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1

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

2

Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption.  

PubMed

Adenosine type 1 receptor (A1 -AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1 -ARs in the proximal tubule, which is responsible for 60-70% of the reabsorption of filtered Na(+) and fluid. Intratubular application of receptor antagonists indicates that A1 -AR mediates a portion of Na(+) uptake in PT and PT cells, via multiple transport systems, including Na(+) /H(+) exchanger-3 (NHE3), Na(+) /PO4(-) co-transporter and Na(+) -dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1 -AR antagonists and is lower in A1 -AR KO mice, compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1 -AR KO mice, compared to WT mice. Inhibition of A1 -ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

Welch, W J

2015-01-01

3

Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption  

PubMed Central

Adenosine type 1 receptor (A1-AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1-ARs in the proximal tubule, which is responsible for 60–70% of the reabsorption of filtered Na+ and fluid. Intratubular application of receptor antagonists indicates that A1-AR mediates a portion of Na+ uptake in PT and PT cells, via multiple transport systems, including Na+/H+ exchanger-3 (NHE3), Na+/PO4? co-transporter and Na+-dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1-AR antagonists and is lower in A1-AR KO mice., compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1-AR KO mice, compared to WT mice. Inhibition of A1-ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

Welch, William J

2015-01-01

4

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

5

Mechanisms of transjunctional transport of NaCl and water in proximal tubules of mammalian kidneys.  

PubMed

Tight junctions and the intercellular space of proximal tubules are not accessible to direct measurements of fluid composition and transport rates, but morphological and functional data permit analysis of diffusion and osmosis causing transjunctional NaCl and water transport. In the S2 segment NaCl diffuses through tight junctions along a chloride gradient, but against a sodium gradient. Calculation in terms of modified Nernst-Fick diffusion equation after eliminating electrical terms shows that transport rates (300-500 pmol min-1 mm-1 tubule length) and transepithelial voltage of +2 mV are in agreement with observations. Diffusion coefficients are Dtj=1500 microm2 s-1 in the S1 segment, and Dtj=90-100 microm2 s-1 in the S2 segment where apical intercellular NaCl concentration is 132 mM, 1 mM below complete stop (Dtj=0 and Donnan equilibrium). Tight junctions with gap distance 6 A are impermeable to mannitol (effective molecular radius 4 A); reflection coefficients are sigma=0.92 for NaHCO3 and sigma=0.28 for NaCl, because of difference in anion size. The osmotic force is provided by a difference in effective transjunctional osmolality of 10 mOsm kg-1 in the S1 segment and 30 mOsm kg-1 in the S2 segment, where differences in transjunctional concentration contribute with 21 mOsm kg-1 for NaHCO3 and -4 mOsm kg-1 for NaCl. Transjunctional difference of 30 mOsm kg-1 causes a volume flow of 2 nL min-1 mm-1 tubule length. Luminal mannitol concentration of 30 mM stops all volume flow and diffusive and convective transport of NaCl. In conclusion, transjunctional diffusion and osmosis along gradients generated by transcellular transport of other solutes account for all NaCl transport in proximal tubules. PMID:11982505

Kiil, F

2002-05-01

6

Local pH domains regulate NHE3-mediated Na? reabsorption in the renal proximal tubule.  

PubMed

The proximal tubule Na(+)/H(+) exchanger 3 (NHE3), located in the apical dense microvilli (brush border), plays a major role in the reabsorption of NaCl and water in the renal proximal tubule. In response to a rise in blood pressure NHE3 redistributes in the plane of the plasma membrane to the base of the brush border, where NHE3 activity is reduced. This NHE3 redistribution is assumed to provoke pressure natriuresis; however, it is unclear how NHE3 redistribution per se reduces NHE3 activity. To investigate if the distribution of NHE3 in the brush border can change the reabsorption rate, we constructed a spatiotemporal mathematical model of NHE3-mediated Na(+) reabsorption across a proximal tubule cell and compared the model results with in vivo experiments in rats. The model predicts that when NHE3 is localized exclusively at the base of the brush border, it creates local pH microdomains that reduce NHE3 activity by >30%. We tested the model's prediction experimentally: the rat kidney cortex was loaded with the pH-sensitive fluorescent dye BCECF, and cells of the proximal tubule were imaged in vivo using confocal fluorescence microscopy before and after an increase of blood pressure by ?50 mmHg. The experimental results supported the model by demonstrating that a rise of blood pressure induces the development of pH microdomains near the bottom of the brush border. These local changes in pH reduce NHE3 activity, which may explain the pressure natriuresis response to NHE3 redistribution. PMID:25298526

Brasen, Jens Christian; Burford, James L; McDonough, Alicia A; Holstein-Rathlou, Niels-Henrik; Peti-Peterdi, Janos

2014-12-01

7

Solvent drag measurement of transcellular and basolateral membrane NaCl reflection coefficient in kidney proximal tubule  

Microsoft Academic Search

The NaC1 reflection coefficient in proximal tubule has important implications for the mechanisms of near isosmotic volume reabsorption. A new fluorescence method was developed and applied to measure the transepithelial (w~cl) and basolateral membrane (cr~acl) NaCI reflection coefficients in the isolated proximal straight tubule from rabbit kidney. For cr~cl measurement, tubules were perfused with buffers containing 0 C1, the Cl-sensitive

L. B. Shi; KIYOHIDE FUSHIMI; A. S. VERKMAN

1991-01-01

8

Reduction of renal triglyceride accumulation: effects on proximal tubule Na+/H+ exchange and urinary acidification  

PubMed Central

One main pathophysiological mechanism underlying the increased risk for uric acid nephrolithiasis in humans with the metabolic syndrome is the excretion of unduly acidic urine, in part because of reduced excretion of the main urinary buffer, ammonium. The Zucker diabetic fatty (ZDF) rat, an established rodent model of the metabolic syndrome, has similar urinary abnormalities, attributed in part to lower expression and activity of the principal mediator of proximal tubule ammonium excretion, brush-border membrane Na+/H+ exchanger 3 (NHE3). These defects are associated with renal tubular steatosis in ZDF rats, but the causal relationship between renal steatosis and defective urinary acidification has not been investigated in vivo. We hypothesized that reduction of renal steatosis would commensurately normalize urinary acidification parameters. We treated ZDF rats with thiazolidinediones to reduce nonadipose tissue steatosis. Four weeks of treatment reduced renal triglyceride accumulation and restored urinary acidification parameters in ZDF rats to levels comparable to their lean littermates; urinary acidification was not affected by treatment in lean rats. To further document the direct effects of fat, we showed that functional abnormalities induced by fat loading in a cell culture model of proximal tubule steatosis and lipotoxicity can be reversed by fat removal but not by thiazolidinediones alone. Together, these findings support the causative role of renal steatosis in the pathogenesis of urinary acidification defects, demonstrate reversibility upon lipid removal, and highlight a potential therapeutic strategy for renal abnormalities in the metabolic syndrome. PMID:19692486

Bobulescu, I. Alexandru; Dubree, Michele; Zhang, Jianning; McLeroy, Paul

2009-01-01

9

Reduction of renal triglyceride accumulation: effects on proximal tubule Na+/H+ exchange and urinary acidification.  

PubMed

One main pathophysiological mechanism underlying the increased risk for uric acid nephrolithiasis in humans with the metabolic syndrome is the excretion of unduly acidic urine, in part because of reduced excretion of the main urinary buffer, ammonium. The Zucker diabetic fatty (ZDF) rat, an established rodent model of the metabolic syndrome, has similar urinary abnormalities, attributed in part to lower expression and activity of the principal mediator of proximal tubule ammonium excretion, brush-border membrane Na+/H+ exchanger 3 (NHE3). These defects are associated with renal tubular steatosis in ZDF rats, but the causal relationship between renal steatosis and defective urinary acidification has not been investigated in vivo. We hypothesized that reduction of renal steatosis would commensurately normalize urinary acidification parameters. We treated ZDF rats with thiazolidinediones to reduce nonadipose tissue steatosis. Four weeks of treatment reduced renal triglyceride accumulation and restored urinary acidification parameters in ZDF rats to levels comparable to their lean littermates; urinary acidification was not affected by treatment in lean rats. To further document the direct effects of fat, we showed that functional abnormalities induced by fat loading in a cell culture model of proximal tubule steatosis and lipotoxicity can be reversed by fat removal but not by thiazolidinediones alone. Together, these findings support the causative role of renal steatosis in the pathogenesis of urinary acidification defects, demonstrate reversibility upon lipid removal, and highlight a potential therapeutic strategy for renal abnormalities in the metabolic syndrome. PMID:19692486

Bobulescu, I Alexandru; Dubree, Michele; Zhang, Jianning; McLeroy, Paul; Moe, Orson W

2009-11-01

10

Differential regulation of Na+ transporters along nephron during ANG II-dependent hypertension: distal stimulation counteracted by proximal inhibition.  

PubMed

During angiotensin II (ANG II)-dependent hypertension, ANG II stimulates, while hypertension inhibits, Na(+) transporter activity to balance Na(+) output to input. This study tests the hypothesis that ANG II infusion activates Na(+) transporters in the distal nephron while inhibiting transporters along the proximal nephron. Male Sprague-Dawley rats were infused with ANG II (400 ng·kg(-1)·min(-1)) or vehicle for 2 wk. Kidneys were dissected (cortex vs. medulla) or fixed for immunohistochemistry (IHC). ANG II increased mean arterial pressure by 40 mmHg, urine Na(+) by 1.67-fold, and urine volume by 3-fold, evidence for hypertension and pressure natriuresis. Na(+) transporters' abundance and activation [assessed by phosphorylation (-P) or proteolytic cleavage] were measured by immunoblot. During ANG II infusion Na(+)/H(+) exchanger 3 (NHE3) abundance decreased in both cortex and medulla; Na-K-2Cl cotransporter 2 (NKCC2) decreased in medullary thick ascending loop of Henle (TALH) and increased, along with NKCC2-P, in cortical TALH; Na-Cl cotransporter (NCC) and NCC-P increased in the distal convoluted tubule; and epithelial Na(+) channel subunits and their cleaved forms were increased in both cortex and medulla. Like NKCC2, STE20/SPS1-related proline alanine-rich kinase (SPAK) and SPAK-P were decreased in medulla and increased in cortex. By IHC, during ANG II NHE3 remained localized to proximal tubule microvilli at lower abundance, and the differential regulation of NKCC2 and NKCC2-P in cortex versus medulla was evident. In summary, ANG II infusion increases Na(+) transporter abundance and activation from cortical TALH to medullary collecting duct while the hypertension drives a natriuresis response evident as decreased Na(+) transporter abundance and activation from proximal tubule through medullary TALH. PMID:23720346

Nguyen, Mien T X; Lee, Donna H; Delpire, Eric; McDonough, Alicia A

2013-08-15

11

Solvent drag measurement of transcellular and basolateral membrane NaCl reflection coefficient in kidney proximal tubule  

PubMed Central

The NaCl reflection coefficient in proximal tubule has important implications for the mechanisms of near isosmotic volume reabsorption. A new fluorescence method was developed and applied to measure the transepithelial (sigma NaClTE) and basolateral membrane (sigma NaClcl) NaCl reflection coefficients in the isolated proximal straight tubule from rabbit kidney. For sigma NaClTE measurement, tubules were perfused with buffers containing 0 Cl, the Cl-sensitive fluorescent indicator 6- methoxy-N-[3-sulfopropyl] quinolinium and a Cl-insensitive indicator fluorescein sulfonate, and bathed in buffers of differing cryoscopic osmolalities containing NaCl. The transepithelial Cl gradient along the length of the tubule was measured in the steady state by a quantitative ratio imaging technique. A mathematical model based on the Kedem- Katchalsky equations was developed to calculate the axial profile of [Cl] from tubule geometry, lumen flow, water (Pf) and NaCl (PNaCl) permeabilities, and sigma NaClTE. A fit of experimental results to the model gave PNaCl = (2.25 +/- 0.2) x 10(-5) cm/s and sigma NaClTE = 0.98 +/- 0.03 at 23 degrees C. For measurement of sigma NaClbl, tubule cells were loaded with SPQ in the absence of Cl. NaCl solvent drag was measured from the time course of NaCl influx in response to rapid (less than 1 s) Cl addition to the bath solution. With bath-to-cell cryoscopic osmotic gradients of 0, -60, and +30 mosmol, initial Cl influx was 1.23, 1.10, and 1.25 mM/s; a fit to a mathematical model gave sigma NaClbl = 0.97 +/- 0.04. These results indicate absence of NaCl solvent drag in rabbit proximal tubule. The implications of these findings for water and NaCl movement in proximal tubule are evaluated. PMID:1940854

1991-01-01

12

Administration of adrenomedullin into subfornical organ inhibits Na(+),K(+)-ATPase activity in single proximal renal tubule of rats.  

PubMed

The present study was designed to investigate the effect of administration of adrenomedullin (ADM) into subfornical organ (SFO) on renal tubular Na(+),K(+)-ATPase activity in rats. Rats under anesthesia were injected with ADM 0.1 mL (20 ng/mL) via an implanted cannula into SFO (n=6). Plasma ADM and serum endogenous digitalis-like factor (EDLF) levels were assayed with radioimmunoassay, and urine samples were collected via a canoula intubated in bladder. Urinary sodium concentration was assayed with flame spectrophotometry. Single proximal renal tubule segments were obtained by hand under stereomicroscope and its Na(+),K(+)-ATPase activity was measured by liquid scintillation counting. In addition, single proximal renal tubule segments from normal rats (n=6) were incubated with serum from animals administered with ADM into SFO, and then the Na(+),K(+)-ATPase activity was determined. The results showed that both urinary volume and sodium excretion amounted to the peak value at 30 min after ADM administration, and sustained a significant high level at 60 min (P<0.01). At 30 min after ADM administration, there was a significant increase in serum EDLF and a decrease in Na(+),K(+)-ATPase activity of proximal tubule (P<0.01, respectively), but not in plasma ADM level. Na(+),K(+)-ATPase activity was decreased significantly in single proximal renal tubule segments from normal rats incubated with serum from rats administered with ADM into SFO (P<0.01). These results suggest that the diuretic and natriuretic responses following administration of ADM into SFO are associated with the inhibition of renal tubule Na(+),K(+)-ATPase activity. The inhibition of renal tubule Na(+),K(+)-ATPase activity is related to the increase in the serum level of EDLF. PMID:19224060

Gao, Yuan; Li, Xing-Qi

2009-02-25

13

Effect of renal lipid accumulation on proximal tubule Na+/H+ exchange and ammonium secretion  

PubMed Central

Patients with metabolic syndrome have increased risk of uric acid nephrolithiasis due to lower urinary pH and impaired ammonium excretion. The pathophysiology underlying these urinary changes is unknown. We used two animal models and a cell culture model to study whether the alteration in renal acidification is associated with renal fat infiltration (steatosis). Compared with pair-fed lean control rats, Zucker diabetic fatty rats have higher renal triglyceride content, decreased urinary ammonium and pH, and lower levels of brush border membrane Na+/H+ exchanger-3 (NHE3), a major mediator of ammonium excretion. High-fat feeding in Sprague-Dawley rats results in transient lowering of urinary ammonium and pH, with all parameters returning to normal when the animals resumed eating normal chow. This is consistent with an absence of diet-induced renal steatosis in these animals. To examine the direct effect of fat accumulation, we incubated opossum kidney (OKP) cells with a mixture of long-chain fatty acids and found accumulation of intracellular lipids with concomitant dose-dependent decrease in NHE3 activity, surface biotin-accessible NHE3 protein, and ammonium secretion. A lower dose of fatty acids that leads to intracellular lipid accumulation but does not change baseline NHE3 is sufficient to abolish the stimulation of NHE3 by insulin and to partially block the stimulation of NHE3 by glucocorticoid hormones; acid regulation of NHE3 in lipid-loaded OKP cells is not affected. These findings suggest that renal steatosis decreases ammonium secretion in the proximal tubule, in part by reducing NHE3 activity and by impairing the regulation of NHE3 by specific agonists. PMID:18417539

Bobulescu, I. Alexandru; Dubree, Michele; Zhang, Jianning; McLeroy, Paul; Moe, Orson W.

2010-01-01

14

Stimulation of Na/sup +//H/sup +/ antiport is an early event in hypertrophy of renal proximal tubular cells  

SciTech Connect

Renal hypertrophy in vivo is achieved by an increase in protein content per cell and an increase in cell size with minimal hyperplasia. Hypertrophied renal tubular cells remain quiescent and demonstrate an increase in transcellular transport rates. This situation was simulated in vitro by exposing a confluent, quiescent primary culture of rabbit renal proximal tubular cells to either insulin, prostaglandin E/sub 1/, or hypertonic NaCl for 24 or 48 hr. Protein per cell increased by 20-30% with little or no increase in (/sup 3/H)thymidine incorporation into DNA. Mean cell volume was also increased in insulin- and hypertonic NaCl-treated but not in prostaglandin E/sub 1/-treated cells. Two hours of exposure to the growth stimuli increased amiloride-sensitive Na/sup +/ uptake, Na-dependent H/sup +/ efflux, and ouabain-sensitive Rb/sup +/ uptake, indicating that stimulation of Na/sup +//H/sup +/ antiport (exchange) occurs as an early event in their action. Hypertrophied cells continued to demonstrate enhanced Na/sup +//H/sup +/ antiport after the growth stimuli were removed for 3 hr, by which time their acute effects are reversed.

Fine, L.G.; Badie-Dezfooly, B.; Lowe, A.G.; Hamzeh, A.; Wells, J.; Salehmoghaddam, S.

1985-03-01

15

Perinatal Na+ Overload Programs Raised Renal Proximal Na+ Transport and Enalapril-Sensitive Alterations of Ang II Signaling Pathways during Adulthood  

PubMed Central

Background High Na+ intake is a reality in nowadays and is frequently accompanied by renal and cardiovascular alterations. In this study, renal mechanisms underlying perinatal Na+ overload-programmed alterations in Na+ transporters and the renin/angiotensin system (RAS) were investigated, together with effects of short-term treatment with enalapril in terms of reprogramming molecular alterations in kidney. Methodology/Principal Findings Male adult Wistar rats were obtained from dams maintained throughout pregnancy and lactation on a standard diet and drinking water (control) or 0.17 M NaCl (saline group). Enalapril (100 mg/l), an angiotensin converting enzyme inhibitor, was administered for three weeks after weaning. Ninety day old offspring from dams that drank saline presented with proximal tubules exhibiting increased (Na++K+)ATPase expression and activity. Ouabain-insensitive Na+-ATPase activity remained unchanged but its response to angiotensin II (Ang II) was lost. PKC, PKA, renal thiobarbituric acid reactive substances (TBARS), macrophage infiltration and collagen deposition markedly increased, and AT2 receptor expression decreased while AT1 expression was unaltered. Early treatment with enalapril reduced expression and activity of (Na++K+)ATPase, partially recovered the response of Na+-ATPase to Ang II, and reduced PKC and PKA activities independently of whether offspring were exposed to high perinatal Na+ or not. In addition, treatment with enalapril per se reduced AT2 receptor expression, and increased TBARS, macrophage infiltration and collagen deposition. The perinatally Na+-overloaded offspring presented high numbers of Ang II-positive cortical cells, and significantly lower circulating Ang I, indicating that programming/reprogramming impacted systemic and local RAS. Conclusions/Significance Maternal Na+ overload programmed alterations in renal Na+ transporters and in its regulation, as well as severe structural lesions in adult offspring. Enalapril was beneficial predominantly through its influence on Na+ pumping activities in adult offspring. However, side effects including down-regulation of PKA, PKC and AT2 receptors and increased TBARS could impair renal function in later life. PMID:22928034

Cabral, Edjair V.; Vieira-Filho, Leucio D.; Silva, Paulo A.; Nascimento, Williams S.; Aires, Regina S.; Oliveira, Fabiana S. T.; Luzardo, Ricardo; Vieyra, Adalberto; Paixão, Ana D. O.

2012-01-01

16

Plasma potassium concentration as a determinant of proximal tubular NaCl and NaHCO3 reabsorption in dog kidneys.  

PubMed

To examine whether an acute increase in plasma potassium concentration ([K]p) may inhibit proximal tubular transport, clearance studies were performed in seven anaesthetized, volume expanded dogs treated with amiloride (1 mg kg-1 body wt) to block tubular potassium secretion, and with bumetanide (30 micrograms kg-1 body wt) to inhibit NaCl reabsorption in Henle's loop. As [K]p was raised in steps from 2.6 +/- 0.2 to 7.9 +/- 0.2 mM, bicarbonate, chloride, and sodium reabsorption decreased by 232 +/- 56, 520 +/- 59 and 958 +/- 112 mumol min-1, respectively, at constant glomerular filtration rate (GFR). On average, the molar ratio between the inhibitory effects on bicarbonate and chloride reabsorption were 1:2.2-2.4. Reabsorption was calculated at GFR 100 ml min-1: (reabsorption 100/GFR (mmol min-1). It was inversely correlated to ln [K]p with r = -0.82 for bicarbonate and with r = -0.89 for chloride. Fractional potassium reabsorption remained constant at 0.31 +/- 0.03. Administration of acetazolamide (100 mg kg-1 body wt) in eight dogs at [K]p 8 mM reduced fractional reabsorption of bicarbonate, chloride and sodium as much as in previous studies on normokalaemic dogs. We conclude that acute elevation of [K]p inhibits NaHCO3 transport and passive proximal tubular NaCl reabsorption. This inhibition is not related to changes in potassium secretion and carbonic anhydrase activity, but may be secondary to depolarization of the basolateral membrane. PMID:8392774

Stokke, E S; Naess, P A; Ostensen, J; Langberg, H C; Kiil, F

1993-05-01

17

Estrogen directly and specifically downregulates NaPi-IIa through the activation of both estrogen receptor isoforms (ER? and ER?) in rat kidney proximal tubule.  

PubMed

We have previously demonstrated that estrogen (E2) downregulates phosphate transporter NaPi-IIa and causes phosphaturia and hypophosphatemia in ovariectomized rats. In the present study, we examined whether E2 directly targets NaPi-IIa in the proximal tubule (PT) and studied the respective roles of estrogen receptor isoforms (ER? and ER?) in the downregulation of NaPi-IIa using both in vivo and an in vitro expression systems. We found that estrogen specifically downregulates NaPi-IIa but not NaPi-IIc or Pit2 in the kidney cortex. Proximal tubules incubated in a "shake" suspension with E2 for 24 h exhibited a dose-dependent decrease in NaPi-IIa protein abundance. Results from OVX rats treated with specific agonists for either ER? [4,4',4?;-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, PPT] or ER? [4,4',4?-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, DPN] or both (PPT + DPN), indicated that only the latter caused a sharp downregulation of NaPi-IIa, along with significant phosphaturia and hypophosphatemia. Lastly, heterologous expression studies demonstrated that estrogen downregulated NaPi-IIa only in U20S cells expressing both ER? and ER?, but not in cells expressing either receptor alone. In conclusion, these studies demonstrate that rat PT cells express both ER? and ER? and that E2 induces phosphaturia by directly and specifically targeting NaPi-IIa in the PT cells. This effect is mediated via a mechanism involving coactivation of both ER? and ER?, which likely form a functional heterodimer complex in the rat kidney proximal tubule. PMID:25608964

Burris, Dara; Webster, Rose; Sheriff, Sulaiman; Faroqui, Rashma; Levi, Moshe; Hawse, John R; Amlal, Hassane

2015-03-15

18

Role of adenosine triphosphate (ATP) and NaK ATPase in the inhibition of proximal tubule transport with intracellular cystine loading.  

PubMed

Cellular cystine loading with cystine dimethyl ester inhibits volume absorption, transepithelial potential difference, glucose transport, and bicarbonate transport in proximal convoluted tubules perfused in vitro. This study examined the roles of ATP and NaK ATPase in this in vitro model of the Fanconi syndrome of cystinosis. Intracellular ATP was measured using the luciferin-luciferase assay. Intracellular ATP was reduced by 60% in proximal convoluted tubules incubated with 0.5 mM cystine dimethyl ester for 15 min at 37 degrees C (P less than 0.001). Incubation of cystine loaded tubules with 1 mM exogenous ATP increased intracellular ATP to levels not significantly different than that of controls. On the other hand, Vmax NaK ATPase activity was unchanged even though the incubation times and the concentration of cystine dimethyl ester were doubled to 30 min and 1 mM, respectively. In proximal convoluted tubules perfused in vitro, 0.5 mM cystine dimethyl ester resulted in an 89% inhibition in volume absorption (0.81 +/- 0.14 to 0.09 +/- 0.09 nl/mm.min), while there was only a 45% inhibition in volume absorption (P less than 0.01) due to cellular cystine loading in the presence of 1 mM lumen and bath ATP (0.94 +/- 0.05 to 0.52 +/- 0.11 nl/mm.min). These data demonstrate that proximal tubule cellular cystine loading decreases cellular ATP concentration, but does not directly inhibit NaK ATPase activity. The inhibition in transport and decrease in intracellular ATP due to cellular cystine loading was ameliorated by exogenous ATP. These data are consistent with cellular ATP depletion playing a major role in the inhibition of proximal tubule transport due to intracellular cystine loading. PMID:1847941

Coor, C; Salmon, R F; Quigley, R; Marver, D; Baum, M

1991-03-01

19

Regulation of Na-K-ATPase Activity in the Proximal Tubule: Role of the Protein Kinase C Pathway and of Eicosanoids  

Microsoft Academic Search

.   To evaluate further the signal transduction mechanisms involved in the short-term modulation of Na-K-ATPase activity in the\\u000a mammalian kidney, we examined the role of phospholipase C-protein kinase C (PLC-PKC) pathway and of various eicosanoids in\\u000a this process, using microdissected rat proximal convoluted tubules. Dopamine (DA) and parathyroid hormone (either synthetic\\u000a PTH1-34 or PTH3-34) inhibited Na-K-ATPase activity in dose-dependent manner;

M. Ominato; T. Satoh; A. I. Katz

1996-01-01

20

Effects of Acetazolamide on Proximal Tubule Cl, Na, and HCO3 Transport in Normal and Acidotic Dogs during Distal Blockade  

PubMed Central

It has been suggested that the establishment of a tubular fluid to plasma chloride gradient in the late proximal tubule by the reabsorption of bicarbonate (and other anions) in the early proximal tubule is responsible for a significant part of sodium chloride and water reabsorption in the proximal tubule. In the present study the effects of acetazolamide on proximal tubule water and electrolyte excretion were examined in 6 normal dogs and 10 chronic ammonium chloride-loaded dogs during distal blockade produced by ethacrynic acid and chlorothiazide administration. During distal blockade control urine/plasma osmolality and urine/plasma sodium were close to unity in all experiments. Urine/plasma chloride and urine/plasma bicarbonate were 1.21±0.02 and 0.75±0.07 in normal and 1.24±0.01 and 0.04±0.01 in acidotic dogs, respectively. After the administration of acetazolamide (20 mg/kg i.v.), there was a significant increase in urine flow, absolute and fractional excretion of sodium, bicarbonate, and chloride in all animals. Associated with these effects, urine/plasma osmolality and urine/plasma sodium remained unchanged but urine/plasma chloride decreased significantly to 1.15±0.01 in normal and to 1.19±0.01 in acidotic dogs. In acidotic dogs there was a significant correlation between the increase in bicarbonate, sodium, or chloride excretion after acetazolamide and the plasma bicarbonate level (range 6.8-12.5 meq/liter). These data demonstrate a significant effect of acetazolamide on bicarbonate, sodium, and chloride reabsorption in the proximal tubule even in the face of severe acidosis. Moreover, the data suggest that the decrease in chloride reabsorption (and accompanying sodium) after acetazolamide is related to the decrease in bicarbonate reabsorption and the associated decrease in the transtubular chloride gradient. PMID:874081

Chou, Shyan-Yih; Porush, Jerome G.; Slater, Paul A.; Flombaum, Carlos D.; Shafi, Tahir; Fein, Paul A.

1977-01-01

21

The carbohydrate moieties of the beta-subunit of Na+, K(+)-ATPase: their lateral motions and proximity to the cardiac glycoside site.  

PubMed Central

The beta-subunit associated with the catalytic (alpha) subunit of the mammalian Na+, K(+) -ATPase is a transmembrane glycoprotein with three extracellularly located N-glycosylation sites. Although beta appears to be essential for a functional enzyme, the role of beta and its sugars remains unknown. In these studies, steady-state and dynamic fluorescence measurements of the fluorophore lucifer yellow (LY) covalently linked to the carbohydrate chains of beta have demonstrated that the bound probes are highly solvent exposed but restricted in their diffusional motions. Furthermore, the probes' environments on beta were not altered by Na+ or K+ or ouabain-induced enzyme conformational changes, but both divalent cation and oligomycin addition evoked modest changes in LY fluorescence. Frequency domain measurements reflecting the Förster fluorescence energy transfer (FET) occurring between anthroylouabain (AO) bound to the cardiac glycoside receptor site on alpha and the carbohydrate-linked LY demonstrated their close proximity (18 A). Additional FET determinations made between LY as donor and erythrosin-5-isothiocyanate, covalently bound at the enzyme's putative ATP binding site domain, indicated that a distance of about 85 A separates these two regions and that this distance is reduced upon divalent cation binding and increased upon the Na+E1-->K+E2 conformational transition. These data suggest a model for the localization of the terminal moieties of the oligosaccharides that places them, on average, about 18 A from the AO binding site and this distance or less from the extracellular membrane surface. Images FIGURE 5 PMID:8770197

Amler, E; Abbott, A; Malak, H; Lakowicz, J; Ball, W J

1996-01-01

22

BSC-1 growth inhibitor transforms a mitogenic stimulus into a hypertrophic stimulus for renal proximal tubular cells: relationship to Na/sup +//H/sup +/ antiport activity  

SciTech Connect

Renal hypertrophy is characterized by an increase in cell size and protein content with minimal hyperplasia. The mechanisms of control of this pattern of cell growth have not been determined. The present studies examined whether the growth inhibitor elaborated by BSC-1 kidney epilethal cells (GI), which has nearly identical biological properties to transforming growth factor ..beta.. (TGF-..beta..), could transform a mitogenic stimulus into a hypertrophic stimulus for rabbit renal proximal tubular cells in primary culture. Insulin plus hydrocortisone increased the amount of protein per cell, cell volume, and (/sup 3/H)thymidine incorporation at 24 and 48 hr in these cells. When added together with insulin plus hydrocortisone, GI/TGF-..beta.. inhibited the stimulatory effect of these mitogens on (/sup 3/H)thymidine incorporation but did not block the increase in protein per cell and cell volume - i.e., the cells underwent hypertrophy. The fact that this pattern persisted for 48 hr indicated that GI/TGF-..beta.. exerted a prolonged inhibitory effect on mitogenic-stimulated DNA synthesis rather than delaying its onset. Amiloride-sensitive Na/sup +/ uptake using /sup 22/Na/sup +/ as a tracer, correlated with protein per cell and cell volume rather than with DNA synthesis. These studies indicate that the control of cell size may be regulated by autocrine mechanisms mediated by the elaboration of growth inhibitory factors that alter the pattern of the growth response to mitogens.

Fine, L.G.; Holley, R.W.; Nasri, H.; Badie-Dezfooly, B.

1985-09-01

23

Proximal Nephron  

PubMed Central

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.

2013-01-01

24

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

25

Functional role of glucose metabolism, osmotic stress, and sodium-glucose cotransporter isoform-mediated transport on Na+/H+ exchanger isoform 3 activity in the renal proximal tubule.  

PubMed

Na(+)-glucose cotransporter 1 (SGLT1)-mediated glucose uptake leads to activation of Na(+)-H(+) exchanger 3 (NHE3) in the intestine by a process that is not dependent on glucose metabolism. This coactivation may be important for postprandial nutrient uptake. However, it remains to be determined whether SGLT-mediated glucose uptake regulates NHE3-mediated NaHCO3 reabsorption in the renal proximal tubule. Considering that this nephron segment also expresses SGLT2 and that the kidneys and intestine show significant variations in daily glucose availability, the goal of this study was to determine the effect of SGLT-mediated glucose uptake on NHE3 activity in the renal proximal tubule. Stationary in vivo microperfusion experiments showed that luminal perfusion with 5 mM glucose stimulates NHE3-mediated bicarbonate reabsorption. This stimulatory effect was mediated by glycolytic metabolism but not through ATP production. Conversely, luminal perfusion with 40 mM glucose inhibited NHE3 because of cell swelling. Notably, pharmacologic inhibition of SGLT activity by Phlorizin produced a marked inhibition of NHE3, even in the absence of glucose. Furthermore, immunofluorescence experiments showed that NHE3 colocalizes with SGLT2 but not SGLT1 in the rat renal proximal tubule. Collectively, these findings show that glucose exerts a bimodal effect on NHE3. The physiologic metabolism of glucose stimulates NHE3 transport activity, whereas, supraphysiologic glucose concentrations inhibit this exchanger. Additionally, Phlorizin-sensitive SGLT transporters and NHE3 interact functionally in the proximal tubule. PMID:24652792

Pessoa, Thaissa Dantas; Campos, Luciene Cristina Gastalho; Carraro-Lacroix, Luciene; Girardi, Adriana C C; Malnic, Gerhard

2014-09-01

26

Proximity fuze  

Microsoft Academic Search

A proximity fuze system is described. It includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation circuit. 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

1989-01-01

27

Proximity fuze  

Microsoft Academic Search

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

Thomas R

1989-01-01

28

Proximity fuze  

Microsoft Academic Search

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 circuit. 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

1987-01-01

29

Phosphorylation of Ser982 in the sodium bicarbonate cotransporter kNBC1 shifts the HCO3?: Na+ stoichiometry from 3:1 to 2:1 in murine proximal tubule cells  

PubMed Central

Adenosine 3?,5?-cyclic monophosphate (cAMP) modulates proximal tubule sodium and bicarbonate absorption by decreasing the rate of apical Na+-H+ exchange and basolateral sodium bicarbonate efflux, through activation of protein kinase A (PKA). The electrogenic sodium bicarbonate cotransporter kNBC1 mediates basolateral sodium and bicarbonate efflux in the proximal tubule by coupling the transport of 1 Na+ cation to that of 3 HCO3? anions. In this work we studied the effects of cAMP on the function of kNBC1 expressed heterologously in a proximal tubule cell line. A mouse renal proximal tubule cell line, deficient in electrogenic sodium bicarbonate cotransport function, was transfected with kNBC1. Cells were grown on a permeable support to confluence, mounted in an Ussing chamber and permeabilized apically with amphotericin B. Current through the cotransporter was isolated as the difference current due to the reversible inhibitor dinitrostilbene disulfonate. The HCO3?:Na+ stoichiometry of kNBC1 was calculated from its reversal potential by measuring the current-voltage relationships of the cotransporter at different Na+ concentration gradients. Addition of the potent cAMP agonsit 8-Br-cAMP caused the stoichiometry of kNBC1 to shift from 3 HCO3?: 1 Na+ to 2 HCO3?:1 Na+. Pretreatment of the cells with the PKA inhibitor H-89 abolished the effect of the agonist on the stoichiometry change. Replacing Ser982 at the C-terminus consensus PKA phosphorylation site with alanine resulted in a failure of PKA to phosphorylate the transporter and induce a stoichiometry shift. Our data indicate that cAMP modulates the stoichiometry of kNBC1 through activation of PKA. The change in stoichiometry from 3:1 to 2:1 is predicted to cause a shift in the direction of basolateral membrane sodium bicarbonate transport from efflux to influx. Ser982 in the C-terminus of kNBC1 is a target for PKA phosphorylation. This is the first example of modulation of the stoichiometry of a membrane transporter by phosphorylation. PMID:11744745

Gross, E; Hawkins, K; Pushkin, A; Sassani, P; Dukkipati, R; Abuladze, N; Hopfer, U; Kurtz, I

2001-01-01

30

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

31

Proximity fuze  

SciTech Connect

A proximity fuze system is described. It includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation circuit. 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 from the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation.

Harrison, T.R.

1989-08-22

32

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 circuit. 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 from the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation. 3 figs.

Harrison, T.R.

1987-07-10

33

Role of H{sub 2}O{sub 2} on the kinetics of low-affinity high-capacity Na{sup +}-dependent alanine transport in SHR proximal tubular epithelial cells  

SciTech Connect

Research highlights: {yields} H{sub 2}O{sub 2} in excess is required for the presence of a low-affinity high-capacity component for the Na{sup +}-dependent [{sup 14}C]-L-alanine uptake in SHR PTE cells only. {yields} It is suggested that Na{sup +} binding in renal ASCT2 may be regulated by ROS in SHR PTE cells. -- Abstract: The presence of high and low sodium affinity states for the Na{sup +}-dependent [{sup 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{sub 2}O{sub 2} on the Na{sup +}-dependent [{sup 14}C]-L-alanine uptake of ASCT2 in immortalized renal PTE cells from Wistar Kyoto rat (WKY) and spontaneously hypertensive rat (SHR). Na{sup +} dependence of [{sup 14}C]-L-alanine uptake was investigated replacing NaCl with an equimolar concentration of choline chloride in vehicle- and apocynin-treated cells. Na{sup +} removal from the uptake solution abolished transport activity in both WKY and SHR PTE cells. Decreases in H{sub 2}O{sub 2} levels in the extracellular medium significantly reduced Na{sup +}-K{sub m} and V{sub 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{sup +}-dependent [{sup 14}C]-L-alanine uptake. After removal of apocynin from the culture medium, H{sub 2}O{sub 2} levels returned to basal values within 1 to 3 h in both WKY and SHR PTE cells and these were found stable for the next 24 h. Under these experimental conditions, the Na{sup +}-K{sub m} and V{sub max} of the high-affinity low-capacity state were unaffected and the low-affinity high-capacity component remained significantly decreased 1 day but not 4 days after apocynin removal. In conclusion, H{sub 2}O{sub 2} in excess is required for the presence of a low-affinity high-capacity component for the Na{sup +}-dependent [{sup 14}C]-L-alanine uptake in SHR PTE cells only. It is suggested that Na{sup +} binding in renal ASCT2 may be regulated by ROS in SHR PTE cells.

Pinto, Vanda; Pinho, Maria Joao [Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-319 Porto (Portugal)] [Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-319 Porto (Portugal); Jose, Pedro A. [Center for Molecular Physiology Research, Children's National Medical Center, Department of Pediatrics, George Washington School of Medicine and Health Sciences, Washington, DC (United States)] [Center for Molecular Physiology Research, Children's National Medical Center, Department of Pediatrics, George Washington School of Medicine and Health Sciences, Washington, DC (United States); Soares-da-Silva, Patricio, E-mail: pss@med.up.pt [Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-319 Porto (Portugal)] [Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-319 Porto (Portugal)

2010-07-30

34

Substrate specificity of the luminal Na + -dependent sulphate transport system in the proximal renal tubule as compared to the contraluminal sulphate exchange system  

Microsoft Academic Search

The efflux of [35S]sulphate from the lumen of the proximal renal tubule into tubular cells of rats was measured by the stop-flow tubular-lumen microperfusion technique. The transport parameters obtained and the apparent Ki values of competing substrates were compared with those of the contraluminal influx of [35-S]sulphate from the interstitium into tubular cells. For the luminal sulphate efflux a Km(l,

C. David; K. J. Ullrich

1992-01-01

35

Antagonistic actions of renal dopamine and 5-hydroxytryptamine: increase in Na+, K(+)-ATPase activity in renal proximal tubules via activation of 5-HT1A receptors.  

PubMed Central

1. 5-Hydroxytryptamine (5-HT) is antinatriuretic. Since this effect of 5-HT is not accomplished by changes in glomerular haemodynamics, we have examined in this study whether 5-HT may influence sodium excretion by affecting the Na+, K(+)-ATPase activity in renal cortical tubules. 2. Na+, K(+)-ATPase activity was determined as the rate of [32P]-ATP hydrolysis in renal cortical tubules in suspension. Basal Na+, K(+)-ATPase activity in renal tubules was 4.8 +/- 0.4 mumol Pi mg-1 protein h-1 (n = 8). The 5-HT1A receptor agonist, (+/-)-8-hydroxy-2-(di-n-propylamino) tetraline (8-OH-DPAT) (10 to 3000 nM) induced a concentration-dependent increase (P < 0.05) in Na+, K(+)-ATPase activity with an EC50 value of 355 nM (95% confidence limits: 178, 708). Maximal stimulation elicited by 3000 nM of 8-OH-DPAT was antagonized by the selective 5-HT1A receptor antagonist, (+)-WAY 100135 10 to 1000 nM) with an IC50 value of 20 nM (14, 29); 0.3 microM (+)-WAY 100135 completely abolished (P < 0.01) the stimulatory effect of 8-OH-DPAT. The stimulatory effect of 8-OH-DPAT was found to be time-dependent (15 +/- 2% and 66 +/- 7% increase at 2.5 and 5.0 min, respectively). The 5-HT2 receptor agonist alpha-methyl-5-HT (100 to 3000 nM) did not induce any significant changes in Na+, K(+)-ATPase activity (5.0 +/- 1.5 mumol Pi mg-1 protein h-1; n = 4). 3. The stimulatory effect 8-OH-DPAT was absent when homogenates were used. Stimulation occurred at a Vmax concentration (70 mM) of sodium supporting the notion that stimulation occurs independently of increasing sodium permeability. 4. The inhibitory effect of dopamine (P < 0.05) on Na+, K(+)-ATPase activity was blunted by co-incubation with 8-OH-DPAT (0.5 microM). 5. It is concluded that activation of 5-HT1A receptors increases Na+, K(+)-ATPase activity in renal cortical tubules; this effect may represent an important cellular mechanism, at the tubule level, responsible for the antinatriuretic effect of 5-HT. Images Figure 4 PMID:8882616

Soares-da-Silva, P.; Pinto-do-O, P. C.; Bertorello, A. M.

1996-01-01

36

Inhibitory effect of ETB receptor on Na(+)-K(+) ATPase activity by extracellular Ca(2+) entry and Ca(2+) release from the endoplasmic reticulum in renal proximal tubule cells.  

