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1

Luminal Na+/H+ exchange in the proximal tubule  

PubMed Central

The proximal tubule is critical for whole-organism volume and acid–base homeostasis by reabsorbing filtered water, NaCl, bicarbonate, and citrate, as well as by excreting acid in the form of hydrogen and ammonium ions and producing new bicarbonate in the process. Filtered organic solutes such as amino acids, oligopeptides, and proteins are also retrieved by the proximal tubule. Luminal membrane Na+/H+ exchangers either directly mediate or indirectly contribute to each of these processes. Na+/H+ exchangers are a family of secondary active transporters with diverse tissue and subcellular distributions. Two isoforms, NHE3 and NHE8, are expressed at the luminal membrane of the proximal tubule. NHE3 is the prevalent isoform in adults, is the most extensively studied, and is tightly regulated by a large number of agonists and physiological conditions acting via partially defined molecular mechanisms. Comparatively little is known about NHE8, which is highly expressed at the lumen of the neonatal proximal tubule and is mostly intracellular in adults. This article discusses the physiology of proximal Na+/H+ exchange, the multiple mechanisms of NHE3 regulation, and the reciprocal relationship between NHE3 and NHE8 at the lumen of the proximal tubule.

Bobulescu, I. Alexandru

2010-01-01

2

Kinetics of Na(+) transport in necturus proximal tubule  

PubMed Central

The dependence of proximal tubular sodium and fluid readsorption on the Na(+) concentration of the luminal and peritubular fluid was studied in the perfused necturus kidney. Fluid droplets, separated by oil from the tubular contents and identical in composition to the vascular perfusate, were introduced into proximal tubules, reaspirated, and analyzed for Na(+) and [(14)C]mannitol. In addition, fluid transport was measured in short-circuited fluid samples by observing the rate of change in length of the split droplets in the tubular lumen. Both reabsorptive fluid and calculated Na fluxes were simple, storable functions of the perfusate Na(+) concentration (K(m) = 35-39 mM/liter, V(max) = 1.37 control value). Intracellular Na(+), determined by tissue analysis, and open-circuit transepithelial electrical potential differences were also saturable functions of extracellular Na(+). In contrast, net reabsorptive fluid and Na(+) fluxes were linearly dependent on intracellular Na(+) and showed no saturation, even at sharply elevated cellular sodium concentrations. These concentrations were achieved by addition of amphotericin B to the luminal perfusate, a maneuver which increased the rate of Na(+) entry into the tubule cells and caused a proportionate rise in net Na(+) flux. It is concluded that active peritubular sodium transport in proximal tubule cells of necturus is normally unsaturated and remains so even after amphotericin-induced enhancement of luminal Na(+) entry. Transepithelial movement of NaCl may be described by a model with a saturable luminal entry step of Na(+) or NaCl into the cell and a second, unsaturated active transport step of Na(+) across the peritubular cell boundary.

Spring, KR; Giebisch, G

1977-01-01

3

Ionic regulation of Na absorption in proximal colon: cation inhibition of electroneutral Na absorption  

SciTech Connect

Active Na absorption (J/sub net//sup NA/) in rabbit proximal colon in vitro is paradoxically stimulated as (Na) in the bathing media is lowered with constant osmolarity. J/sub m..-->..s//sup Na/ increases almost linearly from 0 to 50 mM (Na)/sub 0/ but then plateaus and actually decreases from 50 to 140 mM (Na)/sub 0/, consistent with inhibition of an active transport process. Both lithium and Na are equally effective inhibitors of J/sub net//sup Na/, whereas choline and mannitol do not block the high rate of J/sub net//sup Na/ observed in decreased (Na)/sub 0/. Either gluconate or proprionate replacement of Cl inhibits J/sub net//sup Na/. J/sub net//sup Na/ at lowered (Na)/sub 0/ is electrically silent and is accompanied by increased Cl absorption; it is inhibited by 10/sup -3/ M amiloride and 10/sup -3/ theophylline but not by 10/sup -4/ M bumetanide. Epinephrine is equally effective at stimulating Na absorption at 50 and 140 mM (Na). Na gradient experiments are consistent with a predominantly serosal effect of the decreased (Na)/sub 0/. These results suggest that 1) Na absorption in rabbit proximal colon in vitro is stimulated by decreased (Na); 2) the effect is cation specific, both Na and Li blocking the stimulatory effect; 3) the transport is mediated by Na-H exchange and is Cl dependent but 4) is under different regulatory mechanisms than the epinephrine-sensitive Na-Cl cotransport previously described in proximal colon. Under the appropriate conditions, proximal colon absorbs Na extremely efficiently. Na-H exchange in this epithelium is cation inhibitable, either directly or by a secondary regulatory process.

Sellin, J.H.; De Soignie, R.

1987-01-01

4

Cellular model of proximal tubule NaCl and NaHCO3 absorption  

Microsoft Academic Search

The mammalian proximal tubule absorbs 80% of bicarbonate, 50% of NaCl, and most of the organic solutes filtered at the glomerulus. The Na-K-ATPase located on the basolateral membrane generates a low intracellular [Na] and a high intracellular [K], which in conjunction with a basolateral K conductance leads to an interior negative cell voltage. These intracellular conditions provide driving forces necessary

Orson W Moe; Patricia A Preisig; Robert J Alpern

1990-01-01

5

Aldosterone regulates Na(+), K(+) ATPase activity in human renal proximal tubule cells through mineralocorticoid receptor.  

PubMed

The mechanisms by which aldosterone increases Na(+), K(+) ATPase and sodium channel activity in cortical collecting duct and distal nephron have been extensively studied. Recent investigations demonstrate that aldosterone increases Na-H exchanger-3 (NHE-3) activity, bicarbonate transport, and H(+) ATPase in proximal tubules. However, the role of aldosterone in regulation of Na(+), K(+) ATPase in proximal tubules is unknown. We hypothesize that aldosterone increases Na(+), K(+) ATPase activity in proximal tubules through activation of the mineralocorticoid receptor (MR). Immunohistochemistry of kidney sections from human, rat, and mouse kidneys revealed that the MR is expressed in the cytosol of tubules staining positively for Lotus tetragonolobus agglutinin and type IIa sodium-phosphate cotransporter (NpT2a), confirming proximal tubule localization. Adrenalectomy in Sprague-Dawley rats decreased expression of MR, ENaC ?, Na(+), K(+) ATPase ?1, and NHE-1 in all tubules, while supplementation with aldosterone restored expression of above proteins. In human kidney proximal tubule (HKC11) cells, treatment with aldosterone resulted in translocation of MR to the nucleus and phosphorylation of SGK-1. Treatment with aldosterone also increased Na(+), K(+) ATPase-mediated (86)Rb uptake and expression of Na(+), K(+) ATPase ?1 subunits in HKC11 cells. The effects of aldosterone on Na(+), K(+) ATPase-mediated (86)Rb uptake were prevented by spironolactone, a competitive inhibitor of aldosterone for the MR, and partially by Mifepristone, a glucocorticoid receptor (GR) inhibitor. These results suggest that aldosterone regulates Na(+), K(+) ATPase in renal proximal tubule cells through an MR-dependent mechanism. PMID:23684706

Salyer, Sarah A; Parks, Jason; Barati, Michelle T; Lederer, Eleanor D; Clark, Barbara J; Klein, Janet D; Khundmiri, Syed J

2013-05-16

6

Phenomenologic description of Na + , Cl ? and HCO 3 ? absorption from proximal tubules of the rat kidney  

Microsoft Academic Search

Proximal tubules of the rat kidney were perfused in vivo with NaCl-NaHCO3 Ringer's solution and the net rates of fluid absorption from Gertz shrinking drops were measured as well as the stationary electro-chemical potential differences for Na+ and Cl- that develop across the tubular wall during constant fluid absorption. By altering the rate of fluid absorption through addition of raffinose

E. Frömter; G. Rumrich; K. J. Ullrich

1973-01-01

7

Regulatory mechanisms of Na+\\/glucose cotransporters in renal proximal tubule cells  

Microsoft Academic Search

Glucose is a key fuel and an important metabolic substrate in mammals. Renal proximal tubular cells (PTCs) not only reabsorb filtered glucose but are also believed to play a role in the glucotoxicity associated with renal pathogenesis, such as in diabetes. The proximal tubule environment is where 90% of the filtered glucose is reabsorbed by the low-affinity\\/high-capacity Na+\\/glucose cotransporter 2

Y J Lee; H J Han

2007-01-01

8

Regulation of Na-Cl absorption in rabbit proximal colon in vitro  

SciTech Connect

Ion transport in rabbit proximal colon (PC) in vitro is dominated by a Na-Cl cotransport system stimulated by epinephrine. To further characterize the regulation of Na-Cl transport, the authors tested the effects of specific adrenergic agonists on ion fluxes under short-circuit conditions. Additionally, they tested the effects of the transport inhibitors bumetanide, furosemide, and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS). Basal Na and Cl absorption were essentially nil. The ..cap alpha../sub 2/-agonist clonidine significantly increased net Na and Cl absorption. The ..cap alpha../sub 1/-agonist phenylephrine and the ..beta..-agonist isoproterenol did not alter ion transport. The ..cap alpha../sub 2/-blocker yohimbine (YOH) had a complex, concentration-dependent effect. Propranolol (10/sup -5/ M) and pracozin (10/sup -6/ M) did not significantly alter either basal or stimulated ion transport. Neither bumetanide (10/sup -6/ or 10/sup -4/ M) nor furosemide (10/sup -4/ M) blocked epinephrine-stimulated Na absorption. SITS (10/sup -4/ M) and removal of mucosal K did not have a significant effect on ion transport. Conclusions: 1) Na-Cl cotransport in rabbit PC is primarily under ..cap alpha../sub 2/-adrenergic control, 2) YOH at high concentrations acts as an agonist in PC, 3) ..cap alpha../sub 2/-adrenergic agonists stimulate Na-Cl absorption in both rabbit ileum and PC. In PC, however, the process is electrically quiet and therefore does not appear to be associated with electrogenic HCO/sub 3/ secretion as found in ileum, 4) the lack of effect of bumetanide, furosemide, and 0 K on Na transport suggests that a single Na-Cl (or Na-K-2Cl) carrier is not involved in Na-Cl cotransport in proximal colon.

Sellin, J.H.; De Siognie, R.

1987-01-01

9

Dipeptidyl peptidase IV inhibition downregulates Na+ - H+ exchanger NHE3 in rat renal proximal tubule.  

PubMed

In the microvillar microdomain of the kidney brush border, sodium hydrogen exchanger type 3 (NHE3) exists in physical complexes with the serine protease dipeptidyl peptidase IV (DPPIV). The purpose of this study was to explore the functional relationship between NHE3 and DPPIV in the intact proximal tubule in vivo. To this end, male Wistar rats were treated with an injection of the reversible DPPIV inhibitor Lys [Z(NO2)]-pyrrolidide (I40; 60 mg.kg(-1).day(-1) ip) for 7 days. Rats injected with equal amounts of the noninhibitory compound Lys[Z(NO2)]-OH served as controls. Na(+) - H(+) exchange activity in isolated microvillar membrane vesicles was 45 +/- 5% decreased in rats treated with I40. Membrane fractionation studies using isopycnic centrifugation revealed that I40 provoked redistribution of NHE3 along with a small fraction of DPPIV from the apical enriched microvillar membranes to the intermicrovillar microdomain of the brush border. I40 significantly increased urine output (67 +/- 9%; P < 0.01), fractional sodium excretion (63 +/- 7%; P < 0.01), as well as lithium clearance (81 +/- 9%; P < 0.01), an index of end-proximal tubule delivery. Although not significant, a tendency toward decreased blood pressure and plasma pH/HCO(3)(-) was noted in I40-treated rats. These findings indicate that inhibition of DPPIV catalytic activity is associated with inhibition of NHE3-mediated NaHCO3 reabsorption in rat renal proximal tubule. Inhibition of apical Na(+) - H(+) exchange is due to reduced abundance of NHE3 protein in the microvillar microdomain of the kidney brush border. Moreover, this study demonstrates a physiologically significant interaction between NHE3 and DPPIV in the intact proximal tubule in vivo. PMID:18077600

Girardi, Adriana Castello Costa; Fukuda, Lívia Emy; Rossoni, Luciana Venturini; Malnic, Gerhard; Rebouças, Nancy Amaral

2007-12-12

10

How big is the electrochemical potential difference of Na + across rat renal proximal tubular cell membranes in vivo?  

Microsoft Academic Search

The intracellular Na+ concentration of surface loops of proximal tubules was measured with doublebarrelled Na+-sensitive microelectrodes in micropuncture experiments on rat kidneys in situ and in vivo. With the help of a fast recording system, it was possible to select only valid measurements, by discarding all records in which the Na+ concentration rose after the impalement presumably as a result

K. Yoshitomi; E. Frömter

1985-01-01

11

Mechanism of NaCl and water reabsorption in the proximal convoluted tubule of rat kidney.  

PubMed Central

The role of chloride concentration gradients in proximal NaCl and water reabsorption was examined in superficial proximal tubules of the rat by using perfusion and collection techniques. Reabsorptive rates (Jv), chloride concentrations, and transtubular potential difference were measured during perfusion with solutions (A) simulating an ultrafiltrate of plasma; (B) similar to (A) except that 20 meq/liter bicarbonate was replaced with acetate; (C) resembling late proximal fluid (glucose, amino acid, acetate-free, low bicarbonate, and high chloride); and (D) in which glucose and amino acids were replaced with raffinose and bicarbonate was partially replaced by poorly reabsorbable anions (cyclamate,sulfate, and methyl sulfate). In tubules perfused with solutions A and B, Jv were 2.17 and 2.7 nl mm-1 min-1 and chloride concentrations were 131.5 +/- 3.1 and 135 +/- 395 meq/liter, respectively, indicating that reabsorption is qualitatively similar to free-flow conditions and that acetate adequately replaces bicarbonate. With solution C, Jv was 2.10 nl mm-1 min-1 and potential difference was +1.5 +/- 0.2 mV, indicating that the combined presence of glucose, alanine, acetate, and bicarbonate per se is not an absolute requirement. Fluid reabsorption was virtually abolished when tubules were perfused with D solutions; Jv was not significantly different from zero despite sodium and chloride concentrations similar to plasma; chloride concentration was 110.8 +/- 0.2 meq/liter and potential difference was -0.98 mV indicating that chloride was close to electrochemical equilibrium. These results suggest the importance of the chloride gradient to proximal tubule reabsorption in regions where actively reabsorbable solutes (glucose, alanine, acetate, and bicarbonate) are lacking and provide further evidence for a passive model of NaCl and water transport.

Neumann, K H; Rector, F C

1976-01-01

12

Characteristics of NaCl and water transport in the renal proximal tubule  

PubMed Central

Renal proximal tubular transport of salt and water has been examined using isolated perfused rabbit tubules. In this method direct measurements can be made under controlled conditions not readily achieved in vivo. The results are in general agreement with previous micropuncture studies in other species, supporting the validity of both sets of measurements. In the present studies, absorption of sodium salts and water occurred without change in the concentration of Na in the lumen except when a poorly reabsorbed solute (raffinose) was present, in which case, mean concentration of Na in the lumen reached a steady-state value 33-35 mEq liter-1 less than in the bath. The tubule is very permeable to sodium salts (sodium permeability = 9.3 × 10-5 cm sec-1, ?NaCl = 0.68-(0.71) and to water (hydraulic conductivity [Lp] = 2.9 to 6.3 × 10-5 cm sec-1 atm-1). Net reabsorptive flux of Na was only 20% of the unidirectional Na flux. The steady-state concentration difference for Na in the presence of raffinose and ?NaCl in the present studies was the same as previously found by micropuncture in the rat. On the other hand Na permeability, net Na transport rate, and Lp were all from one-half to one-third as great in the isolated rabbit tubule as in the rat in vivo. Apparently, although the transport mechanisms appear to be basically the same in the two species, there are fewer transport units and passive permeability paths per unit length in the rabbit tubule than in the rat.

Kokko, Juha P.; Burg, Maurice B.; Orloff, Jack

1971-01-01

13

/sup 23/Na nuclear magnetic resonance studies of ion transport in the rabbit proximal tubule  

SciTech Connect

/sup 23/Na nuclear magnetic resonance (n.m.r.) spectroscopy was used to measure intracellular sodium levels in suspensions of rabbit proximal tubules. The intracellular sodium signal was resolved by incorporating the paramagnetic shift reagent dysprosium tripolyphosphate into the suspension buffers. This shift reagent was membrane impermeant, and induced a large upfield shift of the n.m.r. signal from the extracellular sodium pool, while leaving the intracellular pool unshifted. Tubule viability and transport characteristics were unimpaired in the presence of the shift reagent provided there was no excess tripolyphosphate, and extra calcium was added to the buffer.

Avison, M.J.

1986-01-01

14

High sodium diet and Na+-stimulated ATPase activities in basolateral plasma membranes from rat kidney proximal tubular cells.  

PubMed

The ouabain-insensitive, Na+-stimulated ATPase activity of kidney proximal tubular cells from rats fed a high Na+ diet for 4 months was increased approximately 70% when compared with control (normal diet) rats. The higher ATPase activity was not due to a change in the affinity of the system toward ATP, Mg2+ or Na+. This increase in Na+-ATPase activity may be due to either a higher number of pumps or to a higher turnover rate of the enzyme or both. The ouabain-sensitive, Na+, K+-stimulated ATPase activity, on the other hand, did not change with the high sodium diet. These results can be taken as evidence that the Na+,K+-ATPase and the Na+-ATPase of basolateral plasma membranes of proximal tubular cells from rat kidney are two different entities. PMID:3026406

Obando, M A; Marín, R; Proverbio, T; Proverbio, F

1987-01-01

15

Phosphoinositide Binding Differentially Regulates NHE1 Na+/H+ Exchanger-dependent Proximal Tubule Cell Survival*  

PubMed Central

Tubular atrophy predicts chronic kidney disease progression, and is caused by proximal tubular epithelial cell (PTC) apoptosis. The normally quiescent Na+/H+ exchanger-1 (NHE1) defends against PTC apoptosis, and is regulated by PI(4,5)P2 binding. Because of the vast array of plasma membrane lipids, we hypothesized that NHE1-mediated cell survival is dynamically regulated by multiple anionic inner leaflet phospholipids. In membrane overlay and surface plasmon resonance assays, the NHE1 C terminus bound phospholipids with low affinity and according to valence (PIP3 > PIP2 > PIP = PA > PS). NHE1-phosphoinositide binding was enhanced by acidic pH, and abolished by NHE1 Arg/Lys to Ala mutations within two juxtamembrane domains, consistent with electrostatic interactions. PI(4,5)P2-incorporated vesicles were distributed to apical and lateral PTC domains, increased NHE1-regulated Na+/H+ exchange, and blunted apoptosis, whereas NHE1 activity was decreased in cells enriched with PI(3,4,5)P3, which localized to basolateral membranes. Divergent PI(4,5)P2 and PI(3,4,5)P3 effects on NHE1-dependent Na+/H+ exchange and apoptosis were confirmed by selective phosphoinositide sequestration with pleckstrin homology domain-containing phospholipase C? and Akt peptides, PI 3-kinase, and Akt inhibition in wild-type and NHE1-null PTCs. The results reveal an on-off switch model, whereby NHE1 toggles between weak interactions with PI(4,5)P2 and PI(3,4,5)P3. In response to apoptotic stress, NHE1 is stimulated by PI(4,5)P2, which leads to PI 3-kinase activation, and PI(4,5)P2 phosphorylation. The resulting PI(3,4,5)P3 dually stimulates sustained, downstream Akt survival signaling, and dampens NHE1 activity through competitive inhibition and depletion of PI(4,5)P2.

Abu Jawdeh, Bassam G.; Khan, Shenaz; Deschenes, Isabelle; Hoshi, Malcolm; Goel, Monu; Lock, Jeffrey T.; Shinlapawittayatorn, Krekwit; Babcock, Gerald; Lakhe-Reddy, Sujata; DeCaro, Garren; Yadav, Satya P.; Mohan, Maradumane L.; Naga Prasad, Sathyamangla V.; Schilling, William P.; Ficker, Eckhard; Schelling, Jeffrey R.

2011-01-01

16

Apical and basolateral Na\\/H exchange in cultured murine proximal tubule cells (MCT): Effect of parathyroid hormone (PTH)  

Microsoft Academic Search

Kidney proximal tubule Na\\/H exchange is inhibited by PTH. To analyze further the cellular mechanisms involved in this regulation we have used MCT cells (a culture of SV-40 immortalized mouse cortical tubule cells) grown on permeant filter supports. Na\\/H exchange was measured using single cell fluorescence microscopy (BCECF) and phosphate transport (measured for comparisons) by tracer techniques. MCT cells express

Branka Mrkic; Judith Forgo; Heini Murer; Corinna Helmle-Kolb

1992-01-01

17

Na sup + -H sup + exchanger in proximal cells isolated from kidney. II. Short-term regulation by glucocorticoids  

SciTech Connect

The purpose of this study was to investigate the acute regulation by glucocorticoid of the Na{sup +}-H{sup +} exchanger in isolated renal proximal cells of the rabbit. The changes of intracellular pH (pH{sub i}) were determined in a bicarbonate-free buffer by the use of a fluorescent pH probe that may be trapped intracellularly, 2,7-biscarboxyethyl- 5(6)- carboxyfluorescein (BCECF). The activity of the Na{sup +}-H{sup +} exchanger was estimated by measuring the Na{sup +}-induced H{sup +} efflux in BCECF-loaded cells acid loaded with nigericin in choline medium. The uptake of 1.5 mM {sup 22}Na was also studied in Na{sup +}-depleted cells. Acute application of dexamethasone increased the activity of the Na{sup +}-H{sup +} exchanger. The effect on the kinetics of amiloride-sensitive Na{sup +}-H{sup +} exchange indicated that dexamethasone (DEX) increased the activity by increasing the V{sub max} of the carrier for external sodium and for external H{sup +}. The apparent affinity was not modified either for Na{sup +} or for H{sup +}. The glucocorticoid action was undetectable after pretreatment of cells with actinomycin D or cycloheximide. Acute glucocorticoid activation of the Na{sup +}-H{sup +} exchanger in isolated proximal cells required RNA and protein synthesis and was consistent with an increase in the number of carriers in the membrane.

Bidet, M.; Merot, J.; Tauc, M.; Poujeol, P. (Institut National de la Sante et de la Recherche Medicale (France))

1987-11-01

18

ATP is a coupling modulator of parallel Na,K-ATPase-K-channel activity in the renal proximal tubule.  

PubMed Central

A fundamental and essential property of nearly all salt-transporting epithelia is the tight parallel coupling between the magnitude of the K-conductive pathway at the basolateral membrane and the activity of the Na,K-dependent ATPase (Na,K-ATPase). In the present study, we demonstrate that the coupling response in the renal proximal tubule is governed, at least in part, through the interaction between ATP-sensitive K channels and Na,K-ATPase-mediated changes in intracellular ATP levels. First, we identified a K-selective channel at the basolateral membrane, which is inhibited by the cytosolic addition of ATP. Second, conventional microelectrode analysis in the isolated perfused proximal straight tubule revealed that these channels are the major determinant of the macroscopic K conductance so that ATP-mediated changes in the open probability of the K channel could alter the extent of K recycling. Indeed, the increase in the macroscopic K conductance upon stimulation of transcellular Na transport and pump activity was found to be paralleled by a decrease in intracellular ATP. Finally, a causal link between parallel Na,K-ATPase-K-channel activity and ATP was established by the finding that intracellular ATP loading uncoupled the response. With our recent observations that similar ATP-sensitive K channels are expressed abundantly in other epithelia, we postulate that ATP may act as a universal coupling modulator of parallel Na,K-ATPase-K-channel activity.

Tsuchiya, K; Wang, W; Giebisch, G; Welling, P A

1992-01-01

19

Reactive Oxygen Species Modulation of Na/K-ATPase Regulates Fibrosis and Renal Proximal Tubular Sodium Handling  

PubMed Central

The Na/K-ATPase is the primary force regulating renal sodium handling and plays a key role in both ion homeostasis and blood pressure regulation. Recently, cardiotonic steroids (CTS)-mediated Na/K-ATPase signaling has been shown to regulate fibrosis, renal proximal tubule (RPT) sodium reabsorption, and experimental Dahl salt-sensitive hypertension in response to a high-salt diet. Reactive oxygen species (ROS) are an important modulator of nephron ion transport. As there is limited knowledge regarding the role of ROS-mediated fibrosis and RPT sodium reabsorption through the Na/K-ATPase, the focus of this review is to examine the possible role of ROS in the regulation of Na/K-ATPase activity, its signaling, fibrosis, and RPT sodium reabsorption.

Liu, Jiang; Kennedy, David J.; Yan, Yanling; Shapiro, Joseph I.

2012-01-01

20

Angiotensin-(1-7) modulates the ouabain-insensitive Na+-ATPase activity from basolateral membrane of the proximal tubule.  

PubMed

Angiotensin-(1-7) (Ang-(1-7)) modulates the Na+-ATPase, but not the Na+,K+-ATPase activity present in pig kidney proximal tubules. The Na+-ATPase, insensitive to ouabain, but sensitive to furosemide, is stimulated by Ang-(1-7) (68% by 10(-9) M), in a dose-dependent manner. This effect is due to an increase in Vmax, while the apparent affinity of the enzyme for Na+ is not modified. Saralasin, a general angiotensin receptor antagonist, abolishes the stimulation, demonstrating that the Ang-(1-7) effect is mediated by receptor. The Ang-(1-7) stimulatory effect is not changed by either PD 123319, an AT2 receptor antagonist, or A779, an Ang-(1-7) receptor antagonist. On the other hand, increasing the concentration of the AT1 receptor antagonist losartan from 10(-11) to 10(-9) M, reverses the Ang(1-7) stimulation completely. A further increase to 10(-3) M losartan reverses the Na+-ATPase activity to a level similar to that obtained with Ang-(1-7) (10(-9) M) alone. The stimulatory effect of Ang-(1-7) at 10(-9) M is similar to the effect of angiotensin II (AG II) alone. However, when the two peptides are both present, Na+-ATPase activity is restored to control values. These data suggest that Ang-(1-7) selectively modulates the Na+-ATPase activity present in basolateral membranes of kidney proximal tubules through a losartan-sensitive receptor. This receptor is probably different from the receptor involved in the stimulation of the Na+-ATPase activity by angiotensin II. PMID:10930521

Caruso-Neves, C; Lara, L S; Rangel, L B; Grossi, A L; Lopes, A G

2000-07-31

21

Proximal tubule Na+/H+ exchanger activity in adult NHE8-/-, NHE3-/-, and NHE3-/-/NHE8-/- mice.  

PubMed

NHE3 is the predominant Na(+)/H(+) exchanger on the brush-border membrane (BBM) of the proximal tubule in adults. However, NHE3 null mice still have significant renal BBM Na(+)/H(+) activity. NHE8 has been localized to the BBM of proximal tubules and is more highly expressed in neonates than adult animals. The relative role of NHE8 in adult renal H(+) transport is unclear. This study examined whether there was compensation by NHE8 in NHE3(-/-) mice and by NHE3 in NHE8(-/-) mice. NHE3(-/-) mice had significant metabolic acidosis, and renal BBM NHE8 protein abundance was greater in NHE3(-/-) mice than control mice, indicating that there may be compensation by NHE8 in NHE3(-/-) mice. NHE8(-/-) mice had serum bicarbonate levels and pH that were not different from controls. NHE3 protein expression on the BBM was greater in NHE8(-/-) mice than in wild-type mice, indicating that there may be compensation by NHE3 in NHE8(-/-) mice. Both BBM NHE3 and NHE8 protein abundance increased in response to acidosis. Blood pressure and Na(+)/H(+) exchanger activity were comparable in NHE8(-/-) mice to that of controls, but both were significantly lower in NHE3(-/-) mice compared with control mice. Compared with NHE3(-/-) mice, NHE3(-/-)/NHE8(-/-) mice had lower blood pressures. While serum bicarbonate was comparable in NHE3(-/-) mice and NHE3(-/-)/NHE8(-/-) mice, proximal tubule Na(+)/H(+) exchange activity was less in NHE3(-/-)/NHE8(-/-) mice compared with NHE3(-/-) mice. In conclusion, NHE3 is the predominant Na(+)/H(+) exchanger in adult mice. NHE8 may play a compensatory role in renal acidification and blood pressure regulation in NHE3(-/-) mice. PMID:23054255

Baum, Michel; Twombley, Katherine; Gattineni, Jyothsna; Joseph, Catherine; Wang, Lin; Zhang, Qiuyu; Dwarakanath, Vangipuram; Moe, Orson W

2012-10-10

22

Na(+)-dependent and -independent amino acid transport systems in immortalized human kidney epithelial cells derived from the proximal tubule.  

PubMed

In the proximal tubule Na(+)-dependent (SDAT) and Na(+)-independent (SIAT) amino acid (AA) transporters are present. The effects of neutral, basic, and acidic AA on membrane voltage (Vm) of immortalized human kidney epithelial (IHKE-1) cells derived from the proximal tubule were examined using the slow whole-cell patch-clamp technique. In the presence of Na+ AA depolarized Vm in a concentration-dependent manner (0.05-5 mM) with Asp = Arg = Glu = 2Cys < Pro = Leu < Phe = AIB = Ala = Pro = Asn < Gly. In the absence of extracellular Na+ a decreased depolarization was seen with most neutral AA (Ala, Pro, Asn, Gly, Phe, and Leu), and the depolarization was increased with Asp, Glu, Arg, and 2Cys (1 mM each). In the absence of Na+ and a reduction in Cl- (5 mM) the depolarization by Arg was reduced. Unlike that predicted for transport by system b0,+ which exchanges neutral against dibasic amino acids, Leu does not hyperpolarize but depolarize Vm of IHKE-1 cells in the absence of extracellular Na+. After removal of Na+ (0 mM) and a reduction in Cl- (5 mM) in the extracellular solution, Leu or Glu hyperpolarized Vm, indicating that IHKE-1 cells possess two different SIAT systems, one Cl(-)-dependent and similar to system b0,+ and one novel Cl(-)-dependent system, which might be a Cl-/AA exchanger and can be blocked by the Cl(-)-channel blockers 5-nitro-2-(3-phenylpropylamino)-benzoate (10 microM) and 4,4'-diisothiocyanostibene-2,2'-disulfonic acid (50 microM). B system-related AA transporters might be responsible for the C(-)-independent SIAT, since we were able to detect its signal by Northern blot analysis. PMID:9661137

Hirsch, J R; Gonska, T; Waldegger, S; Lang, F; Schlatter, E

1998-01-01

23

Ouabain-Stimulated Trafficking Regulation of the Na/K-ATPase and NHE3 In Renal Proximal Tubule Cells  

PubMed Central

We have demonstrated that ouabain regulates protein trafficking of the Na/K-ATPase ?1 subunit and NHE3 (Na/H exchanger, isoform 3) via ouabain-activated Na/K-ATPase signaling in porcine LLC-PK1 cells. To investigate whether this mechanism is species-specific, ouabain-induced regulation of the ?1 subunit and NHE3 as well as transcellular 22Na+ transport were compared in three renal proximal tubular cell lines (human HK-2, porcine LLC-PK1, and AAC-19 originated from LLC-PK1 in which the pig ?1 was replaced by ouabain-resistant rat ?1). Ouabain inhibited transcellular 22Na+ transport due to an ouabain-induced redistribution of the ?1 subunit and NHE3. In LLC-PK1 cells, ouabain also inhibited the endocytic recycling of internalized NHE3, but has no significant effect on recycling of endocytosed ?1 subunit. These data indicated that the ouabain-induced redistribution of the ?1 subunit and NHE3 is not a species-specific phenomenon, and ouabain-activated Na/K-ATPase signaling influences NHE3 regulation.

Yan, Yanling; Haller, Steven; Shapiro, Anna; Malhotra, Nathan; Tian, Jiang; Xie, Zijian; Malhotra, Deepak; Shapiro, Joseph I.; Liu, Jiang

2012-01-01

24

Ouabain-stimulated trafficking regulation of the Na/K-ATPase and NHE3 in renal proximal tubule cells.  

PubMed

We have demonstrated that ouabain regulates protein trafficking of the Na/K-ATPase ?1 subunit and NHE3 (Na/H exchanger, isoform 3) via ouabain-activated Na/K-ATPase signaling in porcine LLC-PK1 cells. To investigate whether this mechanism is species-specific, ouabain-induced regulation of the ?1 subunit and NHE3 as well as transcellular (22)Na(+) transport were compared in three renal proximal tubular cell lines (human HK-2, porcine LLC-PK1, and AAC-19 originated from LLC-PK1 in which the pig ?1 was replaced by ouabain-resistant rat ?1). Ouabain-induced inhibition of transcellular (22)Na(+) transport is due to an ouabain-induced redistribution of the ?1 subunit and NHE3. In LLC-PK1 cells, ouabain also inhibited the endocytic recycling of internalized NHE3, but has no significant effect on recycling of endocytosed ?1 subunit. These data indicated that the ouabain-induced redistribution of the ?1 subunit and NHE3 is not a species-specific phenomenon, and ouabain-activated Na/K-ATPase signaling influences NHE3 regulation. PMID:22618525

Yan, Yanling; Haller, Steven; Shapiro, Anna; Malhotra, Nathan; Tian, Jiang; Xie, Zijian; Malhotra, Deepak; Shapiro, Joseph I; Liu, Jiang

2012-05-23

25

Proximal tubule specific knockout of the Na?/H? exchanger NHE3: effects on bicarbonate absorption and ammonium excretion.  

PubMed

The existing NHE3 knockout mouse has significant intestinal electrolyte absorption defects, making this model unsuitable for the examination of the role of proximal tubule NHE3 in pathophysiologic states in vivo. To overcome this problem, we generated proximal convoluted tubule-specific KO mice (NHE3-PT KO) by generating and crossing NHE3 floxed mice with the sodium-glucose transporter 2 Cre transgenic mice. The NHE3-PT KO mice have >80 % ablation of NHE3 as determined by immunofluorescence microscopy, western blot, and northern analyses, and show mild metabolic acidosis (serum bicarbonate of 21.2 mEq/l in KO vs. 23.7 mEq/l in WT, p?proximal convoluted tubules demonstrated a ?36 % reduction in bicarbonate reabsorption (J HCO3?=?53.52?±?4.61 pmol/min/mm in KO vs. 83.09?±?9.73 in WT) and a ?27 % reduction in volume reabsorption (J v ?=?0.67?±?0.07 nl/min/mm in KO vs. 0.92?±?0.06 nl/min/mm in WT) in mutant mice. The NHE3-PT KO mice tolerated NH4Cl acid load well (added to the drinking water) and showed NH4 excretion rates comparable to WT mice at 2 and 5 days after NH4Cl loading without disproportionate metabolic acidosis after 5 days of acid load. Our results suggest that the Na(+)/H(+) exchanger NHE3 plays an important role in fluid and bicarbonate reabsorption in the proximal convoluted tubule but does not play an important role in NH4 excretion. PMID:23508938

Li, Hong C; Du, Zhaopeng; Barone, Sharon; Rubera, Isabelle; McDonough, Alicia A; Tauc, Michel; Zahedi, Kamyar; Wang, Tong; Soleimani, Manoocher

2013-03-19

26

Immunoferritin determination of the distribution of (Na+ + K+) ATPase over the plasma membranes of renal convoluted tubules. II. Proximal segment  

PubMed Central

The distribution of (Na+ + K+) ATPase over the plasma membranes of the proximal convoluted tubule from canine renal cortex has been determined. Ultrathin frozen sections of this tissue were stained with rabbit antibodies to this enzyme and ferritin-conjugated goat antirabbit gamma-globulin. It is demonstrated that high concentrations of this enzyme uniformly line the intercellular spaces of this epithelium. The consequences of this observation are discussed in terms of the low resistant tight junctions of these tubules and the isotonic fluid transport which they support. Furthermore, antibodies to (Na+ + K+) ATPase recognize an antigen on the luminal surfaces of the tubules within the brush border. It is proposed that the enzyme is present in this region of the plasma membrane as well, although at much lower concentration. To further substantiate this conclusion, a brush border fraction has been purified from rabbit kidney and been shown to contain significant (Na+ + K+) ATPase. These results contradict earlier conclusions about the location of (Na+ + K+) ATPase in this tissue.

1976-01-01

27

Effect of treatment with electrolyzed NaCl solutions and essential oil compounds on the proximate composition, amino acid and fatty acid composition of carp fillets  

Microsoft Academic Search

This investigation was undertaken to evaluate the effect of treatment with electrolyzed NaCl solutions and 1% essential oil (0.5% carvacrol+0.5% thymol) on the proximate composition and nutritional components (amino acids and fatty acids) of carp fillets at room temperature (25°C). Carp fillet samples were treated with anodic electrolyzed NaCl solution [EW (+)], cathodic electrolyzed NaCl solution [EW (?)] followed by

Barakat S. M. Mahmoud; Y. Kawai; K. Yamazaki; K. Miyashita; T. Suzuki

2007-01-01

28

Effects of pH on kinetic parameters of the Na-HCO3 cotransporter in renal proximal tubule.  

PubMed Central

The effects of pH on cotransporter kinetics were studied in renal proximal tubule cells. Cells were grown to confluence on permeable support, mounted in an Ussing-type chamber, and permeabilized apically to small monovalent ions with amphotericin B. The steady-state, dinitrostilbene-disulfonate-sensitive current (DeltaI) was Na+ and HCO3- dependent and therefore was taken as flux through the cotransporter. When the pH of the perfusing solution was changed between 6.0 and 8.0, the conductance attributable to the cotransporter showed a maximum between pH 7.25 and pH 7.50. A similar profile was observed in the presence of a pH gradient when the pH of the apical solutions was varied between 7.0 and 8.0 (basal pH lower by 1), but not when the pH of the basal solution was varied between 7.0 and 8.0 (apical pH lower by 1 unit). To delineate the kinetic basis for these observations, DeltaI-voltage curves were obtained as a function of Na+ and HCO3- concentrations and analyzed on the basis of a kinetic cotransporter model. Increases in pH from 7.0 to 8.0 decreased the binding constants for the intracellular and extracellular substrates by a factor of 2. Furthermore, the electrical parameters that describe the interaction strength between the electric field and substrate binding or charge on the unloaded transporter increased by four- to fivefold. These data can be explained by a channel-like structure of the cotransporter, whose configuration is modified by intracellular pH such that, with increasing pH, binding of substrate to the carrier is sterically hindered but electrically facilitated.

Gross, E; Hopfer, U

1999-01-01

29

Inorganic Phosphate Modulates the Expression of the NaPi-2a Transporter in the trans-Golgi Network and the Interaction with PIST in the Proximal Tubule  

PubMed Central

Inorganic phosphate (Pi) homeostasis is maintained by the tight regulation of renal Pi excretion versus reabsorption rates that are in turn modulated by adjusting the number of Pi transporters (mainly NaPi-2a) in the proximal tubules. In response to some hormones and a high dietary Pi content, NaPi-2a is endocytosed and degraded in the lysosomes; however, we show here that some NaPi-2a molecules are targeted to the trans-Golgi network (TGN) during the endocytosis. In the TGN, NaPi-2a interacts with PIST (PDZ-domain protein interacting specifically with TC10), a TGN-resident PDZ-domain-containing protein. The extension of the interaction is proportional to the expression of NaPi-2a in the TGN, and, consistent with that, it is increased with a high Pi diet. When overexpressed in opossum kidney (OK) cells, PIST retains NaPi-2a in the TGN and inhibits Na-dependent Pi transport. Overexpression of PIST also prevents the adaptation of OK cells to a low Pi culture medium. Our data supports the view that NaPi-2a is subjected to retrograde trafficking from the plasma membrane to the TGN using one of the machineries involved in endosomal transport and explains the reported expression of NaPi-2a in the TGN.

Lanaspa, Miguel A.; Caldas, Yupanqui A.; Breusegem, Sophia Y.; Andres-Hernando, Ana; Cicerchi, Christina; Levi, Moshe; Sorribas, Victor

2013-01-01

30

Role of H(2)O(2) on the kinetics of low-affinity high-capacity Na(+)-dependent alanine transport in SHR proximal tubular epithelial cells.  

PubMed

The presence of high and low sodium affinity states for the Na(+)-dependent [(14)C]-l-alanine uptake in immortalized renal proximal tubular epithelial (PTE) cells was previously reported (Am. J. Physiol. 293 (2007) R538-R547). This study evaluated the role of H(2)O(2) on the Na(+)-dependent [(14)C]-l-alanine uptake of ASCT2 in immortalized renal PTE cells from Wistar Kyoto rat (WKY) and spontaneously hypertensive rat (SHR). Na(+) dependence of [(14)C]-l-alanine uptake was investigated replacing NaCl with an equimolar concentration of choline chloride in vehicle- and apocynin-treated cells. Na(+) removal from the uptake solution abolished transport activity in both WKY and SHR PTE cells. Decreases in H(2)O(2) levels in the extracellular medium significantly reduced Na(+)-K(m) and V(max) values of the low-affinity high-capacity component in SHR PTE cells, with no effect on the high-affinity low-capacity state of the Na(+)-dependent [(14)C]-l-alanine uptake. After removal of apocynin from the culture medium, H(2)O(2) levels returned to basal values within 1 to 3h in both WKY and SHR PTE cells and these were found stable for the next 24h. Under these experimental conditions, the Na(+)-K(m) and V(max) of the high-affinity low-capacity state were unaffected and the low-affinity high-capacity component remained significantly decreased 1day but not 4days after apocynin removal. In conclusion, H(2)O(2) in excess is required for the presence of a low-affinity high-capacity component for the Na(+)-dependent [(14)C]-l-alanine uptake in SHR PTE cells only. It is suggested that Na(+) binding in renal ASCT2 may be regulated by ROS in SHR PTE cells. PMID:20599757

Pinto, Vanda; Pinho, Maria João; Jose, Pedro A; Soares-da-Silva, Patrício

2010-07-01

31

Dopamine D3 receptor-mediated inhibition of Na+/H+ exchanger activity in normotensive and spontaneously hypertensive rat proximal tubular epithelial cells  

PubMed Central

This study evaluated the response of the Na+/H+ exchanger (NHE) to dopamine D1- and D2-like receptor stimulation in immortalized renal proximal tubular epithelial cells and freshly isolated renal proximal tubules from the spontaneously hypertensive rat (SHR) and their normotensive controls (Wistar Kyoto rats; WKY).Stimulation of D1-like receptors with SKF 38393 attenuated NHE activity in WKY cells (IC50=151 nM), but not in SHR cells. Stimulation of D2-like receptors with quinerolane (IC50=120 nM) attenuated NHE activity in SHR cells, but not in WKY cells. Forskolin was equipotent in SHR and WKY cells in inhibiting NHE activity. The effect of SKF 38393 was abolished by overnight treatment of WKY cells with cholera toxin (CTX, 500 ng ml?1), but not with pertussis toxin (PTX, 100 ng ml?1). The effect of quinerolane (1 ?M) was abolished by overnight treatment of SHR cells with PTX, but not with CTX.The D3 receptor agonist 7-OH-DPAT (IC50=0.8 ?M) attenuated NHE activity in SHR cells only. This effect was abolished by S-sulpiride and by overnight treatment with PTX. The D4 receptor agonist RBI 257 did not affect NHE activity.The 7-OH-DPAT inhibited NHE activity in freshly isolated renal proximal tubules from 4- and 12-week-old SHR and 12-week-old WKY, but not in freshly isolated renal proximal tubules from 4-week-old WKY.It is concluded that D3 receptors coupled to a Gi/o protein play a role in the handling of tubular Na+, namely through inhibition of the NHE activity, this being of particular relevance in the SHR, which fail to respond to D1-like dopamine receptor stimulation.

Pedrosa, Rui; Gomes, Pedro; Zeng, Chunyu; Hopfer, Ulrich; Jose, Pedro A; Soares-da-Silva, Patricio

2004-01-01

32

Proximate composition of Karkadeh (Hibiscus sabdariffa) seeds and some functional properties of seed protein isolate as influenced by pH and NaCl.  

PubMed

Seeds of an inbred line (B-11-90) of Karkadeh (Hibiscus sabdariffa) were investigated for their proximate composition (AOAC methods), nitrogen solubility and protein isolate (Karkadeh seed protein isolates [KSPI]) functional properties (standard methods). The fat and protein contents of the seeds were 22.43% and 32.46%, respectively. Nitrogen solubility was good in both water and 1.0 M NaCl at alkaline pH rather than at acidic pH, with better solubility at higher pH levels in water than in 1.0 M NaCl. The functional properties of the KSPI were as follows: water absorption capacity, 181 ml/100 g; fat absorption capacity, 110 ml/100 g; bulk density, 0.77 g/ml; and apparent viscosity (at 20 degrees C), 13.42 cps. KSPI showed a maximum foaming capacity at pH 12 and 1.6 M NaCl, a maximum emulsification capacity at pH 11 and 1.8 M NaCl, and a weaker foam stability at neutral pH than at acidic or alkaline pH, with a better foam stability at alkaline pH. The foam stability was considerably improved by treatment with 1.6 M NaCl. PMID:18991065

Salah, E O Mahgoub; Hayat, Z E Elbashir

2008-11-06

33

Insulin-induced Stimulation of Na+,K+-ATPase Activity in Kidney Proximal Tubule Cells Depends on Phosphorylation of the ?-Subunit at Tyr-10  

PubMed Central

Phosphorylation of the ?-subunit of Na+,K+-ATPase plays an important role in the regulation of this pump. Recent studies suggest that insulin, known to increase solute and fluid reabsorption in mammalian proximal convoluted tubule (PCT), is stimulating Na+,K+-ATPase activity through the tyrosine phosphorylation process. This study was therefore undertaken to evaluate the role of tyrosine phosphorylation of the Na+,K+-ATPase ?-subunit in the action of insulin. In rat PCT, insulin and orthovanadate (a tyrosine phosphatase inhibitor) increased tyrosine phosphorylation level of the ?-subunit more than twofold. Their effects were not additive, suggesting a common mechanism of action. Insulin-induced tyrosine phosphorylation was prevented by genistein, a tyrosine kinase inhibitor. The site of tyrosine phosphorylation was identified on Tyr-10 by controlled trypsinolysis in rat PCTs and by site-directed mutagenesis in opossum kidney cells transfected with rat ?-subunit. The functional relevance of Tyr-10 phosphorylation was assessed by 1) the abolition of insulin-induced stimulation of the ouabain-sensitive 86Rb uptake in opossum kidney cells expressing mutant rat ?1-subunits wherein tyrosine was replaced by alanine or glutamine; and 2) the similarity of the time course and dose dependency of the insulin-induced increase in ouabain-sensitive 86Rb uptake and tyrosine phosphorylation. These findings indicate that phosphorylation of the Na+,K+-ATPase ?-subunit at Tyr-10 likely participates in the physiological control of sodium reabsorption in PCT.

Feraille, Eric; Carranza, Maria Luisa; Gonin, Sandrine; Beguin, Pascal; Pedemonte, Carlos; Rousselot, Martine; Caverzasio, Joseph; Geering, Kathi; Martin, Pierre-Yves; Favre, Herve

1999-01-01

34

Proximal nephron.  

PubMed

The kidney plays a fundamental role in maintaining body salt and fluid balance and blood pressure homeostasis through the actions of its proximal and distal tubular segments of nephrons. However, proximal tubules are well recognized to exert a more prominent role than distal counterparts. Proximal tubules are responsible for reabsorbing approximately 65% of filtered load and most, if not all, of filtered amino acids, glucose, solutes, and low molecular weight proteins. Proximal tubules also play a key role in regulating acid-base balance by reabsorbing approximately 80% of filtered bicarbonate. The purpose of this review article is to provide a comprehensive overview of new insights and perspectives into current understanding of proximal tubules of nephrons, with an emphasis on the ultrastructure, molecular biology, cellular and integrative physiology, and the underlying signaling transduction mechanisms. The review is divided into three closely related sections. The first section focuses on the classification of nephrons and recent perspectives on the potential role of nephron numbers in human health and diseases. The second section reviews recent research on the structural and biochemical basis of proximal tubular function. The final section provides a comprehensive overview of new insights and perspectives in the physiological regulation of proximal tubular transport by vasoactive hormones. In the latter section, attention is particularly paid to new insights and perspectives learnt from recent cloning of transporters, development of transgenic animals with knockout or knockin of a particular gene of interest, and mapping of signaling pathways using microarrays and/or physiological proteomic approaches. PMID:23897681

Zhuo, Jia L; Li, Xiao C

2013-07-01

35

Proximal Hypospadias  

Microsoft Academic Search

Objectives: Comparative analysis of functional results, complications, cosmesis, operative time and hospital stay between staged urethroplasty and single–stage on–lay island flap for proximal hypospadias.Materials and Methods: Non–randomised single observer study of two groups of patients over a 5–year period with proximal hypospadias. Group 1 had 17 patients (mean age 17.7±1.6 months) who underwent a staged urethroplasty. Urethral plate was tubularised

M. Samuel; S. Capps; A. Worth

2001-01-01

36

Proximity fuze  

DOEpatents

A proximity fuze system includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation cirtcuit. The optical ranging apparatus includes a pulsed laser light source for generating target ranging light pulses and optical reference light pulses. A single lens directs ranging pulses to a target and collects reflected light from the target. An optical fiber bundle is used for delaying the optical reference pulses to correspond to a predetermined distance from the target. The optical ranging apparatus includes circuitry for providing a first signal depending upon the light pulses reflected from the target, a second signal depending upon the light pulses from the optical delay fiber bundle, and an output signal when the first and second signals coincide with each other. The output signal occurs when the distance from the target is equal to the predetermined distance form the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation.

Harrison, Thomas R. (Stockton, CA)

1989-08-22

37

Proximity and Localization  

Microsoft Academic Search

Torre A. and Rallet A. (2005) Proximity and localization, Regional Studies39, 47- 59. The objective of this paper is to pave the way for an analysis of the relations between proximity and localization of activities and people, two notions that are often mistaken for one another. Our method consists in exploiting the semantic wealth of the notion of proximity. We

Andre Torre; Alain Rallet

2005-01-01

38

Possible proximity of the Iridates (Na,Li)2IrO3 to a topologically ordered Mott insulator: Phase diagram of the Heisenberg-Kitaev model  

NASA Astrophysics Data System (ADS)

Motivated by the recent experimental observation of a Mott insulating state for the layered Iridates (Na,Li)2IrO3, we discuss possible ordering states of the effective Iridium moments taking into account the extreme sensitivity of these 5d transition metal oxides to crystal field effects and strong spin-orbit coupling. The microscopic exchange has been argued [1,2] to be a combination of isotropic Heisenberg and highly anisotropic Kitaev exchange, which can be tracked back to the spin and orbital components of the effective momenta. Depending on the relative strength of these two couplings, the system exhibits either various types of conventional magnetic order or a more exotic gapless spin-liquid ground state. Carefully studying [3] the stability of these phases at finite-temperatures -- and the role of frustration, i.e. a considerable suppression of the ordering temperature from the Curie-Weiss temperature -- allows us to connect back to thermodynamic experiments [4] on the Iridates (Na,Li)2IrO3 and possibly estimate microscopic coupling parameters. Finally, we discuss the effects of a magnetic field applied in the [111] direction -- perpendicular to the hexagonal lattice formed by the Iridium moments -- and show that a topologically ordered ground state is found over a small range of coupling parameters [5], also indicating the existence of an exotic critical point whose location might not be far from actual material parameters.[4pt] Work done in collaboration with H.C. Jiang, Z.C. Gu, X.L. Qi, J. Reuther, and R. Thomale.[4pt] [1] G. Jackeli and G. Khaliullin, Phys. Rev. Lett. 102, 017205 (2009). [0pt] [2] J. Chaloupka, G. Jackeli, and G. Khaliullin, Phys. Rev. Lett. 105, 027204 (2010). [0pt] [3] J. Reuther, R. Thomale, and S. Trebst, Phys. Rev. B 84, 100406(R) (2011).[0pt] [4] Y. Singh, S. Manni, and P. Gegenwart, arXiv:1106.0429[0pt] [5] H.C. Jiang, Z.C. Gu, X.L. Qi, and S. Trebst, Phys. Rev. B 83, 245104 (2011).

Trebst, Simon

2012-02-01

39

Genomic and nongenomic dose-dependent biphasic effect of aldosterone on Na+/H+ exchanger in proximal S3 segment: role of cytosolic calcium.  

