WorldWideScience
 
 
1

Connector for the pneumatical and electrical coupling between a gases supply means and a gas conduit  

UK PubMed Central (United Kingdom)

The present invention relates to the connections between respiratory humidifiers and/or other such devices and heated breathing conduits used to couple a patient to the humidifier. In particular, the invention is a connector to couple a gases supply means and a conduit, such that the connector causes there to be an electrical and pneumatic, that is, scaled connection between a conduit including an electrical wire extending within, throughout or about it and a gases supply device, such as a humidifier, blower or the like. The connector may be of a single port type or a dual port type. The dual port type connector is suitable for ventilator apparatus that have a dry line (dry breathing conduit) extending from a ventilator or blower that carries dry gas to a humidifier and an inspiratory limb that extends from the humidifier to the patient and carries humidified gases to the patient.

Deshita Airawana Edirisuriya; Poh Ming Laurent Kristopher

2

Fuel cell with integral conduit means for statically removing liquid product water  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a fuel cell. It comprises an anode, an electrolyte, a cathode, a cathode chamber and a means for removing static product water from the cathode chamber characterized in that the means for static product water removal comprises a wick positioned at the base of and extending at least substantially the entire length of the cathode chamber. The wick being in contact with at least one exhaust manifold structure exiting the cathode chamber wherein the manifold structure contains a conduit structure which is permeable to liquid but impermeable to gas at gas pressures below the bubble pressure, P of the conduit structure where the bubble pressure, P is related to the pore size of the structure.

McElroy, J.F.

1989-10-24

3

Means and method for vapor generation  

Energy Technology Data Exchange (ETDEWEB)

A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid--starting as "feedwater" heating where no vapors are present, progressing to "nucleate" heating where vaporization begins and some vapors are present, and concluding with "film" heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10-30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.

Carlson, Larry W. (Oswego, IL)

1984-01-01

4

Electrically controllable anesthesia vaporizer  

UK PubMed Central (United Kingdom)

A vaporizer has a main conduit supplied at an inlet end by a carrier gas of oxygen and nitrous oxide having a constant flow rate. The outlet end of the conduit is connected to the breathing system of a patient. A series circuit with an input end connected to a proximal port in the conduit includes a check valve, a chamber in which anesthetic vapor is maintained in saturation and a positive displacement pump driven by an electrical motor for pumping the vapor-saturated gas at a rate that is only a function of an electrical signal applied to the motor. The output of the pump is connected to a distal port of the conduit. More than one such chamber may be provided, each containing a different liquid anesthetic, and any one being connected into the circuit by means of a selector valve.

RUSZ TIBOR; HALLOWELL W STETSON

5

Mercury vapor control by means of corona discharge  

Energy Technology Data Exchange (ETDEWEB)

The work reported here describes the construction and performance of a novel corona discharge flue gas reactor designed to oxidize mercury vapor, allowing the mercuric oxide to be subsequently captured in a downstream particulate control device. A corona discharge in flue gas produces oxidizing radicals, such as OH and atomic oxygen, which can then react with elemental mercury. Optimum performance demands that the corona discharge, and hence the oxidizing radicals, be uniformly distributed within the flow volume of the reactor. When a uniform volume distribution of electrons is achieved, then uniform exposure and treatment of the gas is assured, and maximum energy efficiency can be obtained. By means of a laboratory based, pilot scale system, it is shown that the spatially distributed corona discharge produced by the corona reactor operating at low power level and short residence time yields a high level of mercury vapor oxidation. The mercuric oxide, in the form of solid particles, can then be removed by a conventional electrostatic precipitator or fabric filter. It is also shown that low temperature, high humidity conditions enhance mercury oxidation. For an application to solid waste incineration, this suggests the placement of the reactor downstream of the spray dryer and upstream of the fabric filter. Economic analysis indicates that this method of mercury vapor control is very competitive with adsorption by activated carbon. For example, if mercury control regulations are promulgated for coal burning power plants, the corona discharge technology could potentially save the US utility industry and electricity consumers up to 250 million dollars per year. 10 refs., 6 figs., 2 tabs.

Helfritch, D.; Harmon, G.; Feldman, P. [Environmental Elements Corp., Baltimore, MD (United States)

1996-12-31

6

Connector for breathing conduits  

UK PubMed Central (United Kingdom)

The present invention relates to the connections between respiratory humidifiers and/or other such devices and heated breathing conduits used to couple a patient to the humidifier. In particular, the invention is a connector to couple a gases supply means and a conduit, such that the connector causes there to be an electrical and pneumatic, that is, sealed connection between a conduit including an electrical wire extending within, throughout or about it and a gases supply device, such as a humidifier, blower or the like. The connector may be of a single port type or a dual port type. The dual port type connector is suitable for ventilator apparatus that have a dry line (dry breathing conduit) extending from a ventilator or blower that carries dry gas to a humidifier and an inspiratory limb that extends from the humidifier to the patient and carries humidified gases to the patient.

EDIRISURIYA DESHITHA AIRAWANA; LAURENT KRISTOPHER POH MING

7

Oil collection/recirculation for vapor-compression refrigeration system  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a vapor-compression refrigeration system: an oil lubricated compressor, a condenser and an evaporator interconnected by conduit means to form a closed circuit for circulation of a refrigerant fluid; at least part of the conduit means comprising a refrigerant vapor return conduit for conducting refrigerant vapor from the evaporator to the compressor, the compressor being disposed at a vertical elevation above the evaporator; reservoir means in fluid flow communication with the refrigerant vapor return conduit for collecting oil separated from the refrigerant fluid; means for pumping oil from the reservoir means to the compressor through a separate oil return conduit; a fluid operated motor adapted to be driven by refrigerant fluid from the refrigeration system, the motor driving the pumping means; and control means, including first liquid level sensing means, for sensing a predetermined accumulation of oil in the reservoir means and causing the pumping means to be energized to pump oil from the reservoir means to the compressor; the first liquid level sensing means including switch means interposed in a control circuit and operable to cause the control circuit to energize the pumping means; the control circuit adapted to open and close a refrigerant flow control valve for controlling the flow of refrigerant fluid through the fluid operated motor. The control circuit further is operable to energize and deenergize the motor to prevent more than a predetermined quantity of oil from accumulating in the reservoir means.

Toub, S.G.; Gilliland, J.L. Jr.; Holder, H.W.

1986-12-02

8

Esophageal conduit necrosis.  

UK PubMed Central (United Kingdom)

A cumulative review of the prevalence of esophageal conduit necrosis is summarized in Table 4. The spectrum of conduit ischemia is broad and includes cases in which there is anastomotic leak or stricture as well as cases in which there is frank graft necrosis. Many of the studies that the authors reviewed do not specify the exact nature of postoperative ischemic complications or how they are defined. Therefore, postoperative conduit ischemia is reported globally. Based on the authors' review, average rates of ischemic complications for stomach, colon, and jejunum are 3.2%, 5.1%, and 4.2%, respectively. Results for colon and jejunum include results for both long- and short-segment grafting. Most reports that compare outcomes using different esophageal conduits demonstrate findings similar to the authors'. Davis and colleagues compared results with colon versus gastric conduit esophageal reconstruction. They found that operative mortality, anastomotic leaks, and conduit ischemia rates were all lower for the stomach than for the colon. Specifically, ischemia of the stomach conduit was 0.5%, compared with 2.4% for the colon conduit. Moorehead and Wong, in a large series of 760 esophagectomy patients in whom the stomach, colon, or jejunum was used for reconstruction, demonstrated that the stomach had the lowest incidence of conduit ischemia (1%), followed by jejunum (11.3%), then colon (13.3%). Some of the factors they identified as correlating with the risk of ischemia include length of conduit, technique of stomach graft preparation, whether anastomosis is in the neck or chest, and route of passage of the conduit. Mansour and colleagues compared their results using bowel interposition (either colon or jejunum) to reconstruct the resected esophagus. The authors report an overall mortality of 5.9%, and 3% conduit ischemia. All ischemia was noted in the colon conduits harvested from the left side. No ischemic complications were noted from jejunal segments. Briel and colleagues compared stomach versus colon conduit use after esophagectomy. They note an overall incidence of ischemia of 9.2%. In their series, the incidence of ischemia for stomach and colon was 10.4% and 7.4%, respectively. Anastomotic leak and stricture rates, both thought to be sequelae of ischemia, also were lower for colon conduit use than for stomach conduit. Multivariate analysis identified patient comorbidities as the only independent risk factor for conduit ischemia. The authors use their findings to support the preferential use of colon conduits rather than stomach conduits. The incidence of colon conduit ischemia (7.4%) is directly in line with all other published results, including the cumulative review by the authors of this article, whereas the rate of stomach conduit ischemia (10.4%) is considerable higher than in most other studies. Esophageal conduit necrosis is an uncommon but disastrous complication of esophageal surgery. Careful selection of patients for surgery, preoperative evaluation of the proposed conduit, and meticulous operative technique are the best defenses against conduit ischemia. Postoperatively, surgeons should have a high index of suspicion for this complication. Unexplained tachycardia, respiratory failure, leukocytosis, or any evidence for graft or anastomotic leak should prompt a search for conduit ischemia. The diagnosis is made by contrast esophagography, endoscopy, or direct operative inspection. There is no documented salvage technique once ischemia is identified. Treatment for mild cases may be supportive, with or without management of anastomotic leak. More severe cases of necrosis require débridement and conduit take-down with proximal esophageal diversion and placement of enteral feeding tubes. Reconstruction can be planned for later if possible. The majority of the data demonstrates that risk of ischemia is related to conduit type, length of conduit, comorbidities, and operative technique. The stomach has the lowest reported incidence of conduit ischemia, followed by the jejunum, and colon. In the future, methods to p

Wormuth JK; Heitmiller RF

2006-02-01

9

Studies on formation of unconfined detonable vapor cloud using explosive means.  

UK PubMed Central (United Kingdom)

Certain organic liquid fuels like hydrocarbons, hydrocarbon oxides, when dispersed in air in the form of small droplets, mix with surrounding atmosphere forming vapor cloud (aerosol) and acquire explosive properties. This paper describes the studies on establishment of conditions for dispersion of fuels in air using explosive means resulting in formation of detonable aerosols of propylene oxide and ethylene oxide. Burster charges based on different explosives were evaluated for the capability to disperse the fuels without causing ignition. Parameters like design of canister, burster tube, burster charge type, etc. have been studied based on dispersion experiments. The detonability of the aerosol formed by the optimized burster charge system was also tested.

Apparao A; Rao CR; Tewari SP

2013-06-01

10

Studies on formation of unconfined detonable vapor cloud using explosive means.  

Science.gov (United States)

Certain organic liquid fuels like hydrocarbons, hydrocarbon oxides, when dispersed in air in the form of small droplets, mix with surrounding atmosphere forming vapor cloud (aerosol) and acquire explosive properties. This paper describes the studies on establishment of conditions for dispersion of fuels in air using explosive means resulting in formation of detonable aerosols of propylene oxide and ethylene oxide. Burster charges based on different explosives were evaluated for the capability to disperse the fuels without causing ignition. Parameters like design of canister, burster tube, burster charge type, etc. have been studied based on dispersion experiments. The detonability of the aerosol formed by the optimized burster charge system was also tested. PMID:23618658

Apparao, A; Rao, C R; Tewari, S P

2013-03-21

11

Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full -- Part 4: Venturi tubes  

CERN Multimedia

ISO 5167-4:2003 specifies the geometry and method of use (installation and operating conditions) of Venturi tubes when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. ISO 5167-4:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-4:2003 is applicable only to Venturi tubes in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of these devices can only be used within specified limits of pipe size, roughness, diameter ratio and Reynolds number. ISO 5167-4:2003 is not applicable to the measurement of pulsating flow. It does not cover the use of Venturi tubes in pipes sized less than 50 mm or more than 1 200 mm, or for where the pipe Reynolds numbers are below 20 000. ISO 5167-4:2003 deals with the three types of classical Venturi tubes: cast, machined and rough welde...

International Organization for Standardization. Geneva

2003-01-01

12

Seal arrangement for intersecting conduits  

International Nuclear Information System (INIS)

A seal arrangement in which two intersecting conduits are sealed from each other is described. A sleeve insert is locked in a sealed relationship within one conduit enclosing the openings of the intersecting conduit

1980-01-01

13

Seal arrangement for intersecting conduits  

Energy Technology Data Exchange (ETDEWEB)

A seal arrangement in which two intersecting conduits are sealed from each other. A sleeve insert is locked in a sealed relationship within one conduit enclosing the openings of the intersecting conduit.

Goedicke, Friedrich E. (Trafford, PA)

1980-01-01

14

Nano structured physical vapor deposited coatings by means of picosecond laser radiation.  

UK PubMed Central (United Kingdom)

Molding of nano structures by injection molding leads to special requirements for the tools e.g., wear resistance and as low as possible release forces of the molded components. On the other hand it is not allowed to affect the replication precision. Physical vapor deposition is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the plastics melt. Although physical vapor deposition technology allows the deposition of films on micro structures without changing the structure significantly, film deposition on nano structures and small micro structures leads to a relevant change in surface topography. For this reason direct structuring of physical vapor deposition coatings might be beneficial. In this paper structuring was done using a picoseconds ultraviolet laser, Lumera Laser "Rapid," with a master oscillator power amplifier system at 355 nm. Two different coatings were deposited by magnetron sputter ion plating physical vapor deposition technology for laser structuring tests ((Cr, Al)N, (Cr, Al,Si)N). After deposition, the coatings were analyzed by common techniques regarding hardness, Young's modulus and morphology. The structures were analyzed by scanning electron microscopy. The results show a high potential for laser structuring of coatings deposited via physical vapor deposition. Linear structures with sizes between 400 nm and 10microm were realized.

Bobzin K; Bagcivan N; Ewering M; Gillner A; Beckemper S; Hartmann C; Theiss S

2011-10-01

15

Flexible cryogenic conduit  

Energy Technology Data Exchange (ETDEWEB)

A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament.

Brindza, P.D.; Wines, R.R.; Takacs, J.J.

1999-12-21

16

Flexible cryogenic conduit  

Energy Technology Data Exchange (ETDEWEB)

A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament.

Brindza, Paul Daniel (Yorktown, VA); Wines, Robin Renee (Norfolk, VA); Takacs, James Joseph (Hayes, VA)

1999-01-01

17

Portable conduit retention apparatus for releasably retaining a conduit therein  

Energy Technology Data Exchange (ETDEWEB)

Portable conduit retention apparatus is described for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor. 6 figs.

Metzger, R.H.

1998-07-07

18

Portable conduit retention apparatus for releasably retaining a conduit therein  

Energy Technology Data Exchange (ETDEWEB)

Portable conduit retention apparatus for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor.

Metzger, Richard H. (West Seneca, NY)

1998-01-01

19

Method and device for separating gaseous or vaporous materials, especially isotopes, by means of separation nozzles  

International Nuclear Information System (INIS)

The present invention relates to methods and devices for separating gaseous or vaporous substances, especially isotopes, with different molecular weights and/or different gas kinetic cross sections in which the mixture of substances to be separated and a lighter additional gas are passed through nozzles whereupon one or several skimmer diaphragms projecting into the flow path of the substances are used to separate and remove fractions of different compositions and in which several separation nozzle systems consisting of nozzles and skimmer diaphragms are connected so as to constitute a cascade.

1974-07-30

20

Combination downflow-upflow vapor-liquid separator  

Energy Technology Data Exchange (ETDEWEB)

An improved vapor-liquid separator having a vertically disposed conduit for flow of a mixture. A first, second and third plurality of curved arms penetrate and extend within the conduit. A cylindrical member is radially spaced from the conduit forming an annulus therewith and having perforations and a retaining lip at its upper end.

Kidwell, John H. (Uniontown, OH); Prueter, William P. (Alliance, OH); Eaton, Andrew M. (Alliance, OH)

1987-03-10

 
 
 
 
21

Method and device for separating gaseous or vaporous materials, especially isotopes, by means of separation nozzles  

International Nuclear Information System (INIS)

A method is provided for separating gaseous or vaporous substances, especially isotopes, with different molecular weights and/or different gas kinetic cross sections, in which the mixture of substances to be separated is passed through separation nozzles. One or more skimmer diaphragms project into the flow path of the substances and are used to separate and remove fractions of different compositions, and several separation systems consisting of nozzles and skimmer diaphragms are arranged in a cascade. The cascade generates partial streams which contain the mixture of substances to be separated. The partial streams can contain an additional gas with each partial stream containing different fractions of additional gas. When the partial streams generated within the cascade contain different fractions of additional gas, the partial streams are jointly fed to one of the separation nozzle systems in such a way as to generate a molar fraction gradient with respect to the additional gas which is opposed in direction to the molar fraction gradient being generated by the separation process within the nozzle. The partial streams can contain different compositions of the mixture of substances to be separated. When the partial streams generated within the cascade contain different compositions of the mixture of substances to be separated, the partial streams are jointly fed to one of the separation nozzle systems in such a way as to generate a molar fraction ratio with respect to the substances to be separated which is identical in direction with the molar fraction gradient being generated by the separation process within the nozzle. 27 claims, 13 figures.

1976-01-01

22

CABLE CONDUIT FOR HOSPITAL BED  

UK PubMed Central (United Kingdom)

A patient-support apparatus has a frame including a pair of laterally spaced apart first and second rails and a set of cross members interconnecting the first and second rails. The first and second rails each terminate near a head end and a foot end of the patient-support apparatus. A patient support platform includes at least one pivotable deck section and is carried by the frame. A cable conduit is coupled to the set of cross members and extends parallel with the first and second rails. The cable conduit supports a plurality of electrical cables that extend between the head end and foot end of the patient-support apparatus.

HORNBACH DAVID W; METZ DARRELL L; STRATMAN TERRY J

23

Urodynamic evaluation of ileal conduit function.  

Science.gov (United States)

Bilateral hydroureteronephrosis following ileal conduit urinary diversion is not uncommon. It may be owing to ureteroileal stenosis, stomal stenosis or a poorly compliant ileal conduit. The standard evaluation of stoma size, conduit residual urine and a loopogram often fail to allow determination of the cause of ureteral dilatation. In addition to these standard tests, we have used conduit urodynamics to study conduit function with a triple lumen urodynamic catheter to measure simultaneously conduit pressure proximal and distal to the fascia during filling under fluoroscopy. In 4 control patients with normal upper tracts who were studied with this technique conduit leak point pressures ranged from 5 to 20 cm. water pressure. Six patients with bilateral hydroureteronephrosis were studied to evaluate conduit function. We found abnormalities in 5 patients, including functional stomal stenosis in 2, an atonic loop in 1, segmental obstruction in 1 and a high pressure noncompliant distal segment in 1. PMID:3573186

Knapp, P M; Konnak, J W; McGuire, E J; Savastano, J A

1987-05-01

24

Urodynamic evaluation of ileal conduit function.  

UK PubMed Central (United Kingdom)

Bilateral hydroureteronephrosis following ileal conduit urinary diversion is not uncommon. It may be owing to ureteroileal stenosis, stomal stenosis or a poorly compliant ileal conduit. The standard evaluation of stoma size, conduit residual urine and a loopogram often fail to allow determination of the cause of ureteral dilatation. In addition to these standard tests, we have used conduit urodynamics to study conduit function with a triple lumen urodynamic catheter to measure simultaneously conduit pressure proximal and distal to the fascia during filling under fluoroscopy. In 4 control patients with normal upper tracts who were studied with this technique conduit leak point pressures ranged from 5 to 20 cm. water pressure. Six patients with bilateral hydroureteronephrosis were studied to evaluate conduit function. We found abnormalities in 5 patients, including functional stomal stenosis in 2, an atonic loop in 1, segmental obstruction in 1 and a high pressure noncompliant distal segment in 1.

Knapp PM Jr; Konnak JW; McGuire EJ; Savastano JA

1987-05-01

25

Empirical model for mean temperature for Indian zone and estimation of precipitable water vapor from ground based GPS measurements  

Directory of Open Access Journals (Sweden)

Full Text Available Estimation of precipitable water (PW) in the atmosphere from ground-based Global Positioning System (GPS) essentially involves modeling the zenith hydrostatic delay (ZHD) in terms of surface Pressure (Ps) and subtracting it from the corresponding values of zenith tropospheric delay (ZTD) to estimate the zenith wet (non-hydrostatic) delay (ZWD). This further involves establishing an appropriate model connecting PW and ZWD, which in its simplest case assumed to be similar to that of ZHD. But when the temperature variations are large, for the accurate estimate of PW the variation of the proportionality constant connecting PW and ZWD is to be accounted. For this a water vapor weighted mean temperature (Tm) has been defined by many investigations, which has to be modeled on a regional basis. For estimating PW over the Indian region from GPS data, a region specific model for Tm in terms of surface temperature (Ts) is developed using the radiosonde measurements from eight India Meteorological Department (IMD) stations spread over the sub-continent within a latitude range of 8.5°–32.6° N. Following a similar procedure Tm-based models are also evolved for each of these stations and the features of these site-specific models are compared with those of the region-specific model. Applicability of the region-specific and site-specific Tm-based models in retrieving PW from GPS data recorded at the IGS sites Bangalore and Hyderabad, is tested by comparing the retrieved values of PW with those estimated from the altitude profile of water vapor measured using radiosonde. The values of ZWD estimated at 00:00 UTC and 12:00 UTC are used to test the validity of the models by estimating the PW using the models and comparing it with those obtained from radiosonde data. The region specific Tm-based model is found to be in par with if not better than a similar site-specific Tm-based model for the near equatorial station, Bangalore. A simple site-specific linear relation without accounting for the temperature effect through Tm is also found to be quite adequate for Bangalore. But for Hyderabad, a station located at slightly higher latitude, the deviation for the linear model is found to be larger than that of the Tm-based model. This indicates that even though a simple linear regression model is quite adequate for the near equatorial stations, where the temperature variations are relatively small, for estimating PW from GPS data at higher latitudes this model is inferior to the Tm-based model.

C. Suresh Raju; K. Saha; B. V. Thampi; K. Parameswaran

2007-01-01

26

Effects of hydrogen water vapor atmospheres upon vaporization of UO2-based complex oxides with Sr, Ba, and Cs by means of high temperature mass spectrometry  

International Nuclear Information System (INIS)

For analysis of fission products release and transportation in severe accidents of nuclear reactors, vaporization behaviors of BaUO3, SrUO3, Cs2UO4, and Cs2U4O12 were investigated by using a Knudsen effusion high temperature mass spectrometer. To simulate water vapor and hydrogen environments in severe accident conditions of nuclear reactors, the environmental conditions inside the Knudsen cell were controlled by introducing proper amounts of gases, such as D2(g), D2O(g), O2(g), or their mixtures from outside reservoirs. To maintain dynamic equilibrium being established inside the Knudsen cell, however, the amount of input gas can not be too large. So the experimental result from the mass spectrometry can only apply for a small range of environmental conditions compared to those in a real severe accident of nuclear reactors. A calculation was made by using computer code Chemsage for other possible environmental conditions, such as wet condition with high H2O(g)/H2(g) ratio, reducing condition with low H2O(g)/H2(g) ratio, high temperatures up to 2500 K and high pressures up to 1 MPa. Both the experimental results and the calculation showed that environmental conditions have a great influence on vaporization properties of these compounds. (author)

1999-01-01

27

Empirical model for mean temperature for Indian zone and estimation of precipitable water vapor from ground based GPS measurements  

Energy Technology Data Exchange (ETDEWEB)

Estimation of precipitable water (PW) in the atmosphere from ground-based Global Positioning System (GPS) essentially involves modeling the zenith hydrostatic delay (ZHD) in terms of surface Pressure (P{sub s}) and subtracting it from the corresponding values of zenith tropospheric delay (ZTD) to estimate the zenith wet (non-hydrostatic) delay (ZWD). This further involves establishing an appropriate model connecting PW and ZWD, which in its simplest case assumed to be similar to that of ZHD. But when the temperature variations are large, for the accurate estimate of PW the variation of the proportionality constant connecting PW and ZWD is to be accounted. For this a water vapor weighted mean temperature (T{sub m}) has been defined by many investigations, which has to be modeled on a regional basis. For estimating PW over the Indian region from GPS data, a region specific model for T{sub m} in terms of surface temperature (T{sub s}) is developed using the radiosonde measurements from eight India Meteorological Department (IMD) stations spread over the sub-continent within a latitude range of 8.5 -32.6 N. Following a similar procedure T{sub m}-based models are also evolved for each of these stations and the features of these site-specific models are compared with those of the region-specific model. Applicability of the region-specific and site-specific T{sub m}-based models in retrieving PW from GPS data recorded at the IGS sites Bangalore and Hyderabad, is tested by comparing the retrieved values of PW with those estimated from the altitude profile of water vapor measured using radiosonde. The values of ZWD estimated at 00:00 UTC and 12:00 UTC are used to test the validity of the models by estimating the PW using the models and comparing it with those obtained from radiosonde data. The region specific T{sub m}-based model is found to be in par with if not better than a similar site-specific T{sub m}-based model for the near equatorial station, Bangalore. A simple site-specific linear relation without accounting for the temperature effect through T{sub m} is also found to be quite adequate for Bangalore. But for Hyderabad, a station located at slightly higher latitude, the deviation for the linear model is found to be larger than that of the T{sub m}-based model. This indicates that even though a simple linear regression model is quite adequate for the near equatorial stations, where the temperature variations are relatively small, for estimating PW from GPS data at higher latitudes this model is inferior to the T{sub m}-based model. (orig.)

Suresh Raju, C.; Saha, K.; Thampi, B.V.; Parameswaran, K. [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

2007-07-01

28

Urinary conduits in gynecologic oncology  

Energy Technology Data Exchange (ETDEWEB)

Over an 11-year period (1971 to 1981), 212 urinary conduit surgeries were performed by the Department of Gynecology at the University of Texas, M. D. Anderson Hospital and Tumor Institute at Houston. The urinary diversions were performed as part of the pelvic exenteration operation in 154 patients, for radiation injury in 48 patients, and for palliation of disease recurrence in ten patients. Ninety-three percent had prior pelvic radiotherapy. Various segments of the gastrointestinal tract were used, including the ileum (102), sigmoid colon (99), transverse colon (four), jejunum (four), and others (three). Fifty percent of abnormal preoperative intravenous pyelograms reverted to normal after urinary diversion. Revision of the stoma was required in 6%. Other complications included infection (18%), renal loss (17%), and urinary leaks and fistulae (3%). The overall perioperative mortality was 7%, decreasing from 11% in the first five years to 3% during the last six years. Ureteral stents were routinely used. When selecting a segment of bowel for a urinary conduit, both tissue quality and mobility are important. Mortality and morbidity of urinary conduit surgery continues to decrease with experience.

Hancock, K.C.; Copeland, L.J.; Gershenson, D.M.; Saul, P.B.; Wharton, J.T.; Rutledge, F.N.

1986-05-01

29

Urinary conduits in gynecologic oncology  

International Nuclear Information System (INIS)

Over an 11-year period (1971 to 1981), 212 urinary conduit surgeries were performed by the Department of Gynecology at the University of Texas, M. D. Anderson Hospital and Tumor Institute at Houston. The urinary diversions were performed as part of the pelvic exenteration operation in 154 patients, for radiation injury in 48 patients, and for palliation of disease recurrence in ten patients. Ninety-three percent had prior pelvic radiotherapy. Various segments of the gastrointestinal tract were used, including the ileum (102), sigmoid colon (99), transverse colon (four), jejunum (four), and others (three). Fifty percent of abnormal preoperative intravenous pyelograms reverted to normal after urinary diversion. Revision of the stoma was required in 6%. Other complications included infection (18%), renal loss (17%), and urinary leaks and fistulae (3%). The overall perioperative mortality was 7%, decreasing from 11% in the first five years to 3% during the last six years. Ureteral stents were routinely used. When selecting a segment of bowel for a urinary conduit, both tissue quality and mobility are important. Mortality and morbidity of urinary conduit surgery continues to decrease with experience

1986-01-01

30

Modified Bentall operation with a novel biologic valved conduit.  

UK PubMed Central (United Kingdom)

PURPOSE: The optimal conduit for a modified Bentall operation remains unknown. The current study tested hemodynamics and early clinical results of the newly developed valved conduit composed of the 3f Aortic Bioprosthesis (ATS Medical, Minneapolis, MN) and the Vascutek Gelweave Valsalva Aortic Root Graft (Terumo Cardiovascular Systems, Ann Arbor, MI). DESCRIPTION: Between December 1, 2008, and April 6, 2009, 20 patients underwent a modified Bentall operation with this valved conduit and their clinical records were retrospectively reviewed. EVALUATION: The indication for aortic root replacement in the 20 patients was aortic root aneurysm in 14, acute type A dissection in 5, and structural deterioration of an aortic root homograft in 1. Four patients had had previous cardiac operations, and 8 patients required concomitant procedures. Mean cardiopulmonary bypass and aortic cross-clamp times were 146 +/- 110 minutes and 110 +/- 32 minutes, respectively. There were no perioperative deaths. The average mean pressure gradient across the bioprosthesis assessed with intraoperative transesophageal echocardiogram was 4.0 +/- 1.7 mm Hg. CONCLUSIONS: Our initial experience with our new valved conduit showed favorable results. Further accumulation of cases and longer follow-up are warranted.

Stewart AS; Takayama H; Smith CR

2010-03-01

31

Ileal conduit post radical cystectomy: modifications of the technique.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Ileal conduit, post radical cystectomy, is currently the most practiced type of urinary diversion. The aim of our study was to modify the ileal conduit technique in order to retain acceptable outcomes while decreasing the rate of postoperative urine leak and ureteroileal stricture. METHODS: Forty consecutive patients were included in our study, from January to June 2011. Radical cystectomy and ileal conduit using our modifications were done for all the cases. Follow-up was done for one year. One patient with right pelvic kidney was added to the studied group and was managed by extra modification to our technique. RESULTS: The mean age of the patients was 63 years. No significant leak and no stricture were observed within the modest duration of follow-up. When a left upper urinary tract retrograde study was attempted in one patient, the left ureteric orifice could not be reached due to a redundant elongated ileum. CONCLUSIONS: Modified Bricker techniques are safe, avoid early postoperative urine leak, and lower the incidence of ureteroileal anastomotic stricture. Using our modifications, retrograde access of the left ureter may not be possible. The 'Z' ileal conduit is a feasible technique that can allow tension-free healthy ureteroileal anastomosis for cases with pelvic right kidney and, probably, post renal transplantation.

Kotb AF

2013-01-01

32

Ileal conduit post radical cystectomy: modifications of the technique  

Science.gov (United States)

Introduction: Ileal conduit, post radical cystectomy, is currently the most practiced type of urinary diversion. The aim of our study was to modify the ileal conduit technique in order to retain acceptable outcomes while decreasing the rate of postoperative urine leak and ureteroileal stricture. Methods: Forty consecutive patients were included in our study, from January to June 2011. Radical cystectomy and ileal conduit using our modifications were done for all the cases. Follow-up was done for one year. One patient with right pelvic kidney was added to the studied group and was managed by extra modification to our technique. Results: The mean age of the patients was 63 years. No significant leak and no stricture were observed within the modest duration of follow-up. When a left upper urinary tract retrograde study was attempted in one patient, the left ureteric orifice could not be reached due to a redundant elongated ileum. Conclusions: Modified Bricker techniques are safe, avoid early postoperative urine leak, and lower the incidence of ureteroileal anastomotic stricture. Using our modifications, retrograde access of the left ureter may not be possible. The ‘Z’ ileal conduit is a feasible technique that can allow tension-free healthy ureteroileal anastomosis for cases with pelvic right kidney and, probably, post renal transplantation.

Kotb, Ahmed Fouad

2013-01-01

33

The Contegra conduit: Late outcomes in right ventricular outflow tract reconstruction.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To report the clinical outcomes (early death, late death, and rate of reintervention) and performance of the Contegra conduit as a right ventricle outflow tract implant and to determine the risk factors for early reintervention. METHODS: Forty-nine Contegra conduits were implanted between January 2002 and June 2009. Data collection was retrospective. The mean age and follow-up duration of Contegra recipients was 3.5 ± 4.6 years and 4.2 ± 2.0 years, respectively. RESULTS: There were three deaths (two early, one late), giving a survival rate of 93.9%. The rate of conduit-related reintervention was 19.6% and was most often due to distal conduit stenosis. Age at implantation of <3 months, receipt of a conduit of 12-16 mm diameter, and a diagnosis of truncus arteriosus were each significant contributors to the rate of reintervention. CONCLUSION: The Contegra is a cost-effective and readily available solution. However, there is a limited range of larger calibers, which means that the homograft conduit (>22 mm) remains the first choice of implant in older children. The rates of reintervention are significantly higher with a diagnosis of truncus arteriosus, age at implantation of <3 months, and implantation of conduits sized 12-16 mm.

Holmes AA; Co S; Human DG; Leblanc JG; Campbell AI

2012-01-01

34

Right ventricle to pulmonary artery conduit reoperations in patients with tetralogy of fallot or pulmonary atresia associated with ventricular septal defect.  

UK PubMed Central (United Kingdom)

The short lifespan of right ventricle-to-pulmonary artery (RV-PA) conduits used in repairs of complex congenital heart defects makes future surgical replacement inevitable. Percutaneous pulmonary valve implantation (PPVI) now offers an attractive alternative to surgery in some patients. The objectives of this study were to examine the pattern of conduit reoperations, the factors affecting conduit longevity, and to discuss the role of PPVI in these patients. Forty-nine patients (mean age 27 ± 8 years) with pulmonary atresia or pulmonary stenosis with tetralogy of Fallot who underwent surgery for RV-PA conduits from September 1974 to October 2011 were reviewed. A total of 106 RV-PA conduits were implanted, 57 of which were replacements. Second, third, and fourth conduits were required during the follow-up period in 39, 16, and 2 patients, respectively. Freedom from reoperation at 10 years for the first, second, and third conduits was 50%, 74%, and 86%, respectively. Significant independent predictors of shorter conduit longevity included smaller conduit and conduit type (homograft and other vs Dacron). Furthermore, a significant proportion (32 of 57 [56%]) of conduit replacements took place from ages 9 to 18 years. There were 37 adults whose current existing conduits had not yet failed, with 73% (27 of 37) potentially suitable in the future for PPVI on the basis of conduit size of 16 to 27 mm. In conclusion, multiple RV-PA conduit revisions were required in patients who survived to adulthood, with many replacements taking place during adolescence. Most conduits in this adult cohort met size criteria for PPVI, thereby offering these patients a potential alternative to surgical intervention for conduit failure.

Ong K; Boone R; Gao M; Carere R; Webb J; Kiess M; Grewal J

2013-06-01

35

A conduit to amplify innate immunity.  

UK PubMed Central (United Kingdom)

In this issue of Immunity, Py et al. (2013) report that upon bacterial infection, a fragment of the matrix protein cochlin is released from the conduits of B cell follicles to trigger protective cytokines in the periphery.

Moussion C; Sixt M

2013-05-01

36

Small hydro conduit optimization with differential calculus  

Energy Technology Data Exchange (ETDEWEB)

Differential calculus methods were used to simplify the calculation of optimizing a power plant conduit. An equation for the costs and lost benefits as a function of conduit diameter was proposed. A nine-step procedure was presented which included a method to take into account different operating modes, peaking or base loaded. Two working examples, one based on a proposed power plant in the Northwest Territories and one on a high pressure steel penstock in South America were presented. 5 refs.

Gordon, J.L.

1998-05-01

37

Injection control device for subterranean well conduit  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a valving mechanism for a well conduit communicating with a downhole tool comprising: a hollow valve housing connected in series relationship with the well conduit; a slip joint connected in series relationship with the well conduit intermediate the hollow valve housing and the downhole tool; whereby the hollow valve housing may be shifted axially by the well conduit moving the downhole tool; a first annular valve element sealingly mounted within the bore of the hollow valve housing and axially shiftable with the valve housing, a support rod insertable within the bore of the hollow valve housing to define an annular fluid passage therebetween. A second annular valve element is sealingly mounted on the exterior of the support rod, whereby axial movement of the valve housing in one direction moves the first and second valve elements into axially abutting engagement to close the annular fluid passage, thereby preventing fluid flow through the conduit to the downhole tool. Axial movement of the valve housing in the opposite direction axially separates the first and second valving elements and permits fluid flow from the conduit to the downhole tool.

Ross, R.J.; Klumpyan, J.N.

1987-03-10

38

Mechanical cleaning of oil spills in seawater using circular conduits  

Energy Technology Data Exchange (ETDEWEB)

Treatment of the crude oil pollution in seawater has attracted global attention during the last two decades. This study was undertaken using circular conduits as a mechanical means to clean oil spills in seawater under different conditions of temperature, oil gravity, shaking frequency, conduit diameter, and initial thickness of oil layer. An experimental model was designed and built to achieve the study. It consists of shaking water bath (to represent sea waves) fitted with temperature controller and glass tubes of different inside diameters of 0.3 cm, 0.5 cm, and 0.7 cm. Three crude oils of different oil gravity of 35{sup o}API, 38{sup o}API, and 47{sup o}API were investigated under different shaking frequencies of 20, 40, and 60 stroke/minute with different tube diameters. The results proved that application of mechanical cleaning of oil spills using circular conduits is a practical technique. The cleaning of black oil spills is more efficient than one of volatile oil. Furthermore, the results indicated that the increase of shaking frequency and/or water temperature provide(s) faster cleaning of oil spills while temperature increase recovers the maximum oil. (Author)

Shedid, S.; Abou Kassem, J.; Zekri, A. [United Arab Emirates Univ., Al Ain City (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

2005-10-15

39

INLINE VAPORIZER  

UK PubMed Central (United Kingdom)

An inline vaporizer disposed in a carrier gas line vaporizes a fluid and adds such vaporized fluid to a carrier gas that flows within the carrier gas line. The vaporizer includes a reservoir or wick that transfers a fluid to a vaporizing element that is adjacent to the reservoir or wick. The vaporizer releases a vapor into the carrier gas he so that the carrier gas flows past the vaporizer to form a vapor and carrier gas mixture.

WEINSTEIN LAWRENCE A; CURRIE DOUGLAS H JR; SCOTT JAMES R; TRAN TUAN Q

40

MRI of the heart following implantation of a left ventricular apico-aortic conduit; Kernspintomografie zur umfassenden Untersuchung des Herzens nach Implantation von linksventrikulaeren apikoaortalen Conduits  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To investigate the potential of ECG-triggered MRI for the evaluation of postoperative anatomy and function of the heart and conduit following implantation of a left-ventricular apico-aortic conduit. Materials and Methods: 5 patients (2 female, 3 male, mean age 72.5 years) were examined using a 1.5 Tesla whole-body MRI (Gyroscan Intera, Philips Medical Systems, Best, The Netherlands) following apico-aortic conduit surgery due to severe aortic valve stenosis. The reason for performing conduit implantation instead of aortic valve replacement was the risk of injuring a bypass graft from prior coronary artery bypass surgery. Cine steady-state-free-precession (SSFP) sequences were used to assess ventricular function, navigator-gated 3D-SSFP and breath-hold, time-resolved contrast-enhanced MR angiography was used to display the postoperative anatomy, and 2D-gradient echo sequences with an inversion pulse to suppress the signal of the healthy myocardium were used to evaluate potential myocardial scarring. Flow sensitive gradient echo sequences were performed to determine the blood flow in the conduit. Results: In all patients the apico-aortic conduit proved to be open with a maximum flow velocity of 126 (+ 43) cm/s. The postoperative anatomy was able to be evaluated in all patients and perioperative myocardial infarction was able to be ruled out. The mean ejection fraction of the left ventricle was 44.2 + 6.2 % with a mean volume of 80 + 20.6 ml per heart beat. (orig.)

Ruhl, K.M.; Katoh, M.; Guenther, R.W.; Krombach, G.A. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Langebartels, G.; Autschbach, R. [Technische Hochschule Aachen (Germany). Klinik fuer Thorax-, Herz- und Gefaesschirurgie

2007-06-15

 
 
 
 
41

The conduit system of the lymph node.  

UK PubMed Central (United Kingdom)

The lymphoid compartment of lymph nodes is impermeable to many molecules that are delivered via afferent lymphatic vessels. In the lymphoid compartment, fibroblast reticular cells form an interconnected network-the conduit system. This network has a structural function supporting tightly packed lymphocytes and antigen-presenting cells; however, it also has an important function as a molecular sieve, since it contains tubules that are the only entry point for fluid and allow only small molecules and particles (including antigens) to flow along the network. This size exclusion may prevent pathogens entering the blood from lymph. Dendritic cells can sample antigens from the conduit system and present them to nearby lymphocytes; this may be particularly important in initiating immune responses. The importance of larger antigen transport via macrophages or other cells is unclear. Lymphocytes and antigen-presenting dendritic cells actively move and interact along the conduit system, perhaps in response to chemokines or cytokines transported by the conduit system; these molecules may also be transported to high endothelial venules and regulate the attraction of blood leukocytes to the lymph nodes. The conduit system is also important for fluid distribution between afferent lymphatics and blood, but the mechanisms are not yet established.

Roozendaal R; Mebius RE; Kraal G

2008-12-01

42

The conduit system of the lymph node.  

Science.gov (United States)

The lymphoid compartment of lymph nodes is impermeable to many molecules that are delivered via afferent lymphatic vessels. In the lymphoid compartment, fibroblast reticular cells form an interconnected network-the conduit system. This network has a structural function supporting tightly packed lymphocytes and antigen-presenting cells; however, it also has an important function as a molecular sieve, since it contains tubules that are the only entry point for fluid and allow only small molecules and particles (including antigens) to flow along the network. This size exclusion may prevent pathogens entering the blood from lymph. Dendritic cells can sample antigens from the conduit system and present them to nearby lymphocytes; this may be particularly important in initiating immune responses. The importance of larger antigen transport via macrophages or other cells is unclear. Lymphocytes and antigen-presenting dendritic cells actively move and interact along the conduit system, perhaps in response to chemokines or cytokines transported by the conduit system; these molecules may also be transported to high endothelial venules and regulate the attraction of blood leukocytes to the lymph nodes. The conduit system is also important for fluid distribution between afferent lymphatics and blood, but the mechanisms are not yet established. PMID:18824503

Roozendaal, Ramon; Mebius, Reina E; Kraal, Georg

2008-09-29

43

Control adaptativo para arranque de generadores de vapor mediante redes neuronales dinámicas/ STEAM GENERATORS START-UP BY MEANS OF AN ADAPTIVE CONTROL AND DYNAMIC NEURAL NETWORKS  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish En este documento se describe el modelado y el control adaptativo mediante redes neuronales auto-recurrentes para arranque de un generador de vapor, con el fin de disminuir el tiempo de arranque y minimizar las variaciones y fallas por ajuste manual de las variables involucradas en este proceso. La variable de proceso a controlar para el arranque, es principalmente la temperatura, además se controla el oxigeno para garantizar la máxima eficiencia de la combustión en lo (more) s quemadores. Ambas se controlan mediante la manipulación de la relación gas natural/aire de combustión. Los datos de entrenamiento son empíricos del proceso y son medidos cada 2 minutos. La simulación del proceso y del controlador se realizó en MATLAB. Las acciones de control resultantes concuerdan con un arranque normal del generador de vapor. Abstract in english In this document it will be explain the modeling and adaptive control by means of auto-recurrent neural networks for steam generators start-up with the purpose of obtain a minimum in the start-up time, the variance and the failures for manual settings of the process variables. The primary start-up process variable to control is the temperature, but in addition will be control the oxygen for guarantee the maximum performance of the burner combustion. Both variables were co (more) ntrolled setting the relation between the natural gas and combustion air. The training data are empiric of the process and it was sampled every 2 minutes. The process and controller simulation was realized in MATLAB. The controller actions obtained in the simulations had concordance with a normal start up of the steam generator.

Aguirre, Miguel

2009-06-01

44

A case report of complication liked jejunal conduit syndrome induced by reconstruction of ileal conduit  

International Nuclear Information System (INIS)

The patient was a 77-year-old man who underwent radical cystectomy and ileal conduit urinary diversion due to bladder cancer in 1989. A stenosis of the right uretero-ileal anastomosis occurred in 1992, and of the left uretero-ileal anastomosis in 1999. These were treated with indwelling of a ureteral stent and percutaneous nephrostomy, respectively. He was admitted to our hospital for progressive renal dysfunction due to frequent pyelonephritis. We performed a reconstruction of the ileal conduit urinary diversion and after the removal of the bilateral ureteral stent he complained of nausea and general malaise. The laboratory data showed hyponatremia, hyperkalemia and azotemia, which were diagnosed as complication liked jejunal conduit syndrome. He was treated with hydration and salt supplementation. With regard to this case, we considered that a long ileal conduit close to the jejunum and renal dysfunction caused the complication liked jejunal conduit syndrome. Careful observation and follow-up laboratory examination should be performed if the patient has renal dysfunction and a long conduit near the jejunum is used for the ileal conduit. (author)

2004-01-01

45

A new aortic Dacron conduit for surgical treatment of aortic root pathology.  

UK PubMed Central (United Kingdom)

BACKGROUND: This article describes a new aortic Dacron conduit that has been designed for use in all types of surgery of the aortic root. Its use is aimed at facilitating the surgical procedure and obtaining a natural anatomical configuration of the aortic root. METHODS: The modified Dacron conduit is obtained by adding a smaller piece of Dacron tube that is resilient in the horizontal plane to one end of a standard Dacron conduit. Upon implantation, this small piece of Dacron conduit will stretch in the horizontal plane creating pseudosinuses and a new sinotubular junction. This modified conduit has been used in 4 cases for a Bentall operation in association with a mechanical or a biological valve, in 4 cases in a Yacoub type of valve sparing procedure and in 1 case in a David type I of valve sparing procedure. All patients had aortic root aneurysm with severe aortic regurgitation. There were 6 males and 3 females with a mean age of 61 +/- 16 years. In most cases a 28 mm Dacron conduit was used. RESULTS: All surgery was carried out without mortality or morbidity. The creation of pseudosinuses was confirmed intraoperatively by visual inspection. Transesophageal echocardiography in patients who had undergone the Bentall operation showed a normally functioning valve prosthesis with a suitably shaped aortic root. In patients who had undergone the valve sparing procedures it showed a competent aortic valve, the creation of pseudosinuses of normal shape and depth, and the presence of a well defined sinotubular junction. Angiography confirmed that the prosthetic aortic root perfectly resembled the normal root anatomy. CONCLUSIONS: This modified new aortic root conduit appears to perfectly reproduce a normal root anatomy without the need of modifying the original techniques.

De Paulis R; De Matteis GM; Nardi P; Scaffa R; Colella DF; Chiarello L

2000-07-01

46

Phase distribution in complex geometry conduits  

International Nuclear Information System (INIS)

Bubbly air/water two-phase flow data have been taken as an isosceles triangle using hot film probes. It was found that a 3-D two-fluid model was able to predict these data and those taken previously in circular conduits. It appears that mechanically-based CFD predictions of bubbly two-phase flows is possible for many cases of practical concern. (orig.)

1993-01-01

47

Arterial conduits for distal upper extremity bypass.  

UK PubMed Central (United Kingdom)

Vascular bypass is an accepted surgical procedure for treatment of hand and digital ischemia that is the result of identifiable arterial disease. Although vein grafts have traditionally been used as vascular conduits for reconstruction, arterial grafts present a better alternative, physiologically, for reconstruction and may result in superior outcomes. Arteries suitable for grafts are not abundant and, therefore, upper extremity surgeons must be informed about possible donor sites and techniques for harvest.

Masden DL; McClinton MA

2013-03-01

48

High temperature lined conduits, elbows and tees  

Energy Technology Data Exchange (ETDEWEB)

A high temperature lined conduit comprising, a liner, a flexible insulating refractory blanket around and in contact with the liner, a pipe member around the blanket and spaced therefrom, and castable rigid refractory material between the pipe member and the blanket. Anchors are connected to the inside diameter of the pipe and extend into the castable material. The liner includes male and female slip joint ends for permitting thermal expansion of the liner with respect to the castable material and the pipe member. Elbows and tees of the lined conduit comprise an elbow liner wrapped with insulating refractory blanket material around which is disposed a spaced elbow pipe member with castable refractory material between the blanket material and the elbow pipe member. A reinforcing band is connected to the elbow liner at an intermediate location thereon from which extend a plurality of hollow tubes or pins which extend into the castable material to anchor the lined elbow and permit thermal expansion. A method of fabricating the high temperature lined conduit, elbows and tees is also disclosed which utilizes a polyethylene layer over the refractory blanket after it has been compressed to maintain the refractory blanket in a compressed condition until the castable material is in place. Hot gases are then directed through the interior of the liner for evaporating the polyethylene and setting the castable material which permits the compressed blanket to come into close contact with the castable material.

De Feo, Angelo (Passaic, NJ); Drewniany, Edward (Bergen, NJ)

1982-01-01

49

Intake means of internal combustion engine  

Energy Technology Data Exchange (ETDEWEB)

An induction system is described for an internal combustion engine comprising: a first bank of cylinders; a second bank of cylinders disposed at an angle to the first bank of cylinders; a first air box defining a plenum chamber having a substantial volume juxtaposed to the first bank; a second air box defining a plenum chamber having a substantial volume juxtaposed to the second bank; means of admitting air to the air boxes; first conduit means extending from each of the air boxes to intake passage means of each cylinder of the juxtaposed cylinder bank; and second conduit means extending from each of the air boxes to intake passage means of each cylinder of the other of the cylinder banks, the second conduit means having a substantially longer effective length than the first conduit means.

Ohmi, M.; Yoneda, T.; Uchiyama, K.

1987-03-17

50

Anesthetic-vapor delivery apparatus with an ambient-referenced pressure regulator  

UK PubMed Central (United Kingdom)

A carrier gas source is connected to the breathing system of a patient by a carrier-gas conduit. A positive displacement gas pump has an outlet connected to a distal port in the carrier-gas conduit. A pump gas-supply conduit, includes a vaporizer chamber and an ambient-referenced pressure regulator which has an output orifice connected indirectly to the positive displacement pump inlet. In one kind of anesthetic-vapor delivery apparatus, for use with high boiling anesthetic agents, the pump gas-supply conduit has an input end connected to a proximal port in the carrier-gas conduit. In another kind of anesthetic-vapor delivery apparatus, for use with lower temperature anesthetic agents there is no proximal port. In both kinds of anesthetic-vapor delivery apparatus, the ambient-referenced regulator controls the pressure at the pump inlet to a narrow range of pressures just below ambient atmospheric pressure. A microprocessor may control the speed of the positive displacement pump for delivery of anesthetic at a chosen and accurately controlled rate. These anesthetic-vapor delivery apparatuses hold the anesthetic-vapor pressure at the inlet of the positive displacement pump to just below the ambient pressure in which the apparatus is being employed, and consequently hold constant the vapor pressure of anesthetic agent being delivered to the patient regardless of the ambient pressure and in spite of variations in the carrier gas pressure attributable to the patient's breathing system.

RUSZ TIBOR

51

Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005  

Science.gov (United States)

This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by modifying horizontal conductances assembled by the Block-Centered Flow (BCF), Layer-Property Flow (LPF), or Hydrogeologic-Unit Flow Packages (HUF) of MODFLOW-2005. For both conduit flow pipes (CFPM1) and preferential flow layers (CFPM2), critical Reynolds numbers are used to determine if flow is laminar or turbulent. Due to conservation of momentum, flow in a laminar state tends to remain laminar and flow in a turbulent state tends to remain turbulent. This delayed transition between laminar and turbulent flow is introduced in the CFP, which provides an additional benefit of facilitating convergence of the computer algorithm during iterations of transient simulations. Specifically, the user can specify a higher critical Reynolds number to determine when laminar flow within a pipe converts to turbulent flow, and a lower critical Reynolds number for determining when a pipe with turbulent flow switches to laminar flow. With CFPM1, the Hagen-Poiseuille equation is used for laminar flow conditions and the Darcy-Weisbach equation is applied to turbulent flow conditions. With CFPM2, turbulent flow is approximated by reducing the laminar hydraulic conductivity by a nonlinear function of the Reynolds number, once the critical head difference is exceeded. This adjustment approximates the reductions in mean velocity under turbulent ground-water flow conditions.

Shoemaker, W. Barclay; Kuniansky, Eve L.; Birk, Steffen; Bauer, Sebastian; Swain, Eric D.

2007-01-01

52

System and method measuring fluid flow in a conduit  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.

