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Sample records for expiratory resistor arterial

  1. Using an expiratory resistor, arterial pulse pressure variations predict fluid responsiveness during spontaneous breathing: an experimental porcine study.

    Science.gov (United States)

    Dahl, Michael K; Vistisen, Simon T; Koefoed-Nielsen, Jacob; Larsson, Anders

    2009-01-01

    Fluid responsiveness prediction is difficult in spontaneously breathing patients. Because the swings in intrathoracic pressure are minor during spontaneous breathing, dynamic parameters like pulse pressure variation (PPV) and systolic pressure variation (SPV) are usually small. We hypothesized that during spontaneous breathing, inspiratory and/or expiratory resistors could induce high arterial pressure variations at hypovolemia and low variations at normovolemia and hypervolemia. Furthermore, we hypothesized that SPV and PPV could predict fluid responsiveness under these conditions. Eight prone, anesthetized and spontaneously breathing pigs (20 to 25 kg) were subjected to a sequence of 30% hypovolemia, normovolemia, and 20% and 40% hypervolemia. At each volemic level, the pigs breathed in a randomized order either through an inspiratory and/or an expiratory threshold resistor (7.5 cmH2O) or only through the tracheal tube without any resistor. Hemodynamic and respiratory variables were measured during the breathing modes. Fluid responsiveness was defined as a 15% increase in stroke volume (DeltaSV) following fluid loading. Stroke volume was significantly lower at hypovolemia compared with normovolemia, but no differences were found between normovolemia and 20% or 40% hypervolemia. Compared with breathing through no resistor, SPV was magnified by all resistors at hypovolemia whereas there were no changes at normovolemia and hypervolemia. PPV was magnified by the inspiratory resistor and the combined inspiratory and expiratory resistor. Regression analysis of SPV or PPV versus DeltaSV showed the highest R2 (0.83 for SPV and 0.52 for PPV) when the expiratory resistor was applied. The corresponding sensitivity and specificity for prediction of fluid responsiveness were 100% and 100%, respectively, for SPV and 100% and 81%, respectively, for PPV. Inspiratory and/or expiratory threshold resistors magnified SPV and PPV in spontaneously breathing pigs during hypovolemia

  2. Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.

    Science.gov (United States)

    Fagevik Olsén, Monika; Carlsson, Maria; Olsén, Erik; Westerdahl, Elisabeth

    2015-10-01

    Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant. Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times. Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures. Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures. Copyright © 2015 by

  3. Predictors of response to a nasal expiratory resistor device and its potential mechanisms of action for treatment of obstructive sleep apnea.

    Science.gov (United States)

    Patel, Amit V; Hwang, Dennis; Masdeu, Maria J; Chen, Guo-Ming; Rapoport, David M; Ayappa, Indu

    2011-02-15

    A one-way nasal resistor has recently been shown to reduce sleep disordered breathing (SDB) in a subset of patients with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS). The purpose of this study was to examine characteristics predictive of therapeutic response to the device and provide pilot data as to its potential mechanisms of action. PATIENTS, INTERVENTIONS, AND MEASUREMENTS: 20 subjects (15M/5F, age 54 ± 12 years, BMI 33.5 ± 5.6 kg/m²) with OSAHS underwent 3 nocturnal polysomnograms (NPSG) including diagnostic, therapeutic (with a Provent® nasal valve device), and CPAP. Additional measurements included intranasal pressures and PCO₂, closing pressures (Pcrit), and awake lung volumes in different body positions. In 19/20 patients who slept with the device, RDI was significantly reduced with the nasal valve device compared to the diagnostic NPSG (27 ± 29/h vs 49 ± 28/h), with 50% of patients having an acceptable therapeutic response. Among demographic, lung volume, or diagnostic NPSG measures or markers of collapsibility, no significant predictors of therapeutic response were found. There was a suggestion that patients with position-dependent SDB (supine RDI > lateral RDI) were more likely to have an acceptable therapeutic response to the device. Successful elimination of SDB was associated with generation and maintenance of an elevated end expiratory pressure. No single definitive mechanism of action was elucidated. The present study shows that the nasal valve device can alter SDB across the full spectrum of SDB severity. There was a suggestion that subjects with positional or milder SDB in the lateral position were those most likely to respond.

  4. Resistor holder

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    A resistor device for use with electrostatic particle accelerators includes a resistor element positioned within a tubular housing having a fixed end cap at one end thereof and a movable end cap at the other end thereof. The tubular housing, fixed end cap, and movable end cap serve as an electromagnetic field for the resistor element. Conductive disks engage opposite ends of the resistor element and concentrically position the resistor element within the tubular housing. Helical springs engage the conductive disks and the end caps to yieldably support the movable end caps and resistor element for yieldable axial movement relative to the tubular housing. An annular conducting ring is secured to the tubular housing and is spaced radially from the movable end cap and cooperates with the latter to define an annular spark gap.

  5. COMBINED REDUCED FORCED EXPIRATORY VOLUME IN 1-SECOND (FEV1) AND PERIPHERAL ARTERY DISEASE IN SEDENTARY ELDERS WITH FUNCTIONAL LIMITATIONS

    Science.gov (United States)

    Vaz Fragoso, Carlos A.; Hsu, Fang-Chi; Brinkley, Tina; Church, Timothy; Liu, Christine K.; Manini, Todd; Newman, Anne B.; Stafford, Randall S.; McDermott, Mary M.; Gill, Thomas M.

    2014-01-01

    Objectives Because they are potentially modifiable and may coexist, we evaluated the combined occurrence of a reduced forced expiratory volume in 1-second (FEV1) and peripheral artery disease (PAD), including its association with exertional symptoms, physical inactivity, and impaired mobility, in sedentary elders with functional limitations. Design Cross-sectional. Setting Lifestyle Interventions and Independence in Elder (LIFE) Study. Participants 1307 sedentary community-dwelling persons, mean age 78.9, with functional limitations (Short Physical Performance Battery [SPPB] the San Diego Claudication Questionnaire. Physical inactivity was evaluated by percent of accelerometry wear-time with activity the 400MWT (gait-speed The two combined conditions were associated with exertional dyspnea (adjusted odds ratio [adjOR] 2.59 [1.20, 5.60]) and slow gait-speed (adjOR 3.15 [1.72, 5.75]) but not with exertional leg symptoms, high sedentary-time, and moderate-to-severe mobility impairment. Conclusions In sedentary community-dwelling elders with functional limitations, a reduced FEV1 and PAD frequently coexisted and, in combination, were strongly associated with exertional dyspnea and slow gait-speed (a frailty indicator that increases the risk of deleterious outcomes). PMID:24973990

  6. Low pulmonary artery flush perfusion pressure combined with high positive end-expiratory pressure reduces oedema formation in isolated porcine lungs

    International Nuclear Information System (INIS)

    Schumann, Stefan; Schließmann, Stephan J; Wagner, Giskard; Goebel, Ulrich; Priebe, Hans-Joachim; Guttmann, Josef; Kirschbaum, Andreas

    2010-01-01

    Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH 2 O) or high (8 cmH 2 O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p < 0.05) during perfusion at low PAP (62 ± 32% and 42 ± 26%, respectively) compared to perfusion at high PAP (133 ± 54% and 87 ± 30%, respectively). Compared to all other PAP–PEEP combinations, increases in lung weight were smallest (44 ± 9% and 27 ± 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p < 0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP–PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring

  7. Positive end expiratory pressure during one-lung ventilation: Selecting ideal patients and ventilator settings with the aim of improving arterial oxygenation

    Directory of Open Access Journals (Sweden)

    Hoftman Nir

    2011-01-01

    Full Text Available The efficacy of positive end-expiratory pressure (PEEP in treating intraoperative hypoxemia during one-lung ventilation (OLV remains in question given conflicting results of prior studies. This study aims to (1 evaluate the efficacy of PEEP during OLV, (2 assess the utility of preoperative predictors of response to PEEP, and (3 explore optimal intraoperative settings that would maximize the effects of PEEP on oxygenation. Forty-one thoracic surgery patients from a single tertiary care university center were prospectively enrolled in this observational study. After induction of general anesthesia, a double-lumen endotracheal tube was fiberoptically positioned and OLV initiated. Intraoperatively, PEEP = 5 and 10 cmH 2 O were sequentially applied to the ventilated lung during OLV. Arterial oxygenation, cardiovascular performance parameters, and proposed perioperative variables that could predict or enhance response to PEEP were analysed. T-test and c2 tests were utilized for continuous and categorical variables, respectively. Multivariate analyses were carried out using a classification tree model of binary recursive partitioning. PEEP improved arterial oxygenation by ≥20% in 29% of patients (n = 12 and failed to do so in 71% (n = 29; however, no cardiovascular impact was noted. Among the proposed clinical predictors, only intraoperative tidal volume per kilogram differed significantly between responders to PEEP and non-responders (mean 6.6 vs. 5.7 ml/kg, P = 0.013; no preoperative variable predicted response to PEEP. A multivariate analysis did not yield a clinically significant model for predicting PEEP responsiveness. PEEP improved oxygenation in a subset of patients; larger, although still protective tidal volumes favored a positive response to PEEP. No preoperative variables, however, could be identified as reliable predictors for PEEP responders.

  8. N-Bit Binary Resistor

    Science.gov (United States)

    Tcheng, Ping

    1989-01-01

    Binary resistors in series tailored to precise value of resistance. Desired value of resistance obtained by cutting appropriate traces across resistors. Multibit, binary-based, adjustable resistor with high resolution used in many applications where precise resistance required.

  9. Vamistor resistor investigation

    Science.gov (United States)

    1973-01-01

    Results are presented of the failure investigation conducted on resistors produced by the Vamistor Divison, Wagner Electric Corporation. This failure investigation included; failure analyses, chemical and metallurgical analyses, failure mechanism studies, seal leak analyses, and nondestructive stress tests. The data, information, conclusions, and recommendation can be helpful in assessing current usage of these resistors.

  10. Time-adjusted variable resistor

    Science.gov (United States)

    Heyser, R. C.

    1972-01-01

    Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate.

  11. Resistors Improve Ramp Linearity

    Science.gov (United States)

    Kleinberg, L. L.

    1982-01-01

    Simple modification to bootstrap ramp generator gives more linear output over longer sweep times. New circuit adds just two resistors, one of which is adjustable. Modification cancels nonlinearities due to variations in load on charging capacitor and due to changes in charging current as the voltage across capacitor increases.

  12. Babylonian Resistor Networks

    Science.gov (United States)

    Mungan, Carl E.; Lipscombe, Trevor C.

    2012-01-01

    The ancient Babylonians had an iterative technique for numerically approximating the values of square roots. Their method can be physically implemented using series and parallel resistor networks. A recursive formula for the equivalent resistance R[subscript eq] is developed and converted into a nonrecursive solution for circuits using…

  13. Temperature-controlled resistor

    Science.gov (United States)

    Perkins, T. G.

    1969-01-01

    Electrical resistance of a carbon-pile resistor is controlled by the compression or relaxation of a pile of carbon disks by a thermally actuated bimetallic spring. The concept is advantageous in that it is direct-acting, can cover a wide range of controllable characteristics, and can handle considerable power directly.

  14. Electrochemical characterization of liquid resistors

    International Nuclear Information System (INIS)

    Wilson, J.M.; Whiteley, R.V.

    1983-01-01

    During the first two years of operation of Sandia's Particle Beam Fusion Accelerator (PBFA I) the reliability of the CuSO 4 solution resistors in the Marx Generator Energy Storage System has been unsatisfactory. Resistor failure, which is characterized by a large increase in resistance, has been attributed to materials, production techniques, and operating parameters. The problems associated with materials and production techniques have been identified and solutions are proposed. Non-ideal operating parameters are shown to cause polarization of the cathode in the resistor. This initiates electrochemical reactions in the resistor. These reactions often lead to resistance changes and to eventual resistor failure

  15. Application to printed resistors

    International Nuclear Information System (INIS)

    Hachiyanagi, Yoshimi; Uraki, Hisatsugu; Sawamura, Masashi

    1989-01-01

    Most of printed circuit boards are made at present by etching copper foils which are laminated on insulating composite boards of paper/phenol resin or glass nonwoven fabric/epoxy rein. This is called subtractive process, and since this is a wet process, the problem of coping with the pollution due to etching solution, plating solution and others is involved. As the method of solving this problem, attention has been paid to the dry process which forms conductor patterns by screen printing using electro-conductive paste. For such resin substrates, generally polymer thick films (PTF) using thermosetting resin as the binder are used. Also the research on the formation of resistors, condensers and other parts by printing using the technology of cermet thick films (CTF) and PTF is active, and it is partially put in practical use. The problems are the deformation and deterioration of substrates, therefore, as the countermeasures, electron beam hardening type PTF has been studied, and various pastes have been developed. In this paper, electron beam hardening type printed resistors are reported. The features, resistance paste, and a number of the experiments on printed resistors are described. (K.I.)

  16. Improved switch-resistor packaging

    Science.gov (United States)

    Redmerski, R. E.

    1980-01-01

    Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

  17. Calculable resistors of coaxial design

    International Nuclear Information System (INIS)

    Kucera, J; Vollmer, E; Schurr, J; Bohacek, J

    2009-01-01

    1000 Ω and 1290.64 Ω coaxial resistors with calculable frequency dependence have been realized at PTB to be used in quantum Hall effect-based impedance measurements. In contradistinction to common designs of coaxial resistors, the design described in this paper makes it possible to remove the resistive element from the shield and to handle it without cutting the outer cylindrical shield of the resistor. Emphasis has been given to manufacturing technology and suppressing unwanted sources of frequency dependence. The adjustment accuracy is better than 10 µΩ Ω −1

  18. High voltage load resistor array

    Science.gov (United States)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  19. For current viewing resistor loads

    Science.gov (United States)

    Lyons, Gregory R [Tijeras, NM; Hass, Jay B [Lee's Summit, MO

    2011-04-19

    The invention comprises a terminal unit for a flat cable comprising a BNC-PCB connector having a pin for electrically contacting one or more conducting elements of a flat cable, and a current viewing resistor having an opening through which the pin extends and having a resistor face that abuts a connector face of the BNC-PCB connector, wherein the device is a terminal unit for the flat cable.

  20. Resistor cooling in a vacuum

    International Nuclear Information System (INIS)

    Crittenden, R.; Krider, J.

    1987-01-01

    This note describes thermal measurements which were done on a resistor operating both in air at one atmosphere pressure and in a vacuum of a few milliTorr. The motivation for this measurement was our interest in operating a BGO crystal-photomultiplier tube-base assembly in a vacuum, as a synchrotron radiation detector to tag electrons in the MT beam. We wished to determine what fraction of the total resistor power was dissipated by convection in air, in order to know whether there would be excessive heating of the detector assembly in a vacuum. 3 figs

  1. Dual design resistor for high voltage conditioning and transmission lines

    Science.gov (United States)

    Siggins, Timothy Lynn [Newport News, VA; Murray, Charles W [Hayes, VA; Walker, Richard L [Norfolk, VA

    2007-01-23

    A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

  2. Karakteristik Tcr Dan Vcr Resistor Pasta Resistor Pada Substrat Alumina Dengan Teknologi Film Tebal

    OpenAIRE

    Raden Arief Setyawan, ST., MT., Rhezananta Arya H., Ir. M. Julius St., MS

    2014-01-01

    Resistor merupakan komponen yang sangat berperan dalam rangkaian film tebal. Resistor berteknologi film tebal mempunyai karakteristik yang terdiri dari TCR (Temperature Coefficient of Resistance) dan VCR (Voltage Coefficient of Resistance). Dari alasan di atas maka perlu untuk mengetahui bagaimana pembuatan resistor film tebal dan mengetahui karakteristiknya.Penelitian ini menggunakan proses screen printing dalam pembuatan resistor yang kemudian melalui proses pengendapan (15 menit), drying (...

  3. Remote Experiments in Resistor Measurement

    Directory of Open Access Journals (Sweden)

    Popescu Viorel

    2009-10-01

    Full Text Available The paper describes blended learningapproach to teaching resistor measurement. It is basedon “Learning by Doing” paradigm: interacticesimulation, laboratory plants, real experimentsaccessed by Web Publishing Tools under LabVIEW.Studying and experimenting access is opened for 24hours a day, 7 days a week under Moodle bookingsystem.

  4. Pressure-Sensitive Resistor Material

    Science.gov (United States)

    Du Fresne, E. R.

    1986-01-01

    Low-conductivity particles in rubber offer wide dynamic range. Sensor consists of particles of relatively low conductivity embedded in rubber. Resistance of sensor decreases by about 100 times as pressure on it increases from zero to 0.8 MN/M to the second power. Resistor promising candidate as tactile sensor for robots and remote manipulators.

  5. Discrete/PWM Ballast-Resistor Controller

    Science.gov (United States)

    King, Roger J.

    1994-01-01

    Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.

  6. 30 CFR 77.801 - Grounding resistors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding resistors. 77.801 Section 77.801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH...-Voltage Distribution § 77.801 Grounding resistors. The grounding resistor, where required, shall be of the...

  7. Current limiting capability of diffused resistors

    International Nuclear Information System (INIS)

    Shedd, W.; Cappelli, J.

    1979-01-01

    An experimental evaluation of the current limiting capability of dielectrically isolated diffused resistors at transient ionizing dose rates up to 6*10 12 rads(Si)/sec is presented. Existing theoretical predictions of the transient response of diffused resistors are summarized and compared to the experimentally measured values. The test resistors used allow the effects of sheet resistance and geometry on the transient response to be determined. The experimental results show that typical dielectrically isolated diffused resistors maintain adequate current limiting capability for use in radiation hardened integrated circuits

  8. Reliability growth of thin film resistors contact

    Directory of Open Access Journals (Sweden)

    Lugin A. N.

    2010-10-01

    Full Text Available Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

  9. Thermal aspects of resistors embedded in dielectrics

    International Nuclear Information System (INIS)

    Caprari, R.S.

    1995-10-01

    This note presents a formula for estimating the temperature of a distributed resistor or resistor chain that is immersed in a dielectric medium, which in turn is surrounded by a heat reservoir. An example computation from an actual instrument in included. 6 refs

  10. Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD

    International Nuclear Information System (INIS)

    O'Donnell, C.R.; Bankier, A.A.; O'Donnell, D.H.; Loring, S.H.; Boiselle, P.M.

    2014-01-01

    Aim: To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT). Materials and methods: After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves. Results: Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10–50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3. Conclusion: COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse

  11. Critical exponents for diluted resistor networks.

    Science.gov (United States)

    Stenull, O; Janssen, H K; Oerding, K

    1999-05-01

    An approach by Stephen [Phys. Rev. B 17, 4444 (1978)] is used to investigate the critical properties of randomly diluted resistor networks near the percolation threshold by means of renormalized field theory. We reformulate an existing field theory by Harris and Lubensky [Phys. Rev. B 35, 6964 (1987)]. By a decomposition of the principal Feynman diagrams, we obtain diagrams which again can be interpreted as resistor networks. This interpretation provides for an alternative way of evaluating the Feynman diagrams for random resistor networks. We calculate the resistance crossover exponent phi up to second order in epsilon=6-d, where d is the spatial dimension. Our result phi=1+epsilon/42+4epsilon(2)/3087 verifies a previous calculation by Lubensky and Wang, which itself was based on the Potts-model formulation of the random resistor network.

  12. Thermal Characterization of the Overload Carbon Resistors

    Directory of Open Access Journals (Sweden)

    Ivana Kostić

    2013-01-01

    Full Text Available In many applications, the electronic component is not continuously but only intermittently overloaded (e.g., inrush current, short circuit, or discharging interference. With this paper, we provide insight into carbon resistors that have to hold out a rarely occurring transient overload. Using simple electrical circuit, the resistor is overheating with higher current than declared, and dissipation is observed by a thermal camera.

  13. On load resistor noise in preamplifiers for semiconductor detectors

    International Nuclear Information System (INIS)

    Baldin, S.A.; Bajramashvili, I.A.; Gubin, S.F.

    1975-01-01

    The main causes resulting in the deterioration of energy resolution in preamplifiers for semiconductor detectors (scd) with a resistor in the feedback circuit are discussed. A comparison of noise characteristics has been carried out of a number of high-resistance commercial and experimental resistors. The resistor noise dependence on the nature of drop of the resistor impedance active part in the region up to 100 Kc, as well as on the resistor spurious capacitance in shown

  14. Studying the noise parameters of thin-film silicon resistors

    International Nuclear Information System (INIS)

    Belogurov, S.V.; Gostilo, V.V.; Yurov, A.S.

    1986-01-01

    The results of studies on spectral density and energy noise equivalent of thin-film resistors on the base of amorphous silicon and KIM and KVM commercial high-ohmic resistors are presented. Dependence of the active part of impedance on frequency is shown to be the main source of redundant noise in resistors. Dependence of spectral density of noise voltage of current noises of silicon resistors on applied voltage is described by the formula S T =B V 2 /f 1.6 with the values B=(1.4-1.7)x10 -12 Hz 0.6 . As to noise parameters the silicon resistor is superior to commercial resistors

  15. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  16. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  17. Process for forming synapses in neural networks and resistor therefor

    Science.gov (United States)

    Fu, Chi Y.

    1996-01-01

    Customizable neural network in which one or more resistors form each synapse. All the resistors in the synaptic array are identical, thus simplifying the processing issues. Highly doped, amorphous silicon is used as the resistor material, to create extremely high resistances occupying very small spaces. Connected in series with each resistor in the array is at least one severable conductor whose uppermost layer has a lower reflectivity of laser energy than typical metal conductors at a desired laser wavelength.

  18. Physical Analysis of an Electric Resistor Heating

    Science.gov (United States)

    Perea Martins, J. E. M.

    2018-01-01

    This work describes a simple experiment to measure the resistor temperature as a function of the applied power and proves that it is an efficient way to introduce some important physical concepts in classroom, including the Joule's first law, hot-spot temperature, thermal resistance, thermal dissipation constant, time constant and the Newton's law…

  19. Physical analysis of an electric resistor heating

    Science.gov (United States)

    Perea Martins, J. E. M.

    2018-05-01

    This work describes a simple experiment to measure the resistor temperature as a function of the applied power and proves that it is an efficient way to introduce some important physical concepts in classroom, including the Joule’s first law, hot-spot temperature, thermal resistance, thermal dissipation constant, time constant and the Newton’s law of cooling.

  20. 30 CFR 75.801 - Grounding resistors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding resistors. 75.801 Section 75.801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.801 Grounding...

  1. Stochastic Resonance Induced by Dichotomous Resistor in an Electric Circuit

    International Nuclear Information System (INIS)

    Li Jinghui; Han Yinxia

    2007-01-01

    An electric circuit with dichotomous resistor is investigated. It is shown that the amplitude of the average electric current washing the resistor represents the phenomenon of stochastic resonance, which is the response as a function of the correlation time of the dichotomous resistor.

  2. 30 CFR 77.510 - Resistors; location and guarding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Resistors; location and guarding. 77.510 Section 77.510 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... COAL MINES Electrical Equipment-General § 77.510 Resistors; location and guarding. Resistors, heaters...

  3. Slew Rate Induced Distortion in Switched-Resistor Integrators

    NARCIS (Netherlands)

    Jiraseree-Amornkun, A.; Jiraseree-amornkun, A.; Worapishet, A.; Klumperink, Eric A.M.; Nauta, Bram; Surakampontorn, W.

    2006-01-01

    Abstract—OPAMP-RC integrators built with linear resistors and capacitors can achieve very high linearity. By means of a switched resistor, tuning of the RC time-constant is possible via the duty-cycle of the clock controlling the switched resistor. This paper analyzes the effect of OPAMP slew rate

  4. Rational and irrational numbers from unit resistors

    International Nuclear Information System (INIS)

    Kasperski, Maciej; Kłobus, Waldemar

    2014-01-01

    We address the problem of constructing a network of unit resistors such that it enables the retrieval of an arbitrary value of equivalent resistance. In particular, we employ the notion of continued fractions to construct a ladder network by which we can easily obtain any fractional value resistance. In addition, since any irrational number is associated with an infinite continued fraction, we discuss the convergence of the equivalent resistance of an infinite resistive ladder and various aspects concerning the approximations of arbitrary numbers attained by adding additional resistors successively to the network. The presented methods can be easily implemented in an educational laboratory and offer an interesting addition to the topic of Ohm’s law. (paper)

  5. Effects of surfaces on resistor percolation.

    Science.gov (United States)

    Stenull, O; Janssen, H K; Oerding, K

    2001-05-01

    We study the effects of surfaces on resistor percolation at the instance of a semi-infinite geometry. Particularly we are interested in the average resistance between two connected ports located on the surface. Based on general grounds as symmetries and relevance we introduce a field theoretic Hamiltonian for semi-infinite random resistor networks. We show that the surface contributes to the average resistance only in terms of corrections to scaling. These corrections are governed by surface resistance exponents. We carry out renormalization-group improved perturbation calculations for the special and the ordinary transition. We calculate the surface resistance exponents phiS and phiS(infinity) for the special and the ordinary transition, respectively, to one-loop order.

  6. Expiratory timing in obstructive sleep apnoeas.

    Science.gov (United States)

    Cibella, F; Marrone, O; Sanci, S; Bellia, V; Bonsignore, G

    1990-03-01

    Diaphragmatic electromyogram was recorded during NREM sleep in 4 patients affected by obstructive sleep apnoea (OSA) syndrome in order to evaluate the behaviour of expiratory time (TE) in the course of the obstructive apnoea-ventilation cycle. The two components of TE, i.e. time of post-inspiratory inspiratory activity (TPIIA) and time of expiratory phase 2 (TE2) were separately analysed. TPIIA showed a short duration, with only minor variations, within the apnoea, while its duration was more variable and longer in the interapnoeic periods: the longest TPIIA values were associated with the highest inspiratory volumes in the same breaths. This behaviour seemed regulated according to the need of a more or less effective expiratory flow braking, probably as a result of pulmonary stretch receptors discharge. Conversely TE2 showed a continuous gradual modulation, progressively increasing in the pre-apnoeic period, decreasing during the apnoea and increasing in the post-apnoeic period: these TE2 variations seemed related to oscillations in chemical drive. These data show that TE in the obstructive apnoea-ventilation cycle results from a different modulation in its two components and suggest that both mechanical and chemical influences play a role in its overall duration.

  7. Biphase sinusoidal oscillator based on negative resistor.

    Science.gov (United States)

    Bayard, Jean

    2010-06-01

    This paper describes a biphase sinusoidal generator which provides two signals: v(ref)=V(M) sin(omegat) and v(out)=V(M) sin(omegat+DeltaPhi), where DeltaPhi is in the range 0, pi/2 or -pi/2, 0 and is not dependent on the frequency value. It is based on a negative resistor and it requires very few components. SPICE simulations and measurements on an experimental setup confirm the theoretical analysis.

  8. Resistor Networks based on Symmetrical Polytopes

    Directory of Open Access Journals (Sweden)

    Jeremy Moody

    2015-03-01

    Full Text Available This paper shows how a method developed by Van Steenwijk can be generalized to calculate the resistance between any two vertices of a symmetrical polytope all of whose edges are identical resistors. The method is applied to a number of cases that have not been studied earlier such as the Archimedean polyhedra and their duals in three dimensions, the regular polytopes in four dimensions and the hypercube in any number of dimensions.

  9. Solid-state resistor for pulsed power machines

    Science.gov (United States)

    Stoltzfus, Brian; Savage, Mark E.; Hutsel, Brian Thomas; Fowler, William E.; MacRunnels, Keven Alan; Justus, David; Stygar, William A.

    2016-12-06

    A flexible solid-state resistor comprises a string of ceramic resistors that can be used to charge the capacitors of a linear transformer driver (LTD) used in a pulsed power machine. The solid-state resistor is able to absorb the energy of a switch prefire, thereby limiting LTD cavity damage, yet has a sufficiently low RC charge time to allow the capacitor to be recharged without disrupting the operation of the pulsed power machine.

  10. Adjustable thermal resistor by reversibly folding a graphene sheet.

    Science.gov (United States)

    Song, Qichen; An, Meng; Chen, Xiandong; Peng, Zhan; Zang, Jianfeng; Yang, Nuo

    2016-08-11

    Phononic (thermal) devices such as thermal diodes, thermal transistors, thermal logic gates, and thermal memories have been studied intensively. However, tunable thermal resistors have not been demonstrated yet. Here, we propose an instantaneously adjustable thermal resistor based on folded graphene. Through theoretical analysis and molecular dynamics simulations, we study the phonon-folding scattering effect and the dependence of thermal resistivity on the length between two folds and the overall length. Furthermore, we discuss the possibility of realizing instantaneously adjustable thermal resistors in experiment. Our studies bring new insights into designing thermal resistors and understanding the thermal modulation of 2D materials by adjusting basic structure parameters.

  11. Studies of tantalum nitride thin film resistors

    International Nuclear Information System (INIS)

    Langley, R.A.

    1975-01-01

    Backscattering of 2-MeV He ions was used to correlate the electrical properties of sputtered TaN/sub x/ thin-film resistors with their N content. The properties measured were sheet resistance, differential Seebeck potential (DSP), thermal coefficient of resistance (TCR), and stability. Resistivity and DSP are linearly dependent on N content for N/Ta ratios of 0.25 to 0.55. TCR decreases sharply below N/Ta = 0.35 and is relatively constant from 0.35 to 0.55. Stability is independent of N content. (DLC)

  12. Multifractal properties of resistor diode percolation.

    Science.gov (United States)

    Stenull, Olaf; Janssen, Hans-Karl

    2002-03-01

    Focusing on multifractal properties we investigate electric transport on random resistor diode networks at the phase transition between the nonpercolating and the directed percolating phase. Building on first principles such as symmetries and relevance we derive a field theoretic Hamiltonian. Based on this Hamiltonian we determine the multifractal moments of the current distribution that are governed by a family of critical exponents [psi(l)]. We calculate the family [psi(l)] to two-loop order in a diagrammatic perturbation calculation augmented by renormalization group methods.

  13. Resistor trimming geometry; past, present and future

    International Nuclear Information System (INIS)

    Alafogianni, M; Penlington, R; Birkett, M

    2016-01-01

    This paper explores the key developments in thin film resistive trimming geometry for use in the fabrication of discrete precision resistors. Firstly an introduction to the laser trimming process is given with respect to well established trim geometries such as the plunge, 'L' and serpentine cuts. The effect of these trim patterns on key electrical properties of resistance tolerance and temperature co-efficient of resistance (TCR) of the thin films is then discussed before the performance of more recent geometries such as the three-contact and random trim approaches are reviewed. In addition to the properties of the standard trim patterns, the concept of the heat affected zone (HAZ) and ablation energy and the effect of introducing a 'fine' trim in areas of low current density to improve device performance are also studied. It is shown how trimming geometry and laser parameters can be systematically controlled to produce thin film resistors of the required properties for varying applications such as high precision, long term stability and high power pulse performance

  14. Volumetric expiratory high-resolution CT of the lung

    International Nuclear Information System (INIS)

    Nishino, Mizuki; Hatabu, Hiroto

    2004-01-01

    We developed a volumetric expiratory high-resolution CT (HRCT) protocol that provides combined inspiratory and expiratory volumetric imaging of the lung without increasing radiation exposure, and conducted a preliminary feasibility assessment of this protocol to evaluate diffuse lung disease with small airway abnormalities. The volumetric expiratory high-resolution CT increased the detectability of the conducting airway to the areas of air trapping (P<0.0001), and added significant information about extent and distribution of air trapping (P<0.0001)

  15. Rancang Bangun Aplikasi Pendeteksi Tipe Dan Nilai Resistor Berbasis Android

    Directory of Open Access Journals (Sweden)

    I Putu Pratama Andika

    2015-11-01

    Full Text Available Android can be identified as the phone with the ability a high degree resembling computer, by making use of technological progress, an error in the determination of type and value of obstruction from resistors led a series of electronics result of the damage can be avoided, this is because of a resistor having the function of as parapet an electric current or as voltage divider of the series, detection so that the application of type and value of resistor able to contribute to the introduction of a resistor, by using processing tecnology digital image that is a method of hsv ( hue saturation value . Hsv useful as a limit of a color become a reference of the rings of color resistor, by applying this method application can do the introduction of against resistors diinputkan, to then give them the information relating to a type and value of a resistor. It has the percentage research success in the introduction of the value and type resistor by 57 %, to misidentified 30 % and not being recognized of 13 % .

  16. Variable thermal resistor based on self-powered Peltier effect

    OpenAIRE

    Min, Gao; Yatim, N. M.

    2008-01-01

    Heat flow through a thermoelectric material or device can be varied by an electrical resistor connected in parallel to it. This phenomenon is exploited to design a novel thermal component-variable thermal resistor. The theoretical background to this novel application is provided and an experimental result to demonstrate its feasibility is reported.

  17. Restrictions on modeling spin injection by resistor networks

    OpenAIRE

    Rashba, Emmanuel

    2008-01-01

    Because of the technical difficulties of solving spin transport equations in inhomogeneous systems, different resistor networks are widely applied for modeling spin transport. By comparing an analytical solution for spin injection across a ferromagnet - paramagnet junction with a resistor model approach, its essential limitations stemming from inhomogeneous spin populations are clarified.

  18. Variable thermal resistor based on self-powered Peltier effect

    International Nuclear Information System (INIS)

    Min Gao; Yatim, N Md

    2008-01-01

    Heat flow through a thermoelectric material or device can be varied by an electrical resistor connected in parallel to it. This phenomenon is exploited to design a novel thermal component-variable thermal resistor. The theoretical background to this novel application is provided and an experimental result to demonstrate its feasibility is reported. (fast track communication)

  19. Expiratory muscle control during vomiting - Role of brain stem expiratory neurons

    Science.gov (United States)

    Miller, A. D.; Tan, L. K.

    1987-01-01

    The neural mechanisms controlling the muscles involved during vomiting were examined using decerebrated cats. In one experiment, the activity of the ventral respiratory group (VRG) expiratory (E) neurons was recorded during induced 'fictive vomiting' (i.e., a series of bursts of coactivation of abdominal and phrenic nerves that would be expected to produce expulsion in unparalyzed animals) and vomiting. In a second, abdominal muscle electromyographic and nerve activity were compared before and after sectioning the axons of descending VRG E neurons as they cross the midline between C1 and the obex (the procedure that is known to abolish expiratory modulation of internal intercostal muscle activity). The results of the study indicate that the abdominal muscles are controlled differently during respiration and vomiting.

  20. Scaling in small-world resistor networks

    International Nuclear Information System (INIS)

    Korniss, G.; Hastings, M.B.; Bassler, K.E.; Berryman, M.J.; Kozma, B.; Abbott, D.

    2006-01-01

    We study the effective resistance of small-world resistor networks. Utilizing recent analytic results for the propagator of the Edwards-Wilkinson process on small-world networks, we obtain the asymptotic behavior of the disorder-averaged two-point resistance in the large system-size limit. We find that the small-world structure suppresses large network resistances: both the average resistance and its standard deviation approaches a finite value in the large system-size limit for any non-zero density of random links. We also consider a scenario where the link conductance decays as a power of the length of the random links, l -α . In this case we find that the average effective system resistance diverges for any non-zero value of α

  1. Ultrathin microwave metamaterial absorber utilizing embedded resistors

    Science.gov (United States)

    Kim, Young Ju; Hwang, Ji Sub; Yoo, Young Joon; Khuyen, Bui Xuan; Rhee, Joo Yull; Chen, Xianfeng; Lee, YoungPak

    2017-10-01

    We numerically and experimentally studied an ultrathin and broadband perfect absorber by enhancing the bandwidth with embedded resistors into the metamaterial structure, which is easy to fabricate in order to lower the Q-factor and by using multiple resonances with the patches of different sizes. We analyze the absorption mechanism in terms of the impedance matching with the free space and through the distribution of surface current at each resonance frequency. The magnetic field, induced by the antiparallel surface currents, is formed strongly in the direction opposite to the incident electromagnetic wave, to cancel the incident wave, leading to the perfect absorption. The corresponding experimental absorption was found to be higher than 97% in 0.88-3.15 GHz. The agreement between measurement and simulation was good. The aspects of our proposed structure can be applied to future electronic devices, for example, advanced noise-suppression sheets in the microwave regime.

  2. Peak Expiratory Flow Rate In Cigarette Smokers | Ukoli | Highland ...

    African Journals Online (AJOL)

    Objective: To compare lung function between smokers and non-smokers using Peak Expiratory Flow Rate (PEFR). Methods: This study examines the peak expiratory flow rate (PEFR) of three hundred and forty cigarette smokers, age and sex-matched with PEFR of equal number of non-smokers. Results: The mean PEFR of ...

  3. Effect of Training Frequency on Maximum Expiratory Pressure

    Science.gov (United States)

    Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

    2012-01-01

    Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

  4. Pinched hysteresis behavior in a PID-controlled resistor

    Directory of Open Access Journals (Sweden)

    M.A. Carrasco-Aguilar

    2018-06-01

    Full Text Available A current-controlled grounded resistor that exhibits a frequency-dependent pinched hysteresis loop is described. A mathematical model describing this behavior is derived and validated numerically, which has the form of a Proportional Integral-Derivative (PID controller. The proposed topology is build by using AD844 commercially available active device configured as second-generation current conveyor and experimental tests are compared with numerical simulations, showing a good agreement among them. Moreover, the proposed PID-controlled resistor can be reconfigured in order to be used in future applications such as programmable analog circuits. Keyword: Pinched hysteresis, Current conveyors, Nonlinear resistor, Proportional-Integral-Derivative Controller

  5. Studi Pengaruh Pengaman Galvanometer terhadap Keakuratan Hasil Pengukuran Resistor pada Jembatan Wheatstone Sederhana

    OpenAIRE

    Herlan, Dedeng

    2014-01-01

    Pengaman galvanometer pada penggunaan jembatan wheastone sebagai alat untuk mengukur besarkomponen resistor R dikembangkan pada penelitian ini. Pengaman galvanometer yang ditelitimemakai bahan resistor yang telah tersedia di pasaran dengan berbagai ukuran. . Berdasarkanbentuk strukturnya yang khas dari sebuah jembatan wheatstone, resistor yang digunakan sebagaipengaman galvanometer dalam penelitian ini, yaitu susunan resistor variabel R3 dan R4dengantipe L yang mengapit salah s...

  6. Transport behaviour of commercially available 100-Omega standard resistors

    CSIR Research Space (South Africa)

    Schumacher, B

    2001-04-01

    Full Text Available Several types of commercial 100-Omega resistors can be used with the cryogenic current comparator to maintain the resistance unit, derived from the Quantized Hall Effect (QHE), and to disseminate this unit to laboratory resistance standards. Up...

  7. NuMI proton kicker extraction magnet termination resistor system

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, S.R.; Jensen, C.C.; /Fermilab

    2005-05-01

    The temperature stability of the kicker magnet termination resistor assembly directly affects the field flatness and amplitude stability. Comprehensive thermal enhancements were made to the existing Main Injector resistor assembly design to satisfy NuMI performance specifications. Additionally, a fluid-processing system utilizing Fluorinert{reg_sign} FC-77 high-voltage dielectric was built to precisely control the setpoint temperature of the resistor assembly from 70 to 120F, required to maintain constant resistance during changing operational modes. The Fluorinert{reg_sign} must be continually processed to remove hazardous breakdown products caused by radiation exposure to prevent chemical attack of system components. Design details of the termination resistor assembly and Fluorinert{reg_sign} processing system are described. Early performance results will be presented.

  8. Novel charge sensitive preamplifier without high-value feedback resistor

    International Nuclear Information System (INIS)

    Xi Deming

    1992-01-01

    A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

  9. A resistor interpretation of general anisotropic cardiac tissue.

    Science.gov (United States)

    Shao, Hai; Sampson, Kevin J; Pormann, John B; Rose, Donald J; Henriquez, Craig S

    2004-02-01

    This paper describes a spatial discretization scheme for partial differential equation systems that contain anisotropic diffusion. The discretization method uses unstructured finite volumes, or the boxes, that are formed as a secondary geometric structure from an underlying triangular mesh. We show how the discretization can be interpreted as a resistive circuit network, where each resistor is assigned at each edge of the triangular element. The resistor is computed as an anisotropy dependent geometric quantity of the local mesh structure. Finally, we show that under certain conditions, the discretization gives rise to negative resistors that can produce non-physical hyperpolarizations near depolarizing stimuli. We discuss how the proper choice of triangulation (anisotropic Delaunay triangulation) can ensure monotonicity (i.e. all resistors are positive).

  10. Noise characteristics of resistors buried in low-temperature co-fired ceramics

    International Nuclear Information System (INIS)

    Kolek, A; Ptak, P; Dziedzic, A

    2003-01-01

    The comparison of noise properties of conventional thick film resistors prepared on alumina substrates and resistors embedded in low-temperature co-fired ceramics (LTCCs) is presented. Both types of resistors were prepared from commercially available resistive inks. Noise measurements of LTCC resistors below 1 kHz show Gaussian 1/f noise. This is concluded from the calculations of the second spectra as well as from studying the volume dependence of noise intensity. It has occurred that noise index of LTCC resistors on average is not worse than that of conventional resistors. A detailed study of co-fired surface resistors and co-fired buried resistors show that burying a resistor within LTCC substrate usually leads to (significant) enhancement of resistance but not of noise intensity. We interpret this behaviour as another argument in favour of tunnelling as the dominant conduction mechanism in LTCC resistors

  11. Free-standing silicon micro machined resistors from (110) substrate

    International Nuclear Information System (INIS)

    Bernardini, R.; Diligenti, A.; Nannini, A.; Piotto, M.

    1998-01-01

    A simple process to obtain silicon planes released from the substrate and provided with large area pads for ohmic contacts is described. Resistors 500 μm long with a 40 μm x 1 μm cross section were obtained. Resistance measurements showed that the current flows in a reduced cross section, probably owing to the presence of a superficial depletion layer. Preliminary magnetoresistance measurements are presented. Reduction of the resistor cross section can be obtained by thermal oxidation

  12. Room-temperature antiferromagnetic memory resistor.

    Science.gov (United States)

    Marti, X; Fina, I; Frontera, C; Liu, Jian; Wadley, P; He, Q; Paull, R J; Clarkson, J D; Kudrnovský, J; Turek, I; Kuneš, J; Yi, D; Chu, J-H; Nelson, C T; You, L; Arenholz, E; Salahuddin, S; Fontcuberta, J; Jungwirth, T; Ramesh, R

    2014-04-01

    The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.

  13. Irreversible entropy model for damage diagnosis in resistors

    Energy Technology Data Exchange (ETDEWEB)

    Cuadras, Angel, E-mail: angel.cuadras@upc.edu; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos [Instrumentation, Sensor and Interfaces Group, Electronic Engineering Department, Escola d' Enginyeria de Telecomunicació i Aeronàutica de Castelldefels EETAC, Universitat Politècnica de Catalunya, Barcelona Tech (UPC), Castelldefels-Barcelona (Spain)

    2015-10-28

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

  14. Irreversible entropy model for damage diagnosis in resistors

    International Nuclear Information System (INIS)

    Cuadras, Angel; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos

    2015-01-01

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance

  15. Improvement of Transient Stability of Power System by System Damping Series Resistor (SDSR)

    OpenAIRE

    上里, 勝実; 千住, 智信; 当銘, 秀之; 高原, 景滋; Uezato, Katsumi; Senjyu, Tomonobu; Toume, Hideyuki; Takahara, Keiji

    1990-01-01

    The system damping resistor is one of the method for improving the transient stability of power systems. The main circuit is the simple construction so that is low cost and is few abnormal surge, and is superior in ability of economy, reliability and maintenance. Conventionally, most of all system damping resistors have adopted the paralleled resistor, whereas the series resistor is used little.In this paper, we investigate the characteristics of the series resistor by comparing with the para...

  16. Multi-detector CT evaluation in patients suspected of tracheobronchomalacia: Comparison of end-expiratory with dynamic expiratory volumetric acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, Gilbert R. [Department of Radiology (France)], E-mail: gferretti@chu-grenoble.fr; Jankowski, Adrien [Department of Radiology (France)], E-mail: ajankowski@chu-grenoble.fr; Perrin, Marie Amelie [Department of Radiology (France)], E-mail: maperrin@chu-grenoble.fr; Chouri, Nathalie [Department of Respiratory Diseases (France)], E-mail: nchouri@chu-grenoble.fr; Arnol, Nathalie [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: narnold@chu-grenoble.fr; Aubaud, Laurent [Department of Radiology (France)], E-mail: laubaud@chu-grenoble.fr; Pepin, Jean-Louis [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: jlpepin@chu-grenoble.fr

    2008-11-15

    Purpose: The aim of this study was to compare dynamic expiratory imaging and end-expiratory imaging using multi-detector CT (MDCT) of the central airways in patients suspected of tracheobronchomalacia (TBM). Methods: This study had local ethical committee approval. Seventy patients suspected of TBM were prospectively included. All patients underwent evaluation of central airways by three different low-dose MDCT acquisitions: end inspiration, end expiration, and dynamic expiration. Degree of airway collapse was measured by calculating the percentage change in the area and diameter of the airways between inspiratory and the two expiratory techniques at three levels of the trachea and in the sagittal diameter of the right and left main bronchi. Three threshold levels of percentage reduction in diameter or area (30%, 50%, and 70%) for defining TBM were evaluated. Results: In the entire population, the mean percentage of airway collapse was significantly greater with dynamic expiratory imaging than with the end-expiratory imaging at three different levels: lower thoracic trachea (26% vs. 16.6%, p < 0.009), right (25.2% vs. 14%, p < 0.01) and left main (24.7% vs. 13.3%, p < 0.01) bronchus. Whatever the threshold value for defining TBM, dynamic expiratory imaging always resulted in diagnosing TBM in more patients than end-expiratory imaging. Conclusions: Dynamic expiratory imaging shows a significantly greater degree and a significantly greater extent of airway collapse than standard end-expiratory imaging in patients suspected of TBM. Further evaluation of the clinical relevance of such findings is warranted.

  17. What's in a name? Expiratory tracheal narrowing in adults explained

    International Nuclear Information System (INIS)

    Leong, P.; Bardin, P.G.; Lau, K.K.

    2013-01-01

    Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions

  18. Short-term effects of positive expiratory airway pressure in patients being weaned from mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Marcelo de Mello Rieder

    2009-05-01

    Full Text Available OBJECTIVE: To investigate the feasibility and the cardiorespiratory effects of using positive expiratory airway pressure, a physiotherapeutic tool, in comparison with a T-tube, to wean patients from mechanical ventilation. METHODS/DESIGN: A prospective, randomized, cross-over study. SETTING: Two intensive care units. PATIENTS AND INTERVENTIONS: We evaluated forty patients who met weaning criteria and had been mechanically-ventilated for more than 48 hours, mean age 59 years, including 23 males. All patients were submitted to the T-tube and Expiratory Positive Airway Pressure devices, at 7 cm H2O, during a 30-minute period. Cardiorespiratory variables including work of breathing, respiratory rate (rr, peripheral oxygen saturation (SpO2, heart rate (hr, systolic, diastolic and mean arterial pressures (SAP, DAP, MAP were measured in the first and thirtieth minutes. The condition was analyzed as an entire sample set (n=40 and was also divided into subconditions: chronic obstructive pulmonary disease (n=14 and non-chronic obstructive pulmonary disease (non- chronic obstructive pulmonary disease (n=26 categories. Comparisons were made using a t-test and Analysis of Variance. The level of significance was p < 0.05. RESULTS: Our data showed an increase in work of breathing in the first and thirtieth minutes in the EPAP condition (0.86+ 0.43 and 1.02+1.3 as compared with the T-tube condition (0.25+0.26 and 0.26+0.35 (p<0.05, verified by the flow-sensor monitor (values in J/L. No statistical differences were observed when comparing the Expiratory Positive Airway Pressure and T-tube conditions with regard to cardiorespiratory measurements. The same result was observed for both chronic obstructive pulmonary disease and non- chronic obstructive pulmonary disease subconditions. CONCLUSIONS: Our study demonstrated that, in weaning patients from mechanical ventilation, the use of a fixed level of Expiratory Positive Airway Pressure caused an increase in work of

  19. The Sponge Resistor Model--A Hydrodynamic Analog to Illustrate Ohm's Law, the Resistor Equation R=?l/A, and Resistors in Series and Parallel

    Science.gov (United States)

    Pfister, Hans

    2014-01-01

    Physics students encountering electric circuits for the first time often ask why adding more resistors to a circuit sometimes increases and sometimes decreases the resulting total resistance. It appears that these students have an inadequate understanding of current flow and resistance. Students who do not adopt a model of current, voltage, and…

  20. A controllable resistor and its applications in pole-zero tracking frequency compensation methods for LDOs

    International Nuclear Information System (INIS)

    Wang Yi; He Lenian; Ning Zhihua; Shao Yali

    2009-01-01

    This paper presents a controllable resistor, which is formed by a MOS-resistor working in the deep triangle region and an auxiliary circuit. The auxiliary circuit can generate the gate-source voltage which is proportional to the output current of an low dropout regulator for the MOS-resistor. Thus, the equivalent output resistance of the MOS-resistor is inversely proportional to the output current, which is a suitable feature for pole-zero tracking frequency compensation methods. By switching the type of the MOS-resistor and current direction through the auxiliary circuit, the controllable resistor can be suitable for different applications. Three pole-zero tracking frequency compensation methods based on a single Miller capacitor with nulling resistor, unit-gain compensation cell and pseudo-ESR (equivalent serial resistor of load capacitor) power stage have been realized by this controllable resistor. Their advantages and limitations are discussed and verified by simulation results.

  1. A controllable resistor and its applications in pole-zero tracking frequency compensation methods for LDOs

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yi; He Lenian; Ning Zhihua; Shao Yali, E-mail: wangyi@vlsi.zju.edu.c [Institute of VLSI Design, Zhejiang University, Hangzhou 310027 (China)

    2009-09-15

    This paper presents a controllable resistor, which is formed by a MOS-resistor working in the deep triangle region and an auxiliary circuit. The auxiliary circuit can generate the gate-source voltage which is proportional to the output current of an low dropout regulator for the MOS-resistor. Thus, the equivalent output resistance of the MOS-resistor is inversely proportional to the output current, which is a suitable feature for pole-zero tracking frequency compensation methods. By switching the type of the MOS-resistor and current direction through the auxiliary circuit, the controllable resistor can be suitable for different applications. Three pole-zero tracking frequency compensation methods based on a single Miller capacitor with nulling resistor, unit-gain compensation cell and pseudo-ESR (equivalent serial resistor of load capacitor) power stage have been realized by this controllable resistor. Their advantages and limitations are discussed and verified by simulation results.

  2. Superoxide dismutase levels and peak expiratory flow in asthmatic children

    Directory of Open Access Journals (Sweden)

    Arie Kurniasih

    2016-11-01

    Full Text Available Background Asthma is a chronic inflammatory process which involve variety of cells such as inflammatory mediators, reactive oxygen species (ROS, and cytokines. The inflammatory process would be exacerbated in the presence of oxidative stress. Superoxide dismutase (SOD is the first important enzyme to protect the respiratory tract against oxidative stress. The decreased of SOD has a correlation with increased of airway obstruction and bronchospasm. Objective To assess for a correlation between superoxide dismutase (SOD levels and peak expiratory flow, as well as to determine the impact of SOD levels for predicting asthma attacks. Methods We conducted a prospective cohort study at Dr. Sardjito Hospital, Yogyakarta, between February and April 2011 involving asthmatic children aged 5-18 years. Subjects’ serum SOD levels and peak expiratory flow were measured at the same time point. We then performed a prospective study following up on the same subjects to find out if they had a recurrent asthma attack within one month of the tests. We also reassessed their peak expiratory flow one month after blood specimens were obtained. Results Thirty-nine patients were enrolled in this study. There was no significant correlation between SOD level and peak expiratory flow [r=0.289; 95%CI -0.025 to 0.47; P=0.074]. However, older age was significantly associated with higher peak expiratory flow (=0.5; 95%CI 3.10 to 11.57; P=0.01. Lower levels of SOD increased the risk of asthma attacks in a month following the initial measurements (RR=5.5; 95%CI 1.6 to 18.9; P=0.009. Conclusion Superoxide dismutase (SOD level is not significantly associated with peak expiratory flow. However, we find a relationship between older age and higher peak expiratory flow and a relationship between lower SOD levels and risk of asthma attacks within one month following the tests.

  3. Physiological techniques for detecting expiratory flow limitation during tidal breathing

    Directory of Open Access Journals (Sweden)

    N.G. Koulouris

    2011-09-01

    Full Text Available Patients with severe chronic obstructive pulmonary disease (COPD often exhale along the same flow–volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT. Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage, in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

  4. TI--CR--AL--O thin film resistors

    Science.gov (United States)

    Jankowski, Alan F.; Schmid, Anthony P.

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  5. Surface scattering mechanisms of tantalum nitride thin film resistor.

    Science.gov (United States)

    Chen, Huey-Ru; Chen, Ying-Chung; Chang, Ting-Chang; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chu, Tian-Jian; Shih, Chih-Cheng; Chuang, Nai-Chuan; Wang, Kao-Yuan

    2014-01-01

    In this letter, we utilize an electrical analysis method to develop a TaN thin film resistor with a stricter spec and near-zero temperature coefficient of resistance (TCR) for car-used electronic applications. Simultaneously, we also propose a physical mechanism mode to explain the origin of near-zero TCR for the TaN thin film resistor (TFR). Through current fitting, the carrier conduction mechanism of the TaN TFR changes from hopping to surface scattering and finally to ohmic conduction for different TaN TFRs with different TaN microstructures. Experimental data of current-voltage measurement under successive increasing temperature confirm the conduction mechanism transition. A model of TaN grain boundary isolation ability is eventually proposed to influence the carrier transport in the TaN thin film resistor, which causes different current conduction mechanisms.

  6. Scaling law of resistance fluctuations in stationary random resistor networks

    Science.gov (United States)

    Pennetta; Trefan; Reggiani

    2000-12-11

    In a random resistor network we consider the simultaneous evolution of two competing random processes consisting in breaking and recovering the elementary resistors with probabilities W(D) and W(R). The condition W(R)>W(D)/(1+W(D)) leads to a stationary state, while in the opposite case, the broken resistor fraction reaches the percolation threshold p(c). We study the resistance noise of this system under stationary conditions by Monte Carlo simulations. The variance of resistance fluctuations is found to follow a scaling law |p-p(c)|(-kappa(0)) with kappa(0) = 5.5. The proposed model relates quantitatively the defectiveness of a disordered media with its electrical and excess-noise characteristics.

  7. Comparison of changes in tidal volume associated with expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation

    OpenAIRE

    Morino, Akira; Shida, Masahiro; Tanaka, Masashi; Sato, Kimihiro; Seko, Toshiaki; Ito, Shunsuke; Ogawa, Shunichi; Takahashi, Naoaki

    2015-01-01

    [Purpose] This study was designed to compare and clarify the relationship between expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation, with a focus on tidal volume. [Subjects and Methods] The subjects were 18 patients on prolonged mechanical ventilation, who had undergone tracheostomy. Each patient received expiratory rib cage compression and expiratory abdominal compression; the order of implementation was randomized. Subjects ...

  8. Ruthenium oxide resistors as sensitive elements of composite bolometers

    International Nuclear Information System (INIS)

    Benassai, M.; Gallinaro, G.; Gatti, F.; Siri, S.; Vitale, S.

    1988-01-01

    Bolometers for particle detection made with Ruthenium oxide thermistors could be produced by means of a simple technique on a variety of different materials as substrata. Preliminary results on alpha particle detection with devices realized using commercial RuO 2 thick film resistor (Tfr) are considered positive for devices operating between. 3 and .1 k and determined us to pursue further the idea. Ruthenium oxide resistors on sapphire at the moment are being prepared. The behaviour of these devices st temperatures lower than .1 k has to be investigated in more detail

  9. A dc carpet cloak based on resistor networks.

    Science.gov (United States)

    Mei, Zhong Lei; Liu, Yu Sha; Yang, Fan; Cui, Tie Jun

    2012-11-05

    We propose, design, and implement a two-dimensional dc carpet cloak for steady electric field using the transformation optics (TO) method. Based on the circuit theory, we introduce a resistor network to mimic the resulting anisotropic conducting medium. The experimental prototype is fabricated using metal film resistors, and the measured results agree perfectly well with theoretical predictions. This study gives the first experimental verification of a dc carpet cloak, which expands the application of TO theory, and has potential applications in related areas.

  10. Electrochemical Migration on Electronic Chip Resistors in Chloride Environments

    DEFF Research Database (Denmark)

    Minzari, Daniel; Jellesen, Morten Stendahl; Møller, Per

    2009-01-01

    Electrochemical migration behavior of end terminals on ceramic chip resistors (CCRs) was studied using a novel experimental setup in varying sodium chloride concentrations from 0 to 1000 ppm. The chip resistor used for the investigation was 10-kΩ CCR size 0805 with end terminals made of 97Sn3Pb...... rate of the Sn and stability of Sn ions in the solution layer play a significant role in the formation of dendrites, which is controlled by chloride concentration and potential bias. Morphology, composition, and resistance of the dendrites were dependent on chloride concentration and potential....

  11. Comparison of changes in tidal volume associated with expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation.

    Science.gov (United States)

    Morino, Akira; Shida, Masahiro; Tanaka, Masashi; Sato, Kimihiro; Seko, Toshiaki; Ito, Shunsuke; Ogawa, Shunichi; Takahashi, Naoaki

    2015-07-01

    [Purpose] This study was designed to compare and clarify the relationship between expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation, with a focus on tidal volume. [Subjects and Methods] The subjects were 18 patients on prolonged mechanical ventilation, who had undergone tracheostomy. Each patient received expiratory rib cage compression and expiratory abdominal compression; the order of implementation was randomized. Subjects were positioned in a 30° lateral recumbent position, and a 2-kgf compression was applied. For expiratory rib cage compression, the rib cage was compressed unilaterally; for expiratory abdominal compression, the area directly above the navel was compressed. Tidal volume values were the actual measured values divided by body weight. [Results] Tidal volume values were as follows: at rest, 7.2 ± 1.7 mL/kg; during expiratory rib cage compression, 8.3 ± 2.1 mL/kg; during expiratory abdominal compression, 9.1 ± 2.2 mL/kg. There was a significant difference between the tidal volume during expiratory abdominal compression and that at rest. The tidal volume in expiratory rib cage compression was strongly correlated with that in expiratory abdominal compression. [Conclusion] These results indicate that expiratory abdominal compression may be an effective alternative to the manual breathing assist procedure.

  12. Inspiratory and expiratory HRCT findings in healthy smokers' lung

    International Nuclear Information System (INIS)

    Park, Hyeon Seon; Kwak, Byung Kook; Choi, Chi Hoon; Yang, Keun Mung; Lee, Chang Joon; Joo, Dong Il; Kim, Yang Soo

    1998-01-01

    The purpose of this study is to evaluate the lung changes in healthy smokers, as seen on inspiratory and expiratory high-resolution computed tomography (HRCT). Twenty-seven healthy smokers (light smokers, below 20 pack-years, n=16; heavy smokers, above 20 pack-years, n=11) and 25 nonsmokers underwent inspiratory and expiratory HRCT. All healthy smokers had normal pulmonary function and chest radiography. Parenchymal and subpleural micronodules, ground-glass attenuation, centrilobular and paraseptal emphysema, bronchial wall thickening, bronchiectasis and septal line were evaluated on inspiratory scan and by air-trapping on expiratory scan. According to the findings of HRCT, heavy smokers and higher frequency of parenchymal micronodules, ground-glass attenuation, centrilobular and paraseptal emphysema, and air-trapping than nonsmokers and light smokers. (author). 13 refs., 1 tab., 4 figs

  13. Lung function in North American Indian children: reference standards for spirometry, maximal expiratory flow volume curves, and peak expiratory flow.

    Science.gov (United States)

    Wall, M A; Olson, D; Bonn, B A; Creelman, T; Buist, A S

    1982-02-01

    Reference standards of lung function was determined in 176 healthy North American Indian children (94 girls, 82 boys) 7 to 18 yr of age. Spirometry, maximal expiratory flow volume curves, and peak expiratory flow rate were measured using techniques and equipment recommended by the American Thoracic Society. Standing height was found to be an accurate predictor of lung function, and prediction equations for each lung function variable are presented using standing height as the independent variable. Lung volumes and expiratory flow rates in North American Indian children were similar to those previously reported for white and Mexican-American children but were greater than those in black children. In both boys and girls, lung function increased in a curvilinear fashion. Volume-adjusted maximal expiratory flow rates after expiring 50 or 75% of FVC tended to decrease in both sexes as age and height increased. Our maximal expiratory flow volume curve data suggest that as North American Indian children grow, lung volume increases at a slightly faster rate than airway size does.