PubMed

The effects of aldosterone on the intracellular pH recovery rate (pHirr) via Na+/H+ exchanger and on the [Ca2+]i were investigated in isolated rat S3 segment. Aldosterone [10(-12), 10(-10), or 10(-8) M with 1-h, 15- or 2-min preincubation (pi)] caused a dose-dependent increase in the pHirr, but aldosterone (10(-6) M with 1-h, 15- or 2-min pi) decreased it (these effects were prevented by HOE694 but not by S3226). After 1 min of aldosterone pi, there was a transient and dose-dependent increase of the [Ca2+]i and after 6-min pi there was a new increase of [Ca2+]i that persisted after 1 h. Spironolactone, actinomycin D, or cycloheximide did not affect the effects of aldosterone (15- or 2-min pi) but inhibited the effects of aldosterone (1-h pi) on pHirr and on [Ca2+]i. RU 486 prevented the stimulatory effect of aldosterone (10(-12) M, 15- or 2-min pi) on both parameters and maintained the inhibitory effect of aldosterone (10(-6) M, 15- or 2-min pi) on the pHirr but reversed its stimulatory effect on the [Ca2+]i to an inhibitory effect. The data indicate a genomic (1 h, via MR) and a nongenomic action (15 or 2 min, probably via GR) on [Ca2+]i and on the basolateral NHE1 and are compatible with stimulation of the NHE1 by increases in [Ca2+]i in the lower range (at 10(-12) M aldosterone) and inhibition by increases at high levels (at 10(-6) M aldosterone) or decreases in [Ca2+]i (at 10(-6) M aldosterone plus RU 486). PMID:18715944

Leite-Dellova, D C A; Oliveira-Souza, M; Malnic, G; Mello-Aires, M

2008-08-20

40

Proximity credentials: A survey  

SciTech Connect

Credentials as a means of identifying individuals have traditionally been a photo badge and more recently, the coded credential. Another type of badge, the proximity credential, is making inroads in the personnel identification field. This badge can be read from a distance instead of being veiewed by a guard or inserted into a reading device. This report reviews proximity credentials, identifies the companies marketing or developing proximity credentials, and describes their respective credentials. 3 tabs.

Wright, L.J.

1987-04-01

41

Neurogenic regulation of proximal bicarbonate and chloride reabsorption.  

PubMed

Although a change in renal nerve activity is known to alter proximal reabsorption, it is unclear whether reabsorption of NaHCO3 or NaCl or both are affected. Sprague-Dawley rats (n = 10) were studied using free-flow micropuncture techniques during euvolemia and following acute ipsilateral denervation. Glomerular filtration rate and single nephron glomerular filtration rate were stable. Absolute proximal bicarbonate reabsorption fell following denervation (933 +/- 40 to 817 +/- 30 pmol/min) with a parallel reduction in chloride reabsorption (1,643 +/- 116 to 1,341 +/- 129 peq/min). Urinary sodium, potassium, bicarbonate, and chloride excretion all increased significantly. To further assess the physiological significance of neurogenic modulation of proximal transport, other rats (n = 6) were subjected to acute unilateral nephrectomy (AUN). There is evidence that AUN induces a contralateral natriuresis (renorenal reflex) at least partially by causing inhibition of efferent renal nerve traffic. AUN caused significant changes in proximal NaHCO3 and NaCl reabsorption as well as in whole kidney electrolyte excretion in the same pattern as had denervation. Prior denervation of the remaining kidney prevented the proximal and whole kidney response to AUN (n = 6). In conclusion, depression of renal nerve activity inhibits both NaHCO3 and NaCl reabsorption in the rat superficial proximal convoluted tubule. The data are consistent with the hypothesis that changes in renal nerve activity modify whole kidney electrolyte excretion under physiological conditions at least partially by regulating proximal transport. PMID:3942224

Cogan, M G

1986-01-01

42

Proximal Humeral Fractures  

PubMed Central

The purpose of our study was to biomechanically compare, under cyclic loading conditions, fracture site motion, humeral head collapse, and intra-articular hardware penetration in simulated 3-part osteoporotic proximal humeral fractures stabilized with 1 of 2 locking-plate constructs. We performed fixation on simulated 3-part proximal humeral fractures in 10 pairs of cadaveric osteoporotic humeri with a Hand Innovations S3 Proximal Humerus Plate (S3 plate) or an LCP Proximal Humerus Plate (LCP plate; 1 each for each pair). The specimens were potted, mounted on a materials testing machine, and subjected to 5000 cycles of abduction in the scapular plane, loading through the supraspinatus tendon. Interfragmentary displacement at 2 virtual points (the most medial aspect of the calcar and the most superior aspect of the osteotomy line between the greater tuberosity and humeral head) was measured using an optical tracking system. Humeral head rotation was also measured. We used a generalized linear latent and mixed model to check for an effect of cyclic loading and treatment on the parameters of interest (significance, P < .05). After cyclic loading, the S3 plate humeri showed significantly greater displacement of the greater tuberosity fragment and rotation of the humeral head and a trend (not a significant difference) toward greater displacement at the calcar. No hardware penetration was noted for either repair. Although the S3 plate repairs resulted in significantly more fracture site motion, it is unknown whether the magnitude of the motion is clinically significant.

Rose, David M.; Sutter, Edward G.; Mears, Simon C.; Gupta, Rohit R.; Belkoff, Stephen M.

2010-01-01

43

Proximal ulna fractures.  

PubMed

Proximal ulna fractures are relatively common. They range in severity from a simple transverse olecranon fracture to a highly complex fracture dislocation involving a comminuted coronoid process. The anatomy, fracture pathology, treatment approach, and rehabilitation are presented in this article. PMID:19181239

Sahajpal, Deenesh; Wright, Thomas W

2009-02-01

44

XQL and Proximal Nodes.  

ERIC Educational Resources Information Center

Discussion of models that have been developed to structure text documents for information retrieval focuses on XML and its proposed query language XQL. Considers efficiency of the query engine and shows that an already existing model, Proximal Nodes, can be used as an efficient query engine behind an XQL front-end. (Author/LRW)

Baeza-Yates, Ricardo; Navarro, Gonzalo

2002-01-01

45

Proximate Analysis of Coal  

ERIC Educational Resources Information Center

|This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

Donahue, Craig J.; Rais, Elizabeth A.

2009-01-01

46

Proximal Point Methods Revisited  

NASA Astrophysics Data System (ADS)

The proximal point methods have been widely used in the last decades to approximate the solutions of nonlinear equations associated with monotone operators. Inspired by the iterative procedure defined by B. Martinet (1970), R.T. Rockafellar introduced in 1976 the so-called proximal point algorithm (PPA) for a general maximal monotone operator. The sequence generated by this iterative method is weakly convergent under appropriate conditions, but not necessarily strongly convergent, as proved by O. Güler (1991). This fact explains the introduction of different modified versions of the PPA which generate strongly convergent sequences under appropriate conditions, including the contraction-PPA defined by H.K. Xu in 2002. Here we discuss Xu's modified PPA as well as some of its generalizations. Special attention is paid to the computational errors, in particular the original Rockafellar summability assumption is replaced by the condition that the error sequence converges to zero strongly.

Boikanyo, Oganeditse A.; Moro?anu, Gheorghe

2011-09-01

47

Proximity networks and epidemics  

NASA Astrophysics Data System (ADS)

Disease spread in most biological populations requires the proximity of agents. In populations where the individuals have spatial mobility, the contact graph is generated by the “collision dynamics” of the agents, and thus the evolution of epidemics couples directly to the spatial dynamics of the population. We first briefly review the properties and the methodology of an agent-based simulation (EPISIMS) to model disease spread in realistic urban dynamic contact networks. Using the data generated by this simulation, we introduce the notion of dynamic proximity networks which takes into account the relevant time-scales for disease spread: contact duration, infectivity period, and rate of contact creation. This approach promises to be a good candidate for a unified treatment of epidemic types that are driven by agent collision dynamics. In particular, using a simple model, we show that it can account for the observed qualitative differences between the degree distributions of contact graphs of diseases with short infectivity period (such as air-transmitted diseases) or long infectivity periods (such as HIV).

Toroczkai, Zoltán; Guclu, Hasan

2007-05-01

48

Echosonography with proximity sensors  

NASA Astrophysics Data System (ADS)

We propose the use of a commercial ultrasonic proximity sensor kit for profiling an altitude-varying surface by employing echosonography. The proximity sensor kit, two identical transducers together with its dedicated operating circuit, is used as a profiler for the construction of an image. Ultrasonic pulses are emitted from one of the transducers and received by the other. The time duration between the pulses allows us to determine the traveling distance of each pulse. In the experiment, the circuit is used with the addition of two copper wires for directing the outgoing and incoming signals to an oscilloscope. The time of flight of ultrasonic pulses can thus be determined. Square grids of 5 × 5 cm2 are made from fishing lines, forming pixels in the image. The grids are designed to hold the detection unit in place, about 30 cm above a flat surface. The surface to be imaged is constructed to be height varying and placed on the flat surface underneath the grids. Our result shows that an image of the profiled surface can be created by varying the location of the detection unit along the grid. We also investigate the deviation in relation to the time of flight of the ultrasonic pulse. Such an experiment should be valuable for conveying the concept of ultrasonic imaging to physical and medical science undergraduate students. Due to its simplicity, the setup could be made in any undergraduate laboratory relatively inexpensively and it requires no complex parts. The results illustrate the concept of echosonography.

Thaisiam, W.; Laithong, T.; Meekhun, S.; Chaiwathyothin, N.; Thanlarp, P.; Danworaphong, S.

2013-03-01

49

Preserving average proximity in arrays  

Microsoft Academic Search

Programmers and data structure designers are often forced to choose between alternative structures. In storing these structures, preserving logical adjacencies or “proximity” is usually an important consideration. The combinatorial problem of storing arrays as various kinds of list structures is examined. Embeddings of graphs are used to model the loss of proximity involved in such storage schemes, and an elementary

Richard A. DeMillo; Stanley C. Eisenstat; Richard J. Lipton

1978-01-01

50

Proximity-based sentiment analysis  

Microsoft Academic Search

Sentime nt analysis seeks to characterize opinionated or evaluative aspects of natural language text thus helping people to discover valuable information from large amounts of unstructured data 111. In this paper we explore a new methodology for sentiment analysis called proximity-based sentiment analysis. We take a different approach, by considering a new set of features based on word proximities in

S. M. Shamimul Hasan; Donald A. Adjeroh

2011-01-01

51

Proximal humeral fractures: internal fixation.  

PubMed

Fractures of the proximal humerus are common injuries that are increasing in incidence as the population ages. These fractures are often treated nonsurgically; however, surgery is indicated if displacement, concurrent dislocation, or unacceptable alignment is present. Knowledge of the anatomic and physiologic characteristics of the proximal humerus and shoulder joint and familiarity with the available fixation elements will help surgeons make informed and patient-specific decisions regarding treatment. Reduction and internal fixation of proximal humeral fractures has expanding indications in comparison with arthroplasty, in part because of improvements in fixation technology and a better understanding of anatomy and physiology. The outcomes of proximal humeral fractures managed with percutaneous pinning, open reduction and locked-plate fixation, and intramedullary fixation are being actively investigated. PMID:23395021

Aaron, Daniel; Shatsky, Joshua; Paredes, Juan Carlos S; Jiang, Chunyan; Parsons, Bradford O; Flatow, Evan L

2013-01-01

52

Physiological changes in extracellular sodium directly control human proximal tubule growth and transport  

Microsoft Academic Search

In order to examine the nature and potential mechanisms of action of extracellular sodium on human proximal tubule growth\\u000a and transport, quiescent primary cultures of human proximal tubule cells (PTC) were incubated for 24 h in serum-free, growth-factor-free\\u000a culture media containing low (130 mmol\\/l), control (140 mmol\\/l) or high (150 mmol\\/l) Na+. Compared to control conditions, cells exposed to a high Na+ concentration demonstrated

David W. Johnson; Heather J. Saunders; Philip Poronnik; David I. Cook; Michael J. Field; Carol A. Pollock

1997-01-01

53

Superconducting quantum interference proximity transistor  

NASA Astrophysics Data System (ADS)

When a superconductor is placed close to a non-superconducting metal, it can induce superconducting correlations in the metal , known as the `proximity effect'. Such behaviour modifies the density of states (DOS) in the normal metal and opens a minigap with an amplitude that can be controlled by changing the phase of the superconducting order parameter. Here, we exploit such behaviour to realize a new type of interferometer, the superconducting quantum interference proximity transistor (SQUIPT), for which the operation relies on the modulation with the magnetic field of the DOS of a proximized metal embedded in a superconducting loop. Even without optimizing its design, this device shows extremely low flux noise, down to ~10-5?0Hz-1/2 (?0~=2×10-15Wb is the flux quantum) and dissipation several orders of magnitude smaller than in conventional superconducting interferometers. With optimization, the SQUIPT could significantly increase the sensitivity with which small magnetic moments are detected.

Giazotto, Francesco; Peltonen, Joonas T.; Meschke, Matthias; Pekola, Jukka P.

2010-04-01

54

Primary Kidney Proximal Tubule Cells  

PubMed Central

Summary Primary rabbit kidney epithelial cell cultures can be obtained that express renal proximal tubule functions. Toward these ends, renal proximal tubules are purified from the rabbit kidney by the method of Brendel and Meezan. To summarize, each kidney is perfused with iron oxide, which becomes associated with glomeruli. The renal cortex is sliced and homogenized to liberate nephron segments. Renal proximal tubules and glomeruli are purified by sieving. The glomeruli, covered with iron oxide, are removed using a magnet. After a brief collagenase treatment (to disrupt basement membrane), the tubules are plated in hormonally defined serum-free medium supplemented with 5 ?g/mL bovine insulin, 5 ?g/mL human transferrin, and 5 × 10?8 M hydrocortisone. After 5–6 d of incubation, confluent monolayers are obtained that possess multicellular domes, indicative of their capacity for transepithelial solute transport.

Taub, Mary

2007-01-01

55

Proximity and innovation: A critical assessment  

Microsoft Academic Search

Boschma R. A. (2005) Proximity and innovation: a critical assessment, Regional Studies39, 61-74. A key issue in economic geography is to determine the impact of geographical proximity on interactive learning and innovation. We argue that the importance of geographical proximity cannot be assessed in isolation, but should always be examined in relation to other dimensions of proximity that may provide

Ron Boschma

2005-01-01

56

Proximal bodies in hypersonic flow  

Microsoft Academic Search

Hypersonic flows involving two or more bodies travelling in close proximity to one another are encountered in several important situations. The present work seeks to explore one aspect of the resulting flow problem by investigating the forces experienced by a secondary body when it is within the domain of influence of a primary body travelling at hypersonic speeds. An analytical

STUART J. L AURENCE; R. D EITERDING

2007-01-01

57

Realities of proximity facility siting  

Microsoft Academic Search

Numerous commercial nuclear power plant sites have 2 to 3 reactors located together, and a group of Facilities with capabilities for fuel fabrication, a nuclear reactor, a storage area for spent fuel, and a maintenance area for contaminated equipment and radioactive waste storage are being designed and constructed in the US. The proximity of these facilities to each other provides

DeMott

1981-01-01

58

Amino acid transport in the renal proximal tubule  

Microsoft Academic Search

Summary.   In the kidney the proximal tubule is responsible for the uptake of amino acids. This occurs via a variety of functionally\\u000a and structurally different amino acid transporters located in the luminal and basolateral membrane. Some of these transporters\\u000a show an ion-dependence (e.g. Na+, Cl? and K+) or use an H+-gradient to drive transport. Only a few amino acid transporters

T. Gonska; J. R. Hirsch; E. Schlatter

2000-01-01

59

MODELING PROXIMAL TUBULE CELL HOMEOSTASIS: TRACKING CHANGES IN LUMINAL FLOW  

PubMed Central

During normal kidney function, there are are routinely wide swings in proximal tubule fluid flow and proportional changes in Na+ reabsorption across tubule epithelial cells. This "glomerulotubular balance" occurs in the absence of any substantial change in cell volume, and is thus a challenge to coordinate luminal membrane solute entry with peritubular membrane solute exit. In this work, linear optimal control theory is applied to generate a configuration of regulated transporters that could achieve this result. A previously developed model of rat proximal tubule epithelium is linearized about a physiologic reference condition; the approximate linear system is recast as a dynamical system; and a Riccati equation is solved to yield the optimal linear feedback that stabilizes Na+ flux, cell volume, and cell pH. The first observation is that optimal feedback control is largely consigned to three physiologic variables, cell volume, cell electrical potential, and lateral intercellular hydrostatic pressure. Parameter modulation by cell volume stabilizes cell volume; parameter modulation by electrical potential or interspace pressure act to stabilize Na+ flux and cell pH. This feedback control is utilized in a tracking problem, in which reabsorptive Na+ flux varies over a factor of two. The resulting control parameters consist of two terms, an autonomous term and a feedback term, and both terms include transporters on both luminal and peritubular cell membranes. Overall, the increase in Na+ flux is achieved with upregulation of luminal Na+/H+ exchange and Na+-glucose cotransport, with increased peritubular Na+?3HCO3? and K+ ? Cl? cotransport, and with increased Na+, K+-ATPase activity. The configuration of activated transporters emerges as testable hypothesis of the molecular basis for glomerulotubular balance. It is suggested that the autonomous control component at each cell membrane could represent the cytoskeletal effects of luminal flow.

Weinstein, Alan M.; Sontag, Eduardo D.

2009-01-01

60

Calcium sensitivity of dicarboxylate transport in cultured proximal tubule cells  

PubMed Central

Urinary citrate is an important inhibitor of calcium nephrolithiasis and is primarily determined by proximal tubule reabsorption. The major transporter to reabsorb citrate is Na+-dicarboxylate cotransporter (NaDC1), which transports dicarboxylates, including the divalent form of citrate. We previously found that opossum kidney (OK) proximal tubule cells variably express either divalent or trivalent citrate transport, depending on extracellular calcium. The present studies were performed to delineate the mechanism of the effect of calcium on citrate and succinate transport in these cells. Transport was measured using isotope uptake assays. In some studies, NaDC1 transport was studied in Xenopus oocytes, expressing either the rabbit or opossum ortholog. In the OK cell culture model, lowering extracellular calcium increased both citrate and succinate transport by more than twofold; the effect was specific in that glucose transport was not altered. Citrate and succinate were found to reciprocally inhibit transport at low extracellular calcium (<60 ?M), but not at normal calcium (1.2 mM); this mutual inhibition is consistent with dicarboxylate transport. The inhibition varied progressively at intermediate levels of extracellular calcium. In addition to changing the relative magnitude and interaction of citrate and succinate transport, decreasing calcium also increased the affinity of the transport process for various other dicarboxylates. Also, the affinity for succinate, at low concentrations of substrate, was increased by calcium removal. In contrast, in oocytes expressing NaDC1, calcium did not have a similar effect on transport, indicating that NaDC1 could not likely account for the findings in OK cells. In summary, extracellular calcium regulates constitutive citrate and succinate transport in OK proximal tubule cells, probably via a novel transport process that is not NaDC1. The calcium effect on citrate transport parallels in vivo studies that demonstrate the regulation of urinary citrate excretion with urinary calcium excretion, a process that may be important in decreasing urinary calcium stone formation.

Schiro, Faith R.; Pajor, Ana M.; Hamm, L. Lee

2011-01-01

61

Malunion of the proximal humerus.  

PubMed

Malunion of a proximal humerus fracture is difficult to manage once bone union has been achieved in a wrong position. Malunion may be encountered after conservative treatment or internal fixation of fractures, and also around a joint prosthesis. The malunion can involve the greater and lesser tuberosities, humeral head, bicipital groove, or the entire epiphysis. The nature of the malunion must be precisely characterized. Malunion can affect bone structures and the articular surface; any resulting displacements must be carefully measured. Clinical assessments will help to evaluate the functional repercussions and determine the need for correction. Radiographic imaging and CT scan guide the treatment plan. Arthroscopic surgery (acromioplasty or tuberoplasty) can be used to treat biceps tenosynovitis or impingement syndrome in cases where full correction of the malunion is not required. Corrective surgery of a metaphyseal malunion is used to realign the proximal humeral into the proper position. Tuberosity osteotomy is the main predictor for a poor outcome following secondary arthroplasty. PMID:23333124

Duparc, F

2013-01-16

62

Foot anomalies and proximal symphalangism.  

PubMed

We report the case of a 2-week-old girl born at term (by vaginal delivery and without antenatal or perinatal events) who was referred as having "bilateral talipes and bilateral proximal symphalangism of little and ring fingers." The "talipes" was atypical with marked equinus and varus, but no cavus or adductus of the midfoot. Her mother had both symphalangism (absence of proximal interphalangeal joints) of middle, ring, and little fingers bilaterally and fixed pes planus with a rigid fixed hindfoot-and these deformities had also been present from birth. The maternal grandmother was similarly affected. However, the neonatal subject has an unaffected older sibling; maternal siblings are also unaffected. The three affected people did not have other obvious musculoskeletal abnormalities. Because of the coalitions, the child's atypical talipes was managed by a modified Kite's procedure. Symphalangism-coalition syndromes may be associated with conductive deafness because of fusion of the auditory ossicles. PMID:22294466

Shaw, Lauren; McCaul, Janet; Irwin, Greg J; Huntley, James S

2012-01-31

63

Geographical proximity and scientific collaboration  

Microsoft Academic Search

Geography, economic, socio-political and language are considered to be factors that effect the level of research collaboration. However, to-date no technique has been developed to isolate the effect of geographical proximity from the other factors. This paper presents a methodology for specifically examining geographical effects on intra-national scientific collaboration. An investigation of intra-national university-university collaboration in Canada, Australia and the

J. S. Katz

1994-01-01

64

Micropower RF material proximity sensor  

DOEpatents

A level detector or proximity detector for materials capable of sensing through plastic container walls or encapsulating materials is disclosed. Thus, it can be used in corrosive environments, as well as in a wide variety of applications. An antenna has a characteristic impedance which depends on the materials in proximity to the antenna. An RF oscillator, which includes the antenna and is based on a single transistor in a Colpitt`s configuration, produces an oscillating signal. A detector is coupled to the oscillator which signals changes in the oscillating signal caused by changes in the materials in proximity to the antenna. The oscillator is turned on and off at a pulse repetition frequency with a low duty cycle to conserve power. The antenna consists of a straight monopole about one-quarter wavelength long at the nominal frequency of the oscillator. The antenna may be horizontally disposed on a container and very accurately detects the fill level within the container as the material inside the container reaches the level of the antenna. 5 figs.

McEwan, T.E.

1998-11-10

65

Proximate and polyphenolic characterization of cranberry pomace  

Technology Transfer Automated Retrieval System (TEKTRAN)

The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, and ash. Total carbohydrates were determined by the difference method. Polyphenolic ...

66

Bioelectric properties of proximal bronchiolar epithelium.  

PubMed

Distal airway epithelium is widely believed to secrete ions and liquid into the airspace, although this process has never been demonstrated in intact small airways. To determine the characteristics of active ion transport in distal airway epithelium, the effects of selective inhibitors of active Na+ absorption and Cl- secretion on the bioelectric properties of intact proximal bronchiolar epithelium were evaluated. Large bronchioles (450-1,200 microns outside diameter, 1.5-5.0 mm length) were excised from 4- to 8-wk-old pigs, cannulated with glass microcannulas, and perfused. Transepithelial potential difference (PD), short-circuit current (Isc), and resistance (Rm) were measured by cable analysis. In 14 tissues, resting PD, Isc, and Rm were -3.4 +/- 0.4 mV (lumen negative), 19.6 +/- 4.7 microA/cm2, and 255 +/- 50 omega.m2, respectively. The conductive Na+ channel blocker amiloride (10 microM) significantly (P < 0.05) reduced PD and Isc by 37 and 41% and significantly increased Rm by 23% in seven tissues. Subsequent bumetanide (10 microM), a blocker of active Cl- secretion through inhibition of Na(+)-K(+)-2Cl- cotransport, significantly reduced the amiloride-insensitive PD and Isc by 41 and 50%, whereas Rm significantly increased 15%. Because amiloride is known to induce Cl- secretion, the order of drug addition was reversed to determine the fractional contribution of active Cl- secretion to the resting PD, Isc, and Rm. In seven different bronchioles, bumetanide did not significantly affect PD, Isc, or Rm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8048545

Ballard, S T; Taylor, A E

1994-07-01

67

Idiopathic Proximal Hemimegacolon in an Adult Woman  

PubMed Central

Idiopathic proximal hemimegacolon is a disorder characterized by bowel dilatation proximal to the splenic flexure. It is a very rare and therefore a poorly understood clinical entity. This report describes a case of idiopathic proximal hemimegacolon in a 44-year-old woman. The patient suffered from 2 episodes of constipation and bowel dilatation over 4 years and was successfully treated by medical therapy.

Noh, Jung Won; Son, Seo Young; Ok, Chang Soo; Lee, Gayeon; Min, Byung-Hoon

2010-01-01

68

Proximity, Knowledge and Innovation in Peripheral Regions. On the Intersection between Geographical and Organizational Proximity  

Microsoft Academic Search

What role do various kinds of proximity play in the current and projected development of peripheral areas? In summarizing and drawing conclusions from this special issue on proximity, this paper elaborates on two core notions of proximity, geographical and organizational. It presents a framework in which the relationship between geographical and organizational proximity is conceptualized in a way that is

Arnoud Lagendijk; Anne Lorentzen

2007-01-01

69

Biomass proximate analysis using thermogravimetry.  

PubMed

This work proposes a 25 min-last thermogravimetric method as a tool to determine biomass sample's proximate analysis data (moisture, ash, volatile matter and fixed carbon contents) just by direct measure of weight changes on each sample's TG chart. Compared with international standards commonly used to that aim, TG is a faster and easier to develop technique. Obtained results were satisfactory, with AEE under 6% for moisture and volatile matter, close to 10% for fixed carbon determination and AAD of 1.6 points for ash content. PMID:23644064

García, Roberto; Pizarro, Consuelo; Lavín, Antonio G; Bueno, Julio L

2013-04-12

70

Proximal bodies in hypersonic flow  

SciTech Connect

Hypersonic flows involving two or more bodies travelling in close proximity to one another are encountered in several important situations, both natural and man-made. The present work seeks to investigate one aspect of the resulting flow problem by exploring the forces experienced by a secondary body when it is within the domain of influence of a primary body travelling at hypersonic speeds. An analytical methodology based on the blast wave analogy is developed and used to predict the secondary force coefficients for simple geometries in both two and three dimensions. When the secondary body is entirely inside the primary shocked region, the nature of the lateral force coefficient is found to depend strongly on the relative size of the two bodies. For two spheres, the methodology predicts that the secondary body will experience an exclusively attractive lateral force if the secondary diameter is larger than one-sixth the primary diameter. The analytical results are compared with those from numerical simulations and reasonable agreement is observed if an appropriate normalization for the lateral displacement is used. Results from a series of experiments in the T5 hypervelocity shock tunnel are also presented and compared with perfect-gas numerical simulations, with good agreement. A new force-measurement technique for short-duration hypersonic facilities, enabling the experimental simulation of the proximal bodies problem, is described. This technique provides two independent means of measurement, and the agreement observed between the two gives a further degree of confidence in the results obtained.

Deiterding, Ralf [ORNL; Laurence, Stuart J [California Institute of Technology, Pasadena; Hornung, Hans G [California Institute of Technology, Pasadena

2007-01-01

71

New Advances in the Study of the Proximal Point Algorithm  

NASA Astrophysics Data System (ADS)

Consider in a real Hilbert space H the inexact, Halpern-type, proximal point algorithm xn+1 = ?nu+(1-?n)J?nxn+en, n = 0,1,..., (H-PPA) where u, x?H are given points, J?n = (I+?na) for a given maximal monotone operator A, and (en) is the error sequence, under new assumptions on ?n?(0,1) and ?n?(0,1). Several strong convergence results for the H-PPA are presented under the general condition that the error sequence converges strongly to zero, thus improving the classical Rockafellar's summability condition on (||en||) that has been extensively used so far for different versions of the proximal point algorithm. Our results extend and improve some recent ones. These results can be applied to approximate minimizers of convex functionals. Convergence rate estimates are established for a sequence approximating the minimum value of such a functional.

Moro?anu, Gheorghe

2010-09-01

72

CFTR mediated chloride secretion in the avian renal proximal tubule.  

PubMed

In primary cell cultures of the avian (Gallus gallus) renal proximal tubule parathyroid hormone and cAMP activation generate a Cl(-)-dependent short circuit current (I(SC)) response, consistent with net transepithelial Cl(-) secretion. In this study we investigated the expression and physiological function of the Na-K-2Cl (NKCC) transporter and CFTR chloride channel, both associated with Cl(-) secretion in a variety of tissues, in these proximal tubule cells. Using both RT-PCR and immunoblotting approaches, we showed that NKCC and CFTR are expressed, both in proximal tubule primary cultures and in a proximal tubule fraction of non-cultured (native tissue) fragments. We also used electrophysiological methods to assess the functional contribution of NKCC and CFTR to forskolin-activated I(SC) responses in filter grown cultured monolayers. Bumetanide (10 ?M), a specific blocker of NKCC, inhibited forskolin activated I(SC) by about 40%, suggesting that basolateral uptake of Cl(-) is partially mediated by NKCC transport. In monolayers permeabilized on the basolateral side with nystatin, forskolin activated an apical Cl(-) conductance, manifested as bidirectional diffusion currents in the presence of oppositely directed Cl(-) gradients. Under these conditions the apical conductance appeared to show some bias towards apical-to-basolateral Cl(-) current. Two selective CFTR blockers, CFTR Inhibitor 172 and GlyH-101 (both at 20 ?M) inhibited the forskolin activated diffusion currents by 38-68%, with GlyH-101 having a greater effect. These data support the conclusion that avian renal proximal tubules utilize an apical CFTR Cl(-) channel to mediate cAMP-activated Cl(-) secretion. PMID:21964154

Laverty, Gary; Anttila, Ashley; Carty, Jenava; Reddy, Varudhini; Yum, Jamie; Arnason, Sighvatur S

2011-09-22

73

Dynamic Treatment of Displaced Proximal Phalangeal Fractures  

Microsoft Academic Search

We report a splint system for a protected mobilization program (termed dynamic treatment) of proximal phalangeal fractures. This program can be used for nonoperative treatment or after operative treatment. Intra-articular fractures of the proximal phalanx at the metacarpophalangeal joint were included. The custom-molded 2-component thermoplastic splint allows motion of the proximal and distal interphalangeal joints. It was developed to allow

T. Ebinger; N. Erhard; L. Kinzl; M. Mentzel

1999-01-01

74

Proximal Priority Laser Therapy: PPLT  

NASA Astrophysics Data System (ADS)

The author has, in the past, classified treatment methods for pain geometrically as point, line, two-dimensional, three-dimensional treatment and has used these over the years. However as a practitioner of western medicine, the author originally treated pain only directed at the painful site, and encountered cases where local treatment did not suffice. The author proved with SPECT and the Rand Phantom that treating the neck which is the midpoint of the brain, the center of the nervous system and the heart, the center of circulation, increased cerebral blood flow and also that laser emitted to neck will reach the spinal chord no matter from where on the neck the laser is emitted. From such research and 25 years of clinical experience, the author has created an anatomy based, systemic treatment method called the Proximal Priority Laser Therapy (PPLT) where not only the cerebral cortex, spinal chord and peripheral nerves are treated but also the tracts of blood vessels and lymph ducts are treated as well. Treatment method and cases are presented herein.

Ohshiro, Toshio

2004-09-01

75

Reactive grasping using optical proximity sensors  

Microsoft Academic Search

We propose a system for improving grasping using fingertip optical proximity sensors that allows us to perform online grasp adjustments to an initial grasp point without requiring premature object contact or regrasping strategies. We present novel optical proximity sensors that fit inside the fingertips of a Barrett Hand, and demonstrate their use alongside a probabilistic model for robustly combining sensor

Kaijen Hsiao; Paul Nangeroni; Manfred Huber; Ashutosh Saxena; Andrew Y. Ng

2009-01-01

76

Rheogenic sodium-bicarbonate cotransport in the peritubular cell membrane of rat renal proximal tubule  

Microsoft Academic Search

The mechanism of bicarbonate transport across the peritubular cell membrane was investigated in rat kidney proximal tubules in situ by measuring cell pH and cell Na+ activity in response to sudden reduction of peritubular Na+ and\\/or HCO3-. The following observations were made: 1. sudden peritubular reduction of either ion concentration produced the same transient depolarizing potential response; 2. bicarbonate efflux

K. Yoshitomi; B.-Ch. Burckhardt; E. Frömter

1985-01-01

77

Inorganic fluoride. Divergent effects on human proximal tubular cell viability.  

PubMed Central

Fluoride (F) is a widely distributed nephrotoxin with exposure potentially resulting from environmental pollution and from fluorinated anesthetic use (eg, isoflurane). This study sought to characterize some of the subcellular determinants of fluoride cytotoxicity and to determine whether subtoxic F exposure affects tubular cell vulnerability to superimposed ATP depletion and nephrotoxic attack. Human proximal tubular cells (HK-2) were cultured with differing amounts of NaF (0 to 20 mmol/L, overlapping with clinically relevant intrarenal/urinary levels after fluorinated anesthetic use). After completing 24-hour exposures, cell injury was determined (vital dye uptake). Fluoride effects on cell deacylation ([3]H-C20:4 release) and PLA2 activity were also assessed. To determine whether subtoxic F exposure alters tubular cell susceptibility to superimposed injury, cells were exposed to subtoxic NaF doses for 0 to 24 hours and then challenged with simulated ischemia (ATP depletion plus Ca2+ overload) or a clinically relevant nephrotoxic insult (myoglobin exposure). NaF induced dose-dependent cytotoxicity (up to approximately 90% vital dye uptake and increased [3H]C20:4 release). Extracellular Ca2+ chelation (EGTA) and PLA2 inhibitor therapy (aristolochic acid, dibucaine, or mepacrine) each conferred significant protective effects. When subtoxic NaF doses were applied, partial cytosolic PLA2 depletion rapidly developed (approximately 85% within 3 hours, determined on cell extracts). These partially PLA2-depleted cells were markedly resistant to ATP depletion/Ca2+ ionophore injury and to myoglobin-induced attack (approximately 50% decrease in cell death). We conclude that 1) F induces dose-dependent cytotoxicity in cultured human proximal tubular cells, 2) this occurs, in part, via Ca(2+)- and PLA2-dependent mechanism(s), 3) partial cytosolic PLA2 depletion subsequently results, and 4) subtoxic fluoride exposure can acutely increase cell resistance to further attack. Reductions in cytosolic PLA2 activity could potentially contribute to this result.

Zager, R. A.; Iwata, M.

1997-01-01

78

Anti-embolism stockings and proximal indentation.  

PubMed

The authors of this study noticed that the elastic garters of below knee anti-embolism stockings (AES) were indenting the proximal calves of patients after application and feared this might be interrupting venous return. This was lower on one ward which had a rigorous standardized protocol for sizing and checking stockings. Hypotheses were that proximal indentation caused higher proximal than distal pressures (reverse gradients) and that by adopting the standardized protocol throughout the unit, proximal indentation could be reduced. Fifty-seven patients were recruited after total hip replacement (THR) or total knee replacement (TKR) in a regional orthopaedic centre. The authors implemented the standardized protocol for sizing stockings and measured the pressures under them. After implementation of the standardized protocol, proximal indentation fell from 53% to 19% (p<0.05), incorrectly sized stockings from 74% to 34% (p<0.05) and removal of stockings by patients from 32% to 0% (p<0.05). In total, 21% of patients had reverse gradients which occurred in 41% of legs with proximal indentation and 8% without. When reverse gradients or proximal indentation exist, AES may not be as effective and may be counterproductive. A standardized protocol of nursing practice is critical to optimizing AES after THR and TKR. More in-vivo research is needed on AES after hip and knee replacement. PMID:22241490

Thompson, Alice; Walter, Sophie; Brunton, Luke R; Pickering, Greg T; Mehendale, Sanchit; Smith, Alison J; Bannister, Gordon C

79

Generalization of the proximity force theorem  

SciTech Connect

We generalize the Proximity Force Theorem of J. Blocki et al. (Ann. Phys. (N. Y.) 105 (1977), 427) (valid for gently curved surfaces) to include surfaces that may have large curvatures (but are still characterized by small angles between relevant portions of the interacting surfaces). A general proof is given for the approximate concinuity of the proximity force when a gap configuration goes over into a crevice after contact. Simple and somewhat improved formulae are given for the universal proximity potential functions Phi and Phi-circumflex for gaps and crevices.

Blocki, J.; Swiatecki, W.J.

1981-03-01

80

Bilateral Endoprosthetic Replacements of the Proximal Femur  

PubMed Central

Patient. We report the case of a 20-year-old caucasian male with an Ewing's sarcoma in the left upper femur. After induction chemotherapy, he underwent resection of the left upper femur and insertion of a cemented proximal femoral replacement. Four years later, he presented with a solitary bone metastasis in the right upper femur. He underwent further chemotherapy followed by resection and endoprosthetic replacement of the other proximal femur. He remains disease free with excellent function almost a year after the second operation. Discussion. We believe this is the first reported case of bilateral proximal femoral endoprostheses.

Grimer, Robert J.

1998-01-01

81

Promoting proximal formative assessment with relational discourse  

NSDL National Science Digital Library

The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

Scherr, Rachel E.; Close, Hunter G.; Mckagan, Sarah B.

2012-05-15

82

Proximity effects of superconducting multilayer film  

SciTech Connect

The proximity effects of superconducting multilayer films composed of different metals are considered. The relationship between the critical temperature of a superconducting multilayer film with strong heterogeneity and its geometric structure is given.

Xueyu, C.; Daole, Y.

1984-07-01

83

Proximity: Location, Time, and Opportunity to Communicate.  

National Technical Information Service (NTIS)

Traditional measures of proximity all share three common weaknesses: (1) they are based upon ratio-level measurement of physical distance that may not correspond to 'psychological distance,' (2) they measure distance as a fixed rather than a variable quan...

P. R. Monge K. K. Kirste

1975-01-01

84

Sodium Flux in Necturus Proximal Tubule under Voltage Clamp  

PubMed Central

Na transport and electrical properties of Necturus renal proximal tubules were analyzed, in vivo, by a voltage clamp method which utilizes an axial electrode in the tubule lumen for passage of current and simultaneous determination of net fluid (or Na) flux by the split droplet method. When the average spontaneous transepithelial potential difference of –8 mv (lumen negative) was reduced to zero by current passage, net Na flux doubled from a mean of 107 to 227 pmoles/cm2 per sec. The relationship between flux and potential over the range –25 to +10 mv was nonlinear, with flux equilibrium at –15 mv and droplet expansion at more negative values. Calculated Na permeability at flux equilibrium was 7.0 x 10–6 cm/sec. Voltage transients, similar to those caused by intraepithelial unstirred layers, were observed at the end of clamping periods. Tubular electrical resistance measured by brief square or triangle wave pulses (<100 msec) averaged 43 ohm cm2. The epithelial current-voltage relationship was linear over the range –100 to +100 mv, but displayed marked hysteresis during low frequency (<0.04 Hz) triangle wave clamps. The low transepithelial resistance and large opposing unidirectional ion fluxes suggest that passive ionic movements occur across extracellular shunt pathways, while the voltage transients and current-voltage hysteresis are consistent with the development of a local osmotic gradient within epithelium.

Spring, Kenneth R.; Paganelli, Charles V.

1972-01-01

85

A Brief Index for Proximity Searching  

Microsoft Academic Search

Many pattern recognition tasks can be modeled as proximity searching. Here the common task is to quickly find all the elements\\u000a close to a given query without sequentially scanning a very large database.\\u000a \\u000a A recent shift in the searching paradigm has been established by using permutations instead of distances to predict proximity. Every object in the database record how the

Eric Sadit Tellez; Edgar Chávez; Antonio Camarena-ibarrola

2009-01-01

86

Proximity operations for space stations and platforms  

NASA Astrophysics Data System (ADS)

The present study is concerned with concepts, techniques, and system requirements which would permit 'automated' proximity operations utilizing an unmanned vehicle such as the proposed Orbital Maneuvering Vehicle (OMV). Attention is given to proximity operations mission phases, tethered operations, operational control zones, operation control zone objectives, operational control zone definition, aspects of monitoring and tracking, the departure zone, the rendezvous zone, and coorbiting satellite zones.

Lineberry, E. C., Jr.

1984-10-01

87

The developmental spectrum of proximal radioulnar synostosis  

Microsoft Academic Search

Objective  Proximal radioulnar synostosis is a rare upper limb malformation. The elbow is first identifiable at 35 days (after conception),\\u000a at which stage the cartilaginous anlagen of the humerus, radius and ulna are continuous. Subsequently, longitudinal segmentation\\u000a produces separation of the distal radius and ulna. However, temporarily, the proximal ends are united and continue to share\\u000a a common perichondrium. We investigated the

Alison M. Elliott; Lisa Kibria; Martin H. Reed

2010-01-01

88

[Four family members with proximal myotonic myopathy  

Microsoft Academic Search

A 41-year-old woman had a 15-year history of pain in her thighs and arms, which also became weaker, and a decrease in visual acuity. Her 35-year-old brother, their 38-year-old sister and their 64-year-old mother also had myalgia, myotonia and proximal muscle weakness, and the women also had cataracts. Additional examinations and tests led to a diagnosis of proximal myotonic myopathy

A. A. Tieleman; M. P. van der Velden; M. C. Visser; J. H. J. Wokke; H. Scheffer; B. G. M. van Engelen

2004-01-01

89

A proximate perspective on reciprocal altruism  

Microsoft Academic Search

The study of reciprocal altruism, or the exchange of goods and services between individuals, requires attention to both evolutionary\\u000a explanations and proximate mechanisms. Evolutionary explanations have been debated at length, but far less is known about\\u000a the proximate mechanisms of reciprocity. Our own research has focused on the immediate causes and contingencies underlying\\u000a services such as food sharing, grooming, and

Sarah F. Brosnan; Frans B. M. de Waal

2002-01-01

90

Polarization proximity effect in isolator crystal pairs.  

PubMed

We experimentally study the polarization dynamics (orientation and ellipticity) of near-infrared light transmitted through magneto-optical yttrium iron garnet isolator crystal pairs using a modified balanced detection scheme. When the pair separation is in the submillimeter range, we observed a proximity effect in which the saturation field is reduced by up to 20%. One-dimensional calculations suggest that the proximity effect originates from magnetostatic interactions between the dipole moments of the isolator crystals. PMID:19037456

Linzon, Y; Ferrera, M; Razzari, L; Pignolet, A; Morandotti, R

2008-12-01

91

Proximity operations considerations affecting spacecraft design  

NASA Astrophysics Data System (ADS)

Experience from several recent spacecraft development programs, such as Space Station Freedom (SSF) and the Orbital Maneuvering Vehicle (OMV) has shown the need for factoring proximity operations considerations into the vehicle design process. Proximity operations, those orbital maneuvers and procedures which involve operation of two or more spacecraft at ranges of less than one nautical mile, are essential to the construction, servicing, and operation of complex spacecraft. Typical proximity operations considerations which drive spacecraft design may be broken into two broad categories; flight profile characteristics and concerns, and use of various spacecraft systems during proximity operations. Proximity operations flight profile concerns include the following: (1) relative approach/separation line; (2) relative orientation of the vehicles; (3) relative translational and rotational rates; (4) vehicle interaction, in the form of thruster plume impingement, mating or demating operations, or uncontrolled contact/collision; and (5) active vehicle piloting. Spacecraft systems used during proximity operations include the following: (1) sensors, such as radar, laser ranging devices, or optical ranging systems; (2) effector hardware, such as thrusters; (3) flight control software; and (4) mating hardware, needed for docking or berthing operations. A discussion of how these factors affect vehicle design follows, addressing both active and passive/cooperative vehicles.

Staas, Steven K.

92

Proximal segment displacement in mandibular distraction osteogenesis.  

PubMed

Distraction osteogenesis has been advocated for treatment of the mandibular deformity in patients with hemifacial microsomia (HFM). During the active phase, the force of distraction pushes the distal segment of the mandible down, creating a distraction gap. Because of the abnormal temporomandibular joint anatomy in HFM patients, the proximal segment may not seat in the glenoid fossa and thus may be displaced with distraction. The purpose of this study was to determine the vector(s) of proximal segment movement during mandibular distraction using a semiburied device. Two investigators traced the immediate pre-and postdistraction panoramic radiographs of 12 HFM patients (mean age at operation = 8.4 years, mean distraction = 28 mm) who had mandibular distraction with a semiburied device. Radiographic analysis, based on a vertical maxillary reference line, measured change in condylar position with angular and linear measurements. Inter-rater reliability for the tracing and analysis was shown with a correlation coefficient between 0.89 and 0.99 for all measures. Based on the angular and linear measurements, 10 of the 12 patients had superior movement of the proximal segment with distraction. Sagittal movement of the proximal segment could not be judged adequately. This study was based on measurements made on panoramic radiographs. Direct measurements could not be made; thus, it was not possible to estimate proximal segment movement in millimeters or as a percentage of total movement. Further studies to document proximal segment movement using computed tomography scans may provide more quantitative data. PMID:12000889

Padwa, Bonnie L; Zaragoza, Sandra M; Sonis, Andrew L

2002-03-01

93

Proximity sensor system development. CRADA final report  

SciTech Connect

Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors.

Haley, D.C. [Oak Ridge National Lab., TN (United States); Pigoski, T.M. [Merrit Systems, Inc. (United States)

1998-01-01

94

Proximity to roadways and pregnancy outcomes.  

PubMed

Adverse birth outcomes are associated with exposure to air pollution during pregnancy. Road proximity is a simple, widely available metric for capturing local variation in exposure to traffic-related air pollution. We characterized maternal exposure to traffic-related air pollution during pregnancy using residential proximity to major roadways among 2004-2008 singleton births in NC. Controlling for maternal race, age, education, nativity, marital status, and tobacco use, and season of birth, parity, infant sex, and Census tract-level urbanization and income, we evaluated the association between road proximity and pregnancy outcomes using generalized linear mixed models with a random intercept for each Census tract. Birth weight, birth weight percentile for gestational age, gestational hypertension, and small-for-gestational age were not associated with road proximity; however, women residing within 250?m of a major roadway were at 3-5% increased odds of low birth weight, preterm birth, and late preterm birth compared with women residing beyond 250?m (P<0.05). Our analyses demonstrate an association between proximity to major roadways and pregnancy outcomes using a large sample. Road proximity may represent a relatively straightforward method for assessing maternal risk from exposure to traffic-related air pollution, with results offering guidance for studies that can more accurately characterize air pollution exposures. PMID:22805991

Miranda, Marie Lynn; Edwards, Sharon E; Chang, Howard H; Auten, Richard L

2012-07-18

95

Effect of a high NaCl diet on the active mechanisms of Na+ extrusion in rat kidney.  

PubMed

Healthy male rats were exposed to a chronic ingesta of an isotonic NaCl solution during a period of four months. Two different preparations were utilized to study the effect of this treatment on the active mechanisms of Na+ reabsorption of kidney proximal tubular cells: outermost kidney cortex slices (rich in proximal tubules) and inside-out basolateral plasma membrane vesicles prepared from the same tissue. It was found that the activity of the ouabain-insensitive, Na-pump of basolateral plasma membranes of kidney proximal tubular cells was increased in about 70%, whereas the ouabain-sensitive, Na,K-pump activity did not change with the experimental treatment. These results represent a strong support to the two Na-pump's hypothesis since the treatment affected the Na-pump differentially without affecting the Na,K-pump. PMID:2431190

Marín, R; Obando, M A; Proverbio, T; Proverbio, F

1986-10-01

96

Proximity Congruency and Proximity Incongruency: Factors Affecting the State of the Art of Environmental Education.  

ERIC Educational Resources Information Center

|This paper presents arguments for the premise that, from an instructional point of view, the most effective environmental education program is one that provides for proximity congruency (direct interaction with the natural and man-made environment) as opposed to proximity incongruency. The author suggests that if the teacher is interested in…

Peters, Richard

97

Development and characterization of rabbit proximal tubular epithelial cell lines  

Microsoft Academic Search

Development and characterization of rabbit proximal tubular epithelial cell lines. We have isolated rabbit kidney proximal tubular epithelial cell lines. The selection was based on their ability to form confluent monolayers on porous supports and to maintain receptor-mediated signal transduction and ion transport, characteristic of the proximal tubule. The isolation method consisted of several steps: (1) superficial cortical proximal tubule

Michael F Romero; Janice G Douglas; Richard L Eckert; Ulrich Hopfer; James W Jacobberger

1992-01-01

98

The geographical and institutional proximity of research collaboration  

Microsoft Academic Search

Collaboration and the exchange of knowledge are supposedly made easier by geographical proximity because of the tacit character of knowledge. Recently a number of scholars' criticised this view on geographical proximity as being oversimplified and argued that the precise role of geographical proximity for knowledge exchange and collaboration still remains unclear. This paper analyses the role of geographical proximity for

Roderik Ponds; Frank van Oort; Koen Frenken

2007-01-01

99

Knowledge networks in the Dutch aviation industry: the proximity paradox  

Microsoft Academic Search

The importance of geographical proximity for interaction and knowledge sharing has been discussed extensively in economic geography in recent years. There is increasing consensus that it is just one out of many types of proximities that might be relevant. We argue that proximity may be a crucial driver for agents to connect and exchange knowledge, but too much proximity between

Tom Broekel; Ron Boschma

2009-01-01

100

Streaming potentials and diffusion potentials across rabbit proximal convoluted tubule.  

PubMed

The streaming potential, defined as the transepithelial potential appearing in the presence of an osmotic water flow, was measured in rabbit kidney proximal convoluted tubules perfused in vitro. The S2 segments studied were dissected from mid-cortical and juxtamedullary portions of the kidney and the streaming potential induced by the addition of raffinose in bath was compared for each tubule with the diffusion potential corresponding to an imposed NaCl gradient in the absence of osmotic gradient. The amplitude of the measured streaming potential was found to vary from positive to negative values (+0.9 to -1.8 mV) according to the location of the dissected tubule: the more juxtamedullary the nephron, the more lumen negative was the streaming potential. This correlated well with the diffusion potentials recorded on the same tubules and the amplitude of the streaming potentials was a close function of the PNa/PCl ratios calculated from these diffusion potentials. This is in agreement with the hypothesis of solute polarization in an unstirred layer as the origin of the streaming potential; a calculation of hydraulic permeability (Pf) of the proximal tubule, taking the role of such an unstirred layer into consideration is proposed. PMID:3982966

Corman, B

1985-02-01

101

Process solutions for the global proximity effect on submicron lithography  

NASA Astrophysics Data System (ADS)

Proximity effect, in general, is a major concern for submicron lithography. There are two kinds of proximity effects -- global and local -- normally observed in the submicron lithography processes. Local proximity effect occurs as a result of interaction between adjacent patterns, in which elbow rounding and proximity effect between adjacent contact holes are two typical examples. Global proximity effect is a result of thin film interference of photoresist thickness variation over topography. The critical dimension variation between cell array and periphery patterns is a typical case. In this paper we discuss several process approaches to the solution of global proximity effect. An optimum process to minimize the global proximity effect is described.

Lee, Daniel H.; Chu, Ron

1992-06-01

102

Understanding illumination effects for control of optical proximity effects (OPE)  

NASA Astrophysics Data System (ADS)

Optical lithography has had great success in recent history in utilizing the most advanced optical technology to create NA=1.35 immersion lenses. These lenses have aberration levels at or below the 5m level. Much of this is due to advancements in lens design, materials, and aspheric polishing techniques. Now that the lenses are nearly "perfect", more attention is being given to the illuminator and its performance. This paper examines the fundamental metrics that are used to analyze the illumination source shape as it pertains to the optical proximity effect (OPE). It is found that the more traditional metric of partial coherence, ?, is often not sufficient to explain through pitch CD performance. Metrics are introduced to compare multiple sources and compared to their correlation to OPE with respect to a reference. A new parametric model for annular illumination is introduced and shown to correlate within an RMS=0.03nm of the OPE data.