Ortiz, Marcos German (Idaho Falls, ID); Kidd, Terrel G. (Blackfoot, ID)

1999-01-01

53

Measurement of the friction of thin films by means of a quartz microbalance in the presence of a finite vapor pressure  

International Nuclear Information System (INIS)

In recent years, the quartz-crystal microbalance technique (QCM) has been succesfully applied to the field of nanotribology. In this paper we examine the effect of a finite vapor pressure on the accuracy of thin-film friction measurements taken with a QCM by solving the Navier-Stokes equation of the combined system quartz-crystal-adsorbed film-bulk vapor. We also discuss the details of the calibration procedure of the QCM carried out at both room temperature and low temperature, and describe the data acquisition and analysis specific to tribological applications. Finally, we present some preliminary data of the friction of a Kr monolayer adsorbed on gold at low temperatures that show the sliding of the film

2001-06-15

54

Measurement of the friction of thin films by means of a quartz microbalance in the presence of a finite vapor pressure  

Energy Technology Data Exchange (ETDEWEB)

In recent years, the quartz-crystal microbalance technique (QCM) has been succesfully applied to the field of nanotribology. In this paper we examine the effect of a finite vapor pressure on the accuracy of thin-film friction measurements taken with a QCM by solving the Navier-Stokes equation of the combined system quartz-crystal-adsorbed film-bulk vapor. We also discuss the details of the calibration procedure of the QCM carried out at both room temperature and low temperature, and describe the data acquisition and analysis specific to tribological applications. Finally, we present some preliminary data of the friction of a Kr monolayer adsorbed on gold at low temperatures that show the sliding of the film.

Bruschi, L.; Mistura, G.

2001-06-15

55

How to quantify conduits in wood?  

UK PubMed Central (United Kingdom)

Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

Scholz A; Klepsch M; Karimi Z; Jansen S

2013-01-01

56

How to quantify conduits in wood?  

Science.gov (United States)

Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology. PMID:23507674

Scholz, Alexander; Klepsch, Matthias; Karimi, Zohreh; Jansen, Steven

2013-03-18

57

Laparoscopic cystectomy and ileal conduit: case report.  

UK PubMed Central (United Kingdom)

A completely new combined laparoscopic cystectomy and ileal conduit technique for removal of an infiltrating bladder cancer was carried out on a 64-year-old woman. The bladder was dissected free and extracted whole through the right flank. The right ureter and a loop of intestine were withdrawn through the same incision. An ileal segment was isolated and intestinal continuity restored. The right ureter was anastomosed to one extreme of the segment that was then reintroduced into the abdomen, taken across to the left side, withdrawn with the left ureter, anastomosed extracorporeally, and reintroduced. The stoma was constructed in the left flank at the patient's request. Recuperation was unusually fast and painless, and little postoperative analgesia was required. Further experience and a two-team approach could reduce the operation time to 3 or 4 hours. We are now convinced that combining the two procedures was better for the patient, even though it prolonged the time in the operating room.

Sánchez de Badajoz E; Gallego Perales JL; Reche Rosado A; Gutierrez de la Cruz JM; Jimenez Garrido A

1995-02-01

58

[Radical cystectomy and laparoscopic ileal conduit  

UK PubMed Central (United Kingdom)

Herein we describe for the first time a laparoscopic cystectomy procedure and an ileal conduit that were performed in a single session in a patient with a tumor infiltrating the right wall. The procedure starts by releasing the ureters from the iliac junction up to a point close to the bladder. The peritoneum is incised superiorly at the level of the urachus and we proceed until the space of Retzius and the lateral walls are released. The vesicouterine plica is then incised and the bladder wings are dissected with the Endo-GIA. With a straight dissector, the urethra is released and cut until the bladder is completely free within the abdominal cavity. The trocar is removed from the right flank, the incision is extended up to about 4 cms and the bladder is removed. The right ureter and an ileal loop are then brought out through the incision on the right flank. A segment of intestine is isolated and intestinal continuity is reestablished using mechanical sutures. Then the ureter is implanted at one end of the isolated intestinal segment. The other end of the segment of intestine is taken to the left flank and anastomosed extracorporeally in a similar manner to the ureter of that side. The ileal conduit is positioned transversely so it is unnecessary to take the ureter to the opposite side. Finally, a stoma is created, which the patient desired done in the left side, and the procedure is completed. Although the operating time is long, the surgical insult is minimal because the McBurney type flank incisions cause little injury to the abdominal wall.

Sánchez de Badajoz E; Gallego Perales JL; Reche Rosado A; Gutiérrez de la Cruz JM; Jiménez Garrido A

1993-09-01

59

METHOD AND APPARATUS FOR MONITORING STRESS LEVELS OR SUDDEN CHANGES OF HUMOR IN HUMANS OR OTHER INDIVIDUALS IN REAL TIME BY MEANS OF VAPOR ANALYSIS  

UK PubMed Central (United Kingdom)

A method is described to perform on-line detection of stress levels or changes in humor of individuals. The approach is particularly advantageous because analysis can be performed in real time or, at least, comprising a delay shorter than 30 s, and because it is non-invasive and non-degrading and actually the individual under study do not need to be aware of being studied. More specifically, the present invention is based on the analysis of lactic acid and other volatiles concentrations in the vapors released by the individual (through the skin and the breath). The inventors have proved that said concentrations respond nearly instantaneously when the individual is subjected to a sudden stressful stimulus.

BORRAJO-PELAEZ RAFAEL; CRIADO-HIDALGO ERNESTO; VIDAL-DE-MIGUEL GUILLERMO

60

Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor  

Energy Technology Data Exchange (ETDEWEB)

The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

Chacon Nava, Jose G.; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1987-12-31

 
 
 
 
61

Mitrofanoff continent catheterizable conduits: top down or bottom up?  

UK PubMed Central (United Kingdom)

OBJECTIVE: During augmentation and Mitrofanoff procedures, conduits are usually implanted into the posterior bladder wall. Anatomical considerations may necessitate an anterior conduit. To compare the relative drainage efficiency in patients with posterior and anterior conduits, we studied their rates of bladder stone formation and urinary tract infection (UTI). MATERIALS AND METHODS: A retrospective chart review identified exstrophy patients who underwent augmentation and Mitrofanoff between 1991 and 2003. Patients with 3 years or greater follow-up were included. Fifty-four patients fit this criterion, with a conduit implanted anteriorly (33) or posteriorly (21). We compared rates of bladder stone formation and UTI. Stomal revisions and the status of the bladder neck were also noted. RESULTS: Stone formation and UTI rates were higher in the anterior conduits, although only UTI showed a statistically significant difference. Patient demographics were similar between the two groups, including age and sex. The rates of stomal complications and the bladder neck status were also similar. CONCLUSIONS: Patients with anterior conduits had an increased risk of UTI and bladder stone formation compared to those with posterior conduits, although this was not significant in the case of bladder stone rate. This may indicate sub-optimal bladder drainage and should be addressed with careful preoperative counseling and close follow-up.

Berkowitz J; North AC; Tripp R; Gearhart JP; Lakshmanan Y

2009-04-01

62

Characterisation of xylem conduits and their possible role in limiting the vase life of cut Acacia holosericea (Mimosaceae) foliage stems  

UK PubMed Central (United Kingdom)

Early desiccation limits the vase life of Acacia cut flowers and foliage and may be attributable to poor hydraulic conductivity (Kh) of the cut stems. Acacia holosericea A.Cunn. ex G.Don has been adopted as the test species to investigate the postharvest water relations of the genus Acacia. To understand potential constraints on Kh, xylem conduits in cut A. holosericea stems were anatomically characterised by light and scanning and transmission electron microscopy. Vessels with simple perforation plates and tracheids were the principal water conducting cells. Bordered vestured intervessel pits were present in xylem vessel elements. The majority of conduits (89%) were short at 1-5cm long. Only 2% were 15-16cm in length. Mean xylem conduit diameter was 77±0.9µm and the diameter profile showed a normal distribution, with 29% of diameters in the range of 70-80µm. Simple perforation plates can offer relatively low resistance to water flow. On the other hand, bordered vestured pits and short xylem conduits can confer comparatively high resistance to water flow. Overall, the presence of bordered vestured pits, together with a high proportion of short xylem conduits and high stomatal densities (232±2mm-2) on unifacial phyllodes, could contribute to early dehydration of A. holosericea cut foliage stems standing in vase water. Further research will relate these anatomical features with changes in Kh and transpiration of cut foliage stems.

Damunupola JilushiW; Ratnayake Kamani; Joyce DarylC; Irving DonaldE

2011-01-01

63

Use of collagen conduits in management of painful neuromas of the foot and ankle.  

UK PubMed Central (United Kingdom)

BACKGROUND: Painful neuromas of the foot and ankle frequently pose a treatment dilemma due to persistent pain or recurrence after resection. The purpose of this survey was to evaluate the clinical and functional outcomes in patients in which collagen nerve conduits were used as an adjunct to the resection of a painful neuroma. Our prior experience with vein conduits for this purpose suggested that we might have similar success with the use of these devices. MATERIALS AND METHODS: Chart reviews and telephone surveys were performed on patients operated by the senior surgeon (JSG) at our medical center from June 2006 to June 2011. A total of 50 patients underwent excision of painful single or multiple neuromas with the end of the resected nerve sutured into the collagen conduit. Each patient preoperatively was asked to describe the amount of pain he or she was experiencing on a scale from 1 to 10, with 10 indicating the most severe pain. In the telephone interview conducted during this study, the same question was asked of each patient following revision. Patient ages ranged from 16 to 77 years, with a mean of 54 years. In all, 30 right and 20 left sides were operated, and 1 patient had bilateral involvement. Mean follow-up was 36 months (6-55 months). There were a total of 69 nerves that underwent conduit procedures. RESULTS: Of 69 nerve conduit constructs, 30 (43%) were painless at final outcome, 23 (33%) had pain scores of 1 to 4, 6 (9%) had pain scores of 5 to 7, and 10 (15%) had severe symptoms with pain scores of 8 to 10. Satisfactory outcomes in which patients stated that they were significantly improved with the procedure and now functional occurred in 59/69 (85%). In all, 24 (48%) patients were completely symptom free, 13 (26%) had a pain score of 1 to 4, 6 (12%) had scores of 5 to 7, and 10 (15%) had severe pain with scores of 8 to 10. Three patients had superficial infections (stitch abscesses): 2 resolved with oral antibiotics and 1 resolved spontaneously. Three patients developed complex regional pain syndrome. One patient responded to a dorsal column stimulator and 2 responded to sympathetic blocks. No other complications were reported. CONCLUSION: Collagen conduits were safe and generally successful adjuncts to simple excision in the management of painful neuromas of the foot and ankle. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Gould JS; Naranje SM; McGwin G Jr; Florence M; Cheppalli S

2013-07-01

64

First 102 patients with the BioValsalva conduit for aortic root replacement.  

UK PubMed Central (United Kingdom)

BACKGROUND: We retrospectively evaluated our results with the BioValsalva Conduit (Vascutek Terumo, Renfrewshire Scotland), a stentless porcine valve incorporated in a 3-layered prosthetic graft. METHODS: From July 2008 through April 2011, 102 patients with a mean age of 70.9 ± 7.3 years underwent aortic root replacement with a BioValsalva conduit. The indication for surgery was aneurysmal disease of the aorta in 81 patients (79.4%), aortic valve endocarditis in 15 patients (14.7%), acute type A aortic dissection in 4 patients (3.9%), and other causes in 2 patients (2.0%). In 26 patients (25.5%), the intervention was a reoperation. RESULTS: Overall hospital mortality was 4.9% (n = 5; 95% confidence limit [CL], 1.6%-11.1%). Cause of death was cardiac failure in 2 patients, multiple organ or renal failure in 2 patients, and tamponade in 1 patient. Mean follow-up was 8.1 months. During follow-up, 3 deaths occurred (3.1%) because of mediastinitis, cardiac ischemia, and arrhythmia. The overall survival at 3 and 12 months was 95.9% (95% CL, 92.0% -99.9%) and 92.1% (95% CL, 85.7% -98.9%) respectively. Three patients (3.1%) had new-onset endocarditis of the BioValsalva conduit; 2 of these patients required reoperation and 1 patient received antibiotic treatment only. CONCLUSIONS: Retrospective analysis of the BioValsalva conduit for aortic root replacement in more than 100 consecutive patients demonstrated satisfactory initial results, with low mortality and acceptable low morbidity rates. Follow-up is mandatory and long-term results are to be awaited.

Kaya A; Heijmen RH; Kelder JC; Morshuis WJ

2012-07-01

65

Ileal-conduit following cystectomy, single-institution revision of indications and outcome  

International Nuclear Information System (INIS)

Objective was to revise indications, case fatality ratio, and postoperative early and late complications of ileal conduit as a method of urinary diversion. This is a retrospective study in which 200 patients underwent an ileal conduit from August 1994 to December 2000 in Mansoura Urology and Nephrology Center, Mansoura, Egypt. Preoperative criteria of patient selection, preoperative findings and postoperative follow-up data were reviewed. In 200 patients aged 29-75 years, with a mean age of 55.84-/+ 8.91 years, the ileal conduit was chosen as a method of urinary diversion, due to one of the following patient or surgical factors; 50 (25%) cardiopulmonary co-morbidities, 27(13.5%) liver cirrhosis, 20 (10%) impaired renal function, 18 (9%) poorly controlled diabetes mellitus and 3 (1.5%) morbid obesity. Frozen section pathological examination showed carcinoma invasion of the urethra in 26 (13%) and prostate stroma in 16 (8%) male patients. Severe adhesions and difficulty cystectomy were encountered in 25 (12.5%) patients. Tumor was found at or close to the bladder neck in 13 (6.5%) female patients and 2 (1%) patients were found to have short mesentery. The mean follow up period was 90.02 -/+ 22.63 months. Fatality rate was 2%. Twenty-three (11.5%) patients had early complications, while 36 (23.7%) patients had late complications. Ileal conduit is still the best urinary diversion method in many patients who have bladder cancer with associated chronic medical disease or certain surgical factors that render other urinary diversion methods more difficult carry more postoperative morbidity and mortality or both. (author)

2008-01-01

66

Computation of Uniform and Nonuniform Flow in Prismatic Conduits.  

Science.gov (United States)

Tables of geometric and hydraulic factors are presented for closed conduit shapes commonly encountered in water conveyance engineering. The tables provide for different degrees of resistance to flow resulting from different materials used in construction....

P. N. Zelensky

1972-01-01

67

[The preparation and evaluation of tissue inducible nerve guide conduit].  

UK PubMed Central (United Kingdom)

The objective of this research was to fabricate a novel tissue inducible nerve guide conduit, and to evaluate its biologic property. The microspheres were prepared with chitosan that encapsulated ligustrazine. The drug release of the chitosan microspheres was detected with application of the controlled release method in vitro. Chitosan microspheres were mixed with collagen to fabricate the tissue inducible nerve conduit, which were crosslinked with 2% genipin for 24h. Mechanical properties of the nerve guide conduit samples, including maximum load and breaking load, were measured using an Instron Series IX Automated Materials Testing System. The flexibility of the nerve guide conduit was determined with the texture evaluation instrument. Different methods, such as scanning electron microscope (SEM), light microscope (LMS) and immunofluorescence were used to analyze the spatial structure of the nerve guide conduit, the distribution of the microspheres, the state of the nerve duct combined with mesenchymal stem cells (MSCs), and the effect of the ligustrazine that released from chitosan microsphere on MSCs differentiation into nerve cells, respectively. The results showed that the chitosan microspheres had better releasing effect. The mechanical properties resultant nerve guide conduit were determined. The maximum load and breaking load of the genipin crosslinked samples were significantly higher than that observed with the non-crosslinkers, increasing to (0.76 +/- 0.15) N and (0.69 +/- 0.17) N from (0.23 +/- 0.09) N and (0.20 +/- 0.12) N for the non-crosslinkers (P < 0.01). The degradation rates of non-crosslinked and crosslinked by genipin were(58.62 +/- 7.59) mg and (9.23 +/- 2.47) mg, respec- tively. This had a statistical significance (P < 0.01). The average linearities in dry and hygrometric state of the nerve guide conduit were (0.597 +/- 0.012) LC and (0.333 +/- 0.015) LC, respectively, which also had statistical significance (P < 0.01). The flexibility in the hygrometric state of the nerve guide conduit was better than that of the dry. SEM analysis of the samples demonstrated that the structures of the nerve guide conduit were significantly changed in crosslinking samples, the microspheres were uniformly distributed on the surface of scaffold, the ligustrazine that released from the chitosan microspheres could promote MSCs to express NSE and MAP2 that were the relevant marker molecule of nerve cells. The nerve guide conduit is combined with MSCs, which promote MSCs proliferation and NSE expression by the ligustrazine that released from the chitosan microspheres. The conduit has better biological compatibility and tissue inducible function.

Zhao H; Liu X; Ge B; Guo C; Zhen P

2012-04-01

68

Superconducting cable-in-conduit low resistance splice  

Energy Technology Data Exchange (ETDEWEB)

A low resistance splice connects two cable-in-conduit superconductors to each other. Dividing collars for arranging sub-cable units from each conduit are provided, along with clamping collars for mating each sub-cable wire assembly to form mated assemblies. The mated assemblies ideally can be accomplished by way of splicing collar. The mated assemblies are cooled by way of a flow of coolant, preferably helium. A method for implementing such a splicing is also described.

Artman, Thomas A. (Forest, VA)

2003-06-24

69

Device for laying underground or digging up subsea conduits  

Energy Technology Data Exchange (ETDEWEB)

A self-propelling device for burying and digging up subsea conduits laid on beds of an incoherent material. The device has: disintegrating members using high pressure water jets to create a slurry of material, digging members having suction members which draw the suspension prepared by the disintegrating members, thus leaving a trench behind, and displacement members for moving the device on the seabed astride the conduit.

Berti, A.; Ilari, A.

1984-10-30

70

Neurotrophin releasing single and multiple lumen nerve conduits.  

UK PubMed Central (United Kingdom)

Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and processed by gas foaming. The porosity and mechanical properties of the constructs were regulated by the ratio of porogen to polymer microsphere. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing the protein with microspheres or encapsulating the protein within microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by method of incorporation and polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by its ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). In vivo results indicate that conduits retain their original architecture, and allow for cellular infiltration into the channels. Polymer conduits with controllable lumen diameters and protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth.

Yang Y; De Laporte L; Rives CB; Jang JH; Lin WC; Shull KR; Shea LD

2005-06-01

71

Neurotrophin releasing single and multiple lumen nerve conduits.  

Science.gov (United States)

Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and processed by gas foaming. The porosity and mechanical properties of the constructs were regulated by the ratio of porogen to polymer microsphere. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing the protein with microspheres or encapsulating the protein within microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by method of incorporation and polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by its ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). In vivo results indicate that conduits retain their original architecture, and allow for cellular infiltration into the channels. Polymer conduits with controllable lumen diameters and protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth. PMID:15911044

Yang, Yang; De Laporte, Laura; Rives, Christopher B; Jang, Jae-Hyung; Lin, Wei-Chun; Shull, Kenneth R; Shea, Lonnie D

2005-06-01

72

Comminution and frictional melting in volcanic conduits  

Science.gov (United States)

Shearing and faulting at active volcanoes may differ to tectonic faulting due to their distinct temperature conditions above those of the Earth's geotherm. In particular, the ascent of high-viscosity magma/rocks in upper conduits leads to shear/fault zones, with/without gouge formation and sometimes frictional melting; yet, details of the deformation and fracture mechanisms in these magma/rocks with different crystallinities reveal a different synopsis. For instance, the extrusion of lava domes proceeds endogenously or exogenically - a distinction generally understood as a shift in magma rheology to brittle failure, without consideration of the subsequent slip process. Exogenic growth and formation of a spine follow the dynamic rupture of the lava and the dome carapace, and suffer slip along the fault surface. Here, we present experimental investigations of the ability of volcanic rocks (with different glass/crystal and vesicle ratios) to sustain friction, and in cases melt, using a high-velocity rotary apparatus. During high-velocity rotary shear test, we find that slip of along andesite and basalt rocks generate heat which leads to frictional melting at temperature of ca. 1000 C, conciding to a total slip of 10-40 m (for slip initiating at room temperature). In contrast, slip along dense obsidian rocks or porous rocks cannot sustain slip along a discrete plane. Alternatively, obsidian can be slipped against a crystalline material. The width of the slip zone decreases in the presence of crystals. The findings suggest that the comminution of crystals is a requirement to the development of a localised slip zone. In absence of crystals, obsidian (and crystal-free magma) shatter catastrophically. We discuss the implication of our findings to the cases of tectonic faults, stability of volcanic edifices and evolution of lava dome eruptions.

Lavallee, Y.; Mitchell, T. M.; Heap, M. J.; Kendrick, J. E.; kennedy, B.; Ashwell, P. A.; Hirose, T.; Dingwell, D. B.

2011-12-01

73

Temperature limited heater with a conduit substantially electrically isolated from the formation  

Energy Technology Data Exchange (ETDEWEB)

A system for heating a hydrocarbon containing formation is described. A conduit may be located in an opening in the formation. The conduit includes ferromagnetic material. An electrical conductor is positioned inside the conduit, and is electrically coupled to the conduit at or near an end portion of the conduit so that the electrical conductor and the conduit are electrically coupled in series. Electrical current flows in the electrical conductor in a substantially opposite direction to electrical current flow in the conduit during application of electrical current to the system. The flow of electrons is substantially confined to the inside of the conduit by the electromagnetic field generated from electrical current flow in the electrical conductor so that the outside surface of the conduit is at or near substantially zero potential at 25.degree. C. The conduit may generate heat and heat the formation during application of electrical current.

Vinegar, Harold J. (Bellaire, TX); Sandberg, Chester Ledlie (Palo Alto, CA)

2009-07-14

74

Colonic conduit for esophageal replacement: long-term endoscopic and histopathologic changes in colonic mucosa.  

UK PubMed Central (United Kingdom)

BACKGROUND: Long-term follow-up has substantiated the colon as a durable and highly acceptable esophageal substitute. Exposure of colonic conduit to gastric acid may lead to histopathologic changes in the form of chronic inflammation. MATERIALS/METHODS: Thirty children with esophageal replacement were studied from 2 to 12 years (mean, 5.20 years) postoperatively. All cases underwent upper gastrointestinal tract endoscopy to evaluate the gross appearance of colonic conduit mucosa, and punch biopsies were taken from upper and lower junctions of the conduit. All biopsies were submitted to histopathologic examination. RESULTS: Endoscopic findings were comparable with normal regarding the gross appearance of colonic mucosa in both upper and lower junctions (25 cases/83.3%). Some abnormalities were seen including cervical anastomosis stricture (2 cases/6.7%), redundancy (3 cases/10%), mucosal ulcer in the lower residual esophagus (1 case/3.3%), and hyperemia (3 cases/10%). Pathologic changes were minimal regarding the change in position of the colon to a thoracic organ during follow-up. Most of the cases were normal (22 cases/73.3%). Seven cases (23.4%) showed mild chronic nonspecific inflammation of the colonic mucosa, whereas only 1 case (3.3%) showed mildly active inflammation of colonic mucosa. CONCLUSION: The use of the colon for esophageal replacement showed that no significant pathologic changes affecting its function as a conduit because its mucosa showed no significant change in response to gastric acid reflux in long-term follow-up and can be further protected by an antireflux procedure.

Elshafei H; Elshafei E; ElDebeiky M; Hegazy N; Zaki A; Abdel Hay S

2012-09-01

75

Injection control device for subterranean well conduit  

Energy Technology Data Exchange (ETDEWEB)

An injection control valve is described for treating a production formation of a subterranean well comprising packer means settable adjacent to the formation to be treated; a hollow mandrel extending upwardly from the packer means; an upwardly facing abutment surface on the packer means located within the mandrel; a hollow valve housing; slip joint means connecting the lower end of the valve housing to the upper end of the mandrel; means for connecting the upper end of the valve housing to a tubing string; a support rod axially traversing the valve housing and the mandrel and supported by the upwardly facing abutment surface. Also included is a description of the valving mechanism.

Ross, R.J.; Klumpyan, J.N.

1987-05-05

76

Thermomechanical milling of accessory lithics in volcanic conduits  

Science.gov (United States)

Accessory lithic clasts recovered from pyroclastic deposits commonly result from the failure of conduit wall rocks, and represent an underutilized resource for constraining conduit processes during explosive volcanic eruptions. The morphological features of lithic clasts provide distinctive 'textural fingerprints' of processes that have reshaped them during transport in the conduit. Here, we present the first study focused on accessory lithic clast morphology and show how the shapes and surfaces of these accessory pyroclasts can inform on conduit processes. We use two main types of accessory lithic clasts from pyroclastic fallout deposits of the 2360 B.P. subplinian eruption of Mount Meager, British Columbia, as a case study: (i) rough and subangular dacite clasts, and (ii) variably rounded and smoothed monzogranite clasts. The quantitative morphological data collected on these lithics include: mass, volume, density, 2-D image analysis of convexity (C), and 3-D laser scans for sphericity (?) and smoothness (S). Shaping and comminution (i.e. milling) of clasts within the conduit are ascribed to three processes: (1) disruptive fragmentation due to high-energy impacts between clasts or between clasts and conduit walls, (2) ash-blasting of clasts suspended within the volcanic flux, and (3) thermal effects. We use a simplified conduit eruption model to predict ash-blasting velocities and lithic residence times as a function of clast size and source depth, thereby constraining the lithic milling processes. The extent of shape and surface modification (i.e. rounding and honing) is directly proportional to clast residence times within the conduit prior to evacuation. We postulate that the shallow-seated dacite clasts remain subangular and rough due to short (<2 min) residence times, whereas monzogranite clasts are much more rounded and smoothed due to deeper source depths and consequently longer residence times (up to ˜1 h). Larger monzogranite clasts are smoother than smaller clasts due to longer residence times and to greater differential velocities within the ash-laden jet. Lastly, our model residence times and mass loss estimates for rounded clasts are used to estimate minimum attrition rates due to volcanic ash-blasting within the conduit (e.g., 12 cm3?s?1 for 25 cm clasts, sourced at 2500 m depth).

Campbell, Michelle E.; Russell, James K.; Porritt, Lucy A.

2013-09-01

77

Method for testing vapor recovery lines  

Energy Technology Data Exchange (ETDEWEB)

A method for testing the integrity of the vapor recovery unit of a gasoline station dispensing station where the vapor recovery unit has phase 11 capability is described, comprising the steps of: sealing the vapor recovery unit from the dispensing station at the point most proximal to the dispensing station; sealing the vapor recovery unit from the gasoline reservoir; installing means for drawing a vacuum in the riser of the vapor recovery unit; sealing the vent of the vapor recovery unit; drawing a vacuum in the sealed vapor recovery unit until the vacuum reaches a predetermined level; and monitoring the vacuum pressure relative to the predetermined level in the modified vapor recovery unit for a preselected period of time to determine whether the vapor recovery unit is leaking.

Tuma, J.E.

1993-06-22

78

Liquid-Vapor Coexistence in the Screened Coulomb (Yukawa) Hard Sphere Binary Mixture in Disordered Porous Media: The Mean Spherical Approximation.  

UK PubMed Central (United Kingdom)

The thermodynamics of a two-component fluid with a hard core interaction and screened Coulomb (Yukawa) interaction between particles, similar to the primitive model of an electrolyte solution, adsorbed in a disordered matrix of hard spheres, is studied by using replica Ornstein-Zernike integral equations and the mean spherical approximation (MSA). The gas-liquid transition is localized. The coexistence curve is investigated dependent on the range of interaction between fluid species, on matrix density, and on fluid-matrix attraction. We have observed shrinking of the coexistence envelope with increasing matrix density. The critical temperature of adsorbed mixture decreases with increasing matrix density. The critical density is less affected; however, it also decreases slightly. The critical temperature is sensitive to the fluid species-matrix attraction and depends nonmonotonously on their strength. For a given matrix microporosity, it increases slightly and then decreases with augmenting strength of fluid-matrix attraction. The critical density is less affected by this attraction. However, it decreases for the model with a sufficiently long-range tail of fluid-matrix attraction. Copyright 1998 Academic Press.

Trokhymchuk A; Orozco GA; Pizio O; Vlachy V V

1998-11-01

79

Effects of PVC conduits on sampling results of aerosol  

International Nuclear Information System (INIS)

[en] This paper presents the effects of PVC conduits on sampling results of aerosol. The MMAD of aerosol experimentally adopted is 7.1 ?m. Through 15 m PVC conduits with diameter of 30 mm and 50 mm, the concentration of aerosol decreased to 14.5% and 6.4% of the primary concentration respectively under laminar flow conditions, and to 21.3% and 15.4% under turbulence conditions. The aerosol size also changed, the mass fraction of particles of 4 ?m increases about 5 times. The method for determining the fraction of wall deposition is briefly introduced. The selection of sampling conduits and relevant aspects in application are also discussed

1988-01-01

80

Fluoroscopically guided balloon dilation or temporary stent placement for patients with gastric conduit strictures after esophagectomy with esophagogastrostomy.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The purpose of this study was to evaluate the clinical features of patients with gastric conduit strictures after esophagectomy and to report our initial experience in the management of these strictures with fluoroscopically guided balloon dilation, temporary stent placement, or both. MATERIALS AND METHODS: From January 1996 to January 2012, 12 patients with gastric conduit stricture after esophagectomy underwent fluoroscopic balloon dilation, temporary stent placement, or both. Stent placement was indicated in patients who had gastro-respiratory fistulas or recurrent symptoms within 2 weeks of balloon dilation. Technical and clinical success, complications, and length of strictures were retrospectively evaluated. RESULTS: The mean length of strictures in all patients was 49 mm (range, 21-76 mm). The strictures were accompanied by gastrorespiratory fistulas in four patients. Seven patients with gastric conduit strictures without fistulas underwent 23 balloon dilations. Five patients underwent stent placement owing to gastrorespiratory fistula formation (n = 4) and frequent recurrent symptoms after balloon dilation (n = 1). During a mean follow-up period of 8 months (range, 2-28 months), clinical success was achieved in 11 patients (91.6%) after a single balloon dilation (n = 1), multiple balloon dilations (n = 5), or stent placement (n = 5). Complications occurred in 3 of 10 patients (30%) after balloon dilation and in one of five patients (20%) after stent placement. CONCLUSION: Gastric conduit strictures are characterized by their substantial length and tend to be accompanied by gastrorespiratory fistulas. Despite relatively high complication and recurrence rates, this study may offer a viable treatment of gastric conduit strictures by using fluoroscopically guided balloon dilation and stent placement.

Lee J; Song HY; Ko HK; Park JH; Na HK; Kim YH; Jung HY

2013-07-01

 
 
 
 
81

Development of a scattering probability method for accurate vapor fraction measurements by neutron radiography  

CERN Document Server

Recent test results indicated drawbacks associated with the simple exponential attenuation method (SEAM) as currently applied to neutron radiography measurements to determine vapor fractions in a hydrogenous two-phase flow in a metallic conduit. The scattering component of the neutron beam intensity exiting the flow system is not adequately accounted for by SEAM, and this leads to inaccurate results. To properly account for the scattering effect, a neutron scattering probability method (SPM) is developed. The method applies a neutron-hydrogen scattering kernel to scattered thermal neutrons that leave the incident beam in narrow conduits but eventually show up elsewhere in the measurements. The SPM has been tested with known vapor (void) distributions within an acrylic disk and a water/vapor channel. The vapor (void) fractions deduced by SPM are in good agreement with the known exact values. Details of the scattering correction method and the test results are discussed.

Joo, H

1999-01-01

82

Development of a scattering probability method for accurate vapor fraction measurements by neutron radiography. Revision 1  

Energy Technology Data Exchange (ETDEWEB)

Recent test results indicated drawbacks associated with the simple exponential attenuation method (SEAM) as currently applied to neutron radiography measurements to determine vapor fractions in a hydrogenous two-phase flow in a metallic conduit. The scattering component of the neutron beam intensity exiting the flow system is not adequately accounted for by SEAM, and this leads to inaccurate results. To properly account for the scattering effect, a neutron scattering probability method (SPM) is developed. The method applies a neutron-hydrogen scattering kernel to scattered thermal neutrons that leave the incident beam in narrow conduits but eventually show up elsewhere in the measurements. The SPM has been tested with known vapor (void) distributions within an acrylic disk and a water/vapor channel. The vapor (void) fractions deduced by SPM are in good agreement with the known exact values. Details of the scattering correction method and the test results are discussed.

Joo, H.; Glickstein, S.S.

1998-11-01

83

Solvent vapor collector  

Science.gov (United States)

A solvent vapor collector is mounted on the upstream inlet end of an oven having a gas-circulating means and intended for curing a coating applied to a strip sheet metal at a coating station. The strip sheet metal may be hot and solvent vapors are evaporated at the coating station and from the strip as it passes from the coating station to the oven. Upper and lower plenums within a housing of the collector are supplied with oven gases or air from the gas-circulating means and such gases or air are discharged within the collector obliquely in a downstream direction against the strip passing through that collector to establish downstream gas flows along the top and under surfaces of the strip so as, in turn, to induct solvent vapors into the collector at the coating station. A telescopic multi-piece shroud is usefully provided on the housing for movement between an extended position in which it overlies the coating station to collect solvent vapors released thereat and a retracted position permitting ready cleaning and adjustment of that coating station.

Ellison, Kenneth (20 Avondale Cres., Markham, CA); Whike, Alan S. (R.R. #1, Caledon East, both of Ontario, CA)

1979-01-30

84

Growth of normal zones in cable-in-conduit superconductors  

Energy Technology Data Exchange (ETDEWEB)

A picture is proposed in which the growth of normal zones in cable-in-conduit superconductors is caused by the expansion of hot helium along the length of the conductor. Quantitative results suitable for experimental testing have been obtained by dimensional and similarity arguments. The results indicate non-uniform propagation at velocities of tens of meters per second.

Dresner, L.

1983-01-01

85

Evaluation of the MODFLOW-2005 Conduit Flow Process.  

UK PubMed Central (United Kingdom)

The recent development of the Conduit Flow Process (CFP) by the U.S. Geological Survey (USGS) provides hydrogeologic modelers with a new tool that incorporates the non-Darcian, multiporosity components of flow characteristic of karst aquifers. CFP introduces new parameters extending beyond those of traditional Darcian groundwater flow codes. We characterize a karst aquifer to collect data useful for evaluating this new tool at a test site in west-central Florida, where the spatial distribution and cross-sectional area of the conduit network are available. Specifically, we characterize: (1) the potential for Darcian/non-Darcian flow using estimates of specific discharge vs. observed hydraulic gradients, and (2) the temporal variation for the direction and magnitude of fluid exchange between the matrix and conduit network during extreme hydrologic events. We evaluate the performance of CFP Mode 1 using a site-scale dual-porosity model and compare its performance with a comparable laminar equivalent continuum model (ECM) using MODFLOW-2005. Based on our preliminary analyses, hydraulic conductivity coupled with conduit wall conductance improved the match between observed and simulated discharges by 12% to 40% over turbulent flow alone (less than 1%).

Hill ME; Stewart MT; Martin A

2010-07-01

86

Evaluation of the MODFLOW-2005 Conduit Flow Process.  

Science.gov (United States)

The recent development of the Conduit Flow Process (CFP) by the U.S. Geological Survey (USGS) provides hydrogeologic modelers with a new tool that incorporates the non-Darcian, multiporosity components of flow characteristic of karst aquifers. CFP introduces new parameters extending beyond those of traditional Darcian groundwater flow codes. We characterize a karst aquifer to collect data useful for evaluating this new tool at a test site in west-central Florida, where the spatial distribution and cross-sectional area of the conduit network are available. Specifically, we characterize: (1) the potential for Darcian/non-Darcian flow using estimates of specific discharge vs. observed hydraulic gradients, and (2) the temporal variation for the direction and magnitude of fluid exchange between the matrix and conduit network during extreme hydrologic events. We evaluate the performance of CFP Mode 1 using a site-scale dual-porosity model and compare its performance with a comparable laminar equivalent continuum model (ECM) using MODFLOW-2005. Based on our preliminary analyses, hydraulic conductivity coupled with conduit wall conductance improved the match between observed and simulated discharges by 12% to 40% over turbulent flow alone (less than 1%). PMID:20113361

Hill, Melissa E; Stewart, Mark T; Martin, Angel

2010-01-22

87

Growth of normal zones in cable-in-conduit superconductors  

International Nuclear Information System (INIS)

A picture is proposed in which the growth of normal zones in cable-in-conduit superconductors is caused by the expansion of hot helium along the length of the conductor. Quantitative results suitable for experimental testing have been obtained by dimensional and similarity arguments. The results indicate non-uniform propagation at velocities of tens of meters per second

1983-01-01

88

AC loss characteristics of simulated CIC-type conductors having plastic conduit  

International Nuclear Information System (INIS)

[en] When alternating current superconducting coils having cable-in-conduit conductors are fabricated, non-metallic conduit materials are necessary to avoid eddy current losses in the conduits. Using two kinds of non-metallic tapes made of glass fiber reinforced plastics (GFRPs) and Dyneema fiber reinforced plastics (DFRPs), we made the conductors with the GFRP conduits and DFRP conduits, and experimentally studied the total losses of the conductors. The measured results showed that the total loss of the conductor with the GFRP conduit was smaller than that with the DFRP conduit at the same value of the void ratio, the transport current, the external magnetic field, and so on. When the void ratios become high, the superconducting bundle cable can easily move in the conduit. Hence the measured total losses increased with the void ratios of the conductors

2003-01-01

89

AC loss characteristics of simulated CIC-type conductors having plastic conduit  

Energy Technology Data Exchange (ETDEWEB)

When alternating current superconducting coils having cable-in-conduit conductors are fabricated, non-metallic conduit materials are necessary to avoid eddy current losses in the conduits. Using two kinds of non-metallic tapes made of glass fiber reinforced plastics (GFRPs) and Dyneema fiber reinforced plastics (DFRPs), we made the conductors with the GFRP conduits and DFRP conduits, and experimentally studied the total losses of the conductors. The measured results showed that the total loss of the conductor with the GFRP conduit was smaller than that with the DFRP conduit at the same value of the void ratio, the transport current, the external magnetic field, and so on. When the void ratios become high, the superconducting bundle cable can easily move in the conduit. Hence the measured total losses increased with the void ratios of the conductors.

Kojo, Y.; Sekine, N.; Tada, S.; Yamaguchi, Y.; Obama, J.; Takao, T.; Miyagi, D.; Yamanaka, A

2003-10-15

90

Successful implantation of Thoratec assist device: wrapping of outflow conduit in Hemashield graft.  

UK PubMed Central (United Kingdom)

Persistent oozing and bleeding through the wall of the built-in outflow conduit in mechanical circulatory assist devices is a troublesome problem. Wrapping the outflow conduit of Thoratec in a Hemashield graft without preclotting completely prevents oozing and bleeding.

Minami K; Arusoglu L; Koyanagi T; el-Banayosy A; Körner MM; Körfer R

1997-09-01

91

Method and apparatus for removing the inner conduit from a dual passage drill string  

Energy Technology Data Exchange (ETDEWEB)

A method is described for removing the inner conduit from a dual conduit drill string used in drilling holes for geothermal, oil, and gas wells, and the like, to permit use of emergency or salvage procedures. It consists of: a. providing a standard drill pipe section; b. modifying the standard drill pipe section to form an interior support; c. engaging an inner conduit section with the interior support; d. joining the modified drill pipe sections at joints to form a drill pipe string; e. joining a plurality of the inner conduit sections at lockable joints to form an inner conduit string; f. locking the lockable inner conduit joints; and g. exerting an upward force on the inner conduit to remove the entire inner conduit string from the drill pipe string.

Reichman, J.M.; Mc Donald, M.C.; O' Brien, T.B.

1987-09-08

92

Repair of the peripheral nerve gap with epineural sheath conduit to prevent muscle denervation atrophy in the diabetic rat model.  

UK PubMed Central (United Kingdom)

Muscle denervation atrophy is a result of lower motor neuron injury, thus an early restitution of muscle stimulation is essential in prevention of atrophic changes. The aim of the study was to evaluate the new application of naturally occurring epineural sheath conduit in repair of the peripheral nerve gap to prevent development of muscle denervation atrophy. Material and methods. We used the model of 20 mm sciatic nerve gap, resulting in denervation atrophy of the gastrocnemius muscle in the diabetic rats (DM type 2, n=42, Zucker Diabetic Fatty strain). We applied the epineural sheath conduit created from the autologous sciatic nerve for gap repair. Muscle atrophy was assessed with the Gastrocnemius Muscle Index (GMI) and microscopic muscle morphometry (mean fiber area) at 6 and 12 postoperative week. Muscle regeneration in the experimental group was compared to the gold-standard technique of autologous nerve grafting for the repair of created nerve gap. Results. The GMI evaluation revealed comparable muscle mass restoration in groups with nerve repair using both epineural sheath and standard autologous nerve grafting (reaching 28 and 35% of contralateral muscle mass at 12 postoperative week, respectively, p=0.1), and significantly better restoration when compared to the negative control group (no repair, 20%, p<0.01). Micromorphometry confirmed significantly larger area of the regenerated muscle fibers in groups with both nerve grafting and epineural sheath conduit repair (reaching for both ca. 42% of the non-operated side), when compared to severe atrophic outcome when no nerve repair was performed (14% of the control fiber area, p<0.0001). The effectiveness of epineural conduit technique in muscle mass restoration was observed between 6 and 12 weeks after nerve repair - when gastrocnemius muscle mass increased by 12%. Conclusions. Peripheral nerve gap repair with naturally occurring epineural sheath conduit is effective in prevention of muscle denervation atrophy. This method is applicable in diabetic model conditions, showing results of regeneration which are comparable to the autologous nerve graft repair.

Lukaszuk M; Kwiecie? G; Madajka M; Uygur S; Drews M; Siemionow M

2013-07-01

93

Hyporheic exchange in a karst conduit and sediment system - A laboratory analog study  

Science.gov (United States)

Hyporheic flow in sediment filled karst conduits was studied using a laboratory analog model.Hyporheic flow is induced by conduits bends even for flat sediment surfaces.Zones of forwards and reserve flow occur in the sediments.Flow patterns can be reproduced by a dual domain model assuming pressure continuity.The exchange flux increases with increasing conduit flow rate and steepness of the conduit angle.

Wu, Yuexia; Hunkeler, Daniel

2013-09-01

94

A new simplified technique for making tricuspid expanded polytetrafluoroethylene valved conduit for right ventricular outflow reconstruction.  

UK PubMed Central (United Kingdom)

Several methods of making expanded polytetrafluoroethylene valved conduit have been reported, but these techniques are complicated and less reproducible. We have developed a new simplified technique for making a tricuspid expanded polytetrafluoroethylene valved conduit for right ventricular outflow tract reconstruction and have been using this conduit for approximately 3 years with excellent results. Our technique is straightforward and reproducible, and the cusps in the conduit are durable due to the use of a specialized suturing technique.

Kim H; Sung SC; Chang YH; Lee HD; Park JA

2013-05-01

95

Repair of a DN 600 industrial conduit at a black coal mine; Sanierung eines Industriekanals DN 600 auf einem Steinkohlebergwerk  

Energy Technology Data Exchange (ETDEWEB)

A conduit at a Gelsenkirchen mine had developed untightness of muffs and corrosion at the base. Conditions for repair works in the site were unfavourable. Trenchless repair was carried out by means of a tube relining method using PEHD sheeting. (orig.) [Deutsch] An einem Kanal innerhalb einer Zeche in Gelsenkirchen waren Muffenundichtigkeiten und Korrosion im Sohlbereich aufgetreten. Bei widrigen Baustellenbedingungen erfolgte die grabenlose Sanierung mit einem auf PEHD-Dichtungsbahnen basierenden Schlauchrelining-Verfahren. (orig.)

Schiffer, P.; Koelker, W.

1997-12-31

96

Long-term performance of the Hancock bioprosthetic valved conduit in the aortic root position.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess long-term morbidity and mortality with special regard to prosthesis durability after aortic root replacement with the Hancock bioprosthetic porcine conduit. METHODS: Between 1975 and 2004, a total of 81 patients (55 males, 26 females; mean age 58 +/- 18 years) underwent aortic root replacement with the Hancock conduit for aortic dissection (n = 22; 27%), ascending aortic aneurysm (n = 57; 70%), or porcelain aorta (n = 2; 3%). Twenty-five patients (31%) underwent an emergency operation, 12 (15%) presented with Marfan syndrome, and eight (10%) had undergone previous cardiac surgery. Concomitant procedures were performed in 26 cases (32%). The follow up was 98% complete; the mean follow up was 4.8 +/- 4.0 years (range: 1 day to 16.7 years), and the cumulative follow up was 403 patient-years. Actuarial event-free rates were calculated, and valve-related complications classified according to guidelines for reporting morbidity and mortality after cardiac valvular operations. RESULTS: There were seven (9%) operative deaths and four (5%) in-hospital deaths. Actuarial survival rates at five and 10 years (excluding operative deaths) were 77.0 +/- 5.3% and 54.0 +/- 7.5%, respectively. Actuarial freedom from aortic valve reoperation at five and 10 years was 98 +/- 1.6% and 64 +/- 10.2%, from structural valve deterioration 88.1 +/- 4.7% and 49.9 +/- 9.6%, from thromboembolic events 87.4 +/- 4.6% and 75.1 +/- 9.5%, and from major bleeding events 90.2 +/- 3.9% and 75.4 +/- 8.1%, respectively. Among redo procedures, the stentless Hancock valve could be excised without separating the synthetic graft from the left ventricular outflow tract, and a stented valve prosthesis thus implanted. Hence, it was possible to avoid a second Bentall operation. CONCLUSION: The long-term survival rates after aortic root replacement with the bioprosthetic Hancock conduit were reasonable for this demanding patient cohort. However, the durability of the prosthesis was inferior to that reported for the stented Hancock valve substitute. The key benefit of this bioprosthetic valved conduit was the simplified redo procedure.

Badiu CC; Bleiziffer S; Eichinger WB; Hettich I; Krane M; Bauernschmitt R; Lange R

2011-03-01

97

Quality of Life in Patients with Ileal Conduit Cystectomy Due to Bladder Cancer.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To determine the variables that affect quality of life of patients treated by radical cystectomy with ileal conduit. MATERIAL AND METHOD: We analyzed quality of life using the EQ-5D-3L questionnaire. This questionnaire evaluates mobility, personal care, daily activities, pain/discomfort, anxiety/depression and a self-rating scale of the health condition. We compared the result with demographic variables (gender, age, work situation, studies, income, partner) and clinical variables (ASA classification, tumor stage, time since cystectomy was performed, adjuvant chemotherapy, recurrent and complications of the stoma). The statistical analysis included a descriptive study, univariate and multivariate analysis. RESULTS: A total of 59 patients were included in the study, with a mean age of 69 years (47-84). Mean time from cystectomy was 43 months (12-83), with 61% complications associated to the stoma. Stoma complications were related with limitations in personal care, pain/discomfort, anxiety, depression and quality of life in general. Female gender was associated with limitations in daily activities and adjuvant chemotherapy with anxiety/depression and quality of life in general. The rest of the variables were not statistically significant in the multivariate analysis. CONCLUSIONS: The limitations in quality of life in patients with cystectomy and ileal conduit are associated with the stoma-associated complications. Other related variables are female gender and administration of adjuvant chemotherapy.

Tejido-Sánchez A; García-González L; Jiménez-Alcaide E; Arrébola-Pajares A; Medina-Polo J; Villacampa-Aubá F; Díaz-González R

2013-07-01

98

Assessment of the relationship between Contegra conduit size and early valvar insufficiency.  

UK PubMed Central (United Kingdom)

BACKGROUND: Contegra bovine jugular vein (BJV) conduit results vary widely, and little attention has been directed at assessment of early conduit insufficiency. Conduit insufficiency is graded subjectively, and criteria vary. Several studies have used branch pulmonary artery flow reversal (BPAFR) to define severe conduit insufficiency. BJV valves are larger than human pulmonary valves of similar diameter. We hypothesize that anatomic differences between BJV and human pulmonary valves limit the use of BPAFR in the evaluation of BJV competence. Our purposes were to (1) assess the prevalence of early and 6-month BJV conduit insufficiency in our patients, (2) determine if conduit size affects BJV competence, and (3) determine if BPAFR is a specific discriminator of severe conduit insufficiency. METHODS: We reviewed 135 BJV conduits. One cardiologist blinded to original reports reviewed postoperative and 6-month echocardiograms. Conduits were grouped by size: group 1, 12 to 14 mm (n=51), and group 2, 16 to 22 mm (n=84). Moderate or greater insufficiency was considered clinically significant. RESULTS: Early conduit insufficiency was common in group 1 (37%) and rare in group 2 (5%, p<0.0001). After excluding conduits with significant insufficiency, BPAFR occurred in 18% (group 1, 27%; group 2, 13%; p=0.02). At follow-up, insufficiency worsened in group 1 but was stable in group 2. CONCLUSIONS: Early conduit insufficiency is common and worsens with follow-up in small BJVs. Conduit insufficiency is limited in larger sizes and remains stable. BJV exhibits BPAFR commonly in the absence of significant conduit insufficiency. BPAFR should not be used as a primary criterion for grading insufficiency in BJV conduits.

Gist KM; Mitchell MB; Jaggers J; Campbell DN; Yu JA; Landeck BF 2nd

2012-03-01

99

CODUL EUROPEAN DE BUN? CONDUIT? ADMINISTRATIV? ?I FENOMENUL ADMINISTRATIV ROMÂNESC  

Directory of Open Access Journals (Sweden)

Full Text Available Pour vivre parmi les membres d¢une certaine collectivité humaine, il est absolument nécessaire de connaître et respecter les valeurs fondamentales de celle-ci. Il est nécessaire également de respecter et d’appliquer les lignes de conduite importées par les normes juridiques réglementant les relations sociales qui se forment dans la collectivité respective pour realiser et protéger ces valeurs. Le peuple roumain, étant impliqué dans la procedure d¢adhésion à l¢Union européenne, a le devoir de connaître le droit communautaire. Le législateur roumain a la mission d'élaborer et d'adopter des lois compatibles avec les normes juridiques communautaires. L'exécutif doit agir pour que les lois soient appliques par tous ceux qui l’exécutif vivent en Roumanie. Par couséquence, il est absolument nécessaire de réformer l'administration publique roumaine de sorte que la relation fonctionnaire public et autres agents de l'administration publique – citoyen destinataire et bénéficiaire de la décision administrative et de la prestation administrative, soit conforme aux standards de l'Union européenne. Cet ouvrage a comme but de présenter en quelle mesure les règles écrites dans le Code européen de bonne conduite administrative peuvent être un modèle pour le législateur roumain. Même si le Code européen de bonne conduite administrative est un document rédigé pour établir les principes généraux à observer dans les relations entre les institutions communautaires européennes et le public, nous considerons qu'il y a plusieurs raisons pour considérer ce Code comme un modèle digne d'être suivi dans l'activité du législateur roumain. Parmi ces raisons, se trouve la performance d'établir le contenu de la base légale pour la bonne conduite administrative utilisant seulement vingt-sept articles dans lesquels on précise les principes généraux pour ce domaine d'activité sociale. Donc, le caractère concis et pourtant explicite du texte est un modèle pour une loi roumaine concernant la bonne conduite administrative ou pour un chapitre du Code administratif, chapitre ayant comme sujet la bonne conduite administrative. Une autre raison est celle que des principes comme „légitimité”, „absence de discri­mination”, „la proportionnalité”, „absense d'abus de pouvoir”, „impartialité et indépendance”, „objectivité”, „équité”, „confiance légitime, cohérence et conseil” et „courtoisie” doivent être présents parmi les principes fondamentaux de l'administration publique, quel que soit le pays dont il s'agit.

Alina Nicu

2006-01-01

 
 
 
 
101

Dog tibial nerve regeneration across a 30-mm defect bridged by a PRGD/PDLLA/?-TCP/NGF sustained-release conduit.  

UK PubMed Central (United Kingdom)

Nerve conduits have emerged as alternatives to autologous nerve grafts, but their use in large-diameter, critical nerve repairs is limited. In the previous study, we prepared a PRGD/PDLLA/?-TCP/NGF sustained-release nerve conduit, which was made of RGD peptide modified poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PRGD), poly(d,l-lactic acid) (PDLLA), ?-tricalcium phosphate (?-TCP) and nerve growth factor (NGF). Here we attempted to use the PRGD/PDLLA/?-TCP/NGF sustained-release nerve conduit to bridge a 30-mm dog tibial nerve defect in six beagles. The other beagles were divided into group autograft (n = 6) as positive control and group PDLLA (n = 6) as negative control. After 9 months of implantation, nerve conduction velocities, the density of myelinated fibers, the mean diameter of axon, and the average thickness of myelin sheath in tibial nerves bridged with PRGD/PDLLA/?-TCP/NGF sustained-release nerve conduits were similar to those treated with autologous nerve (p > 0.05). Neither electrophysiological nor histological restoration was obtained in group PDLLA. Evidence is thus provided in support of the use of PRGD/PDLLA/?-TCP/NGF sustained-release nerve conduits as alternatives to autologous nerve grafts for treatment of large-diameter, critical defects in peripheral nerves.