  14. Effects of positive end-expiratory pressure on arthroscopic shoulder surgery under general anesthesia.

    Science.gov (United States)

    Ersoy, Ayşın; Çakırgöz, Mensure; Ervatan, Zekeriya; Kıran, Özlem; Türkmen, Aygen; Esenyel, Cem Zeki

    2016-01-01

    Our study is a prospective, randomized study on patients undergoing arthroscopic shoulder surgery in the beach-chair position to evaluate the effects of positive end-expiratory pressure (PEEP) on hemodynamic stability, providing a bloodless surgical field and surgical satisfaction. Fifty patients were divided into two groups. Group I (n=25) had zero end-expiratory pressure (ZEEP) administered under general anesthesia, and group II (n=25) had +5 PEEP administered. During surgery, intraarticular hemorrhage and surgical satisfaction were evaluated on a scale of 0-10. During surgery, at the 5th, 30th, 60th, and 90th minutes and at the end of surgery, heart rate, mean arterial pressure (MAP), and positive inspiratory pressure were recorded. At the end of the surgery, the amount of bleeding and duration of the operation were recorded. In group I, the duration of operation and amount of bleeding were found to be significantly greater than those in group II (pshoulder surgery in the beach-chair position reduces the amount of hemorrhage in the surgical field and thus increases surgical satisfaction without requiring the creation of controlled hypotension.

  15. Switching phase states in two van der Pol oscillators coupled by ttochastically time-varying resistor

    OpenAIRE

    Uwate, Y; Nishio, Y; Stoop, R

    2009-01-01

    We explore the synchronization and switching behavior of a system of two identical van der Pol oscillators coupled by a stochastically timevarying resistor. Triggered by the time-varying resistor, the system of oscillators switches between synchronized and anti-synchronized behavior. We find that the preference of the synchronized/antisynchronized state is determined by the ratio of the probabilities of the two resistor states. The length of the phases of maintained resistor states, however, ...

  16. Frequency dependence of the active impedance component of silicon thin-film resistors

    International Nuclear Information System (INIS)

    Belogurov, S.V.; Gostilo, V.V.; Yurov, A.S.

    1987-01-01

    A high-resistant resistor on the silicon thin-film substrate considerably superior in noise and frequency performance than commercial resistors is described. The frequency dependence of the active impedance component is tested for determining noise and frequency dependences of silicon thin-film resistors. The obtained results permit to calculate the energy equivalent of resistor noise in nuclear radiation detection units at any temperature according to its frequency characteristic at room temperature

  17. Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation.

    Science.gov (United States)

    Spadaro, Savino; Grasso, Salvatore; Karbing, Dan Stieper; Fogagnolo, Alberto; Contoli, Marco; Bollini, Giacomo; Ragazzi, Riccardo; Cinnella, Gilda; Verri, Marco; Cavallesco, Narciso Giorgio; Rees, Stephen Edward; Volta, Carlo Alberto

    2018-03-01

    Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation. Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements. During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

  18. Continuously forced ballast resistor model for superconducting hot spots

    International Nuclear Information System (INIS)

    Ausloos, M.

    1981-01-01

    To neglect the Thomson effect in the ballast resistor theory is an incorrect assumption since it measures the velocity of the thermal grain boundaries. Due to the constant rate of heating or cooling, large oscillations are predicted in dR/dT near Tsub(c). (orig.)

  19. Resistor Extends Life Of Battery In Clocked CMOS Circuit

    Science.gov (United States)

    Wells, George H., Jr.

    1991-01-01

    Addition of fixed resistor between battery and clocked complementary metal oxide/semiconductor (CMOS) circuit reduces current drawn from battery. Basic idea to minimize current drawn from battery by operating CMOS circuit at lowest possible current consistent with use of simple, fixed off-the-shelf components. Prolongs lives of batteries in such low-power CMOS circuits as watches and calculators.

  20. Air-cooled fast discharge resistors for ITER magnets

    International Nuclear Information System (INIS)

    Tanchuk, Victor; Grigoriev, Sergey; Lokiev, Vladimir; Roshal, Alexander; Song, Inho; Buzykin, Oleg

    2011-01-01

    The ITER superconducting magnets will store up to 50 GJ of magnetic energy per operation cycle. In case of coil quench the energy stored in the coils must be extracted rapidly with a time constant from 7.5 to 14 s. It will be achieved by fast discharge resistors (FDR) normally bridged by circuit breakers and inserted in series with the superconducting coils. The fast discharge of the coils results practically in adiabatic heating of the resistive elements up to 200-300 deg. C. The resistors need to be cooled to the initial temperature over 6-8 h. Natural air circulation is proposed as a cooling method. In order to simulate the temperature response of the resistors to energy released in the resistive plates and to demonstrate their cooling capability within the required time by natural air circulation the numerical model of the resistor cooling circuit has been developed. As the calculations have shown, the developed FDR cooling system based on cooling by natural air circulation is capable of providing the required temperature operation regime of FDRs, but the supply channels are to be optimized so that the cooling time does not exceed the permissible one.

  1. SPICE Modeling of Body Bias Effect in 4H-SiC Integrated Circuit Resistors

    Science.gov (United States)

    Neudeck, Philip G.

    2017-01-01

    The DC electrical behavior of n-type 4H-SiC resistors used for realizing 500C durable integrated circuits (ICs) is studied as a function of substrate bias and temperature. Improved fidelity electrical simulation is described using SPICE NMOS model to simulate resistor substrate body bias effect that is absent from the SPICE semiconductor resistor model.

  2. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be...

  3. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless protection...

  4. 30 CFR 77.801-1 - Grounding resistors; continuous current rating.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding resistors; continuous current rating... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.801-1 Grounding resistors; continuous current rating. The ground fault current rating of grounding resistors shall meet the “extended...

  5. 30 CFR 77.901-1 - Grounding resistor; continuous current rating.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... resistor; continuous current rating. The ground fault current rating of grounding resistors shall meet the...

  6. Positive expiratory pressure - Common clinical applications and physiological effects.

    Science.gov (United States)

    Fagevik Olsén, Monika; Lannefors, Louise; Westerdahl, Elisabeth

    2015-03-01

    Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of devices can be used to create the resistance giving the increased expiratory pressure. Effects on pulmonary outcomes have been discussed in several publications, but the expected underlying physiology of the effect is seldom discussed. The aim of this article is to describe the purpose, performance, clinical application and underlying physiology of PEP when it is used to increase lung volumes, decrease hyperinflation or improve airway clearance. In clinical practice, the instruction how to use an expiratory resistance is of major importance since it varies. Different breathing patterns during PEP increase or reduce expiratory flow, result in movement of EPP centrally or peripherally and can increase or decrease lung volume. It is therefore necessary to give the right instructions to obtain the desired effects. As the different PEP techniques are being used by diverse patient groups it is not possible to give standard instructions. Based on the information given in this article the instructions have to be adjusted to give the optimal effect. There is no consensus regarding optimal treatment frequency and number of cycles included in each treatment session and must also be individualized. In future research, more precise descriptions are needed about physiological aims and specific instructions of how the treatments have been performed to assure as good treatment quality as possible and to be able to evaluate and compare treatment effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. predicted peak expiratory flow in human and the clinical implication ...

    African Journals Online (AJOL)

    DR. AMINU

    predicted PEF varied widely across formulae and choice of a particular formula may alter guideline- base care. This work has therefore accepted a recently published population-base equation proposed as the reference standard for future asthma guidelines. Keywords: Peak expiratory flow, Asthma, Practice guidelines, ...

  8. Knowledge, attitude and practice of nurses toward peak expiratory ...

    African Journals Online (AJOL)

    Background: Peak expiratory flow meter (PEFM) is an easy to use, relatively cheap device that can be used for guiding management of bronchial asthma by the patients at home according to a preset plan by health care workers. Objective: The aim of the study is to reveal the extent of knowledge and perception of nurses ...

  9. Factors influencing peak expiratory flow in teenage boys | van ...

    African Journals Online (AJOL)

    Background. Peak expiratory flow (PEF) is a useful measure of pulmonary health status and is frequently utilised in asthm, management. Reduction in PEF is usually indicative of onset (of asthma symptoms. However, use can be made of PEF values only if normal values are known. The definition of normal range is always ...

  10. Effects of nasal positive expiratory pressure on dynamic hyperinflation and 6-minute walk test in patients with COPD.

    Science.gov (United States)

    Wibmer, Thomas; Rüdiger, Stefan; Heitner, Claudia; Kropf-Sanchen, Cornelia; Blanta, Ioanna; Stoiber, Kathrin M; Rottbauer, Wolfgang; Schumann, Christian

    2014-05-01

    Dynamic hyperinflation is an important target in the treatment of COPD. There is increasing evidence that positive expiratory pressure (PEP) could reduce dynamic hyperinflation during exercise. PEP application through a nasal mask and a flow resistance device might have the potential to be used during daily physical activities as an auxiliary strategy of ventilatory assistance. The aim of this study was to determine the effects of nasal PEP on lung volumes during physical exercise in patients with COPD. Twenty subjects (mean ± SD age 69.4 ± 6.4 years) with stable mild-to-severe COPD were randomized to undergo physical exercise with nasal PEP breathing, followed by physical exercise with habitual breathing, or vice versa. Physical exercise was induced by a standard 6-min walk test (6 MWT) protocol. PEP was applied by means of a silicone nasal mask loaded with a fixed-orifice flow resistor. Body plethysmography was performed immediately pre-exercise and post-exercise. Differences in mean pre- to post-exercise changes in total lung capacity (-0.63 ± 0.80 L, P = .002), functional residual capacity (-0.48 ± 0.86 L, P = .021), residual volume (-0.56 ± 0.75 L, P = .004), S(pO2) (-1.7 ± 3.4%, P = .041), and 6 MWT distance (-30.8 ± 30.0 m, P = .001) were statistically significant between the experimental and the control interventions. The use of flow-dependent expiratory pressure, applied with a nasal mask and a PEP device, might promote significant reduction of dynamic hyperinflation during walking exercise. Further studies are warranted addressing improvements in endurance performance under regular application of nasal PEP during physical activities.

  11. Alternative power supply and dump resistor connections for similar, mutually coupled, superconducting coils

    International Nuclear Information System (INIS)

    Owen, E.W.; Shimer, W.; Wang, S.T.

    1983-01-01

    Alternative methods of connecting similar mutually coupled coils to their power supplies and dump resistors are investigated. The circuits are evaluated for both operating and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the currents induced in coils that remain superconducting when one or more coils quench. The alternative connections include combined power supplies, individual dump resistors, combined resistors and series and parallel dump resistors. A new circuit that contains ''coupling'' resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed. The MFTF-B central-cell solenoids are used as an example

  12. Alternative power supply and dump resistor connections for similar, mutally coupled, superconducting coils

    International Nuclear Information System (INIS)

    Owen, E.W.; Shimer, D.W.; Wang, S.T.

    1983-01-01

    Alternative methods of connecting similar mutually coupled coils to their power supplies and dump resistors are investigated. The circuits are evaluated for both operating and fault conditions. The factors considered are the voltage to ground during a dump, short circuits, open circuits, quenches, and failure of the protection system to detect a quench. Of particular interest are the currents induced in coils that remain superconducting when one or more coils quench. The alternative connections include combined power supplies, individual dump resistors, combined resistors and series and parallel dump resistors. A new circuit that contains coupling resistors is proposed. The coupling resistors do not affect normal fast dumps but reduce the peak induced currents while also reducing the energy rating of the dump resistors. Another novel circuit, the series circuit with diodes, is discussed. The MFTF-B central-cell solenoids are used as an example

  13. System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors

    Science.gov (United States)

    Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

    2013-10-22

    A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

  14. Improved cryo-resistors with low temperature coefficients

    International Nuclear Information System (INIS)

    Warnecke, P.; Braun, E.

    1989-01-01

    A new type of 10- and 12.9κΩ cryo-resistors operating in a liquid helium bath with small temperature coefficient of resistivity have been built. Details for the fabrication of these improved cryo-resistors are reported. Experimental evidence of their drift rates are on the order of a few parts in 10 9 per day. A reduction of the mean pressure of 98.7 kPa in the helium dewar to 86.1 kPa, corresponding to a temperature decrease from 4.19 to 4.07 Κ, did not change the resistance value by more than the experimental resolution of 4 parts in 10 8

  15. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices

    International Nuclear Information System (INIS)

    Lotkhov, Sergey V

    2013-01-01

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage–current characteristics were measured at temperatures down to T ∼ 20 mK for films with sheet resistivities as high as ∼7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current. (paper)

  16. Random resistor network model of minimal conductivity in graphene.

    Science.gov (United States)

    Cheianov, Vadim V; Fal'ko, Vladimir I; Altshuler, Boris L; Aleiner, Igor L

    2007-10-26

    Transport in undoped graphene is related to percolating current patterns in the networks of n- and p-type regions reflecting the strong bipolar charge density fluctuations. Finite transparency of the p-n junctions is vital in establishing the macroscopic conductivity. We propose a random resistor network model to analyze scaling dependencies of the conductance on the doping and disorder, the quantum magnetoresistance and the corresponding dephasing rate.

  17. Effects of positive end-expiratory pressure on renal function.

    Science.gov (United States)

    Järnberg, P O; de Villota, E D; Eklund, J; Granberg, P O

    1978-01-01

    The effects were studied positive end-expiratory pressure (PEEP) on renal function in eight patients with acute respiratory failure, requiring mechanical ventilation. On application of PEEP + 10 cm H2O, central venous pressure increased, systolic blood pressure decreased, urine flow and PAH-clearance were reduced, while inulin clearance remained stable. There was a marked increase in fractional sodium reabsorption and a concurrent decrease in fractional osmolal excretion. Fractional free-water clearance and the ratio UOsm/POsm did change.

  18. Infant breathing rate counter based on variable resistor for pneumonia

    Science.gov (United States)

    Sakti, Novi Angga; Hardiyanto, Ardy Dwi; La Febry Andira R., C.; Camelya, Kesa; Widiyanti, Prihartini

    2016-03-01

    Pneumonia is one of the leading causes of death in new born baby in Indonesia. According to WHO in 2002, breathing rate is very important index to be the symptom of pneumonia. In the Community Health Center, the nurses count with a stopwatch for exactly one minute. Miscalculation in Community Health Center occurs because of long time concentration and focus on two object at once. This calculation errors can cause the baby who should be admitted to the hospital only be attended at home. Therefore, an accurate breathing rate counter at Community Health Center level is necessary. In this work, resistance change of variable resistor is made to be breathing rate counter. Resistance change in voltage divider can produce voltage change. If the variable resistance moves periodically, the voltage will change periodically too. The voltage change counted by software in the microcontroller. For the every mm shift at the variable resistor produce average 0.96 voltage change. The software can count the number of wave generated by shifting resistor.

  19. Defect tolerance in resistor-logic demultiplexers for nanoelectronics.

    Science.gov (United States)

    Kuekes, Philip J; Robinett, Warren; Williams, R Stanley

    2006-05-28

    Since defect rates are expected to be high in nanocircuitry, we analyse the performance of resistor-based demultiplexers in the presence of defects. The defects observed to occur in fabricated nanoscale crossbars are stuck-open, stuck-closed, stuck-short, broken-wire, and adjacent-wire-short defects. We analyse the distribution of voltages on the nanowire output lines of a resistor-logic demultiplexer, based on an arbitrary constant-weight code, when defects occur. These analyses show that resistor-logic demultiplexers can tolerate small numbers of stuck-closed, stuck-open, and broken-wire defects on individual nanowires, at the cost of some degradation in the circuit's worst-case voltage margin. For stuck-short and adjacent-wire-short defects, and for nanowires with too many defects of the other types, the demultiplexer can still achieve error-free performance, but with a smaller set of output lines. This design thus has two layers of defect tolerance: the coding layer improves the yield of usable output lines, and an avoidance layer guarantees that error-free performance is achieved.

  20. Design of a Compact Dump Resistor System for LCD Magnet

    CERN Document Server

    Gaddi, A

    2010-01-01

    In this technical note we suggest a possible solution for the choice of the detector magnet dump resistor. The push-pull scenario for Linear Collider Detectors imposes new solutions for magnet powering and protection lines, else than what developed for LHC detectors. The magnet dump resistor is the protecting equipment that has the function of extracting a significant amount of magnetic stored energy, from the coil winding to a dump. The LCD magnet has to move with the experiment from the garage to the beam position, so it has to be compact and reliable at the same time. We make here a proposal for a passive water-cooled dumper, we calculate the minimum amount of water required, the resistor hot-spot temperature, the overall mechanical design. The electrical part is not covered by this note, as it can be assumed that the solutions adopted by LHC detector magnets, in terms of quench instrumentation, energy extraction and maximum voltage, are not significantly affected by the push-pull scenario.

  1. Diagnostic methods to assess inspiratory and expiratory muscle strength

    Directory of Open Access Journals (Sweden)

    Pedro Caruso

    2015-04-01

    Full Text Available Impairment of (inspiratory and expiratory respiratory muscles is a common clinical finding, not only in patients with neuromuscular disease but also in patients with primary disease of the lung parenchyma or airways. Although such impairment is common, its recognition is usually delayed because its signs and symptoms are nonspecific and late. This delayed recognition, or even the lack thereof, occurs because the diagnostic tests used in the assessment of respiratory muscle strength are not widely known and available. There are various methods of assessing respiratory muscle strength during the inspiratory and expiratory phases. These methods are divided into two categories: volitional tests (which require patient understanding and cooperation; and non-volitional tests. Volitional tests, such as those that measure maximal inspiratory and expiratory pressures, are the most commonly used because they are readily available. Non-volitional tests depend on magnetic stimulation of the phrenic nerve accompanied by the measurement of inspiratory mouth pressure, inspiratory esophageal pressure, or inspiratory transdiaphragmatic pressure. Another method that has come to be widely used is ultrasound imaging of the diaphragm. We believe that pulmonologists involved in the care of patients with respiratory diseases should be familiar with the tests used in order to assess respiratory muscle function.Therefore, the aim of the present article is to describe the advantages, disadvantages, procedures, and clinical applicability of the main tests used in the assessment of respiratory muscle strength.

  2. Impact of expiratory strength training in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Plowman, Emily K; Watts, Stephanie A; Tabor, Lauren; Robison, Raele; Gaziano, Joy; Domer, Amanda S; Richter, Joel; Vu, Tuan; Gooch, Clifton

    2016-06-01

    We evaluated the feasibility and impact of expiratory muscle strength training (EMST) on respiratory and bulbar function in persons with amyotrophic lateral sclerosis (ALS). Twenty-five ALS patients participated in this delayed intervention open-label clinical trial. Following a lead-in period, patients completed a 5-week EMST protocol. Outcome measures included: maximum expiratory pressure (MEP); physiologic measures of swallow and cough; and penetration-aspiration scale (PAS) scores. Of participants who entered the active phase of the study (n = 15), EMST was well tolerated and led to significant increases in MEPs and maximum hyoid displacement during swallowing post-EMST (P < 0.05). No significant differences were observed for PAS scores or cough spirometry measures. EMST was feasible and well tolerated in this small cohort of ALS patients and led to improvements in expiratory force-generating pressures and swallow kinematics. Further investigation is warranted to confirm these preliminary findings. Muscle Nerve 54: 48-53, 2016. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  3. Investigation of OSL signal of resistors from mobile phones for accidental dosimetry

    International Nuclear Information System (INIS)

    Mrozik, A.; Marczewska, B.; Bilski, P.; Gieszczyk, W.

    2014-01-01

    Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al 2 O 3 , which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commercially available resistors, similar in the shape and size to the resistors from circuit board of the studied mobile phone, were situated in different locations inside it. The irradiations were performed in uniform 60 Co and 137 Cs radiation fields, with the mobile phones connected and not connected to the cellular network. The dose decrease of 9% was measured for original resistors situated between circuit board and battery, in comparison to the dose at the front of the phone. The resistors showed the lower signal when the mobile phone was connected to the cellular network, due to higher temperature inside the housing. The profile of fading was investigated within 3 month period for resistors irradiated with 1 Gy of gamma rays to estimate of the fading coefficient. - Highlights: • Impact of a mobile phone mode (switched on/off) on absorbed dose by resistors was showed. • The influence of the temperature during irradiation on absorbed dose was measured. • Dose distribution inside of a mobile phone was performed. • Fading factor of resistors was calculated

  4. Effects of non-fatiguing respiratory muscle loading induced by expiratory flow limitation during strenuous incremental cycle exercise on metabolic stress and circulating natural killer cells.

    Science.gov (United States)

    Rolland-Debord, Camille; Morelot-Panzini, Capucine; Similowski, Thomas; Duranti, Roberto; Laveneziana, Pierantonio

    2017-12-01

    Exercise induces release of cytokines and increase of circulating natural killers (NK) lymphocyte during strong activation of respiratory muscles. We hypothesised that non-fatiguing respiratory muscle loading during exercise causes an increase in NK cells and in metabolic stress indices. Heart rate (HR), ventilation (VE), oesophageal pressure (Pes), oxygen consumption (VO 2 ), dyspnoea and leg effort were measured in eight healthy humans (five men and three women, average age of 31 ± 4 years and body weight of 68 ± 10 kg), performing an incremental exercise testing on a cycle ergometer under control condition and expiratory flow limitation (FL) achieved by putting a Starling resistor. Blood samples were obtained at baseline, at peak of exercise and at iso-workload corresponding to that reached at the peak of FL exercise during control exercise. Diaphragmatic fatigue was evaluated by measuring the tension time index of the diaphragm. Respiratory muscle overloading caused an earlier interruption of exercise. Diaphragmatic fatigue did not occur in the two conditions. At peak of flow-limited exercise compared to iso-workload, HR, peak inspiratory and expiratory Pes, NK cells and norepinephrine were significantly higher. The number of NK cells was significantly related to ΔPes (i.e. difference between the most and the less negative Pes) and plasmatic catecholamines. Loading of respiratory muscles is able to cause an increase of NK cells provided that activation of respiratory muscles is intense enough to induce a significant metabolic stress.

  5. Contact materials for thermostable resistors on the base of Ni-Re alloy

    International Nuclear Information System (INIS)

    Yusipov, H.Yu.; Glasman, L.I.; Arskaya, E.P.; Lazarev, Eh.M.; Korotkov, N.A.

    1979-01-01

    Given are the electron diffraction analysis results and the operational characteristics of the contact materials, used in the heat-resistant thin-filmed resistors (TFR), made on the basis of the Ni-Re system alloy. The results are compared with the pure nickel. Operational tests of the thin-filmed resistors, having (NR10-VP) alloy contacts, showed that the departure of the resistors nominals is almost twice as small as that for the resistors, having pure nickel contacts. The use of this alloy permits to increase the thermal stability and durability of the TFRs, if they are used under extreme conditions

  6. Laser Trimming of CuAlMo Thin-Film Resistors: Effect of Laser Processing Parameters

    Science.gov (United States)

    Birkett, Martin; Penlington, Roger

    2012-08-01

    This paper reports the effect of varying laser trimming process parameters on the electrical performance of a novel CuAlMo thin-film resistor material. The films were prepared on Al2O3 substrates by direct-current (DC) magnetron sputtering, before being laser trimmed to target resistance value. The effect of varying key laser parameters of power, Q-rate, and bite size on the resistor stability and tolerance accuracy were systematically investigated. By reducing laser power and bite size and balancing this with Q-rate setting, significant improvements in resistor stability and resistor tolerance accuracies of less than ±0.5% were achieved.

  7. Electrical Switching of Perovskite Thin-Film Resistors

    Science.gov (United States)

    Liu, Shangqing; Wu, Juan; Ignatiev, Alex

    2010-01-01

    Electronic devices that exploit electrical switching of physical properties of thin films of perovskite materials (especially colossal magnetoresistive materials) have been invented. Unlike some related prior devices, these devices function at room temperature and do not depend on externally applied magnetic fields. Devices of this type can be designed to function as sensors (exhibiting varying electrical resistance in response to varying temperature, magnetic field, electric field, and/or mechanical pressure) and as elements of electronic memories. The underlying principle is that the application of one or more short electrical pulse(s) can induce a reversible, irreversible, or partly reversible change in the electrical, thermal, mechanical, and magnetic properties of a thin perovskite film. The energy in the pulse must be large enough to induce the desired change but not so large as to destroy the film. Depending on the requirements of a specific application, the pulse(s) can have any of a large variety of waveforms (e.g., square, triangular, or sine) and be of positive, negative, or alternating polarity. In some applications, it could be necessary to use multiple pulses to induce successive incremental physical changes. In one class of applications, electrical pulses of suitable shapes, sizes, and polarities are applied to vary the detection sensitivities of sensors. Another class of applications arises in electronic circuits in which certain resistance values are required to be variable: Incorporating the affected resistors into devices of the present type makes it possible to control their resistances electrically over wide ranges, and the lifetimes of electrically variable resistors exceed those of conventional mechanically variable resistors. Another and potentially the most important class of applications is that of resistance-based nonvolatile-memory devices, such as a resistance random access memory (RRAM) described in the immediately following article

  8. An optimized resistor pattern for temperature gradient control in microfluidics

    Science.gov (United States)

    Selva, Bertrand; Marchalot, Julien; Jullien, Marie-Caroline

    2009-06-01

    In this paper, we demonstrate the possibility of generating high-temperature gradients with a linear temperature profile when heating is provided in situ. Thanks to improved optimization algorithms, the shape of resistors, which constitute the heating source, is optimized by applying the genetic algorithm NSGA-II (acronym for the non-dominated sorting genetic algorithm) (Deb et al 2002 IEEE Trans. Evol. Comput. 6 2). Experimental validation of the linear temperature profile within the cavity is carried out using a thermally sensitive fluorophore, called Rhodamine B (Ross et al 2001 Anal. Chem. 73 4117-23, Erickson et al 2003 Lab Chip 3 141-9). The high level of agreement obtained between experimental and numerical results serves to validate the accuracy of this method for generating highly controlled temperature profiles. In the field of actuation, such a device is of potential interest since it allows for controlling bubbles or droplets moving by means of thermocapillary effects (Baroud et al 2007 Phys. Rev. E 75 046302). Digital microfluidics is a critical area in the field of microfluidics (Dreyfus et al 2003 Phys. Rev. Lett. 90 14) as well as in the so-called lab-on-a-chip technology. Through an example, the large application potential of such a technique is demonstrated, which entails handling a single bubble driven along a cavity using simple and tunable embedded resistors.

  9. An optimized resistor pattern for temperature gradient control in microfluidics

    International Nuclear Information System (INIS)

    Selva, Bertrand; Marchalot, Julien; Jullien, Marie-Caroline

    2009-01-01

    In this paper, we demonstrate the possibility of generating high-temperature gradients with a linear temperature profile when heating is provided in situ. Thanks to improved optimization algorithms, the shape of resistors, which constitute the heating source, is optimized by applying the genetic algorithm NSGA-II (acronym for the non-dominated sorting genetic algorithm) (Deb et al 2002 IEEE Trans. Evol. Comput. 6 2). Experimental validation of the linear temperature profile within the cavity is carried out using a thermally sensitive fluorophore, called Rhodamine B (Ross et al 2001 Anal. Chem. 73 4117–23, Erickson et al 2003 Lab Chip 3 141–9). The high level of agreement obtained between experimental and numerical results serves to validate the accuracy of this method for generating highly controlled temperature profiles. In the field of actuation, such a device is of potential interest since it allows for controlling bubbles or droplets moving by means of thermocapillary effects (Baroud et al 2007 Phys. Rev. E 75 046302). Digital microfluidics is a critical area in the field of microfluidics (Dreyfus et al 2003 Phys. Rev. Lett. 90 14) as well as in the so-called lab-on-a-chip technology. Through an example, the large application potential of such a technique is demonstrated, which entails handling a single bubble driven along a cavity using simple and tunable embedded resistors

  10. Conceptual design of dump resistor for superconducting CS of SST-1

    International Nuclear Information System (INIS)

    Roy, Swati; Pradhan, Subrata; Panchal, Arun

    2015-01-01

    During the upgradation of SST-1, the resistive central solenoid (CS) coil has been planned to be replaced with Nb 3 Sn based superconducting coil. The superconducting CS will store upto 3.5MJ of magnetic energy per operation cycle with operating current upto 14kA. In case of coil quench, the energy stored in the coils is to be extracted rapidly with a time constant of 1.5s. This will be achieved by inserting a 20m Ohm dump resistor in series with the superconducting CS which is normally shorted by circuit breakers. As a vital part of the superconducting CS quench protection system, a conceptual design of the 20m Ohm dump resistor has been proposed. In this paper, the required design aspects and a dimensional layout of the dump resistor for the new superconducting CS has been presented. Natural air circulation is proposed as cooling method for this dump resistor. The basic structure of the proposed dump resistor comprises of stainless steel grids connected in series in the shape of meander to minimize the stray inductance and increase the surface area for cooling. The entire dump resistor will be an array of such grids connected in series and parallel to meet electrical as well as thermal parameters. The maximum temperature of the proposed dump resistor is upto 350 °C during dump 3.5MJ energy. The proposed design permits indigenous fabrication of the dump resistor using commercially available welding techniques. (author)

  11. Comparison of boron and neon damage effects in boron ion-implanted resistors

    International Nuclear Information System (INIS)

    MacIver, B.A.

    1975-01-01

    Boron and neon damage implants were used in fabricating integrated-circuit resistors in silicon. Resistor properties were studied as functions of damaging ion species and dose. Sheet resistances in the 10 000 Ω/square range were obtained with low temperature and voltage sensitivities and d.c. isolation. (author)

  12. Characteristics and Breakdown Behaviors of Polysilicon Resistors for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Tang

    2015-01-01

    Full Text Available With the rapid development of the power integrated circuit technology, polysilicon resistors have been widely used not only in traditional CMOS circuits, but also in the high voltage applications. However, there have been few detailed reports about the polysilicon resistors’ characteristics, like voltage and temperature coefficients and breakdown behaviors which are critical parameters of high voltage applications. In this study, we experimentally find that the resistance of the polysilicon resistor with a relatively low doping concentration shows negative voltage and temperature coefficients, while that of the polysilicon resistor with a high doping concentration has positive voltage and temperature coefficients. Moreover, from the experimental results of breakdown voltages of the polysilicon resistors, it could be deduced that the breakdown of polysilicon resistors is thermally rather than electrically induced. We also proposed to add an N-type well underneath the oxide to increase the breakdown voltage in the vertical direction when the substrate is P-type doped.

  13. Implanted Silicon Resistor Layers for Efficient Terahertz Absorption

    Science.gov (United States)

    Chervenak, J. A.; Abrahams, J.; Allen, C. A.; Benford, D. J.; Henry, R.; Stevenson, T.; Wollack, E.; Moseley, S. H.

    2005-01-01

    Broadband absorption structures are an essential component of large format bolometer arrays for imaging GHz and THz radiation. We have measured electrical and optical properties of implanted silicon resistor layers designed to be suitable for these absorbers. Implanted resistors offer a low-film-stress, buried absorber that is robust to longterm aging, temperature, and subsequent metals processing. Such an absorber layer is readily integrated with superconducting integrated circuits and standard micromachining as demonstrated by the SCUBA II array built by ROE/NIST (1). We present a complete characterization of these layers, demonstrating frequency regimes in which different recipes will be suitable for absorbers. Single layer thin film coatings have been demonstrated as effective absorbers at certain wavelengths including semimetal (2,3), thin metal (4), and patterned metal films (5,6). Astronomical instrument examples include the SHARC II instrument is imaging the submillimeter band using passivated Bi semimetal films and the HAWC instrument for SOFIA, which employs ultrathin metal films to span 1-3 THz. Patterned metal films on spiderweb bolometers have also been proposed for broadband detection. In each case, the absorber structure matches the impedance of free space for optimal absorption in the detector configuration (typically 157 Ohms per square for high absorption with a single or 377 Ohms per square in a resonant cavity or quarter wave backshort). Resonant structures with -20% bandwidth coupled to bolometers are also under development; stacks of such structures may take advantage of instruments imaging over a wide band. Each technique may enable effective absorbers in imagers. However, thin films tend to age, degrade or change during further processing, can be difficult to reproduce, and often exhibit an intrinsic granularity that creates complicated frequency dependence at THz frequencies. Thick metal films are more robust but the requirement for

  14. Improved oxygenation during standing performance of deep breathing exercises with positive expiratory pressure after cardiac surgery: A randomized controlled trial.

    Science.gov (United States)

    Pettersson, Henrik; Faager, Gun; Westerdahl, Elisabeth

    2015-09-01

    Breathing exercises after cardiac surgery are often performed in a sitting position. It is unknown whether oxygenation would be better in the standing position. The aim of this study was to evaluate oxygenation and subjective breathing ability during sitting vs standing performance of deep breathing exercises on the second day after cardiac surgery. Patients undergoing coronary artery bypass grafting (n = 189) were randomized to sitting (controls) or standing. Both groups performed 3 × 10 deep breaths with a positive expiratory pressure device. Peripheral oxygen saturation was measured before, directly after, and 15 min after the intervention. Subjective breathing ability, blood pressure, heart rate, and pain were assessed. Oxygenation improved significantly in the standing group compared with controls directly after the breathing exercises (p < 0.001) and after 15 min rest (p = 0.027). The standing group reported better deep breathing ability compared with controls (p = 0.004). A slightly increased heart rate was found in the standing group (p = 0.047). After cardiac surgery, breathing exercises with positive expiratory pressure, performed in a standing position, significantly improved oxygenation and subjective breathing ability compared with sitting performance. Performance of breathing exercises in the standing position is feasible and could be a valuable treatment for patients with postoperative hypoxaemia.

  15. Inclusion of Body Bias Effect in SPICE Modeling of 4H-SiC Integrated Circuit Resistors

    Science.gov (United States)

    Neudeck, Philip G.

    2017-01-01

    The DC electrical behavior of n-type 4H-SiC resistors used for realizing 500 degrees Celsius durable integrated circuits (ICs) is studied as a function of substrate bias and temperature. Improved fidelity electrical simulation is described using SPICE NMOS model to simulate resistor substrate body bias effect that is absent from the SPICE semiconductor resistor model.

  16. Inclusion of Body-Bias Effect in SPICE Modeling of 4H-SiC Integrated Circuit Resistors

    Science.gov (United States)

    Neudeck, Philip G.

    2017-01-01

    The DC electrical behavior of n-type 4H-SiC resistors used for realizing 500 C durable integrated circuits (ICs) is studied as a function of substrate bias and temperature. Improved fidelity electrical simulation is described using SPICE NMOS model to simulate resistor substrate body bias effect that is absent from the SPICE semiconductor resistor model.

  17. Setting individualized positive end-expiratory pressure level with a positive end-expiratory pressure decrement trial after a recruitment maneuver improves oxygenation and lung mechanics during one-lung ventilation.

    Science.gov (United States)

    Ferrando, Carlos; Mugarra, Ana; Gutierrez, Andrea; Carbonell, Jose Antonio; García, Marisa; Soro, Marina; Tusman, Gerardo; Belda, Francisco Javier

    2014-03-01

    We investigated whether individualized positive end-expiratory pressure (PEEP) improves oxygenation, ventilation, and lung mechanics during one-lung ventilation compared with standardized PEEP. Thirty patients undergoing thoracic surgery were randomly allocated to the study or control group. Both groups received an alveolar recruitment maneuver at the beginning and end of one-lung ventilation. After the alveolar recruitment maneuver, the control group had their lungs ventilated with a 5 cm·H2O PEEP, while the study group had their lungs ventilated with an individualized PEEP level determined by a PEEP decrement trial. Arterial blood samples, lung mechanics, and volumetric capnography were recorded at multiple timepoints throughout the procedure. The individualized PEEP values in study group were higher than the standardized PEEP values (10 ± 2 vs 5 cm·H2O; P decrement trial than with a standardized 5 cm·H2O of PEEP.

  18. A novel charge sensitive preamplifier without the feedback resistor

    International Nuclear Information System (INIS)

    Bertuccio, G.

    1992-01-01

    A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward baised gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF

  19. "Weak quantum chaos" and its resistor network modeling.

    Science.gov (United States)

    Stotland, Alexander; Pecora, Louis M; Cohen, Doron

    2011-06-01

    Weakly chaotic or weakly interacting systems have a wide regime where the common random matrix theory modeling does not apply. As an example we consider cold atoms in a nearly integrable optical billiard with a displaceable wall (piston). The motion is completely chaotic but with a small Lyapunov exponent. The Hamiltonian matrix does not look like one taken from a Gaussian ensemble, but rather it is very sparse and textured. This can be characterized by parameters s and g which reflect the percentage of large elements and their connectivity, respectively. For g we use a resistor network calculation that has a direct relation to the semilinear response characteristics of the system, hence leading to a prediction regarding the energy absorption rate of cold atoms in optical billiards with vibrating walls.

  20. Minimum spanning trees and random resistor networks in d dimensions.

    Science.gov (United States)

    Read, N

    2005-09-01

    We consider minimum-cost spanning trees, both in lattice and Euclidean models, in d dimensions. For the cost of the optimum tree in a box of size L , we show that there is a correction of order L(theta) , where theta or =1 . The arguments all rely on the close relation of Kruskal's greedy algorithm for the minimum spanning tree, percolation, and (for some arguments) random resistor networks. The scaling of the entropy and free energy at small nonzero T , and hence of the number of near-optimal solutions, is also discussed. We suggest that the Steiner tree problem is in the same universality class as the minimum spanning tree in all dimensions, as is the traveling salesman problem in two dimensions. Hence all will have the same value of theta=-3/4 in two dimensions.

  1. Carbon resistor pressure gauge calibration at low stresses

    International Nuclear Information System (INIS)

    Cunningham, Bruce; Vandersall, Kevin S.; Niles, Angela M.; Greenwood, Daniel W.; Garcia, Frank; Forbes, Jerry W.; Wilson, William H.

    2002-01-01

    The 470 Ohm carbon resistor gauge has been used in the stress range up to 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. Gauge drawbacks are the long time response to pressure equilibration and gauge resistance hysteresis. In the regime below 0.4 GPa, gauge calibration has been extrapolated. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results are discussed and compared to a calibration curve fit to previously published calibration data

  2. Resistor-less charge sensitive amplifier for semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pelczar, K., E-mail: krzysztof.pelczar@doctoral.uj.edu.pl; Panas, K.; Zuzel, G.

    2016-11-01

    A new concept of a Charge Sensitive Amplifier without a high-value resistor in the feedback loop is presented. Basic spectroscopic parameters of the amplifier coupled to a coaxial High Purity Germanium detector (HPGe) are discussed. The amplifier signal input is realized with an n-channel J-FET transistor. The feedback capacitor is discharged continuously by the second, forward biased n-channel J-FET, driven by an RC low–pass filter. Both the analog—with a standard spectroscopy amplifier and a multi-channel analyzer—and the digital—by applying a Flash Analog to Digital Converter—signal readouts were tested. The achieved resolution in the analog and the digital readouts was 0.17% and 0.21%, respectively, at the Full Width at Half Maximum of the registered {sup 60}Co 1332.5 keV gamma line.

  3. Indium Tin Oxide Resistor-Based Nitric Oxide Microsensors

    Science.gov (United States)

    Xu, Jennifer C.; Hunter, Gary W.; Gonzalez, Jose M., III; Liu, Chung-Chiun

    2012-01-01

    A sensitive resistor-based NO microsensor, with a wide detection range and a low detection limit, has been developed. Semiconductor microfabrication techniques were used to create a sensor that has a simple, robust structure with a sensing area of 1.10 0.99 mm. A Pt interdigitated structure was used for the electrodes to maximize the sensor signal output. N-type semiconductor indium tin oxide (ITO) thin film was sputter-deposited as a sensing material on the electrode surface, and between the electrode fingers. Alumina substrate (250 m in thickness) was sequentially used for sensor fabrication. The resulting sensor was tested by applying a voltage across the two electrodes and measuring the resulting current. The sensor was tested at different concentrations of NO-containing gas at a range of temperatures. Preliminary results showed that the sensor had a relatively high sensitivity to NO at 450 C and 1 V. NO concentrations from ppm to ppb ranges were detected with the low limit of near 159 ppb. Lower NO concentrations are being tested. Two sensing mechanisms were involved in the NO gas detection at ppm level: adsorption and oxidation reactions, whereas at ppb level of NO, only one sensing mechanism of adsorption was involved. The NO microsensor has the advantages of high sensitivity, small size, simple batch fabrication, high sensor yield, low cost, and low power consumption due to its microsize. The resistor-based thin-film sensor is meant for detection of low concentrations of NO gas, mainly in the ppb or lower range, and is being developed concurrently with other sensor technology for multispecies detection. This development demonstrates that ITO is a sensitive sensing material for NO detection. It also provides crucial information for future selection of nanostructured and nanosized NO sensing materials, which are expected to be more sensitive and to consume less power.

  4. The effect of positive end-expiratory pressure on pulse pressure ...

    African Journals Online (AJOL)

    The effect of positive end-expiratory pressure on pulse pressure variation. FJ Smith, M Geyser, I Schreuder, PJ Becker. Abstract. Objectives: To determine the effect of different levels of positive end-expiratory pressure (PEEP) on pulse pressure variation (PPV). Design: An observational study. Setting: Operating theatres of a ...

  5. Parameters affecting the tidal volume during expiratory abdominal compression in patients with prolonged tracheostomy mechanical ventilation.

    Science.gov (United States)

    Morino, Akira; Shida, Masahiro; Tanaka, Masashi; Sato, Kimihiro; Seko, Toshiaki; Ito, Shunsuke; Ogawa, Shunichi; Takahashi, Naoaki

    2015-07-01

    [Purpose] The aim of this study was to clarify physical parameters affecting the tidal volume during expiratory abdominal compression in patients with prolonged tracheostomy mechanical ventilation. [Methods] Eighteen patients with prolonged mechanical ventilation were included in this study. Expiratory abdominal compression was performed on patients lying in a supine position. The abdomen above the navel was vertically compressed in synchronization with expiration and released with inspiration. We measured the tidal volume during expiratory abdominal compression. [Results] The mean tidal volume during expiratory abdominal compression was higher than that at rest (430.6 ± 127.1 mL vs. 344.0 ± 94.3 mL). The tidal volume during expiratory abdominal compression was correlated with weight, days of ventilator support, dynamic compliance and abdominal expansion. Stepwise multiple regression analysis revealed that weight (β = 0.499), dynamic compliance (β = 0.387), and abdominal expansion (β = 0.365) were factors contributing to the tidal volume during expiratory abdominal compression. [Conclusion] Expiratory abdominal compression increased the tidal volume in patients with prolonged tracheostomy mechanical ventilation. The tidal volume during expiratory abdominal compression was influenced by each of the pulmonary conditions and the physical characteristics.

  6. Recursion-transform method for computing resistance of the complex resistor network with three arbitrary boundaries.

    Science.gov (United States)

    Tan, Zhi-Zhong

    2015-05-01

    We develop a general recursion-transform (R-T) method for a two-dimensional resistor network with a zero resistor boundary. As applications of the R-T method, we consider a significant example to illuminate the usefulness for calculating resistance of a rectangular m×n resistor network with a null resistor and three arbitrary boundaries, a problem never solved before, since Green's function techniques and Laplacian matrix approaches are invalid in this case. Looking for the exact calculation of the resistance of a binary resistor network is important but difficult in the case of an arbitrary boundary since the boundary is like a wall or trap which affects the behavior of finite network. In this paper we obtain several general formulas of resistance between any two nodes in a nonregular m×n resistor network in both finite and infinite cases. In particular, 12 special cases are given by reducing one of the general formulas to understand its applications and meanings, and an integral identity is found when we compare the equivalent resistance of two different structures of the same problem in a resistor network.

  7. Electrical properties and conduction mechanisms of Ru-based thick-film (cermet) resistors

    International Nuclear Information System (INIS)

    Pike, G.E.; Seager, C.H.

    1977-01-01

    This paper presents an experimental study of the electrical conduction mechanisms in thick-film (cermet) resistor. The resistors were made from one custom and three commercially formulated inks with sheet resistivities ranging from 10 2 to 10 6 Ω/D 7 Alembertian in decade increments. Their microstructure and composition have been examined using optical and scanning electron microscopy, electron microprobe analysis, x-ray diffraction, and various chemical analyses. This portion of our study shows that the resistors are heterogeneous mixtures of metallic metal oxide particles (approx.4 x 10 -5 cm in diameter) and a lead silicate glass. The metal oxide particles are ruthenium containing pyrochlores, and are joined to form a continuous three-dimensional network of chain segments. The principal experimental work reported here is an extensive study of the electrical transport properties of the resistors. The temperature dependence of conductance has been measured from 1.2 to 400 K, and two features common to all resistors are found. There is a pronounced decrease in conductance at low temperatures and a shallow maximum at several hundred Kelvin. Within the same range of temperatures the reversible conductance as a function of electric field from 0 to 28 kV/cm has been studied. The resistors are non-Ohmic at all temperatures, but particularly at cryogenic temperatures for low fields. At higher fields the conductance shows a linear variation with electric field. The thick-film resistors are found to have a small dielectric constant and a (nearly) frequency-independent conductance from dc to 50 MHz. The magnetoresistance to 100 kG, the Hall mobility, and the Seebeck coefficient of most of the resistors have been measured and discovered to be quite small. Many of the electrical transport properties have also been determined for the metal oxide particles which were extracted from the fired resistors

  8. Characteristics of burden resistors for high-precision DC current transducers

    CERN Document Server

    Fernqvist, G; Hudson, G; Pickering, J

    2007-01-01

    The DC current transducer (DCCT) and accompanying A/D converter determine the precision of a power converter in accelerator operation. In the LHC context this precision approaches 10-6 (1 ppm). Inside the DCCT a burden resistor is used to convert the current to an output voltage. The performance of this resistor is crucial for the accuracy, temperature behaviour, settling time and longterm drift of the DCCT. This paper reports on evaluations, a new parameter called â€ワpower coefficient” (PC) and test results from some different types of resistors available on the market.

  9. A random access memory immune to single event upset using a T-Resistor

    Science.gov (United States)

    Ochoa, A. Jr.

    1987-10-28

    In a random access memory cell, a resistance ''T'' decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell. 4 figs.

  10. Random access memory immune to single event upset using a T-resistor

    Science.gov (United States)

    Ochoa, Jr., Agustin

    1989-01-01

    In a random access memory cell, a resistance "T" decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell.

  11. Thermal resistor on the base of silicon and some polymer semiconductors

    International Nuclear Information System (INIS)

    Marupov, R.; Kasimov, Sh.T.; Achilov, T.Kh.; Karimov, Kh.S.; Akhmedov, Kh.M.

    1995-01-01

    The purpose of present work is investigation electrical properties ofthermal resistors which was made from second cast poly-crystal silicon,poly-carbazole, and compositions of poly-crystal silicon and poly-carbazole

  12. A low-cost DAC BIST structure using a resistor loop.

    Directory of Open Access Journals (Sweden)

    Jaewon Jang

    Full Text Available This paper proposes a new DAC BIST (digital-to-analog converter built-in self-test structure using a resistor loop known as a DDEM ADC (deterministic dynamic element matching analog-to-digital converter. Methods for both switch reduction and switch effect reduction are proposed for solving problems related to area overhead and accuracy of the conventional DAC BIST. The proposed BIST modifies the length of each resistor in the resistor loop via a merging operation and reduces the number of switches and resistors. In addition, the effect of switches is mitigated using the proposed switch effect reduction method. The accuracy of the proposed BIST is demonstrated by the reduction in the switch effect. The experimental results show that the proposed BIST reduces resource usages and the mismatch error caused by the switches.

  13. Advanced ceramic composite for high energy resistors. Characterization of electrical and physical properties

    International Nuclear Information System (INIS)

    Farrokh, Fattahi; Navid, Tagizadegan; Naser, Tabatabaei; Ahmad, Rashtehizadeh

    2005-01-01

    There is a need to characterize and apply advanced materials to improve the performance of components used in pulse power systems. One area of innovation is the use of bulk electrically conductive ceramics for non-inductive, high energy and high power electrical resistors. Standard Ceramics Inc. has developed a unique silicon carbide structural ceramic composite which exhibits electrical conductivity. The new conductive bulk ceramic material has a controlled microstructure, which results in improved homogeneity, making the material suitable for use as a non-inductive high energy resistor. This paper describes characterization of the material's physical and electrical properties and relates them to improvements in low-inductance, high temperature, high power density and high energy density resistors. The bulk resistor approach offers high reliability through better mechanical properties and simplicity of construction

  14. A low-cost DAC BIST structure using a resistor loop.

    Science.gov (United States)

    Jang, Jaewon; Kim, Heetae; Kang, Sungho

    2017-01-01

    This paper proposes a new DAC BIST (digital-to-analog converter built-in self-test) structure using a resistor loop known as a DDEM ADC (deterministic dynamic element matching analog-to-digital converter). Methods for both switch reduction and switch effect reduction are proposed for solving problems related to area overhead and accuracy of the conventional DAC BIST. The proposed BIST modifies the length of each resistor in the resistor loop via a merging operation and reduces the number of switches and resistors. In addition, the effect of switches is mitigated using the proposed switch effect reduction method. The accuracy of the proposed BIST is demonstrated by the reduction in the switch effect. The experimental results show that the proposed BIST reduces resource usages and the mismatch error caused by the switches.

  15. High-ohmic low-noise resistor for spectrometers with cooled semiconductor detectors

    International Nuclear Information System (INIS)

    Baldin, S.A.; Zhargal, Ch.; Zorin, G.N.; Laskus, T.; Osipenko, B.P.; Revenko, A.V.; Ryakhovskaya, T.I.

    1985-01-01

    BackgroUnd noise and energy resolution of a new type of resistors, designed to be used as a resistance in a feedback circuit of an X-ray spectrometer preamplifier are studied. The resistors are manufactured using the method of photolithography from high-resistance films, formed on the surface of lead-silicate glasses, as a result of redox processes during heat treatment in hydrogen atmosphere. Energy resolution of the spectrometer is measured on the line 55 FeKX(Mn) with the energy 5.8 keV. The conclusion is made, that the level of background noises in the resistors studied is approximately 4 times lower the level of noises in the KVM type resistors, which are commercially produced in industry

  16. Improving the transient response of a bolt-clamped Langevin transducer using a parallel resistor.

    Science.gov (United States)

    Chang, Kuo Tsi

    2003-08-01

    This paper suggests a parallel resistor to reduce DC time constant and DC response time of the transient response, induced immediately after an AC voltage connected to a bolt-clamped Langevin transducer (BLT) is switched off. An equivalent circuit is first expressed. Then, an open-circuit transient response at the terminals induced by initial states is derived and measured, and thus parameters for losses of the BLT device are estimated by DC and AC time constants of the transient response. Moreover, a driving and measuring system is designed to determine transient response and steady-state responses of the BLT device, and a parallel resistor is connected to the BLT device to reduce the DC time constant. Experimental results indicate that the DC time constant greatly exceeds the AC time constant without the parallel resistor, and greatly decreases from 42 to 1 ms by a 100-kOmega parallel resistor.

  17. Ceramic composite resistors of B4C modified by TIO2 and glass phase

    International Nuclear Information System (INIS)

    Klimiec, E.; Zaraska, W.; Stobiecki, T.

    1998-01-01

    Technical progress in the manufacturing technology of composite materials resulted in arising of new generation of bulk resistors, resistant to high levels of overloads and high temperature. These resistors can be applied in extremely heavy working conditions, for instance in cooperation with ignition circuits. The resistors investigated in our research were performed on the basis of ceramic composite consisted of semiconductor boron carbide B 4 C as conductive phase, aluminium oxide Al 2 O 3 and non-alkali glass as insulators and titanium dioxide TiO 2 . The technological procedure of the fabrication of resistors and the results of the tests, such as temperature dependence of the electrical resistance exploitation trials, are presented. (author)

  18. A new method of removing the high value feedback resistor in the charge sensitive preamplifier

    International Nuclear Information System (INIS)

    Xi Deming

    1993-01-01

    A new method of removing the high value feedback resistor in the charge sensitive preamplifier is introduced. The circuit analysis of this novel design is described and the measured performances of a practical circuit are provided

  19. Design and fabrication of carbon nanotube field-emission cathode with coaxial gate and ballast resistor.

    Science.gov (United States)

    Sun, Yonghai; Yeow, John T W; Jaffray, David A

    2013-10-25

    A low density vertically aligned carbon nanotube-based field-emission cathode with a ballast resistor and coaxial gate is designed and fabricated. The ballast resistor can overcome the non-uniformity of the local field-enhancement factor at the emitter apex. The self-aligned fabrication process of the coaxial gate can avoid the effects of emitter tip misalignment and height non-uniformity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Automated crack detection in conductive smart-concrete structures using a resistor mesh model

    Science.gov (United States)

    Downey, Austin; D'Alessandro, Antonella; Ubertini, Filippo; Laflamme, Simon

    2018-03-01

    Various nondestructive evaluation techniques are currently used to automatically detect and monitor cracks in concrete infrastructure. However, these methods often lack the scalability and cost-effectiveness over large geometries. A solution is the use of self-sensing carbon-doped cementitious materials. These self-sensing materials are capable of providing a measurable change in electrical output that can be related to their damage state. Previous work by the authors showed that a resistor mesh model could be used to track damage in structural components fabricated from electrically conductive concrete, where damage was located through the identification of high resistance value resistors in a resistor mesh model. In this work, an automated damage detection strategy that works through placing high value resistors into the previously developed resistor mesh model using a sequential Monte Carlo method is introduced. Here, high value resistors are used to mimic the internal condition of damaged cementitious specimens. The proposed automated damage detection method is experimentally validated using a 500 × 500 × 50 mm3 reinforced cement paste plate doped with multi-walled carbon nanotubes exposed to 100 identical impact tests. Results demonstrate that the proposed Monte Carlo method is capable of detecting and localizing the most prominent damage in a structure, demonstrating that automated damage detection in smart-concrete structures is a promising strategy for real-time structural health monitoring of civil infrastructure.

  1. Sensitivity enhancement of polysilicon piezo-resistive pressure sensors with phosphorous diffused resistors

    International Nuclear Information System (INIS)

    Sivakumar, K; Dasgupta, N; Bhat, K N; Natarajan, K

    2006-01-01

    It is generally accepted that the piezo-resistive coefficient in single crystal silicon is higher when P-type impurities such as boron are used for doping the resistors. In this paper we demonstrate that the sensitivity of polycrystalline silicon piezo-resistive pressure sensors can be enhanced considerably when phosphorus diffusion source is used instead of boron dopant for realizing the piezo-resistors. Pressure sensors have been designed and fabricated with the polycrystalline piezo-resistors connected in the form of a Wheatstone bridge and laid out on thermal oxide grown on membranes obtained with a Silicon On Insulator (SOI) approach. The SOI wafers required for this purpose have been realized in-house by Silicon Fusion Bonding (SFB) and etch back technique in our laboratory. This approach provides excellent isolation between the resistors and enables zero temperature coefficient of the polysilicon resistor. The results obtained in our laboratory have clearly demonstrated that by optimizing the phosphorus diffusion temperature and duration, it is possible to achieve sensitivities in excess of 20mV /Bar for bridge input voltage of 10V, with linearity within 1% over a differential pressure range up to 10Bar (10 6 Pascal), and burst pressure in excess of 50 Bar as compared to the 10mV /Bar sensitivity obtained with boron doped polysilicon piezo-resistors. This enhancement is attributed to grain boundary passivation by phosphorous atoms

  2. An HIV feedback resistor: auto-regulatory circuit deactivator and noise buffer.

    Science.gov (United States)

    Weinberger, Leor S; Shenk, Thomas

    2007-01-01

    Animal viruses (e.g., lentiviruses and herpesviruses) use transcriptional positive feedback (i.e., transactivation) to regulate their gene expression. But positive-feedback circuits are inherently unstable when turned off, which presents a particular dilemma for latent viruses that lack transcriptional repressor motifs. Here we show that a dissipative feedback resistor, composed of enzymatic interconversion of the transactivator, converts transactivation circuits into excitable systems that generate transient pulses of expression, which decay to zero. We use HIV-1 as a model system and analyze single-cell expression kinetics to explore whether the HIV-1 transactivator of transcription (Tat) uses a resistor to shut off transactivation. The Tat feedback circuit was found to lack bi-stability and Tat self-cooperativity but exhibited a pulse of activity upon transactivation, all in agreement with the feedback resistor model. Guided by a mathematical model, biochemical and genetic perturbation of the suspected Tat feedback resistor altered the circuit's stability and reduced susceptibility to molecular noise, in agreement with model predictions. We propose that the feedback resistor is a necessary, but possibly not sufficient, condition for turning off noisy transactivation circuits lacking a repressor motif (e.g., HIV-1 Tat). Feedback resistors may be a paradigm for examining other auto-regulatory circuits and may inform upon how viral latency is established, maintained, and broken.

  3. Transport of expiratory droplets in an aircraft cabin.

    Science.gov (United States)

    Gupta, Jitendra K; Lin, Chao-Hsin; Chen, Qingyan

    2011-02-01

    The droplets exhaled by an index patient with infectious disease such as influenza or tuberculosis may be the carriers of contagious agents. Indoor environments such as the airliner cabins may be susceptible to infection from such airborne contagious agents. The present investigation computed the transport of the droplets exhaled by the index patient seated in the middle of a seven-row, twin-aisle, fully occupied cabin using the CFD simulations. The droplets exhaled were from a single cough, a single breath, and a 15-s talk of the index patient. The expiratory droplets were tracked by using Lagrangian method, and their evaporation was modeled. It was found that the bulk airflow pattern in the cabin played the most important role on the droplet transport. The droplets were contained in the row before, at, and after the index patient within 30 s and dispersed uniformly to all the seven rows in 4 minutes. The total airborne droplet fraction reduced to 48, 32, 20, and 12% after they entered the cabin for 1, 2, 3, and 4 min, respectively, because of the ventilation from the environmental control system. It is critical to predict the risk of airborne infection to take appropriate measures to control and mitigate the risk. Most of the studies in past either assume a homogenous distribution of contaminants or use steady-state conditions. The present study instead provides information on the transient movement of the droplets exhaled by an index passenger in an aircraft cabin. These droplets may contain active contagious agents and can be potent enough to cause infection. The findings can be used by medical professionals to estimate the spatial and temporal distribution of risk of infection to various passengers in the cabin. © 2010 John Wiley & Sons A/S.

  4. Physiological and morphological determinants of maximal expiratory flow in chronic obstructive lung disease

    NARCIS (Netherlands)

    H.A.W.M. Tiddens (Harm); J.M. Bogaard (Jan); J.C. de Jongste (Johan); W.C.J. Hop (Wim); H.O. Coxson (Harvey); P.D. Pare

    1996-01-01

    textabstractMaximal expiratory flow in chronic obstructive pulmonary disease (COPD) could be reduced by three different mechanisms; loss of lung elastic recoil, decreased airway conductance upstream of flow-limiting segments; and increased collapsibility of airways.

  5. Evaluation of Peak Expiratory Flow Rates (PEFR) of Workers in a ...

    African Journals Online (AJOL)

    DATONYE ALASIA

    and knowledge of occupational health associated with the ... the respiratory system with significant. 5 ... Peak Expiratory Flow Rates (PEFR) of workers in a cement factory — Douglas K. E, Alasia D. D. ... history of cigarette smoking and chronic.

  6. Peak expiratory flow variability, bronchial responsiveness, and susceptibility to ambient air pollution in adults

    NARCIS (Netherlands)

    Boezen, M; Schouten, Jan; Rijcken, B; Vonk, J; Gerritsen, J; Hoek, G; Brunekreef, B; Postma, D

    1998-01-01

    Bronchial hyperresponsiveness (BHR) and peak expiratory flow (PEF) variability are associated expressions of airway lability, yet probably reflect different underlying pathophysiologic mechanisms. We investigated whether both measures can be used interchangeably to identify subjects who are

  7. Noise properties of Pb/Cd-free thick film resistors

    International Nuclear Information System (INIS)

    Stadler, Adam Witold; Kolek, Andrzej; Zawislak, Zbigniew; Mleczko, Krzysztof; Jakubowska, Malgorzata; Kielbasinski, Konrad Rafal; Mlozniak, Anna

    2010-01-01

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO 2 - and CaRuO 3 -based thick films screen printed on alumina substrates. Experiments were performed in the temperature range 77-300 K and the frequency range 0.5-5000 Hz with multiterminal devices. The measured noise has been recognized as resistance noise that consists of background 1/f noise and components generated by several thermally activated noise sources (TANSs) of different activation energies. The total noise has been composed of the contributions generated in the resistive layer and in the resistive/conductive layers interface. These noise sources are non-uniformly distributed in the resistor volume. Noise intensity of new-resistive layers has been described by the noise parameter C bulk . Pb/Cd-free layers turned out to be noisier than their Pb-containing counterparts; however, the removal of Pb and Cd from resistive composition is hardly responsible for the increase in the noise. In the case of RuO 2 layers noise increases most likely due to larger grain size of RuO 2 powder used to prepare resistive pastes. Information on the quality of the resistive-to-conductive layers interface occurred to be stored in the values of noise parameter C int . Pb/Cd-free RuO 2 -based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO 3 -based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

  8. Use of tidal breathing curves for evaluating expiratory airway obstruction in infants.

    Science.gov (United States)

    Hevroni, Avigdor; Goldman, Aliza; Blank-Brachfeld, Miriam; Abu Ahmad, Wiessam; Ben-Dov, Lior; Springer, Chaim

    2018-01-15

    To evaluate tidal breathing (TB) flow-volume and flow-time curves for identification of expiratory airway obstruction in infants. Pulmonary function tests were analyzed retrospectively in 156 infants aged 3-24 months with persistent or recurrent respiratory complaints. Parameters derived from TB curves were compared to maximal expiratory flow at functional residual capacity ([Formula: see text]maxFRC) measured by rapid thoracoabdominal compression technique. Analyzed parameters were: inspiratory time (t I ), expiratory time (t E ), tidal volume, peak tidal expiratory flow (PTEF), time to peak tidal expiratory flow (t PTEF ), expiratory flow when 50% and 25% of tidal volume remains in the lungs (FEF 50 , FEF 25 , respectively), and the ratios t PTEF /t E , t I /t E , FEF 50 /PTEF, and FEF 25 /PTEF. Statistical comparisons between flow indices and TB parameters were performed using mean squared error and Pearson's sample correlation coefficient. The study population was also divided into two groups based on severity of expiratory obstruction (above or below z-score for [Formula: see text]maxFRC of -2) to generate receiver operating characteristic (ROC) curves and calculate discriminatory values between the groups. TB parameters that were best correlated to [Formula: see text]maxFRC were: t PTEF /t E , FEF 50 /PTEF, and FEF 25 /PTEF, with r = 0.61, 0.67, 0.65, respectively (p < 0.0001 for all). ROC curves for FEF 50 /PTEF, FEF 25 /PTEF and t PTEF /t E showed areas under the curve of 0.813, 0.797, and 0.796, respectively. Cutoff value z-scores of -0.35, -0.34, and -0.43 for these three parameters, respectively, showed an 86% negative predictive value for severe airway obstructions. TB curves can assist in ruling out severe expiratory airway obstruction in infants.

