnivores and omnivores (3.3 ± 0.4, 2.5 ± 0.3 and 2.4 ± 0.3, respectively). Birds that do not excrete urea and do not express UT-B in their erythrocytes had very low values (<0.1 × 10(-5) cm/s). In contrast to P (urea), water permeability, measured simultaneously, was relatively similar in all mammals. The species differences in erythrocytes P (urea) most probably reflect adaptation to the different types of diet and resulting different needs for concentrating urea in the urine.

Effects of triethyl phosphate and nitrate on electrokinetically enhanced biodegradation of diesel in low permeability soils.

PubMed

Lee, G T; Ro, H M; Lee, S M

2007-08-01

Bench-scale experiments for electrokinetically enhanced bioremediation of diesel in low permeability soils were conducted. An electrokinetic reactor (ER) was filled with kaolin that was artificially contaminated with diesel at a level of 2500 mg kg(-1). A constant voltage gradient of 1.0 V cm(-1) was applied. In phosphorus transport experiments, KH2PO4 was not distributed homogeneously along the ER, and most of the transported phosphorus was converted to water-insoluble aluminum phosphate after 12 days of electrokinetic (EK) operation. However, the advancing P front of triethyl phosphate (TEP) progressed with time and resulted in uniform P distribution. The treatments employed in the electrokinetically enhanced bioremediation of diesel were control (no addition of nitrogen and phosphorus), NP (KNO3+ KH2PO4), NT (KNO3+ TEP), UP (urea+ KH2PO4), and UT (urea+TEP). Analysis of effluent collected during the first 12 days of EK operation showed that diesel was not removed from the kaolin. After nutrient delivery, using the EK operation, the ER was transferred into an incubator for the biodegradation process. After 60 days of biodegradation, the concentrations of diesel in the kaolin for the NP, NT, UP, UT, and control treatments were 1356, 1002, 1658, 1612, and 2003 mg kg(-1), respectively. The ratio of biodegraded diesel concentration to initial concentration (2465 mg kg(-1)) in NP, NT, UP, UT, and control were 45.0%, 59.4%, 32.7%, 34.6%, and 18.7%, respectively. This result showed that TEP, treated along with NO3-, was most effective for the biodegradation of diesel. TEP was delivered more efficiently to the target zones and with less phosphorus loss than KH2PO4. However, this facilitated phosphorus delivery was effective in biodegrading diesel under anaerobic conditions only when electron acceptors, such as NO3-, were present.

Physiological insights into novel therapies for nephrogenic diabetes insipidus.

PubMed

Sands, Jeff M; Klein, Janet D

2016-12-01

Fundamental kidney physiology research can provide important insight into how the kidney works and suggest novel therapeutic opportunities to treat human diseases. This is especially true for nephrogenic diabetes insipidus (NDI). Over the past decade, studies elucidating the molecular physiology and signaling pathways regulating water transport have suggested novel therapeutic possibilities. In patients with congenital NDI due to mutations in the type 2 vasopressin receptor (V2R) or acquired NDI due to lithium (or other medications), there are no functional abnormalities in the aquaporin-2 (AQP2) water channel, or in another key inner medullary transport protein, the UT-A1 urea transporter. If it is possible to phosphorylate and/or increase the apical membrane accumulation of these proteins, independent of vasopressin or cAMP, one may be able to treat NDI. Sildenifil (through cGMP), erlotinib, and simvastatin each stimulate AQP2 insertion into the apical plasma membrane. Some recent human data suggest that sildenafil and simvastatin may improve urine concentrating ability. ONO-AE1-329 (ONO) stimulates the EP4 prostanoid receptor (EP4), which stimulates kinases that in turn phosphorylate AQP2 and UT-A1. Clopidogrel is a P2Y12-R antagonist that potentiates the effect of vasopressin and increases AQP2 abundance. Metformin stimulates AMPK to phosphorylate and activate AQP2 and UT-A1, and it increases urine concentrating ability in two rodent models of NDI. Since metformin, sildenafil, and simvastatin are commercially available and have excellent safety records, the potential for rapidly advancing them into clinical trials is high. Copyright © 2016 the American Physiological Society.

Physiological insights into novel therapies for nephrogenic diabetes insipidus

PubMed Central

2016-01-01

Fundamental kidney physiology research can provide important insight into how the kidney works and suggest novel therapeutic opportunities to treat human diseases. This is especially true for nephrogenic diabetes insipidus (NDI). Over the past decade, studies elucidating the molecular physiology and signaling pathways regulating water transport have suggested novel therapeutic possibilities. In patients with congenital NDI due to mutations in the type 2 vasopressin receptor (V2R) or acquired NDI due to lithium (or other medications), there are no functional abnormalities in the aquaporin-2 (AQP2) water channel, or in another key inner medullary transport protein, the UT-A1 urea transporter. If it is possible to phosphorylate and/or increase the apical membrane accumulation of these proteins, independent of vasopressin or cAMP, one may be able to treat NDI. Sildenifil (through cGMP), erlotinib, and simvastatin each stimulate AQP2 insertion into the apical plasma membrane. Some recent human data suggest that sildenafil and simvastatin may improve urine concentrating ability. ONO-AE1-329 (ONO) stimulates the EP4 prostanoid receptor (EP4), which stimulates kinases that in turn phosphorylate AQP2 and UT-A1. Clopidogrel is a P2Y12-R antagonist that potentiates the effect of vasopressin and increases AQP2 abundance. Metformin stimulates AMPK to phosphorylate and activate AQP2 and UT-A1, and it increases urine concentrating ability in two rodent models of NDI. Since metformin, sildenafil, and simvastatin are commercially available and have excellent safety records, the potential for rapidly advancing them into clinical trials is high. PMID:27534996

Potential of Mean Force Calculations of Solute Permeation Across UT-B and AQP1: A Comparison between Molecular Dynamics and 3D-RISM.

PubMed

Ariz-Extreme, Igor; Hub, Jochen S

2017-02-23

Membrane channels facilitate the efficient and selective flux of various solutes across biological membranes. A common approach to investigate the selectivity of a channel has been the calculation of potentials of mean force (PMFs) for solute permeation across the pore. PMFs have been frequently computed from molecular dynamics (MD) simulations, yet the three-dimensional reference interaction site model (3D-RISM) has been suggested as a computationally efficient alternative to MD. Whether the two methods yield comparable PMFs for solute permeation has remained unclear. In this study, we calculated potentials of mean force for water, ammonia, urea, molecular oxygen, and methanol across the urea transporter B (UT-B) and aquaporin-1 (AQP1), using 3D-RISM, as well as using MD simulations and umbrella sampling. To allow direct comparison between the PMFs from 3D-RISM and MD, we ensure that all PMFs refer to a well-defined reference area in the bulk or, equivalently, to a well-defined density of channels in the membrane. For PMFs of water permeation, we found reasonable agreement between the two methods, with differences of ≲3 kJ mol -1 . In contrast, we found stark discrepancies for the PMFs for all other solutes. Additional calculations confirm that discrepancies between MD and 3D-RISM are not explained by the choice for the closure relation, the definition the reaction coordinate (center of mass-based versus atomic site-based), details of the molecule force field, or fluctuations of the protein. Comparison of the PMFs suggests that 3D-RISM may underestimate effects from hydrophobic solute-channel interactions, thereby, for instance, missing the urea binding sites in UT-B. Furthermore, we speculate that the orientational averages inherent to 3D-RISM might lead to discrepancies in the narrow channel lumen. These findings suggest that current 3D-RISM solvers provide reasonable estimates for the PMF for water permeation, but that they are not suitable to study the selectivity of membrane channels with respect to uncharged nonwater solutes.

European genome-wide association study identifies SLC14A1 as a new urinary bladder cancer susceptibility gene

PubMed Central

Rafnar, Thorunn; Vermeulen, Sita H.; Sulem, Patrick; Thorleifsson, Gudmar; Aben, Katja K.; Witjes, J. Alfred; Grotenhuis, Anne J.; Verhaegh, Gerald W.; Hulsbergen-van de Kaa, Christina A.; Besenbacher, Soren; Gudbjartsson, Daniel; Stacey, Simon N.; Gudmundsson, Julius; Johannsdottir, Hrefna; Bjarnason, Hjordis; Zanon, Carlo; Helgadottir, Hafdis; Jonasson, Jon Gunnlaugur; Tryggvadottir, Laufey; Jonsson, Eirikur; Geirsson, Gudmundur; Nikulasson, Sigfus; Petursdottir, Vigdis; Bishop, D. Timothy; Chung-Sak, Sei; Choudhury, Ananya; Elliott, Faye; Barrett, Jennifer H.; Knowles, Margaret A.; de Verdier, Petra J.; Ryk, Charlotta; Lindblom, Annika; Rudnai, Peter; Gurzau, Eugene; Koppova, Kvetoslava; Vineis, Paolo; Polidoro, Silvia; Guarrera, Simonetta; Sacerdote, Carlotta; Panadero, Angeles; Sanz-Velez, José I.; Sanchez, Manuel; Valdivia, Gabriel; Garcia-Prats, Maria D.; Hengstler, Jan G.; Selinski, Silvia; Gerullis, Holger; Ovsiannikov, Daniel; Khezri, Abdolaziz; Aminsharifi, Alireza; Malekzadeh, Mahyar; van den Berg, Leonard H.; Ophoff, Roel A.; Veldink, Jan H.; Zeegers, Maurice P.; Kellen, Eliane; Fostinelli, Jacopo; Andreoli, Daniele; Arici, Cecilia; Porru, Stefano; Buntinx, Frank; Ghaderi, Abbas; Golka, Klaus; Mayordomo, José I.; Matullo, Giuseppe; Kumar, Rajiv; Steineck, Gunnar; Kiltie, Anne E.; Kong, Augustine; Thorsteinsdottir, Unnur; Stefansson, Kari; Kiemeney, Lambertus A.

2011-01-01

Three genome-wide association studies in Europe and the USA have reported eight urinary bladder cancer (UBC) susceptibility loci. Using extended case and control series and 1000 Genomes imputations of 5 340 737 single-nucleotide polymorphisms (SNPs), we searched for additional loci in the European GWAS. The discovery sample set consisted of 1631 cases and 3822 controls from the Netherlands and 603 cases and 37 781 controls from Iceland. For follow-up, we used 3790 cases and 7507 controls from 13 sample sets of European and Iranian ancestry. Based on the discovery analysis, we followed up signals in the urea transporter (UT) gene SLC14A. The strongest signal at this locus was represented by a SNP in intron 3, rs17674580, that reached genome-wide significance in the overall analysis of the discovery and follow-up groups: odds ratio = 1.17, P = 7.6 × 10−11. SLC14A1 codes for UTs that define the Kidd blood group and are crucial for the maintenance of a constant urea concentration gradient in the renal medulla and, through this, the kidney's ability to concentrate urine. It is speculated that rs17674580, or other sequence variants in LD with it, indirectly modifies UBC risk by affecting urine production. If confirmed, this would support the ‘urogenous contact hypothesis’ that urine production and voiding frequency modify the risk of UBC. PMID:21750109

Absence of PKC-Alpha Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus

PubMed Central

Sim, Jae H.; Himmel, Nathaniel J.; Redd, Sara K.; Pulous, Fadi E.; Rogers, Richard T.; Black, Lauren N.; Hong, Seongun M.; von Bergen, Tobias N.; Blount, Mitsi A.

2014-01-01

Lithium, an effective antipsychotic, induces nephrogenic diabetes insipidus (NDI) in ∼40% of patients. The decreased capacity to concentrate urine is likely due to lithium acutely disrupting the cAMP pathway and chronically reducing urea transporter (UT-A1) and water channel (AQP2) expression in the inner medulla. Targeting an alternative signaling pathway, such as PKC-mediated signaling, may be an effective method of treating lithium-induced polyuria. PKC-alpha null mice (PKCα KO) and strain-matched wild type (WT) controls were treated with lithium for 0, 3 or 5 days. WT mice had increased urine output and lowered urine osmolality after 3 and 5 days of treatment whereas PKCα KO mice had no change in urine output or concentration. Western blot analysis revealed that AQP2 expression in medullary tissues was lowered after 3 and 5 days in WT mice; however, AQP2 was unchanged in PKCα KO. Similar results were observed with UT-A1 expression. Animals were also treated with lithium for 6 weeks. Lithium-treated WT mice had 19-fold increased urine output whereas treated PKCα KO animals had a 4-fold increase in output. AQP2 and UT-A1 expression was lowered in 6 week lithium-treated WT animals whereas in treated PKCα KO mice, AQP2 was only reduced by 2-fold and UT-A1 expression was unaffected. Urinary sodium, potassium and calcium were elevated in lithium-fed WT but not in lithium-fed PKCα KO mice. Our data show that ablation of PKCα preserves AQP2 and UT-A1 protein expression and localization in lithium-induced NDI, and prevents the development of the severe polyuria associated with lithium therapy. PMID:25006961

Nitrogen metabolism, acid-base regulation, and molecular responses to ammonia and acid infusions in the spiny dogfish shark (Squalus acanthias).

PubMed

Nawata, C Michele; Walsh, Patrick J; Wood, Chris M

2015-07-01

Although they are ureotelic, marine elasmobranchs express Rh glycoproteins, putative ammonia channels. To address questions raised by a recent study on high environmental ammonia (HEA) exposure, dogfish were intravascularly infused for 24 h at 3 ml kg(-1) h(-1) with isosmotic NaCl (500 mmol l(-1), control), NH4HCO3 (500 mmol l(-1)), NH4Cl (500 mmol l(-1)), or HCl (as 125 mmol l(-1) HCl + 375 mmol l(-1) NaCl). While NaCl had no effect on arterial acid-base status, NH4HCO3 caused mild alkalosis, NH4Cl caused strong acidosis, and HCl caused lesser acidosis, all predominantly metabolic in nature. Total plasma ammonia (T(Amm)) and excretion rates of ammonia (J(Amm)) and urea-N (J(Urea-N)) were unaffected by NaCl or HCl. However, despite equal loading rates, plasma T(Amm) increased to a greater extent with NH4Cl, while J(Amm) increased to a greater extent with NH4HCO3 due to much greater increases in blood-to-water PNH3 gradients. As with HEA, both treatments caused large (90%) elevations of J(Urea-N), indicating that urea-N synthesis by the ornithine-urea cycle (OUC) is driven primarily by ammonia rather than HCO3(-). Branchial mRNA expressions of Rhbg and Rhp2 were unaffected by NH4HCO3 or NH4Cl, but v-type H(+)-ATPase was down-regulated by both treatments, and Rhbg and Na(+)/H(+) exchanger NHE2 were up-regulated by HCl. In the kidney, Rhbg was unresponsive to all treatments, but Rhp2 was up-regulated by HCl, and the urea transporter UT was up-regulated by HCl and NH4Cl. These responses are discussed in the context of current ideas about branchial, renal, and OUC function in this nitrogen-limited predator.

Characterization of urea transport in Bufo arenarum oocytes.

PubMed

Silberstein, Claudia; Zotta, Elsa; Ripoche, Pierre; Ibarra, Cristina

2003-07-01

Xenopus laevis oocytes have been extensively used for expression cloning, structure/function relationships, and regulation analysis of transporter proteins. Urea transporters have been expressed in Xenopus oocytes and their properties have been described. In order to establish an alternative system in which urea transporters could be efficiently expressed and studied, we determined the urea transport properties of ovarian oocytes from Bufo arenarum, a toad species common in Argentina. Bufo oocytes presented a high urea permeability of 22.3 x 10(-6) cm/s, which was significantly inhibited by the incubation with phloretin. The urea uptake in these oocytes was also inhibited by mercurial reagents, and high-affinity urea analogues. The urea uptake was not sodium dependent. The activation energy was 3.2 Kcal/mol, suggesting that urea movement across membrane oocytes may be through a facilitated urea transporter. In contrast, Bufo oocytes showed a low permeability for mannitol and glycerol. From these results, we propose that one or several specific urea transporters are present in ovarian oocytes from Bufo arenarum. Therefore, these oocytes cannot be used in expression studies of foreign urea transporters. The importance of Bufo urea transporter is not known but could be implicated in osmotic regulation during the laying of eggs in water. Copyright 2003 Wiley-Liss, Inc.

Definition of high-performance membranes - from the clinical point of view.

PubMed

Saito, Akira

2011-01-01

Global knowledge of the molecular target of uremic toxins (UTs) was significantly different in the 1980s than it is now. In 1971, Babb et al. hypothesized that UTs such as neurotoxin existed in mid-sized molecules ranging from 300 to 3,000 Da. In the 1980s, larger molecular weight substances > 5,000 Da were targeted for removal, as well as small and medium size toxins in Japan, while urea was considered a surrogate marker of UTs, and Kt/V for urea was used as a measure of dialysis dose in the USA. In Japan, albumin-bound toxins in addition to low-molecular-weight proteins were targeted for removal as glomerular filtration in the normal kidney. As binding capacity of albumin is significantly lowered and, on the other hand, the α-helical content of albumin also lowered in uremic patients because of binding of UTs to albumin, a small amount of albumin should be removed to stimulate the synthesis of new albumin. KF101 C-2 (EVAL) used as a high-performance dialysis membrane (HPM) at the first step, in which approximately 7 g of albumin is removed per dialysis session. It resulted in lowered plasma albumin levels in hemodialysis patients, although accumulated levels of low-molecular-weight proteins were significantly lowered. Therefore, the Japanese Society of Dialysis Therapy has recommended limitation of albumin removal to < 3 g/session by the second generation of HPMs. Many different HPMs have been developed since the Japanese Society of HPM was first organized in 1985. Approximately 98% of the dialyzers used in Japan employ HPMs. New technology is required to suppress fouling on the surface and in the pores of HPMs. This would maintain permeation of inflammatory cytokines during dialysis sessions. Copyright © 2011 S. Karger AG, Basel.

Urea transporter knockout mice and their renal phenotypes.

PubMed

Fenton, Robert A; Yang, Baoxue

2014-01-01

Urea transporter gene knockout mice have been created for the study of the urine-concentrating mechanism. The major findings in studies of the renal phenotype of these mice are as follows: (1) Urea accumulation in the inner medullary interstitium is dependent on intrarenal urea recycling mediated by urea transporters; (2) urea transporters are essential for preventing urea-induced osmotic diuresis and thus for water conservation; (3) NaCl concentration in the inner medullary interstitium is not significantly affected by the absence of IMCD, descending limb of Henle and descending vasa recta urea transporters. Studies in urea transporter knockout mouse models have highlighted the essential role of urea for producing maximally concentrated urine.

CsNIP2;1 is a Plasma Membrane Transporter from Cucumis sativus that Facilitates Urea Uptake When Expressed in Saccharomyces cerevisiae and Arabidopsis thaliana.

PubMed

Zhang, Lu; Yan, Jiapei; Vatamaniuk, Olena K; Du, Xiangge

2016-03-01

Urea is an important source of nitrogen (N) for the growth and development of plants. It occurs naturally in soils, is the major N source in agricultural fertilizers and is an important N metabolite in plants. Therefore, the identification and characterization of urea transporters in higher plants is important for the fundamental understanding of urea-based N nutrition in plants and for designing novel strategies for improving the N-use efficiency of urea based-fertilizers. Progress in this area, however, is hampered due to scarce knowledge of plant urea transporters. From what is known, urea uptake from the soil into plant roots is mediated by two types of transporters: the major intrinsic proteins (MIPs) and the DUR3 orthologs, mediating low- and high-affinity urea transport, respectively. Here we characterized a MIP family member from Cucumis sativus, CsNIP2;1, with regard to its contribution to urea transport. We show that CsNIP2;1 is a plasma membrane transporter that mediates pH-dependent urea uptake when expressed in yeast. We also found that ectopic expression of CsNIP2;1 improves growth of wild-type Arabidopsis thaliana and rescues growth and development of the atdur3-3 mutant on medium with urea as the sole N source. In addition, CsNIP2;1 is transcriptionally up-regulated by N deficiency, urea and NO3 (-). These data and results from the analyses of the pattern of CsNIP2;1 expression in A. thaliana and cucumber suggest that CsNIP2;1 might be involved in multiple steps of urea-based N nutrition, including urea uptake and internal transport during N remobilization throughout seed germination and N delivery to developing tissues. © Crown copyright 2016.

Sildenafil reduces polyuria in rats with lithium-induced NDI.

PubMed

Sanches, Talita Rojas; Volpini, Rildo Aparecido; Massola Shimizu, Maria H; Bragança, Ana Carolina de; Oshiro-Monreal, Fabíola; Seguro, Antonio Carlos; Andrade, Lúcia

2012-01-01

Lithium (Li)-treated patients often develop urinary concentrating defect and polyuria, a condition known as nephrogenic diabetes insipidus (NDI). In a rat model of Li-induced NDI, we studied the effect that sildenafil (Sil), a phosphodiesterase 5 (PDE5) inhibitor, has on renal expression of aquaporin-2 (AQP2), urea transporter UT-A1, Na(+)/H(+) exchanger 3 (NHE3), Na(+)-K(+)-2Cl(-) cotransporter (NKCC2), epithelial Na channel (ENaC; α-, β-, and γ-subunits), endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase. We also evaluated cGMP levels in medullary collecting duct cells in suspension. For 4 wk, Wistar rats received Li (40 mmol/kg food) or no treatment (control), some receiving, in weeks 2-4, Sil (200 mg/kg food) or Li and Sil (Li+Sil). In Li+Sil rats, urine output and free water clearance were markedly lower, whereas urinary osmolality was higher, than in Li rats. The cGMP levels in the suspensions of medullary collecting duct cells were markedly higher in the Li+Sil and Sil groups than in the control and Li groups. Semiquantitative immunoblotting revealed the following: in Li+Sil rats, AQP2 expression was partially normalized, whereas that of UT-A1, γ-ENaC, and eNOS was completely normalized; and expression of NKCC2 and NHE3 was significantly higher in Li rats than in controls. Inulin clearance was normal in all groups. Mean arterial pressure and plasma arginine vasopressin did not differ among the groups. Sil completely reversed the Li-induced increase in renal vascular resistance. We conclude that, in experimental Li-induced NDI, Sil reduces polyuria, increases urinary osmolality, and decreases free water clearance via upregulation of renal AQP2 and UT-A1.

Utilization of urea and expression profiles of related genes in the dinoflagellate Prorocentrum donghaiense

PubMed Central

Jing, Xiaoli; Lin, Senjie; Zhang, Huan; Koerting, Claudia; Yu, Zhigang

2017-01-01

Urea has been shown to contribute more than half of total nitrogen (N) required by phytoplankton in some estuaries and coastal waters and to provide a substantial portion of the N demand for many harmful algal blooms (HABs) of dinoflagellates. In this study, we investigated the physiological and transcriptional responses in Prorocentrum donghaiense to changes in nitrate and urea availability. We found that this species could efficiently utilize urea as sole N source and achieve comparable growth rate and photosynthesis capability as it did under nitrate. These physiological parameters were markedly lower in cultures grown under nitrate- or urea-limited conditions. P. donghaiense N content was similarly low under nitrate- or urea-limited culture condition, but was markedly higher under urea-replete condition than under nitrate-replete condition. Carbon (C) content was consistently elevated under N-limited condition. Consequently, the C:N ratio was as high as 21:1 under nitrate- or urea-limitation, but 7:1 under urea-replete condition and 9:1 to 10:1 under nitrate-replete condition. Using quantitative reverse transcription PCR, we investigated the expression pattern for four genes involved in N transport and assimilation. The results indicated that genes encoding nitrate transport, urea hydrolysis, and nickel transporter gene were sensitive to changes in general N nutrient availability whereas the urea transporter gene responded much more strongly to changes in urea concentration. Taken together, our study shows the high bioavailability of urea, its impact on C:N stoichiometry, and the sensitivity of urea transporter gene expression to urea availability. PMID:29117255

Utilization of urea and expression profiles of related genes in the dinoflagellate Prorocentrum donghaiense.

PubMed

Jing, Xiaoli; Lin, Senjie; Zhang, Huan; Koerting, Claudia; Yu, Zhigang

2017-01-01

Urea has been shown to contribute more than half of total nitrogen (N) required by phytoplankton in some estuaries and coastal waters and to provide a substantial portion of the N demand for many harmful algal blooms (HABs) of dinoflagellates. In this study, we investigated the physiological and transcriptional responses in Prorocentrum donghaiense to changes in nitrate and urea availability. We found that this species could efficiently utilize urea as sole N source and achieve comparable growth rate and photosynthesis capability as it did under nitrate. These physiological parameters were markedly lower in cultures grown under nitrate- or urea-limited conditions. P. donghaiense N content was similarly low under nitrate- or urea-limited culture condition, but was markedly higher under urea-replete condition than under nitrate-replete condition. Carbon (C) content was consistently elevated under N-limited condition. Consequently, the C:N ratio was as high as 21:1 under nitrate- or urea-limitation, but 7:1 under urea-replete condition and 9:1 to 10:1 under nitrate-replete condition. Using quantitative reverse transcription PCR, we investigated the expression pattern for four genes involved in N transport and assimilation. The results indicated that genes encoding nitrate transport, urea hydrolysis, and nickel transporter gene were sensitive to changes in general N nutrient availability whereas the urea transporter gene responded much more strongly to changes in urea concentration. Taken together, our study shows the high bioavailability of urea, its impact on C:N stoichiometry, and the sensitivity of urea transporter gene expression to urea availability.

75 FR 22892 - Environmental Impact Statement: Salt Lake County, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... Lake County, UT AGENCY: Federal Highway Administration (FHWA), USDOT. ACTION: Notice of Intent. SUMMARY... be prepared for a proposed transportation improvement project in Salt Lake County, Utah. FOR FURTHER... 4700 South, Suite 9A, Salt Lake City, UT 84118, telephone (801) 963-0182, e-mail [email protected

75 FR 9476 - Environmental Impact Statement: Salt Lake County, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-02

... Lake County, UT AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice of intent. SUMMARY... be prepared for a proposed transportation improvement project in Salt Lake County, Utah. FOR FURTHER... 9A, Salt Lake City, UT 84118, Telephone: (801) 963-0182, E-mail: [email protected] . The Utah...

Transepithelial water and urea permeabilities of isolated perfused Munich-Wistar rat inner medullary thin limbs of Henle's loop.

PubMed

Nawata, C Michele; Evans, Kristen K; Dantzler, William H; Pannabecker, Thomas L

2014-01-01

To better understand the role that water and urea fluxes play in the urine concentrating mechanism, we determined transepithelial osmotic water permeability (Pf) and urea permeability (Purea) in isolated perfused Munich-Wistar rat long-loop descending thin limbs (DTLs) and ascending thin limbs (ATLs). Thin limbs were isolated either from 0.5 to 2.5 mm below the outer medulla (upper inner medulla) or from the terminal 2.5 mm of the inner medulla. Segment types were characterized on the basis of structural features and gene expression levels of the water channel aquaporin 1, which was high in the upper DTL (DTLupper), absent in the lower DTL (DTLlower), and absent in ATLs, and the Cl-(1) channel ClCK1, which was absent in DTLs and high in ATLs. DTLupper Pf was high (3,204.5 ± 450.3 μm/s), whereas DTLlower showed very little or no osmotic Pf (207.8 ± 241.3 μm/s). Munich-Wistar rat ATLs have previously been shown to exhibit no Pf. DTLupper Purea was 40.0 ± 7.3 × 10(-5) cm/s and much higher in DTLlower (203.8 ± 30.3 × 10(-5) cm/s), upper ATL (203.8 ± 35.7 × 10(-5) cm/s), and lower ATL (265.1 ± 49.8 × 10(-5) cm/s). Phloretin (0.25 mM) did not reduce DTLupper Purea, suggesting that Purea is not due to urea transporter UT-A2, which is expressed in short-loop DTLs and short portions of some inner medullary DTLs close to the outer medulla. In summary, Purea is similar in all segments having no osmotic Pf but is significantly lower in DTLupper, a segment having high osmotic Pf. These data are inconsistent with the passive mechanism as originally proposed.

Causes of high O3 in the lower free troposphere over the Pacific Northwest as observed at the Mt. Bachelor Observatory

NASA Astrophysics Data System (ADS)

Ambrose, J. L.; Reidmiller, D. R.; Jaffe, D. A.

2011-09-01

We measured O3, CO, Hg, sub-micron particle scattering of mid-visible light (σsp), and water vapor (WV) at the Mt. Bachelor Observatory (MBO) in central Oregon, USA since 2004. The data were used to identify sources of large ozone enhancements in the lower free troposphere (FT). A total of 25 high-ozone events, defined as time periods when the 8-h averaged O3 mixing ratio was >70.0 ppbv, were recorded. The events occurred between early March and late September. For 18 of the 25 event days we were able to identify sources based on (1) relative enhancements of O3, CO, Hg and WV compared with the corresponding monthly distributions and (2) supporting data from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the Navy Aerosol Analysis and Prediction System (NAAPS) global aerosol model, and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived active fire counts from the Fire Information for Resource Management System (FIRMS). Our analysis suggests that enhanced O3 levels during all the identified events were transported to MBO in the FT and were driven mostly by subsidence of O3-rich air masses from the upper troposphere/lower stratosphere (UT/LS), Asian long range transport (ALRT) and mixed ALRT + UT/LS influences. The UT/LS events were depleted in CO and total atmospheric mercury (TAM) compared to monthly median values. Levels of O3 and CO tended to be anti-correlated during UT/LS events, consistent with transport from clean regions in the UT. Conversely, the ALRT events were characterized by concomitant enhancements in CO and TAM with mean values during each event that were >70th percentile values for the months during which the events occurred. Unlike for UT/LS events, levels of O3 and CO during ALRT events tended to be correlated, consistent with photochemical O3 production in polluted air masses transported across the Pacific. The mixed ALRT + UT/LS events exhibited characteristics that were intermediate between those of the ALRT and UT/LS events. For the classifiable cases the fractional distribution of each event type was: UT/LS, ˜44% (n = 8); ALRT + UT/LS, ˜33% (n = 6); ALRT, ˜22% (n = 4). In terms of the total number of classifiable high-ozone event hours UT/LS, ALRT + UT/LS and ALRT events accounted for ˜52% (t = 85), ˜36% (t = 59) and ˜13% (t = 21), respectively. The results indicate that downward mixing of O3-rich air masses from the UT/LS together with trans-Pacific transport of urban/industrial and biomass burning emissions from the Asian continent are the most important mechanisms for delivering high O3 levels (i.e., 8-h averages >70.0 ppbv) to the lower FT in the Pacific Northwest.

Active urea transport in lower vertebrates and mammals.

PubMed

Bankir, Lise

2014-01-01

Some unicellular organisms can take up urea from the surrounding fluids by an uphill pumping mechanism. Several active (energy-dependent) urea transporters (AUTs) have been cloned in these organisms. Functional studies show that active urea transport also occurs in elasmobranchs, amphibians, and mammals. In the two former groups, active urea transport may serve to conserve urea in body fluids in order to balance external high ambient osmolarity or prevent desiccation. In mammals, active urea transport may be associated with the need to either store and/or reuse nitrogen in the case of low nitrogen supply, or to excrete nitrogen efficiently in the case of excess nitrogen intake. There are probably two different families of AUTs, one with a high capacity able to establish only a relatively modest transepithelial concentration difference (renal tubule of some frogs, pars recta of the mammalian kidney, early inner medullary collecting duct in some mammals eating protein-poor diets) and others with a low capacity but able to maintain a high transepithelial concentration difference that has been created by another mechanism or in another organ (elasmobranch gills, ventral skin of some toads, and maybe mammalian urinary bladder). Functional characterization of these transporters shows that some are coupled to sodium (symports or antiports) while others are sodium-independent. In humans, only one genetic anomaly, with a mild phenotype (familial azotemia), is suspected to concern one of these transporters. In spite of abundant functional evidence for such transporters in higher organisms, none have been molecularly identified yet.

Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion.

PubMed

Weiner, I David; Mitch, William E; Sands, Jeff M

2015-08-07

Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. Copyright © 2015 by the American Society of Nephrology.

Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion

PubMed Central

Mitch, William E.; Sands, Jeff M.

2015-01-01

Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. PMID:25078422

Causes of high O3 in the lower free troposphere over the Pacific Northwest as observed at the Mt. Bachelor Observatory

NASA Astrophysics Data System (ADS)

Ambrose, J. L.; Reidmiller, D.; Jaffe, D. A.

2011-12-01

We measured O3, CO, Hg, sub-micron particle scattering of mid-visible light (σsp), and water vapor (WV) at the Mt. Bachelor Observatory (MBO) in central Oregon, USA since 2004. The data were used to identify sources of large ozone enhancements in the lower free troposphere (FT) from 2004-2009. A total of 25 high-ozone events, defined as time periods when the 8-hr averaged O3 mixing ratio was >70.0 ppbv, were recorded. The events occurred between early March and late September. For 18 of the 25 event days we were able to identify sources based on (1) relative enhancements of O3, CO, Hg and WV compared with the corresponding monthly distributions and (2) supporting data from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the Navy Aerosol Analysis and Prediction System (NAAPS) global aerosol model, and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived active fire counts from the Fire Information for Resource Management System (FIRMS). Our analysis suggests that enhanced O3 levels during all the identified events were transported to MBO in the FT and were driven mostly by subsidence of O3-rich air masses from the upper troposphere/lower stratosphere (UT/LS), Asian long range transport (ALRT) and mixed ALRT+UT/LS influences. The UT/LS events were depleted in CO and total atmospheric mercury (TAM) compared to monthly median values. Levels of O3 and CO tended to be anti-correlated during UT/LS events, consistent with transport from clean regions in the UT. Conversely, the ALRT events were characterized by concomitant enhancements in CO and TAM with mean values during each event that were >70th percentile values for the months during which the events occurred. Unlike for UT/LS events, levels of O3 and CO during ALRT events tended to be correlated, consistent with photochemical O3 production in polluted air masses transported across the Pacific. The mixed ALRT+UT/LS events exhibited characteristics that were intermediate between those of the ALRT and UT/LS events. For the classifiable cases the fractional distribution of each event type was: UT/LS, ~44% (n=8); ALRT+UT/LS, ~33% (n=6); ALRT, ~22% (n=4). In terms of the total number of classifiable high-ozone event hours UT/LS, ALRT+UT/LS and ALRT events accounted for ~52% (t=85), ~36% (t=59) and ~13% (t=21), respectively. The results indicate that downward mixing of O3-rich air masses from the UT/LS together with trans-Pacific transport of urban/industrial and biomass burning emissions from the Asian continent are the most important mechanisms for delivering high O3 levels (i.e., 8-hr averages >70.0 ppbv) to the lower FT in the Pacific Northwest. The high-ozone event characterization methodology developed from the 2004-2009 data set is further applied to observations made at MBO during 2010 and 2011.

Modelling and mutational analysis of Aspergillus nidulans UreA, a member of the subfamily of urea/H+ transporters in fungi and plants

PubMed Central

Sanguinetti, Manuel; Amillis, Sotiris; Pantano, Sergio; Scazzocchio, Claudio; Ramón, Ana

2014-01-01

We present the first account of the structure–function relationships of a protein of the subfamily of urea/H+ membrane transporters of fungi and plants, using Aspergillus nidulans UreA as a study model. Based on the crystal structures of the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT) and of the Nucleobase-Cation-Symport-1 benzylhydantoin transporter from Microbacterium liquefaciens (Mhp1), we constructed a three-dimensional model of UreA which, combined with site-directed and classical random mutagenesis, led to the identification of amino acids important for UreA function. Our approach allowed us to suggest roles for these residues in the binding, recognition and translocation of urea, and in the sorting of UreA to the membrane. Residues W82, Y106, A110, T133, N275, D286, Y388, Y437 and S446, located in transmembrane helixes 2, 3, 7 and 11, were found to be involved in the binding, recognition and/or translocation of urea and the sorting of UreA to the membrane. Y106, A110, T133 and Y437 seem to play a role in substrate selectivity, while S446 is necessary for proper sorting of UreA to the membrane. Other amino acids identified by random classical mutagenesis (G99, R141, A163, G168 and P639) may be important for the basic transporter's structure, its proper folding or its correct traffic to the membrane. PMID:24966243

1,[Formula: see text]2,[Formula: see text]3,[Formula: see text]4,[Formula: see text]6-Penta-O-Galloyl-β-D-Glucose from Galla rhois Ameliorates Renal Tubular Injury and Microvascular Inflammation in Acute Kidney Injury Rats.

PubMed

Park, Ji Hun; Kho, Min Chol; Oh, Hyun Cheol; Kim, Youn Chul; Yoon, Jung Joo; Lee, Yun Jung; Kang, Dae Gill; Lee, Ho Sub

2018-05-13

Renal ischemia-reperfusion injury (IRI), an important cause of acute kidney injury (AKI), causes increased renal tubular injury and microvascular inflammation. 1,[Formula: see text]2,[Formula: see text]3,[Formula: see text]4,[Formula: see text]6-penta-O-galloyl-[Formula: see text]-D-glucose (PGG) from Galla rhois has anticancer, anti-oxidation and angiogenesis effects. We examined protective effects of PGG on IRI-induced acute AKI. Clamping both renal arteries for 45[Formula: see text]min induced isechemia and then reperfusion. Treatment with PGG (10[Formula: see text]mg/kg/day and 50[Formula: see text]mg/kg/day for four days) significantly ameliorated urine volume, urine osmolality, creatinine clearance (Ccr) and blood urea nitrogen (BUN). In addition, PGG increased aquaporine 1/2/3, Na[Formula: see text]-K[Formula: see text]-ATPase and urea transporter (UT-B) and decreased ICAM-1, MCP-1, and HMGB-1 expression. In this histopathologic study, PGG improved glomerular and tubular damage. Immunohistochemistry results showed that PGG increased aquaporine 1/2, and Na[Formula: see text]-K[Formula: see text] ATPase and decreased ICAM-1 expression. These findings suggest that PGG ameliorates tubular injury including tubular dysfunction and microvascular inflammation in IRI-induced AKI rats.

The diuretic effect of urea analog dimethylthiourea in female Wistar rats.

PubMed

Cil, O; Ertunc, M; Onur, R

2012-10-01

Urea plays an important role in the urinary concentrating mechanism in the kidney by contributing greatly in the generation of hyperosmolar medulla due to the presence of urea transporters, which mediate facilitated transport of urea. In this study, we investigated the possible diuretic effect of urea analog and urea transporter inhibitor, dimethylthiourea (DMTU), in rats. Female Wistar rats were divided into two groups, group 1 (control group, n = 7) rats were injected with saline intraperitoneally (i.p.), while group 2 (DMTU group, n = 7) rats were injected with 500 mg/kg DMTU (i.p.) and an additional dose of 125 mg/kg DMTU after 8 h. DMTU administration induced an approximately three times increase in daily urine volume (p < 0.001) and decreased urine osmolality to approximately 35% of controls (p < 0.0001). DMTU also increased free water clearance (p < 0.0001) without a significant change in osmolar clearance. DMTU treatment caused an increase in urea clearance (p < 0.05) and fractional excretion of urea (p < 0.05) with a decrease in serum urea concentration (p < 0.001). DMTU had no effect on creatinine clearance or serum electrolytes, creatinine levels and osmolality. With these findings, we report for the first time that DMTU has a prominent diuretic effect with increased urea excretion, which may be explained by the inhibitory effect of the drug on urea transporters. Our findings suggest that DMTU may be used as a diuretic agent and also could be used as a lead compound for the development of novel diuretics.

Mechanisms of molecular transport through the urea channel of Helicobacter pylori

PubMed Central

McNulty, Reginald; Ulmschneider, Jakob P.; Luecke, Hartmut; Ulmschneider, Martin B.

2013-01-01

Helicobacter pylori survival in acidic environments relies on cytoplasmic hydrolysis of gastric urea into ammonia and carbon dioxide, which buffer the pathogen’s periplasm. Urea uptake is greatly enhanced and regulated by HpUreI, a proton-gated inner membrane channel protein essential for gastric survival of H. pylori. The crystal structure of HpUreI describes a static snapshot of the channel with two constriction sites near the center of the bilayer that are too narrow to allow passage of urea or even water. Here we describe the urea transport mechanism at atomic resolution, revealed by unrestrained microsecond equilibrium molecular dynamics simulations of the hexameric channel assembly. Two consecutive constrictions open to allow conduction of urea, which is guided through the channel by interplay between conserved residues that determine proton rejection and solute selectivity. Remarkably, HpUreI conducts water at rates equivalent to aquaporins, which might be essential for efficient transport of urea at small concentration gradients. PMID:24305683

Mechanisms of molecular transport through the urea channel of Helicobacter pylori

NASA Astrophysics Data System (ADS)

McNulty, Reginald; Ulmschneider, Jakob P.; Luecke, Hartmut; Ulmschneider, Martin B.

2013-12-01

Helicobacter pylori survival in acidic environments relies on cytoplasmic hydrolysis of gastric urea into ammonia and carbon dioxide, which buffer the pathogen’s periplasm. Urea uptake is greatly enhanced and regulated by HpUreI, a proton-gated inner membrane channel protein essential for gastric survival of H. pylori. The crystal structure of HpUreI describes a static snapshot of the channel with two constriction sites near the center of the bilayer that are too narrow to allow passage of urea or even water. Here we describe the urea transport mechanism at atomic resolution, revealed by unrestrained microsecond equilibrium molecular dynamics simulations of the hexameric channel assembly. Two consecutive constrictions open to allow conduction of urea, which is guided through the channel by interplay between conserved residues that determine proton rejection and solute selectivity. Remarkably, HpUreI conducts water at rates equivalent to aquaporins, which might be essential for efficient transport of urea at small concentration gradients.

Lack of association between Kidd blood group system and chronic kidney disease.

PubMed

Capriolli, Tiago Verri; Visentainer, Jeane Eliete Laguila; Sell, Ana Maria

The Kidd blood group system has three antigens, Jk a , Jk b and Jk3, found on red blood cells and on endothelial cells of the inner lining of blood vessels in the renal medulla. These are known as urea transporter B (UT-B). Researchers have found that individuals carrying the Jk(a-b-) or Jk-null (UT-B null) phenotypes have a lower urine-concentrating capability and risk of severe renal impairment. This study evaluated the distribution of the Kidd phenotypes in patients with chronic kidney disease and a possible association of Kidd antigens with the development of renal disease. Jk a and Jk b antigens were phenotyped using the gel column agglutination test (ID-cards Bio-RAD) in 197 patients with chronic kidney disease and 444 blood donors, as the control group. The phenotype and antigen frequencies between patients and controls were evaluated using the Chi-square method with Yates correction and logistic regression after adjustments for gender and age. No differences were observed between the Kidd phenotypes frequency distribution between patients with chronic kidney disease and blood donors [Jk(a-b+)=22.3% and 27.2%; Jk(a+b-)=30.5% and 24.3%; Jk(a+b+)=47.25% and 48.4%, respectively]. The distribution of Kidd phenotypes found in the studied population is expected for Caucasians; Jk a and Jk b antigens and phenotypes were not found to be related to susceptibility for chronic kidney disease. Copyright © 2017 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda. All rights reserved.

Mathematical modeling of urea transport in the kidney.

PubMed

Layton, Anita T

2014-01-01

Mathematical modeling techniques have been useful in providing insights into biological systems, including the kidney. This article considers some of the mathematical models that concern urea transport in the kidney. Modeling simulations have been conducted to investigate, in the context of urea cycling and urine concentration, the effects of hypothetical active urea secretion into pars recta. Simulation results suggest that active urea secretion induces a "urea-selective" improvement in urine concentrating ability. Mathematical models have also been built to study the implications of the highly structured organization of tubules and vessels in the renal medulla on urea sequestration and cycling. The goal of this article is to show how physiological problems can be formulated and studied mathematically, and how such models may provide insights into renal functions.

21 CFR 176.320 - Sodium nitrate-urea complex.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrate-urea complex. 176.320 Section 176... Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a..., packaging, transporting, or holding food, subject to the provisions of this section. (a) Sodium nitrate-urea...

Connecting Surface Emissions, Convective Uplifting, and Long-Range Transport of Carbon Monoxide in the Upper Troposphere: New Observations from the Aura Microwave Limb Sounder

NASA Technical Reports Server (NTRS)

Jiang, Jonathan H.; Livesey, Nathaniel J.; Su, Hui; Neary, Lori; McConnell, John C.; Richards, Nigel A. D.

2007-01-01

Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed; in combination with the CO surface emission climatology and data from the NCEP analyses. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality.

Sources of enhanced SO2 in the tropical Western Pacific UT/LS

NASA Astrophysics Data System (ADS)

Rollins, A. W.; Thornberry, T. D.; Liu, S.; Ray, E. A.; Atlas, E. L.; Navarro, M. A.; Schauffler, S.; Bui, T. V.; Gao, R. S.

2017-12-01

Sulfur dioxide is an important precursor to aerosols in the stratosphere. Typical mixing ratios of SO2 in the tropical upper troposphere and lower stratosphere (UT/LS) are on the order of a few pptv. Convective transport of SO2 from source regions near the surface can produce local enhancements in the UT/LS of more than one order of magnitude compared to typical values. These local enhancements if sufficient in number and/or magnitude might be important for the stratospheric aerosol budget. Here we analyze three such local enhancements observed during the NASA POSIDON mission. We use back-trajectories and tracer species to demonstrate that significant SO2 in the UT/LS on different occasions originated from 1) a volcano in Papua New Guinea, 2) convection over Asia, and 3) transport of air by a typhoon. These examples that were observed on three out of ten flights indicate that significant SO2 over the Western Pacific is not uncommon, and may be an important fraction of the stratospheric aerosol budget.

Diabetes induced renal urea transport alterations assessed with 3D hyperpolarized 13 C,15 N-Urea.

PubMed

Bertelsen, Lotte B; Nielsen, Per M; Qi, Haiyun; Nørlinger, Thomas S; Zhang, Xiaolu; Stødkilde-Jørgensen, Hans; Laustsen, Christoffer

2017-04-01

In the current study, we investigated hyperpolarized urea as a possible imaging biomarker of the renal function by means of the intrarenal osmolality gradient. Hyperpolarized three-dimensional balanced steady state 13 C MRI experiments alongside kidney function parameters and quantitative polymerase chain reaction measurements was performed on two groups of rats, a streptozotocin type 1 diabetic group and a healthy control group. A significant decline in intrarenal steepness of the urea gradient was found after 4 weeks of untreated insulinopenic diabetes in agreement with an increased urea transport transcription. MRI and hyperpolarized [ 13 C, 15 N]urea can monitor the changes in the corticomedullary urea concentration gradients in diabetic and healthy control rats. Magn Reson Med 77:1650-1655, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Chemical Tracers as an Indicator of Transport in the UT/LS

NASA Astrophysics Data System (ADS)

Moore, F. L.; Hurst, D. F.; Elkins, J. W.; Nance, J. D.; Dutton, G. S.; Hall, B. D.

2009-12-01

Previous airborne studies have proven the scientific value of chemical tracers in examining transport of the Upper Troposphere and Lower Stratosphere (UT/LS). ESRL scientists operated two airborne gas chromatographs on the NCAR G-V during the NSF sponsored Stratosphere-Troposphere Analyses of Regional Transport START-08 campaign over the midlatitudes of central North America. The Unmanned aircraft systems Chromatograph for Atmospheric Trace Species (UCATS) is comprised of a two-channel electron capture detection-gas chromatograph (ECD-GC), an ozone absorption photometer, and a water vapor tunable diode laser spectrometer. It measures N2O and SF6 every 70 seconds on one EC-GC channel, and H2, CO, and CH4 every 140 seconds on the second channel. PAN and Trace Hydrohalocarbon ExpeRiment (PANTHER) is a six-channel gas chromatograph with four ECD-GC channels and two mass selective detector-gas chromatograph (MSD-GC) channels that double the sampling rate to 180 seconds by using two traps and columns. The ECD-GC channels measure N2O, SF6, CFC-11, CFC-12, halon-1211, and PAN once every 70 seconds, H2, CH4, and CO once every 140 seconds. The two MSD-GC channels measure methyl halides (CH3I, CH3Cl, CH3I), HCFCs (22, 141b, 142b), HFC-134a, sulfur gases (COS and CS2) once every 180 seconds. These data represent a diversity of atmospheric lifetimes and are useful in examining transport in UT/LS. One example is the tracer-tracer correlation plot of N2O versus SF6, which shows three distinction regions of transport, LS, tropospause transition, and UT. Tropospheric gradients for both gases are apparent in the UT region. Other correlations will be shown in this presentation. A comparison of common species measured between UCATS and PANTHER shows a better than one percent agreement between the two instruments.

A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias).

PubMed

Wood, Chris M; Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J

2013-01-01

The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L(-1) urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L(-1) with osmotic compensation by 175 mmol L(-1) mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L(-1)) to those of urea (175 mmol L(-1)), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

Impact of Convection and Long Range Transport on Short-Lived Trace Gases in the UT/LS

NASA Astrophysics Data System (ADS)

Atlas, E. L.; Schauffler, S.; Navarro, M. A.; Lueb, R.; Hendershot, R.; Ueyama, R.

2017-12-01

Chemical composition of the air in the upper troposphere/lower stratosphere is controlled by a balance of transport, photochemistry, and physical processes, such as interactions with clouds, ice, and aerosol. The chemistry of the air masses that reach the upper troposphere can potentially have profound impacts on the chemistry in the near tropopause region. For example, the transport of reactive organic halogens and their transformation to inorganic halogen species, e.g., Br, BrO, etc., can have a significant impact on ozone budgets in this region and even deeper the stratosphere. Trace gas measurements in the region near the tropopause can also indicate potential sources of surface emissions that are transported to high altitudes. Measurement of trace gases, including such compounds as non-methane hydrocarbons, hydrochlorofluorocarbons, halogenated solvents, methyl halides, etc., can be used to characterize source emissions from industrial, urban, biomass burning, or marine origins. Recent airborne research campaigns have been conducted to better characterize the chemical composition and variations in the UT/LS region. This presentation will discuss these measurements, with a special emphasis on the role of convection and transport in modifying the chemical composition of the UT/LS.

75 FR 62627 - Environmental Impact Statement; Davis County, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... County, UT AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice of Intent. SUMMARY: FWHA is... cooperation with the Utah Department of Transportation (UDOT), will prepare an EIS on a proposal to address... and need and are based on agency and public input. These alternatives include: (1) Taking no action...

Dietary protein affects urea transport across rat urothelia.

PubMed

Spector, David A; Deng, Jie; Stewart, Kerry J

2012-10-01

Recent evidence suggests that regulated solute transport occurs across mammalian lower urinary tract epithelia (urothelia). To study the effects of dietary protein on net urothelial transport of urea, creatinine, and water, we used an in vivo rat bladder model designed to mimic physiological conditions. We placed groups of rats on 3-wk diets differing only by protein content (40, 18, 6, and 2%) and instilled 0.3 ml of collected urine in the isolated bladder of anesthetized rats. After 1 h dwell, retrieved urine volumes were unchanged, but mean urea nitrogen (UN) and creatinine concentrations fell 17 and 4%, respectively, indicating transurothelial urea and creatinine reabsorption. The fall in UN (but not creatinine) concentration was greatest in high protein (40%) rats, 584 mg/dl, and progressively less in rats receiving lower protein content: 18% diet, 224 mg/dl; 6% diet, 135 mg/dl; and 2% diet, 87 mg/dl. The quantity of urea reabsorbed was directly related to a urine factor, likely the concentration of urea in the instilled urine. In contrast, the percentage of instilled urea reabsorbed was greater in the two dietary groups receiving the lowest protein (26 and 23%) than in those receiving higher protein (11 and 9%), suggesting the possibility that a bladder/urothelial factor, also affected by dietary protein, may have altered bladder permeability. These findings demonstrate significant regulated urea transport across the urothelium, resulting in alteration of urine excreted by the kidneys, and add to the growing evidence that the lower urinary tract may play an unappreciated role in mammalian solute homeostasis.

Hydration status affects urea transport across rat urothelia.

PubMed

Spector, David A; Deng, Jie; Stewart, Kerry J

2011-12-01

Although mammalian urinary tract epithelium (urothelium) is generally considered impermeable to water and solutes, recent data suggest that urine constituents may be reabsorbed during urinary tract transit and storage. To study water and solute transport across the urothelium in an in vivo rat model, we instilled urine (obtained during various rat hydration conditions) into isolated in situ rat bladders and, after a 1-h dwell, retrieved the urine and measured the differences in urine volume and concentration and total quantity of urine urea nitrogen and creatinine between instilled and retrieved urine in rat groups differing by hydration status. Although urine volume did not change >1.9% in any group, concentration (and quantity) of urine urea nitrogen in retrieved urine fell significantly (indicating reabsorption of urea across bladder urothelia), by a mean of 18% (489 mg/dl, from an instilled 2,658 mg/dl) in rats receiving ad libitum water and by a mean of 39% (2,544 mg/dl, from an instilled 6,204 mg/dl) in water-deprived rats, but did not change (an increase of 15 mg/dl, P = not significant, from an instilled 300 mg/dl) in a water-loaded rat group. Two separate factors affected urea nitrogen reabsorption rates, a urinary factor related to hydration status, likely the concentration of urea nitrogen in the instilled urine, and a bladder factor(s), also dependent on the animal's state of hydration. Urine creatinine was also absorbed during the bladder dwell, and hydration group effects on the concentration and quantity of creatinine reabsorbed were qualitatively similar to the hydration group effect on urea transport. These findings support the notion(s) that urinary constituents may undergo transport across urinary tract epithelia, that such transport may be physiologically regulated, and that urine is modified during transit and storage through the urinary tract.

Sources of tropospheric ozone along the Asian Pacific Rim: An analysis of ozonesonde observations

NASA Astrophysics Data System (ADS)

Liu, Hongyu; Jacob, Daniel J.; Chan, Lo Yin; Oltmans, Samuel J.; Bey, Isabelle; Yantosca, Robert M.; Harris, Joyce M.; Duncan, Bryan N.; Martin, Randall V.

2002-11-01

The sources contributing to tropospheric ozone over the Asian Pacific Rim in different seasons are quantified by analysis of Hong Kong and Japanese ozonesonde observations with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations. Particular focus is placed on the extensive observations available from Hong Kong in 1996. In the middle-upper troposphere (MT-UT), maximum Asian pollution influence along the Pacific Rim occurs in summer, reflecting rapid convective transport of surface pollution. In the lower troposphere (LT) the season of maximum Asian pollution influence shifts to summer at midlatitudes from fall at low latitudes due to monsoonal influence. The UT ozone minimum and high variability observed over Hong Kong in winter reflects frequent tropical intrusions alternating with stratospheric intrusions. Asian biomass burning makes a major contribution to ozone at <32°N in spring. Maximum European pollution influence (<5 ppbv) occurs in spring in the LT. North American pollution influence exceeds European influence in the UT-MT, reflecting the uplift from convection and the warm conveyor belts over the eastern seaboard of North America. African outflow makes a major contribution to ozone in the low-latitude MT-UT over the Pacific Rim during November-April. Lightning influence over the Pacific Rim is minimum in summer due to westward UT transport at low latitudes associated with the Tibetan anticyclone. The Asian outflow flux of ozone to the Pacific is maximum in spring and fall and includes a major contribution from Asian anthropogenic sources year-round.

Sources of Tropospheric Ozone along the Asian Pacific Rim: An Analysis of Ozonesonde Observations

NASA Technical Reports Server (NTRS)

Liu, Hong-Yu; Jacob, Daniel J.; Chan, Lo Yin; Oltmans, Samuel J.; Bey, Isabelle; Yantosca, Robert M.; Harris, Joyce M.; Duncan, Bryan N.; Martin, Randall V.

2002-01-01

The sources contributing to tropospheric ozone over the Asian Pacific Rim in different seasons are quantified by analysis of Hong Kong and Japanese ozonesonde observations with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations. Particular focus is placed on the extensive observations available from Hong Kong in 1996. In the middle-upper troposphere (MT- UT), maximum Asian pollution influence along the Pacific Rim occurs in summer, reflecting rapid convective transport of surface pollution. In the lower troposphere (LT) the season of maximum Asian pollution influence shifts to summer at midlatitudes from fall at low latitudes due to monsoonal influence. The UT ozone minimum and high variability observed over Hong Kong in winter reflects frequent tropical intrusions alternating with stratospheric intrusions. Asian biomass burning makes a major contribution to ozone at less than 32 deg.N in spring. Maximum European pollution influence (less than 5 ppbv) occurs in spring in the LT. North American pollution influence exceeds European influence in the UT-MT, reflecting the uplift from convection and the warm conveyor belts over the eastern seaboard of North America. African outflow makes a major contribution to ozone in the low-latitude MT-UT over the Pacific Rim during November- April. Lightning influence over the Pacific Rim is minimum in summer due to westward UT transport at low latitudes associated with the Tibetan anticyclone. The Asian outflow flux of ozone to the Pacific is maximum in spring and fall and includes a major contribution from Asian anthropogenic sources year-round.

A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias)

PubMed Central

Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J.

2013-01-01

The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L−1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L−1 with osmotic compensation by 175 mmol L−1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L−1) to those of urea (175 mmol L−1), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane. PMID:23638369

Effect of dietary nitrogen content and intravenous urea infusion on ruminal and portal-drained visceral extraction of arterial urea in lactating Holstein cows.

PubMed

Kristensen, N B; Storm, A C; Larsen, M

2010-06-01

Urea extraction across ruminal and portal-drained visceral (PDV) tissues were investigated using 9 rumen-cannulated and multi-catheterized lactating dairy cows adapted to low-N (12.9% crude protein) and high-N (17.1% crude protein) diets in a crossover design. The interaction between adaptation to dietary treatments and blood plasma concentrations of urea was studied by dividing samplings into a 2.5-h period without urea infusion followed by a 2.5-h period with primed continuous intravenous infusion of urea (0.493+/-0.012 mmol/kg of BW per h). Cows were sampled at 66+/-14 and 68+/-12 d in milk and produced 42+/-1 and 36+/-1 kg of milk/d with the high-N and low-N diets, respectively. The arterial blood urea concentration before urea infusion was 1.37 and 4.09+/-0.18 mmol/L with low-N and high-N, respectively. Dietary treatment did not affect the urea infusion-induced increase in arterial urea concentration (1.91+/-0.13 mmol/L). Arterial urea extraction across the PDV and rumen increased from 2.7 to 5.4+/-0.5% and from 7.1 to 23.8+/-2.1% when cows were changed from high-N to low-N, respectively. Urea infusion did not decrease urea extractions, implying that urea transport rates were proportional to arterial urea concentrations. Urea extraction increased more across the rumen wall than across the total PDV for low-N compared with high-N, which implies that a larger proportion of total PDV uptake of arterial urea is directed toward the rumen with decreasing N intake. The ruminal vein - arterial (RA) concentration difference for ammonia increased instantly (first sampling 15 min after initiation of infusion) to the primed intravenous infusion when cows were adapted to the low-N diet. The RA difference for ammonia correlated poorly to the ventral ruminal concentration of ammonia (r=0.55). Relating the RA difference for ammonia to a function of both ruminal ammonia concentration and the RA difference for urea markedly improved the fit (r=0.85), indicating that a large fraction of ammonia released to the ruminal vein is absorbed from an epithelial ammonia pool not in equilibrium with the ventral ruminal ammonia pool. Changing cows from high-N to low-N affected the relative blood urea clearance by kidneys and PDV. The clearance by the kidneys decreased from 41 to 27+/-2 L/h and the clearance by the PDV increased from 52 to 105+/-12 L/h when the diet was changed from high-N to low-N. In conclusion, urea transport across gut epithelia in cattle is adapting to N status and driven by mass action. Data are commensurable with a model for urea transport across gut epithelia based on regulated expression or activity of facilitative urea transporters. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Air impacts from three alternatives for producing JP-8 jet fuel.

PubMed

Kositkanawuth, Ketwalee; Gangupomu, Roja Haritha; Sattler, Melanie L; Dennis, Brian H; MacDonnell, Frederick M; Billo, Richard; Priest, John W

2012-10-01

To increase U.S. petroleum energy independence, the University of Texas at Arlington (UT Arlington) has developed a direct coal liquefaction process which uses a hydrogenated solvent and a proprietary catalyst to convert lignite coal to crude oil. This sweet crude can be refined to form JP-8 military jet fuel, as well as other end products like gasoline and diesel. This paper presents an analysis of air pollutants resulting from using UT Arlington's liquefaction process to produce crude and then JP-8, compared with 2 alternative processes: conventional crude extraction and refining (CCER), and the Fischer-Tropsch process. For each of the 3 processes, air pollutant emissions through production of JP-8 fuel were considered, including emissions from upstream extraction/ production, transportation, and conversion/refining. Air pollutants from the direct liquefaction process were measured using a LandTEC GEM2000 Plus, Draeger color detector tubes, OhioLumex RA-915 Light Hg Analyzer, and SRI 8610 gas chromatograph with thermal conductivity detector. According to the screening analysis presented here, producing jet fuel from UT Arlington crude results in lower levels of pollutants compared to international conventional crude extraction/refining. Compared to US domestic CCER, the UTA process emits lower levels of CO2-e, NO(x), and Hg, and higher levels of CO and SO2. Emissions from the UT Arlington process for producing JP-8 are estimated to be lower than for the Fischer-Tropsch process for all pollutants, with the exception of CO2-e, which were high for the UT Arlington process due to nitrous oxide emissions from crude refining. When comparing emissions from conventional lignite combustion to produce electricity, versus UT Arlington coal liquefaction to make JP-8 and subsequent JP-8 transport, emissions from the UT Arlington process are estimated to be lower for all air pollutants, per MJ of power delivered to the end user. The United States currently imports two-thirds of its crude oil, leaving its transportation system especially vulnerable to disruptions in international crude supplies. At current use rates, U.S. coal reserves (262 billion short tons, including 23 billion short tons lignite) would last 236 years. Accordingly, the University of Texas at Arlington (UT Arlington) has developed a process that converts lignite to crude oil, at about half the cost of regular crude. According to the screening analysis presented here, producing jet fuel from UT Arlington crude generates lower levels of pollutants compared to international conventional crude extraction/refining (CCER).

Urea transport through composite polyallylamine membranes

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Kubo, L. Y.; Spitze, L. A.; Wydeven, T.; Clark, J. A.

1977-01-01

Polyallylamine composite reverse osmosis membranes were prepared by plasma polymerization and deposition onto small-pored cellulose acetate/cellulose nitrate films. The polyallylamine coated the porous substrate with a thin uniform polymer film which exhibited water permeability and urea rejection, of interest because of the potential application of reverse osmosis to urine purification in closed environmental systems. The flux of C-14 labeled urea was studied under the influence of osmotic gradients provided by sodium chloride solutions. The urea flux was found to be enhanced by an osmotic pressure gradient in the same direction and diminished, but not prevented, by an opposing osmotic pressure gradient. Consideration is given to the mechanism of the urea transport, as well as to the influence of concentration polarization on the experimental results. The minimization of coupled flow in pores of a critical size range is apparently necessary to improve urea rejection.

A protocol for conducting rainfall simulation to study soil runoff.

PubMed

Kibet, Leonard C; Saporito, Louis S; Allen, Arthur L; May, Eric B; Kleinman, Peter J A; Hashem, Fawzy M; Bryant, Ray B

2014-04-03

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24 hr after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff.

A Protocol for Conducting Rainfall Simulation to Study Soil Runoff

PubMed Central

Kibet, Leonard C.; Saporito, Louis S.; Allen, Arthur L.; May, Eric B.; Kleinman, Peter J. A.; Hashem, Fawzy M.; Bryant, Ray B.

2014-01-01

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24 hr after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff. PMID:24748061

The Governing Processes and Timescales of Stratosphere-to-Troposphere Transport and its Contribution to Ozone in the Arctic Troposphere

NASA Technical Reports Server (NTRS)

Liang, Q.; Douglass, A. R.; Duncan, B. N.; Stolarski, R. S.; Witte, J. C.

2009-01-01

We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40 deg N to 80 deg N with stratospheric influx in the mid-latitudes (30-70 deg N) accounting for 67.81 percent of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O3 in the Arctic troposphere directly from the transport of O3 and indirectly from the transport of NOy . Direct transport of O3 from the stratosphere accounts for 78 percent of O3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribution decreases significantly in the MT/LT (20.25 percent of total O3) and shows a very weak March.April maximum. Our NOx budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NO y-rich air increases NOx concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

Colloid-associated plutonium aged at room temperature: evaluating its transport velocity in saturated coarse-grained granites

NASA Astrophysics Data System (ADS)

Xie, Jinchuan; Lin, Jianfeng; Wang, Yu; Li, Mei; Zhang, Jihong; Zhou, Xiaohua; He, Yifeng

2015-01-01

The fate and transport of colloidal contaminants in natural media are complicated by physicochemical properties of the contaminants and heterogeneous characteristics of the media. Size and charge exclusion are two key microscopic mechanisms dominating macroscopic transport velocities. Faster velocities of colloid-associated actinides than that of 3H2O were consistently indicated in many studies. However, dissociation/dissolution of these sorbed actinides (e.g., Pu and Np), caused by their redox reactions on mineral surfaces, possibly occurred under certain chemical conditions. How this dissolution is related to transport velocities remains unanswered. In this study, aging of the colloid-associated Pu (pseudo-colloid) at room temperature and transport through the saturated coarse-grained granites were performed to study whether Pu could exhibit slower velocity than that of 3H2O (UPu/UT < 1). The results show that oxidative dissolution of Pu(IV) associated with the surfaces of colloidal granite particles took place during the aging period. The relative velocity of UPu/UT declined from 1.06 (unaged) to 0.745 (135 d) over time. Size exclusion limited to the uncharged nano-sized particles could not explain such observed UPu/UT < 1. Therefore, the decline in UPu/UT was ascribed to the presence of electrostatic attraction between the negatively charged wall of granite pore channels and the Pu(V)O2+, as evidenced by increasing Pu(V)O2+ concentrations in the suspensions aged in sealed vessels. As a result of this attraction, Pu(V)O2+ was excluded from the domain closer to the centerline of pore channels. This reveals that charge exclusion played a more important role in dominating UPu than the size exclusion under the specific conditions, where oxidative dissolution of colloid-associated Pu(IV) was observed in the aged suspensions.

The TonB-dependent Transporter FhuA in Planar Lipid Bilayers: partial exit of its plug from the barrel

PubMed Central

Udho, Eshwar; Jakes, Karen S.; Finkelstein, Alan

2012-01-01

TonB-dependent transporters (TBDTs), which transport iron-chelating siderophores and vitamin B12 across the outer membrane of gram negative bacteria, share a conserved architecture of a 22-stranded beta-barrel with an amino-terminal plug domain occluding the barrel. We previously reported that we could induce TBDTs to reversibly open in planar lipid bilayers via the use of urea and that these channels were responsive to physiological concentrations of ligands. Here we report that in the presence of urea, trypsin can cleave the amino-terminal 67 residues of the plug of the TonB-dependent transporter FhuA, as assessed by gel shift and mass spectrometry assays. On the bilayer, trypsin treatment in the presence of urea resulted in the induced conductance no longer being reversed upon removal of urea, suggesting that urea opens intact FhuA channels by pulling the plug at least partly out of the barrel, and that removal of the urea then allows reinsertion of the plug into the barrel. When expressed separately, the FhuA plug domain was found to be a mostly unfolded structure that was able to occlude isolated FhuA beta-barrels inserted into the membrane. Thus, although folded in the barrel, the plug need not be folded upon exiting the barrel. The rate of insertion of the beta-barrels into the membrane was tremendously increased in the presence of an osmotic gradient provided by either urea or glycerol. Negative staining electron microscopy showed that FhuA in a detergent solution formed vesicles, thus explaining why an osmotic gradient promoted the insertion of FhuA into membranes. PMID:22846061

Understanding Strategy of Nitrate and Urea Assimilation in a Chinese Strain of Aureococcus anophagefferens through RNA-Seq Analysis

PubMed Central

Dong, Hong-Po; Huang, Kai-Xuan; Wang, Hua-Long; Lu, Song-Hui; Cen, Jing-Yi; Dong, Yue-Lei

2014-01-01

Aureococcus anophagefferens is a harmful alga that dominates plankton communities during brown tides in North America, Africa, and Asia. Here, RNA-seq technology was used to profile the transcriptome of a Chinese strain of A. anophagefferens that was grown on urea, nitrate, and a mixture of urea and nitrate, and that was under N-replete, limited and recovery conditions to understand the molecular mechanisms that underlie nitrate and urea utilization. The number of differentially expressed genes between urea-grown and mixture N-grown cells were much less than those between urea-grown and nitrate-grown cells. Compared with nitrate-grown cells, mixture N-grown cells contained much lower levels of transcripts encoding proteins that are involved in nitrate transport and assimilation. Together with profiles of nutrient changes in media, these results suggest that A. anophagefferens primarily feeds on urea instead of nitrate when urea and nitrate co-exist. Furthermore, we noted that transcripts upregulated by nitrate and N-limitation included those encoding proteins involved in amino acid and nucleotide transport, degradation of amides and cyanates, and nitrate assimilation pathway. The data suggest that A. anophagefferens possesses an ability to utilize a variety of dissolved organic nitrogen. Moreover, transcripts for synthesis of proteins, glutamate-derived amino acids, spermines and sterols were upregulated by urea. Transcripts encoding key enzymes that are involved in the ornithine-urea and TCA cycles were differentially regulated by urea and nitrogen concentration, which suggests that the OUC may be linked to the TCA cycle and involved in reallocation of intracellular carbon and nitrogen. These genes regulated by urea may be crucial for the rapid proliferation of A. anophagefferens when urea is provided as the N source. PMID:25338000

Transportation cost index : a comprehensive performance measure for transportation and land and its application in OR, FL, and UT : final report.

DOT National Transportation Integrated Search

2017-04-01

MAP-21 and state laws are placing increasing emphasis on using comprehensive transportation performance measures that include mobility, : safety, economy, livability, equity, and environmental to guide transportation decision-making. One of the tough...

76 FR 40354 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

.... 20110216, Final EIS, FHWA, UT, Hyde Park/North Logan Corridor Project, Proposed 200 East Transportation Corridor between North Logan City and Hyde Park, Funding, Right-of-Way Acquisitions and US Army COE Section 404 Permit, Cache County, UT, Review Period Ends: 08/08/2011, Contact: Paul C. Ziman 801-955-3525...

Examining urea flux across the intestine of the spiny dogfish, Squalus acanthias.

PubMed

Gary Anderson, W; McCabe, Chris; Brandt, Catherine; Wood, Chris M

2015-03-01

Recent examination of urea flux in the intestine of the spiny dogfish shark, Squalus acanthias, has shown that feeding significantly enhances urea uptake across the intestine, and this was significantly inhibited following mucosal addition of phloretin. The present study examined potential mechanisms of urea uptake across the dogfish intestine in starved and fed dogfish. Unidirectional flux chambers were used to examine the kinetics of urea uptake, and to determine the influence of sodium, ouabain, competitive urea analogues, and phloretin on urea uptake across the gut of fed dogfish. Intestinal epithelial preparations from starved and fed dogfish were mounted in Ussing chambers to examine the effect of phloretin on bidirectional solute transport across the intestine. In the unidirectional studies, the maximum uptake rate of urea was found to be 35.3±6.9 μmol.cm(-2).h(-1) and Km was found to be 291.8±9.6 mM in fed fish, and there was a mild inhibition of urea uptake following mucosal addition of competitive agonists. Addition of phloretin, Na-free Ringers and ouabain to the mucosal side of intestinal epithelia also led to a significant reduction in urea uptake in fed fish. In the Ussing chamber studies there was a net influx of urea in fed fish and a small insignificant efflux in starved fish. Addition of phloretin blocked urea uptake in fed fish when added to the mucosal side. Furthermore, phloretin had no effect on ion transport across the intestinal epithelia with the exception of the divalent cations, magnesium and calcium. Copyright © 2015 Elsevier Inc. All rights reserved.

Exploring The Relation Between Upper Tropospheric (UT) Clouds and Convection

NASA Astrophysics Data System (ADS)

Stephens, G. L.; Stubenrauch, C.

2017-12-01

The importance of knowing the vertical transports of water vapor and condensate by atmospheric moist convection cannot be overstated. Vertical convective transports have wide-ranging influences on the Earth system, shaping weather, climate, the hydrological cycle and the composition of the atmosphere. These transports also influence the upper tropospheric cloudiness that exerts profound effects on climate. Although there are presently no direct observations to quantify these transports on the large scale, and there are no observations to constrain model assumptions about them, it might be possible to derive useful observations proxies of these transports and their influence. This talk will present results derived from a large community effort that has developed important observations data records that link clouds and convection. Steps to use these observational metrics to examine the relation between convection, UT clouds in both cloud and global scale models are exemplified and important feedbacks between high clouds, radiation and convection will be elucidated.

Mutant Potential Ubiquitination Sites in Dur3p Enhance the Urea and Ethyl Carbamate Reduction in a Model Rice Wine System.

PubMed

Zhang, Peng; Du, Guocheng; Zou, Huijun; Xie, Guangfa; Chen, Jian; Shi, Zhongping; Zhou, Jingwen

2017-03-01

Ubiquitination can significantly affect the endocytosis and degradation of plasma membrane proteins. Here, the ubiquitination of a Saccharomyces cerevisiae urea plasma membrane transporter (Dur3p) was altered. Two potential ubiquitination sites, lysine residues K556 and K571, of Dur3p were predicted and replaced by arginine, and the effects of these mutations on urea utilization and formation under different nitrogen conditions were investigated. Compared with Dur3p, the Dur3p K556R mutant showed a 20.1% decrease in ubiquitination level in yeast nitrogen base medium containing urea and glutamine. It also exhibited a >75.8% decrease in urea formation in yeast extract-peptone-dextrose medium and 41.3 and 55.4% decreases in urea and ethyl carbamate formation (a known carcinogen), respectively, in a model rice wine system. The results presented here show that the mutation of Dur3p ubiquitination sites could significantly affect urea utilization and formation. Modifying the ubiquitination of specific transporters might have promising applications in rationally engineering S. cerevisiae strains to efficiently use specific nitrogen sources.

Effects of dietary fibre and protein on urea transport across the cecal mucosa of piglets.

PubMed

Stumpff, F; Lodemann, U; Van Kessel, A G; Pieper, R; Klingspor, S; Wolf, K; Martens, H; Zentek, J; Aschenbach, J R

2013-12-01

In ruminants, gastrointestinal recycling of urea is acutely enhanced by fibre-rich diets that lead to high ruminal concentration of short chain fatty acids (SCFA), while high ammonia has inhibitory effects. This study attempted to clarify if urea flux to the porcine cecum is similarly regulated. Thirty-two weaned piglets were fed diets containing protein (P) of poor prececal digestibility and fibre (F) at high (H) or low levels (L) in a 2 × 2 factorial design. After slaughter, cecal content was analyzed and the cecal mucosa incubated in Ussing chambers to measure the effect of pH, SCFA and NH4 (+) on the flux rates of urea, short-circuit current (I sc) and tissue conductance (G t). NH4 (+) significantly enhanced I sc (from 0.5 ± 0.2 to 1.2 ± 0.1 μEq cm(-2) h(-1)). No acute effects of SCFA or ammonia on urea flux were observed. Tissue conductance was significantly lower in the high dietary fibre groups irrespective of the protein content. Only the HP-LF group emerged as different from all others in terms of urea flux (74 ± 6 versus 53 ± 3 nmol cm(-2) h(-1)), associated with higher cecal ammonia concentration and reduced fecal consistency. The data suggest that as in the rumen, uptake of ammonia by the cecum may involve electrogenic transport of the ionic form (NH4 (+)). In contrast to findings in the rumen, neither a high fibre diet nor acute addition of SCFA enhanced urea transport across the pig cecum. Instead, a HP-LF diet had stimulatory effects. A potential role for urea recycling in stabilizing luminal pH is discussed.

Using Long-Term Observations of VOCs from the CARIBIC Observatory to Refine Understanding of Transport and Chemistry in the UT/LS

NASA Astrophysics Data System (ADS)

Baker, A. K.; Thorenz, U. R.; Sauvage, C.; Riede, H.; Umezawa, T.; Williams, J.; Zahn, A.; Brenninkmeijer, C. A. M.

2014-12-01

Volatile organic compounds (VOCs) are ubiquitous trace components of the atmosphere, arising from a variety of natural and anthropogenic sources. Their wide range of lifetimes and specific source signatures make VOCs useful indicators of source region, photochemical histories and transport timescales of air masses. This is particularly true of the C2-C5non-methane hydrocarbons (NMHCs), which are predominantly anthropogenic in origin, have relatively well-known emission ratios, and lifetimes ranging from days to months. NMHCs are also frequently measured in an ensemble analysis, as is the case for whole air samples collected during deployments of the CARIBIC observatory (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container; www.caribic-atmospheric.com). Since 2005 the CARIBIC observatory operates from onboard a Lufthansa Airlines A340-600, where it is deployed monthly to make detailed observations of the atmosphere during a series of 2-6 long-distance commercial flights. The container operates at aircraft cruise altitudes of 10-12 km, placing the observations primarily in the upper troposphere and lowermost stratosphere (UT/LS). There is a dearth of information about distributions of VOCs in the UT/LS, and data is generally restricted to measurements during short-term field campaigns. However, when data are available, VOC studies have proven to be well-suited to investigations in the UT/LS, where air masses are remote from sources and background air is relatively homogeneous. Here we take advantage of the over 5000 measurements of VOCs from air samples collected during nearly 10 years of CARIBIC flights in order to better understand transport and chemistry in the tropopause region. First, we use NMHC observations to identify "hot spots" for rapid transport of boundary layer air to the UT via convection or warm conveyor belts by examining the relationships of shorter-lived species to longer-lived ones and comparison to background air. Similarly, observations in the LS are used to identify instances of rapid transport across the mid-latitude tropopause and to estimate timescales of these processes. Finally, we complement our NMHC analysis with observations of CH3Cl and demonstrate its utility as a tracer for tropical air in the mid-latitude LS.

Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

NASA Technical Reports Server (NTRS)

Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

2005-01-01

The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

Morphological and functional characteristics of the kidney of cartilaginous fishes: with special reference to urea reabsorption.

PubMed

Hyodo, Susumu; Kakumura, Keigo; Takagi, Wataru; Hasegawa, Kumi; Yamaguchi, Yoko

2014-12-15

For adaptation to high-salinity marine environments, cartilaginous fishes (sharks, skates, rays, and chimaeras) adopt a unique urea-based osmoregulation strategy. Their kidneys reabsorb nearly all filtered urea from the primary urine, and this is an essential component of urea retention in their body fluid. Anatomical investigations have revealed the extraordinarily elaborate nephron system in the kidney of cartilaginous fishes, e.g., the four-loop configuration of each nephron, the occurrence of distinct sinus and bundle zones, and the sac-like peritubular sheath in the bundle zone, in which the nephron segments are arranged in a countercurrent fashion. These anatomical and morphological characteristics have been considered to be important for urea reabsorption; however, a mechanism for urea reabsorption is still largely unknown. This review focuses on recent progress in the identification and mapping of various pumps, channels, and transporters on the nephron segments in the kidney of cartilaginous fishes. The molecules include urea transporters, Na(+)/K(+)-ATPase, Na(+)-K(+)-Cl(-) cotransporters, and aquaporins, which most probably all contribute to the urea reabsorption process. Although research is still in progress, a possible model for urea reabsorption in the kidney of cartilaginous fishes is discussed based on the anatomical features of nephron segments and vascular systems and on the results of molecular mapping. The molecular anatomical approach thus provides a powerful tool for understanding the physiological processes that take place in the highly elaborate kidney of cartilaginous fishes. Copyright © 2014 the American Physiological Society.

First In-situ Measurements of the HDO/H2O Isotopic Ratio in the Asian Summer Monsoon

NASA Astrophysics Data System (ADS)

Clouser, B.; Sarkozy, L.; Gaeta, D. C.; Singer, C. E.; Moyer, E. J.

2017-12-01

The Asian monsoon is one of the world's largest weather systems, and forms one of the main pathways by which water vapor enters the UT/LS. Satellite measurements of the HDO/H2O ratio of UT/LS water, a strong tracer of convective origin, have suggested significant differences in transport behavior between the Asian and North American monsoons, with strong UT/LS enhancement occurring only over North America. We report here the first in-situ measurements of the HDO/H2O ratio in the Asian monsoon, that help resolve this discrepancy. The Chicago Water Isotope Spectrometer (Chi-WIS) participated in the July/August 2017 StratoClim campaign, measuring water vapor and its isotopic composition between 12 and 20 kilometers. We use these measurements to diagnose the importance of overshooting convection in water transport by the Asian monsoon, and to characterize the extent to which convection-driven water vapor perturbations propagate to higher altitudes and contribute to the overall stratospheric water budget.

Measuring urea persistence, distribution and transport on coastal plain soils

USDA-ARS?s Scientific Manuscript database

The persistence and mobility of urea, an organic form of nitrogen present in animal manures and commercial fertilizers, has rarely been studied and measured, because it is assumed to undergo rapid hydrolysis to ammonia. However, preliminary studies have shown urea to exist in leachate and runoff sev...

Investigating Convection and Cross-Tropopause Transport Using Long-Term Observations of NMHCs in the UT/LS from the IAGOS-CARIBIC Observatory

NASA Astrophysics Data System (ADS)

Baker, A. K.; Thorenz, U. R.; Sauvage, C.; Brenninkmeijer, C. A. M.; Williams, J.

2015-12-01

Since 2005 the IAGOS-CARIBIC observatory (In-service Aircraft for a Global Observing System - Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container; www.caribic-atmospheric.com) has made detailed observations of atmospheric composition from onboard a Lufthansa Airlines A340-600 passenger aircraft. The observatory is deployed once per month for a series of 2-6 long-distance flights and operates at aircraft cruise altitude (10-12 km), placing the observations predominantly in the upper troposphere and lowermost stratosphere (UT/LS). The IAGOS-CARIBIC payload includes instruments to make in situ trace gas and aerosol observations, as well as a system for the collection of whole air samples for post flight analysis of greenhouse gases, halocarbons, and non-methane hydrocarbons (NMHCs). NMHCs are particularly useful indicators of air mass sources and transport histories, and using the relationships between different hydrocarbons in the UT/LS we have identified regions of the upper troposphere regularly influenced by strong convection as well as instances of rapid cross-tropopause transport. Here we provide an overview of our findings along with a more detailed description of our observations in far northern latitudes, where we frequently observed air with high tropospheric character in the lower stratosphere during spring.

Dialyzer clearances and mass transfer-area coefficients for small solutes at low dialysate flow rates.

PubMed

Leypoldt, John K; Kamerath, Craig D; Gilson, Janice F; Friederichs, Goetz

2006-01-01

New daily hemodialysis therapies operate at low dialysate flow rates to minimize dialysate volume requirements; however, the dependence of dialyzer clearances and mass transfer-area coefficients for small solutes on dialysate flow rate under these conditions have not been studied extensively. We evaluated in vitro dialyzer clearances for urea and creatinine at dialysate flow rates of 40, 80, 120, 160, and 200 ml/min and ultrafiltration flow rates of 0, 1, and 2 l/h, using a dialyzer containing PUREMA membranes (NxStage Medical, Lawrence, MA). Clearances were measured directly across the dialyzer by perfusing bovine blood with added urea and creatinine single pass through the dialyzer at a nominal blood flow rate of 400 ml/min. Limited, additional studies were performed with the use of dialyzers containing PUREMA membranes at a blood flow rate of 200 ml/min and also with the use of other dialyzers containing polysulfone membranes (Optiflux 160NR, FMC-NA, Ogden, UT) and dialyzers containing Synphan membranes (NxStage Medical). For dialyzers containing PUREMA membranes, urea and creatinine clearances increased (p < 0.001) with increasing dialysate and ultrafiltration flow rates but were not different at blood flow rates of 200 and 400 ml/min. Dialysate saturation, defined as dialysate outlet concentration divided by blood water inlet concentration, for urea and creatinine was independent of blood and ultrafiltration flow rate but varied inversely (p < 0.001) with dialysate flow rate. Mass transfer-area coefficients for urea and creatinine were independent of blood and ultrafiltration flow rate but decreased (p < 0.001) with decreasing dialysate flow rate. Calculated mass transfer-area coefficients at low dialysate flow rates for all dialyzers tested were substantially lower than those reported by the manufacturers under conventional conditions. We conclude that dialyzers require specific characterization under relevant conditions if they are used in novel daily hemodialysis therapies at low dialysate flow rate.

Backfilling behavior of a mixed aggregate based on construction waste and ultrafine tailings

PubMed Central

Zhang, Qinli; Xiao, Chongchun; Chen, Xin

2017-01-01

To study the possibility of utilizing mixed construction waste and ultrafine tailings (CW&UT) as a backfilling aggregate that can be placed underground in a mine, physicochemical evaluation, proportioning strength tests, and pumpability experiments were conducted. It was revealed that mixed CW&UT can be used as a backfilling aggregate due to the complementarities of their physicochemical properties. In addition, as the results of the proportioning strength tests show, the compressive strength of a cemented CW&UT backfilling specimen cured for 28 days, with a mass fraction of 72–74%, a cement-sand ratio of 1:12, and a CW proportion of 30%, is higher than 1.0 MPa, which meets the safety requirements and economic consideration of backfilling technology in many underground metal mines, and can also be enhanced with an increase in the cement-sand ratio. The results of the pumpability experiments show that cemented backfilling slurry based on CW&UT can be transported to the stope underground with a common filling pump, with a 16.6 MPa maximum pressure, with the condition that the time of emergency shut-down is less than approximately 20 min. All in all, the research to utilize mixed CW&UT as a backfilling aggregate can not only provide a way to dispose of CW&UT but also will bring large economic benefits and can provide constructive guidance for environmental protection. PMID:28662072

Backfilling behavior of a mixed aggregate based on construction waste and ultrafine tailings.

PubMed

Chen, Qiusong; Zhang, Qinli; Xiao, Chongchun; Chen, Xin

2017-01-01

To study the possibility of utilizing mixed construction waste and ultrafine tailings (CW&UT) as a backfilling aggregate that can be placed underground in a mine, physicochemical evaluation, proportioning strength tests, and pumpability experiments were conducted. It was revealed that mixed CW&UT can be used as a backfilling aggregate due to the complementarities of their physicochemical properties. In addition, as the results of the proportioning strength tests show, the compressive strength of a cemented CW&UT backfilling specimen cured for 28 days, with a mass fraction of 72-74%, a cement-sand ratio of 1:12, and a CW proportion of 30%, is higher than 1.0 MPa, which meets the safety requirements and economic consideration of backfilling technology in many underground metal mines, and can also be enhanced with an increase in the cement-sand ratio. The results of the pumpability experiments show that cemented backfilling slurry based on CW&UT can be transported to the stope underground with a common filling pump, with a 16.6 MPa maximum pressure, with the condition that the time of emergency shut-down is less than approximately 20 min. All in all, the research to utilize mixed CW&UT as a backfilling aggregate can not only provide a way to dispose of CW&UT but also will bring large economic benefits and can provide constructive guidance for environmental protection.

An in vitro study of urea, water, ion and CO2/HCO3- transport in the gastrointestinal tract of the dogfish shark (Squalus acanthias): the influence of feeding.

PubMed

Liew, Hon Jung; De Boeck, Gudrun; Wood, Chris M

2013-06-01

In vitro gut sac preparations made from the cardiac stomach (stomach 1), pyloric stomach (stomach 2), intestine (spiral valve) and colon were used to examine the impact of feeding on transport processes in the gastrointestinal tract of the dogfish shark. Preparations were made from animals that were euthanized after 1-2 weeks of fasting, or at 24-48 h after voluntary feeding on a 3% ration of teleost fish (hake). Sacs were incubated under initially symmetrical conditions with dogfish saline on both surfaces. In comparison to an earlier in vivo study, the results confirmed that feeding caused increases in H(+) secretion in both stomach sections, but an increase in Cl(-) secretion only in stomach 2. Na(+) absorption, rather than Na(+) secretion, occurred in both stomach sections after feeding. All sections of the tract absorbed water and the intestine strongly absorbed Na(+) and Cl(-), regardless of feeding condition. The results also confirmed that feeding increased water absorption in the intestine (but not in the colon), and had little influence on the handling of Ca(2+) and Mg(2+), which exhibited negligible absorption across the tract. However, K(+) was secreted in the intestine in both fasted and fed preparations. Increased intestinal water absorption occurred despite net osmolyte secretion into the mucosal saline. The largest changes occurred in urea and CO2/HCO3(-) fluxes. In fasted preparations, urea was absorbed at a low rate in all sections except the intestine, where it was secreted. Instead of an increase in intestinal urea secretion predicted from in vivo data, feeding caused a marked switch to net urea absorption. This intestinal urea transport occurred at a rate comparable to urea reabsorption rates reported at gills and kidney, and was apparently active, establishing a large serosal-to-mucosal concentration gradient. Feeding also greatly increased intestinal CO2/HCO3(-) secretion; if interpreted as HCO3(-) transport, the rates were in the upper range of those reported in marine teleosts. Phloretin (0.25 mmol l(-1), applied mucosally) completely blocked the increases in intestinal urea absorption and CO2/HCO3(-) secretion caused by feeding, but had no effect on Na(+), Cl(-) or water absorption.

The Satellite View of Extra-Tropical Stratosphere-Troposphere Exchange and the UT/LS

NASA Technical Reports Server (NTRS)

Schoeberl, Mark R.

2004-01-01

This talk will review satellite studies which have helped define the UT/LS and stratosphere-troposphere exchange. Satellites have provided a global perspective but have had limited temporal and spatial measurements for stratosphere-troposphere exchange (STE) studies. Nonetheless, long lived tracer measurements from satellites can be used as proxies for age-of-air can thus provide estimates of mixing and transport processes in the UT/LS. These measurements can be compared to model estimates of the mean age-of-air and trace gas fluxes providing an important model diagnostic. With the launch of EOS Aura, the potential for satellite trace gas measurements of the lower-most stratosphere and STE is significantly improved, and Aura s mission will be briefly described.

The Role of Convection in Redistributing Formaldehyde to the Upper Troposphere Over North America and the North Atlantic during the Summer 2004 INTEX Campaign

NASA Technical Reports Server (NTRS)

Fried, Alan; Olson, Jennifer R.; Walega, Jim; Crawford, Jim H.; Chen, Gao; Weibring, Petter; Richter, Dirk; Roller, Chad; Tittel, Frank; Porter, Michael;

Folding Properties of Cytosine Monophosphate Kinase from E. coli Indicate Stabilization through an Additional Insert in the NMP Binding Domain

PubMed Central

Beitlich, Thorsten; Lorenz, Thorsten; Reinstein, Jochen

2013-01-01

The globular 25 kDa protein cytosine monophosphate kinase (CMPK, EC ID: 2.7.4.14) from E. coli belongs to the family of nucleoside monophosphate (NMP) kinases (NMPK). Many proteins of this family share medium to high sequence and high structure similarity including the frequently found α/β topology. A unique feature of CMPK in the family of NMPKs is the positioning of a single cis-proline residue in the CORE-domain (cis-Pro124) in conjunction with a large insert in the NMP binding domain. This insert is not found in other well studied NMPKs such as AMPK or UMP/CMPK. We have analyzed the folding pathway of CMPK using time resolved tryptophan and FRET fluorescence as well as CD. Our results indicate that unfolding at high urea concentrations is governed by a single process, whereas refolding in low urea concentrations follows at least a three step process which we interpret as follows: Pro124 in the CORE-domain is in cis in the native state (Nc) and equilibrates with its trans-isomer in the unfolded state (Uc - Ut). Under refolding conditions, at least the Ut species and possibly also the Uc species undergo a fast initial collapse to form intermediates with significant amount of secondary structure, from which the trans-Pro124 fraction folds to the native state with a 100-fold lower rate constant than the cis-Pro124 species. CMPK thus differs from homologous NMP kinases like UMP/CMP kinase or AMP kinase, where folding intermediates show much lower content of secondary structure. Importantly also unfolding is up to 100-fold faster compared to CMPK. We therefore propose that the stabilizing effect of the long NMP-domain insert in conjunction with a subtle twist in the positioning of a single cis-Pro residue allows for substantial stabilization compared to other NMP kinases with α/β topology. PMID:24205218

Growth of urea crystals by physical vapor transport

NASA Technical Reports Server (NTRS)

Feigelson, R. S.; Route, R. K.; Kao, T.-M.

1985-01-01

This work demonstrates that high optical quality crystals of urea can be grown by the physical vapor transport method. The unique features of this method are compared with growth from methanol/water solutions. High growth rates, exceeding 2.5 mm/day, were achieved, and cm-size optical quality single crystals were obtained. Details of the growth technique and the physical properties of the crystals are presented.

Cold recycle pavement using urea urethane dispersion agent and rubber : final report.

DOT National Transportation Integrated Search

1994-12-01

This research study was a joint venture of the Oregon Department of Transportation (ODOT), Evans, Loosely, Inc., and Roseburg Paving Company, to evaluate the use of Urea Urethane Dispersion (UUD) agent, with finely ground tire rubber, high float emul...

Urea metabolism in plants.

PubMed

Witte, Claus-Peter

2011-03-01

Urea is a plant metabolite derived either from root uptake or from catabolism of arginine by arginase. In agriculture, urea is intensively used as a nitrogen fertilizer. Urea nitrogen enters the plant either directly, or in the form of ammonium or nitrate after urea degradation by soil microbes. In recent years various molecular players of plant urea metabolism have been investigated: active and passive urea transporters, the nickel metalloenzyme urease catalyzing the hydrolysis of urea, and three urease accessory proteins involved in the complex activation of urease. The degradation of ureides derived from purine breakdown has long been discussed as a possible additional metabolic source for urea, but an enzymatic route for the complete hydrolysis of ureides without a urea intermediate has recently been described for Arabidopsis thaliana. This review focuses on the proteins involved in plant urea metabolism and the metabolic sources of urea but also addresses open questions regarding plant urea metabolism in a physiological and agricultural context. The contribution of plant urea uptake and metabolism to fertilizer urea usage in crop production is still not investigated although globally more than half of all nitrogen fertilizer is applied to crops in the form of urea. Nitrogen use efficiency in crop production is generally well below 50% resulting in economical losses and creating ecological problems like groundwater pollution and emission of nitric oxides that can damage the ozone layer and function as greenhouse gasses. Biotechnological approaches to improve fertilizer urea usage bear the potential to increase crop nitrogen use efficiency. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Short-Term Treatment with the Urease Inhibitor N-(n-Butyl) Thiophosphoric Triamide (NBPT) Alters Urea Assimilation and Modulates Transcriptional Profiles of Genes Involved in Primary and Secondary Metabolism in Maize Seedlings

PubMed Central

Zanin, Laura; Venuti, Silvia; Tomasi, Nicola; Zamboni, Anita; De Brito Francisco, Rita M.; Varanini, Zeno; Pinton, Roberto

2016-01-01

To limit nitrogen (N) losses from the soil, it has been suggested to provide urea to crops in conjunction with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT). However, recent studies reported that NBPT affects urea uptake and urease activity in plants. To shed light on these latter aspects, the effects of NBPT were studied analysing transcriptomic and metabolic changes occurring in urea-fed maize seedlings after a short-term exposure to the inhibitor. We provide evidence that NBPT treatment led to a wide reprogramming of plant metabolism. NBPT inhibited the activity of endogenous urease limiting the release and assimilation of ureic-ammonium, with a simultaneous accumulation of urea in plant tissues. Furthermore, NBPT determined changes in the glutamine, glutamate, and asparagine contents. Microarray data indicate that NBPT affects ureic-N assimilation and primary metabolism, such as glycolysis, TCA cycle, and electron transport chain, while activates the phenylalanine/tyrosine-derivative pathway. Moreover, the expression of genes relating to the transport and complexation of divalent metals was strongly modulated by NBPT. Data here presented suggest that when NBPT is provided in conjunction with urea an imbalance between C and N compounds might occur in plant cells. Under this condition, root cells also seem to activate a response to maintain the homeostasis of some micronutrients. PMID:27446099

Distribution of extracellular matrix molecules in human uterine tubes during the menstrual cycle: a histological and immunohistochemical analysis.

PubMed

Godoy-Guzmán, Carlos; Nuñez, Claudio; Orihuela, Pedro; Campos, Antonio; Carriel, Víctor

2018-04-16

The uterine tube (UT) is an important and complex organ of the women's reproductive system. In general, the anatomy and basic histology of this organ are well-known. However, the composition and function of the extracellular matrix (ECM) of the UT is still poorly understood. The ECM is a complex supramolecular material produced by cells which is commonly restricted to the basement membrane and interstitial spaces. ECM molecules play not only a structural role, they are also important for cell growth, survival and differentiation in all tissues. In this context, the aim of this study was to evaluate the deposition and distribution of type I and III collagens and proteoglycans (decorin, biglycan, fibromodulin and versican) in human UT during the follicular and luteal phases by using histochemical and immunohistochemical techniques. Our results showed a broad synthesis of collagens (I and III) in the stroma of the UT. The analysis by regions showed, in the mucosa, a specific distribution of versican and fibromodulin in the epithelial surface, whereas decorin and fibromodulin were observed in the lamina propria. Versican and decorin were found in the stroma of the muscular layer, whereas all studied proteoglycans were identified in the serosa. Curiously, biglycan was restricted to the wall of the blood vessels of the serosa and muscular layers. Furthermore, there was an immunoreaction for collagens, decorin, versican and fibromodulin in the UT peripheral nerves. The differential distribution of these ECM molecules in the different layers of the UT could be related to specific structural and/or biomechanical functions needed for the oviductal transport, successful fertilization and early embryogenesis. However, further molecular studies under physiological and pathological conditions are still needed to elucidate the specific role of each molecule in the human UT. © 2018 Anatomical Society.

Light exposure enhances urea absorption in the fluted giant clam, Tridacna squamosa, and up-regulates the protein abundance of a light-dependent urea active transporter, DUR3-like, in its ctenidium.

PubMed

Chan, Christabel Y L; Hiong, Kum C; Boo, Mel V; Choo, Celine Y L; Wong, Wai P; Chew, Shit F; Ip, Yuen K

2018-04-19

Giant clams live in nutrient-poor reef waters of the Indo-Pacific and rely on symbiotic dinoflagellates ( Symbiodinium spp., also known as zooxanthellae) for nutrients. As the symbionts are nitrogen deficient, the host clam has to absorb exogenous nitrogen and supply it to them. This study aimed to demonstrate light-enhanced urea absorption in the fluted giant clam, Tridacna squamosa , and to clone and characterize the urea active transporter DUR3-like from its ctenidium (gill). The results indicate that T. squamosa absorbs exogenous urea, and the rate of urea uptake in the light was significantly higher than that in darkness. The DUR3-like coding sequence obtained from its ctenidium comprised 2346 bp, encoding a protein of 782 amino acids and 87.0 kDa. DUR3-like was expressed strongly in the ctenidium, outer mantle and kidney. Twelve hours of exposure to light had no significant effect on the transcript level of ctenidial DUR3-like However, between 3 and 12 h of light exposure, DUR3-like protein abundance increased progressively in the ctenidium, and became significantly greater than that in the control at 12 h. DUR3-like had an apical localization in the epithelia of the ctenidial filaments and tertiary water channels. Taken together, these results indicate that DUR3-like might participate in light-enhanced urea absorption in the ctenidium of T. squamosa When made available to the symbiotic zooxanthellae that are known to possess urease, the absorbed urea can be metabolized to NH 3 and CO 2 to support amino acid synthesis and photosynthesis, respectively, during insolation. © 2018. Published by The Company of Biologists Ltd.

Aerosol Production and Growth in the Upper Troposphere over the Amazon Forest Observed during ACRIDICON-CHUVA

NASA Astrophysics Data System (ADS)

Andreae, M. O.; Afchine, A.; Albrecht, R. I.; Artaxo, P.; Borrmann, S.; Cecchini, M. A.; Costa, A.; Fütterer, D.; Järvinen, E.; Klimach, T.; Konemann, T.; Kraemer, M.; Machado, L.; Mertes, S.; Pöhlker, C.; Pöhlker, M. L.; Poeschl, U.; Sauer, D. N.; Schnaiter, M.; Schneider, J.; Schulz, C.; Spanu, A.; Walser, A.; Wang, J.; Weinzierl, B.; Wendisch, M.

2016-12-01

Observations during ACRIDICON-CHUVA showed high aerosol concentrations in the upper troposphere (UT) over the Amazon Basin, with aerosol number concentrations after normalization to STP often exceeding those in the boundary layer (BL) by one or two orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA (Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems) on the German research aircraft HALO. The campaign took place over the Amazon Basin in September/October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were consistently observed on all flights, using several aerosol metrics, including condensation nuclei (CN), cloud condensation nuclei (CCN), and chemical species mass concentrations. These UT aerosols were different in their composition and size distribution from the aerosol in the BL, making convective transport of particles unlikely as a source. The regions in the immediate outflow of deep convective clouds were depleted in aerosol particles, whereas dramatically enhanced small (<90 nm diameter) aerosol number concentrations were found in UT regions that had experienced outflow from deep convection in the preceding 24-48 hours. We also found elevated concentrations of larger (>90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest that aerosol production takes place in the UT from volatile material brought up by deep convection, which is converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol may be a source of particles to the BL, where they increase in size by the condensation of biogenic volatile organic carbon (BVOC) oxidation products. This may be an important source of aerosol particles in the Amazonian BL, where aerosol nucleation and new particle formation has not been observed. We propose that this may have been the dominant process supplying secondary aerosols in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles.

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

Rapoport, J.; Abuful, A.; Chaimovitz, C.

Urea is actively transported inwardly (J{sub i}) across the skin of the green toad Bufo viridis. J{sub i} is markedly enhanced in toads adapted to hypertonic saline. The authors studied urea transport across the skin of Bufo viridis under a variety of experimental conditions, including treatment with amiloride and phloretin, agents that inhibit urea permeability in the bladder of Bufo marinus. Amiloride (10{sup {minus}4} M) significantly inhibited J{sub i} in both adapted and unadapted animals and was unaffected by removal of sodium from the external medium. Phloretin (10{sup {minus}4} M) significantly inhibited J{sub i} in adapted animals by 23-46%; theremore » was also a reduction in J{sub i} in unadapted toads at 10{sup {minus}4} and 5 {times} 10{sup {minus}4} M phloretin. A dose-response study revealed that the concentration of phloretin causing half-maximal inhibition (K{sub {1/2}}) was 5 {times} 10{sup {minus}4} M for adapted animals. J{sub i} was unaffected by the substitution of sucrose for Ringer solution or by ouabain. They conclude (1) the process of adaptation appears to involve an increase in the number of amiloride- and phloretin-inhibitable urea transport sites in the skin, with a possible increase in the affinity of the sites for phloretin; (2) the adapted skin resembles the Bufo marinus urinary bladder with respect to amiloride and phloretin-inhibitable sites; (3) they confirm earlier observations that J{sub i} is independent of sodium transport.« less

Role of Urea-Aromatic Stacking Interactions in Stabilizing the Aromatic Residues of the Protein in Urea-Induced Denatured State.

PubMed

Goyal, Siddharth; Chattopadhyay, Aditya; Kasavajhala, Koushik; Priyakumar, U Deva

2017-10-25

A delicate balance of different types of intramolecular interactions makes the folded states of proteins marginally more stable than the unfolded states. Experiments use thermal, chemical, or mechanical stress to perturb the folding equilibrium for examining protein stability and the protein folding process. Elucidation of the mechanism by which chemical denaturants unfold proteins is crucial; this study explores the nature of urea-aromatic interactions relevant in urea-assisted protein denaturation. Free energy profiles corresponding to the unfolding of Trp-cage miniprotein in the presence and absence of urea at three different temperatures demonstrate the distortion of the hydrophobic core to be a crucial step. Exposure of the Trp6 residue to the solvent is found to be favored in the presence of urea. Previous experiments showed that urea has a high affinity for aromatic groups of proteins. We show here that this is due to the remarkable ability of urea to form stacking and NH-π interactions with aromatic groups of proteins. Urea-nucleobase stacking interactions have been shown to be crucial in urea-assisted RNA unfolding. Examination of these interactions using microsecond-long unrestrained simulations shows that urea-aromatic stacking interactions are stabilizing and long lasting. Further MD simulations, thermodynamic integration, and quantum mechanical calculations on aromatic model systems reveal that such interactions are possible for all the aromatic amino acid side-chains. Finally, we validate the ubiquitous nature of urea-aromatic stacking interactions by analyzing experimental structures of urea transporters and proteins crystallized in the presence of urea or urea derivatives.

Variations of GHGs from the lower-troposphere to the UT/LS revealed by two Japanese regular aircraft observation programs

NASA Astrophysics Data System (ADS)

Niwa, Yosuke; Machida, Toshinobu; Sawa, Yousuke; Tsuboi, Kazuhiro; Matsueda, Hidekazu; Imasu, Ryoichi

2014-05-01

A Japan-centered observation network consisting of two regular aircraft programs have revealed the greenhouse gases variations from the lower-troposphere to the upper-troposphere/lower-stratosphere (UT/LS) regions. In the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project, in-situ continuous measurement equipment (CME) onboard commercial passenger aircraft world-widely observes CO2 profiles in vertical over tens of airports and in horizontal in the UT/LS regions. The CONTRAIL-CME has revealed three-dimensional structure of the global CO2 distribution and has exposed significant inter-hemispheric transport of CO2 through the upper-troposphere. In inverse modeling, the CME data have provided strong constraints on CO2 flux estimation especially for the Asian tropics. Automatic flask air sampling equipment (ASE) is also onboard the CONTRAIL aircraft and has been observing CO2 mixing ratios as well as those of methane, carbon monoxide, nitrous oxide and other trace species in the upper-troposphere between Japan and Australia. The observation period of the ASE has reached 20 years. In recent years, the ASE program has extended to the northern subarctic UT/LS region and has given an insight of transport mechanisms in the UT/LS by observing seasonal GHGs variations. In the other aircraft observation program by Japan Meteorological Agency, variations of GHGs have been observed by flask-sampling onboard a C-130H aircraft horizontally in the mid-troposphere over the western North Pacific as well as vertically over Minamitorishima-Island. The C-130H aircraft has persistently observed high mixing ratios of CH4 in the mid-troposphere, which seems to be originated from fossil fuel combustion throughout the year as well as from biogenic sources during summer in the Asian regions. Those above aircraft observation programs have a significant role for constraining GHGs flux estimates by filling the data gap of the existing surface measurement network specifically in the regions of Asia and the western North Pacific.

Architecture of vasa recta in the renal inner medulla of the desert rodent Dipodomys merriami: potential impact on the urine concentrating mechanism.

PubMed

Issaian, Tadeh; Urity, Vinoo B; Dantzler, William H; Pannabecker, Thomas L

2012-10-01

We hypothesize that the inner medulla of the kangaroo rat Dipodomys merriami, a desert rodent that concentrates its urine to over 6,000 mosmol/kg H(2)O, provides unique examples of architectural features necessary for production of highly concentrated urine. To investigate this architecture, inner medullary vascular segments in the outer inner medulla were assessed with immunofluorescence and digital reconstructions from tissue sections. Descending vasa recta (DVR) expressing the urea transporter UT-B and the water channel aquaporin 1 lie at the periphery of groups of collecting ducts (CDs) that coalesce in their descent through the inner medulla. Ascending vasa recta (AVR) lie inside and outside groups of CDs. DVR peel away from vascular bundles at a uniform rate as they descend the inner medulla, and feed into networks of AVR that are associated with organized clusters of CDs. These AVR form interstitial nodal spaces, with each space composed of a single CD, two AVR, and one or more ascending thin limbs or prebend segments, an architecture that may lead to solute compartmentation and fluid fluxes essential to the urine concentrating mechanism. Although we have identified several apparent differences, the tubulovascular architecture of the kangaroo rat inner medulla is remarkably similar to that of the Munich Wistar rat at the level of our analyses. More detailed studies are required for identifying interspecies functional differences.

Comparative physiology and architecture associated with the mammalian urine concentrating mechanism: role of inner medullary water and urea transport pathways in the rodent medulla.

PubMed

Pannabecker, Thomas L

2013-04-01

Comparative studies of renal structure and function have potential to provide insights into the urine-concentrating mechanism of the mammalian kidney. This review focuses on the tubular transport pathways for water and urea that play key roles in fluid and solute movements between various compartments of the rodent renal inner medulla. Information on aquaporin water channel and urea transporter expression has increased our understanding of functional segmentation of medullary thin limbs of Henle's loops, collecting ducts, and vasa recta. A more complete understanding of membrane transporters and medullary architecture has identified new and potentially significant interactions between these structures and the interstitium. These interactions are now being introduced into our concept of how the inner medullary urine-concentrating mechanism works. A variety of regulatory pathways lead directly or indirectly to variable patterns of fluid and solute movements among the interstitial and tissue compartments. Animals with the ability to produce highly concentrated urine, such as desert species, are considered to exemplify tubular structure and function that optimize urine concentration. These species may provide unique insights into the urine-concentrating process.(1)

Comparative physiology and architecture associated with the mammalian urine concentrating mechanism: role of inner medullary water and urea transport pathways in the rodent medulla

PubMed Central

2013-01-01

Comparative studies of renal structure and function have potential to provide insights into the urine-concentrating mechanism of the mammalian kidney. This review focuses on the tubular transport pathways for water and urea that play key roles in fluid and solute movements between various compartments of the rodent renal inner medulla. Information on aquaporin water channel and urea transporter expression has increased our understanding of functional segmentation of medullary thin limbs of Henle's loops, collecting ducts, and vasa recta. A more complete understanding of membrane transporters and medullary architecture has identified new and potentially significant interactions between these structures and the interstitium. These interactions are now being introduced into our concept of how the inner medullary urine-concentrating mechanism works. A variety of regulatory pathways lead directly or indirectly to variable patterns of fluid and solute movements among the interstitial and tissue compartments. Animals with the ability to produce highly concentrated urine, such as desert species, are considered to exemplify tubular structure and function that optimize urine concentration. These species may provide unique insights into the urine-concentrating process.1 PMID:23364530

Atomistic insights into deep eutectic electrolytes: the influence of urea on the electrolyte salt LiTFSI in view of electrochemical applications.

PubMed

Lesch, Volker; Heuer, Andreas; Rad, Babak R; Winter, Martin; Smiatek, Jens

2016-10-19

The influence of urea on the conducting salt lithium bis-(trifluoromethanesulfonyl)-imide (LiTFSI) in terms of lithium ion coordination numbers and lithium ion transport properties is studied via atomistic molecular dynamics simulations. Our results indicate that the presence of urea favors the formation of a deep eutectic electrolyte with pronounced ion conductivities which can be explained by a competition between urea and TFSI in occupying the first coordination shell around lithium ions. All simulation findings verify that high urea concentrations lead to a significant increase of ionic diffusivities and an occurrence of relatively high lithium transference numbers in good agreement with experimental results. The outcomes of our study point at the possible application of deep eutectic electrolytes as ion conducting materials in lithium ion batteries.

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

NASA Astrophysics Data System (ADS)

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

2018-01-01

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles (< 90 nm diameter) were found in UT regions that had experienced outflow from deep convection in the preceding 5-72 h. We also found elevated concentrations of larger (> 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol can be a source of particles to the PBL, where they increase in size by the condensation of biogenic volatile organic compound (BVOC) oxidation products. This may be an important source of aerosol particles for the Amazonian PBL, where aerosol nucleation and new particle formation have not been observed. We propose that this may have been the dominant process supplying secondary aerosol particles in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles.

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

DOE PAGES

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; ...

2018-01-25

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (globalmore » precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September–October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles (< 90 nm diameter) were found in UT regions that had experienced outflow from deep convection in the preceding 5–72 h. We also found elevated concentrations of larger (> 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol can be a source of particles to the PBL, where they increase in size by the condensation of biogenic volatile organic compound (BVOC) oxidation products. This may be an important source of aerosol particles for the Amazonian PBL, where aerosol nucleation and new particle formation have not been observed. We propose that this may have been the dominant process supplying secondary aerosol particles in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles.« less

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

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

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (globalmore » precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September–October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles (< 90 nm diameter) were found in UT regions that had experienced outflow from deep convection in the preceding 5–72 h. We also found elevated concentrations of larger (> 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol can be a source of particles to the PBL, where they increase in size by the condensation of biogenic volatile organic compound (BVOC) oxidation products. This may be an important source of aerosol particles for the Amazonian PBL, where aerosol nucleation and new particle formation have not been observed. We propose that this may have been the dominant process supplying secondary aerosol particles in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles.« less

Urea inhibits NaK2Cl cotransport in human erythrocytes.

PubMed Central

Lim, J; Gasson, C; Kaji, D M

1995-01-01

We examined the effect of urea on NaK2Cl cotransport in human erythrocytes. In erythrocytes from nine normal subjects, the addition of 45 mM urea, a concentration commonly encountered in uremic subjects, inhibited NaK2Cl cotransport by 33 +/- 7%. Urea inhibited NaK2Cl cotransport reversibly, and in a concentration-dependent fashion with half-maximal inhibition at 63 +/- 10 mM. Acute cell shrinkage increased, and acute cell swelling decreased NaK2Cl cotransport in human erythrocytes. Okadaic acid (OA), a specific inhibitor of protein phosphatase 1 and 2A, increased NaK2Cl cotransport by nearly 80%, suggesting an important role for these phosphatases in the regulation of NaK2Cl cotransport. Urea inhibited bumetanide-sensitive K influx even when protein phosphatases were inhibited with OA, suggesting that urea acted by inhibiting a kinase. In cells subjected to shrinking and OA pretreatment, maneuvers expected to increase the net phosphorylation, urea inhibited cotransport only minimally, suggesting that urea acted by causing a net dephosphorylation of the cotransport protein, or some key regulatory protein. The finding that concentrations of urea found in uremic subjects inhibited NaK2Cl cotransport, a widespread transport pathway with important physiological functions, suggests that urea is not only a marker for accumulation of other uremic toxins, but may be a significant uremic toxin itself. PMID:7593597

Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation

PubMed Central

2011-01-01

Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH4+ production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface. PMID:21943229

A Novel Anoxic Pathway for Urea and Cyanate in Marine Oxygen Deficient Zones Revealed by Combined Microbiological and Biogeochemical Tools

NASA Astrophysics Data System (ADS)

Widner, B.; Fuchsman, C. A.; Babbin, A. R.; Ji, Q.; Mulholland, M. R.

2016-02-01

Urea and cyanate are reduced nitrogen compounds that can serve as nitrogen and carbon sources for marine microbes, and cyanate forms from decomposition of urea. Some marine bacteria, including cyanobacteria, possess genes encoding an ABC-type cyanate transporter and an intracellular cyanate hydratase, and genes for urea uptake and assimilation are widespread. To investigate cyanate distribution and availability in the ocean, we recently developed a nanomolar cyanate assay specific to seawater. In an oxygenated water column, urea and cyanate concentrations are generally low in surface waters and exhibit a concentration maximum near the base of the euphotic zone likely due to production from organic matter degradation. Below the euphotic zone, urea and cyanate concentrations decrease, likely due to oxidation reactions. It has been suggested that simple organic nitrogen compounds may support anaerobic ammonium oxidation (anammox) in oxygen deficient zones (ODZs). We mapped urea and cyanate distributions and used stable isotope-labeled urea and cyanate to measure their potential support of anammox and their uptake within the Eastern Tropical North and South Pacific ODZs. We also employed metagenomic techniques to determine the abundance and distribution of genes for the uptake and assimilation of urea and cyanate. The combined data indicate that, in ODZs, urea is used primarily as a nitrogen source while cyanate is used as both a nitrogen source and to generate energy.

Wind ripples in low density atmospheres

NASA Technical Reports Server (NTRS)

Miller, J. S.; Marshall, J. R.; Greeley, R.

1987-01-01

The effect of varying fluid density (rho) on particle transport was examined by conducting tests at atmospheric pressures between 1 and 0.004 bar in the Martian Surface Wind Tunnel (MARSWIT). This study specifically concerns the effect of varying rho on the character of wind ripples, and elicits information concerning generalized ripple models as well as specific geological circumstances for ripple formation such as those prevailing on Mars. Tests were conducted primarily with 95 micron quartz sand, and for each atmospheric pressure chosen, tests were conducted at two freestream wind speeds: 1.1 U*(t) and 1.5 U*(t), where U*(t) is saltation threshold. Preliminary analysis of the data suggests: (1) ballistic ripple wavelength is not at variance with model predictions; (2) an atmospheric pressure of approximately 0.2 bar could represent a discontinuity in ripple behavior; and (4) ripple formation on Mars may not be readily predicted by extrapolation of terrestrial observations.

Effect of pyrazinamide and probenecid on peritoneal urate transport kinetics during continuous ambulatory peritoneal dialysis.

PubMed

Spaia, S; Magoula, I; Tsapas, G; Vayonas, G

2000-01-01

We administered pyrazinamide (PZA) and probenecid (PB) --two well-known modulators of urate transport via the proximal tubules - to evaluate their impact on urate transport through the peritoneal membrane and to clarify mechanisms affecting peritoneal transport. A continuous ambulatory peritoneal dialysis (CAPD) unit in 2nd Hospital of IKA (Social Services Institute), Greece. In 20 stable CAPD patients, on the study day, a 4-hour, 2-L, 1.36% glucose exchange was performed (control exchange). Pyrazinamide 3 g was given orally and another identical exchange was performed (study exchange). The same protocol was repeated with 2 g PB. KtN, peritoneal clearances of urea, creatinine, and urate for each exchange, and mass transfer area coefficients (MTAC) for the three solutes and their dialysate-to-plasma concentration (D/P) ratios were used to estimate peritoneal transport. Administration of PZA resulted in decreased clearances and MTAC values for the three solutes. The D/P ratio decreased significantly only for urate, indicating a more intense influence of PZA on urate. After PB administration, clearances of urea, creatinine, and urate were increased. MTAC and DIP ratio increased significantly only for urate (p < 0.05), demonstrating an action similar to that exerted on renal tubules. These findings provide evidence that unrestricted diffusion is not the only transport mechanism in the case of urate, and demonstrate the existence of an active mechanism in peritoneal urate transport with a reabsorptive and, probably, a secretive component that resembles that of renal tubule urate transport. Attention should be given in the case of CAPD patients undergoing antituberculous (PZA) treatment: it might have a negative impact on urea, creatinine, and urate peritoneal transport rates.

Application of a data assimilation method via an ensemble Kalman filter to reactive urea hydrolysis transport modeling

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

Juxiu Tong; Bill X. Hu; Hai Huang

2014-03-01

With growing importance of water resources in the world, remediations of anthropogenic contaminations due to reactive solute transport become even more important. A good understanding of reactive rate parameters such as kinetic parameters is the key to accurately predicting reactive solute transport processes and designing corresponding remediation schemes. For modeling reactive solute transport, it is very difficult to estimate chemical reaction rate parameters due to complex processes of chemical reactions and limited available data. To find a method to get the reactive rate parameters for the reactive urea hydrolysis transport modeling and obtain more accurate prediction for the chemical concentrations,more » we developed a data assimilation method based on an ensemble Kalman filter (EnKF) method to calibrate reactive rate parameters for modeling urea hydrolysis transport in a synthetic one-dimensional column at laboratory scale and to update modeling prediction. We applied a constrained EnKF method to pose constraints to the updated reactive rate parameters and the predicted solute concentrations based on their physical meanings after the data assimilation calibration. From the study results we concluded that we could efficiently improve the chemical reactive rate parameters with the data assimilation method via the EnKF, and at the same time we could improve solute concentration prediction. The more data we assimilated, the more accurate the reactive rate parameters and concentration prediction. The filter divergence problem was also solved in this study.« less

Effect of lycopene against cisplatin-induced acute renal injury in rats: organic anion and cation transporters evaluation.

PubMed

Erman, Fazilet; Tuzcu, Mehmet; Orhan, Cemal; Sahin, Nurhan; Sahin, Kazim

2014-04-01

In the present study, we investigated the effects of lycopene on the expression of organic anion transporters (OATs), organic cation transporters (OCTs), and multidrug resistance-associated proteins (MRPs) of cisplatin-induced nephrotoxicity in rats. Twenty-eight 8-week-old Wistar rats were divided into four groups: control, lycopene-treated (6 mg/kg BW by oral gavage), cisplatin-treated (7 mg/kg BW, IP), and lycopene in combination with cisplatin-treated groups. In the presence of cisplatin, serum urea nitrogen (urea-N) (48.5 vs. 124.3 mg/dl) and creatinine (0.29 vs. 1.37 mg/dl) levels and the kidney efflux transporters MRP2 and MRP4 levels were significantly increased, whereas OAT1, OAT3, OCT1, and OCT2 levels in kidney were decreased in the treated rats compared with normal control rats. However, administration of lycopene in combination with cisplatin resulted in a reduction in the serum urea-N (124.3 vs. 62.4) and creatinine (1.37 vs. 0.40) levels and the kidney efflux transporters MRP2 and MRP4 proteins in the kidneys. Administration of lycopene to acute renal injury-induced rats largely upregulated the organic anion transporters (OAT1 and 3) and organic cation transporters (OCT1 and 2) to decrease the side effects of cisplatin. The present study suggests that lycopene synergizes with its nephroprotective effect against cisplatin-induced acute kidney injury in rats.

Influence of land management and hydrology on urea fate and transport within a Coastal Plain watershed dominated by intensive poultry agriculture

USDA-ARS?s Scientific Manuscript database

Increasing nutrient loads delivered from the landscape to coastal ecosystems has widely been recognized as a major contributor to coastal eutrophication and as a driver of the escalation of harmful algal blooms (HABs). Urea, a form of organic nitrogen, is a common nutrient found in fertilizers, manu...

Watershed level examination of urea fate and transport and the production of the biotoxin domoic acid

USDA-ARS?s Scientific Manuscript database

The Chesapeake Bay, the largest estuary in the world, is an important source of many fish and shellfish. The safety of these species as a food source is currently at risk due to nutrient pollution. Urea, a form of organic nitrogen found in manure and fertilizer, is increasing in usage within the Ba...

The transport kinetics and selectivity of HpUreI, the urea channel from Helicobacter pylori†

PubMed Central

Gray, Lawrence R; Gu, Sean X; Quick, Matthias; Khademi, Shahram

2017-01-01

Helicobacter pylori’s unique ability to colonize and survive in the acidic environment of the stomach is critically dependent on uptake of urea through the urea channel, HpUreI. Hence, HpUreI may represent a promising target for the development of specific drugs against this human pathogen. To obtain insight into the structure/function relationship of this channel, we have developed conditions for the high-yield expression and purification of stable recombinant HpUreI that allowed its detailed kinetic characterization in solubilized form and reconstituted into liposomes. Detergent-solubilized HpUreI forms homo-trimer, as determined by chemical cross-linking. Urea dissociation kinetics of purified HpUreI were determined by means of the scintillation proximity assay (SPA), whereas urea efflux was measured in HpUreI-containing proteoliposomes using stopped-flow spectrometry to determine the kinetics and selectivity of the urea channel. The kinetic analyses revealed that urea conduction in HpUreI is pH sensitive and saturable with a half-saturation concentration (or K0.5) of ~163 mM. Binding of urea by HpUreI was increased at lower pH; however, the apparent affinity of urea binding (~150 mM) was not significantly pH dependent. The solute selectivity analysis indicated that HpUreI is highly selective for urea and hydroxyurea. Removing either amino group of urea molecules diminishes their permeability through HpUreI. Similar to urea conduction, water diffusion through HpUreI is pH-dependent with low water permeability at neutral pH. PMID:21877689

Aerosol Enhancements in the Upper Troposphere Over The Amazon Forest: Do Amazonian Clouds Produce Aerosols?

NASA Astrophysics Data System (ADS)

Andreae, M. O.; Afchine, A.; Albrecht, R. I.; Artaxo, P.; Borrmann, S.; Cecchini, M. A.; Costa, A.; Dollner, M.; Fütterer, D.; Järvinen, E.; Klimach, T.; Konemann, T.; Kraemer, M.; Krüger, M. L.; Machado, L.; Mertes, S.; Pöhlker, C.; Poeschl, U.; Sauer, D. N.; Schnaiter, M.; Schneider, J.; Schulz, C.; Spanu, A.; Walser, A.; Weinzierl, B.; Wendisch, M.

2015-12-01

The German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA (Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems) on the German research aircraft HALO took place over the Amazon Basin in September/October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with trace gases, aerosol particles, and atmospheric radiation. The aircraft was equipped with about 30 remote sensing and in-situ instruments for meteorological, trace gas, aerosol, cloud, precipitation, and solar radiation measurements. Fourteen research flights were conducted during this campaign. Observations during ACRIDICON-CHUVA showed high aerosol concentrations in the upper troposphere (UT) over the Amazon Basin, with concentrations after normalization to standard conditions often exceeding those in the boundary layer (BL). This behavior was consistent between several aerosol metrics, including condensation nuclei (CN), cloud condensation nuclei (CCN), and chemical species mass concentrations. These UT aerosols were different in their composition and size distribution from the aerosol in the BL, making convective transport of particles unlikely as a source. The regions in the immediate outflow of deep convective clouds were found to be depleted in aerosol particles, whereas enhanced aerosol number and mass concentrations were found in UT regions that had experienced outflow from deep convection in the preceding 24-48 hours. This suggests that aerosol production takes place in the UT based on volatile and condensable material brought up by deep convection. Subsequently, downward mixing and transport of upper tropospheric aerosol may be a source of particles to the BL, where they increase in size by the condensation of biogenic volatile organic carbon (BVOC) oxidation products. This may be an important source of aerosol particles in the Amazonian BL, where aerosol nucleation and new particle formation has not been observed.

Trusted Truck(R) II (phase A).

DOT National Transportation Integrated Search

2009-01-01

The Trusted Truck Program was initiated in 2003 as a joint effort by NTRCI, Volvo and UT. The vision of the Trusted Truck program is to develop a secure and "trusted" transport solution from pickup to delivery. The program's objective is to incre...

Most promising research : research peer exchange, August 16-17, 2011.

DOT National Transportation Integrated Search

2011-08-01

The Iowa Department of Transportation held a Research Peer Exchange on August 16-17, 2011 in Ames, Iowa. RAC members from Region 3 (Minnesota, Iowa, Missouri, Ohio) and the following states, Louisiana, Washington, Oregon, South Dakota, Arizona and Ut...

Fire Safety Aspects of Polymeric Materials. Volume 8. Land Transportation Vehicles

DTIC Science & Technology

1979-01-01

Resins and Urea - and Melamine - Formaldehyde Resins ," in: Kurylaand Papa (1973). 188 I RtftHfcNCES...ting furfuryl alcohol and an aldehyde — most frequently formaldehyde (Siegfried 1967). Urea is often used as a modifying agent. The resins are hardened... melamine / formaldehyde and phenol/formaldehye resins may find significant utility as a char resistant coating on factory coated wood. 73 /’ I

Center for Space Transportation and Applied Research Fifth Annual Technical Symposium Proceedings

NASA Technical Reports Server (NTRS)

1993-01-01

This Fifth Annual Technical Symposium, sponsored by the UT-Calspan Center for Space Transportation and Applied Research (CSTAR), is organized to provide an overview of the technical accomplishments of the Center's five Research and Technology focus areas during the past year. These areas include chemical propulsion, electric propulsion, commerical space transportation, computational methods, and laser materials processing. Papers in the area of artificial intelligence/expert systems are also presented.

First-Principles Molecular Dynamics Study of a Deep Eutectic Solvent: Choline Chloride/Urea and Its Mixture with Water

DOE PAGES

Fetisov, Evgenii O.; Harwood, David B.; Kuo, I-Feng William; ...

2017-12-07

First-principles molecular dynamics simulations in the canonical ensemble at temperatures of 333 and 363 K and at the corresponding experimental densities are carried out to investigate the behavior of the 1:2 choline chloride/urea (reline) deep eutectic solvent and its equimolar mixture with water. Analysis of atom–atom radial and spatial distribution functions and of the H-bond network reveals the microheterogeneous structure of these complex liquid mixtures. In neat reline, the structure is governed by strong H-bonds of the trans- and cis-H atoms of urea to the chloride ion. In hydrous reline, water competes for the anions, and the H atoms ofmore » urea have similar propensities to bond to the chloride ions and the O atoms of urea and water. Finally, the vibrational spectra exhibit relatively broad peaks reflecting the heterogeneity of the environment. Although the 100 ps trajectories allow only for a qualitative assessment of transport properties, the simulations indicate that water is more mobile than the other species and its addition also fosters faster motion of urea.« less

UT/LS chemistry and transport

DOT National Transportation Integrated Search

2008-01-25

This SSWP summarizes important results in key areas since the last major aircraft impacts assessment [IPCC 1999]. Significant progress has been made in the areas of: Measurements of emissions of chemi-ions, NOx, and trace organic species from aircraf...

Bacteria can mobilize nematode-trapping fungi to kill nematodes

PubMed Central

Wang, Xin; Li, Guo-Hong; Zou, Cheng-Gang; Ji, Xing-Lai; Liu, Tong; Zhao, Pei-Ji; Liang, Lian-Ming; Xu, Jian-Ping; An, Zhi-Qiang; Zheng, Xi; Qin, Yue-Ke; Tian, Meng-Qing; Xu, You-Yao; Ma, Yi-Cheng; Yu, Ze-Fen; Huang, Xiao-Wei; Liu, Shu-Qun; Niu, Xue-Mei; Yang, Jin-Kui; Huang, Ying; Zhang, Ke-Qin

2014-01-01

In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode–predatory form; this predacious form is characterized by formation of specialized cellular structures or ‘traps’. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator–prey interactions in prey defense mechanisms. PMID:25514608

Elevated O3 in Fresh and Aged Lightning-NOx Plumes Interacting with Biomass Burning Plumes over the Central U.S. during DC3 (Invited)

NASA Astrophysics Data System (ADS)

Huntrieser, H.; Lichtenstern, M.; Scheibe, M.; Aufmhoff, H.; Schlager, H.; Pucik, T.; Minikin, A.; Weinzierl, B.; Heimerl, K.; Fütterer, D.; Rappenglück, B.; Ackermann, L.; Pickering, K. E.; Cummings, K.; Barth, M. C.

2013-12-01

During the Deep Convective Clouds and Chemistry Experiment (DC3) in summer 2012 a variety of different thunderstorm systems were investigated over the Central U.S. by the DLR research aircraft Falcon together with the NCAR GV and NASA DC-8 aircraft. In addition, the complete DC3 field phase was characterized by a number of extended wildfires burning in the surroundings of the thunderstorms. Here we mainly focus on trace gas in situ measurements, such as NOx, CO, O3, CH4, SO2, NMHC, and a variety of aerosol measurements carried out by the Falcon in the fresh (~0-6 h) and aged (~12-24 h) anvil outflow at ~10-12 km altitude. It is well-known that thunderstorms modify the trace gas composition in the upper troposphere (UT) and may affect O3 mixing ratios, an important greenhouse gas in the UT. However, a complete picture of the different processes affecting the UT-O3 composition in vicinity of thunderstorms and its large-scale effects is still missing. From the DC3 data set we present an example of small-scale effects on the O3 composition in the anvil outflow, such as immediate O3 production by an aircraft-induced flash. But we also show how the efficient convective transport that extended over the whole updraft region may transport O3-poorer air masses from the, in general, rather unpolluted inflow region (with regard to anthropogenic emissions) over the Central U.S. directly to the UT. However, in a few cases enhanced O3 mixing ratios were observed in the anvil outflow attributed to different chemical and dynamical processes. In the two most powerful convective systems, an intense MCS over Missouri/Arkansas and a supercell over Texas, extended biomass burning (BB) plumes from New Mexico interacted with the thunderstorms. Ozone production was obvious in the BB plumes transported mainly in the lower troposphere at ~2-5 km altitude (ΔO3/ΔCO=0.1). However, if these air masses affected by BB emissions (containing high amounts of O3 precursors such as CH4 and NMHC) were ingested into the surrounding thunderstorms (with high HOx and NOx) and transported to the UT region, the ΔO3/ΔCO slope increased dramatically to values up to ~0.6-2.5. In addition to enhanced O3 production rates in thunderstorm outflows interacting with BB plumes, the pronounced downward mixing of O3-rich air mass from the stratosphere down to 8 km was observed in an aged anvil outflow from a squall line active over Colorado which was advected to Kansas the day after. Overall, from the local DC3 Falcon measurements the effect of downward mixing of O3-rich stratospheric air masses seems to cause the largest increase in O3 mixing ratios in the aged anvil outflow.

Metformin improves urine concentration in rodents with nephrogenic diabetes insipidus

PubMed Central

Efe, Orhan; Klein, Janet D.; LaRocque, Lauren M.; Ren, Huiwen; Sands, Jeff M.

2016-01-01

Urine concentration is regulated by vasopressin. Congenital nephrogenic diabetes insipidus (NDI) is caused by vasopressin type 2 receptor (V2R) mutations. We studied whether metformin could improve urine concentration in rodent models of congenital NDI by stimulating AMPK. To block the V2R in rats, tolvaptan (10 mg/kg/d) was given by oral gavage with or without metformin (800 mg/kg/d). Control rats received vehicle with or without metformin. Tamoxifen-induced V2R KO mice were given metformin (600 mg/kg) or vehicle twice daily. Urine osmolality in tolvaptan-treated rats (1,303 ± 126 mOsM) was restored to control levels by metformin (2,335 ± 273 mOsM) within 3 days and was sustained for up to 10 days. Metformin increased protein abundance of inner medullary urea transporter UT-A1 by 61% and aquaporin 2 (AQP2) by 44% in tolvaptan-treated rats, and immunohistochemistry showed increased membrane accumulation of AQP2 with acute and chronic AMPK stimulation. Outer medullary Na+-K+-2Cl– cotransporter 2 (NKCC2) abundance increased (117%) with AMPK stimulation in control rats but not in V2R-blocked rats. Metformin increased V2R KO mouse urine osmolality within 3 hours, and the increase persisted for up to 12 hours. Metformin increased AQP2 in the V2R KO mice similar to the tolvaptan-treated rats. These results indicate that AMPK activators, such as metformin, might provide a promising treatment for congenital NDI. PMID:27478876

Inborn Errors of Metabolism with Hyperammonemia: Urea Cycle Defects and Related Disorders.

PubMed

Summar, Marshall L; Mew, Nicholas Ah

2018-04-01

The urea cycle disorders are a group of inherited biochemical diseases caused by a complete or partial deficiency of any one of the enzymes or transport proteins required to convert toxic ammonia into urea and to produce arginine and citrulline. The clinical manifestations of these disorders are mostly the result of acute or chronic hyperammonemia, which affects the central nervous system. Affected individuals can also develop hepatic dysfunction. These disorders can present at any age from the immediate newborn to later in life. Early diagnosis and treatment are key to improving outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Nonpeptidic urotensin-II receptor antagonists I: in vitro pharmacological characterization of SB-706375

PubMed Central

Douglas, Stephen A; Behm, David J; Aiyar, Nambi V; Naselsky, Diane; Disa, Jyoti; Brooks, David P; Ohlstein, Eliot H; Gleason, John G; Sarau, Henry M; Foley, James J; Buckley, Peter T; Schmidt, Dulcie B; Wixted, William E; Widdowson, Katherine; Riley, Graham; Jin, Jian; Gallagher, Timothy F; Schmidt, Stanley J; Ridgers, Lance; Christmann, Lisa T; Keenan, Richard M; Knight, Steven D; Dhanak, Dashyant

2005-01-01

SB-706375 potently inhibited [125I]hU-II binding to both mammalian recombinant and ‘native' UT receptors (Ki 4.7±1.5 to 20.7±3.6 nM at rodent, feline and primate recombinant UT receptors and Ki 5.4±0.4 nM at the endogenous UT receptor in SJRH30 cells). Prior exposure to SB-706375 (1 μM, 30 min) did not alter [125I]hU-II binding affinity or density in recombinant cells (KD 3.1±0.4 vs 5.8±0.9 nM and Bmax 3.1±1.0 vs 2.8±0.8 pmol mg−1) consistent with a reversible mode of action. The novel, nonpeptidic radioligand [3H]SB-657510, a close analogue of SB-706375, bound to the monkey UT receptor (KD 2.6±0.4 nM, Bmax 0.86±0.12 pmol mg−1) in a manner that was inhibited by both U-II isopeptides and SB-706375 (Ki 4.6±1.4 to 17.6±5.4 nM) consistent with the sulphonamides and native U-II ligands sharing a common UT receptor binding domain. SB-706375 was a potent, competitive hU-II antagonist across species with pKb 7.29–8.00 in HEK293-UT receptor cells (inhibition of [Ca2+]i-mobilization) and pKb 7.47 in rat isolated aorta (inhibition of contraction). SB-706375 also reversed tone established in the rat aorta by prior exposure to hU-II (Kapp∼20 nM). SB-706375 was a selective U-II antagonist with ⩾100-fold selectivity for the human UT receptor compared to 86 distinct receptors, ion channels, enzymes, transporters and nuclear hormones (Ki/IC50>1 μM). Accordingly, the contractile responses induced in isolated aortae by KCl, phenylephrine, angiotensin II and endothelin-1 were unaltered by SB-706375 (1 μM). In summary, SB-706375 is a high-affinity, surmountable, reversible and selective nonpeptide UT receptor antagonist with cross-species activity that will assist in delineating the pathophysiological actions of U-II in mammals. PMID:15852036

Roughness configuration matters for aeolian sediment flux

USDA-ARS?s Scientific Manuscript database

The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of s...

Characterizing UT/LS O3 from Global Ozonesonde Profiles Using a Clustering Technique and Meteorological Reanalyses

NASA Astrophysics Data System (ADS)

Stauffer, R. M.; Thompson, A. M.

2017-12-01

Previous studies employing the self-organizing map (SOM) clustering technique to US ozonesonde data proved valuable for quantifying UT/LS O3 variability, and linking meteorological and chemical drivers to the shape of the ozone (O3) profile from the troposphere to the lower stratosphere. Focus has thus far been limited to specific geographical regions, but SOM has demonstrated the advantages of clustering over monthly climatological O3 averages, which mask day-to-day variability in the O3 profile and the correspondence between O3 and meteorology. We expand SOM to a global set of ozonesonde profiles, mostly from WOUDC, spanning 1980-present from 30 sites to evaluate global O3 climatologies and quantify links to geophysical processes for various meteorological regimes. Four clusters of O3 mixing ratio profiles are generated for each site, which show dominant profile shapes that correspond to site latitude. Offsets among O3 profile clusters and monthly O3 climatologies are 100s of ppbv in the UT/LS at higher latitude sites with active dynamics. Examination of meteorological reanalyses reveals a clear relationship among SOM clusters and covarying meteorological fields (geopotential height, potential vorticity, and tropopause height) for most sites. Tropical SOM clusters show marked dependence on velocity potential anomalies calculated from reanalysis winds, with low UT/LS O3 amounts corresponding to enhanced upper-level divergence, and vice versa. In addition to creating SOM cluster-based O3 climatologies, these results are meant to inform future approaches to validation of chemical transport models and satellite retrievals, which often struggle in the UT/LS region.

Ground Penetrating Radar for Measuring Pavement Layer Thickness

DOT National Transportation Integrated Search

2013-01-01

The Utah Department of Transportation (UDOT) implemented and evaluated an advanced traffic signal timing strategy just outside Salt Lake City on the Riverdale Road corridor in Ogden, UT. The objective of the project was to make UDOTs traffic signa...

Hydroponics versus field lysimeter studies of urea, ammonium and nitrate uptake by oilseed rape (Brassica napus L.).

PubMed

Arkoun, Mustapha; Sarda, Xavier; Jannin, Laëtitia; Laîné, Philippe; Etienne, Philippe; Garcia-Mina, José-Maria; Yvin, Jean-Claude; Ourry, Alain

2012-09-01

N-fertilizer use efficiencies are affected by their chemical composition and suffer from potential N-losses by volatilization. In a field lysimeter experiment, (15)N-labelled fertilizers were used to follow N uptake by Brassica napus L. and assess N-losses by volatilization. Use of urea with NBPT (urease inhibitor) showed the best efficiency with the lowest N losses (8% of N applied compared with 25% with urea alone). Plants receiving ammonium sulphate, had similar yield achieved through a better N mobilization from vegetative tissues to the seeds, despite a lower N uptake resulting from a higher volatilization (43% of applied N). Amounts of (15)N in the plant were also higher when plants were fertilized with ammonium nitrate but N-losses reached 23% of applied N. In parallel, hydroponic experiments showed a deleterious effect of ammonium and urea on the growth of oilseed rape. This was alleviated by the nitrate supply, which was preferentially taken up. B. napus was also characterized by a very low potential for urea uptake. BnDUR3 and BnAMT1, encoding urea and ammonium transporters, were up-regulated by urea, suggesting that urea-grown plants suffered from nitrogen deficiency. The results also suggested a role for nitrate as a signal for the expression of BnDUR3, in addition to its role as a major nutrient. Overall, the results of the hydroponic study showed that urea itself does not contribute significantly to the N nutrition of oilseed rape. Moreover, it may contribute indirectly since a better use efficiency for urea fertilizer, which was further increased by the application of a urease inhibitor, was observed in the lysimeter study.

Role of urea on recombinant Apo A-I stability and its utilization in anion exchange chromatography.

PubMed

Angarita, Monica; Arosio, Paolo; Müller-Späth, Thomas; Baur, Daniel; Falkenstein, Roberto; Kuhne, Wolfgang; Morbidelli, Massimo

2014-08-08

Apolipoprotein A-I (Apo A-I) is an important lipid-binding protein involved in the transport and metabolism of cholesterol. High protein purity, in particular with respect to endotoxins is required for therapeutic applications. The use of urea during the purification process of recombinant Apo A-I produced in Escherichia coli has been suggested so as to provide high endotoxin clearance. In this work, we show that urea can be used as a sole modifier during the ion exchange chromatographic purification of Apo A-I and we investigate the molecular mechanism of elution by correlating the effect of urea on self-association, conformation and adsorption equilibrium properties of a modified model Apo A-I. In the absence of urea the protein was found to be present as a population of oligomers represented mainly by trimers, hexamers and nonamers. The addition of urea induced oligomer dissociation and protein structure unfolding. We correlated the changes in protein association and conformation with variations of the adsorption equilibrium of the protein on a strong anion exchanger. It was confirmed that the adsorption isotherms, described by a Langmuir model, were dependent on both protein and urea concentrations. Monomers, observed at low urea concentration (0.5M), were characterized by larger binding affinity and adsorption capacity compared to both protein oligomers (0M) and unfolded monomers (2-8M). The reduction of both the binding strength and maximum adsorption capacity at urea concentrations larger than 0.5M explains the ability of urea of inducing elution of the protein from the ion exchange resin. The dissociation of the protein complexes occurring during the elution could likely be the origin of the effective clearance of endotoxins originally trapped inside the oligomers. Copyright © 2014 Elsevier B.V. All rights reserved.

The urea cycle disorders.

PubMed

Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

2014-07-01

The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Particulate sulfur in the upper troposphere and lowermost stratosphere - sources and climate forcing

NASA Astrophysics Data System (ADS)

Martinsson, Bengt G.; Friberg, Johan; Sandvik, Oscar S.; Hermann, Markus; van Velthoven, Peter F. J.; Zahn, Andreas

2017-09-01

This study is based on fine-mode aerosol samples collected in the upper troposphere (UT) and the lowermost stratosphere (LMS) of the Northern Hemisphere extratropics during monthly intercontinental flights at 8.8-12 km altitude of the IAGOS-CARIBIC platform in the time period 1999-2014. The samples were analyzed for a large number of chemical elements using the accelerator-based methods PIXE (particle-induced X-ray emission) and PESA (particle elastic scattering analysis). Here the particulate sulfur concentrations, obtained by PIXE analysis, are investigated. In addition, the satellite-borne lidar aboard CALIPSO is used to study the stratospheric aerosol load. A steep gradient in particulate sulfur concentration extends several kilometers into the LMS, as a result of increasing dilution towards the tropopause of stratospheric, particulate sulfur-rich air. The stratospheric air is diluted with tropospheric air, forming the extratropical transition layer (ExTL). Observed concentrations are related to the distance to the dynamical tropopause. A linear regression methodology handled seasonal variation and impact from volcanism. This was used to convert each data point into stand-alone estimates of a concentration profile and column concentration of particulate sulfur in a 3 km altitude band above the tropopause. We find distinct responses to volcanic eruptions, and that this layer in the LMS has a significant contribution to the stratospheric aerosol optical depth and thus to its radiative forcing. Further, the origin of UT particulate sulfur shows strong seasonal variation. We find that tropospheric sources dominate during the fall as a result of downward transport of the Asian tropopause aerosol layer (ATAL) formed in the Asian monsoon, whereas transport down from the Junge layer is the main source of UT particulate sulfur in the first half of the year. In this latter part of the year, the stratosphere is the clearly dominating source of particulate sulfur in the UT during times of volcanic influence and under background conditions.

Nitrogen oxides in the global upper troposphere interpreted with cloud-sliced NO2 from the Ozone Monitoring Instrument

NASA Astrophysics Data System (ADS)

Marais, Eloise A.; Jacob, Daniel J.; Choi, Sungyeon; Joiner, Joanna; Belmonte-Rivas, Maria; Cohen, Ronald C.; Ryerson, Thomas B.; Weinheimer, Andrew J.; Volz-Thomas, Andreas

2017-04-01

Nitrogen oxides (NOx ≡ NO + NO2) are long lived in the upper troposphere (UT), and so have a large impact on ozone formation where ozone is a powerful greenhouse gas. Measurements of UT NOx are limited to summertime aircraft campaigns predominantly in North America. There are year-round NOx measurements from instruments onboard commercial aircraft, but NO2 measurements are susceptible to large interferences. Satellites provide global coverage, but traditional space-based NO2 observations only provide one piece of vertical information in the troposphere. New cloud-sliced satellite NO2 products offer additional vertical information by retrieving partial NO2 columns above clouds and further exploit differences in cloud heights to calculate UT NO2 mixing ratios. Two new cloud-sliced NO2 products from the Ozone Monitoring Instrument (OMI; 2004 launch) provide seasonal UT NO2 data centered at 350 hPa for 2005-2007 (NASA product) and 380 hPa for 2006 only (KNMI). Differences between the products include spectral fitting to obtain NO2 along the viewing path (slant column), the air mass factor calculation to convert slant columns to true vertical columns, treatment of the stratospheric NO2 component, and the choice of cloud products. The resultant NASA NO2 mixing ratios are 30% higher than KNMI NO2 and are consistent with summertime aircraft NO2 observations over North America. Comparison between NASA NO2 and the GEOS-Chem chemical transport model exposes glaring inadequacies in the model. In summer in the eastern US lightning NOx emissions are overestimated by at least a factor of 2, corroborated by comparison of GEOS-Chem and MOZAIC aircraft observations of reactive nitrogen (NOy). Too fast heterogeneous hydrolysis of dinitrogen pentoxide (N2O5) leads to an underestimate in UT NO2 in winter across the northern hemisphere. Absence of interannual variability in lightning flashes in the lightning NOx parameterization induces biases in UT NO2 in the tropics due to anomalous lightning activity linked to the El Niño Southern Oscillation. Ongoing work is to use GEOS-Chem to investigate the implications of updated representation of UT NOx on ozone.

Variations in periplasmic loop interactions determine the pH-dependent activity of the hexameric urea transporter UreI from Helicobacter pylori: a molecular dynamics study.

PubMed

Cáceres-Delpiano, Javier; Teneb, Jaime; Mansilla, Rodrigo; García, Apolinaria; Salas-Burgos, Alexis

2015-06-26

Helicobacter pylori is an important factor in the development of diseases such as ulcer and gastric cancer. This bacterium uses a periplasmic transporter, UreI, to deliver urea to the intracelullar space, where later it is transformed into ammonia by the cytoplasmic enzyme urease to survive the acidic condition of the human stomach. The UreI transporter presents a pH-dependent activity, where this pH-dependence remains unknown at a structural level. Althought the existance of several protonable residues in the periplasmic loops are related to the pH-dependent activity, we find interesting to have a clear view of the conformational changes involved in this phenomena through a molecular dynamic study. Molecular dynamic simulations of the UreI transporter at three different pH conditions were performed, revealing two main pH-dependent conformations, which we present as the open and close states. We find that salt bridges between the periplasmic loops are crucial interactions that stabilize these conformations. Besides, a cooperative behaviour exists between the six subunits of the system that is necessary to fulfill the activity of this transporter. We found different pH-dependent conformations of the urea transporter UreI from Helicobacter pylori, which are related to salt-bridge interactions in the periplasmic regions. The behaviour of every channel in the system is not independent, given the existance of a cooperative behaviour through the formation of salt-bridges between the subunits of the hexameric system. We believe that our results will be related to the generation of new eradication therapies using this transporter as an attractive target, denoting that the knowledge of the possible pH-dependent conformations adopted for this transporter are important for the development of rational drug design approximations.

UT/LS chemistry and transport

DOT National Transportation Integrated Search

2008-01-24

The global commercial aircraft fleet currently numbers about 10,000 and flies several billion kilometres per year while burning more than 100 MT of fuel per year at high temperatures producing mostly water and CO2. However, NOx (=NO+NO2), other minor...

Spatio-temporal aerosol particle distributions in the UT/LMS measured by the IAGOS-CARIBIC Observatory

NASA Astrophysics Data System (ADS)

Assmann, D. N.; Hermann, M.; Weigelt, A.; Martinsson, B. G.; Brenninkmeijer, C. A. M.; Rauthe-Schoech, A.; van Velthoven, P. J. F.; Boenisch, H.; Zahn, A.

2016-12-01

Submicrometer aerosol particles in the upper troposphere and lowermost stratosphere (UT/LMS) influence the Earth`s radiation budget directly and, more important, indirectly, by acting as cloud condensation nuclei and by changing trace gas concentrations through heterogeneous chemical processes. Since 1997, regular in situ UT/LMS aerosol particle measurements have been conducted by the Leibniz Institute for Tropospheric Research, Leipzig, Germany and the University of Lund, Sweden, using the the CARIBIC (now IAGOS-CARIBIC) observatory (www.caribic-atmospheric.com) onboard a passenger aircraft. Submicrometer aerosol particle number concentrations and the aerosol particle size distribution are measured using three condensation particle counters and one optical particle size spectrometer. Moreover, particle elemental composition is determined using an aerosol impactor sampler and post-flight ion beam analysis (PIXE, PESA) of the samples in the laboratory. Based on this unique data set, including meteorological analysis, we present representative spatio-temporal distributions of particle number, surface, volume, and elemental concentrations in an altitude of 8-12 km covering a large fraction of the northern hemisphere. We discuss the measured values in the different size regimes with respect to sources and sinks in different regions. Additionally, we calculated highly resolved latitudinal and longitudinal cross sections of the particle number size distribution, probability density functions and trends in particle number concentrations, but also in elemental composition, determined from our regular measurements over more than a decade. Moreover, we present the seasonality of particle number concentration in an equivelent latitude - potential temperature coordinate framework (see figure). The results are interpreted with respect to aerosol microphysics and transport using CARIBIC trace gas data like ozone and water vapour. The influence of clouds in the troposphere and the different stratosphere-troposphere-exchange processes are clearly visible. Besides providing information about UT/LMS aerosol particle sources, transport, and sinks, these distributions can be used to validate remote sensing instruments or global atmospheric aerosol models.

Spatio-temporal aerosol particle distributions in the UT/LMS measured by the IAGOS-CARIBIC Observatory

NASA Astrophysics Data System (ADS)

Assmann, Denise; Hermann, Markus; Weigelt, Andreas; Martinsson, Bengt; Brenninkmeijer, Carl; Rauthe-Schöch, Armin; van Velthoven, Peter; Bönisch, Harald; Zahn, Andreas

2017-04-01

Submicrometer aerosol particles in the upper troposphere and lowermost stratosphere (UT/LMS) influence the Earth`s radiation budget directly and, more important, indirectly, by acting as cloud condensation nuclei and by changing trace gas concentrations through heterogeneous chemical processes. Since 1997, regular in situ UT/LMS aerosol particle measurements have been conducted by the Leibniz Institute for Tropospheric Research, Leipzig, Germany and the University of Lund, Sweden, using the the CARIBIC (now IAGOS-CARIBIC) observatory (www.caribic-atmospheric.com) onboard a passenger aircraft. Submicrometer aerosol particle number concentrations and the aerosol particle size distribution are measured using three condensation particle counters and one optical particle size spectrometer. Moreover, particle elemental composition is determined using an aerosol impactor sampler and post-flight ion beam analysis (PIXE, PESA) of the samples in the laboratory. Based on this unique data set, including meteorological analysis, we present representative spatio-temporal distributions of particle number, surface, volume and elemental concentrations in an altitude of 8-12 km covering a large fraction of the northern hemisphere. We discuss the measured values in the different size regimes with respect to sources and sinks in different regions. Additionally, we calculated highly resolved latitudinal and longitudinal cross sections of the particle number size distribution, probability density functions and trends in particle number concentrations, but also in elemental composition, determined from our regular measurements over more than a decade. Moreover, we generated seasonal contour plots for particle number concentrations, the potential temperature, and the equivalent latitude. The results are interpreted with respect to aerosol microphysics and transport using CARIBIC trace gas data like ozone and water vapour. The influence of clouds in the troposphere and the different stratosphere-troposphere-exchange processes is clearly visible. Besides providing information about UT/LMS aerosol particle sources, transport, and sinks, these distributions can be used to validate remote sensing instruments or global atmospheric aerosol models.

Urea cycle disorder misdiagnosed as multiple sclerosis: a case report and review of the literature.

PubMed

Algahtani, Hussein; Alameer, Seham; Marzouk, Yousef; Shirah, Bader

2018-04-01

Urea cycle disorders are a group of inborn errors of metabolism caused by dysfunction of any of the six enzymes or two transport proteins involved in urea biosynthesis. In this paper, we report a patient who presented with neurological dysfunction and coma in the immediate postpartum period. She was misdiagnosed for many years as a case of multiple sclerosis. The importance of reporting this case is to illustrate that the wrong diagnosis of patients as being affected with multiple sclerosis for many years due to magnetic resonance imaging abnormalities rather than the classic relapsing-remitting nature of the disease may lead to catastrophic consequences. The patient was treated with intravenous steroids several times, which is contraindicated in patients with urea cycle disorders as it may precipitate acute hyperammonemic attacks. In addition, the management of urea cycle disorder could have started earlier and avoided multiple admissions to the intensive care unit. We believe that the presence of symmetric hyperintense insular cortical changes are seen in multiple hyperammonemic processes, and in the context of the clinical presentation and high ammonia levels can be suggestive of a urea cycle disorder. For any patient presenting with atypical clinical features, images should be reviewed and discussed in detail with an experienced neuroradiologist. In addition, the ammonia levels should be checked if a urea cycle disorder is suspected.

Composition and Trends of Short-Lived Trace Gases in the UT/LS over Europe Observed by the CARIBIC Aircraft

NASA Astrophysics Data System (ADS)

Baker, A. K.; Brenninkmeijer, C. A.; Oram, D. E.; O'Sullivan, D. A.; Slemr, F.; Schuck, T. J.

2009-12-01

The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from aboard a commercial airliner, and has operated since 2005 from aboard a Lufthansa Airbus 340-600 . Measurements from the container include in-situ trace gas and aerosol analyses and the collection of aerosol and whole air samples for post-flight laboratory analysis. Measurements made from the sampling flasks include greenhouse gas (GHG), halocarbon and nonmethane hydrocarbon (NMHC) analysis. CARIBIC flights originate in Frankfurt, Germany with routes to India, East Asia, South America, North America and Africa, and typical aircraft cruising altitudes of 10-12km allow for the monitoring of the upper troposphere/lower stratosphere (UT/LS) along these routes. Data collected during the aircraft’s departure from and return to Frankfurt provide a 4 year time series of near-monthly measurements of the composition of the UT/LS above Europe. Here we present a discussion of the composition of short-lived trace gases in the whole air samples collected above Europe during CARIBIC flights. Over 150 air samples were collected between May 2005 and July 2009, or about 4 samples per month. Of the whole air samples collected, about 45% showed influence by stratospheric air (i.e. very low values of GHG, NMHC and halocarbons, elevated O3, high potential vorticity). The remaining samples were representative of the upper troposphere; back trajectories for these samples indicate that a little over half were collected in air masses that had been in the boundary layer within the previous 8 days. The predominant source regions for these samples were the Gulf of Mexico and continental North America. Owing to their wide range of chemical lifetimes and the varying composition of emissions, short-lived trace gases transported to the UT/LS can be useful indicators of source region, photochemical processing and transport timescales of an air mass. Seasonal and longer-term trends in trace gases and trace gas composition are discussed, as well as composition of air masses having different origins. Additionally, we apply relationships between the different species, particularly the NMHC, to gain a qualitative understanding of photochemical processes occurring during transport from the boundary layer to the upper troposphere over Europe.

78 FR 48870 - Ocean Transportation Intermediary License Applicants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-12

...: Tufan Duygun, Manager (QI), Ozisik Serhat, Member, Application Type: Add Trade Name Daimon Logistics USA... & OFF), 3950 S 700 E, Suite 101, Salt Lake City, UT 84107, Officers: Rachel A. Kingston, Manager (QI), Elijah E. Kingston, Manager, Application Type: New NVO & OFF License. DMS America, L.L.C. (NVO & OFF...

Simulating the Fate and Transport of an Acid Mine Drainage Release

EPA Science Inventory

On August 5, 2015, approximately 3 million gallons of acid mine drainage were released from the Gold King Mine into Cement Creek in the San Juan River watershed (CO, NM, UT). The release further mobilized additional metals, which resulted in a large mass of solids and dissolved m...

Gastro-intestinal handling of water and solutes in three species of elasmobranch fish, the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate Raja eglanteria.

PubMed

Anderson, W Gary; Dasiewicz, Patricia J; Liban, Suadi; Ryan, Calen; Taylor, Josi R; Grosell, Martin; Weihrauch, Dirk

2010-04-01

The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca(2+) (19.67+/-3.65mM) and Mg(2+) (43.99+/-5.11mM) were high in L. erinacea and Mg(2+) was high (130.0+/-39.8mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO(3)(-) values were low (8.19+/-2.42 and 8.63+/-1.48mM) in both skates but very high in C. plagiosum (73.3+/-16.3mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0+/-8.1 to 0mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.

Mineral water administration may increase kidney elimination of urea, creatinine and folic acid in a concentration-dependent fashion.

PubMed

Calomino, Francesco; Di Paolo, Nicola; Nicolai, Giulia; Miglio, Antonio

2010-05-01

In a previous experimental study we showed that the administration of a large water load in a short time increases the urinary flow and the transport capacity in the excretory tract of the rabbit ureter. In human subjects drinking a water load of 25 ml/kg(BW) in 30 minutes, diuresis, creatinine and urea clearance increase more than in those drinking the same load in 24 hours. The aim of the present study was to investigate possible correlations between percent reduction and baseline values of serum urea, creatinine, folic acid, and magnesium in humans. 20 volunteers were divided in two groups. Subjects in group 1 received a water load of 25 ml/kg(BW) in 24 hours followed by the same load in 30 minutes. Subjects in group 2 received the same water load but in inverse order. Before and after each water administration, the following variables were measured and compared: diuresis, serum urea, creatinine, folic acid and magnesium concentration, and urea and creatinine clearance. Serum urea and folic acid concentration decreased up to 40% after administration of the water load in 24 hours. Serum creatinine concentration decreased up to 20% after administration of the water load in 30 minutes. The concentration drop of these metabolites increased with increasing baseline metabolite concentrations.

Effect of Phloretin on Water and Solute Movement in the Toad Bladder

PubMed Central

Levine, Sherman; Franki, Nicholas; Hays, Richard M.

1973-01-01

It is generally believed that urea crosses the cell membrane through aqueous channels, and that its movement across the membrane is accelerated in the direction of net water flow (solvent drag effect). The present report presents evidence for a vasopressin-sensitive pathway for the movement of urea, other amides, and certain non-amides, which is independent of water flow. Phloretin, when present at 10-4 M concentration in the medium bathing the luminal surface of the toad bladder, strongly inhibits the movement of urea, acetamide, and propionamide across the toad bladder, both in the absence and presence of vasopressin. The vasopressin-stimulated movement of formaldehyde and thiourea is also reduced. Osmotic water flow, on the other hand, is not affected; nor is the movement of ethanol and ethylene glycol, or the net transport of sodium. On the basis of these studies we would conclude that the movement of many, if not all, solutes across the cell membrane is independent of water flow, and that a vasopressin-sensitive carrier may be involved in the transport of certain solutes across the cell membrane. PMID:4703229

Growth, carcass yield and meat quality attributes of Red Maasai sheep fed wheat straw-based diets.

PubMed

Safari, John G; Mushi, Daniel E; Mtenga, Louis A; Kifaro, George C; Eik, Lars O

2011-01-01

Thirty-two castrated Red Maasai sheep (12.7 kg initial body weight, aged 12-18 months), were used in an 84-day experiment to evaluate diets based on treated straw upon growth performance, carcass yield and meat quality. The animals were blocked by weight into four similar groups and randomly allotted into four dietary treatments, with eight individually fed animals per treatment. The dietary treatments were ad libitum untreated wheat straw (UTS), wheat straw treated with urea and lime (TS), straw and ad libitum hay (UTSH), and TS and ad libitum hay (TSH). In addition, each experimental animal received 220 g/day (on as fed basis) of a concentrate diet. Treatment of straw increased (P < 0.05) dry matter intake (42.3 vs. 33.7 g/kg W (75)/day), energy intake (4.6 vs. 3.7 MJ ME/d) and the average daily gain (40.7 vs. 23.1 g). Animals on TS produced heavier (P < 0.05) carcasses (6.6 vs. 5.4 kg) with superior conformation than animals on UTS. Percentage cooking loss was higher in carcasses from animals fed TS compared to those from other diets. Except M. longissimus dorsi and M. semitendinosus, tenderness of muscles was not affected by diet but ageing of meat improved (P < 0.001) tenderness. Overall, straw treatment increased carcass yields with limited effects on meat quality attributes.

Reducing noise and vibration of hydraulic hybrid and plug-in hybrid electric vehicles : final report.

DOT National Transportation Integrated Search

2012-02-01

The University of Toledo University Transportation Center (UT-UTC) has identified : hybrid vehicles as one of the three areas of the research. The activities in this research : are directed towards the noise, vibration, and harshness (NVH) solutions ...

Selective inhibition of osmotic water flow by general anesthetics to toad urinary bladder.

PubMed Central

Levine, S D; Levine, R D; Worthington, R E; Hays, R M

1976-01-01

Vasopressin increases the permeability of the total urinary bladder, an analogue of the mammalian renal collecting duct, to water and small solutes, especially the amide urea. We have observed that three general anesthetic agents of clinical importance, the gases methoxyflurane and halothane and the ultrashortacting barbiturate methohexital, reversibly inhibit vasopressin-stimulated water flow, but do not depress permeability to urea, or the the lipophilic solute diphenylhydantoin. In contrast to their effects in vasopressin-treated bladders, the anesthetics do not inhibit cyclic AMP-stimulated water flow, consistent with an effect on vasopressin-responsive adenylate cyclase. The selectivity of the anesthetic-induced depression of water flow suggests that separate adenylate cyclases and cyclic AMP pools may exist for control of water and urea permeabilities in to toad bladder. Furthermore, theophylline's usual stimulatory effect on water flow, but not its effect on urea permeability, was entirely abolished in methoxyflurane-treated bladders, suggesting that separate phosphodiesterases that control water and urea permeabilities are present as well. We conclude that the majority of water and urea transport takes place via separate pathways across the rate-limiting luminal membrane of the bladder cell, and that separate vasopressin-responsive cellular pools of cyclic AMP appear to control permeability to water and to urea. PMID:184113

Nitrogen oxides and ozone in the tropopause region of the Northern Hemisphere: Measurements from commercial aircraft in 1995/1996 and 1997

NASA Astrophysics Data System (ADS)

Brunner, Dominik; Staehelin, Johannes; Jeker, Dominique; Wernli, Heini; Schumann, Ulrich

2001-11-01

Measurements of nitrogen oxides (NO and NO2) and ozone (O3) were performed from a Swissair B-747 passenger aircraft in two extended time periods (May 1995 to May 1996, August to November 1997) in the framework of the Swiss NOXAR and the European POLINAT 2 project. The measurements were obtained on a total of 623 flights between Europe and destinations in the United States and the Far East. NO2 measurements were obtained only after December 1995 and were less precise than the NO measurements. Therefore daytime NO2 values were derived from measured NO and O3 concentrations assuming photostationary equilibrium. The completed NOx data set (measured NO, measured NO2 during night, and calculated NO2 during day) includes a complete annual cycle and is the most extensive and representative data set currently available for the upper troposphere (UT) and the lower stratosphere (LS) covering a significant proportion of the northern hemisphere between 15°N and 65°N. NOx concentrations in midlatitudes (30°-60°N) showed a marked seasonal variation both in the UT and the LS with a maximum in summer (median/mean values of 159/264 pptv in UT, 199/237 pptv in LS) and a minimum in winter (51/99 pptv in UT, 67/91 pptv in LS). Mean NOx concentrations were generally much higher than the respective median values, in particular in the UT, which reflects the important contribution from comparatively few very high concentrations observed in large-scale convection/lightning and small-scale aircraft plumes. Seasonal mean NOx concentrations in the UT were up to 3-4 times higher over continental regions than over the North Atlantic during summer. Lightning production of NO and convective vertical transport from the polluted boundary layer thus appear to have dominated the upper tropospheric NOx budget over these continental regions, particularly during summer. Ozone concentrations at aircraft cruising levels typically varied by an order of magnitude due to the strong vertical gradient in the LS. Seasonal mean values were dominated by large-scale dynamical processes controlling the altitude of the tropopause and the O3 abundance in the LS. O3 in the UT in midlatitudes showed a broad maximum between June and August, typical of observations in the free troposphere.

Flapping current sheet with superposed waves seen in space and on the ground

NASA Astrophysics Data System (ADS)

Wang, G. Q.; Volwerk, M.; Nakamura, R.; Boakes, P.; Zhang, T. L.; Yoshikawa, A.; Baishev, D. G.

2014-12-01

A wavy current sheet event observed on 15 October 2004 between 1235 and 1300 UT has been studied by using Cluster and ground-based magnetometer data. Waves propagating from the tail center to the duskside flank with a period ~30 s and wavelength ~1 RE are superimposed on a flapping current sheet, accompanied with a bursty bulk flow. Three Pi2 pulsations, with onset at ~1236, ~1251, and ~1255 UT, respectively, are observed at the Tixie station located near the foot points of Cluster. The mechanism creating the Pi2 (period ~40 s) onset at ~1236 UT is unclear. The second Pi2 (period ~90 s, onset at ~1251 UT) is associated with a strong field-aligned current, which has a strong transverse component of the magnetic field, observed by Cluster with a time delay ~60 s. We suggest that it is caused by bouncing Alfvén waves between the northern and southern ionosphere which transport the field-aligned current. For the third Pi2 (period ~60 s) there is almost no damping at the first three periods. They occur in conjunction with periodic field-aligned currents one-on-one with 72 s delay. We suggest that it is generated by these periodic field-aligned currents. We conclude that the strong field-aligned currents generated in the plasma sheet during flapping with superimposed higher-frequency waves can drive Pi2 pulsations on the ground, and periodic field-aligned currents can even control the period of the Pi2s.

Atmospheric inorganic trace contaminants in Finland, especially in the Gulf of Finland area

NASA Astrophysics Data System (ADS)

Jalkanen, Liisa Maria

Atmospheric aerosol samples were collected at Utö and Virolahti in the Gulf of Finland area and Ähtäri in Central Finland using a filter pack. The samples were analysed by instrumental neutron activation analysis (INAA) and inductively coupled plasma mass-spectrometry (ICP-MS) for 34 elements including halogens and heavy metals. A very simple and quantitative acid digestion method was developed for the dissolution of the aerosol samples for ICP-MS analysis. Analysis of the elemental data is given using trajectories, principal component analysis and long-range transport modelling. The average total (fine + coarse) atmospheric concentrations range at Utö from 0.083 ng m -3 for Cd to 730 ng m-3 for Na. The sea areas (Utö, Virolahti, Hailuoto) have most of the heavy metal air pollution in Finland, as witnessed by the aerosol concentration and wet deposition data. There is a clear decreasing gradient in the deposition of As, Cd, Cr, Pb, and V from South to North in Finland. In general, the trace element concentrations and deposition are lower in Finland than in Central Europe. The effect of large particulate emission sources in Estonia can be seen in the elemental concentrations of atmospheric particles and in the deposition around the eastern Gulf of Finland region. There has been a remarkable decrease in heavy metal emissions in Finland during the 1990s. However, due to long-range transport, the decrease in deposition as witnessed by analysis of these concentrations in precipitation and moss is much less than would be expected.

Reducing noise and vibration of hydraulic hybrid and plug-in hybrid electric vehicles : phase II final report.

DOT National Transportation Integrated Search

2010-03-01

The University of Toledo University Transportation Center (UT-UTC) has identified hybrid vehicles as one of the three areas of the research. The activities proposed in this research proposal are directed towards the noise, vibration, and harshness (N...

Reducing noise and vibration of hydraulic hybrid and plug-in hybrid electric vehicles : phase III final report.

DOT National Transportation Integrated Search

2011-08-01

The University of Toledo University Transportation Center (UT-UTC) has identified hybrid vehicles as one of the three areas of the research. The activities proposed in this research proposal are directed towards the noise, vibration, and harshness (N...

Constitutive expression of the DUR1,2 gene in an industrial yeast strain to minimize ethyl carbamate production during Chinese rice wine fermentation.

PubMed

Wu, Dianhui; Li, Xiaomin; Lu, Jian; Chen, Jian; Zhang, Liang; Xie, Guangfa

2016-01-01

Urea and ethanol are the main precursors of ethyl carbamate (EC) in Chinese rice wine. During fermentation, urea is generated from arginine by arginase in Saccharomyces cerevisiae, and subsequently cleaved by urea amidolyase or directly transported out of the cell into the fermentation liquor, where it reacts with ethanol to form EC. To reduce the amount of EC in Chinese rice wine, we metabolically engineered two yeast strains, N85(DUR1,2) and N85(DUR1,2)-c, from the wild-type Chinese rice wine yeast strain N85. Both new strains were capable of constitutively expressing DUR1,2 (encodes urea amidolyase) and thus enhancing urea degradation. The use of N85(DUR1,2) and N85(DUR1,2)-c reduced the concentration of EC in Chinese rice wine fermented on a small-scale by 49.1% and 55.3%, respectively, relative to fermentation with the parental strain. All of the engineered strains showed good genetic stability and minimized the production of urea during fermentation, with no exogenous genes introduced during genetic manipulation, and were therefore suitable for commercialization to increase the safety of Chinese rice wine. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Urea recycling contributes to nitrogen retention in calves fed milk replacer and low-protein solid feed.

PubMed

Berends, Harma; van den Borne, Joost J G C; Røjen, Betina A; van Baal, Jürgen; Gerrits, Walter J J

2014-07-01

Urea recycling, with urea originating from catabolism of amino acids and hepatic detoxification of ammonia, is particularly relevant for ruminant animals, in which microbial protein contributes substantially to the metabolizable protein supply. However, the quantitative contribution of urea recycling to protein anabolism in calves during the transition from preruminants (milk-fed calves) to ruminants [solid feed (SF)-fed calves] is unknown. The aim of this study was to quantify urea recycling in milk-fed calves when provided with low-protein SF. Forty-eight calves [164 ± 1.6 kg body weight (BW)] were assigned to 1 of 4 SF levels [0, 9, 18, and 27 g of dry matter (DM) SF · kg BW(-0.75) · d⁻¹] provided in addition to an identical amount of milk replacer. Urea recycling was quantified after a 24-h intravenous infusion of [¹⁵N₂]urea by analyzing urea isotopomers in 68-h fecal and urinary collections. Real-time qPCR was used to measure gene expression levels of bovine urea transporter B (bUTB) and aquaglyceroporin-3 and aquaglyceroporin-7 in rumen wall tissues. For every incremental gram of DM SF intake (g DM · kg(0.75)), nitrogen intake increased by 0.70 g, and nitrogen retention increased by 0.55 g (P < 0.01). Of this increase in nitrogen retention, 19% could be directly explained by urea recycling. Additionally, part of the observed increase in nitrogen retention could be explained by the extra protein provided by the SF and likely by a greater efficiency of postabsorptive use of nitrogen for gain. Ruminal bUTB abundance increased (P < 0.01) with SF provision. Aquaglyceroporin-3 expression increased (P < 0.01) with SF intake, but aquaglyceroporin-7 expression did not. We conclude that in addition to the increase in digested nitrogen, urea recycling contributes to the observed increase in nitrogen retention with increasing SF intake in milk-fed calves. Furthermore, ruminal bUTB and aquaglyceroporin-3 expression are upregulated with SF intake, which might be associated with urea recycling. © 2014 American Society for Nutrition.

Brain urea increase is an early Huntington's disease pathogenic event observed in a prodromal transgenic sheep model and HD cases.

PubMed

Handley, Renee R; Reid, Suzanne J; Brauning, Rudiger; Maclean, Paul; Mears, Emily R; Fourie, Imche; Patassini, Stefano; Cooper, Garth J S; Rudiger, Skye R; McLaughlan, Clive J; Verma, Paul J; Gusella, James F; MacDonald, Marcy E; Waldvogel, Henry J; Bawden, C Simon; Faull, Richard L M; Snell, Russell G

2017-12-26

The neurodegenerative disorder Huntington's disease (HD) is typically characterized by extensive loss of striatal neurons and the midlife onset of debilitating and progressive chorea, dementia, and psychological disturbance. HD is caused by a CAG repeat expansion in the Huntingtin ( HTT ) gene, translating to an elongated glutamine tract in the huntingtin protein. The pathogenic mechanism resulting in cell dysfunction and death beyond the causative mutation is not well defined. To further delineate the early molecular events in HD, we performed RNA-sequencing (RNA-seq) on striatal tissue from a cohort of 5-y-old OVT73 -line sheep expressing a human CAG-expansion HTT cDNA transgene. Our HD OVT73 sheep are a prodromal model and exhibit minimal pathology and no detectable neuronal loss. We identified significantly increased levels of the urea transporter SLC14A1 in the OVT73 striatum, along with other important osmotic regulators. Further investigation revealed elevated levels of the metabolite urea in the OVT73 striatum and cerebellum, consistent with our recently published observation of increased urea in postmortem human brain from HD cases. Extending that finding, we demonstrate that postmortem human brain urea levels are elevated in a larger cohort of HD cases, including those with low-level neuropathology (Vonsattel grade 0/1). This elevation indicates increased protein catabolism, possibly as an alternate energy source given the generalized metabolic defect in HD. Increased urea and ammonia levels due to dysregulation of the urea cycle are known to cause neurologic impairment. Taken together, our findings indicate that aberrant urea metabolism could be the primary biochemical disruption initiating neuropathogenesis in HD.

Manure effects on soil N in eroded and non-eroded, sprinkler-irrigated soil

USDA-ARS?s Scientific Manuscript database

Manure effects on nitrate-N transport through irrigated, low-organic matter calcareous soil are not well known. This field study quantified the effects of a one-time fall application of stockpiled dairy manure and urea on in-season and over-winter nitrate-N transport through non-eroded and eroded (...

13. Photographic copy of photocopy of bridge drawing, plans and ...

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

13. Photographic copy of photocopy of bridge drawing, plans and elevations (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 5 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

14. Photographic copy of photocopy of bridge drawing, reinforced rod ...

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

14. Photographic copy of photocopy of bridge drawing, reinforced rod specifications (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 6 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

40. CONSTRUCTION OF GALLERY NO. 3, SHOWING INCLINED PLANE USED ...

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

40. CONSTRUCTION OF GALLERY NO. 3, SHOWING INCLINED PLANE USED TO TRANSPORT MATERIALS, ALSO SPOIL FROM TUNNEL INTERIOR. POWDER HOUSE AND TOOL SHED VISIBLE TO RIGHT OF BASE INCLINE - Zion-Mount Carmel Highway, Tunnel, Two miles east of Zion Canyon Scenic Drive, Springdale, Washington County, UT

8. VIEW OF STEEL, STOCKDRAWN EARTH SCRAPER USED TO SCAPE ...

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

8. VIEW OF STEEL, STOCK-DRAWN EARTH SCRAPER USED TO SCAPE EARTH BORROW MATERIAL AND TRANSPORT IT TO DAM DURING CONSTRUCTION, LOOKING SOUTH - High Mountain Dams in Upalco Unit, Five Point Lake Dam, Ashley National Forest, 12 miles Northwest of Swift Creek Campground, Mountain Home, Duchesne County, UT

Reducing noise and vibration of hydraulic hybrid and plug-in hybrid electric vehicles : phase II, final report, March 2010.

DOT National Transportation Integrated Search

2010-03-01

The University of Toledo University Transportation Center (UT-UTC) has identified hybrid vehicles as one of the three areas of the research. The activities proposed in this research proposal are directed towards the noise, vibration, and harshness (N...

Reducing noise and vibration of hydraulic hybrid and plug-in hybrid electric vehicles : phase I final report, March 2009.

DOT National Transportation Integrated Search

2009-03-01

The University of Toledo University Transportation Center (UT-UTC) has identified hybrid vehicles as one of the three areas of the research. The activities proposed in this research proposal are directed towards the noise, vibration, and harshness (N...

Profile of sodium phenylbutyrate granules for the treatment of urea-cycle disorders: patient perspectives.

PubMed

Peña-Quintana, Luis; Llarena, Marta; Reyes-Suárez, Desiderio; Aldámiz-Echevarria, Luis

2017-01-01

Urea-cycle disorders are a group of rare hereditary metabolic diseases characterized by deficiencies of one of the enzymes and transporters involved in the urea cycle, which is necessary for the removal of nitrogen produced from protein breakdown. These hereditary metabolic diseases are characterized by hyperammonemia and life-threatening hyperammonemic crises. Pharmacological treatment of urea-cycle disorders involves alternative nitrogen-scavenging pathways. Sodium benzoate combines with glycine and phenylacetate/phenylbutyrate with glutamine, forming, respectively, hippuric acid and phenylacetylglutamine, which are eliminated in the urine. Among the ammonia-scavenging drugs, sodium phenylbutyrate is a well-known long-term treatment of urea-cycle disorders. It has been used since 1987 as an investigational new drug, and was approved for marketing in the US in 1996 and the EU in 1999. However, sodium phenylbutyrate has an aversive odor and taste, which may compromise patients' compliance, and many patients have reported difficulty in taking this drug. Sodium phenylbutyrate granules are a new tasteless and odor-free formulation of sodium phenylbutyrate, which is indicated in the treatment of urea-cycle disorders. This recently developed taste-masked formulation of sodium phenylbutyrate granules was designed to overcome the considerable issues that taste has on adherence to therapy. Several studies have reported the clinical experience of patients with urea-cycle disorders treated with this new tasteless formulation of sodium phenylbutyrate. Analysis of the data indicated that this taste-masked formulation of sodium phenylbutyrate granules improved quality of life for urea-cycle disorder patients. Furthermore, a postmarketing report on the use of the product has confirmed the previous observations of improved compliance, efficacy, and safety with this taste-masked formulation of sodium phenylbutyrate.

Profile of sodium phenylbutyrate granules for the treatment of urea-cycle disorders: patient perspectives

PubMed Central

Peña-Quintana, Luis; Llarena, Marta; Reyes-Suárez, Desiderio; Aldámiz-Echevarria, Luis

2017-01-01

Urea-cycle disorders are a group of rare hereditary metabolic diseases characterized by deficiencies of one of the enzymes and transporters involved in the urea cycle, which is necessary for the removal of nitrogen produced from protein breakdown. These hereditary metabolic diseases are characterized by hyperammonemia and life-threatening hyperammonemic crises. Pharmacological treatment of urea-cycle disorders involves alternative nitrogen-scavenging pathways. Sodium benzoate combines with glycine and phenylacetate/phenylbutyrate with glutamine, forming, respectively, hippuric acid and phenylacetylglutamine, which are eliminated in the urine. Among the ammonia-scavenging drugs, sodium phenylbutyrate is a well-known long-term treatment of urea-cycle disorders. It has been used since 1987 as an investigational new drug, and was approved for marketing in the US in 1996 and the EU in 1999. However, sodium phenylbutyrate has an aversive odor and taste, which may compromise patients’ compliance, and many patients have reported difficulty in taking this drug. Sodium phenylbutyrate granules are a new tasteless and odor-free formulation of sodium phenylbutyrate, which is indicated in the treatment of urea-cycle disorders. This recently developed taste-masked formulation of sodium phenylbutyrate granules was designed to overcome the considerable issues that taste has on adherence to therapy. Several studies have reported the clinical experience of patients with urea-cycle disorders treated with this new tasteless formulation of sodium phenylbutyrate. Analysis of the data indicated that this taste-masked formulation of sodium phenylbutyrate granules improved quality of life for urea-cycle disorder patients. Furthermore, a postmarketing report on the use of the product has confirmed the previous observations of improved compliance, efficacy, and safety with this taste-masked formulation of sodium phenylbutyrate. PMID:28919721

Nitrogen metabolism of the intestine during digestion in a teleost fish, the plainfin midshipman (Porichthys notatus).

PubMed

Bucking, Carol; LeMoine, Christophe M R; Craig, Paul M; Walsh, Patrick J

2013-08-01

Digestion affects nitrogen metabolism in fish, as both exogenous and endogenous proteins and amino acids are catabolized, liberating ammonia in the process. Here we present a model of local detoxification of ammonia by the intestinal tissue of the plainfin midshipman (Porichthys notatus) during digestion, resulting in an increase in urea excretion of gastrointestinal origin. Corroborating evidence indicated whole-animal ammonia and urea excretion increased following feeding, and ammonia levels within the lumen of the midshipman intestine increased to high levels (1.8±0.4 μmol N g(-1)). We propose that this ammonia entered the enterocytes and was detoxified to urea via the ornithine-urea cycle (O-UC) enzymes, as evidenced by a 1.5- to 2.9-fold post-prandial increase in glutamine synthetase activity (0.14±0.05 and 0.28±0.02 μmol min(-1) g(-1) versus 0.41±0.03 μmol min(-1) g(-1)) and an 8.7-fold increase in carbamoyl phosphate synthetase III activity (0.3±1.2 versus 2.6±0.4 nmol min(-1) g(-1)). Furthermore, digestion increased urea production by isolated gastrointestinal tissue 1.7-fold, supporting our hypothesis that intestinal tissue synthesizes urea in response to feeding. We further propose that the intestinal urea may have been excreted into the intestinal lumen via an apical urea transporter as visualized using immunohistochemistry. A portion of the urea was then excreted to the environment along with the feces, resulting in the observed increase in urea excretion, while another portion may have been used by intestinal ureolytic bacteria. Overall, we propose that P. notatus produces urea within the enterocytes via a functional O-UC, which is then excreted into the intestinal lumen. Our model of intestinal nitrogen metabolism does not appear to be universal as we were unab le to activate the O-UC in the intestine of fed rainbow trout. However, literature values suggest that multiple fish species could follow this model.

Genetic variation in the urea cycle: a model resource for investigating key candidate genes for common diseases.

PubMed

Mitchell, Sabrina; Ellingson, Clint; Coyne, Thomas; Hall, Lynn; Neill, Meaghan; Christian, Natalie; Higham, Catherine; Dobrowolski, Steven F; Tuchman, Mendel; Summar, Marshall

2009-01-01

The urea cycle is the primary means of nitrogen metabolism in humans and other ureotelic organisms. There are five key enzymes in the urea cycle: carbamoyl-phosphate synthetase 1 (CPS1), ornithine transcarbamylase (OTC), argininosuccinate synthetase (ASS1), argininosuccinate lyase (ASL), and arginase 1 (ARG1). Additionally, a sixth enzyme, N-acetylglutamate synthase (NAGS), is critical for urea cycle function, providing CPS1 with its necessary cofactor. Deficiencies in any of these enzymes result in elevated blood ammonia concentrations, which can have detrimental effects, including central nervous system dysfunction, brain damage, coma, and death. Functional variants, which confer susceptibility for disease or dysfunction, have been described for enzymes within the cycle; however, a comprehensive screen of all the urea cycle enzymes has not been performed. We examined the exons and intron/exon boundaries of the five key urea cycle enzymes, NAGS, and two solute carrier transporter genes (SLC25A13 and SLC25A15) for sequence alterations using single-stranded conformational polymorphism (SSCP) analysis and high-resolution melt profiling. SSCP was performed on a set of DNA from 47 unrelated North American individuals with a mixture of ethnic backgrounds. High-resolution melt profiling was performed on a nonoverlapping DNA set of either 47 or 100 unrelated individuals with a mixture of backgrounds. We identified 33 unarchived polymorphisms in this screen that potentially play a role in the variation observed in urea cycle function. Screening all the genes in the pathway provides a catalog of variants that can be used in investigating candidate diseases. Copyright 2008 Wiley-Liss, Inc.

Membrane rejection of nitrogen compounds

NASA Technical Reports Server (NTRS)

Lee, S.; Lueptow, R. M.

2001-01-01

Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

Trimodal distribution of ozone and water vapor in the UT/LS during boreal summer

NASA Astrophysics Data System (ADS)

Dunkerton, T. J.

2004-12-01

The relation of ozone and water vapor in the upper troposphere and lower stratosphere (UT/LS) is strongly influenced by the off-equatorial Asian and North American monsoons in boreal summer. Both regions experience hydration, presumably as a result of deep convection. This behavior contrasts sharply with the apparent dehydrating influence of near-equatorial deep convection in boreal winter. There is also a striking difference in ozone between Asia and North America in boreal summer. Over Asia, ozone concentrations are low, evidently a result of ubiquitous deep convection and the vertical transport of ozone-poor air, while over North America, ozone concentrations are much higher. Since deep convection also occurs in the North American monsoon, it appears that the difference in ozone concentration between Asia and North America in boreal summer reflects a differing influence of the large-scale circulation in the two regions: specifically, (i) isolation of the Tibetan anticyclone versus (ii) the intrusion of filaments of ozone-rich air from the stratosphere over North America. During boreal summer, as in winter, near-equatorial concentrations of ozone and water vapor are low near the equator. The result of these geographical variations is a trimodal distribution of ozone and water-vapor correlation. Our talk reviews the observational evidence of this trimodal distribution and possible dynamical and microphysical causes, focusing primarily on the quality and possible sampling bias of satellite and aircraft measurements. A key issue is the ability of HALOE to sample areas of ubiquitous deep convection. Other issues include the vertical structure of tracer anomalies, isentropic stirring in the UT/LS, horizontal transport of biomass burning products lofted by deep convection, and connections to the moist phase of the tropical `tape recorder' signal in water vapor.

Trimodal distribution of ozone and water vapor in the UT/LS during boreal summer

NASA Astrophysics Data System (ADS)

Dunkerton, T. J.

2004-05-01

The relation of ozone and water vapor in the upper troposphere and lower stratosphere (UT/LS) is strongly influenced by the off-equatorial Asian and North American monsoons in boreal summer. Both regions experience hydration, presumably as a result of deep convection. This behavior contrasts sharply with the apparent dehydrating influence of near-equatorial deep convection in boreal winter. There is also a striking difference in ozone between Asia and North America in boreal summer. Over Asia, ozone concentrations are low, evidently a result of ubiquitous deep convection and the vertical transport of ozone-poor air, while over North America, ozone concentrations are much higher. Since deep convection also occurs in the North American monsoon, it appears that the difference in ozone concentration between Asia and North America in boreal summer reflects a differing influence of the large-scale circulation in the two regions: specifically, (i) isolation of the Tibetan anticyclone versus (ii) the intrusion of filaments of ozone-rich air from the stratosphere over North America. During boreal summer, as in winter, near-equatorial concentrations of ozone and water vapor are low near the equator. The result of these geographical variations is a trimodal distribution of ozone and water-vapor correlation. Our talk reviews the observational evidence of this trimodal distribution and possible dynamical and microphysical causes, focusing primarily on the quality and possible sampling bias of satellite and aircraft measurements. A key issue is the ability of HALOE to sample areas of ubiquitous deep convection. Other issues include the vertical structure of tracer anomalies, isentropic stirring in the UT/LS, horizontal transport of biomass burning products lofted by deep convection, and connections to the moist phase of the tropical `tape recorder' signal in water vapor.

Flapping current sheet with superposed waves seen in space and on the ground

NASA Astrophysics Data System (ADS)

Wang, Guoqiang; Volwerk, Martin; Nakamura, Rumi; Boakes, Peter; Zhang, Tielong; Ge, Yasong; Yoshikawa, Akimasa; Baishev, Dmitry

2015-04-01

A wavy current sheet event observed on 15th of October 2004 between 1235 and 1300 UT has been studied by using Cluster and ground-based magnetometer data. Waves propagating from the tail centre to the duskside flank with a period ~30 s and wavelength ~1 RE, are superimposed on a flapping current sheet, accompanied with a bursty bulk flow (BBF). Three Pi2 pulsations, with onset at ~1236, ~1251 and ~1255 UT, respectively, are observed at the Tixie (TIK) station located near the foot-points of Cluster. The mechanism creating the Pi2 (period ~40 s) onset at ~1236 UT is unclear. The second Pi2 (period ~90 s, onset at ~1251 UT) is associated with a strong field-aligned current, which has a strong transverse component of the magnetic field, observed by Cluster with a time delay ~60 s. We suggest that it is caused by bouncing Alfvén waves between the northern and southern ionosphere which transport the field-aligned current. For the third Pi2 (period ~60 s) there is almost no damping at the first three periods. They occur in conjunction with periodic field-aligned currents one-on-one with 72s delay. We suggest that it is generated by these periodic field-aligned currents. We conclude that the strong field-aligned currents generated in the plasma sheet during flapping with superimposed higher frequency waves can drive Pi2 pulsations on the ground, and periodic field-aligned currents can even control the period of the Pi2s.

Distributions of imidacloprid, imidacloprid-olefin and imidacloprid-urea in green plant tissues and roots of rapeseed (Brassica napus) from artificially contaminated potting soil.

PubMed

Seifrtova, Marcela; Halesova, Tatana; Sulcova, Klara; Riddellova, Katerina; Erban, Tomas

2017-05-01

Imidacloprid-urea is the primary imidacloprid soil metabolite, whereas imidacloprid-olefin is the main plant-relevant metabolite and is more toxic to insects than imidacloprid. We artificially contaminated potting soil and used quantitative UHPLC-QqQ-MS/MS to determine the imidacloprid, imidacloprid-olefin and imidacloprid-urea distributions in rapeseed green plant tissues and roots after 4 weeks of exposure. In soil, the imidacloprid/imidacloprid-urea molar ratios decreased similarly after the 250 and 2500 µg kg -1 imidacloprid treatments. The imidacloprid/imidacloprid-urea molar ratios in the root and soil were similar, whereas in the green plant tissue, imidacloprid-urea increased more than twofold compared with the root. Although imidacloprid-olefin was prevalent in the green plant tissues, with imidacloprid/imidacloprid-olefin molar ratios of 2.24 and 1.47 for the 250 and 2500 µg kg -1 treatments respectively, it was not detected in the root. However, imidacloprid-olefin was detected in the soil after the 2500 µg kg -1 imidacloprid treatment. Significant proportions of imidacloprid-olefin and imidacloprid-urea in green plant tissues were demonstrated. The greater imidacloprid supply increased the imidacloprid-olefin/imidacloprid molar ratio in the green plant tissues. The absence of imidacloprid-olefin in the root excluded its retransport from leaves. The similar imidacloprid/imidacloprid-urea ratios in the soil and root indicated that the root serves primarily for transporting these substances. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Effects of supplemental energy and protein on forage digestion and urea kinetics in growing beef cattle.

PubMed

Bailey, E A; Titgemeyer, E C; Olson, K C; Brake, D W; Jones, M L; Anderson, D E

2012-10-01

Effects of supplemental energy sources on nutrient digestion and urea kinetics at 2 levels of degradable intake protein were evaluated in cattle (Bos taurus). Six ruminally and duodenally cannulated steers (208 ± 17 kg) were used in a 6 × 6 Latin square with treatments arranged as a 3 × 2 factorial. Energy treatments included a control, 600 g glucose dosed ruminally once daily, and 480 g VFA infused ruminally over 8 h daily. Casein (120 or 240 g) was dosed ruminally once daily. Steers had ad libitum access to prairie hay (5.8% CP). Jugular infusion of (15)N(15)N-urea with measurement of enrichment in urine was used to measure urea kinetics. Infusing VFA decreased (P < 0.01) forage intake by 27%. Supplementing glucose decreased (P < 0.01) total tract NDF digestibility and tended to decrease ruminal NDF digestibility; depressions in response to glucose tended to be greater at the lower level of casein. Increasing casein decreased (P < 0.02) ruminal pH. Infusing VFA decreased pH only during infusions, whereas glucose decreased pH 2 h after dosing. Ruminal concentrations of NH(3), acetate, and propionate decreased and butyrate concentration increased when glucose was supplemented. Increasing casein supplementation increased (P < 0.01) ruminal concentrations of NH(3), acetate, and propionate. Supplemental energy decreased (P = 0.03) plasma urea-N concentration, but casein level did not affect it (P = 0.16). Microbial N flow was greater (P < 0.04) for 240 than for 120 g/d casein but was not affected by supplemental energy (P = 0.23). Urea-N entry rate and gut entry of urea-N were not affected (P ≥ 0.12) by supplemental energy or casein, but the proportion of urea production that was recycled to the gut was less (P = 0.01) when 240 g/d rather than 120 g/d casein was provided. Compared with VFA, glucose tended (P = 0.07) to increase the proportion of urea-N entry rate that was recycled to the gut. Supplementation with glucose led to more (P = 0.01) microbial uptake of recycled urea than did supplementation with VFA. Urea recycling did not differ greatly among treatments despite impacts on ruminal pH and NH(3) and on plasma urea-N that were expected to alter urea transport across ruminal epithelium. Lack of treatment effects on urea production indicate that the complete diets did not provide excessive amounts of N and that increases of intestinally available AA were used efficiently by cattle for protein deposition.

Transcellular movement of hydroxyurea is mediated by specific solute carrier transporters

PubMed Central

Walker, Aisha L.; Franke, Ryan M.; Sparreboom, Alex; Ware, Russell E.

2015-01-01

Objective Hydroxyurea has proven laboratory and clinical therapeutic benefits for sickle cell anemia (SCA) and other diseases, yet many questions remain regarding its in vivo pharmacokinetic and pharmacodynamic profiles. Previous reports suggest that hydroxyurea passively diffuses across cells, but its observed rapid absorption and distribution are more consistent with facilitated or active transport. We investigated the potential role of solute carrier (SLC) transporters in cellular uptake and accumulation of hydroxyurea. Materials and Methods Passive diffusion of hydroxyurea across cell membranes was determined using the parallel artificial membrane permeability assay. SLC transporter screens were conducted using in vitro intracellular drug accumulation and transcellular transport assays in cell lines and oocytes overexpressing SLC transporters. Gene expression of SLC transporters was measured by real-time PCR in human tissues and cell lines. Results Hydroxyurea had minimal diffusion across a lipid bilayer but was a substrate for 5 different SLC transporters belonging to the OCTN and OATP families of transporters and urea transporters A and B. Further characterization of hydroxyurea transport revealed that cellular uptake by OATP1B3 is time and temperature dependent and inhibited by known substrates of OATP1B3. Urea transporters A and B are expressed differentially in human tissues and erythroid cells, and transport hydroxyurea bidirectionally via facilitated diffusion. Conclusions These studies provide new insight into drug transport proteins that may be involved in the in vivo absorption, cellular distribution, and elimination of hydroxyurea. Elucidation of hydroxyurea transcellular movement should improve our understanding of its pharmacokinetics and pharmacodynamics, and may help explain some of the inter-patient drug variability observed in patients with SCA. PMID:21256917

10. Photographic copy of photocopy of bridge drawing, half plans ...

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

10. Photographic copy of photocopy of bridge drawing, half plans and elevation (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 2 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

11. Photographic copy of photocopy of bridge drawing, half plans ...

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

11. Photographic copy of photocopy of bridge drawing, half plans and footings (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 3 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

12. Photographic copy of photocopy of bridge drawing, half plans ...

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

12. Photographic copy of photocopy of bridge drawing, half plans and abutment elevation (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 4 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

9. Photographic copy of photocopy of bridge drawing, situation plan ...

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

9. Photographic copy of photocopy of bridge drawing, situation plan and profile on center line (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 1 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

Functional expression of a heterologous nickel-dependent, ATP-independent urease in Saccharomyces cerevisiae.

PubMed

Milne, N; Luttik, M A H; Cueto Rojas, H F; Wahl, A; van Maris, A J A; Pronk, J T; Daran, J M

2015-07-01

In microbial processes for production of proteins, biomass and nitrogen-containing commodity chemicals, ATP requirements for nitrogen assimilation affect product yields on the energy producing substrate. In Saccharomyces cerevisiae, a current host for heterologous protein production and potential platform for production of nitrogen-containing chemicals, uptake and assimilation of ammonium requires 1 ATP per incorporated NH3. Urea assimilation by this yeast is more energy efficient but still requires 0.5 ATP per NH3 produced. To decrease ATP costs for nitrogen assimilation, the S. cerevisiae gene encoding ATP-dependent urease (DUR1,2) was replaced by a Schizosaccharomyces pombe gene encoding ATP-independent urease (ure2), along with its accessory genes ureD, ureF and ureG. Since S. pombe ure2 is a Ni(2+)-dependent enzyme and Saccharomyces cerevisiae does not express native Ni(2+)-dependent enzymes, the S. pombe high-affinity nickel-transporter gene (nic1) was also expressed. Expression of the S. pombe genes into dur1,2Δ S. cerevisiae yielded an in vitro ATP-independent urease activity of 0.44±0.01 µmol min(-1) mg protein(-1) and restored growth on urea as sole nitrogen source. Functional expression of the Nic1 transporter was essential for growth on urea at low Ni(2+) concentrations. The maximum specific growth rates of the engineered strain on urea and ammonium were lower than those of a DUR1,2 reference strain. In glucose-limited chemostat cultures with urea as nitrogen source, the engineered strain exhibited an increased release of ammonia and reduced nitrogen content of the biomass. Our results indicate a new strategy for improving yeast-based production of nitrogen-containing chemicals and demonstrate that Ni(2+)-dependent enzymes can be functionally expressed in S. cerevisiae. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Transport of microplastics by two collembolan species.

PubMed

Maaß, Stefanie; Daphi, Daniel; Lehmann, Anika; Rillig, Matthias C

2017-06-01

Plastics, despite their great benefits, have become a ubiquitous environmental pollutant, with microplastic particles having come into focus most recently. Microplastic effects have been intensely studied in aquatic, especially marine systems; however, there is lack of studies focusing on effects on soil and its biota. A basic question is if and how surface-deposited microplastic particles are transported into the soil. We here wished to test if soil microarthropods, using Collembola, can transport these particles over distances of centimeters within days in a highly controlled experimental set-up. We conducted a fully factorial experiment with two collembolan species of differing body size, Folsomia candida and Proisotoma minuta, in combination with urea-formaldehyde particles of two different particle sizes. We observed significant differences between the species concerning the distance the particles were transported. F. candida was able to transport larger particles further and faster than P. minuta. Using video, we observed F. candida interacting with urea-formaldehyde particles and polyethylene terephthalate fibers, showing translocation of both material types. Our data clearly show that microplastic particles can be moved and distributed by soil microarthropods. Although we did not observe feeding, it is possible that microarthropods contribute to the accumulation of microplastics in the soil food web. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advances in urea cycle neuroimaging: Proceedings from the 4th International Symposium on urea cycle disorders, Barcelona, Spain, September 2013.

PubMed

Pacheco-Colón, Ileana; Fricke, Stanley; VanMeter, John; Gropman, Andrea L

2014-01-01

Our previous imaging research performed as part of a Urea Cycle Rare Disorders Consortium (UCRDC) grant, has identified specific biomarkers of neurologic injury in ornithine transcarbamylase deficiency, OTCD. While characterization of mutations can be achieved in most cases, this information does not necessarily predict the severity of the underlying neurological syndrome. The biochemical consequences of any mutation may be modified additionally by a large number of factors, including contributions of other enzymes and transport systems that mediate flux through the urea cycle, diet and other environmental factors. These factors likely vary from one patient to another, and they give rise to heterogeneity of clinical severity. Affected cognitive domains include non-verbal learning, fine motor processing, reaction time, visual memory, attention, and executive function. Deficits in these capacities may be seen in symptomatic patients, as well as asymptomatic carriers with normal IQ and correlate with variances in brain structure and function in these patients. Using neuroimaging we can identify biomarkers that reflect the downstream impact of UCDs on cognition. This manuscript is a summary of the presentation from the 4th International Consortium on urea cycle disorders held in, Barcelona, Spain, September 2, 2014. Copyright © 2014 Elsevier Inc. All rights reserved.

Aluminum and temperature alteration of cell membrane permeability of Quercus rubra

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

Junping Chen; Sucoff, E.I.; Stadelmann, E.J.

1991-06-01

Al toxicity is the major factor limiting plant growth in acid soils. This report extends research on Al-induced changes in membrane behavior of intact root cortex cells of Northern red oak (Quercus rubra). Membrane permeability was determined by the plasmometric method for individual intact cells at temperatures from 2 or 4 to 35 C. Al (0.37 millimolar) significantly increased membrane permeability to urea and monoethyl urea and decreased permeability to water. Al significantly altered the activation energy required to transport water (+ 32%), urea (+ 9%), and monoethyl urea ({minus}7%) across cell membranes. Above 9 C, Al increased the lipidmore » partiality of the cell membranes; below 7 C, Al decreased it. Al narrowed by 6 C the temperature range over which plasmolysis occurred without membrane damage. These changes in membrane behavior are explainable if Al reduced membrane lipid fluidity and kink frequency and increases packing density and the occurrence of straight lipid chains.« less

View of the cinder block milking barn (UT126D) and attached ...

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

View of the cinder block milking barn (UT-126-D) and attached livestock barn (UT-126-B) with large barn (UT-126-A) in the foreground, looking east-northeast - Thomas Powers Ranch, Milking Barn, 4137 North Highway 224, Snyderville, Summit County, UT

The STEAM Project

NASA Astrophysics Data System (ADS)

von Schéele, F.; Steam Team

The proposed satellite project "Stratosphere-Troposphere Exchange And climate Monitor" (STEAM) is dedicated to the investigation of chemical, dynamical, and radiative processes in the upper troposphere and lower stratosphere (UT/LS) altitude range and their links with the Earth climate and stratosphere evolution. The main objectives are to provide vertically and horizontally resolved information on the global distributions of UT/LS key species such as H2O, O3, and CO, and global fields of O3, H2O and halogen compounds responsible for the O3 destruction like ClO in the stratosphere. The UT/LS region plays an important role in the Earth's climate system. Despite its importance there is still a lack of accurate, height-resolved data from the UT/LS. Confronting 3-D climate and chemical-transport models with STEAM observations will improve our knowledge of this atmospheric region. Furthermore, it will be important to continue monitoring the evolution of the stratosphere regarding the expected decline of halogen compounds and recovery of the ozone layer. STEAM consists of a microwave limb-sounding instrument, operating in the 320-360 GHz range to sound the UT/LS and in the 485-505 GHz range to sound the stratosphere, and an optical instrument. By sounding the Earth atmosphere's limb from 5 to 28 km employing a new technique with 8 simultaneous measurements, STEAM will produce a global dataset of UT/LS key species with high vertical (1.5-2.5 km) and horizontal (30-50 km) resolution. The sub-mm band will cover 15 to 40 km. An optical instrument, co-aligned with the mm-wave band, will support micro-wave measurements with cloud indications and in addition provide stratospheric ozone, and aerosol and cloud property measurements. STEAM, planned for a launch in 2008, will be a collaboration between laboratories, industry and agencies in several countries. The Odin heritage of the project (e.g. microwave and optical instruments) provides technical maturity and will help to keep instrument development efforts down. It will also help in the ground-segment development of a 2-D forward and retrieval model and of data assimilation tools. The STEAM mission definition review was held on February 19, concluding the first part of a phase A study. An update of the mission and instrument definitions and the project status will be given at COSPAR.

Effects of dietary urea concentration and zilpaterol hydrochloride on performance and carcass characteristics of finishing steers.

PubMed

Samuelson, K L; Hubbert, M E; Löest, C A

2016-12-01

Cattle receiving zilpaterol hydrochloride () may recycle less N and require a greater supply of RDP. This study evaluated effects of ZH on performance and carcass characteristics of steers fed diets with increasing dietary RDP concentrations supplied as urea. Steers (429 animals; BW = 423 ± 4.5 kg) were sorted into 3 blocks according to BW and assigned to 1 of 6 treatments (6 pens per treatment) in a randomized complete block design. Treatments were a 2 × 3 factorial arrangement of either no ZH or ZH (75 mg ZH per steer daily) supplemented to finishing diets containing 0, 0.5, or 1.0% urea of dietary DM. Pen weights were recorded before treatment initiation; urea was fed for 27 d, and ZH treatments were fed for 24 d with a 3-d withdrawal period. Pen weights were recorded before transporting steers to a commercial abattoir. Continuous response variables were analyzed using the MIXED procedure and categorical data were analyzed using the GLIMMIX procedure of SAS. No ZH × dietary urea interactions ( ≥ 0.14) occurred for all performance and carcass response variables. Feeding ZH for the last 27 d (included a 3-d withdrawal period) of the finishing period increased ( < 0.01) ADG, decreased ( < 0.01) DMI, and increased ( < 0.01) G:F compared with no ZH. In addition, ZH increased HCW ( < 0.01), dressing percentage ( < 0.01), LM area ( < 0.01), and decreased ( = 0.01) yield grade. Increasing dietary urea linearly decreased ( = 0.01) ADG and DMI. A tendency for a linear decrease ( = 0.10) in HCW, and a tendency for a quadratic increase ( = 0.07) in marbling score were observed as urea increased in the diet. Results indicate that cattle supplemented with ZH do not require additional RDP in the diet, and that performance and carcass characteristics were negatively affected when urea was increased in the diet.

Thermal Transport Properties in the Primary Gas-Phase Combustion Zone of Double-Base Propellant: A Sensitivity Study.

DTIC Science & Technology

1986-09-01

26-30, 1964. 17. D.R. Stull and H. Prophet, JANAF Thermochemical Tables, 2nd Ed., NSRDS- NBS-37, June 1957. 18. A.A. Zenin, "Structure of... Dean P.O. Box 48 1 Hercules, Inc. Linden, NJ 07036 Bacchus Works ATTN: K.P. McCarty Ford Aerospace and P.O. Box 98 Communications Corp. Magna, UT 84044

Fuel shipment experience, fuel movements from the BMI-1 transport cask

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

Bauer, Thomas L.; Krause, Michael G

1986-07-01

The University of Texas at Austin received two shipments of irradiated fuel elements from Northrup Aircraft Corporation on April 11 and 16, 1985. A total of 59 elements consisting of standard and instrumented TRIGA fuel were unloaded from the BMI-1 shipping cask. At the time of shipment, the Northrup core burnup was approximately 50 megawatt days with fuel element radiation levels, after a cooling time of three months, of approximately 1.75 rem/hr at 3 feet. In order to facilitate future planning of fuel shipment at the UT facility and other facilities, a summary of the recent transfer process including severalmore » factors which contributed to its success are presented. Numerous color slides were made of the process for future reference by UT and others involved in fuel transfer and handling of the BMI-1 cask.« less

Assessment of the Effects of Plasma Bubbles on GAIM-GM

DTIC Science & Technology

2011-09-01

m / s , 230 m / s was chosen as a realistic upper bound that fit well into the modified IFM grid resolution. The sun...to a second condition where the bubbles would form at 2000 LT and then allowed to super-rotate at 230 m / s , or 7.5 degrees/hr, depicted in Figure 7...moving east at 230 m / s . Units are in TEC electrons per square meter. ( a ) 00UT (b) 01UT (c) 02UT (d) 03 UT (e) 04UT (f) 05UT 1 1 2 1

A Bacillus paralicheniformis Iron-Containing Urease Reduces Urea Concentrations in Rice Wine.

PubMed

Liu, Qingtao; Chen, Yuqi; Yuan, Minglai; Du, Guocheng; Chen, Jian; Kang, Zhen

2017-09-01

Urease, a nickel-containing metalloenzyme, was the first enzyme to be crystallized and has a prominent position in the history of biochemistry. In the present study, we identified a nickel urease gene cluster, ureABCEFGDH , in Bacillus paralicheniformis ATCC 9945a and characterized it in Escherichia coli Enzymatic assays demonstrate that this oxygen-stable urease is also an iron-containing acid urease. Heterologous expression assays of UreH suggest that this accessory protein is involved in the transmembrane transportation of nickel and iron ions. Moreover, this iron-containing acid urease has a potential application in the degradation of urea in rice wine. The present study not only enhances our understanding of the mechanism of activation of urease but also provides insight into the evolution of metalloenzymes. IMPORTANCE An iron-containing, oxygen-stable acid urease from B. paralicheniformis ATCC 9945a with good enzymatic properties was characterized. This acid urease shows activities toward both urea and ethyl carbamate. After digestion with 6 U/ml urease, approximately 92% of the urea in rice wine was removed, suggesting that this urease has great potential in the food industry. Copyright © 2017 American Society for Microbiology.

A Bacillus paralicheniformis Iron-Containing Urease Reduces Urea Concentrations in Rice Wine

PubMed Central

Liu, Qingtao; Chen, Yuqi; Yuan, Minglai; Chen, Jian

2017-01-01

ABSTRACT Urease, a nickel-containing metalloenzyme, was the first enzyme to be crystallized and has a prominent position in the history of biochemistry. In the present study, we identified a nickel urease gene cluster, ureABCEFGDH, in Bacillus paralicheniformis ATCC 9945a and characterized it in Escherichia coli. Enzymatic assays demonstrate that this oxygen-stable urease is also an iron-containing acid urease. Heterologous expression assays of UreH suggest that this accessory protein is involved in the transmembrane transportation of nickel and iron ions. Moreover, this iron-containing acid urease has a potential application in the degradation of urea in rice wine. The present study not only enhances our understanding of the mechanism of activation of urease but also provides insight into the evolution of metalloenzymes. IMPORTANCE An iron-containing, oxygen-stable acid urease from B. paralicheniformis ATCC 9945a with good enzymatic properties was characterized. This acid urease shows activities toward both urea and ethyl carbamate. After digestion with 6 U/ml urease, approximately 92% of the urea in rice wine was removed, suggesting that this urease has great potential in the food industry. PMID:28646111

Reflection coefficient and permeability of urea and ethylene glycol in the human red cell membrane

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

Levitt, D.G.; Mlekoday, H.J.

1983-02-01

The reflection coefficient (sigma) and permeability (P) of urea and ethylene glycol were determined by fitting the equations of Kedem and Katchalsky (1958) to the change in light scattering produced by adding a permeable solute to a red cell suspension. The measurements incorporated three important modifications: (a) the injection artifact was eliminated by using echinocyte cells; (b) the use of an additional adjustable parameter (Km), the effective dissociation constant at the inner side of the membrane; (c) the light scattering is not directly proportional to cell volume (as is usually assumed) because refractive index and scattering properties of the cellmore » depend on the intracellular permeable solute concentration. This necessitates calibrating for known changes in refractive index (by the addition of dextran) and cell volume (by varying the NaCl concentration). The best fit was for sigma . 0.95, Po . 8.3 X 10(-4) cm/s, and Km . 100 mM for urea and sigma . 1.0, Po . 3.9 X 10(-4) cm/s, and Km . 30 mM for ethylene glycol. The effects of the inhibitors copper, phloretin, p-chloromercuriphenylsulfonate, and 5,5'-dithiobis (2-nitro) benzoic acid on the urea, ethylene glycol, and water permeability were determined. The results suggest that there are three separate, independent transport systems: one for water, one for urea and related compounds, and one for ethylene glycol and glycerol.« less

The effect of urea on microstructures of Ni{sub 3}S{sub 2} on nickel foam and its hydrogen evolution reaction

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

Jinlong, Lv, E-mail: ljltsinghua@126.com; State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084; Tongxiang, Liang, E-mail: txliang@mail.tsinghua.edu.cn

The effects of urea concentration on microstructures of Ni{sub 3}S{sub 2}formed on nickel foam and its hydrogen evolution reaction were investigated. The Ni{sub 3}S{sub 2} nanosheets with porous structure were formed on nickel foam during hydrothermal process due to low urea concentration. While high urea concentration facilitated the forming of Ni{sub 3}S{sub 2} nanotube arrays. The resulting Ni{sub 3}S{sub 2} nanotube arrays exhibited higher catalytic activity than Ni3S2nanosheets for hydrogen evolution reaction. This was mainly attributed to a fact that Ni{sub 3}S{sub 2} nanotube arrays facilitated diffusion of electrolyte for hydrogen evolution reaction. - Graphical abstract: The resulting Ni{sub 3}S{submore » 2} nanotube arrays exhibited higher catalytic activity than Ni{sub 3}S{sub 2} nanosheets for hydrogen evolution reaction. This was mainly attributed to a fact that Ni{sub 3}S{sub 2} nanotube arrays facilitated diffusion of electrolyte for hydrogen evolution reaction and hydrogen evolution. - Highlights: • Urea promoted to forming more Ni{sub 3}S{sub 2} nanotube arrays on nickel foam. • Ni{sub 3}S{sub 2} nanotube arrays showed higher catalytic activity in alkaline solution. • Ni{sub 3}S{sub 2} nanotube arrays promoted electron transport and reaction during the HER.« less

Introduction to the SONEX (Subsonic Assessment Ozone and Nitrogen Oxides Experiment) and POLINAT-2 (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) Special Issue

NASA Technical Reports Server (NTRS)

Thompson, Anne M.; Singh, Hanwant B.; Schlager, Hans; Einaudi, Franco (Technical Monitor)

2000-01-01

Emissions of atmospheric species from the engines of subsonic aircraft at cruise altitude (roughly, above seven kilometers) are of concern to scientists, the aviation industry and policymakers for two reasons. First, water vapor, soot and sulfur oxides, and related heterogeneous processes, may modify clouds and aerosols enough to perturb radiative forcing in the UT/LS (upper troposphere/lower stratosphere). A discussion of these phenomena appears in Chapter 3 of the IPCC Aviation Assessment (1999). An airborne campaign conducted to evaluate aviation effects on contrail, cirrus and cloud formation, is described in Geophysical Research Letters. The second concern arises from subsonic aircraft emissions of nitrogen oxides (NO + NO2 = NO(sub x)), CO, and hydrocarbons. These species may add to the background mixture of photochemically reactive species that form ozone. In the UT/LS, ozone is a highly effective greenhouse gas. The impacts of subsonic aircraft emissions on tropospheric NO(sub x) and ozone budgets have been studied with models that focus on UT chemistry [e.g. see discussions of individual models in Brasseur et al., 1998; Friedl et al., 1997; IPCC, 1999]. Depending on the model used, projected increases in the global subsonic aircraft fleet from 1992 to 2015 will lead to a 50-100 pptv increase in UT/LS NO. at 12 km (compared to 50-150 pptv background) in northern hemisphere midlatitudes. The corresponding 12-km ozone increase is 7-11 ppbv, or 5-10% (Chapter 4 in IPCC, 1999). Two major sources of uncertainties in model estimates of aviation effects are: (1) the often limited degree to which global models - the scale required to evaluate aircraft emissions - realistically simulate atmospheric transport and other physical processes; (2) limited UT/LS observations of trace gases with which to evaluate model performance. In response to the latter deficiency, a number of airborne campaigns aimed at elucidating the effect of aircraft on atmospheric nitrogen oxides and ozone were performed between 1990 and 1996 (see descriptions in Friedl et al., 1997; Brasseur et al., 1998).

A Comprehensive Study on the Internet of Underwater Things: Applications, Challenges, and Channel Models †

PubMed Central

Wu, Geng-De; Huang, Chun-Ju

2017-01-01

The Internet of Underwater Things (IoUT) is a novel class of Internet of Things (IoT), and is defined as the network of smart interconnected underwater objects. IoUT is expected to enable various practical applications, such as environmental monitoring, underwater exploration, and disaster prevention. With these applications, IoUT is regarded as one of the potential technologies toward developing smart cities. To support the concept of IoUT, Underwater Wireless Sensor Networks (UWSNs) have emerged as a promising network system. UWSNs are different from the traditional Territorial Wireless Sensor Networks (TWSNs), and have several unique properties, such as long propagation delay, narrow bandwidth, and low reliability. These unique properties would be great challenges for IoUT. In this paper, we provide a comprehensive study of IoUT, and the main contributions of this paper are threefold: (1) we introduce and classify the practical underwater applications that can highlight the importance of IoUT; (2) we point out the differences between UWSNs and traditional TWSNs, and these differences are the main challenges for IoUT; and (3) we investigate and evaluate the channel models, which are the technical core for designing reliable communication protocols on IoUT. PMID:28640220

A Comprehensive Study on the Internet of Underwater Things: Applications, Challenges, and Channel Models.

PubMed

Kao, Chien-Chi; Lin, Yi-Shan; Wu, Geng-De; Huang, Chun-Ju

2017-06-22

The Internet of Underwater Things (IoUT) is a novel class of Internet of Things (IoT), and is defined as the network of smart interconnected underwater objects. IoUT is expected to enable various practical applications, such as environmental monitoring, underwater exploration, and disaster prevention. With these applications, IoUT is regarded as one of the potential technologies toward developing smart cities. To support the concept of IoUT, Underwater Wireless Sensor Networks (UWSNs) have emerged as a promising network system. UWSNs are different from the traditional Territorial Wireless Sensor Networks (TWSNs), and have several unique properties, such as long propagation delay, narrow bandwidth, and low reliability. These unique properties would be great challenges for IoUT. In this paper, we provide a comprehensive study of IoUT, and the main contributions of this paper are threefold: (1) we introduce and classify the practical underwater applications that can highlight the importance of IoUT; (2) we point out the differences between UWSNs and traditional TWSNs, and these differences are the main challenges for IoUT; and (3) we investigate and evaluate the channel models, which are the technical core for designing reliable communication protocols on IoUT.

Constraints from Airborne (210)Pb Observations on Aerosol Scavenging and Lifetime in a Global Chemical Transport Model

NASA Technical Reports Server (NTRS)

Zhang, Bo; Liu, Hongyu; Crawford, James H.; Fairlie, Duncan T.; Chen, Gao; Dibb, Jack E.; Shah, Viral; Sulprizio, Melissa P.; Yantosca, Robert M.

2016-01-01

Lead-210 distribution and lifetime in the atmosphere are not sensitive to ice in-cloud scavenging in convective updraft. Ice in-cloud scavenging in stratiform clouds reduce tropospheric (210)Pb lifetime by approximately 1 day and results in better agreements with observed surface observations and aircraft measured profiles. However, the process results in significant underestimate of (210)Pb in UT/LS.

A tonoplast intrinsic protein in Gardenia jasminoides

NASA Astrophysics Data System (ADS)

Gao, Lan; Li, Hao-Ming

2017-08-01

Physiological and molecular studies proved that plasma membrane intrinsic proteins (PIPs) and tonoplast intrinsic proteins (TIPs) subfamily of aquaporins play key functions in plant water homeostasis. Five specialized subgroups (TIP1-5) of TIPs have been found in higher plants, in which the TIP1 and TIP2 isoforms are the largest arbitrary groups. TIPs have high water-transport activity than PIPs, some TIPs can transport other small molecule such as urea, ammonia, hydrogen peroxide, and carbon dioxide. In this work, the structure of the putative tonoplast aquaporin from Gardenia jasminoides (GjTIP) was analyzed. Its transcript level has increased during fruit maturation. A phylogenetic analysis indicates that the protein belongs to TIP1 subfamily. A three-dimensional model structure of GjTIP was built based on crystal structure of an ammonia-permeable AtTIP2-1 from Arabidopsis thaliana. The model structure displayed as a homo-tetramer, each monomer has six trans-membrane and two half-membrane-spanning α helices. The data suggests that the GjTIP has tendency to be a mixed function aquaporin, might involve in water, urea and hydrogen peroxide transport, and the gating machanism founded in some AQPs involving pH and phosphorylation response have not been proved in GjTIP.

Effect of abomasal infusion of oligofructose on portal-drained visceral ammonia and urea-nitrogen fluxes in lactating Holstein cows.

PubMed

Røjen, B A; Larsen, M; Kristensen, N B

2012-12-01

The effects of abomasal infusion of oligofructose in lactating dairy cows on the relationship between hindgut fermentation and N metabolism, and its effects on NH(3) absorption and transfer of blood urea-N across the portal-drained viscera versus ruminal epithelia were investigated. Nine lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in major splanchnic blood vessels were used in an unbalanced crossover design with 14-d periods. Treatments were continuous abomasal infusion of water or 1,500 g/d of oligofructose. The same basal diet was fed with both treatments. Eight sample sets of arterial, portal, hepatic, and ruminal vein blood, ruminal fluid, and urine were obtained at 0.5h before the morning feeding and at 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, and 6.5 h after feeding. It was hypothesized that an increased supply of fermentable substrate to the hindgut would increase the uptake of urea-N from blood to the hindgut at the expense of urea-N uptake to the forestomach. The study showed that abomasal oligofructose infusion decreased the total amount of urea-N transferred from the blood to the gut, NH(3) absorption, and arterial blood urea-N concentration. Subsequently, hepatic NH(3) uptake and urea-N production also decreased with oligofructose infusion. Additionally, urea-N concentration in milk and urinary N excretion decreased with oligofructose treatment. The oligofructose infusion did not affect ruminal NH(3) concentrations or any other ruminal variables, nor did it affect ruminal venous - arterial concentration differences for urea-N and NH(3). The oligofructose treatment did not affect milk yield, but did decrease apparent digestibility of OM, N, and starch. Nitrogen excreted in the feces was greater with the oligofructose infusion. In conclusion, the present data suggest that increased hindgut fermentation did not upregulate urea-N transfer to the hindgut at the expense of urea-N uptake by the rumen, and the observed reduction in arterial blood urea-N concentration appeared not to be due to increased urea-N transport, but rather could be explained by reduced NH(3) input to hepatic urea-N synthesis caused by increased sequestration of NH(3) in the hindgut and excretion in feces. Increasing the hindgut fermentation in lactating dairy cows by abomasal infusion of 1,500 g/d of oligofructose shifted some N excretion from the urine to feces and possibly reduced manure NH(3) volatilization without impairing rumen fermentation. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Ultra-Rapid dUT1 Measurements on Japan-Fennoscandian Baselines - Application to 24-hour Sessions

NASA Technical Reports Server (NTRS)

Matsuzaka, Shigeru; Kurihara, Shinobu; Sekido, Mamoru; Hobiger, Thomas; Haas, Rudiger; Ritakari, Jouko; Wagner, Jan

2010-01-01

GSI, NICT, OSO, and MRO have been engaged in Ultra-rapid dUT1 experiments since 2007 aiming at the technological possibility of real-time dUT1 results using the e-VLBI technique. We have already successfully determined dUT1 in less than four minutes after the end of an experimental Intensive session in 2008, and at present we routinely get the results within 30 minutes for regular Intensives. In 2009 we applied the technique to 24-hour sessions and continuously obtained dUT1 values by processing and analyzing Tsukuba Onsala data in near real-time. It showed a detailed behavior of UT1 variations, which could be very valuable for scientific study as well as for precise prediction of UT1-UTC.

Unconventional Constraints on Nitrogen Chemistry using DC3 Observations and Trajectory-based Chemical Modeling

NASA Astrophysics Data System (ADS)

Shu, Q.; Henderson, B. H.

2017-12-01

Chemical transport models underestimate nitrogen dioxide observations in the upper troposphere (UT). Previous research in the UT succeeded in combining model predictions with field campaign measurements to demonstrate that the nitric acid formation rate (HO + NO2 → HNO3 (R1)) is overestimated by 22% (Henderson et al., 2012). A subsequent publication (Seltzer et al., 2015) demonstrated that single chemical constraint alters ozone and aerosol formation/composition. This work attempts to replicate previous chemical constraints with newer observations and a different modeling framework. We apply the previously successful constraint framework to Deep Convection Clouds and Chemistry (DC3). DC3 is a more recent field campaign where simulated nitrogen imbalances still exist. Freshly convected air parcels, identified in the DC3 dataset, as initial coordinates to initiate Lagrangian trajectories. Along each trajectory, we simulate the air parcel chemical state. Samples along the trajectories will form ensembles that represent possible realizations of UT air parcels. We then apply Bayesian inference to constrain nitrogen chemistry and compare results to the existing literature. Our anticipated results will confirm overestimation of HNO3 formation rate in previous work and provide further constraints on other nitrogen reaction rate coefficients that affect terminal products from NOx. We will particularly focus on organic nitrate chemistry that laboratory literature has yet to fully address. The results will provide useful insights into nitrogen chemistry that affects climate and human health.

Quantitative RT-PCR Comparison of the Urea and Nitric Oxide Cycle Gene Transcripts in Adult Human Tissues

PubMed Central

Neill, Meaghan Anne; Aschner, Judy; Barr, Frederick; Summar, Marshall L.

2009-01-01

The urea cycle and nitric oxide cycle play significant roles in complex biochemical and physiologic reactions. These cycles have distinct biochemical goals including the clearance of waste nitrogen; the production of the intermediates ornithine, citrulline, and arginine for the urea cycle; and the production of nitric oxide for the nitric oxide pathway. Despite their disparate functions, the two pathways share two enzymes, argininosuccinic acid synthase and argininosuccinic acid lyase, and a transporter, citrin. Studying the gene expression of these enzymes is paramount in understanding these complex biochemical pathways. Here, we examine the expression of genes involved in the urea cycle and the nitric oxide cycle in a panel of eleven different tissue samples obtained from individual adults without known inborn errors of metabolism. In this study, the pattern of co-expressed enzymes provides a global view of the metabolic activity of the urea and nitric oxide cycles in human tissues. Our results show that these transcripts are differentially expressed in different tissues. The pattern of co-expressed enzymes provides a global view of the metabolic activity of the urea and nitric oxide cycles in human tissues. Using the co-expression profiles, we discovered that the combination of expression of enzyme transcripts as detected in our study, might serve to fulfill specific physiologic function(s) in tissue including urea production/nitrogen removal, arginine/citrulline production, nitric oxide production, and ornithine production. Our study reveals the importance of studying not only the expression profile of an enzyme of interest, but also studying the expression profiles of the other enzymes involved in a particular pathway so as to better understand the context of expression. The tissue patterns we observed highlight the variety of important functions they conduct and provide insight into many of the clinical observations from their disruption. PMID:19345634

H+, Water and Urea Transport in the Inner Medullary Collecting Duct and Their Role in the Prevention and Pathogenesis of Renal Stone Disease

NASA Astrophysics Data System (ADS)

Wall, Susan M.; Klein, Janet D.

2008-09-01

The inner medullary collecting duct (IMCD) is the final site within the kidney for the reabsorption of urea, water and electrolytes and for the secretion of H+ before the luminal fluid becomes the final urine. Transporters expressed in the IMCD contribute to the generation of the large ion gradients that exist between the interstitium and the collecting duct lumen. Thus, the luminal fluid within the human IMCD can reach an osmolality of 1200 mOsm/kg H2O and a pH of 4. This ability of the human nephron to concentrate and acidify the urine might predispose to stone formation. However, under treatment conditions that predispose to stone formation, such as during hypercalciuria, the kidney mitigates stone formation by reducing solute concentration by reducing H2O reabsorption. Moreover, the kidney attenuates stone formation by tightly controlling acid-base balance, which prevents the bone loss, hypocitraturia and hypercalciuria observed during metabolic acidosis by augmenting net H+ excretion by tightly regulating H+ transporter function and through luminal buffering, particularly with NH3. This article will review the ion transporters present in the mammalian IMCD and their role in the prevention and in the pathogenesis of renal stone formation.

Serotyping reanalysis of unserotypable Actinobacillus pleuropneumoniae isolates by agar gel diffusion test.

PubMed

Morioka, Ayako; Shimazaki, Yoko; Uchiyama, Mariko; Suzuki, Shoko

2016-05-03

We observed increasing unserotypable (UT) Actinobacillus pleuropneumoniae isolates using agar gel diffusion (AGD) test. To reanalyze their serovar, we performed rapid slide agglutination (RSA) test and multiplex PCR for 47 UT isolates. Of these, 25 were serovar 1 (UT-serovar 1), 20 were serovar 2 (UT-serovar 2) and 2 were serovar 15 (UT-serovar 15). We examined serotyping antigen extraction temperature to determine heat influence. UT-serovar 1 and 15 were influenced by heat, because their precipitation lines were observed in the case of low antigen extraction temperature. To investigate the relationship between antigenicity and genotype, we performed pulsed-field gel electrophoresis (PFGE) analysis using UT-serovar 2 and 15. The predominant PFGE pattern of UT-serovar 2 was identical to that of serovar 2.

Serotyping reanalysis of unserotypable Actinobacillus pleuropneumoniae isolates by agar gel diffusion test

PubMed Central

MORIOKA, Ayako; SHIMAZAKI, Yoko; UCHIYAMA, Mariko; SUZUKI, Shoko

2016-01-01

We observed increasing unserotypable (UT) Actinobacillus pleuropneumoniae isolates using agar gel diffusion (AGD) test. To reanalyze their serovar, we performed rapid slide agglutination (RSA) test and multiplex PCR for 47 UT isolates. Of these, 25 were serovar 1 (UT-serovar 1), 20 were serovar 2 (UT-serovar 2) and 2 were serovar 15 (UT-serovar 15). We examined serotyping antigen extraction temperature to determine heat influence. UT-serovar 1 and 15 were influenced by heat, because their precipitation lines were observed in the case of low antigen extraction temperature. To investigate the relationship between antigenicity and genotype, we performed pulsed-field gel electrophoresis (PFGE) analysis using UT-serovar 2 and 15. The predominant PFGE pattern of UT-serovar 2 was identical to that of serovar 2. PMID:26726101

Middle and long-term prediction of UT1-UTC based on combination of Gray Model and Autoregressive Integrated Moving Average

NASA Astrophysics Data System (ADS)

Jia, Song; Xu, Tian-he; Sun, Zhang-zhen; Li, Jia-jing

2017-02-01

UT1-UTC is an important part of the Earth Orientation Parameters (EOP). The high-precision predictions of UT1-UTC play a key role in practical applications of deep space exploration, spacecraft tracking and satellite navigation and positioning. In this paper, a new prediction method with combination of Gray Model (GM(1, 1)) and Autoregressive Integrated Moving Average (ARIMA) is developed. The main idea is as following. Firstly, the UT1-UTC data are preprocessed by removing the leap second and Earth's zonal harmonic tidal to get UT1R-TAI data. Periodic terms are estimated and removed by the least square to get UT2R-TAI. Then the linear terms of UT2R-TAI data are modeled by the GM(1, 1), and the residual terms are modeled by the ARIMA. Finally, the UT2R-TAI prediction can be performed based on the combined model of GM(1, 1) and ARIMA, and the UT1-UTC predictions are obtained by adding the corresponding periodic terms, leap second correction and the Earth's zonal harmonic tidal correction. The results show that the proposed model can be used to predict UT1-UTC effectively with higher middle and long-term (from 32 to 360 days) accuracy than those of LS + AR, LS + MAR and WLS + MAR.

Nitrogen recycling through the gut and the nitrogen economy of ruminants: an asynchronous symbiosis.

PubMed

Reynolds, C K; Kristensen, N B

2008-04-01

The extensive development of the ruminant forestomach sets apart their N economy from that of nonruminants in a number of respects. Extensive pregastric fermentation alters the profile of protein reaching the small intestine, largely through the transformation of nitrogenous compounds into microbial protein. This process is fueled primarily by carbohydrate fermentation and includes extensive recycling of N between the body and gut lumen pools. Nitrogen recycling occurs via blood and gut lumen exchanges of urea and NH(3), as well as endogenous gut and secretory N entry into the gut lumen, and the subsequent digestion and absorption of microbial and endogenous protein. Factors controlling urea transfer to the gut from blood, including the contributions of urea transporters, remain equivocal. Ammonia produced by microbial degradation of urea and dietary and endogenous AA is utilized by microbial fermentation or absorbed and primarily converted to urea. Therefore, microbial growth and carbohydrate fermentation affect the extent of NH(3) absorption and urea N recycling and excretion. The extensive recycling of N to the rumen represents an evolutionary advantage of the ruminant in terms of absorbable protein supply during periods of dietary protein deficiency, or asynchronous carbohydrate and protein supply, but incurs a cost of greater N intakes, especially in terms of excess N excretion. Efforts to improve the efficiency of N utilization in ruminants by synchronizing fermentable energy and N availability have generally met with limited success with regards to production responses. In contrast, imposing asynchrony through oscillating dietary protein concentration, or infrequent supplementation, surprisingly has not negatively affected production responses unless the frequency of supplementation is less than once every 3 d. In some cases, oscillation of dietary protein concentration has improved N retention compared with animals fed an equal amount of dietary protein on a daily basis. This may reflect benefits of Orn cycle adaptations and sustained recycling of urea to the gut. The microbial symbiosis of the ruminant is inherently adaptable to asynchronous N and energy supply. Recycling of urea to the gut buffers the effect of irregular dietary N supply such that intuitive benefits of rumen synchrony in terms of the efficiency of N utilization are typically not observed in practice.

Estimated dissolved-solids loads and trends at selected streams in and near the Uinta Basin, Utah, Water Years 1989–2013

USGS Publications Warehouse

Thiros, Susan A.

2017-03-23

The U.S. Geological Survey (USGS), in cooperation with the Colorado River Basin Salinity Control Forum, studied trends in dissolved-solids loads at selected sites in and near the Uinta Basin, Utah. The Uinta Basin study area includes the Duchesne River Basin and the Middle Green River Basin in Utah from below Flaming Gorge Reservoir to the town of Green River.Annual dissolved-solids loads for water years (WY) 1989 through 2013 were estimated for 16 gaging stations in the study area using streamflow and water-quality data from the USGS National Water Information System database. Eight gaging stations that monitored catchments with limited or no agricultural land use (natural subbasins) were used to assess loads from natural sources. Four gaging stations that monitored catchments with agricultural land in the Duchesne River Basin were used to assess loads from agricultural sources. Four other gaging stations were included in the dissolved-solids load and trend analysis to help assess the effects of agricultural areas that drain to the Green River in the Uinta Basin, but outside of the Duchesne River Basin.Estimated mean annual dissolved-solids loads for WY 1989–2013 ranged from 1,520 tons at Lake Fork River above Moon Lake, near Mountain Home, Utah (UT), to 1,760,000 tons at Green River near Green River, UT. The flow-normalized loads at gaging stations upstream of agricultural activities showed no trend or a relatively small change. The largest net change in modeled flow-normalized load was -352,000 tons (a 17.8-percent decrease) at Green River near Green River, UT.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.The flow-normalized dissolved-solids loads estimated at Duchesne River near Randlett, UT, and White River near Watson, UT, decreased by 68,000 and 55,300 tons, or 27.8 and 20.8 percent respectively, when comparing 1989 to 2013. The drainage basins for both rivers have undergone salinity-control projects since the early 1980s to reduce the dissolved-solids load entering the Colorado River. Approximately 19 percent of the net change in flow-normalized load at Green River at Green River, UT, is from changes in load modeled at Duchesne River near Randlett, UT, and 16 percent from changes in load modeled at White River near Watson, UT. The net change in flow-normalized load estimated at Green River near Greendale, UT, for WY 1989–2013 accounts for about 45 percent of the net change estimated at Green River at Green River, UT.Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites in the Duchesne River Basin show that 75,400 tons or 44 percent of the load at the Duchesne River near Randlett, UT, gaging station was not accounted for at any of the upstream gages. Most of this unmonitored load is derived from tributary inflow, groundwater discharge, unconsumed irrigation water, and irrigation tail water.A mass balance of WY 1989–2013 flow-normalized loads estimated at sites in the Duchesne River Basin indicates that the flow-normalized load of unmonitored inflow to the Duchesne River between the Myton and Randlett gaging stations decreased by 38 percent. The total net decrease in flow-normalized load calculated for unmonitored inflow in the drainage basin accounts for 94 percent of the decrease in WY 1989–2013 flow-normalized load modeled at the Duchesne River near Randlett, UT, gaging station. Irrigation improvements in the drainage basin have likely contributed to the decrease in flow-normalized load.Reductions in dissolved-solids load estimated by the Natural Resources Conservation Service (NRCS) and the Bureau of Reclamation (Reclamation) from on- and off-farm improvements in the Uinta Basin totaled about 135,000 tons in 2013 (81,900 tons from on-farm improvements and 53,300 tons from off-farm improvements). The reduction in dissolved-solids load resulting from on- and off-farm improvements facilitated by the NRCS and Reclamation in the Price River Basin from 1989 to 2013 was estimated to be 64,800 tons.The amount of sprinkler-irrigated land mapped in the drainage area or subbasin area for a gaging station was used to estimate the reduction in load resulting from the conversion from flood to sprinkler irrigation. Sprinkler-irrigated land mapped in the Uinta Basin totaled 109,630 acres in 2012. Assuming conversion to wheel-line sprinklers, a reduction in dissolved-solids load in the Uinta Basin of 95,800 tons in 2012 was calculated using the sprinkler-irrigation acreage and a pre-salinity-control project dissolved-solids yield of 1.04 tons per acre.A reduction of 72,800 tons in dissolved-solids load from irrigation improvements was determined from sprinkler-irrigated lands in the Ashley Valley and Jensen, Pelican Lake, and Pleasant Valley areas (mapped in 2012); and in the Price River Basin (mapped in 2011). This decrease in dissolved-solids load is 8,800 tons more than the decrease in unmonitored flow-normalized dissolved-solids load (-64,000 tons) determined for the Green River between the Jensen and Green River gaging stations.The net WY 1989–2013 change in flow-normalized dissolved-solids load at the Duchesne River near Randlett, UT, and the Green River between the Jensen and Green River, UT, gaging stations determined from mass-balance calculations was compared to reported reductions in dissolved-solids load from on- and off-farm improvements and estimated reductions in load determined from mapped sprinkler-irrigated areas in the Duchesne River Basin and the area draining to the Green River between the Jensen and Green River gaging stations. The combined NRCS and Reclamation estimates of reduction in dissolved-solids load from on- and off-farm improvements in the study area (200,000 tons) is more than the reduction in load estimated using the acreage with sprinkler improvements (136,000 tons) or the mass-balance of flow-normalized load (132,000 tons).

Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi).

PubMed

Giacomin, Marina; Schulte, Patricia M; Wood, Chris M

Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi. We hypothesized that as metabolic demand for oxygen increased with temperature, the fluxes of ammonia, urea-N, and 3 H 2 O at the gills would increase in parallel with those of oxygen. Oxygen consumption (overall [Formula: see text] from 7.5° to 22°C) and water fluxes (overall [Formula: see text]) responded to increases in temperature in a similar, almost linear, manner. Ammonia-N efflux rates varied the most, increasing almost 15-fold from 7.5° to 22°C ([Formula: see text]). Urea-N efflux was tightly conserved over the 7.5°-15°C range ([Formula: see text]) but increased greatly at higher temperatures, yielding an overall [Formula: see text]. These differences likely reflect differences in the transport pathways for the four moieties. They also suggest the failure of urea-N- and ammonia-N-conserving mechanisms at the gill above 15°C. Hyperoxia did not alleviate the effects of high temperature. Indeed, urea-N and ammonia-N effluxes were dramatically increased when animals were exposed to high temperatures in the presence of hyperoxia, suggesting that high partial pressure of oxygen may have caused oxidative damage to gill epithelial membranes.

High-level expression of human stem cell factor fused with erythropoietin mimetic peptide in Escherichia coli.

PubMed

Su, Lin; Chen, Song-Sen; Yang, Ke-Gong; Liu, Chang-Zheng; Zhang, Yan-Li; Liang, Zhi-Quan

2006-06-01

Stem cell factor (SCF) and erythropoietin are essential for normal erythropoiesis and induce proliferation and differentiation synergistically for erythroid progenitor cells. Here, we report our work on construction of SCF/erythropoietin mimetic peptide (EMP) fusion protein gene, in which human SCF cDNA (1-165aa) and EMP sequence (20aa) were connected using a short (GGGGS) or long (GGGGSGGGGGS) linker sequence. The SCF/EMP gene was cloned into the pBV220 vector and expressed in the Escherichia coli DH5alpha strain. The expression level of the fusion protein was about 30% of total cell protein. The resulting inclusion bodies were solubilized with 8 M urea, followed by dilution refolding. The renatured protein was subsequently purified by Q-Sepharose FF column. The final product was >95% pure by SDS-PAGE and the yield of fusion protein was about 40 mg/L of culture. UT-7 cell proliferation and human cord blood cell colony-forming assays showed that the fusion proteins exhibited more potent activity than recombinant human SCF, suggesting a new strategy to enhance biological activities of growth factors.

Deletion of the UT receptor gene results in the selective loss of urotensin-II contractile activity in aortae isolated from UT receptor knockout mice

PubMed Central

Behm, David J; Harrison, Stephen M; Ao, Zhaohui; Maniscalco, Kristeen; Pickering, Susan J; Grau, Evelyn V; Woods, Tina N; Coatney, Robert W; Doe, Christopher P A; Willette, Robert N; Johns, Douglas G; Douglas, Stephen A

2003-01-01

Urotensin-II (U-II) is among the most potent mammalian vasoconstrictors identified and may play a role in the aetiology of essential hypertension. Currently, only one mouse U-II receptor (UT) gene has been cloned. It is postulated that this protein is solely responsible for mediating U-II-induced vasoconstriction. This hypothesis has been investigated in the present study, which assessed basal haemodynamics and vascular reactivity to hU-II in wild-type (UT(+/+)) and UT receptor knockout (UT(−/−)) mice. Basal left ventricular end-diastolic and end-systolic volumes/pressures, stroke volumes, mean arterial blood pressures, heart rates, cardiac outputs and ejection fractions in UT(+/+) mice and in UT(−/−) mice were similar. Relative to UT(+/+) mouse isolated thoracic aorta, where hU-II was a potent spasmogen (pEC50=8.26±0.08) that evoked relatively little vasoconstriction (17±2% 60 mM KCl), vessels isolated from UT(−/−) mice did not respond to hU-II. However, in contrast, the superior mesenteric artery isolated from both the genotypes did not contract in the presence of hU-II. Reactivity to unrelated vasoconstrictors (phenylephrine, endothelin-1, KCl) and endothelium-dependent/independent vasodilator agents (carbachol, sodium nitroprusside) was similar in the aorta and superior mesenteric arteries isolated from both the genotypes. The present study is the first to directly link hU-II-induced vasoconstriction with the UT receptor. Deletion of the UT receptor gene results in loss of hU-II contractile action with no ‘nonspecific' alterations in vascular reactivity. However, as might be predicted based on the limited contractile efficacy recorded in vitro, the contribution that hU-II and its receptor make to basal systemic haemodynamics appears to be negligible in this species. PMID:12770952

The Effects of Pulsed Radiation Therapy on Tumor Oxygenation in 2 Murine Models of Head and Neck Squamous Cell Carcinoma

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

Wobb, Jessica; Krueger, Sarah A.; Kane, Jonathan L.

2015-07-15

Purpose: To evaluate the efficacy of low-dose pulsed radiation therapy (PRT) in 2 head and neck squamous cell carcinoma (HNSCC) xenografts and to investigate the mechanism of action of PRT compared with standard radiation therapy (SRT). Methods and Materials: Subcutaneous radiosensitive UT-SCC-14 and radioresistant UT-SCC-15 xenografts were established in athymic NIH III HO female mice. Tumors were irradiated with 2 Gy/day by continuous standard delivery (SRT: 2 Gy) or discontinuous low-dose pulsed delivery (PRT: 0.2 Gy × 10 with 3-min pulse interval) to total doses of 20 Gy (UT14) or 40 Gy (UT15) using a clinical 5-day on/2-day off schedule. Treatment response was assessed by changes inmore » tumor volume, {sup 18}F-fluorodeoxyglucose (FDG) (tumor metabolism), and {sup 18}F-fluoromisonidazole (FMISO) (hypoxia) positron emission tomography (PET) imaging before, at midpoint, and after treatment. Tumor hypoxia using pimonidazole staining and vascular density (CD34 staining) were assessed by quantitative histopathology. Results: UT15 and UT14 tumors responded similarly in terms of growth delay to either SRT or PRT. When compared with UT14 tumors, UT15 tumors demonstrated significantly lower uptake of FDG at all time points after irradiation. UT14 tumors demonstrated higher levels of tumor hypoxia after SRT when compared with PRT as measured by {sup 18}F-FMISO PET. By contrast, no differences were seen in {sup 18}F-FMISO PET imaging between SRT and PRT for UT15 tumors. Histologic analysis of pimonidazole staining mimicked the {sup 18}F-FMISO PET imaging data, showing an increase in hypoxia in SRT-treated UT14 tumors but not PRT-treated tumors. Conclusions: Differences in {sup 18}F-FMISO uptake for UT14 tumors after radiation therapy between PRT and SRT were measurable despite the similar tumor growth delay responses. In UT15 tumors, both SRT and PRT were equally effective at reducing tumor hypoxia to a significant level as measured by {sup 18}F-FMISO and pimonidazole.« less

Investigating Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

NASA Technical Reports Server (NTRS)

Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

2016-01-01

High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOSchem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7% and 7.6%, respectively) compared to that from LT (64.1%), but the relative ozone concentration coming from LS and UT is high (38.4% and 20.95%, respectively) compared to that from LT (17.7%). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

Investigation of Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

NASA Technical Reports Server (NTRS)

Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

2015-01-01

High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOS-chem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7 and 7.6, respectively) compared to that from LT (64.1), but the relative ozone concentration coming from LS and UT is high (38.4 and 20.95, respectively) compared to that from LT (17.7). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

Learning Multirobot Hose Transportation and Deployment by Distributed Round-Robin Q-Learning.

PubMed

Fernandez-Gauna, Borja; Etxeberria-Agiriano, Ismael; Graña, Manuel

2015-01-01

Multi-Agent Reinforcement Learning (MARL) algorithms face two main difficulties: the curse of dimensionality, and environment non-stationarity due to the independent learning processes carried out by the agents concurrently. In this paper we formalize and prove the convergence of a Distributed Round Robin Q-learning (D-RR-QL) algorithm for cooperative systems. The computational complexity of this algorithm increases linearly with the number of agents. Moreover, it eliminates environment non sta tionarity by carrying a round-robin scheduling of the action selection and execution. That this learning scheme allows the implementation of Modular State-Action Vetoes (MSAV) in cooperative multi-agent systems, which speeds up learning convergence in over-constrained systems by vetoing state-action pairs which lead to undesired termination states (UTS) in the relevant state-action subspace. Each agent's local state-action value function learning is an independent process, including the MSAV policies. Coordination of locally optimal policies to obtain the global optimal joint policy is achieved by a greedy selection procedure using message passing. We show that D-RR-QL improves over state-of-the-art approaches, such as Distributed Q-Learning, Team Q-Learning and Coordinated Reinforcement Learning in a paradigmatic Linked Multi-Component Robotic System (L-MCRS) control problem: the hose transportation task. L-MCRS are over-constrained systems with many UTS induced by the interaction of the passive linking element and the active mobile robots.

Movie Smoking, Movie Horror, and Urge to Smoke

PubMed Central

SARGENT, James D.; MARUSKA, Karin; MORGENSTERN, Matthis; ISENSEE, Barbara; HANEWINKEL, Reiner

2010-01-01

It is known that exposure to smoking cues increases urge to smoke (UTS), but little is known about other media factors that might also increase UTS. We hypothesized that horror/thriller movies might also increase UTS by increasing negative affect. We surveyed 536 movie patrons who were smokers aged 18 years or older. Subjects had exited 26 movies, of which 12 contained smoking and two were horror films, one with and one without smoking. We used random effects regression to assess the association between exposure to movie smoking, movie horror, both and UTS, controlling for confounding factors. Median age was 26 years and 52% were female. Mean UTS was 5.9, 6.6, 6.6, and 8.7 for smokers exiting movies without smoking, with smoking, horror without smoking and horror with smoking respectively. Smoking in movies was associated with a significantly higher UTS (0.63 [95% CI 0.31–0.94]). Horror with smoking increased UTS by 2.8 points (95% C.I. 2.3, 3.5); the horror without smoking estimate was 0.88, but not statistically significant. This short report offers preliminary evidence that movie horror as one factor besides visual smoking cues that could increase UTS in a community setting. PMID:20301876

Movie smoking, movie horror, and urge to smoke.

PubMed

Sargent, James D; Maruska, Karin; Morgenstern, Matthis; Isensee, Barbara; Hanewinkel, Reiner

2009-01-01

It is known that exposure to smoking cues increases urge to smoke (UTS), but little is known about other media factors that might also increase UTS. We hypothesized that horror/ thriller movies might also increase UTS by increasing negative affect. We surveyed 536 movie patrons who were smokers aged 18 years or older. Subjects had exited 26 movies, of which 12 contained smoking and two were horrorfilms, one with and one without smoking. We used random effects regression to assess the association between exposure to movie smoking, movie horror, both and UTS, controlling for confounding factors. Median age was 26 years and 52% were female. Mean UTS was 5.9, 6.6, 6.6, and 8.7 for smokers exiting movies without smoking, with smoking, horror without smoking and horror with smoking respectively. Smoking in movies was associated with a significantly higher UTS (0.63 [95% CI 0.31-0.94]). Horror with smoking increased UTS by 2.8 points (95% C.I. 2.3, 3.5); the horror without smoking estimate was 0.88, but not statistically significant. This short report offers preliminary evidence that movie horror as one factor besides visual smoking cues that could increase UTS in a community setting.

Prochlorococcus Genetic Transformation and the Genomics of Nitrogen Metabolism

DTIC Science & Technology

2005-09-01

MIT9313 and MED4 have ABC-type urea transporters and urease genes. Prochlorococcus PCC 9511 urease activity is independent of the nitrogen source in the...medium (Palinska et al., 2000), suggesting that the urease genes lack genetic regulation. MIT9313 has genes for nitrite transport and utilization...cyanobacterium, synthesizes the smallest urease ." Microbiology 146 Pt 12: 3099-107. Palinska, K. A., W. Laloui, et al. (2002). "The signal transducer P-Il and

Structure and mechanical characterization of Mg-Nd-Zn alloys prepared by different processes

NASA Astrophysics Data System (ADS)

Dvorský, D.; Kubásek, J.; Vojtěch, D.; Voňavková, I.; Veselý, M.; Čavojský, M.

2017-02-01

Magnesium alloys containing about 3 wt. % of Nd and 0.5 wt. % of Zn are considered as promising materials for application in transport and medical industry. Properly treated materials can reach ultimate tensile strength (UTS) higher than 300 MPa. Also the corrosion resistance of these alloys is superior to many other magnesium-based materials. Present work is focused on the preparation of Mg-3Nd-0.5Zn magnesium alloy by classical casting and subsequent thermal treatment. As-cast material was extruded at 400 °C, with extrusion ratio equal to 16 and velocity of 0.2 mm/s. The effect of thermal treatment and also strong plastic deformation during extrusion on final structure conditions and mechanical properties is specified. Present results confirm significant improvement of tensile yield strength (TYS) and UTS after extrusion process as a consequence of fine-grained structure combined with precipitation strengthening. Beside, texture strengthening in the direction parallel to the extrusion has been observed too.

Effective NiMn Nanoparticles-Functionalized Carbon Felt as an Effective Anode for Direct Urea Fuel Cells.

PubMed

Barakat, Nasser A M; Alajami, Mohannad; Ghouri, Zafar Khan; Al-Meer, Saeed

2018-05-16

The internal resistances of fuel cells strongly affect the generated power. Basically, in the fuel cell, the anode can be prepared by deposition of a film from the functional electrocatalyst on a proper gas diffusion layer. Accordingly, an interfacial resistance for the electron transport is created between the two layers. Electrocatalyst-functionalized gas diffusion layer (GDL) can distinctly reduce the interfacial resistance between the catalyst layer and the GDL. In this study, NiMn nanoparticles-decorated carbon felt is introduced as functionalized GDL to be exploited as a ready-made anode in a direct urea fuel cell. The proposed treated GDL was prepared by calcination of nickel acetate/manganese acetate-loaded carbon felt under an argon atmosphere at 850 °C. The physiochemical characterizations confirmed complete reduction for the utilized precursors and deposition of pristine NiMn nanoparticles on the carbon felt fiber. In passive direct urea fuel cells, investigation the performance of the functionalized GDLs indicated that the composition of the metal nanoparticles has to be optimized as the GDL obtained from 40 wt % manganese acetate reveals the maximum generated power density; 36 mW/m² at room temperature and 0.5 M urea solution. Moreover, the electrochemical measurements proved that low urea solution concentration is preferred as utilizing 0.5 M solution resulted into generating higher power compared to 1.0 and 2.0 M solution. Overall, this study opens a new avenue toward functionalization of the GDL as a novel strategy to overcome the interfacial resistance between the electrocatalyst and the GDL.

Effective NiMn Nanoparticles-Functionalized Carbon Felt as an Effective Anode for Direct Urea Fuel Cells

PubMed Central

Barakat, Nasser A. M.; Alajami, Mohannad; Ghouri, Zafar Khan; Al-Meer, Saeed

2018-01-01

The internal resistances of fuel cells strongly affect the generated power. Basically, in the fuel cell, the anode can be prepared by deposition of a film from the functional electrocatalyst on a proper gas diffusion layer. Accordingly, an interfacial resistance for the electron transport is created between the two layers. Electrocatalyst-functionalized gas diffusion layer (GDL) can distinctly reduce the interfacial resistance between the catalyst layer and the GDL. In this study, NiMn nanoparticles-decorated carbon felt is introduced as functionalized GDL to be exploited as a ready-made anode in a direct urea fuel cell. The proposed treated GDL was prepared by calcination of nickel acetate/manganese acetate-loaded carbon felt under an argon atmosphere at 850 °C. The physiochemical characterizations confirmed complete reduction for the utilized precursors and deposition of pristine NiMn nanoparticles on the carbon felt fiber. In passive direct urea fuel cells, investigation the performance of the functionalized GDLs indicated that the composition of the metal nanoparticles has to be optimized as the GDL obtained from 40 wt % manganese acetate reveals the maximum generated power density; 36 mW/m2 at room temperature and 0.5 M urea solution. Moreover, the electrochemical measurements proved that low urea solution concentration is preferred as utilizing 0.5 M solution resulted into generating higher power compared to 1.0 and 2.0 M solution. Overall, this study opens a new avenue toward functionalization of the GDL as a novel strategy to overcome the interfacial resistance between the electrocatalyst and the GDL. PMID:29772710

Rehabilitation Exercises to Induce Balanced Scapular Muscle Activity in an Anti-gravity Posture

PubMed Central

Ishigaki, Tomonobu; Yamanaka, Masanori; Hirokawa, Motoki; Tai, Keita; Ezawa, Yuya; Samukawa, Mina; Tohyama, Harukazu; Sugawara, Makoto

2014-01-01

[Purpose] The purpose of this study was to compare the intramuscular balance ratios of the upper trapezius muscle (UT) and the lower trapezius muscle (LT), and the intermuscular balance ratios of the UT and the serratus anterior muscle (SA) among prone extension (ProExt), prone horizontal abduction with external rotation (ProHAbd), forward flexion in the side-lying position (SideFlex), side-lying external rotation (SideEr), shoulder flexion with glenohumeral horizontal abduction load (FlexBand), and shoulder flexion with glenohumeral horizontal adduction load (FlexBall) in the standing posture. [Methods] The electromyographic (EMG) activities of the UT, LT and SA were measured during the tasks. The percentage of maximum voluntary isometric contraction (%MVIC) was calculated for each muscle, and the UT/LT ratios and the UT/SA ratios were compared among the tasks. [Results] The UT/LT ratio with the FlexBand was not significantly different from those of the four exercises in the side-lying and prone postures. The UT/SA ratio with the FlexBall demonstrated appropriate balanced activity. [Conclusion] In an anti-gravity posture, we recommend the FlexBand and the FlexBall for inducing balanced UT/LT and UT/SA ratios, respectively. PMID:25540485

Rehabilitation Exercises to Induce Balanced Scapular Muscle Activity in an Anti-gravity Posture.

PubMed

Ishigaki, Tomonobu; Yamanaka, Masanori; Hirokawa, Motoki; Tai, Keita; Ezawa, Yuya; Samukawa, Mina; Tohyama, Harukazu; Sugawara, Makoto

2014-12-01

[Purpose] The purpose of this study was to compare the intramuscular balance ratios of the upper trapezius muscle (UT) and the lower trapezius muscle (LT), and the intermuscular balance ratios of the UT and the serratus anterior muscle (SA) among prone extension (ProExt), prone horizontal abduction with external rotation (ProHAbd), forward flexion in the side-lying position (SideFlex), side-lying external rotation (SideEr), shoulder flexion with glenohumeral horizontal abduction load (FlexBand), and shoulder flexion with glenohumeral horizontal adduction load (FlexBall) in the standing posture. [Methods] The electromyographic (EMG) activities of the UT, LT and SA were measured during the tasks. The percentage of maximum voluntary isometric contraction (%MVIC) was calculated for each muscle, and the UT/LT ratios and the UT/SA ratios were compared among the tasks. [Results] The UT/LT ratio with the FlexBand was not significantly different from those of the four exercises in the side-lying and prone postures. The UT/SA ratio with the FlexBall demonstrated appropriate balanced activity. [Conclusion] In an anti-gravity posture, we recommend the FlexBand and the FlexBall for inducing balanced UT/LT and UT/SA ratios, respectively.

Anomalous toluene transport in model segmented polyurethane-urea/clay nanocomposites.

PubMed

Rath, Sangram K; Bahadur, Jitendra; Panda, Himanshu S; Sen, Debasis; Patro, T Umasankar; S, Praveen; Patri, Manornajan; Khakhar, Devang V

2018-05-16

The kinetics of liquid solvent sorption in polymeric systems and their nanocomposites often deviate from normal Fickian behaviour. This needs to be understood and interpreted, in terms of their underlying mechanistic origins. In the present study, the results of time dependent toluene sorption measurements in model segmented polyurethane-urea/clay nanocomposites have been analysed at room temperature. The studies revealed pronounced S-shaped sorption curves and unusually higher swelling of the nanocomposites compared to the neat polyurethane-urea matrix. Dynamic mechanical analysis (DMA) and small angle X-ray scattering (SAXS) measurements on the nanocomposites in the dry and liquid toluene saturated state have been carried out. The DMA studies revealed a significant decrease in the α relaxation temperature and storage modulus of the nanocomposites in the swollen state compared to the dry samples. The SAXS results showed that the nanoclay dispersion morphology transformed from intercalation in the dry state to exfoliation in the swollen state and the interdomain distance between hard segments increased upon swelling. Thermodynamic analysis of the Flory-Huggins interaction parameter (χ) of nanocomposite/toluene systems revealed increasingly negative χ values with increased clay loading. These results imply a significant plasticization effect of toluene on the nanocomposites. An interpretation of these data, which relates the abovementioned results, is presented in the framework of differential swelling stress (DSS) induced deviation from Fickian transport characteristics. We expect that these findings and methods may provide new insight into the analysis of the solvent diffusion process in heterogeneous polymers and their nanocomposites.

Role of Uremic Toxins for Kidney, Cardiovascular, and Bone Dysfunction.

PubMed

Fujii, Hideki; Goto, Shunsuke; Fukagawa, Masafumi

2018-05-16

With decreasing kidney function, cardiovascular disease (CVD) and mineral bone disorders frequently emerge in patients with chronic kidney disease (CKD). For these patients, in addition to the traditional risk factors, non-traditional CKD-specific risk factors are also associated with such diseases and conditions. One of these non-traditional risk factors is the accumulation of uremic toxins (UTs). In addition, the accumulation of UTs further deteriorates kidney function. Recently, a huge number of UTs have been identified. Although many experimental and clinical studies have reported associations between UTs and the progression of CKD, CVD, and bone disease, these relationships are very complex and have not been fully elucidated. Among the UTs, indoxyl sulfate, asymmetric dimethylarginine, and p -cresylsulfate have been of particular focus, up until now. In this review, we summarize the pathophysiological influences of these UTs on the kidney, cardiovascular system, and bone, and discuss the clinical data regarding the harmful effects of these UTs on diseases and conditions.

The putative endocannabinoid transport blocker LY2183240 is a potent inhibitor of FAAH and several other brain serine hydrolases.

PubMed

Alexander, Jessica P; Cravatt, Benjamin F

2006-08-02

How lipid transmitters move within and between cells to communicate signals remains an important and largely unanswered question. Integral membrane transporters, soluble lipid-binding proteins, and metabolic enzymes have all been proposed to collaboratively regulate lipid signaling dynamics in vivo. Assignment of the relative contributions made by each of these classes of proteins requires selective pharmacological agents to perturb their individual functions. Recently, LY2183240, a heterocyclic urea inhibitor of the putative endocannabinoid (EC) transporter, was shown to disrupt the cellular uptake of the lipid EC anandamide and promote analgesia in vivo. Here, we show that LY2183240 is a potent, covalent inhibitor of the EC-degrading enzyme fatty acid amide hydrolase (FAAH). LY2183240 inactivates FAAH by carbamylation of the enzyme's serine nucleophile. More global screens using activity-based proteomic probes identified several additional serine hydrolases that are also inhibited by LY2183240. These results indicate that the blockade of anandamide uptake observed with LY2183240 may be due primarily to the inactivation of FAAH, providing further evidence that this enzyme serves as a metabolic driving force that promotes the diffusion of anandamide into cells. More generally, the proteome-wide target promiscuity of LY2183240 designates the heterocyclic urea as a chemotype with potentially excessive protein reactivity for drug design.

Rupture utérine sur utérus bicorne à 12 semaines d'aménorrhée: à propos d'un cas

PubMed Central

Itchimouh, Sanaa; Khabtou, Karima; Mahdaoui, Sakher; Boufettal, Houssine; Samouh, Naima

2016-01-01

La fréquence des malformations utérines ayant un impact sur la reproduction est difficile à apprécier. Leur mise en évidence nécessite un bilan spécifique (hystérosalpingographie, hystéroscopie, cœlioscopie). La fertilité spontanée peut être altérée en fonction du type d'anomalie utérine. Toutes ces anomalies peuvent avoir des répercussions sur l’évolution de la conception à type de fausses couches précoces et tardives, de grossesse extra utérine, de menace d'accouchement prématuré, d'accouchement prématuré, de pathologies vasculaires gravidiques et de retard de croissance intra-utérin. L'utérus bicorne est la plus connue des malformations et représente environ la moitié des anomalies de l'utérus. La survenue d'une telle grossesse constitue une situation à risque pouvant entraîner une mort maternelle, mais le diagnostic précoce et un bon suivi peut mener des grossesses à terme sur des utérus malformé. Le dépistage échographique devrait permettre la détection systématique de ce genre de cas afin de prendre préventivement les mesures qui s'imposent. Nous rapportons un cas de rupture utérine sur utérus bicorne unicervical sur grossesse à 12 semaines d'aménorrhée. PMID:27642490

Measurements of HCl and HNO3 with the new research aircraft HALO - Quantification of the stratospheric contribution to the O3 and HNO3 budget in the UT/LS

NASA Astrophysics Data System (ADS)

Jurkat, Tina; Kaufmann, Stefan; Voigt, Christiane; Zahn, Andreas; Schlager, Hans; Engel, Andreas; Bönisch, Harald; Dörnbrack, Andreas

2013-04-01

Dynamic and chemical processes modify the ozone (O3) budget of the upper troposphere/lower stratosphere, leading to locally variable O3 trends. In this region, O3 acts as a strong greenhouse gas with a net positive radiative forcing. It has been suggested, that the correlation of the stratospheric tracer hydrochloric acid (HCl) with O3 can be used to quantify stratospheric O3 in the UT/LS region (Marcy et al., 2004). The question is, whether the stratospheric contribution to the nitric acid (HNO3) budget in the UT/LS can be determined by a similar approach in order to differentiate between tropospheric and stratospheric sources of HNO3. To this end, we performed in situ measurements of HCl and HNO3 with a newly developed Atmospheric chemical Ionization Mass Spectrometer (AIMS) during the TACTS (Transport and Composition in the UTLS) / ESMVal (Earth System Model Validation) mission in August/September 2012. The linear quadrupole mass spectrometer deployed aboard the new German research aircraft HALO was equipped with a new discharge source generating SF5- reagent ions and an in-flight calibration allowing for accurate, spatially highly resolved trace gas measurements. In addition, sulfur dioxide (SO2), nitrous acid (HONO) and chlorine nitrate (ClONO2) have been simultaneously detected with the AIMS instrument. Here, we show trace gas distributions of HCl and HNO3 measured during a North-South transect from Northern Europe to Antarctica (68° N to 65° S) at 8 to 15 km altitude and discuss their latitude dependence. In particular, we investigate the stratospheric ozone contribution to the ozone budget in the mid-latitude UT/LS using correlations of HCl with O3. Differences in these correlations in the subtropical and Polar regions are discussed. A similar approach is used to quantify the HNO3 budget of the UT/LS. We identify unpolluted atmospheric background distributions and various tropospheric HNO3 sources in specific regions. Our observations can be compared to data from remote sensing instruments. Further, they will help to validate global chemistry-climate models to gain a better understanding of the trace gas distribution in the UT/LS. Marcy, T. P., Fahey, D. W., Gao, R. S., Popp, P. J., Richard, E. C., Thompson, T. L., Rosenlof, K. H., Ray, E. A., Salawitch, R. J., Atherton, C. S., Bergmann, D. J., Ridley, B. A., Weinheimer, A. J., Loewenstein, M., Weinstock, E. M., and Mahoney, M. J.: Quantifying stratospheric ozone in the upper troposphere with in situ measurements of HCl, Science, 304, 261-265, 2004.

Stinging Nettle (Urtica dioica L.) Attenuates FFA Induced Ceramide Accumulation in 3T3-L1 Adipocytes in an Adiponectin Dependent Manner.

PubMed

Obanda, Diana N; Zhao, Peng; Richard, Allison J; Ribnicky, David; Cefalu, William T; Stephens, Jacqueline M

2016-01-01

Excess dietary lipids result in the accumulation of lipid metabolites including ceramides that can attenuate insulin signaling. There is evidence that a botanical extract of Urtica dioica L. (stinging nettle) improves insulin action, yet the precise mechanism(s) are not known. Hence, we examined the effects of Urtica dioica L. (UT) on adipocytes. We investigated the effects of an ethanolic extract of UT on free fatty acid (palmitic acid) induced inhibition of insulin-stimulated Akt serine phosphorylation and modulation of ceramidase expression in 3T3-L1 adipocytes. Adipocytes were exposed to excess FFAs in the presence or absence of UT. Effects on adiponectin expression, ceramidase expression, ceramidase activity, ceramide accumulation and insulin signaling were determined. As expected, FFAs reduced adiponectin expression and increased the expression of ceramidase enzymes but not their activity. FFA also induced the accumulation of ceramides and reduced insulin-stimulated phosphorylation of Akt in adipocytes. The effects of FFA were partially reversed by UT. UT enhanced adiponectin expression and ceramidase activity in the presence of excess FFAs. UT abated ceramide accumulation and increased insulin sensitivity via enhanced Akt phosphorylation. A siRNA knockdown of adiponectin expression prevented UT from exerting positive effects on ceramidase activity but not Akt phosphorylation. In adipocytes, the ability of UT to antagonize the negative effects of FFA by modulating ceramidase activity and ceramide accumulation is dependent on the presence of adiponectin. However, the ability of UT to enhance Akt phosphorylation is independent of adiponectin expression. These studies demonstrate direct effects of UT on adipocytes and suggest this botanical extract is metabolically beneficial.

Stinging Nettle (Urtica dioica L.) Attenuates FFA Induced Ceramide Accumulation in 3T3-L1 Adipocytes in an Adiponectin Dependent Manner

PubMed Central

Obanda, Diana N.; Zhao, Peng; Richard, Allison J.; Ribnicky, David; Cefalu, William T.; Stephens, Jacqueline M.

2016-01-01

Objective Excess dietary lipids result in the accumulation of lipid metabolites including ceramides that can attenuate insulin signaling. There is evidence that a botanical extract of Urtica dioica L. (stinging nettle) improves insulin action, yet the precise mechanism(s) are not known. Hence, we examined the effects of Urtica dioica L. (UT) on adipocytes. Research Design We investigated the effects of an ethanolic extract of UT on free fatty acid (palmitic acid) induced inhibition of insulin-stimulated Akt serine phosphorylation and modulation of ceramidase expression in 3T3-L1 adipocytes. Adipocytes were exposed to excess FFAs in the presence or absence of UT. Effects on adiponectin expression, ceramidase expression, ceramidase activity, ceramide accumulation and insulin signaling were determined. Results As expected, FFAs reduced adiponectin expression and increased the expression of ceramidase enzymes but not their activity. FFA also induced the accumulation of ceramides and reduced insulin-stimulated phosphorylation of Akt in adipocytes. The effects of FFA were partially reversed by UT. UT enhanced adiponectin expression and ceramidase activity in the presence of excess FFAs. UT abated ceramide accumulation and increased insulin sensitivity via enhanced Akt phosphorylation. A siRNA knockdown of adiponectin expression prevented UT from exerting positive effects on ceramidase activity but not Akt phosphorylation. Conclusions In adipocytes, the ability of UT to antagonize the negative effects of FFA by modulating ceramidase activity and ceramide accumulation is dependent on the presence of adiponectin. However, the ability of UT to enhance Akt phosphorylation is independent of adiponectin expression. These studies demonstrate direct effects of UT on adipocytes and suggest this botanical extract is metabolically beneficial. PMID:26939068

Using the urtA Gene to Profile Nitrogen Stress Adaptation and Spatio-Temporal Abundance of Synechococcus Clades in the California Current System

NASA Astrophysics Data System (ADS)

Chatterjee, T.; Shilova, I. N.; Zehr, J. P.

2015-12-01

Among the planet's most abundant photosynthetic groups, the picocyanobacteria Synechococcus contributes nearly a quarter of our global oxygen supply. Urea, from both natural and anthropogenic sources, is an important alternative to the preferred yet limited sources of reduced nitrogen for cyanobacteria in the marine environment. While urea uptake activity has been observed during nitrogen (N) limitation, this stress adaptation is not well-studied in natural habitats. We propose the urtAgene, which encodes the substrate-binding subunit of the urea-uptake ABC transporter, as a molecular marker to profile cell abundance and stress response in relation to N fluctuation. Strains prevalent in temperate waters of the California Current System - Synechococcus CC9311 (clade I), CC9605 (clade II) and CC9902/BL107 (clade IV) - were targeted by clade-specific qPCR assays to measure urtA gene copy abundance in samples from different geographical stations and a time-series. Spatial and seasonal patterns in clade abundance resembled those previously reported by studies using other Synechococcus marker genes, thus validating urtA as a strong marker. Synechococcus clades I and IV were most abundant in coastal and transitional stations, while the more oligotrophic clade II was detected near open waters. Synechococcus abundances were highest before and after the annual upwelling season, as supported by a non clade-specific rbcL-qPCR assay. A lack of correlation between abundance and nitrate availability indicated utilization of alternative nitrogen sources like urea, which was further evidenced by the detection of clade IV urtA transcripts at the station closest to shore. Urea concentrations tend to be highest in coastal environments due to fertilizer runoff, which can stimulate phytoplankton blooms including harmful algal blooms. This study adds to insight on how such environmental factors are related to N-cycling and patterns of urea-assimilating microbial populations like Synechococcus subgroups in the California Current waters of the Pacific Ocean.

Edwardsiella ictaluri Encodes an Acid-Activated Urease That Is Required for Intracellular Replication in Channel Catfish (Ictalurus punctatus) Macrophages▿

PubMed Central

Booth, Natha J.; Beekman, Judith B.; Thune, Ronald L.

2009-01-01

Genomic analysis indicated that Edwardsiella ictaluri encodes a putative urease pathogenicity island containing the products of nine open reading frames, including urea and ammonium transporters. In vitro studies with wild-type E. ictaluri and a ureG::kan urease mutant strain indicated that E. ictaluri is significantly tolerant of acid conditions (pH 3.0) but that urease activity is not required for acid tolerance. Growth studies demonstrated that E. ictaluri is unable to grow at pH 5 in the absence of urea but is able to elevate the environmental pH from pH 5 to pH 7 and grow when exogenous urea is available. Substantial production of ammonia was observed for wild-type E. ictaluri in vitro in the presence of urea at low pH, and optimal activity occurred at pH 2 to 3. No ammonia production was detected for the urease mutant. Proteomic analysis with two-dimensional gel electrophoresis indicated that urease proteins are expressed at both pH 5 and pH 7, although urease activity is detectable only at pH 5. Urease was not required for initial invasion of catfish but was required for subsequent proliferation and virulence. Urease was not required for initial uptake or survival in head kidney-derived macrophages but was required for intracellular replication. Intracellular replication of wild-type E. ictaluri was significantly enhanced when urea was present, indicating that urease plays an important role in intracellular survival and replication, possibly through neutralization of the acidic environment of the phagosome. PMID:19749068

Elevated urinary urea by high-protein diet could be one of the inducements of bladder disorders.

PubMed

Liu, Ming; Li, Min; Liu, Jiangfeng; Wang, Hongkai; Zhong, Dandan; Zhou, Hong; Yang, Baoxue

2016-02-16

Previous work found that urea accumulation in urothelial cells caused by urea transporter B knockout led to DNA damage and apoptosis that contributed to the carcinogenesis. The purpose of this study is to explore the potential connection between high urinary urea concentration and the bladder disorders. A high protein diet rat model was conducted by feeding with 40 % protein diet. In-silico modeling and algorithm, based on the results of microarray and proteomics from the bladder urothelium, were used for the reconstruction of accurate cellular networks and the identification of novel master regulators in the high-protein diet rat model. Pathway and biological process enrichment analysis were used to characterize predicted targets of candidate mRNAs/proteins. The expression pattern of the most significant master regulators was evaluated by qPCR and immunohistochemistry. Based on the analysis of different expressed mRNAs/proteins, 15 significant ones (CRP, MCPT2, MCPT9, EPXH2, SERPING1, SRGN, CDKN1C, CDK6, CCNB1, PCNA, BAX, MAGEB16, SERPINE1, HSPA2, FOS) were highly identified and verified by qPCR and immunohistochemistry. They were involved in immune and inflammatory response, cell cycle arrest, apoptosis and pathways in cancer. These abnormally activated processes caused the bladder interstitial congestion and inflammatory infiltrates under the thinner urothelium, cell desquamation, cytoplasm vacuolization, nucleus swelling and malformation in the high-protein diet group. We provided evidences that high urinary urea concentration caused by high-protein diet might be a potential carcinogenic factor in bladder.

Upregulation of erythropoietin receptor in UT-7/EPO cells inhibits simulated microgravity-induced cell apoptosis

NASA Astrophysics Data System (ADS)

Zou, Li-xue; Cui, Shao-yan; Zhong, Jian; Yi, Zong-chun; Sun, Yan; Fan, Yu-bo; Zhuang, Feng-yuan

2011-07-01

Hematopoietic progenitor cell proliferation can be altered in either spaceflight or under simulated microgravity experiments on the ground, however, the underlying mechanism remains unknown. Our previous study showed that exposure of the human erythropoietin (EPO)-dependent leukemia cell line UT-7/EPO to conditions of simulated microgravity significantly inhibited the cellular proliferation rate and induced cell apoptosis. We postulated that the downregulation of the erythropoietin receptor (EPOR) expression in UT-7/EPO cells under simulated microgravity may be a possible reason for microgravity triggered apoptosis. In this paper, a human EPOR gene was transferred into UT-7/EPO cells and the resulting expression of EPOR on the surface of UT-7/EPO cells increased approximately 61% ( p < 0.05) as selected by the antibiotic G418. It was also shown through cytometry assays and morphological observations that microgravity-induced apoptosis markedly decreased in these UT-7/EPO-EPOR cells. Thus, we concluded that upregulation of EPOR in UT-7/EPO cells could inhibit the simulated microgravity-induced cell apoptosis in this EPO dependent cell line.

Taking the Pulse of PyroCumulus Clouds

NASA Technical Reports Server (NTRS)

Gatebe, C. K.; Varnai, T.; Poudyal, R.; Ichoku, C.; King, M. D.

2012-01-01

Forest fires can burn large areas, but can also inject smoke into the upper troposphere/lower stratosphere (UT/LS), where stakes are even higher for climate, because emissions tend to have a longer lifetime, and can produce significant regional and even global climate effects, as is the case with some volcanoes. Large forest fires are now believed to be more common in summer, especially in the boreal regions, where pyrocumulus (pyroCu), and occasionally pyrocumuionimbus (pyroCb) clouds are formed, which can transport emissions into the UT/LS. A major difficulty in developing realistic fire plume models is the lack of observational data within fire plumes that resolves structure at a few 100 m scales, which can be used to validate these models. Here, we report detailed airborne radiation measurements within strong pyroCu taken over boreal forest fires in Saskatchewan, Canada during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) summer field campaign in 2008. We find that the angular distribution of radiance within the pyroCu is closely related to the diffusion domain in water clouds and can be described by very similar simple cosine functions. We demonstrate with Monte Carlo simulations that radiation transport in pyroCu is inherently a 3D phenomenon and must account for particle absorption. However, the simple cosine function promises to offer an easy solution for climate models. The presence of a prominent smoke core, defined by strong extinction in the UV, VIS and NIR, suggests that the core might be an important pathway for emission transport to the upper troposphere and lower stratosphere. We speculate that this plume injection core is generated and sustained by complex processes not yet well understood, but not necessarily related directly to the intense fires that originally initiated the plume rise.

Edwardsiella ictaluri Encodes an Acid Activated Urease that is Required for Intracellular Replication in Channel Catfish Ictalurus punctatus Macrophages

USDA-ARS?s Scientific Manuscript database

Genomic analysis indicated that Edwardsiella ictaluri encodes a putative ureasepathogenicity island containing 9 open reading frames, including urea and ammonium transporters. In vitro studies with the wild-type E. ictaluri and a ureG::kan urease mutant strain indicated that E. ictaluri is significa...

78 FR 45473 - Proposed Amendment of Class E Airspace; St. George, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-29

...-0600; Airspace Docket No. 13-ANM-18 Proposed Amendment of Class E Airspace; St. George, UT AGENCY... action proposes to amend Class E airspace at St. George Municipal Airport, St. George, UT, by removing... aircraft operations at St. George Municipal Airport, St. George, UT. DATES: Comments must be received on or...

76 FR 2800 - Establishment of Class E Airspace; Lucin, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-18

...-2010-1208; Airspace Docket No. 10-ANM-16] Establishment of Class E Airspace; Lucin, UT AGENCY: Federal... E en route domestic airspace for the Lucin VORTAC, Lucin, UT. DATES: Effective 0901 UTC, February 17..., UT, incorrectly referenced the existing Class E en route domestic airspace exclusion above 8,500 feet...

Seasonal cycles of atmospheric methane and its carbon and hydrogen isotopic ratios in the lower and upper troposphere of the western Pacific region

NASA Astrophysics Data System (ADS)

Umezawa, T.; Aoki, S.; Nakazawa, T.; Machida, T.; Matsueda, H.; Sawa, Y.; Ishijima, K.; Patra, P. K.

2009-12-01

Although carbon and hydrogen isotopic ratios (δ13C and δD) of CH4 provide useful information about its sources and sinks, systematic measurements were quite limited. Tohoku University group and NIES group have conducted air-sampling programs by using commercial container ships sailing between Japan and New Zealand and by using commercial airliners flying between Australia and Japan, respectively. Using air samples collected by the programs, systematic measurements of δ13C and δD of atmospheric CH4 as well as CH4 concentration ([CH4]) have been made since 2006. Here, we report their spatial and temporal variations in the lower and upper troposphere (LT and UT). In the LT of the northern hemisphere (NH), the seasonal cycle of [CH4] showed the maximum in winter and the minimum in summer. δ13C varied seasonally almost negatively correlating with the [CH4], and the seasonality of δD showed much more significant negative correlation with the [CH4]. It was also found that CH4 sources with seasonally varying strength, such as wetlands with high emissions in late summer, play an important role in the atmospheric CH4 variations. In the tropics, a seasonally-dependent air exchange between the NH and the southern hemisphere (SH) was found to characterize the seasonal CH4 cycle. When the NH and SH air arrived, high and low [CH4] were observed, accompanied by low and high δ13C and δD values, respectively. In the LT of the SH, the seasonal maximum and minimum of the [CH4] appeared in austral winter and summer, respectively. The seasonal CH4 cycle was mainly ascribed to the seasonality in the CH4+OH reaction, but δ13C and δD showed rather complicated seasonality with larger amplitudes than expected from the CH4+OH reaction alone, suggesting additional contribution of a CH4+Cl reaction in the marine boundary layer. In the UT of the NH, the seasonal maximum and minimum of the [CH4] appeared in summer and winter-spring, respectively, with low and high values of δ13C and δD in corresponding seasons. The summertime high [CH4] was observed when the [CH4] showed the seasonal minimum in the LT. By examining the relationship between δ13C (or δD) and the [CH4], as well as the results of tagged tracer experiments using the CCSR/NIES/FRCGC AGCM-based chemical transport model, we found that biogenic CH4 emissions from India, Southeast Asia and China are responsible for such summertime high [CH4] in the UT. By comparing the latitudinal distributions of the annual average [CH4], δ13C and δD in the UT and LT, we found that [CH4] and δD in the NH were higher and lower in the LT than in the UT, respectively, while the situation was opposite in the SH, due to NH air intrusion through the UT. On the other hand, δ13C showed no different distributions in the LT and UT of the NH, while δ13C in the SH was higher in the LT than in the UT, probably due to the contribution of the CH4+Cl reaction in the marine boundary layer.

Neurological implications of urea cycle disorders

PubMed Central

Summar, M.; Leonard, J. V.

2013-01-01

Summary The urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular 1H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate–nitric oxide–cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia-lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders. PMID:18038189

The Astronomical Almanac Online - Glossary

Science.gov Websites

Astronomical Almanac. Δ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z $\\boldmath{\\Delta {\\rm T}}$: the difference between Terrestrial Time (TT) and Universal Time (UT): $\\Delta {\\rm T} = {\\rm TT} - {\\rm UT}1 $. $\\boldmath{\\Delta {\\rm UT1}}$ (or $\\boldmath{\\Delta {\\rm UT}}$): the value of the difference between

Regions of conservation and divergence in the 3' untranslated sequences of genomic RNA from Ross River virus isolates.

PubMed

Faragher, S G; Dalgarno, L

1986-07-20

The 3' untranslated (UT) sequences of the genomic RNAs of five geographic variants of the alphavirus Ross River virus (RRV) were determined and compared with the 3' UT sequence of RRV T48, the prototype strain. Part of the 3' UT region of Getah virus, a close serological relative of RRV, was also sequenced. The RRV 3' UT region varies markedly in length between variants. Large deletions or insertions, sequence rearrangements and single nucleotide substitutions are observed. A sequence tract of 49 to 58 nucleotides, which is repeated as four blocks in the RRV T48 3' UT region, occurs only once in the 3' UT region of one RRV strain (NB5092), indicating that the existence of repeat sequence blocks is not essential for RRV replication. However, the precise sequence of the 3' proximal copy of the repeat block and its position relative to the poly(A) tail were identical in all RRV isolates examined, suggesting that it has an important role in RRV replication. Nucleotide substitutions between RRV variants are distributed non-randomly along the length of the 3' UT region. The sequence of 120 to 130 nucleotides adjacent to the poly(A) tail is strongly conserved. Getah virus RNA contains three repeat sequence blocks in the 3' UT region. These are similar in sequence to those in RRV RNA but differ in their arrangement. Homology between the RRV and Getah 3' UT sequences is greatest in the 3' proximal repeat sequence block that shows three differences in 49 nucleotides. The 3' proximal repeat in Getah RNA occurs at the same position, relative to the poly(A) tail, as in all RRV variants. The RRV and Getah virus 3' UT sequences show extensive homology in the region between the 3' proximal repeat and the poly(A) tail but, apart from the repeat blocks themselves, they show no significant homology elsewhere.

Maximum urine concentrating capability in a mathematical model of the inner medulla of the rat kidney.

PubMed

Marcano, Mariano; Layton, Anita T; Layton, Harold E

2010-02-01

In a mathematical model of the urine concentrating mechanism of the inner medulla of the rat kidney, a nonlinear optimization technique was used to estimate parameter sets that maximize the urine-to-plasma osmolality ratio (U/P) while maintaining the urine flow rate within a plausible physiologic range. The model, which used a central core formulation, represented loops of Henle turning at all levels of the inner medulla and a composite collecting duct (CD). The parameters varied were: water flow and urea concentration in tubular fluid entering the descending thin limbs and the composite CD at the outer-inner medullary boundary; scaling factors for the number of loops of Henle and CDs as a function of medullary depth; location and increase rate of the urea permeability profile along the CD; and a scaling factor for the maximum rate of NaCl transport from the CD. The optimization algorithm sought to maximize a quantity E that equaled U/P minus a penalty function for insufficient urine flow. Maxima of E were sought by changing parameter values in the direction in parameter space in which E increased. The algorithm attained a maximum E that increased urine osmolality and inner medullary concentrating capability by 37.5% and 80.2%, respectively, above base-case values; the corresponding urine flow rate and the concentrations of NaCl and urea were all within or near reported experimental ranges. Our results predict that urine osmolality is particularly sensitive to three parameters: the urea concentration in tubular fluid entering the CD at the outer-inner medullary boundary, the location and increase rate of the urea permeability profile along the CD, and the rate of decrease of the CD population (and thus of CD surface area) along the cortico-medullary axis.

A study on the migration and transformation law of nitrogen in urine in municipal wastewater transportation and treatment.

PubMed

Wuang, Ren; Pengkang, Jin; Chenggang, Liang; Xiaochang, Wang; Lei, Zhang

2013-01-01

Many studies suggest that the total nitrogen (TN) in urine is around 9,000 mg/L and about 80% of nitrogen in municipal wastewater comes from urine, because nitrogen mainly occurs in the form of urea in fresh human urine. Based on this fact, the study on the migration and transformation law of nitrogen in urine and its influencing factors was carried out. It can be seen from the experimental results that the transformation rate of urea in urine into ammonia nitrogen after standing for 20 days is only about 18.2%, but the urea in urine can be hydrolyzed into ammonia nitrogen rapidly after it is catalyzed directly with free urease or indirectly with microorganism. Adding respectively a certain amount of urease, activated sludge and septic-tank sludge to urine samples can make the maximum transformation rate achieve 85% after 1 day, 2 days and 6 days, respectively. In combination with some corresponding treatment methods, recycling of nitrogen in urine can be achieved. The results are of great significance in guiding denitrification in municipal wastewater treatment.

Tunable Far Infrared Semiconductor Sources.

DTIC Science & Technology

1984-01-01

plasmons in Si-MOS4 hot electron transport in Si-MOS-devices a , ABSTR ACT (Coathwe st e verse 8641 It ut’.weemY dmd ideti ty by block tnmber) {fhe...After baking at 900C for 20 minutes the photoresist was -17- exposed for 8 seconds on the SUss-MJB3-contact lithography machine. To obtain grating...could fabricate Al gratings with 1.5 am - periods on Si-MOSFETs and GaAs-samples by optical contact lithography and lift-off metallization. Fig. 8 shows

Evaluating Corrosion in SAVY Containers using Non-Destructive Techniques

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

Davenport, Matthew Nicholas; Vaidya, Rajendra U.; Abeyta, Adrian Anthony

Powerpoint presentation on Ultrasonic and Eddy Current NDT; UT Theory; Eddy current (ECA): How it works; Controlled Corrosion at NM Tech; Results – HCl Corrosion; Waveform Data for 10M HCl; Accuracy Statistics; Results – FeCl 3 Pitting; Waveforms for Anhydrous FeCl 3; Analyzing Corroded Stainless Steel 316L Plates; 316L Plate to Imitate Pitting; ECA Pit Depth Calibration Curve; C Scan Imaging; UT Pit Detection; SST Containers: Ultrasonic (UT) vs. CMM; UT Data Analysis; UT Conclusions and Observations; ECA Conclusions; Automated System Vision.

Impact of aerobic and anaerobic exercise training on oxidative stress and antioxidant defense in athletes.

PubMed

Park, Song-Young; Kwak, Yi-Sub

2016-04-01

Exercise mediates an excessive free radical production leading to oxidative stress (OS). The body has natural antioxidant systems that help decrease OS, and these systems may be enhanced with exercise training. However, only a few studies have investigated the differences in resting OS and antioxidant capacity (AOC) between aerobically trained athletes (ET), anaerobically trained athletes (RT), and untrained individuals (UT). Therefore, this study sought to investigate the resting and postexercise OS and AOC in ET, RT, and UT. Sixty healthy young males (26.6±0.8 yr) participated in this study. Subjects were divided into three groups, ET, RT, and UT by distinct training background. Resting plasma malondialdehyde (MDA) and protein carbonyls (PC) were not significantly different in ET, RT, and UT. However, MDA and PC were significantly increased following a graded exercise test (GXT) in UT but not in ET and RT. Resting total antioxidant capacity (TAC) levels and TAC were not different in ET, RT, and UT. Interestingly, TAC levels significantly decreased after the GXT in all groups. Additionally, UT showed lower post-exercise TAC levels compared to ET and RT. These results showed that ET, RT, and UT have similar OS and AOC at rest. However, both ET and RT have greater AOC against exercise mediated OS compared to UT. These findings may explain, at least in part, why both aerobic and anaerobic types of exercise training improve redox balance. However, it appears there is no specific exercise type effect in terms of redox balance.

Near real-time monitoring of UT1 with geodetic VLBI

NASA Astrophysics Data System (ADS)

Haas, R.; Hobiger, T.; Sekido, M.; Koyama, Y.; Kondo, T.; Takiguchi, H.; Kurihara, S.; Kokado, K.; Tanimoto, D.; Nozawa, K.; Wagner, J.; Ritakari, J.; Mujunen, A.; Uunila, M.

2011-07-01

Geodetic VLBI is unique among the geodetic space techniques since it provides a direct connection between the international terrestrial reference frame and the international celestial reference frame. The Earth rotation angle, usually expressed as UT1, can be determined directly from geodetic VLBI observations. Accurate information about the Earth rotation angle is necessary and important for navigation purposes, in particular for satellite missions and space navigation. A near real-time knowledge of UT1 with high accuracy is therefore highly desirable. During the last few years the advances in data transfer over high-speed optical fibre lines have made it possible to electronically send the observational data from a VLBI radio telescope on one side of the globe in real-time to a VLBI correlator on the other side of the globe. Thus, data of two telescopes on opposite sides of the Earth, forming a long east-west oriented baseline, can be correlated in near real-time. Furthermore, advances in automated processing of the correlation results have made it possible to derive the Earth rotation angle UT1 in near real-time. Since 2007, the VLBI research groups in Sweden, Finland and Japan collaborate to derive UT1 in near real-time. Several dedicated so-called ultra-rapid UT1-sessions with 1-2 hours duration were performed. It was shown that final UT1-results can be derived within a few minutes after the end of an observing session (Sekido et al., 2008; Matsuzaka et al., 2008). The quality of the UT1-results is on the same level as the so-called IERS rapid solutions, but with a much lower latency (Haas et al., 2010). Recently, the ultra-rapid approach has been applied to standard 24 hour long VLBI observing sessions that are organized by the International VLBI Service for Geodesy and Astrometry (IVS). The long east-west baseline between Onsala (Sweden) and Tsukuba (Japan) is used to derive UT1 with a sliding window approach already during the ongoing IVS-session. The data processing and analysis is performed with a fully automated analysis software (Hobiger et al., 2010). We present results from the ultra-rapid UT1-sessions, both, from dedicated one-baseline sessions, as well from 24-hour ultra-rapid sessions during standard IVS-experiments. The near real-time UT1 results are compared to corresponding post-processing results, and results from independent analyses and techniques. Refrences: Sekido et al. (2008) Ultra-rapid UT1 measurements by e-VLBI, Earth Planets and Space, Vol. 60, 865-870. Matsuzaka et al. (2008) Ultra Rapid UT1 Experiment with e-VLBI, In: Proc. 5th IVS General Meeting, 68-71. Haas R et al. (2010) Ultra-Rapid DUT1-Observations with E-VLBI. Artificial Satellites, 45, 75-79. Hobiger et al. (2010) Fully automated VLBI analysis with c5++ for ultra-rapid determination of UT1, Earth Planets Space.

Magnetic Field Enhancement of Heat Transport in the 2D Heisenberg Antiferromagnet K_2V_3O_8

NASA Astrophysics Data System (ADS)

Sales, B. C.; Lumsden, M. D.; Nagler, S. E.; Mandrus, D.; Jin, R.

2002-03-01

The thermal conductivity and heat capacity of single crystals of the spin 1/2 quasi-2D Heisenberg antiferromagnet K_2V_3O8 have been measured from 1.9 to 300 K in magnetic fields from 0 to 8T. The data are consistent with resonant scattering of phonons by magnons near the zone boundary and heat transport by long wavelength magnons. The magnon heat transport only occurs after the small anisotropic gap at k=0 is closed by the application of a magnetic field. The low temperature thermal conductivity increases linearly with magnetic field after the gap has been closed. Oak Ridge National Laboratory is managed by UT-Battelle LLC for the U.S. Department of Energy under Contract No. DE-AC05-00R22725.

Metagenomic Analysis Revealed Methylamine and Ureide Utilization of Soybean-Associated Methylobacterium

PubMed Central

Minami, Tomoyuki; Anda, Misue; Mitsui, Hisayuki; Sugawara, Masayuki; Kaneko, Takakazu; Sato, Shusei; Ikeda, Seishi; Okubo, Takashi; Tsurumaru, Hirohito; Minamisawa, Kiwamu

2016-01-01

Methylobacterium inhabits the phyllosphere of a large number of plants. We herein report the results of comparative metagenome analyses on methylobacterial communities of soybean plants grown in an experimental field in Tohoku University (Kashimadai, Miyagi, Japan). Methylobacterium was identified as the most dominant genus (33%) among bacteria inhabiting soybean stems. We classified plant-derived Methylobacterium species into Groups I, II, and III based on 16S rRNA gene sequences, and found that Group I members (phylogenetically close to M. extorquens) were dominant in soybean-associated Methylobacterium. By comparing 29 genomes, we found that all Group I members possessed a complete set of genes for the N-methylglutamate pathway for methylamine utilization, and genes for urea degradation (urea carboxylase, urea amidolyase, and conventional urease). Only Group I members and soybean methylobacterial isolates grew in a culture supplemented with methylamine as the sole carbon source. They utilized urea or allantoin (a urea-related compound in legumes) as the sole nitrogen source; however, group III also utilized these compounds. The utilization of allantoin may be crucial in soybean-bacterial interactions because allantoin is a transported form of fixed nitrogen in legume plants. Soybean-derived Group I strain AMS5 colonized the model legume Lotus japonicus well. A comparison among the 29 genomes of plant-derived and other strains suggested that several candidate genes are involved in plant colonization such as csgG (curli fimbriae). Genes for the N-methylglutamate pathway and curli fimbriae were more abundant in soybean microbiomes than in rice microbiomes in the field. Based on these results, we discuss the lifestyle of Methylobacterium in the legume phyllosphere. PMID:27431374

High salt intake reprioritizes osmolyte and energy metabolism for body fluid conservation.

PubMed

Kitada, Kento; Daub, Steffen; Zhang, Yahua; Klein, Janet D; Nakano, Daisuke; Pedchenko, Tetyana; Lantier, Louise; LaRocque, Lauren M; Marton, Adriana; Neubert, Patrick; Schröder, Agnes; Rakova, Natalia; Jantsch, Jonathan; Dikalova, Anna E; Dikalov, Sergey I; Harrison, David G; Müller, Dominik N; Nishiyama, Akira; Rauh, Manfred; Harris, Raymond C; Luft, Friedrich C; Wassermann, David H; Sands, Jeff M; Titze, Jens

2017-05-01

Natriuretic regulation of extracellular fluid volume homeostasis includes suppression of the renin-angiotensin-aldosterone system, pressure natriuresis, and reduced renal nerve activity, actions that concomitantly increase urinary Na+ excretion and lead to increased urine volume. The resulting natriuresis-driven diuretic water loss is assumed to control the extracellular volume. Here, we have demonstrated that urine concentration, and therefore regulation of water conservation, is an important control system for urine formation and extracellular volume homeostasis in mice and humans across various levels of salt intake. We observed that the renal concentration mechanism couples natriuresis with correspondent renal water reabsorption, limits natriuretic osmotic diuresis, and results in concurrent extracellular volume conservation and concentration of salt excreted into urine. This water-conserving mechanism of dietary salt excretion relies on urea transporter-driven urea recycling by the kidneys and on urea production by liver and skeletal muscle. The energy-intense nature of hepatic and extrahepatic urea osmolyte production for renal water conservation requires reprioritization of energy and substrate metabolism in liver and skeletal muscle, resulting in hepatic ketogenesis and glucocorticoid-driven muscle catabolism, which are prevented by increasing food intake. This natriuretic-ureotelic, water-conserving principle relies on metabolism-driven extracellular volume control and is regulated by concerted liver, muscle, and renal actions.

Evidence that one is more likely to see the aurora near Moscow than near Ann Arbor

NASA Astrophysics Data System (ADS)

Liemohn, Michael; Immel, Thomas; Katus, Roxanne

We present a superposed epoch analysis of solar wind drivers and geomagnetic index responses during magnetic storms, categorized as a function of universal time (UT) of the storm peak, to investigate the dependency of storm intensity on UT. Storms with Dst minimum less than - 100 nT were identified in the 1970 - 2012 era (totaling 310 events), covering four solar cycles. The storms were classified into 6 groups based on the UT of the minimum Dst (36 to 82 events per bin), then each grouping was superposed on a timeline that aligns the time of the minimum Dst. Fifteen different quantities were considered, seven solar wind parameters and eight activity indices derived from ground-based magnetometers. Statistical analyses of the superposed means against each other (between the different UT groupings) were conducted to determine the mathematical significance of similarities and differences in the time series plots. It was found that most of the solar wind parameters have essentially no significant difference between the UT groupings, as expected. The exception is solar wind velocity, which appears to be bifurcated into two levels with three of the UT groupings systematically faster than the other three (although, interestingly, not three consecutive UT bins). The geomagnetic activity indices, however, all show statistically significant differences with UT during the main phase and/or early recovery phase. Specifically, the 16, 20, and 00 UT groupings are stronger storms than those in the other UT bins. That is, storms are stronger when the Asian sector is on the nightside (American sector on the dayside) during the main phase. An inference from these findings, therefore, is that one is more likely to see the aurora near Moscow in Russia than near Ann Arbor, Michigan in the United States, even though these two cities have very similar magnetic latitudes (52 degrees).

Implementation of straight and curved steel girder erection design tools construction : summary.

DOT National Transportation Integrated Search

2010-11-05

Project 0-5574 Curved Plate Girder Design for Safe and Economical Construction, resulted in the : development of two design tools, UT Lift and UT Bridge. UT Lift is a spreadsheet-based program for analyzing : steel girders during lifting while ...

Clinical utility of third-trimester uterine artery Doppler in the prediction of brain hemodynamic deterioration and adverse perinatal outcome in small-for-gestational-age fetuses.

PubMed

Cruz-Martinez, R; Savchev, S; Cruz-Lemini, M; Mendez, A; Gratacos, E; Figueras, F

2015-03-01

To assess the clinical value of third-trimester uterine artery (UtA) Doppler ultrasound in the prediction of hemodynamic deterioration and adverse perinatal outcome in term small-for-gestational-age (SGA) fetuses. UtA Doppler parameters, cerebroplacental ratio (CPR) and fetal middle cerebral artery (MCA) pulsatility index (PI) were evaluated weekly, starting from the time of SGA diagnosis until 24 h before induction of labor, in a cohort of 327 SGA fetuses with normal umbilical artery PI (< 95th centile), delivered at > 37 weeks' gestation. Differences in the sequence of CPR and MCA-PI changes < 5th centile, between the group with normal UtA Doppler indices at diagnosis and those with abnormal UtA indices, were analyzed by survival analysis. In addition, the use of UtA Doppler value, alone or in combination with a brain Doppler scan before delivery, to predict the risk of Cesarean section, Cesarean section for non-reassuring fetal status (NRFS), neonatal acidosis and neonatal hospitalization was evaluated by logistic regression analysis, adjusted for gestational age at birth and birth-weight percentile. Abnormal UtA Doppler at diagnosis of SGA was associated with a higher risk of developing abnormal brain Doppler indices before induction of labor than in those with a normal UtA at diagnosis (62.7% vs 34.6%, respectively; P < 0.01). Compared to those with normal UtA Doppler indices, those with abnormal UtA Doppler findings were associated with a higher risk of intrapartum Cesarean section (52.2% vs 37.3%, respectively; P = 0.03), Cesarean section for NRFS (35.8% vs 23.1%, respectively; P = 0.03), neonatal acidosis (10.4% vs 7.7%, respectively; P = 0.47) and neonatal hospitalization (23.9% vs 16.5%, respectively; P = 0.16). Logistic regression analysis indicated that UtA Doppler findings were not significantly associated with adverse perinatal outcome independent of brain Doppler findings. UtA Doppler indices predict adverse perinatal outcome, but do not help to improve the predictive value of brain Doppler indices. However, at the time of SGA diagnosis they identify the subgroup of fetuses at highest risk of progression to abnormal brain Doppler findings. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Usability Tests in Medicine: A Cost-Benefit Analysis for Hospitals Before Acquiring Medical Devices for Theatre.

PubMed

Gonser, Phillipp; Fuchsberger, Thomas; Matern, Ulrich

2017-08-01

The use of active medical devices in clinical routine should be as safe and efficient as possible. Usability tests (UTs) help improve these aspects of medical devices during their development, but UTs can be of use for hospitals even after a product has been launched. The present pilot study examines the costs and possible benefits of UT for hospitals before buying new medical devices for theatre. Two active medical devices with different complexity were tested in a standardized UT and a cost-benefit analysis was carried out assuming a different device bought at the same price with a higher usability could increase the efficiency of task solving and due to that save valuable theatre time. The cost of the UT amounted up to €19.400. Hospitals could benefit from UTs before buying new devices for theatre by reducing time-consuming operator errors and thereby increase productivity and patient safety. The possible benefits amounted from €23.300 to €1.570.000 (median = €797.000). Not only hospitals could benefit economically from investing in a UT before deciding to buy a medical device, but especially patients would profit from a higher usability by reducing possible operator errors and increase safety and performance of use.

A Study of the Broadband Parametric Acoustic Array

DTIC Science & Technology

1982-01-04

iJ~ exp[~~) fj 2 0 . (3.8) This expression indicates a maximum when f =--n (3.9) This result was derived by Findeisen . 64 Using the definitions of n...Interactions of Progressive Finite Amplitude Waves in Nondispersive Fluids," J. Acoust. Soc. Am. 50, 1299-1312 (1971). 64. A. G. Findeisen and S. A. Means, "A...Clynch, ARL:UT 126 George P. Coble, ARL:UT 127 Bernie R. Criswell, ARL:IJT 128 Charles R. Culbertson, ARL:UT 129 Allen G. Findeisen , ARL:UT 130 Karl C

Isometric muscle activation of the serratus anterior and trapezius muscles varies by arm position: a pilot study with healthy volunteers with implications for rehabilitation.

PubMed

Miyasaka, Junsuke; Arai, Ryuzo; Ito, Taisuke; Shingu, Nobuyuki; Hasegawa, Satoshi; Ibuki, Satoko; Ichihashi, Noriaki; Matsuda, Shuichi; Moritani, Toshio

2017-07-01

This study aimed to determine the most appropriate angle and moving direction of the arm for improving coordination of the periscapular muscles, including the serratus anterior (SA), upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT). Muscle activation amplitudes were evaluated in the SA, UT, MT, and LT in 11 healthy subjects by use of surface electromyography. The subjects were asked to maintain the arm position at 5 elevated positions with maximal effort against applied manual forces, which were directed from upper to lower (test 1), lower to upper (test 2), posterior to anterior in the frontal plane and lateral to medial in the sagittal plane (test 3), and anterior to posterior in the frontal plane and medial to lateral in the sagittal plane (test 4). The relative activity of the UT with respect to the SA, MT, and LT was calculated, resulting in the UT/SA, UT/MT, and UT/LT ratios. Test 4 in all positions but 150° of elevation in the frontal plane showed high activity of the SA with a low UT/SA ratio. High MT activity with a low UT/MT ratio was observed during test 3 at the 90° elevated position, whereas high LT activity without UT hyperactivation was not found. To strengthen the periscapular muscles in the balanced condition, horizontal adduction is recommended for the SA. Horizontal abduction at the 90° elevated position should be effective for the MT. Because no technique in this study was effective for the LT, further studies are needed. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Transcranial direct current stimulation versus user training on improving online myoelectric control for amputees

NASA Astrophysics Data System (ADS)

Pan, Lizhi; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Zhu, Xiangyang

2017-08-01

Objective. Transcranial direct current stimulation (tDCS) and user training (UT) are two types of methods to improve myoelectric control performance for amputees. In this study, we compared the independent effect between tDCS and UT, and investigated the combined effect of tDCS and UT. Approach. An online paradigm of simultaneous and proportional control (SPC) based on electromyography (EMG) was adopted. The proposed experiments were conducted on six naïve unilateral trans-radial amputees. The subjects each received three types of 20 min interventions: active tDCS with motor training (tDCS  +  UT), active tDCS with quiet sitting (tDCS), and sham tDCS with motor training (UT). The interventions were applied at one week intervals in a randomized order. The subjects performed online control of a feedback arrow with two degrees of freedom (DoFs) to accomplish target reaching motor tasks in pre-sessions and post-sessions. We compared the performance, measured by completion rate, completion time, and efficiency coefficient, between pre-sessions and post-sessions. Main results. The results showed that the intervention tDCS  +  UT and tDCS significantly improved the online SPC performance (i.e. improved the completion rate; reduced the completion time; and improved the efficiency coefficient), while intervention UT did not significantly change the performance. The results also showed that the online SPC performance after intervention tDCS  +  UT and tDCS was not significantly different, but both were significantly better than that after intervention UT. Significance. tDCS could be an effective intervention to improve the online SPC performance in a short time.

Tropical upper troposphere and tropopause layer in situ measurement of H2O by the micro- SDLA balloon borne diode laser spectrometer: modelling interpretation.

NASA Astrophysics Data System (ADS)

Durry, G.; Huret, N.; Freitas, S.; Hauchecorne, A.; Longo, K.

2006-12-01

During the HIBISCUS European campaign in Bauru (Brazil, 22°S) in 2004, the micro-SDLA diode laser sensor was flown twice on February the 13th (SF2 flight) and the 24th (SF4 flight) from small size open stratospheric balloons operated by the CNES. In situ measurements of H2O, CH4 at high spatial resolution (a few meters) were obtained in the UT and in the TTL. Both flights took place in convective conditions. Layering in the TTL water vapour content is observed with values from 3 ppmv (typical of TTL) to high values of 6 ppmv. To investigate such layering we have used a combination of 3D trajectory calculations (Freitas et al., JGR, 2000) using the mesoscale model BRAMS outputs and Potential vorticity map obtained from the high- resolution PV-advection model MIMOSA (Hauchecorne et al., JGR, 2001). The mesoscale model BRAMS allows us to study processes associated with convective systems, whereas isentropic transport at global scale is investigated with MIMOSA. Backward 3D trajectories have been calculated every km for the two flights. It appears that a very strong uplifting from the ground to 16.5 km has occurred 80 hours before the SF4 flight. This uplifting is associated with a 3 ppmv water vapor layer whereas just above twice more water vapour is observed. This layer with high water vapor is associated with trajectories that skim over the top of the convective region. This leads us to discuss on the ability of convective system to inject water vapour in the TTL. For both flights we investigate also the impact of isentropic transport from extratropical region on TTL water vapour content. It appears that for the SF2 and SF4 flight using the PV maps from MIMOSA model we report filamentation in the TTL and in the UT respectively. This filamentation is associated in the UT with strong dehydration observed at 8-10 km for the SF4 flight and with high water vapour content in the TTL typical of mid- latitude region during SF2 flight.

Computerized urea kinetic modeling to prescribe and monitor delivered Kt/V (pKt/V, dKt/V) in peritoneal dialysis. Fresenius Randomized Dialysis Prescriptions and Clinical Outcome Study (RDP/CO).

PubMed

Gotch, F A; Lipps, B J; Keen, M L; Panlilio, F

1996-01-01

A computerized urea kinetic model of peritoneal urea transport (PACK-PD) has been developed and used to calculate prescription parameters which would result in the prescribed weekly peritoneal urea clearance (pKpt/V) required to achieve levels of weekly summed renal + peritoneal urea clearance (pKprt/ V) targeted at 1.75 and 2.16. Baseline kinetic data were obtained and analyzed with PACK-PD on 88 patients, and the program then used these data to calculate the required pKpt/V and subsequently the delivered Kpt/V (dKpt/V) from the dialysate collections. A total of 108 prescriptions were written and compared to dKpt/V measured over one to 24 months in the 88 patients. Both continuous ambulatory peritoneal dialysis and automated peritoneal dialysis (APD) were studied (APD consisted of PD+ with one or two diurnal and two to four nocturnal cycler exchanges). The correlation of dKpt/V to pKpt/V showed r = 0.93 with 95% confidence limits (CL) on agreement of +/-20% over a range of pKpt/V 0.52-2.55. The 95% CL on (dKpt/V-pKpt/V) were +/-0.30. We concluded: (1) that the prescription can be modeled as reliably in peritoneal dialysis as in hemodialysis (HD) where dKt/V and pKt/V agree to +/-25%, (2) that any individual weekly dKpt/V may vary as much as 0.3-0.4 from pKpt/V, and (3) that frequent measurement of dKpt/V and adjustment of pKpt/V as needed are required (as in HD) to control mean dKpt/V to within +/-10% of mean pKpt/V.

Neural reactivation links unconscious thought to decision-making performance.

PubMed

Creswell, John David; Bursley, James K; Satpute, Ajay B

2013-12-01

Brief periods of unconscious thought (UT) have been shown to improve decision making compared with making an immediate decision (ID). We reveal a neural mechanism for UT in decision making using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. Participants (N = 33) encoded information on a set of consumer products (e.g. 48 attributes describing four different cars), and we manipulated whether participants (i) consciously thought about this information (conscious thought), (ii) completed a difficult 2-back working memory task (UT) or (iii) made an immediate decision about the consumer products (ID) in a within-subjects blocked design. To differentiate UT neural activity from 2-back working memory neural activity, participants completed an independent 2-back task and this neural activity was subtracted from neural activity occurring during the UT 2-back task. Consistent with a neural reactivation account, we found that the same regions activated during the encoding of complex decision information (right dorsolateral prefrontal cortex and left intermediate visual cortex) continued to be activated during a subsequent 2-min UT period. Moreover, neural reactivation in these regions was predictive of subsequent behavioral decision-making performance after the UT period. These results provide initial evidence for post-encoding unconscious neural reactivation in facilitating decision making.

Neural reactivation links unconscious thought to decision-making performance

PubMed Central

Bursley, James K.; Satpute, Ajay B.

2013-01-01

Brief periods of unconscious thought (UT) have been shown to improve decision making compared with making an immediate decision (ID). We reveal a neural mechanism for UT in decision making using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. Participants (N = 33) encoded information on a set of consumer products (e.g. 48 attributes describing four different cars), and we manipulated whether participants (i) consciously thought about this information (conscious thought), (ii) completed a difficult 2-back working memory task (UT) or (iii) made an immediate decision about the consumer products (ID) in a within-subjects blocked design. To differentiate UT neural activity from 2-back working memory neural activity, participants completed an independent 2-back task and this neural activity was subtracted from neural activity occurring during the UT 2-back task. Consistent with a neural reactivation account, we found that the same regions activated during the encoding of complex decision information (right dorsolateral prefrontal cortex and left intermediate visual cortex) continued to be activated during a subsequent 2-min UT period. Moreover, neural reactivation in these regions was predictive of subsequent behavioral decision-making performance after the UT period. These results provide initial evidence for post-encoding unconscious neural reactivation in facilitating decision making. PMID:23314012

CPO Prediction: Accuracy Assessment and Impact on UT1 Intensive Results

NASA Technical Reports Server (NTRS)

Malkin, Zinovy

2010-01-01

The UT1 Intensive results heavily depend on the celestial pole offset (CPO) model used during data processing. Since accurate CPO values are available with a delay of two to four weeks, CPO predictions are necessarily applied to the UT1 Intensive data analysis, and errors in the predictions can influence the operational UT1 accuracy. In this paper we assess the real accuracy of CPO prediction using the actual IERS and PUL predictions made in 2007-2009. Also, results of operational processing were analyzed to investigate the actual impact of EOP prediction errors on the rapid UT1 results. It was found that the impact of CPO prediction errors is at a level of several microseconds, whereas the impact of the inaccuracy in the polar motion prediction may be about one order of magnitude larger for ultra-rapid UT1 results. The situation can be amended if the IERS Rapid solution will be updated more frequently.

Pacific Operational Science and Technology Conference

DTIC Science & Technology

2008-07-17

AOR • Think long term-ten to fifty years • Technology assessment • Systems thinking and interaction • Capitalize on technology futures – Renewable ... Renewable energy • Improved mobility • Transportation security • National competitiveness 24 Managed by UT-Battelle for the Department of Energy...Started Cost Schedule Technical TTA CB-034 Tools and Protocols for Agro Screening Ag Screening Tools 500 4,138 3,500 2,500 2,525 3,163 N CB-011 CB-042 Ag

Applying Public Health Screening Criteria: How Does Universal Newborn Screening Compare to Universal Tumor Screening for Lynch Syndrome in Adults with Colorectal Cancer?

PubMed Central

Cragun, Deborah; DeBate, Rita D.; Pal, Tuya

2014-01-01

Institutions have increasingly begun to adopt universal tumor screening (UTS) programs whereby tumors from all newly diagnosed patients with colorectal cancer (CRC) are screened to identify who should be offered germline testing for Lynch syndrome (the most common cause of hereditary CRC). Given limited information about the impact of universal screening programs to detect hereditary disease in adults, we apply criteria used to evaluate public health screening programs and compares and contrasts UTS with universal newborn screening (NBS) for the purpose of examining ethical implications and anticipating potential outcomes of UTS. Both UTS and a core set of NBS conditions clearly meet most of the Wilson and Jungner screening criteria. However, many state NBS panels include additional conditions that do not meet several of these criteria, and there is currently insufficient data to confirm that UTS meets some of these criteria. Comparing UTS and NBS with regard to newer screening criteria raises additional issues that require attention for both UTS and NBS. Comparisons also highlight the importance of evaluating the implementation of genomic tests to ensure or improve their effectiveness at reducing morbidity and mortality while minimizing potential harms. PMID:25323653

Impact of aspirin on trophoblastic invasion in women with abnormal uterine artery Doppler at 11-14 weeks: a randomized controlled study.

PubMed

Scazzocchio, E; Oros, D; Diaz, D; Ramirez, J C; Ricart, M; Meler, E; González de Agüero, R; Gratacos, E; Figueras, F

2017-04-01

Defective trophoblastic invasion is a key feature in many cases of pre-eclampsia (PE). Uterine artery (UtA) Doppler is a validated non-invasive proxy for trophoblastic invasion. The aim of this study was to explore whether low-dose aspirin, administered from the first trimester, improves trophoblastic invasion, evaluated by UtA Doppler during the second and third trimesters in women defined as high risk by abnormal first-trimester UtA Doppler. This randomized Phase-II study had a triple-blind, parallel-arm, controlled design. Singleton pregnancies with abnormal mean UtA Doppler at 11-14 weeks and absence of other major risk factors for PE received 150 mg extended-release aspirin or identical-appearing placebo tablets from study inclusion to 28 weeks. Main outcome measure was UtA pulsatility index (PI) at 28 weeks' gestation. Secondary outcomes included frequency of development of PE and growth restriction/small-for-gestational age (SGA). A total of 155 women completed the follow-up and were analyzed. No difference in mean UtA-PI was found between women in the aspirin and placebo groups at 28 weeks (mean UtA-PI Z-score (mean ± SD), 0.99 ± 1.48 vs 0.85 ± 1.25; P = 0.52). Seven women developed PE: four (5%) in the aspirin group and three (4%) in the placebo group. There was a trend toward lower incidence of SGA in the aspirin group (8.8% vs 17.3%; P = 0.11). In women with defective trophoblastic invasion, as reflected by abnormal UtA Doppler, low-dose aspirin started in the first trimester does not have a significant effect on UtA impedance as pregnancy progresses; however, the study was underpowered to detect potential small effects . Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation.

PubMed

Kaur, Gurmeet; Balamurugan, P; Uma Maheswari, C; Anitha, A; Princy, S Adline

2016-01-01

Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25-62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

Role of rumen butyrate in regulation of nitrogen utilization and urea nitrogen kinetics in growing sheep.

PubMed

Agarwal, U; Hu, Q; Baldwin, R L; Bequette, B J

2015-05-01

Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling on the basis of increased expression of urea transporter in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concentrations on N balance, urea kinetics and rumen epithelial proliferation. Wether sheep (n= 4), fitted with a rumen cannula, were fed a pelleted ration (∼165 g CP/kg DM, 10.3 MJ ME/kg DM) at 1.8 × ME requirement. In Exp. 1, sheep were infused intraruminally with either an electrolyte buffer solution (Con-Buf) or butyrate dissolved in the buffer solution (But-Buf) during 8-d periods in a balanced crossover design. In Exp. 2, sheep were infused intraruminally with either sodium acetate (Na-Ac) or sodium butyrate (Na-But) for 9 d. All solutions were adjusted to pH 6.8 and 8.0 in Exp. 1 and 2, respectively, and VFA were infused at 10% of ME intake. [15N2] urea was continuously infused intravenously for the last 5 d of each period, and total urine and feces were collected. In Exp. 1, 2H5-phenylalanine was continuously infused intravenously over the last 12 h, after which a biopsy from the rumen papillae was taken for measurement of fractional protein synthesis rate (FSR). Butyrate infusion treatments increased (P = 0.1 in Exp. 1; P < 0.05 in Exp. 2) the proportion of rumen butyrate, and acetate infusion increased (P < 0.05) rumen acetate. All animals were in positive N balance (4.2 g N/d in Exp. 1; 7.0 g N/d in Exp. 2), but no difference in N retention was observed between treatments. In Exp. 2, urea entry (synthesis) rate was reduced ( < 0.05) by Na-But compared with the Na-Ac control. In Exp. 1, although But-Buf infusion increased the FSR of rumen papillae (35.3% ± 1.08%/d vs. 28.7% ± 1.08%/d; P < 0.05), urea kinetics were not altered by But-Buf compared with Con-Buf. These studies are the first to directly assess the role of butyrate in urea recycling and its effects on rumen papillae protein turnover in growing lambs. Under the feeding conditions used and the rate of continuous butyrate infusion into the rumen in the present studies, butyrate does not affect overall N retention in growing sheep. However, butyrate may play a role in the redistribution of urea N fluxes in the overall scheme of N metabolism.

Accouchements sur utérus cicatriciel en République Démocratique du Congo: épreuve utérine et facteurs déterminants de l’issue

PubMed Central

Momat, Félix Kitenge wa; Zalagile, Pierre Akilimali; Mukalenge, Faustin Chenge; Luboya, Oscar Numbi; Kalala, Cléophas Tshibangu; Mashinda, Désiré; Grangé, Gilles; Mukuku, Olivier; Kaj, Fanny Malonga; Lubamba, Chamy Cham; Bwama, Joseph Bagambe; Mukoko, Célestin Kayembe; Kakoma, Jean Baptiste; Kalungwe, Justin Kizonde

2017-01-01

Introduction L'objectif était d'identifier les principaux facteurs de risque associés à un échec d'épreuve utérine et définir un score prédictif d'accouchement sur utérus cicatriciel en République Démocratique du Congo. Méthodes Étude multicentrique, transversale et analytique des patientes porteuses d'un utérus cicatriciel sur la période du 1er janvier au 31 décembre 2013 dans quatre maternités de la République Démocratique du Congo (RDC). Un modèle de régression logistique a été construit pour identifier les facteurs associés à l'échec de l'épreuve utérine. De ce modèle, un score prédictif a été construit pour prédire l'échec de l'épreuve utérine dans les maternités de la RDC. La courbe ROC a été utilisée pour évaluer la capacité du score construit à identifier les patientes à risque de connaitre un échec de l'épreuve utérine. Le cut off point du score prédictif a été déterminé en fonction de la sensibilité et spécificité optimale via l'index de Youden. Tous les tests ont été réalisés au seuil de signification α=0,05. Résultats Deux types de facteurs explicatifs de l'échec de l'épreuve utérine ont été retenus. Il s'agit d'un facteur sociodémographique (âge maternel) et de trois facteurs obstétricaux (hauteur utérine, présentation du fœtus et rupture prématurée des membranes). Le score de prédiction a été défini pour prédire l'échec de l'épreuve utérine. La construction de ce score s'est basée sur quatre éléments : l'âge maternel, l'état de la poche des eaux à l'admission, la hauteur utérine et la présentation fœtale. Le score minimal est de 4 et le score maximal est de 16. Le seuil est de 7. Un Score total supérieur ou égal à 7 traduit un risque d'échec de l'épreuve utérine. Conclusion L'utilisation de ce score prédictif chez les patientes pourra améliorer la qualité dans les indications de la voie haute, l'augmentation des taux de césariennes prophylactiques ainsi que la meilleure sélection des patientes soumises à l'épreuve utérine. Ceci pourra également contribuer à la réduction de la morbi-mortalité fœto-maternelle liée à la gestion de l'accouchement sur utérus cicatriciels. PMID:28819492

An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A).

PubMed

Obanda, Diana N; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T

2016-02-26

The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation.

Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation

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

Crawford, Susan L.; Cinson, Anthony D.; MacFarlan, Paul J.

2012-08-01

The objective of this investigation was to evaluate the efficacy of ultrasonic testing (UT) for primary water leak path assessments of reactor pressure vessel (RPV) upper head penetrations. Operating reactors have experienced leakage when stress corrosion cracking of nickel-based alloy penetrations allowed primary water into the annulus of the interference fit between the penetration and the low-alloy steel RPV head. In this investigation, UT leak path data were acquired for an Alloy 600 control rod drive mechanism nozzle penetration, referred to as Nozzle 63, which was removed from the North Anna Unit 2 reactor when the RPV head was replacedmore » in 2002. In-service inspection prior to the head replacement indicated that Nozzle 63 had a probable leakage path through the interference fit region. Nozzle 63 was examined using a phased-array UT probe with a 5.0-MHz, eight-element annular array. Immersion data were acquired from the nozzle inner diameter surface. The UT data were interpreted by comparing to responses measured on a mockup penetration with known features. Following acquisition of the UT data, Nozzle 63 was destructively examined to determine if the features identified in the UT examination, including leakage paths and crystalline boric acid deposits, could be visually confirmed. Additional measurements of boric acid deposit thickness and low-alloy steel wastage were made to assess how these factors affect the UT response. The implications of these findings for interpreting UT leak path data are described.« less

Issue des accouchements sur utérus cicatriciel dans un hôpital universitaire au Burkina

PubMed Central

Dembélé, Adama; Tarnagda, Zekiba; Ouédraogo, Jean Louis; Thiombiano, Oumarou; Bambara, Moussa

2012-01-01

Certains auteurs ont tendance à privilégier la césarienne comme méthode de prise en charge d'une parturiente porteuse d'un utérus cicatriciel. D'autres auteurs préconisent un accouchement par voie basse quand des paramètres cliniques précis sont observés. Le but de cette étude est d'analyser la prise en charge et l'issue des accouchements sur utérus cicatriciel au Centre Hospitalier Universitaire Souro Sanou de Bobo-Dioulasso et de la comparer aux différentes approches recommandées. Nous avons menés une étude transversale dans le Département de Gynécologie d'Obstétrique et de Médecine de la Reproduction du Centre Hospitalier Universitaire Sanou Souro de Bobo Dioulasso du 1er août 2006 au 1er août 2007 et a concerné 252 parturientes ayant un utérus cicatriciel parmi 4256 accouchements déroulés pendant la même période. Les accouchements sur utérus cicatriciels ont représenté 5,92 % de l'ensemble des accouchements dans notre département. La moyenne d'âge des patientes était de 26,2 ans et la parité moyenne de 4,3. Une césarienne d'emblée a été pratiquée chez 44% des parturientes ayant un utérus cicatriciel et 56 % parmi elles ont fait l'objet d'une épreuve utérine. Sur l'ensemble des épreuves utérines, 61% des parturientes ont accouché par voie basse. La mortalité maternelle était nulle et La mortalité périnatale était relativement importante. Les conditions d'acceptabilité de la voie basse ont été les mêmes chez toutes les patientes et un check liste a été proposé pour une meilleure prise en charge. L'épreuve utérine en salle d'accouchement doit être la règle à chaque fois que cela est possible chez une parturiente porteuse d'utérus cicatriciel. L’établissement d'un check liste pour accouchement par voie basse sur utérus cicatriciel facilite les prises de décision. PMID:23133695

Cross-Modal Approach for Karaoke Artifacts Correction

NASA Astrophysics Data System (ADS)

Yan, Wei-Qi; Kankanhalli, Mohan S.

In this chapter, we combine adaptive sampling in conjunction with video analogies (VA) to correct the audio stream in the karaoke environment κ= {κ (t) : κ (t) = (U(t), K(t)), t in ({t}s, {t}e)} where t s and t e are start time and end time respectively, U(t) is the user multimedia data. We employ multiple streams from the karaoke data K(t) = ({K}_{V }(t), {K}M(t), {K}S(t)), where K V (t), K M (t) and K S (t) are the video, musical accompaniment and original singer's rendition respectively along with the user multimedia data U(t) = ({U}A(t),{U}_{V }(t)) where U V (t) is the user video captured with a camera and U A (t) is the user's rendition of the song. We analyze the audio and video streaming features Ψ (κ ) = {Ψ (U(t), K(t))} = {Ψ (U(t)), Ψ (K(t))} = {{Ψ }U(t), {Ψ }K(t)}, to produce the corrected singing, namely output U '(t), which is made as close as possible to the original singer's rendition. Note that Ψ represents any kind of feature processing.

Cross-Modal Approach for Karaoke Artifacts Correction

NASA Astrophysics Data System (ADS)

Yan, Wei-Qi; Kankanhalli, Mohan S.

In this chapter, we combine adaptive sampling in conjunction with video analogies (VA) to correct the audio stream in the karaoke environment kappa= {kappa (t) : kappa (t) = (U(t), K(t)), t in ({t}s, {t}e)} where t s and t e are start time and end time respectively, U(t) is the user multimedia data. We employ multiple streams from the karaoke data K(t) = ({K}_{V }(t), {K}M(t), {K}S(t)), where K V (t), K M (t) and K S (t) are the video, musical accompaniment and original singer's rendition respectively along with the user multimedia data U(t) = ({U}A(t),{U}_{V }(t)) where U V (t) is the user video captured with a camera and U A (t) is the user's rendition of the song. We analyze the audio and video streaming features Ψ (kappa ) = {Ψ (U(t), K(t))} = {Ψ (U(t)), Ψ (K(t))} = {{Ψ }U(t), {Ψ }K(t)}, to produce the corrected singing, namely output U ' (t), which is made as close as possible to the original singer's rendition. Note that Ψ represents any kind of feature processing.

Thermal transport and thermopower of bcc U-Mo splat-cooled alloys

NASA Astrophysics Data System (ADS)

Falkowski, M.; Buturlim, V.; Paukov, M.; Havela, L.

2018-05-01

In order to characterize the electron and thermal transport properties in splat-cooled U-T alloys (T is transition metal), we measured the thermopower S and thermal conductivity κ of selected splat-cooled U-Mo alloys with 0, 11, 12.5, 15 and 17 at % Mo concentrations, as a function of temperature. Additionally, we compare our data with the results of S(T) and κ(T) for pure α-U bulk material. Moreover, what particularly motivated us for undertaking above mentioned investigation was the opportunity for prove the functionality of the TTO (Thermal Transport Option) insert of PPMS apparatus for such form of samples. Working with rapidly solidified materials in the form of splats, i.e. foils of typical thickness ∼ 0.2 mm, or even less, we need to test first whether the TTO output can be taken as reliable for the sample geometry, being far from typical bulk bar-shaped samples.

Emergence of late-onset placental dysfunction: relationship to the change in uterine artery blood flow resistance between the first and third trimesters.

PubMed

Llurba, Elisa; Turan, Ozhan; Kasdaglis, Tania; Harman, Chris R; Baschat, Ahmet A

2013-06-01

To test if emergence of third-trimester (T3) placental dysfunction is related to the impedance change in uterine artery blood flow resistance between the first trimester (T1) and T3. Mean T1 and T3 uterine artery (mUtA) pulsatility index (PI) was measured in 1098 singletons. Each patient's individual mUtA-PI change was calculated ([(T3 PI - T1 PI/interval in days)] × 100; ΔmUtA-PI). This parameter and T1 and T3 mUtA-PI z-scores were related to placenta-related disease (PRD) and to constitutionally small neonates (CS). Forty-seven (5%) women had PRD and 83 (8.7%) delivered a CS neonate. T1 and T3 mUtA-PI z-scores were higher with PRD (0.418 versus -0.097 and 1.06 versus -0.13, p < 0.001 for all). Change in mUtA-PI (ΔmUtA PI) was similar for patients with PRD. However, the prevalence of PRD doubled with rising ΔmUtA-PI (11.1% versus 5.2%, p = 0.041). T3 uterine artery Doppler performs significantly better in detecting patients at risk for late-onset PRD than T1 or the gestational age change in uterine artery Doppler resistance This suggests that a proportion of late emerging PRD is not amenable to early screening by uterine artery Doppler. Further research is essential to identify the optimal screening strategy for late-onset placental dysfunction. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Uterine artery blood flow, fetal hypoxia and fetal growth

PubMed Central

Browne, Vaughn A.; Julian, Colleen G.; Toledo-Jaldin, Lillian; Cioffi-Ragan, Darleen; Vargas, Enrique; Moore, Lorna G.

2015-01-01

Evolutionary trade-offs required for bipedalism and brain expansion influence the pregnancy rise in uterine artery (UtA) blood flow and, in turn, reproductive success. We consider the importance of UtA blood flow by reviewing its determinants and presenting data from 191 normotensive (normal, n = 125) or hypertensive (preeclampsia (PE) or gestational hypertension (GH), n = 29) Andean residents of very high (4100–4300 m) or low altitude (400 m, n = 37). Prior studies show that UtA blood flow is reduced in pregnancies with intrauterine growth restriction (IUGR) but whether the IUGR is due to resultant fetal hypoxia is unclear. We found higher UtA blood flow and Doppler indices of fetal hypoxia in normotensive women at high versus low altitude but similar fetal growth. UtA blood flow was markedly lower in early-onset PE versus normal high-altitude women, and their fetuses more hypoxic as indicated by lower fetal heart rate, Doppler indices and greater IUGR. We concluded that, despite greater fetal hypoxia, fetal growth was well defended by higher UtA blood flows in normal Andeans at high altitude but when compounded by lower UtA blood flow in early-onset PE, exaggerated fetal hypoxia caused the fetus to respond by decreasing cardiac output and redistributing blood flow to help maintain brain development at the expense of growth elsewhere. We speculate that UtA blood flow is not only an important supply line but also a trigger for stimulating the metabolic and other processes regulating feto-placental metabolism and growth. Studies using the natural laboratory of high altitude are valuable for identifying the physiological and genetic mechanisms involved in human reproductive success. PMID:25602072

Tolerance of uncertainty: Conceptual analysis, integrative model, and implications for healthcare.

PubMed

Hillen, Marij A; Gutheil, Caitlin M; Strout, Tania D; Smets, Ellen M A; Han, Paul K J

2017-05-01

Uncertainty tolerance (UT) is an important, well-studied phenomenon in health care and many other important domains of life, yet its conceptualization and measurement by researchers in various disciplines have varied substantially and its essential nature remains unclear. The objectives of this study were to: 1) analyze the meaning and logical coherence of UT as conceptualized by developers of UT measures, and 2) develop an integrative conceptual model to guide future empirical research regarding the nature, causes, and effects of UT. A narrative review and conceptual analysis of 18 existing measures of Uncertainty and Ambiguity Tolerance was conducted, focusing on how measure developers in various fields have defined both the "uncertainty" and "tolerance" components of UT-both explicitly through their writings and implicitly through the items constituting their measures. Both explicit and implicit conceptual definitions of uncertainty and tolerance vary substantially and are often poorly and inconsistently specified. A logically coherent, unified understanding or theoretical model of UT is lacking. To address these gaps, we propose a new integrative definition and multidimensional conceptual model that construes UT as the set of negative and positive psychological responses-cognitive, emotional, and behavioral-provoked by the conscious awareness of ignorance about particular aspects of the world. This model synthesizes insights from various disciplines and provides an organizing framework for future research. We discuss how this model can facilitate further empirical and theoretical research to better measure and understand the nature, determinants, and outcomes of UT in health care and other domains of life. Uncertainty tolerance is an important and complex phenomenon requiring more precise and consistent definition. An integrative definition and conceptual model, intended as a tentative and flexible point of departure for future research, adds needed breadth, specificity, and precision to efforts to conceptualize and measure UT. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Broad band energy spectrum and a low frequency QPO from H1743-322 in the hard state revealed by INTEGRAL and Swift observations

NASA Astrophysics Data System (ADS)

Rodriguez, J.; Cadolle Bel, M.; Tomsick, J. A.; Hannikainen, D.; Pottschmidt, K.; Kuulkers, E.; Corbel, S.; Coriat, M.; Goldwurm, A.; Russell, D. M.; Wilms, J.

2011-04-01

Following the report of renewed activity of the microquasar H1743-322 (aka IGR J17464-3213, ATels #3263, #3267) we have triggered a Swift ToO. The observation was performed on April 10, 2011 between 7.9h UT and 16.12h UT, therefore in quasi-simultaneity with the INTEGRAL bulge monitoring program (April 10, 2011 18.0h UT to 21.7h UT). The Swift/XRT was operated in Window Timing mode.

78 FR 63380 - Amendment of Class E Airspace; St. George, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

...-0600; Airspace Docket No. 13-ANM-18] Amendment of Class E Airspace; St. George, UT AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace at St. George Municipal Airport, St. George, UT, by removing the operating hours established by a Notice to...

Simultaneous observation of the poleward expansion of substorm electrojet activity and the tailward expansion of current sheet disruption in the near-earth magnetotail

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Koskinen, H. E. J.; Pulkkinen, T. I.; Bosinger, T.; Mcentire, R. W.; Potemra, T. A.

1993-01-01

A substorm that occurred on 7 June 1985 at 2209 UT for which simultaneous measurements from ground stations and CCE are available is considered. The event occurred during a close conjunction between CCE, the EISCAT magnetometer cross, and the STARE radar, allowing a detailed comparison of satellite and ground-based data. Two discrete activations took place during the first few minutes of this substorm: the expansion phase onset at 2209 UT and an intensification at 2212 UT, corresponding to a poleward expansion of activity. The energetic particle data indicate that the active region of the magnetotail during the 2212 UT intensification was located tailward of the active region at 2209 UT. This is direct evidence for a correspondence between tailward expansion of localized activity in the near-earth magnetotail (current disruption and particle energization) and poleward expansion of activity (electrojet formation) in the ionosphere.

U.S. Army Dugway Proving Ground, UT and the West Desert Test Center

DTIC Science & Technology

2001-04-30

Optic Network •32 Channels of Video •7 Communications Consoles with 20 Radio Nets and Phone Patch •Over 40 Communication Drops & Cell Phones •Centralized... Phone Tower Sites Cell Phone Activation May ‘01 Logistical Support Full Serv ice Com mun ity l Ground Transportation and Maintenance – Vehicle Support...Voice, Data & Video Communications in Mission Control Center •Data Speed: 100 MB/sec •Ethernet Connections •Commercial Power to most Sites Cell

Data and Tools | Research Site Name | NREL

Science.gov Websites

aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo laboris nisi ut aliquip ex ea commodo consequat. Research Topic 1 Lorem Ipsum Tool 1 Lorem Ipsum Facility

78 FR 49116 - Modification of Class E Airspace; Brigham City, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-13

...; telephone (425) 203-4537. SUPPLEMENTARY INFORMATION: History On June 5, 2013, the FAA published in the... extending upward from 700 feet or more above the surface of the earth. * * * * * ANM UT E5 Brigham City, UT...

Major Solar Proton Event during September 24-30, 2001 using Imaging Riometer Technique (P42)

NASA Astrophysics Data System (ADS)

Sharma, A. K.; Vhatkar, R. S.

2006-11-01

sharma_ashokkumar@yahoo.com Major outbursts of mass and energy i.e. a fast full halo CME with speed of 2402 km/sec from region 9632, located on the Sun at S16 E23 was observed at 1030 UT by SOHO/LASCO C3 coronagraph on September 24, 2001. The proton event at greater than 100 MeV began at 1440 UT on 24 September, reached a maximum of 31.2 PFU at 0755 UT on 25 September and ended at 1940 UT on 26 September 2001. The protons event at greater than 10 MeV began at 1215 UT on 24 September, reached a maximum of 12,900 PFU at 2235 UT on 25 September and ended at 1710 UT on 30 September 2001. These extremely high energetic protons accelerated during CMEs produces significant ionization in the D region of the ionosphere at high latitudes. Increase in ionization in the D region causes cosmic noise absorption. The major Polar Cap Absorption (PCA) observed during SEPTEMBER 24 -30, 2001 will be discussed in this paper. Imaging riometer observations were made from Kilpisjarvi (69.05oN; 20.79oW), Northern Finland during the PCA event. For this the remote and insitu data have been used. The imaging riometer for ionospheric studies (IRIS) is used to quantify the intensity, time of occurrence and location of CME effects on the ionosphere.

VizieR Online Data Catalog: Discovery of 2 hot Jupiters KELT-14b & KELT-15b (Rodriguez+, 2016)

NASA Astrophysics Data System (ADS)

Rodriguez, J. E.; Colon, K. D.; Stassun, K. G.; Wright, D.; Cargile, P. A.; Bayliss, D.; Pepper, J.; Collins, K. A.; Kuhn, R. B.; Lund, M. B.; Siverd, R. J.; Zhou, G.; Gaudi, B. S.; Tinney, C. G.; Penev, K.; Tan, T. G.; Stockdale, C.; Curtis, I. A.; James, D.; Udry, S.; Segransan, D.; Bieryla, A.; Latham, D. W.; Beatty, T. G.; Eastman, J. D.; Myers, G.; Bartz, J.; Bento, J.; Jensen, E. L. N.; Oberst, T. E.; Stevens, D. J.

2018-04-01

Spectroscopic observations of KELT-14 and KELT-15 were carried out using the CYCLOPS2 fiber feed with the UCLES spectrograph instrument on the Anglo-Australian Telescope (AAT) over two observing runs: UT 2015 February 02-UT 2015 March 01 and UT 2015 May 6-UT 2015 May 13. The instrumental set-up and observing strategy for these observations closely follow that described in earlier CYCLOPS RV papers (Addison et al. 2013ApJ...774L...9A, 2014ApJ...792..112A). CORALIE is a fiber-fed echelle spectrograph (Queloz et al. 2001Msngr.105....1Q) attached to the Swiss 1.2 m Leonard Euler telescope at the ESO La Silla Observatory in Chile. It has a spectral resolution of R~60000, a wavelength range of 3900-6800 Å, and is able to measure radial velocities of bright stars to a precision of 3 m/s or better (Pepe et al. 2002, J/A+A/388/632). We obtained spectra at five epochs of KELT-15 from UT 2015 September 02 to UT 2015 September 14. (3 data files).

Observations of Eyjafjallajökull eruption's plume at Potenza EARLINET station

NASA Astrophysics Data System (ADS)

Mona, Lucia; Amodeo, Aldo; Boselli, Antonella; Cornacchia, Carmela; D'Amico, Guiseppe; Giunta, Aldo; Madonna, Fabio; Pappalardo, Gelsomina

2010-05-01

Eyjafjallajökull is one of the smallest glacier in Iceland. After seismic activity recorded during December 2009, a first eruption started on 20 March, between 22:30 and 23:30 UT. After a brief stop, a new phase of the Eyjafjallajökull eruption started around midnight on April 14, where melt penetrated its way to the central crater beneath the glacier. An eruption plume was observed in the early morning on 14 April. Ash loaded eruption plume rose to more than 8 km height, deflected to the East by westerly winds. Eruptive activity continued in the following days until 23 April with variable maximum height (between 8 and 2 km a.s.l.). Until 27 April, a plume is always visible in proximity of the volcano. On 15 April, the eruption plume reaches continental Europe with closure of airspace over large part of Northern Europe. In the following days, airspace was closed also in some regions of Southern Europe. On 15 April, 10:00 UT CNR-IMAA, Potenza distributed an alert to EARLINET stations informing about a large amount of ash is directing towards North-West of Europe. Even if EARLINET is not an operational, but research oriented, network, almost all the EARLINET stations followed the event performing measurements whenever weather conditions allow it. Because of their proximity to the source, England and Scandinavian countries are of course the most involved in the transported ash arrival. Accordingly to the MetOffice forecasts, the ash plume would have to reach Central Europe on 16 April. The transport toward South was almost blocked by the Alps. A different scenario is forecasted by MetOffice for 20-21 April when the arrival of the volcanic plume is forecasted down to the Southern Italy. At CNR-IMAA, the atmospheric observatory (CIAO) followed the event by means of all available instruments, including EARLINET multi-wavelength lidars, cloud-radar, microwave profiler and AERONET sun-photometer. Low clouds and rain did not permit measurements over Potenza for the period starting from the distributed alert on 15 April until the evening of 19 April. Since 19 April, measurements were performed almost continuously, with breaks only for light rain and low clouds, until 22 April evening when intense rain started again. During the whole observation period aerosol content is not negligible in the free troposphere with sparse aerosols distributed between 3 and 8 km a.s.l. In addition thin layers are distinguishable in the reported temporal evolution at different times and altitudes (e.g. descending layer between 10 and 5 km on 21 April, 00:00 UT -14:00 UT). The most intense aerosol return above the PBL is observed on 20 April around 22:20 UT at about 4 km a.s.l. Ancillary information confirm the volcanic origin of the selected layer. Accordingly to DREAM forecast, no dust should be present over Italy for this day. HYSPLIT backtrajectories show that the observed layer comes from Northern Europe, probably from Iceland. In the following hours, the volcanic layer went down in altitude, mixing with the underlying local aerosol layer. ACKNOWLEDGMENTS The financial support for EARLINET by the European Commission under grant RICA-025991 is gratefully acknowledged. The authors thank NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT backtrajectory analysis, the Barcelona Supercomputing Center for DREAM forecasts, NASA for MODIS image and MetOffice for forecast of volcano plume dispersion.

Very high cloud detection in more than two decades of HIRS data

NASA Astrophysics Data System (ADS)

Kolat, Utkan; Menzel, W. Paul; Olson, Erik; Frey, Richard

2013-04-01

This paper reports on the use of High-resolution Infrared Radiation Sounder (HIRS) measurements to infer the presence of upper tropospheric and lower stratospheric (UT/LS) clouds. UT/LS cloud detection is based on the fact that, when viewing an opaque UT/LS cloud that fills the sensor field of view, positive lapse rates above the tropopause cause a more absorbing CO2 or H2O-sensitive spectral band to measure a brightness temperature warmer than that of a less absorbing or nearly transparent infrared window spectral band. The HIRS sensor has flown on 16 polar-orbiting satellites from TIROS-N through NOAA-19 and Metop-A and -B, forming the only 30 year record that includes H2O and CO2-sensitive spectral bands enabling the detection of these UT/LS clouds. Comparison with collocated Cloud-Aerosol Lidar with Orthogonal Polarization data reveals that 97% of the HIRS UT/LS cloud determinations are within 2.5 km of the tropopause (defined as the coldest level in the National Centers for Environmental Prediction Global Data Assimilation System); more clouds are found above the tropopause than below. From NOAA-14 data spanning 1995 through 2005, we find indications of UT/LS clouds in 0.7% of the observations from 60N to 60S using CO2 absorption bands; however, in the region of the Inter-Tropical Convergence Zone (ITCZ), this increases to 1.7%. During El Niño years, UT/LS clouds shift eastward out of their normal location in the western Pacific region. Monthly trends from 1987 through 2011 using data from NOAA-10 onwards show decreases in UT/LS cloud detection in the region of the ITCZ from 1987 until 1996, increases until 2001, and decreases thereafter.

Observed Changes in Upper-Tropospheric Water Vapor Transport From Satellite Measurements During the Summers of 1987 and 1988

NASA Technical Reports Server (NTRS)

Lerner, Jeffrey A.; Jedlovee, Gary J.; Atkinson, Robert J.

1998-01-01

The research described below focuses on the use of satellite measurements to monitor both monthly and interannual changes in UT (upper tropospheric) water vapor transport. The GOES-7 Pathfinder data set is used to estimate both winds and humidity during the summers (JJA) of 1987 and 1988. These two summers are of particular importance to climate variability since they were characterized by a dramatic shift in the Southern Oscillation index (i.e., 1987 as a warm ENSO event and 1988 as a cold La-Nina period) (Arkin, 1988; Ropelewski 1988). The contrasting features of the summers of '87 and '88 are exploited to demonstrate the utility of satellite wind and humidity estimates to analyze the role of water vapor in climate change.

Polar Electrodynamics During the 14-16 July 2012 Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Anderson, B. J.; Merkin, V. G.; Korth, H.; Dyrud, L. P.; Barnes, R. J.; Ruohoniemi, J. M.; Gjerloev, J. W.; Fentzke, J.

2012-12-01

We present an analysis of the Birkeland current dynamics observed by AMPERE during the CME-driven geomagnetic storm of 14-16 July, 2012, when the provisional Dst reached -125 nT from 17 to 19 UT on 15 July. The CME magnetic cloud presented a consistently southward IMF lasting over 30 hours, affording an opportunity to examine the system response under sustained, steady forcing. The shock arrived at ACE at 1725 UT on 14 July 2012 when the proton speed increased from 390 to 640 km/s by 1738 UT, while the IMF remained southward and intensified from -4 nT to between -10 and -15 nT. By 1810 UT the Birkeland currents increased in intensity by a factor of 5 to 10 and expanded equatorward to about 60N MLAT. During the sheath passage, the IMF rotated multiple times between southward, duskward, dawnard, or northward and the dayside Birkeland currents displayed considerable variability in both intensity and distribution. An impulsive enhancement in nightside currents occurred near 0150 UT on 15 July followed by a second event near 0330 UT, after which the nightside expanded equatorward to 55 MLAT. At ACE the CME sheath was observed until 0551 UT on 15 July when the IMF magnitude increased from 10 nT to 25 nT by 0554 UT and turned consistently southward, BZ = -13 to -15 nT, and anti-sunward, BX = +18 to +23 nT as the CME magnetic cloud arrived. The cloud passage lasted until 1350 UT on 16 July during which time the IMF decreased nearly linearly in time from 27 nT to 10 nT, had a consistently southward orientation, and the proton speed gradually decreased from 650 km/s to 400 km/s. The IMF BZ remained steadily below -14 nT until 0400 UT on 16 July. The first additional current intensification occurred on the dayside at 0620 UT on 15 July. During the next three hours, the currents expanded equatorward of 50N MLAT, and were generally symmetric between dawn and dusk exhibiting pertburbations exceeding 3000 nT. There were multiple, >2000 nT, nightside impulsive events indicating major substorms followed by extended periods displaying two sets of upward-downward current pairs in the evening sector, consistent with a double auroral oval structure. SuperDARN observations, and MHD simulations are used to estimate the time history of energy flux to the ionosphere, quantify the flows, and discuss the possible effects of heavy ion loading and inner magnetosphere dynamics not included in MHD simulations presented here.

An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A)

PubMed Central

Obanda, Diana N.; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T.

2016-01-01

The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation. PMID:26916435

Projections of Demand for Waterborne Transportation, Ohio River Basin, 1980, 1990, 2000, 2020, 2040. Volume 7. Group V. Grains.

DTIC Science & Technology

1980-12-01

but low gluten ; therefore, it is adequrate as animai teed ’,ut makes a poor breadstuff. The ciief ron-teed rie o! barley is as malt, which is barley...For example, hogs and poultry must have large quantities of grain in their ( diets . On the other hand, the ruminant animals, such as cattle and sheep...relatively cheap grain prices, grain, rather than high roughage diets , will be fed to the rumi- nants. In addition to ration variation by species, grain fed to

Comparison of Dawn and Dusk Precipitating Electron Energy Populations Shortly After the Initial Shock for the January 10th, 1997 Magnetic Cloud

NASA Technical Reports Server (NTRS)

Spann, J.; Germany, G.; Swift, W.; Parks, G.; Brittnacher, M.; Elsen, R.

1997-01-01

The observed precipitating electron energy between 0130 UT and 0400 UT of January 10 th, 1997, indicates that there is a more energetic precipitating electron population that appears in the auroral oval at 1800-2200 UT at 030) UT. This increase in energy occurs after the initial shock of the magnetic cloud reaches the Earth (0114 UT) and after faint but dynamic polar cap precipitation has been cleared out. The more energetic population is observed to remain rather constant in MLT through the onset of auroral activity (0330 UT) and to the end of the Polar spacecraft apogee pass. Data from the Ultraviolet Imager LBH long and LBH short images are used to quantify the average energy of the precipitating auroral electrons. The Wind spacecraft located about 100 RE upstream monitored the IMF and plasma parameters during the passing of the cloud. The affects of oblique angle viewing are included in the analysis. Suggestions as to the source of this hot electron population will be presented.

Cluster Observations of Ion Dispersions near the Exterior Cusp

NASA Astrophysics Data System (ADS)

Escoubet, C.; Grison, B.; Berchem, J.; Trattner, K. J.; Pitout, F.; Richard, R. L.; Taylor, M. G.; Laakso, H. E.; Masson, A.; Dunlop, M. W.; Dandouras, I. S.; Reme, H.; Fazakerley, A. N.; Daly, P. W.

2013-12-01

The cusps are the places where the Earth's magnetic field lines, connected to the inner side of the magnetopause, converge. It is therefore the place where signatures of processes occurring near the subsolar point, in the tail lobes, as well as near the dawn and dusk flanks are observed. The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process will take place equatorward (for IMF southward), poleward (for IMF northward) or on the side (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed around 280 km/s and the density around 5 cm-3. The four Cluster spacecraft were still in the "magnetotail" configuration with two perfect tetrahedra of 2000 km around apogee and turning into an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. We will investigate the origin of the injections forming the dispersions and if these can be explained by the reconnection between the interplanetary magnetic field and the Earth's magnetic field.

Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

NASA Astrophysics Data System (ADS)

Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

2012-12-01

Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (<50 μM) compared to growth at 1 mM. Although the ammonia oxidation pathway has not been fully elucidated, we have shown that nitric oxide (NO) appears to be a key intermediate: exponentially growing HL72 produces significant NO and the removal of NO using a scavenger reversibly inhibits growth. In addition to AMO, the HL72 genome also contains sequences for a urease encoded by subunits ureABC and an active urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially consumed NH3 from NH4Cl when both substrates were provided in equal molar concentrations. However, the urease alpha subunit ureC was expressed in both the presence and absence of urea. One consequence of urea hydrolysis is consumption of intracellular protons during the reaction. As ammonia oxidation produces H+, leading to a decrease in pH, the hydrolysis of urea prior to ammonia oxidation may help alleviate metabolism-driven pH change in HL72. A survey of archaeal ureC sequences from metagenomic data covering a range of hydrothermal features revealed that ureolytic potential is common to many Nitrosocaldus-like organisms and is geographically widespread. Measurements of urea from siliceous circumneutral springs indicate that the concentrations are generally low, below 10 μM. One possible explanation for low steady state urea concentrations is high consumption rates by ureolytic organisms. This, combined with abiotic thermal degradation, may mask high fluxes of urea in microbial hot spring communities.

Novel dimer based descriptors with solvational computation for QSAR study of oxadiazoylbenzoyl-ureas as novel insect-growth regulators.

PubMed

Fan, Feng; Cheng, Jiagao; Li, Zhong; Xu, Xiaoyong; Qian, Xuhong

2010-02-01

Molecular aggregation state of bioactive compounds plays a key role in its bio-interactive procedure. In this article, based on the structure information of dimers, the simplest model of molecular aggregation state, and combined with solvational computation, total four descriptors (DeltaV, MR2, DeltaE(1), and DeltaE(2)) were calculated for QSAR study of a novel insect-growth regulator, N-(5-phenyl-1,3,4-oxadiazol-2-yl)-N'-benzoyl urea. Two QSAR models were constructed with r(2) = 0.671, q(2) = 0.516 and r(2) = 0.816, q(2) = 0.695, respectively. It implicates that the bioactivity may strongly depend on the characters of molecular aggregation state, especially on the dimeric transport ability from oil phase to water phase. Copyright 2009 Wiley Periodicals, Inc.

Approaches to reduce urinary tract injury during management of placenta accreta, increta, and percreta: a systematic review.

PubMed

Tam Tam, Kiran Babu; Dozier, James; Martin, James Nello

2012-04-01

A systematic review of the literature was conducted to answer the following question: are there enhancements to standard peripartum hysterectomy technique that minimize unintentional urinary tract (UT) injury in pregnancies complicated by invasive placental attachment (INPLAT)? A PubMed search of English language articles on INPLAT published by June 2010 was conducted. Data regarding the following parameters was required for inclusion in the quantitative analysis of the review's objective: (1) type of INPLAT, (2) details pertaining to medical and surgical management of INPLAT, and (3) complications, if any, associated with management. An attempt was made to identify approaches that may lower the risk of unintentional UT injury. Most cases (285 of 292) were managed by hysterectomy. There were 83 (29%) cases of unintentional UT injury. Antenatal diagnosis of INPLAT lowered the rate of UT injury (39% vs. 63%; P = 0.04). Information regarding surgical technique or medical management was available for 90 cases; 14 of these underwent a standard hysterectomy technique. Methotrexate treatment and 11 modifications of the surgical technique were associated with 16% unintentional UT injury rate as opposed to 57% for standard hysterectomy (P = 0.002). The use of ureteral stents reduced risk of urologic injury (P = 0.01). Multiple logistic regression analysis identified antenatal diagnosis as the significant predictor of an intact UT. Antenatal diagnosis of INPLAT is paramount to minimize UT injury. Utilization of management modifications identified in this review may reduce urologic injury due to INPLAT.

In vitro studies on the effect of physical cross-linking on the biological performance of aliphatic poly(urethane urea) for blood contact applications.

PubMed

Thomas, V; Kumari, T V; Jayabalan, M

2001-01-01

The effect of physical cross-linking in candidate cycloaliphatic and hydrophobic poly(urethane urea) (4,4'-methylenebis(cyclohexylisocyanate), H(12)MDI/hydroxy-terminated polybutadiene, HTPBD/hexamethylenediamine, HDA) and poly(ether urethane urea)s (H(12)MDI/HTPBD-PTMG/HDA) on the in vitro calcification and blood-material interaction was studied. All the candidate poly(urethane urea)s and poly(ether urethane urea)s elicit acceptable hemolytic activity, cytocompatibility, calcification, and blood compatibility in vitro. The studies on blood-material interaction reveal that the present poly(urethane urea)s are superior to polystyrene microtiter plates which were used for the studies on blood-material interaction. The present investigation reveals the influence of physical cross-link density on biological interaction differently with poly(urethane urea) and poly(ether urethane urea)s. The higher the physical cross-link density in the poly(urethane urea)s, the higher the calcification and consumption of WBC in whole blood. On the other hand, the higher the physical cross-link density in the poly(ether urethane urea)s, the lesser the calcification and consumption of WBC in whole blood. However a reverse of the above trend has been observed with the platelet consumption in the poly(urethane urea)s and poly(ether urethane urea)s.

Comparison of rates of ureolysis between Sporosarcina pasteurii and an indigenous groundwater community under conditions required to precipitate large volumes of calcite

NASA Astrophysics Data System (ADS)

Tobler, Dominique J.; Cuthbert, Mark O.; Greswell, Richard B.; Riley, Michael S.; Renshaw, Joanna C.; Handley-Sidhu, Stephanie; Phoenix, Vernon R.

2011-06-01

Ureolysis-driven calcite precipitation has potential to seal porosity and fracture networks in rocks thus preventing groundwater flow and contaminant transport. In this study urea hydrolysis and calcite precipitation rates for the model bacterium Sporosarcina pasteurii were compared with those of indigenous groundwater communities under conditions required to precipitate large volumes of calcite (up to 50 g L -1). We conducted microcosm experiments in oxic artificial and anoxic natural groundwaters (collected from the Permo-Triassic sandstone aquifer at Birmingham, UK) that were inoculated with aerobically grown S. pasteurii. The rate constants for urea hydrolysis, kurea, ranged between 0.06 and 3.29 d -1 and were only affected by inoculum density. Higher Ca 2+ concentration (50-500 mM Ca 2+) as well as differences in fO 2 did not inhibit the ureolytic activity of S. pasteurii and did not significantly impact kurea. These results demonstrate that S. pasteurii has potential to improve calcite precipitation in both oxic and anoxic groundwaters, especially if indigenous communities lack ureolytic activity. Urea hydrolysis by indigenous groundwater communities was investigated in anoxic, natural groundwaters amended with urea and CaCl 2. A notable increase in ureolysis rates was measured only when these communities were stimulated with dilute nutrients (with best results from blackstrap molasses). Furthermore, there was a considerable lag time (12-20 days) before ureolysis and calcite precipitation began. Calculated ureolysis rate constants, kurea, ranged between 0.03 and 0.05 d -1 and were similar to kurea values produced by S. pasteurii at low inoculum densities. Overall, this comparative study revealed that the growth of ureolytic microorganisms present within groundwaters can easily be stimulated to enhance rates of urea hydrolysis in the subsurface, and thus can be used to induce calcite precipitation in these environments. The time required for urea hydrolysis to begin is almost instantaneous if an inoculum of S. pasteurii is included, while it may take several weeks for ureolytic groundwater communities to grow and become ureolytically active.

Hypovolemic intolerance to lower body negative pressure in female runners.

PubMed

Morikawa, T; Sagawa, S; Torii, R; Endo, Y; Yamazaki, F; Shiraki, K

2001-12-01

An attenuated baroreflex response and orthostatic intolerance have been reported in endurance-trained male athletes; however, it is still unknown whether this occurs also in females. The purpose of the present study was to examine whether endurance exercise-trained women had a predisposition to orthostatic compromise, and if so, what causative factor(s) may induce orthostatic intolerance. We studied cardiovascular and hormonal responses to graded lower body negative pressure (LBNP) (0 to -60 mm Hg) in 26 middle-distance female runners (18.6 +/- 0.1 yr) as the exercise-trained (ET) subjects and 23 age-matched untrained (UT) control subjects. On the basis of the occurrence of syncope episodes during LBNP, ET and UT subjects were further allocated to two groups; ET with presyncope (ET+syncope) and without presyncope (ET-syncope) and UT with presyncope (UT+syncope) and without presyncope (UT-syncope). Occurrence of presyncope episodes during LBNP was higher in ET (65.4%, P < 0.05) than that for UT (34.8%). Leg compliance was higher (P < 0.05) in ET than in UT. LBNP reduced stroke volume (SV) more (P < 0.05), increased heart rate (HR) higher (P < 0.05), and increased forearm vascular resistance (FVR) more in ET+syncope as compared with the other groups. Response of vasoactive hormones to LBNP was higher in ET+syncope (P < 0.05) than that of the other groups except for norepinephrine (NE); high in both ET+syncope and UT+syncope. The relationship between SV and NE, an index of sympathetic neuronal response, had no training-related changes during LBNP. We conclude that exercise-trained females have a high incidence of orthostatic intolerance during LBNP, with a greater reduction of SV independent of changes in baroreflex and neurohumoral function. A lower incidence of LBNP intolerance in UT may be accounted for by a lower reduction of SV during LBNP. An increase in leg compliance in the exercise-trained females may play an important role in inducing pronounced reduction of SV and hence the intolerance to LBNP.

Hypoxia-Inducible Factor Pathway Inhibition Resolves Tumor Hypoxia and Improves Local Tumor Control After Single-Dose Irradiation

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

Helbig, Linda; Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden; Koi, Lydia

2014-01-01

Purpose: To study the effects of BAY-84-7296, a novel orally bioavailable inhibitor of mitochondrial complex I and hypoxia-inducible factor 1 (HIF-1) activity, on hypoxia, microenvironment, and radiation response of tumors. Methods and Materials: UT-SCC-5 and UT-SCC-14 human squamous cell carcinomas were transplanted subcutaneously in nude mice. When tumors reached 4 mm in diameter BAY-84-7296 (Bayer Pharma AG) or carrier was daily administered to the animals. At 7 mm tumors were either excised for Western blot and immunohistologic investigations or were irradiated with single doses. After irradiation animals were randomized to receive BAY-84-7296 maintenance or carrier. Local tumor control was evaluatedmore » 150 days after irradiation, and the dose to control 50% of tumors (TCD{sub 50}) was calculated. Results: BAY-84-7296 decreased nuclear HIF-1α expression. Daily administration of inhibitor for approximately 2 weeks resulted in a marked decrease of pimonidazole hypoxic fraction in UT-SCC-5 (0.5% vs 21%, P<.0001) and in UT-SCC-14 (0.3% vs 19%, P<.0001). This decrease was accompanied by a significant increase in fraction of perfused vessels in UT-SCC-14 but not in UT-SCC-5. Bromodeoxyuridine and Ki67 labeling indices were significantly reduced only in UT-SCC-5. No significant changes were observed in vascular area or necrosis. BAY-84-7296 before single-dose irradiation significantly decreased TCD{sub 50}, with an enhancement ratio of 1.37 (95% confidence interval [CI] 1.13-1.72) in UT-SCC-5 and of 1.55 (95% CI 1.26-1.94) in UT-SCC-14. BAY-84-7296 maintenance after irradiation did not further decrease TCD{sub 50}. Conclusions: BAY-84-7296 resulted in a marked decrease in tumor hypoxia and substantially reduced radioresistance of tumor cells with the capacity to cause a local recurrence after irradiation. The data suggest that reduction of cellular hypoxia tolerance by BAY-84-7296 may represent the primary biological mechanism underlying the observed enhancement of radiation response. Whether this mechanism contributes to the improved outcome of fractionated chemoradiation therapy warrants further investigation.« less

Multi-tissue RNA-seq and transcriptome characterisation of the spiny dogfish shark (Squalus acanthias) provides a molecular tool for biological research and reveals new genes involved in osmoregulation.

PubMed

Chana-Munoz, Andres; Jendroszek, Agnieszka; Sønnichsen, Malene; Kristiansen, Rune; Jensen, Jan K; Andreasen, Peter A; Bendixen, Christian; Panitz, Frank

2017-01-01

The spiny dogfish shark (Squalus acanthias) is one of the most commonly used cartilaginous fishes in biological research, especially in the fields of nitrogen metabolism, ion transporters and osmoregulation. Nonetheless, transcriptomic data for this organism is scarce. In the present study, a multi-tissue RNA-seq experiment and de novo transcriptome assembly was performed in four different spiny dogfish tissues (brain, liver, kidney and ovary), providing an annotated sequence resource. The characterization of the transcriptome greatly increases the scarce sequence information for shark species. Reads were assembled with the Trinity de novo assembler both within each tissue and across all tissues combined resulting in 362,690 transcripts in the combined assembly which represent 289,515 Trinity genes. BUSCO analysis determined a level of 87% completeness for the combined transcriptome. In total, 123,110 proteins were predicted of which 78,679 and 83,164 had significant hits against the SwissProt and Uniref90 protein databases, respectively. Additionally, 61,215 proteins aligned to known protein domains, 7,208 carried a signal peptide and 15,971 possessed at least one transmembrane region. Based on the annotation, 81,582 transcripts were assigned to gene ontology terms and 42,078 belong to known clusters of orthologous groups (eggNOG). To demonstrate the value of our molecular resource, we show that the improved transcriptome data enhances the current possibilities of osmoregulation research in spiny dogfish by utilizing the novel gene and protein annotations to investigate a set of genes involved in urea synthesis and urea, ammonia and water transport, all of them crucial in osmoregulation. We describe the presence of different gene copies and isoforms of key enzymes involved in this process, including arginases and transporters of urea and ammonia, for which sequence information is currently absent in the databases for this model species. The transcriptome assemblies and the derived annotations generated in this study will support the ongoing research for this particular animal model and provides a new molecular tool to assist biological research in cartilaginous fishes.

Multi-tissue RNA-seq and transcriptome characterisation of the spiny dogfish shark (Squalus acanthias) provides a molecular tool for biological research and reveals new genes involved in osmoregulation

PubMed Central

Chana-Munoz, Andres; Jendroszek, Agnieszka; Sønnichsen, Malene; Kristiansen, Rune; Jensen, Jan K.; Bendixen, Christian

2017-01-01

The spiny dogfish shark (Squalus acanthias) is one of the most commonly used cartilaginous fishes in biological research, especially in the fields of nitrogen metabolism, ion transporters and osmoregulation. Nonetheless, transcriptomic data for this organism is scarce. In the present study, a multi-tissue RNA-seq experiment and de novo transcriptome assembly was performed in four different spiny dogfish tissues (brain, liver, kidney and ovary), providing an annotated sequence resource. The characterization of the transcriptome greatly increases the scarce sequence information for shark species. Reads were assembled with the Trinity de novo assembler both within each tissue and across all tissues combined resulting in 362,690 transcripts in the combined assembly which represent 289,515 Trinity genes. BUSCO analysis determined a level of 87% completeness for the combined transcriptome. In total, 123,110 proteins were predicted of which 78,679 and 83,164 had significant hits against the SwissProt and Uniref90 protein databases, respectively. Additionally, 61,215 proteins aligned to known protein domains, 7,208 carried a signal peptide and 15,971 possessed at least one transmembrane region. Based on the annotation, 81,582 transcripts were assigned to gene ontology terms and 42,078 belong to known clusters of orthologous groups (eggNOG). To demonstrate the value of our molecular resource, we show that the improved transcriptome data enhances the current possibilities of osmoregulation research in spiny dogfish by utilizing the novel gene and protein annotations to investigate a set of genes involved in urea synthesis and urea, ammonia and water transport, all of them crucial in osmoregulation. We describe the presence of different gene copies and isoforms of key enzymes involved in this process, including arginases and transporters of urea and ammonia, for which sequence information is currently absent in the databases for this model species. The transcriptome assemblies and the derived annotations generated in this study will support the ongoing research for this particular animal model and provides a new molecular tool to assist biological research in cartilaginous fishes. PMID:28832628

A Microfluidic Study of Megakaryocytes Membrane Transport Properties to Water and Dimethyl Sulfoxide at Suprazero and Subzero Temperatures

PubMed Central

Sun, Sijie; Shu, Zhiquan; Ding, Weiping; Reems, Jo-Anna

2011-01-01

Megakaryocytes (MKs) are the precursor cells of platelets. Cryopreservation of MKs is critical for facilitating research investigations about the biology of this important cell and may help for scaling-up ex-vivo production of platelets from MKs for clinical transfusion. Determining membrane transport properties of MKs to water and cryoprotectant agents (CPAs) is essential for developing optimal conditions for cryopreserving MKs. To obtain these unknown parameters, membrane transport properties of the human UT-7/TPO megakaryocytic cell line were investigated using a microfluidic perfusion system. UT-7/TPO cells were immobilized in a microfluidic system on poly-D-lysine-coated glass substrate and perfused with various hyper-osmotic salt and CPA solutions at suprazero and subzero temperatures. The kinetics of cell volume changes under various extracellular conditions were monitored by a video camera and the information was processed and analyzed using the Kedem–Katchalsky model to determine the membrane transport properties. The osmotically inactive cell volume (Vb=0.15), the permeability coefficient to water (Lp) at 37°C, 22°C, 12°C, 0°C, −5°C, −10°C, and −20°C, and dimethyl sulfoxide (DMSO; Ps) at 22, 12, 0, −10, −20, as well as associated activation energies of water and DMSO at different temperature regions were obtained. We found that MKs have relatively higher membrane permeability to water (Lp=2.62 μm/min/atm at 22°C) and DMSO (Ps=1.8×10−3 cm/min at 22°C) than most other common mammalian cell types, such as lymphocytes (Lp=0.46 μm/min/atm at 25°C). This information could suggest a higher optimal cooling rate for MKs cryopreservation. The discontinuity effect was also found on activation energy at 0°C–12°C in the Arrhenius plots of membrane permeability by evaluating the slope of linear regression at each temperature region. This phenomenon may imply the occurrence of cell membrane lipid phase transition. PMID:22232706

Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation.

PubMed

Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

2017-12-20

Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food fermentation processes. Saccharomyces cerevisiae was dominant in gene transcription for urea biosynthesis and degradation. Lysinibacillus sphaericus was dominant for urea degradation. S. cerevisiae degraded 18% and L. sphaericus degraded 13% of urea in their corresponding single cultures, whereas they degraded 56% of urea in coculture after 12 h. Compared to single cultures, transcription of CAR1, DAL2, and argA, which are related to urea biosynthesis, decreased by 51, 36, and 69% in coculture, respectively. Transcription of DUR1 and ureA, which are related to urea degradation, increased by 227 and 70%, respectively. Thus, coexistence of the two strains promoted degradation of urea via transcriptional regulation of genes related to urea metabolism.

Performance of the Finnish Diabetes Risk Score and a Simplified Finnish Diabetes Risk Score in a Community-Based, Cross-Sectional Programme for Screening of Undiagnosed Type 2 Diabetes Mellitus and Dysglycaemia in Madrid, Spain: The SPREDIA-2 Study.

PubMed

Salinero-Fort, M A; Burgos-Lunar, C; Lahoz, C; Mostaza, J M; Abánades-Herranz, J C; Laguna-Cuesta, F; Estirado-de Cabo, E; García-Iglesias, F; González-Alegre, T; Fernández-Puntero, B; Montesano-Sánchez, L; Vicent-López, D; Cornejo-Del Río, V; Fernández-García, P J; Sánchez-Arroyo, V; Sabín-Rodríguez, C; López-López, S; Patrón-Barandio, P; Gómez-Campelo, P

2016-01-01

To evaluate the performance of the Finnish Diabetes Risk Score (FINDRISC) and a simplified FINDRISC score (MADRISC) in screening for undiagnosed type 2 diabetes mellitus (UT2DM) and dysglycaemia. A population-based, cross-sectional, descriptive study was carried out with participants with UT2DM, ranged between 45-74 years and lived in two districts in the north of metropolitan Madrid (Spain). The FINDRISC and MADRISC scores were evaluated using the area under the receiver operating characteristic curve method (ROC-AUC). Four different gold standards were used for UT2DM and any dysglycaemia, as follows: fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), HbA1c, and OGTT or HbA1c. Dysglycaemia and UT2DM were defined according to American Diabetes Association criteria. The study population comprised 1,426 participants (832 females and 594 males) with a mean age of 62 years (SD = 6.1). When HbA1c or OGTT criteria were used, the prevalence of UT2DM was 7.4% (10.4% in men and 5.2% in women; p<0.01) and the FINDRISC ROC-AUC for UT2DM was 0.72 (95% CI, 0.69-0.74). The optimal cut-off point was ≥13 (sensitivity = 63.8%, specificity = 65.1%). The ROC-AUC of MADRISC was 0.76 (95% CI, 0.72-0.81) with ≥13 as the optimal cut-off point (sensitivity = 84.8%, specificity = 54.6%). FINDRISC score ≥12 for detecting any dysglycaemia offered the best cut-off point when HbA1c alone or OGTT and HbA1c were the criteria used. FINDRISC proved to be a useful instrument in screening for dysglycaemia and UT2DM. In the screening of UT2DM, the simplified MADRISC performed as well as FINDRISC.

Protective effect of Uncaria tomentosa extract against oxidative stress and genotoxicity induced by glyphosate-Roundup® using zebrafish (Danio rerio) as a model.

PubMed

Santo, Glaucia Dal; Grotto, Alan; Boligon, Aline A; Da Costa, Bárbara; Rambo, Cassiano L; Fantini, Emily A; Sauer, Elisa; Lazzarotto, Luan M V; Bertoncello, Kanandra T; Júnior, Osmar Tomazelli; Garcia, Solange C; Siebel, Anna M; Rosemberg, Denis B; Magro, Jacir Dal; Conterato, Greicy M M; Zanatta, Leila

2018-04-01

Oxidative stress and DNA damage are involved in the glyphosate-based herbicide toxicity. Uncaria tomentosa (UT; Rubiaceae) is a plant species from South America containing bioactive compounds with known beneficial properties. The objective of this work was to evaluate the antioxidant and antigenotoxic potential of UT extract in a model of acute exposure to glyphosate-Roundup® (GR) in zebrafish (Danio rerio). We showed that UT (1.0 mg/mL) prevented the decrease of brain total thiols, the increase of lipid peroxidation in both brain and liver, and the decrease of liver GPx activity caused after 96 h of GR (5.0 mg/L) exposure. In addition, UT partially protected against the increase of micronucleus frequency induced by GR exposure in fish brain. Overall, our results indicate that UT protects against damage induced by a glyphosate-based herbicide by providing antioxidant and antigenotoxic effects, which may be related to the phenolic compounds identified in the extract.

Multi-chamber electroosmosis using textile reinforced agar membranes--A promising concept for the future of hemodialysis.

PubMed

Kofler, Markus; Lenninger, Margit; Mayer, Gert; Neuwirt, Hannes; Grimm, Michael; Bechtold, Thomas

2016-01-20

Renal replacement therapy options are limited to hemodialysis and peritoneal dialysis (70% of US patients) or renal transplantation. Diffusion processes are the main physico-chemical principle behind hemodialysis. An alternative way to achieve liquid flow through membranes bases on the electroosmotic flow which is observed as electrokinetic phenomenon in porous membranes which bear surface charges. Agar consists of the non-ionic agarose and the negatively charged agaropectine thus an electroosmotic flux is observed in analytical electrophoresis. In this study the potential electroosmosis on textile reinforced agar membranes as separation method was investigated. Using a five-chamber electrolysis cell and an agar membrane/cellulose fabric composite an intensive electroosmotic flow of 1-2 ml cm(2) h(-1) at 100 mA cell current could be observed. The movement of cations in the negatively charged agar structure led to an intensive electroosmotic flux, which also transported uncharged molecules such as urea, glucose through the membrane. Separation of uncharged low molecular weight molecules is determined by the membrane characteristic. The transport of ions (K(+), PO4(3-), creatinine) and uncharged molecules (urea, glucose) in electroosmotic separation experiments was monitored using a pH 5.5 phosphate electrolyte with the aim to assess the overall transport processes in the electrochemical cell. The results demonstrate the potential of the method for filtration of biological fluids in the absence of external pressure or high shear rates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distinct sources of injections in the polar cusp observed by Cluster

NASA Astrophysics Data System (ADS)

Escoubet, C. Philippe; Reme, Henri; Dunlop, Malcolm; Daly, Patrick; Laakso, Harri; Berchem, Jean; Richard, Robert; Taylor, Matthew; Trattner, Karlheinz; Grison, Benjamin; Dandouras, Iannis; Fazakerley, Andrew; Pitout, Frederic; Masson, Arnaud

The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process takes place equatorward (for IMF southward), poleward (for IMF northward) or on the dusk or dawn sides (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s and the density around 5 cm-3. The four Cluster spacecraft had an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions in the dispersions, we obtain an altitude of the sources of these ions between 14 and 20 RE. Using Tsyganenko model, these sources are located on the dusk flank, past the terminator. The first injection by C3 is seen at approximately the same time as the 2nd injection on C1 but their sources at the magnetopause were separated by more than 10 RE. This would imply that two distinct sources were active at the same time on the dusk flank of the magnetosphere.

Science alliance: A vital ORNL-UT partnership

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

Richmond, C.R.; Riedinger, L.; Garritano, T.

1991-01-01

Partnerships between Department of Energy national laboratories and universities have long been keys to advancing scientific research and education in the United States. Perhaps the most enduring and closely knit of these relationships is the one between Oak Ridge National Laboratory and the University of Tennessee at Knoxville. Since its birth in the 1940's, ORNL has had a very special relationship with UT, and today the two institutions have closer ties than virtually any other university and national laboratory. Seven years ago, ORNL and UT began a new era of cooperation by creating the Science Alliance, a Center of Excellencemore » at UT sponsored by the Tennessee Higher Education Commission. As the oldest and largest of these centers, the Science Alliance is the primary vehicle through which Tennessee promotes research and educational collaboration between UT and ORNL. By letting the two institutions pool their intellectual and financial resources, the alliance creates a more fertile scientific environment than either could achieve on its own. Part of the UT College of Liberal Arts, the Science Alliance is composed of four divisions (Biological Sciences, Chemical Sciences, Physical Sciences, and Mathematics and Computer Science) that team 100 of the university's top faculty with their outstanding colleagues from ORNL.« less

Symmetry Reductions of Fourth-Order Nonlinear Diffusion Equations: Lubrication Model and Some Generalizations

NASA Astrophysics Data System (ADS)

Gandarias, M. L.; Medina, E.

Fourth-order nonlinear diffusion equations appear frequently in the description of physical processes, among these, the lubrication equation ut = (unuxxxx)x or the corresponding modified version ut = unuxxxx play an important role in the study of the interface movements. In this work we analyze the generalizations of the above equations given by ut = (f(u)uxxxx)x, ut = (f(u)uxxxx, and we find that if f(u) = un or f(u) = e-u the equations admit extra classical symmetries. The corresponding reductions are performed and some solutions are characterized.

Proceedings: ecology and management of pinyon-juniper communities within the Interior West; 1997 September 15-18; Provo, UT

Treesearch

Stephen B. Monsen; Richard Stevens

1999-01-01

A symposium held September 15-18,1997, in Provo, UT, and Sanpete County, UT, provided information on the ecology, management, resource values, and restoration of pinyon-juniper communities in the Interior Western United States. The conference was hosted by the USDA Forest Service, Rocky Mountain Research Station and the Utah Division of Wildlife Resources in...

Stability of urea in solution and pharmaceutical preparations.

PubMed

Panyachariwat, Nattakan; Steckel, Hartwig

2014-01-01

The stability of urea in solution and pharmaceutical preparations was analyzed as a function of temperature (25°-60°C), pH (3.11-9.67), and initial urea concentration (2.5%-20%). This study was undertaken to (i) obtain more extensive, quantitative information relative to the degradation of urea in both aqueous and non-aqueous solutions and in pharmaceutical preparations, and (ii) test the effects of initial urea concentration, pH, buffer, and temperature values on urea degradation. The stability analysis shows that urea is more stable at the pH range of 4-8 and the stability of urea decreases by increase in temperature for all pH values. Within the experimental range of temperature and initial urea concentration values, the lowest urea degradation was found with lactate buffer pH 6.0. The urea decomposition rate in solution and pharmaceutical preparations shows the dependence of the initial urea concentrations. At higher initial urea concentrations, the rate of degradation is a decreasing function with time. This suggests that the reverse reaction is a factor in the degradation of concentrated urea solution. For non-aqueous solvents, isopropanol showed the best effort in retarding the decomposition of urea. Since the losses in urea is directly influenced by its stability at a given temperature and pH, the stability analysis of urea by the proposed model can be used to prevent the loss and optimize the operating condition for urea-containing pharmaceutical preparations.

An upper tropospheric "ozone river" from Africa to India detected with the IASI sensor

NASA Astrophysics Data System (ADS)

Barret, B.; Sauvage, B.; Le Flochmoën, E.; De Wachter, E.; Cammas, J.

2011-12-01

Over the Indian Ocean, ozone (O3) profile measurements have shown the frequent occurence of elevated O3 concentrations in the mid- to upper-troposphere during the winter season. In particular O3 peaks reaching 120 ppbv were often found in the UT within shallow layers 1 to 2 km thick just below the tropopause. Some studies have attributed these UT O3 laminae to stratosphere to troposphere exchange (STE) along the subtrobical westerly jet (SWJ). O3 peaks in the mid-troposphere have also been atributed to STE and convective lofting of pollution from the Indian continental outflow. Other studies explain winter mid-tropospheric O3 peaks over the Indian Ocean with the eastward advection of air masses impacted by African biomass burning emissions caused by the propagation of waves along the SWJ. In the present study, we use new spaceborne O3 data together with airborne observations of both O3 and CO to document a strong event of pollution transport from Africa to northern India during early winter, supporting the role of Africa in contributing to tropospheric O3 enhancement over India. Thanks to their unprecedented spatio-temporal coverage, the data from the IASI sensor allowed us to follow a flow of O3 rich air masses from the coast of west Africa across the Arabian Sea. This afro-indian O3 river is corroborated over the north-western coast of India by measurements from the airborne MOZAIC program. The O3-CO relationships derived from MOZAIC data enable an unambiguous discrimination of the air masses encountered by the aircraft. Finally, a transport analysis based on particle dispersion lagrangian modeling link this O3 channel transport to the convective outflow of air masses that have been impacted by the emission of O3 precursors from African biomass burning and lightnings.

A Study of Transport in the Near-Earth Plasma Sheet During A Substorm Using Time-Dependent Large Scale Kinetics

NASA Technical Reports Server (NTRS)

El-Alaoui, M.; Ashour-Abdalla, M.; Raeder, J.; Frank, L. A.; Paterson, W. R.

1998-01-01

In this study we investigate the transport of H+ ions that made up the complex ion distribution function observed by the Geotail spacecraft at 0740 UT on November 24, 1996. This ion distribution function, observed by Geotail at approximately 20 R(sub E) downtail, was used to initialize a time-dependent large-scale kinetic (LSK) calculation of the trajectories of 75,000 ions forward in time. Time-dependent magnetic and electric fields were obtained from a global magnetohydrodynamic (MHD) simulation of the magnetosphere and its interaction with the solar wind and the interplanetary magnetic field (IMF) as observed during the interval of the observation of the distribution function. Our calculations indicate that the particles observed by Geotail were scattered across the equatorial plane by the multiple interactions with the current sheet and then convected sunward. They were energized by the dawn-dusk electric field during their transport from Geotail location and ultimately were lost at the ionospheric boundary or into the magnetopause.

Increased Upper Trapezius Muscle Stiffness in Overhead Athletes with Rotator Cuff Tendinopathy

PubMed Central

Leong, Hio Teng; Hug, François; Fu, Siu Ngor

2016-01-01

Although excessive tension of the upper trapezius (UT) is thought to contribute to rotator cuff tendinopathy, no study examined UT tension in athletes with and without rotator cuff tendinopathy. Here we used UT shear modulus measured using ultrasound shear wave elastography as an index of muscle stiffness/tension. The aims of this study were twofold: 1) to determine whether the UT muscle shear modulus is altered in athletes with rotator cuff tendinopathy compared to asymptomatic athletes, and 2) to detect optimal cut-off points of UT shear modulus in identifying athletes with rotator cuff tendinopathy. Forty-three male volleyball players (17 asymptomatic and 26 with rotator cuff tendinopathy, mean age = 22.9±3.5 years) participated in the study. UT shear modulus was quantified during active arm holding at 30° and 60° of shoulder abduction and passive arm positioning at 0°, 30° and 60° of shoulder abduction. During the active tasks, the UT shear modulus was higher in athletes with rotator cuff tendinopathy than the asymptomatic athletes (p = 0.002), regardless the arm position. During the passive tasks, athletes with rotator cuff tendinopathy exhibited a higher UT shear modulus than asymptomatic athletes only at 0° of shoulder abduction (13.0±2.5 kPa vs 10.2±1.8 kPa, p = 0.001). When considering the active task, an optimal cut-off shear modulus of 12.0 kPa at 30° of shoulder abduction (sensitivity = 0.84, specificity = 0.57, AUC = 0.757, p = 0.008) and 9.5 kPa at 60° of shoulder abduction (sensitivity = 0.88, specificity = 0.67, AUC = 0.816, p = 0.002) was detected. When considering the passive task at 0° of shoulder abduction, a cut-off of 12.2 kPa was found (sensitivity = 0.73, AUC = 0.817, p = 0.001). Findings from the present study show that monitoring passive and active UT muscle shear modulus may provide important information for the prevention/rehabilitation of rotator cuff tendinopathy. PMID:27159276

Increased Upper Trapezius Muscle Stiffness in Overhead Athletes with Rotator Cuff Tendinopathy.

PubMed

Leong, Hio Teng; Hug, François; Fu, Siu Ngor

2016-01-01

Although excessive tension of the upper trapezius (UT) is thought to contribute to rotator cuff tendinopathy, no study examined UT tension in athletes with and without rotator cuff tendinopathy. Here we used UT shear modulus measured using ultrasound shear wave elastography as an index of muscle stiffness/tension. The aims of this study were twofold: 1) to determine whether the UT muscle shear modulus is altered in athletes with rotator cuff tendinopathy compared to asymptomatic athletes, and 2) to detect optimal cut-off points of UT shear modulus in identifying athletes with rotator cuff tendinopathy. Forty-three male volleyball players (17 asymptomatic and 26 with rotator cuff tendinopathy, mean age = 22.9±3.5 years) participated in the study. UT shear modulus was quantified during active arm holding at 30° and 60° of shoulder abduction and passive arm positioning at 0°, 30° and 60° of shoulder abduction. During the active tasks, the UT shear modulus was higher in athletes with rotator cuff tendinopathy than the asymptomatic athletes (p = 0.002), regardless the arm position. During the passive tasks, athletes with rotator cuff tendinopathy exhibited a higher UT shear modulus than asymptomatic athletes only at 0° of shoulder abduction (13.0±2.5 kPa vs 10.2±1.8 kPa, p = 0.001). When considering the active task, an optimal cut-off shear modulus of 12.0 kPa at 30° of shoulder abduction (sensitivity = 0.84, specificity = 0.57, AUC = 0.757, p = 0.008) and 9.5 kPa at 60° of shoulder abduction (sensitivity = 0.88, specificity = 0.67, AUC = 0.816, p = 0.002) was detected. When considering the passive task at 0° of shoulder abduction, a cut-off of 12.2 kPa was found (sensitivity = 0.73, AUC = 0.817, p = 0.001). Findings from the present study show that monitoring passive and active UT muscle shear modulus may provide important information for the prevention/rehabilitation of rotator cuff tendinopathy.

Impacts | Research Site Name | NREL

Science.gov Websites

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Cerebro-renal interactions: impact of uremic toxins on cognitive function.

PubMed

Watanabe, Kimio; Watanabe, Tsuyoshi; Nakayama, Masaaki

2014-09-01

Cognitive impairment (CI) associated with chronic kidney disease (CKD) has received attention as an important problem in recent years. Causes of CI with CKD are multifactorial, and include cerebrovascular disease, renal anemia, secondary hyperparathyroidism, dialysis disequilibrium, and uremic toxins (UTs). Among these causes, little is known about the role of UTs. We therefore selected 21 uremic compounds, and summarized reports of cerebro-renal interactions associated with UTs. Among the compounds, uric acid, indoxyl sulfate, p-cresyl sulfate, interleukin 1-β, interleukin 6, TNF-α, and PTH were most likely to affect the cerebro-renal interaction dysfunction; however, sufficient data have not been obtained for other UTs. Notably, most of the data were not obtained under uremic conditions; therefore, the impact and mechanism of each UT on cognition and central nervous system in uremic state remains unknown. At present, impacts and mechanisms of UT effects on cognition are poorly understood. Clarifying the mechanisms and establishing novel therapeutic strategies for cerebro-renal interaction dysfunction is expected to be subject of future research. Copyright © 2014 Elsevier Inc. All rights reserved.

Serum Amino Acid Profiling in Citrin-Deficient Children Exhibiting Normal Liver Function During the Apparently Healthy Period.

PubMed

Miyazaki, Teruo; Nagasaka, Hironori; Komatsu, Haruki; Inui, Ayano; Morioka, Ichiro; Tsukahara, Hirokazu; Kaji, Shunsaku; Hirayama, Satoshi; Miida, Takashi; Kondou, Hiroki; Ihara, Kenji; Yagi, Mariko; Kizaki, Zenro; Bessho, Kazuhiko; Kodama, Takahiro; Iijima, Kazumoto; Yorifuji, Tohru; Matsuzaki, Yasushi; Honda, Akira

2018-04-14

Citrin (mitochondrial aspartate-glutamate transporter) deficiency causes the failures in both carbohydrate-energy metabolism and the urea cycle, and the alterations in the serum levels of several amino acids in the stages of newborn (NICCD) and adult (CTLN2). However, the clinical manifestations are resolved between the NICCD and CTLN2, but the reasons are still unclear. This study evaluated the serum amino acid profile in citrin-deficient children during the healthy stage. Using HPLC-MS/MS analysis, serum amino acids were evaluated among 20 citrin-deficient children aged 5-13 years exhibiting normal liver function and 35 age-matched healthy controls. The alterations in serum amino acids characterized in the NICCD and CTLN2 stages were not observed in the citrin-deficient children. Amino acids involved in the urea cycle, including arginine, ornithine, citrulline, and aspartate, were comparable in the citrin-deficient children to the respective control levels, but serum urea was twofold higher, suggestive of a functional urea cycle. The blood sugar level was normal, but glucogenic amino acids and glutamine were significantly decreased in the citrin-deficient children compared to those in the controls. In addition, significant increases of ketogenic amino acids, branched-chain amino acids (BCAAs), a valine intermediate 3-hydroxyisobutyrate, and β-alanine were also found in the citrin-deficient children. The profile of serum amino acids in the citrin-deficient children during the healthy stage showed different characteristics from the NICCD and CTLN2 stages, suggesting that the failures in both urea cycle function and energy metabolism might be compensated by amino acid metabolism. In the citrin-deficient children during the healthy stage, the characteristics of serum amino acids, including decrease of glucogenic amino acids, and increase of ketogenic amino acids, BCAAs, valine intermediate, and β-alanine, were found by comparison to the age-matched healthy control children, and it suggested that the characteristic alteration of serum amino acids may be resulted from compensation for energy metabolism and ammonia detoxification.

The Hale-Bopp comet - an unexpected guest

NASA Astrophysics Data System (ADS)

Gorodetchi, Dumitru

A number of 3 photographs are given of the comewt Hale-Bopp made at UT 1997 March 18.0937 (refractor RT-80(80 cm., 1:10); Fomapan T-800 (DT=10 min). 2) UT 1997 March 18.010; Cassegrain-reflector AT -400 (630, 1:16); film 100 ASA (DT=1 min) 3)UT 1997 April 5.8097; telobiectiv Tair -11 (13,5 cm, 1:2.8); Fomapan T-800 (DT =2 min)

SALT Spectroscopic classification of ASASSN-18lp as a dwarf nova

NASA Astrophysics Data System (ADS)

Buckley, D. A. H.; Gromadzki, M.; Dong, Subo; Stanek, K. Z.

2018-06-01

ASASSN-18lp (AT 2018cex) was discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014) on UT 2018-06-05.24 at g 16 mag. It was observed with the Southern African Large Telescope (SALT) using the Robert Stobie Spectrograph on UT 2018-06-05.75 UT (HJD 2458275.2561) employing the PG300 lines/mm grating.

Different weight bearing push-up plus exercises with and without isometric horizontal abduction in subjects with scapular winging: A randomized trial.

PubMed

Choi, Woo-Jeong; Yoon, Tae-Lim; Choi, Sil-Ah; Lee, Ji-Hyun; Cynn, Heon-Seock

2017-07-01

The aim of the present study was to determine whether the application of isometric horizontal abduction (IHA) differentially affected two weight-bearing push-up plus exercises by examining activation of the scapulothoracic muscles in subjects with scapular winging. Fifteen male subjects performed standard push-up plus (SPP) and wall push-up plus (WPP), with and without IHA. Two-way analyses of variance using two within-subject factors were used to determine the statistical significance of observed differences in upper trapezius (UT), pectoralis major (PM), and serratus anterior (SA) muscle activities and UT/SA and PM/SA muscle activity ratios. UT and SA muscle activities were greater during SPP than WPP. PM muscle activity was lower with IHA application. The UT/SA and PM/SA muscle activity ratios were lower during SPP than WPP. The PM/SA muscle activity ratio was lower with IHA application. The results suggest that IHA application using a Thera-Band can effectively reduce PM muscle activity during SPP and WPP exercises. Moreover, the SPP exercise can be used to increase UT and SA muscle activity and reduce the UT/SA and PM/SA muscle activity ratios in subjects with scapular winging. Copyright © 2016 Elsevier Ltd. All rights reserved.

VizieR Online Data Catalog: Sloan i follow-up light curves of HATS-18 (Penev+, 2016)

NASA Astrophysics Data System (ADS)

Penev, K.; Hartman, J. D.; Bakos, G. A.; Ciceri, S.; Brahm, R.; Bayliss, D.; Bento, J.; Jordan, A.; Csubry, Z.; Bhatti, W.; de Val-Borro, M.; Espinoza, N.; Zhou, G.; Mancini, L.; Rabus, M.; Suc, V.; Henning, T.; Schmidt, B.; Noyes, R. W.; Lazar, J.; Papp, I.; Sari, P.

2017-02-01

The star HATS-18 was observed by HATSouth instruments between UT 2011 April 18 and UT 2013 July 21 using the HS-2, HS-4, and HS-6 units at the Las Campanas Observatory in Chile, the High Energy Spectroscopic Survey (H.E.S.S.) site in Namibia, and Siding Spring Observatory (SSO) in Australia, respectively. A total of 5372, 3758, and 4008 images of HATS-18 were obtained with HS-2, HS-4, and HS-6, respectively. The observations were obtained through a Sloan r filter with an exposure time of 240s. We obtained follow-up light curves of HATS-18 using the Las Cumbres Observatory Global Telescope (LCOGT) 1m telescope network. An ingress was observed on UT 2015 July 18 with the SBIG camera and a Sloan i filter on the 1m at the South African Astronomical Observatory (SAAO). A total of 33 images were collected at a median cadence of 201s. A full transit was observed on UT 2016 January 22 with the sinistro camera and a Sloan i filter on the 1m at Cerro Tololo Inter-American Observatory. A total of 61 images were collected at a median cadence of 219s. For the record, we also note that a full transit was observed on UT 2016 January 3 with the SBIG camera on the 1m at SAAO; however, due to tracking and weather problems, we were unable to extract high-precision photometry from these images, and therefore do not include these data in our analysis. The data are available in Table1. Spectroscopic follow-up observations of HATS-18 were carried out with WiFeS on the Australian National University (ANU) 2.3m telescope and with the Fiber-fed Extended Range Optical Spectrograph (FEROS) on the MPG 2.2m. A total of three spectra were obtained with WiFeS between UT 2015 February 28 and UT 2015 March 2, two at a resolution of R=Δλ/λ=7000, and one at R=3000. We obtained six R=48000 spectra with FEROS between UT 2015 June 12 and UT 2015 June 20. The data are provided in Table2. (2 data files).

The InterCon network: a program for education partnerships at the University of Texas-Houston Health Science Center.

PubMed

Castro, G A; Bouldin, P A; Farver, D W; Maugans, L A; Sanders, L C; Booker, J

1999-04-01

The University of Texas-Houston Health Science Center (UT-Houston) has created programs and activities to address the state's pressing needs in minority education. Through InterCon, a network of universities and K-12 schools, UT-Houston works with its partners to identify competitive candidates in the current pool of minority graduates with bachelor's degrees and to help them--along with their non-minority counterparts--progress in their education. Another objective is to expand the pool of minorities underrepresented in medicine who complete high school and go to college. In 1994 UT-Houston and Prairie View A&M University created a collaborative venture to provide new educational opportunities at UT-Houston for Prairie View's predominantly African American students. A three-track summer internship program--a result of that collaboration--has since been expanded to partnerships with other minority and majority universities throughout Texas. In 1998, for example, 108 undergraduate students from these universities (and 40 other universities nationwide) participated in research, professional, and administrative summer internships at UT-Houston. The InterCon network also has partnerships with K-12 schools. UT-Houston works with inner-city, suburban, and rural school districts to develop education models that can be transferred throughout the state. The partnerships deal with helping to teach basic academic skills and computer literacy, improve science-related instruction, meet demands for health promotion materials and information for school-initiated health and wellness programs, and develop distance-learning paradigms. UT-Houston views InterCon as a program helping Texas institutions to engage and adapt to the socioeconomic factors, demographic changes, and technology explosion that currently challenge public education.

Deposits from Creams Containing 20% (w/w) Urea and Suppression of Crystallization (Part 2): Novel Analytical Methods of Urea Accumulated in the Stratum Corneum by Tape stripping and Colorimetry.

PubMed

Goto, Norio; Morita, Yutaka; Terada, Katsuhide

2016-01-01

The transfer of urea from a urea formulation to the stratum corneum varies with the formulation base and form, and impacts the formulation's therapeutic effect. Consequently, determining the amount of urea transferred is essential for developing efficient formulations. This study assessed a simple method for measuring the amount of urea accumulated in the stratum corneum. Conventional methods rely on labeling urea used in the formulation with radiocarbon ((14)C) or other radioactive isotopes (RIs), retrieving the transferred urea from the stratum corneum by tape stripping, then quantitating the urea. The handling and use of RIs, however, is subject to legal regulation and can only be performed in sanctioned facilities, so methods employing RIs are neither simple nor convenient. We therefore developed a non-radiolabel method "tape stripping-colorimetry (T-C)" that combines tape stripping with colorimetry (urease-glutamate dehydrogenase (GLDH)) for the quantitative measurement of urea. Urea in the stratum corneum is collected by tape stripping and measured using urease-GLDH, which is commonly used to measure urea nitrogen in blood tests. The results indicate that accurate urea measurement by the T-C method requires the application of 1400 mg (on hairless rats) of a 20% urea solution on a 50 cm(2) (5×10 cm) area. Further, we determined the amount of urea accumulated in the stratum corneum using formulations with different urea concentrations, and the time course of urea accumulation from formulations differing in the rate of urea crystallization. We demonstrate that the T-C method is simple and convenient, with no need for (14)C or other RIs.

Changes in milk urea around insemination are negatively associated with conception success in dairy cows.

PubMed

Albaaj, A; Foucras, G; Raboisson, D

2017-04-01

Dietary protein levels are a risk factor for poor reproductive performance. Conception is particularly impaired in cases of high blood or milk urea. The objective of this study was to investigate the association between conception and low milk urea or changes in milk urea around artificial insemination (AI). Data were obtained from the French Milk Control Program for a 4-yr period (2009-2012). Milk urea values between 250 and 450 mg/kg (4.3 and 7.7 mM) were considered intermediate (I), and values ≤150 mg/kg (2.6 mM) were considered low (L). Milk urea values before and after each AI were allocated into 4 classes representing the dynamics of milk urea (before-after; I-I, I-L, L-I, and L-L). Subclinical ketosis was defined using milk fat and protein contents before AI as proxies. A logistic regression with a Poisson correction and herd as a random variable was then performed on data from Holstein or all breeds of cows. The success of conception was decreased [relative risk (95% confidence interval) = 0.96 (0.94-0.99)] in low-urea cows compared with intermediate-urea cows after AI; no significant association was found for urea levels before AI. When combining data on urea before and after AI, I-L urea cows exhibited a 5 to 9% decrease in conception compared with I-I urea cows, and L-I urea cows showed no difference in conception success compared with I-I urea cows. A decreased conception success for L-L urea cows compared with I-I urea cows was observed for the analysis with cows of all breeds. This work revealed that a decrease in urea from intermediate (before AI) to low (after AI) is a risk factor for conception failure. Surveys of variation in milk urea in dairy cows close to breeding are highly recommended. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Cluster Observations of Particle Injections in the Exterior Cusp

NASA Astrophysics Data System (ADS)

Escoubet, C. P.; Grison, B.; Berchem, J.; Trattner, K. J.; Lavraud, B.; Pitout, F.; Soucek, J.; Richard, R. L.; Laakso, H. E.; Masson, A.; Dunlop, M. W.; Dandouras, I. S.; Reme, H.; Fazakerley, A. N.; Daly, P. W.

2014-12-01

The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process takes place equatorward (for IMF southward), poleward (for IMF northward) or on the dusk or dawn sides (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s with the density of order 5 cm-3. The four Cluster spacecraft had an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions, which leads to energy dispersions, we obtain distances of the ion sources between 14 and 20 RE from the spacecraft. Using Tsyganenko model, we find that these sources are located on the dusk flank, past the terminator. The first injection by C3 is seen at approximately the same time as the 2nd injection on C1 but their sources at the magnetopause were separated by more than 7 RE. This would imply that two distinct sources were active at the same time on the dusk flank of the magnetosphere. In addition, a flow reversal was observed at the magnetopause on C4 which would be an indication that reconnection is taking place near the exterior cusp.

Determination of urea kinetics by isotope dilution with [13C]urea and gas chromatography-isotope ratio mass spectrometry (GC-IRMS) analysis.

PubMed

Kloppenburg, W D; Wolthers, B G; Stellaard, F; Elzinga, H; Tepper, T; de Jong, P E; Huisman, R M

1997-07-01

1. Stable urea isotopes can be used to study urea kinetics in humans. The use of stable urea isotopes for studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material. We devised a urea dilution for measurement of the distribution volume, production rate and clearance of urea in healthy subjects and renal failure patients using the inexpensive single labelled [13C]urea isotope with subsequent analysis by headspace chromatography-isotope ratio MS (GC-IRMS) of the [13C]urea enrichment. 2. The method involves measurement of the molar percentage excess of [13C]urea in plasma samples taken over a 4 h period after an intravenous bolus injection of [13C]urea. During the sample processing procedure, the plasma samples together with calibration samples containing a known molar percentage excess of [13C]urea are acidified with phosphoric acid to remove endogenous CO2, and are subsequently incubated with urease to convert the urea present in the plasma samples into CO2. The 13C enrichment of the generated CO2 is analysed by means of GC-IRMS. This method allows measurement of the molar percentage excess of [13C]urea to an accuracy of 0.02%. 3. Reproducibility studies showed that the sample processing procedure [within-run coefficient of variation (CV) < 2.8% and between-run CV < 8.8%] and the GC-IRMS analysis (within-day CV < 1.3% and between-day CV < 1.3%) could be repeated with good reproducibility. 4. In clinical urea kinetic studies in a healthy subject and in a renal failure patient without residual renal function, reproducible values of the distribution volume, production rate and clearance of urea were determined using minimal amounts of [13C]urea (25-50 mg). 5. Because only low [13C]urea enrichments are needed in this urea dilution method using GC-IRMS analysis, the costs of urea kinetic studies are reduced considerably, especially in patients with renal failure.

Using GMD Data, AIRS Measurements, and the NASA Chemistry-Climate Model to Reveal Regional and Seasonal Variation of Methane

NASA Astrophysics Data System (ADS)

Steele, K. J.; Duncan, B. N.; Warner, J. X.; Nielsen, J. E.

2010-12-01

The concentration of methane (CH4) has more than doubled in the atmosphere since the preindustrial era due to a change in source-sink interactions. Many studies have aimed to quantify CH4 source contributions, but 1) the long tropospheric lifetime of CH4, resulting in a high background concentration, 2) along with sources often having overlapping distributions, and 3) the uncertainty in the chemical sink of CH4 with the hydroxyl radical makes it difficult to constrain inputs to the CH4 budget. The purpose of this study was to use a variety of observations in conjunction with the NASA GEOS-5 climate-chemistry model (CCM) to better understand regional and seasonal variation in atmospheric CH4. Seasonal variation in surface in situ data from the NOAA ESRL Global Monitoring Division (GMD) and data from the Japanese Airlines (JAL) in the upper troposphere (UT) were compared to satellite observations recorded by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite, which is most sensitive to CH4 in the UT. There was more variability in CH4 at the GMD sites than in the JAL data or AIRS because the GMD sites are closer to the source. As the CH4 is lofted into the UT, it mixes with the background CH4 so the seasonal variation is dampened. The JAL data followed the AIRS observations as expected. There was less variability in all measurements in the Southern Hemisphere and over oceans because these areas are farther away from sources. While the observations from AIRS, JAL flights, and the GMD sites provide valuable information regarding source locations and atmospheric CH4 concentration, it is important to understand which CH4 sources have the largest contribution to CH4 emissions in different regions of the world and the influence of these sources on the global CH4 cycle. Model output from the GEOS-5 CCM was used to monitor individual CH4 sources (e.g. from rice production, wetlands, biofuel use, etc.) as they are transported from the surface to the UT. The model revealed that variation in source strength is dependent on the site location in relation to the source strength. Assessing CH4 source contributions to the UT revealed that variability is affected by seasonal variation in the sources convolved with seasonal variation in deep convection. More work is needed in order to constrain sources of atmospheric CH4. However, surface and tropospheric in situ data can be used to validate AIRS observations so that CH4 can be monitored at a global scale, and CCM output can aid in determining which sources have the largest contribution to atmospheric CH4.

The Use of Daily Geodetic UT1 and LOD Data in the Optimal Estimation of UT1 and LOD With the JPL Kalman Earth Orientation Filter

NASA Technical Reports Server (NTRS)

Freedman, A. P.; Steppe, J. A.

1995-01-01

The Jet Propulsion Laboratory Kalman Earth Orientation Filter (KEOF) uses several of the Earth rotation data sets available to generate optimally interpolated UT1 and LOD series to support spacecraft navigation. This paper compares use of various data sets within KEOF.

75 FR 62461 - Revocation and Establishment of Class E Airspace; St. George, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

...-0660; Airspace Docket No. 10-ANM-4] Revocation and Establishment of Class E Airspace; St. George, UT... Class E airspace at St. George, UT, as the airport will be closing, eliminating the need for controlled airspace. This action will establish Class E airspace for the new St. George Municipal Airport located to...

76 FR 28074 - Notice of Inventory Completion: Utah Museum of Natural History, Salt Lake City, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

... Museum of Natural History, Salt Lake City, UT AGENCY: National Park Service, Interior. ACTION: Notice... of the Utah Museum of Natural History, Salt Lake City, UT. The human remains were removed from Snow... sole responsibility of the museum, institution, or Federal agency that has control of the Native...

Isotopic studies of urea metabolism in rabbits

PubMed Central

Regoeczi, E.; Irons, L.; Koj, A.; McFarlane, A. S.

1965-01-01

1. The half-life of [15N]urea was found to be significantly longer than that of [14C]urea injected at the same time, the differences being due to endogenous catabolism of urea, which is accompanied by little or no reutilization of 14C but is approx. 20% for 15N. [15N]Urea therefore appears to be valueless as an indicator of nitrogen metabolism unless the extents of endogenous catabolism of urea and of fractional reutilization of 15N can be separately estimated. 2. Though measurements of the radioactivity of expired 14CO2 confirmed the existence of considerable urea catabolism these could not be used for quantitative assessments. 3. Alternative graphical methods based on [14C]urea specific activities in plasma and urine samples were used to calculate the fraction of urea production that is excreted. Values by the two methods were in good agreement and showed that some animals excrete less than half the urea that they produce. 4. Specific activity differences between simultaneous samples of urinary and plasma urea reflect the presence of a pool of urea in the kidney that is not in equilibrium with the body urea pool. Calculations indicate the presence of urea in the kidney that in some cases may represent as much as 15% of the body pool, and in two animals in which post-mortem renal analyses were performed the masses of urea found agreed closely with the calculated values. 5. A model for urea metabolism is proposed that includes this pool in the excretory pathway. The related theory is shown to be adequate to explain the shape of the specific activity curves of urinary urea from the time of injection and the constant delay of the specific activity of urinary urea, relative to that of plasma urea, that is observed after a short preliminary equilibration period. 6. The body urea pool was calculated from the activity retained at 1·5hr. by excluding renal activity and the corrected specific activity of plasma urea at the same time. The urea pool was calculated to be distributed at the plasma concentration in a substantially smaller water volume than that found by injecting tritiated water in five animals. Reasons for this are discussed. 7. Urea synthesis rates calculated from the pool values are in close agreement with rates calculated from the mass of urea recovered in the urine and the fraction of newly synthesized urea that is excreted. PMID:14340103

Disposition of feedwater nozzle UT indications in a BWR

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

Leshnoff, S.D.; Orski, M.A.

A technical logic is developed, which justifies the disposition of feedwater nozzle ultrasonic testing (UT) indications in order to return to operation without visual inspection of the vessel inside surface. Present regulatory guidance is to inspect the inside surface from the inside if a reportable indication is found. A highly sensitive, tomographic UT technique, developed by Kraftwerk Union, is used to detect and size machined notches in the blend radius and bore regions of a full-sized feedwater nozzle mock-up.

Short communication: Urea hydrolysis in dairy cattle manure under different temperature, urea, and pH conditions.

PubMed

Moraes, L E; Burgos, S A; DePeters, E J; Zhang, R; Fadel, J G

2017-03-01

The objective of the study was to quantify the rate of urea hydrolysis in dairy cattle manure under different initial urea concentration, temperature, and pH conditions. In particular, by varying all 3 factors simultaneously, the interactions between them could also be determined. Fresh feces and artificial urine solutions were combined into a slurry to characterize the rate of urea hydrolysis under 2 temperatures (15°C and 35°C), 3 urea concentrations in urine solutions (500, 1,000, and 1,500 mg of urea-N/dL), and 3 pH levels (6, 7, and 8). Urea N concentration in slurry was analyzed at 0.0167, 1, 2, 4, 6, 8, 12, 16, 20, and 24 h after initial mixing. A nonlinear mixed effects model was used to determine the effects of urea concentration, pH, and temperature treatments on the exponential rate of urea hydrolysis and to predict the hydrolysis rate for each treatment combination. We detected a significant interaction between pH and initial urea level. Increasing urea concentration from 1,000 to 1,500 mg of urea-N/dL decreased the rate of urea hydrolysis across all pH levels. Across all pH and initial urea levels, the rate of urea hydrolysis increased with temperature, but the effect of pH was only observed for pH 6 versus pH 8 at the intermediate initial urea concentration. The fast rates of urea hydrolysis indicate that urea was almost completely hydrolyzed within a few hours of urine mixing with feces. The estimated urea hydrolysis rates from this study are likely maximum rates because of the thorough mixing before each sampling. Although considerable mixing of feces and urine occurs on the barn floor of commercial dairy operations from cattle walking through the manure, such mixing may be not as quick and thorough as in this study. Consequently, the urea hydrolysis rates from this study indicate the maximum loss of urea and should be accounted for in management aimed at mitigating ammonia emissions from dairy cattle manure under similar urea concentration, pH, and temperature conditions reported in this experiment. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of ultrasonic pretreatments on quality, energy consumption and sterilization of barley grass in freeze drying.

PubMed

Cao, Xiaohuang; Zhang, Min; Mujumdar, Arun S; Zhong, Qifeng; Wang, Zhushang

2018-01-01

Barley grass is a plant resource for rehabilitation therapy. Its processing requires retaining nutrition well for rehabilitation cure of consumers. To meet the aim as well as low energy consumption and microbiological safety of products, ultrasonic treatments (UT) were applied to bathing materials at different power levels (10, 30, 45, 60W/L) for 10mins. After treatments, the bathed barley grass (100g) was freeze-dried under vacuum -0.09MPa with fixed power of 2W/g. Parameters of color, microbial colony, energy consumption, glass transition temperature, moisture content, water activity, taste substances, contents of flavonoid and chlorophyll were determined after drying. In contrast with no treatment case, UT (45W/L) decreased drying time by 14% and decreased energy consumption by 19%; UT (60W/L) decreased total microbial colonies by 33%. Also, UT (30W/L) yielded contents of flavonoid (9.2/kg) and chlorophyll (10.5g/kg) of dried sample; UT power (10W/L) yielded the highest L ∗ (51.5) and the lowest a ∗ (-9.3) value. Simultaneously, UT leads to a higher glass transition temperature (Tg), lower water activity and produces less sourness and bitterness of dried products. Ultra-sonication is an alternative to improve quality, flavor and energy consumption of barley grass in freeze drying. Copyright © 2017 Elsevier B.V. All rights reserved.

[A study of urine concentrating mechanism--a molecular biological approach].

PubMed

Marumo, F

1994-07-01

Human urine can be concentrated up to four times higher than that of the plasma. Urine concentrating mechanism has attracted for a long time. However, studies in the field are now picking up momentum due to recent breakthrough discoveries using molecular biology techniques. Vasopressin-regulated water channel in the apical membrane of the collecting duct and water channel in the basolateral side of the membrane were cloned. cloned. Osmolality-dependent chloride channel in the thin ascending limb of Henle was also cloned. In addition, vasopressin-regulated urea transporter was found in the collecting duct. These newly discovered channels and transporter should be playing important physiological roles in urine concentrating mechanism. Furthermore, recent findings on osmolytes and their transporters also add to the list of urine concentrating mechanisms.

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

Bonner, H.W.; Buffington, C.K.; Leslie, S.W.

Following a 25 ..mu..Ci/kg i/p injection, /sup 45/Ca/sup + +/ activity from the mitochondria and fragmented sarcoplasmic reticulum (FSR) of the superficial rectus femoris (FG-fibers) and combined soleus muscle (SO-fibers) of trained (T, N = 9) and untrained (UT, N = 8) male Wistar rats was determined. The FG mitochondrial /sup 45/Ca/sup + +/ activity from rested animals was 3.9 (T) and 5.3 (UT) times greater than the FSR from this muscle group while the SO-mitochondrial /sup 45/Ca/sup + +/ activity was 13.2 (T) and 20.5 (UT) times greater when compared with the respective SO-FSR (p less than 0.01). Themore » mitochondrial /sup 45/Ca/sup + +/ content of the SO-fibers from rested animals was 58% UT, (p less than 0.01) and 148% (T, p less than 0.001) greater than that of the FG mitochondria. After 20 to 26 weeks of exercise training the SO-mitochondrial /sup 45/Ca/sup + +/ content of the rested-T animals was approximately 18% lower (p less than 0.05) while the T-FG-mitochondrial /sup 45/Ca/sup + +/ content was 48% less than that of UT animals (p less than 0.01) with a concomitant 28% greater /sup 45/Ca/sup + +/ activity in SO-FSR for the T-group as compared to UT (p less than 0.01). Following a rapidly exhaustive treadmill run the mitochondrial /sup 45/Ca/sup + +/ content in the UT group was depressed by 21% in SO-fibers and 37% in FG-fibers (p less than 0.01) with no changes occurring in the T-group. Exhaustion produced no significant changes in the /sup 45/Ca/sup + +/ activity of the FSR from either group of animals.« less

Urea retranslocation from senescing Arabidopsis leaves is promoted by DUR3-mediated urea retrieval from leaf apoplast

PubMed Central

Bohner, Anne; Kojima, Soichi; Hajirezaei, Mohammad; Melzer, Michael; von Wirén, Nicolaus

2015-01-01

In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short-lived nitrogen (N) catabolite serving urease-mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels showed a parallel increase with senescence markers like ORE1 in a plant age- and leaf age-dependent manner. Deletion of DUR3 decreased urea accumulation in leaves, whereas the fraction of urea lost to the leaf apoplast was enhanced. Under natural and N deficiency-induced senescence DUR3 promoter activity was highest in the vasculature, but was also found in surrounding bundle sheath and mesophyll cells. An analysis of petiole exudates from wild-type leaves revealed that N from urea accounted for >13% of amino acid N. Urea export from senescent leaves further increased in ureG-2 deletion mutants lacking urease activity. In the dur3 ureG double insertion line the absence of DUR3 reduced urea export from leaf petioles. These results indicate that urea can serve as an early metabolic marker for leaf senescence, and that DUR3-mediated urea retrieval contributes to the retranslocation of N from urea during leaf senescence. PMID:25440717

Improving a Bimanual Motor Skill Through Unimanual Training

PubMed Central

Hayashi, Takuji; Nozaki, Daichi

2016-01-01

When we learn a bimanual motor skill (e.g., rowing a boat), we often break it down into unimanual practices (e.g., a rowing drill with the left or right arm). Such unimanual practice is thought to be useful for learning bimanual motor skills efficiently because the learner can concentrate on learning to perform a simpler component. However, it is not so straightforward to assume that unimanual training (UT) improves bimanual performance. We have previously demonstrated that motor memories for reaching movements consist of three different parts: unimanual-specific, bimanual-specific, and overlapping parts. According to this scheme, UT appears to be less effective, as its training effect is only partially transferred to the same limb for bimanual movement. In the present study, counter-intuitively, we demonstrate that, even after the bimanual skill is almost fully learned by means of bimanual training (BT), additional UT could further improve bimanual skill. We hypothesized that this effect occurs because UT increases the memory content in the overlapping part, which might contribute to an increase in the memory for bimanual movement. To test this hypothesis, we examined whether the UT performed after sufficient BT could improve the bimanual performance. Participants practiced performing bimanual reaching movements (BM) in the presence of a novel force-field imposed only on their left arm. As an index for the motor performance, we used the error-clamp method (i.e., after-effect of the left arm) to evaluate the force output to compensate for the force-field during the reaching movement. After sufficient BT, the training effect reached a plateau. However, UT performed subsequently improved the bimanual performance significantly. In contrast, when the same amount of BT was continued, the bimanual performance remained unchanged, highlighting the beneficial effect of UT on bimanual performance. Considering memory structure, we also expected that BT could improve unimanual performance, which was confirmed by another experiment. These results provide a new interpretation of why UT was useful for improving a bimanual skill, and propose a practical strategy for enhancing performance by performing training in various contexts. PMID:27471452

Utilization of dietary urea in rainbow trout.

PubMed

Kaushik, S J; Dabrowski, K R; Dabrowska, H; Olah, E; Luquet, P

1983-01-01

Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3% of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high (greater than 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 +/- 10.2 micrograms/ml) after a meal in the control fish and respectively 6 h (83.4 +/- 18.4 micrograms/ml) and 8 h (250.3 +/- 96.1 micrograms/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7-9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3% urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy demands.

Ammonia and greenhouse gas emissions from a subtropical wheat field under different nitrogen fertilization strategies.

PubMed

Liu, Shuai; Wang, Jim J; Tian, Zhou; Wang, Xudong; Harrison, Stephen

2017-07-01

Minimizing soil ammonia (NH 3 ) and nitrous oxide (N 2 O) emission factors (EFs) has significant implications in regional air quality and greenhouse gas (GHG) emissions besides nitrogen (N) nutrient loss. The aim of this study was to investigate the impacts of different N fertilizer treatments of conventional urea, polymer-coated urea, ammonia sulfate, urease inhibitor (NBPT, N-(n-butyl) thiophosphoric triamide)-treated urea, and nitrification inhibitor (DCD, dicyandiamide)-treated urea on emissions of NH 3 and GHGs from subtropical wheat cultivation. A field study was established in a Cancienne silt loam soil. During growth season, NH 3 emission following N fertilization was characterized using active chamber method whereas GHG emissions of N 2 O, carbon dioxide (CO 2 ), and methane (CH 4 ) were by passive chamber method. The results showed that coated urea exhibited the largest reduction (49%) in the EF of NH 3 -N followed by NBPT-treated urea (39%) and DCD-treated urea (24%) over conventional urea, whereas DCD-treated urea had the greatest suppression on N 2 O-N (87%) followed by coated urea (76%) and NBPT-treated urea (69%). Split fertilization of ammonium sulfate-urea significantly lowered both NH 3 -N and N 2 O-N EF values but split urea treatment had no impact over one-time application of urea. Both NBPT and DCD-treated urea treatments lowered CO 2 -C flux but had no effect on CH 4 -C flux. Overall, application of coated urea or urea with NPBT or DCD could be used as a mitigation strategy for reducing NH 3 and N 2 O emissions in subtropical wheat production in Southern USA. Copyright © 2017. Published by Elsevier B.V.

Influence of ultrasound and diamond burs treatments on microtensile bond strength.

PubMed

Conde, Alexandre; Mainieri, Vivian; Mota, Eduardo Goncalves; Oshima, Hugo Mitsuo

2012-01-01

To compare surface treatments with CVDentUS ultrasound tips (UT) and KGSorensen diamond burs (DB) on etched (e) and non-etched (n/e) dentin. The microtensile bond strength (μTBS) was measured and fractography was assessed by scanning electron microscope (SEM). Sixteen molars were divided into four groups of four teeth each according to treatment (DB-n/e; DB-e; UT-n/e; UT-e). The teeth were restored, sectioned into samples for μTBS (n=40) and tested on a EMIC DL-2000 universal machine (0.5 mm/min) and analyzed by SEM for fracture classification. For analysis of the data on μTBS, the two-way ANOVA, using treatment and acid etching as fixed factor, and the Tukey test were used (α=0.05). To failures classification in cohesive in dentin (CD); cohesive in composite resin (CC); cohesive interfacial on base or top of hybrid layer (CBT); cohesive in adhesive (CA); mixed (M); interfacial on smear layer (S) the Fisher's exact test (α=0.05) was performed. The mean values of μTBS (in MPa) in the different groups were as follows: UT-e: 45.31 ± 8.16; DB-e: 34.04 ± 9.29; UT-n/e: 15.17 ± 3.71; and DB-n/e: 9.86 ± 3.80. On analysis of the SEM micrographs, the DB-n/e group showed total obstruction of dentinal tubules; the UT-n/e group showed partial desobstruction of dentinal tubules and irregular surface; the DB-e group showed complete desobstruction of dentinal tubules; and the UT-e group showed complete desobstruction of dentinal tubules and irregular surface. The combination of ultrasound treatment and acid etching provides high values of μTBS. An association exists between CA/CC failures and the UT method, CBT failure and the DB method, CBT/CC failures and etching, S failure and non-etching.

75 FR 58433 - Notice of Inventory Completion: Brigham Young University, Museum of Peoples and Cultures, Provo, UT

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-24

... University, Museum of Peoples and Cultures, Provo, UT AGENCY: National Park Service, Interior. ACTION: Notice... objects in the possession of the Brigham Young University, Museum of Peoples and Cultures, Provo, UT. The..., 25 U.S.C. 3003(d)(3). The determinations in this notice are the sole responsibility of the museum...

The transverse technique; a complementary approach to the measurement of first-trimester uterine artery Doppler.

PubMed

Drouin, Olivier; Johnson, Jo-Ann; Chaemsaithong, Piya; Metcalfe, Amy; Huber, Janie; Schwarzenberger, Jill; Winters, Erin; Stavness, Lesley; Tse, Ada W T; Lu, Jing; Lim, Wan Teng; Leung, Tak Yeung; Bujold, Emmanuel; Sahota, Daljit; Poon, Liona C

2017-10-04

The objectives of this study were to 1) define the protocol for the first-trimester assessment of the uterine artery pulsatility index (UtA-PI) using the new transverse technique, 2) evaluate UtA-PI measured by the transverse approach versus that obtained by the conventional sagittal approach, and 3) determine if accelerated onsite training (both methods) of inexperienced sonographers can achieve reproducible UtA-PI measurements compared to that measured by an experienced sonographer. The study consists of 2 parts conducted in 2 centers (Part 1, Calgary, Canada and Part 2, Hong Kong). Part 1 Prospective observational study of women with singleton pregnancies between 11-13+6 weeks' gestation. UtA-PI measurements were performed using the 2 techniques (4 sonographers trained in both methods, 10 cases each) and measurement indices (PI), time required and subjective difficulty to obtain satisfactory measurements were compared. One sample t-test and Wilcoxon rank sign test was used when appropriate. Bland-Altman difference plots were used to assess measurement agreement, and intra-class correlation (ICC) was used to evaluate measurement reliability. A target plot was used to assess measures of central tendency and dispersion. Part 2 One experienced and three inexperienced sonographers prospectively measured the UtA-PI at 11-13+6 weeks' gestation in two groups of women (42 and 35, respectively), with singleton pregnancies using both approaches. Inexperienced sonographers underwent accelerated on-site training by the experienced sonographer. Measurement approach and sonographer order were on a random basis. ICC, Bland-Altman and Passing-Bablok analyses were performed to assess measurement agreement, reliability and effect of accelerated training. Part 1 We observed no difference in the mean time to acquire the measurements (Sagittal: 118 seconds vs Transverse: 106 seconds, p=0.38). The 4 sonographers reported the transverse technique was subjectively easier to perform (p=0.04). The bias (95% LOA) and the ICC between sagittal and transverse measurements was -0.05 (-0.48 to 0.37) and 0.94 for the mean UtA-PIs respectively. Measurements obtained using the transverse technique after correcting for gestation were significantly closer to the expected distribution than the sagittal technique. Part 2 There were no significant differences in the median UtA-PI measurements using the different approaches for both experienced and inexperienced sonographers (p>0.05 for all sonographers). Mean UtA-PI measurement reliability between approaches was high for the experienced (ICC=0.92) and inexperienced sonographers (ICC>0.81). UtA-PI measurement approaches did not deviate from linearity whilst biases ranged from -0.10 to 0.07. Median time required was similar (sagittal vs. transverse: 56.11 sec vs. 49.29 sec; p=0.054). This novel transverse approach for the measurement of UtA-PI in the first-trimester appears comparable to the sagittal approach and can be used in first-trimester preeclampsia screening. Providing accelerated onsite training can be helpful to improve UtA-PI measurement reliability and could potentially facilitate the broad implementation of first-trimester preeclampsia screening. This article is protected by copyright. All rights reserved.

Plasma membrane transporters for arginine.

PubMed

Closs, Ellen I; Simon, Alexandra; Vékony, Nicole; Rotmann, Alexander

2004-10-01

The supply of arginine may become rate limiting for enzymatic reactions that use this semiessential amino acid as a substrate (e.g., nitric oxide, agmatine, creatine, and urea synthesis), particularly under conditions of high demand such as growth, sepsis, or wound healing. In addition, arginine acts as a signaling molecule that regulates essential cellular functions such as protein synthesis, apoptosis, and growth. In the past decade, a number of carrier proteins for amino acids have been identified on the molecular level. They belong to different gene families, exhibit overlapping but distinctive substrate specificities, and can further be distinguished by their requirement for the cotransport or countertransport of inorganic ions. A number of these transporters function as exchangers rather than uniporters. Uptake of amino acids by these transporters therefore depends largely on the intracellular substrate composition. Hence, there is a complex crosstalk between transporters for cationic and neutral amino acids as well as for peptides. This article briefly reviews current knowledge regarding mammalian plasma membrane transporters that accept arginine as a substrate.

Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes.

PubMed

Omar, Latifah; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad

2015-01-01

Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-) losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 (+) and NO3 (-) release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 (-) leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 (+) retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 (+) and NO3 (-) release from urea.

Evaluation of carbon dioxide emission factor from urea during rice cropping season: A case study in Korean paddy soil

NASA Astrophysics Data System (ADS)

Kim, Gil Won; Jeong, Seung Tak; Kim, Gun Yeob; Kim, Pil Joo; Kim, Sang Yoon

2016-08-01

Fertilization with urea can lead to a loss of carbon dioxide (CO2) that was fixed during the industrial production process. The extent of atmospheric CO2 removal from urea manufacturing was estimated by the Industrial Processes and Product Use sector (IPPU sector). On its basis, the Intergovernmental Panel on Climate Change (IPCC) has proposed a value of 0.2 Mg C per Mg urea (available in 2006 revised IPCC guidelines for greenhouse gas inventories), which is the mass fractions of C in urea, as the CO2 emission coefficient from urea for the agricultural sector. Notably, due to the possibility of bicarbonate leaching to waters, all C in urea might not get released as CO2 to the atmosphere. Hence, in order to provide an accurate value of the CO2 emission coefficient from applied urea in the rice ecosystem, the CO2 emission factors were characterized under different levels of 13C-urea applied paddy field in the current study. The total CO2 fluxes and rice grain yields increased significantly with increasing urea application (110-130 kg N ha-1) and thereafter, decreased. However, with increasing 13C-urea application, a significant and proportional increase of the 13CO2sbnd C emissions from 13C-urea was also observed. From the relationships between urea application levels and 13CO2sbnd C fluxes from 13C-urea, the CO2sbnd C emission factor from urea was estimated to range between 0.0143 and 0.0156 Mg C per Mg urea. Thus, the CO2sbnd C emission factor of this study is less than that of the value proposed by IPCC. Therefore, for the first time, we propose to revise the current IPCC guideline value of CO2sbnd C emission factor from urea as 0.0143-0.0156 Mg C per Mg urea for Korean paddy soils.

Exploring the Counteracting Mechanism of Trehalose on Urea Conferred Protein Denaturation: A Molecular Dynamics Simulation Study.

PubMed

Paul, Subrata; Paul, Sandip

2015-07-30

To provide the underlying mechanism of the inhibiting effect of trehalose on the urea denatured protein, we perform classical molecular dynamics simulations of N-methylacetamide (NMA) in aqueous urea and/or trehalose solution. The site-site radial distribution functions and hydrogen bond properties indicate in binary urea solution the replacement of NMA-water hydrogen bonds by NMA-urea hydrogen bonds. On the other hand, in ternary urea and trehalose solution, trehalose does not replace the NMA-urea hydrogen bonds significantly; rather, it forms hydrogen bonds with the NMA molecule. The calculation of a preferential interaction parameter shows that, at the NMA surface, trehalose molecules are preferred and the preference for urea decreases slightly in ternary solution with respect to the binary solution. The exclusion of urea molecules in the ternary urea-NMA-trehalose system causes alleviation in van der Waals interaction energy between urea and NMA molecules. Our findings also reveal the following: (a) trehalose and urea induced second shell collapse of water structure, (b) a reduction in the mean trehalose cluster size in ternary solution, and (c) slowing down of translational motion of solution species in the presence of osmolytes. Implications of these results for the molecular explanations of the counteracting mechanism of trehalose on urea induced protein denaturation are discussed.

Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.

PubMed

Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

2011-08-01

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

NASA Astrophysics Data System (ADS)

Sharma, S.; Galav, P.; Dashora, N.; Pandey, R.

2011-06-01

Response of low latitude ionosphere to the geomagnetic storm of 15 May 2005 has been studied using total electron content (TEC) data, obtained from three GPS stations namely, Yibal, Udaipur and Kunming situated near the northern crest of equatorial ionization anomaly at different longitudes. Solar wind parameters, north-south component of the interplanetary magnetic field (IMF Bz) and AE index data have been used to infer the strength of the geomagnetic storm. A large value of eastward interplanetary electric field at 06:15 UT, during the time of maximum southward IMF Bz has been used to infer the transmission of an eastward prompt penetration electric field (PPEF) which resulted in a peak in TEC at 07:45 UT due to the local uplift of plasma in the low latitudes near the anomaly crest over a wide range of longitudes. Wave-like modulations superposed over the second enhancement in TEC between 09:15 UT to 10:30 UT have been observed at all the three stations. The second enhancement in TEC along with the modulations of up to 5 TECU have been attributed to the combined effect of super plasma fountain and traveling atmospheric disturbances (TAD). Observed large enhancements in TEC are a cause of concern for satellite based navigation and ground positioning. Increased [O/N2] ratio between 09:15 UT to 10:15 UT when modulations in TEC have been also observed, confirms the presence of TADs over a wide range of longitudes.

Urea immunoliposome inhibits human vascular endothelial cell proliferation for hemangioma treatment

PubMed Central

2013-01-01

Background Urea injection has been used in hemangioma treatment as sclerotherapy. It shrinks vascular endothelial cells and induces degeneration, necrosis, and fibrosis. However, this treatment still has disadvantages, such as lacking targeting and difficulty in controlling the urea dosage. Thus, we designed a urea immunoliposome to improve the efficiency of treatment. Methods The urea liposome was prepared by reverse phase evaporation. Furthermore, the urea immunoliposome was generated by coupling the urea liposome with a vascular endothelial growth factor receptor (VEGFR) monoclonal antibody using the glutaraldehyde cross-linking method. The influence of the urea immunoliposome on cultured human hemangioma vascular endothelial cells was observed preliminarily. Results Urea immunoliposomes showed typical liposome morphology under a transmission electron microscope, with an encapsulation percentage of 54.4% and a coupling rate of 36.84% for anti-VEGFR. Treatment with the urea immunoliposome significantly inhibited the proliferation of hemangioma vascular endothelial cells (HVECs) in a time- and dose-dependent manner. Conclusions The urea immunoliposome that we developed distinctly and persistently inhibited the proliferation of HVECs and is expected to be used in clinical hemangioma treatment. PMID:24266957

VizieR Online Data Catalog: Venus mesosphere ALMA observations (Piccialli+, 2017)

NASA Astrophysics Data System (ADS)

Piccialli, A.; Moreno, R.; Encrenaz, T.; Fouchet, T.; Lellouch, E.; Widemann, T.

2017-07-01

Observations of Venus were obtained using the ALMA interferometer within the project labeled 2011.0.00136.S. We observed - with a single receiver tuning setup - the CO, SO, SO2 and H2O rotational lines at frequencies of 345.795GHz, 346.528GHz, 346.652GHz and 335.395GHz, respectively. The spectral resolution (originally 61kHz) was binned to 0.35MHz in order to optimize the S/N. These observations were obtained on November 14, 2011, between 22:15 and 22:53 UT; on November 15, 2011, between 20:39 and 21:11 UT; on November 26, 2011, between 21:24 and 22:02 UT; and on November 27, 2011, between 21:07 and 21:58 UT. (23 data files).

Electromyographic analysis of the serratus anterior and trapezius muscles during push-ups on stable and unstable bases in subjects with scapular dyskinesis.

PubMed

Pirauá, André Luiz Torres; Pitangui, Ana Carolina Rodarti; Silva, Juliana Pereira; Pereira dos Passos, Muana Hiandra; Alves de Oliveira, Valéria Mayaly; Batista, Laísla da Silva Paixão; Cappato de Araújo, Rodrigo

2014-10-01

The present study was performed to assess the electromyographic activity of the scapular muscles during push-ups on a stable and unstable surface, in subjects with scapular dyskinesis. Muscle activation (upper trapezius [UT]; lower trapezius [LT]; upper serratus anterior [SA_5th]; lower serratus anterior [SA_7th]) and ratios (UT/LT; UT/SA_5th; UT/ SA_7th) levels were determined by surface EMG in 30 asymptomatic men with scapular dyskinesis, during push-up performed on a stable and unstable surface. Multivariate analysis of variance with repeated measures was used for statistical analyses. The unstable surface caused a decrease in the EMG activity of the serratus anterior and an increase in EMG activity of the trapezius (p=0.001). UT/SA_5th and UT/ SA_7th ratios were higher during unstable push-ups (p=0.001). The results suggest that, in individuals with scapular dyskinesis, there is increased EMG activity of the trapezius and decreased EMG activity of the serratus anterior in response to an unstable surface. These results suggest that the performance of the push up exercise on an unstable surface may be more favorable to produce higher levels of trapezius activation and lower levels of serratus anterior activation. However, if the goal of the exercise program is the strengthening of the SA muscle, it is suggested to perform the push up on a stable surface. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows.

PubMed

Spek, J W; Dijkstra, J; Bannink, A

2016-05-01

The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed to obtain insight in urea transfer characteristics within the mammary gland and from the mammary gland to blood plasma in dairy cows at various concentrations of plasma urea nitrogen (PUN; mg of N/dL) and MUN. Urea transfer from milk to blood plasma and urea transfer within the mammary gland itself was evaluated in a 4×4 Latin square design using 4 lactating multiparous Holstein-Friesian cows (milk production of 39.8±4.70kg/d and 90±3.9 d in milk). Treatments consisted of 4 primed continuous intravenous urea infusions of 0, 5, 10, and 15g of urea/h. Boluses of [(15)N(15)N]urea were injected in cistern milk at 20, 60, and 100 min before the 1700h milking. Milk was collected in portions of approximately 2 L at the 1700h milking. Milk samples were analyzed for urea and enrichment of (15)N-urea. Results from one cow were discarded because of leakage of milk from the teats after injection of boluses of [(15)N(15)N]urea. Increasing urea infusion rate linearly increased PUN from 11.4 (0g of urea/h) to 25.9mg/dL (15g of urea/h) and MUN from 10.3 (0g of urea/h) to 23.5 (15g of urea/h) mg of N/dL. The percentage of injected [(15)N(15)N]urea recovered from milk at the time of injection was not affected by urea infusion rate and varied between 65.1 and 73.0%, indicating that a substantial portion of injected [(15)N(15)N]urea was not accounted for by collected milk. The estimated fractional disappearance rate of (15)N-urea from milk to blood (Kurea; per hour) linearly increased from 0.429 (0g of urea/h) to 0.641 per hour (15g of urea/h). Cistern injected [(15)N(15)N]urea diffused within 20 min after injection toward alveoli milk. Calculations with the average Kurea estimated in this study show that 89% of an initial difference between PUN and MUN will have disappeared after 4 h. In conclusion, urea disappearance from milk in the mammary gland is substantial, as well as the intramammary urea exchange between cistern, duct, and alveoli milk. However, results have to be interpreted with caution given the lack of full recovery of dosed (15)N urea at time of injection. Information on Kurea is useful to quantify the effects of diurnal variation in PUN on MUN, which enhances the utility of MUN as an indicator for N excretion in urine. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Multi-point observations of Ion Dispersions near the Exterior Cusp with Cluster

NASA Astrophysics Data System (ADS)

Escoubet, C.-Philippe; Grison, Benjamin; Berchem, Jean; Trattner, Kralheinz; Pitout, Frederic; Richard, Robert; Taylor, Matt; Soucek, Jan; Laakso, Harri; Masson, Arnaud; Dunlop, Malcolm; Dandouras, Iannis; Reme, Henri; Fazakerley, Andrew; Daly, Patrick

2014-05-01

The exterior cusp is the most external region of the polar magnetosphere in direct contact with the plasma and the magnetic field from the solar wind. Unlike the rest of the magnetopause surface, the exterior cusp is a singular region with small and turbulent magnetic field and where large entry of plasma from solar origin takes place. The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process will take place equatorward (for IMF southward), poleward (for IMF northward) or on the dusk or dawn sides (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s and the density around 5 cm-3. The four Cluster spacecraft were still in the "magnetotail" configuration with two perfect tetrahedra of 2000 km around apogee and turning into an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions in the dispersions, we obtain an altitude of the sources of these ions between 14 and 20 RE. Using Tsyganenko model, these sources are located on the dusk flank, past the terminator. In addition, before entering the cusp, the magnetopause crossing was characterized by a large shear in By and bipolar plasma flows, suggesting that reconnection was taking place near the exterior cusp. We will discuss the extent of the reconnection line along the flank of the magnetopause based on these observations.

Joint NuSTAR and IRIS observation of a microflaring active region

NASA Astrophysics Data System (ADS)

Hannah, I. G.; Kleint, L.; Krucker, S.; Glesener, L.; Grefenstette, B.

2017-12-01

We present observations of a weakly microflaring active region observed in X-rays with NuSTAR, UV with IRIS and EUV with SDO/AIA. NuSTAR was pointed at this unnamed active region near the East limb between 23:27UT and 23:37UT 26-July-2016, finding mostly quiescent emission except for a small microflare about 23:35UT. The NuSTAR spectrum for the pre-microflare time (23:27UT to 23:34UT) is well fitted by a single thermal component of about 3MK and combined with SDO/AIA we can determine the differential emission measure (DEM), finding it, as expected, drops very sharply to higher temperatures. During the subsequent microflare, the increase in NuSTAR counts matches a little brightening loop observed with IRIS SJI 1400Å and SDO/AIA. Fortuitously the IRIS slit crosses this microflaring loop and we find an increased emission in Si IV 1394Å, Si IV 1403Å and O IV 1402Å but only average line widths and velocities. The NuSTAR microflare spectrum shows heating to higher temperatures and also allows us to investigate the energetics of this event.

Status and Prospects for Combined GPS LOD and VLBI UT1 Measurements

NASA Astrophysics Data System (ADS)

Senior, K.; Kouba, J.; Ray, J.

2010-01-01

A Kalman filter was developed to combine VLBI estimates of UT1-TAI with biased length of day (LOD) estimates from GPS. The VLBI results are the analyses of the NASA Goddard Space Flight Center group from 24-hr multi-station observing sessions several times per week and the nearly daily 1-hr single-baseline sessions. Daily GPS LOD estimates from the International GNSS Service (IGS) are combined with the VLBI UT1-TAI by modeling the natural excitation of LOD as the integral of a white noise process (i.e., as a random walk) and the UT1 variations as the integration of LOD, similar to the method described by Morabito et al. (1988). To account for GPS technique errors, which express themselves mostly as temporally correlated biases in the LOD measurements, a Gauss-Markov model has been added to assimilate the IGS data, together with a fortnightly sinusoidal term to capture errors in the IGS treatments of tidal effects. Evaluated against independent atmospheric and oceanic axial angular momentum (AAM + OAM) excitations and compared to other UT1/LOD combinations, ours performs best overall in terms of lowest RMS residual and highest correlation with (AAM + OAM) over sliding intervals down to 3 d. The IERS 05C04 and Bulletin A combinations show strong high-frequency smoothing and other problems. Until modified, the JPL SPACE series suffered in the high frequencies from not including any GPS-based LODs. We find, surprisingly, that further improvements are possible in the Kalman filter combination by selective rejection of some VLBI data. The best combined results are obtained by excluding all the 1-hr single-baseline UT1 data as well as those 24-hr UT1 measurements with formal errors greater than 5 μs (about 18% of the multi-baseline sessions). A rescaling of the VLBI formal errors, rather than rejection, was not an effective strategy. These results suggest that the UT1 errors of the 1-hr and weaker 24-hr VLBI sessions are non-Gaussian and more heterogeneous than expected, possibly due to the diversity of observing geometries used, other neglected systematic effects, or to the much shorter observational averaging interval of the single-baseline sessions. UT1 prediction services could benefit from better handling of VLBI inputs together with proper assimilation of IGS LOD products, including using the Ultra-rapid series that is updated four times daily with 15 hr delay.

Improving Ammonium and Nitrate Release from Urea Using Clinoptilolite Zeolite and Compost Produced from Agricultural Wastes

PubMed Central

Omar, Latifah; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

2015-01-01

Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 − leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 + and NO3 − release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 + and NO3 − losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 + and NO3 − release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 − leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 + retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 + and NO3 − release from urea. PMID:25793220

The variability and IRI2007-predictability of hmF2 over South Africa

NASA Astrophysics Data System (ADS)

Mbambo, M. C.; McKinnell, Lee-Anne; Habarulema, J. B.

2013-11-01

This paper presents an investigation into the variability and predictability of the maximum height of the ionospheric F2 layer, hmF2 over the South African region. Data from three South African stations, namely Madimbo (22.4°S, 26.5°E, dip angle: -61.47°), Grahamstown (33.3°S, 26.5°E, dip angle: -64.08°) and Louisvale (28.5°S, 21.2°E, dip angle: -65.44°) were used in this study. The results indicate that hmF2 shows a larger variability around midnight than during the daytime for all seasons. Monthly median hmF2 values were used in all cases and were compared with predictions from the IRI-2007 model, using the URSI (Union Radio-Scientifique Internationale) coefficient option. The analysis covers the diurnal and seasonal hourly hmF2 values for the selected months and time sectors e.g. January, July, April and October for 2003 and 2005. The time ranges between (03h00-23h00 UT; LT = UT + 2h) representing the local sunrise, midday, sunset and midnight hours. The time covers sunrise, midday, sunrise, and midnight hours (03-06h00 UT, 07-11h00 UT, sunrise 16-18h00 UT and 22-23h00 UT; LT = UT + 2h). The dependence of the results on solar activity levels was also investigated. The IRI-2007 predictions follow fairly well the diurnal and seasonal variation patterns of the observed hmF2 values at all the stations. However, the IRI-2007 model overestimates and underestimates the hmF2 value during different months for all the solar activity periods.

Characterization of the near-Earth Asteroid 2002 NY40

DTIC Science & Technology

2007-09-01

central wavelength for a given observation, it typically operates in two modes, a blue -wavelength mode that ranges from 4000–7000 Å and a red...wavelength mode that covers 6000–9000 Å. The blue mode currently operates with a long pass filter configuration blocking all wavelengths shorter than 4000 Å... blue spectra were taken from 9:10–9:54 UT and red spectra were taken from 10:59–11:25 UT. Additional red data were taken on the 18th from 8:41–9:17 UT

Cells for bioartificial liver devices: the human hepatoma-derived cell line C3A produces urea but does not detoxify ammonia.

PubMed

Mavri-Damelin, Demetra; Damelin, Leonard H; Eaton, Simon; Rees, Myrddin; Selden, Clare; Hodgson, Humphrey J F

2008-02-15

Extrahepatic bioartificial liver devices should provide an intact urea cycle to detoxify ammonia. The C3A cell line, a subclone of the hepatoma-derived HepG2 cell line, is currently used in this context as it produces urea, and this has been assumed to be reflective of ammonia detoxification via a functional urea cycle. However, based on our previous findings of perturbed urea-cycle function in the non-urea producing HepG2 cell line, we hypothesized that the urea produced by C3A cells was via a urea cycle-independent mechanism, namely, due to arginase II activity, and therefore would not detoxify ammonia. Urea was quantified using (15)N-ammonium chloride metabolic labelling with gas chromatography-mass spectrometry. Gene expression was determined by real-time reverse transcriptase-PCR, protein expression by western blotting, and functional activities with radiolabelling enzyme assays. Arginase inhibition studies used N(omega)-hydroxy-nor-L-arginine. Urea was detected in C3A conditioned medium; however, (15)N-ammonium chloride-labelling indicated that (15)N-ammonia was not incorporated into (15)N-labelled urea. Further, gene expression of two urea cycle genes, ornithine transcarbamylase and arginase I, were completely absent. In contrast, arginase II mRNA and protein was expressed at high levels in C3A cells and was inhibited by N(omega)-hydroxy-nor-L-arginine, which prevented urea production, thereby indicating a urea cycle-independent pathway. The urea cycle is non-functional in C3A cells, and their urea production is solely due to the presence of arginase II, which therefore cannot provide ammonia detoxification in a bioartificial liver system. This emphasizes the continued requirement for developing a component capable of a full repertoire of liver function. (c) 2007 Wiley Periodicals, Inc.

Simulated microgravity induce apoptosis and down-regulation of erythropoietin receptor of UT-7/EPO cells

NASA Astrophysics Data System (ADS)

Zou, Li-xue; Cui, Shao-yan; Zhong, Jian; Yi, Zong-chun; Sun, Yan; Fan, Yu-bo; Zhuang, Feng-yuan

2010-11-01

Hematopoietic progenitor cell proliferation can be alternated on either spaceflight or under simulated microgravity experiments on the ground; however, the underlying mechanism remains largely unknown. In the present study, we have demonstrated that exposure of human erythropoietin (EPO)-dependent leukemia cell line UT-7/EPO cells to conditions of simulated microgravity with a rotary culture instrument significantly inhibited the cellular proliferation rate. Adding higher concentrations of EPO to the culture medium failed to improve the inhibitory status. Cell apoptosis was detected by fluorescence staining of cell nuclei and a flow cytometry assay using Annexin V/PI double staining. This microgravity-induced apoptosis in UT-7/EPO cells could be blocked by a pancaspase inhibitor Z-VAD-FMK. Immunoblotting demonstrated that rotary culture resulted in a reduction of the expression of Bcl-xL, an anti-apoptotic protein, and the cleavage of caspase-3. Furthermore, rotary culture reduced surface localization and protein content, as well as the mRNA expression of erythropoietin receptor (EPOR) of UT-7/EPO. Take together, the findings indicated that simulated microgravity may induce mitochondrial related apoptosis of UT-7/EPO cell through depressing the EPO-EPOR pathway.

The Accuracy of Radio Interferometric Measurements of Earth Rotation

NASA Technical Reports Server (NTRS)

Eubanks, T. M.; Steppe, J. A.; Spieth, M. A.

1985-01-01

The accuracy of very long base interferometry earth rotation (UT1) measurements is examined by intercomparing TEMPO and POLARIS data for 1982 and the first half of 1983. None of these data are simultaneous, and so a proper intercomparison requires accounting for the scatter introduced by the rapid, unpredictable, UT1 variations driven by exchanges of angular momentum with the atmosphere. A statistical model of these variations, based on meteorological estimates of the Atmospheric Angular Momentum is derived, and the optimal linear (Kalman) smoother for this model is constructed. The scatter between smoothed and independent raw data is consistent with the residual formal errors, which do not depend upon the actual scatter of the UT1 data. This represents the first time that an accurate prediction of the scatter between UT1 data sets were possible.

Using Phased Array Ultrasonic Testing in Lieu of Radiography for Acceptance of Carbon Steel Piping Welds

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

Moran, Traci L.; Anderson, Michael T.; Cinson, Anthony D.

2014-08-01

The Pacific Northwest National Laboratory (PNNL) is conducting studies for the U.S. Nuclear Regulatory Commission (NRC) to assess the capability, effectiveness, and reliability of ultrasonic testing (UT) as a replacement method for radiographic testing (RT) for volumetric examination of nuclear power plant (NPP) components. This particular study focused on evaluating the use of UT on carbon steel plate welds. Welding fabrication flaws included a combination of planar and volumetric types, e.g., incomplete fusion, lack of penetration, cracks, porosity, and slag inclusions. The examinations were conducted using phased-array (PA) UT techniques applied primarily for detection and flaw type characterization. This papermore » will discuss the results of using UT in lieu of RT for detection and classification of fabrication flaws in carbon steel plate welds.« less

Final report of the safety assessment of Urea.

PubMed

2005-01-01

Although Urea is officially described as a buffering agent, humectant, and skin-conditioning agent-humectant for use in cosmetic products, there is a report stating that Urea also is used in cosmetics for its desquamating and antimicrobial action. In 2001, the Food and Drug Administration (FDA) reported that Urea was used in 239 formulations. Concentrations of use for Urea ranged from 0.01% to 10%. Urea is generally recognized as safe by FDA for the following uses: side-seam cements for food contact; an inhibitor or stabilizer in pesticide formulations and formulations applied to animals; internal sizing for paper and paperboard and surface sizing and coating of paper and paper board that contact water-in-oil dairy emulsions, low-moisture fats and oils, moist bakery products, dry solids with surface containing no free fats or oil, and dry solids with the surface of fat or oil; and to facilitate fermentation of wine. Urea is the end product of mammalian protein metabolism and the chief nitrogenous compound of urine. Urea concentrations in muscle, liver, and fetuses of rats increased after a subcutaneous injection of Urea. Urea diffused readily through the placenta and into other maternal and fetal organs. The half-life of Urea injected into rabbits was on the order of several hours, and the reutilization rate was 32.2% to 88.8%. Urea given to rats by a bolus injection or continuous infusion resulted in distribution to the following brain regions: frontal lobe, caudate nucleus, hippocampus, thalamus plus hypothalamus, pons and white matter (corpus callosum). The permeability constant after treatment with Urea of whole skin and the dermis of rabbits was 2.37 +/- 0.13 (x 10(6)) and 1.20 +/- 0.09 (x10(3)) cm/min, respectively. The absorption of Urea across normal and abraded human skin was 9.5% +/- 2.3% and 67.9% +/- 5.6%, respectively. Urea increased the skin penetration of other compounds, including hydrocortisone. No toxicity was observed for Urea at levels as high as 2000 mg/kg in acute oral studies using female rats or mice. No signs of toxicity were observed in male piglets dosed orally with up to 4 g/kg Urea for 5 days. Dogs dosed orally with 5 to 30 g/L Urea for 4 to 10 days had signs of toxicity, including weakness, anorexia, vomiting and retching, diarrhea and a decreased body temperature, which led to a deep torpor or coma. No significant microscopic changes were observed in the skin of male nude mice dermally exposed to 100% Urea for 24 h. No observable effect on fetal development was seen in rats and mice dosed orally with an aqueous solution of Urea (2000 mg/kg) on days 10 and 12 of gestation. The mean number of implants, live fetuses, percent fetal resorptions, mean fetal weight, and percent fetuses malformed were comparable to control group. A detergent containing 15% Urea was injected into pregnant ICR-JCl mice and dams and fetuses had no significant differences when compared to control animals. Urea given orally did not enhance the developmental toxicity of N-nitrosomethylurea. Female Sprague-Dawley rats injected in the uterine horn with 0.05 ml Urea on day 3 (preimplantation) or on day 7 (post implantation) exhibited no maternal mortality or morbidity; a dose-dependent reduction in embryo survival was seen with preimplantation treatment. Urea injected intra-amniotically induces mid-trimester abortions in humans. Urea was not genotoxic in several bacterial and mammalian assays; although in assays where Urea was used at a high concentration, genotoxicity was found, many in in vitro assays. Urea is commonly used in studies of DNA because it causes uncoiling of DNA molecules. Urea was not carcinogenic in Fisher 344 rats or C57B1/6 mice fed diets containing up to 4.5% Urea. Exposure of normal human skin to 60% Urea produced no significant irritation in one study, but 5% Urea was slightly irritating and 20% Urea was irritating in other reports. Burning sensations are the most frequently reported effect of Urea used alone or with other agents in treatment of diseased skin. Overall, there are few reports of sensitization among the many clinical studies that report use of Urea in treatment of diseased skin. The Cosmetic Ingredient Review (CIR) Expert Panel determined the data provided in this report to be sufficient to assess the safety of Urea. The Panel did note that Urea can cause uncoiling of DNA, a property used in many DNA studies, but concluded that this in vitro activity is not linked to any in vivo genotoxic activity. Although noting that formulators should be aware that Urea can increase the percutaneous absorption of other chemicals, the CIR Expert Panel concluded that Urea is safe as used in cosmetic products.

ABCC1 is related to the protection of the distal nephron against hyperosmolality and high sodium environment: possible implications for cancer chemotherapy.

PubMed

Fonseca, Leonardo M; Alvarez, Adriana B; Rodrigues, Rachel C; Santos, Diego H F; Lopes, Anibal G; Capella, Marcia A M

2013-01-01

Glutathione (GSH) plays an important role in protecting cells against oxidative damage. ABCC1 protein transports GSH. Although this protein is largely studied in cancer, due to multidrug resistance phenotype, its role in the tubular cells of the kidney is unknown. The goal of this study was to find out whether ABCC1 has a role in protecting cells from the distal nephron against the stress caused by high medullar osmolality. MA104 cells were treated with high concentrations of sodium chloride, urea, or both to raise the osmolality of the culture medium. Cell viability was accessed by MTT and trypan blue assays. ABCC1 expression and extrusion of carboxi-fluorescein (CF), a fluorescent ABCC1 substrate, were measured by flow cytometry. Incubation of MA104 cells in a high sodium concentration medium resulted in changes in cell granularity and altered expression and activity of ABCC1. Urea did not alter ABCC1 expression or activity, but reversed the observed NaCl effects. High sodium concentrations also had a negative effect on cell viability and urea also protected cells against this effect. Our findings demonstrate that ABCC1 plays a significant role in the protection of kidney epithelial cells against the stress caused by high sodium environment present in renal medulla.

In vivo urea cycle flux distinguishes and correlates with phenotypic severity in disorders of the urea cycle

PubMed Central

Lee, Brendan; Yu, Hong; Jahoor, Farook; O'Brien, William; Beaudet, Arthur L.; Reeds, Peter

2000-01-01

Urea cycle disorders are a group of inborn errors of hepatic metabolism that result in often life-threatening hyperammonemia and hyperglutaminemia. Clinical and laboratory diagnosis of partial deficiencies during asymptomatic periods is difficult, and correlation of phenotypic severity with either genotype and/or in vitro enzyme activity is often imprecise. We hypothesized that stable isotopically determined in vivo rates of total body urea synthesis and urea cycle-specific nitrogen flux would correlate with both phenotypic severity and carrier status in patients with a variety of different enzymatic deficiencies of the urea cycle. We studied control subjects, patients, and their relatives with different enzymatic deficiencies affecting the urea cycle while consuming a low protein diet. On a separate occasion the subjects either received a higher protein intake or were treated with an alternative route medication sodium phenylacetate/benzoate (Ucephan), or oral arginine supplementation. Total urea synthesis from all nitrogen sources was determined from [18O]urea labeling, and the utilization of peripheral nitrogen was estimated from the relative isotopic enrichments of [15N]urea and [15N]glutamine during i.v. co-infusions of [5-(amide)15N]glutamine and [18O]urea. The ratio of the isotopic enrichments of 15N-urea/15N-glutamine distinguished normal control subjects (ratio = 0.42 ± 0.06) from urea cycle patients with late (0.17 ± 0.03) and neonatal (0.003 ± 0.007) presentations irrespective of enzymatic deficiency. This index of urea cycle activity also distinguished asymptomatic heterozygous carriers of argininosuccinate synthetase deficiency (0.22 ± 0.03), argininosuccinate lyase deficiency (0.35 ± 0.11), and partial ornithine transcarbamylase deficiency (0.26 ± 0.06) from normal controls. Administration of Ucephan lowered, and arginine increased, urea synthesis to the degree predicted from their respective rates of metabolism. The 15N-urea/15N-glutamine ratio is a sensitive index of in vivo urea cycle activity and correlates with clinical severity. Urea synthesis is altered by alternative route medications and arginine supplementation to the degree that is to be expected from theory. This stable isotope protocol provides a sensitive tool for evaluating the efficacy of therapeutic modalities and acts as an aid to the diagnosis and management of urea cycle patients. PMID:10869432

Extracellular vesicles from human liver stem cells restore argininosuccinate synthase deficiency.

PubMed

Herrera Sanchez, Maria Beatriz; Previdi, Sara; Bruno, Stefania; Fonsato, Valentina; Deregibus, Maria Chiara; Kholia, Sharad; Petrillo, Sara; Tolosano, Emanuela; Critelli, Rossana; Spada, Marco; Romagnoli, Renato; Salizzoni, Mauro; Tetta, Ciro; Camussi, Giovanni

2017-07-27

Argininosuccinate synthase (ASS)1 is a urea cycle enzyme that catalyzes the conversion of citrulline and aspartate to argininosuccinate. Mutations in the ASS1 gene cause citrullinemia type I, a rare autosomal recessive disorder characterized by neonatal hyperammonemia, elevated citrulline levels, and early neonatal death. Treatment for this disease is currently restricted to liver transplantation; however, due to limited organ availability, substitute therapies are required. Recently, extracellular vesicles (EVs) have been reported to act as intercellular transporters carrying genetic information responsible for cell reprogramming. In previous studies, we isolated a population of stem cell-like cells known as human liver stem cells (HLSCs) from healthy liver tissue. Moreover, EVs derived from HLSCs were reported to exhibit regenerative effects on the liver parenchyma in models of acute liver injury. The aim of this study was to evaluate whether EVs derived from normal HLSCs restored ASS1 enzymatic activity and urea production in hepatocytes differentiated from HLSCs derived from a patient with type I citrullinemia. HLSCs were isolated from the liver of a patient with type I citrullinemia (ASS1-HLSCs) and characterized by fluorescence-activated cell sorting (FACS), immunofluorescence, and DNA sequencing analysis. Furthermore, their differentiation capabilities in vitro were also assessed. Hepatocytes differentiated from ASS1-HLSCs were evaluated by the production of urea and ASS enzymatic activity. EVs derived from normal HLSCs were purified by differential ultracentrifugation followed by floating density gradient. The EV content was analyzed to identify the presence of ASS1 protein, mRNA, and ASS1 gene. In order to obtain ASS1-depleted EVs, a knockdown of the ASS1 gene in HLSCs was performed followed by EV isolation from these cells. Treating ASS1-HLSCs with EVs from HLSCs restored both ASS1 activity and urea production mainly through the transfer of ASS1 enzyme and mRNA. In fact, EVs from ASS1-knockdown HLSCs contained low amounts of ASS1 mRNA and protein, and were unable to restore urea production in hepatocytes differentiated from ASS1-HLSCs. Collectively, these results suggest that EVs derived from normal HLSCs may compensate the loss of ASS1 enzyme activity in hepatocytes differentiated from ASS1-HLSCs.

CRTS-II Detection of Increased Optical Activity from CTA 102

NASA Astrophysics Data System (ADS)

Djorgovski, S. G.; Drake, A. J.; Mahabal, A. A.; Graham, M. J.; Christensen, E.; Larson, S. M.

2017-12-01

We report the detection of significant optical brightening of FSRQ CTA 102 by CRTS-II on 2017 Dec. 8.15 UT. At that time CTA 102 was seen to have risen approximately 1.4 mags (to V_CSS = 14.15) compared with previous observations taken on 2017 Nov. 23 UT. Additional survey observations taken on 2017 Dec. 15 UT show CTA 102 at V_CSS = 14.05.

A prospective randomized comparison of unsedated ultrathin versus standard esophagogastroduodenoscopy in routine outpatient gastroenterology practice: does it work better through the nose?

PubMed

Birkner, B; Fritz, N; Schatke, W; Hasford, J

2003-08-01

In an outpatient gastroenterological practice setting, highly effective diagnostic procedures and patient satisfaction play an important role. Ultrathin endoscopy in unsedated patients has been shown to be more cost-effective and time-efficient in comparison with standard endoscopy. A prospective randomized study was carried out in unsedated patients to compare performance, feasibility, safety, and patient tolerance between ultrathin transnasal (UT), ultrathin oral (UO), and standard (SO) esophagogastroduodenoscopy (EGD). A total of 200 of 600 eligible patients consented to participate in the study, and were randomly assigned to undergo UT, UO, or SO. Patients reported their tolerance of the procedure (anxiety, pain, gagging, and overall satisfaction; Likert scale 1-10), and the endoscopists reported the effectiveness of the procedure (handling, picture quality, and overall performance; Likert scale 1-10). Statistics were calculated using the Kruskal-Wallis test. After randomization, 65, 67, and 68 patients were allocated to the UT, UO, and SO groups, respectively. Failure to achieve complete EGD by the intended route occurred in 14 patients (22 %) in the UT group. Compared to the SO group, patients in the UT and UO groups rated anxiety before the procedure as being more intense - median score (10 % quantile estimate; 90 % quantile estimate): UT, 2.0 (1.0; 4.0); UO, 2.0 (1.0; 4.0); SO, 0.0 (0.0; 2.0); p < 0.0001), whereas SO patients experienced a higher level of anxiety during the procedure ( P < 0.0001). Pain during insertion of the endoscope was the least intense in the UO group: UT, 2.0 (1.0; 5.0); UO, 1.0 (1.0; 3.0); SO, 2.0 (1.0; 4.0); P < 0.001). Gagging during insertion was more pronounced in the UO group: UT, 2.0 (1.0; 4.0); UO, 3.0 (1.0; 7.0); SO, 2.0 (1.0; 5.0); P < 0.01). The patients' score for the overall assessment was better in the SO group ( P < 0.0001). The endoscopists' overall assessment for ultrathin EGD was poorer than for standard EGD: UT, 3.0 (2.0; 5.0); UO, 3.0 (2.0; 5.0); SO, 2.0 (1.0; 3.0); P < 0.0001). Ultrathin endoscopy through both the transnasal and oral routes has limited use in routine outpatient practice. Techniques for reducing pain and gagging may improve patient tolerance. Further technical improvements are needed to allow routine implementation.

X-ray Pulsations from AXP 1E 1547-5407 Detected with RXTE

NASA Astrophysics Data System (ADS)

Dib, R.; Kaspi, V. M.; Gavriil, F. P.; Woods, P. M.

2008-10-01

We observed AXP 1E 1547-5407 which is currently in outburst (see ATELs #1756, #1761, #1763) with RXTE on October 4 (4 ks), and 6 (1.4 ks, 1.6 ks). The 2-20 keV pulse profile of these observations (October 04 UT 21:51:04, October 06 UT 01:46:04, and October 06 UT 23:31:04) shows a single broad pulse that is qualitatively similar to that reported in Halpern et al. (2008, ApJ, 676, 1178), though there is a possible hint of additional peaks.

Modulation of cadmium-induced phytotoxicity in Cabomba caroliniana by urea involves photosynthetic metabolism and antioxidant status.

PubMed

Huang, Wenmin; Shao, Hui; Zhou, Sining; Zhou, Qin; Li, Wei; Xing, Wei

2017-10-01

Urea is a widespread organic pollutant, which can be a nitrogen source, playing different roles in the growth of submerged macrophytes depending on concentrations, while high cadmium (Cd) concentrations are often toxic to macrophytes. In order to evaluate the combined effect of urea and Cd on a submerged macrophyte, Cabomba caroliniana, the morphological and physiological responses of C. caroliniana in the presence of urea and Cd were studied. The results showed that high concentrations of urea (400mgL -1 ) and Cd (500µmolL -1 ) had negative effects on C. caroliniana. There were strong visible symptoms of toxicity after 4 days of exposure under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. In addition, 400mgL -1 urea and Cd had adverse effects on C. caroliniana's pigment system. Significant losses in chlorophyll fluorescence and photosynthetic rates, as well as Rubisco activity were also observed under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. 400mgL -1 urea markedly enhanced Cd toxicity in C. caroliniana, reflected by a sharp decrease in photosynthetic activity and more visible toxicity symptoms. The results of thiobarbituric acid reactive substances (TBARS) pointed to extreme oxidative stress in C. caroliniana induced under Cd or 400mgL -1 urea exposure. Exogenous ascorbate (AsA) protected C. caroliniana from adverse damage in 400mgL -1 urea, which further corroborated the oxidative stress claim under 400mgL -1 urea. However, results also demonstrated that lower urea concentration (10mgL -1 ) alleviated Cd-induced phytotoxicity by stimulating chlorophyll synthesis and photosynthetic activity, as well as activating the activity of catalase (CAT) and glutathione-S-transferase (GST), which may explain the alleviating effect of urea on C. caroliniana under Cd stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

PubMed

Sobiecka, Danuta; Waniewski, Jacek; Weryński, Andrzej; Lindholm, Bengt

2004-01-01

Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded unrealistic values of fluid transport parameters that differed from those estimated by models OS and P. The K(BD) values for small solutes were significantly different among the groups, and did not correlate with fluid transport parameters for model OS. The difference in fluid transport between the different transport groups was due only to the differences in the rate of disappearance of the overall osmotic pressure of the dialysate, which was a combined result of the transport rate of glucose and other small solutes. Although the glucose gradient is the major factor influencing ultrafiltration rate, other solutes, such as urea, are also of importance. The counteractive effect of plasma small solutes on transcapillary ultrafiltration was found to be especially notable in low transport patients. Thus, glucose gradient alone should not be considered the only force that shapes the ultrafiltration profile during peritoneal dialysis. We did not find any correlations between diffusive mass transport coefficients for small solutes and fluid transport parameters such as osmotic conductance or fluid and volume marker absorption. We may thus conclude that the pathway(s) for fluid transport appears to be partly independent from the pathway(s) for small solute transport, which supports the hypothesis of different pore types for fluid and solute transport.

Controlling Fluid Flow in the Subsurface through Ureolysis-Controlled Mineral Precipitation

NASA Astrophysics Data System (ADS)

Gerlach, R.; Phillips, A. J.; Cunningham, A. B.; Spangler, L.

2016-12-01

In situ urea hydrolysis has been used by us successfully to manipulate the carbonate alkalinity and control the precipitation of carbonate minerals. Urea hydrolysis can be promoted using microbial cells, enzymes or thermal energy. This technology can be used to mitigate leakage pathways, seal fractures or control fluid transport in the subsurface in hydrocarbon production, enhanced geothermal energy storage, carbon sequestration, nuclear waste disposal, etc. We have completed two field demonstrations of the urea hydrolysis-controlled in situ mineral precipitation technology. The first demonstration showed fracture sealing was possible in a sandstone formation approx. 1120' below ground surface (bgs) and that the fracture had increased resistance to re-fracturing after mineralization treatment. The second field demonstration was performed in a well with an identified channel in the cement near the wellbore at approx. 1020' bgs. The in situ mineralization treatment resulted in reduced pressure decay during shut in periods and reduced injectivity. In addition, a noticeable difference was observed in the solids percentage in the ultrasonic imaging logs before and after biomineralization treatment. The presentation will summarize and put into context the field and our recent laboratory research focusing on permeability manipulation using the in situ ureolysis-driven mineralization technology under ambient and subsurface pressure conditions. We have demonstrated permeability reductions of 3-6 orders of magnitude in 100 µm to 4mm gaps between shale, sandstone and cement/steel interfaces.

A Case for Thinking Without Consciousness.

PubMed

Dijksterhuis, Ap; Strick, Madelijn

2016-01-01

People can engage in prolonged thought processes, such as when they are facing an important decision or when they are working on a scientific discovery. Such thought processes can take months or even years. We argue that while people engage in such thinking, they make progress not only when they consciously think but also sometimes when they are consciously thinking about something else-that is, while they think unconsciously. We review the literature on unconscious thought (UT) processes and conclude that there is indeed quite some evidence for UT. Conceptualized as a form of unconscious goal pursuit, UT is likely to be especially fruitful for thought processes that are complex, important, or interesting to the thinker. In addition, we discuss other characteristics of the UT process. We end with proposing Type 3 processes, in addition to Type 1 and Type 2 (or Systems 1 and 2) processes, to accommodate prolonged thought processes in models on thought. © The Author(s) 2015.

A university system's approach to enhancing the educational mission of health science schools and institutions: the University of Texas Academy of Health Science Education

PubMed Central

Buja, L. Maximilian; Cox, Susan M.; Lieberman, Steven A.; MacClements, Jonathan; Williams, Janet F.; Esterl, Robert M.; Shine, Kenneth I.

2013-01-01

Background The academy movement developed in the United States as an important approach to enhance the educational mission and facilitate the recognition and work of educators at medical schools and health science institutions. Objectives Academies initially formed at individual medical schools. Educators and leaders in The University of Texas System (the UT System, UTS) recognized the academy movement as a means both to address special challenges and pursue opportunities for advancing the educational mission of academic health sciences institutions. Methods The UTS academy process was started by the appointment of a Chancellor's Health Fellow for Education in 2004. Subsequently, the University of Texas Academy of Health Science Education (UTAHSE) was formed by bringing together esteemed faculty educators from the six UTS health science institutions. Results Currently, the UTAHSE has 132 voting members who were selected through a rigorous, system-wide peer review and who represent multiple professional backgrounds and all six campuses. With support from the UTS, the UTAHSE has developed and sustained an annual Innovations in Health Science Education conference, a small grants program and an Innovations in Health Science Education Award, among other UTS health science educational activities. The UTAHSE represents one university system's innovative approach to enhancing its educational mission through multi- and interdisciplinary as well as inter-institutional collaboration. Conclusions The UTAHSE is presented as a model for the development of other consortia-type academies that could involve several components of a university system or coalitions of several institutions. PMID:23490406

PREFACE: 19th International Conference on the Application of High Magnetic Fields in Semiconductor Physics and Nanotechnology (HMF-19)

NASA Astrophysics Data System (ADS)

Muraki, Koji; Takeyama, Shojiro

2011-12-01

This volume contains invited and contributed papers from the 19th International Conference on the Application of High Magnetic Fields in Semiconductor Physics and Nanotechnology (HMF-19) held in Fukuoka, Japan, from 1-6 August 2010. This conference was mainly sponsored by the Tokyo University-'Horiba International fund', which was donated by Dr Masao Horiba, the founder of Horiba Ltd. The scientific program of HMF-19 consisted of 37 invited talks, 24 contributed talks, and 83 posters, which is available from the conference homepage http://www.hmf19.iis.u-tokyo.ac.jp/index.html. Each manuscript submitted for publication in this volume has been independently reviewed. The Editor is very grateful to all the reviewers for their quick responses and helpful reports and to all the authors for their submissions and patience for the delay in the editorial process. Finally, the Editor would like to express his sincere gratitude to all the individuals involved in the conference organization and all the attendees, who made this conference so successful. Koji Muraki Conference photograph Committees Chair Conference chairS Takeyama(ISSP-UT) Conference secretary T Machida (IIS-UT) Program chair K Muraki (NTT) Local organizing chair K Oto (Chiba Univ.) Advisory Committee International Domestic L Brey (ES) T Ando (TIT) Z H Chen (CN) Y Hirayama (Tohoku Univ.) S Das Sarma (US) G Kido (NIMS) L Eaves (GB) N Miura (JP) J P Eisenstein (US) J Nitta (Tohoku Univ.) K Ensslin (CH) T Takamasu (NIMS) J Furdyna (US) G M Gusev (BR) I Kukushkin (RU) Z D Kvon (RU) G Landwehr (DE) J C Maan (NL) A H MacDonald (US) N F Oliveira Jr (BR) A Pinczuk (US) J C Portal (FR) A Sachrajda (CA) M K Sanyal(IN) R Stepniewski(PL) Program Committee Chair: K Muraki(NTT) International Domestic G Bauer (AU) H Ajiki (Osaka Univ.) G Boebinger (US) H Aoki (Hongo, UT) S Ivanov (RU) K Nomura (RIKEN) K von Klitzing (DE) T Okamoto (Hongo, UT) R Nicholas (GB) T Osada (ISSP-UT ) M Potemski (FR) N Studart (BR) U Zeitler (NL) Local Organizing Committee Chair: K Oto(Chiba Univ.) Y H Matsuda (ISSP-UT) H Yokoi (Kumamoto Univ.) M Itoh (IIS-UT) M Noda (ISSP-UT) H Sawabe (ISSP-UT) Sponsors Horiba International Conference (Dr Masao Horiba's Donation) The University of Tokyo Fukuoka City The Institute for Solid State Physics, The University of Tokyo The Global Center of Excellence for Physical Sciences Frontier, The University of Tokyo

Mechanistic insights into osmolyte action in protein stabilization under harsh conditions: N-methylacetamide in glycine betaine-urea mixture

NASA Astrophysics Data System (ADS)

Kumar, Narendra; Kishore, Nand

2014-10-01

Glycine betaine (GB), a small naturally occurring osmolyte, stabilizes proteins and counteracts harsh denaturing conditions such as extremes of temperature, cellular dehydration, and presence of high concentration of urea. In spite of several studies on understanding mechanism of protein stabilization and counteraction of these harsh conditions by osmolytes, studies centred on GB, one of the most important osmolyte, are scarce, hence, there is need for more investigations. To explore mechanism of protein stabilization and counteraction of denaturing property of urea by GB, molecular dynamics studies of N-methylacetamide (NMA), a model peptide representing denatured state of a protein, in the presence of GB, urea, and GB-urea mixture were carried out. The results show that GB and urea work such that the strength of GB as a protecting osmolyte is increased and the denaturing ability of urea is decreased in the GB-urea mixture. It can be inferred that GB counteracts urea by decreasing its hydrophobic interactions with proteins. The mutual interactions between GB and urea also play an important role in protein stabilization. This study provides insights on osmolyte induced counteraction of denaturing property of urea.

Local over-expression of VEGF-DΔNΔC in the uterine arteries of pregnant sheep results in long-term changes in uterine artery contractility and angiogenesis.

PubMed

Mehta, Vedanta; Abi-Nader, Khalil N; Shangaris, Panicos; Shaw, S W Steven; Filippi, Elisa; Benjamin, Elizabeth; Boyd, Michael; Peebles, Donald M; Martin, John; Zachary, Ian; David, Anna L

2014-01-01

The normal development of the uteroplacental circulation in pregnancy depends on angiogenic and vasodilatory factors such as vascular endothelial growth factor (VEGF). Reduced uterine artery blood flow (UABF) is a common cause of fetal growth restriction; abnormalities in angiogenic factors are implicated. Previously we showed that adenovirus (Ad)-mediated VEGF-A165 expression in the pregnant sheep uterine artery (UtA) increased nitric oxide synthase (NOS) expression, altered vascular reactivity and increased UABF. VEGF-D is a VEGF family member that promotes angiogenesis and vasodilatation but, in contrast to VEGF-A, does not increase vascular permeability. Here we examined the effect of Ad.VEGF-DΔNΔC vector encoding a fully processed form of VEGF-D, on the uteroplacental circulation. UtA transit-time flow probes and carotid artery catheters were implanted in mid-gestation pregnant sheep (n = 5) to measure baseline UABF and maternal haemodynamics respectively. 7-14 days later, after injection of Ad.VEGF-DΔNΔC vector (5×10(11) particles) into one UtA and an Ad vector encoding β-galactosidase (Ad.LacZ) contralaterally, UABF was measured daily until scheduled post-mortem examination at term. UtAs were assessed for vascular reactivity, NOS expression and endothelial cell proliferation; NOS expression was studied in ex vivo transduced UtA endothelial cells (UAECs). At 4 weeks post-injection, Ad.VEGF-DΔNΔC treated UtAs showed significantly lesser vasoconstriction (Emax144.0 v/s 184.2, p = 0.002). There was a tendency to higher UABF in Ad.VEGF-DΔNΔC compared to Ad.LacZ transduced UtAs (50.58% v/s 26.94%, p = 0.152). There was no significant effect on maternal haemodynamics. An increased number of proliferating endothelial cells and adventitial blood vessels were observed in immunohistochemistry. Ad.VEGF-DΔNΔC expression in cultured UAECs upregulated eNOS and iNOS expression. Local over-expression of VEGF-DΔNΔC in the UtAs of pregnant mid-gestation sheep reduced vasoconstriction, promoted endothelial cell proliferation and showed a trend towards increased UABF. Studies in cultured UAECs indicate that VEGF-DΔNΔC may act in part through upregulation of eNOS and iNOS.

21 CFR 862.1770 - Urea nitrogen test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

21 CFR 862.1770 - Urea nitrogen test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

21 CFR 862.1770 - Urea nitrogen test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

21 CFR 862.1770 - Urea nitrogen test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

21 CFR 862.1770 - Urea nitrogen test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

Role of urea in the postprandial urine concentration cycle of the insectivorous bat Antrozous pallidus.

PubMed

Bassett, John E

2004-02-01

Insectivorous bats, which feed once daily, produce maximally concentrated urine only after feeding. The role of urea as an osmolyte in this process was investigated in pallid bats (Antrozous pallidus) in the laboratory. Following a 24-h fast, plasma and urine were sampled before and 2 h after feeding in postprandial (PP) animals and before and 2 h after similar treatment without feeding in nonfed (NF) animals. Food consumption by PP animals and handling of NF animals had no effect on blood water content as measured by hematocrit and plasma oncotic pressure. Food consumption increased both plasma osmolality (P(osm)) and plasma urea (P(urea)) by as much as 15%. Food consumption also increased urine osmolality (U(osm)) and urine urea (U(urea)) by 50-100%. Feeding increased U(osm) regardless of changes in P(osm), and elevation of U(osm) resulted primarily from increased U(urea). In NF bats, P(osm) and P(urea) were unchanged, while U(osm) and U(urea) increased by as much as 25%. Again, increased U(osm) resulted primarily from increased U(urea). The PP urine concentration cycle of pallid bats resulted from increased urea excretion in response to apparent rapid urea synthesis. Bats rapidly metabolized protein and excreted urea following feeding when body water was most plentiful.

Reverse osmosis filtration for space mission wastewater: membrane properties and operating conditions

NASA Technical Reports Server (NTRS)

Lee, S.; Lueptow, R. M.

2001-01-01

Reverse osmosis (RO) is a compact process that has potential for the removal of ionic and organic pollutants for recycling space mission wastewater. Seven candidate RO membranes were compared using a batch stirred cell to determine the membrane flux and the solute rejection for synthetic space mission wastewaters. Even though the urea molecule is larger than ions such as Na+, Cl-, and NH4+, the rejection of urea is lower. This indicates that the chemical interaction between solutes and the membrane is more important than the size exclusion effect. Low pressure reverse osmosis (LPRO) membranes appear to be most desirable because of their high permeate flux and rejection. Solute rejection is dependent on the shear rate, indicating the importance of concentration polarization. A simple transport model based on the solution-diffusion model incorporating concentration polarization is used to interpret the experimental results and predict rejection over a range of operating conditions. Grant numbers: NAG 9-1053.

Supply-limited horizontal sand drift at an ephemerally crusted, unvegetated saline playa

USGS Publications Warehouse

Gillette, Dale A.; Niemeyer, T.C.; Helm, P.J.

2001-01-01

A site at Owens Dry Lake was observed for more than 4 years. The site was a vegetation-free saline playa where the surface formed "ephemeral crusts," crusts that form after rainfall. Sometimes these crusts were destroyed and often a layer of particles on the crust would engage in vigorous aeolian activity. Three "phases" of active sand drifting are defined as almost no movement (extreme supply limitation), loose particles on crust with some degree of sand drift (moderate supply limitation), and unlimited source movement corresponding to a destroyed surface crust (unlimited supply). These "phases" occurred 45, 49, and 6% of the time, respectively. The accumulation of loose particles on the crust was mostly the result of in situ formation. Crusted sediments with loose particles on top can exhibit mass flux rates about the same as for noncrusted sediments. Crusted sediments limit or eliminate sand drift in two conditions: for rough crusts that effect a sufficiently high threshold friction velocity (above the wind friction velocity) and for limited amounts of loose particles on the crust where particle supply is less than would be transported in normal saltation for a thick sandy surface. These "supply-limited" cases are similar to wind erosion of limited spilled material on a hard concrete surface. We quantified "supply limitation" by defining a "potential" or "supply unlimited" sand drift function Q = AG where A represents supply limitation that decreases as the particle source is depleted. Here Q is the mass of sand transported through a surface perpendicular to the ground and to the wind and having unit width during time period t, and G = ??? u*(u*2 - u*t2) dt for u* > u*t. G is integrated for the same time period t as for Q, u* is the friction velocity of the wind, and u*t is the threshold friction velocity of the wind. Hard crusts (usually formed in the summer) tended to show almost no change of threshold friction velocity with time and often gave total protection from wind erosion. Rough crusts provided sufficient protection expressed as high threshold friction velocities. For these high threshold friction velocities, aeolian activity was greatly reduced or practically prevented. The softest crusts, usually formed in the winter, provided much less protection and sometimes were destroyed by the wind. Following this destruction the "potential" or "supply unlimited" sand drift would be observed. Copyright 2000 by the American Geophysical Union.

Synergistic behavior of glycine betaine-urea mixture: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Kumar, Narendra; Kishore, Nand

2013-09-01

Glycine betaine (GB) is one of the most important osmolyte which is known to stabilize proteins as well as counteract the denaturing effect of urea. There have been many studies indicating protein stabilization and counteraction of the effect of urea by GB. However, the exact mechanism of counteraction is still debated and is of important research interest. In this study, distribution functions, hydrogen bonds, and energetics were analysed to understand different interactions between GB and urea, and their solvation properties in presence of each other. The results show that in the GB-urea mixture, GB acted as a stronger osmolyte and urea became a weaker denaturing agent than its individual counterparts. The increase in the solvation of urea and GB in GB-urea mixture and their mutual interactions through hydrogen bonding and coulombic energy resulted in more involvement of GB and urea with solvent as well as with themselves. This might result in the increase of the exclusion of GB from protein surface and decrease in the protein-urea interactions in the mixture. This synergistic behavior might be the prime reason for the counteraction of denaturing effect of urea by GB.

Mare and foal survival and subsequent fertility of mares treated for uterine torsion.

PubMed

Spoormakers, T J P; Graat, E A M; ter Braake, F; Stout, T A E; Bergman, H J

2016-03-01

Previous surveys have reported that mare and foal survival after correction of uterine torsion (UT) varies from 60 to 84% and from 30 to 54%, respectively. Furthermore, resolution via a standing flank laparotomy (SFL) has been associated with better foal, but not mare, survival. To compare the success of SFL with other correction methods (e.g. midline or flank laparotomy under general anaesthesia; correction per vaginam). Retrospective analysis of clinical records. Data on correction technique, stage of gestation, degree of rotation, survival and subsequent fertility for 189 mares treated for UT at 3 equine referral hospitals in The Netherlands during 1987-2007 were analysed. Mean stage of gestation at diagnosis was 283 days (range 153-369 days), with the majority of UTs (77.5%) occurring before Day 320 of gestation. After correction of UT, 90.5% of mares and 82.3% of foals survived to hospital discharge, between 3 and 39 days later, and to foaling. Multivariable logistic regression indicated that correction method and stage of gestation at UT affected survival of foals and mares. For foals, survival was 88.7% after SFL compared with 35.0% after other methods (P = 0.001). When UT occurred at <320 days, 90.6% of foals survived, compared with 56.1% at ≥320 days (P = 0.007). For mare survival, an interaction between stage of gestation and correction method was detected (P = 0.02), with higher survival after SFL (97.1%) than other methods (50.0%) at <320 days of gestation (P<0.01). When UT occurred at ≥320 days, mare survival did not differ between techniques (76.0 vs. 68.8%; P = 0.6). Of 123 mares that were bred again, 93.5% became pregnant; fertility did not differ between mares treated by SFL (93.9%) and other techniques (87.5%; P = 0.9). Standing flank laparotomy is the surgical technique of choice for resolving uncomplicated equine UT (i.e. with no coexisting gastrointestinal lesions) except when the stage of gestation exceeds 320 days. © 2015 EVJ Ltd.

Urea, a true uremic toxin: the empire strikes back.

PubMed

Lau, Wei Ling; Vaziri, Nosratola D

2017-01-01

Blood levels of urea rise with progressive decline in kidney function. Older studies examining acute urea infusion suggested that urea was well-tolerated at levels 8-10× above normal values. More recent in vitro and in vivo work argue the opposite and demonstrate both direct and indirect toxicities of urea, which probably promote the premature aging phenotype that is pervasive in chronic kidney disease (CKD). Elevated urea at concentrations typically encountered in uremic patients induces disintegration of the gut epithelial barrier, leading to translocation of bacterial toxins into the bloodstream and systemic inflammation. Urea induces apoptosis of vascular smooth muscle cells as well as endothelial dysfunction, thus directly promoting cardiovascular disease. Further, urea stimulates oxidative stress and dysfunction in adipocytes, leading to insulin resistance. Finally, there are widespread indirect effects of elevated urea as a result of the carbamylation reaction, where isocyanic acid (a product of urea catabolism) alters the structure and function of proteins in the body. Carbamylation has been linked with renal fibrosis, atherosclerosis and anaemia. In summary, urea is a re-emerging Dark Force in CKD pathophysiology. Trials examining low protein diet to minimize accumulation of urea and other toxins suggest a clinical benefit in terms of slowing progression of CKD. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Prediction of UT1-UTC, LOD and AAM χ3 by combination of least-squares and multivariate stochastic methods

NASA Astrophysics Data System (ADS)

Niedzielski, Tomasz; Kosek, Wiesław

2008-02-01

This article presents the application of a multivariate prediction technique for predicting universal time (UT1-UTC), length of day (LOD) and the axial component of atmospheric angular momentum (AAM χ 3). The multivariate predictions of LOD and UT1-UTC are generated by means of the combination of (1) least-squares (LS) extrapolation of models for annual, semiannual, 18.6-year, 9.3-year oscillations and for the linear trend, and (2) multivariate autoregressive (MAR) stochastic prediction of LS residuals (LS + MAR). The MAR technique enables the use of the AAM χ 3 time-series as the explanatory variable for the computation of LOD or UT1-UTC predictions. In order to evaluate the performance of this approach, two other prediction schemes are also applied: (1) LS extrapolation, (2) combination of LS extrapolation and univariate autoregressive (AR) prediction of LS residuals (LS + AR). The multivariate predictions of AAM χ 3 data, however, are computed as a combination of the extrapolation of the LS model for annual and semiannual oscillations and the LS + MAR. The AAM χ 3 predictions are also compared with LS extrapolation and LS + AR prediction. It is shown that the predictions of LOD and UT1-UTC based on LS + MAR taking into account the axial component of AAM are more accurate than the predictions of LOD and UT1-UTC based on LS extrapolation or on LS + AR. In particular, the UT1-UTC predictions based on LS + MAR during El Niño/La Niña events exhibit considerably smaller prediction errors than those calculated by means of LS or LS + AR. The AAM χ 3 time-series is predicted using LS + MAR with higher accuracy than applying LS extrapolation itself in the case of medium-term predictions (up to 100 days in the future). However, the predictions of AAM χ 3 reveal the best accuracy for LS + AR.

Direct Measurements of the Convective Recycling of the Upper Troposphere

NASA Technical Reports Server (NTRS)

Bertram, Timothy H.; Perring, Anne E.; Wooldridge, Paul J.; Crounse, John D.; Kwan, Alan J.; Wennberg, Paul O.; Scheuer, Eric; Dibb, Jack; Avery, Melody; Sachse, Glen;

Assessment of Health Effects of Exogenous Urea: Summary and Key Findings.

PubMed

Dickerson, Aisha S; Lee, Janice S; Keshava, Channa; Hotchkiss, Andrew; Persad, Amanda S

2018-05-01

Urea has been utilized as a reductant in diesel fuels to lower emission of nitrogen oxides, igniting interest in probable human health hazards associated with exposure to exogenous urea. Here, we summarize and update key findings on potential health effects of exogenous urea, including carcinogenicity. No definitive target organs for oral exposure were identified; however, results in animal studies suggest that the liver and kidney could be potential target organs of urea toxicity. The available human-subject literature suggests that the impact on lung function is minimal. Based on the literature on exogenous urea, we concluded that there was inadequate information to assess the carcinogenic potential of urea, or perform a quantitative assessment to derive reference values. Given the limited information on exogenous urea, additional research to address gaps for exogenous urea should include long-term cancer bioassays, two-generation reproductive toxicity studies, and mode-of-action investigations.

Evaluation of the Determination of Free Urea in Water-Soluble Liquid Fertilizers Containing Urea and Ureaforms by Urease and HPLC Methods.

PubMed

Hojjatie, Michael M; Abrams, Dean

2015-01-01

Currently there are three AOAC Official Methods for the determination of urea in fertilizers. AOAC Official Method 959.03, Urea in Fertilizers, Urease Method, First Action 1959, Final Action 1960, is based on the use of fresh commercial 1% urease solution, or preparation of such solution from urease powder in water, or from jack bean meal in water. AOAC Official Method 983.01, Urea and Methyleneureas (Water-Soluble) in Fertilizers, First Action 1983, Final Action 1984, is based on LC with a refractive index detector using water as the mobile phase and a C18 column. AOAC Official Method 2003.14, Determination of Urea in Water- Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions, First Action 2003, Final Action 2008, is based on LC with a UV detector using acetonitrile-water (85+15, v/v) mobile phase and a propylamine column. The urea method, AOAC Official Method 959.03, is very much dependent on the nature of the urease enzyme. The method was developed in 1960 and used for simple urea fertilizer solutions. With the advent of complex fertilizer compositions, especially with the class of liquid triazone fertilizers and water-soluble urea forms, the analyses of free urea in these fertilizers by the urease method is often inaccurate and inconsistent. AOAC Official Method 983.01 is not always reliable due to the interference of some of the components of these fertilizers, and due to the fact that the use of water as the mobile phase does not always separate the free urea from other components. AOAC Official Method 2003.14 was subjected to ring test studies that showed it could be used for the determination of "free urea" in these classes of fertilizers with good accuracy and precision.

Combining Urease and Nitrification Inhibitors with Incorporation Reduces Ammonia and Nitrous Oxide Emissions and Increases Corn Yields.

PubMed

Drury, Craig F; Yang, Xueming; Reynolds, W Dan; Calder, Wayne; Oloya, Tom O; Woodley, Alex L

2017-09-01

Less than 50% of applied nitrogen (N) fertilizer is typically recovered by corn ( L.) due to climatic constraints, soil degradation, overapplication, and losses to air and water. Two application methods, two N sources, and two inhibitors were evaluated to reduce N losses and enhance crop uptake. The treatments included broadcast urea (BrUrea), BrUrea with a urease inhibitor (BrUrea+UI), BrUrea with a urease and a nitrification inhibitor (BrUrea+UI+NI), injection of urea ammonium nitrate (InjUAN), and injected with one or both inhibitors (InjUAN+UI, InjUAN+UI+NI), and a control. The BrUrea treatment lost 50% (64.4 kg N ha) of the applied N due to ammonia volatilization, but losses were reduced by 64% with BrUrea+UI+NI (23.0 kg N ha) and by 60% with InjUAN (26.1 kg N ha). Ammonia losses were lower and crop yields were greater in 2014 than 2013 as a result of the more favorable weather when N was applied in 2014. When ammonia volatilization was reduced by adding a urease inhibitor, NO emissions were increased by 30 to 31% with BrUrea+UI and InjUAN+UI compared with BrUrea and InjUAN, respectively. Pollution swapping was avoided when both inhibitors were used (BrUrea+UI+NI, InjUAN+UI+NI) as both ammonia volatilization and NO emissions were reduced, and corn grain yields increased by 5% with BrUrea+UI+NI and by 7% with InjUAN+UI+NI compared with BrUrea and InjUAN, respectively. The combination of two N management strategies (InjUAN+UI+NI) increased yields by 19% (12.9 t ha) compared with BrUrea (10.8 t ha). Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Can flavonoid-rich chocolate modulate arterial elasticity and pathological uterine artery Doppler blood flow in pregnant women? A pilot study.

PubMed

von Wowern, Emma; Olofsson, Per

2018-09-01

Dark chocolate has shown beneficial effects on cardiovascular health and might also modulate hypertensive complications in pregnancy and uteroplacental blood flow. Increased uteroplacental resistance is associated with systemic arterial stiffness. We aimed to investigate the short-term effect of flavonoid-rich chocolate on arterial stiffness and Doppler blood flow velocimetry indexes in pregnant women with compromised uteroplacental blood flow. Doppler blood flow velocimetry and digital pulse wave analysis (DPA) were performed in 25 women pregnant in the second and third trimesters with uterine artery (UtA) score (UAS) 3-4, before and after 3 days of ingestion of chocolate with high flavonoid and antioxidant contents. UtA pulsatility index (PI), UtA diastolic notching, UAS (semiquantitative measure of PI and notching combined), and umbilical artery PI were calculated, and DPA variables representing central and peripheral maternal arteries were recorded. Mean UtA PI (p = .049) and UAS (p = .025) significantly decreased after chocolate consumption. There were no significant changes in UtA diastolic notching or any DPA indexes of arterial stiffness/vascular tone. Chocolate may have beneficial effects on the uteroplacental circulation, but in this pilot study, we could not demonstrate effects on arterial vascular tone as assessed by DPA.

Breakout Reconnection Observed by the TESIS EUV Telescope

NASA Astrophysics Data System (ADS)

Reva, A. A.; Ulyanov, A. S.; Shestov, S. V.; Kuzin, S. V.

2016-01-01

We present experimental evidence of the coronal mass ejection (CME) breakout reconnection, observed by the TESIS EUV telescope. The telescope could observe solar corona up to 2 R⊙ from the Sun center in the Fe 171 Å line. Starting from 2009 April 8, TESIS observed an active region (AR) that had a quadrupolar structure with an X-point 0.5 R⊙ above photosphere. A magnetic field reconstructed from the Michelson Doppler Imager data also has a multipolar structure with an X-point above the AR. At 21:45 UT on April 9, the loops near the X-point started to move away from each other with a velocity of ≈7 km s-1. At 01:15 UT on April 10, a bright stripe appeared between the loops, and the flux in the GOES 0.5-4 Å channel increased. We interpret the loops’ sideways motion and the bright stripe as evidence of the breakout reconnection. At 01:45 UT, the loops below the X-point started to slowly move up. At 15:10 UT, the CME started to accelerate impulsively, while at the same time a flare arcade formed below the CME. After 15:50 UT, the CME moved with constant velocity. The CME evolution precisely followed the breakout model scenario.

Influence of fatigue and velocity on the latency and recruitment order of scapular muscles.

PubMed

Mendez-Rebolledo, Guillermo; Gatica-Rojas, Valeska; Guzman-Muñoz, Eduardo; Martinez-Valdes, Eduardo; Guzman-Venegas, Rodrigo; Berral de la Rosa, Francisco Jose

2018-07-01

To determine the influence of velocity and fatigue on scapular muscle activation latency and recruitment order during a voluntary arm raise task, in healthy individuals. Cross-sectional study. University laboratory. Twenty three male adults per group (high-velocity and low-velocity). Onset latency of scapular muscles [Anterior deltoid (AD), lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), and serratus anterior (SA)] was assessed by surface electromyography. The participants were assigned to one of two groups: low-velocity or high-velocity. Both groups performed a voluntary arm raise task in the scapular plane under two conditions: no-fatigue and fatigue. The UT showed early activation (p < 0.01) in the fatigue condition when performing the arm raise task at a high velocity. At a low velocity and with no muscular fatigue, the recruitment order was MT, LT, SA, AD, and UT. However, the recruitment order changed in the high-velocity with muscular fatigue condition, since the recruitment order was UT, AD, SA, LT, and MT. The simultaneous presence of fatigue and high-velocity in an arm raise task is associated with a decrease in the UT activation latency and a modification of the recruitment order of scapular muscles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Five-Year (2004-2009)Observations of Upper Tropospheric Water Vapor and Cloud Ice from MLS and Comparisons with GEOS-5 Analyses

NASA Technical Reports Server (NTRS)

Jiang, Jonathan H.; Su, Hui; Pawson, Steven; Liu, Hui-Chun; Read, William; Waters, Joe W.; Santee, Michelle; Wu, Dong L.; Schwartz, Michael; Lambert, Alyn;

Dispersion Interactions between Urea and Nucleobases Contribute to the Destabilization of RNA by Urea in Aqueous Solution

PubMed Central

Kasavajhala, Koushik; Bikkina, Swetha; Patil, Indrajit; MacKerell, Alexander D.; Priyakumar, U. Deva

2015-01-01

Urea has long been used to investigate protein folding and, more recently, RNA folding. Studies have proposed that urea denatures RNA by participating in stacking interactions and hydrogen bonds with nucleic acid bases. In this study, the ability of urea to form unconventional stacking interactions with RNA bases is investigated using ab initio calculations (RI-MP2 and CCSD(T) methods with the aug-cc-pVDZ basis set). A total of 29 stable nucleobase-urea stacked complexes are identified in which the intermolecular interaction energies (up to −14 kcal/mol) are dominated by dispersion effects. Natural bond orbital (NBO) and atoms in molecules (AIM) calculations further confirm strong interactions between urea and nucleobases. Calculations on model systems with multiple urea and water molecules interacting with a guanine base lead to a hypothesis that urea molecules along with water are able to form cage-like structures capable of trapping nucleic acid bases in extrahelical states by forming both hydrogen bonded and dispersion interactions, thereby contributing to the unfolding of RNA in the presence of urea in aqueous solution. PMID:25668757

Urea nitrate, an exceptionally easy-to-make improvised explosive: studies towards trace characterization.

PubMed

Tamiri, Tsippy; Rozin, Rinat; Lemberger, Nitay; Almog, Joseph

2009-09-01

Urea nitrate is a powerful improvised explosive, frequently used by terrorists in the Israeli arena. It was also used in the first World Trade Center bombing in New York in February 1993. It is difficult to identify urea nitrate in post-explosion debris, since only a very small fraction survives the blast. Also, in the presence of water, it readily decomposes to its original components, urea and nitric acid. It is suspected that post-blast debris of urea nitrate can be confused with ammonium nitrate, the main solid product of urea nitrate thermal decomposition. In a comprehensive study towards identification of urea nitrate in post-blast traces, a spectrophotometric technique for quantitative determination of urea nitrate was developed, and conditions were found for extraction and separation of un-exploded traces of urea nitrate with minimal decomposition. Nevertheless, out of 28 samples collected from a series of three controlled firings of urea nitrate charges, only one gave the typical adduct ion by liquid chromatography/mass spectrometry analysis. We found that urea nitrate can be extracted from solid mixtures to organic solvents by using Crown ethers as "host compounds." The adducts thus formed are solid, crystalline compounds that can be characterized by microanalysis and spectroscopic techniques.

Revisiting the IAGOS-CARIBIC CO and O3 observations and their correlation in the UT/LS

NASA Astrophysics Data System (ADS)

Boenisch, Harald; Zahn, Andreas; Brenninkmeijer, Carl; Williams, Jonathan; Rauthe-Schöch, Armin; Scharffe, Dieter; van Velthoven, Peter

2017-04-01

The CARIBIC research project, the predecessor of the actual IAGOS-CARIBIC project, is divided into two distinct phases: 1997-2002 and 2005-2016. Here, we will present a reassessment of CO and O3 observed during IAGOS-CARIBIC. The distribution and particularly the tracer-tracer correlation of both species has been widely used as a diagnostic tool for UT/LS transport processes (e.g. Hoor et al., 2002 and 2004; Pan et al., 2004). Up to now, only the early phase of CARIBIC observations of CO and O3 has been applied for transport studies in the tropopause region (Zahn et al., 2000 and 2002). The focus of this work here will be on the variability of the CO-O3 distribution and correlation on seasonal and interannual timescales in the extratropics using the IAGOS-CARIBIC in-situ measurements of CO and O3 spanning a time period from 1997 to 2016 with more than 400 flights. For a more detailed analysis and understanding of the underlying transport processes, the observations will be interpreted in combination with meteorological reanalysis data sets. The distribution of CO and O3 will be analysed relative to different tropopause definitions (chemical, dynamical, thermal) and in different coordinate systems (e.g. equivalent latitude, potential temperature, potential vorticity and distance to the tropopause). Also, the role of static stability and the tropopause inversion layer (TIL) on the tracer distribution will be investigated. Hoor, P., H. Fischer, L. Lange, J. Lelieveld, and D. Brunner (2002), Seasonal variations of a mixing layer in the lowermost stratosphere as identified by the CO-O3 correlation from in situ measurements, J. Geophys. Res., 107(D5), 4044, doi:10.1029/2000JD000289. Hoor, P., C. Gurk, D. Brunner, M. I. Hegglin, H. Wernli, and H. Fischer (2004), Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT, Atmos. Chem. Phys., 4, 1427-1442. Pan, L. L., W. J. Randel, B. L. Gary, M. J. Mahoney, and E. J. Hintsa (2004), Definitions and sharpness of the extratropical tropopause: A trace gas perspective, J. Geophys. Res., 109, D23103, doi:10.1029/ 2004JD004982.

Does low dose (13)C-urea breath test maintain a satisfactory accuracy in diagnosing Helicobacter pylori infection?

PubMed

Coelho, Luiz Gonzaga Vaz; Silva, Arilto Eleutério da; Coelho, Maria Clara de Freitas; Penna, Francisco Guilherme Cancela e; Ferreira, Rafael Otto Antunes; Santa-Cecilia, Elisa Viana

2011-01-01

The standard doses of (13)C-urea in (13)C-urea breath test is 75 mg. To assess the diagnostic accuracy of (13)C-urea breath test containing 25 mg of (13)C-urea comparing with the standard doses of 75 mg in the diagnosis of Helicobacter pylori infection. Two hundred seventy adult patients (96 males, 174 females, median age 41 years) performed the standard (13)C-urea breath test (75 mg (13)C-urea) and repeated the (13)C-urea breath test using only 25 mg of (13)C-urea within a 2 week interval. The test was performed using an infrared isotope analyzer. Patients were considered positive if delta over baseline was >4.0‰ at the gold standard test. One hundred sixty-one (59.6%) patients were H. pylori negative and 109 (40.4%) were positive by the gold standard test. Using receiver operating characteristic analysis we established a cut-off value of 3.4% as the best value of 25 mg (13)C-urea breath test to discriminate positive and negative patients, considering the H. pylori prevalence (95% CI: 23.9-37.3) at our setting. Therefore, we obtained to 25 mg (13)C-urea breath test a diagnostic accuracy of 92.9% (95% CI: 88.1-97.9), sensitivity 83.5% (95% CI: 75.4-89.3), specificity 99.4% (95% CI: 96.6-99.9), positive predictive value 98.3% (95% CI: 92.4-99.4), and negative predictive value 93.0% (95% CI: 88.6-96.1). Low-dose (13)C-urea breath test (25 mg (13)C-urea) does not reach accuracy sufficient to be recommended in clinical setting where a 30% prevalence of H. pylori infection is observed. Further studies should be done to determine the diagnostic accuracy of low doses of (13)C-urea in the urea breath test.

Substitution of a single amino acid residue in the aromatic/arginine selectivity filter alters the transport profiles of tonoplast aquaporin homologs.

PubMed

Azad, Abul Kalam; Yoshikawa, Naoki; Ishikawa, Takahiro; Sawa, Yoshihiro; Shibata, Hitoshi

2012-01-01

Aquaporins are integral membrane proteins that facilitate the transport of water and some small solutes across cellular membranes. X-ray crystallography of aquaporins indicates that four amino acids constitute an aromatic/arginine (ar/R) pore constriction known as the selectivity filter. On the basis of these four amino acids, tonoplast aquaporins called tonoplast intrinsic proteins (TIPs) are divided into three groups in Arabidopsis. Herein, we describe the characterization of two group I TIP1s (TgTIP1;1 and TgTIP1;2) from tulip (Tulipa gesneriana). TgTIP1;1 and TgTIP1;2 have a novel isoleucine in loop E (LE2 position) of the ar/R filter; the residue at LE2 is a valine in all group I TIPs from model plants. The homologs showed mercury-sensitive water channel activity in a fast kinetics swelling assay upon heterologous expression in Pichia pastoris. Heterologous expression of both homologs promoted the growth of P. pastoris on ammonium or urea as sole sources of nitrogen and decreased growth and survival in the presence of H(2)O(2). TgTIP1;1- and TgTIP1;2-mediated H(2)O(2) conductance was demonstrated further by a fluorescence assay. Substitutions in the ar/R selectivity filter of TgTIP1;1 showed that mutants that mimicked the ar/R constriction of group I TIPs could conduct the same substrates that were transported by wild-type TgTIP1;1. In contrast, mutants that mimicked group II TIPs showed no evidence of urea or H(2)O(2) conductance. These results suggest that the amino acid residue at LE2 position is critical for the transport selectivity of the TIP homologs and group I TIPs might have a broader spectrum of substrate selectivity than group II TIPs. Copyright © 2011 Elsevier B.V. All rights reserved.

RadNet Air Data From St. George, UT

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for St. George, UT from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Prediction of Tensile Strength of Friction Stir Weld Joints with Adaptive Neuro-Fuzzy Inference System (ANFIS) and Neural Network

NASA Technical Reports Server (NTRS)

Dewan, Mohammad W.; Huggett, Daniel J.; Liao, T. Warren; Wahab, Muhammad A.; Okeil, Ayman M.

2015-01-01

Friction-stir-welding (FSW) is a solid-state joining process where joint properties are dependent on welding process parameters. In the current study three critical process parameters including spindle speed (??), plunge force (????), and welding speed (??) are considered key factors in the determination of ultimate tensile strength (UTS) of welded aluminum alloy joints. A total of 73 weld schedules were welded and tensile properties were subsequently obtained experimentally. It is observed that all three process parameters have direct influence on UTS of the welded joints. Utilizing experimental data, an optimized adaptive neuro-fuzzy inference system (ANFIS) model has been developed to predict UTS of FSW joints. A total of 1200 models were developed by varying the number of membership functions (MFs), type of MFs, and combination of four input variables (??,??,????,??????) utilizing a MATLAB platform. Note EFI denotes an empirical force index derived from the three process parameters. For comparison, optimized artificial neural network (ANN) models were also developed to predict UTS from FSW process parameters. By comparing ANFIS and ANN predicted results, it was found that optimized ANFIS models provide better results than ANN. This newly developed best ANFIS model could be utilized for prediction of UTS of FSW joints.

Urea tolerance of myofibrillar proteins of two elasmobranchs: Squalus acanthias and Raja tengu.

PubMed

Hasnain, A; Yasui, T

1986-09-01

Some biochemical properties of actomyosin and myosin from elasmobranchs, Squalus acanthias and Raja tengu are compared with those of a freshwater (Cyprinus carpio) and a marine teleost (Seriola quinquiradiata). Whereas Ca2+-ATPase of teleost actomyosins are more stable in the absence of urea, the reverse is true for elasmobranchs up to 1.0 M urea. In contrast to that of teleosts, the Mg2+-ATPase of S. acanthias actomyosin shows an activation in the presence of urea, where as that of R. tengu persists. Below 1.0 M urea, there is low incorporation of DTNB into thiols of elasmobranch myosins, and losses in alpha-helicity are reversible up to 5.0 M urea. The results, thus, demonstrate that for a certain concentration of urea, elasmobranch myofibrillar proteins may exhibit a group specific tolerance to urea.

Comparison between transdermal nitroglycerin and sildenafil citrate in intrauterine growth restriction: effects on uterine, umbilical and fetal middle cerebral artery pulsatility indices.

PubMed

Trapani, A; Gonçalves, L F; Trapani, T F; Franco, M J; Galluzzo, R N; Pires, M M S

2016-07-01

To evaluate the effects of transdermal nitroglycerin (GTN) and sildenafil citrate on Doppler velocity waveforms of the uterine (UtA), umbilical (UA) and fetal middle cerebral (MCA) arteries in pregnancies with intrauterine growth restriction (IUGR). This was a prospective study of 35 singleton pregnancies (gestational age, 24-31 weeks) with IUGR and abnormal UtA and UA Doppler waveforms. We compared maternal arterial blood pressure and Z-scores of the pulsatility index (PI) of UtA, UA and fetal MCA before and after application of a transdermal GTN patch (average dose, 0.4 mg/h), oral sildenafil citrate (50 mg) or placebo. Statistical analysis was performed by ANOVA for paired samples. There was a significant decrease in UtA-PI after application of GTN (21.0%) and sildenafil citrate (20.4%). A significant reduction in UA-PI was also observed for both GTN (19.1%) and sildenafil citrate (18.2%). There was no difference in UtA- and UA-PI when the GTN and sildenafil groups were compared. No changes in Doppler velocimetry were observed in the placebo group and no significant change in MCA-PI was observed in any group. Maternal arterial blood pressure decreased with administration of both GTN and sildenafil citrate in those with pre-eclampsia. The use of transdermal GTN or sildenafil citrate in pregnancies with IUGR is associated with a significant reduction in both UtA and UA Doppler PI, as well as maternal arterial blood pressure. Neither drug affected the MCA-PI. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

On the Logical Development of Statistical Models.

DTIC Science & Technology

1983-12-01

David Steinberg, and Jean Wallis for their helpful cosments to a preliminary draft of this work. -21- REFERENCES [1] Anscombe, F. J. and Tukey, J. W ...effect of a known vector x of predictor variables. In this way we obtain an explicative-static or type 11 model and -3- W .- r󈧬 41 U) 3 0) H + N 1 0...dependency is: Yt M it + ut p(ut ) - U It P(ut M-t) - I - t (2.1) t W P01 + Vt-1(P11 - P0 1) where Yt can only have the values zero and one, p is its

Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer

PubMed Central

Guinn, Emily J.; Pegram, Laurel M.; Capp, Michael W.; Pollock, Michelle N.; Record, M. Thomas

2011-01-01

To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients Kp for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. Kp values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH—amide O and amide NH—amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or Kp values. PMID:21930943

Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer.

PubMed

Guinn, Emily J; Pegram, Laurel M; Capp, Michael W; Pollock, Michelle N; Record, M Thomas

2011-10-11

To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients K(p) for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. K(p) values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH--amide O and amide NH--amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or K(p) values.

Use of anaerobic hydrolysis pretreatment to enhance ultrasonic disintegration of excess sludge.

PubMed

Li, Xianjin; Zhu, Tong; Shen, Yang; Chai, Tianyu; Xie, Yuanhua; You, Meiyan; Wang, Youzhao

2016-01-01

To improve the excess sludge disintegration efficiency, reduce the sludge disintegration cost, and increase sludge biodegradability, a combined pretreatment of anaerobic hydrolysis (AH) and ultrasonic treatment (UT) was proposed for excess sludge. Results showed that AH had an advantage in dissolving flocs, modifying sludge characteristics, and reducing the difficulty of sludge disintegration, whereas UT was advantageous in damaging cell walls, releasing intracellular substances, and decomposing macromolecular material. The combined AH-UT process was an efficient method for excess sludge pretreatment. The optimized solution involved AH for 3 days, followed by UT for 10 min. After treatment, chemical oxygen demand, protein, and peptidoglycan concentrations reached 3,949.5 mg O2/L, 752.5 mg/L and 619.1 mg/L, respectively. This work has great significance for further engineering applications, namely, reducing energy consumption, increasing the sludge disintegration rate, and improving the biochemical properties of sludge.

Peripheral markers of central fatigue in trained and untrained during uncompensable heat stress.

PubMed

Wright, Heather E; Selkirk, Glen A; Rhind, Shawn G; McLellan, Tom M

2012-03-01

The development of fatigue is more pronounced in the heat than thermoneutral environments; however, it is unclear whether biomarkers of central fatigue are consistent with the higher core temperature (T (c)) tolerated by endurance trained (TR) versus untrained (UT) during exertional heat stress (EHS). The purpose of this study was to examine the indicators of central fatigue during EHS in TR versus UT. Twelve TR and 11 UT males (mean ± SE [Formula: see text] = 70 ± 2 and 50 ± 1 mL kg LBM(-1) min(-1), respectively) walked on a treadmill to exhaustion (EXH) in 40°C (dry) wearing protective clothing. Venous blood was obtained at PRE and 0.5°C T (c) increments from 38 to 40°C/EXH. Free tryptophan (f-TRP) decreased dramatically at 39.5°C for the TR. Branch chain amino acids decreased with T (c) and were greater for UT than TR at EXH. Tyrosine and phenylalanine remained unchanged. Serum S100β was undetectable (<5 pg mL(-1)). Albumin was greater for the UT from PRE to 39.0°C and at EXH. Prolactin (PRL) responded to relative thermal strain with similar EXH values despite higher T (c) tolerated for TR (39.7 ± 0.09°C) than UT (39.0 ± 0.09°C). The high EXH PRL values for both groups support its use as a biomarker of the serotonin and dopamine interplay within the brain during the development of central fatigue.

EEJ and EIA variations during modeling substorms with different onset moments

NASA Astrophysics Data System (ADS)

Klimenko, V. V.; Klimenko, M. V.

2015-11-01

This paper presents the simulations of four modeling substorms with different moment of substorm onset at 00:00 UT, 06:00 UT, 12:00 UT, and 18:00 UT for spring equinoctial conditions in solar activity minimum. Such investigation provides opportunity to examine the longitudinal dependence of ionospheric response to geomagnetic substorms. Model runs were performed using modified Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP). We analyzed GSM TIP simulated global distributions of foF2, low latitude electric field and ionospheric currents at geomagnetic equator and their disturbances at different UT moments substorms. We considered in more detail the variations in equatorial ionization anomaly, equatorial electrojet and counter equatorial electrojet during substorms. It is shown that: (1) the effects in EIA, EEJ and CEJ strongly depend on the substorm onset moment; (2) disturbances in equatorial zonal current density during substorm has significant longitudinal dependence; (3) the observed controversy on the equatorial ionospheric electric field signature of substorms can depend on the substorm onset moments, i.e., on the longitudinal variability in parameters of the thermosphere-ionosphere system.

Cluster Observations of reconnection along the dusk flank of the magnetosphere

NASA Astrophysics Data System (ADS)

Escoubet, C.-Philippe; Grison, Benjamin; Berchem, Jean; Trattner, Karlheinz; Lavraud, Benoit; Pitout, Frederic; Soucek, Jan; Richard, Robert; Laakso, Harri; Masson, Arnaud; Dunlop, Malcolm; Dandouras, Iannis; Reme, Henri; Fazakerley, Andrew; Daly, Patrick

2015-04-01

Magnetic reconnection is generally accepted to be the main process that transfers particles and energy from the solar wind to the magnetosphere. The location of the reconnection site depends on the orientation of the interplanetary magnetic field (IMF) in the solar wind: on the dayside magnetosphere for an IMF southward, on the lobes for an IMF northward and on the flanks for an IMF in the East-West direction. Since most of observations of reconnection events have sampled a limited region of space simultaneously it is still not yet know if the reconnection line is extended over large regions of the magnetosphere or if is patchy and made of many reconnection lines. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side where we observe multiple sources of reconnection/injections. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s with the density of order 5 cm-3. The four Cluster spacecraft had an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions, which leads to energy dispersions, we obtain distances of the ion sources between 14 and 20 RE from the spacecraft. The slope of the ion energy dispersions confirmed these distances. Using Tsyganenko model, we find that these sources are located on the dusk flank, past the terminator. The first injection by C3 is seen at approximately the same time as the 2nd injection on C1 but their sources at the magnetopause were separated by more than 7 RE. This would imply that two distinct sources were active at the same time on the dusk flank of the magnetosphere. In addition, a flow reversal was observed at the magnetopause on C4 which would be an indication that reconnection is also taking place near the exterior cusp quasi-simultaneously.

Midtail plasma flows and the relationship to near-Earth substorm activity: A case study

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Goodrich, C. C.; Reeves, G. D.; Belian, R. D.; Taktakishvili, A.

1994-01-01

Recent simulations of magnetotail reconnection have pointed to a link between plasma flows, dipolarization, and the substorm current wedge. In particular, Hesse and Birn (1991) have proposed that earthward jetting of plasma from the reconnection region transports flux into the near-Earth region. At the inner edge of the plasma sheet this flux piles up, producing a dipolarization of the magnetic field. The vorticity produced by the east-west deflection of the flow at the inner edge of the plasma sheet gives rise to field-aligned currents that have region 1 polarity. Thus in this scenario the earthward flow from the reconnection region produces the dipolarization ad the current wedge in a self-consistent fashion. In this study we examine observations made on April 8, 1985 by the Active Magnetospheric Particle Tracer Explorers (AMPTE)/Ion Release Module (IRM), the geosynchronous satellites 1979-053, 1983-019, and 1984-037, and Syowa station, as well as AE. This event is unique because IRM was located near the neutral sheet in the midnight sector for am extended period of time. Ground data show that there was ongoing activity in the IRM local time sector for several hours, beginning at 1800 UT and reaching a crescendo at 2300 UT. This activity was also accompanied by energetic particle variations, including injections, at geosynchronous orbit in the nighttime sector. Significantly, there were no fast flows at the neutral sheet until the great intensification of activity at 2300 UT. At that time, IRM recorded fast eartheard flow simultaneous with a dipolatization of the magetic field. We conclude that while the aforementioned scenario for the creation of the current wedge encounters serious problems explaining the earlier activity, the observations at 2300 UT are consistent with the scenario of Hesse and Birn (1191). On that basis it is argued that the physics of substorms is not exclusively rooted in the development of a global tearing mode. Processes at the inner edge of the cross-tail current that cause a disruption of the current and a consequent dipolarization and current wedge may be unrelated to the formation of a macroscale reconnection region. Thus the global evolution of a substorm is probably a complicated superposition of such processes operating on a very localized scale and a global macroscale process that allows for such things as releasing te energy stored in lobe flux and creation of plasmoids.

Insight into the effect mechanism of urea-induced protein denaturation by dielectric spectroscopy.

PubMed

Zhang, Cancan; Yang, Man; Zhao, Kongshuang

2017-12-06

Dielectric relaxation spectroscopy was applied to study how urea affects the phase transition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), which has been widely used as a protein model. It was found that there is a pronounced relaxation near 10 GHz for the ternary system of PNIPAM in urea aqueous solution. The temperature dependence of dielectric parameters indicates that urea can reduce the lower critical solution temperature (LCST) of PNIPAM, i.e., stabilize the globule state of PNIPAM and collapse the PNIPAM chains. Based on our results, the interaction mechanism of urea on the conformational transition of PNIPAM was presented: urea replaces water molecules directly bonding with PNIPAM and acts as the bridging agent for the adjacent side chains of PNIPAM. Accordingly, the mechanism with which urea denatures protein was deduced. In addition, it is worth mentioning that, from the temperature dependence of the dielectric parameters obtained in the presence of urea, an interesting phenomenon was found in which the effect of urea on PNIPAM seems to take 2 M as a unit. This result may be the reason why urea and TMAO exit marine fishes at a specific ratio of 2 : 1.

Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.

PubMed

Anderson, W Gary; Good, Jonathan P; Pillans, Richard D; Hazon, Neil; Franklin, Craig E

2005-10-01

Plasma urea levels and hepatic urea production in the euryhaline bull shark, Carcharhinus leucas, acclimated to freshwater and seawater environments were measured. It was found that plasma urea concentration increased with salinity and that this increase was, in part, the result of a significant increase in hepatic production of urea. This study provides direct evidence that hepatic production of urea plays an important role in the osmoregulatory strategy of C. leucas. (c) 2005 Wiley-Liss, Inc.

Sulfonamide antibiotic removal and nitrogen recovery from synthetic urine by the combination of rotating advanced oxidation contactor and methylene urea synthesis process.

PubMed

Fukahori, S; Fujiwara, T; Ito, R; Funamizu, N

2015-01-01

The combination of nitrogen recovery and pharmaceutical removal processes for livestock urine treatment were investigated to suppress the discharge of pollutants and recover nitrogen as resources. We combined methylene urea synthesis from urea and adsorption and photocatalytic decomposition of sulfonamide antibiotic using rotating advanced oxidation contactor (RAOC) contained for obtaining both safe fertilizer and reclaimed water. The methylene urea synthesis could recover urea in synthetic urine, however, almost all sulfonamide antibiotic was also incorporated, which is unfavorable from a safety aspect if the methylene urea is to be used as fertilizer. Conversely, RAOC could remove sulfonamide antibiotic without consuming urea. It was also confirmed that the methylene urea could be synthesized from synthetic urine treated by RAOC. Thus, we concluded that RAOC should be inserted prior to the nitrogen recovery process for effective treatment of urine and safe use of methylene urea as fertilizer.

RadNet Air Data From Salt Lake City, UT

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for Salt Lake City, UT from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle

NASA Astrophysics Data System (ADS)

Capitaine, N.; Gontier, A.-M.

1993-08-01

Present observations using modern astrometric techniques are supposed to provide the Earth orientation parameters, and therefore UT1, with an accuracy better than ±1 mas. In practice, UT1 is determined through the intermediary of Greenwich Sidereal Time (GST), using both the conventional relationship between Greenwich Mean Sidereal Time (GMST) and UTl (Aoki et al. 1982) and the so-called "equation of the equinoxes" limited to the first order terms with respect to the nutation quantities. This highly complex relation between sidereal time and UT1 is not accurate at the milliaresecond level which gives rise to spurious terms of milliaresecond amplitude in the derived UTl. A more complete relationship between GST and UT1 has been recommended by Aoki & Kinoshita (1983) and Aoki (1991) taking into account the second order terms in the difference between GST and GM ST, the largest one having an amplitude of 2.64 mas and a 18.6 yr-period. This paper explains how this complete expansion of GST implicitly uses the concept of "nonrotating origin" (NRO) as proposed by Guinot in 1979 and would, therefore, provide a more accurate value of UTl and consequently of the Earth's angular velocity. This paper shows, moreover, that such a procedure would be simplified and conceptually clarified by the explicit use of the NRO as previously proposed (Guinot 1979; Capitaine et al. 1986). The two corresponding options (implicit or explicit use of the NRO) are shown to be equivalent for defining the specific Earth's angle of rotation and then UT1. The of the use of such an accurate procedure which has been proposed in the new IERS standards (McCarthy 1992a) instead of the usual one are estimated for the practical derivation of UT1.

Testosterone prevents protein loss via the hepatic urea cycle in human.

PubMed

Lam, Teresa; Poljak, Anne; McLean, Mark; Bahl, Neha; Ho, Ken K Y; Birzniece, Vita

2017-04-01

The urea cycle is a rate-limiting step for amino acid nitrogen elimination. The rate of urea synthesis is a true indicator of whole-body protein catabolism. Testosterone reduces protein and nitrogen loss. The effect of testosterone on hepatic urea synthesis in humans has not been studied. To determine whether testosterone reduces hepatic urea production. An open-label study. Eight hypogonadal men were studied at baseline, and after two weeks of transdermal testosterone replacement (Testogel, 100 mg/day). The rate of hepatic urea synthesis was measured by the urea turnover technique using stable isotope methodology, with 15 N 2 -urea as tracer. Whole-body leucine turnover was measured, from which leucine rate of appearance (LRa), an index of protein breakdown and leucine oxidation (Lox), a measure of irreversible protein loss, were calculated. Testosterone administration significantly reduced the rate of hepatic urea production (from 544.4 ± 71.8 to 431.7 ± 68.3 µmol/min; P  < 0.01), which was paralleled by a significant reduction in serum urea concentration. Testosterone treatment significantly reduced net protein loss, as measured by percent Lox/LRa, by 19.3 ± 5.8% ( P  < 0.05). There was a positive association between Lox and hepatic urea production at baseline ( r 2  = 0.60, P  < 0.05) and after testosterone administration ( r 2  = 0.59, P  < 0.05). Testosterone replacement reduces protein loss and hepatic urea synthesis. We conclude that testosterone regulates whole-body protein metabolism by suppressing the urea cycle. © 2017 European Society of Endocrinology.

Reverse iontophoresis of urea in health and chronic kidney disease: a potential diagnostic and monitoring tool?

PubMed Central

Ebah, Leonard M; Read, Ian; Sayce, Andrew; Morgan, Jane; Chaloner, Christopher; Brenchley, Paul; Mitra, Sandip

2012-01-01

Background Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls. Methods Using a MIC 2® Iontophoresis Controller, reverse iontophoresis was applied on the forearm of five healthy subjects (controls) and 18 patients with CKD for 3–5 h. Urea extracted at the cathode was measured and compared with plasma urea. Results Reverse iontophoresis at 250 μA was entirely safe for the duration. Cathodal buffer urea linearly correlated with plasma urea after 2 h (r = 0·82, P < 0·0001), to 3·5 h current application (r = 0·89, P = 0·007). The linear equations y = 0·24x + 1 and y = 0·21x + 4·63 predicted plasma urea (y) from cathodal urea after 2 and 3 h, respectively. Cathodal urea concentration in controls was significantly lower than in patients with CKD after a minimum current application of 2 h (P < 0·0001), with the separation between the two groups becoming more apparent with longer application (P = 0·003). A cathodal urea cut-off of 30 μM gave a sensitivity of 83·3% and positive predictive value of 87% CKD. During haemodialysis, the fall in cathodal urea was able to track that of blood urea. Conclusion Reverse iontophoresis is safe, can potentially discriminate patients with CKD and healthy subjects and is able to track blood urea changes on dialysis. Further development of the technology for routine use can lead to an exciting opportunity for its use in diagnostics and monitoring. PMID:22409780

Banding of urea increased ammonia volatilization in a dry acidic soil.

PubMed

Rochette, Philippe; Macdonald, J Douglas; Angers, Denis A; Chantigny, Martin H; Gasser, Marc-Olivier; Bertrand, Normand

2009-01-01

Volatilization of ammonia following application of urea contributes to smog formation and degradation of natural ecosystems. The objective of this study was to evaluate the impact of (i) incorporation and banding of urea and (ii) surface broadcast of slow-release urea types on NH(3) volatilization in a dry acidic soil. Volatilization was measured using wind tunnels for 25 d after standard urea (140 kg N ha(-1)) was broadcast, broadcast and incorporated (0-5 cm), or incorporated in shallow bands (3-5 cm) to a conventionally tilled silty loam soil. Urea supplemented with a urease inhibitor or coated with a polymer was also broadcast at the soil surface. Little N diffused out of the polymer-coated granules and ammonia losses were low (4% of applied N). Use of a urease inhibitor also resulted in a low NH(3) loss (5% of applied N) while maintaining soil mineral N at levels similar to plots where untreated urea was broadcast. The rate of hydrolysis of urea broadcast at the soil surface was slowed by the lack of moisture and NH(3) loss (9% applied N) was the lowest of all treatments with standard urea. Incorporation of broadcast urea increased emissions (16% applied N) by increasing urea hydrolysis relative to surface application. Furthermore, incorporation in band also increased emissions (27% applied N) due to a localized increase in soil pH from 6.0 to 8.7. We conclude that incorporating urea in bands in a dry acidic soil can increase NH(3) volatilization compared to broadcast application followed by incorporation.

What Is a Urea Cycle Disorder?

MedlinePlus

... in which nitrogen, a waste product of protein metabolism, is removed from the blood and converted to a compound called urea in the blood. Normally, the urea is transferred into the urine and removed from the body. In urea cycle ...

Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays.

PubMed

Huntington, G B; Magee, K; Matthews, A; Poore, M; Burns, J

2009-04-01

Two experiments were conducted to assess effects of endophyte treatments (Exp. 1), forage species (Exp. 2), and supplementation (Exp. 2) on urea production, excretion, and recycling in beef steers. Infusion of (15,15)N-urea and enrichment of urea in urine samples were used to calculate urea-N entry and recycling to the gut. Acceptably stable enrichment of (15)N-urea in urine was obtained after 50 h of intrajugular infusion of (15,15)N-urea, indicating that valid data on urea metabolism can be obtained from steers fed forages twice daily. After adjustment by covariance for differences in N intake among treatments in Exp. 1, steers fed endophyte-infected tall fescue had less (P<0.10) urea-N entry, recycling to the gut, and return of recycled urea-N to the ornithine cycle than those fed endophyte-free or novel endophyte-infected tall fescue. However, urea-N urinary excretion or return to the gut was similar among endophyte treatments when expressed as a proportion of urea-N entry. Urea-N entry and return to the gut in Exp. 2 was similar in steers fed gamagrass or orchardgrass hay after adjustment by covariance for differences in N intake. Less (P<0.01) urinary excretion, expressed as grams per day or as a proportion of urea-N entry, with gamagrass than with orchardgrass was associated with faster in vitro NDF-N digestion with gamagrass. Supplementation of gamagrass or orchardgrass with 1.76 kg/d of readily fermentable fiber and starch decreased urea entry (P<0.06) and urinary excretion of urea (P<0.01). Interactions between hay source and supplement reflected a greater response to supplementation for steers fed orchardgrass than for those fed gamagrass. After adjustment for differences among treatments in N supply, results of both experiments support the concept of improved N use in response to increased carbohydrate fermentability in the rumen, due either to inherent differences in forage fiber or to supplementation with readily fermentable carbohydrate (starch or fiber). Closer coordination of ruminal fermentation of carbohydrate and N sources provided greater and more efficient capture of dietary N as tissue protein in forage-fed steers.

Model Dependency of TMAO's Counteracting Effect Against Action of Urea: Kast Model versus Osmotic Model of TMAO.

PubMed

Borgohain, Gargi; Paul, Sandip

2016-03-10

Classical molecular dynamics simulation of GB1 peptide (a 16-residue β-hairpin) in different osmotic environments is studied. Urea is used for denaturation of the peptide, and trimethylamine-N-oxide (TMAO) is used to offset the effect of urea. Protein-urea electrostatic interactions are found to play a major role in protein-denaturation. To emphasize on protein protecting action of TMAO against urea, two different models of TMAO are used, viz., the Kast model and the Osmotic model. We observe that the Osmotic model of TMAO gives the best protection to counteract urea's action when used in ratio 1:2 of urea:TMAO (i.e., reverse ratio). This is because the presence of TMAO makes urea-protein electrostatic interactions more unfavorable. Preferential solvation of TMAO molecules by urea (and water) molecules is also observed, which causes depletion in the number of urea molecules in the vicinity of the protein. The calculations of intraprotein hydrogen bonds between different residues of protein further reveal the breaking of backbone hydrogen bonds of residues 2 and 15 in the presence of urea, and the same is preserved in the presence of TMAO. Free energy landscapes show that the narrowest distribution is obtained for the osmotic TMAO model when used in reverse ratio.

Pre-heated dual-cured resin cements: analysis of the degree of conversion and ultimate tensile strength.

PubMed

França, Flávio Álvares; Oliveira, Michele de; Rodrigues, José Augusto; Arrais, César Augusto Galvão

2011-01-01

This study evaluated the degree of conversion (DC) and ultimate tensile strength (UTS) of dual-cured resin cements heated to 50º C prior to and during polymerization. Disc- and hourglass-shaped specimens of Rely X ARC (RX) and Variolink II (VII) were obtained using addition silicon molds. The products were manipulated at 25º C or 50º C and were subjected to 3 curing conditions: light-activation through a glass slide or through a pre-cured 2-mm thick resin composite disc, or they were allowed to self-cure (SC). All specimens were dark-stored dry for 15 days. For DC analysis, the resin cements were placed into the mold located on the center of a horizontal diamond on the attenuated total reflectance element in the optical bench of a Fourier Transformed Infrared spectrometer. Infrared spectra (n = 6) were collected between 1680 and 1500 cm-1, and DC was calculated by standard methods using changes in ratios of aliphatic-to-aromatic C=C absorption peaks from uncured and cured states. For UTS test, specimens (n = 10) were tested in tension in a universal testing machine (crosshead speed of 1 mm/min) until failure. DC and UTS data were submitted to 2-way ANOVA, followed by Tukey's test (α= 5%). Both products showed higher DC at 50º C than at 25º C in all curing conditions. No significant difference in UTS was noted between most light-activated groups at 25º C and those at 50º C. VII SC groups showed higher UTS at 50º C than at 25º C (p < 0.05). Increased temperature led to higher DC, but its effects on resin cement UTS depended on the curing condition.

Unmasked adult-onset urea cycle disorders in the critical care setting.

PubMed

Summar, Marshall L; Barr, Frederick; Dawling, Sheila; Smith, Wendy; Lee, Brendan; Singh, Rani H; Rhead, William J; Sniderman King, Lisa; Christman, Brian W

2005-10-01

Most often, urea cycle disorders have been described as acute onset hyperammonemia in the newborn period; however, there is a growing awareness that urea cycle disorders can present at almost any age, frequently in the critical care setting. This article presents three cases of adult-onset hyperammonemia caused by inherited defects in nitrogen processing in the urea cycle, and reviews the diagnosis, management, and pathophysiology of adult-onset urea cycle disorders. Individuals who have milder molecular urea cycle defects can lead a relatively normal life until a severe environmental stress triggers a hyperammonemic crisis. Comorbid conditions such as physical trauma often delay the diagnosis of the urea cycle defect. Prompt recognition and treatment are essential in determining the outcome of these patients.

Alpha-glucosidase folding during urea denaturation: enzyme kinetics and computational prediction.

PubMed

Wu, Xue-Qiang; Wang, Jun; Lü, Zhi-Rong; Tang, Hong-Min; Park, Daeui; Oh, Sang-Ho; Bhak, Jong; Shi, Long; Park, Yong-Doo; Zou, Fei

2010-03-01

In this study, we investigated structural changes in alpha-glucosidase during urea denaturation. Alpha-glucosidase was inactivated by urea in a dose-dependent manner. The inactivation was a first-order reaction with a monophase process. Urea inhibited alpha-glucosidase in a mixed-type reaction. We found that an increase in the hydrophobic surface of this enzyme induced by urea resulted in aggregation caused by unstable folding intermediates. We also simulated the docking between alpha-glucosidase and urea. The docking simulation suggested that several residues, namely THR9, TRP14, LYS15, THR287, ALA289, ASP338, SER339, and TRP340, interact with urea. Our study provides insights into the alpha-glucosidase unfolding pathway and 3D structure of alpha-glucosidase.

Improved UT1 Predictions through Low-Latency VLBI Observations

DTIC Science & Technology

2010-03-14

J Geod (2010) 84:399–402 DOI 10.1007/s00190-010-0372-8 SHORT NOTE Improved UT1 predictions through low-latency VLBI observations Brian Luzum · Axel...polar motion and nutation on UT1 determinations from VLBI Intensive obser- vations. J Geod 82(12):863. doi:10.1007/s00190-008-0212-2 Ray JR, Carter WE...Behrend D (2007) The International VLBI Service for Geodesy and Astrometry (IVS): current capabilities and future prospects. J Geod 81(6–8):479. doi

Mechanical Insight into Resistance of Betaine to Urea-Induced Protein Denaturation.

PubMed

Chen, Jiantao; Gong, Xiangjun; Zeng, Chaoxi; Wang, Yonghua; Zhang, Guangzhao

2016-12-08

It is known that urea can induce protein denaturation that can be inhibited by osmolytes. Yet, experimental explorations on this mechanism at the molecular level are still lacking. We have investigated the resistance of betaine to the urea-induced denaturation of lysozyme in aqueous solutions using low-field NMR. Our study demonstrates that urea molecules directly interact with lysozyme, leading to denaturation. However, betaine molecules interacting with urea more strongly than lysozyme can pull the bound urea molecules from lysozyme so that the protein is protected from denaturation. The number of urea molecules bound to a betaine molecule is given under different conditions. Proton NMR spectroscopy ( 1 H-NMR) and Fourier transform infrared spectroscopy reveal that the interaction between betaine and urea is through hydrogen bonding.

On the influence of the mixture of denaturants on protein structure stability: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Shao, Qiang; Wang, Jinan; Zhu, Weiliang

2014-09-01

Mixtures of osmolytes and/or inorganic salts are present in the cell. Therefore, the understanding of the interplay of mixed osmolyte molecules and inorganic salts and their combined effects on protein structure is of fundamental importance. A novel test is presented to investigate the combined effects of urea and a chaotropic inorganic salt, potassium iodide (KI), on protein structure by using molecular dynamics simulation. It is found that the coexistence of KI and urea does not affect their respective distribution in solution. The solvation of KI salt in urea solution makes the electrostatic interactions of urea more favorable, promoting the hydrogen bonding between urea (and water) to protein backbone. The interactions from K+ and hydrogen bonding from urea and water to protein backbone work as the driving force for protein denaturation. The collaborative behavior of urea and KI salt thus enhances the denaturing ability of urea and KI mixed solution.

Enhanced Right-Chamber Remodeling in Endurance Ultra-Trail Athletes Compared to Marathon Runners Detected by Standard and Speckle-Tracking Echocardiography

PubMed Central

Ujka, Kristian; Bastiani, Luca; D'Angelo, Gennaro; Catuzzo, Bruna; Tonacci, Alessandro; Mrakic-Sposta, Simona; Vezzoli, Alessandra; Giardini, Guido; Pratali, Lorenza

2017-01-01

Background: Strenuous and endurance exercise training have been associated with morphological and functional heart remodeling. Two-dimensional speckle-tracking echocardiography (STE) is a novel technique that allows an accurate quantification of global myocardium deformation. Our aim was to evaluate together left and right cardiac remodeling in different long-distance running athletes: marathon runners (42 km) (M) and endurance mountain runners (>300 Km) (UT). Methods: A total of 92 athletes (70 males, 76%) including 47 M [age 45 ± 7 years; training: 18 (9–53) years*days/week], 45 UT [age 42 ± 9, training: 30 (15–66) years*days/week] underwent conventional echocardiography and STE (Beyond Diogenes 2.0, AMID) during the agonistic season. Results: Right ventricle (RV) end-diastolic area (p = 0.026), fractional area changing (FAC) (p = 0.008) and RV global longitudinal strain (GLS) were significantly increasedin UT athletes. Furthermore, UT showed larger right atrium (RA) volume (p = 0.03), reduced RA GLS and significantly increased RA global circumferential strain (GCS) compared to M. After adjustment for age, sex, and HR as covariates, UT showed a reduced RA GLS (OR 0.907; CI 0.856–0.961) and increased RV FAC (OR 1.172; CI: 1.044–1.317) compared to M. Conclusion: Athletes enrolled in UT endurance activities showed RV and RA morphological and functional remodeling to increased preload in comparison with M runners characterized by increased RV FAC and reduced RA GLS. Follow-up studies are needed to better assess the long-term clinical impact of these modifications. 2D STE is a useful tool for investigating the deformation dynamic in different sports specialties. PMID:28790928

Counteraction of urea-induced protein denaturation by trimethylamine N-oxide: a chemical chaperone at atomic resolution.

PubMed

Bennion, Brian J; Daggett, Valerie

2004-04-27

Proteins are very sensitive to their solvent environments. Urea is a common chemical denaturant of proteins, yet some animals contain high concentrations of urea. These animals have evolved an interesting mechanism to counteract the effects of urea by using trimethylamine N-oxide (TMAO). The molecular basis for the ability of TMAO to act as a chemical chaperone remains unknown. Here, we describe molecular dynamics simulations of a small globular protein, chymotrypsin inhibitor 2, in 8 M urea and 4 M TMAO/8 M urea solutions, in addition to other control simulations, to investigate this effect at the atomic level. In 8 M urea, the protein unfolds, and urea acts in both a direct and indirect manner to achieve this effect. In contrast, introduction of 4 M TMAO counteracts the effect of urea and the protein remains well structured. TMAO makes few direct interactions with the protein. Instead, it prevents unfolding of the protein by structuring the solvent. In particular, TMAO orders the solvent and discourages it from competing with intraprotein H bonds and breaking up the hydrophobic core of the protein.

Effect of nitrogen supplementation on urea kinetics and microbial use of recycled urea in steers consuming corn-based diets.

PubMed

Brake, D W; Titgemeyer, E C; Jones, M L; Anderson, D E

2010-08-01

We studied the effects of supplementing N as distillers dried grains with solubles (DDGS) or urea to steers consuming corn-based diets. Six ruminally and duodenally cannulated steers (244 kg) were used in 2 concurrent 3 x 3 Latin squares and fed 1 of 3 corn-based diets: control (10.2% CP), urea (13.3% CP), or DDGS (14.9% CP). Periods were 14 d, with 9 d for adaptation and 5 d for collection of urine and feces. Urinary (15)N(15)N-urea enrichments, resulting from venous infusions of (15)N(15)N-urea, were used to measure urea kinetics. Dry matter intake (6.0 kg/d) was not affected by treatment, but N intake differed (99, 151, and 123 g/d for the control, DDGS, and urea treatments, respectively). Urea-N synthesis tended to be greater (P = 0.09) for DDGS (118 g/d) than for the control treatment (52 g/d), with the urea treatment (86 g/d) being intermediate. Urea-N excreted in the urine was greater (P < 0.03) for the DDGS (35 g/d) and urea treatments (29 g/d) than for the control treatment (13 g/d). Gastrointestinal entry of urea-N was not statistically different among treatments (P = 0.25), but was numerically greatest for DDGS (83 g/d), intermediate for urea (57 g/d), and least for the control (39 g/d). The amount of urea-N returned to the ornithine cycle tended to be greater (P = 0.09) for the DDGS treatment (47 g/d) than for the urea (27 g/d) or control treatment (16 g/d). The fraction of recycled urea-N that was apparently used for anabolism tended (P = 0.14) to be greater for the control treatment (0.56) than for the DDGS treatment (0.31), with the urea treatment (0.45) being intermediate, but no differences were observed among treatments in the amount of urea-N used for anabolism (P = 0.66). Urea kinetics in cattle fed grain-based diets were largely related to the amount of N consumed. The percentage of urea production that was captured by ruminal bacteria was greater (P < 0.03) for the control treatment (42%) than for the DDGS (25%) or urea treatment (22%), but the percentage of duodenal microbial N flow that was derived from recycled urea-N tended (P = 0.10) to be greater for the DDGS treatment (35%) than for the urea (22%) or control treatment (17%). Thus, ruminal microbes were more dependent on N recycling when the protein supplement was largely resistant to ruminal degradation.

A Randomized Multicenter Clinical Trial of Ultrathin Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) versus DSAEK.

PubMed

Dickman, Mor M; Kruit, Pieter J; Remeijer, Lies; van Rooij, Jeroen; Van der Lelij, Allegonda; Wijdh, Robert H J; van den Biggelaar, Frank J H M; Berendschot, Tos T J M; Nuijts, Rudy M M A

2016-11-01

To compare visual acuity, refraction, endothelial cell density (ECD), and complications after Descemet stripping automated endothelial keratoplasty (DSAEK) and ultrathin DSAEK (UT-DSAEK). A multicenter, prospective, double-masked, randomized, controlled clinical trial. From 66 patients with irreversible corneal endothelial dysfunction dues to Fuchs' dystrophy who enrolled from 4 tertiary medical centers in the Netherlands, 66 eyes were studied. Participants were centrally randomized to undergo either UT-DSAEK or DSAEK, based on preoperative best spectacle-corrected visual acuity (BSCVA), recipient central corneal thickness, patient age, and recruitment center. Donor corneas were precut by a single cornea bank. Participants underwent ophthalmic examinations preoperatively and 3, 6, and 12 months after the operation, including manifest refraction, BSCVA using an Early Treatment Diabetic Retinopathy Study chart, and endothelium imaging. BSCVA 12 months postoperatively. Preoperative BSCVA did not differ between patients undergoing DSAEK (0.35 logarithm of the minimum angle of resolution [logMAR] [95% confidence interval {CI} 0.27-0.43]; n = 32) and UT-DSAEK (0.37 logMAR [95% CI 0.31-0.43]; n = 34; P = 0.8). BSCVA was significantly better after UT-DSAEK compared with that after DSAEK at 3 months (0.17 logMAR [95% CI 0.13-0.21], n = 31 vs. 0.28 logMAR [95% CI 0.23-0.33], n = 31; P = 0.001), 6 months (0.14 logMAR [95% CI 0.10-0.18], n = 30 vs. 0.24 logMAR [95% CI 0.20-0.28], n = 30; P = 0.002), and 12 months (0.13 logMAR [95% CI 0.09-0.17], n = 33 vs. 0.20 logMAR [95% CI 0.15-0.25], n = 29; P = 0.03). Refraction, ECD loss (40% at 3 months; P < 0.001), donor loss (DSAEK n = 2 vs. UT-DSAEK n = 3 [relative risk {RR} 1.4 {95% CI 0.24-7.5}; P = 0.7]), and graft dislocation (DSAEK n = 5 vs. UT-DSAEK n = 5 [RR 1.0 {95% CI 0.34-3.33}; P = 0.9]) did not differ between UT-DSAEK and DSAEK. Donor thickness was significantly thinner for UT-DSAEK (101 μm [95% CI 93-110 μm]; range 50-145 μm) than for DSAEK (209 μm [95% CI 196-222 μm]; range 147-289 μm; P < 0.001). This study indicates that compared with DSAEK, UT-DSAEK results in faster and better recovery of BSCVA with similar refractive outcomes, endothelial cell loss, and incidence of complications. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

A study on the indirect urea dosing method in the Selective Catalytic Reduction system

NASA Astrophysics Data System (ADS)

Brzeżański, M.; Sala, R.

2016-09-01

This article presents the results of studies on concept solution of dosing urea in a gas phase in a selective catalytic reduction system. The idea of the concept was to heat-up and evaporate the water urea solution before introducing it into the exhaust gas stream. The aim was to enhance the processes of urea converting into ammonia, what is the target reductant for nitrogen oxides treatment. The study was conducted on a medium-duty Euro 5 diesel engine with exhaust line consisting of DOC catalyst, DPF filter and an SCR system with a changeable setup allowing to dose the urea in liquid phase (regular solution) and to dose it in a gas phase (concept solution). The main criteria was to assess the effect of physical state of urea dosed on the NOx conversion ratio in the SCR catalyst. In order to compare both urea dosing methods a special test procedure was developed which consisted of six test steps covering a wide temperature range of exhaust gas generated at steady state engine operation condition. Tests were conducted for different urea dosing quantities defined by the a equivalence ratio. Based on the obtained results, a remarkable improvement in NOx reduction was found for gas urea application in comparison to the standard liquid urea dosing. Measured results indicate a high potential to increase an efficiency of the SCR catalyst by using a gas phase urea and provide the basis for further scientific research on this type of concept.

Hariswaran Sitaraman | NREL

Science.gov Websites

pertaining to combustion and particulate flows. Education 2013 Ph.D., Aerospace Engineering, UT, Austin 2010 M.S., Aerospace Engineering, UT, Austin 2008 B. Tech, Aerospace Engineering, IIT Madras, Chennai

Simple Event | Center for Cancer Research

Cancer.gov

Morbi lobortis urna et posuere interdum. Fusce vulputate finibus magna et molestie. Fusce consequat, sapien a euismod vestibulum, nisl quam hendrerit quam, vitae finibus tellus orci viverra lacus. Donec condimentum purus ut fermentum egestas. Praesent tempus ligula ut ipsum tempus, eu ullamcorper arcu fringilla.

Coherent microscopic picture for urea-induced denaturation of proteins.

PubMed

Yang, Zaixing; Xiu, Peng; Shi, Biyun; Hua, Lan; Zhou, Ruhong

2012-08-02

In a previous study, we explored the mechanism of urea-induced denaturation of proteins by performing molecular dynamics (MD) simulations of hen lysozyme in 8 M urea and supported the "direct interaction mechanism" whereby urea denatures protein via dispersion interaction (Hua, L.; Zhou, R. H.; Thirumalai, D.; Berne, B. J. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 16928). Here we perform large scale MD simulations of five representative protein/peptide systems in aqueous urea to investigate if the above mechanism is common to other proteins. In all cases, accumulations of urea around proteins/peptide are observed, suggesting that urea denatures proteins by directly attacking protein backbones and side chains rather than indirectly disrupting water structure as a "water breaker". Consistent with our previous case study of lysozyme, the current energetic analyses with five protein/peptide systems reveal that urea's preferential binding to proteins mainly comes from urea's stronger dispersion interactions with proteins than with bulk solution, whereas the electrostatic (hydrogen-bonded) interactions only play a relatively minor (even negative) role during this denaturation process. Furthermore, the simulations of the peptide system at different urea concentrations (8 and 4.5 M), and with different force fields (CHARMM and OPLSAA) suggest that the above mechanism is robust, independent of the urea concentration and force field used. Last, we emphasize the importance of periodic boundary conditions in pairwise energetic analyses. This article provides a comprehensive study on the physical mechanism of urea-induced protein denaturation and suggests that the "dispersion-interaction-driven" mechanism should be general.

Interactions of urea with native and unfolded proteins: a volumetric study.

PubMed

Son, Ikbae; Shek, Yuen Lai; Tikhomirova, Anna; Baltasar, Eduardo Hidalgo; Chalikian, Tigran V

2014-11-26

We describe a statistical thermodynamic approach to analyzing urea-dependent volumetric properties of proteins. We use this approach to analyze our urea-dependent data on the partial molar volume and adiabatic compressibility of lysozyme, apocytochrome c, ribonuclease A, and α-chymotrypsinogen A. The analysis produces the thermodynamic properties of elementary urea-protein association reactions while also yielding estimates of the effective solvent-accessible surface areas of the native and unfolded protein states. Lysozyme and apocytochrome c do not undergo urea-induced transitions. The former remains folded, while the latter is unfolded between 0 and 8 M urea. In contrast, ribonuclease A and α-chymotrypsinogen A exhibit urea-induced unfolding transitions. Thus, our data permit us to characterize urea-protein interactions in both the native and unfolded states. We interpreted the urea-dependent volumetric properties of the proteins in terms of the equilibrium constant, k, and changes in volume, ΔV0, and compressibility, ΔKT0, for a reaction in which urea binds to a protein with a concomitant release of two waters of hydration to the bulk. Comparison of the values of k, ΔV0, and ΔKT0 with the similar data obtained on small molecules mimicking protein groups reveals lack of cooperative effects involved in urea-protein interactions. In general, the volumetric approach, while providing a unique characterization of cosolvent-protein interactions, offers a practical way for evaluating the effective solvent accessible surface area of biologically significant fully or partially unfolded polypeptides.

Application of total-reflection X-ray fluorescence spectrometry and high-performance liquid chromatography for the chemical characterization of xylem saps of nickel contaminated cucumber plants

NASA Astrophysics Data System (ADS)

Mihucz, Victor G.; Tatár, Eniko; Varga, Anita; Záray, Gyula; Cseh, Edit

2001-11-01

Total-reflection X-ray fluorescence (TXRF) spectrometry, reversed-phase (RP) and size-exclusion (SE) high-performance liquid chromatography (HPLC) methods were applied for the characterization of low-volume xylem sap of control and nickel contaminated cucumber plants growing in hydroponics containing urea as the sole nitrogen source. In these saps collected for 1 h, Ca, K, Fe, Mn, Ni, Zn, as well as malic, citric and fumaric acids were determined. The SEC measurements showed that macromolecules were not detectable in the samples. Nickel contamination had minimum impact on the organic acid transport, however, the transport of Zn, K and Fe was reduced by 50, 22 and 11%, respectively. This observation supports the results of our earlier experiments when nitrate ions were used as the sole nitrogen form. At the same time, the fresh root weight and the volume of the collected xylem sap increased by 36 and 85%, respectively. Therefore, nickel addition seemed to decrease the urea toxicity of the plants. By pooling the eluting fractions of the SEC column, which were 10-fold concentrated by freeze-drying, the series of the resulted samples were analyzed by the TXRF spectrometry and RP-HPLC. The three organic acids could be identified in only one of the fractions, which contained Fe and, in the case of the contaminated plants, Ni in detectable concentration. However, considerable parts of these two elements and Mn, as well as practically the total amounts of Cu may be transported by unidentified organic compounds in the xylem.

Urea-mediated protein denaturation: a consensus view.

PubMed

Das, Atanu; Mukhopadhyay, Chaitali

2009-09-24

We have performed all-atom molecular dynamics simulations of three structurally similar small globular proteins in 8 M urea and compared the results with pure aqueous simulations. Protein denaturation is preceded by an initial loss of water from the first solvation shell and consequent in-flow of urea toward the protein. Urea reaches the first solvation shell of the protein mainly due to electrostatic interaction with a considerable contribution coming from the dispersion interaction. Urea shifts the equilibrium from the native to denatured ensemble by making the protein-protein contact less stable than protein-urea contact, which is just the reverse of the condition in pure water, where protein-protein contact is more stable than protein-water contact. We have also seen that water follows urea and reaches the protein interior at later stages of denaturation, while urea preferentially and efficiently solvates different parts of the protein. Solvation of the protein backbone via hydrogen bonding, favorable electrostatic interaction with hydrophilic residues, and dispersion interaction with hydrophobic residues are the key steps through which urea intrudes the core of the protein and denatures it. Why urea is preferred over water for binding to the protein backbone and how urea orients itself toward the protein backbone have been identified comprehensively. All the key components of intermolecular forces are found to play a significant part in urea-induced protein denaturation and also toward the stability of the denatured state ensemble. Changes in water network/structure and dynamical properties and higher degree of solvation of the hydrophobic residues validate the presence of "indirect mechanism" along with the "direct mechanism" and reinforce the effect of urea on protein.

A current perspective on the compensatory effects of urea and methylamine on protein stability and function.

PubMed

Rahman, Safikur; Warepam, Marina; Singh, Laishram R; Dar, Tanveer Ali

2015-11-01

Urea is a strong denaturant and inhibits many enzymes but is accumulated intracellularly at very high concentrations (up to 3-4 M) in mammalian kidney and in many marine fishes. It is known that the harmful effects of urea on the macromolecular structure and function is offset by the accumulation of an osmolytic agent called methylamine. Intracellular concentration of urea to methylamines falls in the ratio of 2:1 to 3:2 (molar ratio). At this ratio, the thermodynamic effects of urea and methylamines on protein stability and function are believed to be algebraically additive. The mechanism of urea-methylamine counteraction has been widely investigated on various approaches including, thermodynamic, structural and functional aspects. Recent advances have also revealed atomic level insights of counteraction and various molecular dynamic simulation studies have yielded significant molecular level informations on the interaction between urea and methylamines with proteins. It is worthwhile that urea-methylamine system not only plays pivotal role for the survival and functioning of the renal medullary cells but also is a key osmoregulatory component of the marine elasmobranchs, holocephalans and coelacanths. Therefore, it is important to combine all discoveries and discuss the developments in context to physiology of the mammalian kidney and adaptation of the marine organisms. In this article we have for the first time reviewed all major developments on urea-counteraction systems to date. We have also discussed about other additional urea-counteraction systems discovered so far including urea-NaCl, urea-myoinsoitol and urea-molecular chaperone systems. Insights for the possible future research have also been highlighted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ionospheric Anomalies Related to the (M = 7.3), August 27, 2012, Puerto Earthquake, (M = 6.8), August 30, 2012 Jan Mayen Island Earthquake, and (M = 7.6), August 31, 2012, Philippines Earthquake: Two-Dimensional Principal Component Analysis

PubMed Central

Lin, Jyh-Woei

2013-01-01

Two-dimensional principal component analysis (2DPCA) and principal component analysis (PCA) are used to examine the ionospheric total electron content (TEC) data during the time period from 00:00 on August 21 to 12: 45 on August 31 (UT), which are 10 days before the M = 7.6 Philippines earthquake at 12:47:34 on August 31, 2012 (UT) with the depth at 34.9 km. From the results by using 2DPCA, a TEC precursor of Philippines earthquake is found during the time period from 4:25 to 4:40 on August 28, 2012 (UT) with the duration time of at least 15 minutes. Another earthquake-related TEC anomaly is detectable for the time period from 04:35 to 04:40 on August 27, 2012 (UT) with the duration time of at least 5 minutes during the Puerto earthquake at 04: 37:20 on August 27, 2012 (UT) (M w = 7.3) with the depth at 20.3 km. The precursor of the Puerto earthquake is not detectable. TEC anomaly is not to be found related to the Jan Mayen Island earthquake (M w = 6.8) at 13:43:24 on August 30, 2012 (UT). These earthquake-related TEC anomalies are detectable by using 2DPCA rather than PCA. They are localized nearby the epicenters of the Philippines and Puerto earthquakes. PMID:23844386