Huang J; Xiang J; Yan Q; Li S; Song L; Cai X

2013-02-01

102

Studies on forced convection nanofluid flow in circular conduits  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental system was developed and used to study the nanofluid flow and heat transfer in circular conduits. Experiments were performed for a variety of nanofluid flow features in the system. Results obtained from the study show that the heat transfer rate for flow of the base fluid is less than that of the nanofluid used in the study. It was also found that the observed relationship between molecular diffusivity of momentum and the molecular diffusivity of thermal energy at the macroscale may not necessarily be the same at the nanoscale. A heat transfer correlation for turbulent forced convection flow in circular pipes was developed from the results in terms of Nusselt number, Reynolds number and Prandtl number. The correlation developed was compared to related correlations in the literature. Important factors that affect nanofluid flow and heat transfer in circular conduits were also determined. This type of study is essential for heat exchanger applications.

Harikrishna Vishwanadula; Emmanuel C. Nsofor

2012-01-01

103

High temperature packer for well conduits  

Energy Technology Data Exchange (ETDEWEB)

A packer for a subterranean well having a casing is described comprising, in combination, an inner tubular body assembly having connector means at its upper end for detachable threaded connection to the bottom of a tubing string whereby the packer may be run into the casing to a desired position; an outer operative tubing assembly mounted in surrounding relationship to a medial portion of the inner tubular body assembly. The outer tubular body assembly includes a drag block unit, a connection block, a slip mechanism including peripherally spaced slips and upper and lower cone elements, an external packing element having one end abutting the lower cone element and deformable by axial force to sealing engage the bore of the casing, and an annular abutment element engaging the other end of the packing element; a J-pin radially transversing the connecting block, a J-slot in the inner tubular body assembly receiving the J-pin for securing the inner tubular body assembly and the outer tubular operative assembly in a fixed relationship during run-in of the packer in the casing with only the drag block unit engaging the casing wall.

Preston, D.C. Jr.

1987-12-01

104

Early experience with crimped bovine pericardial conduit for arterial reconstruction.  

UK PubMed Central (United Kingdom)

A bovine pericardial conduit was developed in the laboratory incorporating the principle of crimping used for synthetic vascular prostheses. The pericardium was processed in glutaraldehyde and the tube was crimped by a technique which preserves the integrity of collagen fibres. This vascular substitute presents a non-thrombogenic and non-porous inner surface which does not require preclotting and does not leak. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The crimping design provides longitudinal elasticity and resistance to collapsing, retains its shape with bending and avoids kinking. Crimping provides a circular tube which makes the construction of the anastomosis easier. Experimental studies in dogs demonstrated absence of thromboembolism with the conduit implanted in the abdominal aorta. Fibrin accumulation was not noted in the convexities of the crimps. This conduit was designed for aortic and pulmonary reconstruction and available in different sizes with or without a biological valve. Initial clinical experience included its use in 10 patients with aortic dissections or aortic aneurysms from August 1989 to March 1990. A reconstruction of the abdominal aorta was performed in 2 patients, the descending thoracic aorta in 2, the ascending aorta in 2 and the ascending aorta including the aortic valve and reimplantation of coronary arteries in 4. For the latter 4, composite crimped pericardial tubes containing a porcine bioprosthesis were used. An additional patient with a single ventricle underwent a Fontan type operation also employing a valved crimped pericardial conduit.(ABSTRACT TRUNCATED AT 250 WORDS)

Salles CA; Puig LB; Casagrande IS; Vieira GL; Kalil RA; Souza LS; Andrade MA Jr

1991-01-01

105

Early experience with crimped bovine pericardial conduit for arterial reconstruction.  

Science.gov (United States)

A bovine pericardial conduit was developed in the laboratory incorporating the principle of crimping used for synthetic vascular prostheses. The pericardium was processed in glutaraldehyde and the tube was crimped by a technique which preserves the integrity of collagen fibres. This vascular substitute presents a non-thrombogenic and non-porous inner surface which does not require preclotting and does not leak. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The crimping design provides longitudinal elasticity and resistance to collapsing, retains its shape with bending and avoids kinking. Crimping provides a circular tube which makes the construction of the anastomosis easier. Experimental studies in dogs demonstrated absence of thromboembolism with the conduit implanted in the abdominal aorta. Fibrin accumulation was not noted in the convexities of the crimps. This conduit was designed for aortic and pulmonary reconstruction and available in different sizes with or without a biological valve. Initial clinical experience included its use in 10 patients with aortic dissections or aortic aneurysms from August 1989 to March 1990. A reconstruction of the abdominal aorta was performed in 2 patients, the descending thoracic aorta in 2, the ascending aorta in 2 and the ascending aorta including the aortic valve and reimplantation of coronary arteries in 4. For the latter 4, composite crimped pericardial tubes containing a porcine bioprosthesis were used. An additional patient with a single ventricle underwent a Fontan type operation also employing a valved crimped pericardial conduit.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1859668

Salles, C A; Puig, L B; Casagrande, I S; Vieira, G L; Kalil, R A; Souza, L S; Andrade, M A

1991-01-01

106

Association of Pulmonary Conduit Type and Size With Durability in Infants and Young Children.  

UK PubMed Central (United Kingdom)

BACKGROUND: Treatment of congenital heart disease may include placement of a right ventricle to pulmonary artery conduit that requires future surgical replacement. We sought to identify surgeon-modifiable factors associated with durability (defined as freedom from surgical replacement or explantation) of the initial conduit in children less than 2 years of age at initial insertion. METHODS: Since 2002, 429 infants were discharged from 24 Congenital Heart Surgeons' Society member institutions after initial conduit insertion. Parametric hazard analysis identified factors associated with conduit durability while adjusting for patient characteristics, the institution where the conduit was inserted, and time-dependent interval procedures performed after conduit insertion but before replacement/explantation. RESULTS: In all, 138 conduit replacements (32%) and 3 explantations (1%) were performed. Conduit durability at a median follow-up of 6.0 years (range, 0.1 to 11.7) was 63%. After adjusting for interval procedures and institution, placement of a conduit with smaller z-score was associated with earlier replacement/explantation (p = 0.002). Moreover, conduit durability was substantially reduced with aortic allografts (p = 0.002) and pulmonary allografts (p = 0.03) compared with bovine jugular venous valved conduits (JVVC). The JVVC were 12 mm to 22 mm in diameter at insertion (compared with 6 mm to 20 mm for allografts); therefore, a parametric propensity-adjusted analysis of patients with aortic or pulmonary allografts versus JVVC with diameter of 12 mm or greater was performed, which verified the superior durability of JVVC. CONCLUSIONS: Pulmonary conduit type and z-score are associated with late conduit durability independent of the effects of institution and subsequent interval procedures. Surgeons can improve long-term conduit durability by judiciously oversizing, and by selecting a JVVC.

Poynter JA; Eghtesady P; McCrindle BW; Walters HL 3rd; Kirshbom PM; Blackstone EH; Husain SA; Overman DM; Austin EH; Karamlou T; Lodge AJ; St Louis JD; Gruber PJ; Ziemer G; Davies RR; Jacobs JP; Brown JW; Williams WG; Tchervenkov CI; Jacobs ML; Caldarone CA

2013-08-01

107

Grading complication following radical cystectomy and ileal conduit for bladder cancer using clavien grading system  

International Nuclear Information System (INIS)

Objective: To determine the 30-day complication rate of radical cystectomy and urinary diversion using a validated system. Study Design: An analytical descriptive study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 1990 to 2010. Methodology: Patients who had undergone ileal conduit (IC) formation, following radical cystectomy (RC) for muscle invasive transitional cell carcinoma, were studied, using a prospectively maintained data base. Basic details were determined, complications were noted and graded according to the modified Clavien grading system (CG). Results were presented using descriptive statistics. Results: Of all the RC performed at this hospital 89 patients received IC. Of them 75 were male and 14 female. Mean age was 60 years. Mean duration of hospital stay was 14 days. Ten patients each received pre-operative chemotherapy and radiotherapy, respectively. Mean duration of surgery was 8.2 hours, with mean estimated blood loss of 1334 ml. Preoperative radiotherapy was associated with more complications. No other factor like ASA, co-morbidities, blood loss or duration of stay influenced the complications. Fifty patients (56.2%) did not have any complications. Most common complication of wound infection was seen in 7 patients (CG-2), followed by uretero-ileal leakage in 5, requiring percutaneous intervention under local anaesthesia (GC-3a). Mortality rate was 4.5%, classified as CG-V. Conclusion: Radical cystectomy with Ileal conduit is a major procedure with a good safety profile at this institute. Long term follow up is still needed to evaluate delayed complications and quality of life. (author)

2012-01-01

108

Mercury vapor bubble dynamics and vapor explosions  

International Nuclear Information System (INIS)

The current study of mercury vapor bubble dynamics was motivated by the Spallation Neutron Source being proposed at the Oak Ridge National Laboratory. According to recent research on vapor bubble dynamics with R-113, it was determined that under certain conditions, a growing vapor bubble can become unstable, with the liquid-vapor interface being rippled and corrugated, leading to dynamic growths, which can be characterized as vapor explosions. The question arises now as to whether a similar phenomena can take place with growing mercury vapor bubbles. If it occurs, what are the necessary conditions, and how might the behavior be controlled? This is the basis for this paper

1997-01-01

109

Mercury vapor bubble dynamics and vapor explosions  

Energy Technology Data Exchange (ETDEWEB)

The current study of mercury vapor bubble dynamics was motivated by the Spallation Neutron Source being proposed at the Oak Ridge National Laboratory. According to recent research on vapor bubble dynamics with R-113, it was determined that under certain conditions, a growing vapor bubble can become unstable, with the liquid-vapor interface being rippled and corrugated, leading to dynamic growths, which can be characterized as vapor explosions. The question arises now as to whether a similar phenomena can take place with growing mercury vapor bubbles. If it occurs, what are the necessary conditions, and how might the behavior be controlled? This is the basis for this paper.

Lee, Ho Sung; Merte, H. Jr. [Univ. of Michigan, Ann Arbor, MI (United States)

1997-12-01

110

Simultaneous trace determination of Hg(I)/Hg(II) or Hg(0)/Hg(I) and indirect determination of mercury complexing anions by means of cold-vapor-AAS  

Energy Technology Data Exchange (ETDEWEB)

The employment of the cold-vapor AAS for the species analysis of mercury has been tested. Interactions of Hg(II) with Hg(0) to Hg(I) on the one hand and with complexing anions on the other hand allow the following determinations: Hg(II) and Hg(I) in the same solution, Hg(0) in the air and in the presence of Hg(I), mercury complexing anions in a solution. The procedure depends on the fact that Hg(II) represses the vaporization of Hg(0) as a consequence of synproportionation. The vaporization is only possible after complexing the Hg(II). Two points of the absorption curve are important: the point of offset allows the calculation of Hg(II) and the absorption is proporional to the quantity of Hg(I). The ratio of Hg(II):Hg(I) has to be 2:1 (minimum). The determination limit is at the ppb-level.

Pinstock, H.; Umland, F.

1985-02-01

111

Imaging of platelets in right-sided extracardiac conduits in humans  

International Nuclear Information System (INIS)

As a connection between the systemic venous ventricle and the pulmonary artery, valved Dacron extracardiac conduits have remarkably influenced the surgical approach to many complex congenital heart defects. Obstruction of the conduit, however, can reduce the long-term effectiveness of this corrective procedure. In addition to stenosis of the porcine valve, formation of thick fibrous neointima plays a major role in the pathogenesis of conduit obstruction. The purpose of this study was to determine whether platelet deposition could be demonstrated in these conduits by external imaging with 111In-labeled autologous platelets. After injection of labeled platelets either immediately after operation or on the fifth to eighth postoperative day, imaging was performed by standard procedures. Eight of nine patients had platelet accumulation in the conduit, and treatment with aspirin and dipyridamole caused no recognizable change in platelet deposition. This study demonstrates the feasibility of imaging platelet deposition in Dacron conduits and shows that the pattern of deposition varies with time

1982-01-01

112

Device and method for measuring fluid flow in a conduit having a gradual bend  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Ortiz, Marcos German (Idaho Falls, ID); Boucher, Timothy J (Helena, MT)

1998-01-01

113

Useful life extension of steam-turbine elements by means of welding processes; Extension de la vida util de los elementos de las turbinas de vapor mediante procesos de soldadura  

Energy Technology Data Exchange (ETDEWEB)

The elements of the flow system in the steam turbines are subjected to a natural or accelerated wear during their operation. The stationary and the rotating blades are parts of the turbine that present damages, faults or materials wear, after some service periods, that can be from mechanical or metallurgical origin and prevent its continuous operation. This is also revealed in the equipment availability, reliability and performance diminution. Several cases are presented of recovery, and useful life extension of worn stationary blades (nozzle blocks and diaphragms), and rotating blades by means of welding processes executed in several fossil fuel power plants of Comision Federal de Electricidad. For each specific case, wear type or damage, the special processes based in welding processes, were developed. The blade recovery process also includes: the stress relieving, machining, special coating, quality control and tool design. Once the recovery process is completed, the components were installed back in the turbines for their utilization. The application of the welding technologies developed for blade recovery, represents just a fraction of the cost of new blades, that results in an economic saving. [Espanol] Los elementos del sistema de flujo de las turbinas de vapor sufren un desgaste natural o acelerado durante su operacion. Los alabes fijos y moviles son las partes de la turbina que despues de ciertos periodos de servicio presentan danos, fallas o desgaste del material que pueden ser de origen mecanico o metalurgico y no permiten su operacion continua. Esto se refleja tambien en la disminucion de la disponibilidad, confiabilidad y rendimiento del equipo. Se presentan varios casos de recuperacion y prolongacion de la vida util de alabes fijos (bloques de toberas y diafragmas) y moviles danados y gastados a causa de procesos de soldadura que se llevaron a cabo en varias plantas termoelectricas de la Comision Federal de Electricidad. Para cada caso especifico, tipo de desgaste o dano, se desarrollaron los procedimientos especiales basados en procesos de soldadura. El proceso de recuperacion de alabes incluye tambien: relevado de esfuerzos, maquinado, recubrimiento especial, control de calidad y diseno del herramental. Una vez terminado el proceso de recuperacion, los componentes se instalaron nuevamente en las turbinas para su servicio. La aplicacion de las tecnologias de soldadura desarrolladas para recuperar los alabes, representa una fraccion del costo de alabes nuevos, lo que resulta en un ahorro economico.

Mazur Czerwiec, Zdzislaw; Cristalinas Navarro, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1994-03-01

114

ESTUDIO DE LAS CONDICIONES DE EXTRACCIÓN POR ARRASTRE CON VAPOR DEL ACEITE ESENCIAL DE LAUREL DE CERA (Morella pubescens) STUDY OF EXTRACTION CONDITIONS OF "LAUREL DE CERA" (Morella pubescens) ESSENTIAL OIL BY MEANS OF STEAM DISTILLATION  

Directory of Open Access Journals (Sweden)

Full Text Available El laurel de cera (Morella pubescens) es un árbol que por sus características resulta muy apropiado para el control de la erosión, y cuyos frutos son utilizados por comunidades campesinas del sur de Colombia para la obtención de una cera que se emplea en el proceso de elaboración de la panela. En esta investigación se estudió el proceso de extracción del aceite esencial de las hojas del laurel de cera mediante la técnica de arrastre con vapor, y su efecto sobre la composición de los metabolitos secundarios volátiles presentes en dicho aceite. Los factores estudiados en el proceso de extracción fueron el tamaño de partícula y el tiempo de extracción, y las variables de respuesta consideradas fueron el área total del cromatograma (cuentas) como parámetro indicador de la concentración del aceite y el porcentaje relativo del componente mayoritario. Se determinó que tanto el tiempo como la interacción tiempo - tamaño de partícula tienen efectos significativos (valor de PBecause of its characteristics, the "Laurel de Cera" tree (Morella pubescens) proves to be very appropriate for the erosion control. Its fruits are employed as a means to obtain wax that is used in the process of making Panela by rural communities settled in the southern region of Colombia. The extraction process of essential oil from "Laurel de Cera" tree leaves through steam distillation and its effects over the composition of volatile secondary metabolites present were considered for the research. Particle size and extraction time were the studied factors. The chromatogram total area (counts) taken as the oil concentration indicator parameter and the relative percentage were the considered response variables. According to the previous information, it was possible to determine that the time as well as the interaction time - particle size have significant effects (P-value <0,05) over the essential oil's concentration. It was also possible to observe a meaningful increment in the chromatogram's area for the majority component when the extraction time was increased. The identification of the volatile secondary metabolites present in the essential oil was carried out through a gas chromatography/mass spectrometry (GC-MS). Such procedure gave as results trans caryophyllene (23,3%), ?-selinene (10,7%), ?-selinene (10,0%) caryophyllene oxide (4,8%), seline-3,7(11)-diene (3,3%) and ?-elemene (2,6%) as majority components. These compounds' biological activities allow thinking that the essential oil from the "Laurel de Cera" tree leaves could be of great interest for the pharmabusiness and the cosmetic industries.

OSCAR ARANGO; ANDRÉS HURTADO; PATRICIA CASTILLO; MÓNICA SANTACRUZ

2009-01-01

115

Evaluation of the ITER cable in conduit conductor heat transfer  

Energy Technology Data Exchange (ETDEWEB)

Convective heat transfer correlations in dual channel Cable In Conduit Conductor (CICC) are presented as functions of friction factor, and based on the Reynolds-Colburn analogy using the Stanton number. The developed thermohydraulic model determines helium temperatures in both channels, with the real geometrical spiral perforation. It is applied with pertinence to the Poloidal Field Full Size Joint Sample (PF-FSJS) and shows good agreement between the experimental measurements and the calculated temperatures, characterised by a 0.43 m space constant. The heat load applied in the bundle region induces density imbalance; the gravity effect in this vertical sample is evaluated and discussed. (authors)

Nicollet, S.; Ciazynski, D.; Duchateau, J.L.; Lacroix, B.; Renard, B

2004-07-01

116

Evaluation of the ITER cable in conduit conductor heat transfer  

International Nuclear Information System (INIS)

[en] Convective heat transfer correlations in dual channel Cable In Conduit Conductor (CICC) are presented as functions of friction factor, and based on the Reynolds-Colburn analogy using the Stanton number. The developed thermohydraulic model determines helium temperatures in both channels, with the real geometrical spiral perforation. It is applied with pertinence to the Poloidal Field Full Size Joint Sample (PF-FSJS) and shows good agreement between the experimental measurements and the calculated temperatures, characterised by a 0.43 m space constant. The heat load applied in the bundle region induces density imbalance; the gravity effect in this vertical sample is evaluated and discussed. (authors)

2004-01-01

117

Bare metal stenting for obstructed small diameter homograft conduits in the right ventricular outflow tract.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Our aim was to assess acute hemodynamic changes with stent insertion, outcomes, and factors associated with increased longevity of stented small diameter homograft conduits. BACKGROUND: Right ventricle-to-pulmonary artery (RV-PA) homograft conduits are commonly used to palliate RV outflow tract obstruction. Bare metal stenting (BMS) and transcatheter pulmonary valve implantation have been shown to relieve obstructed larger diameter conduits and may delay surgical conduit reintervention. Less is known about BMS of small conduits. METHODS AND RESULTS: From 1992 to 2009, BMS was performed to relieve obstruction in 106 homograft conduits that were ?12 mm at implant. The peak RV-PA gradient fell from 54.3 ± 17.4 mm Hg at baseline to 46.1 ± 15.2 mm Hg after balloon dilation alone and to 25.1 ± 11.4 mm Hg with stenting (all P < 0.001). Higher pre-BMS gradient and RV pressure were the only factors associated with higher post-BMS RV-PA gradient (?30 mm Hg; both P < 0.001). There were no procedural deaths, two patients required surgical removal of embolized stents. At a median follow-up of 1.6 years, 83 conduits were replaced; freedom from conduit reoperation after BMS was 66% ± 5% at 1 year and 28% ± 5% at 3 years. Factors associated with shorter freedom from reoperation included implanted conduit diameter <10 mm (P = 0.009), higher post-stent RV-PA gradient (P = 0.026), and higher post-stent RV pressure (P < 0.01); only post-stent RV pressure remained significant on multivariable analysis (P < 0.001). CONCLUSION: BMS was acutely effective for the treatment of obstructed small diameter homograft conduits, with low morbidity. Prolongation of small diameter homograft conduit longevity with BMS may be useful in the lifetime management of conduit dysfunction in this patient population.

Carr M; Bergersen L; Marshall AC; Keane JF; Lock JE; Emani SM; McElhinney DB

2013-01-01

118

How I choose conduits and configure grafts for my patients-rationales and practices.  

UK PubMed Central (United Kingdom)

Coronary artery bypass grafting (CABG) continues to be an effective therapy for many patients with lasting long-term durability and consistent outcomes, despite the development of percutaneous revascularization. The long-term outcome for surgical revascularization depends on multiple variables, including the choice of conduits. However, the choice of coronary conduits has been studied and debated for decades now. In this review article, we examined the current evidences and described our choice on coronary conduits and grafting strategies at our medical center.

Cheng A; Slaughter MS

2013-07-01

119

Treatment of right ventricle to pulmonary artery conduit stenosis in infants with hypoplastic left heart syndrome.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To determine the incidence of right ventricle-to-pulmonary artery (RV-PA) conduit stenosis after the Norwood I operation in patients with hypoplastic left heart syndrome (HLHS), and to determine whether the treatment strategy of RV-PA conduit stenosis has an influence on interstage and overall survival. METHODS: Ninety-six patients had a Norwood operation with RV-PA conduit between 2002 and 2011. Details of reoperations/interventions due to conduit obstruction prior to bidirectional superior cavopulmonary anastomosis (BSCPA) were collected. RESULTS: Overall pre-BSCPA mortality was 17%, early mortality after Norwood, 6%. Early angiography was performed in 34 patients due to desaturation at a median of 8 days after the Norwood operation. Fifteen patients (16%) were diagnosed with RV-PA conduit stenosis that required treatment. The location of the conduit stenosis was significantly different in the patients with non-ringed (proximal) and the patients with ring-enforced conduit (distal), P = 0.004. In 6 patients, a surgical revision of the conduit was performed; 3 of them died prior to BSCPA. Another 6 patients had a stent implantation and 3 were treated with balloon dilatation followed by a BSCPA in the subsequent 2 weeks. All patients who were treated interventionally for RV-PA conduit obstruction had a successful BSCPA. Patients who received a surgical RV-PA conduit revision had a significantly higher interstage (P = 0.044) and overall mortality (P = 0.011) than those who received a stent or balloon dilatation of the stenosis followed by an early BSCPA. CONCLUSIONS: RV-PA conduit obstruction after Norwood I procedure in patients with HLHS can be safely and effectively treated by stent implantation, balloon dilatation and early BSCPA. Surgical revision of the RV-PA conduit can be reserved for patients in whom an interventional approach fails, and an early BSCPA is not an option.

Münsterer A; Kasnar-Samprec J; Hörer J; Cleuziou J; Eicken A; Malcic I; Lange R; Schreiber C

2013-09-01

120

A polylactic acid non-woven nerve conduit for facial nerve regeneration in rats.  

UK PubMed Central (United Kingdom)

This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean?±?SD, 5051?±?2335), followed by autologous nerves (4233?±?590) and silicone tubes (1604?±?148). Axon diameter was significantly greater in the PLA tube group (5.17?±?1.69 µm) than in the silicone tube group (4.25?±?1.60 µm) and no significant difference was found between the PLA tube and autograft (5.53?±?1.93 µm) groups. Myelin thickness was greatest for the autograft group (0.65?±?0.24 µm), followed by the PLA tube (0.54?±?0.18 µm) and silicone tube (0.38?±?0.12 µm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation. Copyright © 2012 John Wiley & Sons, Ltd.

Matsumine H; Sasaki R; Yamato M; Okano T; Sakurai H

2012-06-01

 
 
 
 
121

One-year appraisal of a new aortic root conduit with sinuses of Valsalva.  

UK PubMed Central (United Kingdom)

OBJECTIVES: We evaluate the clinical results 1 year after an anatomic reconstruction of the aortic root in which we used a specifically designed aortic root prosthesis that incorporates the sinuses of Valsalva. MATERIAL AND METHODS: The new aortic Dacron prosthesis has a proximal portion in the Dacron conduit that expands on implantation, creating pseudosinuses. During a 12-month period, 28 patients (mean age 59 +/- 14 years) underwent a Bentall operation (12 cases), a remodeling procedure (7 cases), and a reimplantation procedure (9 cases) with the use of a new aortic root conduit. All patients had aortic root aneurysm with an anatomically normal (for the valve-sparing procedure) or diseased aortic valve (for the Bentall operation). Five patients had aortic dissection and 5 had Marfan disease. The mean follow-up was 6 +/- 3 months. All patients underwent postoperative transesophageal and transthoracic echocardiographic studies. RESULTS: All patients survived and were in good clinical condition at the latest follow-up. Postoperative echocardiography showed a marked reduction in ventricular volumes in all patient groups (P <.0005). In the Bentall group the new prosthesis appeared to reduce the tension on the coronary ostial sutures. In patients undergoing both types of valve-sparing procedures a similar normal anatomy of the aortic root was reconstructed. In the reimplantation group the anulus was smaller than in the remodeling group (P =.01). Patients undergoing the reimplantation procedure had less bleeding and a lower incidence of residual valve insufficiency. CONCLUSIONS: The new aortic root prosthesis allowed the reconstruction of the aortic root anatomy in all types of surgical techniques with low postoperative morbidity.

De Paulis R; De Matteis GM; Nardi P; Scaffa R; Colella DF; Bassano C; Tomai F; Chiariello L

2002-01-01

122

System and method for bidirectional flow and controlling fluid flow in a conduit  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.

Ortiz, Marcos German (Idaho Falls, ID)

1999-01-01

123

Chronic dissection and aneurysmal dilatation of a BioValsalva conduit.  

Science.gov (United States)

The BioValsalva (Vascutek Terumo, Renfrewshire, Scotland, UK) conduit is the first commercially available prefabricated bioprosthetic aortic valved conduit. We present a case of chronic dissection of a BioValsalva valved conduit presenting as a 7.5-cm aortic root aneurysm 1 year after a Bentall operation. Intraoperatively, the conduit was found to have dissected from the annulus upward, and the coronary buttons were avulsed from the inner layers while remaining attached to the outer layer. Both the outer layer and the coronary buttons were grossly dilatated. PMID:23816079

Yigzaw, Yikuno A; Lau, Kelvin K W; Baig, Kamran; Uppal, Rakesh

2013-07-01

124

Chronic dissection and aneurysmal dilatation of a BioValsalva conduit.  

UK PubMed Central (United Kingdom)

The BioValsalva (Vascutek Terumo, Renfrewshire, Scotland, UK) conduit is the first commercially available prefabricated bioprosthetic aortic valved conduit. We present a case of chronic dissection of a BioValsalva valved conduit presenting as a 7.5-cm aortic root aneurysm 1 year after a Bentall operation. Intraoperatively, the conduit was found to have dissected from the annulus upward, and the coronary buttons were avulsed from the inner layers while remaining attached to the outer layer. Both the outer layer and the coronary buttons were grossly dilatated.

Yigzaw YA; Lau KK; Baig K; Uppal R

2013-07-01

125

Catalytic Reactor For Oxidizing Mercury Vapor  

Energy Technology Data Exchange (ETDEWEB)

A catalytic reactor (10) for oxidizing elemental mercury contained in flue gas is provided. The catalyst reactor (10) comprises within a flue gas conduit a perforated corona discharge plate (30a, b) having a plurality of through openings (33) and a plurality of projecting corona discharge electrodes (31); a perforated electrode plate (40a, b, c) having a plurality of through openings (43) axially aligned with the through openings (33) of the perforated corona discharge plate (30a, b) displaced from and opposing the tips of the corona discharge electrodes (31); and a catalyst member (60a, b, c, d) overlaying that face of the perforated electrode plate (40a, b, c) opposing the tips of the corona discharge electrodes (31). A uniformly distributed corona discharge plasma (1000) is intermittently generated between the plurality of corona discharge electrode tips (31) and the catalyst member (60a, b, c, d) when a stream of flue gas is passed through the conduit. During those periods when corona discharge (1000) is not being generated, the catalyst molecules of the catalyst member (60a, b, c, d) adsorb mercury vapor contained in the passing flue gas. During those periods when corona discharge (1000) is being generated, ions and active radicals contained in the generated corona discharge plasma (1000) desorb the mercury from the catalyst molecules of the catalyst member (60a, b, c, d), oxidizing the mercury in virtually simultaneous manner. The desorption process regenerates and activates the catalyst member molecules.

Helfritch, Dennis J. (Baltimore, MD)

1998-07-28

126

Hydraulic and geological factors influencing conduit flow depth  

Directory of Open Access Journals (Sweden)

Full Text Available There has much been speculation as to whether cave formation should occur at, above, or below the water table, but a satisfactory explanation has been lacking until recently. The last 50 years has seen extensive mapping of caves both above and, more recently, below the water table. It is now becoming apparent that there are systematic differences in depth of flow between different areas and that conduit flow to depths >100m below the water table is not uncommon. Such deep flow is facilitated by the lower viscosity of geothermally heated water at depth. Analysis of data from caves shows that depth of flow is primarily a function of flow path length, stratal dip and fracture anisotropy. This explains why conduits form at shallow depths in platform settings such as in Kentucky, at moderate depths (10–100m) in folded strata such as in England and in the Appalachian Mountains, and at depths of several hundred metres in exceptional settings where there are very long flow paths.

Worthington,S.R.H.

2005-01-01

127

Calibrated vapor generator source  

Energy Technology Data Exchange (ETDEWEB)

A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

Davies, John P. (Idaho Falls, ID); Larson, Ronald A. (Idaho Falls, ID); Goodrich, Lorenzo D. (Shelley, ID); Hall, Harold J. (Idaho Falls, ID); Stoddard, Billy D. (Idaho Falls, ID); Davis, Sean G. (Idaho Falls, ID); Kaser, Timothy G. (Idaho Falls, ID); Conrad, Frank J. (Albuquerque, NM)

1995-01-01

128

Modified conduit preparation creates a pseudosinus in an aortic valve-sparing procedure for aneurysm of the ascending aorta.  

UK PubMed Central (United Kingdom)

Mechanical valved conduit replacement of the aortic root is a durable and appropriate procedure for many diseases of the ascending aorta, but may sacrifice an anatomically salvageable aortic valve. For young active patients and for patients with "systemic" arterial disease (atherosclerosis, Marfan's syndrome) who may require future operations, life-long anticoagulation with its attendant thromboembolic versus hemorrhagic risks is not ideal. Several techniques have been suggested as aortic valve-sparing options. Recently, a procedure was described that combines the freehand homograft techniques with the standard Bentall techniques (David procedure). This innovative technique replaces the ascending aorta with a Dacron cylinder, spares the aortic valve, and restores competence and thus offers an excellent alternative. The durability of this procedure that places the aortic valve inside a cylindrical conduit without sinuses of Valsalva is unknown. In selected patients, we have used this technique to spare the aortic valve. On the basis of experimental data and preliminary computer modeling, with the hope of improving the durability, we have modified the conduit to create a "pseudosinus" in our most recent nine patients. We have done the David procedure in 10 patients. The pseudosinus modification was done in the most recent nine patients. Patients' ages ranged from 37 to 71 years (mean 49.9 years). There were five female and five male patients. Five patients had Marfan's syndrome and five patients had annuloaortic ectasia. There has been no mortality and all patients have had both early and late follow-up echocardiography. Five patients have zero to trace aortic insufficiency, four patients have trace to mild aortic insufficiency, and one patient has mild or "1+" aortic insufficiency. Aortic insufficiency has not progressed in any patient during the 18 months of follow-up. The patient with 1+ aortic insufficiency has no activity limits, good ventricular function, and no evidence of congestive symptoms. One patient who had extensive thoracoabdominal aneurysmal disease has undergone subsequent replacement of the descending aorta to the level of the renal arteries and has done well. Aortic valve-sparing replacement of the aortic root is an excellent procedure for any patient with an ascending aortic aneurysm and an anatomically salvageable valve. We believe that by modifying the proximal conduit and creating a "pseudosinus" into which the leaflets can retract without contact of the cylindrical conduit we may increase the longevity of the native aortic valve in this procedure.

Cochran RP; Kunzelman KS; Eddy AC; Hofer BO; Verrier ED

1995-06-01

129

Chemical vapor infiltration using microwave energy  

Energy Technology Data Exchange (ETDEWEB)

This invention is comprised of a method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

Devlin, D.J.; Currier, R.P.; Laia, J.R.; Barbero, R.S.

1992-12-31

130

Chemical vapor infiltration using microwave energy  

Energy Technology Data Exchange (ETDEWEB)

A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process. 5 figures.

Devlin, D.J.; Currier, R.P.; Laia, J.R. Jr.; Barbero, R.S.

1993-10-19

131

Chemical vapor infiltration using microwave energy  

Energy Technology Data Exchange (ETDEWEB)

A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

Devlin, David J. (Los Alamos, NM); Currier, Robert P. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Barbero, Robert S. (Santa Cruz, NM)

1993-01-01

132

The separation of hydrocarbons from waste vapor streams  

International Nuclear Information System (INIS)

Hydrocarbon vapors generated from industrial processes dispersed into air are contributing factors for the creation of photochemical smog. The separation of hydrocarbon vapor by means of membranes is in case of some applications a technically simple and economic process. A membrane vapor separation process with a following treatment of the retentate by catalytic incineration is introduced in this paper.

1989-01-01

133

Does a skeletonized or pedicled right gastro-epiploic artery improve patency when used as a conduit in coronary artery bypass graft surgery?  

UK PubMed Central (United Kingdom)

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether skeletonization of the right gastro-epiploic artery (RGEA) improves graft patency in coronary artery bypass grafting (CABG). Altogether >25 papers were found using the reported search, of which 11 papers represented the best evidence to answer this clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes and results are tabulated. Four out of the 11 papers were comparative studies (skeletonized conduits vs. pedicled conduits) and four studies produced one-year follow-up data. No studies revealed long-term patency rates as there was no follow-up data beyond five years. It is important to note that the evidence in the literature is based in a Japanese population. The vast majority of the target vessel which had been grafted by the RGEA was the right coronary artery and more specifically the posterior descending artery (PDA). The association between off-pump technique, sequential grafting, skeletonization of the RGEA with the harmonic scalpel and angiographic patency has not been adequately assessed. The studies reveal excellent patency rates for both early and mid-term skeletonized RGEA conduits. Overall patency rates were 97.7% within three months, 92.4% at a mean of approximately 1 year, 91.5% at a mean of approximately 2 years, and 86.4% at 4 years. In the four comparative studies, skeletonization patency was at least comparable and in one study superior to pedicled conduits. One study revealed a higher four-year cumulative patency rate for skeletonized conduits in comparison to a previous study by the same author where pedicled grafts were used. In conclusion, patency rates exceeded 95% in 10 studies for a follow-up of up to three months postoperatively. The evidence which supports the use of a 'skeletonized' RGEA is growing and this paper demonstrates clearly that in terms of patency, a skeletonized RGEA to the PDA should be considered as a conduit for CABG surgery especially when total arterial revascularization strategy with in situ conduits and no manipulation of the ascending aorta is the treatment of choice.

Ali E; Saso S; Ashrafian H; Athanasiou T

2010-02-01

134

Does a skeletonized or pedicled right gastro-epiploic artery improve patency when used as a conduit in coronary artery bypass graft surgery?  

Science.gov (United States)

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether skeletonization of the right gastro-epiploic artery (RGEA) improves graft patency in coronary artery bypass grafting (CABG). Altogether >25 papers were found using the reported search, of which 11 papers represented the best evidence to answer this clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes and results are tabulated. Four out of the 11 papers were comparative studies (skeletonized conduits vs. pedicled conduits) and four studies produced one-year follow-up data. No studies revealed long-term patency rates as there was no follow-up data beyond five years. It is important to note that the evidence in the literature is based in a Japanese population. The vast majority of the target vessel which had been grafted by the RGEA was the right coronary artery and more specifically the posterior descending artery (PDA). The association between off-pump technique, sequential grafting, skeletonization of the RGEA with the harmonic scalpel and angiographic patency has not been adequately assessed. The studies reveal excellent patency rates for both early and mid-term skeletonized RGEA conduits. Overall patency rates were 97.7% within three months, 92.4% at a mean of approximately 1 year, 91.5% at a mean of approximately 2 years, and 86.4% at 4 years. In the four comparative studies, skeletonization patency was at least comparable and in one study superior to pedicled conduits. One study revealed a higher four-year cumulative patency rate for skeletonized conduits in comparison to a previous study by the same author where pedicled grafts were used. In conclusion, patency rates exceeded 95% in 10 studies for a follow-up of up to three months postoperatively. The evidence which supports the use of a 'skeletonized' RGEA is growing and this paper demonstrates clearly that in terms of patency, a skeletonized RGEA to the PDA should be considered as a conduit for CABG surgery especially when total arterial revascularization strategy with in situ conduits and no manipulation of the ascending aorta is the treatment of choice. PMID:19903686

Ali, Erden; Saso, Srdjan; Ashrafian, Hutan; Athanasiou, Thanos

2009-11-10

135

Retubularization of the ileocystoplasty patch for conversion into an ileal conduit.  

UK PubMed Central (United Kingdom)

INTRODUCTION: We present the outcomes and long-term follow-up of patients who underwent conversion to an ileal conduit urinary diversion using the retubularized patch from the initial augmentation ileocystoplasty. METHODS: We reviewed the charts of all patients who underwent this surgery at our centre. The indications for surgery, workup, clinical outcomes and complication rates were assessed. Patient-reported symptom response based on global response assessment (GRA) was determined and used as a subjective measure of overall treatment effectiveness. RESULTS: Thirteen patients with either bladder pain syndrome/interstitial cystitis (BPS/IC) (n = 11) or neurogenic bladder (n = 2) were followed for a mean of 80 months. The most common indication for surgical conversion was persistent lower urinary tract symptoms (LUTS) or bladder pain. Late complications were frequent, typically low-grade, and usually manageable with conservative therapy; the most common were urinary tract infections (n = 6) and parastomal hernias (n = 5). Two patients developed ureteric strictures. Nine of 13 patients required additional surgery to manage complications or persistent symptoms. Only 5 of 11 GRA respondents reported a successful therapeutic outcome and BPS/IC patients who underwent concurrent cystourethrectomy tended to be most satisfied (2/3). Nevertheless, several patients still achieved symptom control when no other treatment options were available to them. CONCLUSION: Conversion to an ileal conduit using the retubularized ileocystoplasty patch offers several technical and therapeutic advantages over creating a urinary diversion from a new bowel segment. It should therefore be considered a viable treatment option in patients who have exhausted more conservative management of their LUTS.

Massaro PA; Gajewski JB; Bailly G

2013-07-01

136

Application of HfC coatings to carbon/carbon composite bodies by means of chemical vapor deposition. Aufbringung von HfC-Schichten auf Kohlenstoff/Kohlenstoff-Verbundkoerpern durch chemische Gasphasenabscheidung  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project was to develop a high-temperature oxidation protection for carbon/carbon composites (C/C) and capillary siliconized C/C (C/SiC) by chemical vapor deposition of hafnium carbide. It was already at the beginning of the research project that adherent, mechanically stable coatings and protective coatings compatible with a variety of substrates were produced. (MM)

Emig, G.; Schoch, G.; Kern, F.; Wormer, O.G.

1994-01-01

137

Bail out use of the Gore Excluder following pulmonary conduit rupture during transcatheter pulmonary valve replacement.  

UK PubMed Central (United Kingdom)

This report describes the use of the Gore Excluder self-expanding stent to successfully exclude a contained right ventricle to pulmonary artery conduit rupture during transcatheter pulmonary valve replacement (tPVR). This stent was designed for percutaneous abdominal aortic aneurysm exclusion; however, its use in this setting allowed progression to tPVR following conduit rupture without the need for emergent surgery.

Sosnowski CR; Kenny D; Hijazi ZM

2013-02-01

138

Successful implantation of Thoratec assist device: wrapping of outflow conduit in Hemashield graft.  

Science.gov (United States)

Persistent oozing and bleeding through the wall of the built-in outflow conduit in mechanical circulatory assist devices is a troublesome problem. Wrapping the outflow conduit of Thoratec in a Hemashield graft without preclotting completely prevents oozing and bleeding. PMID:9307498

Minami, K; Arusoglu, L; Koyanagi, T; el-Banayosy, A; Körner, M M; Körfer, R

1997-09-01

139

Recent advances in artificial nerve conduit design: strategies for the delivery of luminal fillers.  

UK PubMed Central (United Kingdom)

Artificial nerve conduits offer an attractive alternative to nerve autografts for the repair of peripheral nerve injuries and several commercially-available conduits are currently on the market. However, at present, utilization of these conduits is limited to the repair of nerve gaps less than 3 cm in length. Thus, current research is focused on how best to design artificial conduits with improved nerve regeneration potential over longer distances. Successful nerve regeneration necessitates that the cells, extracellular matrix components, and growth factors involved interact in a highly specific manner that is tightly coordinated. Combinatorial approaches that take into account these interactions and conduits that utilize supportive factors, such as neurotrophins and stem cells, may be key components of the next generation of artificial conduits. Additionally, design strategies that combine physical cues for contact guidance and biochemical signals to enhance cellular function have shown promise. This review highlights recent advances in artificial nerve conduit design, focusing on the use of luminal fillers, with special focus on the various techniques for accessory cell and/or growth factor delivery into artificial nerve conduits.

Pabari A; Yang SY; Mosahebi A; Seifalian AM

2011-11-01

140

Replacement of a stented biologic prosthesis within an aortic valved conduit.  

UK PubMed Central (United Kingdom)

A 68-year-old man was referred for severe aortic regurgitation 10 years after aortic root replacement with a valved conduit containing a stented bioprosthesis that had been sutured inside of the vascular tube graft, rather than at its extremity. Because of this simple modification of the Bentall concept, replacing the prosthetic valve within the aortic conduit was easy and uneventful.

Gatti G; Moncada A; Minati A; Pappalardo A

2012-03-01

 
 
 
 
141

Replacement of a stented biologic prosthesis within an aortic valved conduit.  

Science.gov (United States)

A 68-year-old man was referred for severe aortic regurgitation 10 years after aortic root replacement with a valved conduit containing a stented bioprosthesis that had been sutured inside of the vascular tube graft, rather than at its extremity. Because of this simple modification of the Bentall concept, replacing the prosthetic valve within the aortic conduit was easy and uneventful. PMID:22365015

Gatti, Giuseppe; Moncada, Alessandro; Minati, Alessandro; Pappalardo, Aniello

2012-03-01

142

Hybrid conducting polymer-hydrogel conduits for axonal growth and neural tissue engineering.  

UK PubMed Central (United Kingdom)

Successfully and efficiently bridging peripheral nerve gaps without the use of autografts is a substantial clinical advance for peripheral nerve reconstructions. Novel templating methods for the fabrication of conductive hydrogel guidance channels for axonal regeneration are designed and developed. PEDOT is electrodeposited inside the lumen to create fully coated-PEDOT agarose conduits and partially coated-PEDOT agarose conduits.

Abidian MR; Daneshvar ED; Egeland BM; Kipke DR; Cederna PS; Urbanchek MG

2012-11-01

143

A new nerve guide conduit material composed of a biodegradable poly(phosphoester).  

Science.gov (United States)

There is a resurgence of interest in the development of degradable and biocompatible polymers for fabrication of nerve guide conduits (NGCs) in recent years. Poly(phosphoester) (PPE) polymers are among the attractive candidates in this context, in view of their high biocompatibility, adjustable biodegradability, flexibility in coupling fragile biomolecules under physiological conditions and a wide variety of physicochemical properties. The feasibility of using a biodegradable PPE, P(BHET-EOP/TC), as a novel NGC material was investigated. Two types of conduits were fabricated by using two batches of P(BHET-EOP/TC) with different weight-average molecular weights (Mw) and polydispersity indexes (PI). The polymers as well as conduits were non-toxic to all six types of cells tested, including primary neurones and neuronally differentiated PC12 cells. After in situ implantation in the sciatic nerve of the rat, two types of conduits triggered a similar tissue response, inducing the formation of a thin tissue capsule composed of approximately eight layers of fibroblasts surrounding the conduits at 3 months. Biological performances of the conduits were examined in the rat sciatic nerve model with a 10 mm gap. Although tube fragmentation, even tube breakage, was observed within less than 5 days post-implantation, successful regeneration through the gap occurred in both types of conduits, with four out of 10 in the Type I conduits (Mw 14,900 and PI 2.57) and 11 out of 12 in the Type II conduits (Mw 18,900 and PI 1.72). The degradation of conduits was further evidenced by increased roughness on the tube surface in vivo under scanning electron microscope and a mass decrease in a time-dependent manner in vitro. The Mw of the polymers dropped 33 and 24% in the Type I and II conduits, respectively, in vitro within 3 months. Among their advantages over other biodegradable NGCs, the PPE conduits showed negligible swelling and no crystallisation after implantation. Thus, these PPE conduits can be effective aids for nerve regeneration with potential to be further developed into more sophisticated NGCs that have better control of the conduit micro-environment for improved nerve regeneration. PMID:11352095

Wang, S; Wan, A C; Xu, X; Gao, S; Mao, H Q; Leong, K W; Yu, H

2001-05-01

144

A new nerve guide conduit material composed of a biodegradable poly(phosphoester).  

UK PubMed Central (United Kingdom)

There is a resurgence of interest in the development of degradable and biocompatible polymers for fabrication of nerve guide conduits (NGCs) in recent years. Poly(phosphoester) (PPE) polymers are among the attractive candidates in this context, in view of their high biocompatibility, adjustable biodegradability, flexibility in coupling fragile biomolecules under physiological conditions and a wide variety of physicochemical properties. The feasibility of using a biodegradable PPE, P(BHET-EOP/TC), as a novel NGC material was investigated. Two types of conduits were fabricated by using two batches of P(BHET-EOP/TC) with different weight-average molecular weights (Mw) and polydispersity indexes (PI). The polymers as well as conduits were non-toxic to all six types of cells tested, including primary neurones and neuronally differentiated PC12 cells. After in situ implantation in the sciatic nerve of the rat, two types of conduits triggered a similar tissue response, inducing the formation of a thin tissue capsule composed of approximately eight layers of fibroblasts surrounding the conduits at 3 months. Biological performances of the conduits were examined in the rat sciatic nerve model with a 10 mm gap. Although tube fragmentation, even tube breakage, was observed within less than 5 days post-implantation, successful regeneration through the gap occurred in both types of conduits, with four out of 10 in the Type I conduits (Mw 14,900 and PI 2.57) and 11 out of 12 in the Type II conduits (Mw 18,900 and PI 1.72). The degradation of conduits was further evidenced by increased roughness on the tube surface in vivo under scanning electron microscope and a mass decrease in a time-dependent manner in vitro. The Mw of the polymers dropped 33 and 24% in the Type I and II conduits, respectively, in vitro within 3 months. Among their advantages over other biodegradable NGCs, the PPE conduits showed negligible swelling and no crystallisation after implantation. Thus, these PPE conduits can be effective aids for nerve regeneration with potential to be further developed into more sophisticated NGCs that have better control of the conduit micro-environment for improved nerve regeneration.

Wang S; Wan AC; Xu X; Gao S; Mao HQ; Leong KW; Yu H

2001-05-01

145

In vitro evaluation of right ventricular outflow tract reconstruction with bicuspid valved polytetrafluoroethylene conduit.  

Science.gov (United States)

Conduits available for right ventricular outflow tract (RVOT) reconstruction eventually become stenotic and/or insufficient due to calcification. In order to reduce the incidence of reoperations we have developed and used a bicuspid valved polytetrafluoroethylene (PTFE) conduit for the RVOT reconstruction. The purpose of this study is to investigate the hemodynamic performance of the new design using a pediatric in vitro right heart mock loop. PTFE conduit has been used for the complete biventricular repair of 20 patients (age 1.7±6 years) with cyanotic congenital defects. To account for the large variability of conduit sizes, 14, 16, 22, and 24-mm conduit sizes were evaluated using an in vitro flow loop comprised of a pulsatile pump with cardiac output (CO) of 1.2-3.2L/min, bicuspid valved RVOT conduit, pulmonary artery, venous compartments, and the flow visualization setup. We recorded the diastolic valve leakage and pre- and post-conduit pressures in static and pulsatile settings. In vitro valve function and overall hemodynamic performance was evaluated using high-speed cameras and ultrasonic flow probes. Three-dimensional flow fields for different in vivo conduit curvatures and inflow regimes were calculated by computational fluid dynamics (CFD) analysis to further aid the conduit design process. The average pressure drop over the valved conduits was 0.8±1.7mm Hg for the CO range tested. Typical values for regurgitant fraction, peak-to-peak pressure gradient, and effective office area were 23±2.1%, 13±2.4mm Hg, and 1.56±0.2 cm(2) , respectively. High-speed videos captured the intact valve motion with asymmetrical valve opening during the systole. CFD simulations demonstrated the flow skewness toward the major curvature of the conduit based on the pulmonic curvature. In vitro evaluation of the bicuspid valved PTFE conduit coincides well with acceptable early clinical performance (mild insufficiency), with relatively low pressure drop, and intact valve motion independent from the conduit curvature, orientation or valve location, but at the expense of increased diastolic flow regurgitation. These findings benchmark the baseline performance of the bicuspid valved conduit and will be used for future designs to improve valve competency. PMID:21092044

Dur, Onur; Yoshida, Masahiro; Manor, Philip; Mayfield, Alice; Wearden, Peter D; Morell, Victor O; Pekkan, Kerem

2010-11-01

146

In vitro evaluation of right ventricular outflow tract reconstruction with bicuspid valved polytetrafluoroethylene conduit.  

UK PubMed Central (United Kingdom)

Conduits available for right ventricular outflow tract (RVOT) reconstruction eventually become stenotic and/or insufficient due to calcification. In order to reduce the incidence of reoperations we have developed and used a bicuspid valved polytetrafluoroethylene (PTFE) conduit for the RVOT reconstruction. The purpose of this study is to investigate the hemodynamic performance of the new design using a pediatric in vitro right heart mock loop. PTFE conduit has been used for the complete biventricular repair of 20 patients (age 1.7±6 years) with cyanotic congenital defects. To account for the large variability of conduit sizes, 14, 16, 22, and 24-mm conduit sizes were evaluated using an in vitro flow loop comprised of a pulsatile pump with cardiac output (CO) of 1.2-3.2L/min, bicuspid valved RVOT conduit, pulmonary artery, venous compartments, and the flow visualization setup. We recorded the diastolic valve leakage and pre- and post-conduit pressures in static and pulsatile settings. In vitro valve function and overall hemodynamic performance was evaluated using high-speed cameras and ultrasonic flow probes. Three-dimensional flow fields for different in vivo conduit curvatures and inflow regimes were calculated by computational fluid dynamics (CFD) analysis to further aid the conduit design process. The average pressure drop over the valved conduits was 0.8±1.7mm Hg for the CO range tested. Typical values for regurgitant fraction, peak-to-peak pressure gradient, and effective office area were 23±2.1%, 13±2.4mm Hg, and 1.56±0.2 cm(2) , respectively. High-speed videos captured the intact valve motion with asymmetrical valve opening during the systole. CFD simulations demonstrated the flow skewness toward the major curvature of the conduit based on the pulmonic curvature. In vitro evaluation of the bicuspid valved PTFE conduit coincides well with acceptable early clinical performance (mild insufficiency), with relatively low pressure drop, and intact valve motion independent from the conduit curvature, orientation or valve location, but at the expense of increased diastolic flow regurgitation. These findings benchmark the baseline performance of the bicuspid valved conduit and will be used for future designs to improve valve competency.

Dur O; Yoshida M; Manor P; Mayfield A; Wearden PD; Morell VO; Pekkan K

2010-11-01

147

Ground water flux distribution between matrix, fractures, and conduits: constraints on modeling  

Directory of Open Access Journals (Sweden)

Full Text Available Calculations are presented to show the relative contribution of the matrix, fracture, and conduit permeability to the overall flow of ground water through a karst aquifer. The conceptual model is a cross-section spanning the full width and thickness of the aquifer. A constant, but adjustable head is assumed. The rock matrix is characterized by an adjustable hydraulic conductivity. Varying proportions of fractures and conduits of adjustable fracture apertures and conduit diameters were the calculational parameters. Calculations used Darcy’s law for matrix flow, the cube law for fracture flow, and the Darcy-Weisbach equation for conduit flow. The results show a surprising dominance of fracture flow in the early stages of aquifer development. A focusing mechanism is needed to localize the flow into a relatively small number of conduits.

White,W.B.; White,E.L.