  9. Study and field verification of the effects of removing closing resistors from 500 kV circuit breakers

    International Nuclear Information System (INIS)

    Selin, D.A.; Agrawal, B.L.; Farmer, R.G.; Demcko, J.A.

    1992-01-01

    Closing resistors in EHV circuit breakers are frequently used to reduce switching transients on lines thus preventing flashovers during line energization. Maintenance and failures of such closing resistors can be costly and reduce transmission system reliability. For these reasons, APS conducted an investigation into the technical feasibility of operating its 500 kV without closing resistors. This paper describes study results of removing closing resistors from 500 kV breakers in a system which employs older technology silicon carbide type surge arresters. The paper also describes results of field tests of the expected flashover rates calculated in the study. These field tests involve repeatedly energizing a 258 mile 500 kV line using a breaker in which the closing resistors are disabled. Transient overvoltages captured during the tests are compared with predicted overvoltages. The study concludes that closing resistors may be removed from the subject system without unacceptable consequences

  10. New internal multi-range resistors for ac voltage calibration by using TVC

    International Nuclear Information System (INIS)

    Ali, Rasha S M

    2015-01-01

    Accurate calibration of ac voltages up to 1000 V by using thermal converters requires range resistors connected in series with the converter. The combination of a thermal converter and range resistor is known as the thermal voltage converter. In this paper, multi-range internal range resistors are designed and implemented in the National Institute for Standards (NIS), Egypt to cover the ac voltage ranges from 10 V to 750 V. The range resistor values are 2 kΩ, 10 kΩ, 20 kΩ, 40 kΩ, 100 kΩ, and 150 kΩ to cover the voltage ranges 10 V, 50 V, 100 V, 200 V, 500 V, and 750 V, respectively. The six range resistors are mounted in series with a single-junction thermo-element in the same box to provide a new thermal voltage converter. The required range resistor is selected by using a six-pin selector switch. Each resistor is connected to a selector pin. The new thermal voltage converter ranges are automatically calibrated against other standard thermal voltage converters at different frequencies by using a LabVIEW program to determine their ac–dc transfer difference at each range. The expanded uncertainties are estimated according to the GUM for all ranges at different frequencies. The performance of the new thermal voltage converter is also evaluated by comparing its ac–dc differences and its accuracy in measuring the ac voltage at different frequencies with a traditional thermal voltage converter. (paper)

  11. Decreased peak expiratory flow in pediatric passive smokers

    Directory of Open Access Journals (Sweden)

    Fitri Yanti

    2011-08-01

    Full Text Available Background Indonesia ranks fifth among countries with the highest aggregate levels of tobacco consumption in the world. Infants and children exposed to environmental tobacco smoke have increased rates of asthma, respiratory and ear infections, as well as reduced lung function. The effects of tobacco smoke exposure on lung function in children have been reported to be dependent on the source of smoke and the length and dose of exposure. Lung function may also be affected by a child’s gender and asthma status. Objective To compare peak expiratory flow (PEF in pediatric passive smokers to that of children not exposed to second hand smoke, and to define factors that may affect PEF in passive smokers. Methods In August 2009 we conducted a cross-sectional study at an elementary school in the Langkat district. Subjects were aged 6 to 12 years, and divided into two groups: passive smokers and those not exposed to secondhand smoke. Subjects’ PEFs were measured with a Mini-Wright peak flow meter. Measurements were performed in triplicate with the highest value recorded as the PEF. Demographic data including age, sex, weight, height, family income, parental education levels and occupations were obtained through questionnaires. Results Of the 170 participants, 100 were passive smokers and 70 were not exposed to secondhand smoke. Age distribution, weight and height were similar in both groups. We observed a significant difference in PEFs between the group of passive smokers and the group not exposed to secondhand smoke, 211.3 L/minute (SD 61.08 and 242.7 L/minute (SD 77.09, respectively (P < 0.005. The number of years of exposure to smoke (P = 0.079 and the number of cigarettes smoked daily in the household (P = 0.098 did not significantly influence PEF. Conclusion The PEF in pediatric passive smokers was significantly lower than that of children not exposed to secondhand smoke. PEF in passive smokers was not influenced by the number of years of smoke

  12. Architecture design of resistor/FET-logic demultiplexer for hybrid CMOS/nanodevice circuit interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Li Shu; Zhang Tong [Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)], E-mail: lis4@rpi.edu, E-mail: tzhang@ecse.rpi.edu

    2008-05-07

    Hybrid nanoelectronics consisting of nanodevice crossbars on top of CMOS backplane circuits is emerging as one viable option to sustain Moore's law after the CMOS scaling limit is reached. One main design challenge in such hybrid nanoelectronics is the interface between the highly dense nanowires in nanodevice crossbars and relatively coarse microwires in the CMOS domain. Such an interface can be realized through a logic circuit called a demultiplexer (demux). In this context, all the prior work on demux design uses a single type of device, such as resistor, diode or field effect transistor (FET), to realize the demultiplexing function. However, different types of devices have their own advantages and disadvantages in terms of functionality, manufacturability, speed and power consumption. This makes none of them provide a satisfactory solution. To tackle this challenge, this work proposes to combine resistor with FET to implement the demux, leading to the hybrid resistor/FET-logic demux. Such hybrid demux architecture can make these two types of devices complement each other well to improve the overall demux design effectiveness. Furthermore, due to the inevitable fabrication process variations at the nanoscale, the effects of resistor conductance and FET threshold voltage variability are analyzed and evaluated based on computer simulations. The simulation results provide the requirement on the fabrication process to ensure a high demux reliability, and promise the hybrid resistor/FET-logic demux an improved addressability and process variance tolerance.

  13. Architecture design of resistor/FET-logic demultiplexer for hybrid CMOS/nanodevice circuit interconnect.

    Science.gov (United States)

    Li, Shu; Zhang, Tong

    2008-05-07

    Hybrid nanoelectronics consisting of nanodevice crossbars on top of CMOS backplane circuits is emerging as one viable option to sustain Moore's law after the CMOS scaling limit is reached. One main design challenge in such hybrid nanoelectronics is the interface between the highly dense nanowires in nanodevice crossbars and relatively coarse microwires in the CMOS domain. Such an interface can be realized through a logic circuit called a demultiplexer (demux). In this context, all the prior work on demux design uses a single type of device, such as resistor, diode or field effect transistor (FET), to realize the demultiplexing function. However, different types of devices have their own advantages and disadvantages in terms of functionality, manufacturability, speed and power consumption. This makes none of them provide a satisfactory solution. To tackle this challenge, this work proposes to combine resistor with FET to implement the demux, leading to the hybrid resistor/FET-logic demux. Such hybrid demux architecture can make these two types of devices complement each other well to improve the overall demux design effectiveness. Furthermore, due to the inevitable fabrication process variations at the nanoscale, the effects of resistor conductance and FET threshold voltage variability are analyzed and evaluated based on computer simulations. The simulation results provide the requirement on the fabrication process to ensure a high demux reliability, and promise the hybrid resistor/FET-logic demux an improved addressability and process variance tolerance.

  14. Architecture design of resistor/FET-logic demultiplexer for hybrid CMOS/nanodevice circuit interconnect

    International Nuclear Information System (INIS)

    Li Shu; Zhang Tong

    2008-01-01

    Hybrid nanoelectronics consisting of nanodevice crossbars on top of CMOS backplane circuits is emerging as one viable option to sustain Moore's law after the CMOS scaling limit is reached. One main design challenge in such hybrid nanoelectronics is the interface between the highly dense nanowires in nanodevice crossbars and relatively coarse microwires in the CMOS domain. Such an interface can be realized through a logic circuit called a demultiplexer (demux). In this context, all the prior work on demux design uses a single type of device, such as resistor, diode or field effect transistor (FET), to realize the demultiplexing function. However, different types of devices have their own advantages and disadvantages in terms of functionality, manufacturability, speed and power consumption. This makes none of them provide a satisfactory solution. To tackle this challenge, this work proposes to combine resistor with FET to implement the demux, leading to the hybrid resistor/FET-logic demux. Such hybrid demux architecture can make these two types of devices complement each other well to improve the overall demux design effectiveness. Furthermore, due to the inevitable fabrication process variations at the nanoscale, the effects of resistor conductance and FET threshold voltage variability are analyzed and evaluated based on computer simulations. The simulation results provide the requirement on the fabrication process to ensure a high demux reliability, and promise the hybrid resistor/FET-logic demux an improved addressability and process variance tolerance

  15. Effects of high voltage pulse trimming on structural properties of thick-film resistors

    Directory of Open Access Journals (Sweden)

    Stanimirović Zdravko

    2017-01-01

    Full Text Available Nowadays, compact and reliable electronic devices including up-to-date ceramic micro-electro-mechanical systems require thick-film resistors with significantly reduced dimensions and stable and precise resistance values. For that reason, instead of standard laser trimming method, high voltage pulse trimming of thick-film resistors is being introduced. This method allows controlled and reliable resistance adjustment regardless of resistor position or dimensions and without the presence of cuts. However, it causes irreversible structural changes in the pseudorandom network formed during sintering causing the changes in conducting mechanisms. In this paper results of the experimental investigation of high voltage pulse trimming of thick-film resistors are presented. Obtained results are analyzed and correlations between resistance and low-frequency noise changes and changes in conducting mechanisms in resistors due to high voltage pulse trimming are observed. Sources of measured fluctuations are identified and it is shown that this type of trimming is a valid alternative trimming method to the dominant laser trimming. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III44003 and III45007

  16. Conceptual design of Dump resistor for Superconducting CS of SST-1

    Science.gov (United States)

    Roy, Swati; Raj, Piyush; Panchal, Arun; Pradhan, Subrata

    2017-04-01

    Under upgradation activities for SST-1, the existing resistive central solenoid (CS) coil will be replaced with Nb3Sn based superconducting coil. Design of Central solenoid had been completed and some of the initiative has already taken for its manufacturing. The superconducting CS will store upto 3 MJ of magnetic energy per operation cycle with operating current upto 14 kA. During quench, energy stored in the coils has to be extracted rapidly with a time constant of 1.5 s by inserting a 20 mΩ dump resistor in series with the superconducting CS which is normally shorted by circuit breakers. As a critical part of the superconducting CS quench protection system, a conceptual design of the 20 mΩ dump resistor has been proposed. The required design aspects and a dimensional layout of the dump resistor for the new superconducting CS has been presented and discussed. The basic structure of the proposed dump resistor comprises of stainless steel grids connected in series in the form of meander to minimize the stray inductance and increase the surface area for cooling. Such an array of grids connected in series and parallel will cater to the electrical as well as thermal parameters. It will be cooled by natural convection. During operation, the estimated maximum temperature of the proposed dump resistor will raise upto 600 K.

  17. A novel pseudo resistor structure for biomedical front-end amplifiers.

    Science.gov (United States)

    Yu-Chieh Huang; Tzu-Sen Yang; Shun-Hsi Hsu; Xin-Zhuang Chen; Jin-Chern Chiou

    2015-08-01

    This study proposes a novel pseudo resistor structure with a tunable DC bias voltage for biomedical front-end amplifiers (FEAs). In the proposed FEA, the high-pass filter composed of differential difference amplifier and a pseudo resistor is implemented. The FEA is manufactured by using a standard TSMC 0.35 μm CMOS process. In this study, three types FEAs included three different pseudo resistor are simulated, fabricated and measured for comparison and electrocorticography (ECoG) measurement, and all the results show the proposed pseudo resistor is superior to other two types in bandwidth. In chip implementation, the lower and upper cutoff frequencies of the high-pass filter with the proposed pseudo resistor are 0.15 Hz and 4.98 KHz, respectively. It also demonstrates lower total harmonic distortion performance of -58 dB at 1 kHz and higher stability with wide supply range (1.8 V and 3.3 V) and control voltage range (0.9 V and 1.65 V) than others. Moreover, the FEA with the proposed pseudo successfully recorded spike-and-wave discharges of ECoG signal in in vivo experiment on rat with pentylenetetrazol-induced seizures.

  18. SEU simulation and testing of resistor-hardened D-latches in the SA3300 microprocessor

    International Nuclear Information System (INIS)

    Sexton, F.W.; Corbett, W.T.; Treece, R.K.; Hass, K.J.; Axness, C.L.; Hash, G.L.; Shaneyfelt, M.R.; Wunsch, T.F.; Hughes, K.L.

    1991-01-01

    In this paper the SEU tolerance of the SA3300 microprocessor with feedback resistors is presented and compared to the SA3300 without feedback resistors and to the commercial version (NS32016). Upset threshold at room temperature increased from 23 MeV-cm 2 /mg and 180 MeV-cm 2 /mg with feedback resistors of 50 kΩ and 160 kΩ, respectively. The performance goal of 10 MHz over the full temperature range of -55 degrees C to +125 degrees C is exceeded for feedback resistors of 160 kΩ and less. Error rate calculations for this design predict that the error rate is less than once every 100 years when 50 kΩ feedback resistors are used in the D-latch design. Analysis of the SEU response using a lumped-parameter circuit simulator imply a charge collection depth of 4.5 μm. This is much deeper than the authors would expect for prompt collection in the epi and funnel regions and has been explained in terms of diffusion current in the heavily doped substrate

  19. Chemical interaction in resistors based on lead ruthenite with additions of niobium(5) oxide compounds

    International Nuclear Information System (INIS)

    Lozinskij, N.S.; Shevtsova, N.A.; Gruba, A.I.; Volkov, V.I.

    1986-01-01

    The method of X-ray phase analysis was used to study chemical interaction in isothermal cross-section of Pb 2 RU 2 O 6 -Nb 2 O 5 , Rbsub(2)Rusub(2)Osub(6)-NbWOsub(5.5) and Rb 2 Ru 2 O 6 -Pb 2 Nb 2 O 7 systems at 850 deg C as well as in models of real ruthenium resistors. Chemical interaction is stated to take place in systems with niobium (5) oxide and NbWOsub(5.5). Niobium (5) and tungsten (6) displace ruthenium (4) from its compounds with formation of their lead salts. Similar chemical interactions between current-carrying phase of the resistor and modifiers representing niobium-containing take place in models of components of the studied systems take place in models of resistors

  20. A fully integrated, monolithic, cryogenic charge sensitive preamplifier using N-channel JFETs and polysilicon resistors

    International Nuclear Information System (INIS)

    Jung, T.S.; Guckel, H.; Seefeldt, J.; Ott, G.; Ahn, Y.C.

    1994-01-01

    In this paper, an integrated charge preamplifier to be used with small (10--30 mm 2 ) Si(Li) and Ge(Li) X-ray detectors is described. The preamplifier is designed to operate at cryogenic temperatures (∼100 K to 160 K) for the best performance. An N-channel JFET process technology for integrated charge sensitive preamplifiers has been developed. The process integrates multiple pinch-off voltage JFETs fabricated in an n-type epitaxial layer on a low resistivity p-type substrate. The process also incorporates polysilicon resistors integrated on the same die as the JFETs. The optimized polysilicon resistors exhibit 1/f noise nearly as good as metal film resistors at the same current. Results for integrated amplifier are discussed

  1. Split-cross-bridge resistor for testing for proper fabrication of integrated circuits

    Science.gov (United States)

    Buehler, M. G. (Inventor)

    1985-01-01

    An electrical testing structure and method is described whereby a test structure is fabricated on a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

  2. Thermometric characteristics of some 1/8W carbon resistors in the millikelvin range

    International Nuclear Information System (INIS)

    Radebaugh, R.; Holste, J.C.; Siegwarth, J.D.

    1974-01-01

    Gotch and Awano (Cryogenic Engineering (Tokyo); 8:18 (1973)) have reported on the useful characteristics of 1/8W 100Ω Matsushita carbon resistors (grade ERC-18GK) as thermometers for the region 0.4K and 4.2K. Measurements on the resistance characteristics of this grade of resistors from 11mK to 1K are reported here. Nominal resistances of 56Ω, 68Ω, 82Ω, 100Ω, and 220Ω have been measured. It is found that the 56Ω, 68Ω and 82 Ω resistors make useful thermometers down to at least 11mK. A comparison of the resistance behaviour of units immersed in dilute He 3 -He 4 with those outside the liquid is also made. (author)

  3. Functional Magnetic Stimulation of Inspiratory and Expiratory Muscles in Subjects With Tetraplegia.

    Science.gov (United States)

    Zhang, Xiaoming; Plow, Ela; Ranganthan, Vinoth; Huang, Honglian; Schmitt, Melissa; Nemunaitis, Gregory; Kelly, Clay; Frost, Frederick; Lin, Vernon

    2016-07-01

    Respiratory complications are major causes of morbidity and mortality in persons with a spinal cord injury, partly because of respiratory muscle paralysis. Earlier investigation has demonstrated that functional magnetic stimulation (FMS) can be used as a noninvasive technology for activating expiratory muscles, thus producing useful expiratory functions (simulated cough) in subjects with spinal cord injury. To evaluate the effectiveness of FMS for conditioning inspiratory and expiratory muscles in persons with tetraplegia. A prospective before and after trial. FMS Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, OH. Six persons with tetraplegia. Each subject participated in a 6-week FMS protocol for conditioning the inspiratory and expiratory muscles. A magnetic stimulator was used with the center of a magnetic coil placed at the C7-T1 and T9-T10 spinous processes, respectively. Pulmonary function tests were performed before, during, and after the protocol. Respiratory variables included maximal inspiratory pressure (MIP), inspiratory reserve volume (IRV), peak inspiratory flow (PIF), maximal expiratory pressure (MEP), expiratory reserve volume (ERV), and peak expiratory flow (PEF). After 6 weeks of conditioning, the main outcome measurements (mean ± standard error) were as follows: MIP, 89.6 ± 7.3 cm H2O; IRV, 1.90 ± 0.34 L; PIF, 302.4 ± 36.3 L/min; MEP, 67.4 ± 11.1 cm H2O; ERV, 0.40 ± 0.06 L; and PEF, 372.4 ± 31.9 L/min. These values corresponded to 117%, 107%, 136%, 109%, 130%, and 124% of pre-FMS conditioning values, respectively. Significant improvements were observed in MIP (P = .022), PIF (P = .0001), and PEF (P = .0006), respectively. When FMS was discontinued for 4 weeks, these values showed decreases from their values at the end of the conditioning protocol, which suggests that continual FMS may be necessary to maintain improved respiratory functions. FMS conditioning of the inspiratory and expiratory muscles improved

  4. Cystic lung disease: a comparison of cystic size, as seen on expiratory and inspiratory HRCT scans

    International Nuclear Information System (INIS)

    Lee, Ki Nam; Yoon, Seong Kuk; Nam, Kyung Jin; Choi, Seok Jin; Goo, Jin Mo

    2000-01-01

    To determine the effects of respiration on the size of lung cysts by comparing inspiratory and expiratory high-resolution CT (HRCT) scans. The authors evaluated the size of cystic lesions, as seen on paired inspiratory and expiratory HRCT scans, in 54 patients with Langerhans cell histiocytosis (n = 3), pulmonary lymphangiomyomatosis (n = 4), confluent centrilobular emphysema (n = 9), paraseptal emphysema and bullae (n = 16), cystic bronchiectasis (n = 13), and honeycombing (n = 9). Using paired inspiratory and expiratory HRCT scans obtained at the corresponding anatomic level, a total of 270 cystic lesions were selected simultaneously on the basis of five lesions per lung disease. Changes in lung cyst size observed during respiration were assessed by two radiologists. In a limited number of cases (n = 11), pathologic specimens were obtained by open lung biopsy or lobectomy. All cystic lesions in patients with Langerhans cell histiocytosis, lymphangiomyomatosis, cystic bronchiectasis, honeycombing, and confluent centrilobular emphysema became smaller on expiration, but in two cases of paraseptal emphysema and bullae there was no change. In cases in which expiratory CT scans indicate that cysts have become smaller, cystic lesions may communicate with the airways. To determine whether, for cysts and cystic lesions, this connection does in fact exist, paired inspiratory and expiratory HRCT scans are necessary

  5. Cystic lung disease: a comparison of cystic size, as seen on expiratory and inspiratory HRCT scans

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki Nam; Yoon, Seong Kuk; Nam, Kyung Jin [Donga University College of Medicine, Pusan (Korea, Republic of); Choi, Seok Jin [Inje University College of Medicine, Gimhae (Korea, Republic of); Goo, Jin Mo [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2000-06-01

    To determine the effects of respiration on the size of lung cysts by comparing inspiratory and expiratory high-resolution CT (HRCT) scans. The authors evaluated the size of cystic lesions, as seen on paired inspiratory and expiratory HRCT scans, in 54 patients with Langerhans cell histiocytosis (n = 3), pulmonary lymphangiomyomatosis (n = 4), confluent centrilobular emphysema (n = 9), paraseptal emphysema and bullae (n = 16), cystic bronchiectasis (n = 13), and honeycombing (n = 9). Using paired inspiratory and expiratory HRCT scans obtained at the corresponding anatomic level, a total of 270 cystic lesions were selected simultaneously on the basis of five lesions per lung disease. Changes in lung cyst size observed during respiration were assessed by two radiologists. In a limited number of cases (n = 11), pathologic specimens were obtained by open lung biopsy or lobectomy. All cystic lesions in patients with Langerhans cell histiocytosis, lymphangiomyomatosis, cystic bronchiectasis, honeycombing, and confluent centrilobular emphysema became smaller on expiration, but in two cases of paraseptal emphysema and bullae there was no change. In cases in which expiratory CT scans indicate that cysts have become smaller, cystic lesions may communicate with the airways. To determine whether, for cysts and cystic lesions, this connection does in fact exist, paired inspiratory and expiratory HRCT scans are necessary.

  6. Advanced ceramic composite for high energy resistors : Characterization of electrical and physical properties

    International Nuclear Information System (INIS)

    Farrokh, Fattahi; Navid, Tagizadegan; Naser, Tabatabaei; Ahmad, Rashtehizadeh

    2005-01-01

    There is a need to characterize and apply advanced materials to improve the performance of components used in pulse power systems. One area for innovation is the use of bulk electrically conductive ceramics for non-inductive, high energy and high power electrical resistors. Standard Ceramics Inc. has developed a unique silicon carbide structural ceramic composite which exhibits electrical conductivity. The new, new, conductive, bulk ceramic material has a controlled microstructure, which results in improved homogeneity, making the material suitable for use as a non-inductive, high energy resistor

  7. Method of preparing high-temperature-stable thin-film resistors

    Science.gov (United States)

    Raymond, L.S.

    1980-11-12

    A chemical vapor deposition method for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR) is disclosed. Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor.

  8. Corrections to scaling in random resistor networks and diluted continuous spin models near the percolation threshold.

    Science.gov (United States)

    Janssen, Hans-Karl; Stenull, Olaf

    2004-02-01

    We investigate corrections to scaling induced by irrelevant operators in randomly diluted systems near the percolation threshold. The specific systems that we consider are the random resistor network and a class of continuous spin systems, such as the x-y model. We focus on a family of least irrelevant operators and determine the corrections to scaling that originate from this family. Our field theoretic analysis carefully takes into account that irrelevant operators mix under renormalization. It turns out that long standing results on corrections to scaling are respectively incorrect (random resistor networks) or incomplete (continuous spin systems).

  9. Method of preparing high-temperature-stable thin-film resistors

    International Nuclear Information System (INIS)

    Raymond, L.S.

    1983-01-01

    A chemical vapor deposition method is disclosed for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR). Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor

  10. Effect of diffusion on percolation threshold in thick-film resistors

    International Nuclear Information System (INIS)

    Abdurakhmanov, G.

    2009-01-01

    Resistivity ρ(C) of thick-film resistors doped by metal oxides is simulated as a function of volume content C of the ligature, firing temperature T f and firing time τ. It is proved that the doping of a glass during firing of the thick film resistor is rather uniform. It is shown also, that conductance takes place in the whole volume of the sample, but not through the sole infinite cluster only, even the content of a conductive phase is below than the theoretical percolation threshold value.

  11. Process for obtaining multiple sheet resistances for thin film hybrid microcircuit resistors

    International Nuclear Information System (INIS)

    Norwood, D.P.

    1989-01-01

    A standard thin film circuit containing Ta/sub 2/N (100 ohms/square) resistors is fabricated by depositing on a dielectric substrate successive layers of Ta/sub 2/N, Ti and Pd, with a gold layer to provide conductors. The addition of a few simple photoprocessing steps to the standard TFN manufacturing process enables the formation of Ta/sub 2/N + Ti (10 ohms/square) and Ta/sub 2/N + Ti + Pd (1 ohm/square) resistors in the same otherwise standard thin film circuit structure

  12. Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

    Science.gov (United States)

    Semeriyanov, F.; Saphiannikova, M.; Heinrich, G.

    2009-11-01

    Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

  13. Break-collapse method for resistor networks-renormalization group applications

    International Nuclear Information System (INIS)

    Tsallis, C.; Coniglio, A.; Redner, S.

    1982-01-01

    The break-collapse method recently introduced for the q-state Potts model is adapted for resistor networks. This method greatly simplifies the calculation of the conductance of an arbitrary two-terminal d-dimensional array of conductances, obviating the use of either Kirchhoff's laws or the star-triangle or similiar transformations. Related properties are discussed as well. An illustrative real-space renormalization-group treatment of the random resistor problem on the square lattice is presented; satisfactory results are obtained. (Author) [pt

  14. Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

    International Nuclear Information System (INIS)

    Semeriyanov, F; Saphiannikova, M; Heinrich, G

    2009-01-01

    Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

  15. Deep breathing exercises with positive expiratory pressure at a higher rate improve oxygenation in the early period after cardiac surgery--a randomised controlled trial.

    Science.gov (United States)

    Urell, Charlotte; Emtner, Margareta; Hedenström, Hans; Tenling, Arne; Breidenskog, Marie; Westerdahl, Elisabeth

    2011-07-01

    In addition to early mobilisation, a variety of breathing exercises are used to prevent postoperative pulmonary complications after cardiac surgery. The optimal duration of the treatment is not well evaluated. The aim of this study was to determine the effect of 30 versus 10 deep breaths hourly, while awake, with positive expiratory pressure on oxygenation and pulmonary function the first days after cardiac surgery. A total of 181 patients, undergoing cardiac surgery, were randomised into a treatment group, performing 30 deep breaths hourly the first postoperative days, or into a control group performing 10 deep breaths hourly. The main outcome measurement arterial blood gases and the secondary outcome pulmonary function, evaluated with spirometry, were determined on the second postoperative day. Preoperatively, both study groups were similar in terms of age, SpO(2), forced expiratory volume in 1s and New York Heart Association classification. On the second postoperative day, arterial oxygen tension (PaO(2)) was 8.9 ± 1.7 kPa in the treatment group and 8.1 ± 1.4 kPa in the control group (p = 0.004). Arterial oxygen saturation (SaO(2)) was 92.7 ± 3.7% in the treatment group and 91.1 ± 3.8% in the control group (p = 0.016). There were no differences in measured lung function between the groups or in compliance to the breathing exercises. Compliance was 65% of possible breathing sessions. A significantly increased oxygenation was found in patients performing 30 deep breaths the first two postoperative days compared with control patients performing 10 deep breaths hourly. These results support the implementation of a higher rate of deep breathing exercises in the initial phase after cardiac surgery. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  16. Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Kreitzer, B R; Houck, T L; Luchterhand, O C

    2011-07-19

    This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of {approx}1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm{sup 3} liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by {approx}0.4 C which produces a 0.7% change in resistance. The typical cooling rate is {approx}0.4 C per minute which results in {approx}0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic

  17. Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks

    International Nuclear Information System (INIS)

    Kreitzer, B.R.; Houck, T.L.; Luchterhand, O.C.

    2011-01-01

    This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of ∼1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm 3 liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by ∼0.4 C which produces a 0.7% change in resistance. The typical cooling rate is ∼0.4 C per minute which results in ∼0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still

  18. Changes in forced expiratory volume in 1 second over time in COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Edwards, Lisa D; Scanlon, Paul D

    2011-01-01

    A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce.......A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce....

  19. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Science.gov (United States)

    2010-07-01

    ... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.802 Protection... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of high-voltage circuits; neutral... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating at...

  20. Use of cermet thin film resistors with nitride passivated metal insulator field effect transistor

    Science.gov (United States)

    Brown, G. A.; Harrap, V.

    1971-01-01

    Film deposition of cermet resistors on same chip with metal nitride oxide silicon field effect transistors permits protection of contamination sensitive active devices from contaminants produced in cermet deposition and definition processes. Additional advantages include lower cost, greater reliability, and space savings.

  1. Electrical properties of thick-layer piezo resistors based on Bi2Ru2O7

    International Nuclear Information System (INIS)

    Golonka, L.; Tankiewicz, S.

    1997-01-01

    Piezoelectric effect and electrical properties of thick-layer resistors based on Bi 2 Ru 2 O 7 (on ceramic substrate) have been studied. The influence of selected technological parameters (sintering temperature, chemical composition, heat treatment) on system properties has been estimated. 4 refs, 7 figs

  2. A neutral grounding metallic resistor failure in a 35 kV network

    Directory of Open Access Journals (Sweden)

    Simić Ninoslav

    2011-01-01

    Full Text Available This paper presents the results of observations and measurements of the impedance of the metal resistor for grounding neutral of the 35 kV network, before and after damaging event. The proposed measures are to be taken in order to eliminate a failure in this particular case, as well as the prevention of similar events.

  3. Advanced ceramic composite for high energy resistors. Characterization of electrical and physical properties

    International Nuclear Information System (INIS)

    Farrokh, Fattahi; Navid, Tagizadegan; Naser, Tabatabaei

    2005-01-01

    Full text : There is a need to characterize and apply advanced materials to improve the performance of components used in pulse power systems. One area for innovation is the use of bulk electrically conductive ceramics for non-inductive, high energy and high power electrical resistors. Standard Ceramics, Inc. has developed a unique silicon carbide structural ceramic composite which exhibits electrical conductivity. The new conductive bulk ceramic material has a controlled microstructure, which results an improved homogeneity, making the material suitable for use as a non-inductive, high energy resistor. The new material has higher density, highee peak of temperature limit and greater physical strength compared with bulk ceramics currently used for pulsed power resistors. This paper describes characterization of the material's physical and electrical properties and relates them to improvements in low-power density, as compared to existing components would be expected and derived from specific properties such as good thermal conductivity, high strength, thermal shock resistance and high temperature capability. The bulk resistor approach that weas proposed offers high reliability through better mechanical properties and simplicity of construction

  4. The Transition from Traditional to Whole Language Instruction: A Continuum from Reformers to Resistors.

    Science.gov (United States)

    Schweiker, Karyn E.; Barksdale-Ladd, Mary Alice

    Factors that influenced teachers to become reformers, reviewers, or resistors to whole language were investigated with specific examination of school culture. In this study three transitioning school sites were selected on the basis of their similarity in staffing and student size. Participants from each school involved three to four classroom…

  5. A study of cross-bridge kelvin resistor structures for reliable measurement of low contact resistances

    NARCIS (Netherlands)

    Stavitski, N.; Klootwijk, J.H.; van Zeijl, H.W.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2008-01-01

    The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (�?c) have been extensively discussed during last few decades and the minimum of the �?c value, which could be accurately extracted, was

  6. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  7. Processing, microstructure, and electric properties of buried resistors in low-temperature co-fired ceramics

    International Nuclear Information System (INIS)

    Yang, Pin; Rodriguez, Mark A.; Kotula, Paul; Miera, Brandon K.; Dimos, Duane

    2001-01-01

    The electrical properties of ruthenium oxide based devitrifiable resistors embedded within low-temperature co-fired ceramics were investigated from -100 o C to 100 o C. Special attention was given to the processing conditions and their effects on resistance and temperature coefficient of resistance (TCR). Results indicate that within this temperature range the conductance for these buried resistors is limited by tunneling of charge carriers through the thin glass layer between ruthenium oxide particles. A modified version of the tunneling barrier model is proposed to account for the microstructure ripening observed during thermal processing. The model parameters determined from curve fitting show that charging energy (i.e., the energy required for a charge carrier to tunnel through the glass barrier) is strongly dependent on particle size and particle--particle separation between ruthenium oxide grains. Initial coarsening of ruthenium oxide grains was found to reduce the charging energy and lower the resistance. However, when extended ripening occurs, the increase in particle--particle separation increases the charging energy, reduces the tunneling probability and gives rise to a higher resistance. The tradeoff between these two effects results in an optimum microstructure with a minimum resistance and TCR. Furthermore, the TCR of these buried resistors has been shown to be governed by the magnitude of the charging energy. Model parameters determined by our analysis appear to provide quantitative physical interpretations to the microstructural changes in the resistor, which in turn, are controlled by the processing conditions

  8. Cosmic Ray Measurements by Scintillators with Metal Resistor Semiconductor Avalanche Photo Diodes

    Science.gov (United States)

    Blanco, Francesco; La Rocca, Paola; Riggi, Francesco; Akindinov, Alexandre; Mal'kevich, Dmitry

    2008-01-01

    An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

  9. Ni-Cr thin film resistor fabrication for GaAs monolithic microwave integrated circuits

    International Nuclear Information System (INIS)

    Vinayak, Seema; Vyas, H.P.; Muraleedharan, K.; Vankar, V.D.

    2006-01-01

    Different Ni-Cr alloys were sputter-deposited on silicon nitride-coated GaAs substrates and covered with a spin-coated polyimide layer to develop thin film metal resistors for GaAs monolithic microwave integrated circuits (MMICs). The contact to the resistors was made through vias in the polyimide layer by sputter-deposited Ti/Au interconnect metal. The variation of contact resistance, sheet resistance (R S ) and temperature coefficient of resistance (TCR) of the Ni-Cr resistors with fabrication process parameters such as polyimide curing thermal cycles and surface treatment given to the wafer prior to interconnect metal deposition has been studied. The Ni-Cr thin film resistors exhibited lower R S and higher TCR compared to the as-deposited Ni-Cr film that was not subjected to thermal cycles involved in the MMIC fabrication process. The change in resistivity and TCR values of Ni-Cr films during the MMIC fabrication process was found to be dependent on the Ni-Cr alloy composition

  10. Determining the influence of temperature on various types of standard resistors

    CSIR Research Space (South Africa)

    Marais, EL

    2006-10-01

    Full Text Available Types of Standard Resistors Speaker / Author: E.L. Marais CSIR National Metrology Laboratory PO Box 395, Pretoria, 0001, South Africa Email: elmarais@csir.co.za Phone: 012 841 3013 Fax: 012 841 2131 Abstract The temperature coefficient...

  11. [A comparative study between inflation and deflation pressure-volume curve in determining the optimal positive end-expiratory pressure].

    Science.gov (United States)

    Gang, Li; Sun, Xiao-yi; Xu, Jin-quan; Zhang, Xin-li; Kou, Lu-xin; Jiang, Zhi-hong; Zhang, Lei

    2012-02-01

    To determine the optimal positive end-expiratory pressure (PEEP) according to inflation and deflation pressure-volume curve (P-V curve) in patients with acute respiratory distress syndrome (ARDS). ARDS models were reproduced in 20 dogs, and they were randomly divided into two groups. In both groups, Levenberg-Marquardt iterative algorithm was employed using software to explore parameters fitting with Boltzmann formula, by which the real inflection point of pressure (Pinf d) in deflation limb or lower inflection point pressure (PLip) in inflation limb on P-V curve were defined. For the control group (inflation curve) P-V curve of PLip + 2 cm H(2)O [1 cm H(2)O = 0.098 kPa] was applied as the best PEEP value. In the experimental group (deflation curve) the Pinf d was taken as the best PEEP value. The heart rate (HR), blood pressure (BP), fingertip pulse oxygen saturation [SpO(2)], static lung compliance (Cst), arterial partial pressure of oxygen [PaO(2)] and arterial partial pressure of carbon dioxide [PaCO(2)] were monitored at 0, 2, 6, 12, 24 and 48 hours. Oxygenation index increased significantly both in control and experimental groups. In experimental group, oxygenation index (mm Hg, 1 mm Hg = 0.133 kPa) of 12, 24 and 48 hours was respectively significantly higher than that of the control group (12 hours: 177.63 ± 8.94 vs. 165.60 ± 8.90, 24 hours: 194.19 ± 10.67 vs. 168.70 ± 10.60, 48 hours: 203.15 ± 13.21 vs. 171.26 ± 9.21, all P deflation P-V curve was better than that of inflation curve.

  12. Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors

    International Nuclear Information System (INIS)

    Gouveia-Caridade, Carla; Soares, David M.; Liess, Hans-Dieter; Brett, Christopher M.A.

    2008-01-01

    The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 Ω and 2.0 kΩ nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investigated 2 Ω carbon film resistors. Cyclic voltammetry was performed in acetate buffer and phosphate buffer saline electrolytes and the kinetic parameters of the model redox system Fe(CN) 6 3-/4- obtained. The 1.5 Ω resistor electrodes show the best properties for sensor development with wide potential windows, similar electrochemical behaviour to those of 2 Ω and close-to-reversible kinetic parameters after electrochemical pre-treatment. The 15 and 140 Ω resistor electrodes show wide potential windows although with slower kinetics, whereas the 2.0 kΩ resistor electrodes show poor cyclic voltammetric profiles even after pre-treatment. Electrochemical impedance spectroscopy related these findings to the interfacial properties of the electrodes. Microstructural and morphological studies were carried out using contact mode Atomic Force Microscopy (AFM), Confocal Raman spectroscopy and X-ray diffraction. AFM showed more homogeneity of the films with lower nominal resistances, related to better electrochemical characteristics. X-ray diffraction and Confocal Raman spectroscopy indicate the existence of a graphitic structure in the carbon films

  13. Measurements of fuse and resistor characteristics for multi-megajoule capacitor bank application

    International Nuclear Information System (INIS)

    McDonald, K.F.; Smith, T.; Golden, J.; Conley, B.

    1986-01-01

    Experimental tests have been conducted on commercially available fuses and resistors under fast high voltage pulsed (10 μsec) conditions to determine their ability to protect capacitor bank components during faults. NRL's Modified Betatron Accelerator uses two multi-megajoule capacitor banks to power the toroidal and betatron magnetic field coils. The expensive high energy density capacitors in these banks must be protected from excessive peak current, voltage reversal, or charging beyond their electrical ratings in the occurrence of a fault. Adequate protection can be obtained with fuses and resistors in series with each parallel connected capacitor. The fuses must open reliably and hold off high voltage D.C. (10 - 20 kV), and the resistors must conduct high current and di/dt without failing from energy deposition or magnetic forces. The performance of the commercial fuses is well documented at low AC frequencies and currents (60 Hz/100 A) but data was not previously available for the fast high current pulsed conditions that prevail under actual fault conditions. A 20 kV 200 kJ, low inductance capacitor bank and ignitron switch were used to conduct the experiments. Peak currents in the fuses were approximately 170 kA at t - 6.5 μs. The final fuse hold-off voltage exceeded 8 kV. Currents in the resistors ranged from - 20 - 40 kA per resistor. The experimental results have been compared to the manufacturers data from minimum melt and maximum let-through and to exploding bridge wire computer models

  14. Modeling of three-dimensional diffusible resistors with the one-dimensional tube multiplexing method

    International Nuclear Information System (INIS)

    Gillet, Jean-Numa; Degorce, Jean-Yves; Meunier, Michel

    2009-01-01

    Electronic-behavior modeling of three-dimensional (3D) p + -π-p + and n + -ν-n + semiconducting diffusible devices with highly accurate resistances for the design of analog resistors, which are compatible with the CMOS (complementary-metal-oxide-semiconductor) technologies, is performed in three dimensions with the fast tube multiplexing method (TMM). The current–voltage (I–V) curve of a silicon device is usually computed with traditional device simulators of technology computer-aided design (TCAD) based on the finite-element method (FEM). However, for the design of 3D p + -π-p + and n + -ν-n + diffusible resistors, they show a high computational cost and convergence that may fail with fully non-separable 3D dopant concentration profiles as observed in many diffusible resistors resulting from laser trimming. These problems are avoided with the proposed TMM, which divides the 3D resistor into one-dimensional (1D) thin tubes with longitudinal axes following the main orientation of the average electrical field in the tubes. The I–V curve is rapidly obtained for a device with a realistic 3D dopant profile, since a system of three first-order ordinary differential equations has to be solved for each 1D multiplexed tube with the TMM instead of three second-order partial differential equations in the traditional TCADs. Simulations with the TMM are successfully compared to experimental results from silicon-based 3D resistors fabricated by laser-induced dopant diffusion in the gaps of MOSFETs (metal-oxide-semiconductor field-effect transistors) without initial gate. Using thin tubes with other shapes than parallelepipeds as ring segments with toroidal lateral surfaces, the TMM can be generalized to electronic devices with other types of 3D diffusible microstructures

  15. Au/Ti resistors used for Nb/Pb-alloy Josephson junctions. I. Electrical stability

    International Nuclear Information System (INIS)

    Murakami, M.; Alessandrini, E.I.; Kim, K.K.

    1984-01-01

    Bilayered Au/Ti films are very attractive for use as resistor materials of experimental Nb/Pb-alloy Josephson junction devices. In order to predict the electrical stability of the Au/Ti resistors during storage at room temperature, changes in microstructure and electrical resistivity of Ti and Au/Ti films during isothermal annealing at temperatures ranging from 298--473 K were studied using transmission electron microscopy, x-ray diffraction, and electrical measurements. Growth of Ti grains during annealing was observed in these films. The activation energy for the grain growth was determined to be 1.51 eV. Decreases in the sheet resistance measured at 4.2 K were observed at the early stages of isothermal annealing. By analyzing the annealing temperature dependence of rates of resistance changes, the activation energy of 1.49 eV was obtained. This energy value is very close to that obtained for the grain growth and, therefore, one of the main causes in the resistance decrease is believed to be due to the growth of Ti grains. Based on the present results, a model to predict the electrical resistance change for the Au/Ti films during storage at room temperature was established. The model predicted that change in the resistance can be significantly reduced by preannealing the resistors at an elevated temperature. The prediction was supported by the experiment and an excellent quantitative agreement between measured resistance values and those predicted by the model was obtained. Based on this model, the change was predicted to be -1.5% after about 3 years at room temperature, if the resistors were preannealed at 353 K for 10 h. This resistor stability is satisfactory for designing logic and memory circuits of Josephson devices, and it can be increased simply by preannealing for longer times at 353 K

  16. Test of the Starling resistor model in the human upper airway during sleep.

    Science.gov (United States)

    Wellman, Andrew; Genta, Pedro R; Owens, Robert L; Edwards, Bradley A; Sands, Scott A; Loring, Stephen H; White, David P; Jackson, Andrew C; Pedersen, Ole F; Butler, James P

    2014-12-15

    The human pharyngeal airway during sleep is conventionally modeled as a Starling resistor. However, inspiratory flow often decreases with increasing effort (negative effort dependence, NED) rather than remaining fixed as predicted by the Starling resistor model. In this study, we tested a major prediction of the Starling resistor model--that the resistance of the airway upstream from the site of collapse remains fixed during flow limitation. During flow limitation in 24 patients with sleep apnea, resistance at several points along the pharyngeal airway was measured using a pressure catheter with multiple sensors. Resistance between the nose and the site of collapse (the upstream segment) was measured before and after the onset of flow limitation to determine whether the upstream dimensions remained fixed (as predicted by the Starling resistor model) or narrowed (a violation of the Starling resistor model). The upstream resistance from early to mid inspiration increased considerably during flow limitation (by 35 ± 41 cmH2O · liter(-1) · s(-1), P < 0.001). However, there was a wide range of variability between patients, and the increase in upstream resistance was strongly correlated with the amount of NED (r = 0.75, P < 0.001). Therefore, patients with little NED exhibited little upstream narrowing (consistent with the Starling model), and patients with large NED exhibited large upstream narrowing (inconsistent with the Starling model). These findings support the idea that there is not a single model of pharyngeal collapse, but rather that different mechanisms may dominate in different patients. These differences could potentially be exploited for treatment selection. Copyright © 2014 the American Physiological Society.

  17. THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY

    Science.gov (United States)

    THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY. William F. McDonnell Human Studies Division, NHEERL, U.S. Environmental Protection Agency, RTP, NC 27711. Short-term exposure to ozone results in a neurally-mediated decrease in the ab...

  18. Pharmacologic Interventions to Improve Splanchnic Oxygenation During Ventilation with Positive End-Expiratory Pressure

    NARCIS (Netherlands)

    Fournell, A.; Scheeren, T. W. L.; Picker, O.; Schwarte, L. A.; Wolf, M; Bucher, HU; Rudin, M; VanHuffel, S; Wolf, U; Bruley, DF; Harrison, DK

    2012-01-01

    Mechanical ventilation with positive end-expiratory pressure (PEEP) is an indispensable tool in the management of respiratory failure to preserve or improve lung function and systemic oxygenation. However, PEEP per se may also, as has been shown in experimental animals, impair regional

  19. Exogenous stimuli and circadian peak expiratory flow variation in allergic asthmatic children

    NARCIS (Netherlands)

    Meijer, G. G.; Postma, D. S.; van der Heide, S.; de Reus, D. M.; Roorda, R. J.; Koëter, G. H.; van Aalderen, W. M.

    1996-01-01

    The influence of exogenous factors in the home on the circadian variation of airway obstruction has not been fully assessed in children with asthma. The aim of the present study was to investigate the contribution of exogenous stimuli to the degree of peak expiratory flow (PEF) variability during 24

  20. Seasonal variations in house dust mite influence the circadian peak expiratory flow amplitude

    NARCIS (Netherlands)

    Postma, DS; vanderHeide, S; deReus, DM; Koeter, GH; vanAalderen, WMC; Meijer, G.

    1996-01-01

    The aim of the study was to investigate whether seasonal differences in house dust mite (HDM) allergen exposure influence the circadian peak expiratory flow (PEF) amplitude in asthmatic children. Asthmatic children (n = 25) with a solitary allergy to HDM were studied in spring and in autumn. All

  1. Exogenous stimuli and circadian peak expiratory flow variation in allergic asthmatic children

    NARCIS (Netherlands)

    Postma, DS; VanderHeide, S; DeReus, DM; Koeter, GH; VanAalderen, WMC; Meijer, G.

    The influence of exogenous factors in the home on the circadian variation of airway obstruction has not been fully assessed in children with asthma. The aim of the present study was to investigate the contribution of exogenous stimuli to the degree of peak expiratory flow (PEF) variability during 24

  2. Dead space and slope indices from the expiratory carbon dioxide tension-volume curve

    NARCIS (Netherlands)

    A.H. Kars (Alice); J.M. Bogaard (Jan); Th. Stijnen (Theo); J. de Vries; A.F.M. Verbraak (Anton); C. Hilvering

    1997-01-01

    textabstractThe slope of phase 3 and three noninvasively determined dead space estimates derived from the expiratory carbon dioxide tension (PCO2) versus volume curve, including the Bohr dead space (VD,Bohr), the Fowler dead space (VD,Fowler) and pre-interface expirate

  3. Hyperinflation and intrinsic positive end-expiratory pressure: less room to breathe.

    Science.gov (United States)

    Krieger, Bruce P

    2009-01-01

    Clinically, the symptoms and limited exercise capabilities of patients with chronic obstructive pulmonary disease (COPD) correlate better with changes in lung volumes than with airflow measurements. The realization of the clinical importance of hyperinflation has been overshadowed for decades by the use of forced expiratory volume during 1 s (FEV(1)) and the ratio of the FEV(1) to the forced expiratory vital capacity (FEV(1)/FVC) to categorize the severity and progression of COPD. Hyperinflation is defined as an elevation in the end-expiratory lung volume or functional residual capacity. When severe hyperinflation encroaches upon inspiratory capacity and limits vital capacity, it results in elevated intrinsic positive end-expiratory pressure (PEEPi) that places the diaphragm at a mechanical disadvantage and increases the work of breathing. Severe hyperinflation is the major physiologic cause of the resulting hypercarbic respiratory failure and patients' inability to transition (i.e. wean) from mechanical ventilatory support to spontaneous breathing. This paper reviews the basic physiologic principles of hyperinflation and its clinical manifestations as demonstrated by PEEPi. Also reviewed are the adverse effects of hyperinflation and PEEPi in critically ill patients with COPD, and methods for minimizing or counterbalancing these effects. Copyright 2009 S. Karger AG, Basel.

  4. Changes in forced expiratory volume in 1 second over time in COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Edwards, Lisa D; Scanlon, Paul D

    2011-01-01

    A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce....

  5. The resistance changes of carbon and metal oxide film resistors by irradiation of 60Co γ rays

    International Nuclear Information System (INIS)

    Okamoto, Shinichi; Fujino, Takahiro; Furuta, Junichiro; Yoshida, Toshio

    1979-01-01

    The resistance changes of glass-sealed deposited-carbon-film and carbon-coated-film resitors and metal oxide glazed resistors made in USA were studied by gamma-ray irradiation. (1) The resistances of deposited-carbon-film resistors of 50, 100 and 200 megohm did not change by irradiation of gamma rays up to 1.9 x 10 9 R. (2) The carbon-coated-film resistors of 100, 1000, 10000 and 100000 megohm had negative resistance changes by irradiation of gamma rays up to 9.9 x 10 8 R. (3) The resistances of metal oxide glazed resistors of 100, 1000 and 10000 megohm did not change by irradiation of gamma rays up to 8.8 x 10 8 R. When radiation monitoring instruments with hi-meg resistors are used in a gamma field with high intensity, the resistors must not be exposed to gamma rays with high doses, or the resistors which do not change by gamma-ray irradiation must be selected. (author)

  6. Effects of dorsal and lateral decubitus on peak expiratory flow in healthy subjects

    Directory of Open Access Journals (Sweden)

    Heloisa H. Gianinis

    2013-10-01

    Full Text Available BACKGROUND: One of the measures of the pulmonary function is the peak expiratory flow (PEF that can be defined as the major flow obtained in an expiratory pressure after a complete inspiration to the level of the total lung capacity. This measure depends on the effort and strength of expiratory muscles, the airway diameter and the lung volume. OBJECTIVE: To compare the results of the peak expiratory flow in healthy male and female obtained in a seated position and dorsal decubitus (DD, right lateral decubitus (RLD and left lateral decubitus (LLD. METHOD: Thirty young subjects with mean age 22.7 years, healthy and non-smokers were included at the study, 15 of male sex. They did spirometry and IPAQ questionnaire to check the normal pulmonary function and physical activity level. The measures of PEF were performed in four positions, being performed 3 measures in which position, in a random order. Statistical analysis was performed according to Student's t test, with significance level set at 5%. RESULTS: There was a difference between the values obtained in sitting position(481±117.1 L/min with DD(453.2±116.3 L/min and RLD (454±112.9 L/min (p<0.05, however, did not find a significant difference between the sitting position and LLD (469±83 L/min. CONCLUSIONS: Body position affects the values of PEF, with decreasing values in DD and RLD. The LLD can be an alternative to optimize the expiratory flow in situations of constraint to the sitting position.

  7. Effects of respiratory rate, plateau pressure, and positive end-expiratory pressure on PaO2 oscillations after saline lavage.

    Science.gov (United States)

    Baumgardner, James E; Markstaller, Klaus; Pfeiffer, Birgit; Doebrich, Marcus; Otto, Cynthia M

    2002-12-15

    One of the proposed mechanisms of ventilator-associated lung injury is cyclic recruitment of atelectasis. Collapse of dependent lung regions with every breath should lead to large oscillations in PaO2 as shunt varies throughout the respiratory cycle. We placed a fluorescence-quenching PO2 probe in the brachiocephalic artery of six anesthetized rabbits after saline lavage. Using pressure-controlled ventilation with oxygen, ventilator settings were varied in random order over three levels of positive end-expiratory pressure (PEEP), respiratory rate (RR), and plateau pressure minus PEEP (Delta). Dependence of the amplitude of PaO2 oscillations on PEEP, RR, and Delta was modeled by multiple linear regression. Before lavage, arterial PO2 oscillations varied from 3 to 22 mm Hg. After lavage, arterial PO2 oscillations varied from 5 to 439 mm Hg. Response surfaces showed markedly nonlinear dependence of amplitude on PEEP, RR, and Delta. The large PaO2 oscillations observed provide evidence for cyclic recruitment in this model of lung injury. The important effect of RR on the magnitude of PaO2 oscillations suggests that the static behavior of atelectasis cannot be accurately extrapolated to predict dynamic behavior at realistic breathing frequencies.

  8. Measurement of small ion beams by thermal ionisation mass spectrometry using new 1013 Ohm resistors

    International Nuclear Information System (INIS)

    Koornneef, J.M.; Bouman, C.; Schwieters, J.B.; Davies, G.R.

    2014-01-01

    Highlights: • First data are presented using 10 13 Ohm resistors connected to Faraday collectors. • 5 prototype 10 13 Ohm resistors were installed in a TRITON-Plus TIMS. • Performance was tested by measuring Sr and Nd isotope ratios on  13 Ohm resistors perform better than ion counting and 10 11 Ohm resistors. • Fourth decimal variability can be resolved for Nd isotope ratios on 10 pg samples. - Abstract: We tested 5 newly manufactured – prototype – 10 13 Ohm resistors in the feedback loop of Faraday cup amplifiers to measure small ion beams by Thermal Ionisation Mass Spectrometry (TIMS). The high Ohmic resistors installed in the TRITON Plus at the VU University Amsterdam theoretically have 10 times lower noise levels relative to the default 10 11 Ohm resistors. To investigate the precision and accuracy of analyses using these new amplifiers we measured Sr and Nd isotopes of reference standards at a range of ion currents (3.2 × 10 −16 to 1 × 10 −12 A, corresponding to intensities of 32 μV to 100 mV on a default 10 11 Ohm amplifier) and on small amounts of material (100 and 10 pg). Internal precision and external reproducibility for Sr and Nd isotope ratios are both better when collected on 10 13 compared 10 12 Ohm resistors and to the default 10 11 Ohm resistors. At an 87 Sr ion current of 3 × 10 −14 A (3 mV on a 10 11 Ohm amplifier) the internal precision (2 SE) of 87 Sr/ 86 Sr is 5 times better for 10 13 Ohm resistors compared to 10 11 Ohm resistors. The external reproducibility (2 SD) at this beam intensity is 9 times better. Multiple 100 and 10 pg Sr standards, ran to exhaustion, yielded low 87 Sr/ 86 Sr compared to the long term average (e.g. 10 pg average = 0.710083 ± 164 (n = 11) instead of 0.710244 ± 12, n = 73). The average off-set for 10 pg standards can be explained by a loading blank contribution of 1.3 pg. In contrast, Nd data on 100 pg and 10 pg samples are accurate suggesting that Nd loading blanks do not compromise the

  9. Liquid breathing - Prevention of pulmonary arterial-venous shunting during acceleration.

    Science.gov (United States)

    Sass, D. J.; Ritman, E. L.; Caskey, P. E.; Banchero, N.; Wood, E. H.

    1972-01-01

    Dependent pulmonary atelectasis, arterial-venous shunting, and downward displacement of the heart caused by the gravitational-inertial force environment were prevented in dogs breathing oxygenated liquid fluorocarbon in a whole-body water-immersion respirator. Partial closure of the major airways during part of the expiratory phase of liquid respiration was a significant problem initially but was minimized in subsequent studies.

  10. Effects of positive end-expiratory pressure titration and recruitment maneuver on lung inflammation and hyperinflation in experimental acid aspiration-induced lung injury.

    Science.gov (United States)

    Ambrosio, Aline M; Luo, Rubin; Fantoni, Denise T; Gutierres, Claudia; Lu, Qin; Gu, Wen-Jie; Otsuki, Denise A; Malbouisson, Luiz M S; Auler, Jose O C; Rouby, Jean-Jacques

    2012-12-01

    In acute lung injury positive end-expiratory pressure (PEEP) and recruitment maneuver are proposed to optimize arterial oxygenation. The aim of the study was to evaluate the impact of such a strategy on lung histological inflammation and hyperinflation in pigs with acid aspiration-induced lung injury. Forty-seven pigs were randomly allocated in seven groups: (1) controls spontaneously breathing; (2) without lung injury, PEEP 5 cm H2O; (3) without lung injury, PEEP titration; (4) without lung injury, PEEP titration + recruitment maneuver; (5) with lung injury, PEEP 5 cm H2O; (6) with lung injury, PEEP titration; and (7) with lung injury, PEEP titration + recruitment maneuver. Acute lung injury was induced by intratracheal instillation of hydrochloric acid. PEEP titration was performed by incremental and decremental PEEP from 5 to 20 cm H2O for optimizing arterial oxygenation. Three recruitment maneuvers (pressure of 40 cm H2O maintained for 20 s) were applied to the assigned groups at each PEEP level. Proportion of lung inflammation, hemorrhage, edema, and alveolar wall disruption were recorded on each histological field. Mean alveolar area was measured in the aerated lung regions. Acid aspiration increased mean alveolar area and produced alveolar wall disruption, lung edema, alveolar hemorrhage, and lung inflammation. PEEP titration significantly improved arterial oxygenation but simultaneously increased lung inflammation in juxta-diaphragmatic lung regions. Recruitment maneuver during PEEP titration did not induce additional increase in lung inflammation and alveolar hyperinflation. In a porcine model of acid aspiration-induced lung injury, PEEP titration aimed at optimizing arterial oxygenation, substantially increased lung inflammation. Recruitment maneuvers further improved arterial oxygenation without additional effects on inflammation and hyperinflation.

  11. Intraoperative and postoperative evaluation of low tidal volume combined with low-level positive end-expiratory pressure ventilation in laparoscopic surgery in elderly patients

    Directory of Open Access Journals (Sweden)

    Ye-Qiu Li

    2016-01-01

    Full Text Available Objective: To evaluate intraoperative and postoperative condition of low tidal volume combined with low-level positive end-expiratory pressure ventilation in laparoscopic surgery in elderly patients. Methods: A total of 176 cases of elderly patients (more than 60 years old receiving laparoscopic surgery in our hospital from July 2013 to July 2015 were selected as research subjects and randomly divided into observation group and control group, each group included 88 cases, control group received conventional ventilation strategy, observation group received low tidal volume combined with low-level positive end-expiratory pressure ventilation strategy, and then levels of hemodynamic indexes, respiratory mechanical indexes, serology indexes and cerebral vessel related indexes, etc of two groups were compared. Results: Intraoperative and postoperative heart rate and mean arterial pressure levels of observation group were lower than those of control group, arterial partial pressure of oxygen and oxygenation index levels were higher than those of control group and differences had statistical significance (P<0.05; intraoperative APIP and Pplat values of observation group were lower than those of control group, Cs value was higher than that of control group and differences had statistical significance (P<0.05; intraoperative and postoperative serum IL-8 and TNF-α levels of observation group were lower than those of control group, IL-10 level was higher than that of control group and differences had statistical significance (P<0.05; intraoperative and postoperative PjvO2, SjvO2 and CjvO2 levels of observation group were higher than those of control group, Da-jvO2 level was lower than that of control group and differences had statistical significance (P<0.05. Conclusions: When elderly patients receive laparoscopic surgery, the use of low tidal volume combined with low-level positive end-expiratory pressure ventilation strategy can stabilize hemodynamic

  12. Interaction between intra-abdominal pressure and positive-end expiratory pressure

    Directory of Open Access Journals (Sweden)

    Jamili Anbar Torquato

    2009-02-01

    Full Text Available OBJECTIVE: The aim of this study was to quantify the interaction between increased intra-abdominal pressure and Positive-End Expiratory Pressure. METHODS: In 30 mechanically ventilated ICU patients with a fixed tidal volume, respiratory system plateau and abdominal pressure were measured at a Positive-End Expiratory Pressure level of zero and 10 cm H2O. The measurements were repeated after placing a 5 kg weight on the patients' belly. RESULTS: After the addition of 5 kg to the patients' belly at zero Positive-End Expiratory Pressure, both intra-abdominal pressure (p<0.001 and plateau pressures (p=0.005 increased significantly. Increasing the Positive-End Expiratory Pressure levels from zero to 10 cm H2O without weight on the belly did not result in any increase in intra-abdominal pressure (p=0.165. However, plateau pressures increased significantly (p< 0.001. Increasing Positive-End Expiratory Pressure from zero to 10 cm H2O and adding 5 kg to the belly increased intra-abdominal pressure from 8.7 to 16.8 (p<0.001 and plateau pressure from 18.26 to 27.2 (p<0.001. Maintaining Positive-End Expiratory Pressure at 10 cm H2O and placing 5 kg on the belly increased intra-abdominal pressure from 12.3 +/- 1.7 to 16.8 +/- 1.7 (p<0.001 but did not increase plateau pressure (26.6+/-1.2 to 27.2 +/-1.1 -p=0.83. CONCLUSIONS: The addition of a 5kg weight onto the abdomen significantly increased both IAP and the airway plateau pressure, confirming that intra-abdominal hypertension elevates the plateau pressure. However, plateau pressure alone cannot be considered a good indicator for the detection of elevated intra-abdominal pressure in patients under mechanical ventilation using PEEP. In these patients, the intra-abdominal pressure must also be measured.