PubMed

The kidney is important in the long-term regulation of blood pressure and sodium homeostasis. Stimulation of ETB receptors in the kidney increases sodium excretion, in part, by decreasing sodium transport in the medullary thick ascending limb of Henle and in collecting duct. However, the role of ETB receptor on Na(+)-K(+) ATPase activity in renal proximal tubule (RPT) cells is not well defined. The purpose of this study is to test the hypothesis that ETB receptor inhibits Na(+)-K(+) ATPase activity in rat RPT cells, and investigate the mechanism(s) by which such an action is produced. In RPT cells from Wistar-Kyoto rats, stimulation of ETB receptors by the ETB receptor agonist, BQ3020, decreased Na(+)-K(+) ATPase activity, determined by ATP hydrolysis (control=0.38+/-0.02, BQ3020=0.26+/-0.03, BQ788=0.40+/-0.06, BQ3020+BQ788=0.37+/-0.04, n=5, P<0.01). The ETB receptor-mediated inhibition of Na(+)-K(+) ATPase activity was dependent on an increase in intracellular calcium, because this effect was abrogated by a chelator of intracellular-free calcium (BAPTA-AM; 5 x 10(-3) M 15 min(-1)), Ca(2+) channel blocker (10(-6) M 15 min(-1) nicardipine) and PI3 kinase inhibitor (10(-7) M per wortmannin). An inositol 1,4,5-trisphosphate (IP3) receptor blocker (2-aminoethyl diphenyl borate; 10(-4) M 15 min(-1)) also blocked the inhibitory effect of the ETB receptor on Na(+)-K(+)ATPase activity (control=0.39+/-0.06, BQ3020=0.25+/-0.01, 2-APB=0.35+/-0.05, BQ3020+ 2-APB=0.35+/-0.06, n=4, P<0.01). The calcium channel agonist (BAY-K8644; 10(-6) M 15 min(-1)) inhibited Na(+)-K(+) ATPase activity, an effect that was blocked by a phosphatidylinositol-3 kinase inhibitor (10(-7) M 15 min(-1) wortmannin). In rat RPT cells, activation of the ETB receptor inhibits Na(+)-K(+) ATPase activity by facilitating extracellular Ca(2+) entry and Ca(2+) release from endoplasmic reticulum. PMID:19662022

Liu, Yan; Yang, Jian; Ren, Hongmei; He, Duofen; Pascua, Annabelle; Armando, M Ines; Yang, Chengming; Zhou, Lin; Felder, Robin A; Jose, Pedro A; Zeng, Chunyu

2009-10-01

37

Inhibitory effect of ETB receptor on Na+–K+ ATPase activity by extracellular Ca2+ entry and Ca2+ release from the endoplasmic reticulum in renal proximal tubule cells  

PubMed Central

The kidney is important in the long-term regulation of blood pressure and sodium homeostasis. Stimulation of ETB receptors in the kidney increases sodium excretion, in part, by decreasing sodium transport in the medullary thick ascending limb of Henle and in collecting duct. However, the role of ETB receptor on Na+–K+ ATPase activity in renal proximal tubule (RPT) cells is not well defined. The purpose of this study is to test the hypothesis that ETB receptor inhibits Na+–K+ ATPase activity in rat RPT cells, and investigate the mechanism(s) by which such an action is produced. In RPT cells from Wistar–Kyoto rats, stimulation of ETB receptors by the ETB receptor agonist, BQ3020, decreased Na+–K+ ATPase activity, determined by ATP hydrolysis (control=0.38±0.02, BQ3020=0.26±0.03, BQ788=0.40±0.06, BQ3020+BQ788=0.37±0.04, n=5, P<0.01). The ETB receptor-mediated inhibition of Na+–K+ ATPase activity was dependent on an increase in intracellular calcium, because this effect was abrogated by a chelator of intracellular-free calcium (BAPTA-AM; 5×10?3 m 15 min?1), Ca2+ channel blocker (10?6 m 15 min?1 nicardipine) and PI3 kinase inhibitor (10?7 m per wortmannin). An inositol 1,4,5-trisphosphate (IP3) receptor blocker (2-aminoethyl diphenyl borate; 10?4 m 15 min?1) also blocked the inhibitory effect of the ETB receptor on Na+–K+ ATPase activity (control=0.39±0.06, BQ3020=0.25±0.01, 2-APB=0.35±0.05, BQ3020+ 2-APB=0.35±0.06, n=4, P<0.01). The calcium channel agonist (BAY-K8644; 10?6 m 15 min?1) inhibited Na+–K+ ATPase activity, an effect that was blocked by a phosphatidylinositol-3 kinase inhibitor (10?7 m 15 min?1 wortmannin). In rat RPT cells, activation of the ETB receptor inhibits Na+–K+ ATPase activity by facilitating extracellular Ca2+ entry and Ca2+ release from endoplasmic reticulum. PMID:19662022

Liu, Yan; Yang, Jian; Ren, Hongmei; He, Duofen; Pascua, Annabelle; Armando, M Ines; Yang, Chengming; Zhou, Lin; Felder, Robin A; Jose, Pedro A; Zeng, Chunyu

2010-01-01

38

Proteinases inhibit H(+)-ATPase and Na+/H+ exchange but not water transport in apical and endosomal membranes from rat proximal tubule.  

PubMed

A marked increase in water permeability can be induced in Xenopus oocytes by injection of mRNA from tissues that express water channels, suggesting that the water channel is a protein. In view of this and previous reports which showed that proteinases may interfere with mercurial inhibition of water transport in red blood cells (RBC), we examined the influence of trypsin, chymotrypsin, papain, pronase, subtilisin and thermolysin on water permeability as well as on ATPase activity, H(+)-pump, passive H+ conductance, and Na+/H+ exchange in apical brush-border vesicles (BBMV) and endosomal (EV) vesicles from rat renal cortex. H+ transport was measured by Acridine orange fluorescence quenching and water transport by stopped-flow light scattering. As measured by potential-driven H+ accumulation in BBMV and EV, proteinase treatment had little effect on vesicle integrity. In BBMV, ecto-ATPase activity was inhibited by 15-30%, Na+/H+ exchange by 20-55%, and H+ conductance was unchanged. Osmotic water permeability (Pf) was 570 microns/s and was inhibited 85-90% by 0.6 mM HgCl2; proteinase treatment did not affect Pf or the HgCl2 inhibition. In EV, NEM-sensitive H+ accumulation and ATPase activity were inhibited by greater than 95%. Pf (140 microns/s) and HgCl2 inhibition (75-85%) were not influenced by proteinase treatment. SDS-PAGE showed selective digestion of multiple polypeptides by proteinases. These results confirm the presence of water channels in BBMV and EV and demonstrate selective inhibition of ATPase function and Na+/H+ exchange by proteinase digestion. The lack of effect of proteinases on water transport by mercurials. We conclude that the water channel may be a small integral membrane protein which, unlike the H(+)-ATPase and Na+/H+ exchanger, has no functionally important membrane domains that are sensitive to proteolysis. PMID:1309658

Saboli?, I; Shi, L B; Brown, D; Ausiello, D A; Verkman, A S

1992-01-10

39

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

40

Androgens augment proximal tubule transport.  

PubMed

The proximal tubule contains an autonomous renin-angiotensin system that regulates transport independently of circulating angiotensin II. Androgens are known to increase expression of angiotensinogen, but the effect of androgens on proximal tubule transport is unknown. In this in vivo microperfusion study, we examined the effect of androgens on proximal tubule transport. The volume reabsorptive rate in Sprague-Dawley rats given dihydrotestosterone (DHT) injections was significantly higher than in control rats given vehicle injections (4.57 +/- 0.31 vs. 3.31 +/- 0.23 nl x min(-1) x mm(-1), P < 0.01). Luminally perfusing with either enalaprilat (10(-4) M) to inhibit production of angiotensin II or losartan (10(-8) M) to block the angiotensin receptor decreased the proximal tubule volume reabsorptive rate in DHT-treated rats to a significantly greater degree than in control vehicle-injected rats. The renal expression of angiotensinogen was shown to be higher in the DHT-treated animals, using Northern blot analysis. The expression of angiotensin receptors, determined by specific binding of angiotensin II, was not different in the two groups of animals. Brush-border membrane protein abundance of the Na/H exchanger, a membrane transport protein under angiotensin II regulation, was also higher in DHT-treated rats vs. control rats. Rats that received DHT had higher blood pressures than the control rats but had no change in their glomerular filtration rate. In addition, serum angiotensin II levels were lower in DHT-treated vs. control rats. These results suggest that androgens may directly upregulate the proximal tubule renin-angiotensin system, increase the volume reabsorptive rate, and thereby increase extracellular volume and blood pressure and secondarily decrease serum angiotensin II levels. PMID:15100096

Quan, Albert; Chakravarty, Sumana; Chen, Jian-Kang; Chen, Jian-Chun; Loleh, Samer; Saini, Neel; Harris, Ray C; Capdevila, Jorge; Quigley, Raymond

2004-09-01

41

Bachelor Project Proximity Alert  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.3.3 Box-Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.3.4 Proximity Alert Metric and Box-Plot . . . . . . . . . . . . . . . . . . . 21 4.4 Views

Lanza, Michele

42

Proximal Tubule Function and Response to Acidosis  

PubMed Central

Summary The human kidneys produce approximately 160–170 L of ultrafiltrate per day. The proximal tubule contributes to fluid, electrolyte, and nutrient homeostasis by reabsorbing approximately 60%–70% of the water and NaCl, a greater proportion of the NaHCO3, and nearly all of the nutrients in the ultrafiltrate. The proximal tubule is also the site of active solute secretion, hormone production, and many of the metabolic functions of the kidney. This review discusses the transport of NaCl, NaHCO3, glucose, amino acids, and two clinically important anions, citrate and phosphate. NaCl and the accompanying water are reabsorbed in an isotonic fashion. The energy that drives this process is generated largely by the basolateral Na+/K+-ATPase, which creates an inward negative membrane potential and Na+-gradient. Various Na+-dependent countertransporters and cotransporters use the energy of this gradient to promote the uptake of HCO3? and various solutes, respectively. A Na+-dependent cotransporter mediates the movement of HCO3? across the basolateral membrane, whereas various Na+-independent passive transporters accomplish the export of various other solutes. To illustrate its homeostatic feat, the proximal tubule alters its metabolism and transport properties in response to metabolic acidosis. The uptake and catabolism of glutamine and citrate are increased during acidosis, whereas the recovery of phosphate from the ultrafiltrate is decreased. The increased catabolism of glutamine results in increased ammoniagenesis and gluconeogenesis. Excretion of the resulting ammonium ions facilitates the excretion of acid, whereas the combined pathways accomplish the net production of HCO3? ions that are added to the plasma to partially restore acid-base balance. PMID:23908456

2014-01-01

43

Proximal Tibial Bone Graft  

MedlinePLUS

Injections and other Procedures Treatments of the Ankle Treatments of the Big Toe Treatments of the Heel Treatments of the Midfoot Treatments of the Smaller Toes AOFAS / FootCareMD / Treatments Proximal Tibial ...

44

Proximal interphalangeal joint sprains.  

PubMed

We report the first series of proximal interphalangeal joint sprains and reviewed 50 sprains in 48 patients. The majority of patients were males injured at work. The radial collateral ligament was injured about twice as often as the ulnar ligaments. The little finger was injured significantly less than the others. Proximal interphalangeal joint sprains can be diagnosed by the following: pain localized to the injured ligament, swelling greatest at the site of the injured ligament, tenderness greatest at the site of the injured ligament, pain at the site of the injured ligament during lateral stress, and/or mild lateral instability on radiographs or physical examination during stress testing. All patients required several different splints for treatment; in decreasing frequency, we used immobilizing, coupling, dynamic proximal interphalangeal flexion, dynamic proximal interphalangeal and distal interphalangeal flexion, and dynamic proximal interphalangeal extension splints. The mean active range of motion before treatment was 70 degrees and after treatment was 95 degrees. Significantly more patients had loss of full extension than had loss of full flexion. Forty-six percent of the patients had no pain after treatment, 46 percent had mild pain, 8 percent had moderate pain, and none had severe pain. Patients treated within 4 weeks of their injury (group 1) gained significantly greater range of motion (35 degrees) than those treated between 5 and 14 weeks after their injury (10 degrees) (group 2).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6739583

Wray, R C; Young, V L; Holtman, B

1984-07-01

45

Proximal fifth metatarsal fractures.  

PubMed

The most common fracture of the foot is a fracture of the proximal fifth metatarsal. In general, there are 3 types of fractures involving the proximal fifth metatarsal area, including a proximal diaphyseal stress fracture, a Jones fracture, and an avulsion fracture of the tuberosity. Some fractures of the fifth metatarsal heal without difficulty, whereas some have the potential for nonunion or delayed healing. Each fracture has some variation in the anatomical location on the fifth metatarsal, the mechanism of injury, the radiographic findings, and the treatment plan. Avulsion fractures of the tuberosity often heal without difficulty, yet fractures distal to the area of insertion of the peroneus brevis tendon are prone to nonunion and delayed healing (). Differential diagnosis of a fifth metatarsal midfoot injury includes ankle sprains, midfoot sprains, plantar facial ruptures, peroneus tendon ruptures, and other foot fractures. PMID:24176827

Ramponi, Denise R

2013-01-01

46

Capacitive proximity sensor  

DOEpatents

A proximity sensor based on a closed field circuit. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change.

Kronberg, James W. (Aiken, SC)

1994-01-01

47

Capacitive proximity sensor  

DOEpatents

A proximity sensor based on a closed field circuit is disclosed. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change. 14 figs.

Kronberg, J.W.

1994-05-31

48

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

49

Subacute diabetic proximal neuropathy  

NASA Technical Reports Server (NTRS)

OBJECTIVE: To evaluate the clinical, electrophysiologic, autonomic, and neuropathologic characteristics and the natural history of subacute diabetic proximal neuropathy and its response to immunotherapy. MATERIAL AND METHODS: For the 12-year period from 1983 to 1995, we conducted a retrospective review of medical records of Mayo Clinic patients with diabetes who had subacute onset and progression of proximal weakness. The responses of treated versus untreated patients were compared statistically. RESULTS: During the designated study period, 44 patients with subacute diabetic proximal neuropathy were encountered. Most patients were middle-aged or elderly, and no sex preponderance was noted. The proximal muscle weakness often was associated with reduced or absent lower extremity reflexes. Associated weight loss was a common finding. Frequently, patients had some evidence of demyelination on nerve conduction studies, but it invariably was accompanied by concomitant axonal degeneration. The cerebrospinal fluid protein concentration was usually increased. Diffuse and substantial autonomic failure was generally present. In most cases, a sural nerve biopsy specimen suggested demyelination, although evidence of an inflammatory infiltrate was less common. Of 12 patients who received treatment (with prednisone, intravenous immune globulin, or plasma exchange), 9 had improvement of their conditions, but 17 of 29 untreated patients (59%) with follow-up also eventually had improvement, albeit at a much slower rate. Improvement was usually incomplete. CONCLUSION: We suggest that the entity of subacute diabetic proximal neuropathy is an extensive and severe variant of bilateral lumbosacral radiculoplexopathy, with some features suggestive of an immune-mediated cause. It differs from chronic inflammatory demyelinating polyradiculoneuropathy in that most cases have a more restricted distribution and seem to be monophasic and self-limiting. The efficacy of immunotherapy is unproved, but such intervention may be considered in the severe and progressive cases or ones associated with severe neuropathic pain.

Pascoe, M. K.; Low, P. A.; Windebank, A. J.; Litchy, W. J.

1997-01-01

50

Proximate analysis of coal  

SciTech Connect

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, fixed carbon, and ash content are determined for each sample and comparisons are made. Proximate analysis is performed on a coal sample from a local electric utility. From the weight percent sulfur found in the coal (determined by a separate procedure the Eschka method) and the ash content, students calculate the quantity of sulfur dioxide emissions and ash produced annually by a large coal-fired electric power plant.

Donahue, C.J.; Rais, E.A. [University of Michigan, Dearborn, MI (USA)

2009-02-15

51

Proximity Networks and Epidemics  

NASA Astrophysics Data System (ADS)

We presented the basis of a framework to account for the dynamics of contacts in epidemic processes, through the notion of dynamic proximity graphs. By varying the integration time-parameter T, which is the period of infectivity one can give a simple account for some of the differences in the observed contact networks for different diseases, such as smallpox, or AIDS. Our simplistic model also seems to shed some light on the shape of the degree distribution of the measured people-people contact network from the EPISIM data. We certainly do not claim that the simplistic graph integration model above is a good model for dynamic contact graphs. It only contains the essential ingredients for such processes to produce a qualitative agreement with some observations. We expect that further refinements and extensions to this picture, in particular deriving the link-probabilities in the dynamic proximity graph from more realistic contact dynamics should improve the agreement between models and data.

Guclu, Hasan; Toroczkai, Zoltán

2007-03-01

52

Multiplexed protein detection by proximity  

E-print Network

Multiplexed protein detection by proximity ligation for cancer biomarker validation Simon a proximity ligation­based multiplexed protein detection procedure in which several selected proteins can that for proteins. Proximity ligation has been developed in an attempt to bridge this gap and thereby improve

Cai, Long

53

Mechanosensory function of microvilli of the kidney proximal tubule  

PubMed Central

Normal variations in glomerular filtration induce proportional changes in proximal tubule Na+ reabsorption. This “glomerulotubular balance” derives from flow dependence of Na+ uptake across luminal cell membranes; however, the underlying physical mechanism is unknown. Our hypothesis is that flow-dependent reabsorption is an autoregulatory mechanism that is independent of neural and hormonal systems. It is signaled by the hydrodynamic torque (bending moment) on epithelial microvilli. Such signals need to be transmitted to the terminal web to modulate Na+-H+-exchange activity. To investigate this hypothesis, we examined Na+ transport and tubular diameter in response to different flow rates during the microperfusion of isolated S2 proximal tubules from mouse kidneys. The data were analyzed by using a mathematical model to estimate the microvillous torque as function of flow. In this model, increases in luminal diameter have the effect of blunting the impact of flow velocity on microvillous shear stress and, thus, microvillous torque. We found that variations in microvillous torque produce nearly identical fractional changes in Na+ reabsorption. Furthermore, the flow-dependent Na+ transport is increased by increasing luminal fluid viscosity, diminished in Na+-H+ exchanger isoform 3 knockout mice, and abolished by nontoxic disruption of the actin cytoskeleton. These data support our hypothesis that the “brush-border” microvilli serve a mechanosensory function in which fluid dynamic torque is transmitted to the actin cytoskeleton and modulates Na+ absorption in kidney proximal tubules. PMID:15319475

Du, Zhaopeng; Duan, Yi; Yan, QingShang; Weinstein, Alan M.; Weinbaum, Sheldon; Wang, Tong

2004-01-01

54

Some Properties of Fuzzy Soft Proximity Spaces  

PubMed Central

We study the fuzzy soft proximity spaces in Katsaras's sense. First, we show how a fuzzy soft topology is derived from a fuzzy soft proximity. Also, we define the notion of fuzzy soft ?-neighborhood in the fuzzy soft proximity space which offers an alternative approach to the study of fuzzy soft proximity spaces. Later, we obtain the initial fuzzy soft proximity determined by a family of fuzzy soft proximities. Finally, we investigate relationship between fuzzy soft proximities and proximities.

Demir, ?zzettin; Özbak?r, Oya Bedre

2015-01-01

55

Distributed Optoelectronic Proximity Sensor  

NASA Technical Reports Server (NTRS)

Optoelectronic proximity sensor comprises seven identical units functioning together to provide partially redundant data on spatial relationship between sensor and nearby diffusely reflecting surface. Provides data on distance, relative orientation, and curvature of surface. Sensor called "Hexeye" because its units exhibit hexagonal symmetry when viewed along optical axes and mounted together in hexagonal close packing. Because all six arrays of photodetectors in unit measure essentially identical distributions of light in operating mode, each provides redundant information averaged to increase accuracy or used to verify operation of others. Malfunctioning photodector identified, and output ignored or replaced by interpolated value. Developed for use in such robotic applications as noncontact probing or scanning of surfaces, localization and recognition of objects, and guiding "smart" robot hands in grasping objects.

Lee, Sukhan; Hahn, Hernsoo

1994-01-01

56

Analysis of standing droplets in rat proximal tubules  

PubMed Central

Volume, osmolality, and concentrations for Na, Cl, and raffinose have been measured as a function of time in standing droplets within rat intermediate and late proximal tubules. Standing droplet reabsorption proceeds without the development of a measurable osmotic difference across the epithelium. After 140 s of tubular exposure, droplet-to- plasma concentration differences are observed for raffinose, Na, and Cl with the observed Na concentration difference, usually referred to as limiting gradient, being approximately 9 mM. It is possible that a smaller or even no limiting difference would be attained with longer exposure times. Previous values measured for the limiting Na concentration in the rat proximal tubule were determined before the attainment of constant concentrations. Assuming that the Na concentration we measured is the limiting value, we estimate that active NaCl transport accounts for a very small fraction, less than 6%, of the volume reabsorption; using an alternative approach of fitting a theoretical model to our experimental data, active NaCl transport is again estimated to account for only 6% of the total reabsorbate. The previous interpretation that a limiting Na concentration gradient constitutes the most direct evidence for active Na transport may be in error; the gradient we measure can be modeled without incorporating active NaCl transport. PMID:7069399

1982-01-01

57

Derivative-Free Optimization Proximal Point Methods Derivative-Free Proximal Point Conclusion Derivative-Free Optimization via Proximal  

E-print Network

Derivative-Free Optimization Proximal Point Methods Derivative-Free Proximal Point Conclusion Derivative-Free Optimization via Proximal Point Methods Yves Lucet & Warren Hare July 24, 2013 1 / 26 #12;Derivative-Free Optimization Proximal Point Methods Derivative-Free Proximal Point Conclusion Outline 1

58

Alternating proximal regularized dictionary learning.  

PubMed

We present an algorithm for dictionary learning that is based on the alternating proximal algorithm studied by Attouch, Bolte, Redont, and Soubeyran (2010), coupled with a reliable and efficient dual algorithm for computation of the related proximity operators. This algorithm is suitable for a general dictionary learning model composed of a Bregman-type data fit term that accounts for the goodness of the representation and several convex penalization terms on the coefficients and atoms, explaining the prior knowledge at hand. As Attouch et al. recently proved, an alternating proximal scheme ensures better convergence properties than the simpler alternating minimization. We take care of the issue of inexactness in the computation of the involved proximity operators, giving a sound stopping criterion for the dual inner algorithm, which keeps under control the related errors, unavoidable for such a complex penalty terms, providing ultimately an overall effective procedure. Thanks to the generality of the proposed framework, we give an application in the context of genome-wide data understanding, revising the model proposed by Nowak, Hastie, Pollack, and Tibshirani (2011). The aim is to extract latent features (atoms) and perform segmentation on array-based comparative genomic hybridization (aCGH) data. We improve several important aspects that increase the quality and interpretability of the results. We show the effectiveness of the proposed model with two experiments on synthetic data, which highlight the enhancements over the original model. PMID:25248086

Salzo, Saverio; Masecchia, Salvatore; Verri, Alessandro; Barla, Annalisa

2014-12-01

59

Geographic Proximity and Enrollment Competition.  

ERIC Educational Resources Information Center

The use of a measure of geographic proximity to help explain enrollment competition among postsecondary institutions was investigated. The measure, the number of miles between institutions, was obtained by determining the longitude and latitude coordinates for about 99% of the schools in the Higher Education General Information System universe.…

Zammuto, Raymond F.

60

Radio Proximity-Fuze Development  

Microsoft Academic Search

The general principles governing the design of radio proximity fuzes are presented. The paper deals primarily with fuzes for smooth-bore projectiles, such as bombs, rockets, and mortars. Illustrations and descriptions of the various fuzes in this category which were developed during World War II are given. Within security regulations, there is a reasonably detailed discussion of the performance and constraction

C. Brunetti

1946-01-01

61

Proximity Sensors Make Robot Dexterous  

NASA Technical Reports Server (NTRS)

Control system enables robot hand to grasp objects of varied shapes. Key features of system: reflective proximity sensors furnishing data on position, orientation, and distance of object and software protocol controlling sequence of operations in approaching and grasping objects. Reflected-beam sensing concept applied to simple opposed-jaw industrial grippers as well as to dexterous robot hands.

Hess, Cliff; Li, Larry C. H.

1990-01-01

62

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 ...

63

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 of the sensor. 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.

McEwan, Thomas E. (Livermore, CA)

1998-01-01

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

Proximal Humerus Reconstructions for Tumors  

PubMed Central

The optimal method for reconstructing the proximal humerus in patients with tumors is controversial. To determine functional outcomes and complication rates after different types of reconstructions, we reviewed a consecutive series of 49 patients who underwent proximal humerus resection and osteoarticular allograft (17 patients), allograft-prosthetic composite (16), or endoprosthetic (16) reconstruction. Operative indications included primary malignancies (24 patients), metastatic disease (19), and benign aggressive disease (six). Implant revision was more common after osteoarticular reconstruction (five of 17) than after allograft-prosthetic composite (one of 16) or endoprosthetic (zero of 16) reconstructions. At a minimum followup of 24 months (median, 98 months; range, 24–214 months) in surviving patients, Musculoskeletal Tumor Society functional scores averaged 79% for the allograft-prosthetic composite, 71% for the osteoarticular allograft, and 69% for the endoprosthetic reconstruction cohorts. Shoulder instability was associated with abductor mechanism compromise and was more common after endoprosthetic reconstruction. Allograft fractures occurred in 53% of patients receiving osteoarticular allografts. We recommend allograft-prosthetic composite reconstruction for younger patients with primary tumors of bone and endoprosthetic reconstruction for older patients with metastatic disease. Because of the unacceptable complication rate, we do not recommend osteoarticular allograft reconstruction for routine use in the proximal humerus. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18820983

Adams, Sheila C.; Pitcher, J. David; Malinin, Theodore I.; Temple, H. Thomas

2008-01-01

66

Proximity and Innovation: From Statics to Dynamics  

E-print Network

Proximity and Innovation: From Statics to Dynamics PIERRE-ALEXANDRE BALLAND*, RON BOSCHMA* and KOEN remained essentially static. A dynamic extension of the proximity framework is proposed that accounts: in revised form January 2014) BALLAND P.-A., BOSCHMA R. and FRENKEN K. Proximity and innovation: from statics

Balland, Pierre-Alexandre

67

A Scalarization Proximal Point Method for Quasiconvex ...  

E-print Network

Program New Frontiers UFRJ/UFT. †Federal University of ... [6], proposed an interior proximal algorithm inspired by the logarithmic- quadratic proximal method for linearly constrained quasiconvex minimization problems. For that method ... point method to solve the quasiconvex multiobjective problem (1). The proximal point ...

2014-07-24

68

Investigation of proximity coupled antenna structures  

Microsoft Academic Search

Proximity coupled microstrip patch antennas (D.M. Pozar and B. Kaufman, Electron. Lett. vol. 23, no. 8, pp. 369-369, 1987) offer various advantages over conventional edge or probe fed patches. In this paper we investigate the standard proximity coupled printed antenna design and highlight the critical design parameters. We also present a stacked proximity coupled antenna, which achieves a broad bandwidth

W. S. T. Rowe; R. B. Waterhouse

2003-01-01

69

The HTV Proximity Communication System  

NASA Astrophysics Data System (ADS)

National Space Development Agency of Japan (NASDA) is developing the H-II Transfer Vehicle (HTV) as an unmanned logistic support vehicle for the International Space Station (ISS). The HTV, which is launched by the H-IIA rocket, transports both pressurized and un-pressurized cargoes to the ISS, reloads disposal items from the ISS and performs destructive reentry over ocean area. NASDA plans the first flight of HTV in 2005 for demonstration. The HTV will contribute the ISS assembly and logistic re-supply operations with international commonality. For unmanned vehicle operation, communication link is critical with commanding and control, especially in proximity region to the ISS. As for the HTV operation, NASDA is developing dedicated communication system installed on the Japanese Experiment Module (JEM) of the ISS, which is called the Proximity Communication System (PROX). The HTV receives commands and transmits telemetry data through the PROX in its proximity operation to the ISS. To achieve this, the PROX can communicate with the HTV on its nominal trajectory within 23km of the ISS. Especially within 3km of the ISS, the PROX has capability to perform omni-directional communication to the HTV. The PROX also has GPS receiver and send GPS data to the HTV to support the HTV navigation for relative GPS navigation used in "far" range (500m away from the ISS). In addition to the above fundamental functions, the PROX has a capability of range and range-rate measurement between the ISS and the HTV by the pseudo noise (PN) code epoch and the Doppler shift frequency. This provides a reference data independent of "main" navigation methods (rendezvous sensor navigation or GPS navigation) of the HTV. The PROX also assists the ISS crew with its commanding device, called the Hardware Command Panel (HCP), to issue time-dependent safety-related critical commands for HTV berthing/un-berthing operation. When a failure occurs somewhere on "communication path" from the PROX Base Band Processor (BBP) to the HTV Guidance and Control Computer (GCC) including data handling and communication equipments, the PROX detects it by monitoring interruption of the "heartbeat" signal and conducts automatic redundancy switching of all the equipments on that "communication path" including those of the HTV. This paper describes the PROX functions such as communication, data handling and GPS navigation and some unique functions for the HTV proximity operation to the ISS.

Harada, Motoyuki; Takahashi, Tetsuo; Tanaka, Tetsuo

2002-01-01

70

Automated rendezvous and proximity operations  

NASA Technical Reports Server (NTRS)

IR&D efforts in recent years have focused on effective means of performing automated rendezvous and proximity operations. The primary focus for application has been to the Space Shuttle Orbiter and potential derivations, such as the Reusable Cargo Vehicle (RCV), studied in FY 1990. All candidate vehicle mission scenarios have included approach to docking or berthing with the Space Station Freedom (SSF). Results to date indicate that application of appropriate guidance algorithms can reduce docking contact or relative offset conditions, resulting in potential simplification of capture systems.

Flecklin, Anton F., II

1991-01-01

71

Highly Sensitive Superconducting Quantum-Interference Proximity Transistor  

NASA Astrophysics Data System (ADS)

We report the design and implementation of a high-performance superconducting quantum-interference proximity transistor based on aluminum-copper technology. With the adoption of a thin and short copper nanowire, we demonstrate full phase-driven modulation of the proximity-induced minigap in the normal-metal density of states. Under optimal bias, we record unprecedentedly high flux-to-voltage (up to 3 mV/?0) and flux-to-current (exceeding 100 nA/?0) transfer function values at subkelvin temperatures, where ?0 is the flux quantum. The best magnetic-flux resolution (as low as 500n?0/?Hz at 240 mK being limited by the room-temperature preamplification stage) is reached under fixed current bias. These figures of merit combined with ultralow power dissipation and micrometer-size dimensions make this mesoscopic interferometer attractive for low-temperature applications such as the investigation of the magnetization of small spin populations.

Ronzani, Alberto; Altimiras, Carles; Giazotto, Francesco

2014-08-01

72

Proximal bodies in hypersonic flow  

NASA Astrophysics Data System (ADS)

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 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 of the primary diameter. The analytical results are compared with those from numerical simulations and reasonable agreement is observed if an appropriate normalization for the relative lateral displacement of the two bodies 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.

Laurence, Stuart J.; Deiterding, R.; Hornung, G.

73

Ash Aggregates in Proximal Settings  

NASA Astrophysics Data System (ADS)

Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within <1 km of the vent. The deposits within the A418 pipe, Diavik Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (<62 ?m). Secondly, the ash aggregates indicate the involvement of moisture coupled with the presence of dilute expanded eruption clouds. The structure and distribution of these deposits throughout the kimberlite conduit demand that aggregation and deposition operate entirely within the confines of the vent; this indicates that aggregation is a rapid process. Ash aggregates within glaciovolcanic sequences are also rarely documented. The early pyroclastic phase of the formation of Kima'Kho, a tuya in northern B.C., Canada produced a subaqueous pyroclastic cone which became emergent during the latter stages of formation. Armoured lapilli are pervasive within the emergent upper third of the sequence. No other types of ash aggregates have been observed. Petrographic and textural analysis of the armoured lapilli shows them to comprise a central 2-30 mm-sized, juvenile, vesiculated pyroclast, concentrically coated by mm-scale layers of 10-250 ?m sized ash particles. At Kima'Kho, the armoured lapilli are shown to be a direct indicator of fallout from a sustained plume attended by concomitant production of pyroclastic density currents. The size and internal structure of the armoured lapilli provide constraints on the nature of the initial explosive phase of eruption at Kima'Kho. Their proximity to the vent also indicates rapid aggregation within the eruption plume. Within both sequences rapid aggregation of ash particles occurred in proximity to the vent. However, the conditions were substantially different leading to the production of armoured lapilli (no accretionary lapilli) at Kima'Kho and diverse ash aggregates but no armoured lapilli at A418. Here we investigate vent-proximal ash aggregation and the specific conditions which lead to the formation of coated ash pellets and armoured lapilli.

Porritt, L. A.; Russell, K.

2012-12-01

74

Claudin-2–deficient mice are defective in the leaky and cation-selective paracellular permeability properties of renal proximal tubules  

PubMed Central

Claudin-2 is highly expressed in tight junctions of mouse renal proximal tubules, which possess a leaky epithelium whose unique permeability properties underlie their high rate of NaCl reabsorption. To investigate the role of claudin-2 in paracellular NaCl transport in this nephron segment, we generated knockout mice lacking claudin-2 (Cldn2?/?). The Cldn2?/? mice displayed normal appearance, activity, growth, and behavior. Light microscopy revealed no gross histological abnormalities in the Cldn2?/? kidney. Ultrathin section and freeze-fracture replica electron microscopy revealed that, similar to those of wild types, the proximal tubules of Cldn2?/? mice were characterized by poorly developed tight junctions with one or two continuous tight junction strands. In contrast, studies in isolated, perfused S2 segments of proximal tubules showed that net transepithelial reabsorption of Na+, Cl–, and water was significantly decreased in Cldn2?/? mice and that there was an increase in paracellular shunt resistance without affecting the apical or basolateral membrane resistances. Moreover, deletion of claudin-2 caused a loss of cation (Na+) selectivity and therefore relative anion (Cl–) selectivity in the proximal tubule paracellular pathway. With free access to water and food, fractional Na+ and Cl– excretions in Cldn2?/? mice were similar to those in wild types, but both were greater in Cldn2?/? mice after i.v. administration of 2% NaCl. We conclude that claudin-2 constitutes leaky and cation (Na+)–selective paracellular channels within tight junctions of mouse proximal tubules. PMID:20385797

Muto, Shigeaki; Hata, Masaki; Taniguchi, Junichi; Tsuruoka, Shuichi; Moriwaki, Kazumasa; Saitou, Mitinori; Furuse, Kyoko; Sasaki, Hiroyuki; Fujimura, Akio; Imai, Masashi; Kusano, Eiji; Tsukita, Shoichiro; Furuse, Mikio

2010-01-01

75

Recurrent dislocation of the proximal tibiofibular joint.  

PubMed

Recurrent dislocation of the proximal tibiofibular joint is a rare injury. This report presents a case of bilateral recurrent dislocations of the proximal tibiofibular joint in a jet skier that responded to physical therapy and activity modification. A review of the literature is provided, with attention to the mechanism of injury and other treatment options--including arthrodesis and resection of the proximal fibula. This diagnosis should be considered in jet skiers with lateral-sided knee pain. PMID:1749660

Halbrecht, J L; Jackson, D W

1991-11-01

76

Intracellular cystine loading causes proximal tubule respiratory dysfunction: effect of glycine.  

PubMed

The present study examined proximal tubular respiration in control proximal tubules and proximal tubules loaded with cystine using 2 mmol/L cystine dimethyl ester. Basal oxygen consumption was significantly less in cystine-loaded tubules (20.6 +/- 0.5 versus 12.1 +/- 0.6 nmol O2.min-1.mg protein-1, p < 0.001). In the presence of 10(-4) mol/L ouabain, an inhibitor of the NaK ATPase, oxygen consumption was 10.2 +/- 0.7 nmol O2.min-1.mg protein-1 in control tubules and 11.4 +/- 1.0 nmol O2.min-1.mg protein-1 in cystine-loaded tubules. Thus, proximal tubular intracellular cystine loading specifically inhibits oxygen metabolism directed toward transport. Compared with control proximal tubules, cystine-loaded proximal tubules also had a lower rate of O2 consumption when the cells were permeabilized to sodium with nystatin and when mitochondrial respiration was uncoupled. Glycine, an amino acid that is cytoprotective to hypoxic proximal tubule injury, ameliorated the respiratory dysfunction observed in cystine-loaded tubules. PMID:1337587

Sakarcan, A; Aricheta, R; Baum, M

1992-12-01

77

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

78

Proximity sensing with wavelet-generated video  

Microsoft Academic Search

In this paper we introduce wavelet video processing of proximity sensor signals. Proximity sensing is required for a wide range of military and commercial applications, including weapon fuzing, robotics, and automotive collision a voidance. While ou r proposed method temporarily increases s ignal dimension, it eventually performs data compression through the extraction of salient signal features. This data compression in

Steven E. Noel; Harold H. Szu

1998-01-01

79

Proximal Participation: A Pathway into Work  

ERIC Educational Resources Information Center

In a longitudinal case study of apprentices, the term proximal participation was coined to describe the entry process of young people, with unclear career destinations, into the trade of baking. This article unravels the significance of proximal participation in the decision-making processes of young people who enter a trade through initial…

Chan, Selena

2013-01-01

80

Context-Aware Group Services in Proximity-Based Mobile Social Networks  

E-print Network

Groups exist in mobile users' social interactions Groups can be used for apps based on informationContext-Aware Group Services in Proximity-Based Mobile Social Networks Na Yu and Dr. Qi Han (http contexts into contacts to generate user mobility profiles with PoI visits and contacts; - Construct

81

Range gated strip proximity sensor  

DOEpatents

A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

82

Range gated strip proximity sensor  

DOEpatents

A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

McEwan, T.E.

1996-12-03

83

Proximal bodies in hypersonic flow  

NASA Astrophysics Data System (ADS)

The problem of proximal bodies in hypersonic flow is encountered in several important situations, both natural and man-made. The present work seeks to investigate one aspect of this problem by exploring the forces experienced by a secondary body when some part of it is within the shocked region created by 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 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 then one-sixth the primary diameter. The analytical results are compared with numerical simulations carried out using the AMROC software and good agreement is obtained 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, again with good agreement. In order to model this situation experimentally, a new force-measurement technique for short-duration hypersonic facilities has been developed, and results from the validation experiments are included. Finally, the analytical methodology is used to model two physical situations. First, the entry of a binary asteroid system into the Earth's atmosphere is simulated. Second, a model for a fragmenting meteoroid in a planetary atmosphere is developed, and simulations are carried out to determine whether the secondary scatter patterns in the Sikhote-Alin crater field may be attributed to aerodynamic interactions between fragments rather than to secondary fragmentation. It is found that while aerodynamic interactions lead to increased secondary crater grouping, these groups do not exhibit the typically elliptical shape that we would expect secondary fragmentation to produce.

Laurence, Stuart J.

84

Proximal phalangeal osteotomies for hallux abductovalgus deformity.  

PubMed

The primary indication for an osteotomy of the hallux proximal phalanx to correct hallux abductovalgus (HAV) deformities is increased hallux interphalangeus. The typical osteotomy is the Akin osteotomy or a variation. The Akin is a medial closing wedge osteotomy in the proximal phalanx. An Akin-type osteotomy is usually used as an adjunctive procedure for HAV to correct deformity within the great toe. When first metatarsal procedures and soft tissue balancing are not sufficient for realigning the first metatarsophalangeal joint, an Akin can be useful. A hallux proximal phalanx osteotomy is not indicated as the primary correction for HAV deformities. PMID:24685188

Rettedal, David; Lowery, Nicholas J

2014-04-01

85

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

PubMed

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 beta-glucuronidase and is associated with proteolytic degradation and reduced surface NaPi-2a. The inhibitory effect of Klotho on NaPi-2a was blocked by beta-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. PMID:20466874

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

2010-09-01

86

Casimir forces beyond the proximity approximation  

E-print Network

The proximity force approximation (PFA) relates the interaction between closely spaced, smoothly curved objects to the force between parallel plates. Precision experiments on Casimir forces necessitate, and spur research ...

Bimonte, G.

87

A fast distributed proximal-gradient method  

E-print Network

We present a distributed proximal-gradient method for optimizing the average of convex functions, each of which is the private local objective of an agent in a network with time-varying topology. The local objectives have ...

Chen, Annie I.

88

Control of spacecraft in proximity orbits  

E-print Network

Formation flying of spacecraft and autonomous rendezvous and docking of spacecraft are two missions in which satellites operate in close proximity and their relative trajectories are critically important. Both classes of ...

Breger, Louis Scott, 1979-

2007-01-01

89

Opportunistic, collaborative and synchronized, proximal device ecology  

E-print Network

CoSync is an on-device software framework for coordinating proximal consumer electronic devices in order to create a synchronized, opportunistic and collaborative device ecology. The CoSync device ecology combines multiple ...

Toledano, Eyal

2013-01-01

90

Promoting proximal formative assessment with relational discourse  

NASA Astrophysics Data System (ADS)

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.

2012-02-01

91

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

92

Proximity operations considerations affecting spacecraft design  

NASA Technical Reports Server (NTRS)

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.

1991-01-01

93

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. PMID:20466874

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

94

Analysis on the characteristics of pulsed laser proximity fuze's echo  

Microsoft Academic Search

With the rapid development of semiconductor technology and laser technology, a kind of proximity fuze named pulsed laser proximity fuze has been applied. Compared with other fuzes, pulsed laser proximity fuze has high ranging precision and strong resistance to artificial active interference. It is an important development tendency of proximity fuze. The paper analyze the characteristic of target echo of

Kun Wang; Huimin Chen

2011-01-01

95

Osmotic Volume Flow in the Proximal Tubule of Necturus Kidney  

PubMed Central

Volume changes due to osmotic flow in the distal portion of proximal tubules of Necturi were measured by the split oil drop technique. In agreement with previous findings no volume flow was induced by NaCl concentrations close to 60 mM. The tubule wall was found to be permeable to plasma electrolytes, which have an apparent reflection coefficient of 0.69. The mean apparent hydraulic conductivity was 0.33 x 10-11 cm3/dyne sec, comparable with other epithelia. A number of lipid-insoluble nonelectrolytes of widely varying molecular size had apparent reflection coefficients of about 0.5. In view of the insensitivity to molecular size it seems likely that apparent reflection coefficients determined from tubular volume changes depend primarily on the porosity of the intercellular barrier closest to the lumen and give little information about the subsequent fate of the test substances. PMID:5651770

Bentzel, Carl J.; Davies, Martin; Scott, Walter N.; Zatzman, Marvin; Solomon, A. K.

1968-01-01

96

Vascularized proximal fibular epiphyseal transfer: two cases.  

PubMed

Vascularized proximal fibular epiphyseal transfer in children enables reconstruction of long-bone epiphyseal defect, while conserving axial growth potential. This technique was applied in two children for diaphyseal-epiphyseal reconstruction of the proximal humerus and distal radius respectively, using a graft vascularized only by the anterior tibial artery. There were no major complications during harvesting. Both cases showed transplant growth, of a mean 0.5cm/year. Joint function in the proximal humerus reconstruction was satisfactory, with functional range of motion. In the distal radius reconstruction, range of motion was almost zero; insufficient transplant growth induced radial club hand, requiring partial correction by progressive lengthening using an external fixator. In case of severe bone loss, fibular epiphyseal-diaphyseal graft vascularized only by the anterior tibial artery is a feasible attitude. PMID:23000036

Medrykowski, F; Barbary, S; Gibert, N; Lascombes, P; Dautel, G

2012-10-01

97

Proximity operations concept design study, task 6  

NASA Technical Reports Server (NTRS)

The feasibility of using optical technology to perform the mission of the proximity operations communications subsystem on Space Station Freedom was determined. Proximity operations mission requirements are determined and the relationship to the overall operational environment of the space station is defined. From this information, the design requirements of the communication subsystem are derived. Based on these requirements, a preliminary design is developed and the feasibility of implementation determined. To support the Orbital Maneuvering Vehicle and National Space Transportation System, the optical system development is straightforward. The requirements on extra-vehicular activity are such as to allow large fields of uncertainty, thus exacerbating the acquisition problem; however, an approach is given that could mitigate this problem. In general, it is found that such a system could indeed perform the proximity operations mission requirement, with some development required to support extra-vehicular activity.

Williams, A. N.

1990-01-01

98

Endoscopic repair of proximal hamstring avulsion.  

PubMed

Hamstring muscle injuries are common in athletes and mostly consist of sprains at the myotendinous junction, which often respond well to conservative treatment. Proximal hamstring avulsion injuries, though less common, can be severely debilitating. This injury is often seen in water skiers but has been described in many other sports and in middle-aged patients. Complete avulsions in young and active individuals do not respond well to conservative treatment and may require surgical repair. In contrast, many partial tears may be treated nonoperatively. However, when symptoms continue despite a trial of extensive therapy, surgery may be warranted. Traditional surgery for proximal hamstring repair is performed with the patient in the prone position with an incision made longitudinally or along the gluteal fold, followed by identification of the torn tendons and fixation to the ischial tuberosity. We describe a novel surgical technique for endoscopic repair of proximal hamstring avulsion injuries. PMID:23767008

Domb, Benjamin G; Linder, Dror; Sharp, Kinzie G; Sadik, Adam; Gerhardt, Michael B

2013-02-01

99

Endoscopic Repair of Proximal Hamstring Avulsion  

PubMed Central

Hamstring muscle injuries are common in athletes and mostly consist of sprains at the myotendinous junction, which often respond well to conservative treatment. Proximal hamstring avulsion injuries, though less common, can be severely debilitating. This injury is often seen in water skiers but has been described in many other sports and in middle-aged patients. Complete avulsions in young and active individuals do not respond well to conservative treatment and may require surgical repair. In contrast, many partial tears may be treated nonoperatively. However, when symptoms continue despite a trial of extensive therapy, surgery may be warranted. Traditional surgery for proximal hamstring repair is performed with the patient in the prone position with an incision made longitudinally or along the gluteal fold, followed by identification of the torn tendons and fixation to the ischial tuberosity. We describe a novel surgical technique for endoscopic repair of proximal hamstring avulsion injuries. PMID:23767008

Domb, Benjamin G.; Linder, Dror; Sharp, Kinzie G.; Sadik, Adam; Gerhardt, Michael B.