2005-01-01

148

Effect of the conduit material on CICC performance under high cycling loads  

Energy Technology Data Exchange (ETDEWEB)

Recent ITER Model Coils and CRPP tests on Nb3Sn Cable in Conduit Conductors (CICC) showed a significant and unexpected increase in the broadness of the transition to the normal state, resulting in degradation of superconducting properties. To investigate these phenomena two CICC samples were built with identical 144 strand cables but different conduit materials. One sample had titanium conduit with low coefficient of thermal expansion (CTE), the other had stainless steel conduit. The purpose of this experiment was to study changes in strand properties in the cable (n-value, I{sub c}, T{sub cs}), the effect of cycling and high electromagnetic load and the effect of the conduit on the CICC performance.

Martovetsky, N N; Bruzzone, P; Stepanov, B; Wesche, R; Gung, C; Minervini, J V; Takayasu, M; Goodrich, L F; Ekin, J W; Nijhuis, A

2004-09-01

149

Palliative urinary conduit diversion in cases of intolerable urinary discomfort  

Energy Technology Data Exchange (ETDEWEB)

Fifteen patients with incurable gynecological cancers, all primary radiation treated and all having severe urinary discomfort due to urinary tract injuries were retrospectively examined after urinary conduit diversion. All have been followed-up until termination or until all survivors had lived for 6 months after the operation. Twelve of the 15 were discharged from the hospital, 10 of whom survived the first 6 months. Of those discharged 82% of the cumulated sum of postoperative observations days was spent out of the hospital. At the end of the observation period nine patients had been supplied with a colostomy as well, thus having double stomas. All six patients still alive declared in retrospect that given the choice again, they would still be willing to undergo the operation.

Lyndrup, J.; Sorensen, B.L.

1983-12-01

150

Effect of SR manipulation on conduit artery dilation in humans.  

UK PubMed Central (United Kingdom)

The impact of manipulating shear stress on conduit artery vasodilation has not been comprehensively described in vivo. We hypothesized that manipulation of SR through the brachial and radial arteries would be associated with corresponding changes in diameter. We performed a series of studies involving the following: (1) leg cycle exercise at increasing intensities (?70 and 85% maximum heart rate [HRmax]) with simultaneous bilateral measurement of SR in the radial arteries; (2) leg cycle exercise for 30 minutes at 80% HRmax with simultaneous bilateral measurement of velocity and diameter in the brachial arteries; and (3) bilateral forearm heating for 30 minutes with simultaneous bilateral measurement of brachial artery diameter and blood velocity. Cycling and forearm heating interventions were performed in the presence of unilateral cuff inflation throughout the experiment, or starting during the intervention (15 minutes), to manipulate SR responses. Cuff placement was associated with lower radial artery SR responses (cuffed versus uncuffed, 248±49 versus 349±105 L/s 85% HRmax; P<0.01), and diameter responses were similarly attenuated (2.45±0.30 versus 2.78±0.20 mm 85% HRmax; P<0.05). Exercise performed at 80% HRmax in the presence of unilateral cuff inflation also reduced brachial artery SR (cuffed versus uncuffed; 258±107 versus 454±157 L/s; P<0.01) and diameter (3.96±0.39 versus 4.20±0.45 mm). Finally, cuff inflation decreased the impact of forearm heating on brachial SR (cuffed versus uncuffed; 262±97 versus 440±106 L/s; P<0.01) and diameter (4.35±0.54 versus 4.87±0.47 mm; P<0.05). Similar significant differences between the cuffed and uncuffed limbs in SR and diameter were observed when cuff inflation occurred during exercise or heating. Our findings strongly implicate SR as an important stimulus to increase conduit artery diameter in humans.

Carter HH; Dawson EA; Birk GK; Spence AL; Naylor LH; Cable NT; Thijssen DH; Green DJ

2013-01-01

151

Vapor spill pipe monitor  

Energy Technology Data Exchange (ETDEWEB)

The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

Bianchini, G.M.; McRae, T.G.

1983-06-23

152

MR jet velocity mapping for assessment of conduit and valve stenosis and aortic coarctation  

International Nuclear Information System (INIS)

This paper assesses short echo time MR jet velocity mapping as a means of measuring poststenotic jet velocities in vitro and in patients. MR jet velocity mapping was performed with a Picker 0.5-T machine and the field even-echo rephasing sequence with a 3.6-msec echo time, in stenotic flow phantoms and in 49 patients (mean age, 31 years; range, 12-72 years) with stenoses of valved conduits (n = 22), native heart valves (n = 123), and aortic coarctation (n = 15). Where possible, results were compared with those available from Doppler US and catheter studies. MR velocity maps clearly demonstrated the shape and location of jets, and velocity measurements correlated well with Doppler measurements up to 6 m/sec in vitro (r = .996). In patients, jet velocities up to 5.5 m/sec were mapped, and for 21 cases in which comparison was possible, agreement with Doppler was good (means of peak velocity measurements, 2.7 m/sec; standard deviation of differences, 0.2 m/sec). Unclear velocity maps were attributed to slight misplacement of the image plane in seven cases.

1990-01-01

153

Explosives Vapor Characterization.  

Science.gov (United States)

The vaporous emissions from seventeen explosives were investigated by gas chromatographic and combined gas chromatographic/mass spectrometric techniques using a novel collection device. The vapor emission rates were followed as a function of time untile t...

F. H. Jarke S. M. Gordon

1982-01-01

154

Procedure for obtaining a urine sample from a urostomy, ileal conduit, and colon conduit: a best practice guideline for clinicians.  

UK PubMed Central (United Kingdom)

The purpose of this document was to define the correct technique for obtaining a urine sample from a urostomy, ileal, or colon conduit. While healthcare providers do not commonly encounter patients with a urostomy, knowledge of the correct procedure to obtain a urine specimen is essential. Urine samples obtained incorrectly from a urostomy can lead to inaccurate cultures, resulting in an improper diagnosis and treatment, which can endanger the life of a patient. This column presents patient preparation, the procedure to obtain a specimen with and without a catheter, and aftercare of the patient and specimen. This best practice guideline has been developed by a panel of certified ostomy nurses serving on the Wound, Ostomy and Continence Nurses (WOCN) Society's Clinical Practice Ostomy Committee. The guideline has undergone content validation through a consensus-building process by the WOCN Society, which was managed by the Center for Clinical Investigation.

Mahoney M; Baxter K; Burgess J; Bauer C; Downey C; Mantel J; Perkins J; Rice M; Salvadalena G; Schafer V; Sheppard S

2013-05-01

155

Engineering a multimodal nerve conduit for repair of injured peripheral nerve  

Science.gov (United States)

Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate hydrogel. This indicates return of some feeling to the limb via the fully-configured conduit. Immunohistochemical analysis of the implanted conduits removed from the rats after the four-week implantation period confirmed the presence of myelinated axons within the conduit and distal to the site of implantation, further supporting that the conduit promoted nerve repair over this period of time. This study describes the design considerations and fabrication of a novel multicomponent, multimodal bio-engineered synthetic conduit for peripheral nerve repair.

Quigley, A. F.; Bulluss, K. J.; Kyratzis, I. L. B.; Gilmore, K.; Mysore, T.; Schirmer, K. S. U.; Kennedy, E. L.; O'Shea, M.; Truong, Y. B.; Edwards, S. L.; Peeters, G.; Herwig, P.; Razal, J. M.; Campbell, T. E.; Lowes, K. N.; Higgins, M. J.; Moulton, S. E.; Murphy, M. A.; Cook, M. J.; Clark, G. M.; Wallace, G. G.; Kapsa, R. M. I.

2013-02-01

156

Engineering a multimodal nerve conduit for repair of injured peripheral nerve.  

UK PubMed Central (United Kingdom)

Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate hydrogel. This indicates return of some feeling to the limb via the fully-configured conduit. Immunohistochemical analysis of the implanted conduits removed from the rats after the four-week implantation period confirmed the presence of myelinated axons within the conduit and distal to the site of implantation, further supporting that the conduit promoted nerve repair over this period of time. This study describes the design considerations and fabrication of a novel multicomponent, multimodal bio-engineered synthetic conduit for peripheral nerve repair.

Quigley AF; Bulluss KJ; Kyratzis IL; Gilmore K; Mysore T; Schirmer KS; Kennedy EL; O'Shea M; Truong YB; Edwards SL; Peeters G; Herwig P; Razal JM; Campbell TE; Lowes KN; Higgins MJ; Moulton SE; Murphy MA; Cook MJ; Clark GM; Wallace GG; Kapsa RM

2013-02-01

157

Temperature control of a steam generator by means of an hybrid system PID-RLC; Control de las temperaturas de un generador de vapor mediante un sistema hibrido PID-RLC  

Energy Technology Data Exchange (ETDEWEB)

A description is made of the design and evaluation of an hybrid control system, formed by a quadratic gaussian linear regulator (QLR) and proportional integral derivative (PID) type regulators. This scheme is used to control the reheater and secondary superheater steam temperatures of a steam generator model with a maximum capacity of 2,150,000 pounds per hour. Once applied to the model of a 300 MW steam power plant, this system showed better results than the traditional schemes and inclusively better than some modern control schemes. This fact characterizes it as a high potential system to be applied to steam power plants. [Espanol] Se describe el diseno y la evaluacion de un sistema de control hibrido, formado por un regulador lineal cuadratico gaussiano (RLC) y reguladores tipo proporcional integral derivativo (PID). Este esquema se utiliza para controlar las temperaturas de vapor del recalentador y sobrecalentador secundario del modelo de un generador de vapor con capacidad maxima de 2,150,000 libras por hora. Una vez aplicado al modelo de una unidad termoelectrica de 300 MW, este sistema produjo mejores resultados que los esquemas tradicionales e incluso mejores que algunos esquemas de control moderno. Esto lo caracteriza como un sistema con un alto potencial para aplicarse a unidades termoelectricas.

Palomares Gonzalez, Daniel; Garcia Mendoza, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1990-12-31

158

Influence of conduit network geometry on solute transport in karst aquifers with a permeable matrix  

Science.gov (United States)

In karst aquifers with significant matrix permeability, water and solutes are exchanged between the conduits and carbonate matrix. Transport through the matrix increases the spread of solutes and increases travel times. This study numerically evaluates advective solute transport in synthetic karst systems that contain 3D branching conduit networks. Particle tracking is performed to analyze the spatial and temporal transport history of solute that arrives at the conduit outlet. Three measures of transport connectivity are used to quantify the solute migration behavior: the skewness of the particle arrival time distribution, the normalized fifth percentile of arrival times, and the fraction of the total travel time that occurs within conduits. All three of these metrics capture the influence of conduit network geometry on solute transport. A more tortuous network leads to enhanced conduit-matrix mixing, which reduces the transport connectivity and yields a broader distribution of solute arrival times. These results demonstrate that the conduit network geometry is an important control on solute transport in karst systems with a permeable matrix.

Ronayne, Michael J.

2013-06-01

159

Degradation properties of the electrostatic assembly PDLLA/CS/CHS nerve conduit  

Energy Technology Data Exchange (ETDEWEB)

A poly(d,l-lactic acid)/chondroitin sulfate/chitosan (PDLLA/CS/CHS) nerve conduit for repairing nerve defects was prepared by electrostatic assembly and the thermally induced phase separation technique. The hydrophilic characteristics of the PDLLA/CS/CHS assembly nerve conduits were improved markedly. The degradation behavior of the nerve conduit with various assembly layers was evaluated by a pH change, weight loss rate and molecular weight change. The pH of the solution of the nerve conduit could be effectively adjusted by varying the layer numbers and overcoming the acidity-caused auto-acceleration of PDLLA; the nerve conduit can retain its integrity in a phosphate buffer solution after being degraded for 3 months. After such a conduit was implanted in the rat for 3 months, obvious degradation occurred, but the regenerated nerve was integrated and it grew successfully from the proximal to distal nerve stump. All these results implied that the degradation rate of the prepared conduit can adapt to the regeneration of the peripheral nerve, which might be a new derivative of PDLLA-based biodegradable materials for repairing nerve injuries without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as shown by PDLLA.

Xu Haixing [School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070 (China); Yan Yuhua; Wan Tao; Li Shipu, E-mail: yanyuhua8@126.co [Biomedical Materials and Engineering Research Center, Wuhan University of Technology, Wuhan 430070 (China)

2009-08-15

160

Representation of water abstraction from a karst conduit with numerical discrete-continuum models  

Science.gov (United States)

Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most karst models assume quasi steady-state flow in conduits neglecting conduit associated drainable storage (CADS). The concept of CADS considers storage volumes, where karst water is not part of the active flow system but rather hydraulically connected to conduits (for example karstic voids and large fractures). The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g. large scale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this paper is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical hybrid model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ) boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The affect and proper functioning of these modifications is demonstrated by simplified model studies. Both enhancements, CAD storage and the FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is potentially able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems.

Reimann, T.; Giese, M.; Geyer, T.; Liedl, R.; Maréchal, J. C.; Shoemaker, W. B.

2013-04-01

 
 
 
 
161

Representation of water abstraction from a karst conduit with numerical discrete-continuum models  

Directory of Open Access Journals (Sweden)

Full Text Available Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most karst models assume quasi steady-state flow in conduits neglecting conduit associated drainable storage (CADS). The concept of CADS considers storage volumes, where karst water is not part of the active flow system but rather hydraulically connected to conduits (for example karstic voids and large fractures). The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g. large scale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this paper is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical hybrid model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ) boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The affect and proper functioning of these modifications is demonstrated by simplified model studies. Both enhancements, CAD storage and the FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is potentially able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems.

T. Reimann; M. Giese; T. Geyer; R. Liedl; J. C. Maréchal; W. B. Shoemaker

2013-01-01

162

Diversity Of Clast Types And Their Implications For Conduit Processes  

Science.gov (United States)

Small volume, sub-plinian andesite eruptions produce a range of clasts which can be either texturally diverse but compositionally similar or vice versa. Each clast type records the particular mechanism by which it was generated and can involve either purely geochemical or physical processes or interacting physico-chemical mechanisms. To understand the genesis of clast types we investigated the texture, mineral and bulk chemical composition, as well as melt inclusion studies, from clasts in deposits of the last sub-plinian eruption of Mt. Taranaki, New Zealand. These results are used, along with data obtained from studies of other lava dome- forming eruptions, to explore processes in the shallow crustal magma storage region and the changes the magma experiences once it leaves that region. Further, shallow, intra-edifice conduit processes are identified that explain the diversity in clast types. Five basic rock types were produced during the AD 1655 Burrell Lapilli eruption of Mt. Taranaki: dense grey andesite clasts with a range in bulk composition from 57.1 to 59.5 wt. % SiO2, and four pumice types grey, brown, black and grey-brown banded clasts which are similar in bulk composition to the andesite clasts with SiO2 between 55.5-56.0 wt. %. However, the pumice types are fundamentally different in terms of vesicularity and somewhat different glass chemistry. Bulk vesicularities are highest for brown pumice with a median of 70.7 %, followed by grey pumice with 68.5 %, banded pumice with 63.8 %, and then black pumice with 49.9 %. Moreover, the permeability of the Burrell Lapilli samples is generally up to 10 times higher at given porosities (e.g. 5.3x10-11m2 at bulk vesicularity of 75.1 %) compared to literature data for dacitic and rhyolitic pumice compositions. The development of different coloured pumice types is the result of slightly differing physical magma properties (e.g. temperature, viscosity, volatile content) resulting in changes in vesicle texture and glass composition. This is directly controlled by syn-eruptive decompression and fragmentation processes rather than pre-eruptive magma evolution. These processes occur within an stratified upper conduit (including lateral variations in magma properties) and explain the generation of different pumice types and is consistent with field observations of a succession of three pyroclastic flows deposits of grey, brown and grey pumice. These three units represent eruption pulses and correspond to three levels of bubble nucleation at different growth rates. The brown pumice formation represents slower volatile exsolution and bubble growth with subsequent microlite crystallisation. This pre- mature bubble network caused slower fragmentation rates, and hence, pulsation during fragmentation.

Platz, T.; Cronin, S. J.; Cashman, K. V.; Stewart, R. B.

2006-12-01

163

Investigation of co-sorption of gases and vapors as a means to enhance indoor air quality. Phase 2. Air dehumidification and removal of indoor pollutants by liquid desiccants. Topical report, April 1990-July 1992  

Energy Technology Data Exchange (ETDEWEB)

Several solid and liquid desiccants were studied to determine their ability for removing pollutants from indoor air in the presence of water vapor. This volume presents the study on dehumidification of air in a packed bed absorber by aqueous solutions of lithium chloride and triethylene glycol and their pollutant removal capabilities. A packed bed absorber-stripper system has been designed and tested successfully for dehumidification of air and pollutant removal. Measured flooding conditions corresponded closely with existing empirical correlations. For a given height of packing, the column efficiency increased as either the air flow rate decreased or the liquid flow rate increased. The mass transfer coefficients increased with increasing air and liquid flow rates. Lowering the liquid temperature improved the column performance significantly.

Hines, A.L.; Ghosh, T.K.

1993-02-01

164

Regional myocardial dysfunction following Norwood with right ventricle to pulmonary artery conduit in patients with hypoplastic left heart syndrome.  

UK PubMed Central (United Kingdom)

BACKGROUND: Improved early survival has led many centers to use the right ventricle-to-pulmonary artery (RVPA) conduit instead of the modified Blalock-Taussig shunt for Norwood palliation of hypoplastic left-heart syndrome. However, there is concern regarding the potential deleterious effects of the required right ventriculotomy for placement of the RVPA conduit on global and regional right ventricular (RV) function. The purpose of this study was to investigate global and regional RV wall motion abnormalities after Norwood palliation with RVPA conduit using Velocity Vector Imaging (VVI). METHODS: Thirty consecutive patients with hypoplastic left-heart syndrome who underwent stage 2 palliation between January 2007 and December 2009 were identified from the surgical database. VVI was performed on two-dimensional echocardiographic images obtained before second-stage palliation. Peak systolic circumferential and radial velocity, strain, and strain rate were measured from parasternal short-axis and apical four-chamber views. RV ejection fraction was measured using the biplane modified Simpson's rule. Regional RV systolic deformations were compared between different RV segments. VVI measures were also compared with RV systolic function. In a subgroup (n = 14), VVI was repeated on follow-up after stage 2 palliation to evaluate changes in regional and global RV deformation. RESULTS: A total of 30 patients (20 males) were studied. The median age at the time of interstage echocardiography was 12 weeks (range, 8-18 weeks). In the short axis, average peak systolic circumferential strain values for the anterior, posterior, septal, and RV free wall segments were 3.79 ± 2.52%, 11.4 ± 5.2%, 13.3 ± 6.5%, and 11.1 ± 5.0%, respectively. From the short-axis view, the anterior RV segment (ventriculotomy site) exhibited significantly reduced circumferential velocity, peak systolic strain, and strain rate (P < .0001). Mean global VVI measurements were correlated with RV ejection fraction. On follow-up after stage 2 palliation, the ventriculotomy region showed persistently reduced velocity, peak systolic strain, and strain rate compared with all other segments. CONCLUSIONS: In patients with hypoplastic left-heart syndrome after Norwood palliation with RVPA conduit, RV myocardial deformation was significantly reduced at the ventriculotomy site, which persisted after stage 2 palliation. VVI-derived measures demonstrating impairment of global systolic myocardial deformation were correlated with RV systolic function. Long-term multicenter studies to evaluate the effects of ventriculotomy scar on single systemic right ventricle are required.

Menon SC; Minich LL; Casper TC; Puchalski MD; Hawkins JA; Tani LY

2011-08-01

165

Metal vapor laser including hot electrodes and integral wick  

Energy Technology Data Exchange (ETDEWEB)

A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube.

Ault, Earl R. (Livermore, CA); Alger, Terry W. (Tracy, CA)

1995-01-01

166

Engineering of a synthetic electron conduit in living cells  

Science.gov (United States)

Engineering efficient, directional electronic communication between living and nonliving systems has the potential to combine the unique characteristics of both materials for advanced biotechnological applications. However, the cell membrane is designed by nature to be an insulator, restricting the flow of charged species; therefore, introducing a biocompatible pathway for transferring electrons across the membrane without disrupting the cell is a significant challenge. Here we describe a genetic strategy to move intracellular electrons to an inorganic extracellular acceptor along a molecularly defined route. To do so, we reconstitute a portion of the extracellular electron transfer chain of Shewanella oneidensis MR-1 into the model microbe Escherichia coli. This engineered E. coli can reduce metal ions and solid metal oxides ?8× and ?4× faster than its parental strain. We also find that metal oxide reduction is more efficient when the extracellular electron acceptor has nanoscale dimensions. This work demonstrates that a genetic cassette can create a conduit for electronic communication from living cells to inorganic materials, and it highlights the importance of matching the size scale of the protein donors to inorganic acceptors.

Jensen, Heather M.; Albers, Aaron E.; Malley, Konstantin R.; Londer, Yuri Y.; Cohen, Bruce E.; Helms, Brett A.; Weigele, Peter; Groves, Jay T.; Ajo-Franklin, Caroline M.

2010-01-01

167

A Cable-in-Conduit Superconductor for Pulsed Accelerator Magnets  

CERN Document Server

Superconducting magnets for future accelerators such as the SIS-100 ring of the International Accelerator Facility at GSI-Darmstadt, or a superconducting injector at the LHC, require that the magnetic field is pulsed with high repetition rate and high reliability over periods of several years. As an example the SIS-100 at the IAF is planned to be operated up to 2 T at 4 T/s for more than 100 millions cycles. Achieving these objectives requires that the superconductor has an excellent mechanical stability as well as a sufficient energy margin to tolerate foreseen and unforeseen energy inputs. In addition the cryogenic loss must be controlled at low levels, while the field errors due to coupling currents must be compatible with the beam dynamics requirements. In this paper we describe a cable-in-conduit design that is suitable for the challenging operating conditions described above, we give the expected performances and report on the on-going manufacturing demonstration and planned supporting tests.

Bottura, L; Fischer, E; Kauschke, M; Moritz, G; Vysotsky, V S; Sytnikov, V E; Wilson, M

2005-01-01

168

Limitations of nerve repair of segmental defects using acellular conduits.  

Science.gov (United States)

The authors present the case of a 20-year-old man who, 3 months after his initial injury, underwent repair of a 1.7-cm defect of the ulnar nerve at the wrist; repair was performed with an acellular nerve allograft. Given the absence of clinical or electrophysiological recovery at 8 months postrepair, the patient underwent reexploration, excision of the "regenerated cable," and rerepair of the ulnar nerve with sural nerve autografts. Histology of the cable demonstrated minimal axonal regeneration at the midpoint of the repair. At the 6- and 12-month follow-ups of the sural nerve graft repair, clinical and electrophysiological evidence of both sensory and motor reinnervation of the ulnar nerve and associated hand muscles was demonstrated. In this report, the authors describe a single case of failed acellular nerve allograft and correlate the results with basic science and human studies reporting length and diameter limitations in human nerve repair utilizing grafts or conduits devoid of viable Schwann cells. PMID:23746100

Berrocal, Yerko A; Almeida, Vania W; Levi, Allan D

2013-06-07

169

A conduit dilation model of methane venting from lake sediments  

Science.gov (United States)

Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

Scandella, Benjamin P.; Varadharajan, Charuleka; Hemond, Harold F.; Ruppel, Carolyn; Juanes, Ruben

2011-03-01

170

Relaxation of microparticles exposed to hydrodynamic forces in microfluidic conduits.  

UK PubMed Central (United Kingdom)

The behavior of microparticles exposed to gravitational and lift forces and to the velocity gradient in flow velocity profile formed in microfluidic conduits is studied from the viewpoint of the transient period (the relaxation) between the moment at which a particle starts to be transported by the hydrodynamic flow and the time at which it reaches an equilibrium position, characterized by a balance of all active forces. The theoretical model allowing the calculation of the relaxation time is proposed. The numerical calculus based on the proposed model is compared with the experimental data obtained under different experimental conditions, namely, for different lengths of microfluidic channels, different average linear velocities of the carrier liquid, and different sizes and densities of the particles used in the study. The results are important for the optimization of microfluidic separation units such as microthermal field-flow fractionation channels in which the separation or manipulation of the microparticles of various origin, synthetic, natural, biological, etc., is performed under similar experimental conditions but by applying an additional thermodynamic force.

Jan?a J; Halabalová V; Polášek V; Vašina M; Menshikova AY

2011-02-01

171

Nerve conduit scaffolds for discrete delivery of two neurotrophic factors.  

UK PubMed Central (United Kingdom)

Axonal repair and regeneration remain critical due to lack of appropriate delivery systems for efficient release of neurotrophic factors (NTFs). Recently, we have demonstrated the synergistic activity of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) on axonal regeneration. Combined delivery of GDNF and NGF with individually controlled release kinetics may be crucial for exploiting their synergistic action on axonal elongation in animals. For engineering discrete NTF release kinetics, we have developed several nerve conduits (NCs) using collagen (Col) and silk fibroin (SF); the NC were made of Col or SF alone, or of Col and SF layers, or of Col/SF blends, all loaded with GDNF and NGF. All NC types provided sustained combined release of NGF and GDNF over 28days. NC made of combinations of Col and SF showed reduced burst and more sustained dual release of GDNF and NGF. SF/Col-based NC scaffolds provide an adaptable delivery system for growth factors and hold potential for nerve regeneration and possibly for other tissue engineering applications.

Catrina S; Gander B; Madduri S

2013-09-01

172

Granulomatous conduit for intrathecal infusion of morphine and bupivacaine.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Intrathecal drug delivery systems (IT-DDSs) have gained more widespread use in patients with non-cancer-related pain, notably failed back surgery syndrome and spinal arachnoiditis. Secondary to the longer life spans of these patients, more complications have been discovered with IT-DDSs. With an estimated incidence of 1% to 3%, an uncommon but serious complication is that of granuloma formation. CASE REPORT: We describe a case of a 38-year-old woman with a malfunctioning IT-DDS containing morphine and bupivacaine. The device had stopped providing relief for several months because of presumed leakage from the connection site between the pump and the proximal catheter. The IT-DDS spontaneously resumed functioning. The IT-DDS was explanted for low battery life, upon which we discovered that the leakage site had been encapsulated by drug concretion and granuloma formation, thus providing a sealed conduit that reestablished drug flow between the pump and the catheter. CONCLUSIONS: This case report reinforces the view that the infusate is the causal agent of this lesion.

Webb DM; Schneider JR; Lober RM; Vender JR

2011-03-01

173

Injunctions against mere conduit of information protected by copyright  

DEFF Research Database (Denmark)

This paper includes an in-depth analysis of EU law and Scandinavian law on injunctions against internet access providers (IAPs) performing as mere conduit of information protected by copyright. In recent Scandinavian case law, courts have granted preliminary injunctions which have caused IAPs to either shut down specific internet connections allegedly used to infringe copyright or to block access to internet content, which allegedly infringed applicable copyright rules. This paper considers some significant legal challenges, which are emerging in the wake of this case law, and which should attract attention in all European member states. Firstly, it is shown that rules on preliminary injunctions are generally unable to safeguard the significant legitimate interests of third parties, which may be harmed by such relief, and that a proper implementation of Art. 8(3) of the Infosoc Directive requires rules, which take into due consideration the special aspects related to enforcement of copyright on the internet through IAPs. Secondly, it is shown that the termination of internet connections and the blocking of access to internet content may not support the public policies behind copyright law and also may restrict the freedom of expression under European human rights law. The analysis is based on a brief account for the relevant EU Directives, the implementation of these Directives in the Scandinavian countries and the Scandinavian case law regarding use of injunctions against IAPs to enforce copyright on the internet.

Sandfeld Jakobsen, SØren; Petersen, Clement Salung

2011-01-01

174

Structure of a Bacterial Cell Surface Decaheme Electron Conduit  

Energy Technology Data Exchange (ETDEWEB)

Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves deca-heme cytochromes that are located on the bacterial cell surface at the termini of trans-outermembrane (OM) electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or participating in extracellular inter-cytochrome electron exchange along ‘nanowire’ appendages. We present a 3.2 Å crystal structure of one of these deca-heme cytochromes, MtrF, that allows the spatial organization of the ten hemes to be visualized for the first time. The hemes are organized across four domains in a unique crossed conformation, in which a staggered 65 Å octa-heme chain transects the length of the protein and is bisected by a planar 45 Å tetra-heme chain that connects two extended Greek key split ?-barrel domains. The structure provides molecular insight into how reduction of insoluble substrate (e.g. minerals), soluble substrates (e.g. flavins) and cytochrome redox partners might be possible in tandem at different termini of a trifurcated electron transport chain on the cell surface.

Clarke, Thomas A.; Edwards, Marcus; Gates, Andrew J.; Hall, Andrea; White, Gaye; Bradley, Justin; Reardon, Catherine L.; Shi, Liang; Beliaev, Alex S.; Marshall, Matthew J.; Wang, Zheming; Watmough, Nicholas; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.

2011-05-23

175

Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Directional drilling at Unzen Volcano in Japan duringmid of 2004 penetrated the magma conduit and successfullyrecovered samples of the lava dike that is believed to havefed the 1991–1995 eruption. The dike was sampled about1.3 km below the volcano’s summit vent and is intrudedinto a broader conduit zone that is 0.5 km wide. This zoneconsists of multiple older lava dikes and pyroclastic veinsand has cooled to less than 200?C. The lava dike sample wasunexpectedly altered, suggesting that circulation of hydrothermalfluids rapidly cools the conduit region of even veryactive volcanoes. It is likely that seismic signals monitoredprior to emergence of the lava dome reflected fracturing ofthe country rocks, caused by veining as volatiles escapedpredominantly upward, not outward, from the rising magma.Geophysical and geological investigation of cuttings andcore samples from the conduit and of bore-hole logging datacontinues.

Setsuya Nakada; Kozo Uto

2005-01-01

176

Local recurrence of bladder cancer after cystectomy with orthotopic bladder substitution and ileal conduit  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To present the local recurrence rates after radical cystectomy for advanced bladder cancer and to compare them between patients with orthotopic neobladder and ileal conduit. Patients and methods: 97 patients with radical cystectomy were analyzed: 75 patients with orthotopic ileal neobladder, operated from 1985. to 2006, and 22 patients with ileal conduit, operated from 2000. to 2006. Results: Overall recurrence rate was 41.3% in the neobladder group, and 50% in the ileal conduit group. The rate of pelvic, upper urinary tract and urethral recurrence was 13.3%, 8%, and 10.6% in the neobladder group, and 9.1%, 13.6% and 9.1% in the ileal conduit group. Conclusion: Comparable recurrence rates, operative time, the complexity of the surgical technique and the results between two groups, strongly support the construction of orthotopic neobladder, as superior in functional, esthetic, and psychological point of view.

Pej?i? T.; Hadži-?oki? J.; A?imovi? M.; Markovi? B.B.; Maksimovi? H.M.; Milkovi? B.; Kajmakovi? B.

2007-01-01

177

Device for mooring and connecting a submarine conduit, and method employing the said device  

Energy Technology Data Exchange (ETDEWEB)

An assembly for mooring a submarine conduit to a pipeline or a fixed structure such as a storage tank is described. The assembly comprises a mooring head, a fixed mooring frame and a movable mooring arm. The mooring head is fixed to the end of the conduit to be connected. The mooring arm is mounted on the fixed mooring frame and is effective to receive the mooring head. The mooring arm is displaceable in a horizontal plane on the mooring frame. An end of the pipeline to which the conduit is to be connected is located on the rotational axis of the mooring arm. A junction pipe connects the end of the conduit to the end of the fixed pipeline. A cable attached to the mooring head passes through the mooring arm and is attached to a winch on the surface for drawing the mooring head into engagement with the mooring arm.

Patinet, J.

1981-03-10

178

The effect of asphalt resinous substances on the intensity of paraffin overgrowth of oil conduits  

Energy Technology Data Exchange (ETDEWEB)

The effect of asphalt resinous substances on the periodicity of cleaning oil conduits is shown. A classification table is cited whose use makes it possible to evaluate the periodicity of throughput of cleaning devices based on their content.

Gallyamov, A.K.; Mastobayev, B.N.; Yukin, A.F.

1983-01-01

179

Total correction in tetralogy of Fallot with anomalous major coronary artery: an alternative method to conduit use.  

UK PubMed Central (United Kingdom)

INTRODUCTION: A coronary artery anomaly precludes the use of a trans-annular patch in right ventricular outflow tract (RVOT) reconstruction. Herein we present three patients with coronary artery anomalies who underwent total corrective operations without using a conduit. METHODS: Between 2007 and 2010, 84 patients with tetralogy of Fallot (TOF) were operated on. Nine (9.4%) of them had a coronary artery anomaly. Three (3.1%) of the patients were operated on using the double-outflow technique and two had a Blalock-Taussig shunt before the total corrective operation. In two patients, the left anterior descending artery (LAD) and in one, the right coronary artery (RCA) crossed the RVOT. RESULTS: Postoperatively, the right-to-left ventricular pressure ratios were 0.45, 0.59 and 0.60 after cardiopulmonary bypass. No gradient was detected in the RVOT in postoperative echocardiographical measurements (< 15 mmHg gradient). In all three patients, there were moderate pulmonary insufficiencies. All were discharged home on the sixth day postoperatively. Mean follow-up duration was 9.8 ± 8 months. In the follow up of all three patients, there were moderate pulmonary insufficienciencies but no right ventricular dysfunction. CONCLUSION: The 'double-outflow' technique is appropriate for TOF patients with a major coronary artery anomaly since it can easily be performed without the need of a conduit.

Saritas B; Ozker E; Vuran E; Yoruker U; Ayabakan C; Turkoz R

2012-03-01

180

Fontan operation for patients with complex anatomy: the intra-atrial conduit technique.  

UK PubMed Central (United Kingdom)

The extracardiac conduit type of total cavopulmonary connection (TCPC) is the most common variation of the modified Fontan operation in current use. For patients with some forms of complex anatomy (eg, dextrocardia in situs solitus or asplenia syndrome), we have adopted a different technique: interposition of an intra-atrial conduit between the inferior vena cava (IVC) and the superior vena cava-right pulmonary artery (SVC-RPA) connection. We report our experience with six patients.

Iacona GM; Giamberti A; Abella RF; Muñoz JA; Mendieta SG; Pomé G; Frigiola A

2012-04-01

 
 
 
 
181

Fontan operation for patients with complex anatomy: the intra-atrial conduit technique.  

Science.gov (United States)

The extracardiac conduit type of total cavopulmonary connection (TCPC) is the most common variation of the modified Fontan operation in current use. For patients with some forms of complex anatomy (eg, dextrocardia in situs solitus or asplenia syndrome), we have adopted a different technique: interposition of an intra-atrial conduit between the inferior vena cava (IVC) and the superior vena cava-right pulmonary artery (SVC-RPA) connection. We report our experience with six patients. PMID:23804784

Iacona, Gabriele M; Giamberti, Alessandro; Abella, Raul F; Muñoz, Julio Agredo; Mendieta, Saul Garcia; Pomé, Giuseppe; Frigiola, Alessandro

2012-04-01

182

The Contegra valved bovine conduit: a biomaterial for the surgical treatment of congenital heart defects.  

UK PubMed Central (United Kingdom)

Contegra, a bovine jugular vein graft, has been widely used as a preferable biomaterial in the surgical treatment of congenital heart defects, especially as a conduit for the right ventricular outflow tract reconstruction. This article aims to make a comprehensive review on the clinical outcomes of Contegra. Reports of Contegra published since 2002 were comprehensively retrieved, collected and analyzed. There were 1718 Contegra, applied in 1705 patients. The sizes of the conduits were 8-22 mm. The patients aged from newborn to 74.5 years, prevailed by pediatrics. The primary diagnosis was congenital heart defects in all cases, with Tetralogy of Fallot, truncus arteriosus and pulmonary atresia being the first three diagnoses, representing 25.6%, 16.7%, and 13.1%, respectively. Contegra was used as a tube graft in the pulmonary position in 1635 (95.9%) patients, as a monocuspid patch in 12 (0.7%), as a graft in the position of the pulmonary valve or a monocusps in 40 (2.3%), and as an inferior vena cava-pulmonary artery conduit in the Fontan procedure in 18 (1.1%) patients, respectively. Conduit reimplantation was performed in 141 (8.3%) patients 33.8 ± 37 (8.6-106.8) months after the initial conduit insertion. Conduit plasty was necessary in 6 (0.4%), and reintervention in 83 (4.9%) patients. Indications for conduit reimplantation included severe stenosis of the distal anastomosis, pseudoaneurysm of the proximal anastomosis and severe conduit regurgitation. As for the good performance, availability and longevity, Contegra is a biomaterial suitable for the right ventricular outflow tract reconstruction and for patch repair for ventricular septal defect, but not apt for Fontan procedure.

Yuan SM

2012-12-01

183

The Contegra valved bovine conduit: a biomaterial for the surgical treatment of congenital heart defects.  

Science.gov (United States)

Contegra, a bovine jugular vein graft, has been widely used as a preferable biomaterial in the surgical treatment of congenital heart defects, especially as a conduit for the right ventricular outflow tract reconstruction. This article aims to make a comprehensive review on the clinical outcomes of Contegra. Reports of Contegra published since 2002 were comprehensively retrieved, collected and analyzed. There were 1718 Contegra, applied in 1705 patients. The sizes of the conduits were 8-22 mm. The patients aged from newborn to 74.5 years, prevailed by pediatrics. The primary diagnosis was congenital heart defects in all cases, with Tetralogy of Fallot, truncus arteriosus and pulmonary atresia being the first three diagnoses, representing 25.6%, 16.7%, and 13.1%, respectively. Contegra was used as a tube graft in the pulmonary position in 1635 (95.9%) patients, as a monocuspid patch in 12 (0.7%), as a graft in the position of the pulmonary valve or a monocusps in 40 (2.3%), and as an inferior vena cava-pulmonary artery conduit in the Fontan procedure in 18 (1.1%) patients, respectively. Conduit reimplantation was performed in 141 (8.3%) patients 33.8 ± 37 (8.6-106.8) months after the initial conduit insertion. Conduit plasty was necessary in 6 (0.4%), and reintervention in 83 (4.9%) patients. Indications for conduit reimplantation included severe stenosis of the distal anastomosis, pseudoaneurysm of the proximal anastomosis and severe conduit regurgitation. As for the good performance, availability and longevity, Contegra is a biomaterial suitable for the right ventricular outflow tract reconstruction and for patch repair for ventricular septal defect, but not apt for Fontan procedure. PMID:23152287

Yuan, Shi-Min

2012-11-16

184

What influences the acidity in the gastric conduit in patients who underwent cervical esophagogastrostomy for cancer?  

UK PubMed Central (United Kingdom)

The aim of this study was to determine the factors influencing acidity in the gastric conduit after esophagectomy for cancer. Acidity and bile reflux in the stomach and in the gastric conduit were examined by 24-h pH monitoring and bilimetry in 40 patients who underwent transthoracic subtotal esophagectomy followed by esophageal reconstruction using a gastric conduit, which was pulled up to the neck through a posterior mediastinal route in 17 patients, through a retrosternal route in 10 patients, and through a subcutaneous route in 13 patients. They were examined at 1 week before surgery, at 1 month after surgery, and at 1 year after surgery. Helicobacter pylori infection was examined pathologically and using the (13) C-urea breath test. The factors influencing acidity of the gastric conduit were analyzed using the stepwise regression model. Gastric acidity assessed by percentage (%) time of pH < 4 was reduced after surgery and was significantly less in patients with H. pylori infection compared with those without H. pylori infection throughout the period from 1 week before surgery to 1 year after surgery. Duodenogastric reflux (DGR) assessed by % time absorbance > 0.14 into the lower portion of the gastric conduit was significantly increased after surgery throughout the period from 1 month after surgery to 1 year after surgery. Multivariate analysis showed that the acidity in the gastric conduit was influenced by H. pylori infection and DGR at 1 month after surgery, and by H. pylori infection and the route for esophageal reconstruction at 1 year after surgery. Acidity in the gastric conduit was significantly decreased after surgery. Acidity in the gastric conduit for esophageal substitutes is influenced by H. pylori infection and surgery. DGR influences the gastric acidity in the short-term after surgery, but not in the long-term after surgery.

Tsubuku T; Fujita H; Tanaka T; Matono S; Nishimura K; Murata K; Sueyoshi S; Shirouzu K; Aoyama Y; Yanagawa T

2011-11-01

185

What influences the acidity in the gastric conduit in patients who underwent cervical esophagogastrostomy for cancer?  

Science.gov (United States)

The aim of this study was to determine the factors influencing acidity in the gastric conduit after esophagectomy for cancer. Acidity and bile reflux in the stomach and in the gastric conduit were examined by 24-h pH monitoring and bilimetry in 40 patients who underwent transthoracic subtotal esophagectomy followed by esophageal reconstruction using a gastric conduit, which was pulled up to the neck through a posterior mediastinal route in 17 patients, through a retrosternal route in 10 patients, and through a subcutaneous route in 13 patients. They were examined at 1 week before surgery, at 1 month after surgery, and at 1 year after surgery. Helicobacter pylori infection was examined pathologically and using the (13) C-urea breath test. The factors influencing acidity of the gastric conduit were analyzed using the stepwise regression model. Gastric acidity assessed by percentage (%) time of pH 0.14 into the lower portion of the gastric conduit was significantly increased after surgery throughout the period from 1 month after surgery to 1 year after surgery. Multivariate analysis showed that the acidity in the gastric conduit was influenced by H. pylori infection and DGR at 1 month after surgery, and by H. pylori infection and the route for esophageal reconstruction at 1 year after surgery. Acidity in the gastric conduit was significantly decreased after surgery. Acidity in the gastric conduit for esophageal substitutes is influenced by H. pylori infection and surgery. DGR influences the gastric acidity in the short-term after surgery, but not in the long-term after surgery. PMID:21489042

Tsubuku, T; Fujita, H; Tanaka, T; Matono, S; Nishimura, K; Murata, K; Sueyoshi, S; Shirouzu, K; Aoyama, Y; Yanagawa, T

2011-04-13

186

Stacked vapor fed amtec modules  

Science.gov (United States)

The present invention pertains to a stacked AMTEC module. The invention includes a tubular member which has an interior. The member is comprised of a ion conductor that substantially conducts ions relative to electrons, preferably a beta"-alumina solid electrolyte, positioned about the interior. A porous electrode for conducting electrons and allowing sodium ions to pass therethrough, and wherein electrons and sodium ions recombine to form sodium is positioned about the beta"-alumina solid electrolyte. The electrode is operated at a temperature and a pressure that allows the recombined sodium to vaporize. Additionally, an outer current collector grid for distributing electrons throughout the porous electrode is positioned about and contacts the porous electrode. Also included in the invention is transporting means for transporting liquid sodium to the beta"-alumina solid electrolyte of the tubular member. A transition piece is positioned about the interior of the member and contacts the transporting means. The transition piece divides the member into a first cell and a second cell such that each first and second cell has a beta"-alumina solid electrolyte, a first and second porous electrode and a grid. The transition piece conducts electrons from the interior of the tubular member. There is supply means for supplying sodium to the transporting means. Preferably the supply means is a shell which surrounds the tubular member and is operated at a temperature such that the vaporized sodium condenses thereon. Returning means for returning the condensed sodium from the shell to the transporting means provides a continuous supply of liquid sodium to the transporting means. Also, there are first conducting means for conducting electric current from the transition piece which extends through the shell, and second conducting means for conducting electric current to the grid of the first cell which extends through the shell.

Sievers, Robert K. (North Huntingdon, PA)

1989-01-01

187

Impaired role of epoxyeicosatrienoic acids in the regulation of basal conduit artery diameter during essential hypertension.  

Science.gov (United States)

In young healthy subjects, epoxyeicosatrienoic acids synthesized by endothelial cytochrome P450 epoxygenases maintain basal conduit artery diameter during altered NO availability. Whether this compensatory mechanism is effective during essential hypertension is unknown. Radial artery diameter, blood flow, and mean wall shear stress were determined in 14 nontreated essential hypertensive patients and 14 normotensive control subjects during 8 minutes of brachial infusion for inhibitors of cytochrome P450 epoxygenases (fluconazole, 0.4 µmol/min) and NO synthase (N(G)-monomethyl-L-arginine, 8 µmol/min) alone and in combination. In controls, the radial artery diameter was reduced by fluconazole (-0.034 ± 0.012 mm) and N(G)-monomethyl-L-arginine (-0.037 ± 0.010 mm) and to a larger extent by their combination (-0.137 ± 0.011 mm), demonstrating a synergic effect. In contrast, the radial diameter in hypertensive patients was not affected by fluconazole (0.010 ± 0.014 mm) but was reduced by N(G)-monomethyl-L-arginine (-0.091 ± 0.008 mm) to a larger extent than in controls. In parallel, N(G)-monomethyl-L-arginine decreased local plasma nitrite to a lesser extent in hypertensive patients (-14 ± 5 nmol/L) than in controls (-50 ± 10 nmol/L). Moreover, the addition of fluconazole to N(G)-monomethyl-L-arginine did not further decrease radial diameter in patients (-0.086 ± 0.011 mm). Accordingly, fluconazole significantly decreased local epoxyeicosatrienoic acid plasma level in controls (-2.0 ± 0.6 ng/mL) but not in patients (-0.9 ± 0.4 ng/mL). Inhibitors effects on blood flow and endothelium-independent dilatation to sodium nitroprusside were similar between groups. These results show that, in contrast to normotensive subjects, epoxyeicosatrienoic acids did not contribute to the regulation of basal conduit artery diameter and did not compensate for altered NO availability to maintain this diameter in essential hypertensive patients. PMID:23090775

Bellien, Jeremy; Remy-Jouet, Isabelle; Iacob, Michele; Blot, Etienne; Mercier, Alain; Lucas, Daniele; Dreano, Yvonne; Gutierrez, Laurence; Donnadieu, Nathalie; Thuillez, Christian; Joannides, Robinson

2012-10-22

188

Impaired role of epoxyeicosatrienoic acids in the regulation of basal conduit artery diameter during essential hypertension.  

UK PubMed Central (United Kingdom)

In young healthy subjects, epoxyeicosatrienoic acids synthesized by endothelial cytochrome P450 epoxygenases maintain basal conduit artery diameter during altered NO availability. Whether this compensatory mechanism is effective during essential hypertension is unknown. Radial artery diameter, blood flow, and mean wall shear stress were determined in 14 nontreated essential hypertensive patients and 14 normotensive control subjects during 8 minutes of brachial infusion for inhibitors of cytochrome P450 epoxygenases (fluconazole, 0.4 µmol/min) and NO synthase (N(G)-monomethyl-L-arginine, 8 µmol/min) alone and in combination. In controls, the radial artery diameter was reduced by fluconazole (-0.034 ± 0.012 mm) and N(G)-monomethyl-L-arginine (-0.037 ± 0.010 mm) and to a larger extent by their combination (-0.137 ± 0.011 mm), demonstrating a synergic effect. In contrast, the radial diameter in hypertensive patients was not affected by fluconazole (0.010 ± 0.014 mm) but was reduced by N(G)-monomethyl-L-arginine (-0.091 ± 0.008 mm) to a larger extent than in controls. In parallel, N(G)-monomethyl-L-arginine decreased local plasma nitrite to a lesser extent in hypertensive patients (-14 ± 5 nmol/L) than in controls (-50 ± 10 nmol/L). Moreover, the addition of fluconazole to N(G)-monomethyl-L-arginine did not further decrease radial diameter in patients (-0.086 ± 0.011 mm). Accordingly, fluconazole significantly decreased local epoxyeicosatrienoic acid plasma level in controls (-2.0 ± 0.6 ng/mL) but not in patients (-0.9 ± 0.4 ng/mL). Inhibitors effects on blood flow and endothelium-independent dilatation to sodium nitroprusside were similar between groups. These results show that, in contrast to normotensive subjects, epoxyeicosatrienoic acids did not contribute to the regulation of basal conduit artery diameter and did not compensate for altered NO availability to maintain this diameter in essential hypertensive patients.

Bellien J; Remy-Jouet I; Iacob M; Blot E; Mercier A; Lucas D; Dreano Y; Gutierrez L; Donnadieu N; Thuillez C; Joannides R

2012-12-01

189

Long term peripheral nerve regeneration using a novel PCL nerve conduit.  

UK PubMed Central (United Kingdom)

The gold standard in surgical management of a peripheral nerve gap is currently autologous nerve grafting. This confers patient morbidity and increases surgical time therefore innovative experimental strategies towards engineering a synthetic nerve conduit are welcome. We have developed a novel synthetic conduit made of poly ?-caprolactone (PCL) that has demonstrated promising peripheral nerve regeneration in short-term studies. This material has been engineered to permit translation into clinical practice and here we demonstrate that histological outcomes in a long-term in vivo experiment are comparable with that of autologous nerve grafting. A 1cm nerve gap in a rat sciatic nerve injury model was repaired with a PCL nerve conduit or an autologous nerve graft. At 18 weeks post surgical repair, there was a similar volume of regenerating axons within the nerve autograft and PCL conduit repair groups, and similar numbers of myelinated axons in the distal stump of both groups. Furthermore, there was evidence of comparable re-innervation of end organ muscle and skin with the only significant difference the lower wet weight of the muscle from the PCL conduit nerve repair group. This study stimulates further work on the potential use of this synthetic biodegradable PCL nerve conduit in a clinical setting.

Reid AJ; de Luca AC; Faroni A; Downes S; Sun M; Terenghi G; Kingham PJ

2013-06-01

190

Comparison of a karst groundwater model with and without discrete conduit flow  

Science.gov (United States)

Karst aquifers exhibit a dual flow system characterized by interacting conduit and matrix domains. This study evaluated the coupled continuum pipe-flow framework for modeling karst groundwater flow in the Madison aquifer of western South Dakota (USA). Coupled conduit and matrix flow was simulated within a regional finite-difference model over a 10-year transient period. An existing equivalent porous medium (EPM) model was modified to include major conduit networks whose locations were constrained by dye-tracing data and environmental tracer analysis. Model calibration data included measured hydraulic heads at observation wells and estimates of discharge at four karst springs. Relative to the EPM model, the match to observation well hydraulic heads was substantially improved with the addition of conduits. The inclusion of conduit flow allowed for a simpler hydraulic conductivity distribution in the matrix continuum. Two of the high-conductivity zones in the EPM model, which were required to indirectly simulate the effects of conduits, were eliminated from the new model. This work demonstrates the utility of the coupled continuum pipe-flow method and illustrates how karst aquifer model parameterization is dependent on the physical processes that are simulated.

Saller, Stephen P.; Ronayne, Michael J.; Long, Andrew J.

2013-09-01

191

A Biosynthetic Nerve Guide Conduit Based on Silk/SWNT/Fibronectin Nanocomposite for Peripheral Nerve Regeneration  

Science.gov (United States)

As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.

Mottaghitalab, Fatemeh; Farokhi, Mehdi; Zaminy, Arash; Kokabi, Mehrdad; Soleimani, Masoud; Mirahmadi, Fereshteh

2013-01-01

192

Vapor spill monitoring method  

Energy Technology Data Exchange (ETDEWEB)

Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.

Bianchini, G. M.; McRae, T. G.

1985-08-20

193

Vapor spill monitoring method  

Science.gov (United States)

Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.

Bianchini, Gregory M. (Livermore, CA); McRae, Thomas G. (Livermore, CA)

1985-01-01

194

The Himalayas: barrier and conduit for gene flow.  

Science.gov (United States)

The Himalayan mountain range is strategically located at the crossroads of the major cultural centers in Asia, the Middle East and Europe. Although previous Y-chromosome studies indicate that the Himalayas served as a natural barrier for gene flow from the south to the Tibetan plateau, this region is believed to have played an important role as a corridor for human migrations between East and West Eurasia along the ancient Silk Road. To evaluate the effects of the Himalayan mountain range in shaping the maternal lineages of populations residing on either side of the cordillera, we analyzed mitochondrial DNA variation in 344 samples from three Nepalese collections (Newar, Kathmandu and Tamang) and a general population of Tibet. Our results revealed a predominantly East Asian-specific component in Tibet and Tamang, whereas Newar and Kathmandu are both characterized by a combination of East and South Central Asian lineages. Interestingly, Newar and Kathmandu harbor several deep-rooted Indian lineages, including M2, R5, and U2, whose coalescent times from this study (U2, >40 kya) and previous reports (M2 and R5, >50 kya) suggest that Nepal was inhabited during the initial peopling of South Central Asia. Comparisons with our previous Y-chromosome data indicate sex-biased migrations in Tamang and a founder effect and/or genetic drift in Tamang and Newar. Altogether, our results confirm that while the Himalayas acted as a geographic barrier for human movement from the Indian subcontinent to the Tibetan highland, it also served as a conduit for gene flow between Central and East Asia. PMID:23580401

Gayden, Tenzin; Perez, Annabel; Persad, Patrice J; Bukhari, Areej; Chennakrishnaiah, Shilpa; Simms, Tanya; Maloney, Trisha; Rodriguez, Kristina; Herrera, Rene J

2013-04-12

195

Current distribution in Cable-In-Conduit Conductors  

Energy Technology Data Exchange (ETDEWEB)

A numerical study of the current distribution in Cable-In-Conduit Conductors (CICC`s) experiencing linearly ramping transport currents and transverse magnetic fields was conducted for both infinitely long, periodic cables and finite length cables terminated in low resistance joints. The goal of the study was to gain insight into the phenomenon known as Ramp Rate Limitation, an as yet unexplained correspondence between maximum attainable current and the ramp time taken to reach that current in CICC superconducting magnets. A discrete geometric model of a 27 strand multiply twisted CICC was developed to effectively represent the flux linkages, mutual inductances, and resistive contact points between the strands of an experimentally tested cable. The results of the numerical study showed that for fully periodic cables, the current imbalances due to ramping magnetic fields and ramping transport currents are negligible in the range of experimentally explored operating conditions. For finite length, joint terminated cables, however, significant imbalances can exist. Unfortunately, quantitative results are limited by a lack of knowledge of the transverse resistance between strands in the joints. Nonetheless, general results are presented showing the dependency of the imbalance on cable length, ramp time, and joint resistance for both ramping transverse magnet fields and ramping transport currents. At the conclusion of the study, it is suggested that calculated current imbalances in a finite length cable could cause certain strands to prematurely ``quench`` -- become non-superconducting --thus leading to an instability for the entire cable. This numerically predicted ``current imbalance instability`` is compared to the experimentally observed Ramp Rate Limitation for the 27 strand CICC sample.