  13. Applicability of the lattice Boltzmann method to determine the ohmic resistance in equivalent resistor connections

    Science.gov (United States)

    Espinoza-Andaluz, Mayken; Barzola, Julio; Guarochico-Moreira, Víctor H.; Andersson, Martin

    2017-12-01

    Knowing the ohmic resistance in the materials allow to know in advance its electrical behavior when a potential difference is applied, and therefore the prediction of the electrical performance can be achieved in a most certain manner. Although the Lattice Boltzmann method (LBM) has been applied to solve several physical phenomena in complex geometries, it has only been used to describe the fluid phase, but applicability studies of LBM on the solid-electric-conducting material have not been carried out yet. The purpose of this paper is to demonstrate the accuracy of calculating the equivalent resistor connections using LBM. Several series and parallel resistor connections are effected. All the computations are carried out with 3D models, and the domain materials are designed by the authors.

  14. 4-bit digital to analog converter using R-2R ladder and binary weighted resistors

    Science.gov (United States)

    Diosanto, J.; Batac, M. L.; Pereda, K. J.; Caldo, R.

    2017-06-01

    The use of a 4-bit digital-to-analog converter using two methods; Binary Weighted Resistors and R-2R Ladder is designed and presented in this paper. The main components that were used in constructing both circuits were different resistor values, operational amplifier (LM741) and single pole double throw switches. Both circuits were designed using MULTISIM software to be able to test the circuit for its ideal application and FRITZING software for the layout designing and fabrication to the printed circuit board. The implementation of both systems in an actual circuit benefits in determining and comparing the advantages and disadvantages of each. It was realized that the binary weighted circuit is more efficient DAC, having lower percentage error of 0.267% compared to R-2R ladder circuit which has a minimum of percentage error of 4.16%.

  15. Sizing of the Series Dynamic Breaking Resistor in a Doubly Fed Induction Generator Wind Turbine

    DEFF Research Database (Denmark)

    Soliman, Hammam; Wang, Huai; Zhou, Dao

    2014-01-01

    This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter and the maxi......This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter...... and the maximum allowable voltage of the stator. Then the impact of the SDBR value on the rotor current, stator voltage, DC-link voltage, reactive power capability and introduced power loss during voltage sag operation is evaluated by simulation. The presented study enables a trade-off sizing of the SDBR among...

  16. Conductivity of a square-lattice bond-mixed resistor network

    International Nuclear Information System (INIS)

    Costa, U.M.S.; Tsallis, C.; Schwaccheim, G.

    1985-01-01

    Within a real-space renormalization-group framework based on self-dual clusters, the conductivity of a square-lattice quenched bond-random resistor network is calculated, the conductance on each bond being g 1 or g 2 with probabilities (1-p) and p respectively. The group recovers several already known exact results (including slopes), and is consequently believed to be numerically quite reliable for almost all values of p, and all ratios g 1 /g 2 (in particular, g 1 =0 and g 1 =infinite with finite g 2 respectively correspond to the insulator-resitor and superconductor-resistor mixtures). In addition to that, an heuristic analytic expression is proposed for the conductivity which is believed to be a quite satisfactory approximation everywhere not too close to the percolation point. (Author) [pt

  17. Update for nurse anesthetists. The Starling resistor: a model for explaining and treating obstructive sleep apnea.

    Science.gov (United States)

    Stalford, Catherine B

    2004-04-01

    Recent epidemiological research places the incidence of obstructive sleep apnea as high as 16% in the general population. Serious postoperative respiratory complications and death have been reported in this population. Anesthetic drugs contribute to these complications secondary to acute and residual influences on the complex orchestration of airway muscles and reflexes involved in airway patency. The Starling resistor model is a theoretical model that has application in explaining upper airway dynamics and the treatment and management of obstructive sleep apnea. The model postulates the oropharynx as a collapsible tube. The oropharynx remains open or partially or completely closed as a result of pressure upstream at the nose and mouth, pressure downstream at the trachea and below, or tissue pressure surrounding the oropharynx. This AANA Journal course provides an overview of the Starling resistor model, its application to obstructive sleep apnea, and preoperative and postoperative anesthetic considerations.

  18. Current flow in random resistor networks: the role of percolation in weak and strong disorder.

    Science.gov (United States)

    Wu, Zhenhua; López, Eduardo; Buldyrev, Sergey V; Braunstein, Lidia A; Havlin, Shlomo; Stanley, H Eugene

    2005-04-01

    We study the current flow paths between two edges in a random resistor network on a L X L square lattice. Each resistor has resistance e(ax) , where x is a uniformly distributed random variable and a controls the broadness of the distribution. We find that: (a) The scaled variable u identical with u congruent to L/a(nu) , where nu is the percolation connectedness exponent, fully determines the distribution of the current path length l for all values of u . For u > 1, the behavior corresponds to the weak disorder limit and l scales as l approximately L, while for u < 1 , the behavior corresponds to the strong disorder limit with l approximately L(d(opt) ), where d(opt) =1.22+/-0.01 is the optimal path exponent. (b) In the weak disorder regime, there is a length scale xi approximately a(nu), below which strong disorder and critical percolation characterize the current path.

  19. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite.

    Science.gov (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J

    2017-07-01

    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  20. Nonlinear random resistor diode networks and fractal dimensions of directed percolation clusters.

    Science.gov (United States)

    Stenull, O; Janssen, H K

    2001-07-01

    We study nonlinear random resistor diode networks at the transition from the nonpercolating to the directed percolating phase. The resistor-like bonds and the diode-like bonds under forward bias voltage obey a generalized Ohm's law V approximately I(r). Based on general grounds such as symmetries and relevance we develop a field theoretic model. We focus on the average two-port resistance, which is governed at the transition by the resistance exponent straight phi(r). By employing renormalization group methods we calculate straight phi(r) for arbitrary r to one-loop order. Then we address the fractal dimensions characterizing directed percolation clusters. Via considering distinct values of the nonlinearity r, we determine the dimension of the red bonds, the chemical path, and the backbone to two-loop order.

  1. Nanoporous carbon tunable resistor/transistor and methods of production thereof

    Science.gov (United States)

    Biener, Juergen; Baumann, Theodore F; Dasgupta, Subho; Hahn, Horst

    2014-04-22

    In one embodiment, a tunable resistor/transistor includes a porous material that is electrically coupled between a source electrode and a drain electrode, wherein the porous material acts as an active channel, an electrolyte solution saturating the active channel, the electrolyte solution being adapted for altering an electrical resistance of the active channel based on an applied electrochemical potential, wherein the active channel comprises nanoporous carbon arranged in a three-dimensional structure. In another embodiment, a method for forming the tunable resistor/transistor includes forming a source electrode, forming a drain electrode, and forming a monolithic nanoporous carbon material that acts as an active channel and selectively couples the source electrode to the drain electrode electrically. In any embodiment, the electrolyte solution saturating the nanoporous carbon active channel is adapted for altering an electrical resistance of the nanoporous carbon active channel based on an applied electrochemical potential.

  2. Intermittency-induced criticality in a resistor-inductor-diode circuit.

    Science.gov (United States)

    Potirakis, Stelios M; Contoyiannis, Yiannis; Diakonos, Fotios K; Hanias, Michael P

    2017-04-01

    The current fluctuations of a driven resistor-inductor-diode circuit are investigated here looking for signatures of critical behavior monitored by the driving frequency. The experimentally obtained time series of the voltage drop across the resistor (as directly proportional to the current flowing through the circuit) were analyzed by means of the method of critical fluctuations in analogy to thermal critical systems. Intermittent criticality was revealed for a critical frequency band signifying the transition between the normal rectifier phase in the low frequencies and a full-wave conducting, capacitorlike phase in the high frequencies. The transition possesses critical characteristics with a characteristic exponent p_{l}=1.65. A fractal analysis in terms of the rescale range (R/RSS) and detrended fluctuation analysis methods yielded results fully compatible with the critical dynamics analysis. Suggestions for the interpretation of the observed behavior in terms of p-n junction operation are discussed.

  3. Programmable diode/resistor-like behavior of nanostructured vanadium pentoxide xerogel thin film.

    Science.gov (United States)

    Wan, Zhenni; Darling, Robert B; Anantram, M P

    2015-11-11

    Electrical properties of a Cr/V2O5/Cr structure are investigated and switching of the device due to electrochemical reactions is observed at low bias (resistor (reverse sweep first). The switching is irreversible and persistent, lasting for more than one month. By performing environmental tests, we prove that water molecules in the atmosphere and intercalated in the xerogel film are involved in the electrochemical reactions. It is proposed that an interfacial layer with reduced oxidation state forms at the Cr/V2O5 interface, and creates a higher Schottky barrier due to rise of electron affinity. Different interfacial layer thicknesses in forward and reverse first sweeps are responsible for different I-V characteristics in subsequent sweeps. The results suggest future applications of these V2O5 thin films in low-power read-only memory devices and diode-resistor networks.

  4. Leaf venation, as a resistor, to optimize a switchable IR absorber.

    Science.gov (United States)

    Alston, M E; Barber, R

    2016-08-24

    Leaf vascular patterns are the mechanisms and mechanical support for the transportation of fluidics for photosynthesis and leaf development properties. Vascular hierarchical networks in leaves have far-reaching functions in optimal transport efficiency of functional fluidics. Embedding leaf morphogenesis as a resistor network is significant in the optimization of a translucent thermally functional material. This will enable regulation through pressure equalization by diminishing flow pressure variation. This paper investigates nature's vasculature networks that exhibit hierarchical branching scaling applied to microfluidics. To enable optimum potential for pressure drop regulation by algorithm design. This code analysis of circuit conduit optimization for transport fluidic flow resistance is validated against CFD simulation, within a closed loop network. The paper will propose this self-optimization, characterization by resistance seeking targeting to determine a microfluidic network as a resistor. To advance a thermally function material as a switchable IR absorber.

  5. Depth of interaction detection with enhanced position-sensitive proportional resistor network

    International Nuclear Information System (INIS)

    Lerche, Ch.W.; Benlloch, J.M.; Sanchez, F.; Pavon, N.; Gimenez, N.; Fernandez, M.; Gimenez, M.; Sebastia, A.; Martinez, J.; Mora, F.J.

    2005-01-01

    A new method of determining the depth of interaction of γ-rays in thick inorganic scintillation crystals was tested experimentally. The method uses the strong correlation between the width of the scintillation light distribution within large continuous crystals and the γ-ray's interaction depth. This behavior was successfully reproduced by a theoretical model distribution based on the inverse square law. For the determination of the distribution's width, its standard deviation σ is computed using an enhanced position-sensitive proportional resistor network which is often used in γ-ray-imaging devices. Minor changes of this known resistor network allow the analog and real-time determination of the light distribution's 2nd moment without impairing the measurement of the energy and centroid. First experimental results are presented that confirm that the described method works correctly. Since only some cheap electronic components, but no additional detectors or crystals are required, the main advantage of this method is its low cost

  6. X-Ray Characterization of Resistor/Dielectric Material for Low Temperature Co-Fired Ceramic Packages

    International Nuclear Information System (INIS)

    DIMOS, DUANE B.; KOTULA, PAUL G.; RODRIGUEZ, MARK A.; YANG, PIN

    1999-01-01

    High temperature XRD has been employed to monitor the devitrification of Dupont 951 low temperature co-fired ceramic (LTCC) and Dupont E84005 resistor ink. The LTCC underwent devitrification to an anorthite phase in the range of 835-875 C with activation energy of 180 kJ/mol as calculated from kinetic data. The resistor paste underwent devitrification in the 835-875 C range forming monoclinic and hexagonal celcian phases plus a phase believed to be a zinc-silicate. RuO(sub 2) appeared to be stable within this devitrified resistor matrix. X-ray radiography of a co-fired circuit indicated good structural/chemical compatibility between the resistor and LTCC

  7. Development of resistor assemblies at 14 UD pelletron accelerator facility BARC-TIFR, Mumbai

    International Nuclear Information System (INIS)

    Ramlal; Ekambaram, M.; Matkar, U.V.; Lokare, R.N.; Gore, J.A.; Tambwekar, V.V.; Kulkarni, S.G.; Gupta, A.K.; Bhagwat, P.V.; Kailas, S.; Karande, J.N.; Kurup, M.B.

    2002-01-01

    An important consideration in high voltage design of an electrostatic accelerator is the potential grading system used to divide the terminal potential equitably (or as required) across the column or tube electrode gaps. This is generally accomplished by tapping the electrode potentials from across a resistor-chain or from a series of corona gaps as in the Pelletron Accelerator. However, each potential grading system has its own set of advantages and disadvantages

  8. Use of a Pre-Insertion Resistor to Minimize Zero-Missing Phenomenon and Switching Overvoltages

    DEFF Research Database (Denmark)

    Bak, Claus Leth; da Silva, Filipe Miguel Faria; Gudmundsdottir, Unnur Stella

    2009-01-01

    With the increasing use of High-Voltage Cables, which have different electric characteristics from Overhead Lines, phenomenon like current zero-missing start to appear more often on the transmission systems. Methods to prevent zero-missing phenomenon are still being studied and compared to see wh...... an optimal value of the resistance of the pre-insertion resistor that results in minimizing both the zero-missing phenomenon and switching overvoltages simultaneously....

  9. Designing a Signal Conditioning System with Software Calibration for Resistor-feedback Patch Clamp Amplifier.

    Science.gov (United States)

    Hu, Gang; Zhu, Quanhui; Qu, Anlian

    2005-01-01

    In this paper, a programmable signal conditioning system based on software calibration for resistor-feedback patch clamp amplifier (PCA) has been described, this system is mainly composed of frequency correction, programmable gain and filter whose parameters are configured by software automatically to minimize the errors, A lab-designed data acquisition system (DAQ) is used to implement data collections and communications with PC. The laboratory test results show good agreement with design specifications.

  10. Effects of varying laser trimming geometries on thin film\\ud resistors

    OpenAIRE

    Alafogianni, Maria; Birkett, Martin; Penlington, Roger

    2017-01-01

    Purpose - This paper studies the effects of varying laser trim patterns on several performance parameters of thin film resistors such as the temperature coefficient of resistance (TCR) and target resistance value.\\ud \\ud Design/methodology/approach - The benefits and limitations of basic trim patterns are taken into consideration and the plunge cut, double plunge cut and the curved L-cut were selected to be modelled and tested experimentally. A computer simulation of the laser trim patterns h...

  11. Single pole rapid reclosing: effective damping of ehv switching surges through discharge resistors

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, T

    1965-04-30

    The stability of interconnecting circuits is very important and loss of synchronism of a complete network due to a temporary single-phase fault is operationally and economically undesirable. The use of grounding resistors together with load-break isolators which can be electrically or mechanically coupled to the circuit-breakers yield interesting possibilities in extra-high-voltage networks. The three problems, i.e., discharging of charged lines, damping of switching surges, and single-pole rapid-reclosing, can be solved through the use of a number of similar resistors and load-break isolators connected in series according to the voltage. The thermal and electrical stresses of the resistors can be kept within permissible limits. The time required for arc extinction and the limits in respect of length of lines will have to be determined by actual tests. For single-pole rapid-reclosing during a single-phase earth fault the switching operations on both sides of the line must be simultaneous. Because of the very small divergence of the opening and making times of modern circuit-breakers it will be sufficient only to synchronise the operating impulse.

  12. History of resistor array infrared projectors: hindsight is always 100% operability

    Science.gov (United States)

    Williams, Owen M.; Goldsmith, George C., II; Stockbridge, Robert G.

    2005-05-01

    Numerous infrared scene projection technologies have been investigated since the 1970s. Notably, from the late 1980s the development of the first resistor array infrared projectors gained leverage from the strong concurrent developments within focal plane array imaging technology, linked by the common need for large integrated circuits comprising a 2-dimensional array of interconnected unit cells. In the resistor array case, it is the unit cell comprising the resistively heated emitter and its dedicated drive circuit that determines the projector response to its associated scene generator commands. In this paper we review the development of resistor array technology from a historical perspective, concentrating on the unit cell developments. We commence by describing the technological innovations that forged the way, sharing along the way stories of the successes and failures, all of which contributed to the steady if somewhat eventful growth of the critical knowledge base that underpins the strength of today's array technology. We conclude with comments on the characteristics and limitations of the technology and on the prospects for future array development.

  13. Pyramidal resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V; Vasquez, F Guevara

    2010-01-01

    We introduce an inversion algorithm for electrical impedance tomography (EIT) with partial boundary measurements in two dimensions. It gives stable and fast reconstructions using sparse parameterizations of the unknown conductivity on optimal grids that are computed as part of the inversion. We follow the approach in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD thesis Rice University, Houston, TX, USA) that connects inverse discrete problems for resistor networks to continuum EIT problems, using optimal grids. The algorithm in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) is based on circular resistor networks, and solves the EIT problem with full boundary measurements. It is extended in Borcea et al (2010 Inverse Problems 26 045010) to EIT with partial boundary measurements, using extremal quasi-conformal mappings that transform the problem to one with full boundary measurements. Here we introduce a different class of optimal grids, based on resistor networks with pyramidal topology, that is better suited for the partial measurements setup. We prove the unique solvability of the discrete inverse problem for these networks and develop an algorithm for finding them from the measurements of the Dirichlet to Neumann map. Then, we show how to use the networks to define the optimal grids and to approximate the unknown conductivity. We assess the performance of our approach with numerical simulations and compare the results with those in Borcea et al (2010)

  14. Biased resistor network model for electromigration failure and related phenomena in metallic lines

    Science.gov (United States)

    Pennetta, C.; Alfinito, E.; Reggiani, L.; Fantini, F.; Demunari, I.; Scorzoni, A.

    2004-11-01

    Electromigration phenomena in metallic lines are studied by using a biased resistor network model. The void formation induced by the electron wind is simulated by a stochastic process of resistor breaking, while the growth of mechanical stress inside the line is described by an antagonist process of recovery of the broken resistors. The model accounts for the existence of temperature gradients due to current crowding and Joule heating. Alloying effects are also accounted for. Monte Carlo simulations allow the study within a unified theoretical framework of a variety of relevant features related to the electromigration. The predictions of the model are in excellent agreement with the experiments and in particular with the degradation towards electrical breakdown of stressed Al-Cu thin metallic lines. Detailed investigations refer to the damage pattern, the distribution of the times to failure (TTFs), the generalized Black’s law, the time evolution of the resistance, including the early-stage change due to alloying effects and the electromigration saturation appearing at low current densities or for short line lengths. The dependence of the TTFs on the length and width of the metallic line is also well reproduced. Finally, the model successfully describes the resistance noise properties under steady state conditions.

  15. A study on embedded resistor components fabricated by laser micro-cladding and rapid prototype

    International Nuclear Information System (INIS)

    Li Huiling; Zeng Xiaoyan

    2006-01-01

    With the rapid development of IC and packaging, electronic devices are required to be smaller, to have a high-density integration, to become multifunction and to be of lower cost and high-reliability. Thick-film technology is not able to meet the current developing demands because of its shortcomings, such as the limit of pattern resolution, the severe torsion and delay of high-speed signal transmission. The speed and quality of signal transmission will be improved if embedded resistor components are directly integrated in the multiplayer substrate of multi-chip or laminated module, and high-density integration and reliability are achieved because the short interconnection and the less soldering point. In this paper, a technique named laser micro-cladding and rapid prototype is used to directly fabricate embedded resistor units on the multiplayer ceramic substrate without using a mask and high-temperature sintering, and without trimming resistor, which will simplify processing and decrease cost as well as improving high-speed and reliable performance

  16. Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

    Science.gov (United States)

    Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

    2016-07-22

    The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

  17. Method of triggering the vacuum arc in source with a resistor

    International Nuclear Information System (INIS)

    Zheng Le; Lan Zhaohui; Long Jidong; Peng Yufei; Li Jie; Yang Zhen; Dong Pan; Shi Jinshui

    2014-01-01

    Background: The metal vapor vacuum arc (MEVVA) ion source is a common source which provides strong metal ion flow. To trigger this ion source, a high-voltage trigger pulse generator and a high-voltage isolation pulse transformer are needed, which makes the power supply system complex. Purpose: To simplify the power supply system, a trigger method with a resistor was introduced, and some characteristics of this method were studied. Methods: The ion flow provided by different main arc current was measured, as well as the trigger current. The main arc current and the ion current were recorded with different trigger resistances. Results: Experimental results showed that, within a certain range of resistances, the larger the resistance value, the more difficult it was to success fully trigger the source. Meanwhile, the main arc rising edge became slower on the increasing in the trigger time. However, the resistance value increment had hardly impact on the intensity of ion flow extracted in the end, The ion flow became stronger with the increasing main arc current. Conclusion: The power supply system of ion source is simplified by using the trigger method with a resistor. Only a suitable resistor was needed to complete the conversion process from trigger to arc initiating. (authors)

  18. Maximum Bandwidth Enhancement of Current Mirror using Series-Resistor and Dynamic Body Bias Technique

    Directory of Open Access Journals (Sweden)

    V. Niranjan

    2014-09-01

    Full Text Available This paper introduces a new approach for enhancing the bandwidth of a low voltage CMOS current mirror. The proposed approach is based on utilizing body effect in a MOS transistor by connecting its gate and bulk terminals together for signal input. This results in boosting the effective transconductance of MOS transistor along with reduction of the threshold voltage. The proposed approach does not affect the DC gain of the current mirror. We demonstrate that the proposed approach features compatibility with widely used series-resistor technique for enhancing the current mirror bandwidth and both techniques have been employed simultaneously for maximum bandwidth enhancement. An important consequence of using both techniques simultaneously is the reduction of the series-resistor value for achieving the same bandwidth. This reduction in value is very attractive because a smaller resistor results in smaller chip area and less noise. PSpice simulation results using 180 nm CMOS technology from TSMC are included to prove the unique results. The proposed current mirror operates at 1Volt consuming only 102 µW and maximum bandwidth extension ratio of 1.85 has been obtained using the proposed approach. Simulation results are in good agreement with analytical predictions.

  19. A new computer-aided simulation model for polycrystalline silicon film resistors

    Science.gov (United States)

    Ching-Yuan Wu; Weng-Dah Ken

    1983-07-01

    A general transport theory for the I-V characteristics of a polycrystalline film resistor has been derived by including the effects of carrier degeneracy, majority-carrier thermionic-diffusion across the space charge regions produced by carrier trapping in the grain boundaries, and quantum mechanical tunneling through the grain boundaries. Based on the derived transport theory, a new conduction model for the electrical resistivity of polycrystalline film resitors has been developed by incorporating the effects of carrier trapping and dopant segregation in the grain boundaries. Moreover, an empirical formula for the coefficient of the dopant-segregation effects has been proposed, which enables us to predict the dependence of the electrical resistivity of phosphorus-and arsenic-doped polycrystalline silicon films on thermal annealing temperature. Phosphorus-doped polycrystalline silicon resistors have been fabricated by using ion-implantation with doses ranged from 1.6 × 10 11 to 5 × 10 15/cm 2. The dependence of the electrical resistivity on doping concentration and temperature have been measured and shown to be in good agreement with the results of computer simulations. In addition, computer simulations for boron-and arsenic-doped polycrystalline silicon resistors have also been performed and shown to be consistent with the experimental results published by previous authors.

  20. Age group classification and gender detection based on forced expiratory spirometry.

    Science.gov (United States)

    Cosgun, Sema; Ozbek, I Yucel

    2015-08-01

    This paper investigates the utility of forced expiratory spirometry (FES) test with efficient machine learning algorithms for the purpose of gender detection and age group classification. The proposed method has three main stages: feature extraction, training of the models and detection. In the first stage, some features are extracted from volume-time curve and expiratory flow-volume loop obtained from FES test. In the second stage, the probabilistic models for each gender and age group are constructed by training Gaussian mixture models (GMMs) and Support vector machine (SVM) algorithm. In the final stage, the gender (or age group) of test subject is estimated by using the trained GMM (or SVM) model. Experiments have been evaluated on a large database from 4571 subjects. The experimental results show that average correct classification rate performance of both GMM and SVM methods based on the FES test is more than 99.3 % and 96.8 % for gender and age group classification, respectively.

  1. Abdominal wall reconstruction for large incisional hernia restores expiratory lung function

    DEFF Research Database (Denmark)

    Jensen, Kristian K; Backer, Vibeke; Jorgensen, Lars N

    2017-01-01

    BACKGROUND: Respiratory complications secondary to intermittent intra-abdominal hypertension and/or atelectasis are common after abdominal wall reconstruction for large incisional hernias. It is unknown if the respiratory function of this patient group is affected long term or impairs activities...... of daily living. We hypothesized that abdominal wall reconstruction for large incisional hernia would not lead to improved, long-term pulmonary function or respiratory quality of life. METHODS: Eighteen patients undergoing open abdominal wall reconstruction with mesh for a large incisional hernia...... (horizontal fascial defect width >10 cm) were compared with 18 patients with an intact abdominal wall who underwent colorectal resection. Patients were examined pre- and 1-year postoperatively. Examined measures included forced vital capacity, forced expiratory volume in first second, peak expiratory flow...

  2. Segmentation of expiratory and inspiratory sounds in baby cry audio recordings using hidden Markov models.

    Science.gov (United States)

    Aucouturier, Jean-Julien; Nonaka, Yulri; Katahira, Kentaro; Okanoya, Kazuo

    2011-11-01

    The paper describes an application of machine learning techniques to identify expiratory and inspiration phases from the audio recording of human baby cries. Crying episodes were recorded from 14 infants, spanning four vocalization contexts in their first 12 months of age; recordings from three individuals were annotated manually to identify expiratory and inspiratory sounds and used as training examples to segment automatically the recordings of the other 11 individuals. The proposed algorithm uses a hidden Markov model architecture, in which state likelihoods are estimated either with Gaussian mixture models or by converting the classification decisions of a support vector machine. The algorithm yields up to 95% classification precision (86% average), and its ability generalizes over different babies, different ages, and vocalization contexts. The technique offers an opportunity to quantify expiration duration, count the crying rate, and other time-related characteristics of baby crying for screening, diagnosis, and research purposes over large populations of infants.

  3. Focal airtrapping at expiratory high-resolution CT: comparison with pulmonary function tests

    International Nuclear Information System (INIS)

    Kauczor, H.U.; Hast, J.; Heussel, C.P.; Mildenberger, P.; Thelen, M.; Schlegel, J.

    2000-01-01

    This study was undertaken to determine prevalence, extent, and severity of focal airtrapping at expiratory high-resolution CT, and to compare focal airtrapping with age, gender, pulmonary function tests, and blood gas analysis. Two-hundred seventeen patients with and without pulmonary disease underwent paired inspiratory/expiratory high-resolution CT. Six scan pairs with corresponding scan levels were visually assessed for focal - not diffuse - airtrapping using a four-point scale. Pulmonary function tests and blood gas analysis were available for correlation in all patients (mean interval 5 days). Focal airtrapping with lower lung predominance was observed in 80 % of patients. Twenty-six of 26 patients with restrictive lung function impairment exhibited focal airtrapping (mean score 2.4), whereas only 72 of 98 (74 %) patients with obstruction did (mean score 1.5; p < 0.05). Fifty-eight of 70 (83 %) patients with normal lung function (mean score 1.8) and 19 of 23 (83 %) patients with mixed impairment (mean score 1.8) had focal airtrapping. Focal airtrapping showed negative correlations with static lung volumes (-0.27 to -0.37; p < 0.001) in all patients and moderate positive correlations with dynamic parameters (0.3-0.4; p < 0.001) in patients with obstruction. No significant correlations were found with age, gender, and blood gas analysis. Visual assessment of focal - not diffuse - airtrapping at expiratory high-resolution CT does not correlate with physiological evidence of obstruction as derived from pulmonary function tests since the perception of focal airtrapping requires an adequate expiratory increase in lung density. (orig.)

  4. Dead space and slope indices from the expiratory carbon dioxide tension-volume curve

    OpenAIRE

    Kars, Alice; Bogaard, Jan; Stijnen, Theo; Vries, J.; Verbraak, Anton; Hilvering, C.

    1997-01-01

    textabstractThe slope of phase 3 and three noninvasively determined dead space estimates derived from the expiratory carbon dioxide tension (PCO2) versus volume curve, including the Bohr dead space (VD,Bohr), the Fowler dead space (VD,Fowler) and pre-interface expirate (PIE), were investigated in 28 healthy control subjects, 12 asthma and 29 emphysema patients (20 severely obstructed and nine moderately obstructed) with the aim to establish diagnostic value. Because breath volume and frequenc...

  5. Thoracoabdominal mobility evaluation by photogrammetry in newborns after expiratory flow increase technique

    Directory of Open Access Journals (Sweden)

    Júlia Isabel de Araújo Guerra

    Full Text Available Abstract Introduction: Expiratory flow increase is a maneuver of respiratory physical therapy that promotes flow direction to the upper airways however, when applied in newborns, it may result in changes of thoracoabdominal mobility. Objective: To evaluate the thoracoabdominal mobility by photogrammetry in newborns after expiratory flow increase technique. Methods: Experimental blind study performed with newborns in supine position on a support table with upper limbs flexed, abducted and externally rotated and hip flexed at 110°. Adhesive markers were allocated for geometric delimitation of the thoracoabdominal compartment and expiratory flow increase technique was performed for 5 minutes with the therapist’s hands on the thorax and abdomen. Newborns were filmed before and after the maneuver and the frames were analyzed in AutoCAD® software by a blinded investigator at the time of the procedure. The largest and the smallest thoracoabdominal area were expressed in cm2 and the mean values were compared between two moments (pre and post maneuver by paired t test. Results: Twenty newborns with a mean age of 39 weeks were included. Before the maneuver, thoracoabdominal area was 56.1 cm2 during expiration and 59.7 cm2 during inspiration, and after the maneuver the value was 56.2 cm2 during expiration and 59.8 cm2 during inspiration, with no statistical difference between before and after (p = 0.97, p = 0.92, respectively. Conclusion: Results demonstrate that expiratory flow increase technique does not seem to change thoracoabdominal mobility of healthy newborns.

  6. Impact of humidification and nebulization during expiratory limb protection: an experimental bench study.

    Science.gov (United States)

    Tonnelier, Alexandre; Lellouche, François; Bouchard, Pierre Alexandre; L'Her, Erwan

    2013-08-01

    Different filtering devices are used during mechanical ventilation to avoid dysfunction of flow and pressure transducers or for airborne microorganisms containment. Water condensates, resulting from the use of humidifiers, but also residual nebulization particles may have a major influence on expiratory limb resistance. To evaluate the influence of nebulization and active humidification on the resistance of expiratory filters. A respiratory system analog was constructed using a test lung, an ICU ventilator, heated humidifiers, and a piezoelectric nebulizer. Humidifiers were connected to different types of circuits (unheated, mono-heated, new-generation and old-generation bi-heated). Five filter types were evaluated: electrostatic, heat-and-moisture exchanger, standard, specific, and internal heated high-efficiency particulate air [HEPA] filter. Baseline characteristics were obtained from each dry filter. Differential pressure measurements were carried out after 24 hours of continuous in vitro use for each condition, and after 24 hours of use with an old-generation bi-heated circuit without nebulization. While using unheated circuits, measurements had to be interrupted before 24 hours for all the filtering devices except the internal heated HEPA filter. The heat-and-moisture exchangers occluded before 24 hours with the unheated and mono-heated circuits. The circuit type, nebulization practice, and duration of use did not influence the internal heated HEPA filter resistance. Expiratory limb filtration is likely to induce several major adverse events. Expiratory filter resistance increase is due mainly to the humidification circuit type, rather than to nebulization. If filtration is mandatory while using an unheated circuit, a dedicated filter should be used for ≤ 24 hours, or a heated HEPA for a longer duration.

  7. Application of dead space fraction to titrate optimal positive end-expiratory pressure in an ARDS swine model.

    Science.gov (United States)

    Bian, Weishuai; Chen, Wei; Chao, Yangong; Wang, Lan; Li, Liming; Guan, Jian; Zang, Xuefeng; Zhen, Jie; Sheng, Bo; Zhu, Xi

    2017-04-01

    This study aimed to apply the dead space fraction [ratio of dead space to tidal volume (VD/VT)] to titrate the optimal positive end-expiratory pressure (PEEP) in a swine model of acute respiratory distress syndrome (ARDS). Twelve swine models of ARDS were constructed. A lung recruitment maneuver was then conducted and the PEEP was set at 20 cm H 2 O. The PEEP was reduced by 2 cm H 2 O every 10 min until 0 cm H 2 O was reached, and VD/VT was measured after each decrement step. VD/VT was measured using single-breath analysis of CO 2 , and calculated from arterial CO 2 partial pressure (PaCO 2 ) and mixed expired CO 2 (PeCO 2 ) using the following formula: VD/VT = (PaCO 2 - PeCO 2 )/PaCO 2 . The optimal PEEP was identified by the lowest VD/VT method. Respiration and hemodynamic parameters were recorded during the periods of pre-injury and injury, and at 4 and 2 cm H 2 O below and above the optimal PEEP (Po). The optimal PEEP in this study was found to be 13.25±1.36 cm H 2 O. During the Po period, VD/VT decreased to a lower value (0.44±0.08) compared with that during the injury period (0.68±0.10) (P<0.05), while the intrapulmonary shunt fraction reached its lowest value. In addition, a significant change of dynamic tidal respiratory compliance and oxygenation index was induced by PEEP titration. These results indicate that minimal VD/VT can be used for PEEP titration in ARDS.

  8. Comparison of intermittent positive pressure breathing and temporary positive expiratory pressure in patients with severe chronic obstructive pulmonary disease.

    Science.gov (United States)

    Nicolini, Antonello; Mollar, Elena; Grecchi, Bruna; Landucci, Norma

    2014-01-01

    Results supporting the use and the effectiveness of positive expiratory, pressure devices in chronic obstructive pulmonary disease (COPD) patients are still controversial, We have tested the hypothesis that adding TPEP or IPPB to standard pharmacological therapy may provide additional clinical benefit over, pharmacological therapy only in patients with severe COPD. Fourty-five patients were randomized in three groups: a group was treated; with IPPB,a group was treated with TPEP and a group with pharmacological; therapy alone (control group). Primary outcome measures included the measurement of scale or, questionnaire concerning dyspnea (MRC scale),dyspnea,cough, and, sputum (BCSS) and quality of life (COPD assessment test) (CAT). Secondary, outcome measures were respiratory function testing,arterial blood gas,analysis,and hematological examinations. Both patients in the IPPB group and in the TPEP group showed a significant, improvement in two of three tests (MRC,CAT) compared to the control, group.However,in the group comparison analysis for, the same variables between IPPB group and TPEP group we observed a, significant improvement in the IPPB group (P≤.05 for MRC and P≤.01 for, CAT). The difference of action of the two techniques are evident in the results of, pulmonary function testing: IPPB increases FVC, FEV1, and MIP; this reflects, its capacity to increase lung volume. Also TPEP increases FVC and FEV1 (less, than IPPB), but increases MEP, while decreasing total lung capacity and, residual volume. The two techniques (IPPB and TPEP) improves significantly dyspnea; quality of; life tools and lung function in patients with severe COPD. IPPB demonstrated a greater effectiveness to improve dyspnea and quality of life tools (MRC, CAT) than TPEP. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

  9. Differing responses in right and left ventricular filling, loading and volumes during positive end-expiratory pressure

    International Nuclear Information System (INIS)

    Schulman, D.S.; Biondi, J.W.; Matthay, R.A.; Zaret, B.L.; Soufer, R.

    1989-01-01

    Using a combined hemodynamic and radionuclide technique, 20 patients with varied ventricular function were evaluated during positive end-expiratory pressure (PEEP) application. Left ventricular (LV) and right ventricular (RV) ejection fractions and cardiac output were measured, and ventricular volumes were derived. Seven patients (group 1) who had an increase in LV end-diastolic volume with PEEP and 13 patients (group 2) who had the more typical response, a decrease in LV end-diastolic volume with PEEP, were identified. Compared with group 2, group 1 patients had a higher incidence of coronary artery disease (5 of 7 vs 1 of 13, p less than 0.005) and lower cardiac output (3.9 +/- 1.6 vs 9.1 +/- 3.2 liters/min, p less than 0.005), LV ejection fraction (27 +/- 13 vs 51 +/- 21%, p less than 0.05), RV ejection fraction (15 +/- 6 vs 32 +/- 8%, p less than 0.005) and peak filling rate (1.32 +/- 0.43 vs 3.51 +/- 1.70 end-diastolic volumes/s, p less than 0.05). LV and RV volumes increased and peak filling rate decreased with PEEP in group 1, whereas in group 2 LV volume decreased and RV volume and peak filling rate remained unchanged. Using stepwise regression analysis, the change in LV volume with PEEP was related directly to baseline systemic vascular resistance and inversely to baseline blood pressure. Similarly, the change in peak filling rate with PEEP was inversely related to the change in RV end-diastolic volume. Thus, the hemodynamic response to PEEP is heterogeneous and may be related to LV ischemia

  10. Regional specific mean expiratory gas flow from Slmsub(Kr) equilibrium inhalation data

    International Nuclear Information System (INIS)

    Hamilton, D.; Causer, D.A.; McIntosh, J.A.; Godfrey, K.R.

    1985-01-01

    A new method of analysing the data available from routine sup(81m) Kr equilibrium inhalation investigations has been developed. The data for analysis are acquired from a gamma camera in the form of a sequential series of images from which multiple breath activity-time curves are generated for eight regions in the lung. The method is based on a description of the behaviour of the radioactive gas in the lung using a mathematical model. Values of specific mean expiratory gas flow, that is mean expiratory gas flow per unit lung volume, are calculated from the application of the model to the expiratory phase only only of a single breath activity-time curve which is generated from the multiple breath activity-time curve using post-acquisition gating. This method overcomes the problem of non-uniform inspiratory concentration of tracer gas experienced in previously reported techniques of analysing inhalation data obtained using poorly soluble radioactive gases. The model is shown, in simulation studies, to be an adequate description of the behaviour of radioactive gas in the lung and the analysis technique is shown, in clinical studies, to be both reproducible and sensitive to disease state. (orig.)

  11. High resolution CT in cystic fibrosis--the contribution of expiratory scans

    International Nuclear Information System (INIS)

    Dorloechter, Ludger; Nes, Harald; Fluge, Gjermund; Rosendahl, Karen

    2003-01-01

    Introduction: The use of high-resolution computed tomography (HRCT) is well accepted as an accurate method for evaluation of lung parenchyma in cystic fibrosis (CF). Several scoring methods exist and, in common, all are based on HRCT findings during inspiration alone. Objective: To examine whether expiratory HRCT scans could add information about the degree of mosaic perfusion in patients with CF. Methods and patients: Pulmonary HRCT was performed in 17 CF patients (median age of 12 years) with 1-mm thin sections and 10-mm intervals during inspiration, followed by 1-mm thin sections with 20-mm intervals during expiration. HRCT was scored by using a modified Bhalla method. Results: The mean HRCT score was 8.2. Out of 17 patients, 11 (65%) demonstrated a pathological mosaic perfusion in expiration, while only three patients showed mosaic perfusion in inspiration. The degree of expiratory mosaic perfusion was graded as severe in nine patients and moderate in two patients. There was a significant correlation between our modified HRCT score and lung function, as measured by forced expiratory volume in 1 s (FEV1% predicted, P<0.01). Conclusion: Mosaic perfusion in expiration was a common pathological HRCT finding in our study group. The clinical significance of this finding needs further evaluation

  12. Inspiratory and expiratory computed tomographic volumetry for lung volume reduction surgery.

    Science.gov (United States)

    Morimura, Yuki; Chen, Fengshi; Sonobe, Makoto; Date, Hiroshi

    2013-06-01

    Three-dimensional (3D) computed tomographic (CT) volumetry has been introduced into the field of thoracic surgery, and a combination of inspiratory and expiratory 3D-CT volumetry provides useful data on regional pulmonary function as well as the volume of individual lung lobes. We report herein a case of a 62-year-old man with severe emphysema who had undergone lung volume reduction surgery (LVRS) to assess this technique as a tool for the evaluation of regional lung function and volume before and after LVRS. His postoperative pulmonary function was maintained in good condition despite a gradual slight decrease 2 years after LVRS. This trend was also confirmed by a combination of inspiratory and expiratory 3D-CT volumetry. We confirm that a combination of inspiratory and expiratory 3D-CT volumetry might be effective for the preoperative assessment of LVRS in order to determine the amount of lung tissue to be resected as well as for postoperative evaluation. This novel technique could, therefore, be used more widely to assess local lung function.

  13. High-precision ID-TIMS zircon U-Pb geochronology using new 1013 Ohm resistors

    Science.gov (United States)

    Von Quadt, A.; Buret, Y.; Large, S.; Peytcheva, I.; Trinquier, A.; Wotzlaw, J. F.

    2015-12-01

    Faraday cups equipped with high gain amplifiers provide a means to measure small ion beams in static mode without the limited linear range of ion counting systems. We tested the application of newly available 1013 Ohm resistors to ID-TIMS zircon U-Pb geochronology using a range of natural and synthetic reference materials. The TritonPlus-RPQ at the Institute of Geochemistry and Petrology, ETH Zurich, is equipped with five new 1013 Ohm resistors and one MasCom secondary electron multiplier, allowing to measure the 202-204-205-206-207-208Pb masses in static mode. U is measured subsequently as U-oxide (265-267-270UO2) during a second step, also in static Faraday mode. The gain calibration of the 1013 Ohm resistors was performed using the procedure of Trinquier (2014), with 144Nd-146Nd being measured using 1011 Ohm resistor and 142-143-145-148-150Nd being measured using 1013 Ohm resitors (Trinquier, 2014; Koornneef et al., 2014). Standard deviations of the noise in all five new 1013 Ohm resistors are lower than 5.0 x 10-6 over a 6 month period, with no shift occurring over this time interval. This new detector set-up was tested by analyzing natural zircon standard materials and synthetic U/Pb solutions (www.earthime.org), ranging in age from ~2 Ma to ~600 Ma. All natural zircon standards were chemically abraded (Mattinson, 2005) and all samples were spiked with the ET2535 tracer solution. U-Pb dates obtained using the static measurement routine are compared to measurements employing dynamic peak jumping routines on the MasCom multiplier. This study illustrates the benefits and current limitations of using high gain amplifiers to measure small ion beams for zircon U-Pb geochronology compared to conventional dynamic ion counting techniques. Mattinson, J.M. (2005) Chemical Geology 220:47-66; Trinquier, A. (2014) Application Note 30281; Koornneef, J. et al (2014) Analytica Chimica Acta 819:49-55.

  14. Experimental Study of Dispersion and Deposition of Expiratory Aerosols in Aircraft Cabins and Impact on Infectious Disease Transmission

    DEFF Research Database (Denmark)

    To, G.N.S.; Wan, M.P.; Chao, C.Y.H.

    2009-01-01

    The dispersion and deposition characteristics of polydispersed expiratory aerosols were investigated in an aircraft cabin mockup to study the transmission of infectious diseases. The airflow was characterized by particle image velocimetry (PIV) measurements. Aerosol dispersionwas measured...

  15. Design, development and evaluation of a resistor-based multiplexing circuit for a 20×20 SiPM array

    International Nuclear Information System (INIS)

    Wang, Zhonghai; Sun, Xishan; Lou, Kai; Meier, Joseph; Zhou, Rong; Yang, Chaowen; Zhu, Xiaorong; Shao, Yiping

    2016-01-01

    One technical challenge in developing a large-size scintillator detector with multiple Silicon Photomultiplier (SiPM) arrays is to read out a large number of detector output channels. To achieve this, different signal multiplexing circuits have been studied and applied with different performances and cost-effective tradeoffs. Resistor-based multiplexing circuits exhibit simplicity and signal integrity, but also present the disadvantage of timing shift among different channels. In this study, a resistor-based multiplexing circuit for a large-sized SiPM array readout was developed and evaluated by simulation and experimental studies. Similarly to a multiplexing circuit used for multi-anode PMT, grounding and branching resistors were connected to each SiPM output channel. The grounding resistor was used to simultaneously reduce the signal crosstalk among different channels and to improve timing performance. Both grounding and branching resistor values were optimized to maintain a balanced performance of the event energy, timing, and positioning. A multiplexing circuit was implemented on a compact PCB and applied for a flat-panel detector which consisted of a 32×32 LYSO scintillator crystals optically coupled to 5×5 SiPM arrays for a total 20×20 output channels. Test results showed excellent crystal identification for all 1024 LYSO crystals (each with 2×2×30 mm"3 size) with "2"2Na flood-source irradiation. The measured peak-to-valley ratio from typical crystal map profile is around 3:1 to 6.6:1, an average single crystal energy resolution of about 17.3%, and an average single crystal timing resolution of about 2 ns. Timing shift among different crystals, as reported in some other resistor-based multiplexing circuit designs, was not observed. In summary, we have designed and implemented a practical resistor-based multiplexing circuit that can be readily applied for reading out a large SiPM array with good detector performance.

  16. Design, development and evaluation of a resistor-based multiplexing circuit for a 20×20 SiPM array

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhonghai [College of Physical Science and Technology, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu (China); Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Tx (United States); Sun, Xishan [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Tx (United States); Lou, Kai [Department of Electrical and Computer Engineering, Rice University, Houston, Tx (United States); Meier, Joseph [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Tx (United States); Zhou, Rong; Yang, Chaowen [College of Physical Science and Technology, Key Laboratory of Radiation Physics and Technology, Ministry of Education, Sichuan University, Chengdu (China); Zhu, Xiaorong [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Tx (United States); Shao, Yiping [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Tx (United States)

    2016-04-21

    One technical challenge in developing a large-size scintillator detector with multiple Silicon Photomultiplier (SiPM) arrays is to read out a large number of detector output channels. To achieve this, different signal multiplexing circuits have been studied and applied with different performances and cost-effective tradeoffs. Resistor-based multiplexing circuits exhibit simplicity and signal integrity, but also present the disadvantage of timing shift among different channels. In this study, a resistor-based multiplexing circuit for a large-sized SiPM array readout was developed and evaluated by simulation and experimental studies. Similarly to a multiplexing circuit used for multi-anode PMT, grounding and branching resistors were connected to each SiPM output channel. The grounding resistor was used to simultaneously reduce the signal crosstalk among different channels and to improve timing performance. Both grounding and branching resistor values were optimized to maintain a balanced performance of the event energy, timing, and positioning. A multiplexing circuit was implemented on a compact PCB and applied for a flat-panel detector which consisted of a 32×32 LYSO scintillator crystals optically coupled to 5×5 SiPM arrays for a total 20×20 output channels. Test results showed excellent crystal identification for all 1024 LYSO crystals (each with 2×2×30 mm{sup 3} size) with {sup 22}Na flood-source irradiation. The measured peak-to-valley ratio from typical crystal map profile is around 3:1 to 6.6:1, an average single crystal energy resolution of about 17.3%, and an average single crystal timing resolution of about 2 ns. Timing shift among different crystals, as reported in some other resistor-based multiplexing circuit designs, was not observed. In summary, we have designed and implemented a practical resistor-based multiplexing circuit that can be readily applied for reading out a large SiPM array with good detector performance.

  17. Intrinsic positive end-expiratory pressure during one-lung ventilation of patients with pulmonary hyperinflation. Influence of low respiratory rate with unchanged minute volume.

    Science.gov (United States)

    Szegedi, L L; Barvais, L; Sokolow, Y; Yernault, J C; d'Hollander, A A

    2002-01-01

    We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.

  18. High altitude pulmonary edema and exercise at 4,400 meters on Mount McKinley. Effect of expiratory positive airway pressure.

    Science.gov (United States)

    Schoene, R B; Roach, R C; Hackett, P H; Harrison, G; Mills, W J

    1985-03-01

    Breathing against positive expiratory pressure has been used to improve gas exchange in many forms of pulmonary edema, and forced expiration against resistance during exercise has been advocated for climbing at high altitude as a method to optimize performance. To evaluate the effect of expiratory positive airway pressure (EPAP) on climbers with high altitude pulmonary edema (HAPE) and on exercise at high altitude, we studied four climbers with HAPE at rest and 13 healthy climbers during exercise on a bicycle ergometer at 4400 m. We measured minute ventilation (VI, L/min), arterial oxygen saturation (SaO2 percent), end-tidal carbon dioxide (PACO2, mm Hg), respiratory rate (RR), and heart rate (HR) during the last minute of a five minute interval at rest in the climbers with HAPE, and at rest, 300, and 600 kpm/minute workloads on a bicycle ergometer in the healthy subjects. The HAPE subjects demonstrated an increased SaO2 percent, no change in HR or VI, and a decrease in RR on EPAP as compared to control. In normal subjects, SaO2 percent, VI, and heart rate were significantly higher on EPAP 10 cm H2O than 0 cm H2O control (p less than 0.01, 0.01, and 0.05, respectively). The RR and PaCO2 were not significantly different. In summary, EPAP improves gas exchange in HAPE subjects at rest. The EPAP in normal subjects at high altitude resulted in a higher SaO2 percent at the expense of a higher VI and higher HR. These results suggest that the work of breathing is higher and the stroke volume lower on EPAP. The positive pressure mask may be an effective temporizing measure for victims of HAPE who cannot immediately go to a lower altitude.

  19. Diagnosis of bronchiectasis and airway wall thickening in children with cystic fibrosis: Objective airway-artery quantification

    NARCIS (Netherlands)

    W. Kuo-Kim (WieYing); M. de Bruijne (Marleen); J. Petersen (Jens); K. Nasserinejad (Kazem); Ozturk, H. (Hadiye); Chen, Y. (Yong); A. Perez-Rovira (Adria); H.A.W.M. Tiddens (Harm)

    2017-01-01

    textabstractObjectives: To quantify airway and artery (AA)-dimensions in cystic fibrosis (CF) and control patients for objective CT diagnosis of bronchiectasis and airway wall thickness (AWT). Methods: Spirometer-guided inspiratory and expiratory CTs of 11 CF and 12 control patients were collected

  20. Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN Key Exchange

    Directory of Open Access Journals (Sweden)

    Kish Laszlo B.

    2016-03-01

    Full Text Available We introduce two new Kirchhoff-law-Johnson-noise (KLJN secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR- KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT- KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.

  1. Thermometry using 1/8 W carbon resistors in a temperature region around 10 mK

    International Nuclear Information System (INIS)

    Kobayasi, S.; Shinohara, M.; Ono, K.

    1976-01-01

    The resistance-temperature characteristics of 1/8 W carbon resistors of grade ERC-18SG, manufactured by Matsushita, with the nominal values of 48, 82, 100, 220 and 330 Ω have been measured in the region 4.2 K to 25 mK and their application as thermometers in this region is confirmed. For the 82 Ω resistor, measurements were taken at temperatures below 10mK. The temperature dependence of the resistance was found to be linear on the log-log plot over a wide range below 50 mK. The sensitivity remains finite even at 6 mK, but below 10 mK rapid measurements were prevented by a considerable increase in the thermal relaxation time. Measurement of the characteristics of several 100 Ω resistors from two different sets showed that resistors from the same set separate into two groups with different characteristics. This become appreciable at temperatures below 4.2 K, so it is difficult to predict the behaviour of Matsushite resistors below 4.2 K from the characteristics at higher temperatures. (author)

  2. Diffraction phase microscopy imaging and multi-physics modeling of the nanoscale thermal expansion of a suspended resistor.

    Science.gov (United States)

    Wang, Xiaozhen; Lu, Tianjian; Yu, Xin; Jin, Jian-Ming; Goddard, Lynford L

    2017-07-04

    We studied the nanoscale thermal expansion of a suspended resistor both theoretically and experimentally and obtained consistent results. In the theoretical analysis, we used a three-dimensional coupled electrical-thermal-mechanical simulation and obtained the temperature and displacement field of the suspended resistor under a direct current (DC) input voltage. In the experiment, we recorded a sequence of images of the axial thermal expansion of the central bridge region of the suspended resistor at a rate of 1.8 frames/s by using epi-illumination diffraction phase microscopy (epi-DPM). This method accurately measured nanometer level relative height changes of the resistor in a temporally and spatially resolved manner. Upon application of a 2 V step in voltage, the resistor exhibited a steady-state increase in resistance of 1.14 Ω and in relative height of 3.5 nm, which agreed reasonably well with the predicted values of 1.08 Ω and 4.4 nm, respectively.

  3. Alpha- and gamma-detection by the avalanche detectors with metal-resistor-semiconductor structure

    International Nuclear Information System (INIS)

    Vetokhin, S.S.; Evtushenko, V.P.; Zalesskij, V.B.; Malyshev, S.A.; Chudakov, V.A.; Shunevich, S.A.

    1992-01-01

    Possibility to use silicon avalanche photodetectors with metal-resistor-semiconductor structure with 0.12 cm 2 photosensitive area as detectors of α-particles, as well as, photodetector of γ-quanta scintillation detector is shown. When detection of α-particles the energy resolution reaches 10%. R energy resolution for avalanche photodetector-CsI(Tl) scintillator system cooled up to - 60 deg C at 59 keV ( 241 Am) and 662 keV ( 137 Cs) energy of γ-quanta constitutes 60% and 80%, respectively. R minimal value in the conducted experiments is determined by the degree of irregularity of avalanche amplification along the photodetector area

  4. Silicon avalanche photodiodes on the base of metal-resistor-semiconductor (MRS) structures

    CERN Document Server

    Saveliev, V

    2000-01-01

    The development of a high quantum efficiency, fast photodetector, with internal gain amplification for the wavelength range 450-600 nm is one of the critical issues for experimental physics - registration of low-intensity light photons flux. The new structure of Silicon Avalanche Detectors with high internal amplification (10 sup 5 -10 sup 6) has been designed, manufactured and tested for registration of visible light photons and charge particles. The main features of Metal-Resistor-Semiconductor (MRS) structures are the high charge multiplication in nonuniform electric field near the 'needle' pn-junction and negative feedback for stabilization of avalanche process due to resistive layer.

  5. Logic delays of 5-μm resistor coupled Josephson logic

    International Nuclear Information System (INIS)

    Sone, J.; Yoshida, T.; Tahara, S.; Abe, H.

    1982-01-01

    Logic delays of resistor coupled Josephson logic (RCJL) have been investigated. An experimental circuit with a cascade chain of ten RCJL OR gates was fabricated using Pb-alloy Josephson IC technology with 5-μm minimum linewidth. Logic delay was measured to be as low as 10.8 ps with power dissipation of 11.7 μW. This demonstrates a switching operation faster than those reported for other Josephson gate designs. Comparison with computer-simulation results is also presented

  6. Quantum resistor-capacitor circuit with Majorana fermion modes in a chiral topological superconductor.

    Science.gov (United States)

    Lee, Minchul; Choi, Mahn-Soo

    2014-08-15

    We investigate the mesoscopic resistor-capacitor circuit consisting of a quantum dot coupled to spatially separated Majorana fermion modes in a chiral topological superconductor. We find substantially enhanced relaxation resistance due to the nature of Majorana fermions, which are their own antiparticles and are composed of particle and hole excitations in the same abundance. Further, if only a single Majorana mode is involved, the zero-frequency relaxation resistance is completely suppressed due to a destructive interference. As a result, the Majorana mode opens an exotic dissipative channel on a superconductor which is typically regarded as dissipationless due to its finite superconducting gap.

  7. A novel water resistor divider with a coaxial low-voltage arm.

    Science.gov (United States)

    Jia, Wei; Chen, Weiqing; Mao, Congguang; Zeng, Jiangtao

    2010-03-01

    A new style high voltage resistor divider made of saline solution has been constructed and tested. A coaxial construction is used on the low-voltage arm, as the signal extraction electrode, which can increase the attenuation ratio of the divider. The time response of divider limited by the stray parameter also can be improved. Comparing the results of calibrated experiment with the commonly used equal size copper sulfate dividers, the new probe has nearly five times increase in the attenuation ratio. The time response of the new style divider in the dimension of 30 mm in diameter and 400 mm in length can reach to 1 ns.

  8. Current redistribution in resistor networks: Fat-tail statistics in regular and small-world networks.

    Science.gov (United States)

    Lehmann, Jörg; Bernasconi, Jakob

    2017-03-01

    The redistribution of electrical currents in resistor networks after single-bond failures is analyzed in terms of current-redistribution factors that are shown to depend only on the topology of the network and on the values of the bond resistances. We investigate the properties of these current-redistribution factors for regular network topologies (e.g., d-dimensional hypercubic lattices) as well as for small-world networks. In particular, we find that the statistics of the current redistribution factors exhibits a fat-tail behavior, which reflects the long-range nature of the current redistribution as determined by Kirchhoff's circuit laws.

  9. High linearity current communicating passive mixer employing a simple resistor bias

    International Nuclear Information System (INIS)

    Liu Rongjiang; Guo Guiliang; Yan Yuepeng

    2013-01-01

    A high linearity current communicating passive mixer including the mixing cell and transimpedance amplifier (TIA) is introduced. It employs the resistor in the TIA to reduce the source voltage and the gate voltage of the mixing cell. The optimum linearity and the maximum symmetric switching operation are obtained at the same time. The mixer is implemented in a 0.25 μm CMOS process. The test shows that it achieves an input third-order intercept point of 13.32 dBm, conversion gain of 5.52 dB, and a single sideband noise figure of 20 dB. (semiconductor integrated circuits)

  10. Dispersive dielectric and conductive effects in 2D resistor-capacitor networks.

    Science.gov (United States)

    Hamou, R F; Macdonald, J R; Tuncer, E

    2009-01-14

    How to predict and better understand the effective properties of disordered material mixtures has been a long-standing problem in different research fields, especially in condensed matter physics. In order to address this subject and achieve a better understanding of the frequency-dependent properties of these systems, a large 2D L × L square structure of resistors and capacitors was used to calculate the immittance response of a network formed by random filling of binary conductor/insulator phases with 1000 Ω resistors and 10 nF capacitors. The effects of percolating clusters on the immittance response were studied statistically through the generation of 10 000 different random network samples at the percolation threshold. The scattering of the imaginary part of the immittance near the dc limit shows a clear separation between the responses of percolating and non-percolating samples, with the gap between their distributions dependent on both network size and applied frequency. These results could be used to monitor connectivity in composite materials. The effects of the content and structure of the percolating path on the nature of the observed dispersion were investigated, with special attention paid to the geometrical fractal concept of the backbone and its influence on the behavior of relaxation-time distributions. For three different resistor-capacitor proportions, the appropriateness of many fitting models was investigated for modeling and analyzing individual resistor-capacitor network dispersed frequency responses using complex-nonlinear-least-squares fitting. Several remarkable new features were identified, including a useful duality relationship and the need for composite fitting models rather than either a simple power law or a single Davidson-Cole one. Good fits of data for fully percolating random networks required two dispersive fitting models in parallel or series, with a cutoff at short times of the distribution of relaxation times of one of

  11. Experimental Modeling of Monolithic Resistors for Silicon ICS with a Robust Optimizer-Driving Scheme

    Directory of Open Access Journals (Sweden)

    Philippe Leduc

    2002-06-01

    Full Text Available Today, an exhaustive library of models describing the electrical behavior of integrated passive components in the radio-frequency range is essential for the simulation and optimization of complex circuits. In this work, a preliminary study has been done on Tantalum Nitride (TaN resistors integrated on silicon, and this leads to a single p-type lumped-element circuit. An efficient extraction technique will be presented to provide a computer-driven optimizer with relevant initial model parameter values (the "guess-timate". The results show the unicity in most cases of the lumped element determination, which leads to a precise simulation of self-resonant frequencies.

  12. Deep breathing exercises with positive expiratory pressure in patients with multiple sclerosis - a randomized controlled trial.

    Science.gov (United States)

    Westerdahl, Elisabeth; Wittrin, Anna; Kånåhols, Margareta; Gunnarsson, Martin; Nilsagård, Ylva

    2016-11-01

    Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials. To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes. Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH 2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period. Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups. Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained. © 2015 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.