Flagello, Donis G.; Geh, Bernd; Socha, Robert; Liu, Peng; Cao, Yu; Stas, Roland; Natt, Oliver; Zimmermann, Jörg

2008-03-01

103

Klotho: a novel phosphaturic substance acting as an autocrine enzyme in the renal proximal tubule  

PubMed Central

Klotho has profound effects on phosphate metabolism, but the mechanisms of how Klotho affects phosphate homeostasis is unknown. We detected Klotho in the proximal tubule cell, brush border, and urinary lumen, where phosphate homeostasis resides. Increasing Klotho in the kidney and urine chronically by transgenic overexpression or acutely by intravenous infusion caused hypophosphatemia, phosphaturia from decreased proximal phosphate reabsorption, and decreased activity and protein of the principal renal phosphate transporter NaPi-2a. The phosphaturic effect was present in FGF23-null mice, indicating a direct action distinct from Klotho’s known role as a coreceptor for FGF23. Direct inhibition of NaPi-2a by Klotho was confirmed in cultured cells and in cell-free membrane vesicles characterized by acute inhibition of transport activity followed by decreased cell surface protein. Transport inhibition can be mimicked by recombinant ?-glucuronidase and is associated with proteolytic degradation and reduced surface NaPi-2a. The inhibitory effect of Klotho on NaPi-2a was blocked by ?-glucuronidase inhibitor but not by protease inhibitor. Klotho is a novel phosphaturic substance that acts as an enzyme in the proximal tubule urinary lumen by modifying glycans, which cause decreased transporter activity, followed by proteolytic degradation and possibly internalization of NaPi-2a from the apical membrane.—Hu, M. C., Shi, M., Zhang, J., Pastor, J., Nakatani, T., Lanske, B., Shawkat Razzaque, M., Rosenblatt, K. P., Baum, M. G., Kuro-o, M., Moe, O. W. Klotho: a novel phosphaturic substance acting as an autocrine enzyme in the renal proximal tubule.

Hu, Ming Chang; Shi, Mingjun; Zhang, Jianning; Pastor, Johanne; Nakatani, Teruyo; Lanske, Beate; Razzaque, M. Shawkat; Rosenblatt, Kevin P.; Baum, Michel G.; Kuro-o, Makoto; Moe, Orson W.

2010-01-01

104

Estrogen downregulates the proximal tubule type IIa sodium phosphate cotransporter causing phosphate wasting and hypophosphatemia  

PubMed Central

Estrogen treatment causes significant hypophosphatemia in patients. To determine the mechanisms responsible for this effect, we injected ovariectomized rats with either 17?-estradiol or vehicle for three days. Significant renal phosphate wasting and hypophosphatemia occurred in estrogen-treated rats despite a decrease in their food intake. The mRNA and protein levels of the renal proximal tubule sodium phosphate cotransporter (NaPi-IIa) were significantly decreased in estradiol-treated ad-libitum or pair-fed groups. Estrogen did not affect NaPi-III or NaPi-IIc expression. In ovariectomized and parathyroidectomized rats, 17?-estradiol caused a significant decrease in NaPi-IIa mRNA and protein expression compared to vehicle. Estrogen receptor alpha isoform blocker significantly blunted the anorexic effect of 17?-estradiol but did not affect the downregulation of NaPi-IIa. Our studies show that renal phosphate wasting and hypophosphatemia induced by estrogen are secondary to downregulation of NaPi-IIa in the proximal tubule. These effects are independent of food intake or parathyroid hormone levels and likely not mediated through the activation of estrogen receptor alpha subtype.

Faroqui, S; Levi, M; Soleimani, M; Amlal, H

2009-01-01

105

Secluded and Proximate Illiteracy: Comparing Situations  

ERIC Educational Resources Information Center

Triplot is used to portray the three-dimensional concepts--literate, proximate illiterate and secluded illiterate. Pictographic portrayal complemented with a method proposed to calculate distance between situations enhances comparison. Illustration with Indian data explains change over time, rural-urban divide, and social gap.

Mishra, Srijit

2005-01-01

106

Current status of proximal gastric vagotomy.  

PubMed

Proximal gastric vagotomy is nearing its twentieth year in clinical use as an operation for peptic ulcer disease. No other acid-reducing operation has undergone as much scrutiny or study. At this time, the evidence of such studies and long-term follow-up strongly supports the use of proximal gastric vagotomy as the treatment of choice for chronic duodenal ulcer in patients who have failed medical therapy. Its application in treating the complications of peptic ulcer disease, which recently have come to represent an increasingly greater percentage of all operations done for peptic ulcer disease, is well-tested. However, initial series suggest that it should probably occupy a prominent role in treating some of these complications, particularly in selected patients, in the future. The operation has the well-documented ability to reduce gastric acid production, not inhibit gastric bicarbonate production, and also minimally inhibit gastric motility. The combination of these physiologic results after proximal gastric vagotomy, along with preservation of the normal antropyloroduodenal mechanism of gastrointestinal control, serve to allow patients with proximal gastric vagotomy the improved benefits of significantly fewer severe gastrointestinal side effects than are seen after other operations for peptic ulcer disease. PMID:2644897

Schirmer, B D

1989-02-01

107

Traumatic proximal tibiofibular dislocation with neurovascular injury.  

PubMed

23 years old male presented with inferolateral dislocation of proximal tibiofibular joint associated with popliteal artery and common peroneal nerve injury. The extension of the injury to involve the interosseus membrane up to the distal tibiofibular joint. The association of popliteal artery injury is not reported before to the best of our knowledge. PMID:23162155

Veerappa, Lokesh A; Gopalakrishna, Chetan

2012-09-01

108

Nonlinear Dynamics of Close Proximity Ship Towing.  

National Technical Information Service (NTIS)

The goal of this study is to investigate the nonlinear dynamics of two ships in close proximity towing. The sway and yaw dynamics of both the leading and the trailing ships were included in the formulation. Previous studies were restricted to a linear ana...

M. Korkut

2002-01-01

109

Generalized proximity potential for deformed, oriented nuclei  

SciTech Connect

The 'pocket formula' for the proximity potential is generalized for collisions of any two (equal or unequal) deformed nuclei, having any degree of (equal or unequal) orientations (from 0 deg. to 180 deg. ) in space. The method is applied to axially symmetric coplaner nuclei. The case of noncoplaner nuclei will be dealt with in a separate publication.

Gupta, Raj K.; Singh, Narinder; Manhas, Monika [Physics Department, Panjab University, Chandigarh-160014 (India)

2004-09-01

110

New approach to optical proximity correction  

Microsoft Academic Search

A hierarchical rule based optical proximity effect correction approach is presented. The approach has been driven by maskmaking and production requirements to make OPC a practical problem solution. The model based rule generation is presented, as well as benchmark tests on different state-of- the-art test chips.

Anja Rosenbusch; Andrew C. Hourd; Casper A. Juffermans; Hartmut Kirsch; Frederic P. Lalanne; Wilhelm Maurer; Carmelo Romeo; Kurt Ronse; Patrick Schiavone; Michal Simecek; Olivier Toublan; John G. Watson; Wolfram Ziegler; Rainer Zimmermann

1998-01-01

111

New approach to optical proximity correction  

NASA Astrophysics Data System (ADS)

A hierarchical rule based optical proximity effect correction approach is presented. The approach has been driven by maskmaking and production requirements to make OPC a practical problem solution. The model based rule generation is presented, as well as benchmark tests on different state-of- the-art test chips.

Rosenbusch, Anja; Hourd, Andrew C.; Juffermans, Casper A.; Kirsch, Hartmut; Lalanne, Frederic P.; Maurer, Wilhelm; Romeo, Carmelo; Ronse, Kurt; Schiavone, Patrick; Simecek, Michal; Toublan, Olivier; Watson, John G.; Ziegler, Wolfram; Zimmermann, Rainer

1998-12-01

112

Geographic Proximity and Foreign Military Intervention  

Microsoft Academic Search

Proceeding from assumptions about interests and costs, two basic questions about the relation of foreign military intervention and geographic proximity are examined: (1) whether various types of intervening countries usually send troops to distant or nearby states; (2) whether certain types of military intervention are more likely to occur near to or far from the intervener. Data on categories of

Frederic S. Pearson

1974-01-01

113

Proximity correction for electron beam lithography  

NASA Astrophysics Data System (ADS)

As the critical dimensions required in mask making and direct write by electron beam lithography become ever smaller, correction for proximity effects becomes increasingly important. Furthermore, the problem is beset by the fact that only a positive energy dose can be applied with an electron beam. We discuss techniques such as chopping and dose shifting, which have been proposed to meet the positivity requirement. An alternative approach is to treat proximity correction as an optimization problem. Two such methods, local area dose correction and optimization using a regularizer proportional to the informational entropy of the solution, are compared. A notable feature of the regularized proximity correction is the ability to correct for forward scattering by the generation of a 'firewall' set back from the edge of a feature. As the forward scattering width increases, the firewall is set back farther from the feature edge. The regularized optimization algorithm is computationally time consuming using conventional techniques. However, the algorithm lends itself to a microelectronics integrated circuit coprocessor implementation, which could perform the optimization faster than even the fastest work stations. Scaling the circuit to larger number of pixels is best approached with a hybrid serial/parallel digital architecture that would correct for proximity effects over 108 pixels in about 1 h. This time can be reduced by simply adding additional coprocessors.

Marrian, Christie R.; Chang, Steven; Peckerar, Martin C.

1996-09-01

114

Proximity correction for e-beam lithography  

NASA Astrophysics Data System (ADS)

As the critical dimensions required for masks and e-beam direct write become ever smaller, the correction of proximity effects becomes more necessary. Furthermore, the problem is beset by the fact that only a positive energy dose can be applied with the e-beam. We discuss here approaches such as chopping and dose shifting which have been proposed to meet the positivity requirement. An alternative approach is to treat proximity correction as an optimization problem. Two such methods, local area dose correction and optimization using a regularizer proportional to the informational entropy of the solution, are compared. A notable feature of the regularized proximity correction is the ability to correct for forward scattering by the generation of a 'firewall' set back from the edge of a feature. As the forward scattering width increases, the firewall is set back further from the feature edge. The regularized optimization algorithm is computationally time consuming using conventional techniques. However, the algorithm lends itself to a microelectronics integrated circuit coprocessor implementation which could perform the optimization much faster than even the fastest work stations. Scaling the circuit to larger number of pixels is best approached with a hybrid serial/parallel digital architecture which would correct for proximity effects over 108 pixels about one hour. This time can be reduced by simply adding additional coprocessors.

Marrian, Christie R.; Chang, S.; Peckerar, Martin C.

1995-12-01

115

Proximate Analysis of Dragon Fruit (Hylecereus polyhizus)  

Microsoft Academic Search

Problem statement: Dragon fruit (Hylecereus polyhizus ) is well known for the rich nutrient contents and it is commercially available worldwide for improving many health problems. Several studies show the proximity value of red pitaya frui ts but the nutrient composition of the stem has not been extensively studied. Approach: This study was carried out to measure the proximat e

Ruzainah Ali Jaafar; Ahmad Ridhwan; R. Vasudevan

2009-01-01

116

Proximal calciphylaxis treated with calcimimetic 'cinacalcet  

Microsoft Academic Search

Calciphylaxisisarareconditionaffectingpatientssuffering from end-stage renal failure, characterised by cutaneous ischaemia and necrosis. The management of calciphylaxis is challenging owing to the lack of optimal medical therapy, although parathyroidectomy has shown some benefit. We present a case of severe proximal calciphylaxis treated with a small dose of the calcimimetic 'Cinacalcet'.

Ismail A. Mohammed; Vashisht Sekar; Abdullah J. Bubtana; Sandip Mitra; Alastair J. Hutchison

117

Proximal superior mesenteric arterial and venous injuries  

Microsoft Academic Search

In a review of more than 1000 patients with operatively managed abdominal trauma, eight patients with injuries to the proximal parts of the superior mesenteric artery or vein were identified: three with either a superior mesenteric artery or vein injury and two with combined superior mesenteric vessel injuries. All patients were in shock on arrival, and had associated abdominal injuries.

Ari K. Leppäniemi; Hannu O. Savolainen; Jarmo A. Salo; Pertti T. Aarnio

1995-01-01

118

Proximity economics and environment: assessment and prospects  

Microsoft Academic Search

The use of the theoretical tools provided by proximity economics to address environmental questions, and the emergence of analyses revitalising the role of the spatial dimension in environmental problems, date from the late 1990s. This paper first aims to provide a review of the research conducted in this field and second to suggest some future research directions concerning the respective

André Torre; Bertrand Zuindeau

2009-01-01

119

Scanning proximity probes for nanoscience and nanofabrication  

Microsoft Academic Search

The AFM-technology has undergone tremendous development during the past decade. This review is devoted to the realization of piezoresistive sensors used in scanning probe microscopy at University of Kassel. It is expected that in the near future major technological breakthroughs in scanning proximal probe nanotools will allow for key scientific impact on analysis and synthesis of nanostructures. All the piezoresistive

Ivo W. Rangelow

2006-01-01

120

Prosthetic replacement for proximal humeral fractures.  

PubMed

The ideal management of complex proximal humeral fractures continues to be debatable. Evolution of proximal humeral fracture management, during the past decade, led to the implementation of many innovations in surgical treatment. Even though the pendulum of treatment seems to swing towards new trends such as locked plating, hemiarthroplasty remains a valid and reliable option that serves the patient's needs well. Hemiarthroplasty is indicated for complex proximal humeral fractures in elderly patients with poor bone stock and when internal fixation is difficult or unreliable. Hemiarthroplasty provides a better result when it is performed early post-injury. Stem height, retroversion and tuberosity positioning are technical aspects of utmost importance. Additionally reverse total shoulder arthroplasty is an alternative new modality that can be used as a primary solution in selected patients with proximal humeral fracture treatment. Failed hemiarthroplasty and fracture sequelae can be successfully managed with reverse total shoulder arthroplasty. Individual decision-making and tailored treatment that takes into consideration the personality of the fracture and the patient's characteristics should be used. PMID:19036360

Kontakis, George; Tosounidis, Theodoros; Galanakis, Ioannis; Megas, Panagiotis

2008-11-25

121

Empathy: Its ultimate and proximate bases  

Microsoft Academic Search

Short abstract The empathy literature is characterized by debate regarding the nature of the phenomenon. We propose a unified theory of empathy, divided into ultimate and proximate levels, grounded in the emotional link between individuals. On an ultimate level, emotional linkage supports group alarm, vicariousness of emotions, mother-infant responsiveness, and the modeling of competitors and predators; these exist across species

Stephanie D. Preston

2002-01-01

122

Effect of Epinephrine on ?-Methyl-D-Glucopyranoside Uptake in Renal Proximal Tubule Cells  

Microsoft Academic Search

Effect of epinephrine on ?-methyl-D-glucopyranoside uptake in renal proximal tubule cells. Epinephrine has known to be a very important factor in the regulation of renal sodium excretion. However, the effect of epinephrine on Na+\\/glucose cotransporter was not fully elucidated. Thus, we examined effect of epinephrine on ?-methyl-D-glucopyranoside (?-MG) uptake and its related signal pathways in the primary cultured rabbit renal

Eun Kim; Yun Lee; Jang Lee; Ho Han

2004-01-01

123

Phosphate, calcium and magnesium fluxes into the lumen of the rat proximal convoluted tubule  

Microsoft Academic Search

In order to study fluxes of phosphate (Pi), Ca and Mg into the rat proximal tubule, a modification of the split-droplet microinjection technique was used. Injected fluids were isotonic solutions containing no Pi, Ca or Mg. The initial NaCl concentration of the injectates was either (a) 115 mM\\/l (which resulted in net fluid entry into the lumen), (b) 125 mM\\/l

D. G. Shirley; P. Poujeol; C. Grimellec

1976-01-01

124

Proximal Tubular Hypertrophy and Enlarged Glomerular and Proximal Tubular Urinary Space in Obese Subjects with Proteinuria  

PubMed Central

Background Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. Objective To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. Methods Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman’s space and the nuclei number per tubular profile were estimated. Results Creatinine clearance was higher in the obese than in the lean group (P=0.03). Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001), a 94% higher Bowman’s space volume (P=0.003), a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02) and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01). The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. Conclusions Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity-related renal disease.

Benchetrit, Sydney; Milo, Gai; Herman-Edelstein, Michal; Zingerman, Boris; Lev, Netta; Gafter, Uzi; Chagnac, Avry

2013-01-01

125

Chloride transport across the basolateral cell membrane of the Necturus proximal tubule: Dependence on bicarbonate and sodium  

Microsoft Academic Search

Summary The transport of chloride across theNecturus proximal tubule cell was studied in the doubly-perfused kidney using conventional, chloride-sensitive and pH-sensitive microelectrodes. Lowering chloride activity in the basolateral solution results in a reduction in intracellular Cl- activity (aCli). This reduction inaCli is inhibited by removing either HCO3- or Na+ from the perfusion solution, indicating that both HCO3- and Na+ are

W. B. Guggino; E. L. Boulpaep; G. Giebisch

1983-01-01

126

Changes in Sodium or Glucose Filtration Rate Modulate Expression of Glucose Transporters in Renal Proximal Tubular Cells of Rat  

Microsoft Academic Search

.   Renal glucose reabsorption is mediated by luminal sodium-glucose cotransporters (SGLTs) and basolateral facilitative glucose\\u000a transporters (GLUTs). The modulators of these transporters are not known, and their substrates glucose and Na+ are potential candidates. In this study we examined the role of glucose and Na+ filtration rate on gene expression of glucose transporters in renal proximal tubule. SGLT1, SGLT2, GLUT1

S. Vestri; M. M. Okamoto; H. S. de Freitas; R. Aparecida dos Santos; M. T. Nunes; M. Morimatsu; J. C. Heimann; U. F. Machado

2001-01-01

127

Proximal-type epithelioid sarcoma - Case report*  

PubMed Central

Epithelioid sarcoma, first described by Enzinger in 1970, is a rare soft-tissue sarcoma typically presenting as a subcutaneous or deep dermal mass in distal portions of the extremities of adolescents and young adults. In 1997, Guillou et al. described a different type of epithelioid sarcoma, called proximal-type epithelioid sarcoma, which is found mostly in the pelvic and perineal regions and genital tracts of young to middle-aged adults. It is characterized by a proliferation of epithelioid-like cells with rhabdoid features and the absence of a granuloma-like pattern. In this paper we present a case of proximal-type epithelioid sarcoma with an aggressive clinical course, including distant metastasis and death nine months after diagnosis.

dos Santos, Luciana Mendes; Nogueira, Lisiane; Matsuo, Christiane Yuri; Talhari, Carolina; Santos, Monica

2013-01-01

128

Clinical Impact of Proximal Autosomal Imbalances  

PubMed Central

Centromere-near gain of copy number can be induced by intra- or inter-chromosomal rearrangements or by the presence of a small supernumerary marker chromosome (sSMC). Interestingly, partial trisomy to hexasomy of euchromatic material may be present in clinically healthy or affected individuals, depending on origin and size of chromosomal material involved. Here we report the known minimal sizes of all centromere-near, i.e., proximal auto-somal regions in humans, which are tolerated; over 100 Mb of coding DNA are comprised in these regions. Additionally, we have summarized the typical symptoms for nine proximal autosomal regions including genes obviously sensitive to copy numbers. Overall, studying the carriers of specific chromosomal imbalances using genomics-based medicine, combined with single cell analysis can provide the genotype-phenotype correlations and can also give hints where copy-number-sensitive genes are located in the human genome.

Hamid, AB; Weise, A; Voigt, M; Bucksch, M; Kosyakova, N; Liehr, T; Klein, E

2012-01-01

129

Superconducting Proximity Effect in Thin Semiconducting Films  

Microsoft Academic Search

We report results using a novel 3 terminal device to study the influence of the superconducting proximity effect on the sheet resistance of the N-layer, Rs, as well as the junction conductance across the N-S boundary, Gc. When the N-layer is a degenerate semiconductor the changes in these quantities are large. In samples with large Gc, we find that the

Michael Vissers; Kevin Inderhees; Tim McArdle; Stephanie Law; Paul Goldbart; Laura Greene; Jim Eckstein

2009-01-01

130

Simulated temperature distribution of the proximal forearm  

Microsoft Academic Search

Temperature changes in the resting proximal human forearm have been studied non-invasively, using computer simulation. A procedure for spatial model generation, based on digitized slice data, has been applied. A mathematical model and a 3-D computer simulation program have been implemented. Heat transfer in the non-homogenous tissue was modeled with a well known bio-heat equation. The heat production by tissue

Roman Trobec; Matjaž Depolli

2011-01-01

131

Proximity effects in superconductor-ferromagnet heterostructures  

Microsoft Academic Search

The proximity effect at superconductor-ferromagnet interfaces produces damped oscillatory behavior of the Cooper pair wave function within the ferromagnetic medium. This is analogous to the inhomogeneous superconductivity, predicted long ago by Fulde and Ferrell (P. Fulde and R. A. Ferrell, 1964, ``Superconductivity in a strong spin-exchange field,'' Phys. Rev. 135, A550-A563), and by Larkin and Ovchinnikov (A. I. Larkin and

A. I. Buzdin

2005-01-01

132

Examination of Derecho Environments Using Proximity Soundings  

Microsoft Academic Search

Observed upper air soundings that occurred within 2 h and 167 km of derechos were collected and analyzed to document atmospheric stability and wind shear conditions associated with long-lived convective windstorms. Sixty-seven derechos, accompanied by 113 proximity soundings, were identified during the years 1983-93. Owing to the large variability of the synoptic-scale environments associated with derechos, each derecho was further

Jeffry S. Evans; Charles A. Doswell III

2001-01-01

133

Proximal myopathy: diagnostic approach and initial management.  

PubMed

Proximal myopathy presents as symmetrical weakness of proximal upper and/or lower limbs. There is a broad range of underlying causes including drugs, alcohol, thyroid disease, osteomalacia, idiopathic inflammatory myopathies (IIM), hereditary myopathies, malignancy, infections and sarcoidosis. Clinical assessment should aim to distinguish proximal myopathy from other conditions that can present similarly, identify patients who need prompt attention, like those with cardiac, respiratory or pharyngeal muscle involvement, and determine underlying cause of myopathy. Initial evaluation should include simple tests, like creatine kinase, thyroid function and (25)OH vitamin D levels, but further evaluation including neurophysiological studies, muscle imaging and muscle biopsy should be considered for patients in whom no toxic, metabolic or endocrine cause is found, and in those with clinical features suggestive of inflammatory or hereditary myopathy. Additionally, screening for malignancy and testing for anti-Jo1 antibody is indicated for selected patients with IIM. Management depends on underlying cause, and includes measures, such as removal of offending agent, correction of endocrine or metabolic problem, corticosteroids and immunosuppressive therapy for IIM, and physical therapy, rehabilitation and genetic counselling for muscular dystrophies. PMID:23596213

Suresh, Ernest; Wimalaratna, Sunil

2013-04-17

134

Proximity effects in topological insulator heterostructures  

NASA Astrophysics Data System (ADS)

Topological insulators (TIs) are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to Tl-based heterostructures, in which conventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insulator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topological helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath. These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI-based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications.

Li, Xiao-Guang; Zhang, Gu-Feng; Wu, Guang-Fen; Chen, Hua; Dimitrie, Culcer; Zhang, Zhen-Yu

2013-09-01

135

Topological Proximity Effects in Graphene Nanoribbon Heterostructures  

NASA Astrophysics Data System (ADS)

Topological insulators (TI) are bulk insulators that possess robust chiral conducting states along their interfaces with normal insulators. A tremendous research effort has recently been devoted to TI-based heterostructures, in which conventional proximity effects give rise to many exotic physical phenomena. Here we establish the potential existence of ``topological proximity effect'' at the interface of a topological graphene nanoribbon (GNR) and a normal GNR. Specifically, we show that the location of the topological edge states exhibits versatile tunability as a function of the interface orientation, as well as the strengths of the interface coupling and spin-orbit coupling in the normal GNR. For zigzag and bearded GNRs, the topological edge state can be tuned to be either at the interface or outer edge of the normal ribbon. For armchair GNR, the potential location of the topological edge state can be further enriched to be at the edge of or within the normal ribbon, at the interface, or diving into the topological GNR. We also discuss potential experimental realization of the predicted topological proximity effects, which may pave the way for integrating the salient functionality of TI and graphene in future device applications.

Zhang, Gufeng; Li, Xiaoguang; Wu, Guangfen; Wang, Jie; Culcer, Dimitrie; Kaxiras, Efthimios; Zhang, Zhenyu

2013-03-01

136

Analytical parametrization of fusion barriers using proximity potentials  

SciTech Connect

Using the three versions of proximity potentials, namely proximity 1977, proximity 1988, and proximity 2000, we present a pocket formula for fusion barrier heights and positions. This was achieved by analyzing as many as 400 reactions with mass between 15 and 296. Our parametrized formula can reproduced the exact barrier heights and positions within an accuracy of +-1%. A comparison with the experimental data is also in good agreement.

Dutt, Ishwar; Puri, Rajeev K. [Department of Physics, Panjab University, Chandigarh 160014 (India)

2010-06-15

137

Altered renal proximal tubular endocytosis and histology in mice lacking myosin-VI.  

PubMed

Myosin VI (Myo6) is an actin-based molecular motor involved in clathrin-mediated endocytosis that is highly expressed in the renal proximal tubule brush border. We investigated the renal physiological consequences of loss of Myo6 function by performing renal clearance and physiological measurements on Myo6 functional null Snell's waltzer (sv/sv) and control heterozygous (+/sv) mice. Sv/sv mice showed reduced body weight and elevated blood pressure compared with controls; no differences were observed for glomerular flow rate, urine volume, blood acid-base parameters, and plasma concentrations and urinary excretions of Na(+) and K(+). To assess the integrity of endocytosis-mediated protein absorption by the kidney, urinary albumin excretion was measured, and the proximal tubular uptake of intravenously injected endocytic marker horseradish peroxidase (HRP) was examined. Albumin excretion was increased nearly 4-fold in sv/sv mice relative to controls. Conversely, HRP uptake was reduced and delayed in proximal tubule cells of the sv/sv kidney observed by electron microscopy at 5 and 30 min after injection. Consistent with impaired endocytosis, we also observed defects indicating alterations along the endocytic pathway in sv/sv proximal tubule cells: (1) decreased membrane association of the clathrin adaptor subunit, adaptin beta, and Disabled-2 (Dab2) after sedimentation of renal homogenates and (2) reduced apical vacuole number. In addition, proximal tubular dilation and fibrosis, likely secondary effects of the loss of Myo6, were observed in sv/sv kidneys. These results indicate that Myo6 plays a key role in endocytosis-mediated protein absorption in the mouse kidney proximal tubule. PMID:20175219

Gotoh, Nanami; Yan, Qingshang; Du, Zhaopeng; Biemesderfer, Daniel; Kashgarian, Michael; Mooseker, Mark S; Wang, Tong

2010-03-01

138

Proximity and Interactive Learning in University-Firm Relationships  

ERIC Educational Resources Information Center

This paper addresses the question of whether proximity is always necessary for interactive learning, as proposed by recent European innovation theory. Recent research has provided a refined conceptualization of proximity, but there is little empirically-based knowledge about the actual role that proximity plays in relationships intended to foster…

Thune, Taran

2009-01-01

139

The Geographical and Institutional Proximity of Scientific Collaboration Networks  

Microsoft Academic Search

The geography of innovation has established itself as a central subject in economic geography. Geographical proximity to firms and organizations like universities is supposed to have a positive effect on a firms’ innovative performance. One of the reasons causing these positive agglomeration effects is the fact that collaboration is eased by geographical proximity. Although the role of proximity for collaboration

Frank Van Oort; Roderik Ponds; Koen Frenken

2006-01-01

140

Distal and variably proximal causes: Education, obesity, and health  

Microsoft Academic Search

Medical sociologists hold that social conditions generate disparities across a host of health conditions through exposure to a variety of more proximate risk factors. Though distal and proximal causes jointly influence disease, the nature of risk accumulation may differ appreciably by the link of a proximal cause to the outcome in question. This paper employs a representative sample of over

Markus H. Schafer; Kenneth F. Ferraro

2011-01-01

141

Early effects of uranyl nitrate on respiration and K sup + transport in rabbit proximal tubule  

SciTech Connect

The mechanisms by which uranyl nitrate (UN) is toxic to the proximal tubule are incompletely understood. To define these further we studied potassium (K+) transport and oxygen consumption (QO2) in rabbit proximal tubule suspensions in vitro immediately after exposure to UN using extracellular O2- and K+-sensitive electrodes. UN caused a cumulative dose-dependent inhibition of proximal tubule QO2, with a threshold concentration of 5 x 10(-5) M. Kinetic analysis suggested two patterns of cell injury: a higher affinity inhibition of QO2 with a Ki of 5 x 10(-4) M, and a lower affinity inhibition of QO2 with a Ki of 10 mM. QO2 was studied in detail in the presence of these Ki concentrations of UN to define the initial cellular events. The results indicated that different cellular processes displayed different sensitivities to UN. At submillimolar concentrations UN caused progressive selective inhibition of ouabain-insensitive QO2 (15% inhibition at 2 minutes). Ouabain-sensitive QO2 and nystatin-stimulated QO2 were not affected, suggesting that Na+,K+-ATPase activity and its coupling to mitochondrial ATP synthesis were intact. Direct measurement of proximal tubule net K+ flux confirmed that Na+,K+-ATPase activity was unchanged. Similarly, UN did not inhibit basal (state 4) or ADP-stimulated (state 3) mitochondrial QO2 in digitonin-permeabilized tubules, confirming that the mitochondria were intact. In contrast, higher concentrations of UN (greater than or equal to 1 mM) caused rapid inhibition of QO2 and net K+ efflux, due to inhibition of Na+,K+-ATPase activity and mitochondrial injury.

Brady, H.R.; Kone, B.C.; Brenner, R.M.; Gullans, S.R. (Brigham and Women's Hospital, Boston, MA (USA))

1989-07-01

142

Management of proximal interphalangeal joint injuries  

PubMed Central

Injuries to the proximal interphalangeal joint are common but frequently missed. They are often overtreated by prolonged immobilization, resulting in stiffness, which may be permanent. The purpose of the present article is to briefly review the relevant anatomy and biomechanics, present an approach to physical examination and diagnosis, and propose a practical clinical classification. The treatment of the most severe injury – the intra-articular fracture dislocation – is controversial. The various treatment options are discussed, based on personal experience and a review of the literature. A list of relevant references is presented.

Freiberg, Arnis

2007-01-01

143

Giant cell tumour of the proximal radius.  

PubMed

A 52-year-old Indian woman presented with a progressively increasing swelling and pain in the right elbow for the past eight months, which was not associated with trauma or constitutional symptoms. The patient was diagnosed to have Campanacci grade III giant cell tumour of the proximal radius, and was treated with above elbow amputation. The patient has not shown any recurrence after five years of follow-up. The case was reported because of its rarity and the unusual site of occurrence of the tumour. PMID:19960152

Singh, A P; Mahajan, S; Singh, A P

2009-11-01

144

Transport magnetic proximity effects in platinum.  

PubMed

Platinum (Pt) metal, being nonmagnetic and with a strong spin-orbit coupling interaction, has been central in detecting the pure spin current and establishing most of the recent spin-based phenomena. Magnetotransport measurements, both electrical and thermal, conclusively show strong ferromagnetic characteristics in thin Pt films on the ferromagnetic insulator due to the magnetic proximity effects. The pure spin current phenomena measured by Pt, including the inverse spin Hall and the spin Seebeck effects, are thus contaminated and not exclusively established. PMID:23005323

Huang, S Y; Fan, X; Qu, D; Chen, Y P; Wang, W G; Wu, J; Chen, T Y; Xiao, J Q; Chien, C L

2012-09-07

145

Ontogeny of rabbit proximal tubule urea permeability.  

PubMed

Urea transport in the proximal tubule is passive and is dependent on the epithelial permeability. The present study examined the maturation of urea permeability (P(urea)) in in vitro perfused proximal convoluted tubules (PCT) and basolateral membrane vesicles (BLMV) from rabbit renal cortex. Urea transport was lower in neonatal than adult PCT at both 37 and 25 degrees C. The PCT P(urea) was also lower in the neonates than the adults (37 degrees C: 45.4 +/- 10.8 vs. 88.5 +/- 15.2 x 10(-6) cm/s, P < 0.05; 25 degrees C: 28.5 +/- 6.9 vs. 55.3 +/- 10.4 x 10(-6) cm/s; P < 0.05). The activation energy for PCT P(urea) was not different between the neonatal and adult groups. BLMV P(urea) was determined by measuring vesicle shrinkage, due to efflux of urea, using a stop-flow instrument. Neonatal BLMV P(urea) was not different from adult BLMV P(urea) at 37 degrees C [1.14 +/- 0.05 x 10(-6) vs. 1.25 +/- 0.05 x 10(-6) cm/s; P = not significant (NS)] or 25 degrees C (0.94 +/- 0.06 vs. 1.05 +/- 0.10 x 10(-6) cm/s; P = NS). There was no effect of 250 microM phloretin, an inhibitor of the urea transporter, on P(urea) in either adult or neonatal BLMV. The activation energy for urea diffusion was also identical in the neonatal and adult BLMV. These findings in the BLMV are in contrast to the brush-border membrane vesicles (BBMV) where we have previously demonstrated that urea transport is lower in the neonate than the adult. Urea transport is lower in the neonatal proximal tubule than the adult. This is due to a lower rate of apical membrane urea transport, whereas basolateral urea transport is the same in neonates and adults. The lower P(urea) in neonatal proximal tubules may play a role in overall urea excretion and in developing and maintaining a high medullary urea concentration and thus in the ability to concentrate the urine during renal maturation. PMID:11353675

Quigley, R; Lisec, A; Baum, M

2001-06-01

146

Cephalomedullary nailing for proximal femoral fractures.  

PubMed

From May 1999 to April 2002, we treated 14 patients with subtrochanteric femoral fractures and seven patients with ipsilateral fractures of the femoral neck and shaft using a second-generation cephalomedullary interlocked nail. Patients mean age was 36 (20-60) years, and 19 fractures were caused by high-energy trauma. Four patients had associated injuries. The average follow-up was 23 (16-30) months. Per-operatively, we had problems in locating the entry portal in four patients, and one nail was driven through the inter-condylar notch. All fractures except two united. One patient had non-union of the femoral neck and one of both neck and shaft. One patient united with shortening of more than 1.5 cm and varus angulation at the fracture site. Two patients had loosening and backing out of the proximal screw. The second-generation cephalomedullary nail is a suitable treatment option for proximal femoral fractures, but it requires a high degree of accuracy and technical expertise. PMID:15647914

Kakkar, Rahul; Kumar, S; Singh, A K

2005-01-13

147

Hfq proximity and orientation controls RNA annealing  

PubMed Central

Regulation of bacterial gene networks by small non-coding RNAs (sRNAs) requires base pairing with messenger RNA (mRNA) targets, which is facilitated by Hfq protein. Hfq is recruited to sRNAs and mRNAs through U-rich- and A-rich-binding sites, respectively, but their distance from the sRNA–mRNA complementary region varies widely among different genes. To determine whether distance and binding orientation affect Hfq’s chaperone function, we engineered ‘toy’ RNAs containing strong Hfq-binding sites at defined distances from the complementary target site. We show that RNA annealing is fastest when the distal face of Hfq binds an A-rich sequence immediately 3? of the target. This recruitment advantage is lost when Hfq binds >20?nt away from the target, but is partially restored by secondary structure that shortens this distance. Although recruitment through Hfq’s distal face accelerates RNA annealing, tight binding of six Us to Hfq’s proximal face inhibits annealing. Finally, we show that ectopic A-rich motifs dramatically accelerate base pairing between DsrA sRNA and a minimal rpoS mRNA in the presence of Hfq, demonstrating that proximity and orientation predict the activity of Hfq on long RNAs.

Panja, Subrata; Woodson, Sarah A.

2012-01-01

148

Superconducting Proximity Effect in Thin Semiconducting Films  

NASA Astrophysics Data System (ADS)

We report results using a novel 3 terminal device structure that provides two independent resistance measurements that we use to examine the influence of the superconducting proximity effect on both the transport properties of the thin film N layer by quantifying its sheet resistance, Rs, as well as independently measuring the junction conductance across the N-S boundary, Gc. When the N layer is a degenerate semiconductor the changes in these quantities are large. Gc increases much more than the factor of 2 that Andreev Reflection or BTK theory predicts, and both Gc and Rs exhibit reentrance as temperature decreases. We interpret these effects as being due to a transition between a phase fluctuating and phase stiff proximity effect in the N layer. This manifests itself by moving the N-S electrical boundary into the semiconductor, increasing Gc, while simultaneously removing volume available to normal transport forcing the measured Rs to increase. This work was supported by the DOE BES at the F. Seitz Materials Research Laboratory at the University of Illinois, Urbana.

Vissers, Michael; Flexner, Soren; Welander, Paul; Inderhees, Kevin; McArdle, Tim; Eckstein, Jim

2008-03-01

149

Posttraumatic proximal interphalangeal joint flexion contractures.  

PubMed

Normal motion of the proximal interphalangeal joint requires bony support, intact articular surfaces, unimpeded tendon gliding, and uncompromised integrity of the collateral ligaments and volar plate. Deficiency in any one of these structural requirements can lead to a loss of finger joint motion and decreased hand function. Once finger extension is lost, options include nonsurgical or surgical treatment. Nonsurgical treatment such as splinting or serial casting should be tried before attempting surgical intervention. When severe flexion deformity exists or the vascular status of the finger has been compromised, arthrodesis or amputation should be undertaken instead of procedures to regain motion. Surgical options for regaining motion include external fixators and open surgical release. Although they can lead to improved extension at the proximal interphalangeal joint, external fixators carry a risk of reduced finger flexion and pin site infection. Most clinical series of patients who have undergone surgical release document improvement in flexion contracture between 25 degrees to 30 degrees and a shift of the flexion/extension arc into a more functional range. Close follow-up after surgery is warranted, with frequent physical therapy and splinting. PMID:16959890

Hogan, Christopher J; Nunley, James A

2006-09-01

150

Proximate determinants of fertility in peninsular Malaysia.  

PubMed

The continuing decline in fertility despite a contraction in contraceptive use in Peninsular Malaysia since the mid-1980s has triggered considerable interest in the reasons behind this phenomenon, such as increase in abortion, sterility, and out-of-wedlock pregnancy. Fertility decline has been attributed to rapid socioeconomic development, which can only influence fertility through the intermediate variables. Application of vital statistics, population census, and survey data of Peninsular Malaysia on Bongaarts's model vindicates that marriage postponement and contraceptive use are the 2 most important proximate determinants of fertility, but the effects are not uniform across the ethnic groups. For instance, the predicted total fertility rate for Chinese and Malays are 2.9 and 1.6, respectively, compared with the observed level of 3.0 and 1.9. Postpartum infecundability and abortion also play a part in explaining ethnic fertility differentials. The fertility inhibiting effects of these proximate determinants have significant implications on reproductive health and future population growth. PMID:21490114

Tey, Nai Peng; Ng, Sor Tho; Yew, Siew Yong

2011-04-13

151

Multiplication-stimulating activity-induced alkalinization of canine renal proximal tubular cells  

SciTech Connect

The actions of a variety of polypeptide growth factors on isolated cells are thought to be initiated by stimulation of Na/sup +/-H/sup +/ exchange across the plasma membranes of the cells resulting in intracellular alkalinization. To determine whether insulin-like growth factors (IGFs) exert actions through such a mechanism, the authors incubated suspensions of canine renal proximal tubular segments with insulin or IGF I or with multiplication-stimulating activity (MSA)/IGF II. Changes in intracellular pH were detected by measurements of the distribution of (/sup 14/C)5,5-dimethoxazolidine-2,4-dione. Incubation of segments with 10/sup +9/ M MSA under conditions such that extracellular (Na/sup +/)> intracellular (Na/sup +/) effected intracellular alkalinization detectable within 1-2 min. Alkalinization was not observed under conditions where this gradient was not present. Alkalinization was not prevented by inclusion of 1mM 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid or 1 mM ouabain in incubations, but was inhibited by amiloride. Incubation of proximal tubular segments with as little as 10/sup +11/ M MSA effected intracellular alkalinization. Incubation with as much as 10/sup -6/ M insulin or IGF I did not. Our findings are consistent with an action of MSA/IGF II to stimulate Na/sup +/-H/sup +/ exchange across the plasma membrane of the renal proximal tubular cell. It is possible that the stimulation represents a mechanism by which actions of IGF II are initiated in growth factor-sensitive cells.

Mellas, J.; Gavin, J.R. III; Hammerman, M.R.

1986-11-05

152

Proximity effect in iridium-gold bilayers  

NASA Astrophysics Data System (ADS)

We have studied the proximity effect in bilayers of thin films of iridium covered by gold. By varying the thicknesses of the iridium and gold layers, we achieved critical temperatures as low as 33 mK. The critical temperature of the bilayers is lower than predicted by the theory of the Gennes-Werthamer (1964), but adding a free parameter to the theory allows good agreement. The transitions of the bilayers typically had widths of a few mK, with the narrowest reaching 0.2 mK, and were always steeper than those of pure iridium films evaporated simultaneously. Such bilayers can be used as superconducting phase transition thermometers in cryogenic particle detectors.

Nagel, U.; Nowak, A.; Gebauer, H.-J.; Colling, P.; Cooper, S.; Dummer, D.; Ferger, P.; Frank, M.; Igalson, J.; Nucciotti, A.

1994-10-01

153

Proximal-distal axis formation in the Drosophila leg  

Microsoft Academic Search

Limb development requires the formation of a proximal-distal axis perpendicular to the main anterior-posterior and dorsal-ventral body axes. The secreted signalling proteins Decapentaplegic and Wingless act in a concentration-dependent manner to organize the proximal-distal axis. Discrete domains of proximal-distal gene expression are defined by different thresholds of Decapentaplegic and Wingless activities. Subsequent modulation of the relative sizes of these domains

Thomas Lecuit; Stephen M. Cohen

1997-01-01

154

Proximity-dependent and proximity-independent trans-splicing in mammalian cells.  

PubMed

Most human pre-mRNAs are cis-spliced, removing introns and joining flanking exons of the same RNA molecule. However, splicing of exons present on separate pre-mRNA molecules can also occur. This trans-splicing reaction can be exploited by pre-trans-splicing molecules (PTMs), which are incapable of cis-splicing. PTM-mediated trans-splicing has been utilized to repair mutant RNAs as a novel approach to gene therapy. Herein we explore how the site of PTM expression influences trans-splicing activity. We stably inserted a PTM expression cassette into the genome of HEK293 cells, generating clonal lines with single, unique insertion sites. We analyzed trans-splicing to the gene where the PTM was integrated, as well as genes neighboring these loci. We observed some pre-mRNAs only serve as substrates for trans-splicing when they are expressed in immediate proximity to the PTM expression site. The need for PTMs to be in close proximity with pre-mRNAs to trans-splice with them is consistent with the observation that pre-mRNA cis-splicing occurs cotranscriptionally. Interestingly, we identified several cellular pre-mRNAs in one localized area that serve as trans-splicing substrates irrespective of the PTM expression site. Thus, we find multiple cellular pre-mRNAs require PTM expression in close proximity to trans-splice while others do not. PMID:18441053

Viles, Kristi D; Sullenger, Bruce A

2008-04-25

155

Proximity-dependent and proximity-independent trans-splicing in mammalian cells  

PubMed Central

Most human pre-mRNAs are cis-spliced, removing introns and joining flanking exons of the same RNA molecule. However, splicing of exons present on separate pre-mRNA molecules can also occur. This trans-splicing reaction can be exploited by pre-trans-splicing molecules (PTMs), which are incapable of cis-splicing. PTM-mediated trans-splicing has been utilized to repair mutant RNAs as a novel approach to gene therapy. Herein we explore how the site of PTM expression influences trans-splicing activity. We stably inserted a PTM expression cassette into the genome of HEK293 cells, generating clonal lines with single, unique insertion sites. We analyzed trans-splicing to the gene where the PTM was integrated, as well as genes neighboring these loci. We observed some pre-mRNAs only serve as substrates for trans-splicing when they are expressed in immediate proximity to the PTM expression site. The need for PTMs to be in close proximity with pre-mRNAs to trans-splice with them is consistent with the observation that pre-mRNA cis-splicing occurs cotranscriptionally. Interestingly, we identified several cellular pre-mRNAs in one localized area that serve as trans-splicing substrates irrespective of the PTM expression site. Thus, we find multiple cellular pre-mRNAs require PTM expression in close proximity to trans-splice while others do not.

Viles, Kristi D.; Sullenger, Bruce A.

2008-01-01

156

Axial heterogeneity of sodium-bicarbonate cotransport in proximal straight tubule of rabbit kidney  

Microsoft Academic Search

Intracellular microelectrodes were used to investigate rheogenic Na+(HCO3-)n cotransport in different segments of isolated proximal straight tubule (PST) of rabbit kidney. In the first portion (S2 segment) the peritubular cell membrane potentialVb averaged -46.0, SE±1.3 mV (n=20), while in the terminal portion (S3 segment) it averaged -68.3, SE±2.5 mV (n=10). This difference may reflect different modes of anion permeation across

Y. Kondo; E. Friimter

1987-01-01

157

Long proximal femoral nail in ipsilateral fractures proximal femur and shaft of femur  

PubMed Central

Background: Ipsilateral fractures of the proximal femur and femoral shaft are extremely uncommon injuries which occur in young adults who sustain a high energy trauma. A variety of management modalities have been tried to treat this complex fracture pattern ranging from conservative approach to recently introduced reconstruction nails. All these approaches have their own difficulties. We studied the outcome of long proximal femoral nail (LPFN) in the management of concomitant ipsilateral fracture of the proximal femur and femoral shaft. Materials and Methods: We analysed the prospective data of 36 consecutive patients who had sustained a high energy trauma (30 closed fractures and 6 open shaft fractures) who had concomitant ipsilateral fractures of the femoral shaft associated with proximal femur fractures treated with LPFN between December 2005 and December 2011. The mean age was 39 years (range 28-64 years). Twenty nine males and seven females were enrolled for this study. Results: The patients were followed up at three, six, twelve, and eighteen months. The mean healing time for the neck fractures was 4.8 months and for the shaft fractures was 6.2 months. The greater trochanter was splintered and widened in two cases which eventually consolidated. Two patients had superficial infection, two patients had lateral migration of the screws with coxa vara which was due to severe osteoporosis detected during the followup. We had two cases of nonunion of shaft fracture and one case of nonunion of neck fracture. Two cases of avascular necrosis of femoral head were detected after 2 years of followup. No cases of implant failure were noted. Limb shortening of less than 2 cms was noted in four of our patients. The functional assessment system of Friedman and Wyman was used for evaluating the results. In our series 59.9% (n = 23) were rated as good, 30.6% (n = 11) as fair, and 5.5% (n = 2) as poor. Conclusion: Long PFN is a reliable option for concomitant ipsilateral diaphyseal and proximal femur fractures.

Gadegone, WM; Lokhande, Vijayanand; Salphale, Yogesh; Ramteke, Alankar

2013-01-01

158

Differences in cardiac microcirculatory wave patterns between the proximal left mainstem and proximal right coronary artery  

PubMed Central

Despite having almost identical origins and similar perfusion pressures, the flow-velocity waveforms in the left and right coronary arteries are strikingly different. We hypothesized that pressure differences originating from the distal (microcirculatory) bed would account for the differences in the flow-velocity waveform. We used wave intensity analysis to separate and quantify proximal- and distal-originating pressures to study the differences in velocity waveforms. In 20 subjects with unobstructed coronary arteries, sensor-tipped intra-arterial wires were used to measure simultaneous pressure and Doppler velocity in the proximal left main stem (LMS) and proximal right coronary artery (RCA). Proximal- and distal-originating waves were separated using wave intensity analysis, and differences in waves were examined in relation to structural and anatomic differences between the two arteries. Diastolic flow velocity was lower in the RCA than in the LMS (35.1 ± 21.4 vs. 56.4 ± 32.5 cm/s, P < 0.002), and, consequently, the diastolic-to-systolic ratio of peak flow velocity in the RCA was significantly less than in the LMS (1.00 ± 0.32 vs. 1.79 ± 0.48, P < 0.001). This was due to a lower distal-originating suction wave (8.2 ± 6.6 × 103 vs. 16.0 ± 12.2 × 103 W·m?2·s?1, P < 0.01). The suction wave in the LMS correlated positively with left ventricular pressure (r = 0.6, P < 0.01) and in the RCA with estimated right ventricular systolic pressure (r = 0.7, P = 0.05) but not with the respective diameter in these arteries. In contrast to the LMS, where coronary flow velocity was predominantly diastolic, in the proximal RCA coronary flow velocity was similar in systole and diastole. This difference was due to a smaller distal-originating suction wave in the RCA, which can be explained by differences in elastance and pressure generated between right and left ventricles.

Hadjiloizou, Nearchos; Davies, Justin E.; Malik, Iqbal S.; Aguado-Sierra, Jazmin; Willson, Keith; Foale, Rodney A.; Parker, Kim H.; Hughes, Alun D.; Francis, Darrel P.; Mayet, Jamil

2008-01-01

159

High Resolution Standard Proximity Sensor (HRSPS)  

NASA Astrophysics Data System (ADS)

This paper presents the final results of the performances of the High Resolution Standard Proximity Sensor developed under a GSTP contract for ESA/ESTEC. The HRSPS is a general purpose displacement measuring system developed with the aim to replace the multitude of customised sensors used so far in scanning and pointing mechanisms. It will become the European standard nano-measuring system qualified for space mechanisms operating in closed loop control. The HRSPS offers either two independent single or a differential output(s) offering a resolution of 1 nanometer. Three different HRSPS covering three measuring ranges have been developed. This paper presents the test results and the final confirmation of the performances of the HRSPS. The majority of sensor designs available industrially and in the launcher field are not readily suitable for high reliability space / satellite applications. The HRSPS manufactured can be supplied in either high reliability FM's for satellites and also FM's for microgravity / ISS applications requiring Mil 883B/C type of components. The paper will present the first applications for microgravity and satellite applications.

Aeby, Hans-Peter; Blaser, Roger; Mancini, Nicolas; Mivelaz, Marcel; Perriard, Jacques

2001-09-01

160

Proximal femoral focal deficiency: a clinical appraisal.  

PubMed

In patients with unilateral proximal femoral focal deficiency, the leg length inequality is almost always greater than five inches at skeletal maturity. Consequently, prosthetic management should be planned before the patient walks. A standard plan of treatment of the patient with unilateral PFFD is not possible at this time, primarily because of the varying percentage of femur missing and the controversy of management of the hip in patients with type A or B deformity. However, we found that ankle disarticulation with Syme flap closure combined with arthrodesis of the knee is a reasonable plan in many patients with unilateral PFFD. This allows correction of the knee and hip flexion contractures and gives the patient a functional, cosmetic stump. By the time he begins school, he is functioning as an above-knee amputee. This is not an undesirable goal, as one of us (E.G.R.) recently examined an above-knee amputee, a Captain in the United States Army, who continued his hobby of sky diving. PMID:424795

Richardson, E G; Rambach, B E

1979-02-01

161

Affective effects of agent proximity in conversational systems  

Microsoft Academic Search

The aim of this study was to investigate, if the simulated proximity level of an anthropomorphic conversational agent and the affective contents in the agent's speech influence the subjects' affective experiences. Eight subjects were exposed to messages given by the agent using synthetic speech. The agent character's simulated proximity level (intimate, personal, social, and public) and the affective contents of

Timo Partala; Veikko Surakka; Jussi Lahti

2004-01-01

162

Proximal jejunal intussusception associated with a long tube  

Microsoft Academic Search

An intussusception of the small intestine in association with a long tube usually occurs in the vicinity of the mercury-filled bag and can be visualized radiographically by instilling barium directly into the tube. On rare occasions, an intussusception develops in the proximal jejunum and is difficult to recognize. We report the fifth and sixth cases of a proximal jejunal intussusception

Steven R. Peskin; R. Eugene Langevin; Peter A. Banks

1986-01-01

163

P-FCM: a proximity -- based fuzzy clustering  

Microsoft Academic Search

In this study, we introduce and study a proximity-based fuzzy clustering. As the name stipulates, in this mode of clustering, a structure “discovery” in the data is realized in an unsupervised manner and becomes augmented by a certain auxiliary supervision mechanism. The supervision mechanism introduced in this algorithm is realized via a number of proximity “hints” (constraints) that specify an

Witold Pedrycz; Vincenzo Loia; Sabrina Senatore

2004-01-01

164

Total knee arthroplasty in the management proximal tibial stress fractures  

Microsoft Academic Search

Five patients with stress fractures of the proximal tibia adjacent to an arthritic knee joint were treated by resurfacing arthroplasty with intramedullary fixation of the fracture. All five fractures healed and limb realignment was achieved. The literature concerning proximal tibial stress structures in relation to the arthritic knee and the management of this condition is reviewed.

M. P. W. Tomlinson; I. M. Dingwall; H. Phillips

1995-01-01

165

Sodium Movement across Single Perfused Proximal Tubules of Rat Kidneys  

Microsoft Academic Search

Using perfusion techniques in single proximal tubule segments of rat kidney, the relationship between net sodium movement and active transport of ions, as measured by the short-circuit method, has been studied. In addition, the role of the colloid-osmotic pressure gradient in proximal transtubular fluid and sodium movement has been considered. Furthermore, the limiting concen- tration gradient against which sodium movement

GERHARD GIEBISCH; RUTH M. KLOSE; GERHARD MALNIC; W. JAMES SULLIVAN; ERICH E. WINDHAGER

1964-01-01

166

Efficient computation of a proximity matching in spatial databases  

Microsoft Academic Search

Spatial data mining recently emerges from a number of real applications, such as realestate marketing, urban planning, weather forecasting, medical image analysis, road traffic accident analysis, etc. It demands for efficient solutions for many new, expensive, and complicated problems. In this paper, we investigate a proximity matching problem among clusters and features. The investigation involves proximity relationship measurement between clusters

Xuemin Lin; Xiaomei Zhou; Chengfei Liu

2000-01-01

167

Proximity and territory versus space in regional science  

Microsoft Academic Search

Empirical evidence tends to show that regional development occurs only in certain places. Therefore, one can ask the central question of the role of physical proximity in economic development processes. Economists try to answer this question through the concept of externalities, but this does not explain why certain externalities are linked with physical proximity. In this paper the author tries

O Crevoisier

1996-01-01

168

Intralysosomal digestion of lysozyme in renal proximal tubule cells  

Microsoft Academic Search

Intralysosomal digestion of lysozyme in renal proximal tubule cells. This investigation was carried out to determine the ability of lysosomes in intact proximal tubule cells to digest absorbed protein. Lysozyme labeled with 125I was injected i.v. into rats and renal cortical slices removed after one hour. The slices were incubated in vitro for up to two hours. The location of

Erik Ilsø Christensen; Arvid B Maunsbach

1974-01-01

169

Erythromycin enhances fasting and postprandial proximal gastric tone in humans  

Microsoft Academic Search

Background & Aims: Low doses of erythromycin induce antral contractions and accelerate gastric emptying. However, the effect of erythromycin on the proximal stomach remains unknown. The aim of this study was to assess the effect and mechanism(s) of action of erythromycin on proximal gastric tone in humans. Methods: Gastric tone was measured using an electronic barostat in two groups of

Stanislas Bruley des Varannes; Véronique Parys; Alain Ropert; Jean Alain Chayvialle; Claude Rozé; Jean Paul Galmiche

1995-01-01

170

75 FR 5009 - Proximity Detection Systems for Underground Mines  

Federal Register 2010, 2011, 2012, 2013

...RCCM using radio waves or a cable. Moving...Virginia Mine Safety Technology Task Force (Task...including shuttle cars, scoops, belt...proximity detection technology to underground mobile...RCCMs and shuttle cars. In your experience...proximity warning technology. Include any...

2010-02-01

171

Proximal Probes Based Nanorobotic Drawing of Polymer Micro\\/Nanofibers  

Microsoft Academic Search

This paper proposes a nanorobotic fiber fabrication method which uses proximal probes to draw polymer fibers down to few hundred nanometers in diameter and several hundred micrometers in length. Using proximal probes such as Atomic Force Microscope (AFM) and Scanning Tunneling Microscope (STM) or glass micropipettes, liquid polymers dissolved in a solvent are drawn. During drawing, the solvent evaporates in

Amrinder Singh Nain; Cristina Amon; Metin Sitti

2006-01-01

172

Proximity-based access control for implantable medical devices  

Microsoft Academic Search

We proposea proximity-based access control scheme forimplantable medical devices (IMDs). Ourscheme is based onultrasonic distance- bounding and enables an implanted medical device to grant access to its resources only to those devices that are in its close proxim- ity. We demonstrate the feasibility of our approach through tests in an emulated patient environment. We show that, although im- planted, IMDs

Kasper Bonne Rasmussen; Claude Castelluccia; Thomas S. Heydt-benjamin; Srdjan Capkun

2009-01-01

173

How Peer Proximity Moderates Indirect Media Influence on Adolescent Smoking  

Microsoft Academic Search

This study examines direct and indirect impacts of antismoking media messages on adolescents' smoking attitudes and intentions to smoke. Elaborating on the influence of presumed influence model, this study incorporates the moderating role of peer proximity (i.e., proximal versus distal peers). Analyzing direct effects in a survey of 1,687 middle school students, we find that antismoking media messages have unexpected

Hye-Jin Paek; Albert C. Gunther

2007-01-01

174

Spot image processing and simulation of the laser proximity fuze  

Microsoft Academic Search

This paper investigates the problems of the large beam divergence angle and short detection range in the launch system of laser proximity fuze. By analyzing the factors of measuring distance in laser proximity fuze, combined with characteristics of laser's far-field divergence angle, and according to aspheric optical design theory, we carry out image processing and simulation of laser spot by

Lin Gan; He Zhang; Xiang-jin Zhang

2011-01-01

175

Palliation of proximal malignant biliary obstruction by endoscopic endoprosthesis insertion  

Microsoft Academic Search

For four years up to December 1987, 190 patients (median age 73 years) with proximal malignant biliary obstruction were treated by endoscopic endoprosthesis insertion. Altogether 101 had cholangiocarcinoma, 21 gall bladder carcinoma, 20 local spread of pancreatic carcinoma, and 48 metastatic malignancy. Fifty eight patients had type I, 54 type II, and 78 type III proximal biliary strictures (Bismuth classification).

A A Polydorou; S R Cairns; J F Dowsett; A R Hatfield; P R Salmon; P B Cotton; R C Russell

1991-01-01

176

Does Distance Still Matter? Geographic Proximity and New Product Development  

Microsoft Academic Search

Many firms rely on external organizations to acquire knowledge that is useful for developing creative new products and reducing the time needed to bring these products to market. Cluster theory suggests that this knowledge is often obtained from organizations located in close geographic proximity. Specifically, proximity is assumed to fos- ter heightened face-to-face communication, strengthened relational ties, increased knowledge acquisition,

Shankar Ganesan; Alan J. Malter; Aric Rindfleisch

2005-01-01

177

The Increasing Importance of Geographical Proximity in Technological Innovation  

Microsoft Academic Search

In spite of increasing global flows of ideas, capital, goods and labor, recent research in urban economics and economic geography suggests that geographical proximity between innovators may be important to technological innovation. Many authors also claim that the rise of a knowledge-based economy and changes in the organization of the innovation process have actually increased the value of such proximity

Jung Won Sonn

178

Role of TASK2 Potassium Channels Regarding Volume Regulation in Primary Cultures of Mouse Proximal Tubules  

PubMed Central

Several papers reported the role of TASK2 channels in cell volume regulation and regulatory volume decrease (RVD). To check the possibility that the TASK2 channel modulates the RVD process in kidney, we performed primary cultures of proximal convoluted tubules (PCT) and distal convoluted tubules (DCT) from wild-type and TASK2 knockout (KO) mice. In KO mice, the TASK2 coding sequence was in part replaced by the lac-Z gene. This allows for the precise localization of TASK2 in kidney sections using ?-galactosidase staining. TASK2 was only localized in PCT cells. K+ currents were analyzed by the whole-cell clamp technique with 125 mM K-gluconate in the pipette and 140 mM Na-gluconate in the bath. In PCT cells from wild-type mice, hypotonicity induced swelling-activated K+ currents insensitive to 1 mM tetraethylammonium, 10 nM charybdotoxin, and 10 ?M 293B, but blocked by 500 ?M quinidine and 10 ?M clofilium. These currents were increased in alkaline pH and decreased in acidic pH. In PCT cells from TASK2 KO, swelling-activated K+ currents were completely impaired. In conclusion, the TASK2 channel is expressed in kidney proximal cells and could be the swelling-activated K+ channel responsible for the cell volume regulation process during osmolyte absorptions in the proximal tubules.

Barriere, Herve; Belfodil, Radia; Rubera, Isabelle; Tauc, Michel; Lesage, Florian; Poujeol, Chantal; Guy, Nicolas; Barhanin, Jacques; Poujeol, Philippe

2003-01-01

179

Seasonal Micro and MacroMineral Profile and Proximate Composition of Oyster ( Ostrea edulis ) Analyzed by ICP-MS  

Microsoft Academic Search

Oysters (Ostrea edulis) were investigated for micro–macro-mineral content and proximate composition throughout the year. Mercury, lead and aluminium\\u000a were found to be below the legislative limits, while zinc was over throughout the year. Cadmium and copper were over legislative\\u000a limits in winter. While the highest Na, Mg and Ca values were found in autumn, the highest K and P contents

Nuray Erkan; Özkan Özden; ?afak Ulusoy

2011-01-01

180

Verification of optical proximity effect in immersion lithography  

NASA Astrophysics Data System (ADS)

193 nm lithography is one of the most promising technologies for next-generation lithography and is being actively evaluated for making it practicable (1,2). First, we evaluated an immersion lithography tool (engineering evaluation tool (EET)) (3) and a dry lithography tool (S307E) with the same numerical aperture (NA = 0.85), manufactured by Nikon Corporation. As a result, an increase in the depth of focus (DOF) of the EET to 200 nm in comparison with the DOF (110 nm) of the dry exposure tool was confirmed in a 90 nm isolated space pattern. Next, the optical proximity effect (OPE) in this pattern was evaluated. Generally, when an immersion lithography tool is compared with a dry one with the same NA or both the tools, only an increase in the DOF is found. However, we confirmed that the OPE (The OPE of the 90 nm isolated space pattern is defined as the difference in the space width between a dense space and an isolated space.) of the dry exposure tool for the 90 nm isolated space pattern reduced from 33.1 nm to 14.1 nm by immersion lithography. As the effect of the reduction of 19 nm, the OPE reduced to 15.2 nm by the effect of the top coatings (TCs) and to 3.8 nm by the optical characteristics. An impact of about 5 nm on the OPE was confirmed by the process parameters-film thickness and the pre-bake temperature of the TC. In the case that the solvent was replaced with a high boiling point solvent, the impact changed from 5 to 20 nm further, the replacement of the solvent had a considerable impact on the OPE. However, this influence differs considerably according to the kind of resists; further, it was shown that the addition of acid materials and a change in the polymer base resulted in a high impact on the OPE for a certain resist. Thus, it was demonstrated that the selection of TC is very important for the OPE in immersion lithography.

Suganaga, Toshifumi; Maejima, Shinroku; Hanawa, Tetsuro; Ishibashi, Takeo; Nakao, Shuji; Shirai, Seiichiro; Narimatsu, Koichiro; Suko, Kazuyuki; Shiraishi, Kenichi; Ishii, Yuki; Ando, Tomoyuki; Ohmori, Katsumi

2006-04-01

181

Proximal humeral reconstruction using nail cement spacer in primary and metastatic tumours of proximal humerus.  

PubMed

Limb salvage surgery for malignant tumours of proximal humerus is an operative challenge, where the surgeon has to preserve elbow and hand functions and retain shoulder stability with as much function as possible. We treated 14 consecutive patients with primary malignant or isolated metastasis of proximal humerus with surgical resection and reconstruction by nail cement spacer. There were 8 females and 6 males, with a mean age of 28.92 years (range 16-51 years) and a mean follow-up of 30.14 months (range 12-52 months). The diagnosis was osteosarcoma in 8 patients, chondrosarcoma in 4 patients and metastasis from thyroid and breast carcinoma in 1 patient each. One of our patients had radial nerve neuropraxia, 1 developed inferior subluxation and 3 developed distant metastasis. Two patients died of disease and one developed local recurrence leading to forequarter amputation, leaving a total of 11 patients with functional extremities for assessment at the time of final follow-up which was done using the Musculoskeletal Tumour Society (MSTS) score. Though we were able to preserve the elbow, wrist and hand functions in all patients, the abductor mechanism, deltoid muscle and axillary nerve were not salvageable in any of cases. The mean MSTS score at the time of final follow-up was 19.09. Thus, proximal humeral reconstruction using nail cement spacer is a technical simple, cost-effective and reproducible procedure which makes it a reliable option in subset of patients where the functions around the shoulder cannot be preserved despite costlier prosthesis. PMID:23925868

Kundu, Zile Singh; Gogna, Paritosh; Gupta, Vinay; Kamboj, Pradeep; Singla, Rohit; Sangwan, Sukhbir Singh

2013-08-08

182

Evidence of chloride\\/bicarbonate exchange mediating bicarbonate efflux from S3 segments of rabbit renal proximal tubule  

Microsoft Academic Search

The mechanism of HCO\\u000a 3\\u000a ?\\u000a exit from rabbit renal proximal tubule S3 segments was investigated. Isolated tubules were perfused luminally and peritubularly\\u000a with test solutions and cell pH (pHi), cell Cl? activity ([Cl?]i) and cell Na+ activity ([Na+]i) were measured with ion-selective microelectrodes. From the response of pHi and [Cl?]i to changes in bath Cl? or HCO\\u000a 3\\u000a ?

Y. Kondo; E. Frömter

1990-01-01

183

Nanocrystal Bioassembly: Asymmetry, Proximity, and Enzymatic Manipulation  

SciTech Connect

Research at the interface between biomolecules and inorganic nanocrystals has resulted in a great number of new discoveries. In part this arises from the synergistic duality of the system: biomolecules may act as self-assembly agents for organizing inorganic nanocrystals into functional materials; alternatively, nanocrystals may act as microscopic or spectroscopic labels for elucidating the behavior of complex biomolecular systems. However, success in either of these functions relies heavily uponthe ability to control the conjugation and assembly processes.In the work presented here, we first design a branched DNA scaffold which allows hybridization of DNA-nanocrystal monoconjugates to form discrete assemblies. Importantly, the asymmetry of the branched scaffold allows the formation of asymmetric2assemblies of nanocrystals. In the context of a self-assembled device, this can be considered a step toward the ability to engineer functionally distinct inputs and outputs.Next we develop an anion-exchange high performance liquid chromatography purification method which allows large gold nanocrystals attached to single strands of very short DNA to be purified. When two such complementary conjugates are hybridized, the large nanocrystals are brought into close proximity, allowing their plasmon resonances to couple. Such plasmon-coupled constructs are of interest both as optical interconnects for nanoscale devices and as `plasmon ruler? biomolecular probes.We then present an enzymatic ligation strategy for creating multi-nanoparticle building blocks for self-assembly. In constructing a nanoscale device, such a strategy would allow pre-assembly and purification of components; these constructs can also act as multi-label probes of single-stranded DNA conformational dynamics. Finally we demonstrate a simple proof-of-concept of a nanoparticle analog of the polymerase chain reaction.

Claridge, Shelley A

2008-05-01

184

Missense mutation T485S alters NBCe1-A electrogenicity causing proximal renal tubular acidosis.  

PubMed

Mutations in SLC4A4, the gene encoding the electrogenic Na(+)-HCO3(-) cotransporter NBCe1, cause severe proximal renal tubular acidosis (pRTA), growth retardation, decreased IQ, and eye and teeth abnormalities. Among the known NBCe1 mutations, the disease-causing mechanism of the T485S (NBCe1-A numbering) mutation is intriguing because the substituted amino acid, serine, is structurally and chemically similar to threonine. In this study, we performed intracellular pH and whole cell patch-clamp measurements to investigate the base transport and electrogenic properties of NBCe1-A-T485S in mammalian HEK 293 cells. Our results demonstrated that Ser substitution of Thr485 decreased base transport by ~50%, and importantly, converted NBCe1-A from an electrogenic to an electroneutral transporter. Aqueous accessibility analysis using sulfhydryl reactive reagents indicated that Thr485 likely resides in an NBCe1-A ion interaction site. This critical location is also supported by the finding that G486R (a pRTA causing mutation) alters the position of Thr485 in NBCe1-A thereby impairing its transport function. By using NO3(-) as a surrogate ion for CO3(2-), our result indicated that NBCe1-A mediates electrogenic Na(+)-CO3(2-) cotransport when functioning with a 1:2 charge transport stoichiometry. In contrast, electroneutral NBCe1-T485S is unable to transport NO3(-), compatible with the hypothesis that it mediates Na(+)-HCO3(-) cotransport. In patients, NBCe1-A-T485S is predicted to transport Na(+)-HCO3(-) in the reverse direction from blood into proximal tubule cells thereby impairing transepithelial HCO3(-) absorption, possibly representing a new pathogenic mechanism for generating human pRTA. PMID:23636456

Zhu, Quansheng; Shao, Xuesi M; Kao, Liyo; Azimov, Rustam; Weinstein, Alan M; Newman, Debra; Liu, Weixin; Kurtz, Ira

2013-05-01

185

Long-term regulation of proximal tubule acid-base transporter abundance by angiotensin II.  

PubMed

In the proximal tubule, angiotensin II (Ang-II) regulates HCO(-)(3) reabsorption and H+ secretion by binding the type 1 Ang-II (AT1) receptor, stimulating Na(+)/HCO(-)(3) cotransport and Na(+)/H(+) exchange. Studies were carried out to determine if long-term changes in Ang-II receptor occupation alter the abundance of the basolateral Na(+)/HCO(-)(3) cotransporter (NBC1) or the apical membrane type 3 Na(+)/H(+) exchanger (NHE3). In the first set of experiments, rats eating a low-sodium diet were infused with the AT1 blocker, candesartan, or vehicle. In the second, lisinopril-infused rats were infused with either Ang II or vehicle. Transporter abundances were determined in whole kidney homogenates (WKH) and in brush border membrane (BBM) preparations by semiquantitative immunoblotting. Tissue distribution of transporters was assessed by immunocytochemistry. Blockade of the AT1 receptor by candesartan caused decreased abundance of NBC1 in WKH (59 +/- 9% of control; P<0.05) and Ang-II infusion increased abundance (130 +/- 7% of control; P<0.05). Changes in NBC1 in response to candesartan were confirmed immunohistochemically. Neither candesartan nor Ang II infusion affected the abundance of NHE3 in WKH or cortical homogenates. Candesartan decreased type 2 sodium-phosphate cotransporter abundance in both WKH (52 +/- 7% of control; P<0.05) and BBM (32 +/- 7% of control; P<0.05). Serum bicarbonate was decreased by candesartan and increased by Ang-II. Candesartan also decreased urinary ammonium excretion (P<0.05). The long-term effects of Ang-II in the proximal tubule may be mediated in part by regulation of NBC1 abundance, modifying bicarbonate reabsorption. PMID:16807546

Turban, S; Beutler, K T; Morris, R G; Masilamani, S; Fenton, R A; Knepper, M A; Packer, R K

2006-08-01

186

Dual pathology proximal median nerve compression of the forearm.  

PubMed

We report an unusual case of synchronous pathology in the forearm- the coexistence of a large lipoma of the median nerve together with an osteochondroma of the proximal ulna, giving rise to a dual proximal median nerve compression. Proximal median nerve compression neuropathies in the forearm are uncommon compared to the prevalence of distal compression neuropathies (eg Carpal Tunnel Syndrome). Both neural fibrolipomas (Refs. 1,2) and osteochondromas of the proximal ulna (Ref. 3) in isolation are rare but well documented. Unlike that of a distal compression, a proximal compression of the median nerve will often have a definite cause. Neural fibrolipoma, also called fibrolipomatous hamartoma are rare, slow-growing, benign tumours of peripheral nerves, most often occurring in the median nerve of younger patients. To our knowledge, this is the first report of such dual pathology in the same forearm, giving rise to a severe proximal compression of the median nerve. In this case, the nerve was being pushed anteriorly by the osteochondroma, and was being compressed from within by the intraneural lipoma. This unusual case highlights the advantage of preoperative imaging as part of the workup of proximal median nerve compression. PMID:23707555

Murphy, Siun M; Browne, Katherine; Tuite, David J; O'Shaughnessy, Michael

2013-05-23

187

Characterisation of human tubular cell monolayers as a model of proximal tubular xenobiotic handling  

SciTech Connect

The aim of this study was to determine whether primary human tubular cell monolayers could provide a powerful tool with which to investigate the renal proximal tubular handling of xenobiotics. Human proximal and distal tubule/collecting duct cells were grown as monolayers on permeable filter supports. After 10 days in culture, proximal tubule cells remained differentiated and expressed a wide palette of transporters at the mRNA level including NaPi-IIa, SGLT1, SGLT2, OCT2, OCTN2, OAT1, OAT3, OAT4, MDR1, MRP2 and BCRP. At the protein level, the expression of a subset of transporters including NaPi-IIa, OAT1 and OAT3 was demonstrated using immunohistochemistry. Analysis of the expression of the ATP binding cassette efflux pumps MDR1, MRP2 and BCRP confirmed their apical membrane localisation. At the functional level, tubule cell monolayers retain the necessary machinery to mediate the net secretion of the prototypic substrates; PAH and creatinine. PAH secretion across the monolayer consisted of the uptake of PAH across the basolateral membrane by OAT1 and OAT3 and the apical exit of PAH by a probenecid and MK571-sensitive route consistent with actions of MRP2 or MRP4. Creatinine secretion was by OCT2-mediated uptake at the basolateral membrane and via MDR1 at the apical membrane. Functional expression of MDR1 and BCRP at the apical membrane was also demonstrated using a Hoechst 33342 dye. Similarly, measurement of calcein efflux demonstrated the functional expression of MRP2 at the apical membrane of cell monolayers. In conclusion, human tubular cell monolayers provide a powerful tool to investigate renal xenobiotic handling.

Brown, Colin D.A. [Epithelial Research Group, Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH (United Kingdom)], E-mail: c.d.a.brown@ncl.ac.uk; Sayer, Rachel; Windass, Amy S.; Haslam, Iain S. [Epithelial Research Group, Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH (United Kingdom); Broe, Marc E. de; D'Haese, Patrick C.; Verhulst, Anja [Laboratory of Pathophysiology, University of Antwerp (Belgium)

2008-12-15

188

Multiple proximities: culture and geography in the transport logistics of newsprint manufactured in Australia  

Microsoft Academic Search

Three types of proximity are argued to be present in the research material in this paper. First, put simply, geographic proximity refers to two entities being physically next to each other. Second, cultural proximity refers to two entities being relationally close to one another, with geographic proximity often not being required. Third, network proximity refers to two entities being associated

Matt Bradshaw

2001-01-01

189

A 17 year old with isolated proximal tibiofibular joint arthritis  

PubMed Central

The proximal tibiofibular joint (TFJ) is rarely affected in rheumatic diseases, and we frequently interpret pain of the lateral knee as the result of overuse or trauma. Nonetheless, the TFJ is a synovial joint that communicates with the tibiofemoral joint in a proportion of patients. While proximal TFJ arthritis has been rarely associated with existing spondyloarthritis, isolated TFJ arthritis as the presenting manifestation of spondyloarthritis has not yet been described. Here, we report the clinical and radiographic presentation of an adolescent with chronic proximal TFJ arthritis heralding spondyloarthritis highly suggestive of ankylosing spondylitis.

2013-01-01

190

NaPi-IIa and interacting partners  

PubMed Central

Regulation of renal proximal tubular reabsorption of phosphate (Pi) is one of the critical steps in Pi homeostasis. Experimental evidence suggests that this regulation is achieved mainly by controlling the apical expression of the Na+-dependent Pi cotransporter type IIa (NaPi-IIa) in proximal tubules. Only recently have we started to obtain information regarding the molecular mechanisms that control the apical expression of NaPi-IIa. The first critical observation was the finding that truncation of only its last three amino acid residues has a strong effect on apical expression. A second major finding was the observation that the last intracellular loop of NaPi-IIa contains sequence information that confers parathyroid hormone (PTH) sensitivity. The use of the above domains of the cotransporter in yeast two-hybrid (Y2H) screening allowed the identification of proteins interacting with NaPi-IIa. Biochemical and morphological, as well as functional, analyses have allowed us to obtain insights into the physiological roles of such interactions, although our present knowledge is still far from complete.

Hernando, N; Gisler, SM; Pribanic, S; Deliot, N; Capuano, P; Wagner, CA; Moe, OW; Biber, J; Murer, H

2005-01-01

191

Intraosseous lipomas with reactive ossification in the proximal femur  

SciTech Connect

Eight operated or post mortem cases of intraosseous lipomas of the proximal femur are described. Radiographic dense calcification may be present. Four distinctive pathologic features differentiate this lesion from other entities.

Milgram, J.W.

1981-10-01

192

Perinatal mortality and residential proximity to an industrial park.  

PubMed

The authors' objective was to determine whether residential proximity to an industrial park (IP) is associated with increased perinatal mortality (PM). This semiecological study included 63,850 delivered births with 840 cases of PM (1995-2000). The authors categorized the study populations by ethnicity (ie, Bedouin and Jewish) and type of locality. Residential distance from the IP served as a surrogate indicator of exposure. Among Bedouin newborns, proximity to the IP was associated with increased PM rates (relative risk = 1.45; 95% confidence interval = 1.22-1.72). The excess in PM was not related to maternal or newborn physical characteristics that the authors observed. The risk of PM and its components in the Jewish localities was not associated with IP proximity. The association between residential proximity to the IP and excess in PM among only Bedouin newborns may be related to vulnerability caused by the nomadic nature of the society. PMID:18479994

Sarov, Batia; Bentov, Yaakov; Kordysh, Ella; Karakis, Isabella; Bolotin, Arkady; Hershkovitz, Reli; Belmaker, Ilana

2008-01-01

193

Contoured plating for proximal ulna nonunion: an improved technique  

PubMed Central

Twenty-one patients having proximal ulna nonunion were treated with contoured plating. The most proximal hole received an intramedullary 6.5-mm cancellous lag screw that extends fixation of the nonunion site. Mean age of the patients was 41.7 years. Average follow-up period was 22 months. Union occurred in 19 cases after a mean of 9.6 weeks. Complications were persistent nonunion in two cases, a stiff elbow in one, hardware prominence in two, and a 1×1-cm ulcer over the curve of the plate in one case. The two unsatisfactory results were related to ulnohumeral arthritis. In conclusion, augmentation of the contoured plate with a 6.5-mm intramedullary cancellous lag screw creates a stable construct in treatment of proximal ulna nonunion. It applies axial compression, resists bending forces on the dorsal plate and allows early mobilization after surgery, regardless of the size of the proximal fragment.

Elsayed, Mohamed; Seleem, Osama

2009-01-01

194

Interracial Ratios and Proximity in Dormitories: Attitudes of University Students  

ERIC Educational Resources Information Center

|A survey technique was used to investigate black and white undergraduate students' attitudes toward the minimum number of one's own race needed for comfort in dormitory residency and the relationship of proximity of one's race toward this number. (MLB)|

Bennett, Don C.

1974-01-01

195

In vivo genetic selection of renal proximal tubules.  

PubMed

Repopulation by transplanted cells can result in effective therapy for several regenerative organs including blood, liver, and skin. In contrast, cell therapies for renal diseases are not currently available. Here we developed an animal model in which cells genetically resistant to a toxic intermediate of tyrosine metabolism, homogentisic acid (HGA), were able to repopulate the damaged proximal tubule epithelium of mice with fumarylacetoacetate hydrolase (Fah) deficiency. HGA resistance was achieved by two independent mechanisms. First, Fah+ transplanted bone marrow cells produced significant replacement of damaged proximal tubular epithelium (up to 50%). The majority of bone marrow-derived epithelial cells were generated by cell fusion, not transdifferentiation. In addition to regeneration by fusion-derived epithelial cells, proximal tubular repopulation was also observed by host epithelial cells, which had lost the homogentisic acid dioxygenase gene. These data demonstrate that extensive regeneration of the renal proximal tubule compartment can be achieved through genetic selection of functional cells. PMID:16216560

Held, Patrice K; Al-Dhalimy, Muhsen; Willenbring, Holger; Akkari, Yassmine; Jiang, Shuguang; Torimaru, Yumi; Olson, Susan; Fleming, William H; Finegold, Milton; Grompe, Markus

2005-10-10

196

Stress Injury of the Proximal Ulna in Professional Baseball Players  

Microsoft Academic Search

Background: To date, stress injury of the proximal ulna has been infrequently reported as a cause of elbow pain in the throwing athlete.Purpose: We describe a syndrome of osseous stress injury of the proximal ulna in the professional throwing athlete.Study Design: Retrospective review.Methods: We evaluated the clinical, radiographic, and magnetic resonance imaging findings of seven professional baseball players with osseous

Mark S. Schickendantz; Charles P. Ho; Jason Koh

2002-01-01

197

Proximate time-optimal control of third-order servomechanisms  

Microsoft Academic Search

The problem of proximate time-optimal control of third-order systems is considered. Two proximate time-optimal servomechanisms, PTO53 and PTO53?, are proposed for type-3 and type-2 third-order plants, respectively. Theorems stating sufficient conditions on each system's control design parameters to ensure global stability are given, and it is shown that the control parameters can be adjusted to accommodate, more or less, disturbances

L. Y. Pao; G. F. Franklin

1993-01-01

198

Does tamsulosin change the management of proximally located ureteral stones?  

Microsoft Academic Search

The objective of this study is to assess the efficacy of an alpha-1 adrenergic receptor blocking agent on the spontaneous\\u000a passage of proximal ureteral calculi ?10 mm. 92 patients having single radio-opaque proximal ureteral stone ?10 mm were randomized\\u000a into two groups. Group 1 patients (n = 50) were followed with classical conservative approach and patients in Group 2 (n = 42) additionally received tamsulosin, 0.4 mg\\/day

Faruk Yencilek; Sak?p Erturhan; Onder Canguven; Hakan Koyuncu; Bulent Erol; Kemal Sarica

2010-01-01

199

Axillary artery injury as a complication of proximal humerus fractures  

Microsoft Academic Search

Proximal humerus fractures are common injuries and represent approximately 5% of all fractures.10, 14, 21 These fractures are infrequently associated with neurovascular injuries. Brachial plexus injuries are uncommon,18 whereas axillary artery injuries are rare.5–9, 11, 12, 16–20, 22–24 A review of 19 previously reported cases of axillary artery injury after proximal humerus fracture revealed that 84% occurred in patients older

John A McLaughlin; Ronald Light; Irving Lustrin

1998-01-01

200

Exploring the role of proximity in SME knowledge-acquisition  

Microsoft Academic Search

Knowledge-acquisition activities of small- and medium-sized enterprises (SMEs) are assumed to benefit from geographic proximity to similar firms and centres of research excellence. This paper will explore the knowledge-acquisition processes and critical interfaces of innovative SMEs and outline factors that contributed to an observed lack of geographic proximity-based knowledge search activity. A growth path based upon innovation driven, rapid internationalisation

Sally Davenport

2005-01-01

201

NA and optimization for high-NA i-line lithography  

NASA Astrophysics Data System (ADS)

NA and (sigma) will be optimized to establish 0.35 micrometers i-line single layer resist process without use of super resolution techniques. Resolution, depth of focus (DOF), and proximity effect are evaluated using a variable NA and (sigma) stepper. NA is varied by an aperture stop in a projection lens. (sigma) is varied by not only an aperture stop (mechanical (sigma) ) in an illumination optics but also intensity distribution of illumination at the aperture stop (effective (sigma) ). Optimized NA and (sigma) are applied to a newly developed high resolution resist. Obtained results show that high NA and high (sigma) stepper has a great availability for 0.35 micrometers device fabrication.

Yamanaka, Koji; Iwasaki, Haruo; Nozue, Hiroshi; Kasama, Kunihiko

1993-08-01

202

Design and Clinical Application of Proximal Humerus Memory Connector  

NASA Astrophysics Data System (ADS)

Treatment for comminuted proximal humerus fractures and nonunions are a substantial challenge for orthopedic surgeons. Plate and screw fixation does not provide enough stability to allow patients to begin functional exercises early after surgery. Using shape memory material nickel titanium alloy, we designed a new device for treating severe comminuted proximal humerus fractures that accommodates for the anatomical features of the proximal humerus. Twenty-two cases of comminuted fracture, malunion, and nonunion of the proximal humerus were treated with the proximal humeral memory connector (PHMC). No external fixation was needed after the operation and patients began active shoulder exercises an average of 8 days after the operation. Follow-up evaluation (mean 18.5 months) revealed that bone healing with lamellar bone formation occurred an average of 3.6 months after surgery for the fracture cases and 4.5 months after surgery for the nonunion cases. Average shoulder function was 88.5 according to the criteria of Michael Reese. PHMC is an effective new device to treat comminuted proximal humerus fractures and nonunions. The use of this device may reduce the need for shoulder joint arthroplasty.

Xu, Shuo-Gui; Zhang, Chun-Cai

2011-02-01

203

Transimmortalized proximal tubule and collecting duct cell lines derived from the kidneys of transgenic mice.  

PubMed

This review summarizes the strategy of cellular immortalization based on the principle of targeted oncogenesis in transgenic mice, used to establish models of transimmortalized renal proximal tubule cells, referred to as PKSV-PCT and PKSV-PR-cells, and collecting duct principal cells, referred to as mpkCCD(cl4) cells. These cell lines have maintained for long-term passages the main biochemical and functional properties of the parental cells from which they were derived. Proximal tubule PKSV-PCT and PKSV-PR cells have been proved to be suitable cell systems for toxicological and pharmacological studies. They also permitted the establishment of a model of multidrug-resistant (MDR) renal epithelial tubule cells, PKSV-PR(col50), which have served for the study of both MDR-dependent extrusion of chemotherapeutic drugs and inappropriate accumulation of weak base anthracyclines in intracellular acidic organelles. The novel collecting duct cell line mpkCCD(cl4), which has maintained the characteristics of tight epithelial cells, in particular Na(+) absorption stimulated by aldosterone, has been extensively used for pharmacological studies related to the regulation of ion transport. These cells have permitted the identification of several aldosterone-induced proteins playing a key role in the regulation of Na(+) absorption mediated by the epithelial Na(+) channel ENaC. Recent studies have also provided evidence that these cell lines represent valuable cell systems for the study of host-pathogen interactions and the analysis of the role of renal tubule epithelial cells in the induction of inflammatory response caused by uropathogens that may lead to severe renal damage. PMID:17219250

Chassin, C; Bens, M; Vandewalle, A

2007-01-11

204

Ejecta emplacement: from distal to proximal  

NASA Astrophysics Data System (ADS)

Introduction Most part of impact ejecta is deposited ballistically at some distance from a crater, defined by ejection velocity V and ejection angle ?: d=v2sin?/g. In case of giant impacts, planetary curvature should be taken into account [1]. Combined with ejecta scaling [2], these relations allow to define ejecta thickness as a function of distance. Ejecta from large craters are deposited at velocity high enough to mobilize substrate material and to thicken ejecta deposits [3]. Ballistic approximation is valid for airless bodies (if impact vaporization is not vast) or for proximal ejecta of large impact craters, where ejecta mass per unit area is substantially greater than the mass of involved vapor/atmosphere (M-ratio). Deposition of distal ejecta, in which ejecta mass is negligible compared to the atmosphere, may be also treated in a simplified manner, i.e. as 1) passive motion of ejected particles within an impact plume and 2) later, as sedimentation of particles in undisturbed atmosphere (equilibrium between gravity and drag). In all intermediate M-ratio values, impact ejecta move like a surge, i.e. dilute suspension current in which particles are carried in turbulent flows under the influence of gravity. Surges are well-known for near-surface explosive tests, described in detail for volcanic explosions (Plinian column collapse, phreato-magmatic eruption, lateral blast), and found in ejecta from the Chicxulub [4] and the Ries [5]. Important aspects of surge transport include its ability to deposit ejecta over a larger area than that typical of continuous ballistic ejecta and to create multiple ejecta layers. Numerical model Two-phase hydrodynamics. Surges should be modeled in the frame of two-phase hydrodynamics, i.e. interaction between solid/molten particles and atmospheric gas/impact vapor should be taken into account. There are two techniques of solving equations for dust particle motion in a gas flow. The first one describes solid/molten particles as a liquid with specific properties, i.e. finite-difference equations are the same as in standard hydrodynamics [6-8]. Another approach is based on solving equations of motion for representative particles [9]. Each of these markers describes the motion of a large number of real particles with similar sizes, velocities, and trajectories. Equation of motion (gravity, viscosity, and drag) is solved for every marker and then exchange of momentum, heat and energy with surrounding vaporair mixture is taken into account. This approach is used in the SOVA code [10] and allows to vary particle sizes within a broad range (from a few m to a few microns). Implicit procedure of velocity update allows a larger time step. The substantial advantage of the model is its three-dimensional geometry, allowing modeling of asymmetric deposits of oblique impact ejecta. Turbulent diffusion is taken into account in a simplified manner [6]. Fragments size-frequency distribution (SFD) may be of crucial importance: while large fragments move ballistically, the smallest ones are passively involved in gas motion. Ejected material is usually transformed into particles under tension. The initial particle velocity is given by the hydrodynamic velocity, but the object's initial position within the cell is randomly defined. The SFD of solid fragments in high velocity impacts has been studied experimentally [2,11], numerically [12,13], and has been derived from the lunar and terrestrial crater observations [14,15]. Various approaches may be used to implement fragment size in a dynamic model: in Grady-Kipp model the average fragment size is defined by strain rate [12]; alternatively, average ejection velocity [16] or maximum shock compression [17] may be used. All methods may be verified through comparison with known data. Volcanic direct blast. Numerical modeling of pyroclastic flows, checked against recent observations and young deposits, may be then a useful instrument for reconstruction of terrestrial craters' ejecta, which are mostly eroded or buried; and for impact ejecta study on other planets

Artemieva, N.

2008-09-01

205

Sex differences in proximal humeral outline shape: elliptical Fourier functions.  

PubMed

A method is presented for the numerical analysis of sex differences in size and shape of the proximal humeral outlines using elliptical Fourier functions (EFFs). A skeletal sample consisting of right and left humeri pairs of 69 individuals, 36 males and 33 females, was used. The proximal superior view in the plane of the proximo-distal axis of each humerus was photographed and then 54 boundary points were located on the two-dimensional outline tracings. These points were digitized and used to compute EFFs with 27 harmonics. From the EFFs, a set of expected points on the proximal humeral outline was generated using the centroid as an origin. Superimposition of the male and female outlines on this centroid provided a detailed picture of the relative sex differences in size and shape with respect to that center. The bounded area of the proximal humeral outline showed statistically significant sex differences. Additionally, statistical results of the amplitudes derived from the "area-standardized" EFFs and visual assessments of the mean outline plots indicated significant sex differences in shape of the proximal humeral outlines. Focusing on localized regional differences, the greater tubercle was located more postero-medially and the lesser tubercle was located more anteriorly in the males compared to the females. Sex determinations from the proximal humeri were also examined with discriminant functions based on the amplitudes, which represent shape characteristics of the outline, and the hounded area. Using a cross-validation method, predictions of the percentages of cases correctly classified with the discriminant functions were ranged from 92.8% to 95.7% for the right and left humeral data. These results suggest that differences in size and shape of the proximal humeral outlines may be better predictors of sex when compared with conventional measurements of the humerus. PMID:10782949

Tanaka, H; Lestrel, P E; Uetake, T; Kato, S; Ohtsuki, F

2000-03-01

206

Degradation and transport of AVP by proximal tubule  

SciTech Connect

High-performance liquid chromatography (HPLC) analysis revealed that (3,4,5-{sup 3}H-Phe{sup 3},Arg{sup 8})vasopressin (({sup 3}H)AVP) was not degraded by isolated renal brush-border membranes or by a cortical lysosomal fraction in vitro; however, in the presence of 1 mM reduced glutathione, ({sup 3}H)AVP was degraded by both preparations. Renal cortical homogenates in vitro and luminal peptidases of proximal tubule in vivo degraded ({sup 3}H)AVP and in both instances yielded phenylalanine, hexapeptide AVP 1-6, heptapeptide AVP 1-7, octapeptide AVP 1-8, and two uncharacterized products X and Y. These data suggest that filtered AVP is reduced in the proximal tubule by a reduced glutathione-dependent transhydrogenase and subsequently cleaved to ({sup 3}H)Phe by tubular aminopeptidases. Following microinfusion of ({sup 3}H)AVP into proximal tubules, 15.7% of the label was absorbed. Five and fifteen minutes after infusion of ({sup 3}H)AVP, sequestration of total label in proximal tubules was 4.5 and 2.1%, respectively, and quantitative electron microscope autoradiography revealed accumulation of grains over apical endocytic vacuoles and lysosomes consistent with endocytic uptake and rapid lysosomal degradation of AVP and/or a large metabolite. Thus, enzymatic cleavage of AVP by luminal and lysosomal peptidases in proximal tubules could involve disulfide bond, C-terminal, and N-terminal loci.

Carone, F.A.; Christensen, E.I.; Flouret, G. (Northwestern Univ. Medical School, Chicago, IL (USA) Univ. of Aarhus (Denmark))

1987-12-01

207

Investigating the influences of season and coastal proximity on the elemental composition of harvested rainwater.  

PubMed

Chemical qualities of harvested rainwater were assessed at two residential study sites on the east coast of Australia in relation to coastal proximity and surrounding land uses over the course of a winter and summer month. Daily rainwater samples were collected from the base outlet and surface levels of stored water for chemical analyses. High resolution inductively coupled plasma-mass spectrometry (ICP-MS) was used to analyse 26 elements in all samples. The summer sampling regime for the industrial coastal Site 1 was dominated by wind gusts originating from the east with a total average elemental load of 25,900+/-17,000 microg/L compared to the significantly lower 10,600+/-3,370 microg/L measured during the winter month, where 84% of wind gust events originated from the west. Data for the inland Site 2, with no proximity to industry, revealed no significant changes in total average loads between the winter (4,870+/-578 microg/L) and summer (4,760+/-2,280 microg/L) months. The most abundant elements found at both sites included Na, K, Mg, and Zn. The rainwater storages at Site 2 fed from a relatively new concrete tiled roof catchment had significantly lower pH and conductivity measurements compared with those at Site 1 with an old galvanised iron roof catchment. It was concluded that seasonal differences in harvested water quality were likely influenced by prevailing wind direction and external influences such as surrounding land uses and proximity to the coast. PMID:20057088

Martin, A R; Coombes, P J; Dunstan, R H

2010-01-01

208

Bringing proximate neighbours into the study of US residential segregation.  

PubMed

The race and ethnicity of neighbours are thought to be critical in shaping household mobility underlying residential segregation. However, studies on this topic have used data at the census-tract level of analysis rather than at the proximate-neighbour level. Using a non-publicly available version of the neighbour-cluster sample within the American Housing Survey, this study incorporates data on the race, ethnicity and socioeconomic characteristics of the proximate neighbours of White, Black and Latino households and examines their impact on household residential satisfaction, out- and in-mobility. Results indicate that proximate-neighbour race and ethnicity matter in influencing endpoints of the mobility process and do not necessarily parallel those at the census-tract level. Implications of these findings are discussed as they relate to the study of residential segregation. PMID:21544258

Friedman, Samantha

2011-01-01

209

Comparison of different proximity potentials for asymmetric colliding nuclei  

NASA Astrophysics Data System (ADS)

Using the different versions of phenomenological proximity potential as well as other parametrizations within the proximity concept, we perform a detailed comparative study of fusion barriers for asymmetric colliding nuclei with asymmetry parameter as high as 0.23. In all, 12 different proximity potentials are robust against the experimental data of 60 reactions. Our detailed study reveals that the surface energy coefficient as well as radius of the colliding nuclei depend significantly on the asymmetry parameter. All models are able to explain the fusion barrier heights within ±10% on the average. The potentials due to Bass 80, AW 95, and Denisov DP explain nicely the fusion cross sections at above- as well as below-barrier energies.

Dutt, Ishwar; Puri, Rajeev K.

2010-06-01

210

A Flexible Proximity Sensor Fully Fabricated by Inkjet Printing  

PubMed Central

A flexible proximity sensor fully fabricated by inkjet printing is proposed in this paper. The flexible proximity sensor is composed of a ZnO layer sandwiched in between a flexible aluminum sheet and a web-shaped top electrode layer. The flexible aluminum sheet serves as the bottom electrode. The material of the top electrode layer is nano silver. Both the ZnO and top electrode layers are deposited by inkjet printing. The fully inkjet printing process possesses the advantages of direct patterning and low-cost. It does not require photolithography and etching processes since the pattern is directly printed on the flexible aluminum sheet. The prototype demonstrates that the presented flexible sensor is sensitive to the human body. It may be applied to proximity sensing or thermal eradiation sensing.

Wang, Chin-Tsan; Huang, Kuo-Yi; Lin, David T. W.; Liao, Wei-Chia; Lin, Hua-Wei; Hu, Yuh-Chung

2010-01-01

211

Comparison of different proximity potentials for asymmetric colliding nuclei  

SciTech Connect

Using the different versions of phenomenological proximity potential as well as other parametrizations within the proximity concept, we perform a detailed comparative study of fusion barriers for asymmetric colliding nuclei with asymmetry parameter as high as 0.23. In all, 12 different proximity potentials are robust against the experimental data of 60 reactions. Our detailed study reveals that the surface energy coefficient as well as radius of the colliding nuclei depend significantly on the asymmetry parameter. All models are able to explain the fusion barrier heights within +-10% on the average. The potentials due to Bass 80, AW 95, and Denisov DP explain nicely the fusion cross sections at above- as well as below-barrier energies.

Dutt, Ishwar; Puri, Rajeev K. [Department of Physics, Panjab University, Chandigarh 160014 (India)

2010-06-15

212

Sealing proximal surfaces with polyurethane tape: three-year evaluation.  

PubMed

The purpose of this investigation was to test the safety and clinical effect of a new material for the treatment of proximal caries. In 50 patients with two proximal initial lesions, one of the lesions was randomly chosen and sealed with a thin polyurethane-dimethacrylate foil using bonding. The other lesion received oral home care and was left as the control. In clinical follow-ups after 6 and 12 months and X-ray evaluation after 2 and 3 years, the sealants showed good retention, marginal adaptation, and color. No relevant significant differences in plaque accumulation or gingival status were found between sealed and control teeth. On the radiographs, almost all sealed and control lesions appeared stable, indicating an arrest of the lesion. In conclusion, sealing initial proximal lesions showed no clinical problems and mostly arrest of caries on bitewing radiographs. PMID:20697755

Alkilzy, Mohammad; Berndt, Christine; Splieth, Christian H

2010-08-10

213

Operative treatment of stress fractures of the proximal second metatarsal.  

PubMed

Proximal stress fractures of the second metatarsal are rare. They have been reported mainly in classical ballet dancers. Non-operative treatment has usually led to good results and rapid return to full activities. We present a series of nine cases with stress fractures of the proximal second metatarsal. The patients were all actively involved in sports. None of them were dancers. In all of these patients non-operative treatment lasting for an average of 13 months had failed. All of the patients were operated on using the same method. In the operation drilling was performed around and through the fracture line. The patients were followed for an average of 38 months. All except one of the patients were able to return to their prior level of activity within 4-6 months. In conclusion if non-operative treatment fails surgery seems to give good results in most patients with a stress fracture of the proximal second metatarsal. PMID:17181771

Sarimo, J; Orava, S; Alanen, J

2006-12-20

214

Bringing Proximate Neighbours into the Study of US Residential Segregation  

PubMed Central

The race and ethnicity of neighbours are thought to be critical in shaping household mobility underlying residential segregation. However, studies on this topic have used data at the census-tract level of analysis rather than at the proximate-neighbour level. Using a non-publicly available version of the neighbour-cluster sample within the American Housing Survey, this study incorporates data on the race, ethnicity and socioeconomic characteristics of the proximate neighbours of White, Black and Latino households and examines their impact on household residential satisfaction, out- and in-mobility. Results indicate that proximate-neighbour race and ethnicity matter in influencing endpoints of the mobility process and do not necessarily parallel those at the census-tract level. Implications of these findings are discussed as they relate to the study of residential segregation.

Friedman, Samantha

2011-01-01

215

Proximal Tibiofibular Joint Ganglion CystsExcision, Recurrence, and Joint Arthrodesis  

Microsoft Academic Search

Objective: Proximal tibiofibular joint proximal tibiofibular joint cysts are rare entities that can cause disability. Excision remains the traditional surgical treatment. Cyst recurrence has been a problem. This study reviews one of the largest series of patients with proximal tibiofibular joint cysts and evaluates the role of a new surgical option, proximal tibiofibular joint fusion.Methods: Thirteen patients were admitted to

Shana Miskovsky; Christopher Kaeding; Lawrence Weis

2004-01-01

216

Numerical analysis of the proximal humeral outline: Bilateral shape differences.  

PubMed

A new method is presented for the numerical analysis of bilateral differences in the size and shape of the proximal humeral outlines using elliptical Fourier functions (EFFs). A skeletal sample of 36 pairs of right and left humeri was used. The proximal superior view in the plane of the proximodistal axis of each humerus was photographed with an 800 mm telephoto lens. The two-dimensional humeral outlines were carefully traced onto acetate sheets and 54 boundary points were located. These points were digitized and used to compute size-standardized EFFs with 27 harmonics. From the EFFs, a set of expected points on the proximal humeral outline was generated using the centroid as an origin. Superimposition of the right and left humeral outlines on this centroid provided a detailed picture of the relative bilateral shape differences with respect to that center. The proximal humeri showed significant bilateral size and shape differences, although the pattern of asymmetry in shape varied with respect to the region on the boundary outline. In particular, one localized aspect, the tubercular region of the proximal humeri showed significant bilateral shape differences. In contrast, the humeral head consistently showed not only a much smaller degree of bilateral shape differences, but also much less variability in size as well as shape. The results suggest that while the overall articular shape changes little with altered mechanical loadings placed on articular surfaces, the changes in the tubercular regions of the proximal humeri may be susceptible to the varying stresses associated with particular physical activities. Am. J. Hum. Biol. 11:343-357, 1999. Copyright 1999 Wiley-Liss, Inc. PMID:11533955

Tanaka, Hideyuki

1999-01-01

217

Cilastatin attenuates cisplatin-induced proximal tubular cell damage.  

PubMed

A major area in cancer therapy is the search for protective strategies against cisplatin-induced nephrotoxicity. We investigated the protective effect of cilastatin on cisplatin-induced injury to renal proximal tubular cells. Cilastatin is a specific inhibitor of renal dehydrodipeptidase I (DHP-I), which prevents hydrolysis of imipenem and its accumulation in the proximal tubule. Primary cultures of proximal cells were treated with cisplatin (1-30 microM) in the presence or absence of cilastatin (200 microg/ml). Apoptosis and mitochondrial injury were assessed by different techniques. Cisplatin uptake and DNA binding were measured by inductively coupled plasma spectrometry. HeLa cells were used to control the effect of cilastatin on the tumoricidal activity of cisplatin. Cisplatin increased cell death, apoptotic-like morphology, caspase activation, and mitochondrial injury in proximal tubular cells in a dose- and time-dependent way. Concomitant treatment with cilastatin reduced cisplatin-induced changes. Cilastatin also reduced the DNA-bound platinum but did not modify cisplatin-dependent up-regulation of death receptors (Fas) or ligands (tumor necrosis factor alpha, Fas ligand). In contrast, cilastatin did not show any effects on cisplatin-treated HeLa cells. Renal DHP-I was virtually absent in HeLa cells. Cilastatin attenuates cisplatin-induced cell death in proximal tubular cells without reducing the cytotoxic activity of cisplatin in tumor cells. Our findings suggest that the affinity of cilastatin for renal dipeptidase makes this effect specific for proximal tubular cells and may be related to a reduction in intracellular drug accumulation. Therefore, cilastatin administration might represent a novel strategy in the prevention of cisplatin-induced acute renal injury. PMID:20435919

Camano, Sonia; Lazaro, Alberto; Moreno-Gordaliza, Estefania; Torres, Ana M; de Lucas, Carmen; Humanes, Blanca; Lazaro, Jose A; Milagros Gomez-Gomez, M; Bosca, Lisardo; Tejedor, Alberto

2010-04-30

218

Proximity effect in a superconductor-metallofullerene-superconductor molecular junction  

NASA Astrophysics Data System (ADS)

We report low-temperature transport measurements through molecules of Gd metallofullerenes between superconducting suspended electrodes. The presence and number of molecules in the 2-nm -wide gap between electrodes was determined by high resolution transmission electron microscopy. We find that a junction containing a single metallofullerene dimer between superconducting electrodes displays signs of proximity-induced superconductivity. In contrast, no proximity effect develops in junctions containing a larger cluster of metallofullerenes. These results can be understood by taking into account multiple Andreev reflections, and the spin states of the Gd atoms.

Kasumov, A. Yu.; Tsukagoshi, K.; Kawamura, M.; Kobayashi, T.; Aoyagi, Y.; Senba, K.; Kodama, T.; Nishikawa, H.; Ikemoto, I.; Kikuchi, K.; Volkov, V. T.; Kasumov, Yu. A.; Deblock, R.; Guéron, S.; Bouchiat, H.

2005-07-01

219

Inverse Proximity Effect in Superconductor-ferromagnet Bilayer Structures  

SciTech Connect

Measurements of the polar Kerr effect using a zero-area-loop Sagnac magnetometer on Pb/Ni and Al/(Co-Pd) proximity-effect bilayers show unambiguous evidence for the 'inverse proximity effect,' in which the ferromagnet (F) induces a finite magnetization in the superconducting (S) layer. To avoid probing the magnetic effects in the ferromagnet, the superconducting layer was prepared much thicker than the light's optical penetration depth. The sign and size of the effect, as well as its temperature dependence agree with recent predictions by Bergeret et al.[1].

Xia, Jing

2010-04-05

220

Isolated scaphoid fracture with anterosuperior dislocation of the proximal fragment.  

PubMed

Isolated fracture of the scaphoid with an associated anterosuperior dislocation of the proximal fragment is an extremely rare injury. We present two cases where open reduction and internal fixation through a palmar and dorsal approach was performed. No instances of non-union, necrosis of the proximal fragment of the scaphoid or scapholunate dissociation were noted during a mean follow-up period of 18 months. Clinical results (active motion, power grip, DASH) following such injury and intervention are presented. The aetiology of this rare injury is discussed. PMID:21795095

Durand, S; MacQuillan, A; Delpit, X

2011-07-05

221

Investigation of proximity effects in electron microscopy and lithography  

SciTech Connect

A fundamental challenge in lithographic and microscopic techniques employing focused electron beams are so-called proximity effects due to unintended electron emission and scattering in the sample. Herein, we apply a method that allows for visualizing electron induced surface modifications on a SiN substrate covered with a thin native oxide layer by means of iron deposits. Conventional wisdom holds that by using thin membranes proximity effects can be effectively reduced. We demonstrate that, contrary to the expectation, these can be indeed larger on a 200 nm SiN-membrane than on the respective bulk substrate due to charging effects.

Walz, M.-M.; Vollnhals, F.; Rietzler, F.; Schirmer, M.; Steinrueck, H.-P.; Marbach, H.

2012-01-30

222

Lateral Casimir Force beyond the Proximity-Force Approximation  

SciTech Connect

We argue that the appropriate variable to study a nontrivial geometry dependence of the Casimir force is the lateral component of the Casimir force, which we evaluate between two corrugated metallic plates outside the validity of the proximity-force approximation. The metallic plates are described by the plasma model, with arbitrary values for the plasma wavelength, the plate separation, and the corrugation period, the corrugation amplitude remaining the smallest length scale. Our analysis shows that in realistic experimental situations the proximity-force approximation overestimates the force by up to 30%.

Rodrigues, Robson B.; Neto, Paulo A. Maia [Instituto de Fisica, UFRJ, CP 68528, Rio de Janeiro, RJ, 21941-972 (Brazil); Lambrecht, Astrid; Reynaud, Serge [Laboratoire Kastler Brossel, CNRS, ENS, Universite Pierre et Marie Curie case 74, Campus Jussieu, F-75252 Paris Cedex 05 (France)

2006-03-17

223

Longitudinal spin Seebeck effect free from the proximity Nernst effect.  

PubMed

This Letter provides evidence for intrinsic longitudinal spin Seebeck effects (LSSEs) that are free from the anomalous Nernst effect (ANE) caused by an extrinsic proximity effect. We report the observation of LSSEs in Au/Y(3)Fe(5)O(12) (YIG) and Pt/Cu/YIG systems, showing that the LSSE appears even when the mechanism of the proximity ANE is clearly removed. In the conventional Pt/YIG structure, furthermore, we separate the LSSE from the ANE by comparing the voltages in different magnetization and temperature-gradient configurations; the ANE contamination was found to be negligibly small even in the Pt/YIG structure. PMID:23432302

Kikkawa, T; Uchida, K; Shiomi, Y; Qiu, Z; Hou, D; Tian, D; Nakayama, H; Jin, X-F; Saitoh, E

2013-02-07

224

Phenytoin induced vitamin d deficiency presenting as proximal muscle weakness  

Microsoft Academic Search

A 6-year-old girl presented with proximal muscle weakness of lower limbs. She was receiving phenytoin for epilepsy for 2 years.\\u000a Serum phenytoin level was within therapeutic range. Serum 25(OH) vitamin D was low (5ng\\/mL) and serum parathyroid hormone\\u000a level was high. After administration of oral vitamin D, muscle weakness improved and vitamin D level increased to 39.11ng\\/mL.\\u000a Proximal muscle weakness

M. M. A. Faridi; Anju Aggarwal

2010-01-01

225

[Proximal femur remodeling after proximal femur varus-derotational osteotomy in treatment of developmental dysplasia of the hip].  

PubMed

The aim of this paper was to assess proximal femur remodelling after proximal femur varus-derotational osteotomy in treatment of developmental dysplasia of the hip up to skeletal maturity. The analysis included 48 osteotomies performed in 33 children between 1st and 10th year of life. The follow-up period was on average 12 years. Supported by statistical evaluation the analysis showed persistent increase of the neck-shaft angle after proximal femur varus-derotational osteotomy, especially in the younger age groups. It also correlated strongly with the amount of varus fixed at the time of operation. On other hand femoral antetorsion corrected during surgery remained unchanged till skeletal maturity. PMID:11481983

Treder, M; Kolarz, K; Omernik, M

2001-01-01

226

Renal proximal tubule function is preserved in Cftrtm2cam?F508 cystic fibrosis mice  

PubMed Central

Changes in proximal tubule function have been reported in cystic fibrosis patients. The aim of this study was to investigate proximal tubule function in the Cftrtm2cam?F508 cystic fibrosis (CF) mouse model. A range of techniques were used including renal clearance studies, in situ microperfusion, RT-PCR and whole-cell patch clamping. Renal Na+ clearance was similar in wild-type (1.4 ± 0.3 ?l min?1, number of animals, N= 12) and CF mice (1.6 ± 0.4 ?l min?1, N= 7) under control conditions. Acute extracellular volume expansion resulted in significant natriuresis in wild-type (7.0 ± 0.8 ?l min?1, N= 8) and CF mice (9.3 ± 1.4 ?l min?1, N= 9); no difference between genotypes was observed. In situ microperfusion revealed that fluid absorptive rate (Jv) was similar under control conditions between wild-type (2.2 ± 0.4 nl mm?1 min?1, n= 10) and CF mice (1.9 ± 0.3 nl mm?1 min?1, n= 11). Addition of a forskolin-dibutyryl cAMP (db-cAMP) cocktail to the perfusate caused no significant change in Jv in either wild-type (2.6 ± 0.7 nl mm?1 min?1, n= 10) or Cftrtm2cam?F508 mice (2.0 ± 0.5 nl mm?1 min?1, n= 10). CFTR expression was confirmed in samples of outer cortex using RT-PCR. However, no evidence for functional CFTR was obtained when outer cortical cells were stimulated with protein kinase A or forskolin-db-cAMP using whole-cell patch clamping. In conclusion, no functional deficit in proximal tubule function was found in Cftrtm2cam?F508 mice. This may be a consequence of a lack of whole-cell cAMP-dependent Cl? conductance in mouse proximal tubule cells.

Kibble, J D; Balloch, K J D; Neal, A M; Hill, C; White, S; Robson, L; Green, R; Taylor, C J

2001-01-01

227

Ion transport in proximal colon of the rat. Sodium depletion stimulates neutral sodium chloride absorption.  

PubMed Central

The model of sodium and chloride transport proposed for the colon is based on studies performed in the distal segment and tacitly assumes that ion transport is similar throughout the colon. In rat distal colon, neutral sodium-chloride absorption accounts for the major fraction of overall sodium absorption and aldosterone stimulates electrogenic, amiloride-sensitive sodium absorption. Since we have demonstrated qualitative differences in potassium transport in proximal and distal segments of rat colon, unidirectional 22Na and 36Cl fluxes were performed under short-circuit conditions across isolated proximal colon of control and sodium-depleted rats with secondary hyperaldosteronism. In the control group, net sodium absorption (JNanet) (7.4 +/- 0.5 mu eq/h . cm2) was greater than Isc (1.4 +/- 0.1 mu eq/h . cm2), and JClnet was 0 in Ringer solution. Residual flux (JR) was -5.2 +/- 0.5 mu eq/h . cm2 consistent with hydrogen ion secretion suggesting that neutral sodium absorption may represent sodium-hydrogen exchange. 1 mM mucosal amiloride, which inhibits sodium-hydrogen exchange in other epithelia, produced comparable decreases in JNanet and JR (4.1 +/- 0.6 and 3.2 +/- 0.6 mu eq/h . cm2, respectively) without a parallel fall in Isc. Sodium depletion stimulated JNanet, JClnet, and Isc by 7.0 +/- 1.4, 6.3 +/- 1.9, and 0.8 +/- 0.2 mu eq/h . cm2, respectively, and 1 mM amiloride markedly inhibited JNanet and JClnet by 6.0 +/- 1.1 and 4.0 +/- 1.6 mu eq/h . cm2, respectively, with only a minimal reduction in Isc. Conclusions: the predominant neutral sodium-absorptive mechanism in proximal colon is sodium-hydrogen exchange. Sodium depletion stimulates electroneutral chloride-dependent sodium absorption (most likely as a result of increasing sodium-hydrogen and chloride-bicarbonate exchanges), not electrogenic chloride-independent sodium transport. The model of ion transport in the proximal colon is distinct from that of the distal colon.

Foster, E S; Budinger, M E; Hayslett, J P; Binder, H J

1986-01-01

228

Western Blotting via Proximity Ligation for High Performance Protein Analysis*  

PubMed Central

Western blotting is a powerful and widely used method, but limitations in detection sensitivity and specificity, and dependence upon high quality antibodies to detect targeted proteins, are hurdles to overcome. The in situ proximity ligation assay, based on dual antibody recognition and powerful localized signal amplification, offers increased detection sensitivity and specificity, along with an ability to identify complex targets such as phosphorylated or interacting proteins. Here we have applied the in situ proximity ligation assay mechanism in Western blotting. This combination allowed the use of isothermal rolling circle amplification of DNA molecules formed in target-specific ligation reaction, for 16-fold or greater increase in detection sensitivity. The increased specificity because of dual antibody recognition ensured highly selective assays, detecting the specific band when combinations of two cross-reactive antitubulin antibodies were used (i.e. both producing distinct nonspecific bands in traditional Western blotting). We also demonstrated detection of phosphorylated platelet-derived growth factor receptor ? by proximity ligation with one antibody directed against the receptor and another directed against the phosphorylated tyrosine residue. This avoided the need for stripping and re-probing the membrane or aligning two separate traditional blots. We demonstrate that the high-performance in situ proximity ligation-based Western blotting described herein is compatible with detection via enhanced chemiluminescence and fluorescence detection systems, and can thus be readily employed in any laboratory.

Liu, Yanling; Gu, Jijuan; Hagner-McWhirter, ?sa; Sathiyanarayanan, Poojahrau; Gullberg, Mats; Soderberg, Ola; Johansson, Johan; Hammond, Maria; Ivansson, Daniel; Landegren, Ulf

2011-01-01

229

Geographic Proximity, Trade and International Conflict\\/Cooperation  

Microsoft Academic Search

This paper examines the interactive effect of distance and trade on international conflict and cooperation. The effect of geographic distance depends on trade, while the effect of trade varies with geographic distance. Trade reduces conflict to a greater extent when dyads are geographically close, but has a greater effect on cooperation when countries are more distant. Geographic proximity increases conflict

John Robst; Solomon W Polachek; Yuan-Ching Chang

2006-01-01

230

Geographic Proximity, Trade, and International Conflict\\/Cooperation  

Microsoft Academic Search

This article examines the interactive effect of distance and trade on international conflict and cooperation. The effect of geographic distance depends on trade, while the effect of trade varies with geographic distance. Trade reduces conflict to a greater extent when dyads are geographically close, but has a greater effect on cooperation when countries are more distant. Geographic proximity increases conflict

John Robst; Solomon Polachek; Yuan-Ching Chang

2007-01-01

231

Evolution and Proximate Expression of Human Paternal Investment  

Microsoft Academic Search

In more than 95% of mammalian species, males provide little direct investment in the well-being of their offspring. Humans are one notable exception to this pattern and, to date, the factors that contributed to the evolution and the proximate expression of human paternal care are unexplained (T. H. Clutton-Brock, 1989). The nature, extent, and influence of human paternal investment on

David C. Geary

2000-01-01

232

The impact of grandparental proximity on maternal childcare in China  

Microsoft Academic Search

This paper investigates the impact of the proximity of grandparents' residence on mother's childcare involvement in contemporary China. Drawing on data from the 1991 China Health and Nutrition Survey, we find that the presence of grandparents in the household significantly reduces a mother's involvement in childcare. Nearby residence of grandparents also decreases mothers' childcare involvement, but only in the case

Feinian Chen; Susan E. Short; Barbara Entwisle

2000-01-01

233

Referrals for pediatric weight management: the importance of proximity  

Microsoft Academic Search

BACKGROUND: Limited access to weight management care can have a negative impact on the health and well-being of obese children and youth. Our objectives were to describe the characteristics of clients referred to a pediatric weight management centre and explore potential differences according to proximity. METHODS: All demographic and anthropometric data were abstracted from standardized, one-page referral forms, which were

Kathryn A Ambler; Douglas WJ Hagedorn; Geoff DC Ball

2010-01-01

234

A Procedure to Estimate Proximate Analysis of Mixed Organic Wastes  

Microsoft Academic Search

In waste materials, proximate analysis measuring the total concentration of carbohydrate, protein, and lipid contents from solid wastes is challenging, as a result of the heterogeneous and solid nature of wastes. This paper presents a new procedure that was developed to estimate such complex chemical composition of the waste using conventional practical measurements, such as chemical oxygen demand (COD) and

U. Zaher; P. Buffiere; J-P Steyer; S. Chen

235

Proximal tibial physis fracture and popliteal artery injury.  

PubMed

A case of fracture about the proximal tibial physis with associated popliteal artery injury is presented. These fractures are not common, but their complications can be disastrous. The radiologist should draw attention to the possibility of vascular injury when these fractures are recognized. PMID:6691091

Rivero, H; Bolden, R; Young, L W

1984-02-01

236

Postpartum osteoporosis associated with proximal tibial stress fracture  

Microsoft Academic Search

A 33-year-old woman presented with acute nonspecific knee pain, 6 months postpartum. MR imaging, computed tomography and radiography were performed and a proximal tibia plateau insufficiency fracture was detected. Bone densitometry demonstrated mild postpartum osteoporosis. To our knowledge these findings have not been described in this location and in this clinical setting. The etiology of the atraumatic fracture of the tibia

I. A. Clemetson; A. Popp; K. Lippuner; F. Ballmer; S. E. Anderson

2004-01-01

237

Scaffolding Emergent Writing in the Zone of Proximal Development  

Microsoft Academic Search

Scaffolded Writing is an innovative method of supporting emergent writing based on Vygotsky's theory of learning and development. This article discusses the theoretical notions underlying the method: the zone of proximal develop - ment, scaffolding, materialization, and private speech. A description of Scaffolded Writing is given along with classroom examples. A case study of 34 at-risk kindergarten children is reported

Elena Bodrova; Deborah J. Leong

1998-01-01

238

Institutional Creativity: The Relational Zone of Proximal Development  

Microsoft Academic Search

In this article I argue that creative acts cannot be confined to the individual. Creativity can be seen as a meeting between an individual and a wider activity system. This argument is related to the claim that a zone of proximal development (ZPD), the concept connected to the culturalhistorical psychologist Lev Vygotsky, is both an internal and an external relation

Cathrine Hasse

2001-01-01

239

The Transference and the Zone of Proximal Development  

Microsoft Academic Search

The Zone of Proximal Development (ZPD) is discussed, a construct that, when introduced into psychoanalysis, advances understanding of the key clinical relationship between the intrapsychic and the interpersonal. Strands from several psychoanalytic formulations are brought together and forged into a coherent construct, which is then contrasted with the transference. It is shown how the ZPD provides the transference with its

Arnold Wilson; Lissa Weinstein

1996-01-01

240

Understanding the Zone of Proximal Development in Adult Literacy Learning  

Microsoft Academic Search

The purpose of this qualitative case study was to investigate how adult learners in formal literacy classroom programs improve their reading and writing skills through scaffolding and guided participation. An early organizing framework emerged that depicts four major types of collaborative practices used among peers as they move towards the Zone of Proximal Development.

Maurice Taylor; Christine Pinsent-Johnson

241

Group Problem Solving as a Zone of Proximal Development activity  

Microsoft Academic Search

Vygotsky described learning as a process, intertwined with development, which is strongly influenced by social interactions with others that are at differing developmental stages.i These interactions create a Zone of Proximal Development for each member of the interaction. Vygotsky's notion of social constructivism is not only a theory of learning, but also of development. While teaching introductory physics in an

Eric Brewe

2006-01-01

242

Influence of Distal and Proximal Cognitive Processes on Word Reading  

ERIC Educational Resources Information Center

The objectives of the present study were twofold: (a) to explore the interrelationship among distal, proximal cognitive skills, and word reading; and (b) to identify those cognitive processes that predict phonological awareness and rapid naming. Seventy First-Nation Canadian children attending grades 3 and 4 were examined on phonological…

Das, J. P.; Georgiou, George; Janzen, Troy

2008-01-01

243

Proximity of Clothing to Self: Evolution of a Concept  

Microsoft Academic Search

Proximity of clothing to self is a multifaceted concept conceived as the psychological closeness of clothing to self and indicated by the extent to which clothing is (1) perceived as one with the self or as a component of the self, (2) recognized as an aspect of appearance by which the self is established and validated, (3) recognized as a

M. Suzanne Sontag; Jean Davis Schlater

1982-01-01

244

Adapting of String Indexing Systems for Retrieval Using Proximity Operators.  

ERIC Educational Resources Information Center

Presents a methodology for extending string indexing from index display production to the provision of descriptor phrases for term proximity searching. Objectives of the extension are discussed, and an illustration of the use of an existing string indexing system for this purpose is given. (14 references) (CLB)

Craven, Timothy C.

1988-01-01

245

Efficiently Computing Weighted Proximity Relationships in Spatial Databases  

Microsoft Academic Search

Spatial data mining recently emerges from a number of real applications, such as real-estate marketing, urban planning, weather forecasting, medical image analysis, road traffic accident analysis, etc. It demands for efficient solutions for many new, expensive, and complicated problems. In this paper, we investigate the problem of evaluating the top k distinguished "features" for a "cluster" based on weighted proximity

Xuemin Lin; Xiaomei Zhou; Chengfei Liu; Xiaofang Zhou

2001-01-01

246

The physiology of the female orgasm as a proximate mechanism  

Microsoft Academic Search

The dynamics of female orgasms were investigated and proposed as a possible proximate mechanism implicated in female mating strategies. Specifically, the role of female orgasm in motivating women to engage in sexual relations while refraining from engaging indiscriminately in one-night stands (ONS) was explored. A total of 202 Western women of reproductive age were surveyed about their sexual behaviour, practices,

Lara Eschler

2004-01-01

247

Detection of Individual Microbial Pathogens by Proximity Ligation  

Microsoft Academic Search

Background: Nucleic acid amplification allows the de- tection of single infectious agents. Protein-based assays, although they provide information on ongoing infec- tions, have substantially less detection sensitivity. Methods: We used proximity ligation reactions to detect proteins on bacteria and virus particles via nucleic acid amplification. Antibodies recognizing viral or bacterial surface proteins were equipped with DNA strands that could be

Sigrun M. Gustafsdottir; Ann Nordengrahn; Simon Fredriksson; Per Wallgren; Esteban Rivera; Edith Schallmeiner; Malik Merza; Ulf Landegren

248

Influence of Distal and Proximal Cognitive Processes on Word Reading  

Microsoft Academic Search

The objectives of the present study were twofold: (a) to explore the interrelationship among distal, proximal cognitive skills, and word reading; and (b) to identify those cognitive processes that predict phonological awareness and rapid naming. Seventy First-Nation Canadian children attending grades 3 and 4 were examined on phonological awareness, rapid naming, Word Identification, Word Attack, and the cognitive processing measures

J. P. Das; George Georgiou; Troy Janzen

2008-01-01

249

The Grammaticalization of the Proximative in Tok Pisin.  

ERIC Educational Resources Information Center

Discusses grammaticalization of "laik" in Tok Pisin, meaning "want/like/desire" (from English "like") and "klostu," meaning "near" (from English "close to") as markers of proximative. Shows although "klostu" was more generally a feature of Pacific Pidgin English and began to grammaticalize in mid-19th century, is now in competition with "laik," a…

Romaine, Suzanne

1999-01-01

250

Spaces of Innovation: Learning, Proximity and the Ecological Turn  

Microsoft Academic Search

Healy A. and Morgan K. Spaces of innovation: learning, proximity and the ecological turn, Regional Studies. Contrary to the fashionable ‘death of distance’ thesis, the socio-spatial context for innovation remains as important as ever for firms, networks and the public institutions that tend to be neglected in orthodox narratives of learning. This article explores the changing socio-spatial dynamics of innovation

Adrian Healy; Kevin Morgan

2012-01-01

251

The Grammaticalization of the Proximative in Tok Pisin.  

ERIC Educational Resources Information Center

|Discusses grammaticalization of "laik" in Tok Pisin, meaning "want/like/desire" (from English "like") and "klostu," meaning "near" (from English "close to") as markers of proximative. Shows although "klostu" was more generally a feature of Pacific Pidgin English and began to grammaticalize in mid-19th century, is now in competition with "laik," a…

Romaine, Suzanne

1999-01-01

252

Autonomous Distributed Control of Simultaneous Multiple Spacecraft Proximity Maneuvers  

Microsoft Academic Search

An autonomous distributed control algorithm for multiple spacecraft performing simultaneous close proximity maneuvers has been developed. Examples of these maneuvers include automated on-orbit inspection, assembly, or servicing. The proposed control algorithm combines the control effort efficiency of the Linear Quadratic Regulator (LQR) and the robust collision avoidance capability of the Artificial Potential Function (APF) method. The LQR control effort serves

Shawn Baxter McCamish; Marcello Romano; Xiaoping Yun

2010-01-01

253

PROXIMITY OF LOUISIANA SANITARY LANDFILLS TO WETLANDS AND DEEPWATER HABITATS  

EPA Science Inventory

Sanitary landfills can cause considerable harm to sensitive ecosystems if they are not properly located, designed, and managed. The proximity of Louisiana sanitary landfills to wetlands and deepwater habitats was determined by drawing three concentric 1/4 mile, 1/2 mile, and 1 mi...

254

Energy efficient transmission scheduling over Mars proximity links  

Microsoft Academic Search

We consider the scheduling of transmissions from an energy limited Mars lander to a Mars orbiter. Typically, the channel quality of the Mars proximity links is time-varying due to orbital dynamics, multi-path effects and the antenna positioning on the lander. Since the channel state determines the throughput obtained per unit of energy transmitted, it is desirable to select when, and

Alessandro Tarello; Jay L. Gao; Eytan H. Modiano

2006-01-01

255

Interlanguage Pragmatics in the Zone of Proximal Development  

ERIC Educational Resources Information Center

|Vygotsky's zone of proximal development (ZPD) has been fruitfully applied in L2 research that examines second and foreign language learning. This paper considers the applicability of the ZPD to interlanguage pragmatics instruction and research. First, the ZPD is defined [Vygotsky, L.S., 1978. Mind in Society: The Development of Higher…

Ohta, Amy Snyder

2005-01-01

256

Atypical form of X-linked proximal pseudohypertrophic muscular dystrophy  

Microsoft Academic Search

A series of 95 families, consisting of 317 patients with severe and mild X-linked proximal pseudohypertrophic muscular dystrophy (MD), was analysed by the use of two different and rigid clinical criteria based on the age when the patient became chairbound. Using these criteria the families from Erfurt and Warsaw could be clearly separated into classical Duchenne (DMD) and classical Becker

A. W. J. Spiegler; I. Hausmanowa-Petrusewicz; J. Borkowska; F. H. Herrmann

1987-01-01

257

Changing Features of Proximal Vein Thrombosis Over Time  

Microsoft Academic Search

Recently, the sensitivity of impedance plethysmography (IPG) for the diagnosis of acute deep-vein thrombosis (DVT) in symptomatic outpatients has been questioned. In order to verify whether a change in the venographic pattern of DVT has occurred over years, accounting for the decreased sensitivity of IPG, the authors compared two series of consecutive venograms demonstrating proximal DVT, performed between 1984-1988 (166

Alberto Cogo; Paolo Prandoni; Sabina Villalta; Paola Polistena; Enrico Bernardi; Paolo Simioni; Mario Vigo; Lino Benedetti; Antonio Girolami

1994-01-01

258

A new microlens array fabrication method using UV proximity printing  

Microsoft Academic Search

This paper presents a new microlens array fabrication method that controls the printing gap in the UV lithography process. This method can precisely control the microlens array geometric profile array in the fabrication process without thermal reflow. The proximity printing bends the UV light away from the aperture edges and produces a certain exposure in the photoresist outside the aperture

Lin Che-Ping; Yang Hsiharng; Chao Ching-Kong

2003-01-01

259

On the Surprising Salience of Curvature in Grouping by Proximity  

ERIC Educational Resources Information Center

|The authors conducted 3 experiments to explore the roles of curvature, density, and relative proximity in the perceptual organization of ambiguous dot patterns. To this end, they developed a new family of regular dot patterns that tend to be perceptually grouped into parallel contours, dot-sampled structured grids (DSGs). DSGs are similar to the…

Strother, Lars; Kubovy, Michael

2006-01-01

260

Peripheral Nerve Injuries of the Proximal Lower Limb in Athletes  

Microsoft Academic Search

\\u000a Sports injuries that affect the peripheral nerves of the proximal lower limb (above the knee) are relatively uncommon. Injuries\\u000a involving the lumbosacral plexus occur more often than peripheral nerve injuries. Of peripheral nerve injuries in athletes,\\u000a sciatic neuropathy is the most common.1 In this chapter we cover injuries to the following nerves.

Marla S. Kaufman; Mark E. Domroese

261

Determination of chloride and bicarbonate permeabilities in proximal convoluted tubules.  

PubMed

In late proximal tubules volume reabsorption linked to passive ion flows relies on the existence of differing permeability coefficients to Cl- and HCO3(-) (PCl greater than PHCO3). We measured these permeability coefficients in late segments of rabbit superficial (SFPCT) and juxtamedullary (JMPCT) proximal convoluted tubules perfused in vitro. PHCO3 and P36Cl were determined in tubules bathed in rabbit serum and perfused with a serum ultrafiltrated titrated with H2SO4 to [HCO3(-)] of 4 mM. Active transport, transepithelial voltage, and HCO3(-) reabsorption were inhibited by cooling (21 degrees C) and 10(-4) M acetazolamide. P36Cl and PHCO3 were calculated from 36Cl disappearance from and total CO2 addition to the perfusate. P36Cl in SFPCT was twice that in JMPCT but PHCO3 was the same in both segments. P36Cl exceeded PHCO3 only in SFPCT. To exclude exchange diffusion from contributing to P36Cl, additional tubules were perfused with ultrafiltrate titrated with HCl.P36Cl and simultaneously measured PCl (lumen-to-bath net chemical Cl- flux) were identical. We conclude: 1) SFPCT and JMPCT are heterogeneous with respect to Cl- permeability; 2) relative Cl--to-HCO3(-) permeabilities predict that anion gradients present in late portions of proximal tubules would support more volume reabsorption linked to passive ion flows in SF than in JMPCT; 3) no significant Cl- exchange diffusion exists in proximal tubules. PMID:7315963

Holmberg, C; Kokko, J P; Jacobson, H R

1981-10-01

262

The impact of DHT routing geometry on resilience and proximity  

Microsoft Academic Search

The various proposed DHT routing algorithms embody several different underlying routing geometries. These geometries include hypercubes, rings, tree-like structures, and butterfly networks. In this paper we focus on how these basic geometric approaches affect the resilience and proximity properties of DHTs. One factor that distinguishes these geometries is the degree of flexibility they provide in the selection of neighbors and

K. Gummadi; Ramakrishna Gummadi; Steven D. Gribble; Sylvia Ratnasamy; Scott Shenker; Ion Stoica

2003-01-01

263

Treatment strategies for proximal femur fractures in osteoporotic patients  

Microsoft Academic Search

Fractures of the proximal end of the femur, together with vertebral fractures, are greatly exacerbated by osteoporosis and can be regarded as the most typical and most serious complications of this disease. The demand for prompt mobilisation with full loading of the affected limb, combined with a desire for the gentlest of treatments, becomes increasingly difficult to meet in ageing

Felix Bonnaire; Henry Zenker; Christoph Lill; Andreas T. Weber; Berend Linke

2005-01-01

264

Hierarchical optical proximity correction on contact hole layers  

Microsoft Academic Search

As the size of contact holes shrinks below 0.2 ?m, optical proximity correction (OPC) on contact hole layers becomes essential. When correcting contact holes, 1-dimensional correction is not applicable, and 2-dimensional correction is required, which needs much more intensive computation. To reduce computation, it is very effective to take advantage of the hierarchy of the input data. In order to

K. Yamamoto; S. Kobayashi; T. Uno; T. Kotani; S. Tanaka; S. Inoue; S. Watanabe; H. Higurashi

2000-01-01

265

Proximity and specificity of planning: A position paper  

Microsoft Academic Search

The results of a recent set of studies have generated some confusion about the parameters of planning. Several findings seem to suggest that relatively proximal and specific planning improves self-regulation, whereas other research seems to favor more distal and less specific planning. The relevant concepts are defined and the literature is reviewed in an attempt to begin resolving these apparent

Daniel S. Kirschenbaum

1985-01-01

266

Does spatial proximity drive norovirus transmission during outbreaks in hospitals?  

PubMed Central

Objective To assess the role of spatial proximity, defined as patients sharing bays, in the spread of norovirus during outbreaks in hospitals. Design Enhanced surveillance of norovirus outbreaks between November 2009 and November 2011. Methods Data were gathered during 149 outbreaks of norovirus in hospital wards from five hospitals in two major cities in England serving a population of two million. We used the time between the first two cases of each outbreak to estimate the serial interval for norovirus in this setting. This distribution and dates of illness onset were used to calculate epidemic trees for each outbreak. We then used a permutation test to assess whether proximity, for all outbreaks, was more extreme than would be expected by chance under the null hypothesis that proximity was not associated with transmission risk. Results 65 outbreaks contained complete data on both onset dates and ward position. We estimated the serial interval to be 1.86?days (95% CI 1.6 to 2.2?days), and with this value found strong evidence to reject the null hypothesis that proximity was not significant (p<0.001). Sensitivity analysis using different values of the serial interval showed that there was evidence to reject the null hypothesis provided the assumed serial interval was less than 2.5?days. Conclusions Our results provide evidence that patients occupying the same bay as patients with symptomatic norovirus infection are at an increased risk of becoming infected by these patients compared with patients elsewhere in the same ward.

Harris, John P; Lopman, Ben A; Cooper, Ben S; O'Brien, Sarah J

2013-01-01

267

Voltage collapse proximity indicators for radial distribution networks  

Microsoft Academic Search

Based on the single-line equivalent system of a radial distribution network, two simple methods to evaluate two efficient voltage collapse proximity indicators are presented and discussed. The two methods differ on the determination of the parameters which define the equivalent system from which the indicators are derived. Both methods can be conveniently used jointly for on-line applications to assess the

Antonino Augugliaro; Luigi Dusonchet; Stefano Mangione

2007-01-01

268

Proximate nutritive value changes during decomposition of salt marsh plants  

Microsoft Academic Search

Recognition of salt marsh plant detritus as a nutritious source of food for estuarine consumers prompted investigation of in situ decomposition and proximate nutritive values of three plants and their detritus namely: Spartina cynosuroides and Distichlis spicata (Gramineae) and Scirpus americanus (Cyperaceae) growing abundantly in Mississippi tidal marshes. During decomposition to particulate detritus, these plants retain 60–70% organic content and

Armando A. Cruz

1975-01-01

269

Metabolism of Cisplatin to a Nephrotoxin in Proximal Tubule Cells  

Microsoft Academic Search

Cisplatin, a commonly used chemotherapeutic agent, is nephrotoxic. The mechanism by which cisplatin selectively kills the proximal tubule cells was heretofore unknown. Recent studies in mice and rats have shown that the nephrotoxicity of cisplatin can be blocked by acivicin or (aminooxy)acetic acid, the same enzyme inhibitors that block the metabolic activation of a series of nephrotoxic halogenated alkenes. In

DANYELLE M. TOWNSEND; MEI DENG; LEI ZHANG; MAIA G. LAPUS; MARIE H. HANIGAN

2003-01-01

270

Variable Reluctance Proximity Sensors for Cryogenic Valve Position Indication.  

National Technical Information Service (NTIS)

A test was conducted to determine the performance of a variable reluctance proximity sensor system when installed in a space shuttle external tank vent/relief valve. The sensors were used as position indicators. The valve and sensors were cycled through a...

R. A. Cloyd

1982-01-01

271

Proximal dup(10q): Case report and literature review  

SciTech Connect

We report a case of a proximal dir dup(10q) in a female with multiple congenital anomalies. During infancy she was noted to gave growth retardation, microcephaly, microphthalmia, coloboma, a long, beaked nose, posteriorly rotated ears with simple helices, full bowed lips, widely-spaced nipples, broad first toes, hypermobile and proximally placed thumbs, a heart murmur, PDA, and coarctation of the aorta. Additional findings at age 13 included a full columella, short philtrum, thin limbs, bilateral blindness, and mental retardation, as well as continued growth retardation. Her medical history included precocious puberty at age 8 and a diagnosis of hyperactivity. Using FISH with multiple probes combined with GTG-banding, the aberrant chromosome was determined to be a dir dup(10)(q21{r_arrow}q22). Parental chromosomes were normal and the family history was unremarkable. The parental origin of the dir dup(10) is being assessed using DNA markers. Five similar cases of proximal dup(10q) have been reported previously. Consistent characteristics include low birth weight, developmental and psychomotor delay, growth retardation, and microcephaly. Also found in most cases were short prominent philtrum, bowed mouth, PDA, thin limbs, coloboma, micropthalmia, deep set eyes, and other ocular anomalies. Our case is unique in that she has a long, beaked nose, precocious puberty, and hyperactivity. Future studies such as this, using molecular cytogenetic techniques to better define the chromatin involved in proximal dup(10q), may lead to its recognition as a distinct clinical phenotype.

Barritt, J.A.; Teague, K.E.; Bodurtha, J.N. [Virginia Commonwealth Univ., Richmond, VA (United States)] [and others

1994-09-01

272

Proximal-Goal Facilitation of Children's Achievement and Interest.  

ERIC Educational Resources Information Center

|This experiment was designed to (1) test the effectiveness of proximal goals in promoting performance, developing self-efficacy, and fostering interest in activities, and (2) investigate the relationship between self-efficacy and interest. The focus of the study was children's mastery of arithmetic operations in which they had displayed low…

Schunk, Dale H.

273

Geographic proximity and price discovery: Evidence from NASDAQ  

Microsoft Academic Search

We use the NASDAQ market making context to study the role of geographic proximity in the price discovery of a firm's stock. We show that market makers closer to the firm's headquarters spend more time at the inside bid and ask quotes, initiate larger changes in the quotes, and account for greater information share when compared to non-local market makers.

Amber Anand; Vladimir A. Gatchev; Leonardo Madureira; Christo A. Pirinsky; Shane Underwood

2011-01-01

274

Geographical proximity and supplying relationships in modular production  

Microsoft Academic Search

The geography of the automotive industry has changed in recent years. This article focuses on the changes that are associated with 'modular production', whose diffusion has reinforced the need for proximity between auto-makers and parts-makers. The new geographical configurations that have cropped up, especially in the field of assembly operations, are based on spatial contiguity. On one hand, this spatial

Vincent Frigant; Yannick Lung

2002-01-01

275

Structures and Methods for Proximity Communication Using Bridge Chips.  

National Technical Information Service (NTIS)

One embodiment of the present invention provides a system that facilitates proximity communication using a bridge chip. This system includes a base chip with an active face, upon which active circuitry and signal pads reside, and a back face opposite the ...

A. R. Zingher A. V. Krishnamoorthy B. M. Guenin N. I. Nettleton R. Ho

2005-01-01

276

Precision relative navigation solution for autonomous operations in close proximity  

Microsoft Academic Search

The ability to provide highly accurate and reliable relative navigation information in real time is a key enabling technology for autonomous operations between moving platforms in close proximity. Northrop Grummanpsilas Navigation Systems Sivision (NSD) has developed an innovative approach to relative navigation that fuses Global Positioning System (GPS) pseudorange and carrier phase measurements with Inertial Navigation System (INS) data and

K. Liu; C. Moore; R. Buchler; P. Bruner; A. Fax; J. L. Hinchman; B. T. Nguyen; D. E. Nelson; F. Ventrone; B. R. Thorward

2008-01-01

277

Proximity effect of UWB antenna on human body  

Microsoft Academic Search

In this paper, two types of UWB antennas, with and without band-notched characteristics were placed in proximity of the human body. The effects of the human body on the impedance and gain are investigated. The transmission performance is also analyzed for the different body orientations. Generally, the impedance is sensitive to the presence of the body, although the band-notched characteristic

Terence S. P. See; Z. N. Chen; X. M. Qing

2009-01-01

278

Rupture of a Large Vertebral Artery Aneurysm Following Proximal Occlusion  

PubMed Central

Summary Proximal occlusion of the vertebral artery is regarded as a safe and effective method of treating aneurysms of the vertebral artery or the vertebrobasilar junction unsuitable for treatment by neck clipping. Complications known to develop after this procedure include ischemic lesions of the perforators and other areas. There are only a limited number of reports on early rupture of aneurysm following proximal occlusion of the vertebral artery for the treatment of unruptured aneurysm. We recently encountered a case of large aneurysm of the vertebral artery identified after detection of brainstem compression. This patient underwent proximal occlusion of the vertebral artery with a coil and developed a fatal rupture of the aneurysm ten days after proximal occlusion. The patient was a 72-year-old woman who had complained of dysphagia and unsteadiness for several years. An approximately 20 mm diameter aneurysm was detected in her left vertebral artery. She underwent endovascular treatment, that is, her left vertebral artery was occluded with coils at a point proximal to the aneurysm. Her initial post-procedure course was uneventful. However, she suddenly developed right-side hemiparesis nine days after procedure. At that time, CT scan suggested sudden thrombosis of the aneurysm. Right vertebral angiography revealed a small part of the aneurysm. She was treated conservatively. Ten days after the procedure, she suffered massive subarachnoid haemorrhage. Both the present case and past reports suggest that proximal occlusion of the vertebral artery is effective in treating relatively large aneurysms unsuitable for treatment by neck clipping or trapping. However, when the bifurcation of the posterior inferior cerebellar artery (PICA) is distal to the occluded point in cases where the PICA bifurcates from the aneurysm or the neck region, blood supply to the aneurysm may persist because anterograde blood flow to the PICA may be preserved. Therefore, clinicians must consider the possibility of aneurysm rupture after proximal occlusion in the following cases: 1) when the aneurysm is large or giant, but non-thrombosed; 2) when thrombosis occurs soon after the procedure; 3) when postoperative angiography shows partial filling of the aneurysm with contrast agent through the contralateral vertebral artery of basilar artery or the cervical muscle branches.

Iwabuchi, S.; Yokouchi, T.; Kimura, H.; Ueda, M.; Samejima, H.

2005-01-01

279

A procedure to estimate proximate analysis of mixed organic wastes.  

PubMed

In waste materials, proximate analysis measuring the total concentration of carbohydrate, protein, and lipid contents from solid wastes is challenging, as a result of the heterogeneous and solid nature of wastes. This paper presents a new procedure that was developed to estimate such complex chemical composition of the waste using conventional practical measurements, such as chemical oxygen demand (COD) and total organic carbon. The procedure is based on mass balance of macronutrient elements (carbon, hydrogen, nitrogen, oxygen, and phosphorus [CHNOP]) (i.e., elemental continuity), in addition to the balance of COD and charge intensity that are applied in mathematical modeling of biological processes. Knowing the composition of such a complex substrate is crucial to study solid waste anaerobic degradation. The procedure was formulated to generate the detailed input required for the International Water Association (London, United Kingdom) Anaerobic Digestion Model number 1 (IWA-ADM1). The complex particulate composition estimated by the procedure was validated with several types of food wastes and animal manures. To make proximate analysis feasible for validation, the wastes were classified into 19 types to allow accurate extraction and proximate analysis. The estimated carbohydrates, proteins, lipids, and inerts concentrations were highly correlated to the proximate analysis; correlation coefficients were 0.94, 0.88, 0.99, and 0.96, respectively. For most of the wastes, carbohydrate was the highest fraction and was estimated accurately by the procedure over an extended range with high linearity. For wastes that are rich in protein and fiber, the procedure was even more consistent compared with the proximate analysis. The new procedure can be used for waste characterization in solid waste treatment design and optimization. PMID:19445330

Zaher, U; Buffiere, P; Steyer, J P; Chen, S

2009-04-01

280

Anatomic mapping for surgical reconstruction of the proximal tibiofibular ligaments.  

PubMed

Injury to the proximal tibiofibular joint is uncommon. Previous studies regarding the anatomy of this region have predominantly focused on joint orientation. As radiographic technology has advanced, later studies have attempted to evaluate the capsular anatomy. However, no reports specifically map the ligaments to this joint. The objectives of the current study were to define specific ligamentous structures that provide stability to the proximal tibiofibular joint, describe easily identifiable and reproducible surgical landmarks to aid in surgical reconstruction, and add to the understanding of the posterolateral structures of the knee previously described by other authors. The proximal tibiofibular joint ligaments were identified in 10 fresh-frozen cadaveric specimens. Average ligament length, width, and thickness and area of the footprints of the tibial and fibular attachments were measured. Distances from the ligament footprints to known anatomic landmarks (eg, Gerdy's tubercle, tibial articular surface, and fibular styloid) were also measured. The anterior ligament tibial attachment was a mean of 15.6 mm lateral and posterior to Gerdy's tubercle and 17.3 mm anterior and inferior from the fibular styloid. Posterior ligament tibial insertion was a mean of 15.7 mm inferior to the tibial articular surface on the tibial side and 14.2 mm medial and slightly inferior from the fibular styloid. Definable ligaments provide stability to the proximal tibiofibular joint and can be reconstructed in an anatomic fashion using the landmarks and parameters described. This information allows for an anatomic reconstruction of the proximal tibiofibular joint, which should provide patients with better outcomes and fewer postoperative sequelae. PMID:23276353

See, Aaron; Bear, Russell R; Owens, Brett D

2013-01-01

281

Novel gap alignment sensor for high-resolution proximity lithography  

NASA Astrophysics Data System (ADS)

The control of very small distances is essential for many applications and alignment procedures in the field of micro technology, e.g. micro lithography for MEMS or micro optics, where proximity lithography is often used for cost effective mass fabrication. Also in proximity lithography the requirements, especially for resolution, are increasing permanently. Recently new techniques have been developed to get sub-micron resolution even for larger distances between mask and substrate. But then also the proximity distance has to be controlled with sub-micron accuracy. A passive and an active sensor concept have been developed based on triangulation using diffractive structures. The required sensing patterns are implemented directly in the photo mask. In the passive gap alignment the distance can be reconstructed from the resist pattern obtained as a result of a lithographic step in which the diffractive sensor structure is exposed in the Mask-Aligner. In the active configuration the proximity gap can be controlled already during the alignment procedure prior to the lithographic exposure. A collimated laser beam irradiates a diffractive structure in the photo mask, which deflects the beam which will be reflected from the resist coated substrate towards the mask. A second mask structure, which is placed in a defined lateral distance to the first one, acts then as a ruler for the distance between mask and wafer and can be observed through the alignment microscope or a camera module. The design and fabrication of the diffractive structures, the measurement results for the full-wafer proximity distance distribution according to the passive method, as well as the realization of an active sensor module for mask aligners are presented in this paper.

Harzendorf, Torsten; Stuerzebecher, Lorenz; Zeitner, Uwe D.

2012-05-01

282

Role of diacylglycerol in adrenergic-stimulated sup 86 Rb uptake by proximal tubules  

SciTech Connect

We used rat proximal tubule fragments purified by Percoll centrifugation to examine the role of diacylglycerol (DAG) in noradrenergic-stimulated Na+ reabsorption. Tubular DAG concentration and ouabain-inhibitable 86Rb uptake increased within 30 s after adding norepinephrine (NE) and remained elevated for at least 5 min. NE (1 microM) increased DAG content 17% and ouabain-inhibitable 86Rb uptake 23%. Cirazoline-stimulated 86Rb uptake was not inhibited by BaCl, quinidine, or bumetanide (1-10 microM) or by the omission of HCO3- or Cl- from the medium, but it was completely inhibited by ouabain and furosemide. Oleoyl-acetyl glycerol, L-alpha-1,2-dioctanoylglycerol, and L-alpha-1,2-dioleoylglycerol (DOG) increased total 86Rb uptake 8-11%. 12-O-tetradecanoylphorbol-13-acetate (TPA) (5 nM) increased uptake by only 4%. Staurosporine at 5 nM inhibited DOG stimulation completely, whereas 50 nM staurosporine was required to inhibit NE stimulation completely. Sphingosine inhibited DOG stimulation by 66% but did not inhibit NE stimulation. Amiloride (1 mM) completely blocked DOG stimulation. Monensin increased 86Rb uptake 31% and completely blocked the DOG effect but reduced the NE effect by only 26% (P = 0.08). In tubules from salt-loaded rats, NE did not increase DAG concentration, but NE-stimulated 86Rb uptake was reduced by only 23% (P = 0.15). Thus DAG released by NE may stimulate Na+ entry through Na(+)-H+ exchange. NE predominantly stimulates Na(+)-K(+)-adenosinetriphosphatase (ATPase) by activating a protein kinase that is insensitive to DAG and TPA and is inhibited by staurosporine but not by sphingosine. NE may also stimulate K+ efflux through a BaCl-insensitive K+ channel that is inhibited by millimolar furosemide.

Baines, A.D.; Drangova, R.; Ho, P. (Univ. of Toronto, Ontario (Canada))

1990-05-01

283

FGF23 acts directly on renal proximal tubules to induce phosphaturia through activation of the ERK1/2-SGK1 signaling pathway  

PubMed Central

Fibroblast growth factor-23 (FGF23) is a bone-derived endocrine regulator of phosphate homeostasis which inhibits renal tubular phosphate reabsorption. Binding of circulating FGF23 to FGF receptors in the cell membrane requires the concurrent presence of the co-receptor ?Klotho. It is still controversial whether ?Klotho is expressed in the kidney proximal tubule, the principal site of phosphate reabsorption. Hence, it has remained an enigma as to how FGF23 downregulates renal phosphate reabsorption. Here, we show that renal proximal tubular cells do express the co-receptor ?Klotho together with cognate FGF receptors, and that FGF23 directly downregulates membrane expression of the sodium-phosphate cotransporter NaPi-2a by serine phosphorylation of the scaffolding protein Na+/H+ exchange regulatory cofactor (NHERF)-1 through ERK1/2 and serum/glucocorticoid-regulated kinase-1 signaling.

Andrukhova, Olena; Zeitz, Ute; Goetz, Regina; Mohammadi, Moosa; Lanske, Beate; Erben, Reinhold G.

2012-01-01

284

Interlaminated ice-proximal glacimarine sediments in Muir Inlet, Alaska  

USGS Publications Warehouse

Muir Inlet in Glacier Bay, Alaska, is a glacial fjord receiving a tremendous volume of sediment annually. The rate of sediment accumulation is greatest proximal to Muir Glacier (about 9 m yr-1) and decreases away from the glacier. The primary sediment sources are meltwater streams discharging at subglacial and ice-marginal positions to form overflows, interflows, and underflows (continuous turbidity currents). Overflows and interflows interact with diurnal tidal currents and their volume and sediment concentration varies diurnally and annually with meltwater discharge. These effects produce cyclic deposits of a thin fine-grained sand or silt lamina that grades normally to a thicker poorly to very poorly sorted mud lamina. This lamina couplet is termed a cyclopel. Underflows are suggested to occur in this glacimarine environment because of conditions unique to subglacial fluvial systems. Underflow deposits occur only in proximal positions (177 ??m) is ubiquitous, though low (<5% by weight), and occurs as isolated particles, frozen pellets, or as lenses that in cores may have a lamina appearance. Proximally, ice-rafted debris is difficult to identify because proximal sediment is often as coarse-grained. Deposited sediment may be reworked by tidal currents, and sediment gravity flows. Depositional processes operating in Muir Inlet produce interlaminated sand/silt/clay that characterizes sediment proximal to a glacier and fines seaward to mud. Sediment is classified into one of three sediment types: 1. (1) Type I sediment is very fine grained (mean 8.65-7.17 ??), low in sand (0.1-11.2%), and very poorly to poorly sorted. It is the dominant sediment type in Muir Inlet, and is transported by plumes and deposited by suspension settling. 2. (2) Type II sediment is fine- to coarse-grained (mean 6.70-3.12 ??), low to high in sand (5.1-86.6%), and very poorly to moderately sorted. It represents reworked sediment, proximal plume deposits, or coarse-grained laminae of cyclopels. 3. (3) Type III sediment is coarse-grained (mean 3.89-2.38 ??), high in sand (58.0-100.0%), and poorly to well sorted. It is deposited by sediment gravity flows or underflows. ?? 1984.

Mackiewicz, N. E.; Powell, R. D.; Carlson, P. R.; Molnia, B. F.

1984-01-01

285

Urea transport in the proximal tubule and the descending limb of Henle  

PubMed Central

Urea transport in proximal convoluted tubule (PCT) and descending limb of Henle (DLH) was studied in perfused segments of rabbit nephrons in vitro. Active transport of urea was ruled out in a series of experiments in which net transport of fluid was zero. Under these conditions the collected urea concentration neither increased nor decreased when compared to the mean urea concentration in the perfusion fluid and the bath. Permeability coefficient for urea (Purea) was calculated from the disappearance of urea-14C added to perfusion fluid. Measurements were obtained under conditions of zero net fluid movement: DLH was perfused with isosmolal ultrafiltrate (UF) of the same rabbit serum as the bath, while PCT was perfused with equilibrium solution (UF diluted with raffinose solution for fluid [Na] = 127 mEq/liter). Under these conditions Purea per unit length was 3.3±0.4 × 10-7 cm2/sec (5.3±0.6 × 10-5 cm/sec assuming I.D. = 20?) in PCT and 0.93±0.4 × 10-7 cm2/sec (1.5±0.5 × 10-5 cm/sec) in DLH. When compared to previously published results, these values show that the PCT is 2.5 times less permeable to urea than to Na, while the DLH is as impermeable to urea as to Na. These results further indicate that the DLH is less permeable to both Na and urea than the PCT. The reflection coefficient for urea, ?urea, was calculated as the ratio of induced solution efflux when 95 mOsm/liter of urea was added to the bath, as compared to net fluid movement induced by addition to the bath of equivalent amount of raffinose, ?urea in DLH is 0.95±0.4 as compared to 0.91±0.05 in PCT. ?urea in DLH is approximately equal to ?Na; however, ?urea in PCT is higher than ?Na (0.68). Several types of studies were conducted to examine the role of urea and urea plus sodium chloride in concentrating the fluid in the DLH. From the obtained results it was concluded that the intraluminal fluid of DLH is primarily concentrated by abstraction of water without significant net entry of solute. These results are discussed with respect to possible significance in the overall operation of the countercurrent system.

Kokko, Juha P.

1972-01-01

286

Hybrid bounding volume hierarchies for fast proximity queries  

NASA Astrophysics Data System (ADS)

A collision query determines the intersection between given objects, and is used in computer-aided design and manufacturing, animation and simulation systems, and physically-based modeling. Bounding volume hierarchies are one of the simplest and most widely used data structures for performing collision detection on complex models. This paper presented hierarchy of oriented rounded bounding volume for fast proximity queries. Designing hierarchies of new bounding volumes was use to combine multiple bounding volume types in a single hierarchy. The new bounding volume corresponds to geometric shape composed of a core primitive shape grown outward by some offset such as the Minkowski sum of rectangular box and a sphere shape. In the experiment of parallel close proximity, a number of benchmarks to measure the performance of the new bounding box and compare to that of other bounding volumes.

Kim, Dae-Hyun; Choi, Han-Soo

2005-12-01

287

Elements of proximal formative assessment in learners' discourse about energy  

NSDL National Science Digital Library

Proximal formative assessment, the just-in-time elicitation of students' ideas that informs ongoing instruction, is usually associated with the instructor in a formal classroom setting. However, the elicitation, assessment, and subsequent instruction that characterize proximal formative assessment are also seen in discourse among peers. We present a case in which secondary teachers in a professional development course at SPU are discussing energy flow in refrigerators. In this episode, a peer is invited to share her thinking (elicitation). Her idea that refrigerators move heat from a relatively cold compartment to a hotter environment is inappropriately judged as incorrect (assessment). The "instruction" (peer explanation) that follows is based on the second law of thermodynamics, and acts as corrective rather than collaborative.

Harrer, Benedikt W.; Scherr, Rachel E.; Wittmann, Michael C.; Close, Hunter G.; Frank, Brian W.

2012-05-15

288

Scintillation Proximity Radioimmunoassay Utilizing 125I-Labeled Ligands  

NASA Astrophysics Data System (ADS)

A unique type of radioimmunoassay is described that does not require centrifugation or separation. Microbeads containing a fluorophor are covalently linked to antibody. When an 125I-labeled antigen is added it binds to the beads and, by its proximity, the emitted short-range electrons of the 125I excite the fluorophor in the beads. The light emitted can be measured in a standard scintillation counter. Addition of unlabeled antigen from tissue extracts displaces the labeled ligand and diminishes the fluorescent signal. Application of scintillation proximity immunoassay to tissue enkephalins, serum thyroxin, and urinary morphine is described. Applications of the principle to study the kinetics of interaction between receptors and ligands are discussed.

Udenfriend, Sidney; Diekmann Gerber, Louise; Brink, Larry; Spector, Sydney

1985-12-01

289

Shoulder hemiarthroplasty for fractures of the proximal humerus.  

PubMed

Proximal humeral fractures were managed with primary hemiarthroplasty in 57 patients, 53 women (93%) and 4 men (7%) aged 51-87 years (mean 72.2). The mean follow-up period was 52 months (range 12-98), and the mean Constant score was 59.2 (range 38-76). Patients were very satisfied (n = 19); satisfied (n = 32) or dissatisfied with the outcome (n = 5). One patient required early revision surgery. Surgical treatment of three- and four-part fractures of the proximal humerus with hemiarthroplasty is a safe and effective approach, the outcome of which appears to be related to the quality of the anatomical reconstruction of the tuberosities. PMID:21503723

Castricini, R; De Benedetto, M; Pirani, P; Panfoli, N; Pace, N

2011-07-01

290

Thin film studies of the proximity Josephson effect  

NASA Astrophysics Data System (ADS)

The topics of theoretical and experimental interest in this research have been: The Proximity Induced Josephson Effect (PIJE), an effect occurring at a Normal Metal/Superconductor (N/S) interface which displays many of the features of the Josephson effect, the device potential of which has not been at all explored; the design and construction of a cryogenic scanning tunneling microscope capable of operating in ultra high vacuum. The Proximity Induced Josephson Effect (PIJE) has been observed at a Normal Metal/Superconductor (N/S) interfaces in point contact NS systems, and displays features resembling the Josephson effect. In experiments with Nb and Ta probes contacting MO and UBe13 (normal state) surface, the I(V) exhibit a low resistance segment centered at zero bias current resembling a Josephson current with a small series resistance R*, which has been interpreted as a spreading resistance in the normal state electrode.

Wolf, E. L.

1993-09-01

291

Two patients with a complete proximal rupture of the hamstring.  

PubMed

Two men visited our Emergency Room because of a water-ski-accident. At physical examination, there was hematoma at the upper leg with loss of strength at extension of the hip and flexion of the knee. Both patients had a palpable gap just distal of the ischial tuberosity. Further imaging by sonography and MR-scan showed a rupture of the proximal hamstring tendon. Treatment was operative refixation of the hamstring tendons at the ischial tuberosity. After treatment consisted of brace for 4 weeks after operation. Both patients returned to their pre-operatively sports, though at a lower level. Surgical treatment of a complete proximal rupture of the hamstrings is recommended in case of sportive patients. PMID:19688217

Floor, Sebastiaan; van der Veen, Alex H; Devilee, Roger J

2009-08-18

292

Office paper recycling: A function of container proximity  

PubMed Central

We investigated the effects of proximity of containers on pounds of office paper recycled and not recycled by 25 employees. During a memo and central container condition, one container for recyclable paper was provided; in a memo and local container condition, desktop recycling bins, announced by memo, were successively introduced across administrative, office, and instructional settings using a multiple baseline design. Only 28% of paper was recycled in the central container condition, but when recycling containers were placed in close proximity to participants, 85% to 94% of all recyclable paper was recycled. Follow-up assessments, conducted 1, 2, 3, and 7 months after all settings received local recycling containers, showed that 84% to 98% of paper was recycled. Providing desktop recycling containers was a cost-effective procedure with long-term maintenance and program survival.

Brothers, Kevin J.; Krantz, Patricia J.; McClannahan, Lynn E.

1994-01-01

293

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors  

SciTech Connect

We have found experimentally that the critical current of a square thin-film superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T, a behavior that has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. As a consequence, the effective transition temperature T{sub c} of the TES is current dependent and at fixed current scales as 1/L{sup 2}. We have also found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. We have observed the longitudinal proximity effect in these devices over extraordinarily long lengths up to 290 {micro}m, 1450 times the mean-free path.

Sadleir, John E.; Smith, Stephen J.; Bandler, Simon R.; Chervenak, James A.; Clem, John R.

2010-01-29

294

Elements of proximal formative assessment in learners' discourse about energy  

NASA Astrophysics Data System (ADS)

Proximal formative assessment, the just-in-time elicitation of students' ideas that informs ongoing instruction, is usually associated with the instructor in a formal classroom setting. However, the elicitation, assessment, and subsequent instruction that characterize proximal formative assessment are also seen in discourse among peers. We present a case in which secondary teachers in a professional development course at SPU are discussing energy flow in refrigerators. In this episode, a peer is invited to share her thinking (elicitation). Her idea that refrigerators move heat from a relatively cold compartment to a hotter environment is inappropriately judged as incorrect (assessment). The "instruction" (peer explanation) that follows is based on the second law of thermodynamics, and acts as corrective rather than collaborative.

Harrer, Benedikt W.; Scherr, Rachel E.; Wittmann, Michael C.; Close, Hunter G.; Frank, Brian W.

2012-02-01

295

Optical rule checking for proximity-corrected mask shapes  

NASA Astrophysics Data System (ADS)

Optical Rule Checking (ORC) is an important vehicle to predict the failure of wafer shapes due to the process proximity effects. Optical Proximity Correction (OPC) if not aided by ORC may cause severe failures affecting the yield in manufacturing. However, it is fairly complicated to do ORC on mask shapes that are pre-corrected either by rules-based or by model-based OPC. ORC is also a good tool to capture the problems that may occur at multi-layer interactions. We present a methodology to use both geometric directives and limited optical simulation to detect potential failures using ORC. We extend our methodology to multi-layer interactions. In case of multi-layer ORC, we present several approaches that deal with how to judiciously mix the geometric directives and the optical simulations for different layers. We show the ORC can help us design better rules for OPC.

Mukherjee, Maharaj; Baum, Zachary; Nickel, John; Dunham, Timothy G.

2003-06-01

296

Scintillation proximity radioimmunoassay utilizing 125I-labeled ligands  

SciTech Connect

A unique type of radioimmunoassay is described that does not require centrifugation or separation. Microbeads containing a fluorophor are covalently linked to antibody. When an /sup 125/I-labeled antigen is added it binds to the beads and, by its proximity, the emitted short-range electrons of the /sup 125/I excite the fluorophor in the beads. The light emitted can be measured in a standard scintillation counter. Addition of unlabeled antigen from tissue extracts displaces the labeled ligand and diminishes the fluorescent signal. Application of scintillation proximity immunoassay to tissue enkephalins, serum thyroxin, and urinary morphine is described. Applications of the principle to study the kinetics of interaction between receptors and ligands are discussed.

Udenfriend, S.; Gerber, L.D.; Brink, L.; Spector, S.

1985-12-01

297

Analysis of failed Van Straten LPM proximal interphalangeal prostheses.  

PubMed

The two-piece Van Straten Leuwen Poeschmann Metal (LPM) prosthesis was intended for the proximal interphalangeal joints. However, revision rates of 29% after 19 months were reported, as well as massive osteolysis. Five failed LPM titanium-niobium coated cobalt chromium components were obtained, three distal and two proximal, and subjected to a forensic retrieval analysis. Components were analyzed using a Talysurf contacting profilometer, ZYGO noncontacting profilometer, and environmental-scanning electron microscope. All components were heavily worn. In some regions the titanium-niobium coating had been scratched and penetrated. Elsewhere this coating had been removed where there was minimal scratching, which may have been due to corrosion between the coating and substrate. The osteolysis reported clinically was likely to be linked to the wear debris from the failed titanium-niobium coating and substrate. PMID:22989733

Bone, M C; Cunningham, J L; Lord, J; Giddins, G; Field, J; Joyce, T J

2012-09-18

298

Proximity effect in MBE grown bismuth chalcogenide thin films  

NASA Astrophysics Data System (ADS)

Topological insulators (TIs) comprise a new state of matter which provides access to novel physics. Of the set of materials that have exhibited spectroscopic evidence of topologically protected surface states, bismuth chalcogenide systems have garnered particular interest due to their relatively large nominal bulk band gap and single Dirac cone near the Fermi surface. We are studying the superconducting proximity effect in MBE grown thin films of Bi2Se3, Bi2Te3, and ternary compounds. After in situ deposition of a low temperature superconductor, the films are patterned into devices containing a matrix of superconducting islands of tunable size and density on top of the TI layer. We discuss growth optimization, device processing, the role of the superconductor-TI interface, and proximity effect transport results.

Mulcahy, Brian; Zheng, Mao; Zhang, Can; Dove, Allison; Yoscovits, Zachary R.; Olson, Gustaf; Eckstein, James N.

2013-03-01

299

Do people remember the temporal proximity of unrelated events?  

PubMed

In the present study, we tested the ability to remember the temporal proximity of two unrelated events that had happened within 7 days of one another. In three experiments, 1,909 participants judged whether pairs of news events, ranging in age from 1 month to about 6 years, had occurred within a week of each other and, if not, how far apart they had occurred. Some event pairs were related, and others were unrelated. For unrelated event pairs, same-week and separation judgments were very poor. Accuracy was much greater for both kinds of judgments when the events were related. Participants often guessed the separation of unrelated event pairs, whereas they frequently deduced the separation or remembered the proximity of related event pairs. For both types of pairs, the participants reported using the strength of the memories or the general period in which the events had occurred. PMID:21156875

Friedman, William J; Janssen, Steve M J

2010-12-01

300

Metabolic Requirement for Inorganic Phosphate by the Rabbit Proximal Tubule  

PubMed Central

These studies examine the effects of acute changes in the availability of inorganic phosphate on the function of isolated proximal renal tubules from rabbit kidney. We removed phosphate from the extracellular fluids and measured fluid absorption rates in isolated perfused tubules and oxygen consumption rates in suspensions of cortical tubules. In proximal convoluted tubules, the selective removal of phosphate from the luminal fluid reduced fluid absorption rates from 1.11±0.12 to ?0.01±0.08 nl/mm · min. This effect on fluid absorption was dependent on the presence of glucose transport and metabolism. The addition of phlorizin to the phosphate-free luminal fluid preserved fluid absorption rates (1.12±0.12 nl/mm · min) as did the substitution of nonmetabolized ?-methyl d-glucopyranoside for glucose (1.05±0.21 nl/mm · min) or the addition of 2-deoxyglucose, an inhibitor of glycolysis, to the bathing medium (1.01±0.15 nl/mm · min). There was no effect on fluid absorption if phosphate was removed from the bath only. Additionally, removal of phosphate from the luminal fluid of proximal straight rather than convoluted tubules had no effect on fluid absorption rates. Oxygen consumption rates in suspensions of cortical tubules were reduced from 18.9±0.6 to 10.6±0.6 nmol O2/mg tubular protein · min by the removal of phosphate from the medium. This inhibition was prevented by the substitution of ?-methyl d-glucopyranoside for glucose in the phosphate-free medium. The data indicate that under certain conditions, proximal convoluted tubules require the presence of phosphate in the luminal fluid to preserve tubular function. In the absence of intraluminal phosphate, glucose metabolism causes a reduction in both oxidative metabolism and fluid absorption. This response is analogous to the Crabtree effect and suggests limitations on the intracellular availability of inorganic phosphate.

Brazy, Peter C.; Gullans, Steven R.; Mandel, Lazaro J.; Dennis, Vincent W.

1982-01-01

301

Spin-polarized proximity effect in superconducting junctions  

NASA Astrophysics Data System (ADS)

We study spin dependent phenomena in superconducting junctions in both ballistic and diffusive regimes. For ballistic junctions we study both ferromagnet/s- and d-wave superconductor junctions and two-dimensional electron gas/s-wave superconductor junctions with Rashba spin-orbit coupling. It is shown that the exchange field always suppresses the conductance while the Rashba spin-orbit coupling can enhance it. In the latter part of the article we study the diffusive ferromagnet/insulator/s- and d-wave superconductor (DF/I/S) junctions, where the proximity effect can be enhanced by the exchange field in contrast to common belief. This resonant proximity effect in these junctions is studied for various situations: conductance of the junction and density of states of the DF are calculated by changing the heights of the insulating barriers at the interfaces, the magnitudes of the resistance in DF, the exchange field in DF, the transparencies of the insulating barriers and the angle between the normal to the interface and the crystal axis of d-wave superconductors ?. It is shown that the resonant proximity effect originating from the exchange field in DF strongly influences the tunneling conductance and density of states. We clarify the followings: for s-wave junctions, a sharp zero bias conductance peak (ZBCP) appears due to the resonant proximity effect. The magnitude of this ZBCP can exceed its value in normal states in contrast to that observed in diffusive normal metal/superconductor junctions. We find similar structures to the conductance in the density of states. For d-wave junctions at ?=0, we also find a result similar to that in s-wave junctions. The magnitude of the resonant ZBCP at ?=0 can exceed that at ?/?=0.25 due to the formation of the mid gap Andreev resonant states. To cite this article: T. Yokoyama, Y. Tanaka, C. R. Physique 7 (2006).

Yokoyama, Takehito; Tanaka, Yukio

2006-01-01

302

Complex of myoglobin with phenol bound in a proximal cavity.  

PubMed

Sperm whale myoglobin (Mb) has weak dehaloperoxidase activity and catalyzes the peroxidative dehalogenation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloroquinone. Crystals of Mb and of its more active G65T variant were used to study the binding of TCP, 4-iodophenol (4-IP) and phenol. The structures of crystals soaked overnight in a 10?mM solution of phenol revealed that a phenol molecule binds in the proximal cavity, forming a hydrogen bond to the hydroxyl of Tyr146 and hydrophobic contacts which include interactions with C? and C? of the proximal histidine His93. The phenol position corresponds to the strongest xenon binding site, Xe1. It appears that the ligand enters the proximal cavity through a gate formed by the flexible loops 79-86 and 93-103. TCP and 4-IP do not bind to Mb in this manner under similar conditions; however, it appears to be likely that dimethyl sulfoxide (DMSO), which was used at a concentration of 0.8?M to facilitate 4-IP dissolution, binds in the phenol/Xe1 binding site. In this structure, a water molecule coordinated to the heme iron was replaced by an oxygen molecule, reflecting the reduction of the heme. Crystals of Mb and G65T Mb soaked for 5-10?min did not show bound phenol. Kinetic studies of TCP dechlorination showed that phenol has a dual effect: it acts as a competitive inhibitor that is likely to interfere with TCP binding at the heme edge and as a weak activator, likely through binding in the proximal cavity. The lack of phenol bound at the heme edge in the crystal structures suggests that its inhibitory binding only takes place when the heme is activated by hydrogen peroxide. PMID:23192025

Huang, Xiao; Wang, Chunxue; Celeste, Lesa R; Lovelace, Leslie L; Sun, Shenfang; Dawson, John H; Lebioda, Lukasz

2012-11-19

303

[Proximal autosomal recessive types of spinal muscular atrophy].  

PubMed

One hundred and three patients with spinal muscular atrophy (SMA) were registered in a population medical genetic study of autosomal recessive childhood proximal SMA in Saratov region. Twenty-five patients were investigated complexly, using biochemical analysis of some enzymes, electroneuromyography, magnetic resonance imaging of spinal cord, muscle biopsy and molecular genetic testing. Pronounced clinical polymorphism and genetic heterogeneity of the disease were revealed. PMID:14564781

Kolokolov, O V; Iudina, G K; Solovykh, N N; Evgrafov, O V

2003-01-01

304

Interlanguage pragmatics in the zone of proximal development  

Microsoft Academic Search

Vygotsky’s zone of proximal development (ZPD) has been fruitfully applied in L2 research that examines second and foreign language learning. This paper considers the applicability of the ZPD to interlanguage pragmatics instruction and research. First, the ZPD is defined [Vygotsky, L.S., 1978. Mind in Society: The Development of Higher Psychological Processes. Harvard University Press, Cambridge, MA], and definitions are queried

Amy Snyder Ohta

2005-01-01

305

Implementation and development of compact UWB proximity fuze sensor system  

Microsoft Academic Search

A novel implementation of a low-cost proximity fuze sensor system is presented. This system has very small dimension with 40mm diameter and 25mm high, which can detect the target of a fixed distance, with a resolution of less than 20cm. The pulse generated by S RD (step recovery diode) is approximate Gaussian pulse, which have pulse duration of about 250ps

Zhao-Bo Li

2011-01-01

306

Direction Versus Proximity in the Social Influence Process  

Microsoft Academic Search

Rabinowitz and Macdonald (Am Polit Sci Rev 83(1):93–121, 1989) have advanced a directional theory of electoral choice that\\u000a stands as an alternative to the proximity models that have dominated thinking in this area for a number of years. In this\\u000a paper, we assess the utility of directional theory in another area of political behavior: the evaluation and influence of\\u000a politically

Christopher Kenny; Eric Jenner

2008-01-01

307

Essential genes in proximal 3L heterochromatin of Drosophila melanogaster  

Microsoft Academic Search

We have further characterized essential loci within the centric heterochromatin of the left arm of chromosome 3 (3L) of Drosophila melanogaster, using EMS, radiation and P element mutagenesis. We failed to find any new essential genes, a result that suggests a lower-than-average gene density in this region. Mutations affecting expression of the most proximal gene [lethal 1, l1 or l(3)80Fj

S. Schulze; D. A. R. Sinclair; E. Silva; K. A. Fitzpatrick; M. Singh; V. K. Lloyd; K. A. Morin; J. Kim; D. G. Holm; J. A. Kennison; B. M. Honda

2001-01-01

308

High-density data storage using proximal probe techniques  

Microsoft Academic Search

We describe some of the achievements and problems associated with proximal probe-based approaches to high-density data storage. While STM-based methods have demonstrated spectacular areal densities dwarfing anything achievable with today's storage technologies, reliability and data rate issues present serious obstacles. These problems have led us to focus on techniques based on AFM and near-field optics. First, we have developed a

H. Jonathon Mamin; Bruce D. Terris; Long-sheng Fan; Storrs Hoen; Robert C. Barrett; Daniel Rugar

1995-01-01

309

Treatment of proximal humerus fracture using multiple intramedullary flexible nails  

Microsoft Academic Search

A total of 61 patients with a proximal humeral fracture was treated between January 1996 and March 1998 by closed reduction\\u000a and fracture fixation with intramedullary Prvot (or Nancy) nails. Of these, 28 female and 25 male patients with a mean age\\u000a of 52 years (range 3–91 years) were reviewed clinically and radiologically with a mean follow-up of 17 months

S. W. Wachtl; C. B. Marti; H. M. Hoogewoud; R. P. Jakob; E. Gautier

2000-01-01

310

Water fluoride concentration and fracture of the proximal femur  

Microsoft Academic Search

STUDY OBJECTIVE--The aim of the study was to examine the relationship between water fluoride concentration and the incidence of hip fracture, since evidence on this is at present inconsistent. DESIGN--Numbers of hospital admissions for fractures of proximal femur were obtained from hospital activity analysis data for the years 1978-1982. The fracture rates were compared with water fluoride concentrations in 39

C Cooper; C Wickham; R F Lacey; D J Barker

1990-01-01

311

On Strong Inclusions and Asymmetric Proximities in Frames  

Microsoft Academic Search

The strong inclusion, a specific type of subrelation of the order of a lattice with pseudocomplements, has been used in the\\u000a concrete case of the lattice of open sets in topology for an expedient definition of proximity, and allowed for a natural\\u000a pointfree extension of this concept. A modification of a strong inclusion for biframes then provided a pointfree model

Jorge Picado; Aleš Pultr

312

Towards Core Body Temperature Measurement via Close Proximity Radiometric Sensing  

Microsoft Academic Search

Presented is a noncontact model and radiometric sensor developed to facilitate core body temperature extraction. The system has been designed as a close-proximity sensor to detect thermal emissions radiated from deep inside the human body. The radiometer uses a cavity-backed slot antenna (CBSA) designed to account for performance degradation which occurs in the near field of the human body. Tissue-simulating

Quenton Bonds; John Gerig; Thomas M. Weller; Paul Herzig

2012-01-01

313

Improvement of Negative Bias Temperature Instability by Stress Proximity Technique  

Microsoft Academic Search

The stress proximity technique (SPT) is found to improve negative bias temperature instability (NBTI) in p-channel metal-oxide-semiconductor field-effect transistors significantly. A first-principles calculation is carried out to examine the effect of strain on NBTI, and a process simulation is conducted to determine the change in stress profile in the device induced by SPT. The first-principles calculation shows that a larger

Jian Bo Yang; T. P. Chen; Ying Gong; Shyue Seng Tan; Chee Mang Ng; Lap Chan

2010-01-01

314

The role of renal proximal tubular cells in diabetic nephropathy  

Microsoft Academic Search

We now know that the rate of progression of diabetic nephropathy, like all progressive renal disease, correlates with the\\u000a degree of corticointerstitial fibrosis. Therefore, much interest has focused on the contribution of the resident cells in\\u000a the renal cortex to this process. This article reviews the evidence that the epithelial cells of the proximal tubule are major\\u000a players in orchestrating

Aled O. Phillips

2003-01-01

315

Current-induced voltage transients in Necturus proximal tubule  

Microsoft Academic Search

Summary Transients in the potential difference spontaneously developed by theNecturus proximal tubule were characterized during and after voltage or current clamp commands. These voltage transients were adequately fitted by an exponential function similar to that describing the ionic charging of a leaky fluid capacitance and were slower during clamp periods (t 1\\/2=0.98 min) than after release of the clamp (t

Kenneth R. Spring

1973-01-01

316

Full-chip optical proximity correction using lithography simulation  

Microsoft Academic Search

The application of Optical Proximity Correction for improving uniformity of printed dimensions at sub-half-micron resolution in a 0.35 micron CMOS process is described. Results are presented in terms of measurements made on polysilicon gates, at different pitches, which are compared to the uncorrected case. The impact of photomask and stepper lens qualities on dimensional control are also considered. Results presented

Graham G. Arthur; Brian Martin; Christine Wallace; Anja Rosenbusch; Huw Fryer

1998-01-01

317

Proximal femur bone mineral levels of US adults  

Microsoft Academic Search

This paper describes bone mineral levels in the proximal femur of US adults based on a nationally representative sample of 7116 men and women aged 20 years and older. The data were collected in phase 1 of the third National Health and Nutrition Examination Survey (NHANES III, 1988–1991) using dual-energy X-ray absorptiometry, and included bone mineral density (BMD), bone mineral

A. C. Looker; H. W. Wahner; W. L. Dunn; M. S. Calvo; T. B. Harris; S. P. Heyse; C. C. Johnston; R. L. Lindsay

1995-01-01

318

Properties of the Proximate Parameter Tuning Regularization Algorithm  

Microsoft Academic Search

An important aspect of systems biology research is the so-called “reverse engineering” of cellular metabolic dynamics from\\u000a measured input-output data. This allows researchers to estimate and validate both the pathway’s structure as well as the kinetic\\u000a constants. In this paper, the recently published ‘Proximate Parameter Tuning’ (PPT) method for the identification of biochemical\\u000a networks is analysed. In particular, it is

Martin Brown; Fei He; Stephen J. Wilkinson

2010-01-01

319

Just-in-Time Manufacturing Systems, Subcontracting and Geographic Proximity  

Microsoft Academic Search

Holl A., Pardo R. and Rama R. Just-in-Time manufacturing systems, subcontracting and geographic proximity, Regional Studies. The paper studies the spatial extent of subcontracting linkages for a sample of medium-sized and large Spanish manufacturing firms operating in the automotive and electronics industries. In particular, it analyses how Just-in-Time (JIT) organization of production is related to the spatial pattern of these

Adelheid Holl; Rafael Pardo; Ruth Rama

2010-01-01

320

TECHNOLOGICAL CATCH-UP AND GEOGRAPHIC PROXIMITY &ast  

Microsoft Academic Search

ABSTRACT.?This paper examines productivity catch-up as a source of establishment productivity growth. We present evidence that, other things equal, establishments further behind the industry frontier experience faster rates of productivity growth. Geographic proximity to frontier firms makes catch-up faster. Our econometric specification implies a long-run relationship between productivity levels, where nonfrontier establishments lie a steady-state distance behind the frontier such

Rachel Griffith; Stephen Redding; Helen Simpsonz

2009-01-01

321

Revision total hip arthroplasty with proximal bone loss.  

PubMed

The presence of a deficient or mechanically compromised proximal femur represents a particular challenge to revision total hip arthroplasty. This article details the results of reconstructing these challenging cases using a modular, tapered, and distally fixed femoral stem component that allows independent control of length, offset, and anteversion of the femur. Mid-term results suggest that distal fixation in the presence of a deficient or mechanically compromised femur is a reliable solution to these difficult problems. PMID:15190565

Murphy, Stephen B; Rodriguez, Jose

2004-06-01

322

Proximal dentatothalamocortical tract involvement in posterior fossa syndrome  

PubMed Central

Posterior fossa syndrome is characterized by cerebellar dysfunction, oromotor/oculomotor apraxia, emotional lability and mutism in patients after infratentorial injury. The underlying neuroanatomical substrates of posterior fossa syndrome are unknown, but dentatothalamocortical tracts have been implicated. We used pre- and postoperative neuroimaging to investigate proximal dentatothalamocortical tract involvement in childhood embryonal brain tumour patients who developed posterior fossa syndrome following tumour resection. Diagnostic imaging from a cohort of 26 paediatric patients previously operated on for an embryonal brain tumour (13 patients prospectively diagnosed with posterior fossa syndrome, and 13 non-affected patients) were evaluated. Preoperative magnetic resonance imaging was used to define relevant tumour features, including two potentially predictive measures. Postoperative magnetic resonance and diffusion tensor imaging were used to characterize operative injury and tract-based differences in anisotropy of water diffusion. In patients who developed posterior fossa syndrome, initial tumour resided higher in the 4th ventricle (P = 0.035). Postoperative magnetic resonance signal abnormalities within the superior cerebellar peduncles and midbrain were observed more often in patients with posterior fossa syndrome (P = 0.030 and 0.003, respectively). The fractional anisotropy of water was lower in the bilateral superior cerebellar peduncles, in the bilateral fornices, white matter region proximate to the right angular gyrus (Tailerach coordinates 35, –71, 19) and white matter region proximate to the left superior frontal gyrus (Tailerach coordinates –24, 57, 20). Our findings suggest that multiple bilateral injuries to the proximal dentatothalamocortical pathways may predispose the development of posterior fossa syndrome, that functional disruption of the white matter bundles containing efferent axons within the superior cerebellar peduncles is a critical underlying pathophysiological component of posterior fossa syndrome, and that decreased fractional anisotropy in the fornices and cerebral cortex may be related to the abnormal neurobehavioural symptoms of posterior fossa syndrome.

Phillips, Nicholas S.; Laningham, Fred H.; Patay, Zoltan; Gajjar, Amar; Wallace, Dana; Boop, Frederick; Sanford, Robert; Ness, Kirsten K.; Ogg, Robert J.

2009-01-01

323

Metacognition of agency: proximal action and distal outcome.  

PubMed

The cues contributing to people's metacognitions of agency were investigated in two experiments in which people played a computer game that involved trying to "touch", via a mouse moving a cursor, downward scrolling X's (Experiment 1), or trying to "explode" the downward scrolling X's (Experiment 2). Both experiments varied (a) proximal action-related information by either introducing or not introducing Turbulence into the mouse controls and (b) distal outcome-related information such that touched X's "exploded" either 100 or 75 % of the time. Both variables affected people's judgments of agency (JOAs), but the effect was different. First, the decrement in feelings of agency was greater with the proximal variable than with distal variable. Second, while the proximal variable always had a large direct effect on JOAs, even taking judgments of performance (JOPs) into account, JOPs completely accounted for the effect of the distal variable in Experiment 1, where the instructions were just to touch the X's. And even in Experiment 2, in which the instructions were to explode the X's, the direct effect of the distal variable on JOAs was small. These data indicate that these two cues exhibit different psychological profiles. The proximal action-related information is a diagnostic cue to agency indicating the match between one's own intentions and actions. Internal monitoring of intentions is necessary and so the self is implicated. However, distal outcome can be largely monitored using information external to the agent, and so-while it is used by people to make agency judgments-it is a non-diagnostic cue. PMID:23358706

Metcalfe, Janet; Eich, Teal S; Miele, David B

2013-01-29

324

Do people remember the temporal proximity of unrelated events?  

Microsoft Academic Search

In the present study, we tested the ability to remember the temporal proximity of two unrelated events that had happened within\\u000a 7 days of one another. In three experiments, 1,909 participants judged whether pairs of news events, ranging in age from 1\\u000a month to about 6 years, had occurred within a week of each other and, if not, how far

William J. Friedman; Steve M. J. Janssen

2010-01-01

325

Using Proximal Soil Sensors for Digital Soil Mapping  

Microsoft Academic Search

\\u000a There is a great need for soil data to be used in natural resource assessment and management, e.g. for environmental modelling\\u000a and digital soil mapping (DSM) to better understand soil processes and reduce risks in decision making. Conventional soil\\u000a survey cannot efficiently provide these data because the techniques are time consuming and expensive. Proximal soil sensing\\u000a (PSS) can be used

R. A. Viscarra Rossel; N. J. McKenzie; M. J. Grundy

326

Failure to demonstrate a hormonal inhibitor of proximal sodium reabsorption  

PubMed Central

Recently, it has been reported that a humoral inhibitor of proximal sodium reabsorption could be detected in plasma, and dialysates of plasma, of rats and dogs undergoing saline diuresis. We have repeated these studies using similar techniques and protocols. Fractional sodium reabsorption by the proximal tubule (as estimated in free-flow micropuncture studies from tubule fluid-to-plasma inulin ratios) was found not to be lower during infusion of “natriuretic” plasma than during subsequent infusion of “hydropenic” plasma. Similarly, infusion of natriuretic plasma failed to prolong reabsorptive half-time of the shrinking drop beyond that seen during hydropenic plasma infusion. No increase in urine volume or rate of sodium excretion was observed during the period of natriuretic plasma infusion, nor did natriuretic plasma result in an increase in these measures in rats undergoing water diuresis. It also has been reported that dialysates of natriuretic plasma, but not of hydropenic plasma, when placed directly into the tubule lumen, inhibit proximal sodium reabsorption. In double blind studies carried out independently in Bethesda, London, and Cologne, we failed to detect the presence of a dialyzable inhibitor in natriuretic plasma. Finally, in contrast to other recent reports, we were unable to detect inhibitory activity in plasma obtained from dogs during the “escape” phase of chronic deoxycorticosterone acetate administration.

Wright, Fred S.; Brenner, Barry M.; Bennett, Cleaves M.; Keimowitz, Robert I.; Berliner, Robert W.; Schrier, Robert W.; Verroust, Pierre J.; De Wardener, Hugh E.; Holzgreve, Heinz

1969-01-01

327

Trajectory generation for effective sensing of a close proximity environment  

NASA Astrophysics Data System (ADS)

Unmanned systems stand to play a significant role in future sensing and information gathering applications. The scope of these scenarios is expanding to include those missions for which the sensor and carrier vehicle are forced to operate in close proximity to the surrounding environment. Several unique challenges are introduced for this class of sensing problems. First, the sensor projects a small footprint on environment surfaces relative to the scale of vehicle motion. Consequently, coupling exhibited between the motion of the vehicle and the direction of sensor pointing has a significant effect on gathered data. Second, view characteristics of sensed objects, such as resolution and aspect, can vary appreciably over the sensor field-of-view. These variations can have an adverse effect on data quality. Finally, vehicle maneuvering in close proximity to obstacles imposes significant risks to safe navigation. As such, consideration of vehicle dynamics within any motion planning strategy is critical to ensure that accurate and precise trajectories are generated. This dissertation addresses the problem of planning sensing trajectories through complex and cluttered environments. A randomized planning technique is developed which utilizes a hybrid modeling strategy to efficiently plan dynamically-admissible trajectories. Then, a generalized measure of sensing effectiveness is formulated to quantify the application-specific effects of sensor operation in close proximity to sensing targets. Finally, these elements are integrated into a randomized trajectory planner that ensures quality data collection regarding a specified set of targets while satisfying the system dynamics. The utility of the planner is demonstrated through several simulated examples.

Kehoe, Joseph J.

328

The Significance of Splenectomy for Advanced Proximal Gastric Cancer  

PubMed Central

Objectives. The significance of splenectomy in advanced proximal gastric cancer is examined retrospectively. Methods. From 1994 to 2004, 505 patients with advanced proximal gastric cancer underwent curative total gastrectomy with preserving spleen (T) for 264 patients and total gastrectomy with splenectomy (ST) for 241 patients. Results. Patients who underwent splenectomy showed more advanced lesions. The metastatic rate of lymph node (LN) in the splenic hilus (No. 10) in ST was 18.3%. As for the incidence of surgical complications, there was not statistically difference except for pancreatic fistula. The index of estimated benefit of (No. 10) LN was 4.2, which was similar to that of (No. 9), (No. 11p), (No. 11d), and (No. 16) LNs. 5-year survival rate of (No. 10) positive group was 22.2%. 5-year survival rates of pSE and pN2 in T group were better than that of pSE and pN2 in ST, respectively. The superiority of ST was not confirmed even in Stage II, IIIA, and IIIB. Conclusion. Splenectomy was not effective for patients with (No. 10) metastasis in long-term survival. Spleen-preserving total gastrectomy will be feasible and be enough to accomplish radical surgery for locally advanced proximal gastric cancer.

Nashimoto, Atsushi; Yabusaki, Hiroshi; Matsuki, Atsushi

2012-01-01

329

Bipolar proximal femoral replacement prostheses for musculoskeletal neoplasms.  

PubMed

While bipolar proximal femoral replacement prostheses (PFRP) have become a common treatment for tumors of the proximal femur, long-term results are not specified in the literature. The objective was to determine the complication and revision rates of bipolar PFRP and compare them to historical controls of bipolar hemiarthroplasties for nontumor indications. Information was retrospectively collected on 62 patients who received bipolar PFRP with cemented diaphyseal stems for primary or metastatic disease of the proximal femur from 1981 to 2003. Mean followup was 5 years. Twelve of 62 (19%) bipolar PFRPs underwent revision. Aseptic loosening was the most common complication with six (10%) undergoing revision. None were converted to THA due to acetabular erosion. Three patients (5%) had problems with dislocation and three (5%) had deep infections. Mean MSTS functional rating was 71% of normal function. The limb salvage rate was 98% and the 5-year event-free prosthetic survival was 79%. Bipolar PFRPs were found to have higher revision, dislocation, and deep infection rates compared to bipolar hemiarthroplasty for nontumor indications, but a lower rate of conversion to THA due to acetabular erosion. Bipolar PFRPs have good long-term durability with some complications, but are able to preserve the limb and provide good function for patients. PMID:17545760

Finstein, Joseph L; King, Joseph J; Fox, Edward J; Ogilvie, Christian M; Lackman, Richard D

2007-06-01

330

Glutamatergic signaling maintains the epithelial phenotype of proximal tubular cells.  

PubMed

Epithelial-mesenchymal transition (EMT) contributes to the progression of renal tubulointerstitial fibrosis. The N-methyl-d-aspartate receptor (NMDAR), which is present in proximal tubular epithelium, is a glutamate receptor that acts as a calcium channel. Activation of NMDAR induces actin rearrangement in cells of the central nervous system, but whether it helps maintain the epithelial phenotype of the proximal tubule is unknown. Here, knockdown of NMDAR1 in a proximal tubule cell line (HK-2) induced changes in cell morphology, reduced E-cadherin expression, and increased ?-SMA expression. Induction of EMT with TGF-?1 led to downregulation of both E-cadherin and membrane-associated ?-catenin, reorganization of F-actin, expression of mesenchymal markers de novo, upregulation of Snail1, and increased cell migration; co-treatment with NMDA attenuated all of these changes. Furthermore, NMDA reduced TGF-?1-induced phosphorylation of Erk1/2 and Akt and the activation of Ras, suggesting that NMDA antagonizes TGF-?1-induced EMT by inhibiting the Ras-MEK pathway. In the unilateral ureteral obstruction model, treatment with NMDA blunted obstruction-induced upregulation of ?-SMA, FSP1, and collagen I and downregulation of E-cadherin. Taken together, these results suggest that NMDAR plays a critical role in preserving the normal epithelial phenotype and modulating tubular EMT. PMID:21597037

Bozic, Milica; de Rooij, Johan; Parisi, Eva; Ortega, Marta Ruiz; Fernandez, Elvira; Valdivielso, José M

2011-05-19

331

Cluster radioactivity using various versions of nuclear proximity potentials  

NASA Astrophysics Data System (ADS)

The systematic study of doubly closed shell 208Pb-daughter cluster radioactivity using different versions of proximity potentials within the preformed cluster-decay model is extended to daughter nuclei other than 208Pb. The nuclear proximity potentials used in the calculation of total interaction potential cover a wide range of barrier characteristics. The decay half-life of the cluster changes significantly with the use of these different potentials because of the corresponding change in the preformation probability (P0) and penetration probability (P) of the cluster. The cluster radioactivity is worked out at touching as well as at an elongated neck configuration by taking the neck-length parameter ?R=0.5 fm. In order to observe the effect of deformation, the spherical fragmentation of clusters is also taken into account and the standard root-mean-square (rms) deviation is also compared for the various nuclear proximity potentials. It is observed that Prox 1977 reproduces the experimental half-lives very well at ?R=0.5 fm and further improves upon the value obtained in previous work. Thus Prox 1977 turns out to be a better option for studying the cluster decay of radioactive nuclei; however, the calculated half-lives of 14C clusters are still poor. With the use of mod-Prox 1988, having stronger isospin and asymmetry dependence, the comparison for 14C clusters improves significantly and the standard rms deviation from experimental half-lives comes out to be 1.01 and 1.46 for spherical and deformed choices of fragmentation, respectively. The standard rms deviation reported for various proximity potentials can be further improved if the precise experimental half-lives of 15, out of the 45 clusters used in present study, are made available. Till now only lower limits are available for these clusters. The barrier characteristics of various interaction potentials obtained using different nuclear proximity potentials are also explored in the context of ground-state cluster radioactivity. The new cases of 34Si decay of 238U and 14C and 15N decays of 223Ac are also included in the present study of 45 clusters. Predictions of half-lives of possible cluster decays in the trans-lead region are also made using Prox 1977. The deformation effect is included with optimum cold orientations.

Kumar, Raj

2012-10-01

332

Correction for etch proximity: new models and applications  

NASA Astrophysics Data System (ADS)

Short-range etch proximity effects increase intra-die CD variability and degrade the IC performance and yield. Tight control of the etch bias is an increasingly critical factor in realizing the ITRS technology nodes. The 2000 technology nodes revision added a new category, the post-etch 'physical' gate length metric, that is 9 - 17% smaller than 'in-resist' gate length. We present new etch proximity correction methods and models designed to reduce negative impact of etch-induced CD variability and increase uniformity of the controlled over- etching. Resolution Enhancement Technologies (RET) design correction methods typically employ 'lumped' process models. We found that an alternative methodology based upon separation of the process factors and the related models may yield better accuracy, performance, and better suit the design and process optimization flows. The contributions from the reticle, the optics, the wafer, and etch are individually determined and then used either separately or in aggregation for the most flexible and optimum correction of their respective contributions. The etch corrections are based on the Variable Etch Bias model (VEB model). This semi-empirical model requires experimental CD information to be collected from the test patterns under fixed process conditions (point-process model). It demonstrates excellent fit to the early experimental CD-SEM data gathered to date, which spans a variety of layout features and process conditions. The VEB model works in conjunction with CalibreR software system's Variable Threshold Resist-Extended (VTR-E) model, however the etching is modeled separately from the optics and the resist processing. This yields better understanding and more accurate explanation of the experiments than those that are produced by the 'lumped' process modeling. The VEB model explains etch- induced bias in terms of the following three proximity characteristics or variables: effective trench width (or pattern separation), pattern density, and effective line width (or pattern granularity). We synthesized and studied their integral representations. Performance fitness of the various weighting, smoothing, and anisotropic integral kernels and their parameters were studied to correctly reflect the etch bias behavior on silicon. We found that depending on the resist composition and layer types (poly or metal), the etch bias can sometimes be explained only by one or two (out of three) proximity variables. The aperture and microloading etch effects are studied and shown to be correctly reflected in the model. We demonstrate how model-based corrections improve CD uniformity of the poly and metal layers by compensating for the iso/dense and inverse-iso/dense biases. More complicated 2-D proximity effects are also captured, which is confirmed by the comparison of the SEM images to the simulations.

Granik, Yuri

2001-09-01

333

Coordinated regulation of cardiac Na(+)/Ca (2+) exchanger and Na (+)-K (+)-ATPase by phospholemman (FXYD1).  

PubMed

Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the ?-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure. PMID:23224879

Cheung, Joseph Y; Zhang, Xue-Qian; Song, Jianliang; Gao, Erhe; Chan, Tung O; Rabinowitz, Joseph E; Koch, Walter J; Feldman, Arthur M; Wang, JuFang

2013-01-01

334

Intracellular pH regulation in the renal proximal tubule of the salamander. Basolateral HCO3- transport  

PubMed Central

We have used pH-, Na-, and Cl-sensitive microelectrodes to study basolateral HCO3- transport in isolated, perfused proximal tubules of the tiger salamander Ambystoma tigrinum. In one series of experiments, we lowered basolateral pH (pHb) from 7.5 to 6.8 by reducing [HCO3-]b from 10 to 2 mM at a constant pCO2. This reduction of pHb and [HCO3-]b causes a large (approximately 0.35), rapid fall in pHi as well as a transient depolarization of the basolateral membrane. Returning pHb and [HCO3-]b to normal has the opposite effects. Similar reductions of luminal pH (pHl) and [HCO3-]l have only minor effects. The reduction of [HCO3-]b and pHb also produces a reversible fall in aiNa. In a second series of experiments, we reduced [Na+]b at constant [HCO3-]b and pHb, and also observed a rapid fall in pHi and a transient basolateral depolarization. These changes are reversed by returning [Na+]b to normal. The effects of altering [Na+]l in the presence of HCO3-, or of altering [Na+]b in the nominal absence of HCO3-, are substantially less. Although the effects on pHi and basolateral membrane potential of altering either [HCO3-]b or [Na+]b are largely blocked by 4-acetamido-4- isothiocyanostilbene-2,2'-disulfonate (SITS), they are not affected by removal of Cl-, nor are there accompanying changes in aiCl consistent with a tight linkage between Cl- fluxes and those of Na+ and HCO3-. The aforementioned changes are apparently mediated by a single transport system, not involving Cl-. We conclude that HCO3- transport is restricted to the basolateral membrane, and that HCO3- fluxes are linked to those of Na+. The data are compatible with an electrogenic Na/HCO3 transporter that carries Na+, HCO3-, and net negative charge in the same direction.

1983-01-01

335

The office candy dish: proximity's influence on estimated and actual consumption  

Microsoft Academic Search

Objective and purpose:Although there is increasing interest in how environmental factors influence food intake, there are mixed results and misunderstandings of how proximity and visibility influence consumption volume and contribute to obesity. The objective of this paper is to examine two questions: first, how does the proximity and salience of a food influence consumption volume? Second, are proximate foods consumed

B Wansink; J E Painter; Y-K Lee

2006-01-01

336

Proximity mobile services: Neural network based connection admission controller and other issues  

Microsoft Academic Search

Proximity aware mobile service is a wireless application for mobile users to interact with services offered by service providers present in the user's environment. Many issues are still prevalent in this area which includes context modeling, sensors integration, proximity resolution and service management. One important aspect in service management is congestion control which plays a key part in providing proximity

Lim Luo Ren; Quah Jon Tong Seng

2009-01-01

337

Proximity mobile services: Neural network based connection admission controller and other issues  

Microsoft Academic Search

Proximity aware mobile service is a wireless application for mobile users to interact with services offered by service providers present in the user's environment. Many issues are still prevalent in this area which includes context modeling, sensors integration, proximity resolution and service management. One important aspect in service management is congestion control which plays a key part in providing proximity

J. T. S. Quah; Luo Ren Lim

2010-01-01

338

Proximity sensors utilizing an evanescent acoustic field formed by flexural plate waves  

Microsoft Academic Search

A proximity sensor utilizing an evanescent acoustic field formed by flexural plate waves is proposed. When an object comes into the evanescent field, the acoustic radiation admittance of the bending vibrator may change. Hence, the proximity sensing can be achieved by measuring the electrical admittance of the piezoelectric flexural vibrator. To confirm the characteristics of the proximity sensor, some experiments

S. Hongo; I. Naliamura; N. Hosokawa

1997-01-01

339

On the Role Played by Temporary Geographical Proximity in Knowledge Transmission  

Microsoft Academic Search

Torre A. On the role played by temporary geographical proximity in knowledge transmission, Regional Studies. This paper defends the thesis that geographical proximity remains essential for knowledge transfer, but not often implies the co-location of innovation and research activities. The need for geographical proximity now mostly affects certain stages of the process of production, research or development. Short- or medium-term

André Torre

2008-01-01

340

Human proximal tubular cell responses to angiotensin II analyzed using DNA microarray  

Microsoft Academic Search

Angiotensin II has been shown to exert complex effects on proximal tubular cell function and growth. To assess some of the direct effects on proximal tubular cells, changes in gene expression of selected cellular pathways were determined after exposure to angiotensin II. We used DNA microarrays to analyze multiple gene expression responses to increasing angiotensin II concentrations. Human proximal tubular

Branko Braam; Pat Allen; Ed Benes; Hein A Koomans; L. Gabriel Navar; Timothy Hammond

2003-01-01

341

Local organisations and institutions. How can geographical proximity be activated by collective projects?  

Microsoft Academic Search

This paper deals critically with the concept of geographical proximity as a prerequisite for successful regional innovation processes. Using three case studies we show that regional development studies need to connect geographical proximity with organisational proximity achieved by actions to mobilise resources around a collective project or utilising common institutional routines and values.

Maryline Filippi; Andre Torre

2003-01-01

342

Topology of the type IIa Na+/P(i) cotransporter.  

PubMed

The type IIa Na(+)/P(i) cotransporter (NaPi-IIa) plays a key role in the reabsorption of inorganic phosphate (P(i)) in the renal proximal tubule. The rat NaPi-IIa isoform is a protein of 637 residues for which different algorithms predict 8-12 transmembrane domains (TMDs). Epitope tagging experiments demonstrated that both the N and the C termini of NaPi-IIa are located intracellularly. Site-directed mutagenesis revealed two N-glycosylation sites in a large putative extracellular loop. Results from structure-function studies suggested the assembly of two similar opposed regions that possibly constitute part of the substrate translocation pathway for one phosphate ion together with three sodium ions. Apart from these topological aspects, other structural features of NaPi-IIa are not known. In this study, we have addressed the topology of NaPi-IIa using in vitro transcription/translation of HK-M0 and HK-M1 fusion vectors designed to test membrane insertion properties of cDNA sequences encoding putative NaPi-IIa TMDs. Based on the results of in vitro transcription/translation analyses, we propose a model of NaPi-IIa comprising 12 TMDs, with both N and C termini orientated intracellularly and a large hydrophilic extracellular loop between the fifth and sixth TMDs. The proposed model is in good agreement with the prediction of the NaPi-IIa structure obtained by the hidden Markov algorithm HMMTOP. PMID:17206517

Radanovic, Tamara; Gisler, Serge M; Biber, Jürg; Murer, Heini

2007-01-06

343

Proximate composition and caloric content of eight Lake Michigan fishes  

USGS Publications Warehouse

We measured the proximate composition (percentage lipid, water, fat-free dry material, ash) and caloric content of eight species of Lake Michigan fish: lake trout (Salvelinus namaycush), coho salmon (Oncorhynchus kisutch), lake whitefish (Coregonus clupeaformis), bloater (Coregonus hoyi), alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), deepwater sculpin (Myoxocephalus quadricornis), and slimy sculpin (Cottus cognatus). Except for alewives, proximate composition and caloric content did not differ significantly between males and females. And, for coho salmon, there was no significant difference in composition between fish collected in different years. Lipid and caloric content of lake trout increased directly with age. In all species examined, lipids and caloric contents were significantly lower in small, presumably immature, fish than in larger, older fish. Lipid content of lake trout, lake whitefish, and bloaters (range of means, 16-22%) was nearly 3 times higher than that of coho salmon, sculpins, rainbow smelt, and alewives (range of means, 5.2-7.0%). The mean caloric content ranged from 6.9 to 7.1 kcal/g for species high in lipids and from 5.8 to 6.3 kcal/g for species low in lipids. Although the caloric content of all species varied directly with lipid content and inversely with water content, an increase in lipid content did not always coincide with a proportional increase in caloric content when other components of fish composition were essentially unchanged. This observation suggests that the energy content of fish estimated from the proximate composition by using universal conversion factors may not necessarily be accurate.

Rottiers, Donald V.; Tucker, Robert M.

1982-01-01

344

[Results after osteosynthesis of extraarticular proximal phalangeal fractures].  

PubMed

The aim of the study was to retrospectively present and analyse the functional results of surgically treated extraarticular fractures of the proximal phalanx.From 1/2005-4/2008 we operated on 49 patients with 52 closed, extraarticular fractures of the proximal phalanx of the long fingers with either pins, screws or plates. 30 patients were male, 19 were female, the mean age was 35 years. Open fractures, fractures of the thumb and those with injuries to neurovascular structures or tendons were excluded. Postoperative physiotherapy was started on day 1 after surgery. Postoperative finger function and complications were analysed based on the total active motion (TAM) regarding the Belsky score and the classification of Page and Stern. In addition, patients were contacted by phone in 4/2009 to verify the subjective functional results at the end of the observation period.Three different operative procedures were employed: internal fixation by Kirschner wires (n=25), and open fixation by screws (n=8) or plates (n=19). The entire treatment period amounted to 12 (4-28) weeks, the observation time was 33 (11-50) months. Two patients, both after plate osteosynthesis, had to be reoperated because of functional deficits due to adhesions. In both a tenolysis and removal of the plate was performed. The functional result was excellent in 20 of 25 patients treated by Kirschner wires, in seven of the eight in the screw-fixation group and in 13 of the 19 patients treated by plate ostheosynthesis (TAM > 240°); the result was judged fair in 1 after plate osteosynthesis (TAM 215°). The remaining 11 patients showed a good outcome with a TAM between 220° and 239°. These favourable results remained subjectively stable at the end of the observation period, when all patients could be contacted by phone.Osteosynthesis by kirschner wires, screws and plates for closed extraarticular fractures of the proximal phalanx of the long fingers gives good to excellent results with few complications. PMID:22382904

Egloff, C; Sproedt, J; Jandali, A R

2012-03-01

345

Percutaneous Stabilization of Impending Pathological Fracture of the Proximal Femur  

SciTech Connect

Objective: Percutaneous osteosynthesis plus cementoplasty (POPC) is a minimally invasive technique that has never been reported before and that we have prospectively evaluated for patients with impending pathological fracture of the proximal femur. Methods: We performed POPC in 12 patients (3 males, 9 females) with metastasis of the proximal femur with a high risk of fracture (Mirels' score {>=}8) between February 2010 and July 2011. Patients were not candidates for standard surgical stabilization. We analyzed the feasibility, duration, and complication of the procedure, the risk of fracture, the decrease in pain (Visual Analog Scale, VAS), and length of stay in hospital. Data were prospectively collected in all patients. Results: The mean Mirels' score was 9.8 {+-} 1.2 (range, 8-11). The technical success was 100%. POPC was performed under general anesthesia (n = 6) or conscious sedation (n = 6). The mean duration was 110 {+-} 43 (range, 60-180) minutes. All patients stood up and walked the second day after the procedure. The average length of stay in the hospital was 4 {+-} 1.6 (range, 2-7) days. We experienced two hematomas in two patients and no thromboembolic complication. For symptomatic patients (n = 8), VAS decreased from 6.5/10 (range, 2-9) before treatment to 1/10 (range, 0-3) 1 month after. No fracture occurred after a median follow-up of 145 (range, 12-608) days. Conclusions: POPC for impending pathological fracture of the proximal femur seems to be a promising alternative for cancer patients who are not candidates for surgical stabilization. Further studies are required to confirm this preliminary experience.

Deschamps, Frederic, E-mail: frederic.deschamps@igr.fr; Farouil, Geoffroy, E-mail: g.farouil@gmail.com; Hakime, Antoine, E-mail: thakime@yahoo.com; Teriitehau, Christophe, E-mail: cteriitehau@me.com; Barah, Ali, E-mail: ali.barah@gmail.com; Baere, Thierry de, E-mail: debaere@igr.fr [Institut Gustave Roussy, Interventional Radiology Department (France)

2012-12-15

346

Rapid population growth and environmental degradation: ultimate versus proximate factors.  

PubMed

This philosophical review of 2 arguments about responsibility for and solutions to environmental degradation concludes that both sides are correct: the ultimate and the proximal causes. Ultimate causes of pollution are defined as the technology responsible for a given type of pollution, such as burning fossil fuel; proximate causes are defined as situation-specific factors confounding the problem, such as population density or rate of growth. Commoner and others argue that developed countries with low or negative population growth rates are responsible for 80% of world pollution, primarily in polluting technologies such as automobiles, power generation, plastics, pesticides, toxic wastes, garbage, warfaring, and nuclear weapons wastes. Distortionary policies also contribute; examples are agricultural trade protection, land mismanagement, urban bias in expenditures, and institutional rigidity., Poor nations are responsible for very little pollution because poverty allows little waste or expenditures for polluting, synthetic technologies. The proximal causes of pollution include numbers and rate of growth of populations responsible for the pollution. Since change in the ultimate cause of pollution remains out of reach, altering the numbers of polluters can make a difference. Predictions are made for proportions of the world's total waste production, assuming current 1.6 tons/capita for developed countries and 0.17 tons/capita for developing countries. If developing countries grow at current rates and become more wealthy, they will be emitting half the world's waste by 2025. ON the other hand, unsustainable population growth goes along with inadequate investment in human capital: education, health, employment, infrastructure. The solution is to improve farming technologies in the 117 non-self-sufficient countries, fund development in the most unsustainable enclaves of growing countries, break institutionalized socio-political rigidity in these enclaves, and focus on educating and empowering women in these enclaves. Women are in charge of birth spacing and all aspects of management of energy, food, water and the local environment, more so than men, in most countries. PMID:12284190

Shaw, R P

1989-01-01

347

Does tamsulosin change the management of proximally located ureteral stones?  

PubMed

The objective of this study is to assess the efficacy of an alpha-1 adrenergic receptor blocking agent on the spontaneous passage of proximal ureteral calculi < or =10 mm. 92 patients having single radio-opaque proximal ureteral stone < or =10 mm were randomized into two groups. Group 1 patients (n = 50) were followed with classical conservative approach and patients in Group 2 (n = 42) additionally received tamsulosin, 0.4 mg/day during 4 weeks follow-up. The stone passage rates, stone expulsion time, VAS score, change in colic episodes, and hospital re-admission rates for colicky pain were compared. The patients were furthermore stratified according to stone diameters <5 and 5-10 mm. The data of these subgroups were also compared. Stone expulsion rates showed statistically significant difference between tamsulosin receivers and non-receivers (35.7 vs 30%, p = 0.04). Time to stone expulsion period was also shortened in those receiving tamsulosin (8.4 +/- 3.3 vs 11.6 +/- 4.1 days, p = 0.015). Likewise, the mean VAS score and renal colic episodes during follow-up period were significantly diminished in Group 2 patients (4.5 +/- 2.3 vs 8.8 +/- 2.9, p < 0.01 and 66.6 vs 36%, p = 0.001, respectively). Among the stones <5 mm, tamsulosin receiving patients had higher spontaneous passage rate (71.4 vs 50%, p < 0.001). The prominent effect of tamsulosin on the 5-10 mm stones was the relocation of the stones to a more distal part of ureter (39.3 vs 18.7%, p = 0.001). Administration of tamsulosin in the medical management of proximal ureteral calculi can facilitate the spontaneous passage rate in the stone <5 mm and the relocation of the stones between 5 and 10 mm to more distal part of the ureter. PMID:20182703

Yencilek, Faruk; Erturhan, Sakip; Canguven, Onder; Koyuncu, Hakan; Erol, Bulent; Sarica, Kemal

2010-02-25

348

Proximity effects and nonequilibrium superconductivity in transition-edge sensors  

NASA Astrophysics Data System (ADS)

We have recently shown that normal-metal/superconductor (N/S) bilayer superconducting transition-edge sensors (TESs) exhibit weak-link behavior. Here, we extend our understanding to include TESs with added noise-mitigating normal-metal structures (N structures). We find that TESs with added Au structures also exhibit weak-link behavior as evidenced by the exponential temperature dependence of the critical current and Josephson-like oscillations of the critical current with applied magnetic field. We explain our results in terms of an effect converse to the longitudinal proximity effect (LoPE), the lateral inverse proximity effect (LaiPE), for which the order parameter in the N/S bilayer is reduced due to the neighboring N structures. Resistance and critical current measurements are presented as a function of temperature and magnetic field taken on square Mo/Au bilayer TESs with lengths ranging from 8 to 130 ?m with and without added N structures. We observe the inverse proximity effect on the bilayer over in-plane distances many tens of microns and find the transition shifts to lower temperatures scale approximately as the inverse square of the in-plane N-structure separation distance, without appreciable broadening of the transition width. We also present evidence for nonequilbrium superconductivity and estimate a quasiparticle lifetime of 1.8×10-10 s for the bilayer. The LoPE model is also used to explain the increased conductivity at temperatures above the bilayer’s steep resistive transition.

Sadleir, John E.; Smith, Stephen J.; Robinson, Ian K.; Finkbeiner, Fred M.; Chervenak, James A.; Bandler, Simon R.; Eckart, Megan E.; Kilbourne, Caroline A.

2011-11-01

349

Perceptual organization by proximity and similarity in schizophrenia  

PubMed Central

Perceptual organization represents a basic and essential function that occurs at an intermediate level of visual processing. Much of the previous research on perceptual organization in schizophrenia employed indirect measurements, or included factors beyond sensory processing. The aims of the present study were to determine the integrity of perceptual organization in schizophrenia, as well as to determine the stimulus duration necessary to perform perceptual organization. Psychophysical measurements were compared between patients with schizophrenia and matched control subjects. Participants viewed dot patterns briefly presented on a computer monitor, and indicated whether stimuli appeared grouped as vertical or horizontal lines. Grouping was based upon either relative proximity or similarity in color. Across trials, relative proximity or color similarity was progressively reduced until stimuli became bistable (perceived as either of two patterns of grouping), establishing the grouping threshold. In separate conditions, stimuli were immediately followed by a mask to limit processing. Stimulus duration was progressively reduced until stimuli became bi-stable, establishing the critical stimulus duration (CSD). Schizophrenia patients demonstrated elevated grouping thresholds for grouping by proximity as well as color similarity. In addition, CSD was significantly extended for the schizophrenia group, with a nearly four-fold increase in duration of processing. These results provide direct evidence of impairment in schizophrenia for perceptual organization based upon spatial relationships and feature similarity, and suggest deficits in low-level perceptual organization processes. Although this study did not directly investigate the physiological correlates underlying perceptual impairments, these results are consistent with a theory of impaired lateral connections within visual cortical areas in schizophrenia.

Kurylo, Daniel D.; Pasternak, Roey; Silipo, Gail; Javitt, Daniel C.; Butler, Pamela D.

2007-01-01

350

The impact of quasiparticle tunnel injection on the proximity effect in Pb/Sn sandwich  

NASA Astrophysics Data System (ADS)

The proximity effect in Pb/Sn sandwich under the impact of quasiparticle tunnel injection has been studied. The estimation of the ? and ?BN proximity effect parameters has been made; the dependence of the ? and ?BN parameters on the Sn thickness has been built. It has been shown by studying the current-voltage characteristics of the double-barrier tunnel junction with a Pb/Sn intermediate proximity electrode that an increase of the ?m parameter of the strength of the proximity effect occurs as a result of quasiparticle tunnel injection into the Pb/Sn proximity electrode.

Rudenko, E. M.; Dubyna, D. S.; Krakovny, A. A.

2013-05-01

351

Pathology Case Study: Pain in Left Proximal Medial Thigh  

NSDL National Science Digital Library

This is a skeletal and soft tissue pathology case study presented by the University of Pittsburgh Department of Pathology in which a 9-year-old girl has left proximal medial thigh pain. Visitors are given both the microscopic and gross descriptions, including images, and are given the opportunity to diagnose the patient. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose. It is also a helpful site for educators to use to introduce or test student learning in skeletal and soft tissue pathology.

Dickman, Paul S.; Cohen, Lance; Parizhskaya, Maria

2007-10-10

352

Proximity effect and multiple Andreev reflections in gold atomic contacts.  

PubMed

We investigate the electronic transport properties of gold point contacts with superconducting aluminum leads. The modifications induced by the proximity effect in the quasiparticle density of states at the contact region are measured by tunnel spectroscopy. The theory of transport through multiple Andreev reflections is extended to incorporate these effects and used to determine the number and transmission coefficients of the conduction channels in the contact regime. We find that the smallest contacts, formed by one gold atom between the electrodes, contribute one single channel to the transport with variable transmission T between 0.1 and 1. PMID:11177812

Scheer, E; Belzig, W; Naveh, Y; Devoret, M H; Esteve, D; Urbina, C

2001-01-01

353

Proximal Humeral Fractures: A Review of Current Concepts  

PubMed Central

The majority of proximal humerus fractures are sustained via low energy falls in the elderly population. These patients can attain an acceptable level of function via non-operative treatment. There is yet to be a clear consensus on treatment options suitable for those that fall outside of this majority group. Open reduction internal fixation, intra medullary nailing and arthroplasty surgery have all been used to varying effects. Good results are achievable if complications such as mal-union, non-union and avascular necrosis can be avoided. This review aims to clarify the options available to the current day trauma surgeon.

Widnall, James C.; Dheerendra, Sujay K.; Malal, Joby Jacob George; Waseem, Mohammed

2013-01-01

354

[Reconstruction of the proximal femur with the MUTARS® system].  

PubMed

In the proximal femur a modular tumor prosthesis can be used today for reconstruction after resection of primary malignant bone tumors, metastatic lesions, and in revision surgery. The MUTARS® Münster system offers a high modularity and the possibility of combining it with the hip and knee revision system. Technical innovations, like hexagonal press fit bone anchorage, fine adjustment of rotation, silver coating of the surface of the prosthesis, and functional reconstruction with the help of a Trevira tube, guarantee a very good long-term survival of the prostheses and protection against the main complications such as aseptic loosening, deep infection, and instability. PMID:20844863

Winkelmann, W

2010-10-01

355

Proximity effect thermometer for local temperature measurements on mesoscopic samples.  

SciTech Connect

Using the strong temperature-dependent resistance of a normal metal wire in proximity to a superconductor, we have been able to measure the local temperature of electrons heated by flowing a direct-current (dc) in a metallic wire to within a few tens of millikelvin at low temperatures. By placing two such thermometers at different parts of a sample, we have been able to measure the temperature difference induced by a dc flowing in the samples. This technique may provide a flexible means of making quantitative thermal and thermoelectric measurements on mesoscopic metallic samples.

Aumentado, J.; Eom, J.; Chandrasekhar, V.; Baldo, P. M.; Rehn, L. E.; Materials Science Division; Northwestern Univ; Univ. of Chicago

1999-11-29

356

Fractures of the fibula proximal to the distal tibiofibular syndesmosis.  

PubMed

Study of thirty-six cases of fracture of the fibula at levels proximal to the distal tibiofibular syndesmosis established that there are three types, distinguished by the direction of the fracture line, which are produced by different mechanisms: supination-external rotation, pronation-abduction, and pronation-external rotation. Advanced lesions that were seen were severe injuries of the ankle which included rupture of the deltoid ligament or fracture of the medial malleolus and complete diastasis of the distal tibiofibular syndesmosis in addition to the fracture of the fibula. Surgical treatment is necessary in most advanced lesions. PMID:417086

Pankovich, A M

1978-03-01

357

Triplane fracture associated with a proximal third fibula fracture.  

PubMed

The case of a Maisonneuve fracture occurring in association with a triplane fracture in an adolescent wrestler is presented. In this combination of injuries, the deltoid ligament may be ruptured, and/or the medial malleolus fractured. If the proximal fibula fracture is not discovered, and the syndesmosis rupture is not treated, the resulting chronic talocrural instability may lead to chronic ankle pain and degenerative arthritis. The orthopedist should be aware of the possibility of a Maisonneuve fracture occurring in association with a triplane fracture, and should treat both injuries appropriately. PMID:8798988

Healy, W A; Starkweather, K D; Meyer, J; Teplitz, G A

1996-06-01

358

Radiotherapy for Soft Tissue Sarcoma of the Proximal Lower Extremity  

PubMed Central

Soft-tissue sarcoma (STS) is a histopathologically diverse group of tumors accounting for approximately 10,000 new malignancies in the US each year. The proximal lower extremity is the most common site for STS, accounting for approximately one-third of all cases. Coordinated multimodality management in the form of surgery and radiation is often critical to local control, limb preservation, and functional outcome. Based on a review of currently available Medline literature and professional experience, this paper provides an overview of the treatment of STS of the lower extremity with a particular focus on the modern role of radiotherapy.

Prendergast, Brendan; Fiveash, John B.; Gibbs, C. Parker; Scarborough, Mark T.; Indelicato, Daniel J.

2010-01-01

359

Pseudocontractions in the intermediate sense: Fixed and best proximity points  

NASA Astrophysics Data System (ADS)

This paper studies a general contractive condition for a class of two-cyclic self-maps on the union of a finite number of subsets of a metric space which are allowed to have a finite number of successive images in the same subsets of its domain. If the space is uniformly convex and the subsets are non-empty, closed and convex then all the iterated sequences are proved to converge to a unique closed limiting finite sequence. Such a sequence contains the best proximity points of adjacent subsets which coincide with a unique fixed point if all such subsets intersect.

De la Sen, Manuel

2013-09-01

360

Managing bone deficiency and nonunions of the proximal femur.  

PubMed

Revision surgery of the proximal femur with bone loss secondary to failed cephalomedullary nails is problematic and becoming more prevalent as their use grows. This article presents a technique of deformity correction, bone graft techniques that reconstitute residual defects, and definitive fixation using load-sharing devices that provide immediate stability for bone healing and early rehabilitation. Preoperative planning and the potential advantages and disadvantages of newer fixed-angled plates versus established implants are discussed. With proper planning, surgical execution with proved techniques, augmented by the addition of newer graft harvesting techniques, anatomic restoration, and bone reconstitution with healing, has invariably been the result. PMID:19931059

Perry, John J; Winter, Brent; Mast, Jeffrey W

2010-01-01

361

Proximity-induced unconventional superconductivity in topological insulators  

NASA Astrophysics Data System (ADS)

We study and classify the proximity-induced superconducting pairing in a topological insulator (TI)-superconductor (SC) hybrid structure for SCs with different symmetries. The Dirac surface state gives a coupling between spin-singlet and spin-triplet pairing amplitudes as well as pairing that is odd in frequency for p-wave SCs. We also find that all SCs induce pairing that is odd in both frequency and orbital (band) index, with oddness in frequency and orbital index being completely interchangeable. The different induced pairing amplitudes significantly modify the density of states in the TI surface layer.

Black-Schaffer, Annica M.; Balatsky, Alexander V.

2013-06-01

362

Proximity effects in a topological-insulator/Mott-insulator heterostructure  

NASA Astrophysics Data System (ADS)

We investigate proximity effects in a correlated heterostructure of a two-dimensional Mott insulator (MI) and a topological insulator (TI) by employing inhomogeneous dynamical mean-field theory. We show that the edge state of the TI induces strongly renormalized midgap states inside the MI region, which still have a remnant of the helical energy spectrum. The penetration of low-energy electrons, which is controlled by the interface tunneling V, largely enhances the electron mass inside the MI and also splits a single Dirac cone at edge sites into the spatially separated two Dirac cones in the strong V region.

Ueda, Suguru; Kawakami, Norio; Sigrist, Manfred

2013-04-01

363

Proximal Splenic Artery Embolization In Blunt Splenic Trauma  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Background:\\u000a   Proximal embolization of the splenic artery (PSAE) has recently been reported for traumatic splenic injury. The suggested\\u000a mechanism of action entails a decrease in the splenic blood pressure without ischemia due to collateral blood supply. The\\u000a main complications of selective embolization are continuous bleeding, splenic infarcts and splenic abscesses. The main complications\\u000a of observation alone are continuous bleeding

Osnat Zmora; Yitzhak Kori; David Samuels; Ada Kessler; Carl I. Schulman; Joseph M. Klausner; Dror Soffer

2009-01-01

364

Two K(+)-selective conductances in single proximal tubule cells isolated from frog kidney are regulated by ATP.  

PubMed Central

1. The whole-cell and single channel patch clamp techniques were used to identify K(+)-selective conductances in single proximal tubule cells isolated from frog kidney and to examine their ATP sensitivity. Whole-cell currents were inhibited by the K+ channel inhibitors Ba2+ and quinidine in a dose-dependent manner. Addition of Ba2+ alone, quinidine alone, or both inhibitors together revealed two separate conductances, one of which was blocked by both Ba2+ and quinidine (GBa)1, the other being sensitive to quinidine alone (Gquin). 2. With Na(+)-containing Ringer solution in the bath and K(+)-containing Ringer solution in the pipette, both currents were selective for K+ over Na+. The K+ : Na+ selectivity ratio of GBa was around 50:1, while that of Gquin was 4:1. In symmetrical KCl solutions GBa showed inward rectification, while Gquin demonstrated outward rectification. 3. In the absence of pipette ATP, both GBa and Gquin ran down over 10 min. However, when 2 mM ATP was included in the pipette GBa increased, while Gquin remained unchanged. 4. Single channel studies demonstrated that a basolateral K+ channel shared several of the characteristics of GBa. It was inhibited by both Ba2+ and quinidine, underwent run-down in excised patches in the absence of ATP, and was activated by ATP. 5. We conclude that cells of the frog proximal tubule contain at least two distinct K(+)-selective conductances, both of which are regulated by ATP, and which may be involved in pump-leak coupling. Images Figure 6

Robson, L; Hunter, M

1997-01-01

365

Video microscopy of intracellular pH in primary cultures of rabbit proximal and early distal tubules.  

PubMed

The purpose of this study was to investigate intracytoplasmic pH (pHi) regulation in primary cultures of proximal (PCT) and distal bright (DCTb) convoluted tubules. PCT and DCTb segments were microdissected from rabbit kidney cortex and cultured in a hormonally defined medium. The cultured epithelia were grown on semi-transparent permeable supports. The pHi was determined by video microscopy and digital image processing using 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF) and measuring the ratio of BCECF fluorescence excited by two successive wavelengths (490 nm and 450 nm). Resting pHi values, determined in bicarbonate-free medium (extracellular pH: 7.40), were 7.25 +/- 0.02 (n = 23) and 7.17 +/- 0.04 (n = 30) for cultured PCT and DCTb respectively. After the acid-loading procedure, cultured proximal cells recovered their pHi by means of the classic Na+/H+ antiporter, sensitive to amiloride and located in the apical membrane only. In cultured DCTb part of the pHi recovery was mediated by a Na+/H+ exchange present in the basolateral side. Moreover, at physiological initial pHi values, chloride removal from the apical solution caused the pHi to increase in the presence of bicarbonate. In acidified cultured DCTb cells, a partial pHi recovery was induced in sodium-free media by 15 mM HCO(-3) in the presence of an outward chloride gradient. This pHi change was completely abolished by 4,4'-diisothiocyanostilbene 2,2'-disulfonic acid (1 mM). These data suggest that DCTb cells possess in apical anion/base exchanger that resembles the Na(+)-independent Cl-/HCO(-3) exchanger. PMID:2166273

Bidet, M; Tauc, M; Koechlin, N; Poujeol, P

1990-05-01

366

Cell cycle-dependent and kinase-specific regulation of the apical Na/H exchanger and the Na,K-ATPase in the kidney cell line LLC-PK1 by calcitonin.  

PubMed Central

Calcitonin (CT), which regulates serum calcium through its actions in bone and the kidney tubule, also has a potent natriuretic effect in vivo. Na reabsorption in the proximal kidney tubule is mostly dependent on the activity of the Na,K-ATPase and the apical Na/H exchanger. We have previously shown that CT regulates the activity of the Na,K-ATPase in the proximal kidney tubule cell line LLC-PK1 in a cell cycle-dependent manner. We report here that, in the same cells, CT also regulates the Na/H exchanger through a cell cycle-specific activation of the Ca/calmodulin-dependent protein kinase II. In G2 phase, no changes in ethylisopropyl amiloride-sensitive 22Na uptake is observed, despite an increase in cAMP. In contrast, the hormone inhibits the apical exchanger when the cells are in S phase, resulting in an 80% inhibition of 22Na uptake. These results demonstrate that CT affects the activity of the two major proximal tubule Na transport systems and may help clarify the mechanisms by which CT regulates Na+ reabsorption. Images

Chakraborty, M; Chatterjee, D; Gorelick, F S; Baron, R

1994-01-01

367

Proximal myotonic dystrophy—a family with autosomal dominant muscular dystrophy, cataracts, hearing loss and hypogonadism: heterogeneity of proximal myotonic syndromes?  

Microsoft Academic Search

We describe a family with an autosomal dominant, multisystem disorder, consisting of late-onset proximal muscular dystrophy, electrophysiological myotonia, cataracts, late-onset deafness and male hypogonadism. Four patients were available for clinical examinations. Examination of asymptomatic family members revealed another patient with bilateral cataracts but without definite muscle disorder. Five deceased members of the family had proximal muscle weakness, reportedly or confirmed

Bjarne Udd; Ralf Krahe; Carina Wallgren-Pettersson; Björn Falck; Hannu Kalimo

1997-01-01

368

Surgical technique for repair of acute proximal hamstring tears.  

PubMed

The surgical technique for repair of acute proximal hamstring tears is relatively recent. Installation of the patient is critical. The approach is either vertical under the gluteal fold in case of a complete tear with tendon retraction of more than 6 cm, or horizontal in the gluteal fold for retraction of less than 6 cm or for partial tears. After identification and neurolysis of the sciatic nerve, transosseous tendon reinsertion is performed with three or four metal or resorbable suture anchors. A rigid brace keeping the leg at 30° of flexion is worn for few days, then replaced by an articulated knee brace for 45 days, which limits extension but allows full flexion. Rehabilitation is begun early. Thirty-four patients underwent surgery for acute proximal hamstring tear and received this treatment. All of the athletic patients were able to return to their pre-injury activities after a mean 5.7 ± 1.6 months (2.3-9.3 months). PMID:22926295

Lefevre, N; Bohu, Y; Klouche, S; Herman, S

2012-08-25

369

Optimal proximity correction: application for flash memory design  

NASA Astrophysics Data System (ADS)

Proximity Correction is the technology for which the most of IC manufacturers are committed already. The final intended result of correction is affected by many factors other than the optical characteristics of the mask-stepper system, such as photoresist exposure, post-exposure bake and development parameters, etch selectivity and anisotropy, and underlying topography. The most advanced industry and research groups already reported immediate need to consider wafer topography as one of the major components during a Proximity Correction procedure. In the present work we are discussing the corners rounding effect (which eventually cause electrical leakage) observed for the elements of Poly2 layer for a Flash Memory Design. It was found that the rounding originated by three- dimensional effects due to variation of photoresist thickness resulting from the non-planar substrate. Our major goal was to understand the reasons and correct corner rounding. As a result of this work highly effective layout correction methodology was demonstrated and manufacturable Depth Of Focus was achieved. Another purpose of the work was to demonstrate complete integration flow for a Flash Memory Design based on photolithography; deposition/etch; ion implantation/oxidation/diffusion; and device simulators.

Chen, Y. G.; Huang, D. L.; Sung, K. T.; Chiang, J. J.; Yu, M.; Teng, F.; Chu, Lung; Rey, Juan C.; Bernard, Douglas A.; Li, Jiangwei; Li, Junling; Moroz, V.; Boksha, Victor V.

1998-06-01

370

Group Problem Solving as a Zone of Proximal Development activity  

NASA Astrophysics Data System (ADS)

Vygotsky described learning as a process, intertwined with development, which is strongly influenced by social interactions with others that are at differing developmental stages.i These interactions create a Zone of Proximal Development for each member of the interaction. Vygotsky’s notion of social constructivism is not only a theory of learning, but also of development. While teaching introductory physics in an interactive format, I have found manifestations of Vygotsky’s theory in my classroom. The source of evidence is a paired problem solution. A standard mechanics problem was solved by students in two classes as a homework assignment. Students handed in the homework and then solved the same problem in small groups. The solutions to both the group and individual problem were assessed by multiple reviewers. In many cases the group score was the same as the highest individual score in the group, but in some cases, the group score was higher than any individual score. For this poster, I will analyze the individual and group scores and focus on three groups solutions and video that provide evidence of learning through membership in a Zone of Proximal Development. Endnotes i L. Vygotsky -Mind and society: The development of higher mental processes. Cambridge, MA: Harvard University Press. (1978).

Brewe, Eric

2006-12-01

371

Proximity to pollution sources and risk of amphibian limb malformation.  

PubMed

The cause of limb deformities in wild amphibian populations remains unclear, even though the apparent increase in prevalence of this condition may have implications for human health. Few studies have simultaneously assessed the effect of multiple exposures on the risk of limb deformities. In a cross-sectional survey of 5,264 hylid and ranid metamorphs in 42 Vermont wetlands, we assessed independent risk factors for nontraumatic limb malformation. The rate of nontraumatic limb malformation varied by location from 0 to 10.2%. Analysis of a subsample did not demonstrate any evidence of infection with the parasite Ribeiroia. We used geographic information system (GIS) land-use/land-cover data to validate field observations of land use in the proximity of study wetlands. In a multiple logistic regression model that included land use as well as developmental stage, genus, and water-quality measures, proximity to agricultural land use was associated with an increased risk of limb malformation (odds ratio = 2.26; 95% confidence interval, 1.42-3.58; p < 0.001). The overall discriminant power of the statistical model was high (C = 0.79). These findings from one of the largest systematic surveys to date provide support for the role of chemical toxicants in the development of amphibian limb malformation and demonstrate the value of an epidemiologic approach to this problem. PMID:16263502

Taylor, Brynn; Skelly, David; Demarchis, Livia K; Slade, Martin D; Galusha, Deron; Rabinowitz, Peter M

2005-11-01

372

Promoter-proximal polyadenylation sites reduce transcription activity.  

PubMed

Gene expression relies on the functional communication between mRNA processing and transcription. We previously described the negative impact of a point-mutated splice donor (SD) site on transcription. Here we demonstrate that this mutation activates an upstream cryptic polyadenylation (CpA) site, which in turn causes reduced transcription. Functional depletion of U1 snRNP in the context of the wild-type SD triggers the same CpA event accompanied by decreased RNA levels. Thus, in accordance with recent findings, U1 snRNP can shield premature pA sites. The negative impact of unshielded pA sites on transcription requires promoter proximity, as demonstrated using artificial constructs and supported by a genome-wide data set. Importantly, transcription down-regulation can be recapitulated in a gene context devoid of splice sites by placing a functional bona fide pA site/transcription terminator within ~500 base pairs of the promoter. In contrast, promoter-proximal positioning of a pA site-independent histone gene terminator supports high transcription levels. We propose that optimal communication between a pA site-dependent gene terminator and its promoter critically depends on gene length and that short RNA polymerase II-transcribed genes use specialized termination mechanisms to maintain high transcription levels. PMID:23028143

Andersen, Pia K; Lykke-Andersen, Søren; Jensen, Torben Heick

2012-10-01

373

Digital Image Enhancement Improves Diagnosis of Nondisplaced Proximal Femur Fractures  

PubMed Central

Today most emergency room radiographs are computerized, making digital image enhancement a natural advancement to improve fracture diagnosis. We compared the diagnosis of nondisplaced proximal femur fractures using four different image enhancement methods using standard DICOM (Digital Imaging and Communications in Medicine) after window-leveling optimization. Twenty-nine orthopaedic residents and specialists reviewed 28 pelvic images consisting of 25 occult proximal femur fractures and three images with no fracture, using four different image filters and the original DICOM image. For intertrochanteric fractures, the Retinex filter outperforms the other filters and the original image with a correct fracture type diagnosis rate of 50.6%. The Retinex filter also performs well for diagnosis of other fracture types. The Retinex filter had an interobserver agreement index of 53.5%, higher than the other filters. Sensitivity of fracture diagnosis increased to 85.2% when the Retinex filter was combined with the standard DICOM image. Correct fracture type diagnosis per minute for the Retinex filter was 1.43, outperforming the other filters. The Retinex filter may become a valuable tool in clinical settings for diagnosing fractures. Level of Evidence: Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Herman, Amir; Nathaniel, Ram; Rappaport, Dan; Chechik, Aharon

2008-01-01

374

Lung cancer mortality and residential proximity to industry.  

PubMed Central

A potential causal relationship has been suggested by other studies between air pollution and lung cancer. To attempt to define the risk of lung cancer associated with residential proximity to industry by type in Louisiana, lung cancer deaths occurring between 1960 and 1975 in residents of 20 parishes were compared to controls matched on age, sex, year of death and parish of residence. The comparisons were limited to cases (N = 1418) and controls (N = 1429) with known length of exposure to and residing within 0.99 mile (exposed and 1.0 to 3.0 miles (unexposed) radius of an industry type. Of the 13 industry types evaluated, the petroleum and chemical industries showed the highest consistent elevations in risk associated with closeness of residence to industry, whereas possible risks shown for food, grain, canning, and paper industries are less defined. For the petroleum industry, the risk was demonstrated in the group with 10 or more years of residential exposure to the industry in question. For the chemical industry, the residential risk was found in people employed in low risk occupations, who were exposed to large individual industries and was independent of length of exposure as determined for less or more than ten years, (RR = 4.5). The results suggest that residential proximity to petrochemical industries may make a contribution to the lung cancer mortality in Louisiana.

Gottlieb, M S; Shear, C L; Seale, D B

1982-01-01

375

Riboflavin transport by isolated perfused rabbit renal proximal tubules.  

PubMed

Rabbit renal proximal tubular transport of riboflavin (RF) was examined by using the in vitro isolated tubule perfusion technique. We found that proximal tubules actively reabsorbed (J(lb)) and secreted (J(bl)) RF. At 0.1 microM RF concentration, J(bl) was significantly higher than J(lb), resulting in a net secretion. This net secretion of RF was decreased at 0.01 microM RF concentration and increased at 1 microM RF concentration. Both J(lb) and J(bl) were inhibited by lowering temperature or by adding iodoacetate, a metabolic inhibitor, and lumichrome, an RF analog, suggesting the involvement of carrier-mediated transport mechanisms. J(bl) was inhibited by probenecid, an anion transport inhibitor, and by para-aminohippuric acid, an organic anion, suggesting the relevance of RF secretion to renal organic anion transport. J(bl) was also inhibited by alkaline pH (8.0) and by the calmodulin inhibitor trifluoperazine, indicating the influence of pH and Ca(2+)/calmodulin-dependent pathway on RF secretion. Finally, we found that addition of chlorpromazine, a phenothiazine derivative, inhibited both J(lb) and J(bl), raising the concern about the nutritional status in patients receiving such a type of medication. PMID:11078692

Yanagawa, N; Shih, R N; Jo, O D; Said, H M

2000-12-01

376

Autophagy in proximal tubules protects against acute kidney injury  

PubMed Central

Autophagy is induced in renal tubular cells during acute kidney injury, however, whether this is protective or injurious remains controversial. We address this question by pharmacologic and genetic blockade of autophagy using mouse models of cisplatin- and ischemia-reperfusion induced acute kidney injury. Chloroquine, a pharmacological inhibitor of autophagy, blocked autophagic flux and enhanced acute kidney injury in both models. Rapamycin, however, activated autophagy and protected against cisplatin-induced acute kidney injury. We also established a renal proximal tubule-specific autophagy-related gene 7 knockout mouse model shown to be defective in both basal and cisplatin induced autophagy in kidneys. Compared with wild-type littermates, these knockout mice were markedly more sensitive to cisplatin-induced acute kidney injury as indicated by renal functional loss, tissue damage, and apoptosis. Mechanistically, these knockout mice had heightened activation of p53 and c-Jun N terminal kinase, signaling pathways contributing to cisplatin acute kidney injury. Proximal tubular cells isolated from the knockout mice were more sensitive to cisplatin-induced apoptosis than cells from wild-type mice. In addition, the knockout mice were more sensitive to renal ischemia-reperfusion injury than their wild-type littermates. Thus, our results establish a renoprotective role of tubular cell autophagy in acute kidney injury where it may interfere with cell killing mechanisms.

Jiang, Man; Wei, Qing-qing; Dong, Guie; Komatsu, Masaaki; Su, Yunchao; Dong, Zheng

2012-01-01

377

Vision-based Proximity Detection in Retinal Surgery  

PubMed Central

In retinal surgery, surgeons face difficulties such as indirect visualization of surgical targets, physiological tremor and lack of tactile feedback, which increase the risk of retinal damage caused by incorrect surgical gestures. In this context, intra-ocular proximity sensing has the potential to overcome current technical limitations and increase surgical safety. In this paper we present a system for detecting unintentional collisions between surgical tools and the retina using the visual feedback provided by the opthalmic stereo microscope. Using stereo images, proximity between surgical tools and the retinal surface can be detected when their relative stereo disparity is small. For this purpose, we developed a system comprised of two modules. The first is a module for tracking the surgical tool position on both stereo images. The second is a disparity tracking module for estimating a stereo disparity map of the retinal surface. Both modules were specially tailored for coping with the challenging visualization conditions in retinal surgery. The potential clinical value of the proposed method is demonstrated by extensive testing using a silicon phantom eye and recorded rabbit in vivo data.

Richa, Rogerio; Balicki, Marcin; Sznitman, Raphael; Meisner, Eric; Taylor, Russell; Hager, Gregory

2012-01-01

378

Optical proximity correction using a transmittance-controlled mask (TCM)  

NASA Astrophysics Data System (ADS)

When small feature delineation is considered using existing exposure tools, special techniques might be needed such as phase shift mask, oblique illumination, top surface imaging, etc. When different types of patterns exist simultaneously or island patterns exist predominantly, optical proximity effect will become more important to be controlled. In this study, six different mask types were prepared and evaluated in view of a pattern fidelity and process latitude for 256 mega bit DRAM's storage node patterns. The masks used for this experiment were conventional transmission mask, serif patterned mask, square patterned Transmittance Controlled Mask (TCM), horizontally rectangular TCM, vertically rectangular TCM, and cross patterned TCM. The cross patterned TCM had three different transmittance on it and was evaluated also. In view of both pattern fidelity and process latitude, cross-TCM showed the best result. The vert-TCM also showed fairly good result. But the worst results always came from the conventional mask. From plane surface area point of view, once serif mask or TCMs are used, the areas always improved ranging from 120% to 145% at the best focus condition compared to the convention mask. There was not so much difference among three different transmittance in view of pattern fidelity and process latitude. As one of candidates for optical proximity correction, since small serif delineation on mask level is not easy for devices with small features such as 1 giga bit DRAM or beyond, TCM is more promising which has much bigger and easily writable gray area.

Han, Woo-Sung; Sohn, Chang-Jin; Kim, Yong-Beom; Kim, Kee-Ho; Kang, Ho-Young; Koh, Young-Bum; Lee, Moon-Yong

1995-05-01

379

Two Proximal Skin Electrodes -- A Respiration Rate Body Sensor  

PubMed Central

We propose a new body sensor for extracting the respiration rate based on the amplitude changes in the body surface potential differences between two proximal body electrodes. The sensor could be designed as a plaster-like reusable unit that can be easily fixed onto the surface of the body. It could be equipped either with a sufficiently large memory for storing the measured data or with a low-power radio system that can transmit the measured data to a gateway for further processing. We explore the influence of the sensor's position on the quality of the extracted results using multi-channel ECG measurements and considering all the pairs of two neighboring electrodes as potential respiration-rate sensors. The analysis of the clinical measurements, which also include reference thermistor-based respiration signals, shows that the proposed approach is a viable option for monitoring the respiration frequency and for a rough classification of breathing types. The obtained results were evaluated on a wireless prototype of a respiration body sensor. We indicate the best positions for the respiration body sensor and prove that a single sensor for body surface potential difference on proximal skin electrodes can be used for combined measurements of respiratory and cardiac activities.

Trobec, Roman; Rashkovska, Aleksandra; Avbelj, Viktor

2012-01-01

380

Cancer risk and residential proximity to cranberry cultivation in Massachusetts.  

PubMed Central

OBJECTIVES: This study evaluated the relationship between cancer risk and residential proximity to cranberry cultivation. METHODS: A population-based case-control study was conducted. Cases, diagnosed during 1983 through 1986 among residents of the Upper Cape Cod area of Massachusetts, involved incident cancers of the lung (n = 252), breast (n = 265), colon-rectum (n = 326), bladder (n = 63), kidney (n = 35), pancreas (n = 37), and brain (n = 37), along with leukemia (n = 35). Control subjects were randomly selected from among telephone subscribers (n = 184), Medicare beneficiaries (n = 464), and deceased individuals (n = 723). RESULTS: No meaningful increases in risk were seen for any of the cancer sites except for the brain. When latency was considered, subjects who had ever lived within 2600 ft (780 m) of a cranberry bog had a twofold increased risk of brain cancer overall (95% confidence interval [CI] = 0.8, 4.9) and a 6.7-fold increased risk of astrocytoma (95% CI = 1.6, 27.8). CONCLUSIONS: Residential proximity to cranberry bog cultivation was not associated with seven of the eight cancers investigated; however, an association was observed with brain cancer, particularly astrocytoma. Larger, more detailed studies are necessary to elucidate this relationship.

Aschengrau, A; Ozonoff, D; Coogan, P; Vezina, R; Heeren, T; Zhang, Y

1996-01-01

381

A proximal promoter domain containing a homeodomain-binding core motif interacts with multiple transcription factors, including HoxA5 and Phox2 proteins, and critically regulates cell type-specific transcription of the human norepinephrine transporter gene.  

PubMed

Expression of the norepinephrine transporter (NET), which mediates the reuptake of norepinephrine into presynaptic nerve terminals, is restricted to noradrenergic (NA) neurons. We have demonstrated previously that the 9.0 kb upstream sequences and the first intron residing in the 5' untranslated area are critical for high-level and NA cell-specific transcription. Here, using transient transfection assays, we show that 4.0 kb of the 5' upstream sequences contains sufficient genetic information to drive reporter gene expression in an NA cell type-specific manner. Three functional domains appear to be potentially important for the regulation of human NET (hNET) gene transcription: an upstream enhancer region at -4.0 to -3.1 kb, a proximal domain at -133 to -75 bp, and a middle silencer region between these two domains. DNase I footprinting analysis of the proximal promoter region shows that a subdomain at -128 to -80 bp is protected in a cell-specific manner. We provide evidence that multiple protein factors interact with the proximal promoter domain to critically regulate the transcriptional activity of the hNET gene. In the middle of this proximal subdomain resides a homeodomain (HD)-binding core motif, which interacts with HD factors, including Phox2a and HoxA5, in an NA-specific manner. Cotransfection analyses suggest that HoxA5 and Phox2a may transactivate the hNET gene promoter. Together with previous studies indicating direct activation of dopamine beta-hydroxylase transcription by Phox2a/2b, the present results support a model whereby Phox2 proteins may coordinately regulate the phenotypic specification of NA neurons by activating both NA biosynthetic and reuptake genes. PMID:11923423

Kim, Chun-Hyung; Hwang, Dong-Youn; Park, Jae-Joon; Kim, Kwang-Soo

2002-04-01

382

Analysis of Na+-D-glucose cotransporter and other renal brush border proteins in human urine  

Microsoft Academic Search

Analysis of Na+-D-glucose cotransporter and other renal brush border proteins in human urine. A sensitive quantitative radioimmunoassay is described by which different antigens in the urine can be assayed simultaneously. Urinary excretion of three proteins from proximal tubules was compared: 1) the Na+-D-glucose cotransporter from brush border membranes and subapical vesicles; 2) a kidney-specific hydrophobic Mr 400,000 polypeptide from intermicroviUar

Horst-Walter Birk; Stefan Piberhofer; Georg Schütterle; Winfried Haase; Jochem Kötting; Hermann Koepsell

1991-01-01

383

Regulation of reconstituted renal Na + \\/H + exchanger by calcium-dependent protein kinases  

Microsoft Academic Search

Summary Studies were performed to determine the effect of protein phosphorylation mediated by calcium-calmodulin-dependent multifunctional protein kinase II and calcium-phospholipid-dependent protein kinase on Na+\\/H+ exchange activity. Proteins from the apical membrane of the proximal tubule of the rabbit kidney were solubilized in octyl glucoside and incubated in phosphorylating solutions containing the protein kinase.22Na+ uptake was determined subsequently after reconstitution of

E. J. Weinman; W. P. Dubinsky; K. Fisher; D. Steplock; Q. Dinh; L. Chang; S. Shenolikar

1988-01-01

384

Dopamine inhibits Na\\/K-ATPase in single tubules and cultured cells from distal nephron  

Microsoft Academic Search

Dopamine decreases tubular sodium reabsorption, attributed in part to Na\\/K-ATPase inhibition in the proximal convoluted tubule (PCT). Because the final regulation of sodium excretion occurs in the collecting duct, where we have demonstrated specific dopamine DA1 binding sites, we examined the effects of dopamine, and of DA1 and DA2 receptor agonists on the Na\\/K pump in the microdissected rat cortical

Fumi Takemoto; Herbert T. Cohen; Takeo Satoh; Adrian I. Katz

1992-01-01

385

Large-scale phosphoproteomic analysis of membrane proteins in renal proximal and distal tubule  

PubMed Central

Recent advances in mass spectrometry (MS) have provided means for large-scale phosphoproteomic profiling of specific tissues. Here, we report results from large-scale tandem MS [liquid chromatography (LC)-MS/MS]-based phosphoproteomic profiling of biochemically isolated membranes from the renal cortex, with focus on transporters and regulatory proteins. Data sets were filtered (by target-decoy analysis) to limit false-positive identifications to <2%. A total of 7,125 unique nonphosphorylated and 743 unique phosphorylated peptides were identified. Among the phosphopeptides identified were sites on transporter proteins, i.e., solute carrier (Slc, n = 63), ATP-binding cassette (Abc, n = 4), and aquaporin (Aqp, n = 3) family proteins. Database searches reveal that a majority of the phosphorylation sites identified in transporter proteins were previously unreported. Most of the Slc family proteins are apical or basolateral transporters expressed in proximal tubule cells, including proteins known to mediate transport of glucose, amino acids, organic ions, and inorganic ions. In addition, we identified potentially important phosphorylation sites for transport proteins from distal nephron segments, including the bumetanide-sensitive Na-K-2Cl cotransporter (Slc12a1 or NKCC2) at Ser87, Thr101, and Ser126 and the thiazide-sensitive Na-Cl cotransporter (Slc12a3 or NCC) at Ser71 and Ser124. A subset of phosphorylation sites in regulatory proteins coincided with known functional motifs, suggesting specific regulatory roles. An online database from this study (http://dir.nhlbi.nih.gov/papers/lkem/rcmpd/) provides a resource for future studies of transporter regulation.

Feric, Marina; Zhao, Boyang; Hoffert, Jason D.; Pisitkun, Trairak

2011-01-01

386

The proximate, mineral, and toxicant compositions of four possible food security crops from southeastern Nigeria.  

PubMed

The proximate, nutritional, and antinutritional compositions of the raw, cooked, and roasted samples of four Nigerian indigenous seeds-Sphenostylis stenocarpa, Pentaclethra macrophylla, Mucuna flagellipes, and Citrullus colocynthis-were evaluated. Also estimated were zinc and divalent cation bioavailability of the seeds using millimolar ratios/kg dry weight of [calcium]/[phytate], [phytate]/[zinc], [calcium][phytate]/[Zn], and [phytate]/[total phosphorus]. The results obtained revealed that the seeds of P. macrophylla and C. colocynthis had high protein and lipid levels. All the seeds were also found to have high energy value and low moisture content. Mineral analysis showed the presence of Na, K, Ca, and Mg in appreciable quantities and Zn, I, Fe, and Se in minute quantities. Antinutritional analyses indicated the presence of traces of tannin, oxalate, phytate, saponin, and cyanide in the samples. The various processing techniques had significant (P???.05) effects on the measured parameters. The calculated [Ca][phytate]/[Zn] molar ratios revealed that these seeds had values above the critical level of 0.5?mL/kg, thus indicating reduced bioavailability of zinc. In view of the high nutrient contents, low antinutritional contents after processing, and their superabundance, these seeds could be cheap nutrient sources. The implications of these findings with regards to food security are enormous. PMID:20828321

Ojiako, Okey A; Ogbuji, Chiza A; Agha, Ngozi C; Onwuliri, Viola A

2010-10-01

387

Functional characterization of apical transporters expressed in rat proximal tubular cells (PTCs) in primary culture.  

PubMed

Since in vitro cell culture models often show altered apical transporter expression, they are not necessarily suitable for the analysis of renal transport processes. Therefore, we aimed here to investigate the usefulness of primary-cultured rat proximal tubular cells (PTCs) for this purpose. After isolation of renal cortical cells from rat kidneys, PTCs were enriched and the gene expression and function of apical transporters were analyzed by means of microarray, RT-PCR and uptake experiments. RT-PCR confirmed that the major apical transporters were expressed in rat PTCs. Na(+)-dependent uptake of ?-methyl-d-glucopyranoside (?MG), ergothioneine and carnitine by the PTCs suggests functional expression of Sglts, Octn1 and Octn2, respectively. Inhibition of pH-dependent glycylsarcosine uptake by low concentration of cephalexin, which is a ?-lactam antibiotics recognized by Pepts, indicates a predominant role of high affinity type Pept2, but not low affinity type Pept1, in the PTCs. Moreover, the permeability ratio of [(14)C]?MG (apical to basolateral/basolateral to apical) across PTCs was 4.3, suggesting that Sglt-mediated reabsorptive transport is characterized. In conclusion, our results indicate that rat PTCs in primary culture are found to be a promising in vitro model to evaluate reabsorption processes mediated at least by Sglts, Pept2, Octn1 and Octn2. PMID:21999946

Nakanishi, Takeo; Fukushi, Akimasa; Sato, Masanobu; Yoshifuji, Mayuko; Gose, Tomoka; Shirasaka, Yoshiyuki; Ohe, Kazuyo; Kobayashi, Masato; Kawai, Keiichi; Tamai, Ikumi

2011-10-28

388

Proximal microdeletions and microduplications of 1q21.1 contribute to variable abnormal phenotypes  

PubMed Central

Chromosomal band 1q21.1 can be divided into two distinct regions, proximal and distal, based on segmental duplications that mediate recurrent rearrangements. Microdeletions and microduplications of the distal region within 1q21.1, which are susceptibility factors for a variety of neurodevelopmental phenotypes, have been more extensively studied than proximal microdeletions and microduplications. Proximal microdeletions are known as a susceptibility factor for thrombocytopenia-absent radius (TAR) syndrome, but it is unclear if these proximal microdeletions have other phenotypic consequences. Therefore, to elucidate the clinical significance of rearrangements of the proximal 1q21.1 region, we evaluated the phenotypes in patients identified with 1q21.1 rearrangements after referral for clinical microarray testing. We report clinical information for 55 probands with copy number variations (CNVs) involving proximal 1q21.1: 22 microdeletions and 20 reciprocal microduplications limited to proximal 1q21.1 and 13 microdeletions that include both the proximal and distal regions. Six individuals with proximal microdeletions have TAR syndrome. Three individuals with proximal microdeletions and two individuals with larger microdeletions of proximal and distal 1q21.1 have a ‘partial' TAR phenotype. Furthermore, one subject with TAR syndrome has a smaller, atypical deletion, narrowing the critical deletion region for the syndrome. Otherwise, phenotypic features varied among individuals with these microdeletions and microduplications. The recurrent, proximal 1q21.1 microduplications are enriched in our population undergoing genetic testing compared with control populations. Therefore, CNVs in proximal 1q21.1 can be a contributing factor for the development of abnormal phenotypes in some carriers.

Rosenfeld, Jill A; Traylor, Ryan N; Schaefer, G Bradley; McPherson, Elizabeth W; Ballif, Blake C; Klopocki, Eva; Mundlos, Stefan; Shaffer, Lisa G; Aylsworth, Arthur S

2012-01-01

389

Simultaneous Mg, Ca, P, K, Na and Cl analysis in rat tubular fluid  

Microsoft Academic Search

The micropuncture recollection technique was used for further analysis of Mg, Ca, P, Na, Cl and K tubular handling during and after acute magnesium plasma loading in the rat. The concentrations of these different ion species in late proximal and early distal fluid samples, ureteral urine and plasma ultrafiltrates were measured using electron probe microanalysis.3H-inulin was used as glomerular indicator.

Christian Grimellec; Nicole Roinel; François Morel; P. Philippe; P. Malorey

1973-01-01

390

Spatial coordination in memrane proximal signaling in T-cells  

NASA Astrophysics Data System (ADS)

Membrane-proximal signaling initiates signaling networks of the T-cell which ultimately lead to the T-cell activation. Signal formation requires assembly of the several membrane proteins and successful cooperative interactions inside the complex. Diffusion and chemical reactions involved in the process are characterized by substantially different timescales. In this work we consider how the reaction-diffusion system described by the wide spectrum of timescales can be selective for the minute amounts of the signal (cognate peptide-MHC complex) over the large amounts of irrelevant targets (non-cognate peptide-MHC complex). Note that single distinction between relevant and irrelevant targets - the affinity to the T-cell receptor, is nonetheless sufficient to discriminate between two groups of targets. Moreover, proposed mechanism allows for signal cooperativity with non-cognate peptides amplifying the signal from cognate ones even though they can not signal by themselves. This kind of cooperativity has been observed in recent experiments.

Artyomov, Maxim N.; Lis, Mieszko; Chakraborty, Arup

2009-03-01

391

Fundamental Proximity Effects in Focused electron Beam Induced Deposition  

SciTech Connect

Fundamental proximity effects for electron beam induced deposition processes on nonflat surfaces were studied experimentally and via simulation. Two specific effects were elucidated and exploited to considerably increase the volumetric growth rate of this nanoscale direct write method: (1) increasing the scanning electron pitch to the scale of the lateral electron straggle increased the volumetric growth rate by 250% by enhancing the effective forward scattered, backscattered, and secondary electron coefficients as well as by strong recollection effects of adjacent features; and (2) strategic patterning sequences are introduced to reduce precursor depletion effects which increase volumetric growth rates by more than 90%, demonstrating the strong influence of patterning parameters on the final performance of this powerful direct write technique.

Plank, Harald [Graz University of Technology; Smith, Daryl [University of Tennessee, Knoxville (UTK); Haber, Thomas [Graz University of Technology; Rack, Philip D [ORNL; Hofer, Ferdinand [Graz University of Technology

2012-01-01

392

Fast optical proximity correction with timing optimization ready standard cells  

NASA Astrophysics Data System (ADS)

Resolution enhancement techniques (RET) such as optical proximity correction (OPC) has become an integral part of the fabrication of integrated circuits to maintain the edge placement integrity of the original circuit design. Conventional OPC schemes are usually shape driven and full chip based, resulting in unpredictability in electrical behavior and huge computational effort. To overcome these drawbacks, a new OPC methodology which is electrically driven and based on cell-wise optimization is proposed. Simulation results when compared to conventional OPC approaches in the literature demonstrate better timing accuracy with reduced mask cost. Depending of the circuit test-set, an average run-time improvement between 3 to 8 times is achieved for circuit size with 100 - 400 cells. Further improvements can be obtained by adopting a hybrid approach by only optimizing the timing performance of critical paths. For the hybrid approach, better timing accuracy can be achieved while incurring little penalty on mask cost.

Qu, Yifan; Heng, Chun Huat; Tay, Arthur; Lee, Tong Heng

2012-03-01

393

[The effect of proximal-selective vagotomy in gastroduodenal ulcer].  

PubMed

In a recently concluded prospective multicenter trial, pyloric (PU) and prepyloric (PPU) ulcers showed a significantly higher recurrence rate after proximal gastric vagotomy (PGV) without drainage than duodenal (DU) or gastric ulcers (GU). The secretory pattern of the PU and PPU cannot explain the failure of PGV. However, PU and PPU (and some GU) exhibit a distinct and probably irreversible alteration of the muscular layer at the pylorus and distal antrum. This could be one factor which helps to explain the failure of vagotomy alone in these ulcer types. To deal with this antropyloric distrophy, addition of drainage or antrectomy to PGV must be considered. A refined concept for surgical treatment of peptic ulcer is proposed. PMID:6740294

Muller, C; Martinoli, S; Allgöwer, M

1984-05-26

394

Factors affecting minority population proximity to hazardous facilities  

SciTech Connect

Disproportionate exposure of minority groups to environmental hazards has been attributed to ``environmental racism`` by some authors, without systematic investigation of the factors underlying this exposure pattern. This study examines regional differences in the proximity of African-Americans, Hispanics, Asians, and non-Hispanic Whites to a broad range of facility types and explores the effects of urban and income factors. A statistically significant inverse relationship is found between the percentage of non-Hispanic Whites and virtually all facility categories in all regions. Except for Hispanics in the South, all such associations for minority groups show a direct relationship, though some are nonsignificant. The geographic concentration of facilities is more closely tied to urbanization than to economic factors. Controlling for both urban and economic factors, minority population concentration is still a significant explanatory variable for some facility types in some regions. This finding is most consistent for African-Americans.

Nieves, L.A. [Argonne National Lab., IL (United States); Nieves, A.L. [Wheaton Coll., IL (United States)]|[Argonne National Lab., IL (United States)

1995-04-01

395

Proximity fingerprint of s{plus_minus} superconductivity.  

SciTech Connect

We suggest a straightforward and unambiguous test to identify possible opposite signs of the superconducting order parameter in different bands proposed for iron-based superconductors (s{sub {+-}}-state). We consider the proximity effect in a weakly coupled sandwich composed of a s{sub {+-}}-superconductor and a thin layer of the s-wave superconductor. In such system the s-wave order parameter is coupled differently with different s{sub {+-}}-gaps and it typically aligns with one of these gaps. This forces the other s{sub {+-}}-gap to be anti-aligned with the s-wave gap. In such situation the aligned band induces a peak in the s-wave density of states (DoS), while the anti-aligned band induces a dip. Observation of such contact-induced negative feature in the s-wave DoS would provide a definite proof for s{sub {+-}}-superconductivity.

Koshelev, A. E.; Stanev, V. (Materials Science Division)

2011-01-01

396

Residential proximity to high voltage transmission lines and depressive symptomatology  

SciTech Connect

A number of epidemiological studies indicate an association between depression and proximity to high voltage transmission lines. These studies have been criticized, however, for using surrogate measures of electromagnetic fields (EMFs) and unstandardized measures of depression. In an effort to overcome these limitations, the Center for Epidemiological Studies Depression (CES-D) scale was administered to 152 women living either adjacent to a transmission line or one block away. Results indicate that homes adjacent to the transmission lines have an average EMF level of 4.86 milligauss at their front door and those one block away have an average of 0.68 milligauss. There was no significant difference in CES-D scores between the groups, controlling for demographic variables. There appeared to be an increase in other health effects, including cancer and miscarriages, but these findings were preliminary and need further investigation.

McMahan, S.G.

1992-01-01

397

Proximal and point detection of contaminated surfaces using Raman spectroscopy  

NASA Astrophysics Data System (ADS)

We are actively investigating the use of Raman spectroscopy for proximal standoff detection of chemicals and explosive materials on surfaces. These studies include Raman Chemical Imaging of contaminated fingerprints for forensic attribution and the assessments of commercial handheld or portable Raman instruments operating with near-infrared (IR) as well as ultraviolet (UV) laser excitation specifically developed for on-the-move reconnaissance of chemical contamination. As part of these efforts, we have measured the Raman cross sections of chemical agents, toxic industrial chemicals, and explosives from the UV to NIR. We have also measured and modeled the effect interrogation angle has on the Raman return from droplets on man-made surfaces. Realistic droplet distributions have been modeled and tested against variations in surface scan patterns and laser spot size for determining the optimum scan characteristics for detection of relevant surface contamination.

Guicheteau, Jason A.; Christesen, Steven D.; Tripathi, Ashish; Emmons, Erik D.; Wilcox, Phillip G.; Emge, Darren K.; Pardoe, Ian J.; Fountain, Augustus W., III

2011-10-01

398

Proximal Tubule Cell Hypothesis for Cardiorenal Syndrome in Diabetes  

PubMed Central

Incidence of cardiovascular disease (CVD) is remarkably high among patients with chronic kidney disease (CKD), even in the early microalbuminuric stages with normal glomerular filtration rates. Proximal tubule cells (PTCs) mediate metabolism and urinary excretion of vasculotoxic substances via apical and basolateral receptors and transporters. These cells also retrieve vasculoprotective substances from circulation or synthesize them for release into the circulation. PTCs are also involved in the uptake of sodium and phosphate, which are critical for hemodynamic regulation and maintaining the mineral balance, respectively. Dysregulation of PTC functions in CKD is likely to be associated with the development of CVD and is linked to the progression to end-stage renal disease. In particular, PTC dysfunction occurs early in diabetic nephropathy, a leading cause of CKD. It is therefore important to elucidate the mechanisms of PTC dysfunction to develop therapeutic strategies for treating cardiorenal syndrome in diabetes.

Saito, Akihiko; Kaseda, Ryohei; Hosojima, Michihiro; Sato, Hiroyoshi

2011-01-01

399

Magnetic screening in proximity effect Josephson-junction arrays  

NASA Astrophysics Data System (ADS)

The modulation with magnetic field of the sheet inductance measured on proximity effect Josephson-junction arrays (JJAs) is progressively vanishing on lowering the temperature, leading to a low-temperature field-independent response. This behaviour is consistent with the decrease of the two-dimensional penetration length below the lattice parameter. Low-temperature data are quantitatively compared with theoretical predictions based on the XY model in the absence of thermal fluctuations. The results show that the description of a JJA within the XY model is incomplete and the system is put well beyond the weak screening limit which is usually assumed in order to invoke the well-known frustrated XY model describing classical Josephson-junction arrays.

Tesei, M.; Théron, R.

2009-03-01

400

Model calculations of the proximity effect in finite multilayers  

NASA Astrophysics Data System (ADS)

The proximity-effect theory developed by Takahashi and Tachiki for infinite superconductor/normal (S/N) multilayers is applied to multilayer systems with a finite number of layers in the growth direction. The purpose is to investigate why previous applications to infinite multilayers fail to describe the measured data satisfactorily. It is shown that surface superconductivity may appear, depending on the thickness of the covering normal metallic layers, on both the top and the bottom. Most of the parameters used refer to the V/Ag system, but systems in which the N metal is also a superconductor are considered as well. The nucleation process is studied as a function of the system parameters, including the transparency of the S/N interface.

Ciuhu, C.; Lodder, A.

2001-08-01

401

Endovascular treatment of proximal arsastomotic aneurysms after aortic prosthetic reconstruction  

SciTech Connect

Purpose: To describe the efficacy and value of endovascular stent-grafts for the treatment of aortic anastomotic pseudo-aneurysms.Methods: Three patients with proximal aortic anastomotic pseudoaneurysms 8-15 years after prosthetic reconstruction were treated by transfemoral stent-graft implantation. In two patients the pseudoaneurysms were excluded by Talent prostheses [tube graft (n=1), bifurcated graft (n=s1)]. In one patient an uniiliac Zenith stent-graft was implanted and an extra-anatomic crossover bypass for revascularization of the contralateral lower extremity was performed.Results: All procedures were successful with primary exclusion of the pseudoaneurysms. During the follow-up (mean 16 months) one endoleak occurred due to migration of the tube stent-graft. The endoleak was sealed successfully by implanting an additional bifurcated stent-graft.Conclusion: Stent-graft exclusion of aortic pseudoaneurysms offers a minimally invasive and safe alternative to open surgical reconstruction.

Tiesenhausen, Kurt [University Hospital Graz, Department of Vascular Surgery (Austria); Hausegger, Klaus A.; Tauss, Josef [University Hospital Graz, Department of Radiology (Austria); Amann, Wilfried; Koch, Guenter [University Hospital Graz, Department of Vascular Surgery (Austria)

2001-01-15

402

Endovascular Treatment of Proximal Anastomotic Aneurysms After Aortic Prosthetic Reconstruction  

SciTech Connect

Purpose: To describe the efficacy and value of endovascular stent-grafts for the treatment of aortic anastomotic pseudoaneurysms.Methods: Three patients with proximal aortic anastomotic pseudoaneurysms 8-15 years after prosthetic reconstruction were treated by transfemoral stent-graft implantation. In two patients the pseudoaneurysms were excluded by Talent prostheses [tube graft (n = 1), bifurcated graft (n = 1)]. In one patient an uni iliac Zenith stent-graft was implanted and an extra-anatomic crossover bypass for revascularization of the contralateral lower extremity was performed.Results: All procedures were successful with primary exclusion of the pseudoaneurysms. During the follow-up (mean 16 months) one endoleak occurred due to migration of the tube stent-graft. The endoleak was sealed successfully by implanting an additional bifurcated stent-graft.Conclusion: Stent-graft exclusion of aortic pseudoaneurysms offers a minimally invasive and safe alternative to open surgical reconstruction.

Tiesenhausen, Kurt [Department of Vascular Surgery, University Hospital Graz, Auenbruggerplatz 29, A-8036 Graz (Austria); Hausegger, Klaus A.; Tauss, Josef [Department of Radiology, University Hospital Graz, Auenbruggerplatz 29, A-8036 Graz (Austria); Amann, Wilfried; Koch, Guenter [Department of Vascular Surgery, University Hospital Graz, Auenbruggerplatz 29, A-8036 Graz (Austria)

2001-01-15

403

Troubled proximities: asylums cemeteries in nineteenth-century England.  

PubMed

Asylums and cemeteries in nineteenth-century England were kindred spirits in the anxiety and exclusionary impulses that they engendered, leading them to be similarly exiled from nineteenth-century urban areas. They were uneasy 'neighbours', however, with contemporary authorities condemning the proximity of cemeteries to asylums on medical and moral grounds. The appearance at many asylums after mid-century of a burial-ground for deceased residents, usually located on an asylum's own estate, was often criticized on grounds similar to those raised with respect to neighbouring parochial burial-grounds. Other objections arose to the 'exclusivity' of asylum-based burials, with off-site burial arrangements clearly being favoured. One consequence was that on-site asylum cemeteries ended up being treated as unwelcome occupants of asylum estates, hidden away as an embarrassment, creating a legacy of anonymity still generating concerns in the present. PMID:22701930

Philo, Chris

2012-03-01

404

Residential proximity to environmental hazards and adverse health outcomes.  

PubMed

How living near environmental hazards contributes to poorer health and disproportionate health outcomes is an ongoing concern. We conducted a substantive review and critique of the literature regarding residential proximity to environmental hazards and adverse pregnancy outcomes, childhood cancer, cardiovascular and respiratory illnesses, end-stage renal disease, and diabetes. Several studies have found that living near hazardous wastes sites, industrial sites, cropland with pesticide applications, highly trafficked roads, nuclear power plants, and gas stations or repair shops is related to an increased risk of adverse health outcomes. Government agencies should consider these findings in establishing rules and permitting and enforcement procedures to reduce pollution from environmentally burdensome facilities and land uses. PMID:22028451

Brender, Jean D; Maantay, Juliana A; Chakraborty, Jayajit

2011-10-25

405

Automobile proximity and indoor residential concentrations of BTEX and MTBE  

SciTech Connect

Attached garages have been identified as important sources of indoor residential air pollution. However, the literature lacks information on how the proximity of cars to the living area affects indoor concentrations of gasoline-related compounds, and the origin of these pollutants. We analyzed data from the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study and evaluated 114 residences with cars in an attached garage, detached garage or carport, or without cars. Results indicate that homes with cars in attached garages were affected the most. Concentrations in homes with cars in detached garages and residences without cars were similar. The contribution from gasoline-related sources to indoor benzene and MTBE concentrations appeared to be dominated by car exhaust, or a combination of tailpipe and gasoline vapor emissions. Residing in a home with an attached garage could lead to benzene exposures ten times higher than exposures from commuting in heavy traffic.

Corsi, Dr. Richard [University of Texas, Austin; Morandi, Dr. Maria [University of Texas Health Science Center, Houston; Siegel, Dr. Jeffrey [University of Texas, Austin; Hun, Diana E [ORNL

2011-01-01

406

The electrogenic Na/HCO3 cotransporter.  

PubMed

The electrogenic Na/HCO3 cotransporter (symporter) is the major HCO3- transporter of the renal proximal tubule (PiT), located at the basolateral membrane (BLM), and also plays a noteworthy role in Na+ reabsorption. HCO3 transporters are important for regulation of intracellular pH (pHi) in most cells and also thereby regulate blood pH. This electrogenic Na/HCO3 cotransporter was first discovered using perfused Ambystoma tigrinum (salamander) renal, proximal tubules. This novel cotransporter mediates the movement of one Na+ ion with several HCO3- ions, making it electrogenic, is blocked by stilbene compounds, but does not depend on intra- or extracellular Cl-. This and similar cotransporters have been found in a number of tissues and cell types. Recently, we used Xenopus-laevis oocytes to expression clone the salamander renal electrogenic Na Bicarbonate Cotransporter (NBC). Using microelectrodes to monitor membrane potential (Vm) and intracellular pH (pHi), we followed oocyte expression after injecting poly (A)+, fractioned poly (A)+, or cRNA. All experimental solutions contained 100 microM ouabain to block the Na+/K+ pump. Our expression assay was to apply 1.5% CO2/10 mM HCO3- (pH 7.5), allow pHi to stabilize from the CO2-induced acidification, and then remove bath Na+. Removing bath Na+ from native oocytes and water-injected controls, hyperpolarized the oocytes by approximately 5 mV and had no effect on pHi. However, for oocytes injected with poly (A)+ RNA, removing Na+ transiently depolarized the cell by approximately 10 mV and caused pHi to decrease; both effects were blocked by 4,4'-diisothiocyano-2,2'-stilbenedisulfonate (DIDS) and required HCO3-. Electrophoretic fractionation of the poly (A)+ RNA, enriched the expression signal. From the optimal expression-fraction, we constructed a size-selected cDNA library in pSPORT1. Screening our Ambystoma library yielded a single clone (aNBC). We could detect expression 3 days after injection of NBC cRNA. In aNBC-expressing oocytes, adding CO2/HCO3-elicited a large (> 50mV) and rapid hyperpolarization, followed by a partial relaxation as pHi stabilized. Na+ removal in CO2/HCO3-depolarized the cell by > 40mV and decreased pHi, aNBC encodes a protein of 1035 amino acids with several putative membrane-spanning domains, and has a low level of amino-acid homology (approximately 30% to the AE family of Cl-HCO3 exchangers. aNBC is the first member of a new family of Na(+)-linked HCO3- transporters and, together with the AE family, defines a new superfamily of HCO3- transporters. Using aNBC to screen a rat-kidney cDNA library, we identified a full-length cDNA clone (rNBC), rNBC encodes a protein of 1035 amino acids, is 86% identical to aNBC, and can be functionally expressed in oocytes. PMID:9261985

Boron, W F; Fong, P; Hediger, M A; Boulpaep, E L; Romero, M F

1997-06-27

407

Closure of proximal colorectal fistulas using fibrin sealant.  

PubMed

Fibrin glue has been used in upper gastrointestinal and perianal fistula disease, but its success in proximal colorectal pathology has not been widely documented. This report describes the use of endoscopically injected fibrin glue as a successful adjunct to traditional methods in accelerating the closure of colorectal fistulas. A retrospective review was performed on cases of colon and rectal fistulas treated with fibrin glue using an endoscopic technique of injection. Fistulas were injected via a flexible fiberoptic endoscope with fluoroscopic guidance (three) or directly with a rigid proctoscope (one). Fibrin glue was mixed directly from cryoprecipitate, thrombin, and calcium (one) or using a Tisseel kit (three) (Baxter, Deerfield, IL). Four patients were identified and included: two J-pouch fistulas, a colocutaneous fistula, and a complex rectocutaneous fistula. The median duration of fistula was 33 days (range 4-365 days). Total parenteral nutrition and bowel rest were used in two patients and three required drainage of an abscess. All fistulas were obliterated and patients required a mean of one application of fibrin glue (range one to two). The mean time to resuming a regular diet postinjection was 2 days (range 1-5). No complications were identified. Fistula resolution was documented in all cases with a contrast enema and no patient has had a fistula recurrence at a median follow-up of 12 months (range 6-65). This preliminary series demonstrates that fibrin glue can be used to obliterate proximal rectal, colonic, and pouch fistulas. Endoscopy and fluoroscopy may aid in administering the fibrin glue. This adjunctive technique may shorten the time to fistula closure and may allow some patients to avoid further surgery. PMID:12132744

Lamont, Jeffrey P; Hooker, Glen; Espenschied, Jonathan R; Lichliter, Warren E; Franko, Edward

2002-07-01

408

Speciated Human High Density Lipoprotein Protein Proximity Profiles†  

PubMed Central

It is expected that the attendant structural heterogeneity of human high density lipoprotein (HDL) complexes is a determinant of its varied metabolic functions. To determine structural heterogeneity of HDL, major apolipoprotein stoichiometry profiles in human HDL were determined. First, HDL was separated into two main populations, with and without apolipoprotein (apo) A-II, LpA-I and LpA-I/A-II respectively. Each main population was further separated into six individual subfractions using size exclusion chromatography (SEC). Protein proximity profiles (PPP) of major apolipoproteins in each individual subfraction was determined by optimally cross-linking apolipoproteins within individual particles with bis(sulfosuccinimidyl)suberate (BS3), a bifunctional cross linker, followed by molecular weight determination by MALDI-MS. The PPPs of LpA-I subfractions indicated that the number of apoA-I molecules increased from two to three to four upon increase in the LpA-I particle size. On the other hand, the entire population of LpA-I/A-II demonstrated the presence of only two proximal apoA-I molecules per particle, while the number of apoA-II molecules varied from one dimeric apoA-II to two and then to three. For most of the above PPP profiles, an additional population that contained a single molecule of apoC-III in addition to apoA-I and/or apoA-II was detected. Upon composition analyses of individual subpopulations, LpA-I/A-II displayed comparable proportions for total protein (~58%), phospholipids (~21%) total cholesterol (~16%), triglycerides (~5%) and free cholesterol (~4%) across subfractions. LpA-I components, on the other hand, showed significant variability. This novel information on HDL subfractions will form a basis for better understanding particle specific functions of HDL.

Gauthamadasa, Kekulawalage; Rosales, Corina; Pownall, Henry J.; Macha, Stephen; Jerome, W. Gray; Huang, Rong; Silva, R. A.Gangani. D.

2010-01-01

409

Electrophysiological evidence for Cl secretion in shark renal proximal tubules.  

PubMed

The electrophysiology of shark proximal tubules (Squalus acanthias) was investigated using conventional microelectrodes and cable analysis. Under in vitro perfusion with symmetrical Ringer solutions, tubule transepithelial resistance was 36.3 +/- 2.3 omega X cm2 (means +/- SE, n = 44). Other electrophysiological variables varied widely under control conditions. In unstimulated tubules (n = 16) the transepithelial voltage (VT,o) was lumen positive (1.2 +/- 0.2 mV), the basolateral membrane potential (Vbl,x) was -61.3 +/- 1.6 mV, and the fractional resistance of the apical membrane (fRa) was 0.67 +/- 0.02. Spontaneously stimulated tubules (n = 28) had lumen-negative VT,o values (-1.5 +/- 0.4 mV), low Vbl,x values (-41.3 +/- 1.7 mV), and low fRa values (0.30 +/- 0.02). The stimulated state can be induced in unstimulated tubules via treatment with cAMP. Multiple microelectrode impalements in a single tubule revealed epithelial cells sharing similar electrophysiological properties. Selective ion substitutions in the tubule lumen and peritubular bath uncovered an increased Cl conductance in the apical membrane of spontaneously and cAMP-stimulated tubules. Anthracene-9-carboxylic acid tended to reverse the stimulated state, and furosemide hyperpolarized Vbl,x. These results constitute the first evidence for secretory Cl transport in a renal proximal tubule. The electrophysiological responses to ion substitutions, stimulators, and inhibitors are strikingly similar to those of known Cl-transporting epithelia. PMID:3970217

Beyenbach, K W; Frömter, E

1985-02-01

410

Presynaptic modulation of cholinergic neurotransmission in the human proximal stomach  

PubMed Central

This study investigates whether the cholinergic neurones, innervating the human proximal stomach, can be modulated by nitric oxide (NO) or vasoactive intestinal polypeptide (VIP), or via presynaptic muscarinic, ?2- or 5-hydroxytryptamine4 (5-HT4-) receptors.Circular muscle strips, without mucosa, were incubated with [3H]-choline to incorporate [3H]-acetylcholine into the cholinergic transmitter stores. The basal and electrically-induced release of tritium and [3H]-acetylcholine were analysed in a medium containing guanethidine (4×10?6?M), hemicholinium-3 (10?5?M), physostigmine (10?5?M) and atropine (10?6?M). Tissues were stimulated twice for 2?min (S1 and S2: 40?V, 1?ms, 4?Hz) and drugs were added before S2.The NO synthase inhibitor L-NG-nitroarginine methyl ester (3×10?4?M) and the NO donor sodium nitroprusside (10?5?M), as well as VIP (10?7?M) did not influence the basal release nor the electrically-evoked release.The ?2-adrenoceptor agonist UK-14,304 (10?5?M) significantly inhibited the electrically-evoked release of [3H]-acetylcholine, and this was prevented by the ?2-adrenoceptor antagonist rauwolscine (2×10?6?M).The 5-HT4-receptor agonist prucalopride (3×10?7?M) significantly enhanced the electrically-evoked release of [3H]-acetylcholine, and the 5-HT4-receptor antagonist SB204070 (10?9?M) prevented this.When atropine (10?6?M) was omitted from the medium and added before the second stimulation, it significantly increased the release of [3H]-acetylcholine.These results suggest that the release of acetylcholine from the cholinergic neurones, innervating the circular muscle in the human proximal stomach, can be inhibited via presynaptic muscarinic auto-receptors and ?2-adrenoceptors, and stimulated via presynaptic 5-HT4-receptors. No evidence for modulation by NO or VIP was obtained.

Leclere, Pascal G; Lefebvre, Romain A

2002-01-01

411

Proximity effect in normal metal/ferromagnet/d-wave superconductor structures  

NASA Astrophysics Data System (ADS)

The superconducting proximity effect in normal metal/insulator/ferromagnet/d-wave superconductor (N/I/F/D) structures is studied based on an extended Blonder Tinkham Klapwijk (BTK) theory. The transition from the “0” to “?” state is found in the conductance spectra with increasing thickness of F or the ferromagnetic exchange energy. The superconducting proximity effect is drastically changed by the orientation angle ?, as ? increases the proximity effect is enhanced, being strongest for ?/? = 0.25.

Li, Hong; Yang, Wei; Yang, Xinjian; Qin, Minghui; Xu, Yihong

2007-01-01

412

Insufficiency fracture of the proximal fibula and then tibia: a case report.  

PubMed

Elderly people with osteoarthritis of the knee and postpartum women are at risk of insufficiency fractures of the proximal fibular or tibia. We report on an 82-year-old woman with valgus osteoarthritis of the knee who developed insufficiency fractures of the right proximal fibula and then the right proximal tibia. She underwent total knee arthroplasty using a long tibial stem and a tibial locking plate with the Less Invasive Stabilization System. PMID:23630000

Cheung, Man Hong Steve; Lee, Man-fai; Lui, Tun Hing

2013-04-01

413

Studies on the Mechanism of 4-Aminophenol-induced Toxicity to Renal Proximal Tubules  

Microsoft Academic Search

4-Aminophenol (PAP) is known to cause nephrotoxicity in the rat where it produces selective necrosis to renal proximal tubules. The aim of this work was to investigate the toxicity of PAP and its known nephrotoxic metabolite 4-amino-3-S-glutathionylphenol using a well defined suspension of rabbit renal proximal tubules. PAP at a concentration of 0.5 mM and 1 mM caused proximal tubule

Edward A. Lock; Theresa J. Cross; Rick G. Schnellmann

1993-01-01

414

Bone mineral density in patients with cervical and trochanteric fractures of the proximal femur  

Microsoft Academic Search

The bone mineral density (BMD) of the proximal femur, spine and radius shaft was determined in 75 women with atraumatic fractures of the proximal femur (FXf) (average age: 70.1±9.6 years) and 51 controls of similar age. Fractures were classified as either cervical (n=36) or trochanteric (n=39) on the basis of radiographic and surgical finding. The BMD of spine and proximal

E. Vega; C. Mautalen; H. Gómez; A. Garrido; L. Melo; A. O. Sahores

1991-01-01

415

International transfer of knowledge: The role of international trade and geographic proximity  

Microsoft Academic Search

International Transfer of Knowledge: The Role of International Trade and Geographic Proximity. —The paper examines empirically\\u000a the effect of international trade and geographic proximity on knowledge inflow to Sweden. Swedish patent data is used to trace\\u000a knowledge flows. Both geographic proximity and international trade are in a first estimation found to affect knowledge flows.\\u000a An extreme bounds analysis is conducted

Fredrik Sjöholm

1996-01-01

416

Proximal tibiofibular synostosis as a possible cause of a pseudoradicular syndrome: a case report  

Microsoft Academic Search

This paper presents a case report of persistent low back pain and suspected lumbar radiculopathy. A synostosis at the level\\u000a of the proximal tibiofibular joint was diagnosed. After successful resection of the synostosis, the low back symptoms resolved\\u000a completely. This is the first report of a proximal tibiofibular synostosis as a possible cause of referred pain proximally.

Bas van OoijAndrevan OoijJ; André van Ooij; J. Wim Morrenhof; C. Niek van Dijk

417

Investigation of sodium distribution in phosphate glasses using spin-echo {sup 23}Na NMR  

SciTech Connect

The spatial arrangements of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O{sm{underscore}bullet}(100{minus}x)P{sub 2}O{sub 5} (x {le} 55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling, and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases nonlinearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model, and a pairwise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS models, it is demonstrated that the slight nonlinear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and nonclustered distributions becomes more difficult at higher sodium concentrations.

Alam, T.M.; McLaughlin, J.; Click, C.C.; Conzone, S.; Brow, R.K.; Boyle, T.J.; Zwanziger, J.W.

2000-02-24

418

Investigation of Sodium Distribution in Phosphate Glasses Using Spin-Echo {sup 23}Na NMR  

SciTech Connect

The spatial arrangement of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O(100-x)P{sub 2}O{sub 5} (x<55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases non-linearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model and a pair-wise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS model, it is demonstrated that the slight non-linear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and non-clustered distributions becomes more difficult at higher sodium concentrations.

ALAM, TODD M.; BOYLE, TIMOTHY J.; BROW, RICHARD K.; CLICK, CAROL C.; CONZONE, SAM; McLAUGHLIN, JAY; ZWANZIGER, JOE

1999-09-16

419

The effect of proximally and fully porous-coated canine hip stem design on bone modeling.  

PubMed

Porous coated canine femoral hip replacement implants were evaluated for biological fixation by bone ingrowth and the effect of the extent of porous coating on bone modeling. The Co-Cr alloy implants were either fully porous coated or coated only on the proximal 40% of the stem. Two implants of each type were studied 9, 16, and 36 months after surgery. Implant fixation and bone modeling were assessed radiographically throughout the implant periods and histologically after the test animals were killed. All 12 implants appeared stably fixed within the femur and were bone-ingrown in the porous region. Radiographic features such as proximal medial and anterior cortical thinning, proximal cancellous bone hypertrophy, and new endosteal bone formation near the stem tip were noted within the first postoperative year, with no appreciable change thereafter. The extent of proximal cortical thinning varied from virtually none to as much as 40%, being more prominent with the proximally coated implants at 16 months and with the fully coated implants at 36 months. Of consistent note was cancellous hypertrophy at the junction of porous and smooth implant surfaces with proximally coated implants and new endosteal bone formation and ingrowth at the stem tip of fully coated implants. These results indicate that the proximally porous-coated implant design causes increased proximal stress transfer, but this does not necessarily preclude proximal cortical resorption. PMID:3305844

Bobyn, J D; Pilliar, R M; Binnington, A G; Szivek, J A

1987-01-01

420

Physically-proximal human-robot collaboration for air and space applications  

Microsoft Academic Search

In Aerospace applications, human safety is of paramount importance given harsh environmental conditions that require persistent electromechanical life support. The resulting inherent proximity between humans and \\

Ella M. Atkins

2007-01-01

421

Proteomic profiling of the effect of metabolic acidosis on the apical membrane of the proximal convoluted tubule.  

PubMed

The physiological response to the onset of metabolic acidosis requires pronounced changes in renal gene expression. Adaptations within the proximal convoluted tubule support the increased extraction of plasma glutamine and the increased synthesis and transport of glucose and of NH(4)(+) and HCO(3)(-) ions. Many of these adaptations involve proteins associated with the apical membrane. To quantify the temporal changes in these proteins, proteomic profiling was performed using brush-border membrane vesicles isolated from proximal convoluted tubules (BBMV(PCT)) that were purified from normal and acidotic rats. This preparation is essentially free of contaminating apical membranes from other renal cortical cells. The analysis identified 298 proteins, 26% of which contained one or more transmembrane domains. Spectral counts were used to assess changes in protein abundance. The onset of acidosis produced a twofold, but transient, increase in the Na(+)-dependent glucose transporter and a more gradual, but sustained, increase (3-fold) in the Na(+)-dependent lactate transporter. These changes were associated with the loss of glycolytic and gluconeogenic enzymes that are contained in the BBMV(PCT) isolated from normal rats. In addition, the levels of ?-glutamyltranspeptidase increased twofold, while transporters that participate in the uptake of neutral amino acids, including glutamine, were decreased. These changes could facilitate the deamidation of glutamine within the tubular lumen. Finally, pronounced increases were also observed in the levels of DAB2 (3-fold) and myosin 9 (7-fold), proteins that may participate in endocytosis of apical membrane proteins. Western blot analysis and accurate mass and time analyses were used to validate the spectral counting. PMID:22357915

Walmsley, Scott J; Freund, Dana M; Curthoys, Norman P

2012-02-22

422

Proximal femur structural geometry changes during and following lactation  

PubMed Central

Human lactation is associated with transient decreases in bone mineral density (BMD). Bone strength is related to both mass and structural geometry. This study investigated longitudinal changes of hip bone strength during lactation using hip structural analysis (HSA), which determines hip structural geometry (including areal BMD, BMDa) from dual-energy X-ray absorptiometry scans (DXA). Forty-eight lactating women were studied longitudinally at the proximal femur using DXA at approximately 2 weeks postpartum, peak-lactation and post-lactation. Nonpregnant, nonlactating women (NPNL, n = 23) were studied concurrently at baseline and after 1 year. Hip scans were analysed using HSA at the narrow neck, intertrochanter and proximal shaft. No significant change (> 0.05) was observed in NPNL women for any measurement. In contrast, for lactating women BMDa decreased significantly from 2 weeks postpartum to peak-lactation at narrow neck (?2.8%), intertrochanter (?3.2%) and shaft (?1.4%). Cross-sectional area (CSA) decreased at narrow neck (?3.4%) and intertrochanter (?2.7%). There were no significant changes in bone width. Section modulus decreased at intertrochanter (?2.1%). At shaft, cortical thickness decreased (?1.7%) and buckling ratio increased (2.3%). By post-lactation, measurements were not significantly different from 2 weeks postpartum except for decrements in BMDa (?1.1%) and CSA (? 1.2%) at the shaft. During the study, lactating women lost 5% of their body weight. Adjusting for weight changes decreased the magnitude and significance of HSA changes at peak-lactation and by post-lactation there were no significant differences from 2 weeks postpartum. Calcium intake was not a significant predictor of changes in HSA variables. In conclusion, lactation is associated with significant but transient changes in hip BMD and structural geometry. Changes in body weight but not calcium intake were associated with these changes. These small changes at the hip during lactation occurred mainly at internal surfaces and had minimal impact on bending or compressive strength.

Laskey, M.A.; Price, R.I.; Khoo, B.C.C.; Prentice, A.

2011-01-01

423

Fractures of the Proximal Fifth Metatarsal: Percutaneous Bicortical Fixation  

PubMed Central

Background Displaced intraarticular zone I and displaced zone II fractures of the proximal fifth metatarsal bone are frequently complicated by delayed nonunion due to a vascular watershed. Many complications have been reported with the commonly used intramedullary screw fixation for these fractures. The optimal surgical procedure for these fractures has not been determined. All these observations led us to evaluate the effectiveness of percutaneous bicortical screw fixation for treating these fractures. Methods Twenty-three fractures were operatively treated by bicortical screw fixation. All the fractures were evaluated both clinically and radiologically for the healing. All the patients were followed at 2 or 3 week intervals till fracture union. The patients were followed for an average of 22.5 months. Results Twenty-three fractures healed uneventfully following bicortical fixation, with a mean healing time of 6.3 weeks (range, 4 to 10 weeks). The average American Orthopaedic Foot & Ankle Society (AOFAS) score was 94 (range, 90 to 99). All the patients reported no pain at rest or during athletic activity. We removed the implant in all cases at a mean of 23.2 weeks (range, 18 to 32 weeks). There was no refracture in any of our cases. Conclusions The current study shows the effectiveness of bicortical screw fixation for displaced intraarticular zone I fractures and displaced zone II fractures. We recommend it as one of the useful techniques for fixation of displaced zone I and II fractures.

Mahajan, Vivek; Chung, Hyun Wook

2011-01-01

424

The proximity of hotspots to convergent and divergent plate boundaries  

SciTech Connect

An analysis of four different hotspot distributions, ranging from Morgan's (1972) original list of 19 to Vogt's (1981) list of 117 reveals that the hotspots are preferentially located near divergent plate boundaries. The probability of this proximity occurring by chance alone is quite remote, less than 0.01 for all four hotspots distributions. The same analysis also reveals that the hotspots are preferentially excluded from regions near convergent plate boundaries. The probability of this exclusion occurring by chance alone is 0.1 or less for three out of the four distributions examined. The authors interpret this behavior as being a consequence of the effects of large scale convective circulation on ascending mantle plumes. Mantle thermal plumes, the most probable source of hotspots, arise from instabilities in a basal thermal boundary layer. Plumes are suppressed from regions beneath convergent boundaries by descending flow and are entrained into the upwelling flow beneath spreading centers. Plate-scale convective driven by subduction may also advect mantle thermal plumes toward spreading centers.

Weinstein, S.A.; Olson, P.L. (Johns Hopkins Univ., Baltimore, MD (USA))

1989-05-01

425

Electrical capacitance tomography using an accelerated proximal gradient algorithm.  

PubMed

Image reconstruction in electrical capacitance tomography requires a solution of an ill-posed inverse problem. This paper applies an accelerated proximal gradient (APG) singular value thresholding algorithm, which is originally proposed for the matrix completion problem, to image two-phase flow. Aiming to improve the image quality, a nuclear norm-based regularization technique is adopted to treat the ill-posedness of the inverse problem, and a simple updating technique is used to update the sensitivity matrix. Both typical and complicated distributions (e.g., "sun-rise" and cross-shape), have been examined based on a 16-electrode configuration. The results showed that the APG algorithm with updated sensitivity matrix could produce higher quality images when compared to the algorithm based on the typical sensitivity matrix. Both simulation and experiment results indicate that the algorithm developed has been able to achieve good quality reconstructed images with relativity fast computation speed for the cases tested in this paper. PMID:22559536

Xue, Qian; Wang, Huaxiang; Cui, Ziqiang; Yang, Chengyi

2012-04-01

426

Active membrane masks for improved overlay performance in proximity lithography  

NASA Astrophysics Data System (ADS)

Membrane masks are thin (2 micron x 35 mm x 35 mm) structures that carry the master exposure patterns in proximity (X-ray) lithography. With the continuous drive to the printing of ever-finer features in microelectronics, the reduction of mask-wafer overlay positioning errors by passive rigid body positioning and passive stress control in the mask becomes impractical due to nano and sub-micron scale elastic deformations in the membrane mask. This paper describes the design, mechanics and performance of a system for actively stretching a membrane mask in-plane to control overlay distortion. The method uses thermoelectric heating/cooling elements placed on the mask perimeter. The thermoelectric elements cause controlled thermoelastic deformations in the supporting wafer, which in turn corrects distortions in the membrane mask. Silicon carbide masks are the focus of this study, but the method is believed to be applicable to other mask materials, such as diamond. Experimental and numerical results will be presented, as well as a discussion of the design issues and related design decisions.

Huston, Dryver R.; Plumpton, James; Esser, Brian; Sullivan, Gerald A.

2004-07-01

427

Proximity Queries between Interval-Based CSG Octrees  

SciTech Connect

This short paper is concerned with a new algorithm for collision and distance calculation between CSG octrees, a generalization of an octree model created from a Constructive Solid Geometry (CSG) object. The data structure uses interval arithmetic and allows us to extend the tests for classifying points in space as inside, on the boundary, or outside a CSG object to entire sections of the space at once. Tree nodes with additional information about relevant parts of the CSG object are introduced in order to reduce the depth of the required subdivision. The new data structure reduces the input complexity and enables us to reconstruct the CSG object. We present an efficient algorithm for computing the distance between CSG objects encoded by the new data structure. The distance algorithm is based on a distance algorithm for classical octrees but, additionally, it utilizes an elaborated sort sequence and differentiated handling of pairs of octree nodes to enhance its efficiency. Experimental results indicate that, in comparison to common octrees, the new representation has advantages in the field of proximity query.

Dyllong, Eva; Grimm, Cornelius [University of Duisburg-Essen, Institute of Computer Science, Lotharstrasse 65, 47048 Duisburg (Germany)

2007-09-06

428

Dynamics and control of satellite relative motion in proximity operations  

NASA Astrophysics Data System (ADS)

In this dissertation, the development of relative navigation, guidance, and control algorithms of an autonomous space rendezvous and docking system are presented. These algorithms are based on innovative formulations of the relative motion equations that are completely explicit in time. The navigation system uses an extended Kalman filter based on these formulations to estimate the relative position and velocity of the chaser vehicle with respect to the target vehicle and the chaser attitude and gyro biases. This filter uses the range and angle measurements of the target relative to the chaser from a simulated LIDAR system, along with the star tracker and gyro measurements of the chaser. The corresponding measurement models, process noise matrix, and other filter parameters are provided. The guidance and control algorithms are based on the glideslope used in the past for rendezvous and proximity operations of the Space Shuttle with other vehicles. These algorithms are used to approach, flyaround, and to depart from a target vehicle in elliptic orbits. The algorithms are general and able to translate the chaser vehicle in any direction, decelerate while approaching the target vehicle, and accelerate when moving away. Numerical nonlinear simulations that illustrate the relative navigation, attitude estimation, guidance, and control algorithm's, as well as performance and accuracy are evaluated in the research study.

Okasha, Mohamed Elsayed Aly Abd Elaziz

429

The proximity effect around high-redshift galaxies  

NASA Astrophysics Data System (ADS)

Recent observations have shown that the intergalactic medium (IGM) is more transparent to Ly? photons close to Lyman break galaxies (LBGs) than at large distance from them, i.e. there is a proximity effect. Cosmological simulations including winds from LBGs have been so far unable to explain this trend. By coupling such simulations with the radiative transfer code CRASH, we investigate whether the addition of the ionizing radiation emitted by LBGs can increase the transmissivity by decreasing the neutral hydrogen fraction in the inner Mpc of the galaxy halo. The transmissivity as a function of distance is roughly reproduced only if LBGs are identified with dwarf galaxies (with masses <~ 109 Msolar) which are undergoing a vigorous (50 Msolar yr-1) burst of star formation. Similar star formation rates in larger galaxies are not sufficient to overwhelm the large recombination rates associated with their denser environment. If so, photoionization partly reconciles theory with observations, although we discuss a number of uncertainties affecting both approaches.

Maselli, A.; Ferrara, A.; Bruscoli, M.; Marri, S.; Schneider, R.

2004-05-01

430

Norepinephrines effect on adenosine transport in the proximal straight tubule  

SciTech Connect

The effect of norepinephrine on C/sup 14/-adenosine transport in the rabbit proximal tubule (S/sub 2/) was studied. The transepithelial transport of adenosine (0.02 mM0 from lumin to bathing solution was measured by its rate of appearance (J/sub A/) in the bathing solution and by its disappearances (J/sub D/) from the luminal fluid. Norepinephrine (0.24 ..mu..M) was added to the bathing solution after a control flux period. After three samples from the experiment period the tubules were quickly harvested and the cellular concentration of C/sup 14/-adenosine was determined. The high cellular adenosine concentration and th marked difference in adenosine appearance rate in the bathing solution compared to the luminal disappearance rate indicates the absorbed adenosine is trapped in the cells. This trapping may be due to adenosine metabolism or difficulty of crossing the basolateral membrane. Whichever is the case, norepinephrine appears to stimulate movement of adenosine or its metabolites into the bathing solution across the basolateral membrane.

Barfuss, D.W.; McCann, W.P.; Katholi, R.E.

1986-03-01

431

Proximate bases of silver color in anhinga (Anhinga anhinga) feathers.  

PubMed

Colors of living organisms are produced by selective light absorption from pigments and/or by light scattering from highly ordered nanostructures (i.e., structural color). While the physical bases of metallic colors of arthropods and fish are fairly well-known, those of birds are not. Here we examine structurally based silver color and its production in feathers of the waterbird species Anhinga. This achromatic color is distinguished from grey by high specular reflectance, from white by low diffuse reflectance, and from both by high gloss. Light and electron microscopy revealed three modifications of feathers likely leading to silver color. First, proximal barbules were highly elongated and contained glossy black color at their base and white color at their pennulum. Second, this glossy black portion contained a single outer layer of keratin weakly bounded by melanosomes. Finally, the white portion contained a disordered amorphous matrix of keratin and air. Optical analyzes suggest that these structures produce, respectively, glossy black color through thin-film interference and white color through incoherent light scattering. Silver color likely results from the combined reflectance of these adjacent structures. This represents a distinct mechanism for attaining silver colors that may have been partially derived through selection for display, thermoregulation or decreased hydrophobicity. PMID:21755527

Shawkey, Matthew D; Maia, Rafael; D'Alba, Liliana

2011-07-13

432

Characterization of flow pattern past two spheres in proximity  

NASA Astrophysics Data System (ADS)

As a follow-up study of flow-induced forces on two nearby spheres [D. Yoon and K. Yang, Phys. Fluids 19, 098103 (2007)], this paper establishes a systematic characterization of flow pattern past two identical spheres in proximity at Re=300. We consider all possible arrangements of two spheres in terms of the distance between the spheres and the angle inclined with respect to the main flow direction. It turns out that significant changes in shedding characteristics are noticed depending on how the two spheres are positioned. Ten distinct flow patterns are identified in total, and a detailed description is given to each pattern. Collecting all the numerical results obtained, we propose two comprehensive tables, one for flow pattern for each arrangement of the spheres and the other for Strouhal number of the corresponding vortex shedding. The perfect geometrical symmetry implied in the flow configuration allows one to use those tables for any two identical spheres arbitrarily positioned in physical space with respect to the main flow direction.

Yoon, Dong-Hyeog; Yang, Kyung-Soo

2009-07-01

433

Life-like Control for Neural Prostheses: "Proximal Controls Distal".  

PubMed

We describe the model and implementation of the hierarchical hybrid method for controlling of the lower-arm (pronation/supination and elbow flexion/extension) in humans with disabilities. The control follows the strategy found in ablebodied humans where the movement is planned based on the task and the most distal part of the arm; yet, the command starts from the most proximal segment. The controller uses a black box of the movement and relies on temporal and spatial synergies. The driving signals are the shoulder flexion/extension velocity and acceleration, the outputs are four stimulation patterns for the control of elbow flexion/extension and pronation/supination. The operation is discrete at the voluntary and coordination levels, and continuous at the actuator level. The repertoire of movement that were considered was limited to a set of typical daily activities within the normal workspace in the sitting position only. The main application of this control is the therapeutic electrical stimulation in post-stroke hemiplegic patients. PMID:17282052

Popovic, Dejan; Popovic, Mirjana; Sinkjaer, Thomas

2005-01-01

434

A Human Proximity Operations System test case validation approach  

NASA Astrophysics Data System (ADS)

A Human Proximity Operations System (HPOS) poses numerous risks in a real world environment. These risks range from mundane tasks such as avoiding walls and fixed obstacles to the critical need to keep people and processes safe in the context of the HPOS's situation-specific decision making. Validating the performance of an HPOS, which must operate in a real-world environment, is an ill posed problem due to the complexity that is introduced by erratic (non-computer) actors. In order to prove the HPOS's usefulness, test cases must be generated to simulate possible actions of these actors, so the HPOS can be shown to be able perform safely in environments where it will be operated. The HPOS must demonstrate its ability to be as safe as a human, across a wide range of foreseeable circumstances. This paper evaluates the use of test cases to validate HPOS performance and utility. It considers an HPOS's safe performance in the context of a common human activity, moving through a crowded corridor, and extrapolates (based on this) to the suitability of using test cases for AI validation in other areas of prospective application.

Huber, Justin; Straub, Jeremy

435

Prognosis of Patients With Gastric Cancer Who Underwent Proximal Gastrectomy  

PubMed Central

Proximal gastrectomy (PG) has been introduced for patients who are preoperatively diagnosed with early gastric cancer located in the upper third of the stomach. In the present study, we compared the prognosis of patients who underwent PG with that of patients who underwent total gastrectomy (TG). Between 1997 and 2006, 51 patients were diagnosed with early gastric cancer located in the upper third of the stomach and underwent PG. In the same period, 35 patients were diagnosed with early gastric cancer and underwent TG. Of these, in 24 patients, the cancer was localized in the middle to upper part of the stomach, and 11 patients had multiple cancers. We compared the clinicopathologic differences and prognoses between the two groups. Significantly fewer lymph nodes were dissected in the PG group (mean, 18.2) than in the TG group (mean, 36.6;P < 0.001). Complications were detected in 17.6% of patients in the PG group and in 14.3% of patients in the TG group, which was not significant (P = 0.678). The overall and disease-specific 5-year survival rates in the 51 patients who underwent PG (88.7% and 97.1%, respectively) were not different from those in the 35 patients who underwent TG (87.6% and 93.4%; P = 0.971 and P = 0.553; respectively). These findings indicate that PG can be performed safely and may have various advantages compared with TG in terms of patients' daily lives.

Ikeguchi, Masahide; Kader, Abdul; Takaya, Seigo; Fukumoto, Youji; Osaki, Tomohiro; Saito, Hiroaki; Tatebe, Shigeru; Wakatsuki, Toshiro

2012-01-01

436

Ultrastructural changes in renal proximal tubules after tetraethyllead intoxication  

SciTech Connect

Tetraethyllead (TEL) has been shown to be both an occupational and an environmental hazard to human health. The present study investigates pathological changes in the kidney as a result of TEL poisoning. Rabbits were injected (ip) with 100 to 200 mg TEL, and controls were injected with an equal volume of normal saline solution. Animals were sacrificed upon onset of toxic symptoms (hyperirritation, tremor, and convulsion). Animals were perfused with 2.5% glutaraldehyde. Tissue samples from the renal cortex were obtained for electron microscopy. Pathological changes were not remarkable at the light microscopic level; however, electron microscopic examination revealed marked cytological changes in the epithelial cells of the proximal tubules (PT) of animals treated with TEL. Enlargement of apical vacuoles and accumulation of lysosomes and microbodies were prominent findings in many PT epithelial cells. Many lysosomes appeared to be atypical in nature, displaying a high degree of pleomorphism in size, shape, and density. Giant lysosomes measuring 8 to 10 ..mu..m in diameter and crystalloid bodies within lysosomes were also observed. Configurational changes (increased convolution, branching, vesiculation, and degranulation) of the rough endoplasmic reticulum leading to the formation of honeycomb-like bodies were also found in many PT epithelial cells. The formation of the honeycomb-like bodies may represent a hyperplastic, hypoactive form of the rough endoplasmic reticulum and denotes a disruption of protein synthesis in these cells by TEL.

Chang, L.W. (Univ. of Arkansas for Medical Sciences, Little Rock); Wade, P.R.; Reuhl, K.R.; Olson, M.J.

1980-10-01

437

Dynamic interaction of parallel moving ships in close proximity  

NASA Astrophysics Data System (ADS)

Nowadays, there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions. The hydrodynamic behavior of parallel moving ships in waves is an interesting and important topic of late. A numerical investigation has been carried out for the prediction of wave exciting forces and motion responses of parallel moving ships in regular waves. The numerical solution was based on 3D distribution technique and using the linear wave theory to determine the exciting forces and ship's motion. The speed effects have been considered in the Green function for more realistic results. The numerical computations of wave exciting forces and motion responses were carried out for a Mariner and Series 60 for the purpose of discovering different Froude numbers and different separation distances in head sea conditions. Based on the numerical computations, it was revealed that the sway, roll and yaw have a significant effect due to hydrodynamic interaction.

Islam, M. Rafiqul; Murai, Motohiko

2013-09-01

438

Ultrafast gating of proximity-focused microchannel-plate intensifiers  

SciTech Connect

Proximity-focused, microchannel-plate (MCP) image intensifiers have been used at Los Alamos for many years to allow single frame film and video exposure times in the range of 2.5 to 10 ns. There is now a program to reduce gating times to < 1 ns. This paper reviews previous work and the problems in achieving good resolution with gating times of < 1 ns. The key problems involve applying fast electrical gating signals to the tube elements. We present computer modeling studies of the combined tube, tube connection, and pulser system and show that low photocathode surface resistivity must be obtained to permit fast gating between the photocathode and the MCP input. We discuss ways of making low-resistivity S20 photocathodes, using gallium arsenide photocathodes, and various means of gating the tubes. A variety of pulser designs are being experimentally evaluated including spark gaps, avalanche transistors, Krytron tubes with sharpening gaps, step recovery diodes, and photoconductive elements (PCEs). The results of these studies are presented. Because of the high capacitances involved in most gating schemes, the tube connection geometry must be of low-impedance design, and our solution is presented. Finally, ways of testing these high-speed camera systems are discussed.

Lundy, A.S.; Iverson, A.E.

1982-01-01

439

Collaboration range: Effects of geographical proximity on article impact  

NASA Astrophysics Data System (ADS)

Spatial scientometrics studies how geography influences knowledge creation. In the recent years there has been a surge in this kind of studies, due to the increase of international collaborations. Most of the work in this field has been focused on the geographical distribution of researchers, whilst few have considered how proximity between coauthors influences research quality. In this work we leverage a dataset of geolocalized articles to assess the effect of geographical distance on article impact. More precisely, the dataset, provided by the Observatory of Science and Technology (O.S.T.), consists of roughly 106 scientific articles, gathering all European articles written in 2000 and 2007, spanning 9 disciplines. We evaluate under which geographical extent coauthorships have higher probability of resulting in high impact articles ("high impact" is here approximated by "being in the top 10% most cited articles of its discipline"). We also describe spatial distribution of coauthorship, delineating geographical areas where the production is proportionally higher. The distribution is evaluated both in term of km (as the crow flies), and in terms of administrative partitions (authors' cities, regions, countries).

Apolloni, Andrea; Rouquier, Jean-Baptiste; Jensen, Pablo

2013-09-01

440

Morphological analysis of the proximal femur using quantitative computed tomography  

PubMed Central

The anatomy of the proximal femur was studied in 35 specimens using quantitative computed tomography (QCT) and compared with anatomical sections studied by plane radiography and gross dissection. We found the primary supporting structure of the femoral head to be the primary compressive strut, which is a dense column of trabecular bone projecting from the pressure buttress of the medial femoral neck to the epiphyseal scar. Trabecular bone mushroomed from the epiphyseal scar and terminated at right angles to the cortex of the femoral head. We believe the primary compressive strut is the predominant load-bearing structure connecting the fem