Ferri, M.A.

1994-05-01

196

Current distribution in Cable-In-Conduit Conductors  

International Nuclear Information System (INIS)

A numerical study of the current distribution in Cable-In-Conduit Conductors (CICC's) experiencing linearly ramping transport currents and transverse magnetic fields was conducted for both infinitely long, periodic cables and finite length cables terminated in low resistance joints. The goal of the study was to gain insight into the phenomenon known as Ramp Rate Limitation, an as yet unexplained correspondence between maximum attainable current and the ramp time taken to reach that current in CICC superconducting magnets. A discrete geometric model of a 27 strand multiply twisted CICC was developed to effectively represent the flux linkages, mutual inductances, and resistive contact points between the strands of an experimentally tested cable. The results of the numerical study showed that for fully periodic cables, the current imbalances due to ramping magnetic fields and ramping transport currents are negligible in the range of experimentally explored operating conditions. For finite length, joint terminated cables, however, significant imbalances can exist. Unfortunately, quantitative results are limited by a lack of knowledge of the transverse resistance between strands in the joints. Nonetheless, general results are presented showing the dependency of the imbalance on cable length, ramp time, and joint resistance for both ramping transverse magnet fields and ramping transport currents. At the conclusion of the study, it is suggested that calculated current imbalances in a finite length cable could cause certain strands to prematurely ''quench'' -- become non-superconducting --thus leading to an instability for the entire cable. This numerically predicted ''current imbalance instability'' is compared to the experimentally observed Ramp Rate Limitation for the 27 strand CICC sample.

1994-01-01

197

Pressure drop characteristic in a cable-in-conduit conductor  

International Nuclear Information System (INIS)

[en] A cable-in-conduit conductor (CICC) is the best candidate to satisfy requirement for a superconducting magnet to be employed in a fusion machine, such as a large operating current, high magnetic field, high breakdown voltage and so on. The present drop of the conductor is a key factor in design of a cryogenic pump to be used in a magnet system in the fusion machine. Also, pressure rise at a coil quench depends on the pressure drop characteristic of the conductor. Several workers investigated the pressure drop characteristic of CICCs. Katheder attempted to derive general correlation of the pressure drop characteristic basis on the correlation used for pebble beds. He compared his correlation with the measurements for the eight different CICCs. However, there is a large error of 75% in the maximum. It seems general formula of the pressure drop characteristic of CICC has not been provided. The authors investigate the pressure drop characteristic of 30 kA, 80 m cooling path length CICCs, whose dimension is almost same as the conductor to be employed in the fusion machine. The result indicates correlation between the Reynolds number and the friction factor of CICCs obeys the conventional formula for a smooth tube, Hagen-Poesuilli formula, in laminar flow region but does not agree with the conventional formula for a smooth tube, Blasius formula, in turbulent flow region. The experimental result is compared with Katheder's correlation. Katheder's correlation does not show good agreement with the experimental result in the turbulent flow region. The correlation that the friction factor is inversely proportional to 0.157 power of the Reynolds number and the proportional constant is 0.257 coincides better with the experimental result in this region. (author)

1995-01-01

198

Early results of valve-sparing reimplantation procedure using the Valsalva conduit: a multicenter study.  

UK PubMed Central (United Kingdom)

BACKGROUND: This study evaluates the midterm clinical results of valve-preserving aortic root reconstruction by means of a modified conduit incorporating sinuses of Valsalva. METHODS: During a 5-year period, 151 patients with aneurysm of the aortic root underwent a reimplantation type of valve-sparing procedure using the Gelweave Valsalva prosthesis that incorporates sinuses of Valsalva. There were 121 males (80.1%), and the mean age was 56.4 +/- 14.4 years (range, 14 to 83). Fourteen percent of the patients had Marfan syndrome and 8.6% had bicuspid aortic valve. Seven patients (4.6%) suffered from acute aortic dissection. Aortic replacement was extended to the arch in 14 patients (9.3%). Sixteen patients (10.6%) had associated cusp repair. RESULTS: In-hospital mortality was 3.3%, and it was significantly higher among patients operated on for acute dissection (p = 0.001) and in symptomatic patients (III-IV New York Heart Association class; p = 0.021). Follow-up (mean, 18 months; range, 1 to 60) was 100% complete. There were 2 late deaths. Ten patients (6.8%) had 3 to 4+ aortic regurgitation, and 8 of these required late aortic valve replacement. Cusp repair was associated with a high incidence of late aortic valve replacement (p = 0.005). At 5 years, freedom from aortic valve replacement and freedom from grade 3 to 4 aortic insufficiency was 90.8% +/- 3.3% and 88.7% +/- 3.6%, respectively. CONCLUSIONS: The reimplantation valve-sparing procedure with the Gelweave Valsalva prosthesis provides satisfactory results for patients with aortic root aneurysm. Aortic cusp repair may lead to late aortic insufficiency. Proper leaflet evaluation is of paramount importance in preventing residual valve regurgitation.

Pacini D; Settepani F; De Paulis R; Loforte A; Nardella S; Ornaghi D; Gallotti R; Chiariello L; Di Bartolomeo R

2006-09-01

199

Use new PLGL-RGD-NGF nerve conduits for promoting peripheral nerve regeneration  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Nerve conduits provide a promising strategy for peripheral nerve injury repair. However, the efficiency of nerve conduits to enhance nerve regeneration and functional recovery is often inferior to that of autografts. Nerve conduits require additional factors such as cell adhesion molecules and neurotrophic factors to provide a more conducive microenvironment for nerve regeneration. Methods In the present study, poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PLGL) was modified by grafting Gly-Arg-Gly-Asp-Gly (RGD peptide) and nerve growth factor (NGF) for fabricating new PLGL-RGD-NGF nerve conduits to promote nerve regeneration and functional recovery. PLGL-RGD-NGF nerve conduits were tested in the rat sciatic nerve transection model. Rat sciatic nerves were cut off to form a 10 mm defect and repaired with the nerve conduits. All of the 32 Wistar rats were randomly divided into 4 groups: group PLGL-RGD-NGF, group PLGL-RGD, group PLGL and group autograft. At 3 months after surgery, the regenerated rat sciatic nerve was evaluated by footprint analysis, electrophysiology, and histologic assessment. Experimental data were processed using the statistical software SPSS 10.0. Results The sciatic function index value of groups PLGL-RGD-NGF and autograft was significantly higher than those of groups PLGL-RGD and PLGL. The nerve conduction velocities of groups PLGL-RGD-NGF and autograft were significantly faster than those of groups PLGL-RGD and PLGL. The regenerated nerves of groups PLGL-RGD-NGF and autograft were more mature than those of groups PLGL-RGD and PLGL. There was no significant difference between groups PLGL-RGD-NGF and autograft. Conclusions PLGL-RGD-NGF nerve conduits are more effective in regenerating nerves than both PLGL-RGD nerve conduits and PLGL nerve conduits. The effect is as good as that of an autograft. This work established the platform for further development of the use of PLGL-RGD-NGF nerve conduits for clinical nerve repair.

Yan Qiongjiao; Yin Yixia; Li Binbin

2012-01-01

200

Size of the right ventricle-to-pulmonary artery conduit impacts mid-term outcome after the Norwood procedure in patients weighing less than 3 kg.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The optimal shunt size for patients who have the Norwood operation with a right ventricle-to-pulmonary artery conduit is controversial. The goal of this study is to compare outcomes of 2 shunt sizes in this population. METHODS: Between 2002 and 2010, 75 consecutive patients diagnosed with hypoplastic left heart syndrome and its variants underwent the Norwood procedure with a right ventricle-to-pulmonary artery conduit. The outcomes of 20 neonates weighing <3 kg were analyzed. RESULTS: The cumulative 30-day stage 1 survival [corrected] was 97% (95% confidence interval, 88%-99%) for all patients (73/75), 20 of whom weighed <3 kg. Nine patients had a 6-mm (group 1) and 11 patients had a 5-mm (group 2) right ventricle-to-pulmonary artery conduit. Thirty-day stage 1 survival was 88% (8/9) in group 1 and 90% (10/11) in group 2 (P = .88). The central pulmonary artery confluence size at prebidirectional cavopulmonary shunt catheterization was 4.5 ± 1.2 mm in group 1 and 2.5 ± 1.0 mm in group 2 (P = .009). The mean transpulmonary gradient was higher in group 2 (7.8 ± 3.1 mm Hg vs 4.2 ± 1.9 mm Hg; P = .036). The incidence of pulmonary artery intervention was 16% (1/7) in group 1 and 75% (6/8) in group 2 (P = .030). Survival rate at 6 months was 66% (6/9) in group 1 and 70% (7/10) in group 2 (P = .89). CONCLUSIONS: Use of a 6-mm right ventricle-to-pulmonary artery conduit showed better central pulmonary artery growth and less need for pulmonary artery intervention in the authors' experience.

Watanabe N; Anagnostopoulos PV; Shinkawa T; Johnson N; Azakie A

2012-11-01

 
 
 
 
201

Numerical simulation of the flow in a conduit, in the presence of a confined air cushion  

Science.gov (United States)

A rectangular conduit with a closed end has water flowing in/out at the other end. The water level at the open end has an imposed sinusoidal movement. When this level is higher than the ceiling of the conduit, a certain mass of air is trapped under the ceiling. In a previous article (T.D. Nguyen, La Houille Blanche, No. 2, 1990), it was supposed that this air is flowing out freely through the ceiling, so the relative pressure at the water surface is zero, and the water hammer at the dead end of the conduit was calculated when the conduit was thoroughly filled. In this article, it is supposed that the trapped air is compressed isothermally or adiabatically. The set of equations is resolved (water continuity and movement equations, air state equation) by supposing a regime of flow at each section (section submerged or not), a certain value for the air pressure and by using the sweep method to determine the water flow characteristics. The air volume calculated by iteration must converge, and the calculated regimes at each section (submerged or free) must agree with the supposed regimes. The simulation is performed first with a horizontal conduit then with an inclined conduit. As expected, adiabatic compression gives higher pressure than isothermal compression. The simulation shows also that when there is an air cushion, compared with the case when air is flowing out freely, the shock of the water hammer at the closed end of the conduit is significantly reduced. This method is aimed at calculating the flow with entrapped air in the inlet/outlet tunnel of a hydroelectric plant, or in sewer system pipe when a sudden discharge surge (due to turbin opening/closing or to urban storm) changes a previously free-surface flow in a mostly full-pipe flow, but with some air entrapped under the ceiling. Copyright

Nguyen, Trieu Dong

1999-02-01

202

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Ortiz, Marcos German (Idaho Falls, ID)

1998-01-01

203

Stability, protection and ac loss of cable-in-conduit conductors - a designer's approach  

Energy Technology Data Exchange (ETDEWEB)

Stability margin, ac response (losses and current distribution) and protection issues (hot-spot temperature and maximum quench pressure) are the three primary aspects considered in the design of a superconducting magnet for application in an experimental fusion reactor. This paper reviews these three aspects in particular for cable-in-conduit conductors (CICCs). Their combination, together with the requirements on the performance of the magnet, determines a set of constraints to be satisfied at all operating points. This can be achieved only by means of compromises in the design, e.g. selecting the material fractions in the cable as a function of the specified margin and of the achievable current density. Here are presented some of the basic guidelines to be used for an effective design of a CICC, based in particular on simplified stability and hot-spot models. (orig.).

Bottura, L. (Max-Planck-Inst. fuer Plasmaphysik, Garching (Germany)); NET Team

1993-01-01

204

Percutaneous balloon dilation of Carpentier-Edwards porcine-valved right ventricle-to-pulmonary artery conduits.  

Science.gov (United States)

Right ventricular outflow tract (RVOT) conduit stenosis remains a significant problem for patients with right ventricle-to-pulmonary artery (RV-to-PA) conduits placed as palliation for congenital heart disease. Previous reports on balloon dilation of RVOT conduits all describe small series with varying levels of success during limited follow-up evaluation. This study reviewed all patients with RV-to-PA conduits who underwent percutaneous balloon dilation for conduit stenosis at the authors' institution from 2000 to 2011. Patients with Carpentier-Edwards (CE) model 4300 porcine-valved conduits (Edwards Lifesciences Corp., Irvine, CA) (n = 19) were compared with patients who had all other types of conduits (n = 19). Successful balloon angioplasty was defined as a 20 % decrease in the RV-to-PA gradient, a 20 % decrease in the ratio of the RV systolic-to-aortic systolic pressure, or both. Balloon dilation was successful for 57.9 % of the patients with CE conduits and for 31.6 % of patients with other types of conduits (p = 0.10, Chi square test). Logistic regression analysis showed that balloon dilation was significantly more likely to be successful with CE valves than with other types (odds ratio [OR], 6.59; 95 % confidence interval [CI], 1.22-35.49). In a continuous series of patients with stenotic RV-to-PA conduits, the CE porcine-valved conduit was more amenable to percutaneous balloon dilation than other types of RV-to-PA conduits at the midterm follow-up evaluation. This has important ramifications in terms of valve selection for patients with congenital heart disease who will require surgical reintervention for RVOT stenosis. PMID:23229291

Hall, Amanda C; Miga, Daniel E; Leonard, Glenn T; Wang, Hongyue; Kavey, Rae-Ellen; Alfieris, George M

2012-12-11

205

Percutaneous balloon dilation of Carpentier-Edwards porcine-valved right ventricle-to-pulmonary artery conduits.  

UK PubMed Central (United Kingdom)

Right ventricular outflow tract (RVOT) conduit stenosis remains a significant problem for patients with right ventricle-to-pulmonary artery (RV-to-PA) conduits placed as palliation for congenital heart disease. Previous reports on balloon dilation of RVOT conduits all describe small series with varying levels of success during limited follow-up evaluation. This study reviewed all patients with RV-to-PA conduits who underwent percutaneous balloon dilation for conduit stenosis at the authors' institution from 2000 to 2011. Patients with Carpentier-Edwards (CE) model 4300 porcine-valved conduits (Edwards Lifesciences Corp., Irvine, CA) (n = 19) were compared with patients who had all other types of conduits (n = 19). Successful balloon angioplasty was defined as a 20 % decrease in the RV-to-PA gradient, a 20 % decrease in the ratio of the RV systolic-to-aortic systolic pressure, or both. Balloon dilation was successful for 57.9 % of the patients with CE conduits and for 31.6 % of patients with other types of conduits (p = 0.10, Chi square test). Logistic regression analysis showed that balloon dilation was significantly more likely to be successful with CE valves than with other types (odds ratio [OR], 6.59; 95 % confidence interval [CI], 1.22-35.49). In a continuous series of patients with stenotic RV-to-PA conduits, the CE porcine-valved conduit was more amenable to percutaneous balloon dilation than other types of RV-to-PA conduits at the midterm follow-up evaluation. This has important ramifications in terms of valve selection for patients with congenital heart disease who will require surgical reintervention for RVOT stenosis.

Hall AC; Miga DE; Leonard GT; Wang H; Kavey RE; Alfieris GM

2013-04-01

206

A conduit system distributes chemokines and small blood-borne molecules through the splenic white pulp.  

UK PubMed Central (United Kingdom)

Access to the splenic white pulp is restricted to lymphocytes and dendritic cells. Here we show that movement of molecules from the blood into these confined areas is also limited. Large molecules, such as bovine serum albumin (68 kD), immunoglobulin G (150 kD), and 500 kD dextran are unable to enter the white pulp, whereas smaller blood-borne molecules can directly permeate this compartment. The distribution is restricted to a stromal network that we refer to as the splenic conduit system. The small lumen of the conduit contains collagen fibers and is surrounded in the T cell areas by reticular fibroblasts that express ER-TR7. It also contains the chemokine CCL21. Conversely, in B cell follicles the B cell-attracting chemokine CXCL13 was found to be associated with the conduit and absence of ER-TR7+ fibroblasts. These results show heterogeneity of reticular fibroblasts that enfold the conduit system and suggest that locally produced chemokines are transported through and presented on this reticular network. Therefore, the conduit plays a role in distribution of both blood-borne and locally produced molecules and provides a framework for directing lymphocyte migration and organization of the splenic white pulp.

Nolte MA; Beliën JA; Schadee-Eestermans I; Jansen W; Unger WW; van Rooijen N; Kraal G; Mebius RE

2003-08-01

207

A conduit system distributes chemokines and small blood-borne molecules through the splenic white pulp.  

Science.gov (United States)

Access to the splenic white pulp is restricted to lymphocytes and dendritic cells. Here we show that movement of molecules from the blood into these confined areas is also limited. Large molecules, such as bovine serum albumin (68 kD), immunoglobulin G (150 kD), and 500 kD dextran are unable to enter the white pulp, whereas smaller blood-borne molecules can directly permeate this compartment. The distribution is restricted to a stromal network that we refer to as the splenic conduit system. The small lumen of the conduit contains collagen fibers and is surrounded in the T cell areas by reticular fibroblasts that express ER-TR7. It also contains the chemokine CCL21. Conversely, in B cell follicles the B cell-attracting chemokine CXCL13 was found to be associated with the conduit and absence of ER-TR7+ fibroblasts. These results show heterogeneity of reticular fibroblasts that enfold the conduit system and suggest that locally produced chemokines are transported through and presented on this reticular network. Therefore, the conduit plays a role in distribution of both blood-borne and locally produced molecules and provides a framework for directing lymphocyte migration and organization of the splenic white pulp. PMID:12900524

Nolte, Martijn A; Beliën, Jeroen A M; Schadee-Eestermans, Inge; Jansen, Wendy; Unger, Wendy W J; van Rooijen, Nico; Kraal, Georg; Mebius, Reina E

2003-08-01

208

Evaluation of a multi-layer microbraided polylactic acid fiber-reinforced conduit for peripheral nerve regeneration.  

Science.gov (United States)

We evaluated peripheral nerve regeneration using a biodegradable multi-layer microbraided polylactic acid (PLA) fiber-reinforced conduit. Biodegradability of the PLA conduit and its effectiveness as a guidance channel were examined as it was used to repair a 10 mm gap in the rat sciatic nerve. As a result, tube fragmentation was not obvious and successful regeneration through the gap occurred in all the conduits at 8 weeks after operation. These results indicate the superiority of the PLA materials and suggest that the multi-layer microbraided PLA fiber-reinforced conduits provide a promising tool for neuro-regeneration. PMID:19115095

Lu, Ming-Chin; Huang, Yen-Ting; Lin, Jia-Horng; Yao, Chun-Hsu; Lou, Ching-Wen; Tsai, Chin-Chuan; Chen, Yueh-Sheng

2008-12-30

209

Evaluation of a multi-layer microbraided polylactic acid fiber-reinforced conduit for peripheral nerve regeneration.  

UK PubMed Central (United Kingdom)

We evaluated peripheral nerve regeneration using a biodegradable multi-layer microbraided polylactic acid (PLA) fiber-reinforced conduit. Biodegradability of the PLA conduit and its effectiveness as a guidance channel were examined as it was used to repair a 10 mm gap in the rat sciatic nerve. As a result, tube fragmentation was not obvious and successful regeneration through the gap occurred in all the conduits at 8 weeks after operation. These results indicate the superiority of the PLA materials and suggest that the multi-layer microbraided PLA fiber-reinforced conduits provide a promising tool for neuro-regeneration.

Lu MC; Huang YT; Lin JH; Yao CH; Lou CW; Tsai CC; Chen YS

2009-05-01

210

Improvements to vapor generators  

International Nuclear Information System (INIS)

[en] A supporting system is proposed for vapor generators of the 'supported' type. Said supporting system is intended to compensate the disparities of thermal expansion due to the differences in the vertical dimensions of the tubes in the walls of the combustion chamber and their collectors compared to that of the balloon tanks and the connecting tube clusters of vaporization, the first one being longer than the second ones. Said system makes it possible to build said combustion chamber higher than the balloon tanks and the tube clusters of vaporization. The capacity of steam production is thus enhanced

1975-03-17

211

A 6-year experience with radial artery conduit for myocardial revascularization  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Excellent long-term patencies of arterial grafts are considered, superior to those of vein grafts. In this study, we present our 6 years experience in using radial artery as a conduit for myocardial revascularization. The aim of the present study was to assess the safety and early and mid term results of using radial artery in coronary artery bypass graft. Methods: The radial artery used as a conduit in 308 cases was evaluated during past 6 years, and the results obtained were processed and analyzed. Results: The operative morbidity comprised re-operation for bleeding in 3.2%, MI in 5%, with paresthesis and stitch abscess of the hand in 10% in and 3.5% respectively. Hospital mortality included 2 patients, one case being directly due to complication of harvesting radial artery.Conclusion: The results of present study were satisfactory with acceptable morbidity and mortality and favored the application of this conduit to CABG patients.

A Sadeghpour-Tabaee; A Rostami; S Arefi

2007-01-01

212

Conduits Mediate Transport of Low Molecular Weight Antigen to Lymph Node Follicles  

Science.gov (United States)

Summary Recent studies report that B cells acquire large lymph-borne antigens and immune complexes directly from subcapsular sinus macrophages while small antigens appear to diffuse directly into the B cell follicles. To directly compare entrance of large and small Ags into the follicles, we used multiphoton intravital microscopy to track drainage of Ag into the peripheral lymph nodes and subsequent encounter by B cells and follicular dendritic cells in the underlying follicles. We find that a system of conduits extends into the follicles and mediates delivery of small antigens to cognate B cells and follicular dendritic cells. The follicular conduits provide an efficient and rapid mechanism for delivery of small antigens to B cells, which directly contact the CXCL13 chemokine-enriched conduits. By contrast, large antigens were bound by subcapsular sinus macrophages and subsequently transferred to follicular B cells as previously reported.

Roozendaal, Ramon; Mempel, Thorsten R.; Pitcher, Lisa A.; Gonzalez, Santiago F.; Verschoor, Admar; Mebius, Reina E.; von Andrian, Ulrich H.; Carroll, Michael C.

2009-01-01

213

Conduits mediate transport of low-molecular-weight antigen to lymph node follicles.  

UK PubMed Central (United Kingdom)

To track drainage of lymph-borne small and large antigens (Ags) into the peripheral lymph nodes and subsequent encounter by B cells and follicular dendritic cells, we used the approach of multiphoton intravital microscopy. We find a system of conduits that extend into the follicles and mediate delivery of small antigens to cognate B cells and follicular dendritic cells. The follicular conduits provide an efficient and rapid mechanism for delivery of small antigens and chemokines such as CXCL13 to B cells that directly contact the conduits. By contrast, large antigens were bound by subcapsular sinus macrophages and subsequently transferred to follicular B cells as previously reported. In summary, the findings identify a unique pathway for the channeling of small lymph-borne antigens and chemoattractants from the subcapsular sinus directly to the B cell follicles. This pathway could be used for enhancing delivery of vaccines or small molecules for improvement of humoral immunity.

Roozendaal R; Mempel TR; Pitcher LA; Gonzalez SF; Verschoor A; Mebius RE; von Andrian UH; Carroll MC

2009-02-01

214

Conduits mediate transport of low-molecular-weight antigen to lymph node follicles.  

Science.gov (United States)

To track drainage of lymph-borne small and large antigens (Ags) into the peripheral lymph nodes and subsequent encounter by B cells and follicular dendritic cells, we used the approach of multiphoton intravital microscopy. We find a system of conduits that extend into the follicles and mediate delivery of small antigens to cognate B cells and follicular dendritic cells. The follicular conduits provide an efficient and rapid mechanism for delivery of small antigens and chemokines such as CXCL13 to B cells that directly contact the conduits. By contrast, large antigens were bound by subcapsular sinus macrophages and subsequently transferred to follicular B cells as previously reported. In summary, the findings identify a unique pathway for the channeling of small lymph-borne antigens and chemoattractants from the subcapsular sinus directly to the B cell follicles. This pathway could be used for enhancing delivery of vaccines or small molecules for improvement of humoral immunity. PMID:19185517

Roozendaal, Ramon; Mempel, Thorsten R; Pitcher, Lisa A; Gonzalez, Santiago F; Verschoor, Admar; Mebius, Reina E; von Andrian, Ulrich H; Carroll, Michael C

2009-01-29

215

Biodegradable conduit small gap tubulization for peripheral nerve mutilation: a substitute for traditional epineurial neurorrhaphy.  

UK PubMed Central (United Kingdom)

Nerve regeneration and re-innervation are usually difficult after peripheral nerve injury. Epineurium neurorrhaphy to recover the nerve continuity is the traditional choice of peripheral nerve mutilation without nerve defects, whereas the functional recovery remains quite unsatisfactory. Based on previous research in SD rats and Rhesus Monkeys, a multiple centers clinical trial about biodegradable conduit small gap tubulization for peripheral nerve mutilation to substitute traditional epineurial neurorrhaphy was carried out. Herein, the authors reviewed the literature that focused on peripheral nerve injury and possible clinical application, and confirmed the clinical possibilities of biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation. The biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation may be a revolutionary innovation in peripheral nerve injury and repair field.

Zhang P; Han N; Wang T; Xue F; Kou Y; Wang Y; Yin X; Lu L; Tian G; Gong X; Chen S; Dang Y; Peng J; Jiang B

2013-01-01

216

Capacitive effect of cavitation in xylem conduits: results from a dynamic model.  

Science.gov (United States)

Embolisms decrease plant hydraulic conductance and therefore reduce the ability of the xylem to transport water to leaves provided that embolized conduits are not refilled. However, as a xylem conduit is filled with gas during cavitation, water is freed to the transpiration stream and this transiently increases xylem water potential. This capacitive effect of embolism formation on plant function has not been explicitly quantified in the past. A dynamic model is presented that models xylem water potential, xylem sap flow and cavitation, taking into account both the decreasing hydraulic conductance and the water release effect of xylem embolism. The significance of the capacitive effect increases in relation to the decreasing hydraulic conductance effect when transpiration rate is low in relation to the total amount of water in xylem conduits. This ratio is typically large in large trees and during drought. PMID:19076529

Hölttä, Teemu; Cochard, Herve; Nikinmaa, Eero; Mencuccini, Maurizio

2009-01-01

217

Transverse colon conduit urinary diversion in patients treated with very high dose pelvic irradiation  

Energy Technology Data Exchange (ETDEWEB)

Urinary diversion may be required in patients receiving pelvic irradiation for gynaecological or genitourinary cancers either as part of a planned or salvage surgical procedure or for urological complications of irradiation. Records were reviewed for 30 such patients who underwent transverse colon conduit as a primary form of urinary diversion. Most of the conduits were constructed using refluxing ureterocolic anastomoses with stents. The results showed no operative mortality. Although the procedure was associated with a complication rate of 37% and a re-operation rate of 20%, there were no bowel or urinary anastomotic leaks. The operation could be safely performed on patients with renal failure, with 83% of such patients showing normal or improved serum creatinine levels post operatively. The advantages of transverse colon conduit urinary diversion are the use of non-irradiated bowel and ureters for diversion. It is recommended as a primary form of urinary diversion in these high risk cases. (Author).

Ravi, R.; Dewan, A.K. (Cancer Inst. (WIA), Adyar, Madras (India)); Pandey, K.K. (Safdarjang Hospital, New Delhi (India))

1994-01-01

218

Autologous pericardial pulmonary conduit with single point attached commissures in a sheep model.  

UK PubMed Central (United Kingdom)

OBJECTIVE: For the surgical treatment of congenital heart disease and in Ross procedure a valved conduit is frequently required. Since homografts are not readily available in every country, a reliable alternative is needed. We developed a novel technique to construct a valved pulmonary conduit with single point attached commissures (SPAC) in a simple and fast way from a small strip of autologous pericardium, molded and briefly treated with glutaraldehyde. METHODS: Autologous pericardial pulmonary conduit was constructed intraoperatively and implanted in pulmonary position in a beating heart in six sheep. The prosthesis size was 31 mm for all sheep and the construction time (including 10 min glutaraldehyde treatment) was 19.0+/-3.3 min. Implantation time and cardiopulmonary by-pass was 27.3+/-5.4 min and 40.5+/-7.7 min, respectively. The sheep were euthanized after 6 months (222.7+/-5.8 days) postoperatively. RESULTS: In all sheep, the autologous pericardial valve was immediately competent. At sacrifice, the pericardial valve was pliable and competent in all cases with SPAC well anchored to the pericardial conduit wall. The maximum transvalvular gradient at implant and at sacrifice was 3.3+/-2.8 mmHg and 3.3+/-2.0 mmHg, respectively. CONCLUSIONS: This novel autologous pericardial pulmonary conduit with SPAC can be reliably produced in a very short time intraoperatively before cardiopulmonary by-pass. The simplicity of construction, biocompatibility and freedom of stenosis or thrombosis makes this autologous pulmonary conduit especially useful for patients at locations where homografts are not readily available.

Goetz WA; Tan TE; Lim KH; Xiong F; Salgues Sle H; Grousson N; Chua YL; Yeo JH

2008-01-01

219

Spatially resolved information on karst conduit flow from in-cave dye-tracing  

Science.gov (United States)

Artificial tracers are powerful tools to investigate karst systems. Tracers are commonly injected into sinking streams or dolines, while springs serve as monitoring sites. The obtained flow and transport parameters represent mixed information from the vadose, epiphreatic and phreatic zones, i.e., the aquifer remains a black box. Accessible active caves constitute valuable but underexploited natural laboratories to gain detailed insights into the hydrologic functioning of the aquifer. Two multi-tracer tests in the catchment of a major karst spring (Blautopf, Germany) with injections and monitoring in two associated water caves aimed at obtaining spatially and temporally resolved information on groundwater flow in different compartments of the system. Two tracers were injected in the caves to characterize the hydraulic connections between them and with the spring. Two injections at the land surface, far from the spring, aimed at resolving the aquifer's internal drainage structure. Tracer breakthrough curves were monitored by field fluorimeters in caves and at the spring. Results demonstrate the dendritic drainage structure of the aquifer. It was possible to obtain relevant flow and transport parameters for different sections of this system. The highest mean flow velocities (275 m h-1) were observed in the near-spring epiphreatic section (open-channel flow), while velocities in the phreatic zone (pressurized flow) were one order of magnitude lower. Determined conduit water volumes confirm results of water balances and hydrograph analyses. In conclusion, experiments and monitoring in caves can deliver spatially resolved information on karst aquifer heterogeneity and dynamics that cannot be obtained by traditional investigative methods.

Lauber, U.; Ufrecht, W.; Goldscheider, N.

2013-09-01

220

The no-touch saphenous vein as the preferred second conduit for coronary artery bypass grafting.  

UK PubMed Central (United Kingdom)

BACKGROUND: Injury incurred while saphenous veins are being obtained results in poor graft patency and impairs the results of coronary artery bypass grafting. A novel method of obtaining veins, the no-touch technique, has shown improved long-term saphenous vein graft patency. METHODS: This randomized trial included 108 patients undergoing coronary artery bypass grafting and compared the patency of no-touch saphenous vein with that of radial artery grafts. Each patient was assigned to receive one no-touch saphenous vein and one radial artery graft to either the left or the right coronary territory to complement the left internal thoracic artery. RESULTS: Angiography was performed in 99 patients (92%) at a mean of 36 months postoperatively. Graft and grafted coronary artery patency was evaluated. The patency of grafts for no-touch saphenous vein and radial artery was 94% versus 82% (p = 0.01), respectively. The patency of coronary arteries grafted with no-touch saphenous vein and radial artery grafts was 95% versus 84% (p = 0.005), respectively. Eighty-nine of 96 (93%) left internal thoracic artery grafts were patent. CONCLUSIONS: No-touch saphenous vein grafts showed a significantly higher patency rate than the radial artery grafts and the patency was comparable to the patency for left internal thoracic artery grafts. This highlights the improvement in saphenous vein graft quality with the no-touch technique and increases the number of situations in which saphenous veins may be preferable to radial artery grafts as conduits in coronary artery bypass grafting.

Dreifaldt M; Mannion JD; Bodin L; Olsson H; Zagozdzon L; Souza D

2013-07-01

 
 
 
 
221

Quench propagation in a cable-in-conduit force-cooled superconductor; Preliminary results  

Energy Technology Data Exchange (ETDEWEB)

Cable-in-conduit force-cooled superconductor is being considered for use in a superconducting magnetic energy storage (SMES) system. The quench behavior of such a conductor plays a very important role in the protection of this system and of other magnets having similar cooling environments. In particular, the existence of the thermohydraulic quenchback effect predicted recently by numerical analysis and theoretical calculation has been investigated experimentally. The test sample consists of a 509-m-long single triplex NbTi superconductor enclosed in a stainless steel conduit. This paper reports the test results and the comparison with predictions.

Lue, J.W.; Schwenterly, S.W.; Dresner, L.; Lubell, M.S. (Oak Ridge National Lab., TN (United States))

1991-03-01

222

Aspects that aid decisions for replacement or further maintenance of individual pipe conduits  

Energy Technology Data Exchange (ETDEWEB)

Justification for replacement of pipe conduits should be made subject to objective criteria to ensure that the most urgent projects will be included in plans for renewal. As far as it is possible, economic aspects should also play an important role. To judge the repair expenditures properly that are to be expected, information on already recorded pipe damage, and findings on the conditions of the conduits, must be used. In addition to aspects of economic rationality, security and the reputation of the enterprise must also be considered.

Hofer, P.

1983-04-01

223

Small scale high resolution LiDAR measurements of a subglacial conduit  

Science.gov (United States)

We present direct measurements of surface roughness in a sub-glacial conduit system underneath the Rieperbreen Glacier, Svalbard, Norway. Data was collected with a low-cost (129 USD) Microsoft Kinect video game device used as a LIDAR sensor. Surface roughness is a primary control on water flow in rivers, channels, and cave conduit systems and understanding the effects of surface roughness on water flow has been problematic due to lack of direct measurements of roughness in natural systems. We use the ice scallop dimensions to derive flow velocity and explore implications of the changing roughness parameters as the cave grows and shrinks.

Mankoff, K. D.; Gulley, J.

2012-04-01

224

Ecoulements intermittents de gaz et de liquide en conduite verticale Intermittent Gas and Liquid Flows in a Vertical Pipe.  

Directory of Open Access Journals (Sweden)

Full Text Available Le modèle présenté ici permet la pré-détermination du gradient de pression, du taux global de gaz, et de grandeurs caractéristiques de l'intermittence, dans un écoulement à poches et bouchons en conduite verticale. L'écriture des lois de conservation en moyenne phasique conditionnelle conduit à la définition d'une cellule moyenne équivalente. La fermeture du modèle est assurée par des lois de contrainte de cisaillement film-paroi, film-poche, bouchon-paroi, par une loi d'arrachage du gaz au culot de la poche, une loi de glissement du gaz dans les bouchons et par une loi de la vitesse moyenne de propagation des fronts de poches. Le calibrage et la qualification du modèle s'appuient sur deux banques de données, dont l'une a été obtenue avec des fluides pétroliers dans des conditions proches des situations industrielles (boucle diphasique de Boussens). The model described here can be used to predetermine the pressure gradient, the overall gas rate and the characteristic intermittence magnitudes in pocket and slug flow in a vertical pipe. The way governing equations in the conditional phase average are written defines an equivalent average cell. The model is closed by film/wall, film/pocket and slug/wall shear-stress laws, by a pulloff law for the gas at the bottom of the pocket, a slippage law for the gas in the slugs, and a mean propagation velocity law for the pocket fronts. The calibration and qualification of the model are based on two data banks, one of which contains data on petroleum fluids under conditions close to industrial situations (two-phase loop at Boussens).

Line A.; Masbernat L.

2006-01-01

225

Use of the Melody™ transcatheter pulmonary valve as a "covered stent" to repair conduit perforation during pulmonary valve implantation.  

UK PubMed Central (United Kingdom)

Right ventricular to pulmonary artery conduit tear after balloon dilation is a recognized potential complication, which can, in theory, be treated with a covered stent. We describe use of the Melody™ valve as a so-called "covered" stent for containment of bleeding from RV-PA conduit tear.

Mahgerefteh J; Sutton NJ; Pass RH

2013-05-01

226

Reconstrução arterial com tubo de pericárdio bovino corrugado/ Arterial reconstruction with crimped bovine pericardial conduit  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese No período de agosto de 1989 a fevereiro de 1992, 32 pacientes foram submetidos a reconstruções vasculares utilizando-se condutos de pericárdio bovino corrugado preservado em glutaraldeído. A incorporação do principio crimping utilizado nas próteses vasculares sintéticas proporcionou tubos que mantêm sua forma cilíndrica, mesmo quando submetidos a curvaturas. Vinte e nove pacientes (Grupo I) eram portadores de doenças da aorta torácica e/ou abdominal, incluin (more) do aneurismas, dissecções agudas, coarctação da aorta e lesão oclusiva aorto-ilíaca. A reconstrução da aorta torácica foi realizada em 25 pacientes (incluindo a substituição da valva aórtica em 10), da aorta abdominal em 2 e aorto-ilíaca em 2. Três pacientes (Grupo II), portadores de cardiopatias congênitas complexas, foram submetidos a reconstrução da via de saída do ventrículo direito em 2 e a operação de Fontan em 1. A mortalidade hospitalar no Grupo I foi 24% (7 pacientes), causada por baixo débito cardíaco em 4, recidiva precoce da dissecção em dois e infecção respiratória em 1. Seis destes óbitos ocorreram em pacientes operados na fase aguda de dissecção aórtica. Não houve nenhum óbito no Grupo II. Houve um óbito tardio no Grupo I devido a complicações metabólicas relacionadas a diabetes e insuficiência renal crônica. Esta experiência clínica inicial registrou um seguimento médico de 16 meses por paciente, com um máximo de 32 meses e não se verificou nenhuma complicação tardia relacionada ao conduto de pericárdio bovino corrugado. Abstract in english From August 1989 to February 1992, 32 patients underwent vascular reconstructions using crimped bovine pericardial conduits processed in glutaraldehyde. The introduction of the crimping process used for synthetic vascular prosthesis provided circular tubes, which retain their shape with bending and avoid kinking. Twenty-nine patients (Group I) presented vascular lesions involving the thoracic and/or abdominal aorta, including aneurysms, acute dissections, coarctation and (more) aorto-iliac lesion. The thoracic aortic reconstruction was performed in 25 patients, including aortic valve replacement in 10, the abdominal aorta in 2, and the aortic bifurcation in 2. Three patients (Group II) with complex congenital heart lesions underwent reconstruction of the right ventricular outflow tract in 2, and the Fontan operation in 1. Hospital mortality in Group I was 24% (7 patients). Causes of death were low cardiac output in 4, recurrence of aortic dissection in 2 and respiratory infection in 1. Six of them had been operated upon as emergencies due to acute aortic dissection. All patients in group II survived the operation. There was 1 late death in group I due to methabolic complications related to diabetes and chronic renal failure. This initial clinical experience showed a mean follow-up of 16 months per patient and the longest follow-up was 32 months. It was not observed any late complication related to the crimped bovine pericardial conduit up-to-date.

Salles, Cláudio A; Ribeiro, Nilzo A. M; Kalil, Renato A. K; Vieira, Gilberto Lino; Souza, Liberato S. S; Borém, Paulo M; Andrade, Miguel E. C; Faleiros, Rogério D; Andrade Jr, Marcos A. M

1992-06-01

227

Thermal electric vapor trap arrangement and method  

Energy Technology Data Exchange (ETDEWEB)

A technique for trapping vapor within a section of a tube is disclosed herein. This technique utilizes a conventional, readily providable thermal electric device having a hot side and a cold side and means for powering the device to accomplish this. The cold side of this device is positioned sufficiently close to a predetermined section of the tube and is made sufficiently cold so that any condensable vapor passing through the predetermined tube section is condensed and trapped, preferably within the predetermined tube section itself.

Alger, Terry (Tracy, CA)

1988-01-01

228

Sickle cell anemia is associated with reduced nitric oxide bioactivity in peripheral conduit and resistance vessels.  

UK PubMed Central (United Kingdom)

The purpose of the study was to examine endothelium-dependent and -independent vasodilation of conduit and resistance vessels in sickle cell anemia (HbSS). We measured the effects of intra-arterial infusion of methacholine, sodium nitroprusside, and NG-monomethyl-L-arginine (L-NMMA) on forearm blood flow using venous occlusion plethysmography in eight patients with HbSS and 11 HbAA controls. We assessed vasodilation of the conduit brachial artery using ultrasound in 17 patients with HbSS and 41 nonanemic controls. Forearm blood flow response to methacholine was similar in HbSS and HbAA, while the response to sodium nitroprusside was greater in those with HbSS. Nitric oxide synthase inhibition with L-NMMA attenuated methacholine-induced forearm blood flow to a lesser extent in HbSS compared to HbAA, suggesting diminished nitric oxide (NO) contribution to endothelium-dependent vasodilation. Flow-mediated and nitroglycerin-induced dilation were impaired in HbSS compared to controls and were not affected by the antioxidant vitamin C or the precursor substrate for NO synthesis L-arginine. NO bioactivity is reduced but differs in peripheral conduit and resistance vessels in HbSS. Resistance vessels have preserved response to exogenous NO donors but have diminished contribution of NO to endothelium-dependent vasodilation. Conduit vessels demonstrate impaired vasodilation to endogenous and exogenous NO.

Eberhardt RT; McMahon L; Duffy SJ; Steinberg MH; Perrine SP; Loscalzo J; Coffman JD; Vita JA

2003-10-01

229

Sickle cell anemia is associated with reduced nitric oxide bioactivity in peripheral conduit and resistance vessels.  

Science.gov (United States)

The purpose of the study was to examine endothelium-dependent and -independent vasodilation of conduit and resistance vessels in sickle cell anemia (HbSS). We measured the effects of intra-arterial infusion of methacholine, sodium nitroprusside, and NG-monomethyl-L-arginine (L-NMMA) on forearm blood flow using venous occlusion plethysmography in eight patients with HbSS and 11 HbAA controls. We assessed vasodilation of the conduit brachial artery using ultrasound in 17 patients with HbSS and 41 nonanemic controls. Forearm blood flow response to methacholine was similar in HbSS and HbAA, while the response to sodium nitroprusside was greater in those with HbSS. Nitric oxide synthase inhibition with L-NMMA attenuated methacholine-induced forearm blood flow to a lesser extent in HbSS compared to HbAA, suggesting diminished nitric oxide (NO) contribution to endothelium-dependent vasodilation. Flow-mediated and nitroglycerin-induced dilation were impaired in HbSS compared to controls and were not affected by the antioxidant vitamin C or the precursor substrate for NO synthesis L-arginine. NO bioactivity is reduced but differs in peripheral conduit and resistance vessels in HbSS. Resistance vessels have preserved response to exogenous NO donors but have diminished contribution of NO to endothelium-dependent vasodilation. Conduit vessels demonstrate impaired vasodilation to endogenous and exogenous NO. PMID:14508796

Eberhardt, Robert T; McMahon, Lillian; Duffy, Stephen J; Steinberg, Martin H; Perrine, Susan P; Loscalzo, Joseph; Coffman, Jay D; Vita, Joseph A

2003-10-01

230

Accounting for the kinetic energy losses with air movement through a conduit with permeable walls  

Energy Technology Data Exchange (ETDEWEB)

An energy equation of flux is given. The conditions in which the kinetic energy losses in air drafts may be ignored are determined. Formulae are given for calculating the draft coefficient in the flexible ventilation conduit used to ventilate development workings in coal mines.

Kazakov, S.P.; Cherkasov, V.S.

1980-01-01

231

Modifications to the Conduit Flow Process Mode 2 for MODFLOW-2005.  

Science.gov (United States)

As a result of rock dissolution processes, karst aquifers exhibit highly conductive features such as caves and conduits. Within these structures, groundwater flow can become turbulent and therefore be described by nonlinear gradient functions. Some numerical groundwater flow models explicitly account for pipe hydraulics by coupling the continuum model with a pipe network that represents the conduit system. In contrast, the Conduit Flow Process Mode 2 (CFPM2) for MODFLOW-2005 approximates turbulent flow by reducing the hydraulic conductivity within the existing linear head gradient of the MODFLOW continuum model. This approach reduces the practical as well as numerical efforts for simulating turbulence. The original formulation was for large pore aquifers where the onset of turbulence is at low Reynolds numbers (1 to 100) and not for conduits or pipes. In addition, the existing code requires multiple time steps for convergence due to iterative adjustment of the hydraulic conductivity. Modifications to the existing CFPM2 were made by implementing a generalized power function with a user-defined exponent. This allows for matching turbulence in porous media or pipes and eliminates the time steps required for iterative adjustment of hydraulic conductivity. The modified CFPM2 successfully replicated simple benchmark test problems. PMID:21371024

Reimann, Thomas; Birk, Steffen; Rehrl, Christoph; Shoemaker, W Barclay

2011-03-03

232

A new engineering scheme for coal conduits in large hydraulic mines  

Energy Technology Data Exchange (ETDEWEB)

New variations that were developed for different back-up conditions for a coal conduit with controlled hydraulic reservoirs in pumping stages in a closed cycle, and a reversal of the field or the entire pipeline in breakdown conditions are given.

Geier, V.G.; Borisov, A.A.; Mokryi, G.V.

1980-01-01

233

Modelling of dual stability in a cable-in-conduit conductor.  

Science.gov (United States)

A zero dimensional stability model has been developed for cable-in-conduit superconductors. The model is effective in simulating the multi-valued stability behaviour in the vicinity of the limiting current. This has been by modifying the helium heat trans...

L. Bottura J. V. Minervini

1990-01-01

234

Lymphatic pump-conduit duality: contraction of postnodal lymphatic vessels inhibits passive flow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lymphangions, the segments of lymphatic vessels between valves, exhibit structural characteristics in common with both ventricles and arteries. Although once viewed as passive conduits like arteries, it has become well established that lymphangions can actively pump lymph against an axial pressure g...

Quick, Christopher M.; Ngo, Bruce L.; Venugopal, Arun M.; Stewart, Randolph H.

235

Local recurrence of bladder cancer after cystectomy with orthotopic bladder substitution and ileal conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: To present the local recurrence rates after radical cystectomy for advanced bladder cancer and to compare them between patients with orthotopic neobladder and ileal conduit. Patients and methods: 97 patients with radical cystectomy were analyzed: 75 patients with orthotopic ileal neobladd...

Pej?i? T.; Hadži-?oki? J.; A?imovi? M.; Markovi? B.B.; Maksimovi? H.M.; Milkovi? B.; Kajmakovi? B.

236

A 10-cm big stone formed in ileal conduit six years after cystectomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

INTRODUCTION: Ileal conduit (IC) is the standard urinary diversion following radical cystectomy. The formation of stone in the IC is one of the relatively common late complications of the procedure. CASE REPORT: The case of 69-year-old man who developed 10-cm large stone in the IC, six years afte...

Topuzovi? ?edomir; Pej?i? Tomislav; ?uraši? Ljubomir; Hadži-?oki? Jovan

237

Bronchovascular Reconstruction With a Bovine Pericardial Conduit and Surgical Reintervention Due to Thrombosis With Revascularisation.  

UK PubMed Central (United Kingdom)

We present the case of a 57-year-old male with left hilar squamous cell carcinoma infiltrating the pulmonary artery and in whom a sleeve bronchoplasty and angioplasty were performed using a bovine pericardial conduit. Three days post-operatively, graft thrombosis was detected; thrombectomy and graft reconstruction were performed with revascularisation of the graft.

Peña E; Blanco M; Otero T

2013-07-01

238

Effect of combined locally delivered growth factors and systemic sildenafil citrate on microrecanalization in biodegradable conduit for vas deferens reconstruction.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the effect of the combination of locally delivered growth factors and oral sildenafil citrate on cross-conduit microrecanalization. METHODS: A total of 42 rats were divided into 7 groups. Of the 42 rats, 6 underwent bilateral vasectomy and bilateral end-to-end vasovasostomy and 12 underwent bilateral vasectomy. Of the latter 12, 6 received sildenafil citrate orally (10 mg/kg/d) for 24 weeks and 6 received placebo. A total of 24 rats underwent bilateral vasectomy and bilateral reconstruction with implantation of a 5-mm biodegradable conduit that bridged the 2 vasal ends. Of the 24 rats with conduits, 12 also had 250 pg of transforming growth factor-? and 12.5 pg of platelet-derived growth factor-? sustained release nanoparticles placed in immediate proximity to the conduit. The remaining 12 rats with conduits (6 without growth factors and 6 with growth factors) also received sildenafil citrate orally (10 mg/kg/d) for 24 weeks; the others received placebo. The reconstructed segments were harvested for histologic examination at 24 weeks. RESULTS: Five of 6 primary vasovasostomy and no vasectomy-only rats sired litters. Significantly more microcanals per conduit were observed in rats receiving sildenafil citrate: without growth factors, 3.9 vs. 0 canals/conduit (P < 0.001); with growth factors, 5.5 vs. 0.25 canals/conduit (P < 0.001). The rats receiving sildenafil citrate with growth factors showed a trend toward more microcanals per conduit than the rats receiving sildenafil citrate without growth factors (5.5 vs 3.9; P = .10). Rats receiving growth factors but no sildenafil citrate did not produce more canals than the rats receiving neither growth factor nor sildenafil citrate (0.25 vs 0; P = NS). CONCLUSION: Orally administered sildenafil citrate enhances formation of microcanalization after postvasectomy reconstruction using a biodegradable conduit in a rat model. Locally delivered growth factors appear to increase the number of microcanals.

Rosevear HM; Krishnamachari Y; Ariza CA; Mallapragada SK; Salem AK; Griffith TS; De Young BR; Wald M

2012-04-01

239

Monolithic microwave integrated circuit water vapor radiometer  

Science.gov (United States)

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

1991-12-01

240

Cooking system with closed loop heat transfer means  

Energy Technology Data Exchange (ETDEWEB)

A cooking system is described comprising a cooking element for receiving food to be cooked; heat generating means; a sealed closed loop circuit; the closed loop circuit including a heating and vaporization zone, the heat generating means comprising a gaseous fuel fired radiant burner, and the heating and vaporization zone.

Scherer, R.M.

1987-04-28

 
 
 
 
241

Fabrication of Off-the-Shelf Multilumen Poly(Ethylene Glycol) Nerve Guidance Conduits Using Stereolithography.  

Science.gov (United States)

A manufacturing process for fabricating off-the-shelf multilumen poly(ethylene glycol) (PEG)-based nerve guidance conduits (NGCs) was developed that included the use of stereolithography (SL). A rapid fabrication strategy for complex 3D scaffolds incorporated postprocessing with lyophilization and sterilization to preserve the scaffold, creating an implantable product with improved suturability. SL is easily adaptable to changes in scaffold design, is compatible with various materials and cells, and can be expanded for mass manufacture. The fabricated conduits were characterized using optical and scanning electron microscopy, and measurements of swelling ratio, dimensional swelling factor, resistance to compression, and coefficient of friction were performed. Water absorption curves showed that the conduits after lyophilization and sterilization return easily and rapidly to a swollen state when placed in an aqueous solution, successfully maintaining their original overall structure as required for implantation. Postprocessed conduits at the swollen state were less slippery and therefore easier to handle than those without postprocessing. Suture pullout experiments showed that NGCs fabricated with a higher concentration of PEG were better able to resist suture pullout. NGCs having a multilumen design demonstrated a better resistance to compression than a single-lumen design with an equivalent surface area, as well as a greater force required to collapse the design. Conduits fabricated with a higher PEG concentration were shown to have compressive resistances comparable to those of commercially available NGCs. The use of SL with PEG and the manufacturing process developed here shows promise for improving the current state of the art in peripheral nerve repair strategies. PMID:20673135

Arcaute, Karina; Mann, Brenda K; Wicker, Ryan B

2010-08-30

242

Fabrication of Off-the-Shelf Multilumen Poly(Ethylene Glycol) Nerve Guidance Conduits Using Stereolithography.  