  13. Hand grip strength and maximum peak expiratory flow: determinants of bone mineral density of adolescent students.

    Science.gov (United States)

    Cossio-Bolaños, Marco; Lee-Andruske, Cynthia; de Arruda, Miguel; Luarte-Rocha, Cristian; Almonacid-Fierro, Alejandro; Gómez-Campos, Rossana

    2018-03-02

    Maintaining and building healthy bones during the lifetime requires a complicated interaction between a number of physiological and lifestyle factors. Our goal of this study was to analyze the association between hand grip strength and the maximum peak expiratory flow with bone mineral density and content in adolescent students. The research team studied 1427 adolescent students of both sexes (750 males and 677 females) between the ages of 11.0 and 18.9 years in the Maule Region of Talca (Chile). Weight, standing height, sitting height, hand grip strength (HGS), and maximum peak expiratory flow (PEF) were measured. Furthermore, bone mineral density (BMD) and total body bone mineral content (BMC) were determined by using the Dual-Energy X-Ray Absorptiometry (DXA). Hand grip strength and PEF were categorized in tertiles (lowest, middle, and highest). Linear regression was performed in steps to analyze the relationship between the variables. Differences between categories were determined through ANOVA. In males, the hand grip strength explained 18-19% of the BMD and 20-23% of the BMC. For the females, the percentage of variation occurred between 12 and 13% of the BMD and 17-18% of the BMC. The variation of PEF for the males was observed as 33% of the BMD and 36% of the BMC. For the females, both the BMD and BMC showed a variation of 19%. The HGS and PEF were divided into three categories (lowest, middle, and highest). In both cases, significant differences occurred in bone density health between the three categories. In conclusion, the HGS and the PEF related positively to the bone density health of both sexes of adolescent students. The adolescents with poor values for hand grip strength and expiratory flow showed reduced values of BMD and BMC for the total body. Furthermore, the PEF had a greater influence on bone density health with respect to the HGS of the adolescents of both sexes.

  14. Effect of pilates method on inspiratory and expiratory muscle strength in the elderly

    Directory of Open Access Journals (Sweden)

    Beatriz Mendes Tozim

    2018-03-01

    Full Text Available With aging, the respiratory muscle strength decreases and the pilates method is a technique that uses respiration as one of its principles. The present study has the aim of analyzing the influence of the pilates method on respiratory muscle strength in older women. For the evaluation of respiratory muscle strength (inspiratory and expiratory, manovacuometer was used. Thirty-one older women were divided into two groups: 14 participated in the pilates group and 17 in the control group. Participants of the pilates group performed 16 sessions of pilates method with an hour of training, twice week for eight weeks. The control group participated in four educational lectures for eight weeks. For statistical analysis, Shapiro-Wilk, ANOVA for repeated measures (p <0.05 and Cohen’s D index were performed. The results showed significant difference and the mean effect for the Cohen’s D index expiratory muscle strength of the pilates group when comparing before (69.71 ± 25.48 and after (85.23 ± 22.21 training (p<0.05 with an increase of 23%. The results of inspiratory muscle strength were not significant but presented an average effect for the Cohen’s D index for the pilates group before (69.71 ± 35.46 and after (88.00 ± 34.87 training, with an increase of 27%. The control group did not present significant differences for the variables evaluated. It could be concluded that the pilates method is effective in improving expiratory muscle strength and provides positive effects on the increase in inspiratory muscle strength.

  15. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.

    Directory of Open Access Journals (Sweden)

    Samantha Torres Grams

    Full Text Available Maximal Inspiratory Pressure (MIP is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway.This study aimed to compare the MIP values assessed by standard method (MIPsta and by unidirectional expiratory valve method (MIPuni in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated.This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B at two moments (Tests 1 and 2 to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1] was used to determine intraobserver and interobserver reproducibility.The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O than the mean values for MIPsta (-102.5 ± 23.9 cmH2O (p<0.001. Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91, and high correlation for Test 2 (ICC[2,1] = 0.88. The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86 and evaluator B (ICC[2,1] = 0.77.MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.

  16. Modeling the Fate of Expiratory Aerosols and the Associated Infection Risk in an Aircraft Cabin Environment

    DEFF Research Database (Denmark)

    Wan, M.P.; To, G.N.S.; Chao, C.Y.H.

    2009-01-01

    to estimate the risk of infection by contact. The environmental control system (ECS) in a cabin creates air circulation mainly in the lateral direction, making lateral dispersions of aerosols much faster than longitudinal dispersions. Aerosols with initial sizes under 28 m in diameter can stay airborne......The transport and deposition of polydispersed expiratory aerosols in an aircraft cabin were simulated using a Lagrangian-based model validated by experiments conducted in an aircraft cabin mockup. Infection risk by inhalation was estimated using the aerosol dispersion data and a model was developed...

  17. A real time status monitor for transistor bank driver power limit resistor in boost injection kicker power supply

    Energy Technology Data Exchange (ETDEWEB)

    Mi, J.; Tan, Y.; Zhang, W.

    2011-03-28

    For years suffering of Booster Injection Kicker transistor bank driver regulator troubleshooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can monitor the driver regulator power limit resistor status in real time and warn machine operator if the power limit resistor changes values. This paper will mainly introduce the power supply and the new designed monitoring system. This real time resistor monitor circuit shows a useful method to monitor some critical parts in the booster pulse power supply. After two years accelerator operation, it shows that this monitor works well. Previously, we spent a lot of time in booster machine trouble shooting. We will reinstall all 4 PCB into Euro Card Standard Chassis when the power supply system will be updated.

  18. Thermal analysis and temperature characteristics of a braking resistor for high-speed trains for changes in the braking current

    Science.gov (United States)

    Lee, Dae-Dong; Kang, Hyun-Il; Shim, Jae-Myung

    2015-09-01

    Electric brake systems are used in high-speed trains to brake trains by converting the kinetic energy of a railway vehicle to electric energy. The electric brake system consists of a regenerative braking system and a dynamic braking system. When the electric energy generated during the dynamic braking process is changed to heat through the braking resistor, the braking resistor can overheat; thus, failures can occur to the motor block. In this paper, a braking resistor for a high-speed train was used to perform thermal analyses and tests, and the results were analyzed. The analyzed data were used to estimate the dependence of the brake currents and the temperature rises on speed changes up to 300 km/h, at which a test could not be performed.

  19. Compact chromium oxide thin film resistors for use in nanoscale quantum circuits

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A. [London Centre for Nanotechnology, UCL, 17–19 Gordon Street, London WC1H 0AH (United Kingdom)

    2014-12-14

    We report on the electrical characterisation of a series of thin amorphous chromium oxide (CrO{sub x}) films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the CrO{sub x} films was varied from 28 Ω/◻ to 32.6 kΩ/◻. The variation in resistance with cooling to 4.2 K in liquid helium was investigated; the sheet resistance at 4.2 K varied with composition from 65 Ω/◻ to above 20 GΩ/◻. All of the films measured displayed linear current–voltage characteristics at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium–silicon nanowires, interfaces between niobium–silicon and chromium oxide are required. We also characterised the contact resistance for one CrO{sub x} composition at an interface with niobium–silicon. We found that a gold intermediate layer is favourable: the specific contact resistivity of chromium-oxide-to-gold interfaces was 0.14 mΩcm{sup 2}, much lower than the value for direct CrO{sub x} to niobium–silicon contact. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.

  20. Low noise charge sensitive preamplifier DC stabilized without a physical resistor

    Science.gov (United States)

    Bertuccio, Giuseppe; Rehak, Pavel; Xi, Deming

    1994-09-13

    The invention is a novel charge sensitive preamplifier (CSP) which has no resistor in parallel with the feedback capacitor. No resetting circuit is required to discharge the feedback capacitor. The DC stabilization of the preamplifier is obtained by means of a second feedback loop between the preamplifier output and the common base transistor of the input cascode. The input transistor of the preamplifier is a Junction Field Transistor (JFET) with the gate-source junction forward biased. The detector leakage current flows into this junction. This invention is concerned with a new circuit configuration for a charge sensitive preamplifier and a novel use of the input Field Effect Transistor of the CSP itself. In particular this invention, in addition to eliminating the feedback resistor, eliminates the need for external devices between the detector and the preamplifier, and it eliminates the need for external circuitry to sense the output voltage and reset the CSP. Furthermore, the noise level of the novel CSP is very low, comparable with the performance achieved with other solutions. Experimental tests prove that this configuration for the charge sensitive preamplifier permits an excellent noise performance at temperatures including room temperature. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using a commercial JFET as input device of the preamplifier.

  1. Experimental verification of temperature coefficients of resistance for uniformly doped P-type resistors in SOI

    Science.gov (United States)

    Olszacki, M.; Maj, C.; Bahri, M. Al; Marrot, J.-C.; Boukabache, A.; Pons, P.; Napieralski, A.

    2010-06-01

    Many today's microsystems like strain-gauge-based piezoresistive pressure sensors contain doped resistors. If one wants to predict correctly the temperature impact on the performance of such devices, the accurate data about the temperature coefficients of resistance (TCR) are essential. Although such data may be calculated using one of the existing mobility models, our experiments showed that we can observe the huge mismatch between the calculated and measured values. Thus, in order to investigate the TCR values, a set of the test structures that contained doped P-type resistors was fabricated. As the TCR value also depends on the doping profile shape, we decided to use the very thin, 340 nm thick SOI wafers in order to fabricate the quasi-uniformly doped silicon layers ranging from 2 × 1017 at cm-3 to 1.6 × 1019 at cm-3. The results showed that the experimental data for the first-order TCR are quite far from the calculated ones especially over the doping range of 1018-1019 at cm-3 and quite close to the experimental ones obtained by Bullis about 50 years ago for bulk silicon. Moreover, for the first time, second-order coefficients that were not very consistent with the calculations were obtained.

  2. Interface analysis of embedded chip resistor device package and its effect on drop shock reliability.

    Science.gov (United States)

    Park, Se-Hoon; Kim, Sun Kyoung; Kim, Young-Ho

    2012-04-01

    In this study, the drop reliability of an embedded passive package is investigated under JESD22-B111 condition. Chip resistors were buried in a PCB board, and it was electrically interconnected by electroless and electrolytic copper plating on a tin pad of a chip resistor without intermetallic phase. However tin, nickel, and copper formed a complex intermetallic phase, such as (Cu, Ni)6Sn5, (Cu, Ni)3Sn, and (Ni, Cu)3Sn2, at the via interface and via wall after reflow and aging. Since the amount of the tin layer was small compared with the solder joint, excessive intermetallic layer growth was not observed during thermal aging. Drop failures are always initiated at the IMC interface, and as aging time increases Cu-Sn-Ni IMC phases are transformed continuously due to Cu diffusion. We studied the intermetallic formation of the Cu via interface and simulated the stress distribution of drop shock by using material properties and board structure of embedded passive boards. The drop simulation was conducted according to the JEDEC standard. It was revealed that the crack starting point related to failure fracture changed due to intermetallic phase transformation along the via interface, and the position where failure occurs experimentally agrees well with our simulation results.

  3. Resistance and resistance fluctuations in random resistor networks under biased percolation.

    Science.gov (United States)

    Pennetta, Cecilia; Reggiani, L; Trefán, Gy; Alfinito, E

    2002-06-01

    We consider a two-dimensional random resistor network (RRN) in the presence of two competing biased processes consisting of the breaking and recovering of elementary resistors. These two processes are driven by the joint effects of an electrical bias and of the heat exchange with a thermal bath. The electrical bias is set up by applying a constant voltage or, alternatively, a constant current. Monte Carlo simulations are performed to analyze the network evolution in the full range of bias values. Depending on the bias strength, electrical failure or steady state are achieved. Here we investigate the steady state of the RRN focusing on the properties of the non-Ohmic regime. In constant-voltage conditions, a scaling relation is found between /(0) and V/V(0), where is the average network resistance, (0) the linear regime resistance, and V0 the threshold value for the onset of nonlinearity. A similar relation is found in constant-current conditions. The relative variance of resistance fluctuations also exhibits a strong nonlinearity whose properties are investigated. The power spectral density of resistance fluctuations presents a Lorentzian spectrum and the amplitude of fluctuations shows a significant non-Gaussian behavior in the prebreakdown region. These results compare well with electrical breakdown measurements in thin films of composites and of other conducting materials.

  4. Experimental verification of temperature coefficients of resistance for uniformly doped P-type resistors in SOI

    International Nuclear Information System (INIS)

    Olszacki, M; Maj, C; Al Bahri, M; Marrot, J-C; Boukabache, A; Pons, P; Napieralski, A

    2010-01-01

    Many today's microsystems like strain-gauge-based piezoresistive pressure sensors contain doped resistors. If one wants to predict correctly the temperature impact on the performance of such devices, the accurate data about the temperature coefficients of resistance (TCR) are essential. Although such data may be calculated using one of the existing mobility models, our experiments showed that we can observe the huge mismatch between the calculated and measured values. Thus, in order to investigate the TCR values, a set of the test structures that contained doped P-type resistors was fabricated. As the TCR value also depends on the doping profile shape, we decided to use the very thin, 340 nm thick SOI wafers in order to fabricate the quasi-uniformly doped silicon layers ranging from 2 × 10 17 at cm −3 to 1.6 × 10 19 at cm −3 . The results showed that the experimental data for the first-order TCR are quite far from the calculated ones especially over the doping range of 10 18 –10 19 at cm −3 and quite close to the experimental ones obtained by Bullis about 50 years ago for bulk silicon. Moreover, for the first time, second-order coefficients that were not very consistent with the calculations were obtained.

  5. Relationship of end-expiratory pressure, lung volume, and /sup 99m/Tc-DTPA clearance

    International Nuclear Information System (INIS)

    Cooper, J.A.; van der Zee, H.; Line, B.R.; Malik, A.B.

    1987-01-01

    We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH 2 O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH 2 O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH 2 O PEEP. At 2.5 cmH 2 O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH 2 O (P less than 0.05). Between 15 and 20 cmH 2 O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized /sup 99m/Tc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation

  6. Positive expiratory pressure in patients with chronic obstructive pulmonary disease--a systematic review.

    Science.gov (United States)

    Fagevik Olsén, Monika; Westerdahl, Elisabeth

    2009-01-01

    Breathing exercises against a resistance during expiration are often used as treatment for patients with chronic obstructive pulmonary disease (COPD). Controversy still exists regarding the clinical application and efficacy. The aim of this systematic review was to determine the effects of chest physiotherapy techniques with positive expiratory pressure (PEP) for the prevention and treatment of pulmonary impairment in adults with COPD. The review was conducted on randomised, controlled clinical trials in which breathing exercises with positive expiratory pressure were compared with other chest physical therapy techniques or with no treatment, in adult patients with COPD. A computer-assisted literature search of available databases from 1970 to January 2008 was performed. Two reviewers extracted data independently and assessed the trials systematically with an instrument for measuring methodological quality. In total, 11 trials met the inclusion criteria, of which 5 reached an adequate level of internal validity. Several kinds of PEP techniques with a diversity of intensities and durations of treatment have been evaluated with different outcome measures and follow-up periods. Benefits of PEP were found in isolated outcome measures in separate studies with a follow-up period <1 month. Concerning long-term effects, the results are contradictory. Prior to widespread prescription of long-term PEP treatment, more research is required to establish the benefit of the technique in patients with COPD. (c) 2008 S. Karger AG, Basel.

  7. Effect of the radiofrequency volumetric tissue reduction of inferior turbinate on expiratory nasal sound frequency.

    Science.gov (United States)

    Seren, Erdal

    2009-01-01

    We sought to evaluate the short-term efficacy of radiofrequency volumetric tissue reduction (RFVTR) in treatment of inferior turbinate hypertrophy (TH) as measured by expiratory nasal sound spectra. In our study, we aimed to investigate the Odiosoft-rhino (OR) as a new diagnostic method to evaluate the nasal airflow of patients before and after RFVTR. In this study, we have analyzed and recorded the expiratory nasal sound in patients with inferior TH before and after RFVTR. This analysis includes the time expanded waveform, the spectral analysis with time averaged fast Fourier transform (FFT), and the waveform analysis of nasal sound. We found an increase in sound intensity at high frequency (Hf) in the sound analyses of the patients before RFVTR and a decrease in sound intensity at Hf was found in patients after RFVTR. This study indicates that RFVTR is an effective procedure to improve nasal airflow in the patients with nasal obstruction with inferior TH. We found significant decreases in the sound intensity level at Hf in the sound spectra after RFVTR. The OR results from the 2000- to 4000-Hz frequency (Hf) interval may be more useful in assessing patients with nasal obstruction than other frequency intervals. OR may be used as a noninvasive diagnostic tool to evaluate the nasal airflow.

  8. Control of positive end-expiratory pressure (PEEP for small animal ventilators

    Directory of Open Access Journals (Sweden)

    Leão Nunes Marcelo V

    2010-07-01

    Full Text Available Abstract Background The positive end-expiratory pressure (PEEP for the mechanical ventilation of small animals is frequently obtained with water seals or by using ventilators developed for human use. An alternative mechanism is the use of an on-off expiratory valve closing at the moment when the alveolar pressure is equal to the target PEEP. In this paper, a novel PEEP controller (PEEP-new and the PEEP system of a commercial small-animal ventilator, both based on switching an on-off valve, are evaluated. Methods The proposed PEEP controller is a discrete integrator monitoring the error between the target PEEP and the airways opening pressure prior to the onset of an inspiratory cycle. In vitro as well as in vivo experiments with rats were carried out and the PEEP accuracy, settling time and under/overshoot were considered as a measure of performance. Results The commercial PEEP controller did not pass the tests since it ignores the airways resistive pressure drop, resulting in a PEEP 5 cmH2O greater than the target in most conditions. The PEEP-new presented steady-state errors smaller than 0.5 cmH2O, with settling times below 10 s and under/overshoot smaller than 2 cmH2O. Conclusion The PEEP-new presented acceptable performance, considering accuracy and temporal response. This novel PEEP generator may prove useful in many applications for small animal ventilators.

  9. Airborne spread of expiratory droplet nuclei between the occupants of indoor environments: A review.

    Science.gov (United States)

    Ai, Z T; Melikov, A K

    2018-07-01

    This article reviews past studies of airborne transmission between occupants in indoor environments, focusing on the spread of expiratory droplet nuclei from mouth/nose to mouth/nose for non-specific diseases. Special attention is paid to summarizing what is known about the influential factors, the inappropriate simplifications of the thermofluid boundary conditions of thermal manikins, the challenges facing the available experimental techniques, and the limitations of available evaluation methods. Secondary issues are highlighted, and some new ways to improve our understanding of airborne transmission indoors are provided. The characteristics of airborne spread of expiratory droplet nuclei between occupants, which are influenced correlatively by both environmental and personal factors, were widely revealed under steady-state conditions. Owing to the different boundary conditions used, some inconsistent findings on specific influential factors have been published. The available instrumentation was too slow to provide accurate concentration profiles for time-dependent evaluations of events with obvious time characteristics, while computational fluid dynamics (CFD) studies were mainly performed in the framework of inherently steady Reynolds-averaged Navier-Stokes modeling. Future research needs in 3 areas are identified: the importance of the direction of indoor airflow patterns, the dynamics of airborne transmission, and the application of CFD simulations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Anisotropic generalization of Stinchcombe's solution for the conductivity of random resistor networks on a Bethe lattice

    Energy Technology Data Exchange (ETDEWEB)

    Semeriyanov, F; Saphiannikova, M; Heinrich, G [Leibniz Institute of Polymer Research Dresden, Hohe str. 6, 01069 Dresden (Germany)], E-mail: fsemeriyanov@yahoo.de

    2009-11-20

    Our study is based on the work of Stinchcombe (1974 J. Phys. C: Solid State Phys. 7 179) and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of the inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi (1974 Phys. Rev. B 9 4575) for the regular lattice.

  11. Arterial stick

    Science.gov (United States)

    ... be some throbbing. Why the Test Is Performed Blood transports oxygen, nutrients, waste products, and other materials within ... venous blood) mainly in its content of dissolved gases . Testing arterial blood shows the makeup of the blood before any ...

  12. Improvement in the voltage grading (axial and radial) of the generator column of a Van de Graaf generator by the use of a resistor chain

    International Nuclear Information System (INIS)

    Prabhakar, B.R.

    1977-01-01

    It is well known that the use of a series of resistors, connected between the equipotential rings of a Van de Graaff generator, improves the axial voltage grading of the generator. The work reported in this paper shows how the resistor chain also improves the radial voltage gradient. The electrolytic field mapping technique was adopted in the present work. (Auth.)

  13. Novel method for fabrication of integrated resistors on bilayer Ag/YBa2Cu3O7 films using Ni implantation

    International Nuclear Information System (INIS)

    LaGraff, J.R.; Chan, H.; Murduck, J.M.; Hong, S.H.; Ma, Q.Y.

    1997-01-01

    A novel ion implantation method is described for fabricating low inductance integrated resistors on Ag/YBa 2 Cu 3 O 7 (YBCO) bilayer thin films. Parallel high and low value resistors were simultaneously formed by patterning bilayer films into 10-μm-wide lines, then masking and implanting with Ni to selectively inhibit superconductivity in YBCO. Low value resistors (<1Ω/sq) were formed at 77 K as the supercurrent bypassed the Ni-doped nonsuperconducting YBCO and was shunted through the overlying low resistivity Ag metal. High value resistors (20 - 140 Ω/sq) were formed by removing Ag from above the implanted YBCO forcing the current through the implanted YBCO region. The sheet resistance of both types of resistors was found to increase systematically with increasing Ni implant energy. copyright 1997 American Institute of Physics

  14. Cystic Fibrosis: Are Volumetric Ultra-Low-Dose Expiratory CT Scans Sufficient for Monitoring Related Lung Disease?

    DEFF Research Database (Denmark)

    Loeve, Martine; Lequin, Maarten H; Bruijne, Marleen de

    2009-01-01

    Purpose: To assess whether chest computed tomography (CT) scores from ultra-low-dose end-expiratory scans alone could suffice for assessment of all cystic fibrosis (CF)-related structural lung abnormalities. Materials and Methods: In this institutional review board–approved study, 20 patients...... with CF aged 6–20 years (eight males, 12 females) underwent low-dose end-inspiratory CT and ultra-low-dose end-expiratory CT. Informed consent was obtained. Scans were randomized and scored by using the Brody-II CT scoring system to assess bronchiectasis, airway wall thickening, mucus plugging......-Altman plots. Results: Median age was 12.6 years (range, 6.3–20.3 years), median forced expiratory volume in 1 second was 100% (range, 46%–127%) of the predicted value, and median forced vital capacity was 99% (range, 61%–123%) of the predicted value. Very good agreement was observed between end...

  15. Effect of simultaneous application of postural techniques and expiratory muscle strength training on the enhancement of the swallowing function of patients with dysphagia caused by parkinson's disease.

    Science.gov (United States)

    Byeon, Haewon

    2016-06-01

    [Purpose] This study aimed to investigate the effect of simultaneous application of postural techniques and expiratory muscle strength training on the enhancement of the swallowing function of patients with dysphagia caused by Parkinson's disease. [Subjects and Methods] The subjects of this study were 18 patients who received simultaneous application of postural techniques and expiratory muscle strength training and 15 patients who received expiratory muscle strength training only. Postural techniques were conducted in the order of chin tucking, head rotation, head tilting, bending head back, and lying down, while expiratory muscle strength training was conducted at a resistance level of about 70% of the maximal expiratory pressure. Swallowing recovery was assessed by using the Functional Dysphagia Scale based on videofluoroscopic studies. [Results] The mean value obtained in the videofluoroscopic studies for both groups decreased after the treatment. In the postural techniques plus expiratory muscle strength training group, the decrease was significantly greater than that in the expiratory muscle strength training-only group. [Conclusion] The results imply that simultaneous performance of postural techniques and expiratory muscle strength training is more effective than expiratory muscle strength training alone when applied in the swallowing rehabilitation for patients with dysphagia caused by Parkinson's disease.

  16. Arterial stiffness

    Directory of Open Access Journals (Sweden)

    Ursula Quinn

    2012-09-01

    Full Text Available Measurements of biomechanical properties of arteries have become an important surrogate outcome used in epidemiological and interventional cardiovascular research. Structural and functional differences of vessels in the arterial tree result in a dampening of pulsatility and smoothing of blood flow as it progresses to capillary level. A loss of arterial elastic properties results a range of linked pathophysiological changes within the circulation including increased pulse pressure, left ventricular hypertrophy, subendocardial ischaemia, vessel endothelial dysfunction and cardiac fibrosis. With increased arterial stiffness, the microvasculature of brain and kidneys are exposed to wider pressure fluctuations and may lead to increased risk of stroke and renal failure. Stiffening of the aorta, as measured by the gold-standard technique of aortic Pulse Wave Velocity (aPWV, is independently associated with adverse cardiovascular outcomes across many different patient groups and in the general population. Therefore, use of aPWV has been proposed for early detection of vascular damage and individual cardiovascular risk evaluation and it seems certain that measurement of arterial stiffness will become increasingly important in future clinical care. In this review we will consider some of the pathophysiological processes that result from arterial stiffening, how it is measured and factors that may drive it as well as potential avenues for therapy. In the face of an ageing population where mortality from atheromatous cardiovascular disease is falling, pathology associated with arterial stiffening will assume ever greater importance. Therefore, understanding these concepts for all clinicians involved in care of patients with cardiovascular disease will become vital.

  17. Suppression of Adverse Effects of GIC Using Controlled Variable Grounding Resistor

    Science.gov (United States)

    Abuhussein, A.; Ali, M. H.

    2016-12-01

    Geomagnetically induced current (GIC) has a harmful impact on power systems, with a large footprint. Mitigation strategies for the GIC are required to protect the integrity of the power system. To date, the adverse effects of GIC are being mitigated by either operational procedures or grounding fixed capacitors (GFCs). The operational procedures are uncertain, reduce systems' reliability, and increase energy losses. On the other hand, GFCs, incur voltage spikes, increase the transformer cost substantially, and require protection circuitry. This study investigates new possible approaches to cope with GIC, by using a controlled variable grounding resistor (CVGR), without interfering with the system's normal operation. In addition, the new techniques help suppress unsymmetrical faults in the power network. The controllability of the grounding resistor is applied using three different techniques: (1) a Parallel switch that is controlled by PI regulated duty cycle, (2) a Parallel switch that is triggered by a preset values in a look-up-table (LUT), and (3) a Mechanical resistor varied by a Fuzzy logic controller (FLC). The experimental results were obtained and validated using the MATLAB/SIMULINK software. A hypothetical power system that consists of a generator, a 765kv, 500 km long transmission lines connecting between a step-up, Δ-Yn, transformer, and a step-down, Yn-Δ, transformer, is considered. The performance of the CVGR is compared with that of the GFC under the cases of GIC event and unsymmetrical faults. From the simulation results, the following points are concluded: The CVGR effectively suppresses the GIC flowing in the system. Consequently, it protects the transformers from saturation and the rest of the system from collapsing. The CVGR also reduces the voltage and power swings associated with unsymmetrical faults and blocks the zero sequence current flowing through the neutral of the transformer. The performance of the CVGR surpasses that of the GFC in

  18. TU-CD-BRA-11: Application of Bone Suppression Technique to Inspiratory/expiratory Chest Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, R; Sanada, S [Kanazawa University, Kanazawa, Ishikawa (Japan); Sakuta, K; Kawashima, H [Kanazawa University Hospital, Kanazawa, Ishikawa (Japan); Kishitani, Y [TOYO Corporation, Chuoh-ku, Tokyo (Japan)

    2015-06-15

    Purpose: The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images normally obtained by the dual-energy subtraction technique. This study was performed to investigate the usefulness of bone suppression technique in quantitative analysis of pulmonary function in inspiratory/expiratory chest radiography. Methods: Commercial bone suppression image processing software (ClearRead; Riverain Technologies) was applied to paired inspiratory/expiratory chest radiographs of 107 patients (normal, 33; abnormal, 74) to create corresponding bone suppression images. The abnormal subjects had been diagnosed with pulmonary diseases, such as pneumothorax, pneumonia, emphysema, asthma, and lung cancer. After recognition of the lung area, the vectors of respiratory displacement were measured in all local lung areas using a cross-correlation technique. The measured displacement in each area was visualized as displacement color maps. The distribution pattern of respiratory displacement was assessed by comparison with the findings of lung scintigraphy. Results: Respiratory displacement of pulmonary markings (soft tissues) was able to be quantified separately from the rib movements on bone suppression images. The resulting displacement map showed a left-right symmetric distribution increasing from the lung apex to the bottom region of the lung in many cases. However, patients with ventilatory impairments showed a nonuniform distribution caused by decreased displacement of pulmonary markings, which were confirmed to correspond to area with ventilatory impairments found on the lung scintigrams. Conclusion: The bone suppression technique was useful for quantitative analysis of respiratory displacement of pulmonary markings without any interruption of the rib shadows. Abnormal areas could be detected as decreased displacement of pulmonary markings. Inspiratory/expiratory chest radiography combined

  19. An expiratory assist during spontaneous breathing can compensate for endotracheal tube resistance.

    Science.gov (United States)

    Uchiyama, Akinori; Chang, Cheng; Suzuki, Shinya; Mashimo, Takashi; Fujino, Yuji

    2009-08-01

    Although inspiratory assist of spontaneous breathing in intubated patients is common, expiratory assist functions have rarely been reported. Effective expiratory support (ES) could be used to compensate for endotracheal tube (ETT) resistance during spontaneous breathing. In this study, we examined the performance of a new system designed to provide both inspiratory support (IS) and ES during spontaneous breathing with the goal of reducing the effective resistance of the ETT. The ES system consisted of a ventilator demand valve and a computer-controlled piston cylinder, which aspirated gas from the respiratory circuit during the expiratory phase. The movement of the piston was synchronized with spontaneous breathing. We compared the pressures at the tip of the ETT and in the breathing circuit during spontaneous breathing through an ETT of internal diameter (ID) 5 mm with that of an ETT with ID 8 mm in nine healthy adult male volunteers. The ventilatory mode was set to maintain a continuous airway pressure of 0 cm H(2)O. Three ventilator settings (no support, IS only, and IS plus ES) were compared using ID 5 mm ETT. We monitored pressure in the breathing circuit (P(aw)), ETT tip pressure (P(tip)), and respiratory flow. The P(tip) of the ID 5 mm ETT showed a large negative deflection during inspiration and a positive deflection during expiration without support. IS alone did not improve the respiratory pattern through the small ETT. However, IS plus ES resulted in negative P(aw) during expiration in addition to positive deflection of P(aw) during inspiration, making the pressure characteristics of P(tip) similar to those of ID 8 mm ETT. Moreover, IS plus ES produced a respiratory pattern through the ID 5 mm ETT that was similar to that through the ID 8 mm ETT. In this study of healthy volunteers, IS plus ES compensated for the airway resistance imposed by a ID 5.0 mm ETT to create pressure changes at the tip of the ETT similar to those of an ID 8.0 mm ETT.

  20. Carotid artery surgery

    Science.gov (United States)

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  1. Cross-Bridge Kelvin resistor structures for reliable measurement of low contact resistances and contact interface characterization

    NARCIS (Netherlands)

    Stavitski, N.; Klootwijk, J.H.; van Zeijl, H.W.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2009-01-01

    The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (�?�c) have been extensively discussed during last few decades and the minimum of the �?�c value, which could be accurately extracted, was

  2. A novel Silicon Photomultiplier with bulk integrated quench resistors: utilization in optical detection and tracking applications for particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Petrovics, Stefan, E-mail: stp@hll.mpg.de [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Andricek, Ladislav [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Diehl, Inge; Hansen, Karsten [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Jendrysik, Christian [Infineon Technologies AG, Am Campeon 1-12, D-85579 Neubiberg (Germany); Krueger, Katja [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Lehmann, Raik; Ninkovic, Jelena [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Reckleben, Christian [DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Richter, Rainer; Schaller, Gerhard; Schopper, Florian [Halbleiterlabor der Max-Planck Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Sefkow, Felix [DESY, Notkestrasse 85, D-22607 Hamburg (Germany)

    2017-02-11

    Silicon Photomultipliers (SiPMs) are a promising candidate for replacing conventional photomultiplier tubes (PMTs) in many applications, thanks to ongoing developments and advances in their technology. Conventional SiPMs are generally an array of avalanche photo diodes, operated in Geiger mode and read out in parallel, thus leading to the necessity of a high ohmic quenching resistor. This resistor enables passive quenching and is usually located on top of the array, limiting the fill factor of the device. In this paper, a novel detector concept with a bulk integrated quenching resistor will be recapped. In addition, due to other advantages of this novel detector design, a new concept, in which these devices will be utilized as tracking detectors for particle physics applications will be introduced, as well as first simulation studies and experimental measurements of this new approach. - Highlights: • A novel SiPM concept with bulk integrated quenching resistor is shown. • First prototypes of these SiPMs as tracking detectors are proposed. • Simulations of the Geiger efficiency suggest feasible operations at low overbias. • First measurements of the electron detection efficiency show promising results. • Measurements are in good agreement with the simulations.

  3. Technical-economic evaluation of the utilization of closing resistor in CEMIG extra-high voltage circuit breakers

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Angelica C.O.; Pinto, Roberto del Giudice R.; Teixeira, Jose Cleber; Fonseca, Rodrigo Assuncao; F, Junior, Sebastiao V [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

    1994-12-31

    This paper presents the technical and economic studies performed by CEMIG, Companhia Energetica de Minas Gerais, Brazil, concerning the use of closing resistor in its extra-high voltage (EHV) breakers. The analysis emphasizes the advantages which could be achieved with the elimination of the resistor as far as costs and reliability are concerned. This evaluation was motivated by two 500 kV breaker failures resulting from the breakdown of the closing resistor operation mechanism. These occurrences resulted in operative restriction for CEMIG EHV system. The analysis demanded a review of the capability criteria of silicon carbide (Si C) gap arresters, which are still greatly used in CEMIG EHV System, and of the procedures to be applied when carrying out the transient studies. The investigation resulted in the prompt removal of closing resistors from circuit breakers in CEMIG extra-high voltage system generating an economy of approximately U$ 840,00 and an improvement in safety and system reliability. (author) 13 refs., 4 figs., 1 tab.

  4. Flexible and twistable non-volatile memory cell array with all-organic one diode-one resistor architecture.

    Science.gov (United States)

    Ji, Yongsung; Zeigler, David F; Lee, Dong Su; Choi, Hyejung; Jen, Alex K-Y; Ko, Heung Cho; Kim, Tae-Wook

    2013-01-01

    Flexible organic memory devices are one of the integral components for future flexible organic electronics. However, high-density all-organic memory cell arrays on malleable substrates without cross-talk have not been demonstrated because of difficulties in their fabrication and relatively poor performances to date. Here we demonstrate the first flexible all-organic 64-bit memory cell array possessing one diode-one resistor architectures. Our all-organic one diode-one resistor cell exhibits excellent rewritable switching characteristics, even during and after harsh physical stresses. The write-read-erase-read output sequence of the cells perfectly correspond to the external pulse signal regardless of substrate deformation. The one diode-one resistor cell array is clearly addressed at the specified cells and encoded letters based on the standard ASCII character code. Our study on integrated organic memory cell arrays suggests that the all-organic one diode-one resistor cell architecture is suitable for high-density flexible organic memory applications in the future.

  5. Peak expiratory flow rate in healthy children aged 6-17 years

    DEFF Research Database (Denmark)

    Høst, A; Høst, A H; Ibsen, T

    1994-01-01

    Peak expiratory flow rate (PEFR) was measured in a cross-sectional study in 861 healthy Danish schoolchildren aged 6-17 years using a Mini Wright peak flowmeter. We found a strong correlation between PEFR and height, age and sex. The results were comparable with those from previous studies using...... a Wright peak flowmeter. The equation for prediction of PEFR in boys was calculated as (3.8 x height) + (10.6 x age) - 313.2 (p age) - 143.9 (p ... coefficient in this large sample. Among healthy children without previous asthma, earlier episodes of recurrent wheezing were reported in 8.8% and a significantly lower PEFR was found in this group....

  6. Two-point resistance of a resistor network embedded on a globe.

    Science.gov (United States)

    Tan, Zhi-Zhong; Essam, J W; Wu, F Y

    2014-07-01

    We consider the problem of two-point resistance in an (m-1) × n resistor network embedded on a globe, a geometry topologically equivalent to an m × n cobweb with its boundary collapsed into one single point. We deduce a concise formula for the resistance between any two nodes on the globe using a method of direct summation pioneered by one of us [Z.-Z. Tan, L. Zhou, and J. H. Yang, J. Phys. A: Math. Theor. 46, 195202 (2013)]. This method is contrasted with the Laplacian matrix approach formulated also by one of us [F. Y. Wu, J. Phys. A: Math. Gen. 37, 6653 (2004)], which is difficult to apply to the geometry of a globe. Our analysis gives the result in the form of a single summation.

  7. A Novel Read Scheme for Large Size One-Resistor Resistive Random Access Memory Array.

    Science.gov (United States)

    Zackriya, Mohammed; Kittur, Harish M; Chin, Albert

    2017-02-10

    The major issue of RRAM is the uneven sneak path that limits the array size. For the first time record large One-Resistor (1R) RRAM array of 128x128 is realized, and the array cells at the worst case still have good Low-/High-Resistive State (LRS/HRS) current difference of 378 nA/16 nA, even without using the selector device. This array has extremely low read current of 9.7 μA due to both low-current RRAM device and circuit interaction, where a novel and simple scheme of a reference point by half selected cell and a differential amplifier (DA) were implemented in the circuit design.

  8. Resistor mesh model of a spherical head: part 2: a review of applications to cortical mapping.

    Science.gov (United States)

    Chauveau, N; Morucci, J P; Franceries, X; Celsis, P; Rigaud, B

    2005-11-01

    A resistor mesh model (RMM) has been validated with reference to the analytical model by consideration of a set of four dipoles close to the cortex. The application of the RMM to scalp potential interpolation was detailed in Part 1. Using the RMM and the same four dipoles, the different methods of cortical mapping were compared and have shown the potentiality of this RMM for obtaining current and potential cortical distributions. The lead-field matrices are well-adapted tools, but the use of a square matrix of high dimension does not permit the inverse solution to be improved in the presence of noise, as a regularisation technique is necessary with noisy data. With the RMM, the transfer matrix and the cortical imaging technique proved to be easy to implement. Further development of the RMM will include application to more realistic head models with more accurate conductivities.

  9. Resistor-logic demultiplexers for nanoelectronics based on constant-weight codes.

    Science.gov (United States)

    Kuekes, Philip J; Robinett, Warren; Roth, Ron M; Seroussi, Gadiel; Snider, Gregory S; Stanley Williams, R

    2006-02-28

    The voltage margin of a resistor-logic demultiplexer can be improved significantly by basing its connection pattern on a constant-weight code. Each distinct code determines a unique demultiplexer, and therefore a large family of circuits is defined. We consider using these demultiplexers for building nanoscale crossbar memories, and determine the voltage margin of the memory system based on a particular code. We determine a purely code-theoretic criterion for selecting codes that will yield memories with large voltage margins, which is to minimize the ratio of the maximum to the minimum Hamming distance between distinct codewords. For the specific example of a 64 × 64 crossbar, we discuss what codes provide optimal performance for a memory.

  10. Logarithmic corrections to scaling in critical percolation and random resistor networks.

    Science.gov (United States)

    Stenull, Olaf; Janssen, Hans-Karl

    2003-09-01

    We study the critical behavior of various geometrical and transport properties of percolation in six dimensions. By employing field theory and renormalization group methods we analyze fluctuation induced logarithmic corrections to scaling up to and including the next-to-leading order correction. Our study comprehends the percolation correlation function, i.e., the probability that two given points are connected, and some of the fractal masses describing percolation clusters. To be specific, we calculate the mass of the backbone, the red bonds, and the shortest path. Moreover, we study key transport properties of percolation as represented by the random resistor network. We investigate the average two-point resistance as well as the entire family of multifractal moments of the current distribution.

  11. Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.

    Science.gov (United States)

    Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

    2013-10-04

    Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry.

  12. The 'emergent scaling' phenomenon and the dielectric properties of random resistor-capacitor networks

    CERN Document Server

    Bouamrane, R

    2003-01-01

    An efficient algorithm, based on the Frank-Lobb reduction scheme, for calculating the equivalent dielectric properties of very large random resistor-capacitor (R-C) networks has been developed. It has been used to investigate the network size and composition dependence of dielectric properties and their statistical variability. The dielectric properties of 256 samples of random networks containing: 512, 2048, 8192 and 32 768 components distributed randomly in the ratios 60% R-40% C, 50% R-50% C and 40% R-60% C have been computed. It has been found that these properties exhibit the anomalous power law dependences on frequency known as the 'universal dielectric response' (UDR). Attention is drawn to the contrast between frequency ranges across which percolation determines dielectric response, where considerable variability is found amongst the samples, and those across which power laws define response where very little variability is found between samples. It is concluded that the power law UDRs are emergent pr...

  13. Validity of peak expiratory flow measurement in assessing reversibility of airflow obstruction.

    Science.gov (United States)

    Dekker, F W; Schrier, A C; Sterk, P J; Dijkman, J H

    1992-01-01

    BACKGROUND: Assessing the reversibility of airflow obstruction by peak expiratory (PEF) measurements would be practicable in general practice, but its usefulness has not been investigated. METHODS: PEF measurements were performed (miniWright peak flow meter) in 73 general practice patients (aged 40 to 84) with a history of asthma or chronic obstructive lung disease before and after 400 micrograms inhaled sulbutamol. The change in PEF was compared with the change in forced expiratory volume in one second (FEV1). Reversible airflow obstruction was analysed in two ways according to previous criteria. When defined as a 9% or greater increase in FEV1 expressed as a percentage of predicted values reversibility was observed in 42% of patients. Relative operating characteristic analysis showed that an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (the sensitivity and specificity of an increase of 60 l/min in detecting a 9% or more increase in FEV1 as a percentage of predicted values were 68% and 93% respectively, with a positive predictive value of 87%). When defined as an increase of 190 ml or more in FEV1, reversible airflow obstruction was observed in 53% of patients. Again an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (sensitivity 56%, specificity 94%, and positive predictive value 92%). CONCLUSION: Absolute changes in PEF can be used as a simple technique to diagnose reversible airflow obstruction in patients from general practice. PMID:1519192

  14. Measurement of small ion beams by thermal ionisation mass spectrometry using new 10(13) Ohm resistors.

    Science.gov (United States)

    Koornneef, J M; Bouman, C; Schwieters, J B; Davies, G R

    2014-03-28

    We tested 5 newly manufactured - prototype - 10(13)Ohm resistors in the feedback loop of Faraday cup amplifiers to measure small ion beams by Thermal Ionisation Mass Spectrometry (TIMS). The high Ohmic resistors installed in the TRITON Plus at the VU University Amsterdam theoretically have 10 times lower noise levels relative to the default 10(11)Ohm resistors. To investigate the precision and accuracy of analyses using these new amplifiers we measured Sr and Nd isotopes of reference standards at a range of ion currents (3.2×10(-16) to 1×10(-12) A, corresponding to intensities of 32 μV to 100 mV on a default 10(11)Ohm amplifier) and on small amounts of material (100 and 10 pg). Internal precision and external reproducibility for Sr and Nd isotope ratios are both better when collected on 10(13) compared 10(12)Ohm resistors and to the default 10(11)Ohm resistors. At an (87)Sr ion current of 3×10(-14) A (3 mV on a 10(11)Ohm amplifier) the internal precision (2 SE) of (87)Sr/(86)Sr is 5 times better for 10(13)Ohm resistors compared to 10(11)Ohm resistors. The external reproducibility (2 SD) at this beam intensity is 9 times better. Multiple 100 and 10 pg Sr standards, ran to exhaustion, yielded low (87)Sr/(86)Sr compared to the long term average (e.g. 10 pg average=0.710083±164 (n=11) instead of 0.710244±12, n=73). The average off-set for 10 pg standards can be explained by a loading blank contribution of 1.3 pg. In contrast, Nd data on 100 pg and 10 pg samples are accurate suggesting that Nd loading blanks do not compromise the data. The external reproducibility of (143)Nd/(144)Nd on 100 pg samples is 125 ppm and 3.3‰ on 10 pg samples (2 RSD=relative standard deviation, n=10). Thus, variability in Nd and Sr isotope ratios in the 4th decimal place, e.g. (143)Nd/(144)Nd 0.5110-0.5119 or (87)Sr/(86)Sr 0.7100-0.7109, can be resolved in 10 to 100 pg samples provided that the procedural blanks and chemical separation are optimal. For measurements in the beam

  15. Thermocapillary actuation by optimized resistor pattern: bubbles and droplets displacing, switching and trapping.

    Science.gov (United States)

    Selva, Bertrand; Miralles, Vincent; Cantat, Isabelle; Jullien, Marie-Caroline

    2010-07-21

    We report a novel method for bubble or droplet displacement, capture and switching within a bifurcation channel for applications in digital microfluidics based on the Marangoni effect, i.e. the appearance of thermocapillary tangential interface stresses stemming from local surface tension variations. The specificity of the reported actuation is that heating is provided by an optimized resistor pattern (B. Selva, J. Marchalot and M.-C. Jullien, An optimized resistor pattern for temperature gradient control in microfluidics, J. Micromech. Microeng., 2009, 19, 065002) leading to a constant temperature gradient along a microfluidic cavity. In this context, bubbles or droplets to be actuated entail a surface force originating from the thermal Marangoni effect. This actuator has been characterized (B. Selva, I. Cantat, and M.-C. Jullien, Migration of a bubble towards a higher surface tension under the effect of thermocapillary stress, preprint, 2009) and it was found that the bubble/droplet (called further element) is driven toward a high surface tension region, i.e. toward cold region, and the element velocity increases while decreasing the cavity thickness. Taking advantage of these properties three applications are presented: (1) element displacement, (2) element switching, detailed in a given range of working, in which elements are redirected towards a specific evacuation, (3) a system able to trap, and consequently stop on demand, the elements on an alveolus structure while the continuous phase is still flowing. The strength of this method lies in its simplicity: single layer system, in situ heating leading to a high level of integration, low power consumption (P < 0.4 W), low applied voltage (about 10 V), and finally this system is able to manipulate elements within a flow velocity up to 1 cm s(-1).

  16. Pulmonary emphysema quantitation with Computed Tomography. Comparison between the visual score with high resolution CT, expiratory density mask with spiral CT and lung function studies

    International Nuclear Information System (INIS)

    Zompatori, Maurizio; Battaglia, Milva; Rimondi, Maria Rita; Vivacqua, Donatella; Biscarini, Manuela; Fasano, Luca; Pacilli, Angela Maria Grazia; Guerrieri, Aldo; Fabbri, Mario; Cavina, Mauro

    1997-01-01

    CT is the most accurate method to detect pulmonary emphysema in vivo. They compared prospectively two different methods for emphysema quantitation in 5 normal volunteers and 20 consecutive patients with chronic obstructive pulmonary disease (COPD). All subjects were submitted to function tests and HRCT; three scans were acquired at preselected levels during inspiration. The type and extent of pulmonary emphysema were defined by two independent observers under blind conditions. Disagreements were subsequently settled by consent. All subjects were also examined with expiratory spiral CT using a density mask program, at two different cut-off levels (-850,-900 HU). Visual score and expiratory spiral density mask values (-850 HU) were significantly correlated (r = 0.86), but the visual extent of emphysema was always higher than shown by expiratory spiral CT. The emphysema extent assessed with both CT methods correlated with the function result of expiratory airflow obstruction and gas diffusion impairment (visual score versus forced expiratory volume in one second: r = -0.81, versus single breath carbon monoxide diffusion: r = -0.78. Spiral expiratory density mask -850 HU versus forced expiratory volume in one second: r = -0.85 versus single breath carbon monoxide diffusion: r = -0.77). When -900 HU was used as the cut-off value for the expiratory density mask, the correlation with single breath carbon monoxide diffusion worsened (r = -0.56). Visual score and expiratory density mask -850 HU gave similar results and permitted COPD patients to be clearly distinguished from normal controls (p < 0.01). They believe the true residual volume should lie somewhere in between the CT value and the function results with the helium dilution technique and conclude that the extent of pulmonary emphysema can be confidently assessed with CT methods. Finally, the simple visual score may be as reliable as such highly sophisticated new methods as the spiral expiratory density mask

  17. Electrical properties of nano-resistors made from the Zr-doped HfO2 high-k dielectric film

    Science.gov (United States)

    Zhang, Shumao; Kuo, Yue

    2018-03-01

    Electrical properties of nano-sized resistors made from the breakdown of the metal-oxide-semiconductor capacitor composed of the amorphous high-k gate dielectric have been investigated under different stress voltages and temperatures. The effective resistance of nano-resistors in the device was estimated from the I-V curve in the high voltage range. It decreased with the increase of the number of resistors. The resistance showed complicated temperature dependence, i.e. it neither behaves like a conductor nor a semiconductor. In the low voltage operation range, the charge transfer was controlled by the Schottky barrier at the nano-resistor/Si interface. The barrier height decreased with the increase of stress voltage, which was probably caused by the change of the nano-resistor composition. Separately, it was observed that the barrier height was dependent on the temperature, which was probably due to the dynamic nano-resistor formation process and the inhomogeneous barrier height distribution. The unique electrical characteristics of this new type of nano-resistors are important for many electronic and optoelectronic applications.

  18. Arterial embolism

    Science.gov (United States)

    ... when a clot in a vein enters the right side of the heart and passes through a hole into the left side. The clot can then move to an artery and block blood flow to the brain (stroke) or other organs. If a clot involves ...

  19. Positive end-expiratory pressure improves survival in a rodent model of cardiopulmonary resuscitation using high-dose epinephrine.

    LENUS (Irish Health Repository)

    McCaul, Conán

    2009-10-01

    Multiple interventions have been tested in models of cardiopulmonary resuscitation (CPR) to optimize drug use, chest compressions, and ventilation. None has studied the effects of positive end-expiratory pressure (PEEP) on outcome. We hypothesized that because PEEP can reverse pulmonary atelectasis, lower pulmonary vascular resistance, and potentially improve cardiac output, its use during CPR would increase survival.

  20. Nebulized hypertonic saline via positive expiratory pressure versus via jet nebulizer in patients with severe cystic fibrosis.

    LENUS (Irish Health Repository)

    O'Connell, Oisin J

    2011-06-01

    Nebulized hypertonic saline is a highly effective therapy for patients with cystic fibrosis (CF), yet 10% of patients are intolerant of hypertonic saline administered via jet nebulizer. Positive expiratory pressure (PEP) nebulizers splint open the airways and offers a more controlled rate of nebulization.

  1. Protein losing enteropathy secondary to a pulmonary artery stent

    Directory of Open Access Journals (Sweden)

    Narayanswami Sreeram

    2012-01-01

    Full Text Available A 2-year-old patient with hypoplastic left heart syndrome presented 6 months following Fontan completion with protein-losing enteropathy (PLE. He had undergone stent implantation in the left pulmonary artery after the Norwood procedure, followed by redilation of the stent prior to Fontan completion. Combined bronchoscopic and catheterization studies during spontaneous breathing confirmed left bronchial stenosis behind the stent, and diastolic systemic ventricular pressure during expiration of 25 mm Hg. We postulate that the stent acts as a valve, against which the patient generates high expiratory pressures, which are reflected in the ventricular diastolic pressure. This may be the cause of PLE.

  2. Respiratory System Mechanics During Low Versus High Positive End-Expiratory Pressure in Open Abdominal Surgery: A Substudy of PROVHILO Randomized Controlled Trial

    NARCIS (Netherlands)

    D'Antini, Davide; Huhle, Robert; Herrmann, Jacob; Sulemanji, Demet S.; Oto, Jun; Raimondo, Pasquale; Mirabella, Lucia; Hemmes, Sabrine N. T.; Schultz, Marcus J.; Pelosi, Paolo; Kaczka, David W.; Vidal Melo, Marcos Francisco; Gama de Abreu, Marcelo; Cinnella, Gilda

    2018-01-01

    In the 2014 PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure (PROVHILO) trial, intraoperative low tidal volume ventilation with high positive end-expiratory pressure (PEEP = 12 cm H2O) and lung recruitment maneuvers did not decrease postoperative pulmonary complications

  3. Analyses of power output of piezoelectric energy-harvesting devices directly connected to a load resistor using a coupled piezoelectric-circuit finite element method.

    Science.gov (United States)

    Zhu, Meiling; Worthington, Emma; Njuguna, James

    2009-07-01

    This paper presents, for the first time, a coupled piezoelectric-circuit finite element model (CPC-FEM) to analyze the power output of a vibration-based piezoelectric energy-harvesting device (EHD) when it is connected to a load resistor. Special focus is given to the effect of the load resistor value on the vibrational amplitude of the piezoelectric EHD, and thus on the current, voltage, and power generated by the device, which are normally assumed to be independent of the load resistor value to reduce the complexity of modeling and simulation. The presented CPC-FEM uses a cantilever with a sandwich structure and a seismic mass attached to the tip to study the following characteristics of the EHD as a result of changing the load resistor value: 1) the electric outputs: the current through and voltage across the load resistor; 2) the power dissipated by the load resistor; 3) the displacement amplitude of the tip of the cantilever; and 4) the shift in the resonant frequency of the device. It is found that these characteristics of the EHD have a significant dependence on the load resistor value, rather than being independent of it as is assumed in most literature. The CPC-FEM is capable of predicting the generated output power of the EHD with different load resistor values while simultaneously calculating the effect of the load resistor value on the displacement amplitude of the tip of the cantilever. This makes the CPC-FEM invaluable for validating the performance of a designed EHD before it is fabricated and tested, thereby reducing the recurring costs associated with repeat fabrication and trials. In addition, the proposed CPC-FEM can also be used for producing an optimized design for maximum power output.

  4. Dangerous Pressurization and Inappropriate Alarms during Water Occlusion of the Expiratory Circuit of Commonly Used Infant Ventilators.

    Directory of Open Access Journals (Sweden)

    Murray Hinder

    Full Text Available Non-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or 'rainout' from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected and excessive repetitive airway pressurisation in a Draeger VN500 prompted a systematic bench test examination of currently available ventilators.To assess neonatal ventilator response to partial or complete expiratory limb occlusion when set to non-invasive continuous positive airway pressure mode.Seven commercially available neonatal ventilators connected to a test lung using a standard infant humidifier circuit with partial and/or complete expiratory limb occlusion were examined in a bench test study. Each ventilator was set to deliver 6 cmH2O in non-invasive mode and respiratory mechanics data for 75%, 80% and 100% occlusion were collected.Several ventilators responded inappropriately with complete occlusion by cyclical pressurisation/depressurisation to peak pressures of between 19·4 and 64·6 cm H2O at rates varying between 2 to 77 inflations per minute. Tidal volumes varied between 10·1 and 24·3mL. Alarm responses varied from 'specific' (tube occluded to 'ambiguous' (Safety valve open. Carefusion Avea responded by continuing to provide the set distending pressure and displaying an appropriate alarm message. Draeger Babylog 8000 did not alarm with partial occlusions and incorrectly displayed airways pressure at 6·1cmH2O compared to the measured values of 13cmH2O.This study found a potential for significant adverse ventilator response due to complete or near complete expiratory limb occlusion in CPAP mode.

  5. Diagnosis of bronchiectasis and airway wall thickening in children with cystic fibrosis. Objective airway-artery quantification

    International Nuclear Information System (INIS)

    Kuo, Wieying; Tiddens, Harm A.W.M.; Bruijne, Marleen de; Petersen, Jens; Nasserinejad, Kazem; Ozturk, Hadiye; Chen, Yong; Perez-Rovira, Adria

    2017-01-01

    To quantify airway and artery (AA)-dimensions in cystic fibrosis (CF) and control patients for objective CT diagnosis of bronchiectasis and airway wall thickness (AWT). Spirometer-guided inspiratory and expiratory CTs of 11 CF and 12 control patients were collected retrospectively. Airway pathways were annotated semi-automatically to reconstruct three-dimensional bronchial trees. All visible AA-pairs were measured perpendicular to the airway axis. Inner, outer and AWT (outer-inner) diameter were divided by the adjacent artery diameter to compute A in A-, A out A- and A WT A-ratios. AA-ratios were predicted using mixed-effects models including disease status, lung volume, gender, height and age as covariates. Demographics did not differ significantly between cohorts. Mean AA-pairs CF: 299 inspiratory; 82 expiratory. Controls: 131 inspiratory; 58 expiratory. All ratios were significantly larger in inspiratory compared to expiratory CTs for both groups (p<0.001). A out A- and A WT A-ratios were larger in CF than in controls, independent of lung volume (p<0.01). Difference of A out A- and A WT A-ratios between patients with CF and controls increased significantly for every following airway generation (p<0.001). Diagnosis of bronchiectasis is highly dependent on lung volume and more reliably diagnosed using outer airway diameter. Difference in bronchiectasis and AWT severity between the two cohorts increased with each airway generation. (orig.)

  6. The classical Starling resistor model often does not predict inspiratory airflow patterns in the human upper airway.

    Science.gov (United States)

    Owens, Robert L; Edwards, Bradley A; Sands, Scott A; Butler, James P; Eckert, Danny J; White, David P; Malhotra, Atul; Wellman, Andrew

    2014-04-15

    The upper airway is often modeled as a classical Starling resistor, featuring a constant inspiratory airflow, or plateau, over a range of downstream pressures. However, airflow tracings from clinical sleep studies often show an initial peak before the plateau. To conform to the Starling model, the initial peak must be of small magnitude or dismissed as a transient. We developed a method to simulate fast or slow inspirations through the human upper airway, to test the hypothesis that this initial peak is a transient. Eight subjects [4 obstructive sleep apnea (OSA), 4 controls] slept in an "iron lung" and wore a nasal mask connected to a continuous/bilevel positive airway pressure machine. Downstream pressure was measured using an epiglottic catheter. During non-rapid eye movement (NREM) sleep, subjects were hyperventilated to produce a central apnea, then extrathoracic pressure was decreased slowly (∼2-4 s) or abruptly (resistor model, the upper airway exhibits marked NED in some subjects.

  7. The role of feedback resistors and tid effects in the ASET response of a high speed current feedback amplifier

    International Nuclear Information System (INIS)

    Roig, F.; Dusseau, L.; Privat, A.; Vaille, J.R.; Boch, J.; Saigne, F.; Ribeiro, P.; Auriel, G.; Roche, N.J.H.; Marec, R.; Calvel, P.; Bezerra, F.; Ecoffet, R.; Azais, B.

    2014-01-01

    The influence of external circuit designs on ASET shapes in a high speed current feedback amplifier (CFA) (AD844) is investigated by means of the pulsed laser single event effect (PLSEE) simulation technique. Changes of the feedback resistors modify circuit's electrical parameters such as closed-loop gain and bandwidth, affecting amplifier stability and so ASET shapes. Qualitative explanations based on general electronic rules and feedback theories enable the understanding of a CFA operation establishing a correlation between the evolution of external feedback resistor values and ASET parameters. TID effects on the ASET sensitivity in AD844 CFA are also investigated in this work highlighting different behaviors according to the impacted bipolar transistor in the integrated circuit. (authors)

  8. Simulasi Dinamika untuk Menentukan Stabilitas Sistem Tenaga Listrik Menggunakan Thyristor Controlled Braking Resistor pada Sistem IEEE 34 Node Test Feeder

    Directory of Open Access Journals (Sweden)

    Andi Taufiq

    2012-09-01

    Full Text Available Terdapat berbagai macam metode untuk meningkatkan stabilitas sistem  tenaga listrik. Salah satunya adalah dengan menggunakan metode pengereman dinamis (dynamic braking. Generator sinkron sebagai distributed generator yang digerakkan oleh mesin diesel. Pada saat terjadi gangguan pada sistem, digunakan sebuah Thyristor Controlled Braking Resistor (TCBR untuk meredam osilasi yang terjadi. Sistem yang hendak dianalisis dinamika dan stabilitasnnya adalah IEEE 34 node test feeder. Dengan sistem ini diilustrasikan karakteristik dan keefektifan TCBR untuk meredam osilasi frekuensi rendah dan mencegah terjadinya ketidakstabilan transien sistem. Dari hasil analisis diperoleh bahwa dengan adanya penambahan TCBR (Thyristor Controlled Braking Resistor maka respon transien sistem akan menjadi lebih baik. Hal ini ditunjukkan dengan adanya penurunan overshoot dan settling timenya. Dengan demikian sistem akan menuju kondisi stabil dengan lebih cepat setelah terjadi gangguan.

  9. PROGRESSIVE MUSCLE RELAXATION INCREASE PEAK EXPIRATORY FLOW RATE ON CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS

    Directory of Open Access Journals (Sweden)

    Tintin Sukartini

    2017-07-01

    Full Text Available Introduction: Limited progressive air flow in Chronic Obstructive Pulmonary Disease (COPD can caused by small airway disease (bronchiolitis obstructive and loss of elasticity of the lung (emphysema. Further it can be decreasing the quality of life in COPD patients because dyspnea and uncomfortable in activity. Progressive muscle relaxation (PMR is one of the relaxation technique that can repair pulmonary ventilation by decreasing chronic constriction of the respiratory muscles. The objective of this study was to analyze the effect of progressive muscle relaxation on raised peak expiratory flow rate (PEFR. Method: A pre-experimental one group pre-post test design was used in this study. Population was all of the COPD patients at Pulmonary Specialist Polyclinic Dr Mohamad Soewandhie Surabaya. There were 8 respondents taken by using purposive sampling. PEFR was counted by using peak flow meter every six day. Data were analyzed by using Paired t-Test with significance level  p≤0.05. Result: The result showed that PMR had significance level on increasing of PEFR (p=0.012. Discussion: It can be concluded that PMR has an effect on raise PEFR. Further studies are recommended to measure the effect of PMR on respiratory rate (RR, heart rate (HR subjective dyspnoe symptoms, forced expiration volume on the first minute (FEV1 and mid maximum flow rate (MMFR in COPD patients.