2013-01-01

100

Hallux proximal phalanx Akin-Scarf osteotomy.  

PubMed

Numerous hallux proximal phalanx osteotomies have been described, but the Akin-type varisation or adduction osteotomies are currently the most commonly used by foot and ankle surgeons. This article describes the hallux proximal phalanx Akin-Scarf osteotomy. This osteotomy combines the inherent stability of the Scarf-type osteotomy with the versatility of the Akin-type osteotomies to correct pathologic hallux abductus interphalangeus, hallux equinus, or an abnormal digital length pattern, and it is an invaluable tool during the global surgical approach used for hallux valgus repair. PMID:14729996

Roukis, Thomas S

2004-01-01

101

Effect of formate on volume reabsorption in the rabbit proximal tubule.  

PubMed

Studies on microvillus membrane from rabbit kidney cortex suggest that chloride absorption may occur by chloride/formate exchange with recycling of formic acid by nonionic diffusion. We tested whether this transport mechanism participates in active NaCl reabsorption in the rabbit proximal tubule. In proximal tubule S2 segments perfused with low HCO-3 solutions, the addition of formate (0.25-0.5 mM) to the lumen and the bath increased volume reabsorption (JV) by 60%; the transepithelial potential difference remained unchanged. The effect of formate on JV was completely reversible and was inhibited both by ouabain and by luminal 4,4'-diisothiocyanostilbene-2,2'-disulfonate. Formate (0.5 mM) failed to stimulate JV in early proximal convoluted tubules perfused with high HCO-3 solutions. As measured by miniature glass pH microelectrodes, this lack of formate effect on JV was related to a less extensive acidification of the tubule fluid when high HCO-3 solutions were used as perfusate. These data suggest that chloride/formate exchange with recycling of formic acid by nonionic diffusion represents a mechanism for active, electroneutral NaCl reabsorption in the proximal tubule. PMID:3793930

Schild, L; Giebisch, G; Karniski, L P; Aronson, P S

1987-01-01

102

Administration of atrial natriuretic factor inhibits sodium-coupled transport in proximal tubules.  

PubMed

The newly discovered peptides extracted from cardiac atria, atrial natriuretic factors (ANFs), when administered parenterally cause renal hemodynamic changes and natriuresis. The nephron sites and cellular mechanism accounting for profound increase in Na+ excretion in response to ANFs are not yet clarified. In the present study we investigated whether synthetic ANF peptide alters the reabsorption of Na+ and reabsorption of solutes cotransported with Na+ in the proximal tubules of rats. Synthetic ANF peptide consisting of 26 amino acids, 4 micrograms/kg body wt/h, or vehicle in controls, was infused to surgically thyroparathyroidectomized anesthetized rats. After determination of the fractional excretion (FE) of electrolytes (Na+, K+, Pi, Ca2+, Mg2+, HCO3), the kidneys were removed and luminal brush border membrane vesicles (BBMVs) were prepared from renal cortex. Solute transport was measured in BBMVs by rapid filtration techniques. Infusion of ANF peptide increased FENa, FEPi, and FEHCO3; but FECa, FEK, and FEMg were not changed. The increase in FENa was significantly correlated, on the one hand, with increase of FEPi (r = 0.9, n = 7; P less than 0.01) and with increase of FEHCO3 (r = 0.89, n = 7; P less than 0.01). On the other hand, FENa did not correlate with FEK, FECa, or with FEMg. The Na+ gradient-dependent uptake of Pi by BBMVs prepared from renal cortex of rats receiving ANF infusion was significantly (P less than 0.05) decreased (-25%), whereas the Na+ gradient-dependent uptake of L-[3H]proline and of D-[3H]glucose or the diffusional uptake of 22Na+ were not changed. ANF-elicited change in FEPi showed a close inverse correlation with decrease of Na+-dependent Pi uptake by BBMVs isolated from infused rats (r = 0.99, n = 7; P less than 0.001). Direct addition of ANF to BBMVs in vitro did not change the Na+ gradient-dependent Pi uptake. In rats infused with ANF, the rate of amiloride-sensitive Na+-H+ exchange across the brush border membrane (BBM) was significantly (P less than 0.05) decreased (-40%), whereas the diffusional 22Na+ uptake (0.5 min) and the equilibrium (120 min) uptake of 22Na+ were not changed. The inhibition of Na+-H+ exchange after ANF was likely due to alteration of the BBM antiporter itself, in that the H+ conductance of BBMVs was not increased. We conclude that synthetic ANF (a) decreases tubular Na+ reabsorption linked to reabsorption of HCO3 in proximal tubules, and (b) inhibits proximal tubular reabsorption of Pi coupled to Na+ reabsorption, independent of secretion and/or action of parathyroid hormone or calcitonin. These ANF effects are associated with inhibition of Na+-Pi synport and of Na+-H+ antiport in luminal BBMs. Our findings document that inhibition of Na+-coupled transport processes in proximal tubules is an integral part of the renal response to ANF. PMID:2989338

Hammond, T G; Yusufi, A N; Knox, F G; Dousa, T P

1985-06-01

103

Administration of atrial natriuretic factor inhibits sodium-coupled transport in proximal tubules.  

PubMed Central

The newly discovered peptides extracted from cardiac atria, atrial natriuretic factors (ANFs), when administered parenterally cause renal hemodynamic changes and natriuresis. The nephron sites and cellular mechanism accounting for profound increase in Na+ excretion in response to ANFs are not yet clarified. In the present study we investigated whether synthetic ANF peptide alters the reabsorption of Na+ and reabsorption of solutes cotransported with Na+ in the proximal tubules of rats. Synthetic ANF peptide consisting of 26 amino acids, 4 micrograms/kg body wt/h, or vehicle in controls, was infused to surgically thyroparathyroidectomized anesthetized rats. After determination of the fractional excretion (FE) of electrolytes (Na+, K+, Pi, Ca2+, Mg2+, HCO3), the kidneys were removed and luminal brush border membrane vesicles (BBMVs) were prepared from renal cortex. Solute transport was measured in BBMVs by rapid filtration techniques. Infusion of ANF peptide increased FENa, FEPi, and FEHCO3; but FECa, FEK, and FEMg were not changed. The increase in FENa was significantly correlated, on the one hand, with increase of FEPi (r = 0.9, n = 7; P less than 0.01) and with increase of FEHCO3 (r = 0.89, n = 7; P less than 0.01). On the other hand, FENa did not correlate with FEK, FECa, or with FEMg. The Na+ gradient-dependent uptake of Pi by BBMVs prepared from renal cortex of rats receiving ANF infusion was significantly (P less than 0.05) decreased (-25%), whereas the Na+ gradient-dependent uptake of L-[3H]proline and of D-[3H]glucose or the diffusional uptake of 22Na+ were not changed. ANF-elicited change in FEPi showed a close inverse correlation with decrease of Na+-dependent Pi uptake by BBMVs isolated from infused rats (r = 0.99, n = 7; P less than 0.001). Direct addition of ANF to BBMVs in vitro did not change the Na+ gradient-dependent Pi uptake. In rats infused with ANF, the rate of amiloride-sensitive Na+-H+ exchange across the brush border membrane (BBM) was significantly (P less than 0.05) decreased (-40%), whereas the diffusional 22Na+ uptake (0.5 min) and the equilibrium (120 min) uptake of 22Na+ were not changed. The inhibition of Na+-H+ exchange after ANF was likely due to alteration of the BBM antiporter itself, in that the H+ conductance of BBMVs was not increased. We conclude that synthetic ANF (a) decreases tubular Na+ reabsorption linked to reabsorption of HCO3 in proximal tubules, and (b) inhibits proximal tubular reabsorption of Pi coupled to Na+ reabsorption, independent of secretion and/or action of parathyroid hormone or calcitonin. These ANF effects are associated with inhibition of Na+-Pi synport and of Na+-H+ antiport in luminal BBMs. Our findings document that inhibition of Na+-coupled transport processes in proximal tubules is an integral part of the renal response to ANF. PMID:2989338

Hammond, T G; Yusufi, A N; Knox, F G; Dousa, T P

1985-01-01

104

Proximal humerus fractures in children and adolescents.  

PubMed

Proximal humerus fractures are rare in paediatric traumatology. Metaphyseal fractures account for about 70% of cases and epiphyseal separation for the remaining 30%. The development and anatomy of the proximal humerus explain the various fracture types, displacements, and potential complications; and also help in interpreting the radiographic findings, most notably in young children. Physicians should be alert to the possibility of an underlying lesion or pathological fracture requiring appropriate diagnostic investigations, and they should consider child abuse in very young paediatric patients. Although the management of proximal humerus fractures remains controversial, the extraordinary remodelling potential of the proximal humerus in skeletally immature patients often allows non-operative treatment without prior reduction. When the displacement exceeds the remodelling potential suggested by the extent of impaction, angulation, and patient age, retrograde elastic stable intramedullary nailing (ESIN) provides effective stabilisation. As a result, the thoraco-brachial abduction cast is less often used, although this method remains a valid option. Retrograde ESIN must be performed by a surgeon who is thoroughly conversant with the fundamental underlying principles. Direct percutaneous pinning is a fall-back option when the surgeon's experience with ESIN is insufficient. Finally, open reduction is very rarely required and should be reserved for severely displaced fractures after failure of closed reduction. When these indications are followed, long-term outcomes are usually excellent, with prompt resumption of previous activities and a low rate of residual abnormalities. PMID:24394917

Lefèvre, Y; Journeau, P; Angelliaume, A; Bouty, A; Dobremez, E

2014-02-01

105

Fiber optical ranging sensor for proximity fuse  

Microsoft Academic Search

A fiber optical ranging sensor used in laser proximity fuze is described in this paper. In the fuze, pulse laser diode (LD) is used as light source and trigger signal is generated by comparing the reflected light pulses with the reference pulses by a correlator after they were converted into electric signals by PIN photodiodes. Multi-mode fibers and integrated optical

Fang Du; Zeying Chi; Mingjun You; Wenjian Chen

1996-01-01

106

The origins of the proximity fuze  

Microsoft Academic Search

The poor quality of antiaircraft artillery in 1940 could be traced to the uncertainties in determining the range to the target and in setting a time fuze accordingly. The proximity fuze eliminated these problems by sensing the presence of the aircraft

L. Brown

1998-01-01

107

The Zone of Proximal "Teacher" Development  

ERIC Educational Resources Information Center

Toward the end of his short life, Lev Vygotsky found himself teaching teachers in a remote part of the USSR. Though his influence as a developmental psychologist is well-established, little is known about his approach to teacher development. This article applies the researcher's core concept, the zone of proximal development to teacher education.…

Warford, Mark K.

2011-01-01

108

Isosmotic volume reabsorption in rat proximal tubule  

Microsoft Academic Search

A theoretical model incorporating both active and passive forces has been developed for fluid reabsorption from split oil droplets in rat inter- mediate and late proximal tubule. Of necessity, simplifying assumptions have been introduced; we have assumed that the epithelium can be treated as a single membrane and that the membrane \\

R. R. Warner; C. LECHENE

1980-01-01

109

Proximity and collaboration: measuring workplace configuration  

Microsoft Academic Search

Purpose – The purpose of this paper is to describe how to measure workplace configuration, show its application in, and the results of, a field experiment aimed at improving collaborative knowledge work and identify and discuss larger problems involved with research on workplace configuration. Design\\/methodology\\/approach – The paper reviews recent thought on density, proximity and problems with evaluating configuration. It

M. Gordon Brown

2008-01-01

110

Autonomous proximity awareness of Bluetooth devices  

Microsoft Academic Search

This paper focuses on designing autonomous device discovery algorithms for Bluetooth networks. We first extend the conventional asymmetric Bluetooth link model to three point-to-point symmetric link models. Their performances are compared analytically. To achieve proximity awareness among a group of Bluetooth devices, three control information exchanging methods are also proposed. Combining with the three link models, this gives 9 possible

Changlei Liu; Kwan L. Yeung

2005-01-01

111

Efficient k-word proximity search  

Microsoft Academic Search

In this paper, we propose the ldquoaddedrdquo use of proximity search to a Web search query for narrowing down the set of documents returned as answers to a keyword based search query. This approach adds value to Web search query results by allowing users to better express what they are looking for. Most of the current search engines provide limited

Chirag Gupta; Gultekin Özsoyoglu; Z. Meral Özsoyoglu

2009-01-01

112

Traumatic proximal tibiofibular dislocation with neurovascular injury  

PubMed Central

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

2012-01-01

113

Proximal Ureteral Calculi: Shock Wave or Ureterolithotripsy?  

Microsoft Academic Search

Objective: To compare the success rates and efficiency of ureterolithotripsy (URL) and extracorporeal shock wave lithotripsy (SWL) for proximal ureteric stones. Casuistry and Methods: A prospective non-randomized study was performed between 1999 and 2004. Of a total of 235 patients, 121 underwent SWL and 114 had ureteroscopy with ultrasonic lithotripsy. There were no significant differences between the groups. The success

Renato N. Pedro

2008-01-01

114

Efficiently Matching Proximity Relationships in Spatial Databases  

E-print Network

of real applications, such as real-estate marketing, urban planning, weather fore- casting, medical image, weather pattern analysis, urban plan- ning, transportation management, etc. While processing of typicalEfficiently Matching Proximity Relationships in Spatial Databases Xuemin Lin1 , Xiaomei Zhou1

Lin, Xuemin

115

Secreted frizzled-related protein-4 reduces sodium–phosphate co-transporter abundance and activity in proximal tubule cells  

Microsoft Academic Search

The phosphatonin, secreted frizzled-related protein-4 (sFRP-4), induces phosphaturia and inhibits 25-hydroxyvitamin D 1?-hydroxylase activity normally induced in response to hypophosphatemia. To determine the mechanism by which sFRP-4 alters renal phosphate (Pi) transport, we examined the effect of sFRP-4 on renal brush border membrane (BBMV) Na+-dependent Pi uptake, and the abundance and localization of the major Na+–Pi-IIa co-transporter in proximal tubules

Theresa J. Berndt; Bernhard Bielesz; Theodore A. Craig; Peter J. Tebben; Desa Bacic; Carsten A. Wagner; Stephen O’Brien; Susan Schiavi; Jurg Biber; Heini Murer; Rajiv Kumar

2006-01-01

116

[Open transscaphoid perilunate dislocation with proximal displacement of the lunate and proximal scaphoid].  

PubMed

The authors report a case of dorsal transscaphoid perilunate dislocation which is noteworthy because there was significant anterior displacement of the lunate together with the proximal part of the scaphoid. The lunate was propelled in front of the radial epiphysis and the proximal part of the scaphoid ended up in front of the metaphyseal part of the radius. An emergency partial proximal row carpectomy was performed, preserving the distal part of the scaphoid. Good anatomic and functional result was observed at 6 years follow-up. PMID:19233703

Razafimahandry, H J C; Rakoto-Ratsimba, H N; Gille, O

2009-04-01

117

The influence of intracellular sodium activity on the transport of glucose in proximal tubule of frog kidney  

Microsoft Academic Search

Inhibition of basolateral Na+\\/K+ ATPase by ouabain eventually abolishes transport of glucose. The present study was performed to test, if this effect is due to a dissipation of the electrochemical gradient for sodium or due to a regulatory inhibition of sodium-coupled glucose entry across the luminal membrane at increasing intracellular sodium activity. To this end, proximal convoluted tubules of the

F. Lang; G. Messner; W. Wang; M. Paulmichl; H. Oberleithner; P. Deetjen

1984-01-01

118

Importance of Proximal Tubular Fluid Output in Regulating Long-Term Urinary Sodium Excretion in Health and Disease  

Microsoft Academic Search

Current perceptions of the role of proximal tubular fluid output (Vprox) in the regulation of Na+ and fluid balance are based largely on the results of micropuncture studies in rats that have focused on the response of Vprox to acute pharmacological, physiological, or physical interventions. Much less attention has been paid to the role of Vprox in maintaining homeostasis during

Klaus Thomsen; David G. Shirley

2002-01-01

119

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. PMID:24086563

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

2013-01-01

120

Proximity-induced topological state in graphene  

NASA Astrophysics Data System (ADS)

The appearance of topologically protected states at the surface of an ordinary insulator is a rare occurrence and to date only a handful of materials are known for having this property. An intriguing question concerns the possibility of forming topologically protected interfaces between different materials. Here we propose that a topological phase can be transferred to graphene by proximity with the three-dimensional topological insulator Bi2Se3. By using density functional and transport theory, we prove that, at the verge of the chemical bond formation, a hybrid state forms at the graphene/Bi2Se3 interface. The state has Dirac-cone-like dispersion at the ? point and a well defined helical spin texture, indicating its topologically protected nature. This demonstrates that proximity can transfer the topological phase from Bi2Se3 to graphene.

Popov, Igor; Mantega, Mauro; Narayan, Awadhesh; Sanvito, Stefano

2014-07-01

121

Goal-proximity decision-making.  

PubMed

Reinforcement learning (RL) models of decision-making cannot account for human decisions in the absence of prior reward or punishment. We propose a mechanism for choosing among available options based on goal-option association strengths, where association strengths between objects represent previously experienced object proximity. The proposed mechanism, Goal-Proximity Decision-making (GPD), is implemented within the ACT-R cognitive framework. GPD is found to be more efficient than RL in three maze-navigation simulations. GPD advantages over RL seem to grow as task difficulty is increased. An experiment is presented where participants are asked to make choices in the absence of prior reward. GPD captures human performance in this experiment better than RL. PMID:23551486

Veksler, Vladislav D; Gray, Wayne D; Schoelles, Michael J

2013-01-01

122

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. PMID:24052727

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

2012-01-01

123

Proximity and Investment: Evidence from Plant-Level Data  

E-print Network

Proximity to plants makes it easier for headquarters to monitor and acquire information about plants. In this article, I estimate the effects of headquarters’ proximity to plants on plant-level investment and productivity. ...

Giroud, Xavier

124

REACH : the local social favor exchange : a proximal messaging system  

E-print Network

We define proximal messaging as that category of information transaction that takes into account the physical, social and temporal proximity between the sender and recipient as it relates to the content of the message. We ...

Kizelshteyn, Boris G. (Boris Grigory)

2012-01-01

125

[Peptic ulcer recurrence after selective proximal vagotomy].  

PubMed

A study of the structure of recurrences of ulcer disease was made on the basis of long-term follow-up results in 257 patients with selective proximal vagotomies. Real (with the presence of an ulcer) and false (without ulcer) recurrences are distinguished. The clinical aspects of the course and diagnosis of real and false recurrences are described. The principles of prophylaxis and treatment of ulcer disease recurrences are outlined. PMID:2756674

Polous, Iu M; Shidlovski?, V A; Gorbunova, V I; Va?sberg, G R

1989-04-01

126

Ranging\\/tracking system for proximity operations  

Microsoft Academic Search

The hardware development and testing phase of a hand held radar for the ranging and tracking for Shuttle proximity operations are considered. The radar is to measure range to a 3 sigma accuracy of 1 m (3.28 ft) to a maximum range of 1850 m (6000 ft) and velocity to a 3 sigma accuracy of 0.03 m\\/s (0.1 ft\\/s). Size

P. Nilsen; S. Udalov

1982-01-01

127

Space robotic system for proximity operations  

NASA Technical Reports Server (NTRS)

Key to an efficient accomplishment of space station servicing operations is the development of a scenario where the presence of man in space is well integrated with the capability of teleoperated and automatic robot system outside the stations. Results focusing on mission requirements, trajectory sequences, propulsion subsystem features, and manipulative kit characteristics relevant to proximity servicing during a Man Tended Free Flyers Robotic Mission (MTFF-RM) are illustrated.

Magnani, P. G.; Colomba, M.

1989-01-01

128

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

129

Management of proximal humerus fractures in adults  

PubMed Central

The majority of proximal humerus fractures are low-energy osteoporotic injuries in the elderly and their incidence is increasing in the light of an ageing population. The diversity of fracture patterns encountered renders objective classification of prognostic value challenging. Non-operative management has been associated with good functional outcomes in stable, minimally displaced and certain types of displaced fractures. Absolute indications for surgery are infrequent and comprise compound, pathological, multi-fragmentary head-splitting fractures and fracture dislocations, as well as those associated with neurovascular injury. A constantly expanding range of reconstructive and replacement options however has been extending the indications for surgical management of complex proximal humerus fractures. As a result, management decisions are becoming increasingly complicated, in an attempt to provide the best possible treatment for each individual patient, that will successfully address their specific fracture configuration, comorbidities and functional expectations. Our aim was to review the management options available for the full range of proximal humerus fractures in adults, along with their specific advantages, disadvantages and outcomes. PMID:25405098

Vachtsevanos, Leonidas; Hayden, Lydia; Desai, Aravind S; Dramis, Asterios

2014-01-01

130

Management of proximal humerus fractures in adults.  

PubMed

The majority of proximal humerus fractures are low-energy osteoporotic injuries in the elderly and their incidence is increasing in the light of an ageing population. The diversity of fracture patterns encountered renders objective classification of prognostic value challenging. Non-operative management has been associated with good functional outcomes in stable, minimally displaced and certain types of displaced fractures. Absolute indications for surgery are infrequent and comprise compound, pathological, multi-fragmentary head-splitting fractures and fracture dislocations, as well as those associated with neurovascular injury. A constantly expanding range of reconstructive and replacement options however has been extending the indications for surgical management of complex proximal humerus fractures. As a result, management decisions are becoming increasingly complicated, in an attempt to provide the best possible treatment for each individual patient, that will successfully address their specific fracture configuration, comorbidities and functional expectations. Our aim was to review the management options available for the full range of proximal humerus fractures in adults, along with their specific advantages, disadvantages and outcomes. PMID:25405098

Vachtsevanos, Leonidas; Hayden, Lydia; Desai, Aravind S; Dramis, Asterios

2014-11-18

131

Lateral stability of the proximal interphalangeal joint.  

PubMed

Current diagnostic criteria and therapeutic guidelines for injuries to the collateral ligaments of the proximal interphalangeal (PIP) joint are imprecise and vague. Laxity determinations, failure analysis, radiographic stress testing, and microscopic dissections were performed on 112 PIP joints. The lateral collateral ligament (LCL) is the primary restraint to varus and valgus angulation of the PIP joint. Its palmar fibers are tight in joint extension and provide the first line of resistance to lateral angulation. Failure of the LCL almost always occurs proximally in a sequential fashion that begins with the palmar fibers and progresses to the more dorsal bundles. Proximal LCL disruption is followed by separation of the accessory collateral-LCL junction and finally by failure of the distal palmar plate. Midsubstance tears of the LCL are rare. If the lateral stress test shows more than 20 degrees of varus or valgus angulation, the LCL can be presumed to be completely disrupted. Angulation of less than 20 degrees is associated with a 53% chance of partial LCL failure and a 47% chance of complete disruption, but the proper position of the LCL will be maintained by the overlying connective tissues. A clinical investigation will be necessary to define the criteria for surgical intervention. PMID:3760491

Kiefhaber, T R; Stern, P J; Grood, E S

1986-09-01

132

Ferromagnet proximity effect in graphene bilayer  

NASA Astrophysics Data System (ADS)

A well-known effect of ferromagnet proximity in metallic thin film results in the giant magneto-resistance (GMR). In case of graphene monolayer, the effect of dielectric ferromagnet layer (DFL) proximity leads to formation of spin-dependent electron potential and electron spin rotation in effective exchange field. We theoretically consider the ferromagnet proximity effect in graphene bilayer (GBL), where bottom and top layers are affected by arbitrary oriented DFL. Our calculations show a drastic reconstruction of energy band structure with the top DFL magnetization rotation compared to the bottom one, which is assumed to be fixed by an antiferromagnetic substrate. If the top and bottom magnetic moments are parallel and equal, we obtain a simple spin split gapless band structure. As soon as symmetry between the top and the bottom GBL is broken by rotation of top DFL magnetization, the gap is opening; it reaches the magnitude of exchange field at antiparallel configuration. Calculated conductivity of GBL strongly depends on magnetic configuration demonstrating efficiency of the new mechanism of GMR.

Semenov, Yuriy; Zavada, John; Kim, Ki Wook

2008-03-01

133

Proximity sensing with wavelet generated video Steven E. Noel  

E-print Network

Proximity sensing with wavelet generated video Steven E. Noel The Center for Advanced Computer wavelet video processing of proximity sensor signals. Proximity sensing is required for a wide range of military and commercial applications, including weapon fuzing, robotics, and automotive collision avoidance

Noel, Steven

134

Triplet Supercurrents in Half Metals and Unconventional Proximity Effects  

E-print Network

-range Proximity effect and the effect of disorder in the half metal. #12;Odd frequency components #12;Leading is the decay length of the triplet components into the superconductor. #12;Proximity components in Half metalTriplet Supercurrents in Half Metals and Unconventional Proximity Effects Matthias Eschrig

Fominov, Yakov

135

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

136

Inferring Mobile Trajectories using a Network of Binary Proximity Sensors  

E-print Network

Inferring Mobile Trajectories using a Network of Binary Proximity Sensors Eunjoon Cho, Kevin Wong movement. In our work, we show that we can use a network of binary proximity sensors to detect paths-world office building. I. INTRODUCTION A network of binary proximity sensors has been shown to successfully

Gnawali, Omprakash

137

Computer Vision Based Navigation for Spacecraft Proximity Operations  

E-print Network

Computer Vision Based Navigation for Spacecraft Proximity Operations Brent Edward Tweddle, David W. Miller February 2010 SSL # 1-10 #12;#12;Computer Vision Based Navigation for Spacecraft Proximity of Technology. #12;2 #12;Computer Vision Based Navigation for Spacecraft Proximity Operations by Brent Edward

138

Efficient Text Classification by Weighted Proximal SVM* Dong Zhuang1  

E-print Network

Efficient Text Classification by Weighted Proximal SVM* Dong Zhuang1 , Benyu Zhang2 , Qiang Yang3 and fast training speed. Our method is based on a novel extension of the proximal SVM mode [3]. Previous studies on proximal SVM have focused on classification for low dimensional data and did not consider

Yang, Qiang

139

The mechanism of bicarbonate reabsorption in the proximal and distal tubules of the kidney. 1965.  

PubMed

The mechanism of HCO3- reabsorption in proximal and distal tubules was examined in rats undergoing NaHCO3 diuresis. The steady-state intratubular pH was measured with pH-sensitive glass microelectrodes and compared with the equilibrium pH calculated from the HCO3- concentration of the tubular fluid (measured with quinhydrone electrodes) and plasma Pco2. In the proximal tubule the intratubular pH and the equilibrium pH were identical, indicating no accumulation of excess H2CO3. After inhibition of carbonic anhydrase, however, intratubular pH was significantly lower (0.85 pH U) than the equilibrium pH. It was concluded that HCO3- reabsorption in the proximal tubule was mediated by H+ secretion, but that carbonic anhydrase located in the luminal membrane of the cell prevented H2CO3 from accumulating in the tubular fluid. In the distal tubule the intratubular pH was 0.85 U lower than the equilibrium pH. This difference could be obliterated by an intravenous injection of carbonic anhydrase. It was concluded that HCO3- reabsorption in this segment was also accomplished by H+ secretion. The accumulation of excess H2CO3 in the tubular fluid indicated that, in contrast to the proximal tubule, carbonic anhydrase was not located in the luminal membrane of distal tubular cells. PMID:9621300

Rector, F C; Carter, N W; Seldin, D W

1998-06-01

140

Revision of the Deficient Proximal Femur With a Proximal Femoral Allograft  

PubMed Central

Substantial bone loss is frequently encountered with revision hip arthroplasty. A proximal femoral allograft may be used to reconstitute bone stock in the multiply revised femur with segmental bone loss of greater than 5 cm. We retrospectively reviewed 92 patients (93 hips) who underwent such proximal femoral allografts. The average age at the surgery was 61 years. The average number of previous revision procedures was 2.5. Six patients were lost to followup. Thirty-four of 36 deceased patients had the original proximal femoral allograft at the time of death. The minimum followup for the 50 remaining patients was 15 years (average, 16.2 years; range, 15–22 years). Analysis included survivorship and radiographic assessment. Of the 50 patients reviewed, two had a failed reconstruction due to infection, six for aseptic loosening, three for nonunion, and four for dislocation. Revision of the proximal femoral allograft for all reasons excluding the acetabulum was performed in seven patients. At last followup, 42 patients (84%) had a well-functioning construct. Proximal femoral allograft for revision hip arthroplasty in femoral segmental bone loss is a durable alternative in most patients for a complex problem. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18972178

Safir, Oleg; Kellett, Catherine F.; Flint, Michael; Backstein, David

2008-01-01

141

Proximal femoral nail antirotation (PFNA) for treatment of osteoporotic proximal femoral fractures  

Microsoft Academic Search

Background  Unstable trochanteric fractures have been an enigma for the orthopedic surgeon in the community because of unpredictable results.\\u000a Cephalic intramedullary nails with proximal antirotation device are the treatment of choice for such patients.\\u000a \\u000a \\u000a \\u000a \\u000a Purpose  To report outcomes of 36 consecutive patients treated with a proximal femoral nail (PFNA) for osteoporotic trochanteric femoral\\u000a fractures.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The patients included 20 men and 16 women,

A. Raviraj; Ashish Anand; Murali Chakravarthy; Sanjay Pai

142

Fiber optical ranging sensor for proximity fuse  

NASA Astrophysics Data System (ADS)

A fiber optical ranging sensor used in laser proximity fuze is described in this paper. In the fuze, pulse laser diode (LD) is used as light source and trigger signal is generated by comparing the reflected light pulses with the reference pulses by a correlator after they were converted into electric signals by PIN photodiodes. Multi-mode fibers and integrated optical devices are used in the system so that the structure can be more compact. Optical fiber delay line is used to offer precise delay time for reference channel.

Du, Fang; Chi, Zeying; You, Mingjun; Chen, Wenjian

1996-09-01

143

Proximity-induced superconductivity in DNA.  

PubMed

Conductivity measurements on double-stranded DNA molecules deposited by a combing process across a submicron slit between rhenium/carbon metallic contacts reveal conduction to be ohmic between room temperature and 1 kelvin. The resistance per molecule is less than 100 kilohm and varies weakly with temperature. Below the superconducting transition temperature (1 kelvin) of the contacts, proximity-induced superconductivity is observed. These results imply that DNA molecules can be conducting down to millikelvin temperature and that phase coherence is maintained over several hundred nanometers. PMID:11209072

Kasumov, A Y; Kociak, M; Guéron, S; Reulet, B; Volkov, V T; Klinov, D V; Bouchiat, H

2001-01-12

144

Metastatic disease of the proximal femur.  

PubMed

Since January 1999, ten patients had undergone surgical treatment for metastatic bony lesions of proximal femur at this centre. Seven of these patients were treated for complete pathological fractures, one for impending fracture and one for revision of internal fixation and loosening of hemiarthroplasty. Primary malignancies were located in breast in four cases, prostate in three and one in lung, thyroid and neurofibrosarcoma. Two patients had died within six months after surgery, four after 1 year while the remaining four were still alive. The mean duration of survival was eleven months. Nine patients had been ambulating pain free and there were no failure of reconstruction. PMID:14556337

Faisham, W I; Zulmi, W; Biswal, B M

2003-03-01

145

Obesity and Supermarket Access: Proximity or Price?  

PubMed Central

Objectives. We examined whether physical proximity to supermarkets or supermarket price was more strongly associated with obesity risk. Methods. The Seattle Obesity Study (SOS) collected and geocoded data on home addresses and food shopping destinations for a representative sample of adult residents of King County, Washington. Supermarkets were stratified into 3 price levels based on average cost of the market basket. Sociodemographic and health data were obtained from a telephone survey. Modified Poisson regression was used to test the associations between obesity and supermarket variables. Results. Only 1 in 7 respondents reported shopping at the nearest supermarket. The risk of obesity was not associated with street network distances between home and the nearest supermarket or the supermarket that SOS participants reported as their primary food source. The type of supermarket, by price, was found to be inversely and significantly associated with obesity rates, even after adjusting for individual-level sociodemographic and lifestyle variables, and proximity measures (adjusted relative risk?=?0.34; 95% confidence interval?=?0.19, 0.63) Conclusions. Improving physical access to supermarkets may be one strategy to deal with the obesity epidemic; improving economic access to healthy foods is another. PMID:22698052

Aggarwal, Anju; Hurvitz, Philip M.; Monsivais, Pablo; Moudon, Anne V

2012-01-01

146

Intraosseous neurilemmoma of the proximal ulna  

PubMed Central

INTRODUCTION Neurilemmoma is a benign nerve sheath neoplasm commonly located in the soft tissue. Intraosseous neurilemmoma is rare, constituting less than 1% of primary bone tumors. PRESENTATION OF CASE A 21 year-old woman was presented with left elbow pain of 1-month duration. Plain radiographs showed a well-defined, lytic and expansile lesion of the proximal ulna. Computed tomography revealed cortical destruction and soft tissue extension. Because the tissue of origin for the tumor was uncertain, an open biopsy was performed. The specimens demonstrated a benign spindle cell tumor suggestive of a neurilemmoma, similar to a soft tissue neurilemmoma. The diagnosis of intraosseous neurilemmoma was established. Marginal excision of the soft tissue component and curettage of the lesion in the bone were performed. After 3.5 years of follow up, there is no clinical or radiographic finding to suggest any recurrence. DISCUSSION The major site of intraosseous neurilemmoma is the mandible. Occurrence in the long bone is particularly rare. Only two cases of intraosseous neurilemmoma involving the bones around the elbow have been reported to our knowledge; these cases arose in the distal humerus. We describe the first case of intraosseous neurilemmoma of the proximal ulna of the left elbow. The recommended treatment is conservative resection and bone grafting, as malignant change is extremely rare. CONCLUSION Although very rare, intraosseous neurilemmoma should be taken under consideration in the differential diagnosis of painful, radiographically benign-appearing osseous tumor around the elbow. PMID:25460435

Kito, Munehisa; Yoshimura, Yasuo; Isobe, Ken’ichi; Aoki, Kaoru; Momose, Takashige; Kato, Hiroyuki

2014-01-01

147

Demonstration of automated proximity and docking technology  

NASA Technical Reports Server (NTRS)

Automated spacecraft docking operations are being performed using a full scale motion based simulator and an optical sensor. This presentation will discuss the work in progress at TRW and MSFC facilities to study the problem of automated proximity and docking operations. The docking sensor used in the MSFC Optical Sensor and simulation runs are performed using the MSFC Flat Floor Facility. The control algorithms and six degrees of freedom (6DOF) simulation software were developed at TRW and integrated into the MSFC facility. Key issues being studied are the quantification of docking sensor requirements and operational constraints necessary to perform automated docking maneuvers, control algorithms capable of performing automated docking in the presence of sensitive and noisy sensor data, and sensor technologies for automated proximity and docking operations. As part of this study the MSFC sensor characteristics were analyzed and modeled so that off line simulation runs can be performed for control algorithm testing. Our goal is to develop and demonstrate full 6DOF docking capabilities with actual sensors on the MSFC motion based simulator. We present findings from actual docking simulation runs which show sensor and control loop performance as well as problem areas which require close attention. The evolution of various control algorithms using both phase plane and Clohessy-Wiltshire techniques are discussed. In addition, 6DOF target acquisition and control strategies are described.

Anderson, Robert L.; Tsugawa, Roy K.; Bryan, Thomas C.

1991-01-01

148

Proximal tibial osteotomy 1970-1995.  

PubMed Central

Proximal tibial osteotomy (PTO) as a surgical treatment for selected cases of unicompartmental knee joint arthritis has been performed by the author since 1970. The results of the first 113 cases were reported in October, 1978, at the Iowa Orthopaedic Society meeting. The study was continued through 1995 to include a total of 279 osteotomies in 230 patients. Each operation was performed by the author using the surgical technique as described by Coventry. Postoperative rehabilitation and follow-up remained constant throughout the 25 year period. A detailed retrospective review of all clinical records was undertaken to determine the long term results of PTO, using revision to total knee replacement or death as end points. Eighty-three patients died and 19 were lost to follow-up. A questionnaire regarding pain, function, and the necessity of further surgery was sent to the remainder. Each patient was contacted and invited back for a clinical evaluation and radiographs. At an average 13 year follow-up, 116 patients (42%) had no symptoms and were considered a good result. This long-term review revealed that, with strict adherence to the surgical principles of obtaining and maintaining proper alignment, proximal tibial osteotomy for unicompartmental arthritis can result in good function and symptomatic relief for an average of ten to 14 years. Images Figure 1 Figure 2A Figure 2B Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 11 Figure 12 Figure 13 PMID:9807708

Fisher, D. E.

1998-01-01

149

Protein structure alignment beyond spatial proximity  

PubMed Central

Protein structure alignment is a fundamental problem in computational structure biology. Many programs have been developed for automatic protein structure alignment, but most of them align two protein structures purely based upon geometric similarity without considering evolutionary and functional relationship. As such, these programs may generate structure alignments which are not very biologically meaningful from the evolutionary perspective. This paper presents a novel method DeepAlign for automatic pairwise protein structure alignment. DeepAlign aligns two protein structures using not only spatial proximity of equivalent residues (after rigid-body superposition), but also evolutionary relationship and hydrogen-bonding similarity. Experimental results show that DeepAlign can generate structure alignments much more consistent with manually-curated alignments than other automatic tools especially when proteins under consideration are remote homologs. These results imply that in addition to geometric similarity, evolutionary information and hydrogen-bonding similarity are essential to aligning two protein structures. PMID:23486213

Wang, Sheng; Ma, Jianzhu; Peng, Jian; Xu, Jinbo

2013-01-01

150

Intravenous immunoglobulin therapy in proximal diabetic neuropathy  

PubMed Central

A 57-year-old man with type 2 diabetes mellitus for 10 years showed progressive loss of muscle strength in both legs, pain and muscle atrophy in the femoral region and significant weight loss. On admission, he could not stand alone and used a wheelchair. He also complained of severe pain in the lower extremities. He was diagnosed with proximal diabetic neuropathy (PDN) by characteristic clinical and electrophysiological features. Intravenous immunoglobulin therapy (IVIg 0.4 g/kg×5 days) markedly reduced the severe pain and muscle weakness in the legs. Eventually, pain assessed by the Visual Analogue Scale was relieved by 80% and muscle strength was also well recovered, thereby enabling the patient to walk with a cane. The present case suggests that IVIg therapy may be effective for the relief of pain in PDN. PMID:21686696

Kawagashira, Yuichi; Watanabe, Hirohisa; Oki, Yumiko; Iijima, Masahiro; Koike, Haruki; Hattori, Naoki; Katsuno, Masahisa; Tanaka, Fumiaki; Sobue, Gen

2009-01-01

151

Parallel Proximity Detection for Computer Simulations  

NASA Technical Reports Server (NTRS)

The present invention discloses a system for performing proximity detection in computer simulations on parallel processing architectures utilizing a distribution list which includes movers and sensor coverages which check in and out of grids. Each mover maintains a list of sensors that detect the mover's motion as the mover and sensor coverages check in and out of the grids. Fuzzy grids are included by fuzzy resolution parameters to allow movers and sensor coverages to check in and out of grids without computing exact grid crossings. The movers check in and out of grids while moving sensors periodically inform the grids of their coverage. In addition, a lookahead function is also included for providing a generalized capability without making any limiting assumptions about the particular application to which it is applied. The lookahead function is initiated so that risk-free synchronization strategies never roll back grid events. The lookahead function adds fixed delays as events are scheduled for objects on other nodes.

Steinman, Jeffrey S. (Inventor); Wieland, Frederick P. (Inventor)

1998-01-01

152

Parallel Proximity Detection for Computer Simulation  

NASA Technical Reports Server (NTRS)

The present invention discloses a system for performing proximity detection in computer simulations on parallel processing architectures utilizing a distribution list which includes movers and sensor coverages which check in and out of grids. Each mover maintains a list of sensors that detect the mover's motion as the mover and sensor coverages check in and out of the grids. Fuzzy grids are includes by fuzzy resolution parameters to allow movers and sensor coverages to check in and out of grids without computing exact grid crossings. The movers check in and out of grids while moving sensors periodically inform the grids of their coverage. In addition, a lookahead function is also included for providing a generalized capability without making any limiting assumptions about the particular application to which it is applied. The lookahead function is initiated so that risk-free synchronization strategies never roll back grid events. The lookahead function adds fixed delays as events are scheduled for objects on other nodes.

Steinman, Jeffrey S. (Inventor); Wieland, Frederick P. (Inventor)

1997-01-01

153

Ecology: the proximate cause of frog declines?  

PubMed

Pounds et al. argue that global warming contributes to amphibian declines by encouraging outbreaks of the chytrid fungus Batrachochytrium dendrobatidis. Although our findings agree with the climate-linked epidemic hypothesis, this pathogen is probably not the only proximate factor in such cases: in the Trasimeno Lake area of Umbria in central Italy, for example, the water frog Rana lessonae first declined in the late 1990s, yet chytridiomycosis was not observed until 2003 (refs 5, 6). Here we show that the chytrid was common there throughout 1999-2002, in a previously unknown form that did not cause disease. We therefore think that the focus by Pounds et al. on a single pathogen is hard to justify because the host-parasite ecology is at present so poorly understood. PMID:17538572

Di Rosa, Ines; Simoncelli, Francesca; Fagotti, Anna; Pascolini, Rita

2007-05-31

154

[Ophthalmologists in the proximity of Adolf Hitler].  

PubMed

Adolf Hitler met or at least knew about 5 ophthalmologists. The chair of ophthalmology in Berlin, Walther Löhlein, personally examined Hitler's eyes at least two times. The chair of ophthalmology in Breslau, Walter Dieter, developed "air raid protection spectacles" with the aid of high representatives of the NS-system and probably Adolf Hitler himself. Heinrich Wilhelm Kranz became rector of the universities of Giessen and Frankfurt/Main. He was known as a very strict advocate of the NS-race hygiene. Werner Zabel made plans for Hitler's diet and tried to interfere with Hitler's medical treatment. Finally, Hellmuth Unger was an influential representative of the medical press and a famous writer. Three of his novels with medical topics were made into a film which Hitler probably saw. Hitler had, so to say, a small "ophthalmological proximity" which, however, did not play a significant role for himself or the NS-state. PMID:22664943

Rohrbach, J M

2012-10-01

155

The interior proximal extragradient method for solving equilibrium problems  

Microsoft Academic Search

In this article we present a new and efficient method for solving equilibrium problems on polyhedra. The method is based on\\u000a an interior-quadratic proximal term which replaces the usual quadratic proximal term. This leads to an interior proximal type\\u000a algorithm. Each iteration consists in a prediction step followed by a correction step as in the extragradient method. In a\\u000a first

Thi Thu Van Nguyen; Jean-jacques Strodiot; Van Hien Nguyen

2009-01-01

156

Proximity to mining industry and cancer mortality.  

PubMed

Mining installations are releasing toxic substances into the environment which could pose a health problem to populations in their vicinity. We sought to investigate whether there might be excess cancer-related mortality in populations residing in towns lying in the vicinity of Spanish mining industries governed by the Integrated Pollution Prevention and Control Directive, and the European Pollutant Release and Transfer Register Regulation, according to the type of extraction method used. An ecologic study was designed to examine municipal mortality due to 32 types of cancer, across the period 1997 through 2006. Population exposure to pollution was estimated on the basis of distance from town of residence to pollution source. Poisson regression models, using the Bayesian conditional autoregressive model proposed by Besag, York and Molliè and Integrated Nested Laplace Approximations for Bayesian inference, were used: to analyze risk of dying from cancer in a 5-kilometer zone around mining installations; effect of type of industrial activity; and to conduct individual analyses within a 50-kilometer radius of each installation. Excess mortality (relative risk, 95% credible interval) of colorectal cancer (1.097, 1.041-1.157), lung cancer (1.066, 1.009-1.126) specifically related with proximity to opencast coal mining, bladder cancer (1.106, 1.016-1.203) and leukemia (1.093, 1.003-1.191) related with other opencast mining installations, was detected among the overall population in the vicinity of mining installations. Other tumors also associated in the stratified analysis by type of mine, were: thyroid, gallbladder and liver cancers (underground coal installations); brain cancer (opencast coal mining); stomach cancer (coal and other opencast mining installations); and myeloma (underground mining installations). The results suggested an association between risk of dying due to digestive, respiratory, hematologic and thyroid cancers and proximity to Spanish mining industries. These associations were dependent on the type of mine. PMID:22846765

Fernández-Navarro, Pablo; García-Pérez, Javier; Ramis, Rebeca; Boldo, Elena; López-Abente, Gonzalo

2012-10-01

157

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

158

Nailing proximal femur fractures: how to choose starting point and proximal screw configuration.  

PubMed

Fractures of the proximal femur can be a challenging treatment dilemma for the orthopaedic surgeon. Complex mechanical forces and anatomic variables in this region combine to make treatment of these injuries difficult and can often result in serious complications. The decision to treat this fracture with an intramedullary device requires the surgeon evaluate many variables in the context of the specific fracture pattern. These include the choice of implant, starting portal location, and positioning of the patient. Assessment of the fracture pattern and its 3 dimensional orientation is usually accomplished with the aid of advanced imaging. The patient's physiological status, body habitus and bone quality must also be incorporated into the treatment algorithm. We review these issues and how they factor into the decision making process in order to develop a successful operative plan for these injuries. We will review the starting portal selection, reduction and insertion techniques and examine options for proximal locking screw configurations. PMID:25756823

Nicolaou, Daemeon; Watson, J Tracy

2015-04-01

159

Proximity Operations and Docking Sensor Development  

NASA Technical Reports Server (NTRS)

The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been under development for the last three years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in spot mode out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. 12 Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor was updated to allow it to support the CEV and COTS programs. The flight proven AR&D sensor has been redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities include greater sensor range, auto ranging capability, and real-time video output. This paper presents some sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the brassboard and proto-type NGAVGS units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.

Howard, Richard T.; Bryan, Thomas C.; Brewster, Linda L.; Lee, James E.

2009-01-01

160

Proximal tubular lactate transport in rat kidney: A micropuncture study  

Microsoft Academic Search

Proximal tubular lactate transport in rat kidney: A micropuncture study. Micropuncture studies of renal lactate behavior in the rat showed free filtration across the glomerular membrane. Under free-flow conditions, 95% of the filtered load was reabsorbed by the proximal tubule, thus generating a transtubular concentration gradient. In the absence of volume changes, an intratubular steady-state concentration of lactate was established

Bernhard Höhmann; Peter P Frohnert; Rolf Kinne; Karl Baumann; F Papavassiliou; M Wagner

1974-01-01

161

Linking people through physical proximity in a conference  

Microsoft Academic Search

Past research has studied offline proximity such as co-location and online social connections such as friendship individually. People form social relationships based on certain characteristics they possess, called social selection. When people change their social behavior due to interaction with others, social influence is at work. However, few researchers have examined the relationship that exists between offline proximity and online

Alvin Chin; Bin Xu; Hao Wang; Xia Wang

2012-01-01

162

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

163

Group Proximity Measure for Recommending Groups in Online Social Networks  

Microsoft Academic Search

There are currently, thousands of online social networks (OSN) available, each of which hosts millions of users. Users make new friendship links, join groups on diverse topics, share opinions and thus help in building a big knowledge repository. In this paper we study the problem of defining proximity measure between groups (communities) of OSN. Understanding the proximity among the groups

Barna Saha; Lise Getoor

164

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

165

Explicit trade-off rules in proximate adaptive agents  

Microsoft Academic Search

Organisms in nature are both proximate (operating by rules of thumb) and adapted (the rules influenced by natural selection). We introduce new methods that can be used to study in silico versions of organisms behaving according to proximate adapted rules. Our approach goes beyond neural networks and offers an alternative to optimization methods. It is based on the idea that

Jarl Giske; Marc Mangel; Per Jakobsen; Geir Huse; Chris Wilcox; Espen Strand

2003-01-01

166

Mechanisms of fluid absorption during proximal tubule development  

Microsoft Academic Search

Mechanisms of fluid absorption during proximal tubule development. Passive permeation characteristics and paracellular pathway ultrastructure were studied in vitro by perfusion of rabbit isolated proximal convoluted tubules during postnatal ontogenesis. The influence upon net volume flow (Jv) of transepithelial hydrostatic and protein osmotic pressure was significantly higher during early postnatal maturation than in the mature tubule. Hydraulic hydrostatic conductance (×10?3

Michael Horster; Lars Larsson

1976-01-01

167

The Spatial Evolution of Innovation Networks: A Proximity Perspective  

Microsoft Academic Search

We propose an evolutionary perspective on the geography of network formation that is grounded in a dynamic proximity framework. In doing so, we root the proximity concept in an evolutionary approach to the geography of innovation networks. We discuss three topics. The first topic focuses on explaining the structure of networks. The second topic concentrates on explaining the effects of

Ron Boschma; Koen Frenken

2009-01-01

168

Scalable proximity estimation and link prediction in online social networks  

Microsoft Academic Search

Proximity measures quantify the closeness or similarity between nodes in a social network and form the basis of a range of appli- cations in social sciences, business, information technology, com- puter networks, and cyber security. It is challenging to estimate proximity measures in online social networks due to their massive scale (with millions of users) and dynamic nature (with hundreds

Han Hee Song; Tae Won Cho; Vacha Dave; Yin Zhang; Lili Qiu

2009-01-01

169

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

170

Generalized ligament laxity associated with isolated proximal tibiofibular joint dislocation  

Microsoft Academic Search

Proximal tibiofibular dislocations are a rare orthopaedic injury. It is one that is easily missed if one does not have high clinical suspicion for such an injury. This report discusses two cases of proximal tibiofibular dislocations that presented to the emergency department. In both cases, the patients fulfilled the criteria for having generalized ligamentous laxity—including passive apposition of thumb to

Royce Ekkawit Paschkewitz; Buddhika Balalla; Peter John Papantoniou; Siew-Piau Tan

2006-01-01

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

Trabecular Bone Contributes to Strength of the Proximal Femur Under  

E-print Network

to fracture the whole proximal femur in mediolateral impacts (from 0.37 joule in controls to 0.20 joule after fractures per year in the United States 1,2 . The initial bone loss in the proxi- mal femur is of trabecularTrabecular Bone Contributes to Strength of the Proximal Femur Under Mediolateral Impact

Gefen, Amit

173

Pointless Mobilities: Rethinking Proximity Through the Loops of Neighbourhood  

Microsoft Academic Search

One of the important tasks of mobile sociology is to attend to the diverse proximities that are generated through the interplay of multiple forms of mobility. In answering to this challenge, mobilities researchers have illuminated how multiple forms of mobility have given rise to different physical and virtual proximities, involving corporal travel and new communication devices. However, in spite of

David Bissell

2012-01-01

174

Ranging/tracking system for proximity operations  

NASA Astrophysics Data System (ADS)

The hardware development and testing phase of a hand held radar for the ranging and tracking for Shuttle proximity operations are considered. The radar is to measure range to a 3 sigma accuracy of 1 m (3.28 ft) to a maximum range of 1850 m (6000 ft) and velocity to a 3 sigma accuracy of 0.03 m/s (0.1 ft/s). Size and weight are similar to hand held radars, frequently seen in use by motorcycle police officers. Meeting these goals for a target in free space was very difficult to obtain in the testing program; however, at a range of approximately 700 m, the 3 sigma range error was found to be 0.96 m. It is felt that much of this error is due to clutter in the test environment. As an example of the velocity accuracy, at a range of 450 m, a 3 sigma velocity error of 0.02 m/s was measured. The principles of the radar and recommended changes to its design are given. Analyses performed in support of the design process, the actual circuit diagrams, and the software listing are included.

Nilsen, P.; Udalov, S.

1982-06-01

175

Ranging/tracking system for proximity operations  

NASA Technical Reports Server (NTRS)

The hardware development and testing phase of a hand held radar for the ranging and tracking for Shuttle proximity operations are considered. The radar is to measure range to a 3 sigma accuracy of 1 m (3.28 ft) to a maximum range of 1850 m (6000 ft) and velocity to a 3 sigma accuracy of 0.03 m/s (0.1 ft/s). Size and weight are similar to hand held radars, frequently seen in use by motorcycle police officers. Meeting these goals for a target in free space was very difficult to obtain in the testing program; however, at a range of approximately 700 m, the 3 sigma range error was found to be 0.96 m. It is felt that much of this error is due to clutter in the test environment. As an example of the velocity accuracy, at a range of 450 m, a 3 sigma velocity error of 0.02 m/s was measured. The principles of the radar and recommended changes to its design are given. Analyses performed in support of the design process, the actual circuit diagrams, and the software listing are included.

Nilsen, P.; Udalov, S.

1982-01-01

176

Outcome of pyrocarbon proximal interphalangeal joint replacement.  

PubMed

Pyrocarbon arthroplasty of the proximal interphalangeal joint (PIPJ) has been reported to provide excellent pain relief when treating osteoarthritis of the hand. We retrospectively reviewed 20 PIPJ arthroplasties performed on 14 patients by a single surgeon using Ascension prosthesis. The mean follow up period was 3.5 years (range 1-7 years). Excellent pain relief was noted at the final follows-up. The mean range of motion improved from 40° pre-operatively to 70° post-operatively which was statistically significant. Twelve patients had significant improvement in quality of life and would consider similar procedure for other fingers. Radiological assessment revealed an average of 1 mm subsidence and there was no correlation noted between subsidence, migration and ROM at the final follow-up. Stiffness was the main complication and was comparable with other studies. The results of this series are encouraging and demonstrate excellent to good outcome in 86% of patients at the mid-term follow-up. PMID:24641745

Desai, Aravind; Gould, Fraser J; Mackay, David C

2014-01-01

177

Proximate industrial activity and psychological distress  

PubMed Central

This paper examines the role that gender, occupational status, and family status play in moderating the effect of industrial activity on the psychological well-being of nearby residents. Using a unique spatial assessment of industrial activity and an environmental risk/social stressor framework in conjunction with individual-level data from the Detroit Area Study (DAS) and demographic data from the U.S. census, we find that residents of neighborhoods in close proximity to industrial activity report elevated levels of psychological distress compared to residents of neighborhoods removed from this type of activity. These influences are more pronounced among women but gender differences are also contingent upon occupational and family statuses. We show that specific combinations of work and family statuses make persons particularly vulnerable to the influence of this environmental stressor and women are two and a half times more likely than men to have these vulnerable statuses. This study makes an important contribution to the environmental health literature because it reminds researchers of the fundamental influence of social roles when examining the link between environmental risks and mental health. PMID:19444334

Downey, Liam; Jackson, James S.; Merrill, J. Bryce; Saint Onge, Jarron M.; Williams, David R.

2009-01-01

178

Effects of thrust reversing in ground proximity  

NASA Technical Reports Server (NTRS)

The changes in stability and control characteristics encountered by a thrust reversing aircraft during its final approach, landing, and ground roll are described. These changes include a strong pitch-up accompanied by the loss of horizontal tail and aileron control effectiveness. The magnitude of reverser induced changes in ground effect are much larger than corresponding changes in free air. Some unexpected unsteady motions exhibited in wind tunnel by an aircraft model with reversers operating in ground proximity are also described. The cause of this oscillatory behavior was determined to be an unsteady interaction between the wall jets formed by impingement of reverser jets on the ground and the on-coming free stream. Time histories of rolling moments measured by the wind tunnel balance or support system were removed and frequencies were scaled by Strouhal number to full scale. Corrected time series were used to simulate the motion of a fighter aircraft with thrust reversers in ground effect. The simulation predicted large roll angles and nose down attitude at touchdown. Some phenomena of jet attachment to solid surfaces are discussed and areas for future research are recommended.

Joshi, P. B.; Hughes, R. V.

1987-01-01

179

Semiconductor detectors with proximity signal readout  

SciTech Connect

Semiconductor-based radiation detectors are routinely used for the detection, imaging, and spectroscopy of x-rays, gamma rays, and charged particles for applications in the areas of nuclear and medical physics, astrophysics, environmental remediation, nuclear nonproliferation, and homeland security. Detectors used for imaging and particle tracking are more complex in that they typically must also measure the location of the radiation interaction in addition to the deposited energy. In such detectors, the position measurement is often achieved by dividing or segmenting the electrodes into many strips or pixels and then reading out the signals from all of the electrode segments. Fine electrode segmentation is problematic for many of the standard semiconductor detector technologies. Clearly there is a need for a semiconductor-based radiation detector technology that can achieve fine position resolution while maintaining the excellent energy resolution intrinsic to semiconductor detectors, can be fabricated through simple processes, does not require complex electrical interconnections to the detector, and can reduce the number of required channels of readout electronics. Proximity electrode signal readout (PESR), in which the electrodes are not in physical contact with the detector surface, satisfies this need.

Asztalos, Stephen J. [XIA, LLC, Hayward, CA (United States)

2014-01-30

180

The Proximal Tubule and Albuminuria: Really!  

PubMed Central

Recent data highlight the role of the proximal tubule (PT) in reabsorbing, processing, and transcytosing urinary albumin from the glomerular filtrate. Innovative techniques and approaches have provided exciting insights into these processes, and numerous investigators have shown that selective PT cell defects lead to significant albuminuria, even reaching nephrotic range in animal models. Thus, the mechanisms of albumin reabsorption and transcytosis are undergoing intense study. Working in concert with megalin and cubilin, a nonselective multireceptor complex that predominantly directs proteins for lysosomal degradation, the neonatal Fc receptor (FcRn) located at the brush border of the apical membrane has been implicated as the “receptor” mediating albumin transcytosis. The FcRn pathway facilitates reabsorption and mediates transcytosis by its pH-dependent binding affinity in endosomal compartments. This also allows for selective albumin sorting within the PT cell. This reclamation pathway minimizes urinary losses and catabolism of albumin, thus prolonging its serum half-life. It may also serve as a molecular sorter to preserve and reclaim normal albumin while allowing “altered” albumin to be catabolized via lysosomal pathways. Here, we critically review the data supporting this novel mechanism. PMID:24408874

Dickson, Landon E.; Wagner, Mark C.; Sandoval, Ruben M.

2014-01-01

181

Scintillation Proximity Assay of Arginine Methylation  

PubMed Central

Methylation of arginine residues, catalyzed by protein arginine methyltransferases (PRMTs), is one important protein post-translational modification involved in epigenetic regulation of gene expression. A fast and effective assay for PRMT can provide valuable information for dissecting the biological functions of PRMTs, as well as for screening small-molecule inhibitors of arginine methylation. Currently, among the methods used for PRMT activity measurement, many contain laborious separation procedures, which restrict the applications of these assays for high-throughput screening (HTS) in drug discovery. The authors report here a mix-and-measure method to measure PRMT activity based on the principle of scintillation proximity assay (SPA). In this assay, 3H-AdoMet was used as methyl donor, and biotin-modified histone H4 peptide served as a methylation substrate. Following the methylation reaction catalyzed by PRMTs, streptavidin-coated SPA beads were added to the reaction solution, and SPA signals were detected by a MicroBeta scintillation counter. No separation step is needed, which simplifies the assay procedure and greatly enhances the assay speed. Particularly, the miniaturization and robustness suggest that this method is suited for HTS of PRMT inhibitors. PMID:21821785

Wu, Jiang; Xie, Nan; Feng, You; Zheng, Y. George

2011-01-01

182

Interactive orbital proximity operations planning system  

NASA Technical Reports Server (NTRS)

An interactive graphical proximity operations planning system was developed, which allows on-site design of efficient, complex, multiburn maneuvers in a dynamic multispacecraft environment. Maneuvering takes place in and out of the orbital plane. The difficulty in planning such missions results from the unusual and counterintuitive character of orbital dynamics and complex time-varying operational constraints. This difficulty is greatly overcome by visualizing the relative trajectories and the relevant constraints in an easily interpretable graphical format, which provides the operator with immediate feedback on design actions. The display shows a perspective bird's-eye view of a Space Station and co-orbiting spacecraft on the background of the Station's orbital plane. The operator has control over the two modes of operation: a viewing system mode, which enables the exporation of the spatial situation about the Space Station and thus the ability to choose and zoom in on areas of interest; and a trajectory design mode, which allows the interactive editing of a series of way points and maneuvering burns to obtain a trajectory that complies with all operational constraints. A first version of this display was completed. An experimental program is planned in which operators will carry out a series of design missions which vary in complexity and constraints.

Grunwald, Arthur J.; Ellis, Stephen R.

1988-01-01

183

Difference between hypertonic NaCl and NaHCO3 as osmotic diuretics in dog kidneys.  

PubMed

To compare the osmotic inhibitory effects of NaCl and NaHCO3 on proximal tubular fluid reabsorption, plasma osmolality was raised by 40 mosmol kg-1 H2O by infusing hypertonic NaCl and NaHCO3 in volume-expanded dogs receiving ethacrynic acid. In five dogs studied at constant plasma pH 7.5, both NaCl and NaHCO3 reduced water reabsorption by 29 +/- 2%. However, NaCl infusion reduced bicarbonate reabsorption by 31 +/- 2%, whereas bicarbonate reabsorption remained unchanged during NaHCO3 infusion. In six dogs, bicarbonate reabsorption was kept constant during NaCl and NaHCO3 infusion by adjustments of plasma pH. At similar glomerular filtration rates (42.4 +/- 2.9 ml min-1), water reabsorption was 28.7 +/- 1.7 ml min-1 in the control period, 29.4 +/- 2.5 ml min-1 during hypertonic NaCl infusion and 20.6 +/- 1.2 ml min-1 during hypertonic NaHCO3 infusion. Therefore, NaCl did not reduce proximal tubular water reabsorption by a direct osmotic effect. By calculating the regression coefficient for the relationship between measured chloride reabsorption and maximal convective chloride flux, the effective reflection coefficient for NaCl averaged 0.11 +/- 0.01. The combination of a low reflection coefficient and high permeability may explain why hypertonic NaCl is not an osmotic diuretic. PMID:2618758

Ostensen, J; Stokke, E S; Bugge, J F; Langberg, H; Kiil, F

1989-10-01

184

The influence of acetazolamide and amlodipine on the intracellular sodium content of rat proximal tubular cells.  

PubMed Central

1. This investigation set out to use 23Na n.m.r. spectroscopy to measure changes in intracellular levels of sodium in isolated suspensions of rat proximal tubules. The effects of temperature, an inhibitor of the sodium pump and known natriuretic drugs on intracellular sodium content of such tubular preparations were measured and compared with calcium channel antagonists where action at this level is unclear. 2. Rat kidneys were perfused with collagenase, roughly chopped, subjected to mechanical dispersion and washed to remove all traces of the enzyme. The proximal tubules were then purified and concentrated by Percoll density gradient centrifugation and then resuspended in buffer containing dysprosium tripolyphosphate shift reagent. 3. Distinct peaks corresponding to intracellular and extracellular sodium signals were observed when the tubules were placed into the n.m.r. spectrometer. As the temperature of the suspension rose to 37 degrees C, there was an exponential decrease in sodium content, with a decay constant of 0.15 +/- 0.02 min-1, which reached a stable level within 20 to 25 min. Addition of ouabain, 10(-3) M, resulted in a significant (P < 0.01) 30% increase in intracellular sodium content within 5 min which peaked at 70% 20 min later. Although acetazolamide (10(-3) M) significantly (P < 0.01) increased intracellular sodium content by 45%, amlodipine (10(-4) M) had no effect. 4. These data show that changes in the activity of the Na+/K+/ATPase have a considerable influence on the intracellular levels of sodium in proximal tubule cells.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7921616

Wong, P. S.; Barclay, P. L.; Newman, M. J.; Johns, E. J.

1994-01-01

185

Integrated Control of Na Transport along the Nephron.  

PubMed

The kidney filters vast quantities of Na at the glomerulus but excretes a very small fraction of this Na in the final urine. Although almost every nephron segment participates in the reabsorption of Na in the normal kidney, the proximal segments (from the glomerulus to the macula densa) and the distal segments (past the macula densa) play different roles. The proximal tubule and the thick ascending limb of the loop of Henle interact with the filtration apparatus to deliver Na to the distal nephron at a rather constant rate. This involves regulation of both filtration and reabsorption through the processes of glomerulotubular balance and tubuloglomerular feedback. The more distal segments, including the distal convoluted tubule (DCT), connecting tubule, and collecting duct, regulate Na reabsorption to match the excretion with dietary intake. The relative amounts of Na reabsorbed in the DCT, which mainly reabsorbs NaCl, and by more downstream segments that exchange Na for K are variable, allowing the simultaneous regulation of both Na and K excretion. PMID:25098598

Palmer, Lawrence G; Schnermann, Jürgen

2015-04-01

186

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

187

Hypospadias and Residential Proximity to Pesticide Applications  

PubMed Central

BACKGROUND: Experimental evidence suggests pesticides may be associated with hypospadias. OBJECTIVE: Examine the association of hypospadias with residential proximity to commercial agricultural pesticide applications. METHODS: The study population included male infants born from 1991 to 2004 to mothers residing in 8 California counties. Cases (n = 690) were ascertained by the California Birth Defects Monitoring Program; controls were selected randomly from the birth population (n = 2195). We determined early pregnancy exposure to pesticide applications within a 500-m radius of mother’s residential address, using detailed data on applications and land use. Associations with exposures to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for maternal race or ethnicity and age and infant birth year. RESULTS: Forty-one percent of cases and controls were classified as exposed to 57 chemical groups and 292 chemicals. Despite >500 statistical comparisons, there were few elevated odds ratios with confidence intervals that excluded 1 for chemical groups or specific chemicals. Those that did were for monochlorophenoxy acid or ester herbicides; the insecticides aldicarb, dimethoate, phorate, and petroleum oils; and adjuvant polyoxyethylene sorbitol among all cases; 2,6-dinitroaniline herbicides, the herbicide oxyfluorfen, and the fungicide copper sulfate among mild cases; and chloroacetanilide herbicides, polyalkyloxy compounds used as adjuvants, the insecticides aldicarb and acephate, and the adjuvant nonyl-phenoxy-poly(ethylene oxy)ethanol among moderate and severe cases. Odds ratios ranged from 1.9 to 2.9. CONCLUSIONS: Most pesticides were not associated with elevated hypospadias risk. For the few that were associated, results should be interpreted with caution until replicated in other study populations. PMID:24167181

Yang, Wei; Roberts, Eric M.; Kegley, Susan E.; Wolff, Craig; Guo, Liang; Lammer, Edward J.; English, Paul; Shaw, Gary M.

2013-01-01

188

Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis  

PubMed Central

Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2–dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity. PMID:24531551

Khan, Shenaz; Abu Jawdeh, Bassam G.; Goel, Monu; Schilling, William P.; Parker, Mark D.; Puchowicz, Michelle A.; Yadav, Satya P.; Harris, Raymond C.; El-Meanawy, Ashraf; Hoshi, Malcolm; Shinlapawittayatorn, Krekwit; Deschênes, Isabelle; Ficker, Eckhard; Schelling, Jeffrey R.

2014-01-01

189

Proximal gastrectomy with jejunal interposition and TGRY anastomosis for proximal gastric cancer  

PubMed Central

AIM: To compare the short-term outcomes of patients who underwent proximal gastrectomy with jejunal interposition (PGJI) with those undergoing total gastrectomy with Roux-en-Y anastomosis (TGRY). METHODS: From January 2009 to January 2011, thirty-five patients underwent PGJI, and forty-one patients underwent TGRY. The surgical efficacy and short-term follow-up outcomes were compared between the two groups. RESULTS: There were no differences in the demographic and clinicopathological characteristics. The mean operation duration and postoperative hospital stay in the PGJI group were statistically longer than those in the TGRY group (P = 0.00). No anastomosis leakage was observed in two groups. No statistically significant difference was found in endoscopic findings, Visick grade or serum albumin level. The single-meal food intake in the PGJI group was more than that in the TGRY group (P = 0.00). The PG group showed significantly better hemoglobin levels in the second year (P = 0.02). The two-year survival rate was not significantly different (PGJI vs TGRY, 93.55% vs 92.5%, P = 1.0). CONCLUSION: PGJI is a safe, radical surgical method for proximal gastric cancer and leads to better outcomes in terms of the single-meal food intake and hemoglobin level, compared with TGRY in the short term. PMID:25009402

Zhao, Ping; Xiao, Shuo-Meng; Tang, Ling-Chao; Ding, Zhi; Zhou, Xiang; Chen, Xiao-Dong

2014-01-01

190

Alterations in membrane transport function and cell viability induced by ATP depletion in primary cultured rabbit renal proximal tubular cells.  

PubMed

This study was undertaken to elucidate the underlying mechanisms of ATP depletion-induced membrane transport dysfunction and cell death in renal proximal tubular cells. ATP depletion was induced by incubating cells with 2.5 mM potassium cyanide (KCN)/0.1 mM iodoacetic acid (IAA), and membrane transport function and cell viability were evaluated by measuring Na(+)-dependent phosphate uptake and trypan blue exclusion, respectively. ATP depletion resulted in a decrease in Na(+)-dependent phosphate uptake and cell viability in a time-dependent manner. ATP depletion inhibited Na(+)-dependent phosphate uptake in cells, when treated with 2 mM ouabain, a Na(+) pump-specific inhibitor, suggesting that ATP depletion impairs membrane transport functional integrity. Alterations in Na(+)-dependent phosphate uptake and cell viability induced by ATP depletion were prevented by the hydrogen peroxide scavenger such as catalase and the hydroxyl radical scavengers (dimethylthiourea and thiourea), and amino acids (glycine and alanine). ATP depletion caused arachidonic acid release and increased mRNA levels of cytosolic phospholipase A(2) (cPLA(2)). The ATP depletion-dependent arachidonic acid release was inhibited by cPLA(2) specific inhibitor AACOCF(3). ATP depletion-induced alterations in Na(+)-dependent phosphate uptake and cell viability were prevented by AACOCF(3). Inhibition of Na(+)-dependent phosphate uptake by ATP depletion was prevented by antipain and leupetin, serine/cysteine protease inhibitors, whereas ATP depletion-induced cell death was not altered by these agents. These results indicate that ATP depletion-induced alterations in membrane transport function and cell viability are due to reactive oxygen species generation and cPLA(2) activation in renal proximal tubular cells. In addition, the present data suggest that serine/cysteine proteases play an important role in membrane transport dysfunction, but not cell death, induced by ATP depletion. PMID:19885021

Lee, Sung Ju; Kwon, Chae Hwa; Kim, Yong Keun

2009-02-01

191

76 FR 63238 - Proximity Detection Systems for Continuous Mining Machines in Underground Coal Mines  

Federal Register 2010, 2011, 2012, 2013, 2014

...1219-AB65 Proximity Detection Systems for Continuous Mining Machines in Underground Coal...addressing Proximity Detection Systems for Continuous Mining Machines in Underground Coal...rule for Proximity Detection Systems on Continuous Mining Machines in Underground...

2011-10-12

192

76 FR 70075 - Proximity Detection Systems for Continuous Mining Machines in Underground Coal Mines  

Federal Register 2010, 2011, 2012, 2013, 2014

...1219-AB65 Proximity Detection Systems for Continuous Mining Machines in Underground Coal...addressing Proximity Detection Systems for Continuous Mining Machines in Underground Coal...rule, Proximity Detection Systems for Continuous Mining Machines in Underground...

2011-11-10

193

Proximity to Urban Parks and Mental Health  

PubMed Central

Background Urban parks have received attention in recent years as a possible environmental factor that could encourage physical activity, prevent obesity, and reduce the incidence of chronic conditions. Despite long hypothesized benefits of parks for mental health, few park studies incorporate mental health measures. Aims of the Study To test the association between proximity to urban parks and psychological distress. Methods Cross-sectional analysis of individual health survey responses. Data were collected for a study of capital improvements of neighborhood parks in Los Angeles. A survey was fielded on a sample of residential addresses, stratified by distance from the park (within 400m, 800m, 1.6 km, and 3.2km; N=1070). We used multiple regression to estimate the relationship between the psychological distress as measured by the MHI-5 (outcome variable) and distance to parks (main explanatory variable), controlling for observed individual characteristics. Results Mental health is significantly related to residential distance from parks, with the highest MHI-5 scores among residents within short walking distance from the park (400m) and decreasing significantly over the next distances. The number of visits and physical activity minutes are significantly and independently related to distance, although controlling for them does not reduce the association between distance and mental health. Discussion and Limitations This paper provides a new data point for an arguably very old question, but for which empirical data are sparse for the US. A nearby urban park is associated with the same mental health benefits as decreasing local unemployment rates by 2 percentage points, suggesting at least the potential of environmental interventions to improve mental health. The analysis is cross-sectional, making it impossible to control for important confounders, including residential selection. Implications for Health Policy Mental health policy has traditionally focused on individual-centered interventions. Just as health policy for preventable chronic illnesses has shifted attention to modifiable environmental determinants, population mental health may benefit substantially from environmental interventions. Implications for Future Research Policy evaluations should incorporate mental health measures when assessing neighborhood improvement programs and physical environments. Many recent and ongoing studies have excluded mental health measure in the belief that they are too burdensome for respondents or irrelevant. If a causal relationship is confirmed, then ameliorating neighborhood conditions and physical environments could represent a scalable way to improve mental health issues for large populations. PMID:24864118

Sturm, Roland; Cohen, Deborah

2014-01-01

194

Regulation of an Inwardly Rectifying ATP-sensitive K+ Channel in the Basolateral Membrane of Renal Proximal Tubule  

PubMed Central

Functional coupling of Na+,K+-ATPase pump activity to a basolateral membrane (BLM) K+ conductance is crucial for sustaining transport in the proximal tubule. Apical sodium entry stimulates pump activity, lowering cytosolic [ATP], which in turn disinhibits ATP-sensitive K+ (KATP) channels. Opening of these KATP channels mediates hyperpolarization of the BLM that facilitates Na+ reabsorption and K+ recycling required for continued Na+,K+-ATPase pump turnover. Despite its physiological importance, little is known about the regulation of this channel. The present study focuses on the regulation of the BLM KATP channel by second messengers and protein kinases using membrane patches from dissociated, polarized Ambystoma proximal tubule cells. The channel is regulated by protein kinases A and C, but in opposing directions. The channel is activated by forskolin in cell-attached (c/a) patches, and by PKA in inside-out (i/o) membrane patches. However, phosphorylation by PKA is not sufficient to prevent channel rundown. In contrast, the channel is inhibited by phorbol ester in c/a patches, and PKC decreases channel activity (nPo) in i/o patches. The channel is pH sensitive, and lowering cytosolic pH reduces nPo. Increasing intracellular [Ca2+] ([Ca2+]i) in c/a patches decreases nPo, and this effect is direct since [Ca2+]i inhibits nPo with a Ki of ?170 nM in i/o patches. Membrane stretch and hypotonic swelling do not significantly affect channel behavior, but the channel appears to be regulated by the actin cytoskeleton. Finally, the activity of this BLM KATP channel is coupled to transcellular transport. In c/a patches, maneuvers that inhibit turnover of the Na+,K+-ATPase pump reduce nPo, presumably due to a rise in intracellular [ATP], although the associated cell depolarization cannot be ruled out as the possible cause. Conversely, stimulation of transport (and thus pump turnover) leads to increases in nPo, presumably due to a fall in intracellular [ATP]. These results show that the inwardly rectifying KATP channel in the BLM of the proximal tubule is a key element in the feedback system that links cellular metabolism with transport activity. We conclude that coupling of this KATP channel to the activity of the Na+,K+-ATPase pump is a mechanism by which steady state NaCl reabsorption in the proximal tubule may be maintained. PMID:9417142

Mauerer, Ulrich R.; Boulpaep, Emile L.; Segal, Alan S.

1998-01-01

195

Analysis on the characteristics of pulsed laser proximity fuze's echo  

NASA Astrophysics Data System (ADS)

With the rapid development of semiconductor technology and laser technology, a kind of proximity fuze named pulsed laser proximity fuze has been applied. Compared with other fuzes, pulsed laser proximity fuze has high ranging precision and strong resistance to artificial active interference. It is an important development tendency of proximity fuze. The paper analyze the characteristic of target echo of laser signal, and then make theoretical analysis and calculation on the laser signal transmission in the smog. Firstly, use the pulse width of 10ns semiconductor laser fuze to do typical targets experiment, to get the echo information of target distance is 5m; then to do smog interference experiment, by comparing the pulse width amplitude and backscattering signal amplitude of laser fuze in simulation and experiment, analyzing the effect of anti-clutter, providing the evidence for the subsequent of circuit of signal amplification and processing.

Wang, Kun; Chen, Huimin

2011-06-01

196

Light-operated proximity detector with linear output  

DOEpatents

A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phototransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

Simpson, Marc L. (Harriman, TN); McNeilly, David R. (Maryville, TN)

1985-01-01

197

Light-operated proximity detector with linear output  

DOEpatents

A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phtotransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

Simpson, M.L.; McNeilly, D.R.

1984-01-01

198

Inferior vena cava filter penetration into right proximal ureter.  

PubMed

Inferior vena cava (IVC) filter penetration into the renal collecting system is an infrequent event. We report a case of IVC filter penetration into the right proximal ureter resulting in gross hematuria, hydronephrosis and stone formation. PMID:24529023

Sherman, Christopher M; Rao, Sandhya R; Talluri, Sriharsha; Dwivedi, Amit J; Ankem, Murali K

2014-02-01

199

Proximal Corpus Cavernosum Tear Presenting as Scrotal Hematoma  

PubMed Central

We present the case of a penile fracture involving the proximal corpus cavernosum, presenting as a hematoma extending into the scrotum. The presentation, diagnosis, and surgical approach, which differ from the more typical penile shaft fracture, are delineated. PMID:23781385

Darves-Bornoz, A.; DeBartolo, M. M.; Mishail, A. M.

2013-01-01

200

Deleting the TGF-? receptor attenuates acute proximal tubule injury.  

PubMed

TGF-? is a profibrotic growth factor in CKD, but its role in modulating the kidney's response to AKI is not well understood. The proximal tubule epithelial cell, which is the main cellular target of AKI, expresses high levels of both TGF-? and its receptors. To determine how TGF-? signaling in this tubular segment affects the response to AKI, we selectively deleted the TGF-? type II receptor in the proximal tubules of mice. This deletion attenuated renal impairment and reduced tubular apoptosis in mercuric chloride-induced injury. In vitro, deficiency of the TGF-? type II receptor protected proximal tubule epithelial cells from hydrogen peroxide-induced apoptosis, which was mediated in part by Smad-dependent signaling. Taken together, these results suggest that TGF-? signaling in the proximal tubule has a detrimental effect on the response to AKI as a result of its proapoptotic effects. PMID:23160515

Gewin, Leslie; Vadivelu, Sangeetha; Neelisetty, Surekha; Srichai, Manakan B; Paueksakon, Paisit; Pozzi, Ambra; Harris, Raymond C; Zent, Roy

2012-12-01

201

75 FR 5009 - Proximity Detection Systems for Underground Mines  

Federal Register 2010, 2011, 2012, 2013, 2014

...Systems Proximity detection is a technology that uses electronic sensors to detect motion or the location of one object relative to...mid 1990s to present day. The technologies include radio, ultrasonic, radar, infrared, and electromagnetic field based...

2010-02-01

202

A proximal multiplier method for separable convex minimization  

E-print Network

unified the work of Chen and Teboulle (PCPM method), Kyono and ..... the induced proximal distance to d if there exists ? ? (0,1] with H a finite valued ...... problems via finite element approximations, Computers and Mathematics with Appli-.

2014-07-03

203

Computer vision based navigation for spacecraft proximity operations  

E-print Network

The use of computer vision for spacecraft relative navigation and proximity operations within an unknown environment is an enabling technology for a number of future commercial and scientific space missions. This thesis ...

Tweddle, Brent Edward

2010-01-01

204

Technical tips: dualplate fixation technique for comminuted proximal humerus fractures.  

PubMed

The authors report dualplate fixation technique for providing stable fixation in comminuted proximal humerus fractures. This technique has been used for proximal humerus fractures with metaphyseal comminution and provides excellent anatomical reduction and neck shaft angle (NSA). The recently locking plate is clinically more widely used due to its small size, low rigidity, high elasticity, and biomechanical properties such as fixed initial angle and rotational stability. However, in severely comminuted complex type proximal metaphyseal humerus fractures, the use of locking plate alone does not provide stable fixation, leading to complications such as varus collapse, anterior-posterior angulation, screw cutout, nonunion, malunion, and metal failure. Therefore, a more robust and enhanced fixation method, the dual plating technique using the locking compression plate (Proximal Humeral Internal Locking System and Variable Angle Locking Compression Plate) was developed. PMID:24813097

Choi, Sungwook; Kang, Hyunseong; Bang, Hyeongsig

2014-08-01

205

Proximal nerve conduction studies in chronic inflammatory demyelinating polyneuropathy  

Microsoft Academic Search

ObjectiveThe purpose of this study was to evaluate the sensitivity and specificity of proximal upper limb motor nerve conduction study abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP), using standard percutaneous stimulations up to Erb’s point.

Yusuf A. Rajabally; Saiju Jacob

2006-01-01

206

VCSEL-based microsensors for photonic proximity fuzing of munitions  

Microsoft Academic Search

This paper describes technologies developed at Sandia National Laboratories to support a joint DoD\\/DoE initiative to create a compact, robust, and affordable photonic proximity sensor for munitions fuzing. The proximity fuze employs high-power vertical-cavity surface-emitting laser (VCSEL) arrays, resonant-cavity photodetectors (RCPDs), and refractive micro-optics that are integrated within a microsensor whose volume is approximately 0.01 cm3. Successful development and integration

G. A. Keeler; A. Mar; K. M. Geib; A. Y. Hsu; D. K. Serkland; G. M. Peake

2008-01-01

207

Outcomes of one-stage techniques for proximal hypospadias repair  

Microsoft Academic Search

Objectives. To evaluate the success of three preputial flap techniques in the one-stage correction of proximal hypospadias.Methods. From 1993 to 1999, 43 children underwent one-stage proximal hypospadias repair using preputial flaps, which were performed by a single surgeon. Of the 43 patients, 21 (48.8%), 10 (23.2%), and 12 (27.9%) underwent tubularized island flap urethroplasty, double-faced tubularized island flap urethroplasty, and

Turan Kanmaz; Selçuk Yücesan

2001-01-01

208

Predictors of Proximal Neoplasia in Patients Without Distal Adenomatous Pathology  

Microsoft Academic Search

BACKGROUND:Previous colorectal cancer screening studies have observed that some patients may have advanced proximal neoplasia without distal findings. Since these studies have included only gender, age, and family history as risk factors, they are limited in their ability to identify predictors of isolated proximal neoplasia.METHODS:Data were collected from the charts of 1,988 patients who presented for colonoscopy. Information gathered included

Joseph C. Anderson; Zvi Alpern; Catherine R. Messina; Patricia Hubbard; Roger Grimson; Peter F. Ells; Douglas L. Brand

2004-01-01

209

Saccharomyces boulardii upgrades cellular adaptation after proximal enterectomy in rats  

Microsoft Academic Search

BACKGROUNDSaccharomyces boulardii is a non-pathogenic yeast which exerts trophic effects on human and rat small intestinal mucosa.AIMSTo examine the effects of S boulardii on ileal adaptation after proximal enterectomy in rats.METHODSWistar rats, aged eight weeks, underwent 60% proximal resection or transection and received by orogastric intubation either 1 mg\\/g body wt per day lyophilised S boulardii or the vehicle for

J-P Buts; N De Keyser; S Marandi; D Hermans; E M Sokal; Y-H E Chae; L Lambotte; H Chanteux; P M Tulkens

1999-01-01

210

Digital Image Enhancement Improves Diagnosis of Nondisplaced Proximal Femur Fractures  

Microsoft Academic Search

Today most emergency room radiographs are computerized, making digital image enhancement a natural advancement to improve\\u000a fracture diagnosis. We compared the diagnosis of nondisplaced proximal femur fractures using four different image enhancement\\u000a methods using standard DICOM (Digital Imaging and Communications in Medicine) after window-leveling optimization. Twenty-nine\\u000a orthopaedic residents and specialists reviewed 28 pelvic images consisting of 25 occult proximal femur

Itamar Busheri Botser; Amir Herman; Ram Nathaniel; Dan Rappaport; Aharon Chechik

2009-01-01

211

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

212

The renal Na+/Ca2+ exchange system is located exclusively in the distal tubule.  

PubMed Central

The movement of Ca2+ across the basolateral plasma membrane was determined in purified preparations of this membrane isolated from rabbit proximal and distal convoluted tubules. The ATP-dependent Ca2+ uptake was present in basolateral membranes from both these tubular segments, but the activity was higher in the distal tubules. A very active Na+/Ca2+ exchange system was also demonstrated in the distal-tubular membranes, but in proximal-tubular membranes this exchange system was not demonstrable. The presence of Na+ outside the vesicles gradually inhibited the ATP-dependent Ca2+ uptake in the distal-tubular-membrane preparations, but remained without effect in those from the proximal tubules. The activity of the Na+/Ca2+ exchange system in the distal-tubular membranes was a function of the imposed Na+ gradient. These results suggest that the major differences in the characteristics of Ca2+ transport in the proximal and in the distal tubules are due to the high activity of a Na+/Ca2+ exchange system in the distal tubule and its virtual absence in the proximal tubule. PMID:2920016

Ramachandran, C; Brunette, M G

1989-01-01

213

Na/sup +/-H/sup +/ exchange and Na/sup +/-dependent transport systems in streptozotocin diabetic rat kidneys  

SciTech Connect

The streptozotocin-induced diabetic rat was used to test the hypothesis that Na/sup +/-H/sup +/ exchange activity in the proximal tubule luminal membrane would be increased in association with renal hypertrophy, altered glomerular hemodynamics, enhanced filtered load and tubular reabsorption of /sup 22/Na/sup +/, and stimulated /sup 22/Na= pump activity in the basolateral membrane, previously reported characteristics of this experimental animal model. Amiloride-sensitive H/sup +/ gradient-dependent Na/sup +/ uptake and Na/sup +/ gradient-dependent H/sup +/ flux were increased in brush-border membrane vesicles from the streptozotocin-treated animals. Na/sup +/ gradient-dependent uptakes of phosphate, D-glucose, L-proline, and myoinositol were decreased in the drug-induced diabetic animals. These membrane transport alterations were not found when the streptozotocin-diabetic animals were treated with insulin.

El-Seifi, S.; Freiberg, J.M.; Kinsella, F.J.; Cheng, L.; Sacktor, B.

1987-01-01

214

Oral sodium bicarbonate reduces proximal renal tubular peptide catabolism, ammoniogenesis, and tubular damage in renal patients.  

PubMed

Oral sodium bicarbonate (NaHCO3) is widely used to treat acidosis in patients with renal failure. However, no data are available in man on the effects on proximal renal tubular protein catabolism or markers of tubular injury. We have developed methods to allow such studies, and both increased tubular catabolism of 99mTc-labelled aprotinin (Apr*), as well as tubular damage were found in association with increased ammonia (NH3) excretion in patients with nephrotic range proteinuria. We now examine the effects of reducing renal ammoniogenesis, without altering proteinuria, using oral NaHCO3 in 11 patients with mild/moderate renal impairment and proteinuria. Renal tubular catabolism of Apr* was measured before and after NaHCO3 by renal imaging (Kidney uptake, K% of dose) and urinary excretion of free 99mTcO4- (metabolism, Met% of dose/h) over 26 h. Fractional degradation (Frac) was calculated from Met/K (/h). Fresh urine was also analyzed for NH3 excretion every fortnight from 6/52 before treatment. Total urinary N-acetyl-beta-D-glucose-aminidase (NAG) and the more tubulo-specific NAG "A2" were measured. 51CrEDTA clearance and 99mTc-MAG 3 TER were also assessed. After NaHCO3 Met over 26 h was significantly reduced (from 1.3 +/- 0.2% of dose/h to 0.9 +/- 0.1% dose/hr, p < 0.005), as was Frac of Apr* (from 0.06 +/- .006/h to 0.04 +/- 0.005/hr, p < 0.003). NH3 excretion also fell significantly (from 0.9 +/- 0.2 mmol/h to 0.2 +/- 0.05 mmol/h, p < 0.007), as did both total urinary NAG (from 169 mumol/24 h, 74-642 mumol/24 h to 79 mumol/ 24 h, 37-393 mumol/24 h, p < 0.01), and the NAG 'A2' isoenzyme (from 81.5 mumol/24 h, 20-472 mumol/24 h to 35.0 mumol/24 h, 6-388 mumol/24 h, p < 0.001). Proteinuria remained unaltered, and there was no change in blood pressure nor in glomerular haemodynamics. Oral NaHCO3 may thus pro-tect the proximal renal tubule and help delay renal disease progression. PMID:9574465

Rustom, R; Grime, J S; Costigan, M; Maltby, P; Hughes, A; Taylor, W; Shenkin, A; Critchley, M; Bone, J M

1998-03-01

215

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

216

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

217

Orthopaedic Approaches to Proximal Humeral Fractures Following Trauma  

PubMed Central

Proximal humeral fractures have been a topic of discussion in medical literature dating back as far as 3rd century BC. Today, these fractures are the most common type of humeral fractures and account for about 5-6% of all fractures in adults with the incidence rising rapidly with age. In broad terms the management of proximal humeral fractures can be divided into two categories: conservative versus surgical intervention. The aim of treatment is to stabilize the fracture, aid better union and reduce pain during the healing process. Failure to achieve this can result in impairment of function, and significantly weaken the muscles inserting onto the proximal humerus. With the rising incidence of proximal humeral fractures, especially among the elderly, the short and long term burden for patients as well as the wider society is increasing. Furthermore, there is a lack of consistency in the definitive treatment and management of displaced fractures. This systematic review of literature compares the surgical treatment of proximal humeral fractures with their conservative management, by evaluating the available randomised controlled trials on this topic. PMID:25408786

Mafi, Reza; Khan, Wasim; Mafi, Pouya; Hindocha, Sandip

2014-01-01

218

Proximal femur fractures: the pioneer era of 1818 to 1925.  

PubMed

The foundations of the modern era of the treatment of proximal femur fractures were laid by Cooper who in 1819 published the first therapeutically oriented classification of these fractures. During the following 100 years the clinical diagnostics were further developed; five classifications of proximal femur fractures were formulated including the terminology used until now (peritrochanteric, intertrochanteric), and surgical treatment was started. The first attempt at internal fixation of the proximal femur in the 1850s was by Langenbeck. His patient died of sepsis. The first successful internal fixation of proximal femur fractures was done in 1875 by König. At the beginning of the twentieth century the method of surgical treatment for proximal femur fractures was improved by Lambotte, Delbet, and Putti. However, the time was not ready yet for this method of treatment. Only technologic progress (stainless steel, new technology), the additional development of anesthesia and asepsis, improvement of xray apparatus, and introduction of the traction table created the prerequisites for successful gradation of Smith-Petersen's method from 1925 to 1931, and which a few years later was used worldwide. PMID:15021169

Bartonícek, Jan

2004-02-01

219

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

220

The action of angiotensin II on the intracellular sodium content of suspensions of rat proximal tubules.  

PubMed Central

1. Intracellular sodium levels in isolated suspensions of rat proximal tubles were measured by 23Na NMR spectroscopy and the effect of angiotensin II (AII) on these levels was recorded. 2. AII at 10(-11) M produced an increase in intracellular sodium content of approximately 20% (P < 0.001) from the steady-state level 5 min after the addition of the drug; intracellular sodium content then gradually returned to baseline levels over the subsequent 25 min. 3. Addition of AII at 10(-5) M resulted in a significant 20% decrease (P < 0.01) in the steady-state intracellular sodium level within 5 min. Again the effect was transient and steady-state intracellular sodium levels were re-established after 25 min. 4. Amiloride at 10(-4) M significantly attenuated the action of AII at 10(-11) M (P < 0.0001) and inhibited the transient response to AII at 10(-5) M (P < 0.01). When amiloride alone was added to the tubular suspension, intracellular sodium content decreased significantly by 18-22% (P < 0.001), and addition of both the high and low doses of AII did not have any further effect on intracellular sodium level. 5. The actions of both concentrations of AII were unaffected by an inhibitor of endopeptidase-24.11, phosphoramidon at 10(-6) M, which suggests that the transient action of AII was not due to the breakdown of AII by endopeptidase-24.11. 6. It is well known that AII at high doses inhibits and at low doses stimulates sodium transport across proximal tubular epithelial cells. From the present data it is proposed that AII has a transient biphasic action on intracellular sodium content which may reflect the stimulation of the Na(+)-H+ exchanger. PMID:8951724

Wong, P S; Johns, E J

1996-01-01

221

VCSEL-based microsensors for photonic proximity fuzing of munitions  

NASA Astrophysics Data System (ADS)

This paper describes technologies developed at Sandia National Laboratories to support a joint DoD/DoE initiative to create a compact, robust, and affordable photonic proximity sensor for munitions fuzing. The proximity fuze employs high-power vertical-cavity surface-emitting laser (VCSEL) arrays, resonant-cavity photodetectors (RCPDs), and refractive micro-optics that are integrated within a microsensor whose volume is approximately 0.01 cm3. Successful development and integration of these custom photonic components should enable a g-hard photonic proximity fuze that replaces costly assemblies of discrete lasers, photodetectors, and bulk optics. Additional applications of this technology include void sensing, ladar and short-range 3-D imaging.

Keeler, G. A.; Mar, A.; Geib, K. M.; Hsu, A. Y.; Serkland, D. K.; Peake, G. M.

2008-08-01

222

DNA replication-dependent induction of gene proximity by androgen.  

PubMed

The male hormone androgen, working through the androgen receptor (AR), plays a major role in physiological process and disease development. Previous studies of AR mainly focus on its transcriptional activity. Here, we found that androgen-induced TMPRSS2 and ERG gene proximity is mediated by AR control of DNA replication rather than gene transcription. We demonstrate that, in both AR transactivation-positive and -negative prostate cells, androgen regulates DNA replication and androgen-induced gene proximity relies on both DNA replication-licensing and actual DNA replication activity. Androgen stimulation advances DNA replication timing of certain genomic regions, which may potentially increase gene proximity through sharing the same replication factory at a similar time. Therefore, we have revealed novel mechanisms of AR biological function, which will stimulate new research directions. PMID:25281662

Coll-Bastus, Nuria; Mao, Xueying; Young, Bryan D; Sheer, Denise; Lu, Yong-Jie

2015-02-15

223

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. PMID:22399923

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

2010-01-01

224

Reverse geometry shoulder replacement for proximal humeral metastases.  

PubMed

The management of skeletal metastases can be challenging for the orthopaedic surgeon. They represent a significant source of pain and disability for cancer patients, adding to the morbidity of their condition. Treatment is directed at the alleviation of symptoms and the restoration of function. Metastatic involvement of the proximal humerus can be especially debilitating, having the potential to cause severe pain and loss of function. We present a report of three such cases where reverse geometry proximal shoulder replacement was used to provide a pain free functional range of movement in patients with concomitant rotator cuff disease. In all cases, significant symptomatic relief was achieved postoperatively with preservation of upper limb function. No surgical complications were noted. It is our belief that this novel surgical strategy provides a valuable and effective option for the management of proximal humeral metastatic disease in the rotator cuff deficient patient. PMID:25245723

Kapur, R A; McCann, P A; Sarangi, P P

2014-10-01

225

Comparison of distal and proximal centralising devices in hip arthroplasty  

PubMed Central

Centralising devices were introduced to ensure that the prosthesis is implanted in a neutral position and that a cement mantle of optimal thickness is achieved proximally and distally. A distal centralising device (DCD) is compared with a proximal midshaft centralising device (PCD) to test which one provides a more neutral prosthetic alignment. Thirty consecutive patients undergoing hemiarthroplasties for femoral neck fractures were studied prospectively. Patients were blindly randomised to receive either a femoral component with proximal midshaft centraliser or distal centraliser. Both components were implanted following the manufacturer’s protocol. Postoperative true anteroposterior and lateral radiographs were made to assess the stem position. There was no statistically significant difference between the two groups in zones 1, 2, 3, 4, 5, 6 and 7 in both anteroposterior and lateral radiographic measurements. DCP and PCD both have similar centralisation and cement mantle. Future studies should be done to evaluate their long-term effect. PMID:18712387

Bezer, M.; Akgulle, A. H.; Saygi, B.; Kocao?lu, B.; Guven, O.

2008-01-01

226

Common relationships among proximate composition components in fishes  

USGS Publications Warehouse

Relationships between the various body proximate components and dry matter content were examined for five species of fishes, representing anadromous, marine and freshwater species: chum salmon Oncorhynchus keta, Chinook salmon Oncorhynchus tshawytscha, brook trout Salvelinus fontinalis, bluefish Pomatomus saltatrix and striped bass Morone saxatilis. The dry matter content or per cent dry mass of these fishes can be used to reliably predict the per cent composition of the other components. Therefore, with validation it is possible to estimate fat, protein and ash content of fishes from per cent dry mass information, reducing the need for costly and time-consuming laboratory proximate analysis. This approach coupled with new methods of non-lethal estimation of per cent dry mass, such as from bioelectrical impedance analysis, can provide non-destructive measurements of proximate composition of fishes. ?? 2008 The Authors.

Hartman, K.J.; Margraf, F.J.

2008-01-01

227

Proximal row carpectomy with allograft scaffold interposition arthroplasty.  

PubMed

The authors present a solution for motion preservation in severe wrist arthritis with intercarpal involvement. Acellular dermal allograft is used as an interposition arthroplasty in these situations, rather than local tissue flaps such as previously described. Proximal row carpectomy has been shown to be one of the most successful procedures to correct chronic destructive arthritis in the wrist, keeping useful motion. Traditionally, a contraindication for proximal row carpectomy includes an arthritis that invades the lunate-capitate joint. The authors describe a technique to extend the traditional indications by covering the eroded articular surfaces with dermal allograft scaffold. PMID:22105639

Carneiro, Ronaldo dos Santos; Dias, Carlos Eduardo Baião Nogueira Maia; Baptista, Carolina Moutinho Peneda Morais

2011-12-01

228

Evolution and proximate expression of human paternal investment.  

PubMed

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 the physical and social well-being of children are reviewed in light of the social and ecological factors that are associated with paternal investment in other species. On the basis of this review, discussion of the evolution and proximate expression of human paternal investment is provided. PMID:10668350

Geary, D C

2000-01-01

229

Ectrodactyly and proximal/intermediate interstitial deletion 7q  

SciTech Connect

We report on an individual with severe mental retardation, seizures, microcephaly, unusual face, scoliosis, and cleft feet and cleft right hand. The chromosomal study showed a proximal interstitial deletion 7q (q11.23q22). From our review of the literature, 11 patients have been reported with ectrodactyly (split hand/split foot malformation) and proximal/intermediate interstitial deletions or rearrangements of 7q. The critical segment for ectrodactyly seems to be located between 7q21.2 and 7q22.1. This malformation is present in 41% of the patients whose deletion involves the critical segment. 37 refs., 3 figs., 1 tab.

McElveen, C.; Carvajal, M.V.; Moscatello, D. [Louisiana State Univ. Medical Center, New Orleans, LA (United States)] [and others

1995-03-13

230

An experiment in manipulator control with proximity sensors  

NASA Technical Reports Server (NTRS)

Optical proximity sensors were used in a feedback loop to automatically position a manipulator hand for grasping. The experiment was a simplified one, involving two dimensional motion only. Two proximity sensors were mounted on the hand, and control signals derived from their outputs were used to drive the hand vertically and horizontally. The sensors employ a pulsed gallium arsenide light-emitting diode together with a silicon detector. They indicate, without contact, the approximate distance between the manipulator hand and object in the range from 5 to 12 cm. Positioning within approximately + or - 5 mm was observed. Extension of the technique to general three-dimensional control is briefly discussed.

Johnston, A. R.

1974-01-01

231

Proximal antecedents to violent events in adolescent dating relationships.  

PubMed

Dating violence affects 25-60% of adolescents. This study developed a typology of proximal antecedents to violent events in adolescent dating relationships. Descriptions of 307 dating violence events were extracted from transcribed interviews with 87 young adults who experienced dating violence as adolescents. Verbatim text preceding the description of each violent event was identified as a proximal antecedent. Cross-case analysis was used to develop a typology of five antecedent categories: "pulling away,"  "demanding obedience," "discovering involvement with a rival," "defining the relationship," "demonstrating disrespect." Practitioners can use this typology to engage teens in discussions of factors that precede dating violence events. PMID:21992258

Stephenson, Pamela S; Martsolf, Donna S; Draucker, Claire Burke

2011-01-01

232

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

233

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. PMID:22647968

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

2012-01-01

234

Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) Rendezvous Proximity Operations Design and Trade Studies  

NASA Astrophysics Data System (ADS)

The Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) program is to demonstrate rendezvous proximity operations (RPO), formation flying, and docking with a pair of 3U CubeSats. The program is sponsored by NASA Ames via the Office of the Chief Technologist (OCT) in support of its Small Spacecraft Technology Program (SSTP). The goal of the mission is to demonstrate complex RPO and docking operations with a pair of low-cost 3U CubeSat satellites using passive navigation sensors. The program encompasses the entire system evolution including system design, acquisition, satellite construction, launch, mission operations, and final disposal. The satellite is scheduled for launch in Fall 2015 with a 1-year mission lifetime. This paper provides a brief mission overview but will then focus on the current design and driving trade study results for the RPO mission specific processor and relevant ground software. The current design involves multiple on-board processors, each specifically tasked with providing mission critical capabilities. These capabilities range from attitude determination and control to image processing. The RPO system processor is responsible for absolute and relative navigation, maneuver planning, attitude commanding, and abort monitoring for mission safety. A low power processor running a Linux operating system has been selected for implementation. Navigation is one of the RPO processor's key tasks. This entails processing data obtained from the on-board GPS unit as well as the on-board imaging sensors. To do this, Kalman filters will be hosted on the processor to ingest and process measurements for maintenance of position and velocity estimates with associated uncertainties. While each satellite carries a GPS unit, it will be used sparsely to conserve power. As such, absolute navigation will mainly consist of propagating past known states, and relative navigation will be considered to be of greater importance. For relative observations, each spacecraft hosts 3 electro-optical sensors dedicated to imaging the companion satellite. The image processor will analyze the images to obtain estimates for range, bearing, and pose, with associated rates and uncertainties. These observations will be fed to the RPO processor's relative Kalman filter to perform relative navigation updates. This paper includes estimates for expected navigation accuracies for both absolute and relative position and velocity. Another key task for the RPO processor is maneuver planning. This includes automation to plan maneuvers to achieve a desired formation configuration or trajectory (including docking), as well as automation to safely react to potentially dangerous situations. This will allow each spacecraft to autonomously plan fuel-efficient maneuvers to achieve a desired trajectory as well as compute adjustment maneuvers to correct for thrusting errors. This paper discusses results from a trade study that has been conducted to examine maneuver targeting algorithms required on-board the spacecraft. Ground software will also work in conjunction with the on-board software to validate and approve maneuvers as necessary.

Griesbach, J.; Westphal, J. J.; Roscoe, C.; Hawes, D. R.; Carrico, J. P.

2013-09-01

235

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

236

5-(N,N-Dimethyl)-amiloride to discriminate the Unidirectional electrolyte transports in rat small intestine and proximal colon in vivo.  

PubMed

The effect of dimethyl-amiloride (DMA), a selective Na+/H+ exchange blocker, was studied on electrolyte net fluxes and unidirectional fluxes of Na and Cl at four levels of rat intestine in vivo in basal conditions. DMA was applied intraluminally at concentrations of 10(-4) and 10(-3) M in the model of ligated loops prepared from duodenum, proximal jejunum, distal ileum and ascending colon in fasted Sprague Dawley rats. Two iso-osmotic test solutions were used: (1) hypo-ionic: Na+ 80 mM and (2) iso-ionic: Na+ 148 mM, pH 8.2. 22Na was placed in the loop and 36Cl was given by intravenous route at the beginning of the experiment. Na+/H+ was calculated by two different means, one was based on pH variation following amiloride inhibition of Na influx, the other on the calculation of the passive Na transport. The quantitative evaluation shows that Na/H exchange largely contributes to the electroneutral absorption and luminal pH regulation. The exchanger activity decreases from duodenum, jejunum, ileum and colon where it is completed by K/H exchange to assure low colon luminal pH. PMID:11253816

Grishina, O; Volant, K; Pansu, D; Descroix-Vagne, M

1998-01-01

237

A strongly convergent proximal bundle method for convex ...  

E-print Network

Dec 6, 2013 ... new iterate xk+1 of a proximal bundle method depends on ˆxl and fM .... Consider a hydro-thermal system composed of m power plants (hydro-valleys, thermal or nuclear-plants), ... Therefore, for the unit-commitment problem the aim is ...... W. van Ackooij, Decomposition approaches for block-structured ...

2013-12-06

238

Proximity to coast is linked to climate change belief.  

PubMed

Psychologists have examined the many psychological barriers to both climate change belief and concern. One barrier is the belief that climate change is too uncertain, and likely to happen in distant places and times, to people unlike oneself. Related to this perceived psychological distance of climate change, studies have shown that direct experience of the effects of climate change increases climate change concern. The present study examined the relationship between physical proximity to the coastline and climate change belief, as proximity may be related to experiencing or anticipating the effects of climate change such as sea-level rise. We show, in a national probability sample of 5,815 New Zealanders, that people living in closer proximity to the shoreline expressed greater belief that climate change is real and greater support for government regulation of carbon emissions. This proximity effect held when adjusting for height above sea level and regional poverty. The model also included individual differences in respondents' sex, age, education, political orientation, and wealth. The results indicate that physical place plays a role in the psychological acceptance of climate change, perhaps because the effects of climate change become more concrete and local. PMID:25047568

Milfont, Taciano L; Evans, Laurel; Sibley, Chris G; Ries, Jan; Cunningham, Andrew

2014-01-01

239

A Proximal Point Algorithm with ?-Divergence to Quasiconvex ...  

E-print Network

We use the proximal point method with the ?-divergence given by ?(t) = t?log t?1 for the ... a sequence {xk} by the iterative scheme: start with an inicial point x0 ? IRn and solve ... interior of the nonnegative orthant of IRn, i.e., the algorithm (1.3) will ..... [2] Ashton, D. J. and Atkins, D. R. (1979), Multicriteria programming for ...

2006-07-19

240

Vascular Anatomy of the Proximal Fibula from Embalmed Cadaveric Dissection  

Microsoft Academic Search

Objectives: To study the vascular pattern of proximal fibula with use of embalmed cadaveric specimens. Material and Method: The present study was done on 33 lower extremities from 19 embalmed human, adult cadavers. The average ages of the cadavers were 68.6 years (range from 36 to 98 years), 11 females and 8 males. The size and site of vessels around

Tala Thammaroj; Surut Jianmongkol; Kimaporn Kamanarong

241

A Practical Relay Attack on ISO 14443 Proximity Cards  

E-print Network

to a distance of 50 m. Simply relaying information between the card and reader over a longer distance does-powered reader. Contactless smart cards operate at 13.56 MHz and are further divided into proximity (ISO 14443 [4 with Modified Miller coding (106 kbit/s) in reader to card communication. The width of the modulation pulses

Hancke, Gerhard

242

Integrated nonlinear optimal control of spacecraft in proximity operations  

Microsoft Academic Search

This article proposes an integrated optimal control strategy for a servicing spacecraft in proximity operations on a target in space. The relative position vector between the servicing spacecraft and the target is required to direct towards the docking port of the target while the attitude of the two bodies must be synchronised without exciting large flexible vibrations. The control of

Ming Xin; Hejia Pan

2010-01-01

243

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

244

Radar proximity fuzing and the Cold War paradigm  

Microsoft Academic Search

This paper covers an overview of the history of radar proximity fuze design, with an emphasis on previous design approaches of radar fuzing used for strategic and tactical nuclear missiles, and how the Cold War paradigm drove the requirements. Also covered is a discussion of the how the Cold War \\

Michael A. Kolodny

2011-01-01

245

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

246

Energy Efficient Proximity Alert on Android Muhammed Fatih Bulut  

E-print Network

by high- precision proximity alert is novel social networking ap- plications. Although some smartphone; smartphones; energy-efficiency I. INTRODUCTION In the last couple of years, the number of smartphone users access to web, and supreme portability, smartphones position them- selves as an alternative to personal

Demirbas, Murat

247

Efficient Private Proximity Testing with GSM Location Sketches  

E-print Network

]. It also has potential for building social networks, since sharing proximity fre- quently over time the proliferation of smart- phones and online social networking sites. Equipped with GPS receivers and/or base station triangulation, most smartphones are able to pinpoint their geographic coordi- nates. As a result

Minnesota, University of

248

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

249

Proximate and Ultimate Mechanisms of Spiny Lobster Gregariousness  

E-print Network

Abstract Proximate and Ultimate Mechanisms of Spiny Lobster Gregariousness Ken Sercy and Michael show clear differences in spiny lobster gregariousness. Panulirus argus is usually found sharing variation in lobster distribution and fitness. Spiny lobsters are a convenient model system for studying

Childress, Michael J.

250

High aspect ratio patterning with a proximity ultraviolet source  

Microsoft Academic Search

A considerably less expensive option to synchrotron exposures of thick film photoresists is to use a proximity UV exposure tool. The use of UV radiation, however, is potentially limited by aerial image degradation as the image propagates through the thick photoresist layer. In addition to diffraction, run-out from uncollimated light or absorption in the resist easily dominate the aerial image

Paul M. Dentinger; Karen L. Krafcik; Kelby L. Simison; Richard P. Janek; John Hachman

2002-01-01

251

Proximity to Coast Is Linked to Climate Change Belief  

PubMed Central

Psychologists have examined the many psychological barriers to both climate change belief and concern. One barrier is the belief that climate change is too uncertain, and likely to happen in distant places and times, to people unlike oneself. Related to this perceived psychological distance of climate change, studies have shown that direct experience of the effects of climate change increases climate change concern. The present study examined the relationship between physical proximity to the coastline and climate change belief, as proximity may be related to experiencing or anticipating the effects of climate change such as sea-level rise. We show, in a national probability sample of 5,815 New Zealanders, that people living in closer proximity to the shoreline expressed greater belief that climate change is real and greater support for government regulation of carbon emissions. This proximity effect held when adjusting for height above sea level and regional poverty. The model also included individual differences in respondents' sex, age, education, political orientation, and wealth. The results indicate that physical place plays a role in the psychological acceptance of climate change, perhaps because the effects of climate change become more concrete and local. PMID:25047568

Milfont, Taciano L.; Evans, Laurel; Sibley, Chris G.; Ries, Jan; Cunningham, Andrew

2014-01-01

252

Proximate Causes of Two Types of AB Questions  

E-print Network

Nervous system has fast response but shorter duration Endocrine system has slower response but longer Proximate Factors Hormones Nervous system Genes Environment Parasites/symbionts #12;3 Hormones & Behavior Hormones are chemical signaling molecules that travel through blood (or other fluid) Come from: Endocrine

Brown, Christopher A.

253

NOAA Technical Report NMFS 74 Proximate Composition and Fatty  

E-print Network

NOAA Technical Report NMFS 74 Proximate Composition and Fatty Acid and Cholesterol Content of 22.S. Department of Commerce May 1989 #12;NOAA TECHNICAL REPORT NMFS _ The major responsibilities of the National. It collects, analyzes, and publishes statistics on various phases of the industry. The NOAA Technical Report

254

Performance characteristics of proximity focused ultraviolet image converters  

NASA Technical Reports Server (NTRS)

Performance characteristics of Bendix type BX 8025-4522 proximity focused image tubes for UV to visible light conversion are presented. Quantum efficiency, resolution, background, geometric distortion, and environmental test results are discussed. The converters use magnesium fluoride input windows with Cs-Te photocathodes and P-11 phosphors on fiber optic output windows.

Williams, J. T.; Feibelman, W. A.

1973-01-01

255

Down the Rabbit Hole: Robust Proximity Search in Sublinear Space  

E-print Network

. ...... Down the Rabbit Hole: Robust Proximity Search in Sublinear Space Sariel Har-Peled1 Nirman Kumar1 1UIUC, Illinois, USA November 12, 2011 Har-Peled and Kumar (UIUC) Down the Rabbit Hole: Robust in sublinear space Sariel Har-Peled and Nirman Kumar UIUC November 12, 2011 Har-Peled and Kumar (UIUC) Down

Har-Peled, Sariel

256

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

257

Nature of Proximate Mechanisms Underlying Primate Social Systems: Simplicity and  

E-print Network

Nature of Proximate Mechanisms Underlying Primate Social Systems: Simplicity and Redundancy SALLY P. MENDOZA, DEEANN M. REEDER, AND WILLIAM A. MASON Given the complexity of primate so- cial systems of social groups that primates form and maintain are characteristic of a given species.1 It is also clear

Reeder, DeeAnn M.

258

Proximal-Gradient Algorithms For Tracking Cascades Over Social Networks  

E-print Network

reasons e.g., when social media advertisers select a small set of initiators so that an online campaignProximal-Gradient Algorithms For Tracking Cascades Over Social Networks Brian Baingana, Student weights. Assuming a slowly time-varying topology and leveraging the sparse connectivity inherent to social

Giannakis, Georgios

259

Projection-proximal methods for general variational inequalities  

Microsoft Academic Search

In this paper, we consider and analyze some new projection-proximal methods for solving general variational inequalities. The modified methods converge for pseudomonotone operators which is a weaker condition than monotonicity. The proposed methods include several new and known methods as special cases. Our results can be considered as a novel and important extension of the previously known results. Since the

Muhammad Aslam Noor

2006-01-01

260

Proximal projection methods for variational inequalities and Cesáro averaged approximations  

Microsoft Academic Search

In this paper, we prove convergence and stability of Cesáro averages generated by the proximal projection method applied to nonlinear equations and variational inequalities in uniformly convex and uniformly smooth Banach spaces. We first consider the stability of the approximations with respect to perturbations of the operator and constraint sets. Weak convergence of Cesáro averages is shown to hold with

Ya. I. Alber

2002-01-01

261

Connectivity of Cognitive Radio Networks: Proximity vs. Opportunity  

E-print Network

Connectivity of Cognitive Radio Networks: Proximity vs. Opportunity Wei Ren and Qing Zhao Dept the connectivity of large-scale ad hoc cognitive radio networks, where secondary users exploit channels temporarily General Terms Algorithms, Design, Theory Keywords Cognitive radio, connectivity, continuum percolation 1

Islam, M. Saif

262

Scaffolding Critical Thinking in the Zone of Proximal Development  

ERIC Educational Resources Information Center

This paper explores student experiences of learning to think critically. Twenty-six zoology undergraduates took part in the study for three years of their degree at the University of Otago, New Zealand. Vygotsky's developmental model of the Zone of Proximal Development (ZPD) provided a framework as we examined how critical thinking was developed.…

Wass, Rob; Harland, Tony; Mercer, Alison

2011-01-01

263

Rendezvous and Proximity Operations of the Space Shuttle  

NASA Technical Reports Server (NTRS)

Space Shuttle rendezvous missions present unique challenges that were not fully recognized when the Shuttle was designed. Rendezvous targets could be passive (i.e., no lights or transponders), and not designed to facilitate Shuttle rendezvous, proximity operations, and retrieval. Shuttle reaction control system jet plume impingement on target spacecraft presented induced dynamics, structural loading, and contamination concerns. These issues, along with limited reaction control system propellant in the Shuttle nose, drove a change from the legacy Gemini/Apollo coelliptic profile to a stable orbit profile, and the development of new proximity operations techniques. Multiple scientific and on-orbit servicing missions, and crew exchange, assembly and replenishment flights to Mir and to the International Space Station drove further profile and piloting technique changes. These changes included new proximity operations, relative navigation sensors, and new computer generated piloting cues. However, the Shuttle's baseline rendezvous navigation system has not required modification to place the Shuttle at the proximity operations initiation point for all rendezvous missions flown.

Goodman, John L.

2005-01-01

264

Proximity soundings of thundersnow in the central United States  

Microsoft Academic Search

Proximity balloon soundings for snow events with lightning and thunder during the period 1961 through 1990 reveal a less statically stable environment than similar nonthundering snow events. When thundersnow is present, a less stable environment (and in some cases subsequent upright convection) is found aloft in all of the thundering cases examined here; all of the events feature their most

Angela M. Oravetz; David Gaede; Evan Bookbinder; Anthony R. Lupo; Christopher J. Melick; Larry L. Smith; Rashida Thomas; Rachel Redburn; Brian P. Pettegrew; Amy E. Becker

2006-01-01

265

Behaviour Detection Using Bluetooth Proximity Muhammad Awais Azam 1, 2  

E-print Network

.tokarchuk@elec.qmul.ac.uk Abstract The abundance of Bluetooth enabled devices used in daily life has created new ways to analyze. Bluetooth radios are frequently incorporated in to the mobile devices [9]. Nearly 2.4 billion Bluetooth place in their proximity. The large penetration of Bluetooth enabled devices enables the use

Tokarchuk, Laurissa

266

Proximal Versus Distal Gastric Carcinoma—What Are the Differences?  

Microsoft Academic Search

Background: The incidence of proximal gastric third carcinoma (PGC) has been rising in recent years. Classification and surgical therapy remain controversial. Methods: Between May 1986 and October 1997, 532 patients were operated for primary gastric carcinoma. All patient data were analyzed retrospectively comparing findings in patients with PGC and those with distal gastric carcinoma (DGC). Results: Two hundred fifty patients

Pompiliu Piso; Uwe Werner; Hauke Lang; Petrit Mirena; Jürgen Klempnauer

2000-01-01

267

Text Retrieval by Using k-word Proximity Search  

Microsoft Academic Search

When we search from a huge amount of documents, we often specify several keywords and use conjunctive queries to narrow the result of the search. Though the searched documents contain all keywords, positions of the keywords are usually not considered. As the result, the search result contains some meaningless documents. It is therefore effective to rank documents according to proximity

Kunihiko Sadakane; Hiroshi Imai

1999-01-01

268

Generalized Proximal Method for Efficient Solutions in Vector Optimization  

Microsoft Academic Search

This article is devoted to developing the generalized proximal algorithm of finding efficient solutions to the vector optimization problem for a mapping from a uniformly convex and uniformly smooth Banach space to a real Banach space with respect to the partial order induced by a pointed closed convex cone. In contrast to most published literature on this subject, our algorithm

T. D. Chuong

2011-01-01

269

Proximity Connector for Two-Dimensional Electromagnetic Wave Communication  

E-print Network

proposed a new physical layer of communication named "Two-Dimensional Communication (TDC)." TDC and power transmission connector that works anywhere on the TDC sheet without presice positioning. Moreover, it works as a proximity connector requiring no electrical contacts to the TDC sheet. If the surfaces

Shinoda, Hiroyuki

270

Dynamic Studies of Proximity Coupled Josephson Junction Arrays  

Microsoft Academic Search

The results of dynamic studies of proximity coupled Josephson junction arrays are presented. Five different array sizes (1 x 1, 4 x 4, 9 x 9, 24 x 24, and 1000 x 1000) have been fabricated by patterning square niobium crosses on top of a uniform gold film. For the small arrays (1 x 1, 4 x 4, 9 x

Yau-Chee Hui

1993-01-01

271

Classification on Proximity Data with LP-Machines  

Microsoft Academic Search

We provide a new linear program to deal with clas- sification of data in the case of functions written in terms of pairwise proximities. This allows to avoid the problems inherent in using feature spaces with in- definite metric in Support Vector Machines, since the notion of a margin is purely needed in input space where the classification actually occurs.

Thore Graepel; Ralf Herbrich; Bernhard Scholkopf; Alex Smola; Peter Bartlett; Klaus-Robert Muller; Klaus Obermayer; Robert Williamson

272

Proximal humeral nonunion treated with an intramedullary tantalum cylinder.  

PubMed

Nonunion is uncommon after proximal humerus fracture surgery. There is no agreement about preferred method of treatment. Traditional approaches have included laterally based locking plates, autogenous grafting, and endosteal support to provide improved biomechanical stability. Open reduction and internal fixation (ORIF) of proximal humeral nonunion has been performed with various methods, including blade plates and bone grafting, as well as intramedullary support with autologous or allogenic grafts. Both malunion and nonunion have occurred after ORIF with locking plates. Endosteal support in the form of a fibular allograft incorporated into the locking plate construct can increase mechanical stability in selected cases. An ideal implant for proximal humeral nonunion provides medial column mechanical support and osteoconductive and osteoinductive properties. Porous intramedullary tantalum metal may play a role in nonunion surgery as an alternative to fibular allograft because of its versatility of use and salutary biological effects. It offers many material advantages for use in nonunion surgery. Tantalum is extensively porous (75%-80%), has a stiffness close to that of native bone, and offers the possibility of being a carrier for osteoinductive materials. It may also be suitable for patients who refuse allograft material. This article describes a 65-year-old woman with recalcitrant proximal humeral nonunion who was successfully treated with revision ORIF with intramedullary tantalum cylinder augmentation with a lateral-based locking plate and autogenous cancellous bone grafting. At 5-year follow-up, she had excellent motion and clinical and radiographic union. PMID:24579230

Georgiadis, Gregory M; Georgiadis, Andrew G

2013-12-01

273

Street marketing: how proximity and context drive coupon redemption  

Microsoft Academic Search

Purpose – In 2009, US coupons set a new record of 367 billion coupons distributed. Yet, while coupon distribution is on the rise, redemption rates remain below 1 percent. This paper aims to show how recognizing context variables, such as proximity, weather, part of town and financial incentives interplay to determine a coupon campaign's success. Design\\/methodology\\/approach – The paper reports

Sarah Spiekermann; Matthias Rothensee; Michael Klafft

2011-01-01

274

NETSCAL: A Network Scaling Algorithm for Nonsymmetric Proximity Data.  

ERIC Educational Resources Information Center

A Monte Carlo simulation and applications to eight sets of proximity data are presented to support the practical utility of a network scaling algorithm (NETSCAL)--NETwork SCALing. The algorithm determines which vertices within a network are directly connected by an arc and estimates the length of each arc. (TJH)

Hutchinson, J. Wesley

1989-01-01

275

Modelling Primate Social Order: Ultimate and Proximate Explanations  

E-print Network

Modelling Primate Social Order: Ultimate and Proximate Explanations Hagen Lehmann and Joanna J.Lehmann@bath.ac.uk, J.J.Bryson@bath.ac.uk Abstract. For many species of primates, arguably including humans, social be understanding the bases of our social interaction. For many primate species social be- haviour has been

Bryson, Joanna J.

276

Double Onlay Preputial Flap for Proximal Hypospadias Repair  

Microsoft Academic Search

PurposeWe describe a new technique for primary repair of proximal hypospadias. The double onlay preputial flap combines the principles of onlay urethroplasty and the double face preputial flap, namely preservation of the urethral plate and use of a total preputial flap.

Ricardo Gonzalez; Craig Smith; Enrique D. Denes

1996-01-01

277

Interior Proximal Algorithm with Variable Metric for Second-Order ...  

E-print Network

Note that the matrix Mk defines the shape of the level curves of the variable metric ...... towards a particular class; for instance, in the case of medical diagnosis one ..... The Variable Metric Proximal Point Algorithm: Theory and Application, Ph.D.

2009-06-05

278

A proximal point algorithm for DC functions on Hadamard manifolds  

E-print Network

It is well known that the class of Proximal Point Algorithm (PPA) is one of the ... techniques that fit in Euclidean spaces is natural and nontrivial. Actually, in recent ... manifolds, it is isomorphic to Rm. If M is endowed with a Riemannian metric g,.

2015-03-13

279

Chemotherapy Is More Active against Proximal than Distal Gastric Carcinoma  

Microsoft Academic Search

Objective: Patients with localized proximal gastric carcinoma (PGC) have a poorer outcome than those with distal gastric carcinoma (DGC) following curative resection. However, it remains uncertain whether the location of the primary tumor influences the effect of chemotherapy in advanced gastric carcinoma. Methods: We assessed 270 eligible patients with unresectable, advanced gastric carcinoma who had received first-line chemotherapy between 1989

Katsuhiko Higuchi; Wasaburo Koizumi; Satoshi Tanabe; Katsunori Saigenji; Jaffer A. Ajani

2004-01-01

280

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

281

De novo partial trisomy 15q (proximal type).  

PubMed Central

This report describes a retarded girl with strabismus, high arched palate, antimongoloid slant, low set ears, hearing loss, micrognathia, short neck, and an anteriorly displaced anus. She was found to have a de novo partial trisomy of the proximal part of the long arm of chromosome 15. Images PMID:2966860

Herweijer, T J; Oorthuys, J W; Leschot, N J

1988-01-01

282

Proximal Tumors Are Associated with Greater Mortality in Colon Cancer  

PubMed Central

ABSTRACT BACKGROUND Colon cancer is the third leading cause of death from cancer in the United States. Recent studies report on increasing proportions of proximal cancers. The etiology behind this epidemiological trend is unclear, and its implication on survival outcomes is unknown. Further analysis of the impact of anatomic site of disease among a large multiethnic population will help facilitate research and education to improve colon cancer screening and treatment. OBJECTIVE To investigate the association between proximal tumor location and survival in patients with colon cancer. DESIGN AND PARTICIPANTS A large retrospective cohort study in the US utilizing the Surveillance, Epidemiology, and End Results (SEER) cancer registry analyzed survival outcomes of patients with colon cancer. Multivariable logistic regression analyses investigated sex-specific, race/ethnicity-specific, and anatomic site-specific disparities in survival. MAIN MEASURES Five-year survival outcomes from colon cancer. RESULTS Our study demonstrated significant disparities in survival by sex, race/ethnicity, and anatomic site. Across all time periods and among most cohorts, patients with proximal cancers had significantly worse survival outcomes. When compared to distal cancers, patients with proximal cancers were 13% less likely to survive 5 years (OR 0.87; 95% CI, 0.82–0.91). When compared to non-Hispanic whites, blacks were 30% less likely to survive 5 years (OR 0.70; 95% CI, 0.68–0.73). Stage-specific multivariable regression analysis of localized cancers demonstrated similar findings. CONCLUSIONS Significant race-specific, sex-specific, and anatomic site-specific disparities in colon cancer survival exist. Proximal cancers are associated with worse survival odds. These disparities may reflect differences in the genotype and phenotype of colon cancer among these groups. A modified risk assessment tool that incorporates these variations may be more effective in the early detection and treatment of colon cancer. PMID:20652758

2010-01-01

283

Indices of risk assessment of fracture of the proximal humerus  

PubMed Central

Summary Osteoporotic fractures are now a social problem for incidence and costs. Fractures of the proximal humerus events are frequent and constantly increasing. It is estimated that they are 20% of all osteoporotic fractures. Bone densitometry in most cases underestimates the real humeral bone density. There is little information about osteoporotic changes in the proximal humerus and their association with the cortical thickness of the humeral shaft. The ratio between the thickness of the cortical and the total diameter of the humeral diaphysis is the cortical index. Fracture risk limit value is 0.231. Convinced of the need to quantify in a reproducible way the real local humerus bone density, we performed a comparative evaluation of bone density of the humerus and femur in patients admitted to our clinic for fractures of the humerus and femur. We evaluated 28 women treated surgically for a fragility fracture of the proximal humerus or femur neck in 2010. All cortical index obtained were lower than the limit for fracture risk set at 0.231, so the IC was more predictive of neck medial fractures of the femur than had DEXA and the U.S. The information about the cortical index may provide a simple way of determining the bone quality of the proximal humerus and of facilitating decision-making in the surgical treatment of patients with fractures of the humerus. So we want to emphasize the importance of therapy for osteoporosis even in patients with fractures of the proximal humerus, which often have not critical densitometric values of femur or column, but they are at risk of new fractures. PMID:22783334

Giannotti, Stefano; Bottai, Vanna; Dell’osso, Giacomo; Donati, Daniela; Bugelli, Giulia; De Paola, Gaia; Guido, Giulio

2012-01-01

284

Acute renal proximal tubule alterations during induced metabolic crises in a mouse model of glutaric aciduria type 1.  

PubMed

The metabolic disorder glutaric aciduria type 1 (GA1) is caused by deficiency of the mitochondrial glutaryl-CoA dehydrogenase (GCDH), leading to accumulation of the pathologic metabolites glutaric acid (GA) and 3-hydroxyglutaric acid (3OHGA) in blood, urine and tissues. Affected patients are prone to metabolic crises developing during catabolic conditions, with an irreversible destruction of striatal neurons and a subsequent dystonic-dyskinetic movement disorder. The pathogenetic mechanisms mediated by GA and 3OHGA have not been fully characterized. Recently, we have shown that GA and 3OHGA are translocated through membranes via sodium-dependent dicarboxylate cotransporter (NaC) 3, and organic anion transporters (OATs) 1 and 4. Here, we show that induced metabolic crises in Gcdh(-/-) mice lead to an altered renal expression pattern of NaC3 and OATs, and the subsequent intracellular GA and 3OHGA accumulation. Furthermore, OAT1 transporters are mislocalized to the apical membrane during metabolic crises accompanied by a pronounced thinning of proximal tubule brush border membranes. Moreover, mitochondrial swelling and increased excretion of low molecular weight proteins indicate functional tubulopathy. As the data clearly demonstrate renal proximal tubule alterations in this GA1 mouse model during induced metabolic crises, we propose careful evaluation of renal function in GA1 patients, particularly during acute crises. Further studies are needed to investigate if these findings can be confirmed in humans, especially in the long-term outcome of affected patients. PMID:23623985

Thies, Bastian; Meyer-Schwesinger, Catherine; Lamp, Jessica; Schweizer, Michaela; Koeller, David M; Ullrich, Kurt; Braulke, Thomas; Mühlhausen, Chris

2013-10-01

285

The Utility of Proximal-Accretion Stratigraphy in Lateral Moraines  

NASA Astrophysics Data System (ADS)

Lateral-moraine stratigraphy is a valuable tool that can be used to constrain the timing and magnitude of alpine glacier fluctuations. Numerous lateral moraines, conventionally thought to have been constructed during the Little Ice Age (LIA), have been shown to be composite landforms that contain multiple till layers deposited by successively larger glacier advances. Organic matter and/or tephra sandwiched between the till layers constrain times of advance and retreat; wood fragments within till may provide the age of the till. Observation of contemporary lateral moraines has lead to the recognition of two means of lateral moraine construction: (1) accretion of tills onto the distal flank of the pre-existing lateral moraine, and (2) accretion or plastering of tills onto the proximal flank of the pre-existing moraine. In composite lateral moraines, distal and proximal accretion result in paleosurfaces that trend parallel to the current distal and proximal slope, respectively. Published work using lateral-moraine stratigraphy, for example at Bugaboo and Stutfield glaciers in the Canadian Rockies, has used evidence only from distal-accretion moraines. However, proximal-accretion moraines that provide chronological information have been found at Nisqually Glacier on Mount Rainier in Washington State, USA, and Columbia Glacier, an outlet of the Columbia Icefield in the Canadian Rockies. A gully cut into the left-lateral moraine at Nisqually Glacier exposes a sandy seam, with associated wood fragments, that runs parallel to the proximal moraine flank for ~20 m. Wood collected from different elevations along the seam have radiocarbon ages of 1715±15, 1700±15, and 1670±50 14C yr BP, indicating that the seam is similar in age along its extent and likely marks a paleosurface separating older till below and till of the First Millennium advance above. At Columbia Glacier, some till exposures in the prominent right-lateral moraine show a fissility dipping variably 40 to 50° toward the valley axis; this orientation is semi-parallel to the proximal flank of the moraine, which however is steeper due to ongoing erosion. Five wood fragments encased in the till over a broad area of the flank, and exposed by gullying, have ages ranging from 1920±70 to 2340±70 14C yr BP. This suggests that (1) most of what appears to be a LIA moraine was deposited in earlier Neoglacial time, and (2) that the glacier was nearly as extensive ca. 2400-1900 ka as it was during the LIA.

Samolczyk, M. A.; Osborn, G.

2010-12-01

286

Proximate and landscape factors influence grassland bird distributions.  

PubMed

Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the Sheyenne National Grassland in North Dakota, USA. The Grassland contains a diverse array of grassland and woodland habitats. We surveyed breeding birds on 2015 100 m long transect segments during 2002 and 2003. We modeled the occurrence of 19 species in relation to habitat features (percentages of grassland, woodland, shrubland, and wetland) within each 100-m segment and to tree cover within 200-1600 m of the segment. We used information-theoretic statistical methods to compare models and variables. At the proximate scales, tree cover was the most important variable, having negative influences on 13 species and positive influences on two species. In a comparison of multiple scales, models with only proximate variables were adequate for some species, but models combining proximate with landscape information were best for 17 of 19 species. Landscape-only models were rarely competitive. Combined models at the largest scales (800-1600 m) were best for 12 of 19 species. Seven species had best models including 1600-m landscapes plus proximate factors in at least one year. These were Wilson's Phalarope (Phalaropus tricolor), Sedge Wren (Cistothorus platensis), Field Sparrow (Spizella pusilla), Grasshopper Sparrow (Ammodramus savannarum), Bobolink (Dolychonix oryzivorus), Red-winged Blackbird (Agelaius phoeniceus), and Brown-headed Cowbird (Molothrus ater). These seven are small-bodied species; thus larger-bodied species do not necessarily respond most to the largest landscapes. Our findings suggest that birds respond to habitat features at a variety of scales. Models with only landscape-scale tree cover were rarely competitive, indicating that broad-scale modeling alone, such as that based solely on remotely sensed data, is likely to be inadequate in explaining species distributions. PMID:16827003

Cunningham, Mary Ann; Johnson, Douglas H

2006-06-01

287

Na+\\/H+ exchange activity and NHE-3 expression in renal tubules from the spontaneously hypertensive rat  

Microsoft Academic Search

Na+\\/H+ exchange activity and NHE-3 expression in renal tubules from the spontaneously hypertensive rat.BackgroundThe NHE-3 isoform of the Na+\\/H+ antiporter, in the apical membrane of renal proximal tubule, is responsible for the bulk transport of Na+ and fluid reabsorption. Studies have reported that apical NHE-3 translocates to internal pools, thereby facilitating natriuresis when blood pressure increases abruptly.MethodsThe present study examined

Michael S Lapointe; Chhinder Sodhi; Atul Sahai; Daniel Batlle

2002-01-01

288

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 PMID:8134357

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

1994-01-01

289

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

290

A critical assessment of proximal macrotexturing on cemented femoral components.  

PubMed

We analyzed the cement-metal interface of 3 different types of femoral components that had proximal macrotexturing after in vitro insertion and after fatigue testing designed to produce debonding and micromotion. These components were compared with clinical retrieval specimens. The cement did not flow into the macrotexturing; rather, hollow, brittle volcanoes or calderas were formed. These fragile protrusions of cement become worn down or abraded by debonded components. This abrasion of cement may contribute to the early and aggressive osteolysis seen in some of these early failures with proximal macrotextured components. The formation of these volcanos and calderas can be aborted by placing bone-cement onto the macrotexturing before stem insertion. This simple technique allows the macrotexturing to be filled with cement. PMID:11742450

Duffy, G P; Muratoglu, O K; Biggs, S A; Larson, S L; Lozynsky, A J; Harris, W H

2001-12-01

291

STRaND-2: Visual inspection, proximity operations & nanosatellite docking  

NASA Astrophysics Data System (ADS)

The Surrey Training Research and Nanosatellite Demonstrator (STRaND) programme has been success in identifying and creating a leading low-cost nanosatellite programme with advanced attitude and orbit control system (AOCS) and experimental computing platforms based on smart-phone technologies. The next demonstration capabilities, that provide a challenging mission to the existing STRaND platform, is to perform visual inspection, proximity operations and nanosatellite docking. Visual inspection is to be performed using a COTS LIDAR system to estimate range and pose under 100 m. Proximity operations are controlled using a comprehensive guidance, navigation and control (GNC) loop in a polar form of the Hills Clohessy Wiltshire (HCW) frame including J2 perturbations. And finally, nanosatellite docking is performed at under 30 cm using a series of tuned magnetic coils. This paper will document the initial experiments and calculations used to qualify LIDAR components, size the mission thrust and tank requirements, and air cushion table demonstrations of the docking mechanism.

Bridges, C. P.; Taylor, B.; Horri, N.; Underwood, C. I.; Kenyon, S.; Barrera-Ars, J.; Pryce, L.; Bird, R.

292

Proximity effect enhancement induced by a superconducting anti-dot  

NASA Astrophysics Data System (ADS)

In this work, we study the proximity and pinning effects of a rectangular superconducting anti-dot on the magnetization curve of a mesoscopic sample. We solve the nonlinear time-dependent Ginzburg-Landau equations for a superconducting rectangle in the presence of a magnetic field applied perpendicular to its surface. The pinning effects are determined by the number of vortices into the anti-dot. We calculate the order parameter, vorticity, magnetization and critical fields as a function of the external magnetic field. We found that the size and nature of the anti-dot strongly affect the magnetization of the sample. The results are discussed in framework of pinning and proximity effects in mesoscopic systems.

Higuera, Sindy J.; Joya, Miryam R.; Barba-Ortega, J.

2014-12-01

293

Proximity nanovalve with large phase-tunable thermal conductance  

SciTech Connect

We propose a phase-controlled heat-flux quantum valve based on the proximity effect driven by a superconducting quantum interference proximity transistor (SQUIPT). Its operation relies on the phase-dependent quasiparticle density of states in the Josephson weak-link of the SQUIPT which controls thermal transport across the device. In a realistic Al/Cu-based setup the structure can provide efficient control of thermal current inducing temperature swings exceeding ?100?mK, and flux-to-temperature transfer coefficients up to ?500?mK/?{sub 0} below 100?mK. The nanovalve performances improve by lowering the bath temperature, making the proposed structure a promising building-block for the implementation of coherent caloritronic devices operating below 1?K.

Strambini, E., E-mail: e.strambini@sns.it; Giazotto, F., E-mail: f.giazotto@sns.it [NEST Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Bergeret, F. S., E-mail: sebastian-bergeret@ehu.es [Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Donostia International Physics Center (DIPC), Manuel de Lardizabal 5, E-20018 San Sebastián (Spain); Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg (Germany)

2014-08-25

294

Rendezvous and Proximity Operations of the Space Shuttle  

NASA Technical Reports Server (NTRS)

Space Shuttle rendezous missions presented unique challenges that were not fully recognized when the Shuttle was designed. Rendezvous targets could be passive (i.e., no lights or transponders), and not designed to facilitate Shuttle rendezvous, proximity operations and retrieval. Shuttle reaction control system jet plume impingement on target spacecraft presented induced dynamics, structural loading and contamination concerns. These issues, along with limited forward reaction control system propellant, drove a change from the Gemimi/Apollo coelliptic profile heritage to a stable orbit profile, and the development of new proximity operations techniques. Multiple scientific and on-orbit servicing missions and crew exchange, assembly and replinishment flights to Mir and to the International Space Station drove further profile and piloting technique changes, including new relative navigation sensors and new computer generated piloting cues.

Goodman, John L.

2005-01-01

295

Locality of information obtained from proximity-electron-tunneling spectroscopy  

SciTech Connect

The locality of the information obtained by the technique of proximity-electron tunneling (PETS) is analyzed, with particular attention to the effects on the measured effective-phonon spectrum ..cap alpha../sup 2/F(..omega..) is disorder or impurities near the surface of the superconductor electrode. As in conventional tunnel junctions it is determined that the (energy-dependent) electron mean free path determines the maximum depth of the superconductor of which the measured phonon spectrum is characterized. An averaging length L(E) is defined and found to be typically larger in proximity junctions than in conventional junctions. This can make PET results inherently less susceptible than conventional results to surface disorder of the superconductor.

Arnold, G.B.; Wolf, E.L.

1982-02-01

296

Disproportionate Proximity to Environmental Health Hazards: Methods, Models, and Measurement  

PubMed Central

We sought to provide a historical overview of methods, models, and data used in the environmental justice (EJ) research literature to measure proximity to environmental hazards and potential exposure to their adverse health effects. We explored how the assessment of disproportionate proximity and exposure has evolved from comparing the prevalence of minority or low-income residents in geographic entities hosting pollution sources and discrete buffer zones to more refined techniques that use continuous distances, pollutant fate-and-transport models, and estimates of health risk from toxic exposure. We also reviewed analytical techniques used to determine the characteristics of people residing in areas potentially exposed to environmental hazards and emerging geostatistical techniques that are more appropriate for EJ analysis than conventional statistical methods. We concluded by providing several recommendations regarding future research and data needs for EJ assessment that would lead to more reliable results and policy solutions. PMID:21836113

Maantay, Juliana A.; Brender, Jean D.

2011-01-01

297

Partial claviculectomy after non-union of proximal clavicle fracture.  

PubMed

Non-union of a proximal clavicle fracture is rare. When it does occur, it poses a difficult problem causing severe pain and shoulder impairment that must be dealt with surgically. We report a 29-year-old woman who suffered a proximal clavicle fracture and received plate and screws fixation. Six months later, after constant pain and a diminished range of shoulder motion, she sought help at our clinic and was diagnosed with symptomatic non-union. Reconstruction with bone graft and interosseous sutures was performed in vain as pain persisted and follow-up radiograph showed no healing. A salvage procedure with partial claviculectomy was then carried out. The patient has been pain free after 3.5 years of follow-up, a full range of motion and is quite satisfied with the cosmetics. This outcome demonstrates that claviculectomy can be used successfully in a clinical situation where restoration of clavicular non-union fails. PMID:23542725

Teng, Hsiu-Gwo; Liu, Andy Li-Jen

2013-01-01

298

Financial markets and authoritative proximity in personal finance magazines.  

PubMed

This study investigates how mediated discourse about finance developed in the USA in parallel to the shift from a corporate liberal political economic order to a neoliberal one. This is done by analyzing two personal finance magazines, Money and Kiplinger's, utilizing both critical discourse analysis and longitudinal quantitative content analysis (1947-2008). I find that at the core of this discursive environment lies the phenomenon of authoritative proximity, which positions the magazines as trusted advisors guiding the audience, a collection of individuals, towards financial autonomy through immersion in financial markets. Authoritative proximity is constituted by second person address forms, imperative mood and paratactic syntax - all elements whose salience rises over time. This discourse, which makes the abstract financial system increasingly more concrete and focused on the individual, is compatible with the emergence of a neoliberal political economy. PMID:23825270

Davidson, Roei

2012-12-11

299

Copper in silicon: Quantitative analysis of internal and proximity gettering  

SciTech Connect

The behavior of copper in the presence of a proximity gettering mechanism and a standard internal gettering mechanism in silicon was studied. He implantation-induced cavities in the near surface region were used as a proximity gettering mechanism and oxygen precipitates in the bulk of the material provided internal gettering sites. Moderate levels of copper contamination were introduced by ion implantation such that the copper was not supersaturated during the anneals, thus providing realistic copper contamination/gettering conditions. Copper concentrations at cavities and internal gettering sites were quantitatively measured after the annealings. In this manner, the gettering effectiveness of cavities was measured when in direct competition with internal gettering sites. The cavities were found to be the dominant gettering mechanism with only a small amount of copper gettered at the internal gettering sites. These results reveal the benefits of a segregation-type gettering mechanism for typical contamination conditions.

McHugo, S.A. [Lawrence Berkeley National Lab., CA (United States); Flink, C.; Weber, E.R. [Univ. of California, Berkeley, CA (United States)] [and others

1997-08-01

300

Space station proximity operations windows: Human factors design guidelines  

NASA Technical Reports Server (NTRS)

Proximity operations refers to all activities outside the Space Station which take place within a 1-km radius. Since there will be a large number of different operations involving manned and unmanned vehicles, single- and multiperson crews, automated and manually controlled flight, a wide variety of cargo, and construction/repair activities, accurate and continuous human monitoring of these operations from a specially designed control station on Space Station will be required. Total situational awareness will be required. This paper presents numerous human factors design guidelines and related background information for control windows which will support proximity operations. Separate sections deal with natural and artificial illumination geometry; all basic rendezvous vector approaches; window field-of-view requirements; window size; shape and placement criteria; window optical characteristics as they relate to human perception; maintenance and protection issues; and a comprehensive review of windows installed on U.S. and U.S.S.R. manned vehicles.

Haines, Richard F.

1987-01-01

301

Proximal symphalangism: Evidence of linkage to 17q  

SciTech Connect

Proximal symphalangism (PS; OMIM 185800) is an autosomal dominant disorder which is characterized by ankylosis of the proximal interphalangeal joints and an increased incidence of conductive deafness in some families. A large American kindred with PS was originally described by Cushing in 1916, segregating for this disorder in many generations. Several follow-up studies have confirmed the disorder in members of this kindred and have also suggested that conductive deafness is a pleiotropic effect of the mutant gene in this family. In an effort to localize the gene, we have studied 55 members of Cushing`s kindred with 85 microsatellite repeat polymorphisms spanning the human genome. Genetic linkage analysis with data for marker D17S809 gave significant evidence for linkage with Zmax=3.4 at recombination fraction {theta}=0.05.

Francomano, C.A.; Rubenstein, J.R.; Polymeropoulos, M.H. [National Center for Human Genome Research, Bethesda, MD (United States)] [and others

1994-09-01

302

Half-TV format MWIR sensor module incorporating proximity electronics  

NASA Astrophysics Data System (ADS)

The Osprey-E sensor module consists of an integrated detector-cooler assembly (IDCA) and custom proximity electronics mounted in a lightweight, ruggedized housing. Based on the half-TV format Osprey FPA, it implements recent improvement in SELEX Galileo's array hybridization technique. Ongoing tests have shown that performance is not significantly degraded after more than 5000 cooldown cycles. The FPA exploits SELEX Galileo's High Operating Temperature (HOT) HgCdTe (MCT) and is optimized for operation at 110K. Very low levels of defective pixels (<0.003%) have been achieved at this temperature. The proximity electronics are a new design that originates from SELEX Galileo's Centre of Excellence in Infrared Detectors. The electronics provide all the necessary supplies and signals for detector operation and digitize the detector output into 14-bit digital video. The sensor has been developed to offer a very lightweight, rugged camera core particularly suited to airborne applications.

Ashcroft, A. P.; Richardson, L.; Harji, J.; Giuliano, F.

2012-06-01

303

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors  

NASA Technical Reports Server (NTRS)

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 also have 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 micrometers, 1450 times the mean-free path.

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

2009-01-01

304

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors  

NASA Technical Reports Server (NTRS)

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 also have 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 micrometers, 1450 times the mean-free path.

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

2010-01-01

305

Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors  

NASA Technical Reports Server (NTRS)

We have found experimentally that the critical current of a square superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T. 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 also have found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. The observed behavior has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. We have observed the proximity effect in these devices over extraordinarily long lengths exceeding 100 microns.

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

2009-01-01

306

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

307

Proximity effect in MgB2Permalloy hybrid system  

Microsoft Academic Search

Recently ferromagnet\\/superconductor systems have attracted a great attention due to their scientific interest and potential for the technological application. So far, most of the work has been done for Nb with ferromagnetic metals or high temperature oxide superconductors with magnetic oxides. In this presentation we will discuss the proximity effect in magnesium diboride (MgB2)\\/Py thin films, where the superconducting property

April O'Brien; Jiyeong Gu

2008-01-01

308

Elevated oxidized glutathione in cystinotic proximal tubular epithelial cells  

Microsoft Academic Search

Cystinosis, the most frequent cause of inborn Fanconi syndrome, is characterized by the lysosomal cystine accumulation, caused by mutations in the CTNS gene. To elucidate the pathogenesis of cystinosis, we cultured proximal tubular cells from urine of cystinotic patients (n=9) and healthy controls (n=9), followed by immortalization with human papilloma virus (HPV E6\\/E7). Obtained cell lines displayed basolateral polarization, alkaline

Martijn J. G. Wilmer; Adriana de Graaf-Hess; Henk J. Blom; Henry B. P. M. Dijkman; Leo A. Monnens; Lambertus P. van den Heuvel; Elena N. Levtchenko

2005-01-01

309

An implementable proximal point algorithmic framework for nuclear norm minimization  

Microsoft Academic Search

The nuclear norm minimization problem is to find a matrix with the minimum nuclear norm subject to linear and second order\\u000a cone constraints. Such a problem often arises from the convex relaxation of a rank minimization problem with noisy data, and\\u000a arises in many fields of engineering and science. In this paper, we study inexact proximal point algorithms in the

Yong-Jin Liu; Defeng Sun; Kim-Chuan Toh

310

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

311

Mesoscale nanoparticles selectively target the renal proximal tubule epithelium.  

PubMed

We synthesized "mesoscale" nanoparticles, approximately 400 nm in diameter, which unexpectedly localized selectively in renal proximal tubules and up to 7 times more efficiently in the kidney than other organs. Although nanoparticles typically localize in the liver and spleen, modulating their size and opsonization potential allowed for stable targeting of the kidneys through a new proposed uptake mechanism. Applying this kidney targeting strategy, we anticipate use in the treatment of renal disease and the study of renal physiology. PMID:25811353

Williams, Ryan M; Shah, Janki; Ng, Brandon D; Minton, Denise R; Gudas, Lorraine J; Park, Christopher Y; Heller, Daniel A

2015-04-01

312

Trabecular bone ontogeny in the human proximal femur  

Microsoft Academic Search

Ontogenetic changes in the human femur associated with the acquisition of bipedal locomotion, especially the development of the bicondylar angle, have been well documented. The purpose of this study is to quantify changes in the three-dimensional structure of trabecular bone in the human proximal femur in relation to changing functional and external loading patterns with age. High-resolution X-ray computed tomography

Timothy M. Ryan; Gail E. Krovitz

2006-01-01

313

Defective Proximal Tubule Lysosomal Acidification by Bence Jones Proteins  

Microsoft Academic Search

Proximal tubule handling of two human Bence Jones proteins (neutral and acidic BJP) was evaluated using protein A-gold labelling. After 30 min of acute light-chain infusion into 6 rats (alone or in combination with dinitrophenyl-aminopropyl-methylamine [DAMP]), kidney biopsies were processed for immunoelectron microscopy. Antibodies directed at monoclonal lambda light chains, mannose-6-phosphate cation-independent receptor (MPR) and DAMP were used.Labelling density (number

Ana Lucia Nicastri; Maria José Brandão de Almeida Prado; Antonio Sesso; Euthymia Brandão de Almeida Prado

1998-01-01

314

Exocrine pancreatic function following proximal small bowel resection in rats.  

PubMed Central

1. In order to assess if proximal enterectomy induces changes in the function of the exocrine pancreas, the exocrine pancreas was studied 1 week, 4 weeks, and 6 months after 50 or 75% proximal small bowel resection. 2. One week after 50 and 75% proximal small bowel resections, basal pancreatic bicarbonate outputs, studied by means of an external pancreatic fistula in conscious rats, were increased significantly over control values by 43 and 78% respectively. Four weeks after a 75% resection, the bicarbonate output was still significantly higher in resected animals than in sham operated animals. 3. The increase of volume and bicarbonate of the basal pancreatic secretion coincided with a 4-fold increase in plasma secretin concentration 1 week after resection. Both increased pancreatic secretion and plasma secretin concentration were transient. 4. The pancreatic hypersecretion was specifically reversed to control values with an I.P. injection of jejunoileal mucosa homogenate. 5. Serum gastrin and somatostatin values in intestinal mucosa and pancreas were not changed 1 and 4 weeks after enterectomy compared with sham operated animals. 6. The weight of the pancreas and its content of DNA were unaltered by resection. Amylase and chymotrypsinogen per gram pancreatic tissue and per microgram DNA were reduced 4 weeks following resections as compared with sham operated rats. After 6 months, chymotrypsinogen appeared further reduced in resected animals. 7. It is concluded that extensive proximal enterectomy in rats produced early, transient and marked increases in basal pancreatic water and bicarbonate secretion and in plasma secretin due to the loss of jejunoileal inhibitor(s), and a selective decrease in certain enzymes in pancreatic tissue. PMID:6121911

Gelinas, M D; Morin, C L; Morisset, J

1982-01-01

315

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

2013-09-01

316

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. PMID:23852138

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

2013-01-01

317

A Risk Profile for Advanced Proximal Neoplasms on Diagnostic Colonoscopy  

Microsoft Academic Search

The capacity for colonoscopy is limited and a method to prioritize patients for diagnostic colonoscopy is needed in health\\u000a care centers. A retrospective cross-sectional cohort study was carried out in county and community endoscopy centers, which\\u000a included 1,065 county and 279 community patients aged ?40 years undergoing diagnostic colonoscopy. We constructed a risk profile\\u000a for proximal advanced neoplasms on diagnostic

Thomas M. Zarchy; Frank Tsai; Emily Ramicone; Linda S. Chan

2009-01-01

318

[Proximal colostomy in multistage treatment of complicated colonic diverticulosis].  

PubMed

On the basis of experience in surgical treatment of 128 patients with colonic diverticulosis who had a proximal colostoma which was formed earlier for acute complications of the process, it is shown that colostomy is inadequate as an independent method for the management of complicated diverticulosis. Resection or exteriorization of the involved segment of the large intestine is necessary in such cases. The formation of entero-enterostomy is hazardous and inexpedient in that event. PMID:9511294

Salamov, K N; Achkasov, S I; Soltanov, B Ts

1998-01-01

319

Human proximal femur bone adaptation to variations in hip geometry.  

PubMed

The study of bone mass distribution at proximal femur may contribute to understand the role of hip geometry on hip fracture risk. We examined how bone mineral density (BMD) of proximal femur adapts to inter individual variations in the femoral neck length (FNL), femoral neck width (FNW) and neck shaft angle (NSA). A parameterized and dimensionally scalable 3-D finite element model of a reference proximal femur geometry was incrementally adjusted to adopt physiological ranges at FNL (3.90-6.90cm), FNW (2.90-3.46cm), and NSA (109-141º), yielding a set of femora with different geometries. The bone mass distribution for each femur was obtained with a suitable bone remodelling model. The BMDs at the integral femoral neck (FN) and at the intertrochanteric (ITR) region, as well as the BMD ratio of inferomedial to superolateral (IM:SL) regions of FN and BMD ratio of FN:ITR were used to represent bone mass distribution. Results revealed that longer FNLs present greater BMD (g/cm(3)) at the FN, mainly at the SL region, and at the ITR region. Wider FNs were associated with reduced BMD at the FN, particularly at the SL region, and at the ITR region. Larger NSAs up to 129° were associated with BMD diminutions at the FN and ITR regions and with increases of the IM:SL BMD ratio while NSAs larger than 129° resulted in decrease of the IM:SL BMD ratio. These findings suggest hip geometry as moderator of the mechanical loading influence on bone mass distribution at proximal femur with higher FNL favoring the BMD of FN and ITR regions and greater FNW and NSA having the opposite effect. Augmented values of FNL and FNW seem also to favor more the BMD at the superolateral than at the inferomedial FN region. PMID:25016094

Machado, M M; Fernandes, P R; Zymbal, V; Baptista, F

2014-10-01

320

Diadenosine polyphosphate-stimulated gluconeogenesis in isolated rat proximal tubules.  

PubMed Central

Diadenosine polyphosphates released into the extracellular environment influence a variety of metabolic and other cellular activities in a wide range of target tissues. Here we have studied the impact of these novel nucleotides on gluconeogenesis in isolated rat proximal tubules. Gluconeogenesis was stimulated following exposure of isolated proximal tubules to a range of adenine-containing nucleotides including ADP, ATP, Ap3A, Ap4A, Ap5A and Ap6A. The concentration-dependence of ATP-, Ap3A- and Ap4A-mediated stimulation of gluconeogenesis was similar and was consistent with a role for these agents in the physiological control of renal metabolism. Nucleotide-stimulated gluconeogenesis was diminished in the presence of agents that interfere with phospholipase C activation or intracellular Ca2+ metabolism, indicative of a role for polyphosphoinositide-mediated Ca2+ mobilization in the mechanism of action of ATP, Ap3A and Ap4A. The characteristics of binding of [2-3H]Ap4A to renal plasma-membrane preparations suggest that Ap4A mediates its effects on proximal tubule gluconeogenesis via interaction with P2y-like purinoceptor(s) also recognized by extracellular ATP. PMID:9163337

Edgecombe, M; Craddock, H S; Smith, D C; McLennan, A G; Fisher, M J

1997-01-01

321

Automated induction of heterogeneous proximity measures for supervised spectral embedding.  

PubMed

Spectral embedding methods have played a very important role in dimensionality reduction and feature generation in machine learning. Supervised spectral embedding methods additionally improve the classification of labeled data, using proximity information that considers both features and class labels. However, these calculate the proximity information by treating all intraclass similarities homogeneously for all classes, and similarly for all interclass samples. In this paper, we propose a very novel and generic method which can treat all the intra- and interclass sample similarities heterogeneously by potentially using a different proximity function for each class and each class pair. To handle the complexity of selecting these functions, we employ evolutionary programming as an automated powerful formula induction engine. In addition, for computational efficiency and expressive power, we use a compact matrix tree representation equipped with a broad set of functions that can build most currently used similarity functions as well as new ones. Model selection is data driven, because the entire model is symbolically instantiated using only problem training data, and no user-selected functions or parameters are required. We perform thorough comparative experimentations with multiple classification datasets and many existing state-of-the-art embedding methods, which show that the proposed algorithm is very competitive in terms of classification accuracy and generalization ability. PMID:24808595

Rodriguez-Martinez, Eduardo; Mu, Tingting; Jiang, Jianmin; Goulermas, John Yannis

2013-10-01

322

Elevated oxidized glutathione in cystinotic proximal tubular epithelial cells.  

PubMed

Cystinosis, the most frequent cause of inborn Fanconi syndrome, is characterized by the lysosomal cystine accumulation, caused by mutations in the CTNS gene. To elucidate the pathogenesis of cystinosis, we cultured proximal tubular cells from urine of cystinotic patients (n = 9) and healthy controls (n = 9), followed by immortalization with human papilloma virus (HPV E6/E7). Obtained cell lines displayed basolateral polarization, alkaline phosphatase activity, and presence of aminopeptidase N (CD-13) and megalin, confirming their proximal tubular origin. Cystinotic cell lines exhibited elevated cystine levels (0.86 +/- 0.95 nmol/mg versus 0.09 +/- 0.01 nmol/mg protein in controls, p = 0.03). Oxidized glutathione was elevated in cystinotic cells (1.16 +/- 0.83 nmol/mg versus 0.29 +/- 0.18 nmol/mg protein, p = 0.04), while total glutathione, free cysteine, and ATP contents were normal in these cells. In conclusion, elevated oxidized glutathione in cystinotic proximal tubular epithelial cell lines suggests increased oxidative stress, which may contribute to tubular dysfunction in cystinosis. PMID:16202976

Wilmer, Martijn J G; de Graaf-Hess, Adriana; Blom, Henk J; Dijkman, Henry B P M; Monnens, Leo A; van den Heuvel, Lambertus P; Levtchenko, Elena N

2005-11-18

323

Indirect reduction and composite fixation of extraarticular proximal tibial fractures.  

PubMed

Forty-one extraarticular comminuted proximal tibial fractures were treated during a 7-year period. The fractures were proximal tibial metaphyseal injuries or metaphyseal-diaphyseal junction injuries with extension proximally and distally but not involving the knee joint. All fractures were treated surgically with open reduction and internal fixation using an indirect reduction technique with a lateral plate, and a medial substitution external fixator concomitantly. All fractures were seen for followup until they healed (average healing time, 12.1 weeks). The timing of internal fixation was based on the status of the soft tissue (average time to surgery, 8.5 days after injury). A temporary spanning external fixator was used in 17 (41.5%) fractures to allow for further assessment, demarcation, and improvement of the anterior soft tissues. There were 3 (7%) delayed unions, 1 (2%) malunion, and no nonunions. There were 2 (5%) wound infections and 5 (12%) pin track problems. One postsurgical soft tissue problem was encountered. Through this technique, reliable healing and alignment were achieved in this often difficult fracture pattern, particularly for fractures that were difficult or impossible to treat with an intermedullary nail. PMID:7634689

Bolhofner, B R

1995-06-01

324

Hand proximity facilitates spatial discrimination of auditory tones  

PubMed Central

The effect of hand proximity on vision and visual attention has been well documented. In this study we tested whether such effect(s) would also be present in the auditory modality. With hands placed either near or away from the audio sources, participants performed an auditory-spatial discrimination (Experiment 1: left or right side), pitch discrimination (Experiment 2: high, med, or low tone), and spatial-plus-pitch (Experiment 3: left or right; high, med, or low) discrimination task. In Experiment 1, when hands were away from the audio source, participants consistently responded faster with their right hand regardless of stimulus location. This right hand advantage, however, disappeared in the hands-near condition because of a significant improvement in left hand's reaction time (RT). No effect of hand proximity was found in Experiments 2 or 3, where a choice RT task requiring pitch discrimination was used. Together, these results that the perceptual and attentional effect of hand proximity is not limited to one specific modality, but applicable to the entire “space” near the hands, including stimuli of different modality (at least visual and auditory) within that space. While these findings provide evidence from auditory attention that supports the multimodal account originally raised by Reed et al. (2006), we also discuss the possibility of a dual mechanism hypothesis to reconcile findings from the multimodal and magno/parvocellular account. PMID:24966839

Tseng, Philip; Yu, Jiaxin; Tzeng, Ovid J. L.; Hung, Daisy L.; Juan, Chi-Hung

2014-01-01

325

Proximal Neuropathic Lesions in Distal Symmetric Diabetic Polyneuropathy  

PubMed Central

OBJECTIVE This study investigated high-resolution magnetic resonance neurography (MRN) in distal symmetric diabetic polyneuropathy (dPNP). RESEARCH DESIGN AND METHODS MRN comprised high-resolution transaxial imaging of peripheral nerves of the lower limbs in 20 patients with type 2 diabetes (10 with dPNP, type 2/dPNP[+], and 10 without dPNP, type 2/dPNP[?]), seven patients with type 1 diabetes (two with dPNP, type 1/dPNP[+], five without dPNP, type 1/dPNP[?]), and 10 nondiabetic control subjects. Intraneural T2 lesions, as the main diagnostic criterion of MRN, were detected visually by two independent observers and quantitatively by analysis of T2 contrast ratios. RESULTS Multifocal fascicular, symmetric intraneural T2 lesions occurred in the proximal trunks of sciatic nerves in four patients (three with type 2/dPNP[+] and one with type 1/dPNP[+]) but not in control subjects (type 2/dPNP[?], type 1/dPNP[?], nondiabetic control subjects), which was confirmed by quantitative analysis. Clinical severity was higher in patients with T2 lesions (neuropathy deficit score: 10 vs. 7.8; P = 0.05). CONCLUSIONS For the first time, proximal neuropathic lesions of dPNP are reported in vivo. This supports that accumulation of proximal, multifocal fascicular injury may be important in disease progression. PMID:21266652

Pham, Mirko; Oikonomou, Dimitrios; Bäumer, Philipp; Bierhaus, Angelika; Heiland, Sabine; Humpert, Per M.; Nawroth, Peter P.; Bendszus, Martin

2011-01-01

326

Allograft reconstruction for symptomatic chronic complete proximal hamstring tendon avulsion.  

PubMed

Complete proximal hamstring tendon avulsion is an uncommon injury that can cause significant disability in young, athletic individuals. Surgical reattachment is recommended and can be performed on a delayed basis if the tissue is sufficiently mobile. We report 2-year follow up for two cases where interpositional allograft tissue was used for reconstruction because the tendon was too retracted for primary repair. Two 30-year-old patients with complete proximal hamstring avulsion at least 2 years earlier reported severe hamstring weakness and restrictions with respect to sport and recreational activities. Proximal hamstring tendon reconstruction with Achilles tendon allograft was performed for both patients. They were immobilized for 8 weeks with the hip in extension and the knee in flexion using a custom orthosis, followed by physical therapy and weight bearing as tolerated. The patients were followed for over 2 years after the surgery and were evaluated with physical examination, isokinetic strength testing and detailed questions about their function. Following the procedure, both patients returned to a more active lifestyle that was greatly improved with respect to participation in sport and function. This procedure should be considered as a salvage operation as the patients did not return to completely normal function and demonstrated hamstring weakness on the operated side. PMID:18682918

Marx, Robert G; Fives, Gregory; Chu, Samuel K; Daluiski, Aaron; Wolfe, Scott W

2009-01-01

327

Decoherence of proximate nuclear spin qubits in natural silicon  

E-print Network

Hybrid qubit systems combining electronic spins with surrounding proximate nuclear spins registers offer a promising avenue towards quantum information processing, with even multi-spin error correction protocols recently demonstrated in diamond. For the important platform offered by cryogenically cooled spins of donors in natural silicon such as phosphorus Si:P, however, the coherence behaviour of proximate nuclear spins are not well understood. We propose here that there may be an important contribution from a few (of order 100 spin pairs) symmetrically sited nuclear spin impurity pairs ("equivalent pairs"), which were not previously considered, as their effect is negligible outside the frozen core around an electron. If equivalent pairs represent a measurable source of decoherence, nuclear coherence decays could provide sensitive probes of the symmetries of electronic wavefunctions. We compare this model with the effect of a very large nuclear spin bath (10^8 weakly contributing pairs) outside the frozen core. We obtain T_{2n} values of order 1 second for both models, confirming the suitability of proximate nuclei in silicon as very long-lived spin qubits, in either case.

R. Guichard; S. J. Balian; G. Wolfowicz; P. A. Mortemousque; John J. L. Morton; T. S. Monteiro

2015-03-14

328

Proximity-Dependent Inhibition in Escherichia coli Isolates from Cattle?  

PubMed Central

We describe a novel proximity-dependent inhibition phenotype of Escherichia coli that is expressed when strains are cocultured in defined minimal media. When cocultures of “inhibitor” and “target” strains approached a transition between logarithmic and stationary growth, target strain populations rapidly declined >4 log CFU per ml over a 2-h period. Inhibited strains were not affected by exposure to conditioned media from inhibitor and target strain cocultures or when the inhibitor and target strains were incubated in shared media but physically separated by a 0.4-?m-pore-size membrane. There was no evidence of lytic phage or extracellular bacteriocin involvement, unless the latter was only present at effective concentrations within immediate proximity of the inhibited cells. The inhibitory activity observed in this study was effective against a diversity of E. coli strains, including enterohemorrhagic E. coli serotype O157:H7, enterotoxigenic E. coli expressing F5 (K99) and F4 (K88) fimbriae, multidrug-resistant E. coli, and commensal E. coli. The decline in counts of target strains in coculture averaged 4.8 log CFU/ml (95% confidence interval, 4.0 to 5.5) compared to their monoculture counts. Coculture of two inhibitor strains showed mutual immunity to inhibition. These results suggest that proximity-dependent inhibition can be used by bacteria to gain a numerical advantage when populations are entering stationary phase, thus setting the stage for a competitive advantage when growth conditions improve. PMID:21296941

Sawant, Ashish A.; Casavant, N. Carol; Call, Douglas R.; Besser, Thomas E.

2011-01-01

329

The proximal tubule in the pathophysiology of the diabetic kidney  

PubMed Central

Diabetic nephropathy is a leading cause of end-stage renal disease. A better understanding of the molecular mechanism involved in the early changes of the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. This review focuses on the proximal tubule in the early diabetic kidney, particularly on its exposure and response to high glucose levels, albuminuria, and other factors in the diabetic glomerular filtrate, the hyperreabsorption of glucose, the unique molecular signature of the tubular growth phenotype, including aspects of senescence, and the resulting cellular and functional consequences. The latter includes the local release of proinflammatory chemokines and changes in proximal tubular salt and fluid reabsorption, which form the basis for the strong tubular control of glomerular filtration in the early diabetic kidney, including glomerular hyperfiltration and odd responses like the salt paradox. Importantly, these early proximal tubular changes can set the stage for oxidative stress, inflammation, hypoxia, and tubulointerstitial fibrosis, and thereby for the progression of diabetic renal disease. PMID:21228342

2011-01-01

330

Research on the virtual simulation and testing technology of capacitance proximity fuze  

Microsoft Academic Search

Simulation technology of capacitance proximity fuze plays a very important role in the development and application of capacitance proximity fuze. In this paper, the simulation principle of capacitance proximity fuze is analysed. The hardware of simulation and testing system is designed, which is constituted of demodulation signal output circuit, interface circuit and signal regulation circuit. The virtual simulation and testing

Chengtian Song; Yuxian Bai; Keyong Wang

2008-01-01

331

Behavioral Detection and Containment of Proximity Malware in Delay Tolerant Networks  

E-print Network

Behavioral Detection and Containment of Proximity Malware in Delay Tolerant Networks Wei Peng, Feng alternative to the traditional infrastructural model. Proximity malware, which exploits the temporal dimension address the proximity malware detection and containment problem with explicit consideration for the unique

Wu, Jie

332

Foreign Direct Investment, Intra-organizational Proximity, and Technological Capability: The Case of China's Automobile Industry  

E-print Network

Foreign Direct Investment, Intra-organizational Proximity, and Technological Capability: The Case parents . #12;4 #12;5 Foreign Direct Investment, Intra-organizational Proximity, and Technological direct investment (FDI), intra-organizational proximity, and in-house technology development performances

333

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

334

Proximal extent of pelvic vein thrombosis and its association with pulmonary embolism  

Microsoft Academic Search

Objective: Conventional methods such as duplex ultrasound scanning do not provide accurate information about proximal extension of pelvic vein thrombosis. We evaluated proximal extent of thrombus toward pelvic veins with magnetic resonance imaging in patients with suspected deep vein thrombosis (DVT) proximal to the inguinal ligament on the basis of duplex ultrasound scans. In addition, frequency of pulmonary embolism (PE)

Barbara Borst-Krafek; Astrid Maria Fink; Claudia Lipp; Helmut Umek; Horst Köhn; Andreas Steiner

2003-01-01

335

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

Microsoft Academic Search

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

Hugh R Brady; Bruce C Kone; Robert M Brenner; Steven R Gullans

1989-01-01

336

Deriving the number of jobs in proximity services from the number of inhabitants in French rural  

E-print Network

Deriving the number of jobs in proximity services from the number of inhabitants in French rural a minimum requirement approach to derive the number of jobs of proximity services per inhabitant observe that the minimum number of service jobs per inhabitant (interpreted as jobs of proximity services

Paris-Sud XI, Université de

337

Measurement of the load behaviour in a dry pilot mill using an inductive proximity probe  

Microsoft Academic Search

Load behaviour in a dry pilot mill has been successfully measured as a function of mill speed and load filling using an inductive proximity probe. The inductive proximity probe detects the presence of metallic objects in the proximity of its sensing face. Static and dynamic test demonstrate that it is suitable in measuring load behaviour. The shoulder position is measured

Kiangi K. Kiangi; Michael H. Moys

2006-01-01

338

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

339

Binding of Src to Na\\/K-ATPase Forms a Functional Signaling Complex  

Microsoft Academic Search

We have shown that ouabain activates Src, resulting in subsequent tyrosine phosphorylation of multiple effectors. Here, we tested if the Na\\/K-ATPase and Src can form a functional signaling complex. In LLC-PK1 cells the Na\\/K-ATPase and Src colocalized in the plasma membrane. Fluorescence resonance energy transfer analysis indicated that both proteins were in close proximity, suggesting a direct interaction. GST pulldown

Jiang Tian; Ting Cai; Zhaokan Yuan; Haojie Wang; Lijun Liu; Michael Haas; Elena Maksimova; Xin-Yun Huang; Zi-Jian Xie

2006-01-01

340

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

341

Superconducting proximity effect in InAs nanowires  

NASA Astrophysics Data System (ADS)

First discovered by Holm and Meissner in 1932, the superconducting proximity effect has remained a subject of experimental and theoretical interest. In recent years, it has been proposed that proximity effect in a semiconductor with large g-factor and spin-orbit coupling could lead to exotic phases of superconductivity. This thesis focuses on proximity effect in one of the prime semiconductor candidates---InAs nanowires. The first set of experiments investigates the superconducting phase-dependent tunneling spectrum of a proximitized InAs quantum dot. We observe tunneling resonances of Andreev bound states in the Kondo regime, and induce quantum phase transitions of the quantum dot ground state with gate voltage and phase bias---the latter being the first experimental observation of its kind. An additional zero-bias peak of unknown origin is observed to coexist with the Andreev bounds states. The second set of experiments extends upon the first with sharper tunneling resonances and an increase in the device critical field. By applying an external magnetic field, we observe spin-resolved Andreev bound states in proximitized InAs quantum dots. From the linear splitting of the tunneling resonances, we extract g-factors of 5 and 10 in two different devices. The third set of experiments utilizes a novel type of epitaxial core-shell InAs-Al nanowire. We compare the induced gaps of these nanowires with control devices proximitized with evaporated Al films. Our results show that the epitaxial core-shell nanowires possess a much harder induced gap---up to two orders of magnitude in sub-gap conductance suppression as compared to a factor of five in evaporated control devices. This observation suggests that roughness in S-N interfaces plays a crucial role in the quality of the proximity effect. The fourth set of experiments investigates the gate-tunability of epitaxial half-shell nanowires. In a half-shell nanowire Josephson junction, we measure the normal state resistance, maximum supercurrent, and magnetic field-dependent supercurrent interference patterns. The gate dependences of these independent experimental parameters are consistent with one another and indicate that an InAs nanowire in good ohmic contact to a thin sliver of Al retains its proximity effect and is gate-tunable.

Chang, Willy

342

Signaling pathways involved with the stimulatory effect of angiotensin II on vacuolar H+-ATPase in proximal tubule cells.  

PubMed

It has been documented that angiotensin II (ANG II) (10(-9) M) stimulates proton extrusion via H(+)-adenosine triphosphatase (ATPase) in proximal tubule cells. In the present study, we investigated the signaling pathways involved in the effects of ANG II on H(+)-ATPase activity and on the cytosolic free calcium concentration in immortalized rat proximal tubule cells, a permanent cell line derived from rat proximal tubules. The effects of ANG on pH(i) and [Ca(+2)](i) were assessed by the fluorescent probes, 2',7-bis (2-carboxyethyl)-5(6)-carboxyfluorescein-acetoxy-methyl ester and fluo-4-acetoxy-methyl ester, in the absence of Na(+) to block the Na(+)/H(+) exchanger. In the control situation, the pH recovery rate following intracellular acidification with NH(4)Cl was 0.073+/-0.011 pH units/min (n=12). This recovery was significantly increased with ANG II (10(-9 )M), to 0.12+/-0.015 pH units/min, n=10. This last effect was also followed by a significant increase of Ca(+2) (i), from 99.72+/-1.704 nM (n=21) to 401.23+/-33.91 nM (n=39). The stimulatory effect of ANG II was blocked in the presence of losartan, an angiotensin II subtype 1 (AT(1)) receptor antagonist. H89 [protein kinase A (PKA) inhibitor] plus ANG II had no effect on the pH recovery. Staurosporine [protein kinase C (PKC) inhibitor] impaired the effect of ANG II. Phorbol myristate acetate (PKC activator) mimicked in part the stimulatory effect of ANG II, but reduced Ca(+2) (i). 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (intracellular calcium chelator) alone reduced the pH(i) recovery rate below control levels and impaired the effect of ANG II, in a way similar to that of trimethoxy benzoate (a blocker of Ca(+2) (i) mobilization). We conclude that ANG II regulates rat proximal tubule vacuolar H(+)-ATPase by a PKA-independent mechanism and that PKC and intracellular calcium play a critical role in this regulation. PMID:16680484

Carraro-Lacroix, Luciene Regina; Malnic, Gerhard

2006-09-01

343

Mechanism of ?-Conotoxin PIIIA Binding to the Voltage-Gated Na+ Channel NaV1.4  

PubMed Central

Several subtypes of voltage-gated Na+ (NaV) channels are important targets for pain management. ?-Conotoxins isolated from venoms of cone snails are potent and specific blockers of different NaV channel isoforms. The inhibitory effect of ?-conotoxins on NaV channels has been examined extensively, but the mechanism of toxin specificity has not been understood in detail. Here the known structure of ?-conotoxin PIIIA and a model of the skeletal muscle channel NaV1.4 are used to elucidate elements that contribute to the structural basis of ?-conotoxin binding and specificity. The model of NaV1.4 is constructed based on the crystal structure of the bacterial NaV channel, NaVAb. Six different binding modes, in which the side chain of each of the basic residues carried by the toxin protrudes into the selectivity filter of NaV1.4, are examined in atomic detail using molecular dynamics simulations with explicit solvent. The dissociation constants (Kd) computed for two selected binding modes in which Lys9 or Arg14 from the toxin protrudes into the filter of the channel are within 2 fold; both values in close proximity to those determined from dose response data for the block of NaV currents. To explore the mechanism of PIIIA specificity, a double mutant of NaV1.4 mimicking NaV channels resistant to ?-conotoxins and tetrodotoxin is constructed and the binding of PIIIA to this mutant channel examined. The double mutation causes the affinity of PIIIA to reduce by two orders of magnitude. PMID:24676211

Chen, Rong; Robinson, Anna; Chung, Shin-Ho

2014-01-01

344

Posterior shoulder dislocation with ipsilateral proximal humerus type 2 physeal fracture: case report.  

PubMed

In pediatric patients, proximal humeral physeal fractures are uncommon injuries compared with distal physeal fractures. Usually, the growth plate is the most vulnerable site of fracture in the proximal humerus. Proximal humeral physeal fractures accompanying posterior shoulder dislocation are very rare. There are few recent reports on the combination of glenohumeral dislocation and proximal humerus fractures. Here, we describe a case of posterior shoulder dislocation with ipsilateral proximal humerus type 2 physeal fracture in a 9-year-old boy. We treated the patient by closed reduction and percutaneous pinning under general anesthesia. PMID:25714939

Hong, Sijohn; Nho, Jae-Hwi; Lee, Chang-Ju; Kim, Jun-Bum; Kim, ByungSung; Choi, Hyung-Suk

2015-05-01

345

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

346

Arteriovenous graft with outflow in the proximal axillary vein.  

PubMed

Arteriovenous access can result in complications including extremity ischemia and swelling. Use of the nondominant upper extremity is preferred because complications will result in less severe disability. The distal axillary vein in the axilla is usually considered to be the end point for arteriovenous access in the upper extremity. Vascular surgeons are familiar with exposure of the proximal axillary artery via an infraclavicular incision. The axillary vein is also easily exposed through this technique. Use of this vein for arteriovenous graft outflow can preserve the dominant arm for future use. Nine patients with arteriovenous grafts with venous outflow in the proximal arm for future use. All patients had exposure to the proximal axillary vein via an infraclavicular incision. There were six women and three men. All patients had multiple failed access in the ipsilateral extremity. One patient had a loop configuration graft, while the six others had a straight graft with arterial inflow via the brachial artery. One patient had a bovine mesenteric vein graft, while the remaining six had expanded polytetrafluoroethylene grafts. Six of the seven patients had ambulatory surgery, while one patient was admitted postoperatively with mental status changes. Patency rates were 78%, with mean follow-up of 16 months. One patient had early failure due to steal and one patient failed at 22 months. Six of seven patients are alive at current follow-up. Three patients required secondary procedures including venous angioplasty (n=2) and subclavian artery stenting (n=1). The infraclavicular axillary vein can be used as an effective outflow for arteriovenous grafts. This procedure can be done as an outpatient surgery with a low complication rate. This procedure can preserve the dominant arm for future access and provides a possible alternative to surgery on another extremity. PMID:18809289

Teruya, Theodore H; Schaeffer, David; Abou-Zamzam, Ahmed M; Bianchi, Christian

2009-01-01

347

The proximate causes of sexual size dimorphism in Phrynocephalus przewalskii.  

PubMed

Sexual size dimorphism (SSD) is a common phenomenon and is a central topic in evolutionary biology. Recently, the importance of pursuing an ontogenetic perspective of SSD has been emphasized, to elucidate the proximate physiological mechanisms leading to its evolution. However, such research has seldom focused on the critical periods when males and females diverge. Using mark-recapture data, we investigated the development of SSD, sex-specific survivorship, and growth rates in Phrynocephalus przewalskii (Agamidae). We demonstrated that both male and female lizards are reproductively mature at age 10-11 months (including 5 months hibernation). Male-biased SSD in snout-vent length (SVL) was only found in adults and was fully expressed at age 11 months (June of the first full season of activity), just after sexual maturation. However, male-biased SSD in tail length (TL), hind-limb length (LL), and head width (HW) were fully expressed at age 9-10 months, just before sexual maturation. Analysis of age-specific linear growth rates identified sexually dimorphic growth during the fifth growth month (age 10-11 months) as the proximate cause of SSD in SVL. The males experienced higher mortality than females in the first 2 years and only survived better than females after SSD was well developed. This suggests that the critical period of divergence in the sizes of male and female P. przewalskii occurs between 10 and 11 months of age (May to June during the first full season of activity), and that the sexual difference in growth during this period is the proximate cause. However, the sexual difference in survivorship cannot explain the male-biased SSD in SVL. Our results indicate that performance-related characteristics, such as TL, HW, and LL diverged earlier than SVL. The physiological mechanisms underlying the different growth patterns of males and females may reflect different energy allocations associated with their different reproductive statuses. PMID:24465815

Zhao, Wei; Liu, Nai-Fa

2014-01-01

348

Proximity Effects and Nonequilibrium Superconductivity in Transition-Edge Sensors  

NASA Technical Reports Server (NTRS)

We have recently shown that normal-metal/superconductor (N/S) bilayer TESs (superconducting Transition-Edge Sensors) exhibit weak-link behavior.l Here we extend our understanding to include TESs with added noise-mitigating normal-metal structures (N structures). We find TESs with added Au structures also exhibit weak-link behavior as evidenced by 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) 1, 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 Mol Au bilayer TESs with lengths ranging from 8 to 130 {\\mu}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 \\times 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.

2011-01-01

349

Uncemented allograft–prosthetic composite reconstruction of the proximal femur  

PubMed Central

Background: Allograft–prosthetic composite can be divided into three groups names cemented, uncemented, and partially cemented. Previous studies have mainly reported outcomes in cemented and partially cemented allograft–prosthetic composites, but have rarely focused on the uncemented allograft–prosthetic composites. The objectives of our study were to describe a surgical technique for using proximal femoral uncemented allograft–prosthetic composite and to present the radiographic and clinical results. Materials and Methods: Twelve patients who underwent uncemented allograft–prosthetic composite reconstruction of the proximal femur after bone tumor resection were retrospectively evaluated at an average followup of 24.0 months. Clinical records and radiographs were evaluated. Results: In our series, union occurred in all the patients (100%; range 5-9 months). Until the most recent followup, there were no cases with infection, nonunion of the greater trochanter, junctional bone resorption, dislocation, allergic reaction, wear of acetabulum socket, recurrence, and metastasis. But there were three periprosthetic fractures which were fixed using cerclage wire during surgery. Five cases had bone resorption in and around the greater trochanter. The average Musculoskeletal Tumor Society (MSTS) score and Harris hip score (HHS) were 26.2 points (range 24-29 points) and 80.6 points (range 66.2-92.7 points), respectively. Conclusions: These results showed that uncemented allograft–prosthetic composite could promote bone union through compression at the host–allograft junction and is a good choice for proximal femoral resection. Although this technology has its own merits, long term outcomes are yet not validated. PMID:24932036

Min, Li; Peng, Jing; Duan, Hong; Zhang, Wenli; Zhou, Yong; Tu, Chongqi

2014-01-01

350

Survivin Mediates Renal Proximal Tubule Recovery from AKI  

PubMed Central

AKI induces the renoprotective upregulation of survivin expression in kidney epithelial cells, but the underlying mechanisms have not been identified. To determine the role of survivin in renal recovery from AKI, we generated mice with renal proximal tubule-specific deletion of survivin (survivinptKO). Renal survivin expression increased substantially in response to ischemia-reperfusion (I/R) injury in control littermates but remained minimal in survivinptKO mice. Functional and histologic data indicated similar degrees of renal injury in survivinptKO and control mice 24 hours after reperfusion, but recovery was markedly delayed in survivinptKO mice. In MCT cells, a mouse renal proximal tubule cell line, ATP depletion by antimycin A treatment upregulated survivin expression through a phospho-STAT3–dependent pathway. In wild-type mice, inhibition of STAT3 kinase diminished I/R-induced upregulation of STAT3 phosphorylation and survivin expression and delayed recovery. Furthermore, I/R injury activated Notch-2 signaling, and a ?-secretase inhibitor suppressed I/R-induced Notch-2 signaling, STAT3 phosphorylation, and survivin expression and delayed recovery. In MCT cells, inhibition of ?-secretase similarly attenuated antimycin A-induced Notch-2 activation, upregulation of survivin, and phosphorylation of STAT3, but STAT3 kinase inhibition did not prevent Notch-2 activation. Therefore, these data suggest that STAT3 phosphorylation and subsequent upregulation of survivin expression mediated by Notch-2 signaling in renal proximal tubule epithelial cells aid in the functional and structural recovery of the kidney from AKI. PMID:23949800

Chen, Jianchun; Chen, Jian-Kang; Conway, Edward M.

2013-01-01

351

Efficiency of the Lausanne Clinical Pathway for Proximal Femoral Fractures  

PubMed Central

Purpose/Introduction: The number of hip fractures is rising, due to increases in life expectancy. In such cases, patients are at risk from post-operative complications and subsequently the average length of hospitalization may be extended. In 2011, we established a clinical pathway (CP), a specific model of care for patient-care management, to improve the clinical and economic outcomes of proximal femoral fracture management in elderly patients. The goal was to evaluate the CP using clinical, process, and financial indicators. Methods: We included all surgical patients aged 65 and over, admitted to the emergency department with a fracture of the proximal femur following a fall. Assessment parameters included three performance indicators: clinical, process, and financial. The clinical indicators were the presence or absence of acute delirium on the third post-operative day, diagnosis of nosocomial pneumonia, and the number of patients fulfilling at least 75% of their nutritional requirements at the end of the hospitalization period. The process indicator was the time interval between arrival at the emergency department and surgery. The financial indicator was based on the number of days spent in hospital. Results: From 2011 to 2013, 669 patients were included in the CP. We observed that the average length of stay in hospital decreased as soon as the CP was implemented and stabilized afterwards. The goal of 90% of patients undergoing surgery within 48?h of arrival in the emergency department was surpassed in 2013 (93.1%). Furthermore, we observed an improvement in the clinical indicators. Conclusion: The application of a CP allowed an improvement in the qualitative and quantitative efficiency of proximal femoral fracture management in elderly patients, in terms of clinical, process, and financial factors.

Fleury, Nicole; Chevalley, François; Rubli, Eve; Coti, Pauline; Farron, Alain; Jolles, Brigitte M.

2015-01-01

352

The Proximate Causes of Sexual Size Dimorphism in Phrynocephalus przewalskii  

PubMed Central

Sexual size dimorphism (SSD) is a common phenomenon and is a central topic in evolutionary biology. Recently, the importance of pursuing an ontogenetic perspective of SSD has been emphasized, to elucidate the proximate physiological mechanisms leading to its evolution. However, such research has seldom focused on the critical periods when males and females diverge. Using mark-recapture data, we investigated the development of SSD, sex-specific survivorship, and growth rates in Phrynocephalus przewalskii (Agamidae). We demonstrated that both male and female lizards are reproductively mature at age 10–11 months (including 5 months hibernation). Male-biased SSD in snout-vent length (SVL) was only found in adults and was fully expressed at age 11 months (June of the first full season of activity), just after sexual maturation. However, male-biased SSD in tail length (TL), hind-limb length (LL), and head width (HW) were fully expressed at age 9–10 months, just before sexual maturation. Analysis of age-specific linear growth rates identified sexually dimorphic growth during the fifth growth month (age 10–11 months) as the proximate cause of SSD in SVL. The males experienced higher mortality than females in the first 2 years and only survived better than females after SSD was well developed. This suggests that the critical period of divergence in the sizes of male and female P. przewalskii occurs between 10 and 11 months of age (May to June during the first full season of activity), and that the sexual difference in growth during this period is the proximate cause. However, the sexual difference in survivorship cannot explain the male-biased SSD in SVL. Our results indicate that performance-related characteristics, such as TL, HW, and LL diverged earlier than SVL. The physiological mechanisms underlying the different growth patterns of males and females may reflect different energy allocations associated with their different reproductive statuses. PMID:24465815

Zhao, Wei; Liu, Nai-fa

2014-01-01

353

The proximate unit in Chinese handwritten character production  

PubMed Central

In spoken word production, a proximate unit is the first phonological unit at the sublexical level that is selectable for production (O'Seaghdha et al., 2010). The present study investigated whether the proximate unit in Chinese handwritten character production is the stroke, the radical, or something in between. A written version of the form preparation task was adopted. Chinese participants learned sets of two-character words, later were cued with the first character of each word, and had to write down the second character (the target). Response times were measured from the onset of a cue character to the onset of a written response. In Experiment 1, the target characters within a block shared (homogeneous) or did not share (heterogeneous) the first stroke. In Experiment 2, the first two strokes were shared in the homogeneous blocks. Response times in the homogeneous blocks and in the heterogeneous blocks were comparable in both experiments (Experiment 1: 687 vs. 684 ms, Experiment 2: 717 vs. 716). In Experiment 3 and 4, the target characters within a block shared or did not share the first radical. Response times in the homogeneous blocks were significantly faster than those in the heterogeneous blocks (Experiment 3: 685 vs. 704, Experiment 4: 594 vs. 650). In Experiment 5 and 6, the shared component was a Gestalt-like form that is more than a stroke, constitutes a portion of the target character, can be a stand-alone character itself, can be a radical of another character but is not a radical of the target character (e.g., ± in , , , ; called a logographeme). Response times in the homogeneous blocks were significantly faster than those in the heterogeneous blocks (Experiment 5: 576 vs. 625, Experiment 6: 586 vs. 620). These results suggest a model of Chinese handwritten character production in which the stroke is not a functional unit, the radical plays the role of a morpheme, and the logographeme is the proximate unit. PMID:23950752

Chen, Jenn-Yeu; Cherng, Rong-Ju

2013-01-01

354

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

355

[Fibrocartilaginous mesenchymoma of the proximal humerus: case report].  

PubMed

Fibrocartilaginous mesenchymoma (FCM) is a rare tumor that primarily affects the long bones. Few cases have been reported since its description. A case of a 4-year-old boy with FCM located in the humerus is presented. Radiological examination showed an expansive lytic lesion located in the metaphyseal proximal humerus. Magnetic resonance imaging showed soft tissue expansion. Histopathological diagnosis was confirmatory of FCM. Curettage, adjuvant phenolization, and bone grafting with bone substitute, and autologous bone marrow was performed. During a follow-up period of 2 years, there was no evidence of disease progression. FCM should be considered in the differential diagnosis of lytic bone lesions in children and adolescents. PMID:25192540

Masquijo, Julio Javier; Sartori, Federico; Innocenti, Sergio

2014-10-01

356

[Fracture of a pyrolytic carbon proximal interphalangeal prosthesis: clinical case].  

PubMed

Pyrolytic carbon prostheses are one of the options for the treatment of arthritis of the proximal interphalangeal (PIP) joint. Deficiency of the extensor mechanism, instability, dislocation and infection are the most frequent causes described for revision. We report the case of a female patient who underwent a PIP arthroplasty with a pyrolytic carbon implant of her right long finger; she suffered from an implant fracture only 11 months after surgery, a rare complication of this kind of implant; it makes think to fragility of this kind of implant. PMID:24418023

Paulos, R-G; Sousa E Silva, R; Le Viet, D

2014-02-01

357

Proximal interphalangeal joint replacement: resurfacing pyrocarbon versus silicone arthroplasty.  

PubMed

Prosthetic replacement of the proximal interphalangeal joints is an operative treatment for osteoarhtritis, to preserve the range of motion and the function of the hand. The purpose of this study is to detect the differences regarding pain and function between a silicone implant using a volar approach and a resurfacing implant, placed through a dorsal approach. Patients were reviewed clinically and scored. We found no significant differences in outcome between the two types of implants. However, the complication rate in the resurfacing group was significantly higher. Also, the economic cost of both implants was significantly different. The resurfacing implants were more expensive than the silicone implants. PMID:25090791

Van Nuffel, Maarten; Degreef, Ilse; Willems, Sofie; De Smet, Luc

2014-06-01

358

Gap-optimized Moiré phase imaging alignment for proximity lithography  

NASA Astrophysics Data System (ADS)

The proposed four-quadrant Moiré alignment scheme to detect the misalignment between mask and wafer for proximity lithography can achieve the alignment accuracy with nanometer level. When implementing the scheme, however, the distribution of Moiré fringes associated with the mask-wafer gap indeed goes against the alignment, making the gap optimization highly urgent. The optimization model is established, and numerical simulation as well as experimental verification is also provided. Furthermore, an alignment accuracy of ˜3 nm with the illumination wavelength of 632.8 nm is experimentally attained. Simultaneously, the design mechanism of alignment marks for improving the availability of the alignment scheme is discussed.

Zhu, Jiangping; Hu, Song; You, Zhisheng; Su, Xianyu

2015-01-01

359

Cascading failures in networks with proximate dependent nodes.  

PubMed

We study the mutual percolation of a system composed of two interdependent random regular networks. We introduce a notion of distance to explore the effects of the proximity of interdependent nodes on the cascade of failures after an initial attack. We find a nontrivial relation between the nature of the transition through which the networks disintegrate and the parameters of the system, which are the degree of the nodes and the maximum distance between interdependent nodes. We explain this relation by solving the problem analytically for the relevant set of cases. In the process, we solve a variant of Rényi's parking problem on treelike graphs. PMID:24730900

Kornbluth, Yosef; Lowinger, Steven; Cwilich, Gabriel; Buldyrev, Sergey V

2014-03-01

360

Effect of handset proximity on hearing aid feedback.  

PubMed

The increased sensitivity of hearing aids to feedback as a telephone handset is brought near has been studied experimentally and numerically. For the measurements, three different hearing aids were modified so that the open-loop transfer function could be measured. They were mounted in the pinna of a mannikin and the change in open-loop transfer function determined as a function of handset proximity. Increases of over 20 dB were observed, most of this change occurring within the first 10 mm of separation between pinna and handset. Numerical calculations performed using a boundary element technique were in good agreement with the measurements. PMID:15058336

Stinson, Michael R; Daigle, Gilles A

2004-03-01

361

Effect of handset proximity on hearing aid feedback  

NASA Astrophysics Data System (ADS)

The increased sensitivity of hearing aids to feedback as a telephone handset is brought near has been studied experimentally and numerically. For the measurements, three different hearing aids were modified so that the open-loop transfer function could be measured. They were mounted in the pinna of a mannikin and the change in open-loop transfer function determined as a function of handset proximity. Increases of over 20 dB were observed, most of this change occurring within the first 10 mm of separation between pinna and handset. Numerical calculations performed using a boundary element technique were in good agreement with the measurements.

Stinson, Michael R.; Daigle, Gilles A.

2004-03-01

362

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.

Cohen, Lance

363

Distributed proximity sensor system having embedded light emitters and detectors  

NASA Technical Reports Server (NTRS)

A distributed proximity sensor system is provided with multiple photosensitive devices and light emitters embedded on the surface of a robot hand or other moving member in a geometric pattern. By distributing sensors and emitters capable of detecting distances and angles to points on the surface of an object from known points in the geometric pattern, information is obtained for achieving noncontacting shape and distance perception, i.e., for automatic determination of the object's shape, direction and distance, as well as the orientation of the object relative to the robot hand or other moving member.

Lee, Sukhan (Inventor)

1990-01-01

364

Osteochondroma Arising from the Proximal Fibula: A Rare Presentation  

PubMed Central

Osteochondromas are commonly encountered benign tumours and they are characterized by cartilage capped bony growths that project from the surface of the affected bone. Osteochondromas tend to grow eccentrically rather than centrifugally. We are reporting a case of an 18-year-old male, who had presentation of a large, hard, irregular swelling over anterolateral aspect of his right leg. There was no neurovascular deficit in the extremity. Computed tomography showed that the origin of the tumour was probably proximal fibula. En-block excision of mass was done. A histopathological examination confirmed the diagnosis of a benign osteochondroma. Patient had uneventful recovery without any evidence of recurrence. PMID:24959469

Malgonde, Monika; Jain, Pramod

2014-01-01

365

Ground plane insulating coating for proximity focused devices  

DOEpatents

A thin layer of alumina (aluminum oxide) is coated onto the ground plane of a microchannel plate (MCP) without covering the pores of the MCP so it does not effect the performance. The coating is sputtered onto the ground plane at a very steep angle. The addition of the thin dielectric coating of alumina greatly improves the spatial resolution of proximity focused image intensifiers using a narrow gap between the phosphor screen and the MCP. With the coating on the ground plane and the same gap the phosphor screen can be ran at 9000 volts, as compared to 3 kV without the coating. 3 figs.

Power, G.D.

1998-07-14

366

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

367

Late proximal coronary artery stenosis complicating percutaneous endovascular catheterisation procedures  

Microsoft Academic Search

Background  Late-onset proximal coronary artery stenosis caused by preceding percutaneous catheterisation procedures remains under-surveyed.\\u000a \\u000a \\u000a \\u000a Methods  From 1993, all patients undergoing percutaneous coronary procedures and a second session within 3 years were included except\\u000a those ever treated by coronary bypass surgery or chest radiotherapy during this 3-year period. Emergence of a new lesion or\\u000a worsening of an initially insignificant lesion to >50% of diameter

H.-C. Lai; W.-L. Lee; K.-Y. Wang; C.-T. Ting; C.-S. Su; T.-J. Liu

368

Ground plane insulating coating for proximity focused devices  

DOEpatents

A thin layer of alumina (aluminum oxide) is coated onto the ground plane of a microchannel plate (MCP) without covering the pores of the MCP so it does not effect the performance. The coating is sputtered onto the ground plane at a very steep angle. The addition of the thin dielectric coating of alumina greatly improves the spatial resolution of proximity focused image intensifiers using a narrow gap between the phosphor screen and the MCP. With the coating on the ground plane and the same gap the phosphor screen can be ran at 9000 volts, as compared to 3 kV without the coating.

Power, Gary D. (Manteca, CA)

1998-01-01

369

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

370

NaF Documentation  

Cancer.gov

The NaF documentation files are presented in Adobe Acrobat or Word files. PDF Generic Documentation for NaF PDF file Word Generic Documentation for NaFWord file Contact Paula M. Jacobs, Ph.D., 301-435-9181, jacobsp@mail.nih.gov, for information. Print

371

Proximity to Pollution Sources and Risk of Amphibian Limb Malformation  

PubMed Central

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.

2005-01-01

372

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. PMID:7140691

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

1982-01-01

373

Probing nuclear pore complex architecture with proximity-dependent biotinylation  

PubMed Central

Proximity-dependent biotin identification (BioID) is a method for identifying protein associations that occur in vivo. By fusing a promiscuous biotin ligase to a protein of interest expressed in living cells, BioID permits the labeling of proximate proteins during a defined labeling period. In this study we used BioID to study the human nuclear pore complex (NPC), one of the largest macromolecular assemblies in eukaryotes. Anchored within the nuclear envelope, NPCs mediate the nucleocytoplasmic trafficking of numerous cellular components. We applied BioID to constituents of the Nup107–160 complex and the Nup93 complex, two conserved NPC subcomplexes. A strikingly different set of NPC constituents was detected depending on the position of these BioID-fusion proteins within the NPC. By applying BioID to several constituents located throughout the extremely stable Nup107–160 subcomplex, we refined our understanding of this highly conserved subcomplex, in part by demonstrating a direct interaction of Nup43 with Nup85. Furthermore, by using the extremely stable Nup107–160 structure as a molecular ruler, we defined the practical labeling radius of BioID. These studies further our understanding of human NPC organization and demonstrate that BioID is a valuable tool for exploring the constituency and organization of large protein assemblies in living cells. PMID:24927568

Kim, Dae In; KC, Birendra; Zhu, Wenhong; Motamedchaboki, Khatereh; Doye, Valérie; Roux, Kyle J.

2014-01-01

374

Proximity effect in MgB2-Permalloy hybrid system  

NASA Astrophysics Data System (ADS)

Recently ferromagnet/superconductor systems have attracted a great attention due to their scientific interest and potential for the technological application. So far, most of the work has been done for Nb with ferromagnetic metals or high temperature oxide superconductors with magnetic oxides. In this presentation we will discuss the proximity effect in magnesium diboride (MgB2)/Py thin films, where the superconducting property changes due to the adjacent Py layer. Even though the good electronic properties such as large critical current density and large coherence length of MgB2 make it a good candidate for superconducting electronic applications, depositing a good-quality in-situ MgB2 thin film is still challenging. Especially for the multilayer deposition, it is ideal to deposit all the layers in-situ without ex-situ treatment. We used a sputtering to deposit the MgB2 layer in-situ and made a hybrid system with Py. We found that the substrate temperature during the MgB2 deposition is the most important parameter to determine the superconducting transition temperature of the sample. In addition to the proximity effect we will also discuss the problem with a sputtering method for MgB2 deposition.

O'Brien, April; Gu, Jiyeong

2008-03-01

375

Method to measure tone of axial and proximal muscle.  

PubMed

The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. PMID:22214974

Gurfinkel, Victor S; Cacciatore, Timothy W; Cordo, Paul J; Horak, Fay B

2011-01-01

376

The effect of proximity on landmark use in Clark's nutcrackers.  

PubMed

Clark's nutcrackers, Nucifraga columbiana, store thousands of pine seeds during the autumn and retrieve them throughout the winter. It has been shown that these birds are able to use visual cues to relocate hidden food in the laboratory. In this set of experiments, we trained three groups of Clark's nutcrackers to find a hidden food goal that was placed in the same spatial location relative to the testing room. During training, the location of two local cues in relation to the goal differed between the three groups. Group 1 learned the task with the cues closest to the goal, group 2 with the cues further from the goal, and group 3 with the cues furthest from the goal. To test whether the proximity of these two local cues to the goal affected how spatial information was used, we manipulated local and global information in a series of experiments. Results indicated that local cues were more important sources of spatial information for group 1, whereas global cues seemed to be used more by birds in groups 2 and 3. These findings suggest that the proximity of visual cues lead to overshadowing of other sources of spatial information surrounding the goal. Copyright 1999 The Association for the Study of Animal Behaviour. PMID:10479363

Gould-Beierle; Kamil

1999-09-01

377

Modulation of hydrophobic interactions by proximally immobilized ions.  

PubMed

The structure of water near non-polar molecular fragments or surfaces mediates the hydrophobic interactions that underlie a broad range of interfacial, colloidal and biophysical phenomena. Substantial progress over the past decade has improved our understanding of hydrophobic interactions in simple model systems, but most biologically and technologically relevant structures contain non-polar domains in close proximity to polar and charged functional groups. Theories and simulations exploring such nanometre-scale chemical heterogeneity find it can have an important effect, but the influence of this heterogeneity on hydrophobic interactions has not been tested experimentally. Here we report chemical force microscopy measurements on alkyl-functionalized surfaces that reveal a dramatic change in the surfaces' hydrophobic interaction strengths on co-immobilization of amine or guanidine groups. Protonation of amine groups doubles the strength of hydrophobic interactions, and guanidinium groups eliminate measurable hydrophobic interactions in all pH ranges investigated. We see these divergent effects of proximally immobilized cations also in single-molecule measurements on conformationally stable ?-peptides with non-polar subunits located one nanometre from either amine- or guanidine-bearing subunits. Our results demonstrate the importance of nanometre-scale chemical heterogeneity, with hydrophobicity not an intrinsic property of any given non-polar domain but strongly modulated by functional groups located as far away as one nanometre. The judicious placing of charged groups near hydrophobic domains thus provides a strategy for tuning hydrophobic driving forces to optimize molecular recognition or self-assembly processes. PMID:25592540

Ma, C Derek; Wang, Chenxuan; Acevedo-Vélez, Claribel; Gellman, Samuel H; Abbott, Nicholas L

2015-01-15

378

Scattering effects in proximity-effect tunneling spectroscopy  

SciTech Connect

The PETS (Proximity Effect Tunneling Spectroscopy) technique was applied to niobium/yttrium and niobium/lutetium bilayers. The electron - phonon interaction parameter lambda/sub e-ph/ is 0.55 for yttrium and 0.67 for lutetium. The spin-fluctuations parameters lambda/sub S/ is 0.20 for yttrium and 0.33 for lutetium. It was found that the large spin fluctuation in yttrium and lutetium have responsibility for the absence of superconductivity in them. The results have given a reasonable explanation of high superconducting transition temperature in them under high pressure. The large reflection coefficient and strong diffuse scattering at the Nb/Y and Nb/Lu interfaces was discovered, and it should have strong influence on the transport properties of metallic superlattices. From the modeling study of elastic scattering in proximity-effect tunnel junctions, the author explains why some conventional made high T/sub C/ superconducting tunnel junctions give ideal-like characteristics in the gap region, but variable-strength phonon structures in the phonon region.

Gai, W.

1987-01-01

379

A positioned +1 nucleosome enhances promoter-proximal pausing  

PubMed Central

Chromatin distribution is not uniform along the human genome. In most genes there is a promoter-associated nucleosome free region (NFR) followed by an array of nucleosomes towards the gene body in which the first (+1) nucleosome is strongly positioned. The function of this characteristic chromatin distribution in transcription is not fully understood. Here we show in vivo that the +1 nucleosome plays a role in modulating RNA polymerase II (RNAPII) promoter-proximal pausing. When a +1 nucleosome is strongly positioned, elongating RNAPII has a tendency to stall at the promoter-proximal region, recruits more negative elongation factor (NELF) and produces less mRNA. The nucleosome-induced pause favors pre-mRNA quality control by promoting the addition of the cap to the nascent RNA. Moreover, the uncapped RNAs produced in the absence of a positioned nucleosome are degraded by the 5?-3? exonuclease XRN2. Interestingly, reducing the levels of the chromatin remodeler ISWI factor SNF2H decreases +1 nucleosome positioning and increases RNAPII pause release. This work demonstrates a function for +1 nucleosome in regulation of transcription elongation, pre-mRNA processing and gene expression. PMID:25735750

Jimeno-González, Silvia; Ceballos-Chávez, María; Reyes, José C.

2015-01-01

380

Promoter-proximal polyadenylation sites reduce transcription activity  

PubMed Central

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

2012-01-01

381

Orion Handling Qualities During ISS Proximity Operations and Docking  

NASA Technical Reports Server (NTRS)

NASA's Orion spacecraft is designed to autonomously rendezvous and dock with many vehicles including the International Space Station. However, the crew is able to assume manual control of the vehicle s attitude and flight path. In these instances, Orion must meet handling qualities requirements established by NASA. Two handling qualities assessments were conducted at the Johnson Space Center to evaluate preliminary designs of the vehicle using a six degree of freedom, high-fidelity guidance, navigation, and control simulation. The first assessed Orion s handling qualities during the last 20 ft before docking, and included both steady and oscillatory motions of the docking target. The second focused on manual acquisition of the docking axis during the proximity operations phase and subsequent station-keeping. Cooper-Harper handling qualities ratings, workload ratings and comments were provided by 10 evaluation pilots for the docking study and 5 evaluation pilots for the proximity operations study. For the docking task, both cases received 90% Level 1 (satisfactory) handling qualities ratings, exceeding NASA s requirement. All ratings for the ProxOps task were Level 1. These evaluations indicate that Orion is on course to meet NASA's handling quality requirements for ProxOps and docking.

Stephens, John-Paul; Vos, Gordon A.; Bilimoria, Karl D.; Mueller, Eric R.; Brazzel, Jack; Spehar, Pete

2011-01-01

382

Modulation of hydrophobic interactions by proximally immobilized ions  

NASA Astrophysics Data System (ADS)

The structure of water near non-polar molecular fragments or surfaces mediates the hydrophobic interactions that underlie a broad range of interfacial, colloidal and biophysical phenomena. Substantial progress over the past decade has improved our understanding of hydrophobic interactions in simple model systems, but most biologically and technologically relevant structures contain non-polar domains in close proximity to polar and charged functional groups. Theories and simulations exploring such nanometre-scale chemical heterogeneity find it can have an important effect, but the influence of this heterogeneity on hydrophobic interactions has not been tested experimentally. Here we report chemical force microscopy measurements on alkyl-functionalized surfaces that reveal a dramatic change in the surfaces' hydrophobic interaction strengths on co-immobilization of amine or guanidine groups. Protonation of amine groups doubles the strength of hydrophobic interactions, and guanidinium groups eliminate measurable hydrophobic interactions in all pH ranges investigated. We see these divergent effects of proximally immobilized cations also in single-molecule measurements on conformationally stable ?-peptides with non-polar subunits located one nanometre from either amine- or guanidine-bearing subunits. Our results demonstrate the importance of nanometre-scale chemical heterogeneity, with hydrophobicity not an intrinsic property of any given non-polar domain but strongly modulated by functional groups located as far away as one nanometre. The judicious placing of charged groups near hydrophobic domains thus provides a strategy for tuning hydrophobic driving forces to optimize molecular recognition or self-assembly processes.

Ma, C. Derek; Wang, Chenxuan; Acevedo-Vélez, Claribel; Gellman, Samuel H.; Abbott, Nicholas L.

2015-01-01

383

Influence of the proximity effect on SRM 768  

NASA Astrophysics Data System (ADS)

In order to suppress supercooling of the superconductive transitions of the W (Tc 15.5 mK) and Be (Tc 23 mK) samples incorporated in SRM 768, we have attached a higher Tc material (aluminum) to them. Although successful, the Al induces a diamagnetism above the bulk transition temperature of the two materials. We have studied the influence of this proximity effect on the superconducting properties to better define the transition temperature. We have applied the Ginzburg-Landau equations to calculate the behavior of the diamagnetism of macroscopic samples consisting of a normal metal in contact with a superconductor. We have compared these calculations with experimental measurements of the temperature ( 0.006 K to 1 K) and magnetic field (10-9 to 10-6 T) dependence of the diamagnetism for several samples of Be and W. The agreement between the predictions and measurement is quite good and confirms the approach of using the Ginzburg-Landau model to calculate the proximity effect in macroscopic normal systems above their superconductive transitions. This understanding can be used to better define the bulk transition temperature.

Soulen, Robert

1997-04-01

384

Restoring proximal caries lesions conservatively with tunnel restorations  

PubMed Central

The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations. PMID:24019754

Chu, Chun-Hung; Mei, May L; Cheung, Chloe; Nalliah, Romesh P

2013-01-01

385

Proximity effect in superconductor/conical magnet/ferromagnet heterostructures  

NASA Astrophysics Data System (ADS)

At the interface between a superconductor and a ferromagnetic metal spin-singlet Cooper pairs can penetrate into the ferromagnetic part of the heterostructure with an oscillating and decaying spin-singlet Cooper pair density. However, if the interface allows for a spin-mixing effect, equal-spin spin-triplet Cooper pairs can be generated that can penetrate much further into the ferromagnetic part of the heterostructure, known as the long-range proximity effect. Here, we present results of spin-mixing based on self-consistent solutions of the microscopic Bogoliubov-de Gennes equations in the clean limit incorporating a tight-binding model. In particular, we include a conical magnet into our model heterostructure to generate the spin-triplet Cooper pairs and analyse the influence of conical and ferromagnetic layer thickness on the unequal-spin and equal-spin spin-triplet pairing correlations. It will be shown that, in agreement with experimental observations, a minimum thickness of the conical magnet is necessary to generate a sufficient amount of equal-spin spin-triplet Cooper pairs allowing for the long-range proximity effect.

Fritsch, Daniel; Annett, James F.

2014-05-01

386

Proximate Composition, Amino Acid, Mineral, and Heavy Metal Content of Dried Laver  

PubMed Central

Laver, a red algae belonging to the genus Porphyra, is one of the most widely consumed edible seaweeds. The most popular commercial dried laver species, P. tenera and P. haitanensis, were collected from Korea and China, respectively, and evaluated for proximate composition, amino acids, minerals, trace heavy metals, and color. The moisture and ash contents of P. tenera and P. haitanensis ranged from 3.66~6.74% and 8.78~9.07%, respectively; crude lipid and protein contents were 1.96~2.25% and 32.16~36.88%, respectively. Dried lavers were found to be a good source of amino acids, such as asparagine, isoleucine, leucine, and taurine, and ?-aminobutyric acid. K, Ca, Mg, Na, P, I, Fe, and Se minerals were selected for analysis. A clear regional variation existed in the amino acid, mineral, and trace metal contents of lavers. Regular consumption of lavers may have heath benefits because they are relatively low in fat and high in protein, and contain functional amino acids and minerals. PMID:24471123

Hwang, Eun-Sun; Ki, Kyung-Nam; Chung, Ha-Yull

2013-01-01

387

Acute mannitol and saline volume expansion in the rat: effect on transepithelial potential difference in proximal tubules.  

PubMed

1. Transepithelial potential difference (PDte) of proximal tubules was measured in rats under control conditions (C), and mannitol-saline and saline extracellular fluid volume expansion (MVE, SVE, respectively) under conditions of normal net lumen to basal sodium transport. 2. PDte was measured in kidneys bathed with Hartmann's solution or covered with mineral oil under both volume-expanded conditions together with their controls. 3. PDte was significantly lower in kidneys bathed with Hartmann's solution than those covered with oil. 4. In MVE rats, with mineral oil covering the kidneys, PDte (expressed as mean and s.e.m.) was for the control 2.20 +/- 0.05 (n = 45) mV and MVE 1.97 +/- 0.04 (n = 36) mV, lumen positive, a significant reduction of 10% (P less than 0.001). In SVE rats, with mineral oil covering the kidneys, PDte was for C = 2.42 +/- 0.05 (n = 74) mV and SVE = 1.93 +/- 0.03 (n = 67) mV, a significant reduction (P less than 0.001) of 20%. 5. According to thermodynamic considerations, neither of these changes is sufficient to explain the 50% inhibition of Na transport measured previously during MVE and SVE with autologous tubular fluid. The present results offer further evidence supporting the idea that the inhibition of Na transport during MVE and SVE is largely due to inhibition of the active Na transporting step. PMID:2112434

Sugo, E; Györy, A Z

1990-01-01

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. PMID:22317977

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

Quantum control of proximal spins using nanoscale magnetic resonance imaging  

E-print Network

Quantum control of individual spins in condensed matter systems is an emerging field with wide-ranging applications in spintronics, quantum computation, and sensitive magnetometry. Recent experiments have demonstrated the ability to address and manipulate single electron spins through either optical or electrical techniques. However, it is a challenge to extend individual spin control to nanoscale multi-electron systems, as individual spins are often irresolvable with existing methods. Here we demonstrate that coherent individual spin control can be achieved with few-nm resolution for proximal electron spins by performing single-spin magnetic resonance imaging (MRI), which is realized via a scanning magnetic field gradient that is both strong enough to achieve nanometric spatial resolution and sufficiently stable for coherent spin manipulations. We apply this scanning field-gradient MRI technique to electronic spins in nitrogen-vacancy (NV) centers in diamond and achieve nanometric resolution in imaging, char...

Grinolds, M S; Hong, S; Lukin, M D; Walsworth, R L; Yacoby, A

2011-01-01

390

Transition Metal Dichalcogenide Growth via Close Proximity Precursor Supply  

PubMed Central

Reliable chemical vapour deposition (CVD) of transition metal dichalcogenides (TMDs) is currently a highly pressing research field, as numerous potential applications rely on the production of high quality films on a macroscopic scale. Here, we show the use of liquid phase exfoliated nanosheets and patterned sputter deposited layers as solid precursors for chemical vapour deposition. TMD monolayers were realized using a close proximity precursor supply in a CVD microreactor setup. A model describing the growth mechanism, which is capable of producing TMD monolayers on arbitrary substrates, is presented. Raman spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, atomic force microscopy, transmission electron microscopy, scanning electron microscopy and electrical transport measurements reveal the high quality of the TMD samples produced. Furthermore, through patterning of the precursor supply, we achieve patterned growth of monolayer TMDs in defined locations, which could be adapted for the facile production of electronic device components. PMID:25487822

O'Brien, Maria; McEvoy, Niall; Hallam, Toby; Kim, Hye-Young; Berner, Nina C.; Hanlon, Damien; Lee, Kangho; Coleman, Jonathan N.; Duesberg, Georg S.

2014-01-01

391

Complications following dislocations of the proximal interphalangeal joint.  

PubMed

Dorsal fracture-dislocations of the proximal interphalangeal joint are challenging injuries to treat and are associated with many complications. The determination of stability is crucial to appropriate management. Stable injuries can usually be treated nonsurgically, whereas unstable injuries typically require surgical stabilization. Many surgical techniques have been used, including extension block pinning, volar plate arthroplasty, open reduction and internal fixation, external fixation, and hemihamate autografting. Because stiffness and flexion contracture are frequent complications, every effort should be made to initiate early motion while maintaining concentric reduction. Other complications include redislocation, chronic swelling, swan neck and coronal plane deformities, and pin tract infections. Assessing injury characteristics, including chronicity, the percentage of articular surface fractured, and the degree of comminution, and understanding complications will help in determining the most appropriate treatment. Chronic dislocations and those injuries in which painful arthritis develops can be successfully treated with salvage procedures, including arthroplasty and arthrodesis. PMID:24720300

Mangelson, John J; Stern, Peter J; Abzug, Joshua M; Chang, James; Osterman, A Lee

2014-01-01

392

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

393

Probing dynamic protein ensembles with atomic proximity measures.  

PubMed

The emerging role of internal dynamics in protein fold and function requires new avenues of structure analysis. We analyzed the dynamically restrained conformational ensemble of ubiquitin generated from residual dipolar coupling data, in terms of protruding and buried atoms as well as interatomic distances, using four proximity-based algorithms, CX, DPX, PRIDE and PRIDE-NMR (http://hydra.icgeb.trieste.it/protein/). We found that Ubiquitin, this relatively rigid molecule has a highly diverse dynamic ensemble. The environment of protruding atoms is highly variable across conformers, on the other hand, only a part of buried atoms tends to fluctuate. The variability of the ensemble cautions against the use of single conformers when explaining functional phenomena. We also give a detailed evaluation of PRIDE-NMR on a wide dataset and discuss its usage in the light of the features of available NMR distance restraint sets in public databases. PMID:20887264

Gáspári, Zoltán; Angyán, Annamária F; Dhir, Somdutta; Franklin, Dino; Perczel, András; Pintar, Alessandro; Pongor, Sándor

2010-11-01

394

Graphene spintronics: Spin injection and proximity effects from first principles  

NASA Astrophysics Data System (ADS)

Ferromagnet/graphene (F/Gr) junctions are important building blocks for graphene spintronics. While simple models of spin injection are very successful for macroscopic metallic junctions, they reveal many deficiencies in describing F/Gr junctions. First-principles methods are key to assess such Gr-based junctions, but the computational cost is often too high. We focus on Ni(111)/Gr junctions and include van der Waals interactions from first principles, crucial for their correct description. We formulate a computationally inexpensive model to examine the nonuniformity and bias dependence of spin injection and elucidate proximity effects using spin polarization maps. Our results could extend the applicability of simple spin injection models in F/Gr junctions.

Lazi?, P.; Sipahi, G. M.; Kawakami, R. K.; Žuti?, Igor

2014-08-01

395

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

396

[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

397

Magnetoresistance in bilayer graphene via ferromagnet proximity effects  

NASA Astrophysics Data System (ADS)

A drastic modification of electronic band structure is predicted in bilayer graphene when it is placed between two ferromagnetic insulators. Due to the exchange interaction with the proximate ferromagnet, the electronic energy dispersion in the graphene channel strongly depends on the magnetization orientation of two ferromagnetic layers, M1 and M2 . While the parallel configuration M1=M2 leads to simple spin splitting of both conduction and valence bands, an energy gap is induced as soon as the angle ? between M1 and M2 becomes nonzero with the maximum achieved at ?=? (i.e., antiparallel alignment). Consequently, bilayer graphene may exhibit a sizable magnetoresistance effect in the current-in-plane configuration. A rough estimate suggests that the resistance changes on the order of tens of percent is possible at room temperature. This effect is expected to become more pronounced as the temperatures decreases.

Semenov, Y. G.; Zavada, J. M.; Kim, K. W.

2008-06-01

398

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

399

Osteomyelitis of the pelvis and proximal femur: diagnostic difficulties.  

PubMed

Osteomyelitis of the pelvis or proximal femur may still be diagnosed late because the infection is deeply placed and investigations may concentrate solely upon the possibility of septic arthritis. Periacetabular infection was diagnosed in 16 children between 1994 and 1998. A high index of suspicion and the use of appropriate imaging will ensure that the condition is not allowed to progress, although in this series one child underwent an unnecessary appendectomy, and a subsequent sepsis of the hip joint was drained in another case. Radiographs of the pelvis were rarely abnormal within 7 days of the onset of symptoms and an ultrasound scan focused on the hip joint may miss the periarticular changes. PMID:11360776

Hammond, P J; Macnicol, M F

2001-04-01

400

Orion Rendezvous, Proximity Operations, and Docking Design and Analysis  

NASA Technical Reports Server (NTRS)

The Orion vehicle will be required to perform rendezvous, proximity operations, and docking with the International Space Station (ISS) and the Earth Departure Stage (EDS)/Lunar Landing Vehicle (LLV) stack in Low Earth Orbit (LEO) as well as with the Lunar Landing Vehicle in Low Lunar Orbit (LLO). The RPOD system, which consists of sensors, actuators, and software is being designed to be flexible and robust enough to perform RPOD with different vehicles in different environments. This paper will describe the design and the analysis which has been performed to date to allow the vehicle to perform its mission. Since the RPOD design touches on many areas such as sensors selection and placement, trajectory design, navigation performance, and effector performance, it is inherently a systems design problem. This paper will address each of these issues in order to demonstrate how the Orion RPOD has been designed to accommodate and meet all the requirements levied on the system.

D'Souza, Christopher; Hanak, F. Chad; Spehar, Pete; Clark, Fred D.; Jackson, Mark

2007-01-01

401

Rendezvous, proximity operations and capture quality function deployment report  

NASA Technical Reports Server (NTRS)

Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

Lamkin, Stephen L. (editor)

1991-01-01

402

Retroperitoneal Laparoscopic Ureterolithotomy for Proximal Ureteral Calculi in Selected Patients  

PubMed Central

Objectives. To summarize our experience of retroperitoneal laparoscopic ureterolithotomy for ureteral calculi and evaluate the safety and efficiency of this procedure. Methods. We conducted a retrospective analysis of 197 patients with proximal ureteral calculi who accepted retroperitoneal laparoscopic ureterolithotomy from June 2005 to June 2014. Results. All procedures were performed successfully and the mean operating time and estimated blood loss were 87?min and 64?mL. The clearance rate was 98.5% and the rates of urine leak and ureteral stricture were 2.5% and 1.0%. Conclusions. Retroperitoneal laparoscopic ureterolithotomy is a safe and effective procedure for patients with complex stones or anatomic abnormalities, and, with experience of high volume series, it is also a reasonable choice as the primary treatment for such selected patients. PMID:25548791

Hu, Qingfeng; Ding, Weihong; Gou, Yuancheng; Ho, Yatfaat; Xu, Ke; Gu, Bin; Sun, Chuanyu; Xia, Guowei; Ding, Qiang

2014-01-01

403

Fracture-dislocations of the proximal interphalangeal joint.  

PubMed

Fracture-dislocations of the proximal interphalangeal joint encompass a spectrum of injury severity, ranging from injuries that require little intervention to those that require advanced reconstructive surgery for optimal outcome. Three fracture-dislocation patterns are recognized: dorsal, volar, and pilon. Acceptable outcome is dependent on achieving and maintaining a well-aligned and well-reduced joint, re-establishing normal joint kinematics, and restoring motion. Anatomic articular surface reduction is desirable but not absolutely necessary for a good outcome. Treatment depends on both the type of injury and patient-dependent factors. Optimal outcome for a specific injury is predicated on expedient diagnosis and recognition of injury severity, which enables initiation of appropriate management. PMID:23378372

Elfar, John; Mann, Tobias

2013-02-01

404

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

405

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

406

Visualizing cell proximity with genetically encoded bioluminescent reporters.  

PubMed

Cell-cell interactions underlie diverse physiological processes ranging from immune function to cell migration. Dysregulated cellular crosstalk also potentiates numerous pathologies, including infections and metastases. Despite their ubiquity in organismal biology, cell-cell interactions are difficult to examine in tissues and whole animals without invasive procedures. Here, we report a strategy to noninvasively image cell proximity using engineered bioluminescent probes. These tools comprise "split" fragments of Gaussia luciferase (Gluc) fused to the leucine zipper domains of Fos and Jun. When cells secreting the fragments draw near one another, Fos and Jun drive the assembly of functional, light-emitting Gluc. Photon production thus provides a readout on the distance between two cell types. We used the split fragments to visualize cell-cell interactions over time in vitro and in macroscopic models of cell migration. Further application of these tools in live organisms will refine our understanding of cell contacts relevant to basic biology and disease. PMID:25643167

Jones, Krysten A; Li, David J; Hui, Elliot; Sellmyer, Mark A; Prescher, Jennifer A

2015-04-17

407

Tests of a proximity focusing RICH with aerogel as radiator  

E-print Network

Using aerogel as radiator and multianode PMTs for photon detection, a proximity focusing Cherenkov ring imaging detector has been constructed and tested in the KEK $\\pi$2 beam. The aim is to experimentally study the basic parameters such as resolution of the single photon Cherenkov angle and number of detected photons per ring. The resolution obtained is well approximated by estimates of contributions from pixel size and emission point uncertainty. The number of detected photons per Cherenkov ring is in good agreement with estimates based on aerogel and detector characteristics. The values obtained turn out to be rather low, mainly due to Rayleigh scattering and to the relatively large dead space between the photocathodes. A light collection system or a higher fraction of the photomultiplier active area, together with better quality aerogels are expected to improve the situation. The reduction of Cherenkov yield, for charged particle impact in the vicinity of the aerogel tile side wall, has also been measured.

I. Adachi; I. Bizjak; A. Gorisek; T. Iijima; M. Iwamoto; S. Korpar; P. Krizan; R. Pestotnik; M. Staric; A. Stanovnik; T. Sumiyoshi; K. Suzuki; T. Tabata

2003-03-25

408

Residential Proximity to Environmental Hazards and Adverse Health Outcomes  

PubMed Central

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

Maantay, Juliana A.; Chakraborty, Jayajit

2011-01-01

409

Transition Metal Dichalcogenide Growth via Close Proximity Precursor Supply  

NASA Astrophysics Data System (ADS)

Reliable chemical vapour deposition (CVD) of transition metal dichalcogenides (TMDs) is currently a highly pressing research field, as numerous potential applications rely on the production of high quality films on a macroscopic scale. Here, we show the use of liquid phase exfoliated nanosheets and patterned sputter deposited layers as solid precursors for chemical vapour deposition. TMD monolayers were realized using a close proximity precursor supply in a CVD microreactor setup. A model describing the growth mechanism, which is capable of producing TMD monolayers on arbitrary substrates, is presented. Raman spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, atomic force microscopy, transmission electron microscopy, scanning electron microscopy and electrical transport measurements reveal the high quality of the TMD samples produced. Furthermore, through patterning of the precursor supply, we achieve patterned growth of monolayer TMDs in defined locations, which could be adapted for the facile production of electronic device components.

O'Brien, Maria; McEvoy, Niall; Hallam, Toby; Kim, Hye-Young; Berner, Nina C.; Hanlon, Damien; Lee, Kangho; Coleman, Jonathan N.; Duesberg, Georg S.

2014-12-01

410

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

411

Extraction of spatial proximity patterns by concept generalization  

SciTech Connect

We study the spatial data mining problem of how to extract a special type of proximity relationship-namely that of distinguishing two clusters of points based on the types of their neighboring features. The points in the clusters may represent houses on a map, and the features may represent spatial entities such as schools, parks, golf courses, etc. Classes of features are organized into concept hierarchies. We develop algorithm GenDis which uses concept generalization to identify the distinguishing features or concepts which serve as discriminators. Furthermore, we study the issue of which discriminators are {open_quotes}better{close_quotes} than others by introducing the notion of maximal discriminators, and by using a ranking system to quantitatively weigh maximal discriminators from different concept hierarchies.

Knorr, E.M.; Ng, R.T. [Univ. of British Columbia, Vancouver (Canada)

1996-12-31

412

Fundamental proximity effects in focused electron beam induced deposition.  

PubMed

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. PMID:22181556

Plank, Harald; Smith, Daryl A; Haber, Thomas; Rack, Philip D; Hofer, Ferdinand

2012-01-24

413

Shockwave Therapy for the Treatment of Chronic Proximal Hamstring Tendinopathy in Professional Athletes  

Microsoft Academic Search

Background: Chronic proximal hamstring tendinopathy is an overuse syndrome that is usually managed by nonoperative methods. Shockwave therapy has proved to be effective in many tendinopathies.Hypothesis: Shockwave therapy may be more effective than other nonoperative treatments for chronic proximal hamstring tendinopathy.Study Design: Randomized controlled clinical study; Level of evidence, 1.Methods: Forty professional athletes with chronic proximal hamstring tendinopathy were enrolled

Angelo Cacchio; Jan D. Rompe; John P. Furia; Piero Susi; Valter Santilli; Fosco De Paulis

2011-01-01

414

A proximal point algorithm for the monotone second-order cone complementarity problem  

Microsoft Academic Search

This paper is devoted to the study of the proximal point algorithm for solving monotone second-order cone complementarity\\u000a problems. The proximal point algorithm is to generate a sequence by solving subproblems that are regularizations of the original\\u000a problem. After given an appropriate criterion for approximate solutions of subproblems by adopting a merit function, the proximal\\u000a point algorithm is verified to

Jia Wu; Jein-Shan Chen

2012-01-01

415

Proximal minimizations with D -functions and the massively parallel solution of linear network programs  

Microsoft Academic Search

This paper discusses the massively parallel solution of linear network programs. It integrates the general algorithmic framework of proximal minimization with D-functions (PMD) with primal-dual row-action algorithms. Three alternative algorithmic schemes are studied: quadratic proximal point, entropic proximal point, and least 2-norm perturbations. Each is solving a linear network problem by solving a sequence of nonlinear approximations. The nonlinear subproblems

Soren S. Nielsen; Stavros A. Zenios

1993-01-01

416

Best proximity point theorems for cyclic orbital Meir–Keeler contraction maps  

Microsoft Academic Search

We introduce a notion of cyclic orbital Meir–Keeler contraction and give sufficient conditions for the existence of fixed points and best proximity points of such a map. Our main result is a generalization of a best proximity point result due to Di Bari et al. [C. Di Bari, T. Suzuki, C. Vetro, Best proximity points for cyclic Meir–Keeler contractions, Nonlinear Anal.

S. Karpagam; Sushama Agrawal

2011-01-01

417

Monocyclic and dicyclic hydrocarbons: structural requirements for proximal giant axonopathy.  

PubMed

The chromogenic and neurotoxic gamma-diketone 1,2-diacetylbenzene (1,2-DAB), but not its isomer 1,3-DAB, induces blue discoloration of tissues and urine, clustering of axonal microtubules and proximal neurofilament-filled axonal swellings in rodents. The remarkable chromogenic property of 1,2-DAB, a monocyclic aromatic hydrocarbon, arises from reaction with lysine residues of proteins and formation of dimeric and polymeric derivatives. Tetralin, a dicyclic solvent structurally related to acetyl ethyl tetramethyl tetralin, a chromogenic and neurotoxic agent, reportedly induces excretion of green urine, and causes neurological disturbances in humans. Monocyclic aromatic 1,2,4-triethylbenzene (1,2,4-TEB), but not its isomer 1,3,5-TEB, is also reportedly chromogenic and induces neurophysiological deficits in rodents consistent with axonal neuropathy, but without neuropathological confirmation. We treated 12-week-old C57Bl/6 mice by gavage with 300, 600, or 900 mg/kg/day 1,2,4-TEB, or equivalent doses of 1,3,5-TEB, 3 days/week, for up to 12 weeks, or intraperitoneally with 400 mg/kg/day tetralin, or 50 or 100 mg/kg/day of its alpha-tetralol analogue, 5 days/week, for up to 5 weeks. Animals treated with 1,2,4-TEB, but not 1,3,5-TEB, tetralin or alpha-tetralol, developed hind limb weakness, excreted greenish urine, and showed 1,2-DAB-like neuropathology. These findings support the hypothesis that 1,2-spaced ethyl (or acetyl) moieties on a benzene ring of hydrocarbons are required for hydrocarbons to induce chromogenic changes and proximal giant neurofilamentous axonopathy. Key molecular targets of these compounds likely reside in the axon where they serve to maintain normal cytoskeletal organization. PMID:16874529

Tshala-Katumbay, Desire D; Palmer, Valerie S; Lasarev, Michael R; Kayton, Robert J; Sabri, Mohammad I; Spencer, Peter S

2006-09-01

418

Feasibility and Outcome of Proximal Catheter Ileostomy – A Pilot Study  

PubMed Central

Background/Aim: Loop ileostomy has high complication rates and causes much patient inconvenience. This study was carried out to evaluate the feasibility and outcome of a proximal catheter ileostomy in place of loop ileostomy in patients treated by intestinal repair and/or resection-anastomosis.Design: Prospective study.Setting: J. N. Medical College Hospital, Aligarh Muslim University, Aligarh, India. Patients and Methods: From November 2006 to November 2009, in all patients treated surgically by primary repair and/or resection-anastomosis of small and/or large bowel, we constructed a catheter ileostomy when a defunctioning proximal protective loop ileostomy was considered advisable. Catheter ileostomy was constructed in the fashion of catheter jejunostomy, with postoperative saline irrigation. Results: Catheter ileostomy was performed in 20 patients in the 3-year period. The mean age of the subjects was 28.6 years and the male: female ratio was 1.86:1. Four patients died of septicemia and multiple organ failure unrelated to catheter ileostomy in the immediate postoperative period. Catheter ileostomy started functioning within 48 hours of the operation, and twice-daily irrigation was found sufficient in 81.25% of the surviving patients. Only one patient developed peritubal leak with mild skin excoriation that cleared within 5 days. Another patient with Koch's abdomen underwent conversion to loop colostomy on re-exploration for postoperative adhesive obstruction. There was no instance of intestinal leak. Ileostomy wounds closed spontaneously within 7–14 days of catheter removal, and none required formal closure. Hospital stay ranged from 12–35 days (mean: 23 days). Conclusions: Catheter ileostomy is effective in protecting intestinal anastomosis/repair; there is minimal morbidity and no catheter-related leak/mortality, and we recommend the procedure. PMID:21727735

Ansari, Maulana M.; Ahmad, Shakeel; Hasan, Syed H.; Haleem, Shahla

2011-01-01

419

External fixation for displaced 2-part proximal humeral fractures.  

PubMed

Studies have reported conflicting results regarding external fixation for displaced proximal humeral fractures. Compared with open reduction and internal fixation, external fixation for displaced proximal humeral fractures avoids dissection and soft tissue stripping and leads to higher union rates, a lower incidence of avascular necrosis, less scaring of the scapulohumeral interface, and faster rehabilitation. Some authors have reported good or excellent results and minimum complications compared with open reduction and internal fixation; however, others have reported that external fixation does not ensure acceptable reduction and fracture stability, especially in patients with osteoporosis.This article describes 18 patients with displaced 2-part fractures of the surgical neck of the humerus treated with closed reduction and external fixation using the Tension Guide Fixator (Gexfix SA, Carouge, Switzerland) external fixation system between 2010 and 2011. The patients included 14 women and 4 men with a mean age of 39 years. Mean follow-up was 18 months (range, 15-24 months). Fracture union; function using the Constant score, University of California Los Angeles score, Oxford score, and Quick Disabilities of the Arm, Shoulder and Hand shoulder score; and complications were evaluated. All patients experienced fracture union at a mean of 11 weeks (range, 9-13 weeks). The Tension Guide Fixator was removed without anesthesia at the outpatient clinic at a mean of 6 weeks (range, 4-8 weeks) with no loss of reduction or secondary displacement after removal. At 1-year follow-up, mean Constant and University of California Los Angeles scores were excellent, mean Oxford score showed satisfactory joint function, and mean Quick Disabilities of the Arm, Shoulder and Hand score showed minimal pain with no disability. PMID:23218629

Benetos, Ioannis S; Karampinas, Panayiotis K; Mavrogenis, Andreas F; Romoudis, Pavlos; Pneumaticos, Spiros G; Vlamis, John

2012-12-01

420

Childhood cancer and residential proximity to power lines  

PubMed Central

In the United Kingdom Childhood Cancer Study, a population-based case–control study covering the whole of England, Scotland and Wales, measured power-frequency magnetic fields were not found to be associated with risk for any malignancy. To examine further the risk associated with residential proximity to electricity supply equipment, distances to high-voltage lines, underground cables, substations and distribution circuits were collected for 3380 cases and 3390 controls. Magnetic field exposure from this equipment was calculated using distance, load and other circuit information. There was no evidence that either proximity to electrical installations or the magnetic field levels they produce in the UK is associated with increased risk of childhood leukaemia or any other cancer. Odds ratios of 0.73 (95% CI = 0.42–1.26) for acute lymphoblastic leukaemia, 0.75 (95% CI = 0.45–1.25) for all leukaemias, 1.08 (95% CI = 0.56–2.09) for central nervous system cancers and 0.92 (95% CI = 0.64–1.34) for all malignancies were obtained for residence within 50?m of an overhead line. When individuals with a calculated magnetic field exposure ? 0.2??T were compared to those in a reference category of exposure <0.1??T, odds ratios of 0.51 (95% CI = 0.11–2.33) for acute lymphoblastic leukaemia, 0.41 (95% CI = 0.09–1.87) for total leukaemia, 0.48 (95% CI =0.06–3.76) for central nervous system cancers and 0.62 (95% CI = 0.24–1.61) for all malignancies were obtained. © 2000 Cancer Research Campaign http://www.bjcancer.com PMID:11076671

2000-01-01

421

Surgical Treatment of Pathological Fractures Occurring at the Proximal Femur  

PubMed Central

Purpose To analyze the results of surgical treatment for pathological fractures at the proximal femur. Materials and Methods Nineteen patients with a pathological fracture were included. The mean age was 65.7 years old. The patients comprised 8 males and 11 females. Primary tumors, types of pathological fractures, surgical procedures, and postoperative complications were recorded. Musculoskeletal Tumor Society (MSTS) functional score was used for functional evaluation. A Kaplan-Meier survival analysis was used to determine survival rate. Results The primary malignancies were 6 cases of breast cancer, 3 cases of lung cancer, 3 cases of renal cell carcinoma, 2 cases of cholangiocarcinoma, 2 cases of hepatocellular carcinoma, 1 case of esophageal cancer, 1 case of colon cancer, and 1 case of ovarian cancer. Pathological fractures included 8 cases of pertrochanteric fractures and 11 cases of subtrochanteric fractures. Intramedullary nailing was performed in 10 cases, and joint replacement surgery was performed in 9 cases. Postoperative complications included local recurrence in 1 case, infection in 1 case, and nail breakage in 1 case. The mean postoperative MSTS score was 21. The mean survival period was 10.6 months. Patient survival rates were 42.1% after 6 months, 26.3% after 12 months, and 10.5% after 24 months. Conclusion Surgical treatment of pathological fractures at the proximal femur provided early ambulation, and excellent pain relief. The surgery was well tolerated emotionally. Surgery is necessary for improving the quality of life in such patients; however, more cases of pathological fractures in these regions should be subjected to detailed analysis. PMID:25683996

Choy, Won-Sik; Lee, Sang Ki; Yang, Dae Suk; Jeung, Sang Wook; Choi, Han Gyul; Park, Hyun Jong

2015-01-01

422

Unexplained proximal tibiofibular joint pain after high tibial osteotomy.  

PubMed

Problems of the proximal tibiofibular joint (pTFj) after high tibial osteotomy (HTO) are rare. With this case report, we strive to highlight the importance of investigating the pTFj in patients with unexplained knee pain after HTO. A 44 year old male patient presented with diffuse pain on his left knee 3 years after medial opening wedge HTO due to medial compartment overloading in a varus knee. Patient described persistent anterior tibial and lateral knee pain. 2 years after HTO, patient underwent implant removal but the knee pain persisted. As the reason for the persistent pain was not identified, further radiological evaluation was done. Single photon emission computerized tomography/computerized tomography (SPECT/CT) revealed that there was no increased uptake within the tibiofemoral joint, indicating a biologically well performed correction of the varus deformity. However, markedly increased tracer uptake was found at the pTFj. On the inherent axial CT scans, it was seen that the proximal screws were too long and placed within the pTFj. Along with this a severe osteoarthritis of the pTFj was identified. The cause of the patient's pain was then confirmed by a CT guided infiltration of local anesthetic. An arthrodesis of the pTFj was performed and at 12 months followup after the arthrodesis the patient was pain free. This case highlights how important it is to evaluate the pTFj in patients with unexplained pain after HTO. SPECT/CT was helpful in identifying the patient's problem in this challenging case. PMID:24932045

Testa, Enrique Adrian; Haeni, David L; Behrens, Gerrit; Hirschmann, Michael T

2014-05-01

423

New autophagy reporter mice reveal dynamics of proximal tubular autophagy.  

PubMed

The accumulation of autophagosomes in postischemic kidneys may be renoprotective, but whether this accumulation results from the induction of autophagy or from obstruction within the autophagic process is unknown. Utilizing the differential pH sensitivities of red fluorescent protein (RFP; pKa 4.5) and enhanced green fluorescent protein (EGFP; pKa 5.9), we generated CAG-RFP-EGFP-LC3 mice to distinguish early autophagic vacuoles from autolysosomes. In vitro and in vivo studies confirmed that in response to nutrient deprivation, renal epithelial cells in CAG-RFP-EGFP-LC3 mice produce autophagic vacuoles expressing RFP and EGFP puncta. EGFP fluorescence diminished substantially in the acidic environment of the autolysosomes, whereas bright RFP signals remained. Under normal conditions, nephrons expressed few EGFP and RFP puncta, but ischemia-reperfusion injury (IRI) led to dynamic changes in the proximal tubules, with increased numbers of RFP and EGFP puncta that peaked at 1 day after IRI. The number of EGFP puncta returned to control levels at 3 days after IRI, whereas the high levels of RFP puncta persisted, indicating autophagy initiation at day 1 and autophagosome clearance during renal recovery at day 3. Notably, proliferation decreased in cells containing RFP puncta, suggesting that autophagic cells are less likely to divide for tubular repair. Furthermore, 87% of proximal tubular cells with activated mechanistic target of rapamycin (mTOR), which prevents autophagy, contained no RFP puncta. Conversely, inhibition of mTOR complex 1 induced RFP and EGFP expression and decreased cell proliferation. In summary, our results highlight the dynamic regulation of autophagy in postischemic kidneys and suggest a role of mTOR in autophagy resolution during renal repair. PMID:24179166

Li, Ling; Wang, Zhao V; Hill, Joseph A; Lin, Fangming

2014-02-01

424

Simultaneous urethrocutaneous and urethrocavernous fistula after proximal corporospongiosal shunt for priapism.  

PubMed

Proximal corporospongiosal shunts are used for the most refractory cases of priapism. Here, we present the case of a 58-year-old man whose priapism was only partially responsive to phenylephrine injections and distal shunting. Proximal shunting was required, and he subsequently developed fistulization of the proximal penile urethra into the skin and the corpora cavernosa. The formation of simultaneous urethrocutaneous and urethrocavernous fistulae is a rare complication of proximal corporospongiosal shunts that can be initially managed with urinary diversion with a suprapubic tube. PMID:25733307

Manjunath, Adarsh S; Mazur, Daniel J; Han, Justin S; Gonzalez, Christopher M

2015-03-01

425

A refined flanged Bentall technique using Valsalva tube graft for proximal reinforcement.  

PubMed

Bleeding from the proximal suture line during aortic root replacement using a composite valve graft is a crucial and catastrophic problem. We present a simple flanged Bentall technique using a Valsalva tube graft to eliminate bleeding from the proximal suture line. The method is to wrap the proximal anastomosis completely by sewing the Valsalva flange to the residual aortic wall. The wrapping is facilitated by the use of part of a horizontally stretching Valsalva graft. This refined technique is effective and reproducible to prevent bleeding from the proximal suture line after the Bentall procedure. PMID:21497105

Koshiyama, Hiroshi; Nakajima, Masato; Amenomori, Syunsuke; Tsuchiya, Koji

2011-12-01

426

Proximal renal tubular acidosis: a not so rare disorder of multiple etiologies  

PubMed Central

Proximal renal tubular acidosis (RTA) (Type II RTA) is characterized by a defect in the ability to reabsorb HCO3 in the proximal tubule. This is usually manifested as bicarbonate wastage in the urine reflecting that the defect in proximal tubular transport is severe enough that the capacity for bicarbonate reabsorption in the thick ascending limb of Henle's loop and more distal nephron segments is overwhelmed. More subtle defects in proximal bicarbonate transport likely go clinically unrecognized owing to compensatory reabsorption of bicarbonate distally. Inherited proximal RTA is more commonly autosomal recessive and has been associated with mutations in the basolateral sodium-bicarbonate cotransporter (NBCe1). Mutations in this transporter lead to reduced activity and/or trafficking, thus disrupting the normal bicarbonate reabsorption process of the proximal tubules. As an isolated defect for bicarbonate transport, proximal RTA is rare and is more often associated with the Fanconi syndrome characterized by urinary wastage of solutes like phosphate, uric acid, glucose, amino acids, low-molecular-weight proteins as well as bicarbonate. A vast array of rare tubular disorders may cause proximal RTA but most commonly it is induced by drugs. With the exception of carbonic anhydrase inhibitors which cause isolated proximal RTA, drug-induced proximal RTA is associated with Fanconi syndrome. Drugs that have been recently recognized to cause severe proximal RTA with Fanconi syndrome include ifosfamide, valproic acid and various antiretrovirals such as Tenofovir particularly when given to human immunodeficiency virus patients receiving concomitantly protease inhibitors such as ritonavir or reverse transcriptase inhibitors such as didanosine. PMID:23235953

Haque, Syed K.; Ariceta, Gema; Batlle, Daniel

2012-01-01

427

Involvement of Reactive Oxygen Species in a Feed-forward Mechanism of Na/K-ATPase-mediated Signaling Transduction*  

PubMed Central

Cardiotonic steroids (such as ouabain) signaling through Na/K-ATPase regulate sodium reabsorption in the renal proximal tubule. We report here that reactive oxygen species are required to initiate ouabain-stimulated Na/K-ATPase·c-Src signaling. Pretreatment with the antioxidant N-acetyl-l-cysteine prevented ouabain-stimulated Na/K-ATPase·c-Src signaling, protein carbonylation, redistribution of Na/K-ATPase and sodium/proton exchanger isoform 3, and inhibition of active transepithelial 22Na+ transport. Disruption of the Na/K-ATPase·c-Src signaling complex attenuated ouabain-stimulated protein carbonylation. Ouabain-stimulated protein carbonylation is reversed after removal of ouabain, and this reversibility is largely independent of de novo protein synthesis and degradation by either the lysosome or the proteasome pathways. Furthermore, ouabain stimulated direct carbonylation of two amino acid residues in the actuator domain of the Na/K-ATPase ?1 subunit. Taken together, the data indicate that carbonylation modification of the Na/K-ATPase ?1 subunit is involved in a feed-forward mechanism of regulation of ouabain-mediated renal proximal tubule Na/K-ATPase signal transduction and subsequent sodium transport. PMID:24121502

Yan, Yanling; Shapiro, Anna P.; Haller, Steven; Katragadda, Vinai; Liu, Lijun; Tian, Jiang; Basrur, Venkatesha; Malhotra, Deepak; Xie, Zi-jian; Abraham, Nader G.; Shapiro, Joseph I.; Liu, Jiang

2013-01-01

428

Longitudinal and Circumferential Strain of the Proximal Aorta  

PubMed Central

Background Accurate assessment of mechanical properties of the proximal aorta is a requisite first step for elucidating the pathophysiology of isolated systolic hypertension. During systole, substantial proximal aortic axial displacement produces longitudinal strain, which we hypothesize causes variable underestimation of ascending aortic circumferential strain compared to values in the longitudinally constrained descending aorta. Methods and Results To assess effects of longitudinal strain, we performed magnetic resonance imaging in 375 participants (72 to 94 years old, 204 women) in the Age, Gene/Environment Susceptibility?Reykjavik Study and measured aortic circumferential and longitudinal strain. Circumferential ascending aortic area strain uncorrected for longitudinal strain was comparable in women and men (mean [95% CI], 8.3 [7.8, 8.9] versus 7.9 [7.4, 8.5]%, respectively, P=0.3). However, longitudinal strain was greater in women (8.5±2.5 versus 7.0±2.5%, P<0.001), resulting in greater longitudinally corrected circumferential ascending aortic strain (14.4 [13.6, 15.2] versus 13.0 [12.4, 13.7]%, P=0.010). Observed circumferential descending aortic strain, which did not require correction (women: 14.0 [13.2, 14.8], men: 12.4 [11.6, 13.2]%, P=0.005), was larger than uncorrected (P<0.001), but comparable to longitudinally corrected (P=0.12) circumferential ascending aortic strain. Carotid?femoral pulse wave velocity did not correlate with uncorrected ascending aortic strain (R=?0.04, P=0.5), but was inversely related to longitudinally corrected ascending and observed descending aortic strain (R=?0.15, P=0.004; R=?0.36, P<0.001, respectively). Longitudinal strain was also inversely related to carotid?femoral pulse wave velocity and other risk factors for higher aortic stiffness including treated hypertension. Conclusions Longitudinal strain creates substantial and variable errors in circumferential ascending aortic area strain measurements, particularly in women, and should be considered to avoid misclassification of ascending aortic stiffness. PMID:25523153

Bell, Vanessa; Mitchell, William A.; Sigurðsson, Sigurður; Westenberg, Jos J. M.; Gotal, John D.; Torjesen, Alyssa A.; Aspelund, Thor; Launer, Lenore J.; de Roos, Albert; Gudnason, Vilmundur; Harris, Tamara B.; Mitchell, Gary F.

2014-01-01

429

Interaction of ion tracks in spatial and temporal proximity.  

PubMed

In the present work, a systematic analysis of the impact of spatial and temporal proximity of ion tracks on the yield of higher-order radiolytic species as well as of DNA damage patterns is presented. This potential impact may be of concern when laser-driven particle accelerators are used for ion radiation therapy. The biophysical Monte Carlo track structure code PARTRAC was used and, to this end, extended in two aspects: first, the temporal information about track evolution has been included in the track structure module and, second, the simulation code has been modified to enable parallel multiple track processing during simulation of subsequent modelling stages. Depending on the spatial and temporal separation between ion-track pairs, the yield of chemical species has been calculated for incident protons with start energies of 20 MeV, for He(2+) ions with start energies of 1 and 20 MeV, and for 60 MeV C(6+) ions. Provided the overlap of the considered ion tracks is sufficient in all four dimensions (space and time), the yield of hydroxyl radicals was found to be reduced compared to that of single tracks, for all considered ion types. The biological endpoints investigated were base damages, single-strand breaks, double-strand breaks, and clustered lesions for incident pairs of protons and He(2+) ions, each with start energies of 20 MeV. The yield of clustered lesions produced by 20 MeV protons turned out to be influenced by the spatial separation of the proton pair; in contrast, no influence was found for different start times of the protons. The yield of single-strand breaks and base hits was found neither to depend on the spatial separation nor on the temporal separation between the incident protons. For incident 20 MeV He(2+) ions, however, a dependence on the spatial and temporal separation of the ion pair was found for all considered biological endpoints. Nevertheless, spatial proximity conditions where such intertrack effects were obtained are not met in the case of tumour radiation therapy; thus, no impact on radiation effects due to short pulse duration of laser-driven accelerators can be expected from alterations during the chemical stage. PMID:19597739

Kreipl, Maximilian Stephan; Friedland, Werner; Paretzke, Herwig G

2009-11-01

430

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. PMID:11786489

Leclere, Pascal G; Lefebvre, Romain A

2002-01-01

431

Report from NA49  

E-print Network

The signatures of the onset of deconfinement, found by the NA49 experiment at low SPS energies, are confronted with new results from the Beam Energy Scan (BES) program at BNL RHIC and CERN LHC results. Additionally, new NA49 results on chemical (particle ratio) fluctuations, azimuthal angle fluctuations, intermittency of di-pions, etc. are presented.

Katarzyna Grebieszkow; for the NA49 Collaboration

2011-12-04

432

Low renal uptake of 99m Tc-DMSA in patients with proximal tubular dysfunction  

Microsoft Academic Search

In nine patients with different types of proximal tubulopathy and a nearly normal glomerular filtration rate a low uptake of 99mTc-DMSA in the kidneys was found. The underlying mechanism seems to be an increased urinary excretion of 99mTc-DMSA. This radiopharmaceutical might be used as a marker of proximal tubular dysfunction.

W. H. J. van Lu; G. J. Ensing; D. A. Piers

1983-01-01

433

Does Geographical Proximity Still Matter? An Empirical Analysis of Two Long-Term Relational Databases  

E-print Network

to science-industry collaborations in France, and on two complementary indicators of geographical proximity1 Does Geographical Proximity Still Matter? An Empirical Analysis of Two Long- Term Relational of this article is to provide possible answers, at an empirical level, to the question "Does geographical

Paris-Sud XI, Université de

434

Proximate illiteracy and modern contraceptive use in India: Analysis of DHS data  

Microsoft Academic Search

This paper examines the hypothesis that contraceptive use of illiterate women having literate partners (proximate literates), may be higher than that of illiterate women whose partners too are illiterates (isolate illiterates) using Demographic Health Survey data for India (2005-2006). Results reveal that the proximate illiteracy effect is significant, though restricted to specific groups; it varies according to contraceptive method; increasing

Zakir Husain; Mousumi Dutta

2012-01-01

435

Base-contact proximity effects in bipolar transistors with nitride-spacer technology  

E-print Network

Base-contact proximity effects in bipolar transistors with nitride-spacer technology Henk van Zeijl-BJT's with spacer separated Al/Si emitter and base contacts are fabricated and characterized. Due to the proximity of the base contact to the emitter-base junction, the base current is increased by two peripheral effects

Technische Universiteit Delft

436

Proximity Effects of Metallic Environments on High Frequency RFID Reader Antenna: Study and Applications  

Microsoft Academic Search

We study the proximity effects of metallic environments on the performance of high frequency (HF) radio frequency identification (RFID) reader antenna operating at 13.56 MHz. The performance of a typical HF RFID reader loop antenna in the proximity of various metal plate configurations is experimentally investigated in terms of resonant frequency, field intensity, and field distribution. The study shows that

Xianming Qing; Zhi Ning Chen

2007-01-01

437

Helping or Hovering? Effects of Instructional Assistant Proximity on Students with Disabilities  

Microsoft Academic Search

This study presents data on the effects of the proximity of instructional assistants on stu- dents with multiple disabilities who are placed in general education classrooms. Based on extensive observations and interviews, analyses of the data highlighted eight major findings of educational significance, all related to proximity of instructional assistants. Categories of findings and discussion include (a) interference with ownership

Michael F. Giangreco; Susan W. Edelman; Stephanie Z. C. MacFarland

1997-01-01

438

CPMC: An Efficient Proximity Malware Coping Scheme in Smartphone-based Mobile Networks  

E-print Network

CPMC: An Efficient Proximity Malware Coping Scheme in Smartphone-based Mobile Networks Feng Li and services. At the same time, smartphones are also increasingly becoming the target of malware. Many emerging a portion of the smartphones will have malware detection capabilities. The threats of proximity malware

Wu, Jie

439

Privacy-Preserving Profile Matching for Proximity-based Mobile Social Networking  

E-print Network

, and almost all smartphones have WiFi and Bluetooth interfaces. PMSN refers to the social interaction among1 Privacy-Preserving Profile Matching for Proximity-based Mobile Social Networking Rui Zhang, and Guanhua Yan Abstract--Proximity-based mobile social networking (PMSN) refers to the social interaction

Zhang, Yanchao

440

Risk factor analysis for proximal and distal reoperations after surgery for acute type A aortic dissection  

Microsoft Academic Search

Objective: This study was undertaken to determine significant risk factors for proximal or distal reoperations after surgical correction of acute type A aortic dissection. Methods: Between 1980 and 2000, a total of 160 consecutive patients (mean age 57.5 ± 13.3 years, 126 men) underwent surgery for acute type A aortic dissection. Proximal repair was performed by means of ascending aorta

Matthias Kirsch; Céline Soustelle; Rémi Houël; Marie Line Hillion; Daniel Loisance

2002-01-01

441

Hip abductor moment arm - a mathematical analysis for proximal femoral replacement  

Microsoft Academic Search

BACKGROUND: Patients undergoing proximal femoral replacement for tumor resection often have compromised hip abductor muscles resulting in a Trendelenberg limp and hip instability. Commercially available proximal femoral prostheses offer several designs with varying sites of attachment for the abductor muscles, however, no analyses of these configurations have been performed to determine which design provides the longest moment arm for the

Eric R Henderson; German A Marulanda; David Cheong; H Thomas Temple; G Douglas Letson

2011-01-01

442

Effects of neuromuscular electrical stimulation on the range of motion recovery in hand proximal interphalangeal sprain  

E-print Network

Effects of neuromuscular electrical stimulation on the range of motion recovery in hand proximal ­ Neuromuscular electrical stimulation / Sprain / Hand / Proximal interphalangeal joint. hal-00412991,version1 of the neuromuscular electrical stimulation (NMES), none has yet assessed, to the best of our knowledge, the possible

Paris-Sud XI, Université de

443

Maintaining Interaction at the Zone of Proximal Development through Reflexive Practice and Action Research  

ERIC Educational Resources Information Center

In this study, dialectical reflexive practice is used to maintain student-teacher interactions in the zone of proximal development. The zone of proximal development is the development-and-learning unit of the child or learner and the author suggests that it is also the fusion point of Marx's dialectical historical materialism: the creation of…

Lisle, Angela

2006-01-01

444

Proximal tubule reabsorption after hyperoncotic albumin infusion. Role of parathyroid hormone and dissociation from plasma volume.  

PubMed

Preferential expansion of the plasma volume by infusion of salt-poor hyperoncotic albumin solution decreases sodium reabsorption by the proximal tubule. The present micropuncture studies test the thesis that albumin infusion depresses proximal reabsorption by an effect unrelated to expansion of the plasma volume, perhaps due to an effect of parathyroid hormone (PTH) on proximal sodium reabsorption. Infusion of salt-poor hyperoncotic albumin significantly decreased plasma ionized calcium, increased immunoreactive PTH (iPTH) in plasma, decreased sodium reabsorption by the proximal tubule, and increased phosphate clearance. In contrast, infusions of albumin, in which the ionized calcium was restored to normal plasma levels, had no significant effect on ionized calcium, iPTH, proximal reabsorption, or phosphate clearance in intact dogs. Similarly, in parathyroidectomized animals given a constant replacement infusion of PTH, albumin infusion had no significant effect on proximal reabsorption or phosphate clearance. Plasma volume was markedly expanded following albumin infusion in all groups of dogs. These findings (a) indicate that PTH plays a significant role in the decrease in sodium reabsorption by the renal proximal tubule after salt-poor hyperoncotic albumin infusion, and (b) dissociate preferential expansion of the plasma volume from decreases in sodium reabsorption by the proximal tubule. PMID:11344563

Knox, F G; Schneider, E G; Willis, L R; Strandhoy, J W; Ott, C E; Cuche, J L; Goldsmith, R S; Arnaud, C D

1974-02-01

445

The Effect of Ethnolinguistic Differences on Proximity between Cantonese and Mandarin Speaking Children.  

ERIC Educational Resources Information Center

Examined effects of ethnolinguistic differences on social proximity between Cantonese- and Mandarin-speaking Chinese children in a day care center. Found that each group of children was more likely to be in closer proximity to children speaking their own language than to children speaking the other language during free choice floor- and group-time…

Leung, Lanna Oi-Ling; Lewis, George F.

1999-01-01

446

Proximity Judgments in Color Space: Tests of a Euclidean Color Geometry  

Microsoft Academic Search

We describe two tests of the hypothesis that human judgments of the proximity of colors are consistent with a Euclidean :geometry on color matching space. The first test uses proximity judgments to measure the angle between any two intersecting lines in color space. Pairwise estimates of the angles between three lines in a plane were made in order to test

SOPHIE M. WUERGER; LAURENCE T. MALONEY; JOHN KRAUSKOPF

1995-01-01

447

Proximity and Visibility of Fruits and Vegetables Influence Intake in a Kitchen Setting among College Students  

ERIC Educational Resources Information Center

The hypothesis that participants will eat more fruits (apple slices) and vegetables (carrot cuts) if they are made more proximate and visible was tested using a 2 × 2 between-participants design. Proximity was manipulated by placing fruits and vegetables in a bowl at a table where participants sat (near) or 2 m from the table (far). Visibility was…

Privitera, Gregory J.; Creary, Heather E.

2013-01-01

448

Knowledge Collaboration and ProximityThe Spatial Organization of Biotech Innovation Projects  

Microsoft Academic Search

This article addresses the role of proximity for knowledge collaboration between dedicated biotechnology firms (DBFs) and related actors. Innovation projects managed by a selection of eight Swedish DBFs are analysed in detail and classified with regard to their specific knowledge characteristics. Based on this classification, explanations to the relative importance of functional and relational proximity to collaborators are sought.The findings

Jerker Moodysson; Ola Jonsson

2007-01-01

449

Using Proximity and Quantized RSS for Sensor Localization in Wireless Networks  

E-print Network

Using Proximity and Quantized RSS for Sensor Localization in Wireless Networks Neal Patwari, received signal strength (RSS) and proximity (also known as connectivity) measurements have been proposed as simple and inexpensive means to es- timate range between devices and sensor location. While RSS

Hero, Alfred O.

450

Using proximity and quantized RSS for sensor localization in wireless networks  

Microsoft Academic Search

For wireless sensor networks, received signal strength (RSS) and proximity (also known as connectivity) measurements have been proposed as simple and inexpensive means to estimate range between devices and sensor location. While RSS measurements are recognized to suffer from errors due to the random nature of the fading channel, proximity measurements, ie., knowing only whether or not two devices are