UK PubMed Central (United Kingdom)

A manufacturing process for fabricating off-the-shelf multilumen poly(ethylene glycol) (PEG)-based nerve guidance conduits (NGCs) was developed that included the use of stereolithography (SL). A rapid fabrication strategy for complex 3D scaffolds incorporated postprocessing with lyophilization and sterilization to preserve the scaffold, creating an implantable product with improved suturability. SL is easily adaptable to changes in scaffold design, is compatible with various materials and cells, and can be expanded for mass manufacture. The fabricated conduits were characterized using optical and scanning electron microscopy, and measurements of swelling ratio, dimensional swelling factor, resistance to compression, and coefficient of friction were performed. Water absorption curves showed that the conduits after lyophilization and sterilization return easily and rapidly to a swollen state when placed in an aqueous solution, successfully maintaining their original overall structure as required for implantation. Postprocessed conduits at the swollen state were less slippery and therefore easier to handle than those without postprocessing. Suture pullout experiments showed that NGCs fabricated with a higher concentration of PEG were better able to resist suture pullout. NGCs having a multilumen design demonstrated a better resistance to compression than a single-lumen design with an equivalent surface area, as well as a greater force required to collapse the design. Conduits fabricated with a higher PEG concentration were shown to have compressive resistances comparable to those of commercially available NGCs. The use of SL with PEG and the manufacturing process developed here shows promise for improving the current state of the art in peripheral nerve repair strategies.

Arcaute K; Mann BK; Wicker RB

2010-08-01

243

Vapor core propulsion reactors  

International Nuclear Information System (INIS)

Many research issues were addressed. For example, it became obvious that uranium tetrafluoride (UF4) is a most preferred fuel over uranium hexafluoride (UF6). UF4 has a very attractive vaporization point (1 atm at 1800 K). Materials compatible with UF4 were looked at, like tungsten, molybdenum, rhenium, carbon. It was found that in the molten state, UF4 and uranium attacked most everything, but in the vapor state they are not that bad. Compatible materials were identified for both the liquid and vapor states. A series of analyses were established to determine how the cavity should be designed. A series of experiments were performed to determine the properties of the fluid, including enhancement of the electrical conductivity of the system. CFD's and experimental programs are available that deal with most of the major issues.

1991-01-01

244

Speleogenetic effects of interaction between deeply derived fracture-conduit flow and intrastratal matrix flow in hypogene karst settings  

Directory of Open Access Journals (Sweden)

Full Text Available In carbonate rocks, especially in those with high primary porosity such as most Cenozoic carbonates, the interaction between deeply derived rising flow through sub-vertical fracture-controlled conduits and intrastratal matrix flow of shallower systems can invoke mixing cor- rosion and result in prominent speleogenetic effects. This paper outlines a conceptual model of such interaction and provides instructive field examples of relevant morphological effects from two different regions within the Prichernomorsky (north Black Sea) basin, where karst features are developed in lower Pliocene, Eocene and Paleocene limestones. In the Crimean fore-mountain region, extensive steep to ver- tical limestone scarps formed through recent exposure of hypogenic fracture-controlled conduits provide outstanding possibilities to directly examine details of the original karstic porosity. The morphological effects of the conduit/matrix interaction, documented in both caves and exposed scarps, include lateral widening of sub-vertical conduits within the interaction intervals (formation of lateral notches and niches) and the development of side bedding-parallel conduits, pockets and vuggy-spongework zones. Natural convection circulation, invoked by interaction of the two flow systems, spreads the morphological effects throughout the conduit space above the interaction interval. Where the interaction of the two flow systems is particularly strongly localized, such as along junctions of two vertical fracture sets, the resultant morphological effect can take the form of isolated chambers. The variety of speleogenetic features developed through the conduit/matrix interaction, can be broadly grouped into two categories: 1) variously shaped swells of the major fracture conduit itself (morphological fea- tures of its walls – niches and pockets), and 2) features of the vuggy-spongework halo surrounding the conduit. This halo includes clustered and stratiform cavities, spongework zones and lateral side conduits. The speleogenetic features due to conduit/matrix flow interaction, especially the halo forms, often demonstrate distinct asymmetry between opposite walls of the conduits. The prominent phenomenon of the vuggy-spongework halo around fracture-controlled conduits has important hydrogeological implications. A comparison of karst features in different regions and rock formations clearly shows that in spite of some distinctions imposed by local structural, sedimentological and paleo-hydrogeological peculiarities, hypogenic speleoforms in limestones of different age and of different degree of diagenetic maturity demonstrate remarkable similarities.

Klimchouk Alexander; Tymokhina Elizaveta; Amelichev Gennadiy

2012-01-01

245

Peripheral nerve regeneration using a microporous polylactic acid asymmetric conduit in a rabbit long-gap sciatic nerve transection model.  

UK PubMed Central (United Kingdom)

The performance of an asymmetric conduit made of microporous polylactic acid (PLA) in promoting the long-term peripheral nerve regeneration across a 20-mm-long sciatic nerve gap was evaluated by a rabbit sciatic nerve transection model. Magnetic resonance imaging (MRI) was employed to monitor the nerve regeneration process. The extents of nerve regeneration and conduit degradation were quantified by image analysis. Functional and histological analyses were followed to assess nerve reinnervation. MR images showed that the transected nerve was connected at about 4 months. The diameter of the regenerated nerve continued to increase while the conduit was gradually degraded. The conduit was completely degraded in 18 months. The degradation kinetics in vivo was estimated based on MR images. The functional recovery after 18 months was ?82% based on electrophysiology. The extension range of the operated limb was slowly recuperated to ?81% at 18 months. Histology showed that nerve bundles were self-assembled after 16-18 months, but the morphologies were still different from those of normal sciatic nerve. This was the first work on the long-term evaluation of peripheral nerve regeneration in a rabbit model, and the first to report the use of MRI to obtain the real-time images of regenerated nerve in a biomaterial conduit as well as to define the degradation rate of the conduit in vivo. The platform established in this study serves to evaluate the regeneration of larger-diameter (>3-mm) nerve across a long-gap bridged by a conduit.

Hsu SH; Chan SH; Chiang CM; Chen CC; Jiang CF

2011-05-01

246

Vapor Core Propulsion Reactors.  

Science.gov (United States)

Many research issues were addressed. For example, it became obvious that uranium tetrafluoride (UF4) is a most preferred fuel over uranium hexafluoride (UF6). UF4 has a very attractive vaporization point (1 atm at 1800 K). Materials compatible with UF4 we...

N. J. Diaz

1991-01-01

247

Muonium formation in vapors  

International Nuclear Information System (INIS)

The fractions of positive muons thermalizing in vapors as either the muonium atom (fsub(M)) or in diamagnetic environments (fsub(D)) have been measured in water, methanol, hexane, c-hexane, the chlorinated methanes and in TMS, in the pressure range from approximately 0.1 to approximately 2.5 atm. There is a marked difference in every case in comparison with the corresponding fractions (Psub(M),Psub(D)) measured in condensed media, with approximately 80 percent of incident muons forming muonium in the vapor phase compared to approximately 20 percent in the corresponding condensed phases. CClsub(4) appears somewhat anomalous in that it shows an unusually small muonium fraction in the vapor (fsub(D) approximately fsub(M)=0.5) and an unusually large diamagnetic fraction in the liquid (Psub(D)=1.0); these results can be attributed to large hot atom cross sections extending to the thermal regime, manifest as a relatively fast thermal rate constant for Mu + CClsub(4) (ksub(MU)=(2.9+-0.8) x 10sup(8) Msup(-1) ssup(-1)). The vapor phase results can be understood in terms of a charge exchange/hot atom (ion) model, providing also a likely explanation for observed pressure dependent fsub(D)'s in hexane, c-hexane and TMS at low (

1983-01-01

248

A method of gastric conduit elevation via the posterior mediastinal pathway in thoracoscopic subtotal esophagectomy  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Despite efforts to improve surgical techniques, serious complications still sometimes occur. Use of a physiological posterior mediastinal pathway has increased given advances such as automated anastomotic devices and a reduction in the incidence of anastomotic sufficiency. Until now the gastric conduit created has been protected by an echo probe cover and, sown to the ventral side of polyester tape placed through the abdomen to the neck, and then blindly elevated to the neck. We report on a new method of gastric conduit elevation. Methods Two 60-cm lengths polyester tape are ligated at both ends to form a loop. An echo probe cover of 10 cm in diameter and 50 cm in length is prepared and the tip cut off, forming a cylinder. The knots in the previously looped polyester tape are inserted into the echo probe cover. The looped polyester tape and echo probe cover is ligated with silk approximately 5 cm in front of the knots on both sides. After dissection is carried out according to practice, the previously crafted polyester tape is inserted into the chest cavity. One end of polyester tape is fixed to the distal esophageal stump with the clips, with the opposite end fixed to the proximal esophageal stump. The echo probe cover that connects the proximal esophagus and distal esophagus is monitored for the presence of creases along the long axis to ensure there are no twists in the echo probe cover. We carry out a laparoscopic-assisted perigastric lymph node dissection, make a small skin incision, and guide part of the thoracic esophagus and stomach outside the body. Either one of the two lengths of polyester tape is connected to the gastric conduit. By pulling up this length of polyester tape from the neck, the gastric conduit can pass through the echo probe cover and be elevated to the neck. Results No perioperative complications such as bleeding or difficulty of the gastric conduit elevation were recognized with this method. Conclusions This method is considered to serve as a useful technique for gastric conduit elevation.

Hirahara Noriyuki; Yamamoto Tetsu; Tanaka Tsuneo

2012-01-01

249

A numerical code of explosive conduit flows constrained by large-scale experiments  

Science.gov (United States)

Conduit exit conditions during explosive eruptions play a major role in determining the rate and style of the eruptive column. The main parameter characterizing the eruptive mixture at conduit exit is mass eruption rate (MER), which is the product of velocity, density and conduit section area. This was perceived by the first researchers, who constructed theoretical model on the dynamics of explosive eruptions (Wilson et al., 1980; Woods, 1988; Bursik and Woods, 1991). Numerical modelling also helped scientists in the understanding of the complex dynamics of this kind of eruptions (Macedonio et al., 2005; Neri et al., 1998; Papale, 2001; Papale et al., 1998). Finally, the first large scale experiments on the mechanics of eruptive columns and pyroclastic flows (Dellino et al., 2007) allowed the development of an empirical model for the prediction of exit velocity of eruptive mixtures and the conditions of existence of the main eruptive styles (Dellino et al., 2009). Since the experiments were successfully scaled to real eruptions, we implemented a numerical model that reproduces the main quantities measured in the experiments, with the aim of eventually extending the model to the natural case. This would be the first time that a numerical model on the mechanics of explosive eruptions is validated against large-scale experiments. A steady 1-D two phase numerical model of the conduit flow is presented here. In this model the equations of conservation of mass and momentum for gas and volcanic particles are solved via a Runge-Kutta method with an adaptive stepsize. The numerical model is implemented in a code written in Fortran 77 language. The use of an adaptive stepsize control over the Runge-Kutta method allows the achievement of a predetermined accuracy (in this case of the order of 10-5) with minimum computational effort. All the conditions of the experimental runs are implemented and the velocity field is initialized using the empirical model for mixture velocity (Dellino et al., 2009). The model takes in account the real shape of volcanic ash and uses the well established law of Dellino et al. (2005) for the calculation of particles' terminal velocity. The pressure gradient in the conduit, which represents the main driving force of the vertical two-phase flow, is obtained by the same empirical model (Dellino et al., 2009). Finally the interphase drag force and the friction between the phases and the conduit wall are included: the classic empirical laws for wall-particles and wall-fluid frictions developed in industrial engineering and classic fluid dynamics are implemented in the code. All the experimental runs have been simulated with the numerical code, and the model results in velocities that are quite consistent with experiments.

Dioguardi, Fabio; de Lorenzo, Salvatore; Dellino, Pierfrancesco

2010-05-01

250

Downsized Contegra Graft as a Right Ventricle-to-Pulmonary Artery Conduit in the Setting of Mediastinitis.  

Science.gov (United States)

Polytetrafluoroethylene (PTFE) grafts are commonly used for construction of the right ventricle-to-pulmonary artery conduit in the modified Norwood procedure. Dehiscence of a PTFE conduit in the setting of purulent mediastinitis presents a challenging clinical problem because of limited availability of appropriately sized replacement vascular homografts. The Contegra bovine jugular vein graft is an alternative to placing another PTFE graft in an infected space when a homograft of appropriate size is not available. We describe the use of a downsized Contegra conduit to replace an infected PTFE right ventricle-to-pulmonary artery graft in a neonate with life-threatening purulent mediastinitis. PMID:23992706

Maciver, Robroy H; Permut, Lester C; McMullan, David M

2013-09-01

251

Downsized Contegra Graft as a Right Ventricle-to-Pulmonary Artery Conduit in the Setting of Mediastinitis.  

UK PubMed Central (United Kingdom)

Polytetrafluoroethylene (PTFE) grafts are commonly used for construction of the right ventricle-to-pulmonary artery conduit in the modified Norwood procedure. Dehiscence of a PTFE conduit in the setting of purulent mediastinitis presents a challenging clinical problem because of limited availability of appropriately sized replacement vascular homografts. The Contegra bovine jugular vein graft is an alternative to placing another PTFE graft in an infected space when a homograft of appropriate size is not available. We describe the use of a downsized Contegra conduit to replace an infected PTFE right ventricle-to-pulmonary artery graft in a neonate with life-threatening purulent mediastinitis.

Maciver RH; Permut LC; McMullan DM

2013-09-01

252

Extracardiac Fontan with T-shape conduit in non-confluent pulmonary arteries  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract A 34 months-old male patient with double inlet right ventricle with nonconfluent pulmonary arteries who underwent successful extracardiac fenestarated Fontan procedure using pre-designed T-shaped PTFE vascular graft after multi-step rehabilitation of the diminutive hilar pulmonary arteries. At first we performed 6 mm confluent pulmonary artery vascular graft implantation with 4 mm BT shunt at patient's 4 weeks old. At 9 months of patient, we upsized the confluent pulmonary arterial graft to 8 mm with bidirectional cavopulmonary connection, and, at 34 months, we performed extracardiac conduit Fontan procedure with pre-designed T-shape conduit including the confluent pulmonary arterial portion at last. Patient shows excellent functional status and development.

Kwak Jae; Lee Jeong; Jang Woo-Sung; Bae Eun

2008-01-01

253

Investigating thermal hydraulic quenchback in a cable-in-conduit superconductor  

Energy Technology Data Exchange (ETDEWEB)

Quench propagation of a cable-in-conduit force-cooled superconductor plays a very important role in the protection of a magnet built with such a conductor as in a Superconducting Magnetic Energy Storage (SMES) system. Some thermal analysis showed that the compressional and frictional heating exerted by the expanding hot helium could heat the helium away from the normal zone above the superconductor current sharing temperature. Thus an acceleration of the quench propagation could be realized. This phenomenon was termed thermal hydraulic quenchback (THQ). A setup has been built specifically to investigate this phenomenon. The test sample consists of a 50-m-long NbTi superconducting cable enclosed in a stainless steel conduit. Heaters 0.2 to 8 m long are provided to quench the conductor. This paper reports experimental finding of THQ and its dependence on the initial normal zone length, the conductor current, and the temperature.

Lue, J.W.; Dresner, L.; Schwenterly, S.W.; Wilson, C.T.; Lubell, M.S.

1992-11-01

254

Investigating thermal hydraulic quenchback in a cable-in-conduit superconductor  

Energy Technology Data Exchange (ETDEWEB)

Quench propagation of a cable-in-conduit force-cooled superconductor plays a very important role in the protection of a magnet built with such a conductor as in a Superconducting Magnetic Energy Storage (SMES) system. Some thermal analysis showed that the compressional and frictional heating exerted by the expanding hot helium could heat the helium away from the normal zone above the superconductor current sharing temperature. Thus an acceleration of the quench propagation could be realized. This phenomenon was termed thermal hydraulic quenchback (THQ). A setup has been built specifically to investigate this phenomenon. The test sample consists of a 50-m-long NbTi superconducting cable enclosed in a stainless steel conduit. Heaters 0.2 to 8 m long are provided to quench the conductor. This paper reports experimental finding of THQ and its dependence on the initial normal zone length, the conductor current, and the temperature.

Lue, J.W.; Dresner, L.; Schwenterly, S.W.; Wilson, C.T.; Lubell, M.S.

1992-01-01

255

Using MODFLOW with CFP to understand conduit-matrix exchange in a karst aquifer during flooding  

Science.gov (United States)

Karst springs may reverse flow when allogenic runoff increases river stage faster than groundwater heads and may exchange of surface water with groundwater in the surrounding aquifer matrix. Recharged flood water is rich in nutrients, metals, and organic matter and is undersaturated with respect to calcite. Understanding the physical processes controlling this exchange of water is critical to understanding metal cycling, redox chemistry and dissolution in the subsurface. Ultimately the magnitude of conduit-matrix exchange should be governed by head gradients between the conduit and the aquifer which are affected by the hydraulic conductivity of the matrix, conduit properties and antecedent groundwater heads. These parameters are interrelated and it is unknown which ones exert the greatest control over the magnitude of exchange. This study uses MODFLOW-2005 coupled with the Conduit Flow Processes (CFP) package to determine how physical properties of conduits and aquifers influence the magnitude of surface water-groundwater exchange. We use hydraulic data collected during spring reversals in a mapped underwater cave that sources Madison Blue Spring in north-central Florida to explore which factors are most important in governing exchange. The simulation focused on a major flood in 2009, when river stage increased by about 10 meters over 9 days. In a series of simulations, we varied hydraulic conductivity, conduit diameter, roughness height and tortuosity in addition to antecedent groundwater heads to estimate the relative effects of each parameter on the magnitude of conduit-matrix exchange. Each parameter was varied across plausible ranges for karst aquifers. Antecedent groundwater heads were varied using well data recorded through wet and dry seasons throughout the spring shed. We found hydraulic conductivity was the most important factor governing exchange. The volume of exchange increased by about 61% from the lowest value (1.8x10-6 m/d) to the highest value (6 m/d) of matrix hydraulic conductivity. Other factors increased the amount of exchange by 1% or less, with tortuosity (which varied from 1 to 2) being most significant with a 1% increase, followed by conduit diameter (1 to 5 m) and roughness height (0.1 to 5m) with increases in exchange of 0.4% and 0.3% respectively. Antecedent aquifer conditions were also seen to exert important controls on influencing exchange with greater exchange occurring in floods following dry periods than during wet periods. These preliminary results indicate that heterogeneity of the hydraulic conductivity across karst aquifers will control the distribution of flood waters that enter into the aquifer matrix. Because flood waters are typically undersaturated with respect to the carbonate minerals, the location of this infiltrated water into the highest hydraulic conductivity zones should enhance dissolution, thereby increasing hydraulic conductivity in a feedback loop that will enhance future infiltration of floodwater. Portions of the aquifer prone to infiltrating flood water and dissolution will also be most sensitive to contamination from surface water infiltration.

Spellman, P.; Screaton, E.; Martin, J. B.; Gulley, J.; Brown, A.

2011-12-01

256

Support and positioning conduit for measuring instruments in a nuclear reactor core  

International Nuclear Information System (INIS)

[en] The external tubular casing of the measure conduit has many tubular sections machined to receive probes. These tubular sections are connected by flexible sections. An open final flexible section with apertures in its lateral wall put the casing in equipression with the primary water[fr] L'enveloppe tubulaire externe du conduit de mesure comporte une pluralite d'entretoises usinees interieurement chacune pour recevoir un ensemble de dispositifs de mesure. Les entretoises sont reliees par des troncons successifs de tube souple. L'enveloppe externe est ouverte a sa partie d'extremite debouchant dans le coeur du reacteur et comporte des ouvertures dans sa paroi laterale. Cette enveloppe est ainsi mise en equipression et les dispositifs de mesure sont en contact direct avec le fluide de refroidissement du reacteur

1986-11-26

257

Pipe for building thermally insulated conduits, and process for said building  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to an improved pipe, which allows submarine conduits such as oil and gas pipelines to be obtained free from discontinuities, and with a higher degree of thermal insulation, without varying the costs and building times relative to a conventional conduit. Such a pipe comprises a first section consisting of 2 concentrically disposed pipes, and second and third sections each consisting of a Y-shaped joint member. The diameter of the outer wall of the pipe reduces as it extends away from the bifurcated end of the Y, forming a frustoconical shaped ring, until the inner and outer walls join adjacent to the single end of the Y. The said single end defines a single cylindrical wall which has the same diameter as the inner wall of the pipe. When two sections of pipe are joined, a V-shaped cavity is thereby formed on the exterior of the pipe, which is then filled with thermally insulating material. 2 figs.

Berti, A.; Bruschi, R.; Raffaeli, E.; Gambelli, L.

1989-07-04

258

Stenting an aorto-pulmonary conduit with peripheral cardiopulmonary bypass support.  

UK PubMed Central (United Kingdom)

Although surgically-created aortopulmonary (AP) shunts are uncommon in the adult congenital heart disease population, they are often used in patients with pulmonary atresia. For these patients the shunt is a vital supply of pulmonary blood flow and thus obstruction of the shunt may lead to pulmonary hypoperfusion and hypoxia thereby increasing morbidity and mortality. This report describes a safe and effective method of stenting the conduit with the hemodynamic support of peripheral cardiopulmonary bypass (PCB). Prior to the procedure, a multi-modality assessment of a stenosis in a kinked AP conduit using computed tomography, angiography, intravascular ultrasound (IVUS) and pressure wire assessment (PWA) was utilized. While PCB, IVUS and PWA have all been used to great effect in various clinical scenarios, the combined use of these techniques has not been previously been described in the setting of intervention in adult congenital heart disease. © 2013 Wiley Periodicals, Inc.

Lee J; Incani A; Nicolae M; Walters D

2013-04-01

259

Design criteria for stability in cable-in-conduit conductors  

Energy Technology Data Exchange (ETDEWEB)

Stability is a key point in the design of large conductors for application in fusion machines such as NETY or ITER. In the electromagnetically noisy environment characterizing the surroundings of a plasma, the superconductor should be stable against all expected heat deposition, including a.c. losses driven by plasma disruptions. Since all sources of thermal perturbations cannot be adequately identified, predicted or calculated, the design must allow for suitable margins. To ensure this, stability must be considered as a design criterion which is checked by means of analytical and numerical methods and later calibrated against experimental measurements of transient heat transfer and stability behaviour. In this paper the procedure developed at NET is described for the design and analysis of the stability margin of conductors for the toroidal and poloidal field coils. These methods are applied to the generation of stability curves and maps which are used to set operating limits for the 40 kA NET conductor. The design criteria and analytical methods can be appropriately modified for other conductors and coil applications. (author).

Bottura, L.; Mitchell, N. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)); Minervini, J.V. (Los Alamos National Lab., NM (United States))

1991-07-01

260

Acceleration of autologous in vivo recellularization of decellularized aortic conduits by fibronectin surface coating.  

Science.gov (United States)

Decellularization is a promising option to diminish immune and inflammatory response against donor grafts. In order to accelerate the autologous in vivo recellularization of aortic conduits for an enhanced biocompatibility, we tested fibronectin surface coating in a standardized rat implantation model. Detergent-decellularized rat aortic conduits (n = 36) were surface-coated with covalently Alexa488-labeled fibronectin (50 ?g/ml, 24 h) and implanted into the systemic circulation of Wistar rats for up to 8 weeks (group FN; n = 18). Uncoated implants served as controls (group C; n = 18). Fibronectin-bound fluorescence on both surfaces of the aortic conduits was persistent for at least 8 weeks. Cellular repopulation was examined by histology and immunofluorescence (n = 24). Luminal endothelialization was significantly accelerated in group FN (p = 0.006 after 8 weeks), however, local myofibroblast hyperplasia with significantly increased ratio of intima-to-media thickness occurred (p = 0.0002 after 8 weeks). Originating from the adventitial surface, alpha-smooth muscle actin and desmin positive cell invasion into the media of fibronectin-coated conduits was significantly increased as compared to group C (p < 0.0001). In these medial areas, in situ zymography revealed enhanced matrix metalloproteinase activity. In both groups, inflammatory cell markers (CD3 and CD68) and signs of thrombosis proved negative. With regard to several markers of cell adhesion, inflammation and calcification, quantitative real-time PCR (n = 12) revealed no significant inter-group differences. Fibronectin surface coating of decellularized cardiovascular implants proved feasible and persistent for at least 8 weeks in the systemic circulation. Biofunctional protein coating accelerated the autologous in vivo endothelialization and induced a significantly increased medial recellularization. Therefore, this strategy may contribute to the improvement of current clinically applied bioprostheses. PMID:23683757

Assmann, Alexander; Delfs, Christofer; Munakata, Hiroshi; Schiffer, Franziska; Horstkötter, Kim; Huynh, Khon; Barth, Mareike; Stoldt, Volker R; Kamiya, Hiroyuki; Boeken, Udo; Lichtenberg, Artur; Akhyari, Payam

2013-05-15

 
 
 
 
261

Acceleration of autologous in vivo recellularization of decellularized aortic conduits by fibronectin surface coating.  

UK PubMed Central (United Kingdom)

Decellularization is a promising option to diminish immune and inflammatory response against donor grafts. In order to accelerate the autologous in vivo recellularization of aortic conduits for an enhanced biocompatibility, we tested fibronectin surface coating in a standardized rat implantation model. Detergent-decellularized rat aortic conduits (n = 36) were surface-coated with covalently Alexa488-labeled fibronectin (50 ?g/ml, 24 h) and implanted into the systemic circulation of Wistar rats for up to 8 weeks (group FN; n = 18). Uncoated implants served as controls (group C; n = 18). Fibronectin-bound fluorescence on both surfaces of the aortic conduits was persistent for at least 8 weeks. Cellular repopulation was examined by histology and immunofluorescence (n = 24). Luminal endothelialization was significantly accelerated in group FN (p = 0.006 after 8 weeks), however, local myofibroblast hyperplasia with significantly increased ratio of intima-to-media thickness occurred (p = 0.0002 after 8 weeks). Originating from the adventitial surface, alpha-smooth muscle actin and desmin positive cell invasion into the media of fibronectin-coated conduits was significantly increased as compared to group C (p < 0.0001). In these medial areas, in situ zymography revealed enhanced matrix metalloproteinase activity. In both groups, inflammatory cell markers (CD3 and CD68) and signs of thrombosis proved negative. With regard to several markers of cell adhesion, inflammation and calcification, quantitative real-time PCR (n = 12) revealed no significant inter-group differences. Fibronectin surface coating of decellularized cardiovascular implants proved feasible and persistent for at least 8 weeks in the systemic circulation. Biofunctional protein coating accelerated the autologous in vivo endothelialization and induced a significantly increased medial recellularization. Therefore, this strategy may contribute to the improvement of current clinically applied bioprostheses.

Assmann A; Delfs C; Munakata H; Schiffer F; Horstkötter K; Huynh K; Barth M; Stoldt VR; Kamiya H; Boeken U; Lichtenberg A; Akhyari P

2013-08-01

262

Evaluation of PRGD/FK506/NGF conduits for peripheral nerve regeneration in rats  

Directory of Open Access Journals (Sweden)

Full Text Available Context : Both tacrolimus (FK506) and nerve growth factor (NGF) enhance peripheral nerve regeneration, and in vitro experimental results demonstrate that the combination of FK506 and NGF increased neurite outgrowth compared with either treatment alone. Aim : To determine if the combination of FK506 and NGF benefits peripheral nerve regeneration compared with either treatment alone in vivo. Settings and Design : Rat sciatic nerves were cut off to form a 10 mm defect and repaired with the nerve conduits. All of the 32 Wistar rats were randomly divided into 4 groups: Group A: RGD peptide modification of poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PRGD)/FK506/NGF; Group B: PRGD/FK506; Group C: PRGD/NGF; and Group D: autologous nerves. Materials and Methods : At 3 months after surgery, the regenerated rat sciatic nerve was evaluated by electrophysiology, calf triceps wet weight recovery rate, and histologic assessment. Statistical Analysis Used : The SPSS 10.0 software (Bizinsight, Beijing China) was used for statistical analysis. Results : The compound muscle action potentials (CMAPs) of groups A and D were significantly stronger than those of groups B and C. The calf triceps wet weight recovery rate of groups A and D were higher than those of groups B and C. The regenerated nerves of groups A and D were more mature than those of groups B and C. There was no significant difference between groups A and D. Conclusions : PRGD/FK506/NGF sustained-release nerve conduits are more effective in regenerating nerves than both PRGD/FK506 sustained-release nerve conduits and PRGD/NGF sustained-release nerve conduits. The effect is as good as that of an autograft.

Jifeng Huang; Dezhong Li; Qiongjiao Yan; Huayong Zheng; Shipu Li

2010-01-01

263

AC losses for the prototype cable-in-conduit conductors for NET  

Energy Technology Data Exchange (ETDEWEB)

In this paper the AC losses requirement for the superconducting coils of the Next European Torus (NET) project are discussed on the basis of the pulsed field scenario and plasma disruptions. The AC losses test results on the prototype 40 kA cable-in-conduit superconductors developed for NET are presented: the performance achieved is compared with the target. Some recommendations are made for work to be done.

Bruzzone, P.; Bottura, L. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)); Eikelboom, J. (ECN Petten, P.B.1, NL-1755 ZG Petten (NL)); Roovers, A.J.M. (Technische Hogeschool Twente, Enschede (Netherlands))

1992-01-01

264

Modelling of dual stability in a cable-in-conduit conductor  

Energy Technology Data Exchange (ETDEWEB)

This paper reports on a zero dimensional stability model developed for cable-in-conduit superconductors. The model is effective in simulating the multi-valued stability behavior in the vicinity of the limiting current. This has been achieved by modifying the helium heat transfer coefficient to account for inertial and frictional terms which affect the induced helium flow. The model can reproduce with remarkable accuracy the multivalued stability behavior of previous measurements.

Bottura, L. (NET Team, Boltzmannst. 2, D-8046 Garching (DE)); Minervini, J.V. (Los Alamos National Lab., NM (United States))

1991-03-01

265

Ceramic fiber blanket wrap for fire protection of cable trays and conduits  

Energy Technology Data Exchange (ETDEWEB)

In some areas of nuclear power plants, cables of redundant electrical systems, which are necessary for the safe shutdown of the reactor, are in close proximity. If a fire should occur in one of these areas, both electrical systems could be destroyed before the fire is extinguished and control of the reactor may be lost. A ceramic fiber blanket was evaluated as a fire protective wrap around cable trays and conduits. 2 refs.

Chaille, C.E.; Reiman, R.J.

1980-01-01

266

Use of autogenous saphenous vein as a conduit for mesenterico-left portal vein bypass.  

UK PubMed Central (United Kingdom)

The authors describe a case of extrahepatic portal vein (EHPV) thrombosis and portal hypertension treated with a variant of mesenterico-left portal vein bypass (MLPVB) or Rex shunt. In this case, a segment of autogenous greater saphenous vein was used to bridge the distance between the left gastric vein inflow and the left portal vein. Use of such nontraditional conduit in similar circumstances may expand the application of portal revascularization/decompression procedures in treating these patients.

Query JA; Sandler AD; Sharp WJ

2007-06-01

267

Use of autogenous saphenous vein as a conduit for mesenterico-left portal vein bypass.  

Science.gov (United States)

The authors describe a case of extrahepatic portal vein (EHPV) thrombosis and portal hypertension treated with a variant of mesenterico-left portal vein bypass (MLPVB) or Rex shunt. In this case, a segment of autogenous greater saphenous vein was used to bridge the distance between the left gastric vein inflow and the left portal vein. Use of such nontraditional conduit in similar circumstances may expand the application of portal revascularization/decompression procedures in treating these patients. PMID:17560237

Query, Julie A; Sandler, Anthony D; Sharp, William J

2007-06-01

268

A 10-cm big stone formed in ileal conduit six years after cystectomy  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION: Ileal conduit (IC) is the standard urinary diversion following radical cystectomy. The formation of stone in the IC is one of the relatively common late complications of the procedure. CASE REPORT: The case of 69-year-old man who developed 10-cm large stone in the IC, six years after cystectomy is presented. CONCLUSION: The majority of patients with the stone in IC can be treated with minimally invasive techniques, like manual extraction, or endoscopic procedures.

Topuzovi? ?edomir; Pej?i? Tomislav; ?uraši? Ljubomir; Hadži-?oki? Jovan

2012-01-01

269

Copper vapor laser modular packaging assembly  

Energy Technology Data Exchange (ETDEWEB)

A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment.

Alger, Terry W. (Tracy, CA); Ault, Earl R. (Dublin, CA); Moses, Edward I. (Castro Valley, CA)

1992-01-01

270

The drag coefficient for particles in aerosols flowing through a horizontal conduit  

Directory of Open Access Journals (Sweden)

Full Text Available The drag coefficient, CD, was experimentally determined during sedimentation of aerosol particles in air flowing horizontally in a conduit of rectangular cross section, and its relation to the Reynolds numbers for the particle, Rep, and the conduit, Rec, was found. The method used to obtain the frictional force on the particles is based on observation of the trajectories of the particles being deposited on the bottom wall of the conduit. The diameter (dp) and point of deposition of the particles were determined by examining small glass slides distributed along the floor of the apparatus at given positions. The diameter of particles adhering to these laminae can be observed by microscope, but a factor must then be applied to convert these values to the diameters in suspension (dp), since the particles are liquid and undergo flattening as they collect on the glass. Results were compared with the aerodynamic diameter of the particle, obtained independently, and the discrepancies that appeared will need to be investigated further. The velocity profiles of the air inside the apparatus were also recorded. A correlation of the form CD = f(Rep, Rec) is proposed.

PEREIRA L.; MARRA JR W.D.; COURY J.R.

1999-01-01

271

Development of a 30-kA cable-in-conduit conductor for pulsed poloidal coils  

International Nuclear Information System (INIS)

[en] This paper describes design parameters of a 30-kA cable-in-conduit conductor (JF-30), and the test results of stability margin measured by using a triplex in a conduit. Cross sectional size of JF-30 is 35mm X 35 mm and 567 NbTi-Cu-CuNi strands are in a stainless steel conduit whose thickness is 2 mm. Void fraction is 33 % and the designed stability margin is 270 mJ/cc at 5 atm and 7 T. Stability test by a triplex showed a favorable margin, a few hundreds of mJ at 7 T even without helium flow. In addition, the stability was strongly increased when helium flow up to 0.2 g/s was applied. At around 3 atm, the authors found that the stability margin was more than 2 J/cc which exceeded the present heater capacity. This resulted in an extension of current range, in which the sample is stable, up to 150 to 200 % when compared to the case without helium flow

1983-01-01

272

Development of a 30-kA cable-in-conduit conductor for pulsed poloidal coils  

Energy Technology Data Exchange (ETDEWEB)

This paper describes design parameters of a 30-kA cable-in-conduit conductor (JF-30), and the test results of stability margin measured by using a triplex in a conduit. Cross sectional size of JF-30 is 35mm X 35 mm and 567 NbTi-Cu-CuNi strands are in a stainless steel conduit whose thickness is 2 mm. Void fraction is 33 % and the designed stability margin is 270 mJ/cc at 5 atm and 7 T. Stability test by a triplex showed a favorable margin, a few hundreds of mJ at 7 T even without helium flow. In addition, the stability was strongly increased when helium flow up to 0.2 g/s was applied. At around 3 atm, the authors found that the stability margin was more than 2 J/cc which exceeded the present heater capacity. This resulted in an extension of current range, in which the sample is stable, up to 150 to 200 % when compared to the case without helium flow.

Takashi, Y.; Dresner, L.; Kato, T.; Nishi, M.; Okuno, K.; Sanada, Y.; Tada, E.; Tsuji, H.

1983-05-01

273

Effects of streptozotocin-induced diabetes on the pharmacology of rat conduit and resistance intrapulmonary arteries  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Poor control of blood glucose in diabetes is known to promote vascular dysfunction and hypertension. Diabetes was recently shown to be linked to an increased prevalence of pulmonary hypertension. The aim of this study was to determine how the pharmacological reactivity of intrapulmonary arteries is altered in a rat model of diabetes. Methods Diabetes was induced in rats by the ?-cell toxin, streptozotocin (STZ, 60 mg/kg), and isolated conduit and resistance intrapulmonary arteries studied 3–4 months later. Isometric tension responses to the vasoconstrictors phenylephrine, serotonin and PGF2?, and the vasodilators carbachol and glyceryl trinitrate, were compared in STZ-treated rats and age-matched controls. Results STZ-induced diabetes significantly blunted the maximum response of conduit, but not resistance pulmonary arteries to phenylephrine and serotonin, without a change in pEC50. Agonist responses were differentially reduced, with serotonin (46% smaller) affected more than phenylephrine (32% smaller) and responses to PGF2? unaltered. Vasoconstriction caused by K+-induced depolarisation remained normal in diabetic rats. Endothelium-dependent dilation to carbachol and endothelium-independent dilation to glyceryl trinitrate were also unaffected. Conclusion The small resistance pulmonary arteries are relatively resistant to STZ-induced diabetes. The impaired constrictor responsiveness of conduit vessels was agonist dependent, suggesting possible loss of receptor expression or function. The observed effects cannot account for pulmonary hypertension in diabetes, rather the impaired reactivity to vasoconstrictors would counteract the development of pulmonary hypertensive disease.

Gurney Alison M; Howarth Frank C

2009-01-01

274

Safety of the Extended Radial Artery Conduit in Performing Complete Arterial Revascularization.  

UK PubMed Central (United Kingdom)

Purpose: We have developed a technique to elongate the radial artery (RA) with the distal segment of the left internal thoracic artery. This study investigated the safety and durability of this extended conduit compared with the composite Y-grafts.Methods: From January 1998 through December 2010, 750 patients underwent complete arterial revascularization with the use of the left internal thoracic artery (LITA) and RA. Out of these patients, 362 patients were operated on with the use of either RA-LITA extension conduit (n = 103), or a composite LITA-RA Y-graft (n = 259) and were included in this study. Cox regression analyses and Kaplan-Meyer survival curves were used to identify the predictive value of the RA-LITA extension technique on both survival and incidence of re-intervention.Results: Cox regression analysis showed that the use of RA-LITA extension conduit was not a significant predictor of re-intervention (p = 0.600) or total survival (p = 0.930).Kaplan-meier curves showed no significant difference between the two groups concerning total survival and re-intervention-free survival (p = 0.600).Conclusions: Our alternative technique of extending the RA with the distal segment of the LITA is a safe alternative for patients undergoing total arterial revascularization. The long-term survival and incidence of re-intervention is comparable with the composite LITA-RA Y-grafts.

Ozdemir HI; Soliman Hamad MA; Ter Woorst JF; Ozdemir MK; Berreklouw E; van Straten AM

2013-01-01

275

Bricker's ileal conduit urinary diversion with a simple non-refluxing uretero ileal anastomosis.  

DEFF Research Database (Denmark)

Fifty consecutive patients had ileal conduits constructed with a technically and quick simple antireflux ureteroileal anastomosis. Complications related to the ureteral implantation were studied retrospectively, and at follow-up (8 months-12 years later, median 3 years) conduit dysfunction and ureteral reflux were assessed in 18 patients out of the 25 patients who were still alive. Early complications and signs of late upper urinary tract deterioration were similar to those found after other operative techniques had been used. One patient had a postoperative urinary leak from the uretero ileal anastomosis. which was treated successfully by two weeks drainage. Hydronephrosis deteriorated in 18 (26%) of the renal units, remained unchanged in 39 (57%) and improved in 11 (16%). Increases in plasma creatinine concentrations up to 200 mumol/l were found in eight patients, and in one patient it increased from 300 to 420 mumol/l. Partial ureteral reflux was present in three (2 patients) of 33 ureters studied and minimal conduit dysfunction was found in 8 patients. In conclusion we find this method of urinary diversion to be quick, easy, and safe.

Bernstein, I T; Bennicke, K

1991-01-01

276

Large bifid ureteric calculus in a patient with an ileal conduit.  

UK PubMed Central (United Kingdom)

Urinary diversion after extirpative surgery of the bladder is done by various methods. Conduit urinary diversion is the most commonly practiced method of urinary diversion. It is relatively easy to perform and has a lower complication rate than other forms of diversion, e.g., orthotopic neobladder and continent cutaneous urinary diversion. Urolithiasis is a known and common complication of urinary diversion. Upper tract calculi in these cases often manifest symptomatically as occurs in the general population. Stones in the conduit can have a variable clinical presentation. Asymptomatic presentation is also noted in a few cases. We report a case of a large silent bifid ureteric calculus within an ileal conduit in a woman who had undergone urinary diversion 32 years earlier. Plain X-ray of the abdomen is the only investigation necessary to rule out urinary lithiasis in those who have had urinary diversion for a long time. This simple tool can diagnose the condition well in advance and aid in planning the management of this condition.

Rajaian S; Kekre NS

2012-09-01

277

Flambage vertical des conduites en souillées Vertical Buckling of Buried Pipes  

Directory of Open Access Journals (Sweden)

Full Text Available Si l'apparition d'un flambage vertical des conduites rigides enfouies dans une tranchée est un phénomène assez rare, il peut ne pas en être de même pour des conduites flexibles dont les propriétés mécaniques sont de nature différente. Une étude théorique et expérimentale, ayant pour but de proposer une méthode analytique de calcul de l'apparition du flambage et de son évolution sous l'effet de la pression interne, a été réalisée. II apparaît que les conduites flexibles actuelles sont très sensibles à ce phénomène et qu'il serait nécessaire, pour l'éliminer à coup sûr, de réexaminer la structure des flexibles ou d'imaginer des artifices dans la procédure d'ensouillage Whereas the appearance of vertical buckling in rigid pipes buried in a trench is a relatively rare phenomenon, the same cannot be said for flexible pipes which have mechanical properties of a different nature. A theoretical and experimental study has been made with the aim of proposing an analytical method for computing the appearance of buckling and its evolution under the effect of outside pressure. Current flexible pipes appear to be very sensitive to this phenomenon, and to be certain of eliminating it the structure of flexible pipes should be reexamined or stratagems in the burying procedure should be devised.

Bournazel C.

2006-01-01

278

The vapor pressures of explosives  

Energy Technology Data Exchange (ETDEWEB)

The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

2013-01-05

279

Vapor phase decarbonylation process  

UK PubMed Central (United Kingdom)

A process is provided for the synthesis of furan and related compounds by vapor-phase decarbonylation of furfural and derivatives, using a palladium/metal aluminate catalyst. The use of such catalysts, which are inherently less acidic than alumina, results in improved lifetime and high productivity. The compounds so produced can be used as starting materials for industrial chemicals for use as pharmaceuticals, herbicides, stabilizers, and polymers such as polyether ester elastomers and polyurethane elastomers.

OZER RONNIE

280

Two thermoformable spiral metallic ureteral stents in a patient with ileal conduit and distal stenosis of the ureters.  

UK PubMed Central (United Kingdom)

The insertion of two thermoformable ureteral titanium spiral stents (Memokath® 051) through ileal conduit due to bilateral ureteral stenosis distally has not been described in the English literature so far. We present the case of a young female patient with a history of ileal conduit urinary diversion due to congenital urinary bladder exstrophy, who had multiple previous surgeries and the insertion of two Memokath® ureteral stents in both ureters due to distal ureteral stenosis.

Al-Mahmid M; Ahrens U; Zimmer S; Winand S; Özgür E; Engelmann UH; Wille S

2013-01-01

 
 
 
 
281

Hydrocarbon vapor diffusion in intact core sleeves  

International Nuclear Information System (INIS)

The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the US Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact core sleeve sample was swept with nitrogen gas to simulate the diffusive release of hydrocarbon vapors from residual aviation gasoline in and immediately above the capillary fringe to a soil-venting air flow in the unsaturated zone. The resulting steady-state profile was modeled using existing diffusivity and air porosity estimates in a balance of diffusive flux and a first order source term. The source strength, which was calibrated with the observed flux of 2,2,4-TMP leaving the sleeve, varied with the residual gasoline remaining in the core, but was independent of the headspace sweep flow rate. This finding suggested that lower soil-venting air flow rates were in principle as effective as higher air flow rates in venting LNAPL vapors from contaminated soils. The saturated vapor concentration ratio of 2,2,4-TMP to 2,2,5-TMH decreased from 6.6 to 3.5 over the duration of the experiments in an expression of distillation effects. The vertical profile model was tested against sample port data in four separate experiments for both species, yielding mean errors ranging from 0 to -24% in magnitude.

1993-01-01

282

Covering sources of toxic vapors with foam  

International Nuclear Information System (INIS)

In a case of chemical terrorism, first responders might well be confronted with a liquid source of toxic vapor which keeps spreading out its hazardous contents. With foam as an efficient and simple means, such a source could be covered up in seconds and the spread of vapors mitigated drastically. Once covered, the source could then wait for a longer time to be removed carefully and professionally by a decontamination team. In order to find foams useful for covering up toxic vapor sources, a large set of measurements has been performed in order to answer the following questions: - Which foams could be used for this purpose? - How thick should the foam cover be? - For how long would such a foam cover be effective? - Could the practical application of foam cause a spread of the toxic chemical? The toxic vapors sources included GB, GD and HD. Among the foams were 10 fire fighter foams (e.g. AFFF, protein) and the aqueous decontamination foam CASCAD. Small scale experiments showed that CASCAD is best suited for covering a toxic source; a 10 cm layer of it covers and decontaminates GB. The large scale experiments confirmed that any fire fighter foam is a suitable cover for a longer or shorter period.(author).

2009-01-01

283

Injection locked oscillator system for pulsed metal vapor lasers  

Energy Technology Data Exchange (ETDEWEB)

An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)

1988-01-01

284

Linking conduit and surface activity at Arenal volcano using broadband seismometers and Doppler radar: do we need a new conduit model?  

Science.gov (United States)

We carried out a cross-correlation of broadband seismic data and ground-based Doppler radar data obtained at Arenal (Costa Rica) in February 2005. Our aim was to gain insight into the subsurface source processes (i.e., fragmentation mechanisms operating in the shallow conduit system) and the subsequent pyroclastic emissions (i.e., plume mass loading and ascent dynamics) that characterize the transitory, mildly explosive activity at Arenal. Study of the radar and seismic waveforms revealed a non-systematic relationship between them, both exhibiting a large variety of behaviors and features, but no clear patterns could be distinguished. Pyroclastic emissions recorded by the radar also did not have a unique seismic signature: 44% of radar signals were found in association with explosion-type seismic events, 43% during episodes of tremor, and 13% during aseismic intervals. Over longer time-scales, radar event amplitudes showed no correlation with the seismic energy release rate (RSEM), nor with RSAM, nor with repose time intervals. Energy proxies obtained from coeval radar (plume energy) and seismic (explosion energy) data show significant scattering, indicating that the ratio of the seismic/radar energy was highly variable. Plume mass-loading and exit velocity thus seems only weakly correlated to the seismic energy generated by the explosion, suggesting that the seismic energy might not be a good indicator of the intensity of explosions at Arenal. The occurrence of radar echoes in different range gates indicates that several vents were active, which is consistent with the clarinet-model for tremor generation at Arenal (Lesage et al., 2006), in which fractures in the plug act as valves that control degassing, with multiple conduits explaining the occurrence of different sets of harmonic frequencies in seismic data. Fragmentation is best explained by pressure build-up below a plug obstructing the conduit. This, when a resistance threshold is overcome, fails and yields sudden decompression, allowing gas bubbles in the magma to rapidly expand and fragment the viscous host magma. Nevertheless, this model fails to explain the full spectrum of activity, recorded signals, and seismo/radar energy partitioning. Variable source depth may, though, cause variation in elastic energy radiation, and variable fragmentation mechanisms may explain varying seismic signals associated with the emissions. It is possible that non-linear, inter- and time-dependent, processes explain unstable dynamic systems such as Arenal, and are required to trigger transitions from one fragmentation mechanism to another.

Valade, S.; Donnadieu, F. R.; Lesage, P.; Mora Fernandez, M.; Harris, A. J.; Alvarado, G. E.

2010-12-01

285

A metallic vapor laser  

Energy Technology Data Exchange (ETDEWEB)

The metallic vapor laser operating in a self heating condition contains a laser tube with electrodes, a resonator, and an excitation source connected to the tube electrodes, together with a master generator. In order to improve the pulsed lasing energy stability in measuring the pulse repetition rate of pulses over a wide range, the laser incorporates a pulsed heating source which generates pulses but which does not provide lasing, together with a controller whose output is connected to the master generator, and whose outputs are connected to the inputs to the excitation and heating sources; the output from the heating source is connected to the electrodes of the laser tube.

Voronov, V.I.; Fedorov, V.F.; Kirilov, A.Ye.; Soldatov, A.N.

1984-01-01

286

Delineating saturated conduit patterns and dimensions in the upper Floridan aquifer through numerical groundwater flow modeling (Invited)  

Science.gov (United States)

In groundwater flow modeling, aquifer permeability is typically defined through model calibration. Since the pattern and size of conduits are part of a karstic permeability framework, those parameters should be constrainable through the same process given a sufficient density of measured conditions. H2H Associates has completed a dual-permeability steady-state model of groundwater flow through the western Santa Fe River Basin, Florida from which a 380.9 km network of saturated conduits was delineated through model calibration to heads and spring discharges. Two calibration datasets were compiled describing average high-water and average low-water conditions based on heads at 145 wells and discharge from 18 springs for the high-water scenario and heads at 188 wells and discharge from 9 springs for the low-water scenario. An initial conduit network was defined by assigning paths along mapped conduits and inferring paths along potentiometric troughs between springs and swallets that had been connected by groundwater tracing. These initial conduit assignments accounted for only 13.75 and 34.1 km of the final conduit network respectively. The model was setup using FEFLOW™ where conduits were described as discrete features embedded in a porous matrix. Flow in the conduits was described by the Manning-Strickler equation where variables for conduit area and roughness were used to adjust the volume and velocity of spring flows. Matrix flow was described by Darcy’s law where hydraulic conductivity variations were limited to three geologically defined internally homogeneous zones that ranged from ~2E-6 m/s to ~4E-3 m/s. Recharge for both the high-water and low-water periods was determined through a water budget analysis where variations were restricted to nine zones defined by land-use. All remaining variations in observed head were then assumed to be due to conduits. The model was iteratively calibrated to the high-water and low-water datasets wherein the location, size and roughness of the conduits were assigned as needed to accurately simulate observed heads and spring discharges while bounding simulated velocities by the tracer test results. Conduit diameters were adjusted to support high-water spring discharges but the locations were best determined by calibration to the low-water head field. The final model calibrated to within 5% of the total head change across the model region at 143 of the 145 wells in the high-water scenario and at 176 of the 188 wells in the low-water scenario. Simulated spring discharges fell within 13% of the observed range under high-water conditions and to within 100% of the observed range under low-water conditions. Simulated velocities ranged from as low as 10-4 m/day in the matrix to as high as 10+3 m/day in the largest conduits. The significance of these results that we emphasize here is two-fold. First, plausible karstic groundwater flow conditions can be reasonably simulated if adequate efforts are made to include springs, swallets, caves, and traced flow paths. And second, detailed saturated conduit networks can be delineated from careful evaluation of hydraulic head data particularly when dense datasets can be constructed by correlating values obtained from different wells under similar hydraulic periods.

Kincaid, T. R.; Meyer, B. A.

2009-12-01

287

Reimplantation valve-sparing aortic root replacement in Marfan syndrome using the Valsalva conduit: an intercontinental multicenter study.  

UK PubMed Central (United Kingdom)

BACKGROUND: Introduced by DePaulis in 2000, the Gelweave Valsalva graft (Sulzer Vascutek, Refrewshire, Scotland) is a modified Dacron conduit (DuPont, Wilmington, DE), with prefashioned sinuses of Valsalva. The aim of this study was to evaluate the mid-term results of the reimplantation valve-sparing aortic root replacement using the Gelweave Valsalva prosthesis in Marfan syndrome patients. METHODS: A retrospective review was performed of 35 patients with Marfan syndrome in four centers who underwent the reimplantation valve-sparing aortic root replacement using the Gelweave Valsalva prosthesis. RESULTS: The patients were predominantly men, with a mean age of 36.5 +/- 12.6 years (range, 14 to 62 years). Two patients presented with acute type A dissections and underwent emergent operations. Elective hemiarch reconstruction using hypothermic circulatory arrest was required in 11 patients. Aortic valve cusp repair was performed in 2 patients. There were no operative or hospital deaths, and no patients died during follow-up. The mean follow-up was 19 months (range, 1 to 60 months). Significant (>2+) aortic insufficiency (AI), requiring aortic valve replacement, developed in 3 patients during follow-up that requiring aortic valve replacement. The 5-year freedom from reoperation owing to structural valve deterioration was 88.9% +/- 8.1%. There were no episodes of clinically significant thromboembolism. CONCLUSIONS: Reimplantation valve-sparing aortic root replacement with the Gelweave Valsalva prosthesis in Marfan patients provides satisfactory mid-term results, thus encouraging further use of this type of repair. However, long-term results are needed in order to define the durability of this technique.