  10. Peak expiratory flow rate (PEFR) among Nuclear Fuel Complex (NFC) employees

    International Nuclear Information System (INIS)

    Vijay Rao, J.; Venkaiah, K.; Mohan Rao, N.

    2010-01-01

    At Nuclear Fuel Complex (NFC), employees are exposed to ammonia, hydrofluoric acid, acetone, etc., which are respiratory toxicants and inhalation of these pollutants may produce irritation and obstruction in airways. Due to nature of their occupation, tradesman working in plants are having longer duration of exposure (LDE) and others, such as supervisors, scientific officers, helpers, etc., that occasionally visit plants are having shorter duration of exposure (SDE) to these pollutants. The peak expiratory flow rate (PEFR) is an index to diagnose obstruction in larger airways and this is metered with mini peak flow meter among 835 NFC employees. Using ANOVA test, PEFR value was compared according to age and smoking. The value was compared between LDE and SDE employees according to smoking and duration of employment. The multiple regression equation for prediction of PEFR was developed. Age, smokers and higher duration of LDE employees demonstrated significantly lower PEFR value. In comparison to 10 year duration, 30 and above year duration of employment, LDE employees showed a higher decline in PEFR, that is 95 L (17.6%) and in SDE employees, that is 41L (7.8%). This may be due to longer duration of employment of LD employees smoking prevention and follow up study is suggested. (author)

  11. Chest physiotherapy with positive expiratory pressure breathing after abdominal and thoracic surgery: a systematic review.

    Science.gov (United States)

    Orman, J; Westerdahl, E

    2010-03-01

    A variety of chest physiotherapy techniques are used following abdominal and thoracic surgery to prevent or reduce post-operative complications. Breathing techniques with a positive expiratory pressure (PEP) are used to increase airway pressure and improve pulmonary function. No systematic review of the effects of PEP in surgery patients has been performed previously. The purpose of this systematic review was to determine the effect of PEP breathing after an open upper abdominal or thoracic surgery. A literature search of randomised-controlled trials (RCT) was performed in five databases. The trials included were systematically reviewed by two independent observers and critically assessed for methodological quality. We selected six RCT evaluating the PEP technique performed with a mechanical device in spontaneously breathing adult patients after abdominal or thoracic surgery via thoracotomy. The methodological quality score varied between 4 and 6 on the Physiotherapy Evidence Database score. The studies were published between 1979 and 1993. Only one of the included trials showed any positive effects of PEP compared to other breathing techniques. Today, there is scarce scientific evidence that PEP treatment is better than other physiotherapy breathing techniques in patients undergoing abdominal or thoracic surgery. There is a lack of studies investigating the effect of PEP over placebo or no physiotherapy treatment.

  12. First characterization of the expiratory flow increase technique: method development and results analysis

    International Nuclear Information System (INIS)

    Maréchal, L; Barthod, C; Jeulin, J C

    2009-01-01

    This study provides an important contribution to the definition of the expiratory flow increase technique (EFIT). So far, no measuring means were suited to assess the manual EFIT performed on infants. The proposed method aims at objectively defining the EFIT based on the quantification of pertinent cognitive parameters used by physiotherapists when practicing. We designed and realized customized instrumented gloves endowed with pressure and displacement sensors, and the associated electronics and software. This new system is specific to the manoeuvre, to the user and innocuous for the patient. Data were collected and analysed on infants with bronchiolitis managed by an expert physiotherapist. The analysis presented is realized on a group of seven subjects (mean age: 6.1 months, SD: 1.1; mean chest circumference: 44.8 cm, SD: 1.9). The results are consistent with the physiotherapist's tactility. In spite of inevitable variability due to measurements on infants, repeatable quantitative data could be reported regarding the manoeuvre characteristics: the magnitudes of displacements do not exceed 10 mm on both hands; the movement of the thoracic hand is more vertical than the movement of the abdominal hand; the maximum applied pressure with the thoracic hand is about twice higher than with the abdominal hand; the thrust of the manual compression lasts (590 ± 62) ms. Inter-operators measurements are in progress in order to generalize these results

  13. Peak expiratory flow as a predictor for the effectiveness of sport for patients with COPD.

    Science.gov (United States)

    Jungblut, S; Frickmann, H; Klingler, J; Zimmermann, B; Bargon, Joachim

    2006-01-31

    This study intended to find simple parameters that were able to determine the increase in physical performance as a result of sport in a group of patients with COPD (lung sport). We regularly investigated pulse, oxygenation and peak expiratory flow in participants with COPD of a "lung sport group", who participated in a structured weekly training program under professional supervision. Ten volunteers (7 females, 3 males, median of age = 69) with COPD (grade II-III) took part in the study. - The relative changes after 3 and 6 months were compared with the values of the first month of exercise. Measurements were carried out before exercise, after stamina training and at the end of the program. - Pulse and oxygenation did not show any changes. However, there was a significant improvement of peak flow after 6 months. - These peak flow changes represent further evidence of positive effects of sport in COPD and provide a parameter which allows the patients themselves to measure and evaluate the success of their physical activity.

  14. Prediction of Spirometric Forced Expiratory Volume (FEV1) Data Using Support Vector Regression

    Science.gov (United States)

    Kavitha, A.; Sujatha, C. M.; Ramakrishnan, S.

    2010-01-01

    In this work, prediction of forced expiratory volume in 1 second (FEV1) in pulmonary function test is carried out using the spirometer and support vector regression analysis. Pulmonary function data are measured with flow volume spirometer from volunteers (N=175) using a standard data acquisition protocol. The acquired data are then used to predict FEV1. Support vector machines with polynomial kernel function with four different orders were employed to predict the values of FEV1. The performance is evaluated by computing the average prediction accuracy for normal and abnormal cases. Results show that support vector machines are capable of predicting FEV1 in both normal and abnormal cases and the average prediction accuracy for normal subjects was higher than that of abnormal subjects. Accuracy in prediction was found to be high for a regularization constant of C=10. Since FEV1 is the most significant parameter in the analysis of spirometric data, it appears that this method of assessment is useful in diagnosing the pulmonary abnormalities with incomplete data and data with poor recording.

  15. Breath-by-breath analysis of expiratory gas concentration in chickens.

    Science.gov (United States)

    Itabisashi, T

    1981-01-01

    Expiratory oxygen and carbon-dioxide concentration were analysed breath by breath in order to examine their wave forms in adult awake hens restrained in various postural positions, including supine, prone and sitting positions. Expired gas was collected at the nostril in almost all the hens. In the sitting position free from vocalization, feeding, drinking, panting, and restlessness, hens showed various forms of stable pattern of oxygen-gas curves. These forms were classified into three types, or the ascending, flat and descending types, with respect to the plateau inclination. The waves of carbon-dioxide were not always a mirror image of those of oxygen. The rate of occurrence of each type varied with the hen's postural position. The wave form was altered with the experimental body-rotation of the hen. When placed between the deflections of stable pattern, the episodes of wave deformation resembling that seen at the time of uneven pulmonary ventilation in mammals could frequently be observed in any hen's posture examined. Cardiogenic oscillation appeared on the plateau of expired-gas curves.

  16. The effects of smokeless cookstoves on peak expiratory flow rates in rural Honduras.

    Science.gov (United States)

    Rennert, W P; Porras Blanco, R M; Muniz, G B

    2015-09-01

    The use of biomass fuel for cooking in traditional cookstove designs negatively affects respiratory health of communities in developing countries. Indoor pollution affects particularly women and children, who are participating in food preparation. The effects of smokeless cookstove designs on indoor pollution are well documented, but few studies exist to assess the effects of improved stove designs on the respiratory health of community members. This study uses peak expiratory flow rate (PEFR) measurements in a before-and-after format to assess respiratory function of inhabitants of all 30 houses of Buenas Noches in central Honduras. PEFRs are measured before and 6 months after the installation of Justa stoves in people's homes. Health behaviors, respiratory symptoms and fire wood use are evaluated in a door-to-door survey format. A total of 137 eligible women and children between 6 and 14 years participated in the study. PEFR improved by 9.9-18.5% (P < 0.001) depending on the participants' exposure to indoor pollution. Health complaints like cough and behaviors like clinic visits did not change with the introduction of smokeless cookstove technology. Smokeless stoves improve respiratory health in an environment of high levels of indoor pollution. © The Author 2014. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. The longitudinal relationship of work stress with peak expiratory flow: a cohort study.

    Science.gov (United States)

    Loerbroks, Adrian; Karrasch, Stefan; Lunau, Thorsten

    2017-10-01

    Research has suggested that psychological stress is associated with reduced lung function and with the development of respiratory disease. Among the major potential sources of stress in adulthood are working conditions. We aimed to examine the relationship of work stress with lung function. We drew on 4-year prospective data from the Survey of Health, Ageing and Retirement in Europe. The analyzed sample comprised 2627 workers aged 50 years or older who were anamnestically free of respiratory disease. Work stress at baseline was operationalized by abbreviated instruments measuring the well-established effort-reward imbalance model (seven items) and the control component of the job-demand control (two items). Peak expiratory flow (PEF) was determined at baseline and at follow-up. Continuous and categorized (i.e., by the tertile) work stress variables were employed in multivariable linear regression models to predict PEF change. Work stress did not show statistically significant associations with PEF change. For instance, the unstandardized regression coefficient for PEF decline according to high versus low effort-reward imbalance was -1.41 (95% confidence interval = -3.75, 0.94). Our study is the first to examine prospective relationships between work stress and PEF. Overall, we did not observe meaningful associations. Future studies should consider a broader spectrum of spirometric parameters and should expand research to younger and possibly less-selected working populations (i.e., aged <50 years).

  18. Expiratory flow limitation and operating lung volumes during exercise in older and younger adults.

    Science.gov (United States)

    Smith, Joshua R; Kurti, Stephanie P; Meskimen, Kayla; Harms, Craig A

    2017-06-01

    We determined the effect of aging on expiratory flow limitation (EFL) and operating lung volumes when matched for lung size. We hypothesized that older adults will exhibit greater EFL and increases in EELV during exercise compared to younger controls. Ten older (5M/5W; >60years old) and nineteen height-matched young adults (10M/9W) were recruited. Young adults were matched for%predicted forced vital capacity (FVC) (Y-matched%Pred FVC; n=10) and absolute FVC (Y-matched FVC; n=10). Tidal flow-volume loops were recorded during the incremental exercise test with maximal flow-volume loops measured pre- and post-exercise. Compared to younger controls, older adults exhibited more EFL at ventilations of 26, 35, 51, and 80L/min. The older group had higher end-inspiratory lung volume compared to Y-matched%Pred FVC group during submaximal ventilations. The older group increased EELV during exercise, while EELV stayed below resting in the Y-matched%Pred FVC group. These data suggest older adults exhibit more EFL and increase EELV earlier during exercise compared to younger adults. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Can Preoperative Peak Expiratory Flow Predict Postoperative Pulmonary Complications in Lung Cancer Patients Undergoing Lobectomy?

    Directory of Open Access Journals (Sweden)

    Kun ZHOU

    2017-09-01

    Full Text Available Background and objective Postoperative pulmonary complications (PPCs, especially postoperative pneumonia (POP, directly affect the rapid recovery of lung cancer patients after surgery. Peak expiratory flow (PEF can reflect airway patency and cough efficiency. Moreover, cough impairment may lead to accumulation of pulmonary secretions which can increase the risk of PPCs. The aim of this study is to investigate the effect of preoperative PEF on PPCs in patients with lung cancer. Methods Retrospective research was conducted on 433 lung cancer patients who underwent lobectomy at the West China Hospital of Sichuan University from January 2014 to December 2015. The associations between preoperative PEF and PPCs were analyzed based on patients’ basic characteristics and clinical data in hospital. Results Preoperative PEF value in PPCs group (280.93±88.99 L/min was significantly lower than that in non-PPCs group (358.38±93.69 L/min (P320 L/min group (9.4%(P<0.001. Conclusion Preoperative PEF and PPCs are correlated, and PEF may be used as a predictor of PPCs.

  20. A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India

    Directory of Open Access Journals (Sweden)

    Jenny Jayapal

    2014-01-01

    Full Text Available Background: Peak Expiratory Flow Rate (PEFR reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows hour to hour variation that follows a specific pattern in asthmatics and healthy individuals. Adequate data is not available for the diurnal variation in normal individuals who are students in professional courses and had a sedentary life style. Hence, this study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. Materials and Methods: Peak expiratory flow rate was recorded in 50 adult healthy female students aged 18-23 years and studying in professional courses. Mini Wright′s peak flow meter was used to measure the peak expiratory flow rate. PEFR were recorded at 7-8 a.m., 10-11 a.m., 1-2 p.m., 4-5 p.m., and 7-8 p.m. for two consecutive days. Results: On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in the morning at 7-8 h PEFR, which increased in the daytime, peaking in the afternoon at 1-2 p.m. and eventually decreased in the night. Subjects did not show the peak PEFR values at the same time point, 10% of subjects had a rise in PEFR in the early morning, afternoon (1-2 p.m. peak was observed in 48% subjects and evening (4-5 p.m. peak was observed in 16% subjects. 14% subjects showed a peak in the night time (7-8 p.m. PEFR values. Conclusion: This study provided the preliminary reference data of diurnal variation of peak expiratory flow rate in healthy adults. Since, there is a variation in the peak expiratory flow rate recorded during different time points of the day; hence, to compare the PEFR between individuals it is advisable to record the PEFR at the same time point.

  1. Microstructure development in RuO2-glass thick-film resistors and its effect on the electrical resistivity

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Iizuka, K.

    1990-01-01

    Microstructure development in RuO 2 -glass thick-film resistors has been studied by optical microscopy with special emphasis on the effect of glass particle size and mixing and firing conditions. The microstructure development has been characterized by the coalescence of glass grains, infiltration of glass into RuO 2 particle aggregates, and agglomeration of RuO 2 particles. The resistivity-firing temperature relationship has been correlated with the microstructure development

  2. DVCCs Based High Input Impedance Voltage-Mode First-Order Filters Employing Grounded Capacitor and Resistor

    Directory of Open Access Journals (Sweden)

    J. W. Horng

    2010-12-01

    Full Text Available A voltage-mode high input impedance first-order highpass, lowpass and allpass filters using two differential voltage current conveyors (DVCCs, one grounded capacitor and one grounded resistor is presented. The highpass, lowpass and allpass signals can be obtained simultaneously from the circuit configuration. The suggested filter uses a canonical number of passive components without requiring any component matching condition. The simulation results confirm the theoretical analysis.

  3. Nanoelectronics «bottom – up»: current generation, generalized Ohm’s law, elastic resistors, conductivity modes, thermoelectricity

    Directory of Open Access Journals (Sweden)

    Юрій Олексійович Кругляк

    2015-07-01

    Full Text Available General questions of electronic conductivity, current generation with the use of electrochemical potentials and Fermi functions, elastic resistor model, ballistic and diffusion transport, conductivity modes, n- and p-conductors and graphene, formulation of the generalized Ohm’s law, thermoelectric phenomena of Seebeck and Peltier, quality indicators and thermoelectric optimization, ballistic and diffusive phonon heat current are discussed in the frame of the «bottom – up» approach of modern nanoelectronics

  4. Characteristics research of pressure sensor based on nanopolysilicon thin films resistors

    Science.gov (United States)

    Zhao, Xiaofeng; Li, Dandan; Wen, Dianzhong

    2017-10-01

    To further improve the sensitivity temperature characteristics of pressure sensor, a kind of pressure sensor taking nanopolysilicon thin films as piezoresistors is proposed in this paper. On the basis of the microstructure analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) tests, the preparing process of nanopolysilicon thin films is optimized. The effects of film thickness and annealing temperature on the micro-structure of nanopolysilicon thin films were studied, respectively. In order to realize the measurement of external pressure, four nanopolysilicon thin films resistors were arranged at the edges of square silicon diaphragm connected to a Wheatstone bridge, and the chip of the sensor was designed and fabricated on a 〈100〉 orientation silicon wafer by microelectromechanical system (MEMS) technology. Experimental result shows that when I = 6.80 mA, the sensitivity of the sensor PS-1 is 0.308 mV/kPa, and the temperature coefficient of sensitivity (TCS) is about -1742 ppm/∘C in the range of -40-140∘C. It is possible to obviously improve the sensitivity temperature characteristics of pressure sensor by the proposed sensors.

  5. Accurate calibration of resistance ratios between 1 MΩ and 1 GΩ using series resistors

    International Nuclear Information System (INIS)

    Yu, Kwang Min; Ihm, G

    2011-01-01

    As shown in high-resistance key comparisons carried out by the Consultative Committee for Electricity and Magnetism (CCEM), Inter-American Metrology System (SIM) and European Association of National Metrology Institutes (EURAMET), the accuracy of 10 MΩ and 1 GΩ resistances depends on ratio values between the reference resistance and unknown resistance and the accuracy of the reference resistance, which is determined with a quantized Hall resistance standard. This paper presents a method for calibrating 10:1 ratios in a high-resistance bridge using series resistors simply and accurately. By applying the 10:1 ratio errors determined using the presented method, the combined relative standard uncertainty for 1 GΩ resistance measurements using a modified Wheatstone bridge was estimated to be on the 1 × 10 −6 level. The method was also applied to 1 GΩ resistance measurements using a direct-current comparator resistance bridge. It was found that the 1 GΩ resistances determined by the two bridges agreed within 2.4 × 10 −6 Ω/Ω. We expect that the presented method can also be used to calibrate arbitrary resistance ratios

  6. Force Sensing Resistor and Evaluation of Technology for Wearable Body Pressure Sensing

    Directory of Open Access Journals (Sweden)

    Davide Giovanelli

    2016-01-01

    Full Text Available Wearable technologies are gaining momentum and widespread diffusion. Thanks to devices such as activity trackers, in form of bracelets, watches, or anklets, the end-users are becoming more and more aware of their daily activity routine, posture, and training and can modify their motor-behavior. Activity trackers are prevalently based on inertial sensors such as accelerometers and gyroscopes. Loads we bear with us and the interface pressure they put on our body also affect posture. A contact interface pressure sensing wearable would be beneficial to complement inertial activity trackers. What is precluding force sensing resistors (FSR to be the next best seller wearable? In this paper, we provide elements to answer this question. We build an FSR based on resistive material (Velostat and printed conductive ink electrodes on polyethylene terephthalate (PET substrate; we test its response to pressure in the range 0–2.7 kPa. We present a state-of-the-art review, filtered by the need to identify technologies adequate for wearables. We conclude that the repeatability is the major issue yet unsolved.

  7. Detection and quantification through a lipid membrane using the molecularly controlled semiconductor resistor.

    Science.gov (United States)

    Bavli, Danny; Tkachev, Maria; Piwonski, Hubert; Capua, Eyal; de Albuquerque, Ian; Bensimon, David; Haran, Gilad; Naaman, Ron

    2012-01-10

    The detection of covalent and noncovalent binding events between molecules and biomembranes is a fundamental goal of contemporary biochemistry and analytical chemistry. Currently, such studies are performed routinely using fluorescence methods, surface-plasmon resonance spectroscopy, and electrochemical methods. However, there is still a need for novel sensitive miniaturizable detection methods where the sample does not have to be transferred to the sensor, but the sensor can be brought into contact with the sample studied. We present a novel approach for detection and quantification of processes occurring on the surface of a lipid bilayer membrane, by monitoring the current change through the n-type GaAs-based molecularly controlled semiconductor resistor (MOCSER), on which the membrane is adsorbed. Since GaAs is susceptible to etching in an aqueous environment, a protective thin film of methoxysilane was deposited on the device. The system was found to be sensitive enough to allow monitoring changes in pH and in the concentration of amino acids in aqueous solution on top of the membrane. When biotinylated lipids were incorporated into the membrane, it was possible to monitor the binding of streptavidin or avidin. The device modified with biotin-streptavidin complex was capable of detecting the binding of streptavidin antibodies to immobilized streptavidin with high sensitivity and selectivity. The response depends on the charge on the analyte. These results open the way to facile electrical detection of protein-membrane interactions.

  8. Carbon film resistor electrode for amperometric determination of acetaminophen in pharmaceutical formulations.

    Science.gov (United States)

    Felix, Fabiana S; Brett, Christopher M A; Angnes, Lúcio

    2007-04-11

    Flow injection analysis (FIA) with amperometric detection was employed for acetaminophen quantification in pharmaceutical formulations using a carbon film resistor electrode. This sensor exhibited sharp and reproducible current peaks for acetaminophen without chemical modification of its surface. A wide linear working range (8.0x10(-7) to 5.0x10(-4) mol L(-1)) in phosphate buffer solution as well as high sensitivity (0.143 A mol(-1) L cm(-2)) and low submicromolar detection limit (1.36x10(-7) mol L(-1)) were achieved. The repeatability (R.S.D. for 10 successive injections of 5.0x10(-6) and 5.0x10(-5) mol L(-1) acetaminophen solutions) was 3.1 and 1.3%, respectively, without any memory effect between injections. The new procedure was applied to the analyses of commercial pharmaceutical products and the results were in good agreement with those obtained utilizing a spectrophotometric method. Consequently, this amperometric method has been shown to be very suitable for quality control analyses and other applications with similar requirements.

  9. Resistor mesh model of a spherical head: part 1: applications to scalp potential interpolation.

    Science.gov (United States)

    Chauveau, N; Morucci, J P; Franceries, X; Celsis, P; Rigaud, B

    2005-11-01

    A resistor mesh model (RMM) has been implemented to describe the electrical properties of the head and the configuration of the intracerebral current sources by simulation of forward and inverse problems in electroencephalogram/event related potential (EEG/ERP) studies. For this study, the RMM representing the three basic tissues of the human head (brain, skull and scalp) was superimposed on a spherical volume mimicking the head volume: it included 43 102 resistances and 14 123 nodes. The validation was performed with reference to the analytical model by consideration of a set of four dipoles close to the cortex. Using the RMM and the chosen dipoles, four distinct families of interpolation technique (nearest neighbour, polynomial, splines and lead fields) were tested and compared so that the scalp potentials could be recovered from the electrode potentials. The 3D spline interpolation and the inverse forward technique (IFT) gave the best results. The IFT is very easy to use when the lead-field matrix between scalp electrodes and cortex nodes has been calculated. By simple application of the Moore-Penrose pseudo inverse matrix to the electrode cap potentials, a set of current sources on the cortex is obtained. Then, the forward problem using these cortex sources renders all the scalp potentials.

  10. The effect of biomechanical variables on force sensitive resistor error: Implications for calibration and improved accuracy.

    Science.gov (United States)

    Schofield, Jonathon S; Evans, Katherine R; Hebert, Jacqueline S; Marasco, Paul D; Carey, Jason P

    2016-03-21

    Force Sensitive Resistors (FSRs) are commercially available thin film polymer sensors commonly employed in a multitude of biomechanical measurement environments. Reasons for such wide spread usage lie in the versatility, small profile, and low cost of these sensors. Yet FSRs have limitations. It is commonly accepted that temperature, curvature and biological tissue compliance may impact sensor conductance and resulting force readings. The effect of these variables and degree to which they interact has yet to be comprehensively investigated and quantified. This work systematically assesses varying levels of temperature, sensor curvature and surface compliance using a full factorial design-of-experiments approach. Three models of Interlink FSRs were evaluated. Calibration equations under 12 unique combinations of temperature, curvature and compliance were determined for each sensor. Root mean squared error, mean absolute error, and maximum error were quantified as measures of the impact these thermo/mechanical factors have on sensor performance. It was found that all three variables have the potential to affect FSR calibration curves. The FSR model and corresponding sensor geometry are sensitive to these three mechanical factors at varying levels. Experimental results suggest that reducing sensor error requires calibration of each sensor in an environment as close to its intended use as possible and if multiple FSRs are used in a system, they must be calibrated independently. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Functional characteristics of a new electrolarynx "Evada" having a force sensing resistor sensor.

    Science.gov (United States)

    Choi, H S; Park, Y J; Lee, S M; Kim, K M

    2001-12-01

    Electrolarynxes have been used as one of the rehabilitation methods for laryngectomees. Earlier electrolarynxes could not alter frequency and intensity simultaneously during conversation. Recently, we developed an electrolarynx named "Evada" (prototype so far) using a force sensing resistor (FSR) sensor that can control both frequency and intensity simultaneously during conversation. Employing three types of electrolarynxes (Evada, Servox-inton, Nu-vois), this study was undertaken to examine the functional characteristics of Evada for the normal control group and for laryngectomess. Five laryngectomees and five normal adults were asked to express three sentences (declarative sentence, "You stay here.", interrogative sentence, "You stay here?", and imperative sentence, "You! Stay here.") using three types of electrolarynxes. Frequency and intensity changes between the first and last vowels in the three sentences were calculated and analyzed statistically by paired t test. The frequency changes in the interrogative and imperative sentences were more prominent in Evada than in Servox-inton and Nu-vois. The intensity changes in the interrogative and imperative sentences were also more prominent in Evada than in Servox-inton and Nu-vois. Evada controls frequency and/or intensity by having the subject press the control button(s). Therefore, Evada appears to be better at producing intonation and contrastive stress than Nu-vois and Servox-inton.

  12. Doped nanocrystalline ZnO powders for non-linear resistor applications by spray pyrolysis method.

    Science.gov (United States)

    Hembram, Kaliyan; Vijay, R; Rao, Y S; Rao, T N

    2009-07-01

    Homogeneous and doped nanocrystalline ZnO powders (30-200 nm) were synthesized by spray pyrolysis technique. The spray pyrolysed powders were calcined in the temperature range of 500-750 degrees C. Formation of insulating pyrochlore phase started from 700 degrees C during the calcination itself. The calcined powders were compacted and sintered at different temperatures ranging from 900-1200 degrees C for 0.5-4 h. The densification behavior was found to be dependent on calcination temperature of the nanopowder. The resulting discs were found to have density (5.34-5.62 g/cc) in the range of 96-99% of theoretical density. The breakdown voltage value obtained for the nanopowder based non-linear resistor is 10.3 kV/cm with low leakage current density of 0.7 microA/cm2 and coefficient of nonlinearity as high as 193. The activation energy for grain growth of the doped ZnO nanopowder powders is 449.4 +/- 15 kJ/mol.

  13. Combined TiN- and TaN temperature compensated thin film resistors

    International Nuclear Information System (INIS)

    Malmros, Anna; Andersson, Kristoffer; Rorsman, Niklas

    2012-01-01

    The opposite signs of the temperature coefficient of resistance (TCR) of two thin film materials, titanium nitride (TiN) and tantalum nitride (TaN), were used to form temperature compensated thin film resistors (TFRs). The principle of designing temperature compensated TFRs by connecting TFRs of each compound in series or in parallel was demonstrated. TiN, TaN, and combined TiN and TaN TFRs for monolithic microwave integrated circuits (MMICs) were fabricated by reactive sputtering. DC characterization was performed over the temperature range of 30–200 °C. The TiN TFRs exhibited an increase in resistivity with temperature with TCRs of 540 and 750 ppm/°C. The TaN TFR on the other hand exhibited a negative TCR of − 470 ppm/°C. The shunted TFRs were fabricated by serial deposition of TiN and TaN to form a bilayer component. The TCRs of the series- and shunt configurations were experimentally reduced to − 60 and 100 ppm/°C, respectively. The concept of temperature compensation was used to build a Wheatstone bridge with an application in on-chip temperature sensing.

  14. Three-dimensional random resistor-network model for solid oxide fuel cell composite electrodes

    International Nuclear Information System (INIS)

    Abbaspour, Ali; Luo Jingli; Nandakumar, K.

    2010-01-01

    A three-dimensional reconstruction of solid oxide fuel cell (SOFC) composite electrodes was developed to evaluate the performance and further investigate the effect of microstructure on the performance of SOFC electrodes. Porosity of the electrode is controlled by adding pore former particles (spheres) to the electrode and ignoring them in analysis step. To enhance connectivity between particles and increase the length of triple-phase boundary (TPB), sintering process is mimicked by enlarging particles to certain degree after settling them inside the packing. Geometrical characteristics such as length of TBP and active contact area as well as porosity can easily be calculated using the current model. Electrochemical process is simulated using resistor-network model and complete Butler-Volmer equation is used to deal with charge transfer process on TBP. The model shows that TPBs are not uniformly distributed across the electrode and location of TPBs as well as amount of electrochemical reaction is not uniform. Effects of electrode thickness, particle size ratio, electron and ion conductor conductivities and rate of electrochemical reaction on overall electrochemical performance of electrode are investigated.

  15. Circular resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V

    2010-01-01

    We introduce an algorithm for the numerical solution of electrical impedance tomography (EIT) in two dimensions, with partial boundary measurements. The algorithm is an extension of the one in Borcea et al (2008 Inverse Problems 24 035013 (31pp)) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) for EIT with full boundary measurements. It is based on resistor networks that arise in finite volume discretizations of the elliptic partial differential equation for the potential on so-called optimal grids that are computed as part of the problem. The grids are adaptively refined near the boundary, where we measure and expect better resolution of the images. They can be used very efficiently in inversion, by defining a reconstruction mapping that is an approximate inverse of the forward map, and acts therefore as a preconditioner in any iterative scheme that solves the inverse problem via optimization. The main result in this paper is the construction of optimal grids for EIT with partial measurements by extremal quasiconformal (Teichmüller) transformations of the optimal grids for EIT with full boundary measurements. We present the algorithm for computing the reconstruction mapping on such grids, and we illustrate its performance with numerical simulations. The results show an interesting trade-off between the resolution of the reconstruction in the domain of the solution and distortions due to artificial anisotropy induced by the distribution of the measurement points on the accessible boundary

  16. An evaluation of a translator for finite element data to resistor/capacitor data for the heat diffusion equation

    International Nuclear Information System (INIS)

    Manteufel, R.D.; Klein, D.E.; Yoshimura, H.R.

    1988-01-01

    This paper evaluates a translator for finite element data to resistor/capacitor data (FEM/RC) for the numerical solution of heat diffusion problems. The translator involves the derivation of thermal resistors and capacitors, implicit in the heat balance formulation of the finite difference method. It uses a finite element mesh, which consists of nodes and elements and is implicit in the Galerkin finite element method (GFEM). This hybrid translation method, FEM/RC, has been incorporated in Q/TRAN, a new thermal analysis computer code. This evaluation compares Q/TRAN, HEATING-6, and a research code employing GFEM on a purely mathematical, highly nonlinear steady-state conduction benchmark problem. The evaluation concludes that the FEM/RC technique has numerical characteristics that are consistent with comparable schemes for the benchmark problem. FEM/RC also accurately translates skewed meshes. Because FEM/RC generates resistors and capacitors, it appears to offer a more efficient method than the classical GFEM

  17. Asymptotic expansion for the resistance between two maximally separated nodes on an M by N resistor network.

    Science.gov (United States)

    Izmailian, N Sh; Huang, Ming-Chang

    2010-07-01

    We analyze the exact formulas for the resistance between two arbitrary notes in a rectangular network of resistors under free, periodic and cylindrical boundary conditions obtained by Wu [J. Phys. A 37, 6653 (2004)]. Based on such expression, we then apply the algorithm of Ivashkevich, Izmailian, and Hu [J. Phys. A 35, 5543 (2002)] to derive the exact asymptotic expansions of the resistance between two maximally separated nodes on an M×N rectangular network of resistors with resistors r and s in the two spatial directions. Our results is 1/s (R(M×N))(r,s) = c(ρ)ln S + c(0)(ρ,ξ) + ∑(p=1)(∞) (c(2p)(ρ,ξ))/S(p) with S = MN, ρ = r/s and ξ = M/N. The all coefficients in this expansion are expressed through analytical functions. We have introduced the effective aspect ratio ξeff = square root(ρ)ξ for free and periodic boundary conditions and ξeff = square root(ρ)ξ/2 for cylindrical boundary condition and show that all finite-size correction terms are invariant under transformation ξeff→1/ξeff.

  18. Development of high voltage surge limiting resistor for protection of HV multiplier of 3 MeV DC accelerator

    International Nuclear Information System (INIS)

    Dewangan, S.; Sharma, D.K.; Bakhtsingh, R.I.

    2013-01-01

    A 3MeV, 10mA DC electron beam accelerator is in commissioning stages at EBC, Kharghar, Navi Mumbai. The accelerating potential of -3MV is generated by a Parallel Coupled Voltage Multiplier (PCVM) scheme using 74 stages of HV rectifier stacks in the 6 kg/cm 2 SF6 gas environment. The HV surges of order of 600kV, 42kA, 10ns is estimated across the rectifier stacks during sparking in the multiplier column. To limit the surge current and protect the rectifier diodes, a non inductive thick film surge limiting resistor (SLR) and protective spark gap is designed and developed. The rectifier stacks with surge limiting resistors at both the ends and protective spark gap in parallel has been successfully tested in simulated surge condition at an impulse voltage of 212kVp, 150ns FWHM and surge energy of 200J, 10ms, 20kV at 6kg/cm 2 SF6 gas environment and found satisfactorily. Subsequently the HV multiplier was installed with this surge protection scheme and is being tested at 1.2 MeV level. This paper describes the design features and test results of the non-inductive surge limiting resistor. (author)

  19. Effects of a parallel resistor on electrical characteristics of a piezoelectric transformer in open-circuit transient state.

    Science.gov (United States)

    Chang, Kuo-Tsai

    2007-01-01

    This paper investigates electrical transient characteristics of a Rosen-type piezoelectric transformer (PT), including maximum voltages, time constants, energy losses and average powers, and their improvements immediately after turning OFF. A parallel resistor connected to both input terminals of the PT is needed to improve the transient characteristics. An equivalent circuit for the PT is first given. Then, an open-circuit voltage, involving a direct current (DC) component and an alternating current (AC) component, and its related energy losses are derived from the equivalent circuit with initial conditions. Moreover, an AC power control system, including a DC-to-AC resonant inverter, a control switch and electronic instruments, is constructed to determine the electrical characteristics of the OFF transient state. Furthermore, the effects of the parallel resistor on the transient characteristics at different parallel resistances are measured. The advantages of adding the parallel resistor also are discussed. From the measured results, the DC time constant is greatly decreased from 9 to 0.04 ms by a 10 k(omega) parallel resistance under open output.

  20. Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease.

    Science.gov (United States)

    Finucane, Kevin E; Singh, Bhajan

    2018-01-01

    Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇ exp ), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇ exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV 1 ) 53% predicted. Lung volumes (Vl), V̇ exp , esophageal pressure (Pes), Ti, and end-tidal Pco 2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇ exp and V̇ with submaximal forced vital capacities breathing air (V̇ sFVC ) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇ exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇ (0.3Vt) and Pes (0.3Vt) , respectively], Ti, and Rl correlated with [Formula: see text] ( P pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.

  1. Volume-monitored chest CT: a simplified method for obtaining motion-free images near full inspiratory and end expiratory lung volumes

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Kathryn S. [The Ohio State University College of Medicine, Columbus, OH (United States); Long, Frederick R. [Nationwide Children' s Hospital, The Children' s Radiological Institute, Columbus, OH (United States); Flucke, Robert L. [Nationwide Children' s Hospital, Department of Pulmonary Medicine, Columbus, OH (United States); Castile, Robert G. [The Research Institute at Nationwide Children' s Hospital, Center for Perinatal Research, Columbus, OH (United States)

    2010-10-15

    Lung inflation and respiratory motion during chest CT affect diagnostic accuracy and reproducibility. To describe a simple volume-monitored (VM) method for performing reproducible, motion-free full inspiratory and end expiratory chest CT examinations in children. Fifty-two children with cystic fibrosis (mean age 8.8 {+-} 2.2 years) underwent pulmonary function tests and inspiratory and expiratory VM-CT scans (1.25-mm slices, 80-120 kVp, 16-40 mAs) according to an IRB-approved protocol. The VM-CT technique utilizes instruction from a respiratory therapist, a portable spirometer and real-time documentation of lung volume on a computer. CT image quality was evaluated for achievement of targeted lung-volume levels and for respiratory motion. Children achieved 95% of vital capacity during full inspiratory imaging. For end expiratory scans, 92% were at or below the child's end expiratory level. Two expiratory exams were judged to be at suboptimal volumes. Two inspiratory (4%) and three expiratory (6%) exams showed respiratory motion. Overall, 94% of scans were performed at optimal volumes without respiratory motion. The VM-CT technique is a simple, feasible method in children as young as 4 years to achieve reproducible high-quality full inspiratory and end expiratory lung CT images. (orig.)

  2. Double profunda brachii artery

    Directory of Open Access Journals (Sweden)

    Gavishiddappa A Hadimani

    2016-01-01

    Full Text Available Brachial artery (BA is a continuation of the axillary artery at the lower border of teres major. In the cubital fossa, BA divides into radial artery and ulnar artery as terminal branches. Large branch given from the BA in the upper part is profunda brachii artery. In the present case, we noticed double profunda brachii that arises from the BA. They are profunda brachii artery 1 and profunda brachii artery 2. Profunda brachii artery 1 arises in the proximal part of the BA and profunda brachii artery 2 arises distal to the profunda brachii artery 1. Both the arteries run inferolaterally in the spiral groove along with radial nerve. Variations of profunda brachii artery are important during harvesting of the lateral arm flaps and may lead to inadvertent injury during percutaneous arterial catheterization or injection of drugs.

  3. Acute arterial occlusion - kidney

    Science.gov (United States)

    ... main artery to the kidney is called the renal artery. Reduced blood flow through the renal artery can hurt kidney function. ... need include: Duplex Doppler ultrasound exam of the renal arteries to test blood flow MRI of the kidney arteries, which can show ...

  4. The respiratory drive to thoracic motoneurones in the cat and its relation to the connections from expiratory bulbospinal neurones

    DEFF Research Database (Denmark)

    Saywell, S A; Anissimova, N P; Ford, T W

    2007-01-01

    of connection revealed were related to the presence and size of central respiratory drive potentials in the same motoneurones. Intracellular recordings were made from motoneurones in segments T5-T9 of the spinal cord of anaesthetized cats. Spike-triggered averaging from expiratory bulbospinal neurones...... in the caudal medulla revealed monosynaptic EPSPs in all groups of motoneurones, with the strongest connections to expiratory motoneurones with axons in the internal intercostal nerve. In the latter, connection strength was similar irrespective of the target muscle (e.g. external abdominal oblique or internal...... intercostal) and the EPSP amplitude was positively correlated with the amplitude of the central respiratory drive potential of the motoneurone. For this group, EPSPs were found in 45/83 bulbospinal neurone/motoneurone pairs, with a mean amplitude of 40.5 microV. The overall strength of the connection supports...

  5. Relationship between pre-extubation positive endexpiratory pressure and oxygenation after coronary artery bypass grafting

    Directory of Open Access Journals (Sweden)

    Reijane Oliveira Lima

    2015-08-01

    Full Text Available Abstract Introduction After removal of endotracheal tube and artificial ventilation, ventilatory support should be continued, offering oxygen supply to ensure an arterial oxygen saturation close to physiological. Objective: The aim of this study was to investigate the effects of positive-end expiratory pressure before extubation on the oxygenation indices of patients undergoing coronary artery bypass grafting. Methods: A randomized clinical trial with seventy-eight patients undergoing coronary artery bypass grafting divided into three groups and ventilated with different positive-end expiratory pressure levels prior to extubation: Group A, 5 cmH2O (n=32; Group B, 8 cmH2O (n=26; and Group C, 10 cmH2O (n=20. Oxygenation index data were obtained from arterial blood gas samples collected at 1, 3, and 6 h after extubation. Patients with chronic pulmonary disease and those who underwent off-pump, emergency, or combined surgeries were excluded. For statistical analysis, we used Shapiro-Wilk, G, Kruskal-Wallis, and analysis of variance tests and set the level of significance at P<0.05. Results Groups were homogenous with regard to demographic, clinical, and surgical variables. There were no statistically significant differences between groups in the first 6 h after extubation with regard to oxygenation indices and oxygen therapy utilization. Conclusion: In this sample of patients undergoing coronary artery bypass grafting, the use of different positive-end expiratory pressure levels before extubation did not affect gas exchange or oxygen therapy utilization in the first 6 h after endotracheal tube removal.

  6. The respiratory drive to thoracic motoneurones in the cat and its relation to the connections from expiratory bulbospinal neurones

    Science.gov (United States)

    Saywell, S A; Anissimova, N P; Ford, T W; Meehan, C F; Kirkwood, P A

    2007-01-01

    The descending control of respiratory-related motoneurones in the thoracic spinal cord remains the subject of some debate. In this study, direct connections from expiratory bulbospinal neurones to identified motoneurones were investigated using spike-triggered averaging and the strengths of connection revealed were related to the presence and size of central respiratory drive potentials in the same motoneurones. Intracellular recordings were made from motoneurones in segments T5–T9 of the spinal cord of anaesthetized cats. Spike-triggered averaging from expiratory bulbospinal neurones in the caudal medulla revealed monosynaptic EPSPs in all groups of motoneurones, with the strongest connections to expiratory motoneurones with axons in the internal intercostal nerve. In the latter, connection strength was similar irrespective of the target muscle (e.g. external abdominal oblique or internal intercostal) and the EPSP amplitude was positively correlated with the amplitude of the central respiratory drive potential of the motoneurone. For this group, EPSPs were found in 45/83 bulbospinal neurone/motoneurone pairs, with a mean amplitude of 40.5 μV. The overall strength of the connection supports previous measurements made by cross-correlation, but is about 10 times stronger than that reported in the only previous similar survey to use spike-triggered averaging. Calculations are presented to suggest that this input alone is sufficient to account for all the expiratory depolarization seen in the recorded motoneurones. However, extra sources of input, or amplification of this one, are likely to be necessary to produce a useful motoneurone output. PMID:17204500

  7. Effects of positive end-expiratory pressure and recruitment maneuvers in a ventilator-induced injury mouse model.

    Directory of Open Access Journals (Sweden)

    Laura A Cagle

    Full Text Available Positive-pressure mechanical ventilation is an essential therapeutic intervention, yet it causes the clinical syndrome known as ventilator-induced lung injury. Various lung protective mechanical ventilation strategies have attempted to reduce or prevent ventilator-induced lung injury but few modalities have proven effective. A model that isolates the contribution of mechanical ventilation on the development of acute lung injury is needed to better understand biologic mechanisms that lead to ventilator-induced lung injury.To evaluate the effects of positive end-expiratory pressure and recruitment maneuvers in reducing lung injury in a ventilator-induced lung injury murine model in short- and longer-term ventilation.5-12 week-old female BALB/c mice (n = 85 were anesthetized, placed on mechanical ventilation for either 2 hrs or 4 hrs with either low tidal volume (8 ml/kg or high tidal volume (15 ml/kg with or without positive end-expiratory pressure and recruitment maneuvers.Alteration of the alveolar-capillary barrier was noted at 2 hrs of high tidal volume ventilation. Standardized histology scores, influx of bronchoalveolar lavage albumin, proinflammatory cytokines, and absolute neutrophils were significantly higher in the high-tidal volume ventilation group at 4 hours of ventilation. Application of positive end-expiratory pressure resulted in significantly decreased standardized histology scores and bronchoalveolar absolute neutrophil counts at low- and high-tidal volume ventilation, respectively. Recruitment maneuvers were essential to maintain pulmonary compliance at both 2 and 4 hrs of ventilation.Signs of ventilator-induced lung injury are evident soon after high tidal volume ventilation (as early as 2 hours and lung injury worsens with longer-term ventilation (4 hrs. Application of positive end-expiratory pressure and recruitment maneuvers are protective against worsening VILI across all time points. Dynamic compliance can be used guide

  8. Effects of positive end-expiratory pressure and recruitment maneuvers in a ventilator-induced injury mouse model

    Science.gov (United States)

    Franzi, Lisa M.; Linderholm, Angela L.; Last, Jerold A.; Adams, Jason Y.; Harper, Richart W.

    2017-01-01

    Background Positive-pressure mechanical ventilation is an essential therapeutic intervention, yet it causes the clinical syndrome known as ventilator-induced lung injury. Various lung protective mechanical ventilation strategies have attempted to reduce or prevent ventilator-induced lung injury but few modalities have proven effective. A model that isolates the contribution of mechanical ventilation on the development of acute lung injury is needed to better understand biologic mechanisms that lead to ventilator-induced lung injury. Objectives To evaluate the effects of positive end-expiratory pressure and recruitment maneuvers in reducing lung injury in a ventilator-induced lung injury murine model in short- and longer-term ventilation. Methods 5–12 week-old female BALB/c mice (n = 85) were anesthetized, placed on mechanical ventilation for either 2 hrs or 4 hrs with either low tidal volume (8 ml/kg) or high tidal volume (15 ml/kg) with or without positive end-expiratory pressure and recruitment maneuvers. Results Alteration of the alveolar-capillary barrier was noted at 2 hrs of high tidal volume ventilation. Standardized histology scores, influx of bronchoalveolar lavage albumin, proinflammatory cytokines, and absolute neutrophils were significantly higher in the high-tidal volume ventilation group at 4 hours of ventilation. Application of positive end-expiratory pressure resulted in significantly decreased standardized histology scores and bronchoalveolar absolute neutrophil counts at low- and high-tidal volume ventilation, respectively. Recruitment maneuvers were essential to maintain pulmonary compliance at both 2 and 4 hrs of ventilation. Conclusions Signs of ventilator-induced lung injury are evident soon after high tidal volume ventilation (as early as 2 hours) and lung injury worsens with longer-term ventilation (4 hrs). Application of positive end-expiratory pressure and recruitment maneuvers are protective against worsening VILI across all time points

  9. Effects of positive end-expiratory pressure and recruitment maneuvers in a ventilator-induced injury mouse model.

    Science.gov (United States)

    Cagle, Laura A; Franzi, Lisa M; Linderholm, Angela L; Last, Jerold A; Adams, Jason Y; Harper, Richart W; Kenyon, Nicholas J

    2017-01-01

    Positive-pressure mechanical ventilation is an essential therapeutic intervention, yet it causes the clinical syndrome known as ventilator-induced lung injury. Various lung protective mechanical ventilation strategies have attempted to reduce or prevent ventilator-induced lung injury but few modalities have proven effective. A model that isolates the contribution of mechanical ventilation on the development of acute lung injury is needed to better understand biologic mechanisms that lead to ventilator-induced lung injury. To evaluate the effects of positive end-expiratory pressure and recruitment maneuvers in reducing lung injury in a ventilator-induced lung injury murine model in short- and longer-term ventilation. 5-12 week-old female BALB/c mice (n = 85) were anesthetized, placed on mechanical ventilation for either 2 hrs or 4 hrs with either low tidal volume (8 ml/kg) or high tidal volume (15 ml/kg) with or without positive end-expiratory pressure and recruitment maneuvers. Alteration of the alveolar-capillary barrier was noted at 2 hrs of high tidal volume ventilation. Standardized histology scores, influx of bronchoalveolar lavage albumin, proinflammatory cytokines, and absolute neutrophils were significantly higher in the high-tidal volume ventilation group at 4 hours of ventilation. Application of positive end-expiratory pressure resulted in significantly decreased standardized histology scores and bronchoalveolar absolute neutrophil counts at low- and high-tidal volume ventilation, respectively. Recruitment maneuvers were essential to maintain pulmonary compliance at both 2 and 4 hrs of ventilation. Signs of ventilator-induced lung injury are evident soon after high tidal volume ventilation (as early as 2 hours) and lung injury worsens with longer-term ventilation (4 hrs). Application of positive end-expiratory pressure and recruitment maneuvers are protective against worsening VILI across all time points. Dynamic compliance can be used guide the frequency

  10. Pulmonary lesion induced by low and high positive end-expiratory pressure levels during protective ventilation in experimental acute lung injury.

    Science.gov (United States)

    Pássaro, Caroline P; Silva, Pedro L; Rzezinski, Andréia F; Abrantes, Simone; Santiago, Viviane R; Nardelli, Liliane; Santos, Raquel S; Barbosa, Carolina M L; Morales, Marcelo M; Zin, Walter A; Amato, Marcelo B P; Capelozzi, Vera L; Pelosi, Paolo; Rocco, Patricia R M

    2009-03-01

    To investigate the effects of low and high levels of positive end-expiratory pressure (PEEP), without recruitment maneuvers, during lung protective ventilation in an experimental model of acute lung injury (ALI). Prospective, randomized, and controlled experimental study. University research laboratory. Wistar rats were randomly assigned to control (C) [saline (0.1 mL), intraperitoneally] and ALI [paraquat (15 mg/kg), intraperitoneally] groups. After 24 hours, each group was further randomized into four groups (six rats each) at different PEEP levels = 1.5, 3, 4.5, or 6 cm H2O and ventilated with a constant tidal volume (6 mL/kg) and open thorax. Lung mechanics [static elastance (Est, L) and viscoelastic pressure (DeltaP2, L)] and arterial blood gases were measured before (Pre) and at the end of 1-hour mechanical ventilation (Post). Pulmonary histology (light and electron microscopy) and type III procollagen (PCIII) messenger RNA (mRNA) expression were measured after 1 hour of mechanical ventilation. In ALI group, low and high PEEP levels induced a greater percentage of increase in Est, L (44% and 50%) and DeltaP2, L (56% and 36%) in Post values related to Pre. Low PEEP yielded alveolar collapse whereas high PEEP caused overdistension and atelectasis, with both levels worsening oxygenation and increasing PCIII mRNA expression. In the present nonrecruited ALI model, protective mechanical ventilation with lower and higher PEEP levels than required for better oxygenation increased Est, L and DeltaP2, L, the amount of atelectasis, and PCIII mRNA expression. PEEP selection titrated for a minimum elastance and maximum oxygenation may prevent lung injury while deviation from these settings may be harmful.

  11. Low tidal volume and high positive end-expiratory pressure mechanical ventilation results in increased inflammation and ventilator-associated lung injury in normal lungs.

    Science.gov (United States)

    Hong, Caron M; Xu, Da-Zhong; Lu, Qi; Cheng, Yunhui; Pisarenko, Vadim; Doucet, Danielle; Brown, Margaret; Aisner, Seena; Zhang, Chunxiang; Deitch, Edwin A; Delphin, Ellise

    2010-06-01

    Protective mechanical ventilation with low tidal volume (Vt) and low plateau pressure reduces mortality and decreases the length of mechanical ventilation in patients with acute respiratory distress syndrome. Mechanical ventilation that will protect normal lungs during major surgical procedures of long duration may improve postoperative outcomes. We performed an animal study comparing 3 ventilation strategies used in the operating room in normal lungs. We compared the effects on pulmonary mechanics, inflammatory mediators, and lung tissue injury. Female pigs were randomized into 3 groups. Group H-Vt/3 (n = 6) was ventilated with a Vt of 15 mL/kg predicted body weight (PBW)/positive end-expiratory pressure (PEEP) of 3 cm H(2)O, group L-Vt/3 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 3 cm H(2)O, and group L-Vt/10 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 10 cm H(2)O, for 8 hours. Hemodynamics, airway mechanics, arterial blood gases, and inflammatory markers were monitored. Bronchoalveolar lavage (BAL) was analyzed for inflammatory markers and protein concentration. The right lower lobe was assayed for mRNA of specific cytokines. The right lower lobe and right upper lobe were evaluated histologically. In contrast to groups H-Vt/3 and L-Vt/3, group L-Vt/10 exhibited a 6-fold increase in inflammatory mediators in BAL (P ventilation with high PEEP resulted in increased production of inflammatory markers. Low PEEP resulted in lower levels of inflammatory markers. High Vt/low PEEP resulted in less histologic lung injury.

  12. Influence Of Number Of Pregnancies In Peak Expiratory Flow And Body Composition Of Pregnant Women

    Directory of Open Access Journals (Sweden)

    Andrea Carla Brandao da Costa Santos

    2017-06-01

    Full Text Available Objectives: to describe and compare the mean values of the body composition and the peak expiratory flow (PEF in primigravidae and multigravidae and, to determine its correlation with obstetric, anthropometric and body composition variables. Method: it was performed a cross-sectional study of 120 healthy pregnant women at low risk, including 77 primigravidae and 43 multigravidae. The PEF was measured by spirometry and the body composition by multisegmental electrical impedance. The unpaired t test was used to compare the groups and the Pearson correlation test was used to determine the association between PEF and independent variables. A multiple linear regression was used to estimate the relationship between the dependent variable, the PEF and the independent variables. Results: the body composition variables in multigravidae women showed higher values compared to the primigravidae, being statistically significant, except for fat mass. In primigravidae, the PEF was correlated significantly with maternal age and height. In multigravidae, the PEF was correlated with maternal age, height, pre-pregnancy and current weight, total body water, extracellular water, fat mass, lean mass and fat-free mass. A Multiple linear regression analysis showed that, in primigravidae, height and maternal age were associated with PEF, being responsible for explaining 14.5% of its variability. The current weight and the maternal age explained 42.3% of peak flow variability in multigravidae. Conclusion: The PEF seemed to be influenced by the number of pregnancies. Changes were observed in relation to the body composition, as it was evidenced in correlation with the PEF in multigravidae women. Keywords: Pregnancy. Spirometry. Weight gain.

  13. Difficulty in obtaining peak expiratory flow measurements in children with acute asthma.

    Science.gov (United States)

    Gorelick, Marc H; Stevens, Molly W; Schultz, Theresa; Scribano, Philip V

    2004-01-01

    To determine the frequency with which children >or=6 years with acute asthma can perform peak expiratory flow rate measurements (PEFR) in an emergency department (ED). Data were obtained from a prospective cohort study of children with acute asthma. All children (age 2-18 years old) treated in an urban pediatric ED for an acute exacerbation during randomly selected days over a 12-month period were prospectively evaluated. According to treatment protocols, PEFR was to be measured in all children age 6 years and older before therapy and after each treatment with inhaled bronchodilators. Registered respiratory therapists obtained PEFR and evaluated whether patients were able to perform the maneuver adequately. Four hundred and fifty-six children, 6 to 18 years old (median 10 years), were enrolled; 291 (64%) had PEFR measured at least once. Of those in whom PEFR was attempted at least once, only 190 (65%) were able to perform adequately. At the start of therapy, 54% (142/262) were able to perform PEFR. Of the 120 who were unable to perform initially, 76 had another attempt at the end of the ED treatment, and 55 (72%) were still unable to perform. A total of 149 patients had attempts at PEFR both at the start and end of treatment, of these, only 71 (48%) provided valid information on both attempts. Patients unable to perform PEFR were younger (mean +/- SD = 8.7 +/- 2.8 years) than those who were able to perform successfully (11.2 +/- 3.2 years) and those with no attempts (10.0 +/- 3.4 years). Children admitted to the hospital were more likely to be unable to perform PEFR (58/126 = 46%) than those discharged from the ED (43/330 = 13%, P < 0.0001). Adequate PEFR measurements are difficult to obtain in children with acute asthma. Treatment and research protocols cannot rely exclusively on PEFR for evaluation of severity.

  14. Lung volume and expiratory flow rates from pre- to post-puberty.

    Science.gov (United States)

    Smith, Joshua R; Emerson, Sam R; Kurti, Stephanie P; Gandhi, Kirti; Harms, Craig A

    2015-08-01

    The purpose was to determine if the airways and lungs grow disproportionately from pre- to post-puberty in boys and girls. We hypothesized that the airways grow at a slower rate than lung volume (i.e. dysanapsis growth) during puberty and boys would exhibit more dysanaptic growth compared to girls. Twenty-one pre-pubescent children [11 boys (pre 10.1 ± 0.5 years, post 15.3 ± 0.5 years); 10 girls (pre 9.4 ± 1.0 years, post 14.1 ± 1.0 years)] performed pulmonary function tests (PFTs) ~5 years ago from an original cohort of 40 children. These 21 children performed PFTs, which included forced vital capacity (FVC) and forced expiratory flow at 50 % FVC (FEF50). Static pressure at 50 % of FVC [Pst(L)50 %] was estimated based on age. Dysanapsis ratio (DR) was calculated [FEF50 × FVC(-1) × Pst(L) 50 % (-1) ]. Maturation status was determined via Tanner stages. Stage of maturation was not different (p > 0.05) between boys and girls (4.2 ± 0.6 stage vs. 3.7 ± 0.7 stage, respectively). FVC and FEF50 increased (p 0.05) from pre- to post-puberty. FEF50 and FVC significantly increased and DR decreased (p puberty for both sexes. Post-puberty, boys had a significantly larger FVC, but FEF50, DR, and FEF50/FVC were not different (p > 0.05) compared to girls. These data suggest that dysanaptic growth occurs during puberty and that it is not different between boys and girls.

  15. Positive end-expiratory pressure improves gas exchange and pulmonary mechanics during partial liquid ventilation.

    Science.gov (United States)

    Kirmse, M; Fujino, Y; Hess, D; Kacmarek, R M

    1998-11-01

    Partial liquid ventilation (PLV) with perflubron (PFB) has been proposed as an adjunct to the current therapies for the acute respiratory distress syndrome (ARDS). Because PFB has been also referred to as "liquid PEEP," distributing to the most gravity-dependent regions of the lung, less attention has been paid to the amount of applied positive end-expiratory pressure (PEEP). We hypothesized that higher PEEP levels than currently applied are needed to optimize gas exchange, and that the lower inflection point (LIP) of the pressure-volume curve could be used to estimate the amount of PEEP needed when the lung is filled with PFB. Lung injury was induced in 23 sheep by repeated lung lavage with warmed saline until the PaO2/FIO2 ratio fell below 150. Five sheep were used to investigate the change of the LIP when the lung was filled with PFB in increments of 5 ml/kg/body weight to a total of 30 ml/kg/body weight. To evaluate the impact of PEEP set at LIP +1 cm H2O we randomized an additional 15 sheep to three groups with different doses (7.5 ml, 15 ml, 30 ml/kg/body weight) of PFB. In random order a PEEP of 5 cm H2O or PEEP at LIP +1 cm H2O was applied. The LIP decreased with incremental filling of PFB to a minimum at 10 ml (p PFB shifts the LIP to the left, and that setting PEEP at LIP +1 cm H2O improves gas exchange at moderate to high doses of PFB.

  16. Hepatic falciform artery

    International Nuclear Information System (INIS)

    Jaques, Paul F.; Mauro, Matthew A.; Sandhu, Jeet

    1997-01-01

    The hepatic falciform artery is an occasional terminal branch of the left or middle hepatic artery, and may provide an uncommon but important collateral route when the principal visceral arteries are occluded

  17. Double profunda brachii artery

    OpenAIRE

    Gavishiddappa A Hadimani; Jyoti V Hadimani; Ishwar B Bagoji; Shardha Bai Rathod; Balappa M Bannur

    2016-01-01

    Brachial artery (BA) is a continuation of the axillary artery at the lower border of teres major. In the cubital fossa, BA divides into radial artery and ulnar artery as terminal branches. Large branch given from the BA in the upper part is profunda brachii artery. In the present case, we noticed double profunda brachii that arises from the BA. They are profunda brachii artery 1 and profunda brachii artery 2. Profunda brachii artery 1 arises in the proximal part of the BA and profunda brachii...

  18. Cortical imaging on a head template: a simulation study using a resistor mesh model (RMM).

    Science.gov (United States)

    Chauveau, Nicolas; Franceries, Xavier; Aubry, Florent; Celsis, Pierre; Rigaud, Bernard

    2008-09-01

    The T1 head template model used in Statistical Parametric Mapping Version 2000 (SPM2), was segmented into five layers (scalp, skull, CSF, grey and white matter) and implemented in 2 mm voxels. We designed a resistor mesh model (RMM), based on the finite volume method (FVM) to simulate the electrical properties of this head model along the three axes for each voxel. Then, we introduced four dipoles of high eccentricity (about 0.8) in this RMM, separately and simultaneously, to compute the potentials for two sets of conductivities. We used the direct cortical imaging technique (CIT) to recover the simulated dipoles, using 60 or 107 electrodes and with or without addition of Gaussian white noise (GWN). The use of realistic conductivities gave better CIT results than standard conductivities, lowering the blurring effect on scalp potentials and displaying more accurate position areas when CIT was applied to single dipoles. Simultaneous dipoles were less accurately localized, but good qualitative and stable quantitative results were obtained up to 5% noise level for 107 electrodes and up to 10% noise level for 60 electrodes, showing that a compromise must be found to optimize both the number of electrodes and the noise level. With the RMM defined in 2 mm voxels, the standard 128-electrode cap and 5% noise appears to be the upper limit providing reliable source positions when direct CIT is used. The admittance matrix defining the RMM is easy to modify so as to adapt to different conductivities. The next step will be the adaptation of individual real head T2 images to the RMM template and the introduction of anisotropy using diffusion imaging (DI).

  19. A non-destructive crossbar architecture of multi-level memory-based resistor

    Science.gov (United States)

    Sahebkarkhorasani, Seyedmorteza

    Nowadays, researchers are trying to shrink the memory cell in order to increase the capacity of the memory system and reduce the hardware costs. In recent years, there has been a revolution in electronics by using fundamentals of physics to build a new memory for computer application in order to increase the capacity and decrease the power consumption. Increasing the capacity of the memory causes a growth in the chip area. From 1971 to 2012 semiconductor manufacturing process improved from 6mum to 22 mum. In May 2008, S.Williams stated that "it is time to stop shrinking". In his paper, he declared that the process of shrinking memory element has recently become very slow and it is time to use another alternative in order to create memory elements [9]. In this project, we present a new design of a memory array using the new element named Memristor [3]. Memristor is a two-terminal passive electrical element that relates the charge and magnetic flux to each other. The device remained unknown since 1971 when it was discovered by Chua and introduced as the fourth fundamental passive element like capacitor, inductor and resistor [3]. Memristor has a dynamic resistance and it can retain its previous value even after disconnecting the power supply. Due to this interesting behavior of the Memristor, it can be a good replacement for all of the Non-Volatile Memories (NVMs) in the near future. Combination of this newly introduced element with the nanowire crossbar architecture would be a great structure which is called Crossbar Memristor. Some frameworks have recently been introduced in literature that utilized Memristor crossbar array, but there are many challenges to implement the Memristor crossbar array due to fabrication and device limitations. In this work, we proposed a simple design of Memristor crossbar array architecture which uses input feedback in order to preserve its data after each read operation.

  20. Hemodynamic responses to external counterbalancing of auto-positive end-expiratory pressure in mechanically ventilated patients with chronic obstructive pulmonary disease.

    Science.gov (United States)

    Baigorri, F; de Monte, A; Blanch, L; Fernández, R; Vallés, J; Mestre, J; Saura, P; Artigas, A

    1994-11-01

    To study the effect of positive end-expiratory pressure (PEEP) on right ventricular hemodynamics and ejection fraction in patients with chronic obstructive pulmonary disease and positive alveolar pressure throughout expiration by dynamic hyperinflation (auto-PEEP). Open, prospective, controlled trial. General intensive care unit of a community hospital. Ten patients sedated and paralyzed with an acute exacerbation of chronic obstructive pulmonary disease undergoing mechanical ventilation. Insertion of a pulmonary artery catheter modified with a rapid response thermistor and a radial arterial catheter. PEEP was then increased from 0 (PEEP 0) to auto-PEEP level (PEEP = auto-PEEP) and 5 cm H2O above that (PEEP = auto-PEEP +5). At each level of PEEP, airway pressures, flow and volume, hemodynamic variables (including right ventricular ejection fraction by thermodilution technique), and blood gas analyses were recorded. The mean auto-PEEP was 6.6 +/- 2.8 cm H2O and the total PEEP reached was 12.2 +/- 2.4 cm H2O. The degree of lung inflation induced by PEEP averaged 145 +/- 87 mL with PEEP = auto-PEEP and 495 +/- 133 mL with PEEP = auto-PEEP + 5. The PEEP = auto-PEEP caused a right ventricular end-diastolic pressure increase, but there was no other significant hemodynamic change. With PEEP = auto-PEEP + 5, there was a significant increase in intravascular pressures; this amount of PEEP reduced cardiac output (from 4.40 +/- 1.38 L/min at PEEP 0 to 4.13 +/- 1.48 L/min; p 10% in only five cases and this group of patients had significantly lower right ventricular volumes than the group with less cardiac output variation (right ventricular end-diastolic volume: 64 +/- 9 vs. 96 +/- 26 mL/m2; right ventricular end-systolic volume: 38 +/- 6 vs. 65 +/- 21 mL/m2; p < .05) without significant difference in the other variables that were measured. Neither right ventricular ejection fraction nor right ventricle volumes changed as PEEP increased, but there were marked interpatient

  1. [Clinical research of using optimal compliance to determine positive end-expiratory pressure].

    Science.gov (United States)

    Xu, Lei; Feng, Quan-sheng; Lian, Fu; Shao, Xin-hua; Li, Zhi-bo; Wang, Zhi-yong; Li, Jun

    2012-07-01

    To observe the availability and security of optimal compliance strategy to titrate the optimal positive end-expiratory pressure (PEEP), compared with quasi-static pressure-volume curve (P-V curve) traced by low-flow method. Fourteen patients received mechanical ventilation with acute respiratory distress syndrome (ARDS) admitted in intensive care unit (ICU) of Tianjin Third Central Hospital from November 2009 to December 2010 were divided into two groups(n = 7). The quasi-static P-V curve method and the optimal compliance titration were used to set the optimal PEEP respectively, repeated 3 times in a row. The optimal PEEP and the consistency of repeated experiments were compared between groups. The hemodynamic parameters, oxygenation index (OI), lung compliance (C), cytokines and pulmonary surfactant-associated protein D (SP-D) concentration in plasma before and 2, 4, and 6 hours after the experiment were observed in each group. (1) There were no significant differences in gender, age and severity of disease between two groups. (2)The optimal PEEP [cm H(2)O, 1 cm H(2)O=0.098 kPa] had no significant difference between quasi-static P-V curve method group and the optimal compliance titration group (11.53 ± 2.07 vs. 10.57 ± 0.87, P>0.05). The consistency of repeated experiments in quasi-static P-V curve method group was poor, the slope of the quasi-static P-V curve in repeated experiments showed downward tendency. The optimal PEEP was increasing in each measure. There was significant difference between the first and the third time (10.00 ± 1.58 vs. 12.80 ± 1.92, P vs. 93.71 ± 5.38, temperature: 38.05 ± 0.73 vs. 36.99 ± 1.02, IL-6: 144.84 ± 23.89 vs. 94.73 ± 5.91, TNF-α: 151.46 ± 46.00 vs. 89.86 ± 13.13, SP-D: 33.65 ± 8.66 vs. 16.63 ± 5.61, MAP: 85.47 ± 9.24 vs. 102.43 ± 8.38, CCI: 3.00 ± 0.48 vs. 3.81 ± 0.81, OI: 62.00 ± 21.45 vs. 103.40 ± 37.27, C: 32.10 ± 2.92 vs. 49.57 ± 7.18, all P safety and usability.

  2. Comparison of peak expiratory flow rate and lipid profile in asymptomatic smokers and non-smokers

    International Nuclear Information System (INIS)

    Fatima, F.; Abbasi, M.A.; Jadoon, J.; Sohail, M.; Shah, J.; Afridi, U.; Noor, M.M.

    2015-01-01

    Tobacco is the major risk factor for chronic obstructive airway disease (COAD), other pulmonary diseases, cancer, cardiovascular and cerebrovascular diseases. The objective of study was to determine the mean Peak Expiratory Flow Rate (PEFR) and serum lipid profile in apparently healthy male smokers and non-smokers. Methods: This cross-sectional study was conducted in Ayub Teaching Hospital, Abbottabad from 15th December, 2009 to 15th June, 2010. Apparently healthy smokers and non-smokers from population coming to Hospital as attendants of the patients or as employees of the hospital were inducted in the study. PEFR and lipid profile of all the subjects was accessed. Results: There were total of 300 male subjects, 150 smokers and 150 non-smokers. The mean age of study subjects was 26.60 ± 5.5 years. The mean PEFR of smokers was 450.62l/min and that of non-smokers was 494.81 L/min, the difference being statistically significant (p-value <0.05).The mean total cholesterol of smokers is 5.30 ± 0.86 mmol/l and it was 3.84 ± 0.54 mmol/l in non-smokers. Mean serum Triacyl Glycerols (TAGs) and Low Density Lipoproteins (LDL) cholesterol of smokers was 2.04 ± 0.38 and 3.5 ± 0.83 mmol/l whereas it was 1.44 ± 0.52 and 2.02 ± 0.66 mmol/l in non-smokers. Mean High Density Lipo-protein (HDL) of smokers was 0.86 ± 0.30 mmol/l and of non-smokers is 1.20 ± 0.41 mmo/l. There was statistically significant difference between serum lipid profile of smokers and non-smokers (p<0.05). the mean serum Total Cholesterol (TC), TAGs and LDL were significantly higher in smokers as compared to non-smokers. However HDL was significantly lower in smokers in comparison to non-smokers. Conclusion: There was statistically significant difference between PEFR of smokers and non-smokers. Higher and significant mean values of TC, TAG and LDL-C was observed in smokers as compared to non-smokers. (author)

  3. Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors

    Energy Technology Data Exchange (ETDEWEB)

    Aghili Yajadda, Mir Massoud [CSIRO Manufacturing Flagship, P.O. Box 218, Lindfield NSW 2070 (Australia)

    2014-10-21

    We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300 K) at low and high DC bias voltages (0.001 mV–50 V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

  4. Comparison of three resistor network division circuits for the readout of 4×4 pixel SiPM arrays

    International Nuclear Information System (INIS)

    Stratos, David; Maria, Georgiou; Eleftherios, Fysikopoulos; George, Loudos

    2013-01-01

    The purpose of this study is to investigate the behavior of a flexible SensL's silicon photomultiplier array (SPMArray4) photodetector for possible applications in PET imaging. We have designed and evaluated three different resistor network division circuits to read out the signal outputs of a 4×4 pixel SiPM array. We have applied firstly (i) a symmetric resistive voltage division circuit, secondly (ii) a symmetric resistive charge division circuit and thirdly (iii) a charge division multiplexing resistor network reducing the 16 pixel outputs to 4 position signals. In the first circuit the SensL SPMArray4-A0 preamplification electronics and a SPMArray4-A1 evaluation board providing the 16 pixels voltage outputs were used, before the symmetric resistive voltage network. We reduced the 16 voltage signals firstly to 4X and 4Y coordinate signals. Then those signals were further reduced to 2X and 2Y position signals connected via a resistor network. In the second readout circuit we have used the same technique but without the preamplification stage. The third circuit is based on a discretized positioning circuit, which multiplexes the 16 signals from the SiPM array to 4 position signals. The 4 position signals (Xa, Xb, Yc and Yd) were digitized using a free running sampling technique. An FPGA (Spartan 6 LX16) was used for triggering and signal processing of the pulses. We acquired raw images and energy histograms of a BGO and a CsI:Na pixilated scintillator under 22 Na excitation. A clear visualization of the discrete 2×2×5 mm 3 pixilated BGO scintillator elements as well as the 1×1×5 mm 3 pixilated CsI:Na crystal array was achieved with all applied readout circuits. The symmetric resistive charge division circuit provides higher peak to valley ratio than the other readout circuits. Τhe sensitivity and the energy resolution remained almost constant for the three circuits

  5. Development and characterisation of silicon photomultipliers with bulk-integrated quench resistors for future applications in particle and astroparticle physics

    International Nuclear Information System (INIS)

    Jendrysik, Christian

    2014-01-01

    This thesis deals with the development and characterisation of a novel silicon photomultiplier concept with bulk-integrated quench resistors. The approach allows the realisation of a free entrance window and high fill factors, which leads to an improvement of the detection efficiency. With first prototype productions a proof of concept was possible. A full characterisation provided promising results, in particular with respect to the photon detection efficiency. By customising the simulation tools, a reliable description of the devices was achieved. In addition, conceptual studies of the next device generation demonstrated the possibility of single cell readout, expanding the application range of those detectors to particle tracking.

  6. Integrated one diode-one resistor architecture in nanopillar SiOx resistive switching memory by nanosphere lithography.

    Science.gov (United States)

    Ji, Li; Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Tsai, Tsung-Ming; Chang, Kuan-Chang; Chen, Min-Chen; Chang, Ting-Chang; Sze, Simon M; Yu, Edward T; Lee, Jack C

    2014-02-12

    We report on a highly compact, one diode-one resistor (1D-1R) nanopillar device architecture for SiOx-based ReRAM fabricated using nanosphere lithography (NSL). The intrinsic SiOx-based resistive switching element and Si diode are self-aligned on an epitaxial silicon wafer using NSL and a deep-Si-etch process without conventional photolithography. AC-pulse response in 50 ns regime, multibit operation, and good reliability are demonstrated. The NSL process provides a fast and economical approach to large-scale patterning of high-density 1D-1R ReRAM with good potential for use in future applications.

  7. Degradation of GaAs/AlGaAs Quantized Hall Resistors With Alloyed AuGe/Ni Contacts

    OpenAIRE

    Lee, Kevin C.

    1998-01-01

    Careful testing over a period of 6 years of a number of GaAs/AlGaAs quantized Hall resistors (QHR) made with alloyed AuGe/Ni contacts, both with and without passivating silicon nitride coatings, has resulted in the identification of important mechanisms responsible for degradation in the performance of the devices as resistance standards. Covering the contacts with a film, such as a low-temperature silicon nitride, that is impervious to humidity and other contaminants in the atmosphere preven...

  8. Effects of brief smoking cessation education with expiratory carbon monoxide measurement on level of motivation to quit smoking.

    Science.gov (United States)

    Choi, Won-Young; Kim, Cheol-Hwan; Lee, Ok-Gyu

    2013-05-01

    Smoking rates among Korean adult males is still high despite multifaceted efforts to reduce it. In Korea, there have been several studies on the effectiveness of smoking cessation education for inpatients, health check-ups, and smoking cessation clinics. However, there haven't been any studies on the effectiveness of smoking cessation education conducted outside the hospital. This study investigated effectiveness of brief education on smoking cessation with an expiratory carbon monoxide (CO) measurement outside the hospital among adult male office-workers in Korea. From April 1st to May 10th, 2012, we conducted a controlled trial among 95 adult male office workers over the age of 19 who smoke outside, in a public place in Seoul by cluster sampling. For the education group, we provided smoking cessation education for about 5 to 10 minutes, measured the expiratory CO level, and made the subjects complete questionnaires, while only self-help materials on quitting smoking were given to the control group. After 4 weeks, we evaluated the change in the level of motivation or success to quit smoking in both groups via e-mail or mobile phone. In the education group, the level of motivation to quit smoking was improved significantly. A multiple logistic regression analysis showed that the odds ratio of improved motivation to quit smoking in the education group was 28.10 times higher than that of the control group. Brief education on smoking cessation with expiratory CO measurement conducted outside the hospital could enhance the level of motivation to quit smoking.

  9. Effects of recruitment maneuver and positive end-expiratory pressure on respiratory mechanics and transpulmonary pressure during laparoscopic surgery.

    Science.gov (United States)

    Cinnella, Gilda; Grasso, Salvatore; Spadaro, Savino; Rauseo, Michela; Mirabella, Lucia; Salatto, Potito; De Capraris, Antonella; Nappi, Luigi; Greco, Pantaleo; Dambrosio, Michele

    2013-01-01

    The authors tested the hypothesis that during laparoscopic surgery, Trendelenburg position and pneumoperitoneum may worsen chest wall elastance, concomitantly decreasing transpulmonary pressure, and that a protective ventilator strategy applied after pneumoperitoneum induction, by increasing transpulmonary pressure, would result in alveolar recruitment and improvement in respiratory mechanics and gas exchange. In 29 consecutive patients, a recruiting maneuver followed by positive end-expiratory pressure 5 cm H(2)O maintained until the end of surgery was applied after pneumoperitoneum induction. Respiratory mechanics, gas exchange, blood pressure, and cardiac index were measured before (T(BSL)) and after pneumoperitoneum with zero positive end-expiratory pressure (T(preOLS)), after recruitment with positive end-expiratory pressure (T(postOLS)), and after peritoneum desufflation with positive end-expiratory pressure (T(end)). Esophageal pressure was used for partitioning respiratory mechanics between lung and chest wall (data are mean ± SD): on T(preOLS), chest wall elastance (E(cw)) and elastance of the lung (E(L)) increased (8.2 ± 0.9 vs. 6.2 ± 1.2 cm H(2)O/L, respectively, on T(BSL); P = 0.00016; and 11.69 ± 1.68 vs. 9.61 ± 1.52 cm H(2)O/L on T(BSL); P = 0.0007). On T(postOLS), both chest wall elastance and E(L) decreased (5.2 ± 1.2 and 8.62 ± 1.03 cm H(2)O/L, respectively; P = 0.00015 vs. T(preOLS)), and Pao(2)/inspiratory oxygen fraction improved (491 ± 107 vs. 425 ± 97 on T(preOLS); P = 0.008) remaining stable thereafter. Recruited volume (the difference in lung volume for the same static airway pressure) was 194 ± 80 ml. Pplat(RS) remained stable while inspiratory transpulmonary pressure increased (11.65 + 1.37 cm H(2)O vs. 9.21 + 2.03 on T(preOLS); P = 0.007). All respiratory mechanics parameters remained stable after abdominal desufflation. Hemodynamic parameters remained stable throughout the study. In patients submitted to laparoscopic surgery in

  10. Investigation on powder metallurgy Cr-Si-Ta-Al alloy target for high-resistance thin film resistors with low temperature coefficient of resistance

    International Nuclear Information System (INIS)

    Wang, X.Y.; Zhang, Z.S.; Bai, T.

    2010-01-01

    The sputtering target for high-resistance thin film resistors plays a decisive role in temperature coefficient of resistance (TCR). Silicon-rich chromium (Cr)-silicon (Si) target was designed and smelted for high-resistance thin film resistors with low TCR. Valve metal tantalum (Ta) and aluminum (Al) were introduced to the Cr-Si target to improve the performance of the target prepared. The measures for grain refining in smelting Cr-Si-Ta-Al target were taken to improve the performance of the prepared target. The mechanism and role of grain refinement were discussed in the paper. The phase structure of the prepared target was detected by X-ray diffraction (XRD). Rate of temperature drop was studied to reduce the internal stress of alloy target and conquer the easy cracking disadvantage of silicon-rich target. The electrical properties of sputtered thin film resistors were tested to evaluate the performance of the prepared target indirectly.

  11. Conduction in rectangular quasi-one-dimensional and two-dimensional random resistor networks away from the percolation threshold.

    Science.gov (United States)

    Kiefer, Thomas; Villanueva, Guillermo; Brugger, Jürgen

    2009-08-01

    In this study we investigate electrical conduction in finite rectangular random resistor networks in quasione and two dimensions far away from the percolation threshold p(c) by the use of a bond percolation model. Various topologies such as parallel linear chains in one dimension, as well as square and triangular lattices in two dimensions, are compared as a function of the geometrical aspect ratio. In particular we propose a linear approximation for conduction in two-dimensional systems far from p(c), which is useful for engineering purposes. We find that the same scaling function, which can be used for finite-size scaling of percolation thresholds, also applies to describe conduction away from p(c). This is in contrast to the quasi-one-dimensional case, which is highly nonlinear. The qualitative analysis of the range within which the linear approximation is legitimate is given. A brief link to real applications is made by taking into account a statistical distribution of the resistors in the network. Our results are of potential interest in fields such as nanostructured or composite materials and sensing applications.

  12. Versatile tunable current-mode universal biquadratic filter using MO-DVCCs and MOSFET-based electronic resistors.

    Science.gov (United States)

    Chen, Hua-Pin

    2014-01-01

    This paper presents a versatile tunable current-mode universal biquadratic filter with four-input and three-output employing only two multioutput differential voltage current conveyors (MO-DVCCs), two grounded capacitors, and a well-known method for replacement of three grounded resistors by MOSFET-based electronic resistors. The proposed configuration exhibits high-output impedance which is important for easy cascading in the current-mode operations. The proposed circuit can be used as either a two-input three-output circuit or a three-input single-output circuit. In the operation of two-input three-output circuit, the bandpass, highpass, and bandreject filtering responses can be realized simultaneously while the allpass filtering response can be easily obtained by connecting appropriated output current directly without using additional stages. In the operation of three-input single-output circuit, all five generic filtering functions can be easily realized by selecting different three-input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no inverting-type input current signals are imposed. All the passive and active sensitivities are low. Postlayout simulations were carried out to verify the functionality of the design.

  13. Versatile Tunable Current-Mode Universal Biquadratic Filter Using MO-DVCCs and MOSFET-Based Electronic Resistors

    Directory of Open Access Journals (Sweden)

    Hua-Pin Chen

    2014-01-01

    Full Text Available This paper presents a versatile tunable current-mode universal biquadratic filter with four-input and three-output employing only two multioutput differential voltage current conveyors (MO-DVCCs, two grounded capacitors, and a well-known method for replacement of three grounded resistors by MOSFET-based electronic resistors. The proposed configuration exhibits high-output impedance which is important for easy cascading in the current-mode operations. The proposed circuit can be used as either a two-input three-output circuit or a three-input single-output circuit. In the operation of two-input three-output circuit, the bandpass, highpass, and bandreject filtering responses can be realized simultaneously while the allpass filtering response can be easily obtained by connecting appropriated output current directly without using additional stages. In the operation of three-input single-output circuit, all five generic filtering functions can be easily realized by selecting different three-input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no inverting-type input current signals are imposed. All the passive and active sensitivities are low. Postlayout simulations were carried out to verify the functionality of the design.

  14. IDENTIFIKASI NILAI HAMBAT JENIS ARANG KAYU, ARANG KULIT MANGGA, DAN ARANG KULIT PISANG: BAHAN ALTERNATIF PENGGANTI RESISTOR FILM KARBON

    Directory of Open Access Journals (Sweden)

    Intan Kusumawati

    2014-05-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui nilai hambat jenis pada arang kayu, arang kulit mangga, dan arang kulit pisang sebagai bahan alternatif pengganti resistor film karbon. Pada penelitian ini dilakukan penumbukkan arang kayu, arang kulit mangga, dan kulit pisang sehingga dihasilkan bubuk arang yang halus melalui proses penyaringan. Setelah itu dilakukan pemampatan arang kayu dalam pipet/sedotan plastik dengan luas permukaan (A = 4,08 x 10-4 cm. Kemudian hambatan diukur menggunakan multimeter dan dilakukan perhitungan hambat jenis arang tersebut. Hasil penelitian menunjukkan bahwa arang kayu (0,73 x 106 m memiliki nilai hambat yang tinggi sehingga hambat jenisnya juga lebih tinggi dibandingkan dengan arang kulit mangga (0,28 x 106  m dan arang kulit pisang (0,24 x 106 m. Hal ini dikarenakan terjadi proses karbonisasi sempurna dalam pembuatan arang kayu. Oleh karena nilai hambatan yang dapat terbaca pada multimeter hanya menggunakan batas skala yang besar (Mega Ohm, maka arang kulit kayu, arang kulit mangga, dan arang kulit pisang hanya dapat dijadikan sebagai bahan alternatif pengganti resistor film karbon dengan ukuran nilai hambatan besar.

  15. Microstructure and electrical properties of slug-type resistors based on B4C and TiC - ESCA - XPS and impedance spectroscopy investigations

    International Nuclear Information System (INIS)

    Klimiec, E.; Zaraska, W.; Stobiecki, T.; Bak, W.; Starzyk, F.

    2000-01-01

    The microstructure and electrical properties of slug-type resistors based on B 4 C and TiC were investigated. From XPS measurements was deducted that Ti in TiO 2 is in intermediate oxidation number between Ti +4 and Ti +3 . The impedance of both type of resistors is independent on frequency in the range from 10 3 to 10 4 Hz, only very subtle differences above 10 4 Hz are observed. The metallic type conductivity in TiC and semiconducting in B 4 C was established. (author)

  16. Numerical and experimental study of expiratory flow in the case of major upper airway obstructions with fluid structure interaction

    Science.gov (United States)

    Chouly, F.; van Hirtum, A.; Lagrée, P.-Y.; Pelorson, X.; Payan, Y.

    2008-02-01

    This study deals with the numerical prediction and experimental description of the flow-induced deformation in a rapidly convergent divergent geometry which stands for a simplified tongue, in interaction with an expiratory airflow. An original in vitro experimental model is proposed, which allows measurement of the deformation of the artificial tongue, in condition of major initial airway obstruction. The experimental model accounts for asymmetries in geometry and tissue properties which are two major physiological upper airway characteristics. The numerical method for prediction of the fluid structure interaction is described. The theory of linear elasticity in small deformations has been chosen to compute the mechanical behaviour of the tongue. The main features of the flow are taken into account using a boundary layer theory. The overall numerical method entails finite element solving of the solid problem and finite differences solving of the fluid problem. First, the numerical method predicts the deformation of the tongue with an overall error of the order of 20%, which can be seen as a preliminary successful validation of the theory and simulations. Moreover, expiratory flow limitation is predicted in this configuration. As a result, both the physical and numerical models could be useful to understand this phenomenon reported in heavy snorers and apneic patients during sleep.

  17. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    work place and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

  18. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    International Nuclear Information System (INIS)

    Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H.

    2012-01-01

    and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

  19. Respiratory effects of low versus high tidal volume with or without positive end-expiratory pressure in anesthetized dogs with healthy lungs.

    Science.gov (United States)

    De Monte, Valentina; Bufalari, Antonello; Grasso, Salvatore; Ferrulli, Fabienne; Crovace, Alberto Maria; Lacitignola, Luca; Staffieri, Francesco

    2018-05-01

    OBJECTIVE To evaluate the impact of 2 tidal volumes (T V s) with or without positive end-expiratory pressure (PEEP) on lung mechanics, aeration, and gas exchange in healthy anesthetized dogs. ANIMALS 40 mixed-breed dogs with healthy lungs. PROCEDURES Anesthetized dogs were randomly assigned to 4 groups (n = 10/group) with different ventilatory settings: T V of 8 mL/kg and PEEP of 0 cm H 2 O (low T V group), T V of 8 mL/kg and PEEP of 5 cm H 2 O (low T V plus PEEP group), T V of 15 mL/kg and PEEP of 0 cm H 2 O (high T V group), or T V of 15 mL/kg and PEEP of 5 cm H 2 O (high T V plus PEEP group). Expired CO 2 and respiratory rate were titrated on the basis of a predetermined stepwise protocol. Gas exchange, respiratory mechanics, and pulmonary aeration were evaluated by means of CT 30 minutes after starting mechanical ventilation at the assigned setting. RESULTS Partial pressures of arterial and expired CO 2 were higher in the low T V and low T V plus PEEP groups than in the high T V and high T V plus PEEP groups. Peak and plateau airway pressures were higher in the PEEP group than in the other groups. Static lung compliance was higher in the high T V plus PEEP group than in the low T V group. Relative percentages of atelectatic and poorly aerated lung were lower in the high T V plus PEEP group than in the other groups. Oxygenation was similar among groups. CONCLUSIONS AND CLINICAL RELEVANCE Differences in T V and PEEP application during mechanical ventilation may affect respiratory function in anesthetized dogs with healthy lungs. Ventilation with a T V of 15 mL/kg and PEEP of 5 cm H 2 O significantly improved lung compliance and reduced the amount of atelectatic and poorly aerated lung.

  20. Positive expiratory pressure therapy versus other airway clearance techniques for bronchiectasis.

    Science.gov (United States)

    Lee, Annemarie L; Burge, Angela T; Holland, Anne E

    2017-09-27

    People with bronchiectasis experience chronic cough and sputum production and require the prescription of airway clearance techniques (ACTs). A common type of ACT prescribed is positive expiratory pressure (PEP) therapy. A previous review has suggested that ACTs including PEP therapy are beneficial compared to no treatment in people with bronchiectasis. However, the efficacy of PEP therapy in a stable clinical state or during an acute exacerbation compared to other ACTs in bronchiectasis is unknown. The primary aim of this review was to determine the effects of PEP therapy compared with other ACTs on health-related quality of life (HRQOL), rate of acute exacerbations, and incidence of hospitalisation in individuals with stable or an acute exacerbation of bronchiectasis.Secondary aims included determining the effects of PEP therapy upon physiological outcomes and clinical signs and symptoms compared with other ACTs in individuals with stable or an acute exacerbation of bronchiectasis. We searched the Cochrane Airways Group Specialised Register of Trials, PEDro and clinical trials registries from inception to February 2017 and we handsearched relevant journals. Randomised controlled parallel and cross-over trials that compared PEP therapy versus other ACTs in participants with bronchiectasis. We used standard methodological procedures as outlined by Cochrane. Nine studies involving 213 participants met the inclusion criteria, of which seven were cross-over in design. All studies included adults with bronchiectasis, with eight including participants in a stable clinical state and one including participants experiencing an acute exacerbation. Eight studies used oscillatory PEP therapy, using either a Flutter or Acapella device and one study used Minimal PEP therapy. The comparison intervention differed between studies. The methodological quality of studies was poor, with cross-over studies including suboptimal or no washout period, and a lack of blinding of

  1. Effect of simultaneous application of postural techniques and expiratory muscle strength training on the enhancement of the swallowing function of patients with dysphagia caused by parkinson?s disease

    OpenAIRE

    Byeon, Haewon

    2016-01-01

    [Purpose] This study aimed to investigate the effect of simultaneous application of postural techniques and expiratory muscle strength training on the enhancement of the swallowing function of patients with dysphagia caused by Parkinson?s disease. [Subjects and Methods] The subjects of this study were 18 patients who received simultaneous application of postural techniques and expiratory muscle strength training and 15 patients who received expiratory muscle strength training only. Postural t...

  2. Hepatic artery aneurysms (HAAs)

    International Nuclear Information System (INIS)

    Nosratini, H.

    2004-01-01

    The hepatic artery aneurysms are rare, especially in interahepatic branches, The frequency consists of 75-80% extrahepatic and 20-25% intrahepatic. Catheterization is achieved usually from common femoral artery, other methods implemented in the case of unsuccessful catheterization from femoral artery, are translumbar and brachial catheterization. The study consist of 565 patients that were referred to the angiography ward, During seven years of assessment, five cases of hepatic artery aneurysm were found; this is a rare condition reported in the English literature. In the literature as well as in this case report the hepatic artery aneurysms are rare. In reported series the extrahepatic artery aneurysms are found more often than in the intrahepatic artery aneurysm but in this case report intrahepatic artery aneurysms are more than extrahepatic one. (author)

  3. Bilateral renal artery variation

    OpenAIRE

    Üçerler, Hülya; Üzüm, Yusuf; İkiz, Z. Aslı Aktan

    2014-01-01

    Each kidney is supplied by a single renal artery, although renal artery variations are common. Variations of the renal arteryhave become important with the increasing number of renal transplantations. Numerous studies describe variations in renalartery anatomy. Especially the left renal artery is among the most critical arterial variations, because it is the referred side forresecting the donor kidney. During routine dissection in a formalin fixed male cadaver, we have found a bilateral renal...

  4. Model of 1/f noise in ion implanted resistors as a function of the resistance, determined by a reverse bias voltage

    International Nuclear Information System (INIS)

    Beck, H.G.E.

    1979-01-01

    A model is presented for the 1/f noise in ion-implanted resistors. The resistance was changed by a reverse bias voltage. The model explains the experimentally found square dependence between the relative 1/f noise intensity C/C 0 and the relative change in resistance R/R 0 . (author)

  5. High-performance and low-power rewritable SiOx 1 kbit one diode-one resistor crossbar memory array.

    Science.gov (United States)

    Wang, Gunuk; Lauchner, Adam C; Lin, Jian; Natelson, Douglas; Palem, Krishna V; Tour, James M

    2013-09-14

    An entire 1-kilobit crossbar device based upon SiOx resistive memories with integrated diodes has been made. The SiOx -based one diode-one resistor device system has promise to satisfy the prerequisite conditions for next generation non-volatile memory applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Array of Chemosensitive Resistors with Composites of Gas Chromatography (GC) Materials and Carbon Black for Detection and Recognition of VOCs: A Basic Study

    Science.gov (United States)

    Wyszynski, Bartosz; Yatabe, Rui; Nakao, Atsuo; Nakatani, Masaya; Oki, Akio; Oka, Hiroaki; Toko, Kiyoshi

    2017-01-01

    Mimicking the biological olfaction, large odor-sensor arrays can be used to acquire a broad range of chemical information, with a potentially high degree of redundancy, to allow for enhanced control over the sensitivity and selectivity of artificial olfaction systems. The arrays should consist of the largest possible number of individual sensing elements while being miniaturized. Chemosensitive resistors are one of the sensing platforms that have a potential to satisfy these two conditions. In this work we test viability of fabricating a 16-element chemosensitive resistor array for detection and recognition of volatile organic compounds (VOCs). The sensors were fabricated using blends of carbon black and gas chromatography (GC) stationary-phase materials preselected based on their sorption properties. Blends of the selected GC materials with carbon black particles were subsequently coated over chemosensitive resistor devices and the resulting sensors/arrays evaluated in exposure experiments against vapors of pyrrole, benzenal, nonanal, and 2-phenethylamine at 150, 300, 450, and 900 ppb. Responses of the fabricated 16-element array were stable and differed for each individual odorant sample, proving the blends of GC materials with carbon black particles can be effectively used for fabrication of large odor-sensing arrays based on chemosensitive resistors. The obtained results suggest that the proposed sensing devices could be effective in discriminating odor/vapor samples at the sub-ppm level. PMID:28696353

  7. Ion-implanted capacitively coupled silicon strip detectors with integrated polysilicon bias resistors processed on a 100 mm wafer

    International Nuclear Information System (INIS)

    Hietanen, I.; Lindgren, J.; Orava, R.; Tuuva, T.; Voutilainen, M.; Brenner, R.; Andersson, M.; Leinonen, K.; Ronkainen, H.

    1991-01-01

    Double-sided silicon strip detectors with integrated coupling capacitors and polysilicon resistors have been processed on a 100 mm wafer. A detector with an active area of 19x19 mm 2 was connected to LSI readout electronics and tested. The strip pitch of the detector is 25 μm on the p-side and 50 μm on the n-side. The readout pitch is 50 μm on both sides. The number of readout strips is 774 and the total number of strips is 1161. On the p-side a signal-to-noise of 35 has been measured using a 90 Sr β-source. The n-side has been studied using a laser. (orig.)

  8. Second Sound Measurement using SMD resistors to simulate Quench locations on the 704 MHZ Single-Cell Cavity at CERN

    CERN Document Server

    Liao, K; Ciapala, E; Junginger, T; Weingarten, W

    2012-01-01

    Oscillating Superleak Transducers (OSTs) containing flexible porous membranes are widely used to detect the so-called second sound temperature wave when a quench event occurs in a superconducting RF cavity. In principle, from the measured speed of this wave and the travel time between the quench event and several OSTs, the location of the quench sites can be derived by triangulation. Second sound behaviour has been simulated through different surface mount (SMD) resistors setups on a Superconducting Proton Linac (SPL) test cavity, to help understanding the underlying physics and improve quench localisation. Experiments are described that have been conducted to search for explanation of heat transfer during cavity quench that causes contradictory triangulation results.

  9. Resistor capacitor, primitive variable solution of buoyant fluid flow within an enclosure with highly temperature dependent viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Burns, S.P. [Texas Univ., Austin, TX (United States); Gianoulakis, S.E. [Sandia National Labs., Albuquerque, NM (United States)

    1995-07-01

    A numerical solution for buoyant natural convection within a square enclosure containing a fluid with highly temperature dependent viscosity is presented. Although the fluid properties employed do not represent any real fluid, the large variation in the fluid viscosity with temperature is characteristic of turbulent flow modeling with eddy-viscosity concepts. Results are obtained using a primitive variable formulation and the resistor method. The results presented include velocity, temperature and pressure distributions within the enclosure as well as shear stress and heat flux distributions along the enclosure walls. Three mesh refinements were employed and uncertainty values are suggested for the final mesh refinement. These solutions are part of a contributed benchmark solution set for the subject problem.

  10. Prediction of multiple resonance characteristics by an extended resistor-inductor-capacitor circuit model for plasmonic metamaterials absorbers in infrared.

    Science.gov (United States)

    Xu, Xiaolun; Li, Yongqian; Wang, Binbin; Zhou, Zili

    2015-10-01

    The resonance characteristics of plasmonic metamaterials absorbers (PMAs) are strongly dependent on geometric parameters. A resistor-inductor-capacitor (RLC) circuit model has been extended to predict the resonance wavelengths and the bandwidths of multiple magnetic polaritons modes in PMAs. For a typical metallic-dielectric-metallic structure absorber working in the infrared region, the developed model describes the correlation between the resonance characteristics and the dimensional sizes. In particular, the RLC model is suitable for not only the fundamental resonance mode, but also for the second- and third-order resonance modes. The prediction of the resonance characteristics agrees fairly well with those calculated by the finite-difference time-domain simulation and the experimental results. The developed RLC model enables the facilitation of designing multi-band PMAs for infrared radiation detectors and thermal emitters.

  11. Mechanisms of Low-Temperature Nitridation Technology on a TaN Thin Film Resistor for Temperature Sensor Applications.

    Science.gov (United States)

    Chen, Huey-Ru; Chen, Ying-Chung; Chang, Ting-Chang; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chu, Tian-Jian; Shih, Chih-Cheng; Chuang, Nai-Chuan; Wang, Kao-Yuan

    2016-12-01

    In this letter, we propose a novel low-temperature nitridation technology on a tantalum nitride (TaN) thin film resistor (TFR) through supercritical carbon dioxide (SCCO2) treatment for temperature sensor applications. We also found that the sensitivity of temperature of the TaN TFR was improved about 10.2 %, which can be demonstrated from measurement of temperature coefficient of resistance (TCR). In order to understand the mechanism of SCCO2 nitridation on the TaN TFR, the carrier conduction mechanism of the device was analyzed through current fitting. The current conduction mechanism of the TaN TFR changes from hopping to a Schottky emission after the low-temperature SCCO2 nitridation treatment. A model of vacancy passivation in TaN grains with nitrogen and by SCCO2 nitridation treatment is eventually proposed to increase the isolation ability in TaN TFR, which causes the transfer of current conduction mechanisms.

  12. Internal resistor of multi-functional tunnel barrier for selectivity and switching uniformity in resistive random access memory.

    Science.gov (United States)

    Lee, Sangheon; Woo, Jiyong; Lee, Daeseok; Cha, Euijun; Hwang, Hyunsang

    2014-01-01

    In this research, we analyzed the multi-functional role of a tunnel barrier that can be integrated in devices. This tunnel barrier, acting as an internal resistor, changes its resistance with applied bias. Therefore, the current flow in the devices can be controlled by a tunneling mechanism that modifies the tunnel barrier thickness for non-linearity and switching uniformity of devices. When a device is in a low-resistance state, the tunnel barrier controls the current behavior of the device because most of the bias is applied to the tunnel barrier owing to its higher resistance. Furthermore, the tunnel barrier induces uniform filament formation during set operation with the tunnel barrier controlling the current flow.

  13. Field effect of screened charges: electrical detection of peptides and proteins by a thin-film resistor.

    Science.gov (United States)

    Lud, Simon Q; Nikolaides, Michael G; Haase, Ilka; Fischer, Markus; Bausch, Andreas R

    2006-02-13

    For many biotechnological applications the label-free detection of biomolecular interactions is becoming of outstanding importance. In this Article we report the direct electrical detection of small peptides and proteins by their intrinsic charges using a biofunctionalized thin-film resistor. The label-free selective and quantitative detection of small peptides and proteins is achieved using hydrophobized silicon-on-insulator (SOI) substrates functionalized with lipid membranes that incorporate metal-chelating lipids. The response of the nanometer-thin conducting silicon film to electrolyte screening effects is taken into account to determine quantitatively the charges of peptides. It is even possible to detect peptides with a single charge and to distinguish single charge variations of the analytes even in physiological electrolyte solutions. As the device is based on standard semiconductor technologies, parallelization and miniaturization of the SOI-based biosensor is achievable by standard CMOS technologies and thus a promising basis for high-throughput screening or biotechnological applications.

  14. Directly writing resistor, inductor and capacitor to composite functional circuits: a super-simple way for alternative electronics.

    Directory of Open Access Journals (Sweden)

    Yunxia Gao

    Full Text Available BACKGROUND: The current strategies for making electronic devices are generally time, water, material and energy consuming. Here, the direct writing of composite functional circuits through comprehensive use of GaIn10-based liquid metal inks and matching material is proposed and investigated, which is a rather easy going and cost effective electronics fabrication way compared with the conventional approaches. METHODS: Owing to its excellent adhesion and electrical properties, the liquid metal ink was demonstrated as a generalist in directly making various basic electronic components such as planar resistor, inductor and capacitor or their combination and thus composing circuits with expected electrical functions. For a precise control of the geometric sizes of the writing, a mask with a designed pattern was employed and demonstrated. Mechanisms for justifying the chemical components of the inks and the magnitudes of the target electronic elements so as to compose various practical circuits were disclosed. RESULTS: Fundamental tests on the electrical components including capacitor and inductor directly written on paper with working time up to 48 h and elevated temperature demonstrated their good stability and potential widespread adaptability especially when used in some high frequency circuits. As the first proof-of-concept experiment, a typical functional oscillating circuit including an integrated chip of 74HC04 with a supply voltage of 5 V, a capacitor of 10 nF and two resistors of 5 kΩ and 1 kΩ respectively was directly composed on paper through integrating specific electrical elements together, which presented an oscillation frequency of 8.8 kHz. CONCLUSIONS: The present method significantly extends the roles of the metal ink in recent works serving as only a single electrical conductor or interconnecting wires. It opens the way for directly writing out complex functional circuits or devices on different substrates. Such circuit

  15. Directly writing resistor, inductor and capacitor to composite functional circuits: a super-simple way for alternative electronics.

    Science.gov (United States)

    Gao, Yunxia; Li, Haiyan; Liu, Jing

    2013-01-01

    The current strategies for making electronic devices are generally time, water, material and energy consuming. Here, the direct writing of composite functional circuits through comprehensive use of GaIn10-based liquid metal inks and matching material is proposed and investigated, which is a rather easy going and cost effective electronics fabrication way compared with the conventional approaches. Owing to its excellent adhesion and electrical properties, the liquid metal ink was demonstrated as a generalist in directly making various basic electronic components such as planar resistor, inductor and capacitor or their combination and thus composing circuits with expected electrical functions. For a precise control of the geometric sizes of the writing, a mask with a designed pattern was employed and demonstrated. Mechanisms for justifying the chemical components of the inks and the magnitudes of the target electronic elements so as to compose various practical circuits were disclosed. Fundamental tests on the electrical components including capacitor and inductor directly written on paper with working time up to 48 h and elevated temperature demonstrated their good stability and potential widespread adaptability especially when used in some high frequency circuits. As the first proof-of-concept experiment, a typical functional oscillating circuit including an integrated chip of 74HC04 with a supply voltage of 5 V, a capacitor of 10 nF and two resistors of 5 kΩ and 1 kΩ respectively was directly composed on paper through integrating specific electrical elements together, which presented an oscillation frequency of 8.8 kHz. The present method significantly extends the roles of the metal ink in recent works serving as only a single electrical conductor or interconnecting wires. It opens the way for directly writing out complex functional circuits or devices on different substrates. Such circuit composition strategy has generalized purpose and can be extended to more

  16. Modeling error and stability of endothelial cytoskeletal membrane parameters based on modeling transendothelial impedance as resistor and capacitor in series.

    Science.gov (United States)

    Bodmer, James E; English, Anthony; Brady, Megan; Blackwell, Ken; Haxhinasto, Kari; Fotedar, Sunaina; Borgman, Kurt; Bai, Er-Wei; Moy, Alan B

    2005-09-01

    Transendothelial impedance across an endothelial monolayer grown on a microelectrode has previously been modeled as a repeating pattern of disks in which the electrical circuit consists of a resistor and capacitor in series. Although this numerical model breaks down barrier function into measurements of cell-cell adhesion, cell-matrix adhesion, and membrane capacitance, such solution parameters can be inaccurate without understanding model stability and error. In this study, we have evaluated modeling stability and error by using a chi(2) evaluation and Levenberg-Marquardt nonlinear least-squares (LM-NLS) method of the real and/or imaginary data in which the experimental measurement is compared with the calculated measurement derived by the model. Modeling stability and error were dependent on current frequency and the type of experimental data modeled. Solution parameters of cell-matrix adhesion were most susceptible to modeling instability. Furthermore, the LM-NLS method displayed frequency-dependent instability of the solution parameters, regardless of whether the real or imaginary data were analyzed. However, the LM-NLS method identified stable and reproducible solution parameters between all types of experimental data when a defined frequency spectrum of the entire data set was selected on the basis of a criterion of minimizing error. The frequency bandwidth that produced stable solution parameters varied greatly among different data types. Thus a numerical model based on characterizing transendothelial impedance as a resistor and capacitor in series and as a repeating pattern of disks is not sufficient to characterize the entire frequency spectrum of experimental transendothelial impedance.

  17. Jet pump assisted artery

    Science.gov (United States)

    1975-01-01

    A procedure for priming an arterial heat pump is reported; the procedure also has a means for maintaining the pump in a primed state. This concept utilizes a capillary driven jet pump to create the necessary suction to fill the artery. Basically, the jet pump consists of a venturi or nozzle-diffuser type constriction in the vapor passage. The throat of this venturi is connected to the artery. Thus vapor, gas, liquid, or a combination of the above is pumped continuously out of the artery. As a result, the artery is always filled with liquid and an adequate supply of working fluid is provided to the evaporator of the heat pipe.

  18. Differential Effects of Intraoperative Positive End-expiratory Pressure (PEEP) on Respiratory Outcome in Major Abdominal Surgery Versus Craniotomy

    DEFF Research Database (Denmark)

    de Jong, Myrthe A C; Ladha, Karim S; Melo, Marcos F Vidal

    2015-01-01

    OBJECTIVES: In this study, we examined whether (1) positive end-expiratory pressure (PEEP) has a protective effect on the risk of major postoperative respiratory complications in a cohort of patients undergoing major abdominal surgeries and craniotomies, and (2) the effect of PEEP is differed......: Within the entire study population (major abdominal surgeries and craniotomies), we found an association between application of PEEP ≥5 cmH2O and a decreased risk of postoperative respiratory complications compared with PEEP 5 cmH2O was associated with a significant lower...... undergoing major abdominal surgery. Our data suggest that default mechanical ventilator settings should include PEEP of 5-10 cmH2O during major abdominal surgery....

  19. [The influence of positive end-expiratory pressure on cerebral blood flow and cerebrovascular autoregulation in patients with acute respiratory distress syndrome].

    Science.gov (United States)

    Yang, Chunli; Chen, Zhi; Lu, Yuanhua; He, Huiwei; Zeng, Weihua

    2014-05-01

    To explore the influence of different positive end-expiratory pressure (PEEP) levels on cerebral blood flow (CBF) and cerebrovascular autoregulation in patients with acute respiratory distress syndrome(ARDS). A prospective study was conducted. Moderate or severe ARDS patients admitted to Department of Critical Care Medicine of Jiangxi Provincial People's Hospital from January 1st, 2013 to October 1st, 2013 were enrolled. The changes in hemodynamics, respiratory mechanics and gas exchange under different levels of PEEP were observed. CBF velocity of middle cerebral artery (MCA) was measured using transcranial Doppler (TCD), and breath-holding index (BHI) was also calculated. 35 patients with ARDS were included. The oxygenation index (OI), peak inspiratory pressure (PIP), plat pressure (Pplat) and central venous pressure (CVP) were markedly elevated (OI: 324.7±117.2 mmHg vs. 173.4±95.8 mmHg, t=5.913, P=0.000; PIP: 34.7±9.1 cmH2O vs. 26.1±7.9 cmH2O,t=4.222, P=0.000; Pplat: 30.5±8.4 cmH2O vs. 22.2±7.1 cmH2O, t=4.465, P=0.000; CVP: 12.1±3.5 mmHg vs. 8.8±2.2 mmHg, t=4.723, P=0.000) when PEEP was increased from (6.4±1.0) cmH2O to (14.5±2.0) cmH2O (1 cmH2O=0.098 kPa). But no significant difference in the heart rate (85.5±19.1 beats/min vs. 82.7±17.3 beats/min, t=0.643, P=0.523), mean arterial pressure (73.5±12.4 mmHg vs. 76.4±15.1 mmHg, t=0.878, P=0.383) and CBF velocity of MCA [peak systolic flow velocity (Vmax): 91.26±17.57 cm/s vs. 96.64±18.71 cm/s, t=1.240, P=0.219; diastolic flow velocity (Vmin): 31.54±7.71 cm/s vs. 33.87±8.53 cm/s, t=1.199, P=0.235; mean velocity (Vmean): 51.19±12.05 cm/s vs. 54.27±13.36 cm/s, t=1.013, P=0.315] was found. 18 patients with BHI<0.1 at baseline demonstrated that cerebral vasomotor reactivity was poor. BHI was slightly decreased with increase in PEEP (0.78±0.16 vs. 0.86±0.19, t=1.905, P=0.061). Some of moderate or severe ARDS patients without central nervous system disease have independent of preexisting cerebral

  20. Quantitative assessment of cross-sectional area of small pulmonary vessels in patients with COPD using inspiratory and expiratory MDCT

    International Nuclear Information System (INIS)

    Matsuura, Yukiko; Kawata, Naoko; Yanagawa, Noriyuki; Sugiura, Toshihiko; Sakurai, Yoriko; Sato, Misuzu; Iesato, Ken; Terada, Jiro; Sakao, Seiichiro; Tada, Yuji; Tanabe, Nobuhiro; Suzuki, Yoichi; Tatsumi, Koichiro

    2013-01-01

    Objectives: Structural and functional changes in pulmonary vessels are prevalent at the initial stages of chronic obstructive pulmonary disease (COPD). These vascular alterations can be assessed using cross-sectional area (CSA) of small pulmonary vessels. However, neither in non-COPD smokers nor in COPD patients it has been defined whether the structural changes of pulmonary vessels detected by paired inspiratory and expiratory CT scans are associated with emphysematous changes. We quantified the CSA and low attenuation area (LAA) and evaluated the changes in these parameters in the inspiratory and expiratory phases. Materials and methods: Fifty consecutive non-COPD smokers and COPD patients were subjected to multi detector-row CT and the percentage of vessels with a CSA less than 5 mm 2 as well as the percentage LAA for total lung area (%CSA < 5, %LAA, respectively) were calculated. Results: The %CSA < 5 correlated negatively with %LAA. The %CSA < 5 was lower in COPD patients with emphysema as compared with non-COPD smokers and COPD patients with or without mild emphysema. In addition, the %CSA < 5 was lower in the no/mild emphysema subgroup as compared with non-COPD smokers. The respiratory phase change of %CSA < 5 in COPD patients was greater than that in non-COPD smokers. Conclusion: The percentage of small pulmonary vessels decreased as emphysematous changes increase, and this decrease was observed even in patients with no/mild emphysema. Furthermore, respiratory phase changes in CSA were higher in COPD patients than in non-COPD smokers

  1. ERGONOMIC CONSIDERATION OF THE EFFECT OF FLOUR DUST ON PEAK EXPIRATORY FLOW RATE OF BAKERS IN ABEOKUTA, OGUN STATE

    Directory of Open Access Journals (Sweden)

    Adekunle Ibrahim MUSA

    2017-06-01

    Full Text Available Flour dusts are one of the most harmful chemicals in the bakery industries which could lead to serious heart and lung diseases. This study investigated the effect of flour dust on Peak Expiratory Flow Rate of male bakers in Abeokuta, Ogun State, Nigeria with the relationship to the anthropometrical parameters. A total of One hundred Eighty (180 male participants were investigated, where ninety (90 participants were bakers and ninety (90 individuals as control group. The Peak expiratory flow rate (PEFR and anthropometrical parameters of the participant were measured using mini-Wright peak flow meter (PFM 20, OMRON and Detecto PD300MDHR (Cardinal Scale manufacturing company, USA column scale with digital height rod was used to measure body mass [kg] and height (cm respectively. The PEFR and anthropometrical parameters of the bakers and control groups were analysed using descriptive statistics and T-test with SPSS. The results showed that lower PEFR, 182.67 ± 16.34 L/min existed in bakers compared to 287.67 ± 17.02 L/min in the control study. The result also showed that a significant correlation exist between body mass, height and age (P < 0.01, PEFR, height (P < 0.05 and years of exposure (P < 0.01 of the bakers respectively. Furthermore, the results also showed that workers in the dusting and mixing of flour are at a risk of developing related pulmonary function impairment such as asthma. The study concluded that there is need to develop an effective intervention strategy, treatment seeking behaviour through awareness programs to prevent lung impairment diseases among the bakery workers.

  2. Quantitative assessment of cross-sectional area of small pulmonary vessels in patients with COPD using inspiratory and expiratory MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, Yukiko, E-mail: matsuyuki_future@yahoo.co.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Kawata, Naoko, E-mail: chumito_03@yahoo.co.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Yanagawa, Noriyuki, E-mail: yanagawa@ho.chiba-u.ac.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Sugiura, Toshihiko, E-mail: sugiura@js3.so-net.ne.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Sakurai, Yoriko, E-mail: yoliri@nifty.com [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Sato, Misuzu, E-mail: mis_misuzu@yahoo.co.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Iesato, Ken, E-mail: iesato_k@yahoo.co.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Terada, Jiro, E-mail: jirotera@chiba-u.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Sakao, Seiichiro, E-mail: sakao@faculty.chiba-u.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Tada, Yuji, E-mail: ytada@faculty.chiba-u.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Tanabe, Nobuhiro, E-mail: ntanabe@faculty.chiba-u.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Suzuki, Yoichi, E-mail: ysuzuki@faculty.chiba-u.jp [Department of public Health, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan); Tatsumi, Koichiro, E-mail: tatsumi@faculty.chiba-u.jp [Department of Respirology, Graduate School of Medicine, Chiba University, Chiba 260-8670 Japan (Japan)

    2013-10-01

    Objectives: Structural and functional changes in pulmonary vessels are prevalent at the initial stages of chronic obstructive pulmonary disease (COPD). These vascular alterations can be assessed using cross-sectional area (CSA) of small pulmonary vessels. However, neither in non-COPD smokers nor in COPD patients it has been defined whether the structural changes of pulmonary vessels detected by paired inspiratory and expiratory CT scans are associated with emphysematous changes. We quantified the CSA and low attenuation area (LAA) and evaluated the changes in these parameters in the inspiratory and expiratory phases. Materials and methods: Fifty consecutive non-COPD smokers and COPD patients were subjected to multi detector-row CT and the percentage of vessels with a CSA less than 5 mm{sup 2} as well as the percentage LAA for total lung area (%CSA < 5, %LAA, respectively) were calculated. Results: The %CSA < 5 correlated negatively with %LAA. The %CSA < 5 was lower in COPD patients with emphysema as compared with non-COPD smokers and COPD patients with or without mild emphysema. In addition, the %CSA < 5 was lower in the no/mild emphysema subgroup as compared with non-COPD smokers. The respiratory phase change of %CSA < 5 in COPD patients was greater than that in non-COPD smokers. Conclusion: The percentage of small pulmonary vessels decreased as emphysematous changes increase, and this decrease was observed even in patients with no/mild emphysema. Furthermore, respiratory phase changes in CSA were higher in COPD patients than in non-COPD smokers.

  3. [Modification of expiratory peak flow (EPF) in 14 asthmatic subjects from Benin by short duration exercise training].

    Science.gov (United States)

    Lawani, M M; Hounkpatin, S; Akplogan, B

    2006-01-01

    Asthma is a world wide public health problem. It is the most commom chronic disease of school age children. Its severity is in constant increase. The frequency of the hospitalizations for asthma increased in practically all countries. Physical exercises and sport are used more and more as therapeutic means, in northern deveopped countries of where it was very early understood that it is necessary to integrate the asthmatic subjects into a program of specific physical training. This study undertaken in south saharian african country considers also assiduity in a physical training program as the factor of increase in the expiratory peak flow, of reinforcement of some principal muscles necessary to the improvement, and of the respiratory function of the asthmatic subject. Physical exercise is used as a non pharmacological therapy of asthma. This transversal study was carried out on fourteen asthmatic subjects of colleges in Porto-Novo's town, aged 15 years old to 25 years, of the two sexes. The results showed that: the Expiratory Peak Flow of Point (EPF) of the subjects at the beginning of the program is lower than the minimal average value of the group whatever the sex; the subjects average EPF increased from approximately 35% compared to the average at the beginning of the program; the subjects from family with asthmatic line, are much more inclined with respiratory embarrassments post-exercises than those who did not come from it; the respiratory embarrassments post-exercises noticed in the first weeks, grew blurred before the end of the program. This study suggests physical exercise adapted to the asthmatic subjects for the improvement of their health.

  4. Inspiratory and expiratory HRCT findings in Behcet's disease and correlation with pulmonary function tests

    Energy Technology Data Exchange (ETDEWEB)

    Oezer, Caner [Department of Radiology, Mersin University, Faculty of Medicine, Mersin (Turkey)]. E-mail: cozer@mersin.edu.tr; Duce, Meltem Nass [Department of Radiology, Mersin University, Faculty of Medicine, Mersin (Turkey); Ulubas, Bahar [Department of Respiratory Disease, Mersin University, Faculty of Medicine, Mersin (Turkey); Bicer, Ali [Department of Physical Medicine and Rehabilitation, Mersin University, Faculty of Medicine, Mersin (Turkey); Tuersen, Uemit [Department of Dermatology, Mersin University, Faculty of Medicine, Mersin (Turkey); Apaydin, F. Demir [Department of Radiology, Mersin University, Faculty of Medicine, Mersin (Turkey); Yildiz, Altan [Department of Radiology, Mersin University, Faculty of Medicine, Mersin (Turkey); Camdeviren, Handan [Department of Biostatistics, Mersin University, Faculty of Medicine, Mersin (Turkey)

    2005-10-01

    Purpose: The purpose of our study was to describe the pulmonary parenchymal changes of Behcet's disease using high-resolution computed tomography and to correlate them with pulmonary function tests. Materials and methods: Thirty-four patients with Behcet's disease (18 men, 16 women), 3 of whom were symptomatic, were included as the study group. Four of 34 patients were smokers. Twenty asymptomatic volunteers (12 men, 8 women), 4 of whom were smokers, constituted the control group. The pulmonary function tests and high-resolution computed tomography were performed for both groups. Results: Inspiratory high-resolution computed tomography findings were abnormal in nine patients (26.5%) of the study group. In eight patients, there were multiple abnormalities, whereas one patient had only one abnormality. Pleural thickening and irregularities, major fissure thickening, emphysematous changes, bronchiectasis, parenchymal bands, and irregular densities, and parenchymal nodules were the encountered abnormalities. Inspiratory high-resolution computed tomography scans were normal in the control group. On expiratory scans, there was statistically significant difference between study group and control group when air trapping, especially grades 3 and 4, was compared (P < 0.01). Pulmonary function tests of both the study and the control groups were in normal ranges, and there was no statistically significant difference between the two groups according to pulmonary function tests (P > 0.05). Discussion and conclusion: High-resolution computed tomography is sensitive in the demonstration of pulmonary changes in patients with Behcet's disease. End-expiratory high-resolution computed tomography examination is very useful and necessary to show the presence of air trapping, thus the presence of small airway disease, even if the patient is asymptomatic or has normal pulmonary function tests.

  5. Diagnosis of bronchiectasis and airway wall thickening in children with cystic fibrosis. Objective airway-artery quantification

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Wieying; Tiddens, Harm A.W.M. [Erasmus MC - Sophia Children' s Hospital, Department of Pediatric Pulmonology and Allergology, Rotterdam (Netherlands); Erasmus MC, Department of Radiology, Rotterdam (Netherlands); Bruijne, Marleen de [Erasmus MC, Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Rotterdam (Netherlands); University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Petersen, Jens [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Nasserinejad, Kazem [Erasmus MC Cancer Institute, HOVON Data Center, Clinical Trial Center, Rotterdam (Netherlands); Erasmus MC, Department of Biostatistics, Rotterdam (Netherlands); Ozturk, Hadiye [Erasmus MC - Sophia Children' s Hospital, Department of Pediatric Pulmonology and Allergology, Rotterdam (Netherlands); Chen, Yong [General Hospital of Ningxia Medical University, Department of Radiology, Yinchuan (China); Perez-Rovira, Adria [Erasmus MC - Sophia Children' s Hospital, Department of Pediatric Pulmonology and Allergology, Rotterdam (Netherlands); Erasmus MC, Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Rotterdam (Netherlands)

    2017-11-15

    To quantify airway and artery (AA)-dimensions in cystic fibrosis (CF) and control patients for objective CT diagnosis of bronchiectasis and airway wall thickness (AWT). Spirometer-guided inspiratory and expiratory CTs of 11 CF and 12 control patients were collected retrospectively. Airway pathways were annotated semi-automatically to reconstruct three-dimensional bronchial trees. All visible AA-pairs were measured perpendicular to the airway axis. Inner, outer and AWT (outer-inner) diameter were divided by the adjacent artery diameter to compute A{sub in}A-, A{sub out}A- and A{sub WT}A-ratios. AA-ratios were predicted using mixed-effects models including disease status, lung volume, gender, height and age as covariates. Demographics did not differ significantly between cohorts. Mean AA-pairs CF: 299 inspiratory; 82 expiratory. Controls: 131 inspiratory; 58 expiratory. All ratios were significantly larger in inspiratory compared to expiratory CTs for both groups (p<0.001). A{sub out}A- and A{sub WT}A-ratios were larger in CF than in controls, independent of lung volume (p<0.01). Difference of A{sub out}A- and A{sub WT}A-ratios between patients with CF and controls increased significantly for every following airway generation (p<0.001). Diagnosis of bronchiectasis is highly dependent on lung volume and more reliably diagnosed using outer airway diameter. Difference in bronchiectasis and AWT severity between the two cohorts increased with each airway generation. (orig.)

  6. Incidence of tracheobronchomalacia associated with pulmonary emphysema. Detection with paired inspiratory-expiratory multidetector computed tomography using a low-dose technique

    International Nuclear Information System (INIS)

    Inoue, Masanori; Hasegawa, Ichiro; Nakano, Keiko; Yamaguchi, Kazuhiro; Kuribayashi, Sachio

    2009-01-01

    The purpose of this study was to evaluate the frequency of tracheobronchomalacia (TBM) associated with pulmonary emphysema with paired inspiratory-expiratory multidetector computed tomography (MDCT) using a low-dose technique. This study included 56 consecutive patients (55 men, 1 woman; mean age 68.9 years) with pulmonary emphysema who had undergone paired inspiratory-expiratory CT scanning with a low-dose technique (40 mA). All images were retrospectively examined by two thoracic radiologists in a blinded fashion. The diagnosis of TBM was based on the standard criterion of >50% reduction in the cross-sectional area of the tracheobronchial lumen at the end-expiratory phase. A mild TBM criterion of >30% reduction was also reviewed. All patients underwent pulmonary function tests. The relation between the forced expiratory volume in 1 s (FEV 1.0% ) and TBM was statistically analyzed. Four (7.1%) and eight (14.3%) patients were diagnosed as TBM based on the standard and mild criteria, respectively. In four patients, the percentages of luminal narrowing were 63.4% and 51.2%, respectively for tracheomalacia and 59.2% and 62.0%, respectively, for bronchomalacia. The FEV 1.0% values between patients with and without TBM showed no statistical difference. The incidence of TBM associated with pulmonary emphysema was 7.1% with the standard criterion. It is possible that TBM has been underdiagnosed in a number of patients with pulmonary emphysema. (author)

  7. Influence of Changing the Diameter of the Bubble Generator Bottle and Expiratory Limb on Bubble CPAP: An in vitro Study

    Directory of Open Access Journals (Sweden)

    Chun-Shan Wu

    2012-12-01

    Conclusion: The size and submergence depth of an expiratory limb of a CPAP circuit, the diameter of the bubble generator bottle, and the compliance of the model lung all influence the magnitude and frequency of the transmitted pressure waveform. Therefore, these factors may affect lung volume recruitment and breathing efficiency in bubble CPAP.

  8. Lung-protective ventilation in intensive care unit and operation room : Tidal volume size, level of positive end-expiratory pressure and driving pressure

    NARCIS (Netherlands)

    Serpa Neto, A.

    2017-01-01

    Several investigations have shown independent associations between three ventilator settings – tidal volume size, positive end–expiratory pressure (PEEP) and driving pressure – and outcomes in patients with the acute respiratory distress syndrome (ARDS). There is an increasing notion that similar

  9. Distribution of peak expiratory flow variability by age, gender and smoking habits in a random population sample aged 20-70 yrs

    NARCIS (Netherlands)

    Boezen, H M; Schouten, J. P.; Postma, D S; Rijcken, B

    1994-01-01

    Peak expiratory flow (PEF) variability can be considered as an index of bronchial lability. Population studies on PEF variability are few. The purpose of the current paper is to describe the distribution of PEF variability in a random population sample of adults with a wide age range (20-70 yrs),

  10. Effects of Inhaled Fenoterol and Positive End-Expiratory Pressure on the Respiratory Mechanics of Patients with Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Claude Guerin

    2005-01-01

    Full Text Available BACKGROUND: During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD, applying external positive end-expiratory pressure (PEEPe will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists.

  11. Associations between positive end-expiratory pressure and outcome of patients without ARDS at onset of ventilation: a systematic review and meta-analysis of randomized controlled trials

    NARCIS (Netherlands)

    Serpa Neto, Ary; Filho, Roberto Rabello; Cherpanath, Thomas; Determann, Rogier; Dongelmans, Dave A.; Paulus, Frederique; Tuinman, Pieter Roel; Pelosi, Paolo; de Abreu, Marcelo Gama; Schultz, Marcus J.

    2016-01-01

    The aim of this investigation was to compare ventilation at different levels of positive end-expiratory pressure (PEEP) with regard to clinical important outcomes of intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) at onset of ventilation. Meta-analysis of

  12. Effect of a mixture of pyridostigmine and atropine on forced expiratory volume (FEV1), and serum cholinesterase activity in normal subjects

    DEFF Research Database (Denmark)

    Feldt-Rasmussen, B F; Gefke, Kaj; Mosbech, H

    1985-01-01

    injection with a decrease to 27 +/- 5% (mean +/- SEM) of the original activity. Forced expiratory volume in the first 1s (FEV1) was measured at fixed time intervals for 90 min. No decrease in FEV1 was observed; on the contrary, there was a small increase. We conclude that atropine effectively antagonizes...

  13. Testicular artery arising from an aberrant right renal artery | Suluba ...

    African Journals Online (AJOL)

    This case report we discovered the rare variation of the origin of the right testicular artery arising from the right aberrant renal artery with double renal artery irrigating both left and right kidneys. These variations in the testicular arteries and renal arteries have implication to surgical procedures such as orchidopexy repair for ...

  14. Duplicated middle cerebral artery

    Science.gov (United States)

    Perez, Jesus; Machado, Calixto; Scherle, Claudio; Hierro, Daniel

    2009-01-01

    Duplicated middle cerebral artery (DMCA) is an anomalous vessel arising from the internal carotid artery. The incidence DMCA is relatively law, and an association between this anomaly and cerebral aneurysms has been documented. There is a controversy whether DMCA may have perforating arteries. This is an important fact to consider in aneurysm surgery. We report the case of a 34-year-old black woman who suffered a subarachnoid hemorrhage and the angiography a left DMCA, and an aneurysm in an inferior branch of the main MCA. The DMCA and the MCA had perforating arteries. The aneurysm was clipped without complications. The observation of perforating arteries in our patient confirms that the DMCA may have perforating arteries. This is very important to be considered in cerebral aneurysms surgery. Moreover, the DMCA may potentially serve as a collateral blood supply to the MCA territory in cases of MCA occlusion. PMID:22140405

  15. Roles of preoperative arterial blood gas tests in the surgical treatment of scoliosis with moderate or severe pulmonary dysfunction.

    Science.gov (United States)

    Liu, Jia-Ming; Shen, Jian-Xiong; Zhang, Jian-Guo; Zhao, Hong; Li, Shu-Gang; Zhao, Yu; Qiu, Giu-Xing

    2012-01-01

    It has been stated that preoperative pulmonary function tests are essential to assess the surgical risk in patients with scoliosis. Arterial blood gas tests have also been used to evaluate pulmonary function before scoliotic surgery. However, few studies have been reported. The aim of this study was to investigate the roles of preoperative arterial blood gas tests in the surgical treatment of scoliosis with moderate or severe pulmonary dysfunction. This study involved scoliotic patients with moderate or severe pulmonary dysfunction (forced vital capacity treatment between January 2002 and April 2010. A total of 73 scoliotic patients (23 males and 50 females) with moderate or severe pulmonary dysfunction were included. The average age of the patients was 16.53 years (ranged 10 - 44). The demographic distribution, medical records, and radiographs of all patients were collected. All patients received arterial blood gas tests and pulmonary function tests before surgery. The arterial blood gas tests included five parameters: partial pressure of arterial oxygen, partial pressure of arterial carbon dioxide, alveolar-arterial oxygen tension gradient, pH, and standard bases excess. The pulmonary function tests included three parameters: forced expiratory volume in 1 second ratio, forced vital capacity ratio, and peak expiratory flow ratio. All five parameters of the arterial blood gas tests were compared between the two groups with or without postoperative pulmonary complications by variance analysis. Similarly, all three parameters of the pulmonary function tests were compared. The average coronal Cobb angle before surgery was 97.42° (range, 50° - 180°). A total of 15 (20.5%) patients had postoperative pulmonary complications, including hypoxemia in 5 cases (33.3%), increased requirement for postoperative ventilatory support in 4 (26.7%), pneumonia in 2 (13.3%), atelectasis in 2 (13.3%), pneumothorax in 1 (6.7%), and hydrothorax in 1 (6.7%). No significant differences

  16. Popliteal artery entrapment syndrome.

    LENUS (Irish Health Repository)

    O'Leary, D P

    2010-01-01

    Popliteal artery entrapment syndrome is a rare abnormality of the anatomical relationship between the popliteal artery and adjacent muscles or fibrous bands in the popliteal fossa. The following is a case report of a 19 year old female, in whom popliteal artery entrapment syndrome was diagnosed, and successfully treated surgically. A review of literature is also presented and provides details on how PAES is classified, diagnosed both clinically and radiologically, and treated surgically.

  17. Normal variation of hepatic artery

    International Nuclear Information System (INIS)

    Kim, Inn; Nam, Myung Hyun; Rhim, Hyun Chul; Koh, Byung Hee; Seo, Heung Suk; Kim, Soon Yong

    1987-01-01

    This study was an analyses of blood supply of the liver in 125 patients who received hepatic arteriography and abdominal aortography from Jan. 1984 to Dec. 1986 at the Department of Radiology of Hanyang University Hospital. A. Variations in extrahepatic arteries: 1. The normal extrahepatic artery pattern occurred in 106 of 125 cases (84.8%) ; Right hepatic and left hepatic arteries arising from the hepatic artery proper and hepatic artery proper arising from the common hepatic artery. 2. The most common type of variation of extrahepatic artery was replaced right hepatic artery from superior mesenteric artery: 6 of 125 cases (4.8%). B. Variations in intrahepatic arteries: 1. The normal intrahepatic artery pattern occurred in 83 of 125 cases (66.4%). Right hepatic and left hepatic arteries arising from the hepatic artery proper and middle hepatic artery arising from lower portion of the umbilical point of left hepatic artery. 2. The most common variation of intrahepatic arteries was middle hepatic artery. 3. Among the variation of middle hepatic artery; Right, middle and left hepatic arteries arising from the same location at the hepatic artery proper was the most common type; 17 of 125 cases (13.6%)

  18. Renal Branch Artery Stenosis

    DEFF Research Database (Denmark)

    Andersson, Zarah; Thisted, Ebbe; Andersen, Ulrik Bjørn

    2017-01-01

    Renovascular hypertension is a common cause of pediatric hypertension. In the fraction of cases that are unrelated to syndromes such as neurofibromatosis, patients with a solitary stenosis on a branch of the renal artery are common and can be diagnostically challenging. Imaging techniques...... that perform well in the diagnosis of main renal artery stenosis may fall short when it comes to branch artery stenosis. We report 2 cases that illustrate these difficulties and show that a branch artery stenosis may be overlooked even by the gold standard method, renal angiography....

  19. Imaging the vertebral artery

    Energy Technology Data Exchange (ETDEWEB)

    Tay, Keng Yeow; U-King-Im, Jean Marie; Trivedi, Rikin A.; Higgins, Nicholas J.; Cross, Justin J.; Antoun, Nagui M. [Addenbrooke' s Hospital and University of Cambridge, Department of Radiology, Cambridge (United Kingdom); Davies, John R.; Weissberg, Peter L. [Addenbrooke' s Hospital and University of Cambridge, Division of Cardiovascular Medicine, Cambridge (United Kingdom); Gillard, Jonathan H. [Addenbrooke' s Hospital and University of Cambridge, Department of Radiology, Cambridge (United Kingdom); Addenbrooke' s Hospitald, University Department of Radiology, Cambridge (United Kingdom)

    2005-07-01

    Although conventional intraarterial digital subtraction angiography remains the gold standard method for imaging the vertebral artery, noninvasive modalities such as ultrasound, multislice computed tomographic angiography and magnetic resonance angiography are constantly improving and are playing an increasingly important role in diagnosing vertebral artery pathology in clinical practice. This paper reviews the current state of vertebral artery imaging from an evidence-based perspective. Normal anatomy, normal variants and a number of pathological entities such as vertebral atherosclerosis, arterial dissection, arteriovenous fistula, subclavian steal syndrome and vertebrobasilar dolichoectasia are discussed. (orig.)

  20. Imaging the vertebral artery

    International Nuclear Information System (INIS)

    Tay, Keng Yeow; U-King-Im, Jean Marie; Trivedi, Rikin A.; Higgins, Nicholas J.; Cross, Justin J.; Antoun, Nagui M.; Davies, John R.; Weissberg, Peter L.; Gillard, Jonathan H.

    2005-01-01

    Although conventional intraarterial digital subtraction angiography remains the gold standard method for imaging the vertebral artery, noninvasive modalities such as ultrasound, multislice computed tomographic angiography and magnetic resonance angiography are constantly improving and are playing an increasingly important role in diagnosing vertebral artery pathology in clinical practice. This paper reviews the current state of vertebral artery imaging from an evidence-based perspective. Normal anatomy, normal variants and a number of pathological entities such as vertebral atherosclerosis, arterial dissection, arteriovenous fistula, subclavian steal syndrome and vertebrobasilar dolichoectasia are discussed. (orig.)

  1. Congenital coronary artery fistula

    International Nuclear Information System (INIS)

    Oh, Yeon Hee; Kim, Hong; Zeon, Seoc Kil; Suh, Soo Jhi

    1986-01-01

    Congenital coronary artery fistula (CCAF) is communication of a coronary artery or its main branch with one of the atria or ventricles, the coronary sinus, the superior vena cava, or the pulmonary artery. In Korean peoples, only 4 cases of the CCAF were reported as rare as worldwide and authors want to report another case of CCAF, confirmed by operation. 10-year-old girl shows a fistula between sinus node artery of the right coronary artery and right atrium on root aortogram with left-to-right shunt and Qp/Qs=1.58, in which simple ligation of the sinus node artery from right coronary artery was performed. All of the 5 Korean CCAF (4 were previously reported and 1 of authors) were originated from right coronary artery, and of which 4 were opening into right ventricle and 1 of authors were into right atrium. Associated cardiac anomaly was noted in only 1 case as single coronary artery. Ages were from 9 months of age to 10 years old and no adult left case were found. 3 were female and 2 were male patients.

  2. Paired maximum inspiratory and expiratory plain chest radiographs for assessment of airflow limitation in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Takashi, E-mail: tkino@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Kawayama, Tomotaka, E-mail: kawayama_tomotaka@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Imamura, Youhei, E-mail: mamura_youhei@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Sakazaki, Yuki, E-mail: sakazaki@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Hirai, Ryo, E-mail: hirai_ryou@kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Ishii, Hidenobu, E-mail: shii_hidenobu@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Suetomo, Masashi, E-mail: jin_t_f_c@yahoo.co.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Matsunaga, Kazuko, E-mail: kmatsunaga@kouhoukai.or.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Azuma, Koichi, E-mail: azuma@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Fujimoto, Kiminori, E-mail: kimichan@med.kurume-u.ac.jp [Department of Radiology, Kurume University School of Medicine, Kurume (Japan); Hoshino, Tomoaki, E-mail: hoshino@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2015-04-15

    Highlights: •It is often to use computed tomography (CT) scan for diagnosis of chronic obstructive pulmonary disease. •CT scan is more expensive and higher. •A plane chest radiography more simple and cheap. Moreover, it is useful as detection of pulmonary emphysema, but not airflow limitation. •Our study demonstrated that the maximum inspiratory and expiratory plane chest radiography technique could detect severe airflow limitations. •We believe that the technique is helpful to diagnose the patients with chronic obstructive pulmonary disease. -- Abstract: Background: The usefulness of paired maximum inspiratory and expiratory (I/E) plain chest radiography (pCR) for diagnosis of chronic obstructive pulmonary disease (COPD) is still unclear. Objectives: We examined whether measurement of the I/E ratio using paired I/E pCR could be used for detection of airflow limitation in patients with COPD. Methods: Eighty patients with COPD (GOLD stage I = 23, stage II = 32, stage III = 15, stage IV = 10) and 34 control subjects were enrolled. The I/E ratios of frontal and lateral lung areas, and lung distance between the apex and base on pCR views were analyzed quantitatively. Pulmonary function parameters were measured at the same time. Results: The I/E ratios for the frontal lung area (1.25 ± 0.01), the lateral lung area (1.29 ± 0.01), and the lung distance (1.18 ± 0.01) were significantly (p < 0.05) reduced in COPD patients compared with controls (1.31 ± 0.02 and 1.38 ± 0.02, and 1.22 ± 0.01, respectively). The I/E ratios in frontal and lateral areas, and lung distance were significantly (p < 0.05) reduced in severe (GOLD stage III) and very severe (GOLD stage IV) COPD as compared to control subjects, although the I/E ratios did not differ significantly between severe and very severe COPD. Moreover, the I/E ratios were significantly correlated with pulmonary function parameters. Conclusions: Measurement of I/E ratios on paired I/E pCR is simple and

  3. Paired maximum inspiratory and expiratory plain chest radiographs for assessment of airflow limitation in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Kinoshita, Takashi; Kawayama, Tomotaka; Imamura, Youhei; Sakazaki, Yuki; Hirai, Ryo; Ishii, Hidenobu; Suetomo, Masashi; Matsunaga, Kazuko; Azuma, Koichi; Fujimoto, Kiminori; Hoshino, Tomoaki

    2015-01-01

    Highlights: •It is often to use computed tomography (CT) scan for diagnosis of chronic obstructive pulmonary disease. •CT scan is more expensive and higher. •A plane chest radiography more simple and cheap. Moreover, it is useful as detection of pulmonary emphysema, but not airflow limitation. •Our study demonstrated that the maximum inspiratory and expiratory plane chest radiography technique could detect severe airflow limitations. •We believe that the technique is helpful to diagnose the patients with chronic obstructive pulmonary disease. -- Abstract: Background: The usefulness of paired maximum inspiratory and expiratory (I/E) plain chest radiography (pCR) for diagnosis of chronic obstructive pulmonary disease (COPD) is still unclear. Objectives: We examined whether measurement of the I/E ratio using paired I/E pCR could be used for detection of airflow limitation in patients with COPD. Methods: Eighty patients with COPD (GOLD stage I = 23, stage II = 32, stage III = 15, stage IV = 10) and 34 control subjects were enrolled. The I/E ratios of frontal and lateral lung areas, and lung distance between the apex and base on pCR views were analyzed quantitatively. Pulmonary function parameters were measured at the same time. Results: The I/E ratios for the frontal lung area (1.25 ± 0.01), the lateral lung area (1.29 ± 0.01), and the lung distance (1.18 ± 0.01) were significantly (p < 0.05) reduced in COPD patients compared with controls (1.31 ± 0.02 and 1.38 ± 0.02, and 1.22 ± 0.01, respectively). The I/E ratios in frontal and lateral areas, and lung distance were significantly (p < 0.05) reduced in severe (GOLD stage III) and very severe (GOLD stage IV) COPD as compared to control subjects, although the I/E ratios did not differ significantly between severe and very severe COPD. Moreover, the I/E ratios were significantly correlated with pulmonary function parameters. Conclusions: Measurement of I/E ratios on paired I/E pCR is simple and

  4. Elimination of voltage reversal in multiple membrane electrode assembly installed microbial fuel cells (mMEA-MFCs) stacking system by resistor control.

    Science.gov (United States)

    Kim, Bongkyu; Chang, In Seop

    2018-08-01

    Voltage reversal (VR) in series connection of multiple membrane electrode assembly installed microbial fuel cells (mMEA-MFC) is eliminated by manipulating the resistor control. Discharge test results collected from two mMEA-MFCs initially operated (designated as P1 and P2) confirm that the performance of P2 exceeds that of P1. Thus, driving P1 and P2 as serially stacked MFCs generate the VR in P1. Controlling the inserted resistor adjust the current production of P2 to maintain balance with P1, and the VR in P1 is eliminated in the operation of stacking mode. Thus, manipulating the internal resistance provide an applicable approach to suppress VR in the stacking of mMEA-MFCs system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Pulmonary artery aneurysm

    African Journals Online (AJOL)

    Enrique

    Introduction. Pulmonary artery aneurysms are a rare finding in general radiological practice. The possible causes are myriad and diverse in pathophysiolo- gy. Patients with post-stenotic dilata- tion of the main pulmonary artery usually present fairly late with insidi- ous cardiorespiratory symptoms. Diagnosis requires ...

  6. Intratidal recruitment/derecruitment persists at low and moderate positive end-expiratory pressure in paediatric patients.

    Science.gov (United States)

    Wirth, Steffen; Artner, Lisa; Broß, Tobias; Lozano-Zahonero, Sara; Spaeth, Johannes; Schumann, Stefan

    2016-12-01

    In paediatric patients positive end-expiratory pressure (PEEP) is traditionally set lower than in adults. We investigated whether moderately higher PEEP improves respiratory mechanics and regional ventilation. Therefore, 40 children were mechanically ventilated with PEEP 2 and 5cmH 2 O. Volume-dependent compliance profiles were analysed as a measure of intratidal recruitment/derecruitment. Regional ventilation was assessed using electrical impedance tomography. Mean compliance was 17.9±9.9mLcmH 2 O -1 (PEEP 2cmH 2 O), and 19.0±10.9mLcmH 2 O -1 (PEEP 5 cmH 2 O, pventilation. In conclusion, mechanically ventilated paediatric patients undergo intratidal recruitment/derecruitment which occurs more prominently in younger than in older children. A PEEP of 5cmH 2 O does not fully prevent intratidal recruitment/derecruitment but homogenizes regional ventilation in comparison to 2cmH 2 O. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Expiratory CT in cigarette smokers: correlation between areas of decreased lung attenuation, pulmonary function tests and smoking history

    Energy Technology Data Exchange (ETDEWEB)

    Verschakelen, J.A.; Scheinbaum, K.; Bogaert, J.; Baert, A.L. [Department of Radiology, University Hospitals, Leuven (Belgium); Demedts, M.; Lacquet, L.L. [Department of Pneumology, University Hospitals, Leuven (Belgium)

    1998-10-01

    The aim of this study was to determine the correlation between cigarette-smoke-related bronchial disease and air trapping as assessed by expiratory high-resolution CT (HRCT) scans. Thirty healthy subjects (11 non-smokers, 7 ex-smokers for > 2 years, 12 current smokers; age range 35-55 years) with a smoking history between 0 and 28.5 pack-years underwent pulmonary function tests (PFT) and HRCT in inspiration and expiration in supine and prone position. The extent of air trapping was scored in ventral and dorsal aspects of the upper, middle and lower lung portions. In 24 subjects (7 non-smokers, 7 ex-smokers, 10 current smokers) areas of focal air trapping were found, and were present significantly more often in dependent lung portions (p < 0.05) compared with non-dependent portions. No significant differences were found between apical and basal lung zones. Scores of focal air trapping were not significantly different between smokers and ex-smokers, but were significantly lower (p < 0.05) in non-smokers and showed a significant (p < 0.0005) correlation with pack-years. The degree of air trapping was also associated with several lung function tests, especially RV, DLCO, FRC, FEV1 and FEV1/VC. Air trapping is seen in smokers with normal PFT and correlates with the severity of the smoking history, independently of current smoking status. (orig.) (orig.) With 4 figs., 4 tabs., 59 refs.

  8. Influence of Positive End-Expiratory Pressure on Myocardial Strain Assessed by Speckle Tracking Echocardiography in Mechanically Ventilated Patients

    Directory of Open Access Journals (Sweden)

    Federico Franchi

    2013-01-01

    Full Text Available Purpose. The effects of mechanical ventilation (MV on speckle tracking echocardiography- (STE-derived variables are not elucidated. The aim of the study was to evaluate the effects of positive end-expiratory pressure (PEEP ventilation on 4-chamber longitudinal strain (LS analysis by STE. Methods. We studied 20 patients admitted to a mixed intensive care unit who required intubation for MV and PEEP titration due to hypoxia. STE was performed at three times: (T1 PEEP = 5 cmH2O; (T2 PEEP = 10 cmH2O; and (T3 PEEP = 15 cmH2O. STE analysis was performed offline using a dedicated software (XStrain MyLab 70 Xvision, Esaote. Results. Left peak atrial-longitudinal strain (LS was significantly reduced from T1 to T2 and from T2 to T3 (. Right peak atrial-LS and right ventricular-LS showed a significant reduction only at T3 (. Left ventricular-LS did not change significantly during titration of PEEP. Cardiac chambers’ volumes showed a significant reduction at higher levels of PEEP (. Conclusions. We demonstrated for the first time that incremental PEEP affects myocardial strain values obtained with STE in intubated critically ill patients. Whenever performing STE in mechanically ventilated patients, care must be taken when PEEP is higher than 10 cmH2O to avoid misinterpreting data and making erroneous decisions.

  9. BILATERAL DUPLICATION OF RENAL ARTERIES

    OpenAIRE

    Prajkta A Thete; Mehera Bhoir; M.V.Ambiye

    2014-01-01

    Routine dissection of a male cadaver revealed the presence of bilateral double renal arteries. On the right side the accessory renal artery originated from the abdominal aorta just above the main renal artery. On the left side the accessory renal artery originated from the abdominal aorta about 1 cm above the main renal artery. Knowledge of the variations of renal vascular anatomy has importance in exploration and treatment of renal trauma, renal transplantation, renal artery embolization, su...

  10. Bilateral triple renal arteries

    International Nuclear Information System (INIS)

    Pestemalci, Turan; Yildiz, Yusuf Zeki; Yildirim, Mehmet; Mavi, Ayfer; Gumusburun, Erdem

    2009-01-01

    Knowledge of the variations of the renal artery has grown in importance with increasing numbers of renal transplants, vascular reconstructions and various surgical and radio logic techniques being performed in recent years. We report the presence of bilateral triple renal arteries, discovered on routine dissection of a male cadaver. On the right side, one additional renal artery originated from the abdominal aorta (distributed to superior pole of the kidney) and one other originated from the right common iliac artery (distributed to lower pole of the kidney). On the left side, both additional renal arteries originated from the abdominal aorta. Our observation has been compared with variations described in the literature and their clinical importance has been emphasized. (author)

  11. Occlusion of Heubner's artery

    International Nuclear Information System (INIS)

    Sato, Manabu; Kidooka, Minoru

    1982-01-01

    A case of occlusion of the left Heubner's artery in a right-handed, 51-year-old man is reported. Cardinal clinical features were transient right hemiparesis and mental disturbance, especially intellectual defect. Low density areas were found at CT in the globus pallidus, putamen, anterior limb of the internal capsule and a part of the caudate nucleus. It is well known that the occlusion of the Heubner's artery causes transient motor paresis of upper extremity on the contralaterl side. However, in the case where the Heubner's artery is remarkably well developed when compared with the medial striate arteries as was the case in this patient, it should be noted that the occlusion of the Heubner's artery may well causes grave mental disturbance, in addition. (author)

  12. LPG and NH3 Sensing Properties of SnO2 Thick Film Resistors Prepared by Screen Printing Technique

    Directory of Open Access Journals (Sweden)

    A. S. GARDE

    2010-11-01

    Full Text Available The gas sensing behavior of SnO2 thick film resistors deposited on alumina substrates has been investigated for LPG and NH3 gas. The standard screen printing technology was used to prepare the thick films. The films were fired at optimized temperature of 780 0C for 30 minutes. The material characterization was performed by XRD, SEM, FTIR, UV and EDAX for elemental analysis. IR spectroscopy analysis at 2949.26 cm-1 showed the peak assigned to the –Sn-H vibration due to the effect of hybridization i.e. sp3 and the sharp peak at 3734.31 cm-1 assigned to –Sn-OH stretching vibration due to hydrogen bonding. The variation of D.C electrical resistance of SnO2 film samples was measured in air as well as in LPG and NH3 gas atmosphere as a function of temperature. The SnO2 film samples show negative temperature coefficient of résistance. The SnO2 film samples showed the highest sensitivity to 600 ppm of LPG at 230 0C and NH3 at 370 0C. The effect of microstructure on sensitivity, response time and recovery time of the sensor in the presence of LPG and NH3 gases were studied and discussed.

  13. Electrical and Gas Sensing Properties of SnO2 Thick Film Resistors Prepared by Screen-printing Method

    Directory of Open Access Journals (Sweden)

    R. Y. BORSE

    2008-10-01

    Full Text Available Thick films of tin-oxide (SnO2 were deposited on alumina substrates employing screen-printing technique. The films were dried and fired at 680 0C for 30 minutes. The variation of D.C. resistance of thick films was measured in air as well as in H2S gas atmosphere as a function of temperature. The SnO2 films exhibit semiconducting behaviour. The SnO2 thick films studied were also showing decrease in resistance with increase of concentration of H2S gas. The film resistors showed the highest sensitivity to H2S gas at 350 0C. The XRD studies of the thick film indicate the presence of different phases of SnO2. The elemental analysis was confirmed by EDX spectra. The surface morphological study of the films was analyzed by SEM. The microstructure of the films was porous resulting from loosely interconnected small crystallites. The parameters such as grain size, activation energy, sensitivity and response time were described.

  14. Label-free electrical determination of trypsin activity by a silicon-on-insulator based thin film resistor.

    Science.gov (United States)

    Neff, Petra A; Serr, Andreas; Wunderlich, Bernhard K; Bausch, Andreas R

    2007-10-08

    A silicon-on-insulator (SOI) based thin film resistor is employed for the label-free determination of enzymatic activity. We demonstrate that enzymes, which cleave biological polyelectrolyte substrates, can be detected by the sensor. As an application, we consider the serine endopeptidase trypsin, which cleaves poly-L-lysine (PLL). We show that PLL adsorbs quasi-irreversibly to the sensor and is digested by trypsin directly at the sensor surface. The created PLL fragments are released into the bulk solution due to kinetic reasons. This results in a measurable change of the surface potential allowing for the determination of trypsin concentrations down to 50 ng mL(-1). Chymotrypsin is a similar endopeptidase with a different specificity, which cleaves PLL with a lower efficiency as compared to trypsin. The activity of trypsin is analyzed quantitatively employing a kinetic model for enzyme-catalyzed surface reactions. Moreover, we have demonstrated the specific inactivation of trypsin by a serine protease inhibitor, which covalently binds to the active site of the enzyme.

  15. Formation and dielectric properties of polyelectrolyte multilayers studied by a silicon-on-insulator based thin film resistor.

    Science.gov (United States)

    Neff, Petra A; Wunderlich, Bernhard K; Klitzing, Regine V; Bausch, Andreas R

    2007-03-27

    The formation of polyelectrolyte multilayers (PEMs) is investigated using a silicon-on-insulator based thin film resistor which is sensitive to variations of the surface potential. The buildup of the PEMs at the silicon oxide surface of the device can be observed in real time as defined potential shifts. The influence of polymer charge density is studied using the strong polyanion poly(styrene sulfonate), PSS, combined with the statistical copolymer poly(diallyl-dimethyl-ammoniumchloride-stat-N-methyl-N-vinylacetamide), P(DADMAC-stat-NMVA), at various degrees of charge (DC). The multilayer formation stops after a few deposition steps for a DC below 75%. We show that the threshold of surface charge compensation corresponds to the threshold of multilayer formation. However, no reversion of the preceding surface charge was observed. Screening of polyelectrolyte charges by mobile ions within the polymer film leads to a decrease of the potential shifts with the number of layers deposited. This decrease is much slower for PEMs consisting of P(DADMAC-stat-NMVA) and PSS as compared to PEMs consisting of poly(allylamine-hydrochloride), PAH, and PSS. From this, significant differences in the dielectric constants of the polyelectrolyte films and in the concentration of mobile ions within the films can be derived.

  16. An anthropomorphic transhumeral prosthesis socket developed based on an oscillometric pump and controlled by force-sensitive resistor pressure signals.

    Science.gov (United States)

    Razak, N A Abd; Gholizadeh, H; Hasnan, N; Osman, N A Abu; Fadzil, S S Mohd; Hashim, N A

    2017-02-01

    While considering the importance of the interface between amputees and prosthesis sockets, we study an anthropomorphic prosthesis socket whose size can be dynamically changed according to the requirements of the residual limb. First, we introduce the structure and function of the anthropomorphic prosthesis socket. Second, we study the dynamic model of the prosthesis system and analyze the dynamic characteristics of the prosthesis socket system, the inputs of an oscillometric pump, and the control mechanism of force-sensitive resistor (FSR) pressure signals. Experiments on 10 healthy subjects using the designed system yield an average detection result between 102 and 112 kPa for the FSR pressure sensor and 39 and 41 kPa for the oscillometric pump. Results show the function of the FSR pressure signal in maintaining the contact pressure between the sockets and the residual limb. The potential development of an auto-adjusted socket that uses an oscillometric pump system will provide prosthetic sockets with controllable contact pressure at the residual limb. Moreover, this development is an attractive research area for researchers involved in rehabilitation engineering, prosthetics, and orthotics.

  17. A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

    Science.gov (United States)

    Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

    2016-03-01

    Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

  18. Underlying Physics of Conductive Polymer Composites and Force Sensing Resistors (FSRs). A Study on Creep Response and Dynamic Loading.

    Science.gov (United States)

    Paredes-Madrid, Leonel; Matute, Arnaldo; Bareño, Jorge O; Parra Vargas, Carlos A; Gutierrez Velásquez, Elkin I

    2017-11-21

    Force Sensing Resistors (FSRs) are manufactured by sandwiching a Conductive Polymer Composite (CPC) between metal electrodes. The piezoresistive property of FSRs has been exploited to perform stress and strain measurements, but the rheological property of polymers has undermined the repeatability of measurements causing creep in the electrical resistance of FSRs. With the aim of understanding the creep phenomenon, the drift response of thirty two specimens of FSRs was studied using a statistical approach. Similarly, a theoretical model for the creep response was developed by combining the Burger's rheological model with the equations for the quantum tunneling conduction through thin insulating films. The proposed model and the experimental observations showed that the sourcing voltage has a strong influence on the creep response; this observation-and the corresponding model-is an important contribution that has not been previously accounted. The phenomenon of sensitivity degradation was also studied. It was found that sensitivity degradation is a voltage-related phenomenon that can be avoided by choosing an appropriate sourcing voltage in the driving circuit. The models and experimental observations from this study are key aspects to enhance the repeatability of measurements and the accuracy of FSRs.

  19. Degradation of GaAs/AlGaAs Quantized Hall Resistors With Alloyed AuGe/Ni Contacts.

    Science.gov (United States)

    Lee, Kevin C

    1998-01-01

    Careful testing over a period of 6 years of a number of GaAs/AlGaAs quantized Hall resistors (QHR) made with alloyed AuGe/Ni contacts, both with and without passivating silicon nitride coatings, has resulted in the identification of important mechanisms responsible for degradation in the performance of the devices as resistance standards. Covering the contacts with a film, such as a low-temperature silicon nitride, that is impervious to humidity and other contaminants in the atmosphere prevents the contacts from degrading. The devices coated with silicon nitride used in this study, however, showed the effects of a conducting path in parallel with the 2-dimensional electron gas (2-DEG) at temperatures above 1.1 K which interferes with their use as resistance standards. Several possible causes of this parallel conduction are evaluated. On the basis of this work, two methods are proposed for protecting QHR devices with alloyed AuGe/Ni contacts from degradation: the heterostructure can be left unpassivated, but the alloyed contacts can be completely covered with a very thick (> 3 μm) coating of gold; or the GaAs cap layer can be carefully etched away after alloying the contacts and prior to depositing a passivating silicon nitride coating over the entire sample. Of the two, the latter is more challenging to effect, but preferable because both the contacts and the heterostructure are protected from corrosion and oxidation.

  20. Whole-lung volume and density in spirometrically-gated inspiratory and expiratory CT in systemic sclerosis: correlation with static volumes at pulmonary function tests.

    Science.gov (United States)

    Camiciottoli, G; Diciotti, S; Bartolucci, M; Orlandi, I; Bigazzi, F; Matucci-Cerinic, M; Pistolesi, M; Mascalchi, M

    2013-03-01

    Spiral low-dose computed tomography (LDCT) permits to measure whole-lung volume and density in a single breath-hold. To evaluate the agreement between static lung volumes measured with LDCT and pulmonary function test (PFT) and the correlation between the LDCT volumes and lung density in restrictive lung disease. Patients with Systemic Sclerosis (SSc) with (n = 24) and without (n = 16) pulmonary involvement on sequential thin-section CT and patients with chronic obstructive pulmonary disease (COPD)(n = 29) underwent spirometrically-gated LDCT at 90% and 10% of vital capacity to measure inspiratory and expiratory lung volumes and mean lung attenuation (MLA). Total lung capacity and residual volume were measured the same day of CT. Inspiratory [95% limits of agreement (95% LoA)--43.8% and 39.2%] and expiratory (95% LoA -45.8% and 37.1%) lung volumes measured on LDCT and PFT showed poor agreement in SSc patients with pulmonary involvement, whereas they were in substantial agreement (inspiratory 95% LoA -14.1% and 16.1%; expiratory 95% LoA -13.5% and 23%) in SSc patients without pulmonary involvement and in inspiratory scans only (95% LoA -23.1% and 20.9%) of COPD patients. Inspiratory and expiratory LDCT volumes, MLA and their deltas differentiated both SSc patients with or without pulmonary involvement from COPD patients. LDCT lung volumes and density were not correlated in SSc patients with pulmonary involvement, whereas they did correlate in SSc without pulmonary involvement and in COPD patients. In restrictive lung disease due to SSc there is poor agreement between static lung volumes measured using LDCT and PFT and the relationship between volume and density values on CT is altered.

  1. Is increased positive end-expiratory pressure the culprit? Autoresuscitation in a 44-year-old man after prolonged cardiopulmonary resuscitation: a case report

    OpenAIRE

    Hagmann, Henning; Oelmann, Katrin; Stangl, Robert; Michels, Guido

    2016-01-01

    Background The phenomenon of autoresuscitation is rare, yet it is known to most emergency physicians. However, the pathophysiology of the delayed return of spontaneous circulation remains enigmatic. Among other causes hyperinflation of the lungs and excessively high positive end-expiratory pressure have been suggested, but reports including cardiopulmonary monitoring during cardiopulmonary resuscitation are scarce to support this hypothesis. Case presentation We report a case of autoresuscita...

  2. Renal artery stenosis

    International Nuclear Information System (INIS)

    Desberg, A.; Paushter, D.M.; Lammert, G.K.; Hale, J.; Troy, R.; Novic, A.; Nally, J. Jr.

    1989-01-01

    Renal artery disease is a potentially correctable cause of hypertension. Previous studies have suggested the utility of duplex sonography in accurately detecting and grading the severity of renal artery stenosis. The purpose of this paper is to evaluate color flow Doppler for this use. Forty-three kidneys were examined by color-flow Doppler and conventional duplex sampling in patients with suspected renovascular hypertension or those undergoing aortography for unrelated reasons. Doppler tracings were obtained from the renal arteries and aorta with calculation of the renal aortic ratio (RAR) and resistive index (RI). Results of Doppler sampling with color flow guidance were compared with aortograms in a blinded fashion

  3. Coronary artery aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Koischwitz, D.; Harder, T.; Schuppan, U.; Thurn, P.

    1982-04-01

    Seven saccular coronary artery aneurysms have been demonstrated in the course of 1452 selective coronary artery angiograms. In six patients they were arterio-sclerotic; in one patient the aneurysm must have been congenital or of mycotic-embolic origin. The differential diagnosis between true aneurysms and other causes of vascular dilatation is discussed. Coronary artery aneurysms have a poor prognosis because of the possibility of rupture with resultant cardiac tamponade, or the development of thrombo-embolic myocardial infarction. These aneurysms can only be diagnosed by means of coronary angiography and require appropriate treatment.

  4. Vertebrobasilar Artery Occlusion

    Directory of Open Access Journals (Sweden)

    Schoen, Jessica

    2011-05-01

    Full Text Available The presentation of vertebrobasilar artery occlusion varies with the cause of occlusion and location of ischemia. This often results in delay in diagnosis. Areas of the brain supplied by the posterior circulation are difficult to visualize and usually require angiography or magnetic resonance imaging. Intravenous thrombolysis and local-intra arterial thrombolysis are the most common treatment approaches used. Recanalization of the occluded vessel significantly improves morbidity and mortality. Here we present a review of the literature and a case of a patient with altered mental status caused by vertebrobasilar artery occlusion. [West J Emerg Med. 2011;12(2:233-239.

  5. A Simple Measure to Assess Hyperinflation and Air Trapping: 1-Forced Expiratory Volume in Three Second / Forced Vital Capacity

    Directory of Open Access Journals (Sweden)

    Sermin Börekçi

    2017-04-01

    Full Text Available Background: Several recent studies have suggested that 1 minus-forced expiratory volume expired in 3 seconds / forced vital capacity (1-FEV3/FVC may be an indicator of distal airway obstruction and a promising measure to evaluate small airways dysfunction. Aims: To investigate the associations of 1-FEV3/FVC with the spirometric measures and lung volumes that assess small airways dysfunction and reflects hyperinflation and air trapping. Study Design: Retrospective cross-sectional study. Methods: Retrospective assessment of a total of 1110 cases who underwent body plethysmographic lung volume estimations between a time span from 2005 to 2012. Patients were assigned into two groups: firstly by FEV1/FVC (FEV1/FVC <70% vs. FEV1/FVC ≥70%; secondly by FEV3/FVC < lower limits of normal (LLN (FEV3/FVC < LLN vs. FEV3/FVC ≥ LLN. Spirometric indices and lung volumes measured by whole-body plethysmography were compared in groups. Also the correlation of spirometric indices with measured lung volumes were assessed in the whole-study population and in subgroups stratified according to FEV1/FVC and FEV3/FVC. Results: Six hundred seven (54.7% were male and 503 (45.3% were female, with a mean age of 52.5±15.6 years. Mean FEV3/FVC and 1-FEV3/FVC were 87.05%, 12.95%, respectively. The mean 1-FEV3/FVC was 4.9% in the FEV1/FVC ≥70% group (n=644 vs. 24.1% in the FEV1/FVC <70% group (n=466. A positive correlation was found between 1-FEV3/FVC and residual volume (r=0.70; p<0.0001, functional residual capacity-pleth (r=0.61; p<0.0001, and total lung capacity (r=0.47; p<0.0001. 1-FEV3/FVC was negatively correlated with forced expiratory flow25-75 (r=−0.84; p<0.0001. The upper limit of 95% confidence interval for 1-FEV3/FVC was 13.7%. 1-FEV3/FVC showed significant correlations with parameters of air trapping and hyperinflation measured by whole-body plethysmography. Importantly, these correlations were higher in study participants with FEV1/FVC <70% or FEV3/FVC

  6. Validation of a protocol to evaluate maximal expiratory pressure using a pressure transducer and a signal conditioner

    Directory of Open Access Journals (Sweden)

    Viviane Soares

    2011-09-01

    Full Text Available The respiratory muscles can present fatigue and even chronic inability to generate force. So, reliable devices are necessary to their evaluation. The aim of this study is to evaluate the MEP (Maximal Expiratory Pressure values of individuals between 20 and 25 years old and to validate a protocol using a pressure transducer and a signal conditioner comparing it with the digital manometer. We evaluated the MEP of 10 participants. They remained seated and made six respiratory maneuvers from Total Lung Capacity (TLC to Residual Volume (RV. The results in the study showed no statistically significant differences when compared to values reported in the literature, and that the pressure transducer provides reliable values for MEP.Os músculos respiratórios podem apresentar fadiga e até mesmo a incapacidade crônica na geração de força, sendo necessários dispositivos confiáveis para sua avaliação. O objetivo deste estudo foi avaliar a pressão expiratória máxima (PeMáx de indivíduos entre 20 e 25 anos e validar um protocolo que utiliza um transdutor de pressão e um condicionador de sinais comparando-o com a manovacuometria. Foram avaliadas a PeMáx de 10 participantes. Estes permaneceram sentados e realizaram seis manobras respiratórias a partir da capacidade pulmonar total (CPT até o volume residual (VR. Os resultados do estudo não apresentaram diferenças estatisticamente significativas quando comparados com os valores de normalidade descritos na literatura e mostraram que o transdutor de pressão fornece valores confiáveis para Pe máx.

  7. [Value of forced expiratory volume in 6 seconds (FEV(6)) in the evaluation of pulmonary function in Chinese elderly males].

    Science.gov (United States)

    Pan, M M; Zhang, H S; Sun, T Y

    2017-05-30

    Objective: To evaluate the value of forced expiratory volume in 6 seconds (FEV(6)) in the evaluation of pulmonary function in Chinese elderly males. Methods: Pulmonary function tests of elderly who had received regular physical examination in Beijing Hospital from July 2003 to April 2015 were analyzed on subjects with the following characteristics: aged 60 years or older, completion of bronchial dilation test and able to exhale for at least six seconds. The included subjects were divided into 2 groups: 60-function in the study population was evaluated. Results: A total of 475 elderly men aged 60 years or older were enrolled, with a mean age of (77.13±9.53) years. Totally there were 269 subjects in 60-accounted for 56.6%; 206 subjects were in ≥80 years group, which accounted for 43.4%. There were 292 subjects with irreversible airflow obstruction, accounting for 61.5%. In all the included subjects, FEV(6) was significantly correlated with FVC and post-bronchodilator FEV(1)/FEV(6) was significantly correlated with post-bronchodilator FEV(1)/FVC( r =0.971, 0.978; both P function middle group, a total of 73 cases, which included 20 cases ≥80 years old. The proportion of middle group among ≥80 years group was significantly less than that of the 60-function middle group, FEV(1)/FEV(6) or FEV(1)/FVC had no correlation with inspiratory capacity or residual volume/total lung capacity (all P >0.05). Conclusions: FEV(6) and FEV(1)/FEV(6) are strongly correlated with FVC and FEV(1)/FVC, and there is excellent agreement between FEV(1)/FEV(6) and FEV(1)/FVC. FEV(6) is simple, easy to operate and with less influencing factors, which can be used as a valid alternative for FVC in diagnosing airflow obstruction in elderly males.

  8. Peripheral chemoreceptors tune inspiratory drive via tonic expiratory neuron hubs in the medullary ventral respiratory column network.

    Science.gov (United States)

    Segers, L S; Nuding, S C; Ott, M M; Dean, J B; Bolser, D C; O'Connor, R; Morris, K F; Lindsey, B G

    2015-01-01

    Models of brain stem ventral respiratory column (VRC) circuits typically emphasize populations of neurons, each active during a particular phase of the respiratory cycle. We have proposed that "tonic" pericolumnar expiratory (t-E) neurons tune breathing during baroreceptor-evoked reductions and central chemoreceptor-evoked enhancements of inspiratory (I) drive. The aims of this study were to further characterize the coordinated activity of t-E neurons and test the hypothesis that peripheral chemoreceptors also modulate drive via inhibition of t-E neurons and disinhibition of their inspiratory neuron targets. Spike trains of 828 VRC neurons were acquired by multielectrode arrays along with phrenic nerve signals from 22 decerebrate, vagotomized, neuromuscularly blocked, artificially ventilated adult cats. Forty-eight of 191 t-E neurons fired synchronously with another t-E neuron as indicated by cross-correlogram central peaks; 32 of the 39 synchronous pairs were elements of groups with mutual pairwise correlations. Gravitational clustering identified fluctuations in t-E neuron synchrony. A network model supported the prediction that inhibitory populations with spike synchrony reduce target neuron firing probabilities, resulting in offset or central correlogram troughs. In five animals, stimulation of carotid chemoreceptors evoked changes in the firing rates of 179 of 240 neurons. Thirty-two neuron pairs had correlogram troughs consistent with convergent and divergent t-E inhibition of I cells and disinhibitory enhancement of drive. Four of 10 t-E neurons that responded to sequential stimulation of peripheral and central chemoreceptors triggered 25 cross-correlograms with offset features. The results support the hypothesis that multiple afferent systems dynamically tune inspiratory drive in part via coordinated t-E neurons. Copyright © 2015 the American Physiological Society.

  9. Is there an optimal level of positive expiratory pressure (PEP) to improve walking tolerance in patients with severe COPD?

    Science.gov (United States)

    Russo, Davide; Simonelli, Carla; Paneroni, Mara; Saleri, Manuela; Piroddi, Ines Maria Grazia; Cardinale, Francesco; Vitacca, Michele; Nicolini, Antonello

    2016-07-01

    The application of positive expiratory pressure (PEP) devices during exercise had been proposed in order to counteract the pulmonary hyperinflation, reduce the dyspnea and thus increase the exercise tolerance in patients with severe chronic obstructive pulmonary disease (COPD). This randomized controlled crossover trial investigated the effect of two different levels of PEP (1 cmH2O and 10 cmH2O) on distance covered at 6minute walk test (6MWT) in patients with severe COPD. Secondary outcomes were the evaluation of PEP effects on physiological and pulmonary function variables. Seventy-two severe COPD patients, referred to our hospitals as in and out patients, were recruited. A basal 6MWT without devices was performed on the first day, and then repeated with PEP 1 cmH2O (PEP1) and 10 cmH2O (PEP10), with a randomized crossover design. Slow and forced spirometries, including the inspiratory capacity measure, were repeated before and after each 6MWT. 50 patients (average age 69,92 year, mean FEV1 41,42% of predicted) concluded the trial. The 6MWT improved significantly among both PEP levels and baseline (323,8 mt at baseline vs. 337,8 PEP1 and 341,8 PEP10; p<.002 and p<.018, respectively). The difference between PEP10 and PEP1 did not reach the significance. No improvements were found in pulmonary function, symptoms and physiological variables after the 6MWT. In patients with severe COPD, the application of 1 cmH2O of PEP seems to improve the exercise tolerance as 10 cmH2O, with similar dyspnea. Further studies should investigate the effects of low levels of PEP on aerobic training programs. Copyright © 2016 SEPAR. Published by Elsevier Espana. All rights reserved.

  10. Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals

    Directory of Open Access Journals (Sweden)

    Isabella Martins de Albuquerque

    Full Text Available ABSTRACT Objective: To evaluate the effects of positive expiratory pressure (PEP on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10, 15 cmH2O (n = 10, and 20 cmH2O (n = 10. The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044, 15 cmH2O (p = 0.044, and 20 cmH2O (p = 0.004-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.

  11. Relationship between spontaneous expiratory flow-volume curve pattern and air-flow obstruction in elderly COPD patients.

    Science.gov (United States)

    Nozoe, Masafumi; Mase, Kyoshi; Murakami, Shigefumi; Okada, Makoto; Ogino, Tomoyuki; Matsushita, Kazuhiro; Takashima, Sachie; Yamamoto, Noriyasu; Fukuda, Yoshihiro; Domen, Kazuhisa

    2013-10-01

    Assessment of the degree of air-flow obstruction is important for determining the treatment strategy in COPD patients. However, in some elderly COPD patients, measuring FVC is impossible because of cognitive dysfunction or severe dyspnea. In such patients a simple test of airways obstruction requiring only a short run of tidal breathing would be useful. We studied whether the spontaneous expiratory flow-volume (SEFV) curve pattern reflects the degree of air-flow obstruction in elderly COPD patients. In 34 elderly subjects (mean ± SD age 80 ± 7 y) with stable COPD (percent-of-predicted FEV(1) 39.0 ± 18.5%), and 12 age-matched healthy subjects, we measured FVC and recorded flow-volume curves during quiet breathing. We studied the SEFV curve patterns (concavity/convexity), spirometry results, breathing patterns, and demographics. The SEFV curve concavity/convexity prediction accuracy was examined by calculating the receiver operating characteristic curves, cutoff values, area under the curve, sensitivity, and specificity. Fourteen subjects with COPD had a concave SEFV curve. All the healthy subjects had convex SEFV curves. The COPD subjects who had concave SEFV curves often had very severe airway obstruction. The percent-of-predicted FEV(1)% (32.4%) was the most powerful SEFV curve concavity predictor (area under the curve 0.92, 95% CI 0.83-1.00), and had the highest sensitivity (0.93) and specificity (0.88). Concavity of the SEFV curve obtained during tidal breathing may be a useful test for determining the presence of very severe obstruction in elderly patients unable to perform a satisfactory FVC maneuver.

  12. Diaphragmatic thickness ratio (inspiratory/expiratory) as a diagnostic method of diaphragmatic palsy associated with interescalene block.

    Science.gov (United States)

    López Escárraga, V M; Dubos España, K; Castillo Bustos, R H; Peidró, L; Sastre, S; Sala-Blanch, X

    2018-02-01

    Diaphragmatic paralysis is a side-effect associated with interscalene block. Thickness index of the diaphragm muscle (inspiratory thickness/expiratory thickness) obtained by ultrasound has recently been introduced in clinical practice for diagnosis of diaphragm muscle atrophy. Our objective was to evaluate this index for the diagnosis of acute phrenic paresis associated with interscalene block. We designed an observational study in 22 patients scheduled for shoulder arthroscopy. Spirometry was performed (criteria of phrenic paresis was a decrease in FVC and FEV1 ≥20%). Ultrasound apposition zone was assessed in anterior axillary line and diaphragmatic displacement was evaluated on inspiration and expiration (number of intercostal spaces; phrenic paresis considered a reduction ≥25%) and thickness of the diaphragm muscle (a phrenic paresis was considered an index block at C5-C6 with 20ml of 0.5% ropivacaine. Twenty-one patients (95%) presented phrenic nerve block according to one or more of the methods used. One patient did not show any symptoms or signs suggestive of phrenic paralysis and was excluded. All the patients presented phrenic paresis based on the diaphragmatic thickness index, with the pre-block index being 1.8±0.5 and post-block of 1.05±0.06 (Pblock (from 1.9±0.5 intercostal spaces to 0.5±0.3; Pblock. This index does not require a baseline pre-assessment. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Effect of bedding control on amount of house dust mite allergens, asthma symptoms, and peak expiratory flow rate.

    Science.gov (United States)

    Lee, Inn-Sook

    2003-04-30

    This quasi-experimental study was designed to investigate the effect of bedding control on the amount of house dust mite (HDM) allergens, asthma symptoms, and peak expiratory flow rate (PEFR) in asthmatics sensitive to HDMs. The subjects in the study were drawn from patients receiving treatment at the allergy clinics of three university-affiliated hospitals in Seoul. Forty-two patients without prior practice of the bedding control used in this study were selected. They commonly showed bronchial asthma caused by HDMs, and exhibited strong positive points (more than 3 points) in skin prick test (D. farinae, D. pteronyssinus), and positive response in both fluoro-allergosorbent test (FAST), and PC20 methacholine test. Of the subjects, alternatively, 22 were assigned to the experimental group and 20 to control group. Bedding control consisted of the use of outer cotton covers, boiling them for 10 minutes fortnightly, and disinfecting bedding by sunlight fortnightly. The experimental group was under bedding control for 4 weeks. The data were collected from October 2000 to January 2001. The results were as follows: 1. After bedding control, the total amount of HDM allergens decreased significantly in the experimental group. However there was no significant difference in the decrease of the amount of HDM allergens between the two groups. 2. Of the asthma symptoms, there was significant difference only in the decrease of the frequency of dyspnea, and in the increase of sleeping disturbance between the two groups after bedding control. 3. After bedding control, PEFR increased in the experimental group whereas it decreased in the control group. However, neither change was significant. The above findings indicate that bedding control improved several asthma symptoms in asthmatics sensitive to HDMs. Accordingly, we suggest that bedding control is adopted as a useful nursing intervention in the field.

  14. Effects of positive end-expiratory pressure on intraoperative core temperature in patients undergoing posterior spine surgery: prospective randomised trial.

    Science.gov (United States)

    Seo, Hyungseok; Do Son, Je; Lee, Hyung-Chul; Oh, Hyung-Min; Jung, Chul-Woo; Park, Hee-Pyoung

    2018-03-01

    Objective Positive end-expiratory pressure (PEEP) causes carotid baroreceptor unloading, which leads to thermoregulatory peripheral vasoconstriction. However, the effects of PEEP on intraoperative thermoregulation in the prone position remain unknown. Methods Thirty-seven patients undergoing spine surgery in the prone position were assigned at random to receive either 10 cmH 2 O PEEP (Group P) or no PEEP (Group Z). The primary endpoint was core temperature 180 minutes after intubation. Secondary endpoints were delta core temperature (difference in core temperature between 180 minutes and immediately after tracheal intubation), incidence of intraoperative hypothermia (core temperature of peripheral vasoconstriction-related data. Results The median [interquartile range] core temperature 180 minutes after intubation was 36.1°C [35.9°C-36.2°C] and 36.0°C [35.9°C-36.4°C] in Groups Z and P, respectively. The delta core temperature and incidences of intraoperative hypothermia and peripheral vasoconstriction were not significantly different between the two groups. The peripheral vasoconstriction threshold (36.2°C±0.5°C vs. 36.7°C±0.6°C) was lower and the onset of peripheral vasoconstriction (66 [60-129] vs. 38 [28-70] minutes) was slower in Group Z than in Group P. Conclusions Intraoperative PEEP did not reduce the core temperature decrease in the prone position, although it resulted in an earlier onset and higher threshold of peripheral vasoconstriction.

  15. [Endarterectomy of the coronary arteries].

    Science.gov (United States)

    Fischer, V; Simkovic, I; Holoman, M; Verchvodko, P; Janotík, P; Galbánek, J; Hulman, M; Kostelnicák, J; Jurco, R; Slezák, J

    1992-02-01

    The authors analyze 50 patients with endarterectomy of the coronary arteries during the periods of 1972-1974 and 1988-1990. The results of endarterectomy of the right and left coronary artery provide evidence of its justification in indicated cases whereby contrary to some departments the results of endarterectomy of the left coronary artery are comparable with endarterectomy of the right coronary artery.

  16. Popliteal Arterial Aneurysms

    African Journals Online (AJOL)

    plication was acute arterial occlusion caused by thrombo- embolism. The reasons for ... Total. 43. 55. TABLE 11. CONCOMITANT DISEASE IN 38 PATIENTS .... Dacron prosthesis in 4. .... genous saphenous vein and the type of anastomosis.

  17. Coronary artery fistula

    Science.gov (United States)

    ... PA: Elsevier Saunders; 2015:chap 84. Friedman AH, Silverman NH. Congenital anomalies of the coronary arteries. In: ... provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  18. Thermosetting polyimide resin matrix composites with interpenetrating polymer networks for precision foil resistor chips based on special mechanical performance requirements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.Y., E-mail: wxy@tju.edu.cn [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Ma, J.X.; Li, C.G. [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Wang, H.X. [ZHENGHE electronics Co., Ltd, Jining 272023 (China)

    2014-04-01

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: Based on interpenetrating networks (IPNs) different macromolecular materials such as epoxy, phenolic, and silicone resin were chosen to modify thermosetting polyimide (TSPI) resin to solve the lack of performance when used for protecting precision foil resistor chips. Copolymerization modification, controlled at curing stage, was used to prepare TSPI composites considering both performance and process requirements. The mechanical properties related to trimming process were mainly studied due to the special requirements of the regularity of scratch edges caused by a tungsten needle. The analysis on scratch edges reveals that the generation and propagation of microcracks caused by scratching together with crack closure effect may lead to regular scratch traces. Experiments show that the elongation at break of TSPI composites is the main reason that determines the special mechanical properties. The desired candidate materials should have proper hardness and toughness, and the specific mechanical data are that the mean elongation at break and tensile strength of polymer materials are in the range of 9.2–10.4% and 100–107 MPa, respectively. Possible reasons for the effect of the modifiers chosen on TSPI polymers, the reaction mechanisms on modified TSPI resin and the IPN structure in TSPI composite polymers were discussed based on IR and TG analysis.

  19. Thermosetting polyimide resin matrix composites with interpenetrating polymer networks for precision foil resistor chips based on special mechanical performance requirements

    International Nuclear Information System (INIS)

    Wang, X.Y.; Ma, J.X.; Li, C.G.; Wang, H.X.

    2014-01-01

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: Based on interpenetrating networks (IPNs) different macromolecular materials such as epoxy, phenolic, and silicone resin were chosen to modify thermosetting polyimide (TSPI) resin to solve the lack of performance when used for protecting precision foil resistor chips. Copolymerization modification, controlled at curing stage, was used to prepare TSPI composites considering both performance and process requirements. The mechanical properties related to trimming process were mainly studied due to the special requirements of the regularity of scratch edges caused by a tungsten needle. The analysis on scratch edges reveals that the generation and propagation of microcracks caused by scratching together with crack closure effect may lead to regular scratch traces. Experiments show that the elongation at break of TSPI composites is the main reason that determines the special mechanical properties. The desired candidate materials should have proper hardness and toughness, and the specific mechanical data are that the mean elongation at break and tensile strength of polymer materials are in the range of 9.2–10.4% and 100–107 MPa, respectively. Possible reasons for the effect of the modifiers chosen on TSPI polymers, the reaction mechanisms on modified TSPI resin and the IPN structure in TSPI composite polymers were discussed based on IR and TG analysis

  20. The Development Of Windows Service Based Data Log System Using Light Dependent Resistor And Thingspeak IOT Cloud Platform

    Directory of Open Access Journals (Sweden)

    Tristan Jay P. Calaguas

    2017-03-01

    Full Text Available Microcontrollers are using in control and information processing it can be used in wide application such as agriculture health care commercial facilities robotics and education. These micro controllers are computers in chip that comprises of input and output ports central processing unit registers and main memory as well as communication interface such as Ethernet interface serial interface High Definition Multimedia Interface power source and many existing interface that can be found in this type of computer. In this study the researcher decided to conceptualize an innovative application of this type of computer where it has a potential to use as tracking system in specific individuals activities. Since some of office people are complaining in CCTV camera about their privacy this innovative concept of technology is in similar purpose but if we will compare the application concept in closed circuit camera the researcher decided to use visual graph instead video data that is in high exposure In the first phase the researcher made a concept on how the simple Light Dependent Resistor will apply in Schools Office Environment Application domain using microcontroller that was used as data log system and how this can be optimized without forcing the Dean or any designated person in office to operate it in hand due to their busy working hours. In the second phase the researcher develop the proposed data log system that are acquiring data through light luminance from fluorescent light of deans office and sending it in the IOT cloud platform. The researcher used fuzzy logic theory to model the operation of the proposed data log system. This study used experimental type of research when the prototype was developed during second phase the researcher simulated the operation. As the result the proposed data log system is sending data to Thingspeak IOT Cloud platform it displays the correct output which based from the rules and it is in column graph content