Settepani F; Szeto WY; Pacini D; De Paulis R; Chiariello L; Di Bartolomeo R; Gallotti R; Bavaria JE

2007-02-01

288

Aortic conduit valve model with controlled moderate aortic regurgitation in rats.  

UK PubMed Central (United Kingdom)

Background:?The objective of this study was to describe a small animal aortic conduit model that could analyze long-term conduit valve (CV) function by echocardiography. Methods and Results:?Recipient Wistar rats (200-250g, n=20) underwent aortic leaflet injury of their native aortic valve under echocardiographic control. After 2 weeks, U-shaped decellularized CVs obtained from other rats were implanted onto the abdominal aorta. Implanted CVs were analyzed via pulsed-wave echocardiography at day 0, 4 and 12 weeks. CV stenosis was assessed as systolic flow velocity (post-pre CV)/flow velocity in the ascending aorta. CV regurgitation was assessed as the ratio of the amount of reversed diastolic flow to forward systolic flow in post-pre CV. The endpoint was set at 12 weeks. Three rats died immediately after aortic valve injury and all surviving rats received CV implantation (n=17, 85%). The survival rate after conduit implantation was 100% at 4 weeks and 88% (15/17) at 12 weeks. Regarding the CV function at 0, 4 and 12 weeks, the average observed value of CV stenosis was 3.8±7.9%, 3.1±4.1% and 14±10% (P<0.01), respectively. The average value of CV regurgitation was 0%, 12±27% and 52±43%, respectively (P<0.001). Conclusions:?By using this model, the degeneration of implanted CV could be assessed not only qualitatively, but also quantitatively.??(Circ J?2013; 77: 2295-2302).

Munakata H; Assmann A; Poudel-Bochmann B; Horstkötter K; Kamiya H; Okita Y; Lichtenberg A; Akhyari P

2013-08-01

289

Aortic conduit valve model with controlled moderate aortic regurgitation in rats.  

Science.gov (United States)

Background:?The objective of this study was to describe a small animal aortic conduit model that could analyze long-term conduit valve (CV) function by echocardiography. Methods and Results:?Recipient Wistar rats (200-250g, n=20) underwent aortic leaflet injury of their native aortic valve under echocardiographic control. After 2 weeks, U-shaped decellularized CVs obtained from other rats were implanted onto the abdominal aorta. Implanted CVs were analyzed via pulsed-wave echocardiography at day 0, 4 and 12 weeks. CV stenosis was assessed as systolic flow velocity (post-pre CV)/flow velocity in the ascending aorta. CV regurgitation was assessed as the ratio of the amount of reversed diastolic flow to forward systolic flow in post-pre CV. The endpoint was set at 12 weeks. Three rats died immediately after aortic valve injury and all surviving rats received CV implantation (n=17, 85%). The survival rate after conduit implantation was 100% at 4 weeks and 88% (15/17) at 12 weeks. Regarding the CV function at 0, 4 and 12 weeks, the average observed value of CV stenosis was 3.8±7.9%, 3.1±4.1% and 14±10% (P<0.01), respectively. The average value of CV regurgitation was 0%, 12±27% and 52±43%, respectively (P<0.001). Conclusions:?By using this model, the degeneration of implanted CV could be assessed not only qualitatively, but also quantitatively.??(Circ J?2013; 77: 2295-2302). PMID:23719661

Munakata, Hiroshi; Assmann, Alexander; Poudel-Bochmann, Bhawana; Horstkötter, Kim; Kamiya, Hiroyuki; Okita, Yutaka; Lichtenberg, Artur; Akhyari, Payam

2013-05-29

290

Minimally invasive esophagectomy with extracorporeal gastric conduit creation--how I do it.  

UK PubMed Central (United Kingdom)

Esophagectomy is associated with significant morbidity and mortality rates. In an attempt to improve these results, many groups have started applying minimally invasive techniques to esophagectomy for benign and malignant disease. A variety of minimally invasive approaches have been developed. At the Thomas Jefferson University, we have offered minimally invasive three-hole esophagectomy with extracorporeal gastric conduit creation since 2008. Herein we report our technique for the abdominal and cervical components of the procedure and briefly discuss the current literature and our short-term perioperative outcomes.

Palazzo F; Evans NR 3rd; Rosato EL

2013-09-01

291

Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm  

Science.gov (United States)

Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

Moore, Karen A. (Idaho Falls, ID); Zatorski, Raymond A. (East Hampton, CT)

2007-10-02

292

Recurrent cervical esophageal stenosis after colon conduit failure: use of myocutaneous flap.  

UK PubMed Central (United Kingdom)

A 53-year-old male developed cervical esophageal stenosis after esophageal bypass surgery using a right colon conduit. The esophageal bypass surgery was performed to treat multiple esophageal strictures resulting from corrosive ingestion three years prior to presentation. Although the patient underwent several endoscopic stricture dilatations after surgery, he continued to suffer from recurrent esophageal stenosis. We planned cervical patch esophagoplasty with a pedicled skin flap of sternocleidomastoid (SCM) muscle. Postoperative recovery was successful, and the patient could eat a solid meal without difficulty and has been well for 18 mo. SCM flap esophagoplasty is an easier and safer method of managing complicated and recurrent cervical esophageal strictures than other operations.

Sa YJ; Kim YD; Kim CK; Park JK; Moon SW

2013-01-01

293

Biosorption of copper by a bacterial biofilm on a flexible polyvinyl chloride conduit.  

UK PubMed Central (United Kingdom)

Inexpensive technologies with less-than-optimal efficiencies as a strategy for countering economic restraints to pollution control have been evaluated by using a laboratory-scale biotreatment process for copper-containing effluent. Economizing measures include the use of polyvinyl chloride (PVC) cylinders fashioned from commercially available flexible PVC conduit to support a biofilm that was cultured in an inexpensive medium prepared in wastewater. The biofilm was challenged by aqueous copper solution in a bioreactor and subsequently analyzed under a scanning electron microscope with energy-dispersive X-ray microanalysis.

Qureshi FM; Badar U; Ahmed N

2001-09-01

294

Parametric study of the stability margins of cable-in-conduit superconductors: experiment  

International Nuclear Information System (INIS)

In a previous experiment on the stability of cable-in-conduit superconductors, we sometimes observed multivalued stability margins, which we attributed to strong heating-induced transient flows. We proposed a schematic theory from which we derived a scaling relation for the limiting current below which the stability margin is always singlevalued. Measurements at different magnetic fields are used to test the scaling with critical temperature and resistivity. We also examine the scaling with heated length and heat pulse duration. The results of these experiments are given and compared with theory

1980-10-02

295

Melt and vapor characteristics in an electron beam evaporator  

Energy Technology Data Exchange (ETDEWEB)

We compare the free surface temperatures T{sub s}, calculated by two methods, in cerium or copper evaporation experiments. The first method considers properties of the melt: by an empirical law we take into account turbulent thermal convection, instabilities and craterization of the free surface. The second method considers the vapor flow expansion and connects T{sub s} to the measured terminal parallel temperature and the terminal mean parallel velocity of the vapor jet, by Direct Simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high craterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that T{sub s} and the Knudsen number at the vapor source reach a threshold when the beam power increases.

Blumenfeld, L.; Fleche, J.L.; Gonella, C. [DCC/DPE/SPEA Centre d`Etudes de Saclay, Gif-sur-Yvette (France)

1994-12-31

296

Longitudinal growth of the autologous vessels above and below the Gore-Tex graft after the extracardiac conduit Fontan procedure.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Reflecting excellent mid-term outcomes, extracardiac conduit Fontan procedure (ECFP) using Gore-Tex tube graft has been performed with increasing frequency in patients with functional single ventricle. Nevertheless, due to the lack of growth potential of the artificial conduit, the status of the venous pathway along with somatic growth is a continuing concern. In this study, we evaluated the longitudinal growth of the autologous vessels above and below the Gore-Tex graft used in the ECFP. METHODS: This study included 34 patients who had completed cardiac catheterisations at 1 month and 5.1 years after the ECFP. The average age, weight and height at the ECFP were 3.8+/-2.5 years (1.8-12.7 years), 12.7+/-4.6 kg (7.4-33.0 kg) and 92.9+/-16.1cm (72.5-153.5 cm), respectively. We measured the vertical lengths of three different parts angiographically: the length between the confluence point of the innominate vein and the anastomotic site of the conduit to the pulmonary artery (SVC-C), the conduit vertical length (C) and the length between the confluence point of the hepatic vein and the conduit's anastomotic site to the inferior vena cava (IVC-C). RESULTS: We have not observed stenosis or thrombus formation in the conduit or distortion of the conduit or pulmonary artery in any of the cases. No intervention or re-operation related to the extracardiac conduit was required, and laminar flow through the conduit was maintained with efficient Fontan haemodynamics. At 5.1 years after the ECFP, the average weight and height gain were 10.3+/-4.4 kg and 28.5+/-1.9 cm, respectively. The length of SVC-C, C and IVC-C were significantly increased as 124+/-15%, 106+/-7% and 132+/-24%, respectively, compared to the lengths at 1 month after the ECFP. The degree of increase in SVC-C and IVC-C was significantly larger than that in C. CONCLUSIONS: Along with the patient's somatic growth, longitudinal growth of the autologous vessels above and below the Gore-Tex graft was demonstrated to compensate for the lack of growth potential of the artificial graft.

Ochiai Y; Imoto Y; Sakamoto M; Sese A; Tsukuda M; Watanabe M; Ohno T; Joo K

2010-05-01

297

Total cavopulmonary connection in patients with apicocaval juxtaposition: optimal conduit route using preoperative angiogram and flow simulation.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Single ventricle with apicocaval juxtaposition (ACJ) is a rare, complex anomaly, in which the optimal position of the conduit for completion of total cavopulmonary connection (TCPC) is still controversial. The purpose of this study was to identify a preoperative method for optimal conduit position using the IVC anatomy and computational fluid dynamics (CFD). METHODS: Twenty-four patients with ACJ (5.3 ± 5.7 years) who underwent TCPC were enrolled. A conduit was placed ipsilateral to the cardiac apex in each of 11 patients, of which 9 were intra-atrial and 2 extracardiac (group A) and, in a further 13 patients, extracardiac on the contralateral side (group B). As control, 10 patients with tricuspid atresia were also enrolled (group C). The location of the IVC in relation to the spine was evaluated from the frontal view of preoperative angiogram, using the following index: IVC-index = IVC width overlapping the vertebra/width of the vertebra × 100%. Energy loss was calculated by CFD simulation. RESULTS: IVC-index of group B was larger than groups A and C (45 ± 26 vs. 20 ± 21 and 28 ± 19%, P = 0.03). Postoperative catheterizations showed that, due to its curvature, conduit length in group B was significantly longer than the others (65 ± 12 vs. 36 ± 14 and 44 ± 10 mm, P < 0.001), although there was no statistical difference in central venous pressure or cardiac output. CFD studies revealed less energy loss in group A conduits compared with group B (1.6 ± 0.3 vs. 3.6 ± 0.6 mW, P = 0.05), although this did not appear to be clinically significant. Moreover, CFD simulation showed significant energy loss within the Fontan circulation when the conduit was either compressed or kinked: 4.9 and 18.2 mW respectively. CONCLUSIONS: In patients with ACJ, placement of a straighter and shorter conduit on the ventricular apical side provides better laminar blood flow with less energy loss. However, conduit compression and kinking are far more detrimental to the Fontan circulation. A preoperative IVC-index is pivotal for avoiding these factors and deciding the optimal conduit route.

Yoshida M; Menon PG; Chrysostomou C; Pekkan K; Wearden PD; Oshima Y; Okita Y; Morell VO

2013-07-01

298

Replacement of valved right ventricular to pulmonary artery conduits: an observational study with focus on right ventricular geometry.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Timing of the operation for exchange of right ventricular (RV) to pulmonary artery (PA) conduits is a matter of considerable debate. We aimed to study the course of right ventricular dimension in patients undergoing conduit exchange. PATIENTS AND METHODS: We retrospectively studied all patients who underwent implantation and or replacement of RV/PA conduits during the time period between 1990 and 2005. Clinical and echocardiographic data were recorded as obtained at follow-up visits. RESULTS: A total of 229 (144 boys and 85 girls) underwent surgery for implantation and or replacement of RV/PA conduits during the study period. Patients were assigned to three age groups including 37 infants, 125 children aged 1-10 years and 67 patients more than 10 years of age. 185 pulmonary (81%) and 44 aortic homografts (19%) were implanted. Fifty-eight of these 185 patients (25%) required exchange of conduits after a median time of 6.4 (8 months-12 years) (median (range)). The follow-up was 7.55 (0.1-17) years. The survival of the patients after homograft change was 98%. Freedom from failure for aortic and pulmonary homografts at an interval of 10 years for all patients was 38.5% for aortic and 56.2% for pulmonary homografts (P = 0.018; Mann-Whitney). Age at conduit exchange (coefficient: -4.917; P < 0.001) and right ventricular end-diastolic dimension (RVDD) before conduit exchange (coefficient: 8.255; P < 0.001) were related to RVDD as measured by M-mode echocardiography at follow-up ("best subset" regression analysis; R squared = 0.746). RVDD decreased in 48/58 patients, remained unchanged in 8/58 and increased in 2/59 patients at follow-up. An increased RVDD was positively correlated to the duration of artificial ventilation after the operation for conduit exchange (R = 0.56; P < 0.001). CONCLUSIONS: Reoperation for exchange of degenerated conduits should be performed early to prevent the development of irreversible structural myocardial changes and persistence of right ventricular dilatation.

Loukanov T; Sebening C; Springer W; Khalil M; Ulmer HE; Hagl S; Karck M; Gorenflo M

2008-03-01

299

Valsalva graft in the Bentall procedure: from mechanical valve to the BioValsalva, world's first biological aortic conduit.  

Science.gov (United States)

Aortic root replacement is the procedure of choice for patients with ascending aortic aneurysms and diseased aortic valve leaflets. The increasing age of patients who undergo aortic root surgery, and data that support the use of a biological aortic valve in the younger population, have significantly increased the need for a composite biological valved conduit. The third-generation Triplextrade (Terumo Vascutek, Renfrewshire, Scotland, UK) Dacron conduit with its three-layer technology, can be stored in glutaraldehyde along with biological prostheses while maintaining a complete blood impermeability. As the result of this fundamental improvement, the ready-to-use composite biological valved graft is currently available for the first time in different sizes, which avoids the need of assembling it on the surgical table. The procedure is expedited and a better hemostasis achieved because of the intrinsic characteristics of the new three-layered conduit. The BioValsalva (Terumo Vascutek, Renfrewshire, Scotland, UK) has been obtained by suturing a stentless aortic valve (Elan, Kohler, Leeds, UK) inside a Triplex Valsalva graft and combining the advantages of a biological valved conduit with the advantages of better leaflets dynamics, less tension on coronary ostia, and improved coronary flow proper of the Valsalva conduit. The authors' preliminary clinical experience with the BioValsalva is reported herein and the technique is discussed. PMID:18802905

De Paulis, Ruggero; Scaffa, Raffaele; Maselli, Daniele; Weltert, Luca; Salica, Andrea; Bellisario, Alessandro

2008-01-01

300

Valsalva graft in the Bentall procedure: from mechanical valve to the BioValsalva, world's first biological aortic conduit.  

UK PubMed Central (United Kingdom)

Aortic root replacement is the procedure of choice for patients with ascending aortic aneurysms and diseased aortic valve leaflets. The increasing age of patients who undergo aortic root surgery, and data that support the use of a biological aortic valve in the younger population, have significantly increased the need for a composite biological valved conduit. The third-generation Triplextrade (Terumo Vascutek, Renfrewshire, Scotland, UK) Dacron conduit with its three-layer technology, can be stored in glutaraldehyde along with biological prostheses while maintaining a complete blood impermeability. As the result of this fundamental improvement, the ready-to-use composite biological valved graft is currently available for the first time in different sizes, which avoids the need of assembling it on the surgical table. The procedure is expedited and a better hemostasis achieved because of the intrinsic characteristics of the new three-layered conduit. The BioValsalva (Terumo Vascutek, Renfrewshire, Scotland, UK) has been obtained by suturing a stentless aortic valve (Elan, Kohler, Leeds, UK) inside a Triplex Valsalva graft and combining the advantages of a biological valved conduit with the advantages of better leaflets dynamics, less tension on coronary ostia, and improved coronary flow proper of the Valsalva conduit. The authors' preliminary clinical experience with the BioValsalva is reported herein and the technique is discussed.

De Paulis R; Scaffa R; Maselli D; Weltert L; Salica A; Bellisario A

2008-01-01

 
 
 
 
301

Quench propagation in a cable-in-conduit force-cooled superconductor---Preliminary results  

Energy Technology Data Exchange (ETDEWEB)

Cable-in-conduit force-cooled superconductor is being considered for use in a superconducting magnetic energy storage (SMES) system. The quench behavior of such a conductor plays a very important role in the protection of this system and of other magnets having similar cooling environments. In particular, the existence of the thermohydraulic quenchback effect predicted recently by numerical analysis and theoretical calculation has been investigated experimentally. The test sample consists of a 50-m-long single triplex NbTi superconductor enclosed in a stainless steel conduit. Heaters 0.2 to 8 m long are provided both at the center and one end of the sample, and the heated end can be closed off to stimulate quenching centered in a 100-m-long conductor. The quench behavior of the conductor (e.g., the propagation velocity and the temperature profile) was measured as a function of initial normal zone length, conductor current density, helium temperature, etc. This paper reports the test results and the comparison with the predictions.

Lue, J.W.; Schwenterly, S.W.; Dresner, L.; Lubell, M.S.

1990-01-01

302

[The possibilities of using a non-degradable materials as conduits in peripheral nerve reconstructions].  

UK PubMed Central (United Kingdom)

Rupture of the nerve is indication to perform reconstruction by direct neurorrhaphy or with autogenic nerve grafts. An alternative to using nerve grafts may be employ of an artificial conduits consisted of degradable or non-degradable polymers. In this study we presented the possibilities of using of non-degradable polymers in experimental studies and medical practice. The advantages of these materials were emphasized, but also limitations in its use were described. Directions in future progress and possibilities of enrichment nerve conduits by nerve regeneration facilitating factors such as: Schwann cells, mesenchymal stem cells, neurotrophic factors (NGF, GDNF, CNTF, VEGF, PDGF), extracellular matrix elements (collagen, laminin, fibronectin) and structural elements improving axon regeneration (filaments) were also described. In summary the properties of useful in medical practice neural tube were established. All indicate that future directions of experimental studies on using polymers in peripheral nerve reconstructions will be based on degradable materials. The role of non-degradable materials will be limited to using as control groups in experimental studies and in studies of following nerve regeneration improving factors.

Gosk J; Mazurek P; Reichert P; Wnukiewicz W; Rutowski R

2010-01-01

303

Choice of conduit for coronary artery bypass grafting in poor ventricles.  

UK PubMed Central (United Kingdom)

BACKGROUND: advantages in the use of arterial grafts for coronary artery revascularizations have been reported previously. OBJECTIVES: we aimed to compare the outcome and survival rates of different conduits in patients with poor ventricular function (ejection fraction<30%). METHODS: in a 10-year period, 979 patients with an ejection fraction<30%, who underwent isolated first-time coronary artery bypass grafting, were divided into in 3 groups: (A) total arterial grafts (n=257), (B) total vein grafts (n=76), and (C) left internal mammary artery and vein grafts (n=610). Multivariate logistic regression was used to assess the effect of graft type on mortality, while adjusting for patient and disease characteristics. Hospital mortality and 5-year survival rates were compared among the groups. RESULTS: hospital mortality was 8.9% for group A, 11.8% for group B, and 5.7% for group C. Mortality at 5 years was 27.2% for group A, 42.3% for group B, and 28.7% for group C. After risk adjustment, hospital mortality and mid- and long-term mortality showed no significant differences among the groups. CONCLUSIONS: patients with poor ventricular function have a high mortality rate in both the short- and long-term with any type of conduit. Mortality rates with total arterial grafts and vein plus arterial grafts were comparable before and after risk adjustment.

Attaran S; Shaw M; Saleh HZ; Pullan MD; Fabri BM

2012-08-01

304

Traitements de substitution et conduite automobile Opiate addiction treatment and driving  

Directory of Open Access Journals (Sweden)

Full Text Available Les médicaments de substitution (méthadone et buprénorphine), à l'instar d'autres médicaments psychotropes, possèdent des propriétés pharmacologiques susceptibles de perturber l'aptitude à la conduite automobile. Sur la base des données neurocomportementales, expérimentales et épidémiologiques disponibles, le risque de survenue d'accident de la voie publique dépend du stade du traitement et d'éventuelles associations avec d'autres psychotropes. La seule étude comparative retrouvée dans la littérature semble indiquer que la buprénorphine modifierait moins l'aptitude à la conduite automobile que la méthadone. Potential impairing effects on driving can be expected with the compounds used for opiate addiction treatment (methadone and buprenorphine), owing to their pharmacological properties, as with numerous other psychoactive drugs. The review of neurobehavioural, experimental and epidemiological data shows an increased risk of crash at the beginning of the treatment and in case of drug association. The sole comparative study found in the literature showed that buprenorphine induced less psychomotor impairment than methadone.

Gaulier Jean-Michel; Marquet Pierre; Lachatre Gérard

2009-01-01

305

Improvement of domain wall conduit properties in cobalt nanowires by global gallium irradiation  

Science.gov (United States)

Applications based on the movement of domain walls (DWs) in magnetic nanowires (NWs) require a good DW conduit behavior, i.e. a significant difference between DW nucleation and propagation fields. In this work, we have systematically studied how this property evolves in cobalt NWs grown by focused electron beam induced deposition (FEBID) as a function of global gallium irradiation, for irradiation doses up to 1.24 × 1017 ions cm?2. Whereas for high doses the DW conduit is lost, below 6.42 × 1015 ions cm?2 the difference between the two fields increases with irradiation, becoming up to ?9 times larger than for non-irradiated wires, due to a strong increase in the nucleation field, while the propagation field remains approximately constant. This behavior stems from two effects. The first effect is a decrease in the magnetic volume of the parasitic halo around the NW, typically present in FEBID nanostructures, leading to the disappearance of weak nucleation centers. The second effect is the formation of a 20 nm outer shell with Co crystals about twice the size of those forming the NW core, causing a net increase of the local magnetocrystalline anisotropy. The results presented here are important for the potential use of magnetic NWs grown by FEBID in DW-based devices, and might also be of interest for magnetic NWs fabricated by other techniques.

Serrano-Ramón, L.; Fernández-Pacheco, A.; Córdoba, R.; Magén, C.; Rodríguez, L. A.; Petit, D.; Cowburn, R. P.; Ibarra, M. R.; De Teresa, J. M.

2013-08-01

306

Post-esophagectomy gastric conduit cancers: treatment experiences and literature review.  

UK PubMed Central (United Kingdom)

Esophagectomy remains the mainstay of treatment for esophageal cancer. The stomach is the commonest organ used to restore intestinal continuity after esophagectomy. Metachronous gastric cancer in the gastric conduit after esophagectomy is rare; the etiology remains unclear. Possible risk factors include Helicobacter pylori infection, biliary or pancreatic reflux and prior radiotherapy. Prognosis of these patients remains poor. Treatment of this particular entity poses unique challenges to the surgeon and oncologist. Early diagnosis by endoscopy may allow endoscopic excision such as endoscopic mucosal resection or endoscopic submucosal dissection. In more advanced cancers, surgery is difficult, reconstruction is complicated, and further radiation may not be feasible because of previous neoadjuvant therapy. In this report, four patients who developed gastric conduit cancers are presented. They were treated with either surgery alone or combined with chemoradiotherapy. All four patients were still alive after at least 21 months, with three patients currently still alive (21-48 months). The literature is also reviewed, in particular addressing the incidence, possible underlying causes, prognosis and options of treatment for this specific clinical scenario.

Ho C; Tong DK; Tsang JS; Law SY

2013-04-01

307

Robotic Intracorporeal Ileal Conduit Formation: Initial Experience from a Single UK Centre  

Science.gov (United States)

Objectives. To describe our technique of robotic intracorporeal ileal conduit formation (RICIC) during robotic-assisted radical cystectomy (RARC). To report our initial results of this new procedure. Patients and Methods. Seven male and one female patients underwent RARC with RICIC over a six-month period. Demographic, operative, and outcome data was collected prospectively. Median patient age was 75 years (range 62–78 years). Median followup was 9 months (range 7–14 months). Results. RARC with RICIC was performed successfully in all eight patients. The median total operating time was 360 minutes (range 310–440 minutes) with a median blood loss of 225?mL (range 50–1000?mL). The median length of stay was nine days (range 6–34 days). Four patients (50%) were discharged within seven days. Four patients (50%) experienced one or more complications. This included two Clavien I complications, two Clavien II complications, and two Clavien III complications. Two patients (25%) required transfusion of two units each. To date, there have been no complications associated with the ileal conduit. Conclusion. Whilst being technically challenging, this procedure is safe, feasible, and reproducible. Patients who avoid complication show potential for rapid recovery and early discharge.

Bishop, Conrad V.; Adshead, James M.

2013-01-01

308

Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion  

Energy Technology Data Exchange (ETDEWEB)

Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux during the cooling process-from values typical for film boiling to much higher values typical for nucleate boiling. Correlations for the minimum temperature and the minimum heat flux necessary to maintain film boiling were established in terms of the subcooling level, the size of the spheres and their material. The minimum temperature to maintain film boiling was used as the principle criteria for the occurrence of vapor explosion. Other criteria, for the intensity of the vapor film collapse was derived from the maximum heat flux following the vapor film collapse, and the audible sound (which is generated by the shock wave). It is assumed that a high intensity of the vapor film collapse will result in a more efficient propagation stage and enhancement of the vapor explosion.

Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

2009-04-15

309

Nonlinear phenomena in fluids with temperature-dependent viscosity an hysteresis model for magma flow in conduits  

CERN Document Server

Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. As a consequence, this system may show an hysteresis effect, and the transition between the two branches can occur quickly when certain critical points are reached. In this paper we describe a model to study the relation between the pressure at the inlet and the volumetric magma flow rate in a conduit. We apply this model to explain an hysteric jump observed during the dome growth at Soufri\\`ere Hills volcano (Montserrat), and described by Melnik and Sparks [1999] using a different model.

Costa, A; Costa, Antonio; Macedonio, Giovanni

2002-01-01

310

Apicoaortic valved conduit bypass for progressing aortic graft stenosis due to malformation of repeated thoracic endovascular aortic repairs.  

UK PubMed Central (United Kingdom)

Since the first report by Cooley and colleagues in 1975 [Cooley DA, Norman JC, Mullins CE, Grace R. Left ventricle to abdominal aorta conduit for relief of aortic stenosis. Cardiovasc Dis 1975;2:376-83], an apicoaortic valved conduit bypass has been usually administrated to selected patients presenting with certain clinical conditions or complications such as aortic stenosis associated with porcelain aorta, unclampable atherosclerotic aorta, resternotomy, or previous coronary bypass surgery. On the other hand, thoracic endovascular aortic repair for various aortic lesions has become a promising and less invasive therapy. We encountered a critical case of a patient suffering from aortic graft stenosis due to malformation of a previous thoracic endovascular aortic repair procedure originally performed for acute type A aortic dissection. Because of a deep sternal wound infection, apicoaortic valved conduit bypass from the left ventricular apex to the abdominal aorta was successfully performed.

Iida Y; Koizumi N; Matsuyama K; Iwahashi T; Ogino H

2013-01-01

311

Behavioral evaluation of regenerated rat sciatic nerve by a nanofibrous PHBV conduit filled with Schwann cells as artificial nerve graft.  

UK PubMed Central (United Kingdom)

The aim of this study is to develop a nanofibrous polymeric nerve conduit with Schwann cells (SCs) and to evaluate its efficiency on the promotion of functional and locomotive activities in rats. The conduits were implanted into a 30-mm gap in the sciatic nerves of the rats. Four months after surgery, the rats were monitored and evaluated by behavioral analyses such as toe out angle, toe spreading analysis, walking track analysis, extensor postural thrust, open-field analysis, swimming test and nociceptive function, four months post surgery. Four months post-operatively, the results from behavioral analyses demonstrated that in the grafted groups especially in the grafted group with SCs, the rat sciatic nerve trunk had been reconstructed with functional recovery such as walking, swimming and recovery of nociceptive function. This study proves the feasibility of artificial conduit with SCs for nerve regeneration by bridging a longer defect in the rat model.

Biazar E; Heidari Keshel S; Pouya M

2013-09-01

312

Operação de Rastelli utilizando-se conduto valvulado de pericárdio bovino: experiência inicial Rastelli operation with bovine pericardium valved conduit: early experience  

Directory of Open Access Journals (Sweden)

Full Text Available O presente trabalho descreve a experiência inicial com a operação de Rastelli, utilizando-se um conduto valvulado de pericárdio bovino preservado em glutaraldeído. O enxerto consta de um conduto, que serve para reconstruir a via de saída do ventrículo direito e o tronco pulmonar, com uma válvula tricúspide suturada em seu interior sem anel de suporte, permitindo, assim, um mecanismo de fluxo unidirecional. De maio de 1986 a outubro de 1987, 5 crianças foram submetidas à operação de Rastelli empregando-se este tipo de conduto valvulado. Três eram do sexo feminino e 2, do masculino, variando a idade de 1 a 8 anos x 5). Três pacientes tinham transposição das grandes artérias, comunicação interventricular (CIV) e estenose subpulmonar. Uma criança era portadora de atresia pulmonar com CIV e de um shunt prévio tipo Waterston e, finalmente, a outra tinha um tronco arterial comum tipo II. Dois doentes faleceram de causas não relacionadas ao tipo de conduto valvulado utilizado. O conduto valvulado de pericárdio bovino preservado em glutaraldeído mostrou excelente flexibilidade, facilitando o manuseio cirúrgico e permitindo perfeita adaptabilidade dentro do saco pericárdico. A ausência de anel de suporte tem a vantagem de eliminar qualquer gradiente e de abolir o turbilhonamento do sangue - causas reconhecidas de calcificação.The present report describes the initial experience with the Rastelli operation utilizing a composite graft of glutaraldehyde preserved bovine pericardium. The graft is made up of a tube which serves to reconstruct the outflow tract of the right ventricle and the pulmonary artery, and an inner tricuspid valve, without a supporting ring, which provides the tube with a one-way flow mechanism. From May, 1986 to October, 1987, five children were submitted to Rastelli operation utilizing this valved tube. Three were female and two male, ranging in age from 1 e to 8 years (mean 5 years). Three had transposition of the great arteries, VSD and subpulmonic stenosis, one had pulmonary atresia, VSD and a previous Waterston shunt, and one had a type II truncus arteriosus. Two patients died of causes unrelated to the type of the conduit used. The valved conduit of preserved bovine pericardium is easy to handle due to its excellent flexibility, allowing perfect adaptability inside the pericardial sac. The absence of a supporting ring abolish gradient across the conduit and turbulence which are recognized causes of calcification.

Carlos R Moraes; Jorge V Rodrigues; Cláudio A Gomes; Lorella Marinucci; Cleuza Lapa Santos; Tereza Cristina Coelho; Ivan de Lima Cavalcanti

1988-01-01

313

Operação de Rastelli utilizando-se conduto valvulado de pericárdio bovino: experiência inicial/ Rastelli operation with bovine pericardium valved conduit: early experience  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O presente trabalho descreve a experiência inicial com a operação de Rastelli, utilizando-se um conduto valvulado de pericárdio bovino preservado em glutaraldeído. O enxerto consta de um conduto, que serve para reconstruir a via de saída do ventrículo direito e o tronco pulmonar, com uma válvula tricúspide suturada em seu interior sem anel de suporte, permitindo, assim, um mecanismo de fluxo unidirecional. De maio de 1986 a outubro de 1987, 5 crianças foram subm (more) etidas à operação de Rastelli empregando-se este tipo de conduto valvulado. Três eram do sexo feminino e 2, do masculino, variando a idade de 1 a 8 anos x 5). Três pacientes tinham transposição das grandes artérias, comunicação interventricular (CIV) e estenose subpulmonar. Uma criança era portadora de atresia pulmonar com CIV e de um shunt prévio tipo Waterston e, finalmente, a outra tinha um tronco arterial comum tipo II. Dois doentes faleceram de causas não relacionadas ao tipo de conduto valvulado utilizado. O conduto valvulado de pericárdio bovino preservado em glutaraldeído mostrou excelente flexibilidade, facilitando o manuseio cirúrgico e permitindo perfeita adaptabilidade dentro do saco pericárdico. A ausência de anel de suporte tem a vantagem de eliminar qualquer gradiente e de abolir o turbilhonamento do sangue - causas reconhecidas de calcificação. Abstract in english The present report describes the initial experience with the Rastelli operation utilizing a composite graft of glutaraldehyde preserved bovine pericardium. The graft is made up of a tube which serves to reconstruct the outflow tract of the right ventricle and the pulmonary artery, and an inner tricuspid valve, without a supporting ring, which provides the tube with a one-way flow mechanism. From May, 1986 to October, 1987, five children were submitted to Rastelli operatio (more) n utilizing this valved tube. Three were female and two male, ranging in age from 1 e to 8 years (mean 5 years). Three had transposition of the great arteries, VSD and subpulmonic stenosis, one had pulmonary atresia, VSD and a previous Waterston shunt, and one had a type II truncus arteriosus. Two patients died of causes unrelated to the type of the conduit used. The valved conduit of preserved bovine pericardium is easy to handle due to its excellent flexibility, allowing perfect adaptability inside the pericardial sac. The absence of a supporting ring abolish gradient across the conduit and turbulence which are recognized causes of calcification.

Moraes, Carlos R; Rodrigues, Jorge V; Gomes, Cláudio A; Marinucci, Lorella; Santos, Cleuza Lapa; Coelho, Tereza Cristina; Cavalcanti, Ivan de Lima

1988-08-01

314

Utilization of Adipose-Derived Stem Cells to Fabricate Scaffold-less Tissue Engineered Neural Conduits In Vitro  

Science.gov (United States)

Peripheral nerve injuries resulting from trauma or disease often necessitate surgical intervention. While the gold standard for such repairs utilizes nerve autografts, alternatives that do not require invasive harvesting of autologous nerve tissues are currently being designed and evaluated. We previously established the use of scaffold-less engineered neural conduits fabricated from primary cells as one such alternative in sciatic nerve repair in rats (Baltich, 2010; Adams 2011). The present study establishes protocols for fabricating neural conduits from adipose-derived stem cells (ASCs) differentiated to either a fibroblast or neural lineage and co-cultured into a three-dimensional scaffold-less tissue engineered neural conduit. Addition of ascorbic acid-2-phosphate and fibroblast growth factor FGF-2 to the medium induced and differentiated ASCs to a fibroblast lineage in over 90% of the cell population, as confirmed by collagen I expression. ASC-differentiated fibroblasts formed monolayers, delaminated and formed 3-D conduits. Neurospheres were formed by culturing ASCs on non-adherent surfaces in serum-free neurobasal medium with the addition of epidermal growth factor EGF and FGF-2. The addition of 10 ng EGF and 10 ng FGF-2 produced larger and more numerous neurospheres than treatments of lower EGF and FGF-2 concentrations. Subsequent differentiation to glial-like cells was confirmed by the expression of S100. ASC-derived fibroblast monolayers and neurospheres were co-cultured to fabricate a three-dimensional scaffold-less tissue engineered neural conduit. Their nerve-like structure and incorporation of glial-like cells which would associate with regenerating axons may make these novel, stem cell derived neural conduits an efficacious technology for repairing critical gaps following peripheral nerve injury.

Adams, Aaron M.; Arruda, Ellen M; Larkin, Lisa M

2011-01-01

315

Engine performance using vaporizing carburetor  

Energy Technology Data Exchange (ETDEWEB)

A simple device for mixture preparation in a spark ignition engine (vaporizing carburetor) with the ability to provide the engine with a homogeneous and correctly proportioned combustible mixture for different operating conditions has been tested in this study. This carburetor works on the principle of adiabatic vaporization of liquid gasoline fuel before introduction into the engine cylinder. This vaporization is achieved by passing atmospheric air, induced by engine suction, through the fuel. The performance and exhaust gas emissions of the engine were studied using different percentages of methanol-gasoline blends as well as pure gasoline, using both conventional and vaporizing carburetors. Results have shown that the vaporizing carburetor has numerous advantages over conventional carburetors. The advantages include improvement in fuel economy and exhaust emission, which can be attributed to the leaning out of the mixture that could be prepared by using the vaporizing carburetor. The vaporizing carburetor was found to be suitable for use with fuel blends. This is due to the high quality of mixture preparation and mixing of different fuels. (author)

Abu-Qudais, M.; Asfar, K.R.; Al-Azzam, R. [Jordan Univ. of Science and Technology, Irbid (Jordan). Dept. of Mechanical Engineering

2001-04-01

316

Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms  

Science.gov (United States)

In Strelec Quarry, the Czech Republic, an underground conduit network > 300 m long with a volume of ~ 104 m3 and a catchment of 7 km2 developed over 5 years by groundwater flow in Cretaceous marine quartz sandstone. Similar landforms at natural exposures (conduits, slot canyons, undercuts) are stabilized by case hardening and have stopped evolving. The quarry offers a unique opportunity to study conduit evolution in sandstone at local to regional scales, from the initial stage to maturity, and to characterize the erosion processes which may form natural landforms prior to stabilization. A new technique was developed to distinguish erodible and non-erodible sandstone surfaces. Based on measurements of relative erodibility, drilling resistance, ambient and water-saturated tensile strength (TS) at natural and quarry exposures three distinct kinds of surfaces were found. 1) Erodible sandstone exposed at ~ 60% of surfaces in quarry. This sandstone loses as much as 99% of TS when saturated. 2) Sub-vertical fracture surfaces that are non-erodible already prior to exposure at ground surface and which keep considerable TS if saturated. 3) Case hardened surfaces that start to form after exposure. In favorable conditions they became non-erodible and reach the full TS in just 6 years. An increase in the hydraulic gradient from ~ 0.005 to > 0.02 triggered conduit evolution, based on long-term monitoring of water table in 18 wells and inflows to the quarry. Rapidly evolving major conduits are characterized by a channel gradient of ~ 0.01, a flow velocity ~ 40 cm/s and sediment concentration ~ 10 g/l. Flow in openings with a discharge 1 ml/s and hydraulic gradient > 0.05 exceeds the erosion threshold and initiates piping. In the first phase of conduit evolution, fast concentrated flow mobilizes erodible sandstone between sets of parallel fractures in the shallow phreatic zone. In the second phase the conduit opening mainly expands vertically upward into the vadose zone by mass wasting of undercut sandstone slabs. Mass wasting is responsible for > 90% of mobilized sandstone. Sides of the mature conduits are protected by non-erodible fracture surfaces.Natural landforms were probably formed very rapidly by overland flow, piping and possibly fluidization during or at the end of the glacial periods when sandstone was not yet protected by case hardening.

Bruthans, Jiri; Svetlik, Daniel; Soukup, Jan; Schweigstillova, Jana; Valek, Jan; Sedlackova, Marketa; Mayo, Alan L.

2012-12-01

317

Copper vapor laser acoustic thermometry system  

Energy Technology Data Exchange (ETDEWEB)

A copper vapor laser (CVL) acoustic thermometry system is disclosed. The invention couples an acoustic pulse a predetermined distance into a laser tube by means of a transducer and an alumina rod such that an echo pulse is returned along the alumina rod to the point of entry. The time differential between the point of entry of the acoustic pulse into the laser tube and the exit of the echo pulse is related to the temperature at the predetermined distance within the laser tube. This information is processed and can provide an accurate indication of the average temperature within the laser tube.

Galkowski, Joseph J. (Livermore, CA)

1987-01-01

318

Quantifying vapor drift of dicamba herbicides applied to soybean.  

UK PubMed Central (United Kingdom)

Recent advances in biotechnology have produced cultivars of corn, soybean, and cotton resistant to the synthetic-auxin herbicide dicamba. This technology will allow dicamba herbicides to be applied in new crops, at new periods in the growing season, and over greatly expanded areas, including postemergence applications in soybean. From past and current use in corn and small grains, dicamba vapor drift and subsequent crop injury to sensitive broadleaf crops has been a frequent problem. In the present study, the authors measured dicamba vapor drift in the field from postemergence applications to soybean using greenhouse-grown soybean as a bioassay system. They found that when the volatile dimethylamine formulation is applied, vapor drift could be detected at mean concentrations of 0.56 g acid equivalent dicamba/ha (0.1% of the applied rate) at 21 m away from a treated 18.3?×?18.3 m plot. Applying the diglycolamine formulation of dicamba reduced vapor drift by 94.0%. With the dimethylamine formulation, the extent and severity of vapor drift was significantly correlated with air temperature, indicating elevated risks if dimethylamine dicamba is applied early to midsummer in many growing regions. Additional research is needed to more fully understand the effects of vapor drift exposures to nontarget crops and wild plants.

Egan JF; Mortensen DA

2012-05-01

319

Quantifying vapor drift of dicamba herbicides applied to soybean.  

Science.gov (United States)

Recent advances in biotechnology have produced cultivars of corn, soybean, and cotton resistant to the synthetic-auxin herbicide dicamba. This technology will allow dicamba herbicides to be applied in new crops, at new periods in the growing season, and over greatly expanded areas, including postemergence applications in soybean. From past and current use in corn and small grains, dicamba vapor drift and subsequent crop injury to sensitive broadleaf crops has been a frequent problem. In the present study, the authors measured dicamba vapor drift in the field from postemergence applications to soybean using greenhouse-grown soybean as a bioassay system. They found that when the volatile dimethylamine formulation is applied, vapor drift could be detected at mean concentrations of 0.56 g acid equivalent dicamba/ha (0.1% of the applied rate) at 21 m away from a treated 18.3?×?18.3 m plot. Applying the diglycolamine formulation of dicamba reduced vapor drift by 94.0%. With the dimethylamine formulation, the extent and severity of vapor drift was significantly correlated with air temperature, indicating elevated risks if dimethylamine dicamba is applied early to midsummer in many growing regions. Additional research is needed to more fully understand the effects of vapor drift exposures to nontarget crops and wild plants. PMID:22362509

Egan, J Franklin; Mortensen, David A

2012-03-13

320

Surface reaction of titanium beryllide with water vapor  

International Nuclear Information System (INIS)

[en] Beryllium is one of the candidate materials for the neutron multiplier in the tritium-breeding blanket. However, there are some problems related to the application of beryllium as a neutron multiplier, which include compatibility with structural materials, tritium inventory and reaction of beryllium with water vapor and oxygen in a LOCA accident. Titanium beryllides such as Be12Ti are known to have advantages over beryllium from the perspectives of higher melting point, lower chemical reactivity and lower swelling. Thus, these materials are promising alternatives of beryllium. The authors investigate here the reaction of titanium beryllides with water vapor at high temperatures, and it is found that Be12Ti is by far more tolerant to water vapor than beryllium. To clarify the high tolerance of Be12Ti to water vapor, the surface of Be12Ti used in the experiment was investigated by means of digital microscope, SEM, XRD and electron spectroscopy for chemical analysis (ESCA). These analyses suggest that some oxidized state of beryllium was formed on the surface of Be12Ti exposed to water vapor. In particular, the results of the ESCA analysis gave some clues to understanding the higher tolerance of Be12Ti to water vapor at high temperatures

2006-01-01

 
 
 
 
321

Does mercury vapor exposure increase urinary selenium excretion  

Energy Technology Data Exchange (ETDEWEB)

It has been reported that an increase of urinary selenium excretion may occur as a result of mercury vapor exposure. However, experimental data regarding the interaction between mercury vapor and selenium have yielded ambiguous results about the retention and elimination of selenium due to mercury vapor exposure and the decrease of selenium excretion due to mercury in the form of mercuric mercury (Hg/sup 2 +/). In this study, the authors measured urinary mercury and selenium in workers with or without exposure to mercury vapor to determine whether or not urinary selenium excretion was increased as a result of mercury vapor exposure. Urine samples were collected from 141 workers, 71 men and 70 women, whose extent of exposure to mercury vapor varied according to their job sites. Workers were divided into five groups according to their urinary mercury levels. The mercury level in group I was less than 2.8 nmol/mmol creatinine which means that this group was mostly free from mercury exposure. The average age was almost identical among the groups. For both sexes, group V (with the highest urinary mercury level) had the lowest urinary selenium level, but one-way variance analysis (ANOVA) did not reveal any significant variations of urinary selenium with urinary mercury levels; however, a weak but significant negative correlation between mercury and selenium was found in men.

Hongo, T.; Suzuki, T.; Himeno, S.; Watanabe, C.; Satoh, H.; Shimada, Y.

1985-01-01

322

Visualizing water-filled versus embolized status of xylem conduits by desktop x-ray microtomography.  

UK PubMed Central (United Kingdom)

BACKGROUND: The hydraulic conductivity of the stem is a major factor limiting the capability of trees to transport water from the soil to transpiring leaves. During drought conditions, the conducting capacity of xylem can be reduced by some conduits being filled with gas, i.e. embolized. In order to understand the dynamics of embolism formation and repair, considerable attention has been given to developing reliable and accurate methods for quantifying the phenomenon. In the past decade, non-destructive imaging of embolism formation in living plants has become possible. Magnetic resonance imaging has been used to visualize the distribution of water within the stem, but in most cases it is not possible to resolve individual cells. Recently, high-resolution synchrotron x-ray microtomography has been introduced as a tool to visualize the water contents of individual cells in vivo, providing unprecedented insight into the dynamics of embolism repair. We have investigated the potential of an x-ray tube -based microtomography setup to visualize and quantify xylem embolism and embolism repair in water-stressed young saplings and shoot tips of Silver and Curly birch (Betula pendula and B. pendula var. carelica). RESULTS: From the microtomography images, the water-filled versus gas-filled status of individual xylem conduits can be seen, and the proportion of stem cross-section that consists of embolized tissue can be calculated. Measuring the number of embolized vessels in the imaged area is a simple counting experiment. In the samples investigated, wood fibers were cavitated in a large proportion of the xylem cross-section shortly after watering of the plant was stopped, but the number of embolized vessels remained low several days into a drought period. Under conditions of low evaporative demand, also refilling of previously embolized conduits was observed. CONCLUSIONS: Desktop x-ray microtomography is shown to be an effective method for evaluating the water-filled versus embolized status of the stem xylem in a small living sapling. Due to its non-destructive nature, the risk of inducing embolisms during sampling is greatly reduced. Compared with synchrotron imaging beamlines, desktop microtomography offers easier accessibility, while maintaining sufficient resolution to visualize the water contents of individual cells.

Suuronen JP; Peura M; Fagerstedt K; Serimaa R

2013-01-01

323

Extracardiac conduit in total cavopulmonary connection/ Conduto extracardíaco na derivação cavopulmonar total  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: Avaliar a utilização de conduto extracardíaco na confecção de derivação cavopulmonar total nos diferentes tipos de cardiopatias complexas nas quais está indicado este tipo de correção. MÉTODO: Entre maio de 2000 e janeiro de 2003, foram operados 18 pacientes, 10 do sexo masculino, com idades entre 1 e 12 anos e peso variando de 11 a 29 quilos. O diagnóstico principal foi atresia tricúspide em oito pacientes, conexão atrioventricular univentricular (more) em oito e defeito total do septo atrioventricular desbalanceado em dois. Apenas um paciente foi operado sem cirurgia paliativa prévia. A operação foi realizada com emprego de circulação extracorpórea com temperatura acima de 32ºC orofaríngea e sem isquemia aórtica. Foram empregados, entre a veia cava inferior e a circulação pulmonar, 10 tubos de PTFE, quatro de Hemashield e quatro de pericárdio bovino, com números variando de 16 a 22mm de diâmetro. RESULTADOS: Ocorreram quatro casos de trombose no tubo, todos reoperados, com um óbito. Em um paciente, após 69 dias da operação, foi realizado "takedown" para Glenn bidirecional. Entre os 18 pacientes ocorreram três óbitos, um por trombose do tubo e dois por síndrome de baixo débito no pós-operatório imediato. CONCLUSÃO: O emprego de tubo extracardíaco já faz parte da técnica de derivação cavopulmonar total, mas sua indicação merece cuidados especiais. Abstract in english OBJECTIVE: This study evaluates a new technique of an extracardiac conduit in total cavopulmonary connection in complex congenital heart disease. METHODS: Between May 2000 and October 2002, 18 extracardiac conduit surgeries were performed. The patients' weights ranged from 11 to 29 kilograms, the ages ranged from 1 to 12 years old and 10 patients were male. There were eight patients with tricuspid atresia, eight with univentricular heart, and two with unbalanced total atr (more) ioventricular septal defect. There were 17 patients who had been submitted to a previous palliative surgery. The surgery was performed at over 32º centigrade without aortic ischemia. Ten PTFE, 4 Hemashield and 4 bovine pericardium tubes were used with diameters ranging from 16 to 22 mm. RESULTS: There were four cases of tube thrombosis and these patients were a reoperation was performed with one death. In one patient a takedown was performed on the 69th postoperative day. There were three deaths, one due to tube thrombosis and two due to low cardiac output. CONCLUSION: Extracardiac conduit is already used for total cavopulmonary connection, but despite encouraging early results, a longer follow-up is necessary to prove its real advantages.

Paulista, Paulo Paredes; Souza, Luiz Carlos Bento de; Chaccur, Paulo; Issa, Mário; Almeida, Antonio Flávio Sanches de; Guerra, Ana Luiza Paulista; Arnoni, Renato Tambellini; Paulista, Paulo Henrique Dagola; Santana, Maria Virginia Tavares

2003-09-01

324

Coupled evolution of magma chambers and flow in conduits during large volcanic eruptions  

Science.gov (United States)

The largest silicic and mafic volcanic eruptions in the geologic record, Supervolcano and Large Igneous Province (LIP) eruptions, are distinguished by differences in surface emplacement mode, geologic context, magma volatile content, viscosity, and reservoir depth. However, these large eruptions also share several common features. Individual eruptions of both types emplace roughly the same total volume (10^3 - 10^4 km^3) of remarkably homogeneous magma that likely comes from a single reservoir. In addition, they both release large quantities of volatiles, and hence individual eruptions may significantly perturb global climate. We have developed a model that couples conduit flow and magma chamber deformation, allowing us to study both eruption types. Steady, one-dimensional multiphase flow of magma containing crystals, exsolved water, and CO_2 in a cylindrical conduit is coupled to pressure evolution within an ellipsoidal magma chamber beneath a free surface. LIP eruptions are characterized by gas-driven flow of mafic lava that may be sustained past the cessation of chamber overpressure, much like a siphon. Eruptions cease when the yield strength of the country rocks is reached and the (generally Moho-level) chamber or the conduit implodes, resulting in steady discharge and atmospheric volatile loading. In contrast, more shallow silicic lavas such as the Fish Canyon Tuff erupt through rapid mobilization of a long-lived crystal-rich mush. The crystal-rich mush is a yield strength fluid, which we model using the von Mises criterion for mobilization. If the trigger for mobilization of the mush leads directly to eruption, time-progressive yielding due to mass removal results in a fluid magma chamber that grows as the eruption proceeds, until free-surface stresses induce roof collapse and caldera formation. Chamber pressure evolution may be buffered by the mobilization of the mush, maintaining overpressure and high discharge throughout the eruption. This model suggests that differences between major volcanic eruption dynamics arise largely from different boundary conditions at the source region, which themselves are due to magma rheology and reservoir depth.

Karlstrom, L.; Manga, M.; Rudolph, M. L.

2010-12-01

325

Endothelium-dependent vasodilation of peripheral conduit arteries in patients with heart failure.  

UK PubMed Central (United Kingdom)

Endothelium-dependent vasodilation of peripheral resistance vessels is abnormal in patients with heart failure, but there are little in vivo data on endothelium-dependent vasodilation of peripheral conduit vessels. This study assessed endothelium-dependent vasodilation of forearm conduit and resistance vessels in normal subjects and patients with heart failure. The effects of intraarterial endothelium-dependent and endothelium-independent vasodilators on both forearm conduit (brachial artery) and resistance vessels were assessed in 9 patients with New York Heart Association class II-III heart failure and 11 normal subjects of similar age. Brachial artery diameter was measured by two-dimensional, moderate-frequency (8 MHz) ultrasound, and forearm blood flow was measured by strain gauge plethysmography. The endothelium-dependent vasodilator, methacholine (0.3 and 1.5 micrograms/min), increased brachial artery diameter by 7.6 +/- 1.3% and 12.2 +/- 1.5% in normal subjects as compared to 6.9 +/- 2.1% and 10.4 +/- 2.4% in patients with heart failure (P = NS, normal vs heart failure). The endothelium-independent vasodilator, nitroglycerin (0.15 microgram), also produced similar increases in brachial artery diameter in the two groups (8.2 +/- 1.3% in normal subjects vs 11.1 +/- 1.4% in patients with heart failure, P = NS). In contrast, forearm blood flow responses to methacholine were significantly (P < .05) greater in normal subjects (4.1 +/- 0.5 and 9.2 +/- 1.4 mL/min/100 mL forearm volume) than in patients with heart failure (2.0 +/- 0.8 and 5.1 +/- 1.3 mL/min/100 mL forearm volume). Forearm blood flow responses to the endothelium-independent vasodilator, sodium nitroprusside, were similar between the two groups. This study suggests that endothelium-dependent and endothelium-independent vasodilation of the brachial artery is not impaired in patients with class II-III heart failure. This finding contrasts with abnormal endothelium-dependent vasodilation of forearm resistance vessels. These data suggest that there are regional differences in endothelial function in patients with heart failure.

Bank AJ; Rector TS; Tschumperlin LK; Kraemer MD; Letourneau JG; Kubo SH

1994-10-01

326

Conduit changes and eruptive styles at Red Mountain cinder cone, AZ, USA  

Science.gov (United States)

Red Mountain volcano is a Pleistocene (ca. 740 ky) cinder cone north of Flagstaff, AZ, in the northern Mio- Recent San Francisco volcanic field. Red Mountain erupted onto Permian sedimentary rocks with low topographic relief, likely covered in some places by older flows. The cone evolved through several stages that erupted and emplaced cinder, lava flow, agglutinate, and clastogenic lava. The transition from cinder eruption to mild hawaiian-type fountaining is contrary to observed activity at cinder cones, but may provide insight into conduit processes during basaltic eruptions. Earliest strombolian eruptions built a cone as much as 400 m high. Agglutinate is a relatively minor constituent as are vulcanian bombs < 1 m in diameter. Near the end of strombolian eruptions lava flowed from the base of the cone, primarily toward the west. Continued lava flow caused rafting of ~15% of the cone, including the vent area. Eruptions transitioned to mild hawaiian, with agglutinate emplacement, lava flow, clastogenic flow, and minor scoria eruption. Agglutinate at 200-350 m on the inner face of the rafted cone suggests a relatively low fountain height. Successions up to 30 m thick 4 km from vent expose interbedded welded cinder, agglutinate, clastogenic flow, and rooted lava flow. Activity at Red Mountain transitioned from strombolian to mild hawaiian, in opposition to most cinder cones. Hawaiian activity is generally attributed to a higher rate of magma flux than strombolian. Some change in the conduit clearly occurred causing either an increase in flux rate and/or a significant change in the vesiculation depth below the vent. We suggest two possibilities: 1) the rafting collapse of the cone, which decreased the conduit length by as much as 350 m, caused a significant change in the pressure profile, which in turn affected both the onset of bubble nucleation and the path length for bubble coalescence. This in turn caused less bubble/melt segregation and steadier (mild hawaiian) eruption. 2) A sudden increase in magma flux may have caused instability and collapse of the cone, with concomitant change in eruptive style.

Riggs, N. R.; Duffield, W. A.; Cashman, K. V.; Zimmer, B. W.

2006-12-01

327

Extracardiac conduit in total cavopulmonary connection Conduto extracardíaco na derivação cavopulmonar total  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: This study evaluates a new technique of an extracardiac conduit in total cavopulmonary connection in complex congenital heart disease. METHODS: Between May 2000 and October 2002, 18 extracardiac conduit surgeries were performed. The patients' weights ranged from 11 to 29 kilograms, the ages ranged from 1 to 12 years old and 10 patients were male. There were eight patients with tricuspid atresia, eight with univentricular heart, and two with unbalanced total atrioventricular septal defect. There were 17 patients who had been submitted to a previous palliative surgery. The surgery was performed at over 32º centigrade without aortic ischemia. Ten PTFE, 4 Hemashield and 4 bovine pericardium tubes were used with diameters ranging from 16 to 22 mm. RESULTS: There were four cases of tube thrombosis and these patients were a reoperation was performed with one death. In one patient a takedown was performed on the 69th postoperative day. There were three deaths, one due to tube thrombosis and two due to low cardiac output. CONCLUSION: Extracardiac conduit is already used for total cavopulmonary connection, but despite encouraging early results, a longer follow-up is necessary to prove its real advantages.OBJETIVO: Avaliar a utilização de conduto extracardíaco na confecção de derivação cavopulmonar total nos diferentes tipos de cardiopatias complexas nas quais está indicado este tipo de correção. MÉTODO: Entre maio de 2000 e janeiro de 2003, foram operados 18 pacientes, 10 do sexo masculino, com idades entre 1 e 12 anos e peso variando de 11 a 29 quilos. O diagnóstico principal foi atresia tricúspide em oito pacientes, conexão atrioventricular univentricular em oito e defeito total do septo atrioventricular desbalanceado em dois. Apenas um paciente foi operado sem cirurgia paliativa prévia. A operação foi realizada com emprego de circulação extracorpórea com temperatura acima de 32ºC orofaríngea e sem isquemia aórtica. Foram empregados, entre a veia cava inferior e a circulação pulmonar, 10 tubos de PTFE, quatro de Hemashield e quatro de pericárdio bovino, com números variando de 16 a 22mm de diâmetro. RESULTADOS: Ocorreram quatro casos de trombose no tubo, todos reoperados, com um óbito. Em um paciente, após 69 dias da operação, foi realizado "takedown" para Glenn bidirecional. Entre os 18 pacientes ocorreram três óbitos, um por trombose do tubo e dois por síndrome de baixo débito no pós-operatório imediato. CONCLUSÃO: O emprego de tubo extracardíaco já faz parte da técnica de derivação cavopulmonar total, mas sua indicação merece cuidados especiais.

Paulo Paredes Paulista; Luiz Carlos Bento de Souza; Paulo Chaccur; Mário Issa; Antonio Flávio Sanches de Almeida; Ana Luiza Paulista Guerra; Renato Tambellini Arnoni; Paulo Henrique Dagola Paulista; Maria Virginia Tavares Santana

2003-01-01

328

Portable vapor diffusion coefficient meter  

Science.gov (United States)

An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

329

Solar energy for LNG vaporization  

Energy Technology Data Exchange (ETDEWEB)

Disclosed is an apparatus for vaporizing a normally gaseous fluid which is in liquefied state which apparatus employs solar energy for heating a second fluid which preferably is water, which solar heated second fluid is passed into heat exchange relationship with said liquefied gaseous fluid for its vaporization. The preferred liquefied gaseous fluid is liquefied natural gas (LNG) and the second fluid preferably is water which optionally contains an anti-freeze additive for prevention of freezing of the water during the operation.

Hong, C.C.; Morse, W.F.; Price, D.E.

1982-05-25

330

Vapor deposition of hardened niobium  

Energy Technology Data Exchange (ETDEWEB)

A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)

1983-04-19

331

Circuitous embolic hemorrhagic stroke: carotid pseudoaneurysm to fetal posterior cerebral artery conduit: a case report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Introduction The cervical internal carotid artery (ICA) is susceptible to injury through various mechanisms, including dissection, which can lead to pseudoaneurysm formation. Pathological processes affecting the ICA, in association with an ipsilateral fetal posterior cerebral artery (PCA), resulting in parieto-occipital strokes are rarely reported. Case Presentation We present a patient with a left PCA territory, presumably embolic, stroke with early hemorrhagic transformation. The identified nidus of the embolus was a carotid artery pseudoaneurysm. Manifestations included right homonymous hemianopsia with right hemiparesis and hemisensory loss. Conclusion Our case is unique, and of clinical interest, because it illustrates both the potential anterior-posterior circulation conduit provided by a fetal origin PCA as well as the apparent early hemorrhagic transformation of embolic infarcts that can lead to further confusion from a mechanistic standpoint.

Hoque Romy; Gonzalez-Toledo Eduardo; Minagar Alireza; Kelley Roger E

2008-01-01

332

SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN  

International Nuclear Information System (INIS)

Eruptive conduit geometry has direct relation to number of waste packages that would be damaged if a new volcano were to form at the proposed Yucca Mountain radioactive waste repository, and therefore is a key factor in predicting the consequences of such an eruption. Current risk calculations treat conduits as having circular plan view and range from a few meters to 150 m diameter at repository depths (?300 m). We present new observations of shallow basaltic plumbing at analog sites aimed at testing these parameter values. East Grants Ridge. NM, is a remnant of a ?2.6 Ma alkali basaltic volcano with a chain of 2-3 vents that fed ?10-km long lava flows. The south side of the ridge exposes a plug of vertically jointed, dense basalt that intruded rhyolitic tuffs. The plug is exposed vertically for ?125 m, including 40 m beneath the paleosurface, and has a relatively constant width of ?135 m with no indication of downward narrowing. The size of the plug in the third dimension is not well known but could extend laterally up to ?1.5 km beneath the chain of vents. Paiute Ridge, NV, is an 8.6 Ma alkali basalt intrusion into Paleozoic carbonate and shale and Miocene silicic tuffs and includes extrusive equivalents. Dikes, small sills and lopoliths, scoria, and flows are exposed in a 2 km-wide graben. Depth of intrusion has been estimated at 100-250 m beneath the paleosurface. Dikes range from 3-20 m in width and produced limited contact vitrophyre in the host tuff. At least one sub-volcanic neck is preserved. The top of the plug is ?27 m lower than the base of related basalt flows 1 km distant. This neck is irregularly shaped by intersection of feeder dikes and has a sheath of mixed basaltic magma and host tuff (with both breccia and fluidal textures). The basalt interior of the plug is ?100 m x 70 m in map view but inclusion of the mixed zone increases this to ?220 m x 110 m. Basalt Ridge, NV, contains two remnants (9.1 Ma; 8.8 Ma) of basalt dikes, vent, spatter, scoria, and flow facies, with exposures to ?270 m beneath the paleosurface. Basalt Ridge ''East'' (BRE) contains breccias, agglutinates, and flows capping a linear ridge for 1,600 m; feeder dikes extend laterally beyond the eruptive products. The adjacent canyon reveals gradual decrease in feeder thickness from an 80-100 m-wide vent to a 40 m-wide zone of dikes plus host tuff (35 m beneath paleosurface), to 1-2 dikes in a 4 m-wide zone (270 m beneath paleosurface). BRE reveals no ''conduit'' extending to significant depth. Instead, multiple thin dikes rise vertically in non-welded and welded tuffs at repository depths. The above observations are roughly consistent with the range of conduit diameters currently used in consequence calculations, although they may support an extension of the size range so that some large diameters are accounted for at lower probabilities

2005-01-01

333

SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN  

Energy Technology Data Exchange (ETDEWEB)

Eruptive conduit geometry has direct relation to number of waste packages that would be damaged if a new volcano were to form at the proposed Yucca Mountain radioactive waste repository, and therefore is a key factor in predicting the consequences of such an eruption. Current risk calculations treat conduits as having circular plan view and range from a few meters to 150 m diameter at repository depths ({approx}300 m). We present new observations of shallow basaltic plumbing at analog sites aimed at testing these parameter values. East Grants Ridge. NM, is a remnant of a {approx}2.6 Ma alkali basaltic volcano with a chain of 2-3 vents that fed {approx}10-km long lava flows. The south side of the ridge exposes a plug of vertically jointed, dense basalt that intruded rhyolitic tuffs. The plug is exposed vertically for {approx}125 m, including 40 m beneath the paleosurface, and has a relatively constant width of {approx}135 m with no indication of downward narrowing. The size of the plug in the third dimension is not well known but could extend laterally up to {approx}1.5 km beneath the chain of vents. Paiute Ridge, NV, is an 8.6 Ma alkali basalt intrusion into Paleozoic carbonate and shale and Miocene silicic tuffs and includes extrusive equivalents. Dikes, small sills and lopoliths, scoria, and flows are exposed in a 2 km-wide graben. Depth of intrusion has been estimated at 100-250 m beneath the paleosurface. Dikes range from 3-20 m in width and produced limited contact vitrophyre in the host tuff. At least one sub-volcanic neck is preserved. The top of the plug is {approx}27 m lower than the base of related basalt flows 1 km distant. This neck is irregularly shaped by intersection of feeder dikes and has a sheath of mixed basaltic magma and host tuff (with both breccia and fluidal textures). The basalt interior of the plug is {approx}100 m x 70 m in map view but inclusion of the mixed zone increases this to {approx}220 m x 110 m. Basalt Ridge, NV, contains two remnants (9.1 Ma; 8.8 Ma) of basalt dikes, vent, spatter, scoria, and flow facies, with exposures to {approx}270 m beneath the paleosurface. Basalt Ridge ''East'' (BRE) contains breccias, agglutinates, and flows capping a linear ridge for 1,600 m; feeder dikes extend laterally beyond the eruptive products. The adjacent canyon reveals gradual decrease in feeder thickness from an 80-100 m-wide vent to a 40 m-wide zone of dikes plus host tuff (35 m beneath paleosurface), to 1-2 dikes in a 4 m-wide zone (270 m beneath paleosurface). BRE reveals no ''conduit'' extending to significant depth. Instead, multiple thin dikes rise vertically in non-welded and welded tuffs at repository depths. The above observations are roughly consistent with the range of conduit diameters currently used in consequence calculations, although they may support an extension of the size range so that some large diameters are accounted for at lower probabilities.

D.J. Krier; G.N. Keating; G.A. Valentine

2005-08-26

334

Modelling of dual stability in a cable-in-conduit conductor  

Energy Technology Data Exchange (ETDEWEB)

A zero dimensional stability model has been developed for cable-in-conduit superconductors. The model is effective in simulating the multi-valued stability behaviour in the vicinity of the limiting current. This has been by modifying the helium heat transfer coefficient to account for inertial and fractional terms which affect the induced helium flow. Although this effect is treated qualitatively on a pseudo-one-dimensional basis, the model can reproduce with remarkable accuracy the multi-valued stability behaviour shown in earlier measurements performed by Lue, et al. The influence of the steady state mass flow is discussed, and a first order approximation of its effect is introduced in the model showing how an increase of the steady flow tends to wash-away'' the multiple stability region as observed in the experiment.

Bottura, L. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.). NET Design Team); Minervini, J.V. (Los Alamos National Lab., NM (USA))

1990-01-01

335

Detection of the normal zone with cowound sensors in cable-in conduit conductors  

International Nuclear Information System (INIS)

[en] Tokamaks in the future will use superconducting cable-in-conduit- conductors (CICC) in all poloidal field (PF) and toroidal field (TF) magnets. Conventional quench detection, the measurement of small resistive normal zone voltages (4 kV). In the quench detection design for TPX, we have considered several different locations for internal co-wound voltage sensors in the cable cross-section as the primary mechanism to cancel this inductive noise. The Noise Rejection Experiment (NRE) at LLNL has been designed to evaluate which internal locations will produce the best inductive- noise cancellation, and provide us with experimental data for comparison with previously developed theory. The details of the experiments and resulting data are presented and analyzed

1996-01-01

336

Nb/sub 3/Sn cable-in-conduit conductor tests  

International Nuclear Information System (INIS)

[en] Several tests have been performed on Nb/sub 3/Sn cable-in-conduit conductors in an effort to define the stability margin of the conductor to be used in the Westinghouse Large Coil Program (LCP) coil. One of the test conductors contained a 6*3/sup 4/ Nb/sub 3/Sn cable almost identical to the final LCP design; only the void fraction was different. It was not possible to quench this conductor at the limits of the test facility, 20 kA and 8-T applied field. Supporting tests were performed on smaller conductors: one of similar construction but with one-third as many composite strands and one that contained only one triplex of composite strands. Tests on both these conductors indicate that the full-size conductor should indeed have been stable against much higher energies than we were able to inject. This magnet is for fusion applications. 7 refs

1979-11-16

337

Parametric study of the stability margin of cable-in-conduit superconductors: theory  

Energy Technology Data Exchange (ETDEWEB)

Recently, Lue, Miller, and Dresner reported that the stability margin of cable-in-conduit superconductors is multivalued for certain combinations of transport current, ambient helium pressure, and externally imposed helium flow. There is a limiting transport current below which the stability margin is single-valued and equal to the upper stability margin. This theory is used here to determine the scaling of the limiting transport current with critical temperature, ambient helium temperature, resistivity of copper, length of the heated zone, duration of the heat pulse, hydraulic diameter of the helium-filled part of the cable, volume fraction of copper in the metal, and volume fraction of metal in the cable. Combined with experimental data, the scaling relation provides a sound basis for design.

Dresner, L.

1980-01-01

338

Parametric study of the stability margin of cable-in-conduit superconductors: theory  

International Nuclear Information System (INIS)

Recently, Lue, Miller, and Dresner reported that the stability margin of cable-in-conduit superconductors is multivalued for certain combinations of transport current, ambient helium pressure, and externally imposed helium flow. There is a limiting transport current below which the stability margin is single-valued and equal to the upper stability margin. This theory is used here to determine the scaling of the limiting transport current with critical temperature, ambient helium temperature, resistivity of copper, length of the heated zone, duration of the heat pulse, hydraulic diameter of the helium-filled part of the cable, volume fraction of copper in the metal, and volume fraction of metal in the cable. Combined with experimental data, the scaling relation provides a sound basis for design

1980-10-02

339

Coupling losses in cable-in-conduit conductors for LHD poloidal coils  

International Nuclear Information System (INIS)

Coupling losses in Large Helical Device (LHD) poloidal coils have been measured during operations with three different waveforms. The superconductors of the poloidal coils are cable-in-conduit conductors (CICC) cooled by supercritical helium. In the experiments, the operating currents were simultaneously changed with a given waveform, and the enthalpy increase due to the losses was observed at the inlet and outlet of the helium coolant. Inter-strand coupling currents through resistive contact points mainly caused the losses. Time constants of the coupling currents are estimated by using analytical expressions with a circuit model. The results indicate a broad distribution of the time constants from the order of 10-1000 s.

2003-01-01

340

Numerical modeling of thermal behavior of fluid conduit flow with transport delay  

Energy Technology Data Exchange (ETDEWEB)

Fluid mass and energy flows in air-conditioning systems vary with the changing output demand. In lengthy or complex ductwork and pipework, the accuracy in simulating the dynamic network behavior is greatly affected by the accuracy in modeling the radial energy losses and the axial transport lag. Transport delay consideration is also vital in the study of heat exchanger dynamics. This paper reviews the development of transport delay models in fluid conduit flow. A new numerical model is recommended in which the thermal behavior of fluid elements can be traced per physical distance traveled in unit time step. Justifications by sensitivity and frequency response analyses were performed. The results of analytical, experimental, as well as intermodel comparisons demonstrate the promising accuracy of the numerical model introduced.

Chow, T.T. [City Univ. of Hong Kong (Hong Kong). Div. of Technology; Ip, F.; Dunn, A. [Univ. of Hong Kong (Hong Kong). Faculty of Engineering; Tse, W.L. [China Light and Power Co., Ltd., Hong Kong (Hong Kong)

1996-12-31

 
 
 
 
341

Recurrent cervical esophageal stenosis after colon conduit failure: Use of myocutaneous flap  

Directory of Open Access Journals (Sweden)

Full Text Available A 53-year-old male developed cervical esophageal stenosis after esophageal bypass surgery using a right colon conduit. The esophageal bypass surgery was performed to treat multiple esophageal strictures resulting from corrosive ingestion three years prior to presentation. Although the patient underwent several endoscopic stricture dilatations after surgery, he continued to suffer from recurrent esophageal stenosis. We planned cervical patch esophagoplasty with a pedicled skin flap of sternocleidomastoid (SCM) muscle. Postoperative recovery was successful, and the patient could eat a solid meal without difficulty and has been well for 18 mo. SCM flap esophagoplasty is an easier and safer method of managing complicated and recurrent cervical esophageal strictures than other operations.

Young Jo Sa; Young Du Kim; Chi Kyung Kim; Jong Kyung Park; Seok Whan Moon

2013-01-01

342

Recurrent cervical esophageal stenosis after colon conduit failure: use of myocutaneous flap.  

Science.gov (United States)

A 53-year-old male developed cervical esophageal stenosis after esophageal bypass surgery using a right colon conduit. The esophageal bypass surgery was performed to treat multiple esophageal strictures resulting from corrosive ingestion three years prior to presentation. Although the patient underwent several endoscopic stricture dilatations after surgery, he continued to suffer from recurrent esophageal stenosis. We planned cervical patch esophagoplasty with a pedicled skin flap of sternocleidomastoid (SCM) muscle. Postoperative recovery was successful, and the patient could eat a solid meal without difficulty and has been well for 18 mo. SCM flap esophagoplasty is an easier and safer method of managing complicated and recurrent cervical esophageal strictures than other operations. PMID:23345956

Sa, Young Jo; Kim, Young Du; Kim, Chi Kyung; Park, Jong Kyung; Moon, Seok Whan

2013-01-14

343

Total cavopulmonary connection with innovative combined lateral tunnel and extracardiac conduit in heterotaxy syndrome.  

Science.gov (United States)

Total cavopulmonary connection remains a challenging procedure when treating heterotaxy syndrome patients with a widely separate drainage of the inferior vena cava and the hepatic vein into the common atrium. We trimmed a Gore-Tex tube graft (W.L. Gore & Associates, Flagstaff, AZ) to form a skirt to cover both openings of the inferior vena cava and the hepatic vein. This tubular structure pierces the atrium and travels outside the heart, and then reaches the inferior side of the pulmonary artery to avoid pulmonary vein obstruction. We then sutured the pierced atriotomy margin to the conduit. This innovative procedure has been shown to accommodate the widely separated hepatic vein drainage with a promising outcome. PMID:22051298

Hsu, Kang-Hong; Chang, Chung-I

2011-10-31

344

Total cavopulmonary connection with innovative combined lateral tunnel and extracardiac conduit in heterotaxy syndrome.  

UK PubMed Central (United Kingdom)

Total cavopulmonary connection remains a challenging procedure when treating heterotaxy syndrome patients with a widely separate drainage of the inferior vena cava and the hepatic vein into the common atrium. We trimmed a Gore-Tex tube graft (W.L. Gore & Associates, Flagstaff, AZ) to form a skirt to cover both openings of the inferior vena cava and the hepatic vein. This tubular structure pierces the atrium and travels outside the heart, and then reaches the inferior side of the pulmonary artery to avoid pulmonary vein obstruction. We then sutured the pierced atriotomy margin to the conduit. This innovative procedure has been shown to accommodate the widely separated hepatic vein drainage with a promising outcome.

Hsu KH; Chang CI

2011-11-01

345

Conversion from incontinent conduit to continent cutaneous reservoir after renal transplant.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To describe the technique and outcomes of conversion of incontinent stoma to continent colonic reservoir after renal transplantation (RT). METHODS: From 2004 to 2009, 2 patients who underwent kidney transplants and incontinent stomas underwent takedown of their urostomy with construction of a right colon continent cutaneous pouch with an appendiceal catheterizable stoma. The conduit was used as an afferent limb and anastomosed to the distal ileal portion of the reservoir with ileocecal valve serving as the antireflux mechanism. Thus no ureteral anastomosis was necessary. RESULTS: Both patients had an uneventful postoperative course and are now completely continent. There have been no interval infections or renal graft deterioration with short term follow-up. CONCLUSION: Continent cutaneous urinary diversion after RT is feasible and can lead to a significant improvement in the quality of life. Further follow-up is necessary to ascertain the long-term results of this form of diversion.

Daneshmand S; Ahmadi H

2013-05-01

346

The strength and permeability of tuffisite-bearing andesite in volcanic conduits  

Directory of Open Access Journals (Sweden)

Full Text Available Tuffisites result from volcanically-induced subsurface fragmentation, transport and deposition, and are common in explosive volcanic environments. Their study provides direct insight to explosive volcanic processes operating within volcanic conduits. Here we report the influence of tuffisite veins on the fundamental physical properties of andesitic rocks. We find that: (1) strength is unaffected by the presence and/or orientation of tuffisites, (2) permeability doubles when tuffisites are oriented favorable (45 degrees to fluid flow), and (3) seismic wave velocities show a continuous increase with depth, independent of vein orientation. Although the influence of tuffisites on andesitic rock properties is modest, we emphasize that the material tested represents the post-eruptive state of tuffisite. Thus, these results delineate the upper boundary of strength and lower boundary of permeability and porosity. All evidence suggests that tuffisites become compacted and lithified on relatively short time scales, restoring the strength of the rock to their initial host rock values.

S. Kolzenburg; M. J. Heap; Y. Lavallée; J. K. Russell; P. G. Meredith; D. B. Dingwell

2012-01-01

347

Thymic medullar conduits-associated podoplanin promotes natural regulatory T cells.  

UK PubMed Central (United Kingdom)

Podoplanin, a mucin-like plasma membrane protein, is expressed by lymphatic endothelial cells and responsible for separation of blood and lymphatic circulation through activation of platelets. Here we show that podoplanin is also expressed by thymic fibroblastic reticular cells (tFRC), a novel thymic medulla stroma cell type associated with thymic conduits, and involved in development of natural regulatory T cells (nTreg). Young mice deficient in podoplanin lack nTreg owing to retardation of CD4(+)CD25(+) thymocytes in the cortex and missing differentiation of Foxp3(+) thymocytes in the medulla. This might be due to CCL21 that delocalizes upon deletion of the CCL21-binding podoplanin from medullar tFRC to cortex areas. The animals do not remain devoid of nTreg but generate them delayed within the first month resulting in Th2-biased hypergammaglobulinemia but not in the death-causing autoimmune phenotype of Foxp3-deficient Scurfy mice.

Fuertbauer E; Zaujec J; Uhrin P; Raab I; Weber M; Schachner H; Bauer M; Schütz GJ; Binder BR; Sixt M; Kerjaschki D; Stockinger H

2013-07-01

348

Rare earth vapor laser studies  

International Nuclear Information System (INIS)

The fluorescence decay rates of vapor phase neodymium aluminum chloride complex (Nd-Al-Cl) and neodymium-thd-chelate have been measured as functions of temperature, partial pressure and optical excitation intensity. Fluorescence quenching due to both ground and excited state collisions was observed in Nd-Al-Cl vapor. In constrast, quenching in the Nd-thd vapor was found to be dominated by multiquantum excitation of molecular vibrations. The fluorescence kinetics of Tb-Al-Cl vapor have also been examined under conditions of intense excitation of terbium 5d levels by a KrF laser source. Both prompt and delayed fluorescence of the 4f8(5D4) metastable level were observed together with evidence of excited-state collisional quenching. In laser amplifier experiments, a transient (greater than or equal to 10 ?sec) population inversion was produced in Nd-Al-Cl vapor with a small signal gain coefficient greater than or equal to 0.25%/cm and a stored energy density approximately equal to 35 J/liter. Available data for the rare earth vapors are related to scaling requirements of large amplifiers for laser fusion application

1977-10-20

349

Conduit dynamics for Vulcanian explosions at Soufriere Hills Volcano, Montserrat, from strainmeter data  

Science.gov (United States)

The Soufrière Hills Volcano (SHV), Montserrat, has been erupting for over 14 years, with three semi-continuous periods of extrusion (~1-2 yr) separated by three long pauses. The third pause ended in late July 2008 but subsequent activity was discontinuous and comprised two short periods of extrusion with explosive activity. Vulcanian explosions at SHV in July and December 2008 and on 3 January 2009 were recorded on the CALIPSO array with Sacks-Evertson dilatometers. (The CALIPSO array contains specialized instruments in four strategically located ~200m-deep-boreholes installed to investigate the dynamics of the SHV magmatic system). The explosions resulted in clear, coherent strain-steps (amplitude range ca. ~2-140 nanostrain). We report here on observations of strainmeter and microbarometer data, which allow us to describe the evolution of conduit dynamics in the explosions. The strain data are corrected for air pressure effects, and compared to seismic observations, plume heights to >12 km, and mass erupted, in order to constrain conduit pressure, and the dynamics of the events. The explosions share many similarities and strain data for these explosions are (mainly) characterized by contractive dilatation offset at all sites, from 5.4 to 9.6 km from the crater. Barometer data show the influence of atmospheric pressure changes on the dilatometer strains and yield further information on eruption dynamics. The strain steps are correlated with explosion plume height and mass erupted and may be useful for rapid assessment of aviation hazards from airborne ash. The CALIPSO instrument network is supported by NSF.

Chardot, L.; Voight, B.; Stewart, R.; Linde, A. T.; Sacks, S. I.; Hidayat, D.; Fournier, N.

2009-12-01

350

Rheology of Crystal- and Bubble-bearing Magmas: Insights into Volcanic Conduit Dynamics  

Science.gov (United States)

Magmas are multiphase mixtures composed of crystals and gas bubbles suspended in a silicate melt. The relative proportions of these phases and their interaction control the rheological behavior, the modality of emplacement within the Earth's crust and the eruption of magmas. The rheology of crystal- and bubble-bearing magmas (ranging from dilute suspensions to crystal mushes) has been experimentally investigated. Hydrous haplogranitic magmas containing variable amounts of quartz crystals (24-65 vol.%), and CO2-rich bubbles (9-12 vol.%) were deformed in simple shear with a Paterson-type rock deformation apparatus at high temperature (823-1023 K) and high pressure (200 MPa), in strain-rate stepping (10-5 s-1 - 4·10-3 s-1) from low to high deformation rate. The rheological results show that three-phase suspensions are characterized by strain rate-dependent rheology (non-Newtonian behavior). Two kinds of non-Newtonian behaviors were observed: shear thinning (decrease of viscosity with increasing strain rate) and shear thickening (increase of viscosity with increasing strain rate). Microstructural observations suggest that: shear thinning dominantly occurs in crystal-rich magmas (55-65 vol.% crystals) because of crystal size reduction and shear localization; shear thickening prevails in dilute suspensions (24-44 vol% crystals) due to outgassing promoted by bubble coalescence. To illustrate the impact of these new findings in magma rheology, we present two applications on volcanic conduits where magmas are characterized by shear thickening and shear thinning behavior. The two types of rheological behavior determine the modality of magma ascent in the volcanic conduit and, ultimately, the type of volcanic eruption.

Pistone, Mattia; Caricchi, Luca; Ulmer, Peter

2013-04-01

351

Theory and modelling of quench in cable-in-conduit superconducting magnets  

Energy Technology Data Exchange (ETDEWEB)

A new simple, self consistent theoretical model is presented that describes the phenomena of quench propagation in Cable-In-Conduit superconducting magnets. The model (Quencher) circumvents many of the difficulties associated with obtaining numerical solutions in more general existing models. Specifically, a factor of 30-50 is gained in CPU time over the general, explicit time dependent codes used to study typical quench events. The corresponding numerical implementation of the new model is described and the numerical results are shown to agree very well with those of the more general models, as well as with experimental data. Further, well justified approximations lead to the MacQuench model that is shown to be very accurate and considerably more efficient than the Quencher model. The MacQuench code is suitable for performing quench studies on a personal computer, requiring only several minutes of CPU time. In order to perform parametric studies on new conductor designs it is required to utilize a model such as MacQuench because of the high computational efficiency of this model. Finally, a set of analytic solutions for the problem of quench propagation in Cable-In-Conduit Conductors is presented. These analytic solutions represent the first such results that remain valid for the long time scales of interest during a quench process. The assumptions and the resulting simplifications that lead to the analytic solutions are discussed, and the regimes of validity of the various approximations are specified. The predictions of the analytic results are shown to be in very good agreement with numerical as well as experimental results. Important analytic scaling relations are verified by such comparisons, and the consequences of some of these scalings on currently designed superconducting magnets are discussed.

Shajii, A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

1994-04-01

352

Numerical simulation of explosive volcanic eruptions from the conduit flow to global atmospheric scales  

Directory of Open Access Journals (Sweden)

Full Text Available Volcanic eruptions are unsteady multiphase phenomena, which encompass many inter-related processes across the whole range of scales from molecular and microscopic to macroscopic, synoptic and global. We provide an overview of recent advances in numerical modelling of volcanic effects, from conduit and eruption column processes to those on the Earth s climate. Conduit flow models examine ascent dynamics and multiphase processes like fragmentation, chemical reactions and mass transfer below the Earth surface. Other models simulate atmospheric dispersal of the erupted gas-particle mixture, focusing on rapid processes occurring in the jet, the lower convective regions, and pyroclastic density currents. The ascending eruption column and intrusive gravity current generated by it, as well as sedimentation and ash dispersal from those flows in the immediate environment of the volcano are examined with modular and generic models. These apply simplifications to the equations describing the system depending on the specific focus of scrutiny. The atmospheric dispersion of volcanic clouds is simulated by ash tracking models. These are inadequate for the first hours of spreading in many cases but focus on long-range prediction of ash location to prevent hazardous aircraft - ash encounters. The climate impact is investigated with global models. All processes and effects of explosive eruptions cannot be simulated by a single model, due to the complexity and hugely contrasting spatial and temporal scales involved. There is now the opportunity to establish a closer integration between different models and to develop the first comprehensive description of explosive eruptions and of their effects on the ground, in the atmosphere, and on the global climate.

C. Textor; H. Graf; A. Longo; A. Neri; T. E. Ongaro; P. Papale; C. Timmreck; G. G. J. Ernst

2005-01-01

353

Boundary layer sources for the Asian anticyclone: Regional contributions to a vertical conduit  

Science.gov (United States)

transport of air from the planetary boundary layer (PBL) into the Asian Summer Monsoon anticyclone is investigated using backward trajectories initiated within the anti-cyclone at 100 mb and 200 mb during August 2011. Transport occurs through a well-defined conduit centered over the southern Tibetan plateau, where convection lofts air parcels into the anticyclone. The conduit, as a dynamical feature, is distinct from the anticyclone. Thus, while the anticyclone influences transport through the upper troposphere and lower stratosphere, it does not by itself define a transport pipeline through that region. To quantify model sensitivities, parcel trajectories are calculated using wind fields from multiple analysis data sets (European Centre for Medium-Range Weather Forecasts, National Center for Environmental Prediction's Global Forecasting System, and NASA's Modern-Era Retrospective Analysis for Research and Applications [MERRA]) and from synthetically modified data sets that explore the roles of vertical motion and horizontal resolution for discrepancies among these calculations. All calculations agree on the relative contributions to PBL sources for the anticyclone from large-scale regions with Tibetan Plateau and India/SE Asia being the most important. However, they disagree on the total fraction of air within the anticyclone that was recently in the PBL. At 200 mbar, calculations using MERRA are clear outliers due to problematic vertical motion in those data. Large differences among the different data sets at 100 mbar are more closely related to horizontal resolution. It is speculated that this reflects the importance of deep, small-scale convective updrafts for transport to 100 mbar.

Bergman, John W.; Fierli, Federico; Jensen, Eric J.; Honomichl, Shawn; Pan, Laura L.

2013-03-01

354

Chemical vapor deposition sciences  

Energy Technology Data Exchange (ETDEWEB)

Chemical vapor deposition (CVD) is a widely used method for depositing thin films of a variety of materials. Applications of CVD range from the fabrication of microelectronic devices to the deposition of protective coatings. New CVD processes are increasingly complex, with stringent requirements that make it more difficult to commercialize them in a timely fashion. However, a clear understanding of the fundamental science underlying a CVD process, as expressed through computer models, can substantially shorten the time required for reactor and process development. Research scientists at Sandia use a wide range of experimental and theoretical techniques for investigating the science of CVD. Experimental tools include optical probes for gas-phase and surface processes, a range of surface analytic techniques, molecular beam methods for gas/surface kinetics, flow visualization techniques and state-of-the-art crystal growth reactors. The theoretical strategy uses a structured approach to describe the coupled gas-phase and gas-surface chemistry, fluid dynamics, heat and mass transfer of a CVD process. The software used to describe chemical reaction mechanisms is easily adapted to codes that model a variety of reactor geometries. Carefully chosen experiments provide critical information on the chemical species, gas temperatures and flows that are necessary for model development and validation. This brochure provides basic information on Sandia`s capabilities in the physical and chemical sciences of CVD and related materials processing technologies. It contains a brief description of the major scientific and technical capabilities of the CVD staff and facilities, and a brief discussion of the approach that the staff uses to advance the scientific understanding of CVD processes.

NONE

1992-12-31

355

Massive Upper GI Haemorrhage Ending in Transhiatal Oesophagectomy with Gastric Pull through Following Conduit Repair of Pulmonary Atresia (Case Report)  

Directory of Open Access Journals (Sweden)

Full Text Available A five year old female with complex congenital heart disease developed gastrointestinal hemorrhage following VSD closure, RV-PA conduit, ligation of aneurysmal right MAPCA and clipping of modified pott-shunt. All conservative measures from cold saline lavage to left gastric artery embolisation were tried but none was successful

Dr. Ranjith Karthekeyan B.; Dr. Karthikeyan N S.; Dr. Rakesh M.G.; Dr. Suresh Rao K.G.; Dr. Mahesh Vakamudi; Dr. Balakrishnan K.R.

2007-01-01

356

Conduit fragmentation, cave patterns, and the localization of karst ground water basins: the Appalachians as a test case  

Directory of Open Access Journals (Sweden)

Full Text Available Because conduit systems in maturely developed karst aquifers have a low hydraulic resistance, aquifers drain easily and karst aquifers are subdivided into well-defined ground water basins. Ground water elevations are highest at basin boundaries; lowest at the spring where the ground water is discharged. Parameters that control the type of conduit development are (1) the effective hydraulic gradient, (2) the focus of the drainage basin, and (3) the karstifiability of the bedrock. Moderate to highly effective hydraulic gradients permit the runaway process that leads to single conduit caves and well ordered branchwork systems. Low hydraulic gradients allow many alternate flow paths and thus a large degree of fuzziness in the basin boundaries. Low gradient ground water basins also tend to merge due to rising water tables during periods of high discharge. Focus is provided by geological constraints that optimize discharge at specific locations that can evolve into karst springs. Karstifiability is a measure of the bulk rate at which aquifer rocks will dissolve. Fine grained, pure limestones and shaley dolomites mark the opposite ends of the range. The cave surveys of the Appalachian Highlands provide a data base that can be used to classify the lateral arrangements of conduit systems and thus determine the relative importance of the factors defined above.

White,W.B.; White,E.L.

2003-01-01

357

Spatial analysis of karst conduit networks and determination of parameters controlling the speleogenesis along preferential lithostratigraphic horizons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main objective of this thesis is to improve the understanding of the position and characteristics of karst conduits within a rock massif. Such a characterisation is an important issue in civil engineering and in hydrogeology. Today in practice dissolution voids are considered as random in most c...

Filipponi, Marco

358

A 40 kA NbTi cable in conduit conductor for the large poloidal field coils of net  

International Nuclear Information System (INIS)

[en] The main feature of this cable in conduit design is to separate the manufacture of the full length of the steel conduit (400 m) and of the cable in order to minimize the industrial risk and consequently the cost. A circular cross section for that cable seems to be the most suitable for that purpose: - axisymmetric cabling with full transposition of strands, - cable behaviour independent of the field orientation, - less deformation of subcables, - cross section remains circular when the cable is under tension and makes the slippage of the cable in the conduit easier, - butt welding of 8 m long tubes forming the conduit becomes simpler. The square external shape allows to minimize the amount of insulating material and consequently improves the overall current density of the coil. This conductor is aimed to large poloidal field coils for NET which do not require high field and in that case NbTi seems to be the best choice with regard to reliability and cost but Nb3Sn could be used as well. Stainless steel ribbons are inserted between subcables in order to reduce losses induced by the rapid field changes and also to improve the mechanical behaviour of the cable

1990-01-01

359

Comparasion of granisetron and metoclopramide for prevention of nausea and vomiting following total cystectomy and ileal conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study was to examine the use of granisetron in actual clinical practice and to compare effect of dose of 1 mg granisetron after total cystectomy plus ileal conduit with group of patients which received metoclopramide. Granisetron established total control of PONV in 93,33% pati...

La?evi? N.; Liki?-La?evi? I.; Krivi? B.; Filimonovi? J.; A?imovi? M.; Dragi?evi? D.; Argirovi? R.

360

Controls on magma permeability in the volcanic conduit during the climactic phase of the Kos Plateau Tuff eruption (Aegean Arc)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

X-ray computed microtomography (?CT) was applied to pumices from the largest Quaternary explosive eruption of the active South Aegean Arc (the Kos Plateau Tuff; KPT) in order to better understand magma permeability within volcanic conduits. Two different types of pumices (one with highly elongated b...

Degruyter, Wim; Bachmann, Olivier; Burgisser, Alain

 
 
 
 
361

FATIGUE PROPERTIES OF MODIFIED 316LN STAINLESS STEEL AT 4 K FOR HIGH FIELD CABLE-IN-CONDUIT APPLICATIONS  

International Nuclear Information System (INIS)

[en] Cable-In-Conduit-Conductor (CICC) alloys, exposed to Nb3Sn reaction heat-treatments, such as modified 316LN require a design specific database. A lack of fatigue life data (S-n curves) that could be applied in the design of the ITER CS and the NHMFL Series Connected Hybrid magnets is the impetus for the research presented here. The modified 316LN is distinguished by a lower carbon content and higher nitrogen content when compared to conventional 316LN. Because the interstitial alloying elements affect the mechanical properties significantly, it is necessary to characterize this alloy in a systematic way. In conjunction, to ensure magnet reliability and performance, several criteria and expectations must be met, including: high fatigue life at the operating stresses, optimal stress management at cryogenic temperatures and thin walled conduit to reduce coil mass. Tension-tension load control axial fatigue tests have good applicability to CICC solenoid magnet design, thus a series of 4 K strength versus fatigue life curves have been generated. In-situ samples of 316LN base metal, seam welded, butt welded and seam plus butt welded are removed directly from the conduit in order to address base and weld material fatigue life variability. The more than 30 fatigue tests show good grouping on the fatigue life curve and allow discretionary 4 K fatigue life predictions for conduit made with modified 316LN.

2010-04-08

362

Terrestrial analogs to lunar sinuous rilles - Kauhako Crater and channel, Kalaupapa, Molokai, and other Hawaiian lava conduit systems  

International Nuclear Information System (INIS)

Two source vents, one explosive and one effusive erupted to form a cinder cone and low lava shield that together compose the Kalaupapa peninsula of Molokai, Hawaii, A 50-100-m-wide channel/tube system extends 2.3 km northward from kauhako crater in the center of the shield. Based on modeling, a volume of up to about 0.2 cu km of lava erupted at a rate of 260 cu m/sec to flow through the Kauhako conduit system in one of the last eruptive episodes on the peninsula. Channel downcutting by thermal erosion occurred at a rate of about 10 micron/sec to help form the 30-m-deep conduit. Two smaller, secondary tube systems formed east of the main lava channel/tube. Several other lava conduit systems on the islands of Oahu and Hawaii were also compared to the Kauhako and lunar sinuous rille systems. These other lava conduits include Whittington, Kupaianaha, and Mauna Ulu lava tubes. Morphologically, the Hawaiian tube systems studied are very similar to lunar sinuous rilles in that they have deep head craters, sinuous channels, and gentle slopes. Thermal erosion is postulated to be an important factor in the formation of these terrestrial channel systems and by analogy is inferred to be an important process involved in the formation of lunar sinuous rilles. 28 refs.

1990-01-01

363

Ileal conduit without cystectomy may be an appropriate option in the treatment of intractable bladder pain syndrome/interstitial cystitis.  

UK PubMed Central (United Kingdom)

Abstract Objective. The aim of this study was to report the outcomes of urinary diversion for bladder pain syndrome/interstitial cystitis (BPS/IC) at a large university hospital over a period of more than 10 years. Material and methods. Chart reviews were performed for BPS/IC patients who had undergone ileal conduit with or without cystectomy. Questionnaires on quality of life, BPS/IC symptoms and pain were mailed to patients. Outcomes in the cystectomy and the non-cystectomy groups were compared with Fisher's exact test. Results. Ileal conduit without cystectomy was performed in 20 patients. Two underwent a subsequent cystectomy owing to persistent symptoms. Three patients underwent ileal conduit with concomitant primary cystectomy. Nineteen patients were alive at the time of the study and 15 returned the questionnaires. Twelve responders had been treated with ileal conduit and three had undergone primary cystectomy. The quality of life in both the cystectomy and the non-cystectomy groups was comparable with that in the general population. Seven patients in the non-cystectomy group were free of specific BPS/IC symptoms. The remaining five patients had minimal symptoms. Two cystectomy patients were free of symptoms, while one still suffered from severe symptoms. Eleven patients reported having no pain while four patients had visual analogue scale (VAS) scores between 2 and 9.5. Three patients experiencing pain belonged to the non-cystectomy group. There was no difference between the cystectomy group and the non-cystectomy group with regard to the proportion of patients who were symptom free. Conclusion. Ileal conduit without cystectomy may be an appropriate option when performing urinary diversion in BPS/IC patients.

Norus T; Fode M; Nordling J

2013-09-01

364

Stable isotopic composition of water vapor in the tropics  

Science.gov (United States)

Water vapor samples collected during tropical field experiments at Puerto Escondido, Mexico, near Kwajalein (KWAJEX), and near Key West, Florida (CAMEX 4), were analyzed for their stable isotope contents, 1H218O:1H216O and 2H1H16O:1H216O. Highest ?18O values approached isotopic equilibrium with seawater during quiescent weather or in regions of isolated or disorganized convection. Lowest ?18O values occurred in or downwind from regions of organized mesoscale weather disturbances and ranged as low as 15‰ below isotopic equilibrium with seawater. The mean ?18O value of vapor over the sea surface therefore decreases as storm activity and organization increases.

Lawrence, James Robert; Gedzelman, Stanley David; Dexheimer, Darielle; Cho, Hye-Khung; Carrie, Gordon D.; Gasparini, Robert; Anderson, Casey R.; Bowman, Kenneth P.; Biggerstaff, Mike I.

2004-03-01

365

Synthesis and characterization of WS2 nanoparticles by chemical vapor condensation.  

UK PubMed Central (United Kingdom)

Nano-sized WS2 based powders were synthesized by chemical vapor condensation (CVC) process using tungsten carbonyl (W(CO)6) as precursor and vaporized sulphur. Prior to WS2 nanopowders synthesis, pure tungsten nanopowders were produced by chemical vapor condensation to define the optimum synthesis parameters, which were then successfully applied to synthesize tungsten disulphide. The influence of experimental parameters on phase and chemical composition as well as mean size of the particles in order to produce pure tungsten and WS2 nanopowders was studied. Structure, phase composition and particles size of WS2 nanoparticles were precisely characterized by means of XRD, FESEM and TEM.

Lee DW; Tolochko OV; Turaev FR; Kim D; Kim BK

2010-01-01

366

Synthesis and characterization of WS2 nanoparticles by chemical vapor condensation.  

Science.gov (United States)

Nano-sized WS2 based powders were synthesized by chemical vapor condensation (CVC) process using tungsten carbonyl (W(CO)6) as precursor and vaporized sulphur. Prior to WS2 nanopowders synthesis, pure tungsten nanopowders were produced by chemical vapor condensation to define the optimum synthesis parameters, which were then successfully applied to synthesize tungsten disulphide. The influence of experimental parameters on phase and chemical composition as well as mean size of the particles in order to produce pure tungsten and WS2 nanopowders was studied. Structure, phase composition and particles size of WS2 nanoparticles were precisely characterized by means of XRD, FESEM and TEM. PMID:20352860

Lee, Dong-Won; Tolochko, O V; Turaev, Farkhod R; Kim, Dongsoo; Kim, Byoung-Kee

2010-01-01

367

Long-Term Regeneration and Functional Recovery of a 15?mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits.  

UK PubMed Central (United Kingdom)

Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15?mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.

Hsu SH; Chan SH; Weng CT; Yang SH; Jiang CF

2013-01-01

368

Fabrication of bioactive conduits containing the fibroblast growth factor 1 and neural stem cells for peripheral nerve regeneration across a 15 mm critical gap  

International Nuclear Information System (INIS)

Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan–nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve. (paper)

2013-01-01

369

Recovery of two-point discrimination function after digital nerve repair in the hand using resorbable FDA- and CE-approved nerve conduits.  

UK PubMed Central (United Kingdom)

This article aims to provide an overview of all clinical studies reporting sensory outcome as measured by two-point discrimination after digital nerve repair in the hand using resorbable Food and Drug Administration (FDA)- and CE-approved nerve conduits. The minimum follow-up for inclusion in this review was 11 months. In total, 235 nerve reconstructions could be classified. A total of 169 (72%) nerve reconstructions with a synthetic polyester-based nerve conduit were included; the other 66 nerves were reconstructed with collagen-based nerve conduits. To obtain the most reliable and comparable data, outcomes of each study were reclassified in the classification system as was used in the first two prospective randomised multicentre studies on the use of resorbable nerve conduits for repair of digital nerve gaps in the hand. Of the 235 nerve reconstructions, 171 (73%) nerve reconstructions showed good to excellent functional outcome. As many as 64 (27%) of the nerve reconstructions had a poor outcome. Based on the available data in this article at this moment, we conclude that digital nerve gaps up to 4 cm can be bridged by resorbable nerve conduits with a sensory outcome that can be qualified as good to excellent in almost 75% of cases after 11 months. Differences between FDA- and CE-approved nerve conduits could not be detected, apart from the rates of protrusion that were not observed using collagen-based nerve conduits.

Meek MF; Coert JH

2013-10-01

370

Acceleration of peripheral nerve regeneration using nerve conduits in combination with induced pluripotent stem cell technology and a basic fibroblast growth factor drug delivery system.  

Science.gov (United States)

Various modifications including addition of Schwann cells or incorporation of growth factors with bioabsorbable nerve conduits have been explored as options for peripheral nerve repair. However, no reports of nerve conduits containing both supportive cells and growth factors have been published as a regenerative therapy for peripheral nerves. In the present study, sciatic nerve gaps in mice were reconstructed in the following groups: nerve conduit alone (control group), nerve conduit coated with induced pluripotent stem cell (iPSc)-derived neurospheres (iPSc group), nerve conduit coated with iPSc-derived neurospheres and basic fibroblast growth factor (bFGF)-incorporated gelatin microspheres (iPSc + bFGF group), and autograft. The fastest functional recovery and the greatest axon regeneration occurred in the autograft group, followed in order by the iPSc + bFGF group, iPSc group, and control group until 12 weeks after reconstruction. Thus, peripheral nerve regeneration using nerve conduits and functional recovery in mice was accelerated by a combination of iPSc-derived neurospheres and a bFGF drug delivery system. The combination of all three fundamental methodologies, iPSc technology for supportive cells, bioabsorbable nerve conduits for scaffolds, and a bFGF drug delivery system for growth factors, was essential for peripheral nerve regenerative therapy. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23733515

Ikeda, Mikinori; Uemura, Takuya; Takamatsu, Kiyohito; Okada, Mitsuhiro; Kazuki, Kenichi; Tabata, Yasuhiko; Ikada, Yoshito; Nakamura, Hiroaki

2013-06-01

371

Acceleration of peripheral nerve regeneration using nerve conduits in combination with induced pluripotent stem cell technology and a basic fibroblast growth factor drug delivery system.  

UK PubMed Central (United Kingdom)

Various modifications including addition of Schwann cells or incorporation of growth factors with bioabsorbable nerve conduits have been explored as options for peripheral nerve repair. However, no reports of nerve conduits containing both supportive cells and growth factors have been published as a regenerative therapy for peripheral nerves. In the present study, sciatic nerve gaps in mice were reconstructed in the following groups: nerve conduit alone (control group), nerve conduit coated with induced pluripotent stem cell (iPSc)-derived neurospheres (iPSc group), nerve conduit coated with iPSc-derived neurospheres and basic fibroblast growth factor (bFGF)-incorporated gelatin microspheres (iPSc+bFGF group), and autograft. The fastest functional recovery and the greatest axon regeneration occurred in the autograft group, followed in order by the iPSc+bFGF group, iPSc group, and control group until 12 weeks after reconstruction. Thus, peripheral nerve regeneration using nerve conduits and functional recovery in mice was accelerated by a combination of iPSc-derived neurospheres and a bFGF drug delivery system. The combination of all three fundamental methodologies, iPSc technology for supportive cells, bioabsorbable nerve conduits for scaffolds, and a bFGF drug delivery system for growth factors, was essential for peripheral nerve regenerative therapy.

Ikeda M; Uemura T; Takamatsu K; Okada M; Kazuki K; Tabata Y; Ikada Y; Nakamura H

2013-06-01

372

Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits  

Science.gov (United States)

Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15?mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.

Hsu, Shan-hui; Chan, Shan-Ho; Weng, Chih-tsung; Yang, Shu-Hui; Jiang, Ching-Fen

2013-01-01

373

Long-Term Regeneration and Functional Recovery of a 15?mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits.  

Science.gov (United States)

Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15?mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits. PMID:24027599

Hsu, Shan-Hui; Chan, Shan-Ho; Weng, Chih-Tsung; Yang, Shu-Hui; Jiang, Ching-Fen

2013-08-21

374

Benzene vapor recovery and processing  

International Nuclear Information System (INIS)

[en] The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable m